Maintenance device and inkjet recording apparatus

Abstract

To manage an amount of humidifying media using a compact and simple configuration.SOLUTION: A maintenance device includes: a plurality of caps 72 that are provided for each ink jet head and mounted on nozzle surfaces of the ink jet heads; a plurality of supply units 92 that are provided for each cap 72, store humidifying media, generate humidified air WA by passing air A through the humidifying media, and supply the humidified air WA to the caps 72; one sub-tank 93 that stores the humidifying media, is opens to the atmosphere, and communicates with the plurality of supply units 92; and a replenishing unit (tank 93T, pump 93P) that replenishes the humidifying media into the sub-tank 93.SELECTED DRAWING: Figure 12

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 Art

[0002] In an inkjet recording apparatus that uses aqueous ink, there is a risk that moisture evaporates from the ink in the nozzles while printing is not being executed, increasing the viscosity and causing ejection failure or clogging. Therefore, conventionally, techniques for suppressing the evaporation of moisture from the ink in the nozzles have been studied. For example, Patent Document 1 describes an apparatus for supplying humidified air into a cap that covers the ejection surface (nozzle surface) of the head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a plurality of inkjet heads are provided, since the temperature of the inkjet heads is different for each inkjet head, it is desirable to control the temperature of the humidified air for each inkjet head. However, the apparatus described in Patent Document 1 includes one tank for storing water (humidifying medium) for a plurality of caps and one pump for supplying air to this tank, so the temperature of the humidified air cannot be controlled for each cap. If a tank, a pump, and a heater are provided for each cap, humidified air with controlled temperature can be generated for each cap. However, since the consumption rate of the humidifying medium varies depending on the temperature of the inkjet head, it is necessary to replenish the humidifying medium according to the consumption rate. If a sensor for detecting the amount of the humidifying medium and a pump for replenishing the humidifying medium are provided in each tank, replenishment according to the consumption rate becomes possible, but this leads to an increase in the size and complexity of the apparatus.

[0005] In view of the above circumstances, an object of the present invention is to manage the amount of a humidifying medium using a small and simple configuration.

Means for Solving the Problems

[0006] To solve the above problems, a maintenance apparatus according to the present invention includes a plurality of caps provided for each inkjet head and attached to the nozzle surface of the inkjet head, and a plurality of supply units provided for each cap, storing a humidifying medium, generating humidified air by passing air through the humidifying medium, and supplying the humidified air to the cap. The maintenance apparatus also includes one sub-tank that stores the humidifying medium, is open to the atmosphere, and communicates with the plurality of supply units, and a replenishing unit that replenishes the humidifying medium to the sub-tank.

[0007] The maintenance apparatus may further include a sensor for detecting the amount of the humidifying medium in the sub-tank and a control unit for controlling the replenishing unit so that the amount detected by the sensor is kept within a predetermined range.

[0008] An inkjet recording apparatus according to the present invention includes the inkjet head and any one of the above maintenance apparatuses.

Advantages of the Invention

[0009] According to the present invention, the amount of the humidifying medium can be managed using a small and simple configuration.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, an inkjet recording apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a perspective view showing the appearance of an image forming system 100. FIG. 2 is a front view schematically showing the internal configuration of the inkjet recording apparatus 1. FIG. 3 is a front view schematically showing the head unit 11 and the maintenance device 30. FIG. 4 is a plan view schematically showing the head unit 11 and the wipe unit 32. FIG. 5 is a plan view schematically showing the cap unit 31. FIG. 6 is a cross-sectional view showing the inkjet head 12. FIG. 7 is a front view showing the operation of the maintenance device 30. Hereinafter, the front side (front side) of the inkjet recording apparatus 1 will be the front side of the paper surface in FIG. 2, and the left and right directions will be described based on the direction of viewing the inkjet recording apparatus 1 from the front. In each figure, U, Lo, L, R, Fr, and Rr indicate up, down, left, right, front, and rear, respectively.

[0013] The image forming system 100 (see FIG. 1) includes a paper feeding device 110, an inkjet recording apparatus 1, a drying device 120, and a post-processing device 130. The paper feeding device 110 stores thousands of sheets and supplies the sheets to the inkjet recording apparatus 1. The inkjet recording apparatus 1 forms an image on the sheet by an inkjet method. The drying device 120 heats the sheet conveyed from the inkjet recording apparatus 1 to dry the ink. The post-processing device 130 performs post-processing such as punching, stapling, and folding on the sheet conveyed from the drying device 120.

[0014] The inkjet recording apparatus 1 (see FIG. 2) includes a rectangular parallelepiped main body housing 3. A conveyance unit 7 that adsorbs a sheet and conveys it in the Y direction is provided at the central part inside the main body housing 3. An image forming unit 6 that ejects ink to form an image is provided above the conveyance unit 7. A paper feed port 8 for introducing a sheet from a paper feed device 110 is provided on the right side surface of the main body housing 3. A discharge port 9 for discharging the sheet on which an image is formed to a drying device 120 is provided on the left side surface of the main body housing 3. Inside the main body housing 3, a conveyance path 10 is provided that extends from the paper feed port 8 through the gap between the conveyance unit 7 and the image forming unit 6 to the discharge port 9. A registration roller 18 is provided upstream of the conveyance unit 7 in the conveyance direction Y.

[0015] The conveyance unit 7 includes an endless conveyance belt 21 and a suction unit 24. The conveyance belt 21 has a number of ventilation holes (not shown) and is wound around a driving roller 25 and a driven roller 22. The upper surface of the suction unit 24 has a number of ventilation holes (not shown) and is in contact with the inner surface of the conveyance belt 21. By the suction unit 24 sucking air through the ventilation holes of the conveyance belt 21 and the ventilation holes of the suction unit 24, the sheet is adsorbed to the conveyance belt 21. The driving roller 25 is driven in the counterclockwise direction by a driving unit (not shown) including a motor and a reduction gear, so that the conveyance belt 21 rotates in the counterclockwise direction, and the sheet adsorbed to the conveyance belt 21 is conveyed in the Y direction.

[0016] The image forming unit 6 includes a plurality (four in this embodiment) of head units 11. The head unit 11 (see FIGS. 3 and 4) includes one or more (three in this embodiment) inkjet heads 12. Ink containers 20 filled with black, cyan, magenta, and yellow inks are respectively connected to each head unit 11.

[0017] The inkjet head 12 (see FIG. 6) includes a rectangular parallelepiped housing 12H with its 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 large 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 a discharge port 14A provided on a nozzle surface 14F which is the lower surface of the nozzle plate 14. The diaphragm 14V also serves as a part of the inner wall of the branch flow path 14B. A pressurizing element 14Z is provided on the diaphragm 14V. As the pressurizing element 14Z, a piezoelectric element, an electrostatic actuator, a heater, etc. are used. A drive circuit 12D for driving the pressurizing element 14Z is connected to the pressurizing element 14Z.

[0018] The control unit 2 (see FIG. 2) includes an arithmetic unit and a storage unit (not shown). The arithmetic 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 arithmetic unit performs various processes by reading and executing a control program stored in the storage unit. Note that the control unit 2 may be realized by an integrated circuit that does not use software.

[0019] 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 causes the display panel to display a screen representing an operation menu, status, etc. of the inkjet recording apparatus 1, and controls each part of the inkjet recording apparatus 1 according to operations detected by the touch panel and the keypad.

[0020] The basic image forming operation of the inkjet recording apparatus 1 is as follows. When an image forming job is input to the inkjet recording apparatus 1 from the display operation unit 19 or an external computer, etc., the paper feeding device 110 sends out a sheet onto the conveyance path 10 through the paper feed port 8, and the registration roller 18 whose rotation has been stopped corrects the skew of the sheet. When the registration roller 18 sends out the sheet to the conveyance unit 7 at a predetermined timing, the conveyance unit 7 sucks the sheet onto the conveyance belt 21 and conveys it in the Y direction. Ink is ejected from the inkjet head 12 onto the sheet to form an image. The sheet on which the image has been formed is discharged to the drying device 120 through the discharge port 9.

[0021] [Maintenance Device] 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, hereinafter, one head unit 11 and one maintenance device 30 provided to the right thereof will be described.

[0022] The head unit 11 includes a head base 11B (see FIGS. 3 and 4) that supports the inkjet head 12. Three inkjet heads 12 are provided on the head base 11B in a staggered manner.

[0023] The maintenance device 30 (see FIG. 3) is provided on the side (right side in this embodiment) of the head unit 11. The maintenance device 30 includes a cap unit 31 and a wipe unit 32.

[0024] [Cap Unit] The cap unit 31 (see FIGS. 3 and 5) includes the same number of caps 72 (three in this embodiment) as the inkjet heads 12 provided in the head unit 11. The three caps 72 are arranged in a staggered manner in the same way as the inkjet heads 12 and are supported by the frame body 71.

[0025] [Wipe Unit] The wipe unit 32 (see FIGS. 3 and 4) includes a waste liquid tray 81 and a cleaning member 82. The waste liquid tray 81 has the same number of recesses 81U as the inkjet heads 12 provided in the head unit 11. The plurality of recesses 81U are arranged in a staggered pattern, similar to the inkjet heads 12. The cleaning member 82 is provided in each of the recesses 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 wipe unit 32 is placed on the cap unit 31. The head unit 11 is provided with a cleaning liquid supply device 13 (see FIG. 6) that supplies cleaning liquid to the nozzle surface 14F.

[0026] [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 raises and lowers the head unit 11 between the image forming position and the retracted position. The image forming position (see FIG. 7(A)) is a position where the distance between the conveyance path 10 (the upper surface of the conveyance belt 21) where 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 retracted position (see FIG. 7(B)) is a position where the head unit 11 does not interfere with the wipe unit 32 when the cap slide device 34 described later is used to slide the cap unit 31 and the wipe unit 32. The retracted position is the upper limit position of the lifting range of the head unit 11.

[0027] [Cap slide device] The cap slide device 34 (see Fig. 5) is provided before and after the frame 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.

[0028] [Wiper lifting device] The wiper lifting device 35 (see Fig. 4) is provided before and after the waste liquid tray 81 of the wiper unit 32. The wiper lifting device 35 is composed of, for example, a ball screw, a belt drive device, etc. The wiper lifting device 35 raises and lowers the wiper unit 32 between a contact position (see Fig. 7(B)) where the waste liquid tray 81 contacts the cap 72 and a separation position (see Fig. 7(E)) where the waste liquid tray 81 is separated from the cap 72 by a predetermined distance.

[0029] 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 the I-I cross-section of Fig. 9. Fig. 11 is an exploded view showing the cap unit 31. Fig. 12 is a view showing the flow of the humidified air WA in the cap unit 31. Fig. 13 is a plan view showing the positions of the supply unit 92 and the recovery unit 94. Fig. 14 is a cross-sectional view showing the flow of the humidified air WA in the cap 72.

[0030] The maintenance device 30 according to this embodiment includes a plurality of caps 72 attached to the nozzle surface 14F of the inkjet head 12, an air supply port 72NA and an exhaust port 72EA provided in each of the plurality of caps 72, one recovery unit 94 that recovers air A from the exhaust ports 72EA of all the caps 72, and a plurality of supply units 92 provided for each cap 72 that supply humidified air WA, which is humidified air A recovered by the recovery unit 94, to the air supply port 72NA. The plurality of supply units 92 are arranged around one recovery unit 94. In each of the plurality of caps 72, the exhaust port 72EA is provided on the side of the recovery unit 94, and the air supply port 72NA is provided on the side of the supply unit 92.

[0031] The plurality of caps 72 include a first cap 721, a second cap 722, and a third cap 723. The first cap 721 and the second cap 722 are arranged along a predetermined direction (for example, the front-rear direction). The third cap 723 is arranged at an intermediate position between the first cap 721 and the second cap 722 in the predetermined direction and at a position different from the first cap 721 and the second cap 722 in a direction intersecting the predetermined direction. The exhaust port 72EA of the first cap 721 is provided on the side of the second cap 722, and the exhaust port 72EA of the second cap 722 is provided on the side of the first cap 721.

[0032] The maintenance device 30 is provided for each inkjet head 12 and includes a plurality of caps 72 attached to the nozzle surface 14F of the inkjet head 12, a plurality of supply units 92 provided for each cap 72 that store a humidifying medium WM, generate humidified air WA by passing air A through the humidifying medium WM, and supply the humidified air WA to the cap 72, one sub-tank 93 that stores the humidifying medium WM, is open to the atmosphere, and communicates with the plurality of supply units 92, and a replenishing unit (tank 93T, pump 93P) that replenishes the sub-tank 93 with the humidifying medium WM. Specifically, it is as follows.

[0033] [Cap] The cap 72 (see FIGS. 8 to 10) is formed in a box shape that opens upward. The cap 72 includes a substantially rectangular bottom portion 72B having a longitudinal direction in the front-rear direction, and side wall portions 72W that stand upright upward from the edges of the bottom portion 72B. The side wall portions 72W are formed of a flexible material such as rubber. An air supply port 72NA and an exhaust port 72EA are provided in the bottom portion 72B.

[0034] The three caps 72 are arranged in a staggered pattern. The first cap 721 is arranged on the right rear side of the frame body 71, the second cap 722 is arranged in front of the first cap 721, and the third cap 723 is arranged on the left side of the frame body 71. In the first cap 721 and the third cap 723, an exhaust port 72EA is provided on the front side, and an air supply port 72NA is provided on the rear side. In the second cap 722, an exhaust port 72EA is provided on the rear side, and an air supply port 72NA is provided on the front side. Note that in the second cap 722, an exhaust port 72EA may be provided on the front side and an air supply port 72NA may be provided on the rear side.

[0035] [Supply unit, recovery unit] Below the frame body 71 (see FIGS. 8, 11 to 13), the same number (three in this embodiment) of supply units 92 as the caps 72 and one recovery unit 94 are provided. Both the supply unit 92 and the recovery unit 94 are tanks for storing fluid. The supply unit 92 and the recovery unit 94 are supported by the frame body 91. Each supply unit 92 is arranged below the air supply port 72NA of each cap 72. The recovery unit 94 has a shape that overlaps all the exhaust ports 72EA in a plan view and is arranged below all the exhaust ports 72EA.

[0036] In other words, the three supply units 92 are arranged around one recovery unit 94. In each of the three caps 72, the exhaust port 72EA is provided on the side of the recovery unit 94, and the air supply port 72NA is provided on the side of the supply unit 92. Also, in other words, all the exhaust ports 72EA overlap the recovery unit 94 in the vertical direction, and in each of the plurality of caps 72, the air supply port 72NA overlaps the supply unit 92 in the vertical direction.

[0037] An air supply pipe 72N (see Fig. 10) that connects the cap 72 and the supply part 92 below it is connected to the air supply port 72NA of each cap 72. An exhaust pipe 72E that connects the cap 72 and the recovery part 94 is connected to the exhaust port 72EA of each cap 72. That is, three caps 72 communicate with the recovery part 94.

[0038] The air pump 95 is connected to the recovery part 94 by a recovery flow path 95E (see Figs. 8, 9, and 11), and is connected to all the supply parts 92 by a supply flow path 95N. The air pump 95 recovers the air A with a reduced water vapor pressure from the recovery part 94 via the recovery flow path 95E, and supplies the recovered air A to all the supply parts 92 via the supply flow path 95N (see Fig. 12).

[0039] All the supply parts 92 are connected to the sub-tank 93 via a communication pipe 92C (see Figs. 10, 11, and 12). A tank 93T and a pump 93P are connected to the sub-tank 93. A humidification medium WM (see Fig. 14) is stored in the tank 93T. The humidification medium WM is, for example, water, but any liquid containing water may be used. The pump 93P supplies the humidification medium WM from the tank 93T to the sub-tank 93.

[0040] A sensor 93S (see Figs. 8, 9, 11, and 12) for detecting the amount of the humidification medium WM in the sub-tank 93 is provided in the sub-tank 93. The sensor 93S detects, for example, the height of the liquid level in the sub-tank 93. A first heating part 92H (see Fig. 10) for heating the supply part 92 is provided in the supply part 92. A second heating part 72H for heating the cap 72 is provided in the cap 72. A sensor 92S for measuring the temperature inside the supply part 92 is provided in the supply part 92. A sensor 72S for measuring the temperature inside the cap 72 is provided in the cap 72. A sensor 94S for measuring at least one of the temperature and humidity inside the recovery part 94 is provided in the recovery part 94.

[0041] 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 positioned at the image forming position, and the cap unit 31 is positioned at the home position. The wipe unit 32 is placed on the cap unit 31. That is, the waste liquid tray 81 is in contact with the cap 72. The control unit 2 executes the following processes at a predetermined timing. The predetermined timing is, for example, the timing at which an increase in the viscosity of the ink in the nozzle 14N is expected, and specifically, when a period during which no image forming job is executed continues for a predetermined period.

[0042] 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)).

[0043] Next, after the control unit 2 forcibly discharges a predetermined amount of ink from the inkjet head 12, the cleaning liquid is supplied to the nozzle surface 14F, and the cleaning member 82 is slid along the nozzle surface 14F. Then, the ink remaining on the nozzle surface 14F is diluted with the cleaning liquid, and the waste liquid containing the ink and the cleaning liquid is scraped off by the cleaning member 82 and drops into the waste liquid tray 81.

[0044] 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 slide device 34 to slide the cap unit 31 and the wipe unit 32 to the home position (see FIG. 7(B)).

[0045] Next, the control unit 2 operates the wiper lifting device 35 to raise the wiper 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 wiper unit 32 is separated from the cap unit 31, the wiper unit 32 remains at the home position, and only the cap unit 31 slides to the maintenance position.

[0046] Next, the control unit 2 operates the head lifting device 11L to lower the head unit 11 until 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.

[0047] Next, the control unit 2 humidifies the inside of the cap 72. The control unit 2 monitors the measured value by the sensor 93S and maintains the height of the liquid level in the sub-tank 93 within a predetermined range. Specifically, when the measured value of the liquid level falls below the predetermined range, a predetermined amount of the humidifying medium WM is replenished from the tank 93T to the sub-tank 93 using the pump 93P. Since the sub-tank 93 communicates with the supply unit 92 through the communication pipe 92C, the height of the liquid level of the humidifying medium WM is uniform in the sub-tank 93 and all the supply units 92.

[0048] The air pump 95 (see Fig. 12) collects the air A with a reduced water vapor pressure from the collection unit 94 through the collection flow path 95E, and supplies the collected air A to all the supply units 92 through the supply flow path 95N. The end of the supply flow path 95N on the supply unit 92 side is disposed below the liquid level of the humidifying medium WM (see Fig. 14). Therefore, in the supply unit 92, the air A is blown into the humidifying medium WM, and bubbles B are generated. Before the bubbles B float to the liquid surface, the water vapor pressure of the bubbles B increases. Further, since the humidifying medium WM in the supply unit 92 is heated by the first heating unit 92H, water vapor is likely to be generated. Therefore, the space above the liquid level of the supply unit 92 is filled with the humidified air WA with an increased water vapor pressure, and the humidified air WA flows into the cap 72 through the air supply pipe 72N.

[0049] On the other hand, in the recovery unit 94, since air A is sucked by the air pump 95, a negative pressure is generated. Therefore, in the cap 72, an air flow of the humidified air WA from the air supply port 72NA to the exhaust port 72EA is generated. Further, since the humidified air WA supplied to the cap 72 is heated by the first heating unit 92H, convection occurs in 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, and an increase in the viscosity of the ink is suppressed.

[0050] In addition to the above control, the control unit 2 performs temperature control of each part. Specifically, each inkjet head 12 is provided with a sensor (not shown) that measures the temperature of the inkjet head 12 (for example, the temperature of the ink in the nozzle 14N). Also, as described above, the supply unit 92 is provided with a first heating unit 92H (see FIG. 10) that heats the supply unit 92. The cap 72 is provided with a second heating unit 72H that heats the cap 72. The supply unit 92 is provided with a sensor 92S that measures the temperature inside the supply unit 92. The cap 72 is provided with a sensor 72S that measures the temperature inside the cap 72. The recovery unit 94 is provided with a sensor 94S that measures at least one of the temperature and humidity inside the recovery unit 94.

[0051] The control unit 2 monitors the measured value by the sensor 92S, and controls the first heating unit 92H so that the temperature inside the supply unit 92 is equal to or higher than the temperature of the inkjet head 12. Also, the control unit 2 monitors the measured value by the sensor 72S, and controls the second heating unit 72H so that the temperature inside the cap 72 is equal to or higher than the temperature inside the supply unit 92. By this control, the temperature of the humidified air WA in the cap 72 is kept equal to or higher than the temperature of the inkjet head 12, and dew condensation in the cap 72 is prevented, so that evaporation of moisture from the ink in the nozzle 14N is suppressed.

[0052] When executing an image forming job, 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 wiper lifting device 35 to lower the wiper 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.

[0053] According to the maintenance device 30 according to the present embodiment described above, a plurality of caps 72 provided for each inkjet head 12 and attached to the nozzle surface 14F of the inkjet head 12, and a plurality of supply units 92 provided for each cap 72, storing the humidifying medium WM, generating humidified air WA by passing air A through the humidifying medium WM, and supplying the humidified air WA to the cap 72, a sub-tank 93 storing the humidifying medium WM, open to the atmosphere, and communicating with the plurality of supply units 92, and a replenishing unit (tank 93T, pump 93P) for replenishing the sub-tank 93 with the humidifying medium WM. According to this configuration, when the amount of the humidifying medium WM in the supply unit 92 decreases, the humidifying medium WM is replenished from the sub-tank 93 to the supply unit 92 due to the head difference with the sub-tank 93, and the liquid levels of the plurality of supply units 92 and the sub-tank 93 are equalized. By only managing the amount of the humidifying medium WM in the sub-tank 93, the amount of the humidifying medium WM in the plurality of supply units 92 can also be managed. Therefore, the amount of the humidifying medium WM can be managed using a small and simple configuration.

[0054] Further, according to the maintenance device 30 according to the present embodiment, a sensor 93S for detecting the amount of the humidifying medium WM in the sub-tank 93, and a control unit 2 for controlling the replenishing unit so that the amount detected by the sensor 93S is maintained within a predetermined range. According to this configuration, the amount of the humidifying medium WM in the sub-tank 93 and the plurality of supply units 92 can be controlled collectively.

[0055] Further, according to the inkjet recording apparatus 1 according to the present embodiment, a plurality of inkjet heads 12 and a maintenance device 30 are provided. According to this configuration, an increase in the viscosity of the ink in the nozzles 14N can be suppressed.

Explanation of Signs

[0056] 1 Inkjet recording apparatus 2 Control unit 12 Inkjet head 14F Nozzle surface 30 Maintenance device 72 Cap 92 Supply unit 93 Sub-tank 93P Pump (refilling unit) 93S Sensor 93T Tank (refilling unit)

Claims

1. a plurality of caps provided for each inkjet head and attached to nozzle faces of the inkjet heads; a plurality of supply units provided for each of the caps, each supply unit storing a humidifying medium, generating humidified air by passing air through the humidifying medium, and supplying the humidified air to the cap; a sub-tank that stores the humidifying medium, is open to the atmosphere, and is in communication with the plurality of supply units; a replenishing section that replenishing the humidifying medium to the sub-tank.

2. a sensor for detecting an amount of the humidification medium in the sub-tank; 2. The maintenance device according to claim 1, further comprising: a control unit that controls the replenishing unit so that the amount detected by the sensor is kept within a predetermined range.

3. A plurality of the inkjet heads; An inkjet recording apparatus comprising: the maintenance device according to claim 1 or 2.

Images