Maintenance device and inkjet recording device

Abstract

To prevent humidified air from directly hitting a nozzle surface and improve uniformity in humidification to the nozzle surface.SOLUTION: A maintenance device is provided with: a cap 72 that is attached to a nozzle surface 14F of an inkjet head 12; an air supply port 72NA and an air exhaust port 72EA formed in the cap 72; and a suppressing member 78, provided at least between the air supply port 72NA and the nozzle surface 14F, which has a first gap G1 between the air supply port 72NA and the member and has a second gap G2 between the nozzle surface 14F and the member. The suppressing member 78 is provided with a plurality of through-holes 78H1, 78H2 and 78H3 penetrating from the air supply port 72NA side toward the nozzle surface 14F side formed at positions not opposing to the air supply port 72NA, where diameters of the through-holes 78H1, 78H2 and 78H3 become larger as approaching the air exhaust port 72EA.SELECTED DRAWING: Figure 22

Description

[Technical field]

[0001] The present invention relates to a maintenance device for performing maintenance on an inkjet head, and an inkjet recording apparatus. [Background technology]

[0002] In an inkjet recording device that uses water-based ink, moisture evaporates from the ink in the nozzles while printing is not being performed, causing the viscosity to increase, which can lead to ejection failure and clogging. Therefore, techniques for suppressing the evaporation of moisture from the ink in the nozzles have been studied. For example, Patent Document 1 describes a device that supplies humidified air into a cap that covers the ejection surface (nozzle surface) of a head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-131064 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration described in Patent Document 1, the humidified air hits the nozzle surface directly, which can cause condensation on the nozzle surface and the ink can be pulled out of the nozzle by the condensation. In addition, the humidified air is supplied from an air inlet provided in the cap, but the farther away from the air inlet, the harder it is for the humidified air to reach the nozzle surface, causing the viscosity of the ink to increase. This causes problems such as uneven ejection performance and image density deviating from the image data.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In consideration of the above circumstances, an object of the present invention is to prevent humidified air from directly impinging on the nozzle surface and to improve the uniformity of humidification on the nozzle surface. [Means for solving the problem]

[0006] In order to solve the above problems, the maintenance device of the present invention comprises a cap that is attached to a nozzle face of an inkjet head, an air inlet and an exhaust port provided in the cap, and a suppression member that is provided at least between the air inlet and the nozzle face, having a first gap between the air inlet and a second gap between the nozzle face, the suppression member having a plurality of through holes that penetrate from the air inlet side to the nozzle face side at a position not facing the air inlet, and the diameter of the through holes becomes larger the closer to the exhaust port.

[0007] A through hole group including a plurality of the through holes may be provided at a plurality of locations along a direction from the air intake port side to the exhaust port side, and the diameter of the through hole in each through hole group may be larger the closer to the exhaust port.

[0008] The suppression member may be arranged along a direction from the air intake port side to the exhaust port side, and the multiple through holes may be arranged on both end sides of the suppression member in a width direction intersecting the direction from the air intake port side to the exhaust port side.

[0009] The plurality of through holes may extend from a bottom surface of the suppression member to a top surface, a side surface, or a ridge portion where the top surface and the side surface intersect.

[0010] The suppression member may be made of resin.

[0011] An inkjet recording apparatus according to the present invention includes the inkjet head and the maintenance device. Effect of the Invention

[0012] According to the present invention, it is possible to prevent humidified air from directly impinging on the nozzle surface, and to improve the uniformity of humidification on the nozzle surface. [Brief description of the drawings]

[0013] [Figure 1]1 is a perspective view showing the appearance of an image forming system according to a first embodiment of the present invention. [Diagram 2] 1 is a front view showing a schematic internal configuration of an inkjet recording apparatus according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a front view showing a schematic diagram of a head unit and a maintenance device according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a plan view illustrating a head unit and a wipe unit according to the first embodiment of the present invention. [Diagram 5] FIG. 2 is a plan view illustrating a cap unit according to the first embodiment of the present invention. [Figure 6] 1 is a cross-sectional view showing an ink-jet head according to a first embodiment of the present invention. [Figure 7] 5A to 5C are front views showing the operation of the maintenance device according to the first embodiment of the present invention. [Figure 8] FIG. 2 is a perspective view showing a cap unit according to the first embodiment of the present invention. [Figure 9] FIG. 2 is a plan view showing a cap unit according to the first embodiment of the present invention. [Figure 10] 10 is a cross-sectional view showing a cross section II of FIG. 9. [Figure 11] FIG. 2 is an exploded view showing the cap unit according to the first embodiment of the present invention. [Figure 12] 5A and 5B are diagrams illustrating the flows of air and humidified air within the cap unit according to the first embodiment of the present invention. [Figure 13] FIG. 2 is a plan view showing the positions of a humidification tank and a recovery tank according to the first embodiment of the present invention. [Figure 14] 3 is a cross-sectional view showing a flow of humidified air within the cap according to the first embodiment of the present invention. FIG. [Figure 15] 1 is a cross-sectional view showing a cap unit including a suppression member according to a first embodiment of the present invention. [Figure 16] 1 is a plan view showing a cap provided with a suppression member according to a first embodiment of the present invention. [Figure 17]FIG. 11 is a cross-sectional view showing a cap unit including a suppression member according to a second embodiment of the present invention. [Figure 18] FIG. 11 is a plan view showing a cap provided with a suppression member according to a second embodiment of the present invention. [Figure 19] FIG. 11 is a plan view showing a cap provided with a suppression member according to a third embodiment of the present invention. [Figure 20] FIG. 13 is a plan view showing a cap provided with a suppression member according to a fourth embodiment of the present invention. [Figure 21] FIG. 13 is a plan view showing a cap provided with a suppression member according to a fifth embodiment of the present invention. [Figure 22] FIG. 13 is a plan view showing a cap provided with a suppression member according to a sixth embodiment of the present invention. [Figure 23] FIG. 13 is a plan view showing a cap provided with a suppression member according to a seventh embodiment of the present invention. [Figure 24] 23 is a cross-sectional view showing the IV-IV cross section of FIG. 22. [Diagram 25] FIG. 13 is a cross-sectional view showing a first modified example of the sixth embodiment of the present invention. [Figure 26] FIG. 13 is a cross-sectional view showing a second modified example of the sixth embodiment of the present invention. [Figure 27] FIG. 13 is a cross-sectional view showing a cap unit including a suppression member according to an eighth embodiment of the present invention. [Figure 28] FIG. 13 is a plan view showing a cap provided with a suppression member according to an eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [First embodiment] An inkjet recording apparatus 1 according to a first embodiment of the present invention will now be described with reference to the drawings.

[0015] FIG. 1 is a perspective view showing the appearance of an image forming system 100. FIG. 2 is a front view showing the internal configuration of an inkjet recording device 1. FIG. 3 is a front view showing a head unit 11 and a maintenance device 30. FIG. 4 is a plan view showing a head unit 11 and a wipe unit 32. FIG. 5 is a plan view showing a cap unit 31. FIG. 6 is a cross-sectional view showing an inkjet head 12. FIG. 7 is a front view showing the operation of a maintenance device 30. In the following, the front side of the paper in FIG. 2 is the front side (front side) of the inkjet recording device 1, and the left and right directions are described based on the direction when the inkjet recording device 1 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr respectively indicate up, down, left, right, front, and rear.

[0016] The image forming system 100 (see FIG. 1) includes a paper feeder 110, an inkjet recording device 1, a drying device 120, and a post-processing device 130. The paper feeder 110 stores several thousand sheets and supplies the sheets to the inkjet recording device 1. The inkjet recording device 1 forms an image on the sheets using an inkjet method. The drying device 120 heats the sheets transported from the inkjet recording device 1 to dry the ink. The post-processing device 130 performs post-processing such as punching, stapling, and folding on the sheets transported from the drying device 120.

[0017] The inkjet recording device 1 (see FIG. 2) includes a rectangular parallelepiped main housing 3. A transport unit 7 that adsorbs and transports a sheet in the Y direction is provided in the center of the main housing 3. An imaging unit 6 that ejects ink to form an image is provided above the transport unit 7. A paper feed port 8 that introduces a sheet from a paper feed device 110 is provided on the right side of the main housing 3. A discharge port 9 that discharges the sheet on which an image has been formed to a drying device 120 is provided on the left side of the main housing 3. A transport path 10 is provided inside the main housing 3, which runs from the paper feed port 8 through a gap between the transport unit 7 and the imaging unit 6 to the discharge port 9. A registration roller 18 is provided upstream of the transport unit 7 in the transport direction Y.

[0018] The transport unit 7 includes an endless transport belt 21 and a suction unit 24. The transport belt 21 has many ventilation holes (not shown) and is wound around a drive roller 25 and a driven roller 22. The upper surface of the suction unit 24 has many ventilation holes (not shown) and is in contact with the inner surface of the transport belt 21. The suction unit 24 sucks air through the ventilation holes of the transport belt 21 and the ventilation holes of the suction unit 24, thereby adsorbing the sheet to the transport belt 21. The drive roller 25 is driven in the counterclockwise direction by a drive unit (not shown) including a motor and a reduction gear, so that the transport belt 21 rotates in the counterclockwise direction, and the sheet adsorbed to the transport belt 21 is transported in the Y direction.

[0019] The imaging unit 6 includes a plurality of (four in this embodiment) head units 11. Each head unit 11 (see FIGS. 3 and 4) includes one or more (three in this embodiment) inkjet heads 12. An ink container 20 filled with black, cyan, magenta, or yellow ink is connected to each head unit 11.

[0020] The inkjet head 12 (see FIG. 6) includes a rectangular parallelepiped housing 12H with the longitudinal direction being the front-rear direction, a nozzle plate 14 provided at the bottom of the housing 12H, and a socket 12S to which a pipe for supplying ink is connected. The nozzle plate 14 includes a number of nozzles 14N arranged in the front-rear direction. The nozzle 14N includes a branch flow path 14B branched from the downstream side of the socket 12S, and an ejection port 14A provided in a nozzle surface 14F, which is the lower surface of the nozzle plate 14. The vibration plate 14V also serves as a part of the inner wall of the branch flow path 14B. The vibration plate 14V is provided with a pressure element 14Z. A piezoelectric element, an electrostatic actuator, a heater, or the like is used as the pressure element 14Z. A drive circuit 12D for driving the pressure element 14Z is connected to the pressure element 14Z.

[0021] The control unit 2 (see FIG. 2) includes a calculation unit and a storage unit (not shown). The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit performs various processes by reading and executing control programs stored in the storage unit. The control unit 2 may be realized by an integrated circuit that does not use software.

[0022] A display operation unit 19 is provided on the upper part of the main body housing 3 (see Figs. 1 and 2). The display operation unit 19 includes a display panel, a touch panel laminated on the display panel, and a keypad (not shown). The control unit 2 displays a screen showing the operation menu and status of the inkjet recording device 1 on the display panel, and controls each part of the inkjet recording device 1 in response to operations detected by the touch panel and the keypad.

[0023] The basic image forming operation of the inkjet recording device 1 is as follows. When an image forming job is input to the inkjet recording device 1 from the display operation unit 19 or an external computer, the paper feeder 110 sends out a sheet to the transport path 10 through the paper feed port 8, and the registration rollers 18, whose rotation has been stopped, correct any skew of the sheet. When the registration rollers 18 send out the sheet to the transport unit 7 at a predetermined timing, the transport unit 7 attracts the sheet to the transport belt 21 and transports it in the Y direction. Ink is ejected from the inkjet head 12 onto the sheet, and an image is formed. The sheet on which the image has been formed is discharged to the drying device 120 through the discharge port 9.

[0024] [Maintenance equipment] Next, the maintenance device 30 will be described. Since the four head units 11 have the same configuration, and the four maintenance devices 30 have the same configuration, the following describes one head unit 11 and one maintenance device 30 provided to the right of it.

[0025] The head unit 11 includes a head base 11B (see FIGS. 3 and 4) that supports the inkjet heads 12. Three inkjet heads 12 are provided in a staggered manner on the head base 11B.

[0026] The maintenance device 30 (see FIG. 3) is provided on the side (the right side in this embodiment) of the head unit 11. The maintenance device 30 includes a cap unit 31 and a wipe unit 32.

[0027] [Cap Unit] The cap unit 31 (see FIGS. 3 and 5) has caps 72 in the same number (three in this embodiment) as the inkjet heads 12 included in the head unit 11. The three caps 72 are arranged in a staggered manner similar to the inkjet heads 12, and are supported by a frame 71. Two caps 72 are arranged in front and rear to the right of the center in the left-right direction of the frame 71, and one cap 72 is arranged on the left side. The one left cap 72 is arranged in the middle in the front-rear direction between the two caps 72 on the right side.

[0028] [Wipe unit] The wiping unit 32 (see FIGS. 3 and 4) includes a waste liquid tray 81 and a cleaning member 82. The waste liquid tray 81 includes recesses 81U in the same number as the inkjet heads 12 included in the head unit 11. The recesses 81U are arranged in a staggered manner, similar to the inkjet heads 12. The cleaning member 82 is provided in each recess 81U. The cleaning member 82 is, for example, a blade. The waste liquid tray 81 includes a drive unit (not shown) that slides the cleaning member 82 along the nozzle surface 14F. The waste liquid tray 81 is placed on a plurality of caps 72. In other words, the wiping unit 32 is placed on the cap unit 31. The head unit 11 includes a cleaning liquid supplying device 13 (see FIG. 6) that supplies cleaning liquid to the nozzle surface 14F.

[0029] [Head lifting device] The head lifting device 11L (see FIG. 4) is provided in front of and behind the head base 11B. The head lifting device 11L is composed of, for example, a ball screw, a belt drive device, etc. The head lifting device 11L lifts and lowers the head unit 11 between an image forming position and a retreated position. The image forming position (see FIG. 7(A)) is a position where the distance between the conveying path 10 (the upper surface of the conveying belt 21) through which the sheet is conveyed and the nozzle surface 14F is a predetermined distance suitable for image formation. The image forming position is the lower limit position of the lifting range of the head unit 11 by the head lifting device 11L. The retreated position (see FIG. 7(B)) is a position where the head unit 11 does not interfere with the wiping unit 32 when the cap unit 31 and the wiping unit 32 are slid using the cap slide device 34 described later. The retreated position is the upper limit position of the lifting range of the head unit 11.

[0030] [Cap slide device] The cap slide device 34 (see FIG. 5) is provided in front of and behind the frame body 71 of the cap unit 31. The cap slide device 34 is composed of, for example, a ball screw, a belt drive device, etc. The cap slide device 34 slides the cap unit 31 to a home position and a maintenance position. The home position (see FIG. 7(A)) is a position to the right of the head unit 11 located at the image forming position. The maintenance position (see FIG. 7(F)) is a position below the head unit 11 located at the retracted position.

[0031] [Wipe lifting device] The wipe lifting device 35 (see FIG. 4) is provided in front of and behind the waste liquid tray 81 of the wipe unit 32. The wipe lifting device 35 is formed, for example, of a ball screw, a belt drive device, etc. The wipe lifting device 35 lifts and lowers the wipe unit 32 to a contact position (see FIG. 7(B)) where the waste liquid tray 81 contacts the cap 72, and a separated position (see FIG. 7(E)) where the waste liquid tray 81 is separated a predetermined distance from the cap 72.

[0032] Next, the configuration of the cap unit 31 will be described in detail. Fig. 8 is a perspective view showing the cap unit 31. Fig. 9 is a plan view showing the cap unit 31. Fig. 10 is a cross-sectional view showing cross section II of Fig. 9. Fig. 11 is an exploded view showing the cap unit 31. Fig. 12 is a diagram showing the flow of air A and humidified air WA in the cap unit 31. Fig. 13 is a plan view showing the positions of the humidification tank 92 and the recovery tank 94. Fig. 14 is a cross-sectional view showing the flow of humidified air WA in the cap 72.

[0033] [cap] The cap 72 (see Figs. 8 to 10) is formed in a box shape that opens upward. The cap 72 has a bottom 72B that is roughly rectangular with the longitudinal direction being the front-rear direction, and a side wall 72W that stands upright upward from the edge of the bottom 72B. The side wall 72W is formed of a flexible material such as rubber. The bottom 72B is provided with an air inlet 72NA and an exhaust port 72EA. The right rear and left caps 72 have an air inlet 72NA on the rear side and an exhaust port 72EA on the front side. The right front cap 72 has an air inlet 72NA on the front side and an exhaust port 72EA on the rear side.

[0034] [Humidification tank, recovery tank] Below the frame 71 (see FIGS. 8, 11 to 13), there are provided humidification tanks 92, the same number as the caps 72 (three in this embodiment), and one recovery tank 94. The humidification tanks 92 and the recovery tank 94 are supported by the frame 91. Each humidification tank 92 is disposed below the air supply port 72NA of each cap 72. The recovery tank 94 has a shape that encompasses all the exhaust ports 72EA in a plan view, and is disposed below all the exhaust ports 72EA.

[0035] An air intake pipe 72N (see FIG. 10) that connects the cap 72 to the humidification tank 92 below is connected to the air intake port 72NA of each cap 72. An exhaust pipe 72E that connects the cap 72 to the collection tank 94 is connected to the exhaust port 72EA of each cap 72. In other words, the collection tank 94 is connected to three exhaust pipes 72E.

[0036] The air pump 95 is connected to the recovery tank 94 by a recovery passage 95E (see FIGS. 8, 9 and 11), and is connected to all of the humidification tanks 92 by a supply passage 95N. The air pump 95 recovers air A from the recovery tank 94 via the recovery passage 95E, and supplies the recovered air A to all of the humidification tanks 92 via the supply passage 95N (see FIG. 12).

[0037] All the humidification tanks 92 are connected to the humidification subtank 93 via a communication pipe 92C (see Figs. 10, 11, and 12). A humidification medium tank 93T and a humidification medium pump 93P are connected to the humidification subtank 93. The humidification medium tank 93T stores the humidification medium WM (see Fig. 14). The humidification medium WM is, for example, water. The humidification medium pump 93P supplies the humidification medium WM from the humidification medium tank 93T to the humidification subtank 93. The humidification subtank 93 is provided with a liquid level sensor 93S (see Figs. 8, 9, and 11) that detects the liquid level in the humidification subtank 93. The humidification tank 92 is provided with a heater 92H (see Fig. 10) that heats the humidification medium WM.

[0038] Next, the basic operation of the maintenance device 30 will be described. In the initial state (see FIG. 7(A)), the head unit 11 is located at the image forming position, and the cap unit 31 is located at the home position. The wipe unit 32 is placed on the cap unit 31. In other words, the waste liquid tray 81 is in contact with the cap 72. The control unit 2 executes the process shown below at a predetermined timing. The predetermined timing is, for example, a timing when the viscosity of the ink in the nozzle 14N is expected to increase, and specifically, when a period in which an image forming job is not executed continues for a predetermined period of time.

[0039] First, the control unit 2 operates the head lifting device 11L to raise the head unit 11 to the retracted position (see FIG. 7(B)). Next, the control unit 2 operates the cap slide device 34 to slide the cap unit 31 to the maintenance position (see FIG. 7(C)). At this time, since the wipe unit 32 is placed on the cap unit 31, the wipe unit 32 also slides to the maintenance position together with the cap unit 31. Next, the control unit 2 operates the head lifting device 11L to lower the head unit 11 to a height at which the nozzle surface 14F contacts the cleaning member 82 (see FIG. 7(D)).

[0040] Next, the control unit 2 forcibly ejects a predetermined amount of ink from the inkjet head 12, and then supplies cleaning liquid to the nozzle surface 14F and slides the cleaning member 82 along the nozzle surface 14F. Then, the ink remaining on the nozzle surface 14F is diluted with the cleaning liquid, and waste liquid containing the ink and cleaning liquid is scraped off by the cleaning member 82 and falls into the waste liquid tray 81.

[0041] Next, the control unit 2 operates the head lifting device 11L to raise the head unit 11 to the retracted position (see FIG. 7(C)). Next, the control unit 2 operates the cap sliding device 34 to slide the cap unit 31 and the wipe unit 32 to the home position (see FIG. 7(B)).

[0042] Next, the control unit 2 operates the wipe lifting device 35 to raise the wipe unit 32 to the separated position (see FIG. 7(E)). Next, the control unit 2 operates the cap slide device 34 to slide the cap unit 31 to the maintenance position (see FIG. 7(F)). At this time, since the wipe unit 32 is separated from the cap unit 31, the wipe unit 32 remains in the home position, and only the cap unit 31 slides to the maintenance position.

[0043] Next, the control unit 2 operates the head lifting device 11L to lower the head unit 11 to a height where the nozzle surface 14F contacts the cap 72 (see FIG. 7(G)). In this way, the cap 72 is attached to the nozzle surface 14F.

[0044] Next, the control unit 2 humidifies the inside of the cap 72. The control unit 2 monitors the measurement value by the liquid level sensor 93S and maintains the liquid level in the humidification subtank 93 within a predetermined range. Specifically, when the measurement value of the liquid level falls below the predetermined range, a predetermined amount of humidification medium WM is replenished from the humidification medium tank 93T to the humidification subtank 93 using the humidification medium pump 93P. Because the humidification subtank 93 is in communication with the humidification tank 92 by the communication pipe 92C, the liquid level of the humidification medium WM in the humidification subtank 93 and all of the humidification tanks 92 becomes uniform.

[0045] The air pump 95 (see FIG. 12) collects air A from the collection tank 94 through the collection flow path 95E, and supplies the collected air A to all the humidification tanks 92 through the supply flow path 95N. The end of the supply flow path 95N on the humidification tank 92 side is disposed below the liquid level of the humidification medium WM (see FIG. 14). Therefore, in the humidification tank 92, the air A is blown into the humidification medium WM, and bubbles B are generated. The water vapor pressure of the bubbles B increases before the bubbles B rise to the liquid level. In addition, the humidification medium WM in the humidification tank 92 is heated by the heater 92H, so that water vapor is easily generated. Therefore, the space above the liquid level in the humidification tank 92 is filled with humidified air WA with increased water vapor pressure, and the humidified air WA flows into the cap 72 through the air supply pipe 72N.

[0046] Meanwhile, in the recovery tank 94, air A is sucked in by the air pump 95, generating a negative pressure. As a result, an airflow of humidified air WA flows from the air supply port 72NA to the air exhaust port 72EA inside the cap 72. Also, since the humidified air WA heated by the heater 92H is supplied to the cap 72, convection occurs inside the cap 72, and the high-temperature humidified air WA is supplied to the nozzle surface 14F. In this way, the humidified air WA comes into contact with the ink in the nozzle 14N, suppressing an increase in the viscosity of the ink.

[0047] When an image forming job is to be executed, the control unit 2 operates the head lifting device 11L to raise the head unit 11 to the retracted position (see FIG. 7(F)), operates the cap slide device 34 to slide the cap unit 31 to the home position (see FIG. 7(E)), and operates the wipe lifting device 35 to lower the wipe unit 32 to the contact position (see FIG. 7(B)). Then, the control unit 2 operates the head lifting device 11L to lower the head unit 11 to the image forming position, and executes the image forming job.

[0048] Incidentally, the humidified air WA that flows into the cap 72 through the air supply pipe 72N rises toward the nozzle surface 14F, so that the humidified air WA hits the nozzle surface 14F directly, which may cause condensation to form on the nozzle surface 14F and cause the ink to be pulled by the condensation and come out of the nozzles 14N. The ink that falls may accumulate inside the cap 72 and impede the flow of the humidified air WA or clog the air supply pipe 72N.

[0049] Therefore, the maintenance device 30 according to this embodiment is provided with a suppression member 73. Fig. 15 is a cross-sectional view showing a cap unit 31 provided with the suppression member 73. Fig. 16 is a plan view showing a cap 72 provided with the suppression member 73. Fig. 15 is a cross-sectional view taken along line II-II in Fig. 16.

[0050] The maintenance device 30 according to this embodiment includes a cap 72 attached to the nozzle surface 14F of the inkjet head 12, an air supply port 72NA provided in the cap 72, and a suppression member 73 provided at least between the air supply port 72NA and the nozzle surface 14F, having a first gap G1 between the air supply port 72NA and the nozzle surface 14F, and having a second gap G2 between the air supply port 72NA and the nozzle surface 14F. Specifically, it is as follows.

[0051] The suppression member 73 is provided above the air supply port 72NA. The suppression member 73 is a plate-shaped member whose thickness direction is the up-down direction, and is made of resin. The suppression member 73 is supported by a support 73P provided on the bottom 72B of the cap 72. The dimensions of the suppression member 73 in the front-rear and left-right directions are larger than those of the air supply port 72NA. The suppression member 73 is provided so as to cover at least the entire air supply port 72NA in a plan view. A first gap G1 is provided between the air supply port 72NA and the lower surface of the suppression member 73. A second gap G2 is provided between the nozzle surface 14F and the upper surface of the suppression member 73.

[0052] A portion of the humidified air WA1 (see FIG. 15) that flows into the cap 72 from the air supply port 72NA flows forward from the first gap G1 and is sucked into the exhaust port 72EA. Another portion of the humidified air WA2 flows from the first gap G1 to the rear of the suppression member 73, turns around to the second gap G2, flows forward from the second gap G2, and is sucked into the exhaust port 72EA. Another portion of the humidified air WA3 (see FIG. 16) flows forward from the spaces on the left and right of the suppression member 73 and is sucked into the exhaust port 72EA. In other words, above the air supply port 72NA, the humidified air WA flows along the lower and upper surfaces of the suppression member 73, so the humidified air WA does not directly hit the nozzle 14 surface F above the air supply port 72NA. As a result, the occurrence of condensation on the nozzle surface 14F is suppressed, and it is possible to prevent the ink from being drawn by the condensation and coming out of the nozzle 14N.

[0053] The reason why the suppression member 73 is made of resin is as follows. There is a risk of condensation occurring on the suppression member 73 as the suppression member 73 removes heat from the humidified air WA. In particular, in this embodiment, condensation is more likely to occur because the heater 92H is provided in the humidification tank 92 to increase the amount of water vapor in the humidified air WA. When condensation occurs, the water vapor pressure of the humidified air WA decreases, and the humidification effect on the ink in the nozzles 14N decreases. In order to suppress condensation, it is desirable to form the suppression member 73 from a material with low thermal conductivity. In general, resin has a lower thermal conductivity than metal, and is therefore a suitable material for the suppression member 73.

[0054] The maintenance device 30 according to the present embodiment described above includes a cap 72 attached to the nozzle surface 14F of the inkjet head 12, an air supply port 72NA provided in the cap 72, and a suppression member 73 provided at least between the air supply port 72NA and the nozzle surface 14F, having a first gap G1 between the air supply port 72NA and the nozzle surface 14F, and having a second gap G2 between the air supply port 72NA and the nozzle surface 14F. According to the present embodiment, it is possible to prevent the humidified air WA from directly hitting the nozzle surface 14F.

[0055] Furthermore, in the maintenance device 30 according to this embodiment, the suppression member 73 is made of resin. According to this embodiment, it is possible to suppress condensation of the humidified air WA.

[0056] Moreover, the inkjet recording apparatus according to this embodiment includes the inkjet head 12 and the maintenance device 30. According to this embodiment, an increase in the viscosity of the ink inside the nozzles 14N of the inkjet head 12 can be suppressed.

[0057] [Second embodiment] Fig. 17 is a cross-sectional view showing a cap unit 31 including a suppressing member 74 according to the second embodiment. Fig. 18 is a plan view showing a cap 72 including a suppressing member 74 according to the second embodiment.

[0058] The suppression member 74 is provided along a direction from the intake port 72NA side to the exhaust port 72EA side. Specifically, the suppression member 74 is a rectangular plate-like member whose longitudinal direction is from the intake port 72NA side to the exhaust port 72EA side. The suppression member 74 is supported by a support 74P provided on the bottom 72B of the cap 72. The rear end of the suppression member 74 is disposed above the intake port 72NA. The front end of the suppression member 74 is located rearward of the exhaust port 72EA. A first gap G1 is provided between the intake port 72NA and the lower surface of the suppression member 74. A second gap G2 is provided between the nozzle surface 14F and the upper surface of the suppression member 74.

[0059] The suppression member 74 has through holes 74H penetrating from the air supply port 72NA side to the nozzle surface 14F side at positions not facing the air supply port 72NA. The through holes 74H are provided at multiple locations (three locations in this embodiment) along the direction from the air supply port 72NA side to the exhaust port 72EA side.

[0060] A portion of the humidified air WA1 (see FIG. 15) that flows into the cap 72 from the air supply port 72NA flows forward through the first gap G1 and is drawn into the exhaust port 72EA. Another portion of the humidified air WA2 flows from the first gap G1 to the rear of the suppression member 74, turns around to the second gap G2, flows forward through the second gap G2, and is drawn into the exhaust port 72EA. Another portion of the humidified air WA3 (see FIG. 16) flows forward through the spaces on the left and right of the suppression member 73 and is drawn into the exhaust port 72EA. In other words, the humidified air WA flows along the lower and upper surfaces of the suppression member 74 over a wider range than in the above embodiment, so that the humidified air WA does not directly impinge on the nozzle surface 14F over a wider range than in the above embodiment.

[0061] Furthermore, a portion WA4 of the humidified air flowing through the first gap G1 to the exhaust port 72EA flows from the first gap G1 to the second gap G2 through the through-hole 74H, thereby compensating for a shortage of humidified air WA supplied by the suppression member 74. Furthermore, the humidified air WA is also supplied through the through-hole 74H to the nozzle surface 14F away from the intake port 72NA, improving the uniformity of humidification of the nozzle surface 14F.

[0062] According to the maintenance device 30 of this embodiment described above, the cap 72 includes the exhaust port 72EA, and the suppression member 74 is provided along the direction from the air supply port 72NA side to the exhaust port 72EA side. According to this embodiment, it is possible to prevent the humidified air WA from directly hitting the nozzle surface 14F over a wide range along the direction from the air supply port 72NA side to the exhaust port 72EA side.

[0063] Furthermore, according to the maintenance device 30 of this embodiment, the suppression member 74 is provided with a through-hole 74H that penetrates from the air supply port 72NA side to the nozzle surface 14F side at a position not facing the air supply port 72NA. According to this embodiment, it is possible to compensate for a shortage of the supply of humidified air WA by the suppression member 74.

[0064] Furthermore, according to the maintenance device 30 of this embodiment, the cap 72 includes the exhaust port 72EA, and the through holes 74H are provided at a plurality of locations along the direction from the intake port 72NA side to the exhaust port 72EA side. According to this embodiment, it is possible to improve the uniformity of humidification of the nozzle surface 14F.

[0065] [Third embodiment] 19 is a plan view showing a cap 72 including a suppressing member 75 according to a third embodiment. A maintenance device 30 according to this embodiment includes a cap 72 attached to a nozzle surface 14F of an inkjet head 12, an air inlet 72NA and an exhaust port 72EA provided in the cap 72, and a suppressing member 75 provided at least between the air inlet 72NA and the nozzle surface 14F, having a first gap G1 between the air inlet 72NA and the nozzle surface 14F and having a second gap G2 between the nozzle surface 14F, and the suppressing member 75 includes a plurality of through holes 75H penetrating from the air inlet 72NA side to the nozzle surface 14F side at a position not facing the air inlet 72NA, the plurality of through holes 75H have the same diameter, and the closer to the exhaust port 72EA, the higher the density of the through holes 75H.

[0066] Specifically, through-hole groups 75Hs including a plurality of through-holes 75H are provided at a plurality of locations along a direction from the intake port 72NA side toward the exhaust port 72EA side, and the distance between adjacent through-hole groups 75Hs becomes shorter as the group is closer to the exhaust port 72EA. Note that, in the illustrated example, the number of through-holes 75H included in the through-hole group 75Hs is five, but the number of through-holes 75H included in the through-hole group 75Hs may be any number.

[0067] According to this embodiment, the uniformity of humidification of the nozzle surface 14F can be improved compared to a case where the density of the through holes 75H is uniform. Also, according to this embodiment, the uniformity of humidification of the nozzle surface 14F can be improved compared to a case where a plurality of through hole groups 75Hs are provided at equal intervals in the direction from the intake port 72NA side to the exhaust port 72EA side.

[0068] [Fourth embodiment] 20 is a plan view showing a cap 72 equipped with a suppression member 76 according to the fourth embodiment. In the maintenance device 30 according to the present embodiment, through-hole groups 76Hs1 to 4 including a plurality of through-holes 76H are provided at a plurality of locations along a direction from the intake port 72NA side to the exhaust port 72EA side, and the number of through-holes 76H in each of the through-hole groups 76Hs1 to 4 increases the closer to the exhaust port 72EA.

[0069] In the illustrated example, the through hole groups 76Hs1 to 4 include 5, 9, 14, and 18 through holes 76H, respectively. In the illustrated example, when the through hole groups 76Hs1 to 4 include more than 5 through holes 76H, the through holes 76H are arranged in a staggered pattern, but the through holes 76H may be arranged in any manner in the through hole groups 76Hs1 to 4. In the illustrated example, the distance between the adjacent through hole groups 75Hs1 to 4 is shorter as the group is closer to the exhaust port 72EA, but the distance between the adjacent through hole groups 76Hs1 to 4 may be constant. According to this embodiment, the uniformity of humidification of the nozzle surface 14F can be improved compared to when the number of through holes 76H included in the multiple through hole groups 76Hs1 to 4 is the same.

[0070] [Fifth embodiment] 21 is a plan view showing a cap 72 equipped with a suppression member 77 according to a fifth embodiment. Although the arrangement of the through holes 77H differs from that of the third and fourth embodiments, in this embodiment, the multiple through holes 77H have the same diameter, and the closer to the exhaust port 72EA, the higher the density of the through holes 77H. This embodiment also improves the uniformity of humidification of the nozzle surface 14F compared to the case where the density of the through holes 77H is uniform.

[0071] [Sixth embodiment] 22 is a plan view showing a cap 72 including a suppressing member 78 according to a sixth embodiment. A maintenance device 30 according to this embodiment includes a cap 72 attached to a nozzle surface 14F of an inkjet head 12, an air inlet 72NA and an exhaust port 72EA provided in the cap 72, and a suppressing member 78 provided at least between the air inlet 72NA and the nozzle surface 14F, having a first gap G1 between the air inlet 72NA and the nozzle surface 14F and having a second gap G2 between the air inlet 72NA and the nozzle surface 14F, and the suppressing member 78 includes a plurality of through holes 78H1 to 3 penetrating from the air inlet 72NA side to the nozzle surface 14F side at a position not facing the air inlet 72NA, and the diameters of the through holes 78H1 to 3 are larger the closer to the exhaust port 72EA.

[0072] Specifically, through-hole groups 78H1s, 78H2s, 78H3s including a plurality of through-holes 78H1, 78H2, 78H3 are provided at a plurality of locations along a direction from the intake port 72NA side to the exhaust port 72EA side, and the diameters of the through-holes 78H1, 78H2, 78H3 in each of the through-hole groups 78H1s, 78H2s, 78H3s are larger the closer to the exhaust port 72EA. According to this embodiment, the uniformity of humidification of the nozzle surface 14F can be improved compared to a case in which the diameters of the through-holes 78H1, 78H2, 78H3 in each of the through-hole groups 78H1s, 78H2s, 78H3s are the same.

[0073] Fig. 24 is a cross-sectional view showing the IV-IV cross section of Fig. 22. The suppression member 78 is provided along a direction from the air supply port 72NA side to the exhaust port 72EA side, and the plurality of through holes 78H1 to 3 are provided on both end sides of the suppression member 78 in a width direction intersecting with a direction from the air supply port 72NA side to the exhaust port 72EA side. The plurality of through holes 78H1 to 3 penetrate the suppression member 78 from the bottom surface to the top surface. According to this embodiment, the uniformity of humidification in the width direction on the nozzle surface 14F can be improved compared to a case where the through holes 78H1 to 3 are provided in the center in the width direction.

[0074] 25 is a cross-sectional view showing a first modified example of the sixth embodiment. A plurality of through holes 78H1 to 78H3 penetrate from the bottom surface to the side surface of the suppression member 78. This embodiment also makes it possible to improve the uniformity of humidification in the width direction of the nozzle surface 14F.

[0075] 26 is a cross-sectional view showing a second modified example of the sixth embodiment. A plurality of through holes 78H1 to 3 penetrate from the bottom surface of the suppression member 78 to the ridge portion where the top surface and the side surface intersect. This embodiment also makes it possible to improve the uniformity of humidification in the width direction of the nozzle surface 14F.

[0076] [Seventh embodiment] 23 is a plan view showing a cap 72 equipped with a suppression member 79 according to the seventh embodiment. In this embodiment, the diameters of the through holes 79H1, 79H2, ..., 79H9 are gradually increased toward the exhaust port 72EA. This embodiment also makes it possible to improve the uniformity of humidification of the nozzle surface 14F.

[0077] [Eighth embodiment] Fig. 27 is a cross-sectional view showing a cap unit 31 including a suppression member 74 according to the eighth embodiment. Fig. 28 is a plan view showing a cap 72 including a suppression member 74 according to the eighth embodiment. In the second embodiment (see Fig. 17), the end of the suppression member 74 on the exhaust port 72EA side is located rearward of the exhaust port 72EA, which causes a problem that the humidified air WA is difficult to supply to the region R in front of the end of the suppression member 74 on the exhaust port 72EA side on the nozzle surface 14F.

[0078] Therefore, in this embodiment, the end of the suppression member 74 on the exhaust port 72EA side faces the exhaust port 72EA. According to this embodiment, the humidified air WA flowing forward through the second gap G2 turns from the front of the suppression member 74 around the first gap G1 and is sucked into the exhaust port 72EA, so that the humidified air WA can also be supplied to the nozzle surface 14F on the exhaust port 72EA side. Therefore, according to this embodiment, it is possible to improve the uniformity of humidification of the nozzle surface 14F. [Explanation of symbols]

[0079] 1 Inkjet recording device 12 Inkjet head 14F Nozzle surface 30 Maintenance Equipment 72 Cap 72EA Exhaust port 72NA air supply port 73 Restraining member 73H through hole G1 1st gap G2 2nd gap

Claims

1. A cap attached to a nozzle surface of the inkjet head; An air inlet and an air outlet provided in the cap; a suppression member that is provided at least between the air supply port and the nozzle surface, the suppression member having a first gap between the air supply port and the nozzle surface, and a second gap between the nozzle surface and the suppression member; The suppression member is a plurality of through holes are provided at positions not facing the air inlet, the through holes penetrating from the air inlet side to the nozzle surface side; A maintenance device, characterized in that the diameter of the through hole is larger the closer it is to the exhaust port.

2. a through-hole group including a plurality of the through-holes is provided at a plurality of locations along a direction from the air intake port side to the air exhaust port side, 2. The maintenance device according to claim 1, wherein the diameter of the through holes in each of the through hole groups is larger the closer to the exhaust port.

3. The suppression member is provided along a direction from the air supply port side to the air exhaust port side, 3. The maintenance device according to claim 1, wherein the plurality of through holes are provided on both end sides of the suppression member in a width direction intersecting a direction from the air supply port side to the air exhaust port side.

4. The maintenance device according to claim 3 , wherein the plurality of through holes penetrate from a bottom surface of the suppressing member to an upper surface, a side surface, or a ridge portion where the upper surface and the side surface intersect.

5. The maintenance device according to claim 1 , wherein the suppressing member is made of resin.

6. The inkjet head; An inkjet recording apparatus comprising: the maintenance device according to claim 1 .

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