ENVELOPE MANUFACTURING PROCESS

FIELD OF THE INVENTION The present invention relates to an envelope manufacturing process. More particularly, but not exclusively, the invention relates to a process for manufacturing envelopes from two continuous sheets of paper.

BACKGROUND OF THE INVENTION

It has been previously proposed to form envelopes by trimming a single sheet of paper to form joining tabs around particular edges of the sheet, folding and applying glue to the tabs, and then folding the sheet to form an envelope. Machines used in such processes may manufacture hundreds of envelopes per minute. To do this, the moving parts of such machines may be required to travel at high speeds and are subject to large accelerations to perform operations such as trimming and folding. Accordingly, it is desirable to minimise the size of moving parts to keep inertial forces at a minimum.

As the size of the envelope increases, a larger machine is required as a larger piece of paper requires folding, thus increasing the size of moving parts which are required to complete the folding operation. Due to the increased mass of these parts, the speed at which the machine can operate is reduced as the size of an envelope increases.

Examples of the invention seek to solve, or at least ameliorate, one or more disadvantages of previous envelope manufacturing processes. SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided an envelope manufacturing process, the process including the steps of:

streaming a first length of material;

trimming side edges of the first length of material to form lateral joining tabs along lateral sides of the first length of material;

folding the lateral joining tab(s) along at least one of the sides;

moving a second envelope panel so that it is adjacent the first length of material; bringing the second envelope panel into engagement with the folded joining tab(s); severing a leading portion from the first length of material to form a first envelope panel having transverse joining tabs along its front and rear sides;

folding at least one of the transverse joining tabs over an edge of the second envelope panel so that joining tabs are folded along at least three sides of the first envelope panel; and

fixing at least one of the folded transverse tab(s) to the second envelope panel to form an envelope.

According to a second aspect of the present invention, there is provided an envelope manufacturing process, the process including the steps of:

streaming a first length of material;

trimming side edges of the first length of material to form lateral joining tabs along lateral sides of the first length of material;

moving a second envelope panel so that it is adjacent the first envelope panel: bringing the second envelope panel into engagement with the first envelope panel; folding at least one of the lateral joining tabs over an edge of the second envelope panel and fixing the folded tabs to the second envelope panel;

severing a leading portion from the first length of material to form a first envelope panel having transverse joining tabs along its front and rear sides;

folding at least one of the transverse joining tabs over an edge of the second envelope panel so that joining tabs are folded over at least three sides of the second envelope panel; and

fixing at least one of the folded transverse tab(s) to the second envelope panel to form an envelope. Preferably, the second envelope panel is moved so that it is suspended above the first envelope panel.

Preferably, the second envelope panel has a width which is smaller than that of the first length of material.

Preferably, the second envelope panel forms part of a continuous second length of material. Alternatively, the second envelope panel can be severed from a streaming second length of material. Preferably, the second length is streaming at a slower speed than the first length of material.

Preferably, the first length of material is severed along a transverse line extending across the first length of material from a position between consecutive lateral joining tabs. The process can further include the step of scoring the first length of material to define an outline of an internal area of the envelope.

The lateral joining tabs can be folded using guide rails. A rear transverse joining tab can be folded by drawing the envelope panel backwards and downwards against a guide member. At least one of the joining tabs can be a sealable closure. The step of bringing the second envelope panel into engagement with the first envelope panel can include applying adhesive to the first envelope panel or the second envelope panel. Preferably, the adhesive is applied to the joining tabs of the first envelope panel. The second envelope panel can be engaged with a vacuum cylinder to suspend it above the first length of material. Preferably, the second envelope panel and the first length of material are formed of paper. The second envelope panel and the first length of material can be formed of different grades of paper.

The first and second lengths of material can be streamed from first and second webs.

According to the present invention, there is also provided an envelope manufactured using a process of the above described type.

According to the present invention, there is also provided an apparatus for manufacturing an envelope using a process of the above described type.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described, by way of non-limiting example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of an envelope manufacturing process of one embodiment of the invention;

Figure 2 is a schematic diagram of another envelope manufacturing process;

Figure 3 is a schematic diagram of an apparatus used to perform the process of Figure 2;

Figure 4 is a plan view of envelope panels for use in the processes;

Figure 5 is a plan view of a continuous sheet of paper for use in the processes; Figure 6 is a process flow chart of an envelope manufacturing process of one embodiment; and

Figure 7 is a process flow chart of an envelope manufacturing process of another embodiment. DETAILED DESCRIPTION

With reference to Figure 1, there is shown a schematic diagram of an envelope manufacturing process 10. In this process, a first length of material 14, which in the described example is paper, is streaming from a continuous first paper web 12. As the length of paper 14 is streaming, lateral joining tabs are formed at 16. These joining tabs are formed by trimming side edges of the length of paper, in particular, cutting notches out of the side edges of the length of paper 14. The joining tabs may be trimmed using a wing or fly knife or, alternatively, by a rotary knife such as a cylinder with a magnetic foil.

As illustrated in Figure 5, the trimming process cuts notches 38 in the length of paper 14 to form an outline of the lateral joining tabs 40 and a partial outline of transverse joining tabs which include a front or leading edge joining tab 42 and a rear or trailing edge joining tab 44. In the example shown, the leading edge joining tab 42 is shown larger than the trailing edge joining tab 44, though it will be appreciated that the trailing edge joining tab 44 may be made larger than the leading edge joining tab 42. The notches 38 may have linear sides, resulting in the joining tabs having straight sides as shown in Figure 5, or a curved profile as shown in Figure 4. The lateral joining tabs 40 along each side may be a singular tab or include multiple joining tabs.

The step of severing a leading portion from the length of paper 14 at 30 (to be further described later) to form a first envelope panel 32 completes the forming the leading edge and trailing edge joining tabs 42, 44 which are partially formed by trimming the notches out of the side edges of the length of paper 14. Step 30 may be performed before or after the joining tabs are trimmed, in which case the outline of the joining tabs would be complete after the trimming process. In some examples, the lateral joining tabs 40 may be trimmed independently from the transverse joining tabs.

The process includes step 18, folding the lateral joining tabs 40. The lateral joining tabs 40 are folded using, for example, guide rails. In some examples, only the lateral joining tab(s) along one side of the length of paper 14 are folded and the joining tab(s) which have not been folded may later become an opening which a user can seal after contents have been inserted in the envelope.

A second envelope panel 26, such as the one illustrated in Figure 4, is moved so that it is adjacent the first length of paper 14. In this regard, the second envelope panel 26 may be above, below or in a side-by-side relationship with the first length of paper 14. In the described example, the second envelope panel 26 is moved so that it is suspended above the first length of paper 14. The second envelope panel 26 is severed from a second length of material, which in the described example is also paper, which is streaming from a second continuous web 20. The second envelope panel 26 is severed from the second continuous web 20 at step 24. The second envelope panel 26 has a smaller width than the first length of paper 14. As joining tabs are formed on the first length of paper 14, the second envelope panel 26 does not require trimming and waste can be reduced, advantageously reducing the amount of paper used in the process. Furthermore, the process allows envelopes to be manufactured having different grades of paper for either panel. The second envelope panel 26 is suspended above the first length of paper 14 by a vacuum cylinder (not shown). In other examples, the second envelope panel 26 is suspended above the first length of paper 14 using a mechanical device which holds the second envelope panel 26 in a desired position above the first length of paper 14 until it is brought into engagement with the first length of paper 14.

The diameter of the vacuum cylinder is relatively large compared to conventional vacuum cylinders so that the motion of the second envelope panel 26 is generally linear over a short distance. The size of the vacuum cylinder also allows it to hold multiple sheets at one time.

As joining tabs are not formed on the second envelope panel 26, its length is not reduced in the same manner as the first length of paper and the second length of paper is used at a slower rate and therefore streamed at a slower speed than that of the first length of paper 14. Because the vacuum cylinder is configured to suspend the second envelope panel 26 above the first length of paper 14, the second envelope panel 26 needs to be moving at the same speed as the first length of paper 14 and is thus accelerated upon contact with the vacuum cylinder from the speed at which the second length of paper is streaming to the speed of the first length of paper 14.

The second envelope panel 26 is then brought into engagement with the first length of material 14, in particular the folded joining tabs 40, at 28. In the described example, the step of bringing the second envelope panel 26 into engagement with the first length of material 14 includes applying adhesive to the joining tabs 40 which are to be engaged by the second envelope panel 26. In some examples, joining tabs along each side of the length of material may be folded, but glue may be applied to only tabs along one of those sides so that an opening through which contents may be stored is provided.

In the described example, the second envelope panel 26 is severed from the second length of paper 22 before it is brought into engagement with the first length of paper 14. It will be appreciated that in other examples, the second length of paper 22 is not severed, but brought into engagement with the first length of paper 14 as a continuous web of paper.

Referring to Figure 2, there is shown a schematic diagram of another envelope manufacturing process 1 10. A number of the steps of process 1 10 are the same as those of process 10, though provided in a different order, and thus have been similarly numbered.

In particular, the lateral joining tabs which are formed at step 1 16 are folded after the second envelope panel 26 is brought into engagement with the first length of material 14 at step 128. In some examples, only the lateral joining tab(s) along one side of the length of paper 14 are folded and the joining tab(s) which have not been folded may later become an opening which a user can seal after contents have been inserted in the envelope. An adhesive may be applied to corners of either the first length of material 14 or the second envelope panel 26 to hold the second envelope panel 26 to the first length of material 14 until the lateral joining tabs 40 are folded over an edge of the second envelope panel 26.

In this example, the process includes the steps of streaming a first length of material 14, trimming side edges of the first length of material 14 to form lateral joining tabs 40 along lateral sides of the first length of material 14, moving a second envelope panel 26 so that it is suspended above the first length of material 14, bringing the second envelope panel 26 into engagement with the first length of material 14 and folding the lateral joining tabs 40 over edges of the second envelope panel 26 to form an envelope 36.

Again, it will be appreciated that in some examples, the second length of paper 22 may not be severed, but brought into engagement with the first length of paper 14 as a continuous web of paper. In each of processes 10, 1 10, a leading portion of the first length of paper 14 is severed at step 30, 130, to form a first envelope panel 32, the first envelope panel 32 having a leading edge joining tab 42, a trailing edge joining tab 44 and lateral joining tabs 40. The leading portion is severed along a transverse line extending across the first length of paper 14 from a position between consecutive lateral joining tabs so that each of the joining tabs 40. 42, 44 are separated by the notches 38 which have been trimmed in the side edges of the length of paper 14.

Either or both of the leading edge and trailing edge joining tabs 42, 44 are folded at step 34, 134, depending on whether both of the lateral joining tabs 40 have previously, or are to be, folded. This is done so that the envelope 36, 136 has joining tabs folded along at least three of its sides, leaving one tab free to allow access for contents to be inserted into it. The trailing edge joining tab 44 may be folded after the leading edge joining tab 42 is folded or prior to it being performed. Folding the leading edge joining tab 42 may be achieved by bringing the moving envelope panel into contact with a guide bar or other stationary bar to force the tab to fold as the panel moves through the process. The trailing edge joining tab 44 may be folded by quickly drawing the first envelope panel 32 backwards and downwards against a rigid member, such as a guide bar, to fold the joining tab. The described processes include the step of scoring the first length of paper 14 to allow the joining tabs to be easily folded. Scoring the first length of paper defines an outline 48 of an internal area of the envelope 36, 136. The step of scoring the first length of paper may be performed in a conventional manner before or after the first length of paper has been trimmed. In some embodiments in which large envelopes are being manufactured, it may be necessary to perform a combination of perforating/scoring to define the outline 48.

Either the leading edge joining tab 42 or the trailing edge joining tab 44 can be a sealable closure so that contents can be stored within the envelope and secured. A peel and stick type adhesive may be applied to the closure so that it can be sealed when desired.

In each of the described examples, as the second envelope panel 26 and the first envelope panel 32 are formed from separate panels, these sheets may be formed of different grades of paper. The schematic diagrams of Figures 1 and 2 illustrate the steps of the process as being performed independently, though it will be appreciated that each of the steps may be performed by a single machine, such as that diagrammatically shown in Figure 3.

Figure 3 illustrates diagrammatically how process 1 10 may be performed on a single machine 100. Machine 100 is based on a conventional envelope manufacturing machine, though modified to perform process 1 10. In this regard, a first length of paper 1 14 is streamed from a first paper web 112 (not shown). Side edges are trimmed at step 1 16 (not shown) to form lateral joining tabs 40 (refer Figure 5) along sides of the first length of paper 1 14.

A second length of paper 122 is streamed from a second paper web 120. The second length of paper 122 is disposed adjacent the first length of paper 1 14 and passes over a pair of rollers 123 to bring it into alignment with the first length of paper. It will be appreciated that the first paper web 112 could also be disposed above or otherwise inline with the second paper web 120.

An adhesive controller 121 is provided to apply 2 small portions or dots of adhesive to opposite sides of the first length of paper 14 at step 125 so that when the second envelope panel 26 is brought into contact with the first length of paper 14, it can be held in position. The adhesive controller 121 also applies adhesive to the lateral joining tabs 40 at step 129.

The second length of paper 22 is trimmed at step 24 to form a second envelope panel 26 and the second envelope panel 26 is brought into contact with the first length of paper 14 at step 128. The adhesive applied at step 129 helps to maintain alignment of the second envelope panel 26 with the first length of material 14.

At step 1 18, the lateral joining tabs 40 are folded to bring them into contact with the second envelope panel 26. The adhesive applied at step 129 acts to fix the lateral joining tabs 40 to the second envelope panel 26. At step 130 the first length of paper 14 is trimmed to form individual envelopes panels 32.

At step 133 adhesive is applied to a joining tab 42 at a leading edge of the envelope panel, the joining tab 42 being created by the trimming at step 130. At step 134 this joining tab is folded so as to fix it to the second envelope panel 26.

It will be appreciated by those skilled in the art that steps 1 18, 130, 133 and 134 would be performed in the same manner as they would be performed by existing envelope manufacturing machines. Although not shown, it will be appreciated that process 10 may be performed on a similarly configured single machine. Those skilled in the art will appreciate that it is not essential that each step be performed in the order described and that variations in the order of the steps are possible. For example, a first envelope panel may be severed from a leading portion of the first length of material prior to the second envelope panel being brought into engagement with the first length of material.

With reference to Figure 6, there is shown a process flow chart of an envelope manufacturing process 210. The process includes step 212, streaming a first length of material. The first length of material is formed of paper, though other materials may also be used.

Step 214 includes trimming side edges of the first length of material to form lateral joining tabs along lateral sides of the first length of material. These joining tabs may be formed independently of each other or in a single step.

Step 216 includes folding the joining tabs along at least one of the sides of the first length of material. Step 218 includes moving a second envelope panel so that it is adjacent the first length of material. As joining tabs are formed on the first length of material, the second envelope panel has a smaller width than the first length of material.

Step 220 includes bringing the second envelope panel into engagement with the folded joining tabs to form an envelope. Step 220 may include applying adhesive to either envelope panel, in particular the joining tabs of the first envelope panel.

Step 222 includes severing a leading portion from the length of material to form a first envelope panel having transverse joining tabs along its front and rear sides. This step may be performed using any conventional cutting apparatus. Severing a leading portion from the length of material completes the forming of the transverse joining tabs. Step 224 includes folding at least one of the transverse joining tabs so that the first envelope panel has folded joining tabs along at least three of its sides. The front transverse joining tab may be folded by bringing the first envelope panel into contact with a guide bar or other stationary member and the rear transverse joining tab may be folded by quickly drawing the envelope panel backwards and downwards against a member to fold the tab. The members may be stationary or may be moving.

A person skilled in the art will appreciate that the order in which the steps of the process are conducted may be varied. For example, Figure 7 illustrates another envelope manufacturing process 310 in which step 320, which is equivalent to step 220 is performed before step 316 (equivalent to step 216). Likewise, step 218 may be performed before step 216. The steps shown in the flow chart of Figure 7 are similarly numbered to those shown in Figure 6. In this regard, step 312 relates to streaming a first length of material, step 314 relates to trimming side edges of the first length of material to form lateral joining tabs along lateral sides of the first length of material, step 318 relates to moving a second envelope panel so that it is adjacent the first length of material, step 320 relates to bringing the second envelope panel into engagement with the folded joining tabs to form an envelope, step 316 relates to folding the joining tabs along at least one of the sides of the first length of material, step 322 relates to severing a leading portion from the length of material to form a first envelope panel having transverse joining tabs along its front and rear sides and step 224 relates to folding at least one of the transverse joining tabs so that the first envelope panel has folded joining tabs along at least three of its sides.

The described processes avoid the need for a large sheet of paper to be folded in half, thus reducing the size of machines used to implement the process and allowing envelopes made using this process to be manufactured faster and more efficiently. Handling of envelope panels is also reduced as the previous steps of die cutting followed by forming, folding and glueing can now be performed in a single process. Also, as the second or upper envelope panel does not require any trimming or folding operations to be performed on it, paper wastage may be minimised and the complexity of machines used to implement the described process may be reduced. Furthermore, different grades of paper may be used for either panel.

The embodiments have been described by way of example only and modifications are possible within the scope of the invention disclosed. For example, certain steps of the process may be interchangeable.