Field of the invention

[0001] The present invention relates to an apparatus for flexographic printing and a method of forming and operating the apparatus. More specifically, the present invention relates to an apparatus and a method for mounting and/or demounting printing forms to and/or from a main body, e.g., an adaptor, a base cylinder, and/or a print cylinder, of the apparatus. Even more specifically, the present invention relates to an apparatus and a method for mounting and/or demounting an In The Round (ITR) type of printing form to and/or from a cylindrically shaped base adapter.

Background art

[0002] A section view of a typical flexographic printing process/apparatus is shown in Fig. 1 . In general, a flexible printing form, normally in the shape of a plate, is mounted to a plate cylinder of a printing press, properly inked, and then contacted to a substrate to print the desired pattern on the substrate, as shown in Fig. 1. A typical flexographic printing process/apparatus 100 comprises an ink fountain 101 , a screen roll (or a fountain roll) 102, a metering system 103 and 104, a printing plate/form 105, a plate cylinder 106 to which the printing plate 105 is attached, an impression cylinder 107 and a substrate 108 to which the pattern is to be printed. Hereafter, the terms“printing form”, and“flexible printing form", are used interchangeably, and the terms“plate cylinder” and“print cylinder” are used interchangeably too.

[0003] The ink fountain 101 comprises a certain amount of ink. Its viscosity depends on the required application, as persons skilled in the art know. The screen roll 102 loads the ink from the ink fountain 101 and supplies the loaded ink to the printing form 105. Before the loaded ink is supplied to the printing form 105, a metering system 103 and 104 may be used. The metering system may comprise a blade 103 and an anilox roll 104 . The main purpose of the metering system 103 and 104 is to provide a desired amount of ink evenly or unevenly to the printing form 105 in dependence on the pattern on the surface of the printing form 105.

[0004] The blade 103 is used to scrape off superfluous ink from the surface of the anilox roll 104 such as to evenly distribute the ink along the anilox roll's surface. The anilox roll 104 comprises a certain surface pattern designed to absorb ink from the screen roll 102 for further transfer to the printing form 105. This surface pattern may have small cells or one or more channels extending along the circumferential direction of the anilox roll 104, as is e.g. explained in WO09082225. The anilox roll 104 may be omitted, in which case the blade 103 is arranged such as to scrape off superfluous ink from the screen roll 102. The printing form 105 comprises a printing pattern to be printed on the substrate 108 (e.g., paper, clothes, plastic sheets, etc.). The substrate 108 is placed in between the printing form 105 and the impression cylinder 107. For multi-colour printing, sequential processes as shown in Fig. 1 may be needed, each of which prints at least one colour on the substrate 108.

[0005] Flat plate shaped printing forms may not be suitable for some printing processes. Therefore, a cylindrically shaped In The Round (ITR) type of flexible printing forms, as shown in Fig. 1 , are commonly used in flexographic printing. These ITR flexible printing forms are also known as continuous printing forms, sleeves, printing sleeves, or endless sleeves, which terms are used interchangeably hereafter in this application. The ITR flexible printing forms are advantageous in some continuous printing processes, e.g., wallpaper, decoration and gift wrapping paper, and also provide better printing patterns without visual plate joints and/or visible plate seams.

[0006] An ITR flexible printing form can be directly mounted to the print cylinder 106. Or, an ITR flexible printing form may have a plate-on-sleeve structure, which comprises a cylindrically shaped printing support in sleeve shape and at least one printing plate. The flexible printing form is mounted to the cylindrically shaped support. Such continuous ITR printing forms are well-suited for mounting with laser guiding/pointing equipment for accurate registrations in multi-colour printing.

[0007] Of course, the flexible printing forms may be in other forms known in the industry.

[0008] When mounting the printing form 105 to the print cylinder 106, in the prior art, pressurized gas (e.g., air, nitrogen or any other suitable gas; Air is preferred to be used; However, other types of gas are also possible and air is merely used as an example in this application) is injected at one end of the print cylinder 106 and emerges through openings/through-holes at the exterior surface of the print cylinder 106 (not shown in Fig. 1). The through-holes are usually arranged angularly on the surface of the print cylinder 106. The emerged air via the through-holes may create an air cushion between the print cylinder 106 and the printing form 105, when the printing form 105 is mounted to or demounted from the print cylinder 106. The air cushion may cause a slight radial expansion of the flexible printing form 105 and allows the printing form 105 to be easily moveable along and around the print cylinder 106. The printing form 105 may be easily moved to a predefined position on the print cylinder 106 because of the air cushion, after which the air pressure is turned off such that the printing form 105 contracts and forms a tide fit around the print cylinder 106. By this process, the printing form 105 may retain at the predefined position tightly while printing. A similar procedure may be used to demount a printing form 105 from the print cylinder 106.

[0009] Fig. 2 is a cross sectional diagram showing an example of a known mounting process of a printing form 220 to a print cylinder 210 by means of air cushions, as will be explained below. More specifically, Fig. 2 provides an example of attaching a printing form 220 to the surface of a print cylinder 210. It is observed that, here, when the printing form 220 is attached to the print cylinder 210, the term“attached” (or“retained/retaining”) refers to a state in which the printing form 220 cannot or can hardly be moved relative to the print cylinder 210. The “attachment” can be implemented by a clamping force only.

[0010] Inside print cylinder 210, there is an air channel or compartment 213 connecting an air supply from an air inlet channel 214 to one or more through-holes, e.g., 21 1 and 212. Print cylinder 210 comprises one spindle part on each side, such that print cylinder 210 may spin about a central axial line 230.

When printing form 220 is being mounted to the print cylinder 210 as shown in Fig. 2, air is supplied from a source, e.g., a suitable pump (not shown) connected to the air inlet channel 214. Then, the air flows via the compartment 213 to the through-holes, e.g., 21 1 and 212. When the printing form 220 covers at least one of the through-holes, e.g., through-hole 212 is covered, an air cushion is formed between the printing form 220 and the print cylinder 210 by air pressure of the air flow, which enables the printing form 220 to be moved easily on the print cylinder 210 axially and/or rotationally. The equation for the calculating of the sleeve expansion as a result of the applied air pressure is:

D = Diameter of the sleeve in mm

P = Air pressure (dynamic) in N/mm ²

E = E-module in circumference in N/mm ²

S = Wall thickness of the sleeve in mm

AD = Expansion of the sleeve in mm

[0011] Such an axial and/or rotational movement can be done manually or by a machine in order to position the printing form 220 in its desired position on the outer surface of the print cylinder 210.

[0012] However, when multiple printing forms need to be mounted to the print cylinder 210 side by side, it is problematic to accurately positioning the printing forms. For example, after the air supply is turned on and a first printing form is already mounted, a second printing form needs to be mounted to the print cylinder 210. In this case, it is difficult to keep the first printing form at the predefined position because of the air cushion generated to position the second printing form (the air supply is still turned on). Even a slight position inaccuracy of the first printing form may reduce the printing quality severely.

[0013] Document US 2008/0250960 A1 provides a method and apparatus for mounting two or more cylindrically-shaped printing forms onto a cylindrically-shaped base. The two or more printing forms are axially oriented on the print cylinder using pressurized air as an air cushion between the printing cylinder and the printing forms, positioned in a registration position, and engaged by a holding member to maintain the two or more printing forms in their respective registration position.

[0014] However, the holding member may damage the printing patterns on the surface of the printing form. Especially when the holding member holds on a certain point of the printing form all the time it may cause permanent damage to the printing forms and the print cylinder.

[0015] Additionally, it is also a waste of energy when mounting a printing form which is axially much shorter than the print cylinder, because the air supplies to all the through-holes need to be turned on during the whole mounting process.

[0016] Furthermore, the air pressure to through-holes is always the same, which is not satisfactory in some situations. For example, because of the difference in material and structure of printing forms, a first printing form may be efficiently expanded for easy mounting by a certain air pressure, but a second printing form may not be efficiently expanded by the same air pressure, or a third printing form may be expanded too much by the same air pressure causing damages to the third printing form, etc.

Summary of the invention

[0017] The present invention intends to solve at least one of the above mentioned problems. To that effect, the invention relates to an apparatus and a method for mounting and/or demounting printing forms to and/or from a main body, e.g., an adaptor, a base cylinder, and/or a print cylinder. Even more specifically, the present invention relates to an apparatus and a method for mounting and/or demounting an In The Round (ITR) type of printing form to and/or from a cylindrically shaped base adapter.

[0018] According to an embodiment of the current invention, an apparatus for flexographic printing comprises a main body, and the main body comprises: an outer wall with an exterior surface, at least two compartments in the main body, and at least two inlet channels; at least two outlets, wherein each compartment connects to at least one outlet and to at least one inlet channel, such that gas is able to flow from each inlet channel to at least one outlet via at least one compartment, wherein the at least two compartments are separated from each other such that the gas is not able to flow from one compartment to another compartment.

[0019] According to an embodiment of the current invention, the apparatus further comprises at least two connecting elements and a switch unit, wherein each connecting element is configured to connect at least one inlet channel to a source of gas, wherein the switch unit comprises at least one switch, which is configured to control gas supply to each connecting element.

[0020] According to an embodiment of the current invention, the connecting elements are configured to be mounted to and/or demounted from the main body, and/or the switch unit is configured to be connected to or disconnected from the connecting elements, the source, and/or the inlet channels.

[0021] According to an embodiment of the current invention, the switch unit is configured for: switching on a connection to enable supply of gas from the source to at last one outlet via at least one inlet channel and at least one compartment, preferably, adjusting gas pressure while a connection is switched on, and switching off the connection to stop the gas supply to the at least one outlet.

[0022] According to an embodiment of the current invention, the apparatus further comprises at least one printing form, and the at least one printing form is arranged to be shiftable on the exterior surface of the outer wall in a tight fit manner.

[0023] According to an embodiment of the current invention, the at least one printing form is an elastomeric and/or polymeric printing form and is made of rubber, and/or photopolymer.

[0024] According to an embodiment of the current invention, each inlet channel is suitable for gas supply from at least one connecting element, and/or at least one ring and at least one groove are located at a side of the main body, and the at least one ring and the at least one groove are suitable for creating an gas pocket when mounting a printing form from the side of the main body.

[0025] According to an embodiment of the current invention, the main body has a cylinder shape, and the main body comprises at least one of a print cylinder, an adapter, an adapter mounted on a printer cylinder, and an adapter mounted onto a press mandrel.

[0026] According to an embodiment of the current invention, the outlets are through-holes, and walls forming the at least two compartments are walls inside the main body, and/or multiple through- holes connect to a compartment and the through-holes are evenly located on a circle on the exterior surface of the main body, which circle is parallel to a circumference of the main body. [0027] According to an embodiment of the current invention, the main body further comprising at least two tubes, wherein each of the tube is connected to at least one inlet channel, each tube comprises a compartment part, each of the at least two compartments is formed by a compartment part of a tube, and each compartment part comprises at least one outlet.

[0028] According to an embodiment of the current invention, the tubes locate in grooves of the main body, and the tubes do not extend from the exterior surface of the main body.

[0029] According to an embodiment of the current invention, a sheet layer covers the whole exterior surface of the main body or pieces of sheet layers cover the grooves of the main body, and wherein multiple outlets on the sheet layer or the pieces of sheet layers match to the outlets on the tubes.

[0030] According to an embodiment of the current invention, a method for forming an apparatus, comprises the following actions:

a. providing an apparatus comprising a main body, the main body comprising:

i. an outer wall with an exterior surface,

ii. at least two compartments in the main body, and

iii. at least two inlet channels;

iv. at least two outlets,

wherein each compartment connects to at least one outlet and at least one inlet channel, such that gas is able to flow from each inlet channel to at least one outlet via at least one compartment, wherein the at least two compartments are separated from each other such that the gas is not able to exchange between the at least two compartments;

b. moving a first printing form over the main body and supplying gas to at least one outlet via at least one inlet channel and at least one compartment;

c. expanding the first printing form by the gas flowing from the at least one outlet;

d. moving the first printing form to a first position; and

e. discontinuing supplying gas to outlets that are covered by the first printing form such as to retain the first printing form in a tight fit connection on the main body in the first position.

[0031] According to an embodiment of the current invention, the method further comprises before step a, mounting connecting elements and/or a switch unit on the main body such that each connecting element is connected to at least one inlet channel, and/or the switch unit comprises at least one switch, which is configured for controlling gas supply from a source to each connecting element.

[0032] According to an embodiment of the current invention, the method further comprises the following steps while discontinuing supplying gas to through-holes that are covered by any printing form retaining on the main body:

f. moving a further printing form from a set of printing forms over the main body and supplying gas to at least one outlet that is not covered by any retained printing form, via at least one inlet and at least one compartment;

g. expanding the further printing form by the gas from the at least one outlet that is not covered by any printing form retaining on the main body; h. moving the further printing form to a further position on the external surface;

i. discontinuing supplying gas to outlets that are covered by the further printing form such as to retain the further printing form in a tight fit connection on the main body in the further position; and

j. repeating steps f to i until all printing forms of said set of printing forms are mounted to the main body.

[0033] According to an embodiment of the current invention, when a printing form retains on the main body, the method further comprises demounting the printing form by the following steps: k. supplying gas to at least one outlet that is covered by the printing form to be demounted;

L. expanding the printing form to be demounted by the supplied gas; and

m. moving the printing form to be demounted from the main body.

[0034] According to an embodiment of the current invention, the moving of the printing form comprises at least one of: axially and/or rotationally moving the printing form; and/or axially and/or rotationally moving the main body; and/or contacting the printing form with a push sleeve and moving the printing form by the push sleeve.

Brief description of the drawings

[0035] The present invention will be discussed in more detail below, with reference to the attached drawings, in which:

[0036] Fig. 1 is a diagram showing a typical flexographic printing process and/or apparatus.

[0037] Fig. 2 is a cross sectional diagram showing a known mounting process of a printing form on a print cylinder by means of air cushions.

[0038] Fig. 3 is a perspective view of an embodiment of the present invention.

[0039] Fig. 4 is a diagram of an embodiment of the present invention with a cross sectional view.

[0040] Fig. 5 is a diagram of an embodiment of the present invention with a transparent view.

[0041] Fig. 6 is a diagram of an embodiment of the present invention with a cross sectional view along the cross section line VI-VI in fig. 4.

[0042] Fig. 7A is a perspective view of another embodiment of the present invention. Fig.s 7B, 7C, 7D, and 7E, respectively, are enlarged views of the embodiment of Fig. 7 A within the circles VIIB, VIIC, VIID, and VIIE, respectively.

Description of embodiments

[0043] Embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. However, the embodiments of the present disclosure are not limited to the specific embodiments and should be construed as including all modifications, changes, equivalent devices and methods, and/or alternative embodiments of the present disclosure.

[0044] The terms“have,”“may have,”“include,” and“may include” as used herein indicate the presence of corresponding features (for example, elements such as numerical values, functions, operations, or parts), and do not preclude the presence of additional features.

[0045] The terms“A or B,”“at least one of A or/and B,” or“one or more of A or/and B" as used herein include all possible combinations of items enumerated with them. For example,“A or B,”“at least one of A and B,” or“at least one of A or B” means (1) including at least one A, (2) including at least one B, or (3) including both at least one A and at least one B.

[0046] The terms such as “first” and “second” as used herein may modify various elements regardless of an order and/or importance of the corresponding elements, and do not limit the corresponding elements. These terms may be used for the purpose of distinguishing one element from another element. For example, a first printing form and a second printing form may indicate different printing forms regardless of the order or importance. For example, a first element may be referred to as a second element without departing from the scope the present invention, and similarly, a second element may be referred to as a first element.

[0047] It will be understood that, when an element (for example, a first element) is“(operatively or communicatively) coupled with/to” or“connected to” another element (for example, a second element), the element may be directly coupled with/to another element, and there may be an intervening element (for example, a third element) between the element and another element. To the contrary, it will be understood that, when an element (for example, a first element) is“directly coupled with/to” or“directly connected to” another element (for example, a second element), there is no intervening element (for example, a third element) between the element and another element.

[0048] The expression“configured to (or set to)” as used herein may be used interchangeably with “suitable for,”“having the capacity to,”“designed to,”“ adapted to,”“made to,” or“capable of” according to a context. The term“configured to (set to)” does not necessarily mean“specifically designed to" in a hardware level. Instead, the expression“apparatus configured to...” may mean that the apparatus is“capable of...” along with other devices or parts in a certain context.

[0049] The terms used in describing the various embodiments of the present disclosure are for the purpose of describing particular embodiments and are not intended to limit the present disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. All of the terms used herein including technical or scientific terms have the same meanings as those generally understood by an ordinary skilled person in the related art unless they are defined otherwise. The terms defined in a generally used dictionary should be interpreted as having the same or similar meanings as the contextual meanings of the relevant technology and should not be interpreted as having ideal or exaggerated meanings unless they are clearly defined herein. According to circumstances, even the terms defined in this disclosure should not be interpreted as excluding the embodiments of the present disclosure.

[0050] According to an embodiment of the present invention, as shown in Fig. 3, an apparatus 310 for flexographic printing comprises a main body 320, at least two compartments (not shown in Fig. 3; but for example, 410-413 in Fig. 4), at least two connecting elements or connectors e.g., 330a, 330b and 330c, and a switch unit 340. The connectors, e.g., 330a, 330b and 330c, are arranged for transporting air. They may be flexible or non-flexible and may be of any suitable material including metal, rubber or plastic. They can have the form of a pipe or a hose. The apparatus 310 may further comprise an air source 390, an air source connector 391 , or a controller 392, e.g., a smart phone or a computer, and communication means 393. The communication means 393 may be based on any communication technologies, e.g., wire and/or wireless communications. Some parts in fig. 3 may be omitted, for example the collectors 330a, 330b, 330c, the switch unit 340, the controller 392 and/or the communication means 393.

[0051] The main body 320 may be a print cylinder, an adapter, an adapter mounted onto a print cylinder, or an adapter mounted onto a press mandrel, but not limited to these examples. The main body 320 may be in a cylindrically shape with an outer wall parallel to the direction of a central axis 31 1 of the cylindrically shaped main body 320. The exterior surface of the outer wall of the main body 320 (hereafter also referred as the cylinder surface, or simply the surface) comprises at least two outlets, e.g., 321 and 322, which may be evenly or unevenly distributed on the cylinder surface. The outlets are configured to enable gas to flow through, which may be formed by openings, through-holes, or any other suitable manner. In this document, the terms“outlet” and“through-hole” are interchangeably used, unless explicitly distinguished. The at least two compartments are located inside the main body and each of the at least two compartments connects to at least one outlet in the outer wall.

[0052] The main body 320 will be described in more detail with the example in Figs. 4, 5, and 6.

[0053] Fig. 4 is a diagram of an embodiment of the present invention with a cross sectional view along the axial direction 31 1 . The main body 400 may comprise two spindle parts 480 and 481 and a main body similar to 320 in Fig. 3. The spindle parts 480 and 481 may be used to enable main body 400 to spin around the axial line 31 1 . These two spindle parts 480 and 481 may be mounted to the main body 320 to form main body 400, or demounted from main body 400 to become the main body 320. The demounting of the spindle parts 480 and 481 may be convenient when the connecting elements, e.g., 330a, 330b and 330c, are being connected to the main body for mounting printing forms. The mounting of printing forms with the apparatus will be described later.

[0054] The main body 400 comprises an outer wall 470 which surrounds multiple compartments, e.g., 410, 41 1 , 412, and 413. The compartments 410, 41 1 , 412, 413 are separated by respective inner walls, e.g., 471 . The outer wall 470 comprises outlets 430, 431 , 432 and 433, respectively, at least one outlet per compartment 410, 41 1 , 412 or 413. Compartment 410 is connected to an inlet channel 420 (or called inlet or channel hereafter), via which air, supplied from the air source 390 via the switch unit 340 and/or connection elements, e.g., 330a, 330b and/or 330c, may flow into compartment 410, and, then, flow out of outlet 430. Similar, compartment 41 1 is connected to an inlet channel 421 , via which air, supplied from the air source 390 via the switch unit 340 and/or connection elements, e.g., 330a, 330b and/or 330c, may flow into the compartment 41 1 , and, then, flow out of outlet 431 . Differently, compartment 412 is connected to an inlet channel 422, via which air may flow into both compartments 412 and 413, and, then, flow out of outlets 432 and 433. In the example shown in Fig. 4, there is a outlet 440 in the inner wall 472 between the compartments 412 and 413 which functions as an inlet channel for compartment 413. Because compartments 412 and 413 may have air exchange, compartments 412 and 413 may be considered as one compartment. In the example shown in Fig. 4, compartments 410, 41 1 and 412 are not connected to each other, which means they are separate compartments such that air in one compartment may not flow to another compartment. I.e., there may be no air exchange between compartments 410, 41 1 and 412. [0055] According to any of the previous embodiments, there may be a groove 360 and/or a ring 350 on one end of main body 320 as shown in Fig. 3. The ring 350 may be located at one end of the main body 320 and the groove 360 may be located between the ring 350 and the rest of the main body 320. Furthermore, one side of the ring 350 may be bevelled, such that the circumference of the ring 350 on the bevelled side may be shorter than the circumference of the other side of the ring 350. This is for easy mounting when a printing form is being mounted to the main body via the ring 350. The groove 360 may comprise one or more outlets to create an air cushion between a printing form and the main body 320 while mounting the printing form. Or, there may be no outlet in the groove 360, and only the outlets 321 , 322 on the main body 320 are used to create an air cushion. The main body 400 shown in Figs. 4, 5 and 6 may comprise a ring 460 and groove 450 too, which are similar to the ring 350 and groove 360 in Fig. 3.

[0056] It is observed that Fig. 4 shows one possible embodiment. There may be any other number of distinct compartments that are connected or not connected to one another.

[0057] According to an embodiment of the present invention, each of the inlet channels 420, 421 and 422 may connect to one or more connecting elements, e.g., 330a, 330b, 330c, to enable air supplies from the air source 390 (now shown in Fig 4). For example, the connecting elements e.g., 330a, 330b, 330c, may be fixedly attached to the inlet channels 420, 421 , 422, e.g., by bolts, or directly plugged into the inlet channels 420, 421 , 422. Of course, other connecting methods are also possible.

[0058] Fig. 5 is a perspective diagram of the embodiment of Fig. 4 of the present invention with a partly transparent view.

[0059] In the transparent view of fig. 5, more outlets are visible besides outlets 430, 431 , 432. An inlet channel, e.g., 420, 421 or 422, may be connected to a compartment, e.g., 410, 41 1 or 412 in any direction/position. For example, inlet channel 420 connects to compartment 410 on the right side and inlet channel 421 connects to compartment 41 1 also on the right side, but inlet channel 422 connects to compartment 412 from another direction/position.

[0060] Fig. 6 is a diagram of an embodiment of the present invention with a section view along the cut line VI-VI shown in fig. 4.

[0061] According to an embodiment of the present invention, the at least two compartments, e.g., 410, 41 1 , 412, are located inside the main body 400 and each of the at least two compartments 410, 41 1 , 412, connects to at least one outlet, e.g., 430, 431 , 432 on the surface of the outer wall 470.

[0062] Furthermore, the connections between a compartment, e.g., 410 and outlets, e.g., 430 may have different design choices. For example, the connections may be designed in such a way that one compartment, e.g., 410, connects to one or more outlets, e.g., 430, or multiple compartments connect to the same outlet or the same group of outlets (not shown in the figures). Or, the connections may be designed to dynamically change from one time point to another time point. Additionally, the changing of the dynamical connections may be manually controlled by an operator, and/or automatically controlled by an application or software on the controller 392 via the communication means 393. [0063] Furthermore, the controller 392 may control the air source 390 with an application or software to enable different air pressure from the air source 390.

[0064] Preferably, the outlets, e.g., 430, 431 and 432, and compartments e.g., 410, 41 1 , 412, may be suitable for a flow of air. All over the present document, air is used as an example, but the present invention is not limited to that example.

[0065] Preferably, the outlets, e.g., 430a, 430b, connected to one compartment, e.g., 410, may be evenly distributed on a single circle line on the exterior surface of the outer wall 470, and the circle defines a plane perpendicular to the central axis 31 1 of the main body 400, as shown in Fig. 5. The outlets, e.g., 430a, 430b, on one circle may be located on even angularly distributed positions. Of course the locations of outlets, e.g., 430a, 430b, are not limited to this example. For example, the outlets, e.g., 430a, 430b, may be randomly distributed on the exterior surface of the outer wall 470.

[0066] According to an embodiment of the present invention, a connector, e.g., 330a, may provide at least one connection between an air source 390 and a compartment, e.g., 410. The connection is suitable for suppling air from the source 390 to a compartment, e.g., 410, and eventually, the air flows out of the outlets, e.g., 430, that are connected to the compartment, e.g., 410. For example, air from the air source 390 may flow through connector 330a, reach compartment 410, and finally flow out of outlets 430, 430a and 430b that are connected to compartment 410. The connectors 330a, 330b, 330c may be made of any proper material and made into any shape such that a sufficient amount of air flows to a compartment at a certain supply pressure.

[0067] Furthermore, a connector, e.g., 330a, may be designed in such a way that the connector 330a may be used to supply air to multiple compartments, e.g., 410 and 41 1 , and/or multiple connectors, e.g., 330a and 330b, may be used to supply air to one compartment, e.g., 410. The connections between compartments, e.g., 410, 41 1 , 412, and connectors, e.g., 330a, 330b, may be dynamically changed. For example, at a first time instance, connectors 330a and 330b connect to compartment 410, and connector 330c connects to compartments 41 1 and 412. Then at a second time instance, connector 330c connects to compartment 410, and connectors 330a and 330b, connect to compartments 411 and 412. Of course, this example does not limit the present invention, and any other connection designs are possible. The dynamic connections may be controlled manually by a person, and/or automatically by an application or software by a controller 392 via communication means 393.

[0068] According to an embodiment of the present invention, the switch unit 340 may comprise at least one switch 341 . A switch 341 is configured to control the supply air pressure, when the air from the source 390 flows to one or more connectors, e.g., 330a and/or 330b. For example, by operating the switch unit 340, the supplied air pressure may be switched off entirely, or the supplied air pressure may be switched to a maximal supplied air pressure, or the air supply may be switched to any supplied air pressure in-between zero and the maximal pressure. More specifically, the switch unit 340 is suitable for switching on a connection, between the source 390 and a connector 330a, 330b or 330c, to enable supply of air from the source 390 to a outlet430, 431 and/or 432 via a connector 330a, 330b or 330c and a compartment 410, 41 1 or 412, adjusting a supplied air pressure when the connection is switched on, and switching off the connection to stop/discontinue the air supply for the outlet430, 431 and/or 432.

[0069] Furthermore, switch 341 (of the switch unit 340) may control the supplied air pressure for different connectors 330a, 330b, 330c, at different time instances, and/or different states of switch 341 may control the supplied air pressure for different connectors 330a, 330b, 330c. For example, when switch 341 is in a first state at a first time instance, the supplied air pressure to connector 330a is switched to maximal pressure, the supplied air pressure to connector 330b is switched to 50% of the maximal pressure, and the supplied air pressure to connectors 330c and other connectors is switched off. Then, when switch 341 changes to a second state at a second time instance, the supplied air pressure to connector 330a is switched to 50% of the maximal pressure, the supplied air pressure to connector 330b is switched off, and the supplied air pressure to connectors 330c and other connectors is turned on to maximal pressure. This example does not limit the present invention, and any other combinations are possible.

[0070] Furthermore, when there are multiple switches, e.g., 341 and 342, combinations of the states of the multiple switches, e.g., 341 and 342, may be used to determine the supplied air pressure to different connectors e.g., 330a, 330b, and/or 330c. More specifically, air supply to one or more outlets, e.g., 430, 431 and/or 432, (via at least one connector, e.g., 330a, 330b, and/or 330c, and at least one compartment, e.g., 410, 41 1 , and/or 412) may be controlled by multiple switches, e.g., 341 and 342, at the same time. As an example, each switch may turn on/off the air supply to a outletindividually. As another example, a combination of states of the switches, e.g., 341 and 342, may be used to determine the air supply to all the outlets, e.g., 430, 431 and 432. Of course, these examples do not limit the present invention and any suitable switch designs may be comprised by the present invention.

[0071] According to an embodiment of the present invention, via controlling the supplied air pressure by the switch unit 340, the air supplied to an individual compartment, e.g., 410, 41 1 , or 412, (eventually to one or more outlets, e.g., 430, 431 and/or 432) or a group of compartments, e.g., 410 and 41 1 , (eventually to one or more outlets, e.g., 430 and 431) may be different at one time instance. For example, at one time instance, there is air flowing to outlet430 but there is no air flowing to outlet 431 or another group of outlets 431 and 432. This may be achieved by changing the states of one or more switches, e.g., 341 and/or 342 in the switch unit 340. For example, when there is one switch 341 , a first state of the switch 341 provides 20% of the maximal supplied air pressure to outlet430 and no air supply to outlets 431 and 432; but a second state of the switch 341 provides maximal air supply to outlet 431 , and no air supply to outlets 430 and 432.

[0072] According to an embodiment of the present invention, the connectors 330a, 330b, 330c and/or the switch unit 340 may be mounted to the main body 320/400 and demounted from main body 320/400. Preferably, the connectors 330a, 330b, 330c and the switch unit 340 may be separated from each other. Preferably, the connectors 330a, 330b, 330c and the switch unit 340 may be arranged such that they can be separated from the air source 390.

[0073] In one example, the switch unit 340 can be combined to the connectors 330a, 330b, 330c, or the connectors 330a, 330b, 330c can be separated from the switch unit 340. More specifically, there may be joints on the switch unit 340 such that connectors 330a, 330b, 330c may be easily plugged on or plugged off.

[0074] In another example, either when the switch unit 340 and the connectors 330a, 330b, 330c are combined together, or when they are separated from each other, a connector 330a, 330b, or 330c may be mounted to or demounted from the main body 320/400 and connect to or disconnect from at least one compartment 410, 41 1 and/or 412 via inlet channels 420, 421 , and/or 422. In an example, connector 330a may be mounted to the main body 320/400 via a joint on the main body 320/400 by directly plugging the connector, e.g., 330a, on the joint, or demounted from the main body 320/400 by directly unplugging from the joint. In another example, extra mounting elements may be used while mounting the connector 330a, 330b, and/or 330c to the main body 320/400, e.g., a collecting element 370 and bolts 380 as shown in fig. 3. Such examples of mounting and demounting of the connectors 330a, 330b, 330c with the main body do not limit the present invention, and any other designs may be used in the present invention.

[0075] According to any embodiment of the present invention, the switch unit 340 may be omitted. In this case, the supplied air pressure may be controlled at the air source 390 side, either manually, or automatically by controller 392 via communication means 393. Or, the switch unit 340 may be incorporated directly to the inlet channels, 420, 421 , 422, of main body, e.g., 320/400, (i.e., omitting the connectors, e.g., 330a, 330b, 330c, between the switch unit 340 and inlet channels, e.g., 420, 421 and 422). Or, the switch unit 340 may be incorporated directly to the air source 390, (i.e., omitting the air source connector 391 between the air source 390 and the switch unit 340). Or, both the connectors, e.g., 330a, 330b and 330c, and the switch unit 340 may be omitted by directly connecting the air source 390 to the inlet channels 420, 421 and 422. According to any embodiment of the present application, the supplied air pressure out of the air source 390 may be adjusted manually, or automatically by controller 392 via communication means 393.

[0076] According to any of the previous embodiments, there may be more than one switch unit for a main body and each switch unit may comprise at least one switch.

[0077] According to any of the previous embodiments, different connectors of a main body may connect to different air sources (when there are several air sources). For example, a first connector may be connected to a first air source, but a second connector may be connected a second air source. These types of obvious design choices do not limit the present invention.

[0078] According to any of the previous embodiments, there may be more than one connector from one air source to one inlet channel of the main body. In one example, a backup connector may be used together with a main connector to improve the reliability of the apparatus. In another example, the air supply may be divided by more than one connector to a outlet, and by switching on/off one of the connectors, the supplied air pressure to the outlet may be adjusted. In a third example, a inlet channel may comprise multiple openings and each opening is connected to a connector. These types of obvious design choices of the connectors do not limit the present invention. [0079] According to any of the previous and later embodiments, the air supply may be replaced with any other suitable gas supply, for example, nitrogen. In this application, the term “air” is interchangeable with the term“gas”. [0080] In the previous embodiments, any of the features can be combined in any way to form an apparatus. For example, any possible features regarding the (combined) main body may be combined with any possible features regarding a single main body (e.g., 320/400), the switch unit, connectors, air source, the groove, and/or the ring. [0081] According to any ofthe embodiment of the present invention, a compartment may be in any shape. For example, a compartment may have a cylinder shape, a ball shape, a ring shape, etc. Especially, the compartment may have a tube or channel shape arranged such that it directly connects one inlet channel to one or more outlets.

[0082] Fig. 7A is a perspective view of another embodiment of the present invention, in which the inlet channels and compartments are implemented together by tubes. The main body 710 comprises a groove 760 and a ring 750 (cf. Fig. 7B) and the groove 760 and the ring 750 in Fig. 7B are the same as the groove 360 and the ring 350 in Fig. 3A.

[0083] The apparatus further comprises inlet channels 701 -707 (Fig. 7E) and compartments parts 721 -727. Each of the inlet channels 701 to 707 may be connected to a separate connecting element for gas supply, or two or more of the inlet channels 701 -707 may be connected to the same connecting element for gas supply. There may be one or more valves (i.e., switch units), e.g., valves 791 , 792 and 793 shown in Fig. 7E, which can be used to control/adjust the air supplies to each inlet channel 701 to 707.

[0084] In the embodiment of Fig. 7A-7E, each compartment part is implemented as a compartment tube 721 -727. Each compartment tube 721 -727 is attached/connected to one inlet channel 701 - 707. Here, each compartment tube 721 -727 is implemented as a first straight portion arranged in a groove of the main body 710 in the axial direction and a second, ring shaped portion arranged in a circumferential groove of the main body 710. The second portion may be open ring shaped (as shown in Fig. 7A) or closed ring shaped (not shown). Preferably, each inlet channel 701 -707 forms one single tube with one compartment part 721 -727. Preferably, the tubes do not extend from the exterior surface of the main body 710. They may be located inside the main body 710.

[0085] Outlets are formed by one or more holes in each second portion of the compartment tube 721 -727, e.g., holes 740 in the compartment tube 724. Gas may flow from the inlet channels and compartment tubes out of these holes. When the compartment tubes 721 -727 are inside the main body 710, the holes in the compartment tubes 721 -727 are connected with through-holes/outlets on the exterior surface of the main body 710, via which gas from inlet channels 701 -707 may flow to the exterior surface of the main body 710.

[0086] When there are more holes per second portion of the compartment tube 721 -727, they may be evenly distributed along the circumference of the main body 710. [0087] When the compartment tubes 721 -727 are located in grooves on the exterior surface of the main body 710 as show in Fig. 7A, a sheet layer may be placed to cover the main body to form a smooth exterior surface like the exterior surface of the main body 320 shown in Fig. 3, in which case the sheet layer comprises through-holes/outlets located such as to match the holes in the compartment tubes 721 -727. Or, only the groove parts may be covered by pieces of sheet layers to form a smooth exterior surface like the exterior surface of the main body 320 shown in Fig. 3, in which case the sheet layers comprise through-holes/outlets matching the holes in the compartment tubes 721 -727.

[0088] There may be several above mentioned sheet layers on top of each other. The sheet layers may be made from the same material as the main body.

[0089] With similar shapes of inlet channels 701 -707 and compartment tubes 721 -727 as shown in Fig. 7A, inlet channels 701 -707 and compartment tubes 721 -727 may be formed inside the main body 710 as a whole, i.e. , without separate tubes. For example, the main body 710 may be drilled and form the inlet channels 701 -707, compartment tubes 721 -727 and through holes having the same structure as in Fig. 7A. In this case, no extra sheet layer may be needed on the surface of the main body 710.

[0090] Other embodiments may result from a combination of different features in Figs. 3, 3A, 4, 5, 6, 7A-7E and any other alternatives presented in this document, e.g., the arrangement of the through-holes/outlets, the connecting elements, the compartments, etc. Thus, these specific embodiments should not limit the current invention, whenever a combination of features in these specific embodiments and/or presented alternatives are obvious to a person skilled in the art.

[0091] According to any of the previous embodiments, the apparatus may comprise one or more printing forms. The at least one printing form may be mounted to or demounted from a main body 320/400.

[0092] According to an embodiment of the present invention, a first printing form may be mounted to a main body. The mounting of the first printing form may comprise the following steps.

a. providing an apparatus comprising a main body, the main body comprising:

i. an outer wall with an exterior surface,

ii. at least two compartments in the main body, and

iii. at least two inlet channels;

iv. at least two outlets,

wherein each compartment connects to at least one outlet and at least one inlet channel, such that gas is able to flow from each inlet channel to at least one outlet via at least one compartment, wherein the at least two compartments are separated from each other such that the gas is not able to exchange between the at least two compartments;

b. moving a first printing form over the main body and supplying gas to at least one outlet via at least one inlet channel and at least one compartment;

c. expanding the first printing form by the gas flowing from the at least one outlet;

d. moving the first printing form to a first position; and e. discontinuing supplying gas to outlets that are covered by the first printing form such as to retain the first printing form in a tight fit connection on the main body in the first position.

[0093] Normally, the positioning/moving of the printing form will be done manually, or automatically. The right fit connection of the first printing form on the main body ensures that the the first printing form does not shift (or move) relatively to the main body when printing.

[0094] According to an embodiment of the present invention, the main body in step a may be any main body described in any of the previous embodiments or a combination of any of them.

[0095] According to an embodiment of the present invention, before step b, air supply to all the outlets (e.g., via at least one inlet channel and at least one compartment) of the main body may be switched off. In step b, a connection for air supply to a outlet or a group of outlets may be switched on. The air supplies may be adjusted to a certain pressure to enable sufficient expanding of the first printing form for easy mounting but not to damage the first printing form. The mounting of the first printing form may start from the ring 350 side of the main body and the first printing form may be axially mounted to the main body. The switching on of the air supply may be before or after putting the first printing form partly on the main body.

[0096] Furthermore, when a part of the first printing form covers a outlet on the groove 360 (or on the exterior surface of the outer wall), an air cushion is created by the air from the outlet between the first printing form and the main body. Because of the air cushion, the first printing form may be moved easily axially and/or rotationally on the main body. Then, the first printing form may be positioned/moved to a predefined position on the main body. This predefined position may be determined to synchronize all printing forms in a sequence during a flexographic printing process, for example when different printing forms are with different colors or printing patterns. After the first printing form is positioned correctly, the air supply to the covered outlet(s) (via corresponding connector(s) and compartment(s)) by the first printing form may be switched off/discontinued by the switch unit. When all the outlets covered by the first printing form are switched off, the first printing form is not expanded anymore but contracts and retains on the main body. When the first printing form retains on the main body, the first printing form may be tightly retained such that the first printing form may not be relatively moved axially and/or rotationally to the main body whiling printing.

[0097] According to any embodiment of the present invention, the switch unit may be omitted. For example, the switching off of the air supply may be achieved by plugging off the air source from the connector or by plugging a connector off the inlet channel. All these obvious choices do not limit the present invention.

[0098] Furthermore, if the retained position of the first printing form is not correct according to the predefined position, the air supplies to the outlets covered by the first printing form or all the air supplies to all the outlets of the main body, may be switched on by the switch unit to provide a proper supplied air pressure. Then an air cushion is created for adjusting the position of the first printing form. After the position of the first printing form is adjusted (i.e., re-adjusted) to the predefined position or another position, the air supply to all the outlets covered by the first printing form may be switched off again to retain the first printing from on the main body. This re-adjusting process may be repeated multiple times until the first printing form is correctly positioned/retained on the main body.

[0099] Furthermore, after/while the first printing is retained on the main body, the air supplies to the outlets that are not covered by the first printing form (if there are any) may be switched off as well. Or the rest of the outlets may be maintained switched on for mounting a next printing form.

[00100] Furthermore, during the mounting of the first printing form, the supplied air pressure may be adjusted. For an example, when switching off the air supplies to the outlets that are covered by the first printing form, the supplied air pressure supply may be reduced little by little until there is no air supply. It is to avoid a sudden change of the air supply, which may move the first printing form from its desired position. In another example, when switching off the air supplies to the outlets that are covered by the first printing form, the air supplies may not be entirely switched off, instead the supplied air pressure is reduced to a predefined value or values.

[00101] According to an embodiment of the present invention, while moving the first printing form axially and/or rotationally on the main body, the air supplies to the outlets may be adjusted to enable easy mounting. In an example, at the same time instance, strong air supplies (e.g., supplied air pressure higher than a predefined value) to outlets located at a certain part of the main body may be necessary, and weak air supplies (e.g., supplied air pressure lower than the same or another defined value) to the outlets located at other parts of the main body may be necessary. This difference in supplied air pressure for different outlets may be required because of different materials and/or structures of the main body in these parts, or different material and/or structure of the first printing form. In a third example, while moving the first printing form axially and/or rotationally on the main body, if the first printing form moved passed a outlet and the outlet is not covered by the first printing form anymore, the air supply to this outlet may be switched off. I.e., while moving the first printing form, only the air supplies covered by the first printing form is switched on and all or a part of the air supplies to other outlets (not covered at the moment) are switched off. By this means, less energy and resource are consumed because only a part of the outlets are supplied with air at a time instance during the mounting of the first printing form.

[00102] According to any previous embodiments of the present invention, while moving the first printing form, the printing form may be axially and/or rotationally moved, and/or the main body may be axially and/or rotationally moved. And/or, a hard sleeve may be used to push the first printing form to the pre-defined position.

[00103] According to an embodiment of the present invention, a second printing form may be mounted to the main body after the first printing form has been mounted. The mounting of the second printing form may comprise the following steps, during which steps all the air supplies, to the outlets that are covered by the first printing form (and any other already retained printing forms on the main body), are switched off/discontinued:

f. moving a further printing form from a set of printing forms over the main body and supplying gas to at least one outlet that is not covered by any retained printing form, via at least one inlet and at least one compartment; g. expanding the further printing form by the gas from the at least one outlet that is not covered by any printing form retaining on the main body;

h. moving the further printing form to a further position on the external surface;

i. discontinuing supplying gas to outlets that are covered by the further printing form such as to retain the further printing form in a tight fit connection on the main body in the further position; and

j. repeating steps f to i until all printing forms of said set of printing forms are mounted to the main body.

[00104] More specifically, all the air supplies to the outlets that are covered by the first printing form (or any other printing forms that retain on the main body) should be kept switched off during the whole procedure of mounting the second printing form (from step f to step j). By this means, the position of the first printing form (and any other printing form that already retain on the main body) may not be changed and may be kept to the predefined position on the main body.

[00105] Furthermore, except keeping switching off the air supplies to the outlets that are covered by the first printing form, the mounting of the second printing form is similar as the mounting of the first printing form. For example, the air supply to at least one outlet, which is not kept switching off in step e, is switched on with certain supplied air pressure. For example, the supplied air pressure may be a proper supplied air pressure that is able to sufficiently expand the second printing form to be moved easily on the main body but not to damage the second printing form. This proper supplied air pressure for the second printing form may be different from the proper supplied air pressure for the first printing form because printing forms may be different in materials and/or structures.

[00106] Furthermore, the second printing form may be put on the main body on one side of the main body, for example, via the ring 350 and the groove 360 side. The second printing form is positioned to a predefined position which is different from the predefined position of the first printing form. After the second printing form is positioned correctly, the air supply is switched off for outlets that are covered by the second printing form. The second printing form then retains to the main body, e.g., is tightly retained after all the air supplies to the covered outlets are switched off. The air supplies to the outlets that are not covered by the first printing form and the second printing form may be maintained on or may be switched off.

[00107] Furthermore, a re-adjusting procedure for the second printing form, which is similar as the re-adjusting procedure of the first printing form, may be performed repeatedly until the second printing form is correctly positioned.

[00108] Furthermore, the retained first printing form and the retained second printing form may be located side by side on the main body with or without a gap in between, or overlapping with each other.

[00109] According to an embodiment of the present invention, as indicated in step j, a third, fourth, or even more printing forms may be mounted to the main body with the steps from e to i. The detailed procedure for mounting these printing forms will not be repeated here, but the principles are the same. [00110]According to an embodiment of the present invention, a printing form that retains on the main body may be removed/demounted from the main body. The demounting process may comprise the following steps:

k. supplying gas to at least one outlet that is covered by the printing form to be demounted;

L. expanding the printing form to be demounted by the supplied gas; and

m. moving the printing form to be demounted from the main body.

[00111] More specifically, the demounting procedure may be understood as a reversed mounting procedure, which is presented previously. For example, when starting demounting a printing form that retains on the main body, the air supplies to the outlets that is covered by the printing form may be switched on to a proper supplied air pressure. Then, an air cushion may be formed between the printing form and the main body, which may enable easy moving of the printing form on the main body axially and/or rotationally. Then, the printing form may be removed from the printing form from one side of the main body, e.g., maybe from the ring 350 and groove 360 side or the other side. The supplied air pressure to different outlets may be different, as long as the printing form is able to be expanded efficiently (and/or not damaged) to be easily removed from the main body. For example, all the air supplies to all the outlets may be switched on to certain supplied air pressure during the whole procedure of the demounting. In another example, while moving the printing form, only air supplies to the outlets that are covered by the printing form are switched on, and all air supplies to the non-covered outlets (by the to be demounted printing form) are switched off. By this means energy and resources are used more efficiently. Further, in this way, the printing forms, retaining on the main body which are not intended to be removed, does not move from their desired positions. Of course, these examples are merely some demonstrations of the present invention, which do not limit the present invention.

[00112] According to an embodiment of the present invention, as in the mounting procedure, a hard sleeve may be used to push the printing form in a demounting procedure.

[00113] According to an embodiment of the present invention, when there are multiple retained printing forms on the main body, the printing forms may be demounted one by one by a procedure similar to the previous discussed demounting procedure.

[00114] According to an embodiment of the present invention, when there are multiple retained printing forms on the main body, a first group of the printing forms retained on the main body may be demounted and changed to a second group of new printing forms, while the other printing forms stay retained on the main body. In this case, while demounting the first group of printing forms and/or mounting the second group of new printing forms, the air supplies to the outlets covered by the other printing forms may be kept switching off, in order to avoid undesired shift/movements. Furthermore, the axial lengths and predefined positions of the newly mounted second group of printing forms may be different from the demounted (changed) first group of printing forms.

[00115] According to any of the previous embodiments, a switch and/or switch unit 340may be implemented electronically that is controlled by an electric device or controller 392, e.g., a computer or a smart phone 392 via communication means 393. The switch unit may be controlled by a program or software executed on the electronic device or controller 392. Furthermore, sensors (e.g., light sensors, cameras, motion sensor, or other sensors) may be used to detect whether a outlet is covered by a printing form and to provide feedback to the executed program or software. In addition, sensors (e.g., light sensors, cameras, motion sensor, or other sensors) and another program or software may be used to locate the positions of the printing forms, e.g., while moving the printing forms. In addition, the moving, mounting and/or demounting of the printing forms may be executed either manually or automatically by a machinery.

[00116] According to any of the previous embodiments, a support sleeve (or more layers of support sleeves) may be mounted to the main body first before mounting printing forms. The mounting of the support sleeve may be via a similar procedure of mounting a printing form as described previously. After the support sleeve is mounted, a printing form may be mounted to the main body on top of the support sleeve. The support sleeve may be used to protect the main body, and/or to protect the printing form, and/or to provide a desired hardness for the printing form while printing, and/or to achieve any other effects.

According to any of the previous embodiment, the present invention/apparatus is fundamentally different from apparatuses known in the art.

[00117] Preferably, the present invention/apparatus may comprise an individual air supply from the inlet channels to different compartments of the main body. By this means, the air supplies to different outlets may be switched on or off independently.

[00118] Preferably, the present invention/apparatus may comprise multiple groups of outlets depending on the total axial length of the main body, allowing printing forms to be mounted with a width as little as e.g., 100 mm to a maximum of e.g., 2,250 mm, whilst at the same time allowing a full width of a printing form to be mounted.

[00119] The ring 350 and groove 360, if applied, may create an air pocket when a printing form is being mounted, which may be crucial for easy mounting of sensitive printing forms without damaging the printing forms.

[00120] Preferably, the surface of the main body may comprise a layer or more layers with different hardness. The different hardness may be necessary to meet specific properties of different ink types. Furthermore, the surface of the main body may comprises non-sticking properties, which may be necessary for easy mounting, positioning and minimizing the damage to the inside surface of the printing forms.

[00121] Preferably, each group of the outlets may have its own or duel unique air supply, which may be directed through a single combined or multiple connectors. The connectors may be formed by manifold supply brackets. The manifold bracket may be unique to each individual main body. Each group of the outlets may comprise multiple outlets, e.g., a number between 4 and 16 outlets depending on the diameter of the main body.

[00122] Preferably, the separated air supply accessory / manifold may be used on any standard mounter proofer machine, which may make the adapter totally universal.

[00123] Preferably, the manifold bracket may have an arc shaped bracket, for example from 10 degree arc through to a 360 degree arc. [00124] Preferably, the present invention provides a method and apparatus for mounting two or more printing forms side by side on a main body. In particular, the method and the apparatus are suitable for mounting two or more cylindrically-shaped printing forms on a main body that is cylindrically-shaped. The main body may be a print cylinder or an adapter sleeve or adapter that mounts onto a print cylinder or a press mandrel or any bridge sleeve for printing.

[00125] According to any of the previous embodiments, printing forms in the present invention are not limited, provided that the printing form may be cylindrically shaped or may become cylindrically- shaped for mounting to the main body. For example, the printing form may comprise a support and a layer of material having a relief structure suitable for relief printing, which may be flexographic printing, letterpress printing or gravure printing using a gravure sleeve.

[00126] According to any of the previous embodiments, the printing form may comprise photopolymer printing forms (precursors) in which a layer of a photopolymer material capable of forming a relief surface suitable for flexographic printing is included on the support. The support for the printing form itself may be cylindrical, or the printing form may be grouped with at least one other structure that is cylindrically-shaped. The cylindrically-shaped support or structure may also be referred to as a sleeve.

[00127] According any of the previous embodiments, the printing form may comprise one or more printing plates mounted onto a cylindrically-shaped support. The printing form may comprise at least one alignment indicator or registration mark for registering a position of the printing form on the main body. The alignment indicator is not limited and may be, for example, any feature on a viewable surface of the printing form, a feature that is a part of the relief surface of the printing form, a feature embedded into or on the printing form, or a scribe mark or other marking on a surface of the printing form.

[00128] According any of the previous embodiments, the printing form may comprise a side edge at each end that may be considered as an alignment indicatorfor positioning the printing form axially on the main body. The printing form may comprise an exterior surface where the alignment indicator may be located, and an interior surface that may be adjacent or in contact with an exterior surface of the main body.

[00129] According any of the previous embodiments, the printing form may be radially expanded by a pressurized air, fluid or powder, and contracting when the pressurized air, fluid or powder is removed.

[00130] According any of the previous embodiments, the printing form may have an axial length, along a central axis around which the printing form rotates. Each printing form mounted to the main body may have an axial length such that a sum of the axial lengths of all the printing forms (being mounted) is less than or equal to an axial length of the main body. A printing form having an axial length that is less than an axial length of the main body may be referred to as a mini sleeve or a multi sleeve. The two or more printing forms may be positioned on the main body such that one or more adjacent side edges of each printing form are neighbouring. Or, the two or more printing forms may be positioned on the main body such that there is a gap between the side edges of adjacent printing forms. [00131]According to an embodiment of the current invention, an apparatus for flexographic printing comprises a main body, and the main body comprises: an outer wall with an exterior surface, at least two compartments in the main body, and at least two inlet channels; at least two outlets, wherein each compartment connects to at least one outlet and to at least one inlet channel, such that gas is able to flow from each inlet channel to at least one outlet via at least one compartment, wherein the at least two compartments are separated from each other such that the gas is not able to flow from one compartment to another compartment.

[00132] According to an embodiment of the current invention, the apparatus further comprises at least two connecting elements and a switch unit, wherein each connecting element is configured to connect at least one inlet channel to a source of gas, wherein the switch unit comprises at least one switch, which is configured to control gas supply to each connecting element.

[00133] According to an embodiment of the current invention, the connecting elements are configured to be mounted to and/or demounted from the main body, and/or the switch unit is configured to be connected to or disconnected from the connecting elements, the source, and/or the inlet channels.

[00134] According to an embodiment of the current invention, the switch unit is configured for: switching on a connection to enable supply of gas from the source to at last one outlet via at least one inlet channel and at least one compartment, preferably, adjusting gas pressure while a connection is switched on, and switching off the connection to stop the gas supply to the at least one outlet.

[00135] According to an embodiment of the current invention, the apparatus further comprises at least one printing form, and the at least one printing form is arranged to be shiftable on the exterior surface of the outer wall in a tight fit manner.

[00136] According to an embodiment of the current invention, the at least one printing form is an elastomeric and/or polymeric printing form and is made of rubber, and/or photopolymer.

[00137] According to an embodiment of the current invention, each inlet channel is suitable for gas supply from at least one connecting element, and/or at least one ring and at least one groove are located at a side of the main body, and the at least one ring and the at least one groove are suitable for creating an gas pocket when mounting a printing form from the side of the main body.

[00138] According to an embodiment of the current invention, the main body has a cylinder shape, and the main body comprises at least one of a print cylinder, an adapter, an adapter mounted on a printer cylinder, and an adapter mounted onto a press mandrel.

[00139] According to an embodiment of the current invention, the outlets are through-holes, and walls forming the at least two compartments are walls inside the main body, and/or multiple through- holes connect to a compartment and the through-holes are evenly located on a circle on the exterior surface of the main body, which circle is parallel to a circumference of the main body.

[00140] According to an embodiment of the current invention, the main body further comprising at least two tubes, wherein each of the tube is connected to at least one inlet channel, each tube comprises a compartment part, each of the at least two compartments is formed by a compartment part of a tube, and each compartment part comprises at least one outlet. [00141] According to an embodiment of the current invention, the tubes locate in grooves of the main body, and the tubes do not extend from the exterior surface of the main body.

[00142] According to an embodiment of the current invention, a sheet layer covers the whole exterior surface of the main body or pieces of sheet layers cover the grooves of the main body, and wherein multiple outlets on the sheet layer or the pieces of sheet layers match to the outlets on the tubes.

[00143] According to an embodiment of the current invention, a method for forming an apparatus, comprises the following actions:

a. providing an apparatus comprising a main body, the main body comprising:

i. an outer wall with an exterior surface,

ii. at least two compartments in the main body, and

iii. at least two inlet channels;

iv. at least two outlets,

wherein each compartment connects to at least one outlet and at least one inlet channel, such that gas is able to flow from each inlet channel to at least one outlet via at least one compartment, wherein the at least two compartments are separated from each other such that the gas is not able to exchange between the at least two compartments;

b. moving a first printing form over the main body and supplying gas to at least one outlet via at least one inlet channel and at least one compartment;

c. expanding the first printing form by the gas flowing from the at least one outlet;

d. moving the first printing form to a first position; and

e. discontinuing supplying gas to outlets that are covered by the first printing form such as to retain the first printing form in a tight fit connection on the main body in the first position.

[00144] According to an embodiment of the current invention, the method further comprises before step a, mounting connecting elements and/or a switch unit on the main body such that each connecting element is connected to at least one inlet channel, and/or the switch unit comprises at least one switch, which is configured for controlling gas supply from a source to each connecting element.

[00145] According to an embodiment of the current invention, the method further comprises the following steps while discontinuing supplying gas to through-holes that are covered by any printing form retaining on the main body:

f. moving a further printing form from a set of printing forms over the main body and supplying gas to at least one outlet that is not covered by any retained printing form, via at least one inlet and at least one compartment;

g. expanding the further printing form by the gas from the at least one outlet that is not covered by any printing form retaining on the main body;

h. moving the further printing form to a further position on the external surface;

i. discontinuing supplying gas to outlets that are covered by the further printing form such as to retain the further printing form in a tight fit connection on the main body in the further position; and j. repeating steps f to i until all printing forms of said set of printing forms are mounted to the main body.

[00146] According to an embodiment of the current invention, when a printing form retains on the main body, the method further comprises demounting the printing form by the following steps: k. supplying gas to at least one outlet that is covered by the printing form to be demounted;

L. expanding the printing form to be demounted by the supplied gas; and

m. moving the printing form to be demounted from the main body.

[00147] According to an embodiment of the current invention, the moving of the printing form comprises at least one of: axially and/or rotationally moving the printing form; and/or axially and/or rotationally moving the main body; and/or contacting the printing form with a push sleeve and moving the printing form by the push sleeve.

[00148] The embodiment in figs. 7A to 7E has additional advantages when compared to the prior art rolls. For example, in fig. 2, air with high pressure is supplied to the inside compartment of the main body. Therefore, the main body bears a high air pressure from inside, which can deform the shape of the main body (for example expanded temporarily or permanently) and eventually reduce the printing quality. Furthermore, when suffering from the high air pressure for a long time, the lifetime of the main body may be severely reduced. When the main body is damaged, the whole roll needs to be repaired or replaced which increases the overall printing cost. Therefore, the main body can be regarded as a pressurized vessel and it has to meet the regulations for pressurized vessels for example for safety reasons. Additionally, large amount of pressurized air is needed to fill the compartment inside the main body in fig. 2. The operations of the individual sleeves on the main body, e.g., moving, adjusting and fixing of the sleeves, may be difficult due to the large volume of air that needs to be controlled. It is also not easy to manufacturing a main body with a structure as in fig. 2 where compartments and channels are integrated with the main body, which may require specific materials for the main body and specific manufacturing steps to form the compartments and channels inside the main body.

[00149] However, with the embodiments in figs. 7A to 7E, air is supplied and reaches the outlets via tubes 721 -727 in the grooves on the surface of the main body 710, which reduces the amount of pressurized air needed. Furthermore, the main body 710 itself does not suffer from any high air pressure, instead the high air pressure is applied to separate tubes 721 -727. Therefore, the high air pressure can only possibly damage the tubes 721 -727, which are very easy to be replaced or repaired one by one. Therefore, the lifetime ofthe main body and the roll is prolonged. Furthermore, it is very easy to manufacture the main body 710 because only grooves on the surfaces are needed, which reduces the manufacturing cost.

[00150] According to any embodiments of the present invention, the sleeves may be printing sleeves or adapting sleeves. When the sleeves are adapting sleeves, an extra layer of printing sleeve(s) may be mounted over the adapting sleeves. Because the adapting sleeves can be changed and replaced easily according to present invention, the thickness of the adapting sleeves can be changed according to the dimensions of the printing sleeves. Eventually, the printing length (circumference length of the printing sleeve(s)) can be changed easily without change the dimensions of the roll. The adapting sleeves may cover the whole length of the main body. When adapting sleeves are mounted on the main body side by side without a gap, seamless printing can be achieved.