BACKGROUND

[0001] Printers can be used to generate images. Printers include pens or ink cartridges that can be controlled to dispense print fluid, such as ink, on desired locations of a substrate to produce an image. The pens may include fluid reservoirs filled with porous media (e.g., solid foam) to assist in delivering the print fluid from the reservoirs to a print die on the pens which are configured to dispense the print fluid. Controlled amounts of print fluid can be dispensed from a pen under the control of a processor of the printer. The printing fluid pens may include black ink or different colors of ink to generate color images.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 is a block diagram of an example imaging device that uses printing fluid pens with side insert capillaries of the present disclosure;

[0003] FIG. 2 is a block diagram of a top, front, side, and back view of an example side insert capillary of the present disclosure;

[0004] FIG. 3 is a block diagram of an example isometric view of a body of the printing fluid pen with slots to receive the side insert capillary of the present disclosure;

[0005] FIG. 4 is a block diagram of an example isometric view of the body of the printing fluid pen with porous media inserted with the side insert capillaries of the present disclosure;

[0006] FIG. 5 is a block diagram of a front isometric and back isometric view of another example side insert capillary of the present disclosure;

[0007] FIG. 6 is an isometric view of the printing fluid pen and lid with the side insert capillaries of the present disclosure; and

[0008] FIG. 7 is a front cross-sectional view of the printing fluid pen and lid with the side insert capillaries of the present disclosure.

DETAILED DESCRIPTION

[0009] The use of a porous media, such as solid foams (referred to herein as foam), within a fluid reservoir in fluid communication with a print die of a pen provides a simple and inexpensive approach to delivering fluid to print dies.

However, the use of foams as a fluid delivery mechanism also introduces other challenges. For instance, determining an amount of fluid in a porous media reservoir can be challenging. Fluids may travel relatively slowly though porous media, and the distribution of fluid within the porous media is highly variable, for instance. Capillary tubes may be used to take advantage of the capillary effects of the porous media in order to determine fluid levels. The capillary tubes may act as capillary sensors when inserted into the porous media reservoirs and may be used to control filling of the porous media reservoirs with print fluid (e.g., when the porous media reservoirs run low on print fluid).

[0010] Previous methods of inserting capillary tubes into the porous media include slitting the porous media and then inserting a capillary sensor.

However, the porous media may be under tension inside of the body of the printing fluid pen. Thus, a high amount of energy may be needed to slit the porous media and then insert the capillary sensor into the slit in the porous media. When the porous media is dry, the amount of friction increases and causes even more energy to be used to insert the capillary sensor.

[0011] When the porous media is wetted by print fluid added to the porous media reservoir, the friction may be reduced. However, it may be difficult to prime the capillary sensor.

[0012] The present disclosure provides a side insert capillary that can be inserted between a wall of the body of the printing fluid pen and a side of porous media inside the body. Sensing electrodes may be inserted into the side insert capillary to detect the presence or absence of print fluid. The electrodes may be communicatively coupled to a processor of a printer to then generate notifications to fill the porous media reservoir or control a tank to release ink to fill the porous media reservoir.

[0013] In an example, the design of the side insert capillary of the present disclosure allows the capillary to be inserted without having to create a slit in the porous media. For example, the side insert capillary may be inserted into the body of the printing fluid pen before the porous media is inserted into the body. In another example, the side insert capillary may be inserted into the body after the porous media is inserted.

[0014] The design of the side insert capillary allows the capillary to be fluidly connected to the porous media. The side insert capillary may include features that help maintain a constant contact against the porous media to automatically prime the capillary. An air vent in the side insert capillary may act as a pressure reference and sensor side insert source of air to backfill the side insert capillary as print fluid enters or leaves the capillary during operation of the printer.

[0015] FIG. 1 illustrates an example imaging device 100 that includes a side insert capillary 104 of the present disclosure. The imaging device 100 may be any type of device used to generate images, graphics, text, and the like. The imaging device 100 may be a printer.

[0016] In an example, the imaging device 100 may include a printing fluid pen 102. The processor 108 may be communicatively coupled to the printing fluid pen 102. The processor 108 may control the printing fluid pen 102 to dispense a printing fluid 106 onto a substrate at desired locations. The printing fluid pen 102 may include several different types of printing fluid 106 (e.g., different colors to print various colored images, text, and/or graphics). The printing fluid pen 102 may include print die (not shown) that include electrically controllable nozzles that can dispense the printing fluid 106 in controlled amounts.

[0017] The imaging device 100 may also include a user interface (III) 110 and a fluid supply 112. The processor 108 may be communicatively coupled to the III 110 and the fluid supply 112. The side insert capillary 104 may be inserted into the printing fluid pen 102 to monitor a printing fluid level within the printing fluid pen 102. [0018] In an example, the side insert capillary 104 may be used to monitor a printing fluid level within the printing fluid pen 102. For example, the side insert capillary 104 may transmit an electric signal to the processor 108 when the printing fluid level inside of the printing fluid pen 102 is not full. In response, the processor 108 may control a pump (not shown) to dispense additional printing fluid 106 from the fluid supply 112 into the printing fluid pen 102.

[0019] In an example, the processor 108 may also generate a notification or a message on the III 110 indicating that the printing fluid level is low or being refilled. The III 110 may be a graphical user interface of the imaging device 100. The III 110 may be a touch screen interface or may include physical buttons for navigating menus and/or confirming selections.

[0020] It should be noted that the imaging device 100 has been simplified for ease of explanation in FIG. 1 and may include additional components that are not shown. For example, the imaging device 100 may include a mechanism to move the printing fluid pen 102 horizontally across a width of a substrate. In an example, the imaging device 100 may also include a memory, a paper tray, a power supply, and the like.

[0021] As noted above, previous designs of capillaries include a slit inside of a porous media reservoir of the printing fluid pen 102. However, attempting to create the slit and/or inserting the capillary into the slit may present challenges, as discussed above.

[0022] The side insert capillary 104 of the present disclosure may be inserted into the printing fluid pen 102 against the porous media reservoir without having to cut a slit inside of the porous media. Depending on the design of the side insert capillary 104, the side insert capillary 104 may be inserted before the porous media reservoir is inserted into a reservoir of the printing fluid pen 102 or may be inserted after the porous media is inserted into a reservoir of the printing fluid pen 102.

[0023] FIG. 2 illustrates an example side insert capillary 200 of the present disclosure. FIG. 2 illustrates a back side view 202, a side view 204, a front side view 206, and a top view 208 of the side insert capillary 200. The side insert capillary 200 may include a body 250 that has a back side 252 shown in the back side view 202 and a front side 254 shown in the front side view 206.

[0024] The back side view 202 shows a capillary feed 210 on the back side 252 of the side insert capillary 200. The capillary feed 210 may be located towards an end of the side insert capillary 200 that is inserted into the porous media.

[0025] In an example, the capillary feed 210 may have an opening width 222. The opening width 222 may be sized based on characteristics of a type of porous media or print fluid 106 that is deployed. The opening width 222 may also be sized based on a correspondence between pressure within a reservoir into which the side insert capillary 200 is inserted and dimensions of the fluid present/not present channel 224 (e.g., depth, width, and height). The opening width 222 should be sized to provide an equal or higher channel capillary pressure than the fluid present/not present channel 224 to enable the capillary feed 210 to be refilled with printing fluid 106 after the reservoir is refilled. In an example, the opening width 222 of the capillary feed 210 may be approximately 0.10 to 0.20 millimeters (mm). In an example, the opening width 222 may be approximately 0.12 mm. The capillary feed 210 may be sized and shaped to establish a continuous fluidic connection with a porous media reservoir of the printing fluid pen 102.

[0026] In an example, the side insert capillary 200 may include a plurality of stand-offs 212i to 212 _n (hereinafter also referred to individually as a stand-off 212 or collectively as stand-offs 212). The stand-offs 212 may be protrusions that are located along a vertical center line of the back side of a body of the side insert capillary 200. The stand-offs 212 may provide support against a wall of the printing fluid pen 102 and maintain an integrity of the fluid present/not present channel 224. For example, the stand-offs 212 may prevent the fluid present/not present channel 224 from being bent under pressure from the porous media against the wall of the printing fluid pen 102.

[0027] In an example, the side insert capillary 200 may include an air vent 214. The air vent 214 may provide a reference pressure and supply make-up air within the side insert capillary 200. In addition, humidified air may be provided into the side insert capillary 200 via the air vent 214 to prevent the printing fluid drawn into the fluid present/not present channel 224 from drying out. Although the air vent 214 is shown as a circular opening in FIG. 2, it should be noted that the air vent 214 may have any shape.

[0028] The air vent 214 may be located towards a top end of the side insert capillary 200. The air vent 214 may be located such that the air vent is above a top of the porous media reservoir within a respective reservoir. Thus, the air vent 214 may provide humidity and a pressure reference, and supply of makeup air as the printing fluid 106 is removed from the reservoir and/or added to the reservoir, as described below.

[0029] In an example, the side insert capillary 200 may include a pair of columnar volumes or pockets 218 to receive a printing fluid level sensor. The fluid present/not present channel 224 may be formed between the pair of columnar volumes 218. In an example, the printing fluid level sensor may include conductive elements that are inserted into the pair of columnar volumes 218.

[0030] The side view 204 illustrates a conductive element 220 that can be inserted into the pair of columnar volumes 218. The conductive element 220 may include electrodes that may make an indirect or direct electrical connection to the processor 108. The conductive element 220 may be connected to a capacitive or a resistive measuring circuit to detect when the printing fluid pen 102 is full or not full. For example, as printing fluid levels change, the capacitance (e.g., measured by the capacitive measuring circuit across conductive elements 220) may change or resistance values (e.g., measured by the resistive measuring circuit across conductive elements 220) may change. In an example, the values of capacitance measured across the conductive elements 220 may be calibrated for the side insert capillary 200 to correspond to full and not-full states, such as within a processor (e.g., processor 108 illustrated in FIG. 1).

[0031] The side view 204 also illustrates a capillary feed mouth 216. The capillary feed mouth 216 may comprise a protrusion. The protrusion may have a thickness 230 of several millimeters (e.g., 2-5 mm). The protrusion may extend into the porous media in the reservoir of the printing fluid pen 102. Pressing the capillary feed mouth 216 into the porous media may help to maintain a fluidic connection between the capillary feed 210 and pores that contain the printing fluid 106 within the porous media. As a result, the capillary feed mouth 216 may ensure that the feed slot 210 refills with the printing fluid 106 when the reservoir is refilled.

[0032] The front view 206 illustrates the air vent 214 that is present on both the front side and back side of the side insert capillary 200. The front view 206 also illustrates an example shape of the capillary feed mouth 216. Although FIG. 2 illustrates the capillary feed mouth 216 as having an oval shape, it should be noted that the capillary feed mouth 216 may have any shape (e.g., rectangular, circular, irregular, a polygon, and the like).

[0033] The top view 208 illustrates the pair of columnar volumes 218 where the conductive elements 220 may be inserted. The top view 208 also illustrates the fluid present/not present channel 224. The opening width 226 of the fluid present/not present channel 224 may be sized based on characteristics of the porous media and the printing fluid 106 that is deployed. The opening width 226 may also be sized based on a correspondence between pressure within a reservoir into which the side insert capillary 200 is inserted and dimensions of the fluid present/not present channel 224 (e.g., depth, width, and height). The opening width 226 should be sized to allow the fluid present/not present channel 224 to have a higher capillary pressure than the porous media when the porous media is saturated to a level that is considered to be full. In an example, the fluid present/not present channel 224 may have an opening width 226 of approximately 0.10 mm to 0.20 mm. In an example, the fluid present/not present channel 224 may have an opening width 226 of approximately 0.12 mm.

[0034] In an example, the side insert capillary 200 may be tuned based on a correspondence that is established between pressure within the fluid supply 112 and the fluid path within the fluid present/not present channel 224. For example, the printing fluid level in the fluid present/not present channel 224 may be based on a correspondence of the dimensions (e.g., cross-sectional area and height) of the fluid present/not present channel 224 and a pressure within fluid supply 112 or the porous media within a reservoir where the side insert capillary 200 is located. Other factors that may affect the fill level of the side insert capillary 200 may include a surface tension of the printing fluid 106, a contact angle of the printing fluid 106 within the fluid present/not present channel 224, a density of the printing fluid 106, acceleration due to gravity, and the like.

[0035] Based on these parameters, a level or height of the printing fluid 106 within the fluid present/not present channel 224 may be set as a threshold for being full. The value read by the printing fluid level sensor at the threshold height may be correlated as being full. Thus, when the printing fluid 106 falls below the threshold height, the side insert capillary 200 may indicate that the respective reservoir or porous media is not full.

[0036] FIG. 3 illustrates a block diagram of an isometric view of an example body 302 of the printing fluid pen 102. In an example, the body 302 may include a plurality of reservoirs 304, 306, and 308. Although three reservoirs are illustrated in FIG. 3, it should be noted that the body 302 may include any number of reservoirs (e.g., a single reservoir, two reservoirs, more than three reservoirs, and the like). Each reservoir of the plurality of reservoirs 304, 306, and 308 may store printing fluid of a different type, such as a different color or composition. For example, the reservoir 304 may store cyan colored printing fluid, the reservoir 306 may store magenta colored printing fluid, and the reservoir 308 may store yellow colored printing fluid. In other examples, other types of fluids, such as pre- or post-print treatment fluids may be stored in one of the reservoirs 304, 306, or 308.

[0037] In an example, the body 302 may include sockets 310, 312, and 314. Each of the sockets 310, 312, and 314 may be formed on a wall of a respective reservoir 304, 306, and 308 to receive a side insert capillary 200 illustrated in FIG. 2. The side insert capillary 200 may be press fit into each respective socket 310, 312, and 314. The back side of the side insert capillary 200 (e.g., the side shown in the back side view 202) may contact the wall of the socket 310, 312, or 314.

[0038] In an example, the side insert capillary 200 may be press fit into the sockets 310, 312, and 314 before the porous media reservoir is inserted into the reservoirs 304, 306, and 308. After the porous media reservoir is placed into the reservoir 304, 306, and 308, the porous media reservoir may expand. The pressure caused by the expansion of the porous media reservoir against the feed capillary mouth 216 may allow the capillary feed 210 to maintain continuous fluidic contact with pores of the porous media reservoir.

[0039] FIG. 4 illustrates an isometric view of an example of the body 302 that includes the side insert capillaries 200 and porous media 316, 318, and 320. As shown in FIG. 4, each reservoir 304, 306, and 308 may include a respective side insert capillary 200i, 2OO2, and 2OO3. In addition, a porous media 316 may be inserted into the reservoir 304, a porous media 318 may be inserted into the reservoir 306, and a porous media 320 may be inserted into the reservoir 308. FIG. 4 illustrates how the air vent 214 of the side insert capillary 2OO2 is above a top level of the porous media reservoir 316 to provide a humidified pressure reference and supply of make-up air. The air vent 214 for the side insert capillaries 200i and 2OO3 may be similarly situated with respect to the porous media 320 and 318, respectively.

[0040] FIG. 4 also shows the conductive elements 220 of the side insert capillaries 200i, 2OO2, and 2OO3. The conductive elements 220 may protrude through a lid 350 of the printing fluid pen and form an indirect or direct electrical connection to the processor 108 and/or other control elements of the imaging device 100. For example, the lid 350 may include through holes 352 that align with the conductive elements 220.

[0041] The lid 350 may also include openings 354, 356, and 358. The opening 354 may be used to refill the reservoir 304. The openings 356 may be used to refill the reservoir 306. The openings 358 may be used to refill the reservoir 308.

[0042] In an example, the porous media 316, 318, and 320 may comprise a porous media. The porous media 316, 318, and 320 may serve as a printing fluid reservoir in fluidic communication with a print die (not shown) and deliver the printing fluid 106 to the print die. The porous media 316, 318, and 320 may comprise an open- or closed-cell foam (e.g., polyurethane (PU), polylolefin fibers, or polyethylene (PE) foam, and the like). The porous media 316, 318, and 320 may have a number of parameters, which may be used to characterize fluid flow through the porous media 316, 318, and 320. The porous media 316, 318, and 320 may allow flow of the printing fluid 106 in response to capillary effects. The capillary effects may induce a negative pressure within the porous media 316, 318, and 320. Parameters of the porous media 316, 318, and 320 may have an effect on a correlation between saturation of the porous media 316, 318, and 320 and pressure.

[0043] For example, the more saturated the porous media 316, 318, and 320 become (e.g., the fluid reservoir in the reservoir 304, 306, or 308 is full), the less negative pressure the porous media 316, 318, and 320 exert. Thus, printing fluid 106 may be drawn into the side insert capillary 200i , 2002, or 2OO3. As a result, the conductive elements 220 may detect a level of printing fluid 106 within the fluid present/not present channel 224 associated with a full level.

[0044] The less saturated the porous media 316, 318, and 320 become (e.g., the fluid reservoir in the reservoir 304, 306, or 308 is not full), the more negative pressure is created in the porous media 316, 318, and 320. Thus, the printing fluid 106 may be drawn out of the side insert capillary 200i , 2OO2, or 2OO3. As a result, the conductive elements 220 may detect a level of printing fluid 106 within the fluid present/not present channel 224 that is below the full level. In response, the processor 108 may re-fill the appropriate reservoir 304, 306, or 308 with printing fluid 106 from the fluid supply 112, as described above. In another example, a notification may be shown on the III 110, and the appropriate reservoir 304, 306, or 308 may be refilled manually.

[0045] Thus, as the printing fluid 106 is dispensed by the printing fluid pen 102 and refilled continuously, the pressure inside of the porous media 316, 318, and 320 may continuously change. The change in pressure may cause the printing fluid level within the fluid present/not present channel 224 to also change. The changes in printing fluid level may be detected by using the conductive elements 220 to monitor the printing fluid level within a respective reservoir 304, 306, or 308. The air vent 214 of the side insert capillaries 200i, 2OO2, and 2OO3 may provide a humidified pressure reference and source of make-up air within the side insert capillaries 200i , 2OO2, and 2OO3 as the printing fluid level changes within the fluid present/not present channel 224.

[0046] FIG. 5 illustrates a block diagram of another example of a side insert capillary 500. FIG. 5 illustrates a front isometric view 502 and a back isometric view 504. The front isometric view 502 illustrates a front half 506 and a back half 508 of the body of the side insert capillary 500. The front half or front side 506 and the back half or back side 508 may be mechanically coupled together to form a body 550 of the side insert capillary 500. For example, the front half 506 and the back half 508 may be snapped together or press-fit together with and adhesive.

[0047] In an example, the side insert capillary 500 may include a capillary feed 512. The capillary feed 512 may be in continuous fluidic contact with the porous media inside of the reservoirs of the printing fluid pen 102. The capillary feed 512 may be similar in dimensions to the capillary feed 210. The opening width of the capillary feed 512 may be sized based on characteristics of a type of porous media that is deployed. The opening width of the capillary feed 512 may also be sized based on a correspondence between pressure within a reservoir into which the side insert capillary 500 is inserted and dimensions of a fluid present/not present channel 520 (e.g., depth, width, and height). The opening width should be sized to provide an equal or higher capillary pressure then the fluid present/not present channel to enable the capillary feed 512 to refill with printing fluid 106 after the reservoir is refilled. For example, the capillary feed 512 may have an opening width of approximately 0.10 to 0.20 millimeters (mm). In an example, the opening width may be approximately 0.12 mm.

[0048] In an example, the side insert capillary 500 may include an air vent 514. The air vent 514 may help provide a pressure reference and a source of make-up air within the side insert capillary 500. In addition, humidified air may be provided into the side insert capillary 500 via the air vent 514 to prevent the printing fluid drawn into the fluid present/not present channel 520, shown in the back view 504, from drying out. Although the air vent 514 is shown as an oval opening in FIG. 2, it should be noted that the air vent 514 may have any shape. [0049] In an example, the side insert capillary 500 may include a tab member 517. The tab member 517 may provide a surface to contact a lid and prevent the side insert capillary 500 from falling through the lid and into the reservoir, as illustrated in FIG. 6 and discussed in further details below. Although the tab member 517 is illustrated as protruding out from the front half 506, it should be noted that the tab member 517 may be deployed in other ways. For example, the tab member 517 may be formed as a lip around a top of the side insert capillary 500.

[0050] In an example, the side insert capillary 500 may also include a tapered end 510. The tapered end 510 may form an angle or a point that may allow the side insert capillary 500 to slide between a wall of the printing fluid pen 102 and a side of the porous media. Thus, the example side insert capillary 500 may be inserted after the porous media is inserted into a reservoir of the printing fluid pen 102.

[0051] The isometric back side view 504 illustrates a pair of columnar volumes or pockets 516. The pair of columnar volumes 516 may receive a printing fluid level sensor. For example, the printing fluid level sensor may include electrically connected conductive elements 530 that are inserted into the columnar volume 516. In an example, the conductive elements 530 may be electrodes that can detect or monitor the printing fluid level inside of a reservoir of the printing fluid pen, as described above.

[0052] The back side view 504 also illustrates the fluid present/not present channel 520. The fluid present/not present channel 520 may be a vertical volume located between the pair of columnar volumes 516. The fluid present/not present channel 520 may receive printing fluid 106 that contacts the conductive elements 530 and allows the conductive elements 530 to measure the printing fluid level based on where the printing fluid 106 contacts a vertical height of the conductive elements 530.

[0053] In an example, the fluid present/not present channel 520 may have an opening width similar to the fluid present/not present channel 224 of the side insert capillary 200. The opening width may be sized based on characteristics of a type of porous media and printing fluid 106 that is deployed. The opening width may also be sized based on a correspondence between pressure within a reservoir into which the side insert capillary 500 is inserted and dimensions of the fluid present/not present channel 224 (e.g., depth, width, and height). The opening width should be sized to allow the fluid present/not present channel 520 to have a higher capillary pressure than the porous media when the porous media is saturated to a level that is considered to be full. For example, the opening width of the fluid present/not present channel 520 may be approximately 0.10 to 0.20 millimeters (mm). In an example, the opening width may be approximately 0.12 mm.

[0054] In an example, the side insert capillary 500 may include flat surfaces 511. In an example, the flat surfaces 511 may include a convex region formed along a back half 508 of the body to reduce part sink during molding.

[0055] FIG. 6 illustrates an isometric view of an example printing fluid pen 602 that includes the side insert capillary 500 illustrated in FIG. 5. The pen 602 may include a body 604 and a lid 606. The body 604 may include a plurality of reservoirs that include a respective porous media, similar to the reservoirs 304, 306, and 308 and the porous media 316, 318, and 320.

[0056] The lid 606 may include openings that allow the side insert capillary 500 to be inserted against a wall of the body 604 and a side of the porous media. The lid 606 may include an opening that is positioned over each reservoir in the body 604. The example illustrated in FIG. 6 illustrates a lid 606 with three openings to insert three side insert capillaries 500i, 5002, and 500s. FIG. 6 also illustrates the conductive elements 514 that protrude from the top of the side insert capillaries 500i, 5002, and 500s. As a result, electrical connections may be made with the conductive elements 514 to monitor a printing fluid level within the respective reservoirs of the body 604.

[0057] FIG. 7 illustrates a cross-sectional view of the printing fluid pen 602. FIG. 7 illustrates reservoirs 608 and 610 of the body 604. The reservoirs 608 and 610 may include respective porous media 612 and 614. The lid 606 may include openings 616 and 618. The side insert capillary 5002 may be inserted through the opening 616 into the reservoir 608. The tapered end 510 of the side insert capillary 5002 may allow the side insert capillary 5002 to be wedged between a wall of the reservoir 608 and a side of the porous media 612 without forming a slit in the porous media 612.

[0058] Similarly, the side insert capillary 500s may be inserted through the opening 618 into the reservoir 610. The tapered end 510 of the side insert capillary 500s may allow the side insert capillary 500s be wedged between a wall of the reservoir 610 and a side of the porous media 614 without forming a slit in the porous media 614.

[0059] Thus, the present disclosure provides different examples of side insert capillaries 104 (e.g., the side insert capillary 200 and the side insert capillary 500). The side insert capillaries 104 may be inserted into reservoirs without forming slits in the porous media to measure a printing fluid level within the reservoir. One example, such as the side insert capillary 200, may be inserted into a reservoir before the porous media is inserted into the reservoir. Another example, such as the side insert capillary 500 may be inserted into a reservoir after the porous media is inserted into the reservoir. In either case, the side insert capillary 200 or 500 can be deployed without forming slits or cutting openings into the porous media.

[0060] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.