Liquid dispensing device

Abstract

To easily wipe off a high viscosity liquid and to suppress damage of a wiper.SOLUTION: A cover 30 includes: an upstream part 31 which covers an upstream end of a nozzle surface 11x in a wiping direction; and a downstream part 32 which is opposite to the upstream part 31 in a wiping direction. In a direction (a vertical direction) perpendicular to the nozzle surface 11x, a lower surface of the downstream part 32 of the cover 30 is located between the nozzle surface 11x and a lower surface of the upstream part 31 of the cover 30.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device that includes a wiper and a cover that covers the end of a nozzle surface. [Background technology]

[0002] Patent Document 1 discloses a liquid ejection device (liquid ejection device) equipped with a wiping member (wiper) and a fixed member (cover) that covers the end of the nozzle formation surface (nozzle surface). The fixed member covers the upstream end of the nozzle formation surface in the wiping direction, while leaving the downstream end of the nozzle formation surface in the wiping direction exposed. This makes it easy to wipe the liquid from the nozzle formation surface even if the viscosity of the liquid becomes high. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-169700 Summary of the Invention [Problem to be solved by the invention]

[0004] Burrs may form on the edges of the nozzle surface during the process of forming the members that make up the nozzle surface. With the configuration of Patent Document 1, although it is easy to wipe away highly viscous liquids, because the surface of the downstream part in the wiping direction of the fixed member (cover) is located above the nozzle forming surface (nozzle surface), the wiping member (wiper) may come into contact with and be damaged by burrs formed on the downstream end of the nozzle forming surface (nozzle surface) in the wiping direction.

[0005] An object of the present invention is to provide a liquid ejection device that can easily wipe away highly viscous liquid and can prevent damage to the wiper. [Means for solving the problem]

[0006] The liquid ejection device of the present invention comprises a nozzle surface having a plurality of nozzles opening therein, a wiper, a moving mechanism for moving the nozzle surface and the wiper relatively to one another, and a control unit, wherein the control unit controls the moving mechanism to perform a wiping process in which the wiper and the nozzle surface are moved relatively to one another in a wiping direction parallel to the nozzle surface while the wiper is in contact with the nozzle surface, and further comprises a cover that covers at least the upstream end of the nozzle surface in the wiping direction, wherein the cover has an upstream portion that covers the upstream end of the nozzle surface and a downstream portion that is opposite the upstream portion relative to the nozzle surface in the wiping direction, and wherein in a height direction perpendicular to the nozzle surface, the surface of the downstream portion is located between the nozzle surface and the surface of the upstream portion. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a plan view of a printer 100 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the head 1 as seen from below. [Figure 3] FIG. 3 is a cross-sectional view of the head 1 taken along line III-III in FIG. 2. [Figure 4] FIG. 4 is a partially enlarged view of FIG. [Figure 5] FIG. 2 is a block diagram showing the electrical configuration of the printer 100. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Overall printer configuration> First, with reference to FIG. 1, the overall configuration of a printer 100 according to an embodiment of the present invention will be described.

[0009] The printer 100 includes a head unit 1u including three heads 1, a platen 3, a transport mechanism 4, three wipers 5, and a control unit .

[0010] The head unit 1u is a line type that is elongated in the paper width direction (a direction perpendicular to the vertical direction) and ejects ink from nozzles 11n (see Figure 2) onto paper 9 while being fixed in position. Each of the three heads 1 is elongated in the paper width direction and is arranged in a staggered pattern in the paper width direction. The underside of each head 1 is a nozzle surface 11x with multiple nozzles 11n opening (see Figure 2). When the driver IC 1x (see Figure 5) of each head 1 is driven under the control of the control unit 10, ink is selectively ejected from the multiple nozzles 11n of each head 1.

[0011] The platen 3 is a flat plate member that is disposed below the head unit 1u and extends in a direction perpendicular to the vertical direction.

[0012] The transport mechanism 4 has two roller pairs 4a and 4b arranged on either side of the platen 3 in the transport direction (the direction perpendicular to the vertical direction and the paper width direction), and a transport motor 4x (see FIG. 5) that rotates the roller pairs 4a and 4b. When the transport motor 4x is driven under the control of the control unit 10, the roller pairs 4a and 4b rotate while sandwiching the paper 9, and the paper 9 is transported in the transport direction.

[0013] Each of the three wipers 5 is a flexible plate-like member that is provided vertically and is used for wiping (wiping the nozzle surface 11x). Each wiper 5 extends in the paper width direction and overlaps one of the three heads 1 included in the head unit 1u in the transport direction. The wiper 5 has a home position between the roller pair 4a and the head unit 1u in the transport direction. When the wiper motor 5x (see FIG. 5) is driven under the control of the control unit 10, the wiper 5 moves from the home position in the wiping direction, moving while contacting the nozzle surface 11x of the corresponding head 1, and then reaches a stopping position between the head unit 1u and the roller pair 4b. The wiping direction is parallel to the nozzle surface 11x and the same direction as the transport direction. The wiper motor 5x corresponds to the "moving mechanism" of this invention.

[0014] As shown in Fig. 5, the control unit 10 has a ROM (Read Only Memory) 10a, a RAM (Random Access Memory) 10b, and an ASIC (Application Specific Integrated Circuit) 10c. The ROM 10a stores programs and data for the ASIC 10c to control various operations. The RAM 10b temporarily stores data used when the ASIC 10c executes a program. The ASIC 10c executes recording processing, wiping processing, etc. in accordance with the program stored in the ROM 10a.

[0015] In the recording process, the control unit 10 controls the transport motor 4x based on a recording command (including image data) received from an external device (such as the PC 200 shown in FIG. 2) to carry out a transport process in which the paper 9 passes below the head 1 (the space facing the nozzle surface 11x), and controls the driver IC 1x of each head 1 to carry out an ejection process in which ink is selectively ejected from the multiple nozzles 11n of each head 1. In this way, an image is recorded on the paper 9.

[0016] During the wiping process, the control unit 10 controls the wiper motor 5x to move the wiper 5 in the wiping direction while keeping it in contact with the nozzle surface 11x, while maintaining the acute angle θ between the wiper 5 and the nozzle surface 11x (more specifically, the angle θ between the wiper 5 and the portion of the nozzle surface 11x downstream of the wiper 5 in the wiping direction) at 45 degrees, as shown in FIG. 3. The wiper 5 and the nozzle surface 11x move relative to each other. As a result, the wiper 5 wipes away ink and foreign matter (paper dust, etc.) on the nozzle surface 11x.

[0017] Although not shown in FIG. 3, during the wiping process, the wiper 5 moves in the wiping direction with its tip (upper end) in contact with the nozzle surface 11x and in a bent state.

[0018] In this embodiment, the ink ejected from the nozzle 11n is an ink in which the pigment is coated with polymer particles (PP ink: Polymer Particle Ink). The ink present on the nozzle surface 11x is wiped off by the wiper 5.

[0019] <Head configuration> Next, the configuration of the head 1 will be described.

[0020] The head 1 includes a flow path unit, an actuator unit, a driver IC 1x, and a cover 30.

[0021] The flow path unit includes a nozzle plate 11 that constitutes a nozzle surface 11x, and multiple plates. The nozzle plate 11 and multiple plates are stacked vertically and bonded to each other with an adhesive. Each plate has through-holes and recesses that constitute the flow path. The nozzle plate 11 is formed by pressing a plate made of metal such as SUS (Steel Use Stainless). The nozzles 11n are formed from through-holes formed in the nozzle plate 11, and constitute the ends of the flow paths.

[0022] The actuator unit is disposed on the upper surface of the flow path unit (the surface opposite to the nozzle surface 11x). The actuator unit has an electrode electrically connected to the driver IC1x, and when the potential of the electrode is changed by the driver IC1x, energy is applied to the ink in the flow path of the flow path unit to eject the ink from the nozzle 11n.

[0023] The cover 30 is attached to the lower part of the flow path unit. The cover 30 is a rectangular frame-shaped member made of epoxy resin, and surrounds the periphery of the nozzle surface 11x (see FIG. 2). The cover 30 has an upstream section 31 located upstream in the wiping direction, and a downstream section 32 located downstream in the wiping direction (on the opposite side of the upstream section 31 with respect to the nozzle surface 11x in the wiping direction). The upstream section 31 and the downstream section 32 are spaced apart from each other in the wiping direction and extend in the paper width direction. A gate remnant 30g of the cover 30 is formed at the downstream end of the downstream section 32 in the wiping direction. The gate remnant 30g is a mark left by a hole through which resin material is poured during injection molding.

[0024] 3, the upstream section 31 covers the upstream end of the nozzle surface 11x in the wiping direction (i.e., overlaps with the nozzle surface 11x in the vertical direction). On the other hand, the downstream section 32 does not cover the downstream end of the nozzle surface 11x in the wiping direction (i.e., does not overlap with the nozzle surface 11x in the vertical direction). The vertical direction is the direction perpendicular to the nozzle surface 11x and corresponds to the "height direction" of the present invention.

[0025] 2, the nozzle surface 11x has a substantially rectangular shape, but has projections and recesses formed on the downstream end in the wiping direction. In other words, the downstream end of the nozzle surface 11x in the wiping direction has a base 11x1 and a protrusion 11x2 that protrudes from the base 11x1 toward the downstream side in the wiping direction.

[0026] As shown in Figures 2 and 3, the downstream portion 32 faces the downstream end of the nozzle surface 11x in the wiping direction, and is in contact with the protrusion 11x2 but not in contact with the base 11x1 (i.e., it is spaced apart from the base 11x1 in the wiping direction).

[0027] As shown in FIG. 3, the upstream portion 31 and the downstream portion 32 of the cover 30 have different thicknesses, with the upstream portion 31 being thicker than the downstream portion 32.

[0028] The lower surface (surface) of the upstream section 31 and the lower surface (surface) of the downstream section 32 are both located below the nozzle surface 11x, but the lower surface of the upstream section 31 is located below the lower surface of the downstream section 32. In other words, the vertical distance c between the lower surface of the upstream section 31 and the nozzle surface 11x is greater than the vertical distance b between the lower surface of the downstream section 32 and the nozzle surface 11x. In the vertical direction, the lower surface of the downstream section 32 is located between the nozzle surface 11x and the lower surface of the upstream section 31.

[0029] As described above, the nozzle plate 11 is formed by pressing a metal plate. In this case, burrs are particularly likely to occur at the end of the nozzle surface 11x. In this embodiment, the downstream end of the nozzle surface 11x in the wiping direction has irregularities (see FIG. 2), and burrs X are likely to occur at the tip of the protrusion 11x2 (see FIG. 3).

[0030] Here, the protruding height (distance b) of the downstream portion 32 from the nozzle surface 11x is smaller than the protruding height (distance c) of the upstream portion 31 from the nozzle surface 11x, and is also smaller than the distance a between the downstream portion 32 and the base portion 11x1 in the wiping direction, but is larger than the protruding height d of the burr X from the nozzle surface 11x. For example, a = 200 μm, b = 80 μm, c = 250 μm, and d = 20 μm.

[0031] In the wiping process, the wiper 5 first contacts the underside of the upstream portion 31 of the cover 30, passes over the step between the upstream portion 31 and the nozzle surface 11x, and then contacts the upstream end of the nozzle surface 11x in the wiping direction. The wiper 5 then moves from the upstream end of the nozzle surface 11x in the wiping direction toward the downstream end (see FIG. 3), and at the downstream end of the nozzle surface 11x in the wiping direction, after passing the base portion 11x1, contacts the downstream portion 32 of the cover 30 before reaching the tip of the protrusion 11x2 (the portion where the burr X occurs) (see FIG. 4). Thereafter, the wiper 5 passes over the step between the downstream portion 32 and the nozzle surface 11x without contacting the burr X, and contacts the underside of the downstream portion 32 of the cover 30.

[0032] As described above, according to this embodiment, the lower surface (surface) of the downstream portion 32 of the cover 30 is located vertically between the nozzle surface 11x and the lower surface (surface) of the upstream portion 31 of the cover 30 (see FIG. 3). In this case, first, because the downstream portion 32 of the cover 30 protrudes further than the nozzle surface 11x, during the wiping process, the wiper 5 is likely to come into contact with the downstream portion 32 of the cover 30 before reaching the downstream end of the nozzle surface 11x in the wiping direction (the tip of the protruding portion 11x2 where the burr X is generated). Therefore, even if the burr X is generated at the downstream end of the nozzle surface 11x, the wiper 5 is unlikely to come into contact with the burr X, and damage to the wiper 5 can be suppressed. Furthermore, because the downstream portion 32 of the cover 30 does not protrude further from the nozzle surface 11x than the upstream portion 31, the difference in level between the downstream portion 32 of the cover 30 and the nozzle surface 11x can be kept low, and high-viscosity ink is prevented from accumulating in the difference in level between the downstream portion 32 of the cover 30 and the nozzle surface 11x. This makes it easier to wipe off high-viscosity ink.

[0033] The downstream portion 32 of the cover 30 does not overlap the nozzle surface 11x in the vertical direction (see FIG. 3). If the downstream portion 32 of the cover 30 were provided with a portion that covers the nozzle surface 11x, the downstream portion 32 would protrude low from the nozzle surface 11x (the distance b would be small), so the thickness of that portion would need to be thin, making that portion more susceptible to damage. In this regard, in the present embodiment, the downstream portion 32 of the cover 30 does not have a portion that covers the nozzle surface 11x, so the above-mentioned damage can be suppressed.

[0034] The downstream portion 32 of the cover 30 is spaced apart in the wiping direction from the base portion 11x1 at the downstream end of the nozzle surface 11x in the wiping direction (see FIGS. 2 and 3). During the wiping process, the wiper 5 is generally positioned so as to form an acute angle with a portion of the nozzle surface 11x that is downstream of the wiper 5 in the wiping direction (see FIG. 3). In this case, if the downstream portion 32 is not spaced apart from the base portion 11x1 in the wiping direction, the wiper 5 will come into contact with the downstream portion 32 before passing through the base portion 11x1, and will not be able to wipe the ink off the base portion 11x1. In this regard, in this embodiment, the downstream portion 32 is spaced apart from the base portion 11x1 in the wiping direction, so the wiper 5 will come into contact with the downstream portion 32 after passing through the base portion 11x1, and will be able to wipe the ink off the base portion 11x1. In a configuration in which the downstream end of the nozzle surface 11x in the wiping direction has a base 11x1 and a protrusion 11x2, burrs X are likely to occur at the tip of the protrusion 11x2 but are unlikely to occur at the base 11x1. In this embodiment, the downstream portion 32 of the cover 30 contacts the tip of the protrusion 11x2 (the portion where burrs X are likely to occur) and is spaced apart from the base 11x1, so that even if the wiper 5 reaches the base 11x1, the wiper 5 is prevented from being damaged by the burrs X.

[0035] The acute angle θ formed between the wiper 5 and the nozzle surface 11x during the wiping process is 30 to 60 degrees (45 degrees in this embodiment) (see FIG. 3). If the angle θ exceeds 60 degrees, the wiper 5 is more likely to come into contact with the burr X that occurs at the downstream end of the nozzle surface 11x. If the angle θ is less than 30 degrees, ink is more likely to accumulate in the step between the downstream portion 32 of the cover 30 and the nozzle surface 11x. In this embodiment, by setting the angle θ to 30 to 60 degrees, both of the above problems can be suppressed. In other words, the effects of easily wiping high-viscosity ink and suppressing damage to the wiper 5 can be more effectively obtained.

[0036] During the wiping process, the acute angle θ between the wiper 5 and the nozzle surface 11x is 45 degrees, and the vertical distance b between the lower surface of the downstream section 32 and the nozzle surface 11x is smaller than the distance a in the wiping direction between the downstream section 32 and the base 11x1 (see FIG. 3). In this case, the requirement that the wiper 5 contacts the downstream section 32 after passing the base 11x1 can be reliably met. This makes it possible to more reliably wipe off the ink on the base 11x1.

[0037] The conveying direction is the same as the wiping direction (see FIG. 1). If the step between the downstream portion 32 of the cover 30 and the nozzle surface 11x (see FIG. 3) is large, the paper 9 will get caught on the step, and the paper 9 will likely be damaged or jammed. In this regard, in this embodiment, the step between the downstream portion 32 of the cover 30 and the nozzle surface 11x is low, so the paper 9 is less likely to get caught on the step, and the paper 9 is less likely to be damaged or jammed.

[0038] The cover 30 is made of epoxy resin, which allows the cover 30 to be produced inexpensively.

[0039] The gate remainder 30g of the cover 30 is located in a portion of the cover 30 other than the upstream portion 31 (in this embodiment, the downstream portion 32) (see FIG. 2). If the gate remainder 30g is located in the upstream portion 31, the wiper 5 may come into contact with the gate remainder 30g and be damaged. In this regard, in this embodiment, the gate remainder 30g is located in a portion of the cover 30 other than the upstream portion 31, so this problem can be prevented.

[0040] The liquid ejected from the nozzles 11n is an ink in which the pigment is coated with polymer particles (PP ink: Polymer Particle Ink). This ink dries quickly, and if it accumulates in the step between the downstream portion 32 of the cover 30 and the nozzle surface 11x, it can accumulate in the step and form large clumps. In this case, the clumps can reach the area of ​​the nozzle surface 11x where the nozzles 11n are formed, causing the nozzles 11n to become clogged. Furthermore, the clumps can cause unevenness in the nozzle surface 11x, which can prevent the nozzles 11n from being properly capped. In this regard, in this embodiment, the step between the downstream portion 32 of the cover 30 and the nozzle surface 11x is low (see FIG. 3), preventing ink from accumulating in the step, thereby alleviating this problem.

[0041] <Modification> Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design modifications are possible within the scope of the claims.

[0042] The downstream portion 32 of the cover 30 may be provided with a portion that covers the nozzle surface 11x.

[0043] The cover 30 is not limited to being made of epoxy resin, but may be made of any material (metal, etc.).

[0044] The acute angle θ formed between the wiper 5 and the nozzle surface 11x during the wiping process may be 30 to 60 degrees, and is not limited to 45 degrees.

[0045] The head 1 is not limited to a line type, but may be a serial type (a type in which liquid is ejected from nozzles onto a recording medium while moving in a scanning direction parallel to the paper width direction).

[0046] The recording medium is not limited to paper 9, but may be cloth, a substrate, or the like.

[0047] The liquid ejected from the nozzle 11n is not limited to ink in which the pigment is coated with polymer particles. Furthermore, the liquid is not limited to ink, and may be any liquid (for example, a treatment liquid that aggregates or precipitates components in the ink).

[0048] In the above embodiment, the movement mechanism moves the wiper 5 relative to the fixed head 1, but is not limited to this, and the head 1 may be moved relative to the fixed wiper 5.

[0049] The present invention is not limited to printers, but can also be applied to facsimiles, copiers, multifunction machines, etc. The present invention can also be applied to liquid ejection devices used for purposes other than image recording (for example, liquid ejection devices that eject conductive liquid onto a substrate to form a conductive pattern). [Explanation of symbols]

[0050] 4. Transport mechanism 5 wiper 5x wiper motor (movement mechanism) 10 Control Unit 11n nozzle 11x nozzle face 11x1 base 11x2 protrusion 30 Cover 31 Upper reaches 32 Downstream 100 Printer (liquid ejection device) θ angle

Claims

1. a nozzle surface in which a plurality of nozzles are opened, a wiper, a movement mechanism that moves the nozzle surface and the wiper relatively, and a control unit; the control unit controls the movement mechanism to perform a wiping process in which the wiper and the nozzle surface are moved relatively in a wiping direction parallel to the nozzle surface while the wiper is in contact with the nozzle surface; a cover that covers at least an upstream end of the nozzle surface in the wiping direction, the cover has an upstream portion that covers the upstream end of the nozzle surface and a downstream portion that is on the opposite side of the upstream portion with respect to the nozzle surface in the wiping direction, In a height direction perpendicular to the nozzle surface, the surface of the downstream portion is located between the nozzle surface and the surface of the upstream portion, A liquid ejection device, wherein the distance in the height direction between the surface of the downstream portion and the nozzle surface is 80 μm or less.

2. The liquid ejection device according to claim 1 , wherein the downstream portion does not have a portion that overlaps with the nozzle surface in the height direction.

3. a downstream end of the nozzle surface in the wiping direction includes a base portion and a protruding portion that protrudes from the base portion toward the downstream side in the wiping direction; The liquid ejection device according to claim 2 , wherein the downstream portion is spaced apart from the base portion in the wiping direction.

4. 4. The liquid ejection device according to claim 3, wherein the acute angle formed between the wiper and the nozzle surface during the wiping process is 30 to 60 degrees.

5. the angle is 45 degrees; The liquid ejection device according to claim 4 , wherein the distance in the height direction between the surface of the downstream portion and the nozzle surface is smaller than the distance in the wiping direction between the downstream portion and the base portion.

6. a conveying mechanism for conveying a recording medium; the control unit controls the transport mechanism to perform a transport process for transporting the recording medium in a transport direction so as to pass through a space facing the nozzle surface; 6. The liquid ejection device according to claim 1, wherein the transport direction is the same as the wiping direction.

7. 7. The liquid ejection device according to claim 1, wherein the cover is made of epoxy resin.

8. 8. The liquid ejection device according to claim 7, wherein the gate remainder of the cover is located in a portion of the cover other than the upstream portion.

9. 9. The liquid ejection device according to claim 1, wherein the liquid ejected from the plurality of nozzles is ink in which a pigment is coated with polymer particles.

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