JP2018020517A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer which can reduce the cleaning insufficiency of a cap of an ink jet head.SOLUTION: An ink jet printer includes: an ink jet head 31 which has a nozzle for discharging ink; a cap 51 which contacts the ink jet head 31 and covers a nozzle; a pump 42 which is connected to a suction hole provided in the cap 51 via a suction pipe 53 and suctions the contents from the space in the cap 51; a cleaning liquid tank 47 which stores cleaning liquid; and a control unit which performs control so as to immerse the cap 51 in the cleaning liquid in the cleaning liquid tank 47 at the cleaning of the cap 51, drive the pump 42 in such the state that the cap 51 is immersed in the cleaning liquid, suction the cleaning liquid from the suction hole to the suction pipe 53, then drive the pump 42 inversely from the time of suction, and discharge the cleaning liquid suctioned to the suction pipe 53 from the suction hole.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ink jet printing apparatus that prints by discharging ink from an ink jet head onto a print medium.

  In the ink jet printing apparatus, the ink in the nozzles may increase in viscosity or solidify, resulting in ink ejection failure. For this reason, in the ink jet printing apparatus, in the maintenance of the ink jet head, the thickened or solidified ink in the nozzle is removed.

  For example, an ink jet head is brought into contact with a cap that covers the nozzle, air is sucked from a suction hole provided in the cap, and negative pressure is introduced into the space in the cap, thereby sucking ink from the nozzle and increasing the viscosity. Alternatively, the solidified ink is removed from the nozzle.

  In such an ink jet printing apparatus, ink may adhere to the cap described above. If there is ink stuck to the edge of the cap, when the cap is brought into contact with the inkjet head in the above-described maintenance of the inkjet head, ink suction from the nozzle becomes insufficient due to poor sealing of the space in the cap. There is a fear. Further, if the ink is fixed to the suction hole, the suction force of air for introducing a negative pressure into the space in the cap is lowered, and there is a possibility that the suction of the ink from the nozzles becomes insufficient. Therefore, it is necessary to clean the cap in order to remove the ink adhered to the cap.

  As a technique for cleaning the cap of the inkjet head, for example, there is one disclosed in Patent Document 1. In the technique of Patent Document 1, the cap is cleaned by immersing the cap in a cleaning liquid stored in a cleaning liquid reservoir.

JP 2010-162814 A

  However, even if the cap is immersed in the cleaning liquid as in the technique of Patent Document 1, it is difficult to remove even the ink fixed to the suction hole of the cap, and it cannot be said that the cap can be sufficiently cleaned.

  The present invention has been made in view of the above, and an object of the present invention is to provide an inkjet printing apparatus that can reduce insufficient cleaning of the cap of the inkjet head.

  In order to achieve the above object, a first feature of an ink jet printing apparatus according to the present invention is an ink jet head having a nozzle for discharging ink, a cap that contacts the ink jet head and covers the nozzle, and a cap provided on the cap. A pump that is connected to the suction hole through the flow path and sucks the contents from the space in the cap, a cleaning liquid tank that stores the cleaning liquid, and the cleaning liquid in the cleaning liquid tank when cleaning the cap The pump is driven while the cap is immersed in the cleaning liquid, and the cleaning liquid is sucked into the flow path from the suction hole. And a control unit that controls to discharge from the suction hole.

  A second feature of the ink jet printing apparatus according to the present invention is that the two ink caps are provided for the one ink jet head, and the two caps have their opening ends in contact with the ejection surface of the ink jet head in opposite directions. And a drive unit that reverses the cap base so as to switch the cap whose opening end faces the ejection surface of the inkjet head.

  A third feature of the ink jet printing apparatus according to the present invention is that, in the capping state in which one of the two caps supported by the cap base is in contact with the ink jet head, the other cap is the cleaning liquid. It exists in the state immersed in the washing | cleaning liquid of a tank.

  According to the first feature of the ink jet printing apparatus according to the present invention, the ink can be cleaned by immersing the cap in the cleaning liquid, and the ink fixed to the suction hole can be removed by sucking and discharging the cleaning liquid from the suction hole. . Therefore, insufficient cleaning of the cap can be reduced.

  According to the second feature of the ink jet printing apparatus according to the present invention, since the two caps can be switched and used for capping, the ink jet head can be capped with the other cap during the cleaning of one cap.

  According to the third feature of the ink jet printing apparatus according to the present invention, in the capping state in which one cap is in contact with the ink jet head, the other cap is immersed in the cleaning liquid in the cleaning liquid tank. The state in which the cap is washed can be maintained.

1 is an overall perspective view of an inkjet printing apparatus according to a first embodiment. It is a front view which shows typically schematic structure of the inkjet printing apparatus shown in FIG. It is a schematic block diagram of the cap mechanism part of the inkjet printing apparatus shown in FIG. It is a perspective view of the principal part of a cap mechanism part. It is a control block diagram of the inkjet printing apparatus shown in FIG. It is a flowchart for demonstrating cap washing | cleaning operation | movement. It is a figure which shows the state which has a cap unit in a retracted position. It is a figure which shows the state where the cap was immersed in the cleaning liquid of the cleaning liquid tank. It is a schematic block diagram of the cap mechanism part in 2nd Embodiment. It is explanatory drawing of the capping state in 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals.

  The following embodiments exemplify devices for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, arrangement, etc. of each component. Is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
FIG. 1 is an overall perspective view of the inkjet printing apparatus according to the first embodiment of the present invention. FIG. 2 is a front view schematically showing a schematic configuration of the ink jet printing apparatus shown in FIG. FIG. 3 is a schematic configuration diagram of a cap mechanism portion of the ink jet printing apparatus shown in FIG. FIG. 4 is a perspective view of a main part of the cap mechanism portion. FIG. 5 is a control block diagram of the inkjet printing apparatus shown in FIG. In the following description, the vertical and horizontal directions indicated by the arrows in FIG.

  As shown in FIGS. 1, 2, and 5, the inkjet printing apparatus 1 according to the first embodiment includes a shuttle base unit 2, a flat bed unit 3, a shuttle unit 4, and a control unit 5.

  The shuttle base unit 2 supports the shuttle unit 4 and moves the shuttle unit 4 in the front-rear direction (sub-scanning direction). The shuttle base unit 2 includes a gantry 11 and a sub-scanning drive motor 12.

  The gantry 11 supports the shuttle unit 4. The gantry 11 is formed in a rectangular frame shape. Sub-scanning drive guides 13A and 13B extending in the front-rear direction are formed on the left and right frames of the gantry unit 11, respectively. The sub-scanning drive guides 13A and 13B guide the shuttle unit 4 to move in the front-rear direction.

  The sub-scanning drive motor 12 moves the shuttle unit 4 in the front-rear direction.

  The flat bed unit 3 holds a print medium 15 made of a base material such as a building material or a decorative panel. The flat bed unit 3 is disposed inside the gantry 11 of the shuttle base unit 2. The flat bed unit 3 has a medium placement surface 3a that is a horizontal surface on which the print medium 15 is placed. The flat bed unit 3 can adjust the height of the medium placement surface 3a by an elevating mechanism such as a hydraulic drive mechanism.

  The shuttle unit 4 prints an image on the print medium 15. As shown in FIGS. 1, 2, and 5, the shuttle unit 4 includes a housing 21, a main scanning drive guide 22, a main scanning drive motor 23, a head lifting guide 24, a head lifting motor 25, and a head. The unit 26, the cap mechanism part 27, and the wipe part 28 are provided.

  The housing 21 houses each part such as the head unit 26. The casing 21 is formed in a gate shape straddling the flat bed unit 3 in the left-right direction. The casing 21 is supported by the gantry 11 of the shuttle base unit 2 and is movable along the sub-scanning drive guides 13A and 13B.

  The main scanning drive guide 22 guides the head unit 26 to move in the left-right direction (main scanning direction). The main scanning drive guide 22 is formed in a long shape extending in the left-right direction.

  The main scanning drive motor 23 moves the head unit 26 in the left-right direction.

  The head lifting guide 24 guides the head unit 26 to move in the vertical direction. The head lifting guide 24 is formed in an elongated shape in the vertical direction. The head raising / lowering guide 24 is configured to be movable in the left-right direction along the main scanning drive guide 22 together with the head unit 26.

  The head lifting motor 25 moves the head unit 26 up and down.

  The head unit 26 prints an image by ejecting ink onto the print medium 15 while moving in the left-right direction along the main scanning drive guide 22. The head unit 26 includes four inkjet heads 31.

  The inkjet head 31 discharges aqueous ink to the print medium 15. The four inkjet heads 31 are arranged in parallel in the left-right direction. The four inkjet heads 31 eject inks of different colors (for example, cyan, black, magenta, and yellow). The inkjet head 31 has a plurality of nozzles (not shown) that are open on the ejection surface 31a that is the lower surface thereof, and ejects ink from the nozzles. The plurality of nozzles are arranged along the front-rear direction.

  The cap mechanism unit 27 covers the nozzles of the inkjet head 31 and performs capping with a space where the nozzles are opened as a closed space. The cap mechanism portion 27 is disposed inside the right end portion of the housing 21. As shown in FIGS. 2 to 5, the cap mechanism unit 27 includes four cap units 41, four pumps 42, four atmospheric release valves 43, a waste liquid tank 44, a cap lifting / lowering motor 45, and a cap rotation. A drive unit 46 and a cleaning liquid tank 47 are provided. Note that, in FIG. 3, the configuration corresponding to one inkjet head 31 is shown as a representative of the portions having the same configuration provided corresponding to each inkjet head 31.

  The cap unit 41 includes a cap 51, a cap base 52, a suction pipe (corresponding to a flow path in claims) 53, an air release pipe 54, and a worm 55.

  The cap 51 is a member that abuts on the ejection surface 31 a of the inkjet head 31 and performs capping. The cap 51 includes an ellipse-shaped ink receiving surface 56 that is a bottom portion, and a peripheral wall 57 that is erected on the periphery of the ink receiving surface 56. The ink receiving surface 56 is provided with a suction hole 56a for sucking air, ink and the like from the space in the cap 51, and an air release hole 56b for opening the space in the cap 51 to the atmosphere. The peripheral wall 57 is formed in a shape that surrounds all the nozzles when contacting the ejection surface 31 a of the inkjet head 31. The end on the opening side opposite to the ink receiving surface 56 side of the peripheral wall 57 forms the opening end 51 a of the cap 51.

  The cap base 52 supports the cap 51. The cap base 52 has a front surface 52a and a back surface 52b parallel to the ejection surface 31a of the inkjet head 31, and holds the cap 51 on the front surface 52a side. The cap base 52 holds the cap 51 so that the opening end 51a faces upward when the surface 52a faces upward. The cap base 52 is disposed below the inkjet head 31.

  The suction tube 53 constitutes a flow path for air, ink, or the like sucked from the space in the cap 51. One end of the suction pipe 53 is connected to the suction hole 56 a of the ink receiving surface 56, and the other end is connected to the waste liquid tank 44.

  The atmosphere release pipe 54 constitutes an air flow path for communicating the space in the cap 51 from the ink receiving surface 56 side to the atmosphere. One end of the atmosphere release pipe 54 is connected to the atmosphere release hole 56 b of the ink receiving surface 56. An atmosphere release valve 43 is connected to the other end (atmosphere release end) of the atmosphere release pipe 54.

  The worm 55 is rotated by the driving force of the cap rotation driving unit 46 to rotate the cap base 52 about the front-rear direction. The worm 55 is fixed to the front end of the cap base 52.

  The pump 42 is for sucking contents such as air and ink from the space in the cap 51. The pump 42 is configured to be capable of forward and reverse rotation. The pump 42 is installed in the middle of the suction pipe 53. That is, the pump 42 is connected to the suction hole 56 a of the cap 51 through the suction pipe 53.

  The atmosphere release valve 43 opens and closes the opening at the atmosphere release end of the atmosphere release pipe 54. When the atmosphere release valve 43 is open, the atmosphere release pipe 54 communicates with the atmosphere from the atmosphere release end, and when the atmosphere release valve 43 is closed, the atmosphere release pipe 54 is blocked from the atmosphere at the atmosphere release end.

  The waste liquid tank 44 stores ink or the like sent by the pump 42 via the suction pipe 53 as waste liquid.

  The cap lifting / lowering motor 45 moves the four cap units 41 and the cap rotation driving unit 46 up and down.

  The cap rotation drive unit 46 rotates the cap base 52 by rotating the worm 55. The cap rotation drive unit 46 includes four worm wheels 58 and a cap rotation motor 59.

  The worm wheel 58 meshes with the worm 55 and rotates around a rotation shaft (not shown) extending in the left-right direction, thereby rotating the worm 55. One worm wheel 58 is disposed in each of the four cap units 41. Four worm wheels 58 are fixed to a common rotating shaft.

  The cap rotation motor 59 rotates the rotation shaft of the worm wheel 58.

  The cleaning liquid tank 47 stores a cleaning liquid for cleaning the cap 51. The cleaning liquid tank 47 is disposed below the cap base 52.

  The cleaning liquid has a function of dissolving ink. As this cleaning liquid, for example, an aqueous solvent containing water and a surfactant can be used.

  Examples of the surfactant include fatty acid sodium, sodium alkylbenzene sulfonate, sodium alkyl sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfate ester, sodium alkyl ether sulfate ester, sodium α-sulfo fatty acid ester, sodium alkyl phosphate ester. Anionic surfactant such as alkyl cationic trimethylammonium, dialkyldimethylammonium, etc .; sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl Nonionic surfactants such as phenyl ethers; sodium alkylamino fatty acids, alkylbetaines, alkylamines Amphoteric surfactants such as oxide can be used. In addition, polymer surfactants, silicone surfactants, fluorine surfactants, acetylene glycol surfactants, and the like can also be used. Among these, it is preferable to use polyoxyethylene alkyl ether, the HLB value is 11 to 17, the number of carbon atoms of the alkyl group is 8 to 15, and the number of added moles of ethylene oxide is more preferably 6 to 25.

  The cleaning liquid preferably further contains a thickener. As the thickener, a water-soluble polymer thickener or a clay mineral thickener can be used. As the water-soluble polymer thickener, natural polymers, semi-synthetic polymers, and synthetic polymers can be used. Examples of natural polymers include plant-based natural polymers such as gum arabic, carrageenan, guar gum, locust bean gum, pectin, tragacanth gum, corn starch, konjac mannan, agar; Animal-based natural polymers such as gelatin, casein, and glue can be used. Examples of semi-synthetic polymers include cellulose-based semi-synthetic polymers such as ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, and hydroxypropyl methyl cellulose; starch-based compounds such as hydroxyethyl starch, sodium carboxymethyl starch, and cyclodextrin. Semi-synthetic polymers; Alginate-based semi-synthetic polymers such as sodium alginate and propylene glycol alginate; sodium hyaluronate can be used. As the synthetic polymer, for example, vinyl-based synthetic polymers such as polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, poly N-vinylacetamide, and polyacrylamide; polyethylene oxide, polyethyleneimine, and polyurethane can be used. As the clay mineral-based thickener, for example, smectite-based clay minerals such as montmorillonite, hectorite, and saponite can be used. Among these, it is preferable to use hydroxypropyl methylcellulose.

  Furthermore, in addition to the above components, the cleaning liquid can optionally contain a water-soluble organic solvent, a pH adjuster, an antioxidant, a preservative, and the like. The viscosity of the cleaning liquid is preferably 5 to 200 mPa · s at 23 ° C., and more preferably 10 to 100 mPa · s.

  The wipe unit 28 wipes the ejection surface 31 a of the inkjet head 31 during maintenance of the inkjet head 31. The wipe unit 28 is disposed inside the left end portion of the housing 21. The wipe unit 28 includes four wipers 61 and a wiper drive unit 62.

  The wiper 61 is a member that wipes the ejection surface 31 a of the inkjet head 31. The wiper 61 is made of a material such as elastically deformable rubber.

  The wiper drive unit 62 moves the four wipers 61 in the front-rear direction. The wiper drive unit 62 has a motor or the like (not shown).

  The control unit 5 controls the operation of the entire inkjet printing apparatus 1. The control unit 5 includes a CPU, a RAM, a ROM, a hard disk, and the like.

  When the cap 51 is cleaned, the control unit 5 rotates the cap base 52 by the cap rotation driving unit 46 so that the cap 51 is immersed in the cleaning liquid in the cleaning liquid tank 47. Then, the controller 5 drives the pump 42 in a state where the cap 51 is immersed in the cleaning liquid and sucks the cleaning liquid from the suction hole 56a into the suction pipe 53, and then drives the pump 42 in the reverse direction from the time of suction to Control is performed so that the cleaning liquid sucked into the nozzle 53 is discharged from the suction hole 56a.

  Next, the printing operation of the inkjet printing apparatus 1 will be described.

  In the inkjet printing apparatus 1, the shuttle unit 4 is disposed at the standby position in the standby state before the start of the printing operation. The standby position of the shuttle unit 4 is the position of the shuttle unit 4 indicated by a solid line in FIG.

  In the standby state of the inkjet printing apparatus 1, the head unit 26 is disposed at the home position above the cap mechanism unit 27. The cap unit 41 is at the capping position, and the inkjet head 31 is capped by the cap 51.

  When a print job is input, the control unit 5 controls the sub-scanning drive motor 12 to move the shuttle unit 4 from the standby position to the print processing start position. The printing process start position of the shuttle unit 4 is the position of the shuttle unit 4 indicated by a two-dot chain line in FIG. 1 and is at the front end of the gantry 11 of the shuttle base unit 2. Prior to the input of the print job, the print medium 15 is placed on the medium placement surface 3 a of the flat bed unit 3.

  Next, the control unit 5 controls the cap lifting / lowering motor 45 to move the cap unit 41 from the capping position to the lower retreat position. Thereby, the cap 51 is separated from the ejection surface 31a of the inkjet head 31, and the capping with respect to the inkjet head 31 is released.

  Next, the control unit 5 controls the main scanning drive motor 23 to move the head unit 26 in the main scanning direction, and controls the ink jet head 31 based on the print job to discharge ink from the nozzles, thereby causing one pass. Print minutes. Next, the control unit 5 controls the sub-scanning drive motor 12 to move the shuttle unit 4 backward to the printing position of the next pass. The controller 5 forms an image on the print medium 15 by alternately repeating the printing for one pass and the movement of the shuttle unit 4.

  When printing for one sheet is completed, the control unit 5 controls the main scanning drive motor 23 to place the head unit 26 at the home position. Then, the controller 5 controls the cap lifting / lowering motor 45 to move the cap unit 41 from the retracted position to the capping position, thereby capping the inkjet head 31 with the cap 51. Further, the control unit 5 controls the sub-scanning drive motor 12 to place the shuttle unit 4 at the standby position. Thereby, the printing operation is completed.

  Next, the cap cleaning operation in the inkjet printing apparatus 1 will be described.

  The cap cleaning operation is performed following release of the fill cap state when the inkjet printing apparatus 1 is powered on. Here, the fill cap state is a cap 51 surrounded by the ink receiving surface 56, the peripheral wall 57, and the discharge surface 31 a in a capping state in which the opening end 51 a of the cap 51 is in contact with the discharge surface 31 a of the inkjet head 31. The inside space is filled with ink. When the power of the inkjet printing apparatus 1 is turned off and the apparatus is not used for a long time, it is in the fill cap state to prevent the nozzles from drying.

  When the power of the inkjet printing apparatus 1 is turned on, the control unit 5 opens the atmosphere release valve 43 and drives the pump 42 to discharge the ink in the space in the cap 51 from the suction hole 56a. When the discharge of the ink in the space in the cap 51 is completed, the fill cap state is released.

  When the fill cap state is released, the controller 5 starts a cap cleaning operation. FIG. 6 is a flowchart for explaining the cap cleaning operation.

  In step S1 of FIG. 6, the control unit 5 controls the cap lifting / lowering motor 45 to move the cap unit 41 from the capping position to the retracted position. Here, as shown in FIG. 7, the retracted position of the cap unit 41 is a position immediately above the cleaning liquid tank 47. When the cap base 52 is rotated and turned upside down, the cap 51 is immersed in the cleaning liquid in the cleaning liquid tank 47. You are in a position where you can.

  Next, in step S <b> 2, the control unit 5 controls the cap rotation motor 59 to rotate the cap base 52 so that the cap 51 is immersed in the cleaning liquid in the cleaning liquid tank 47. Specifically, the control unit 5 controls the cap rotation motor 59 to rotate the cap base 52 by 180 °. As a result, as shown in FIG. 8, the cap base 52 is in a state where the surface 52 a faces downward, and the cap 51 is immersed in the cleaning liquid in the cleaning liquid tank 47. At this time, at least the opening end 51a of the cap 51 may be immersed in the cleaning liquid.

  Next, in step S3 of FIG. 6, the control unit 5 closes the atmosphere release valve 43 and then drives the pump 42 to suck the cleaning liquid from the suction hole 56a into the suction pipe 53.

  Next, in step S4, the control unit 5 drives the pump 42 in the reverse direction to the suction in step S3 to discharge the cleaning liquid sucked into the suction pipe 53 from the suction hole 56a. Thereafter, the control unit 5 opens the atmosphere release valve 43.

  Next, in step S <b> 5, the control unit 5 controls the cap rotation motor 59 to rotate the cap base 52 to lift the cap 51 from the cleaning liquid tank 47. Specifically, the control unit 5 controls the cap rotation motor 59 to rotate the cap base 52 by 180 °. As a result, the cap base 52 returns to the state where the surface 52 a faces upward, and the cap 51 is lifted from the cleaning liquid tank 47.

  Next, in step S6, the controller 5 controls the cap lifting motor 45 to move the cap unit 41 from the retracted position to the capping position. As a result, the cap cleaning operation is completed.

  By such a cap cleaning operation, the ink attached to the cap 51 in the fill cap state can be washed away by immersing the cap 51 in the cleaning liquid. Further, by sucking and discharging the cleaning liquid from the suction hole 56a by driving the pump 42, the ink attached to the suction hole 56a can be washed away.

  Thereby, it is possible to prevent the ink from adhering to the peripheral wall 57 and the suction hole 56a of the cap 51. Even when there is ink fixed to the peripheral wall 57 or the suction hole 56a of the cap 51, it can be melted and washed away with the cleaning liquid.

  Further, since the cleaning liquid in the cleaning liquid tank 47 is agitated by the suction and discharge of the cleaning liquid from the suction hole 56a, the cleaning liquid moves, so that the ink fixed to the cap 51 can be better removed.

  The cap cleaning operation described above is not limited to the timing immediately after the fill cap state is released when the ink jet printing apparatus 1 is turned on, but may be performed at other timings. For example, the cap cleaning operation may be performed during a printing operation or a wiping operation in a maintenance operation of the inkjet head 31 described later.

  Next, the maintenance operation of the inkjet head 31 in the inkjet printing apparatus 1 will be described.

  First, in a state where the cap 51 is capping the inkjet head 31, the controller 5 closes the atmosphere release valve 43, drives the pump 42, and sucks air from the space in the cap 51. A negative pressure is introduced into the space in 51. As a result, ink is sucked from the nozzles of the inkjet head 31, and the thickened or solidified ink is discharged from the nozzles. And it will be in the state which the ink adhered to the discharge surface 31a. Here, the ink sucked and dropped from the nozzle is received by the ink receiving surface 56 and flows from the suction hole 56 a to the waste liquid tank 44 through the suction pipe 53.

  Next, after the atmosphere release valve 43 is closed, the controller 5 controls the cap lifting motor 45 to move the cap unit 41 from the capping position to the retracted position. As a result, the capping of the inkjet head 31 by the cap 51 is released.

  Next, the control unit 5 controls the main scanning drive motor 23 to move the head unit 26 from the home position to above the wipe unit 28. Thereafter, the control unit 5 controls the head lifting motor 25 to lower the head unit 26 to the wipe position. The wipe position of the head unit 26 is the position of the head unit 26 for wiping the ejection surface 31 a of the inkjet head 31 with the wiper 61.

  Next, the control unit 5 controls the wiper driving unit 62 to move the wiper 61. Accordingly, the wiper 61 wipes the ejection surface 31a of the inkjet head 31.

  When the wiping of the ejection surface 31a of the inkjet head 31 is completed, the control unit 5 controls the head lifting motor 25 to raise the head unit 26 from the wipe position, and then controls the main scanning drive motor 23 to control the head unit 26. Return to the home position.

  Next, the controller 5 controls the cap lifting motor 45 to move the cap unit 41 from the retracted position to the capping position. Thereby, the cap 51 caps the inkjet head 31, and the maintenance operation of the inkjet head 31 is completed.

  Here, if the ink adheres to the edge (opening end 51a) of the cap 51, when the negative pressure is introduced into the space in the cap 51, the opening end 51a of the cap 51 that is in contact with the discharge surface 31a and the discharge are discharged. A gap may be formed between the surface 31a and the space in the cap 51 may be poorly sealed. As a result, ink suction from the nozzles may be insufficient.

  Further, if the ink is fixed in the suction hole 56a of the cap 51, the suction force when the pump 42 sucks air through the suction hole 56a to introduce a negative pressure into the space in the cap 51 is reduced. Sometimes. As a result, ink suction from the nozzles may be insufficient.

  If the ink suction from the nozzles is insufficient, the thickened or solidified ink remains in the nozzles, and as a result, the print image quality may be deteriorated. On the other hand, in the ink jet printing apparatus 1, the fixing of the ink to the edge of the cap 51 and the suction hole 56a is prevented by the cap cleaning operation described above. Even if the ink is fixed to the edge of the cap 51 or the suction hole 56a, the fixed ink is removed by the cap cleaning operation described above. Thereby, ink suction failure from the nozzles in the maintenance operation of the inkjet head 31 is suppressed.

  As described above, in the inkjet printing apparatus 1, when cleaning the cap 51, the control unit 5 rotates the cap base 52 by the cap rotation driving unit 46 so that the cap 51 is immersed in the cleaning liquid in the cleaning liquid tank 47. Then, the controller 5 drives the pump 42 in a state where the cap 51 is immersed in the cleaning liquid and sucks the cleaning liquid from the suction hole 56a into the suction pipe 53, and then drives the pump 42 in the reverse direction from the time of suction to Control is performed so that the cleaning liquid sucked into the nozzle 53 is discharged from the suction hole 56a. Accordingly, the cap 51 can be cleaned by immersing it in the cleaning liquid, and the ink fixed to the suction hole 56a can be removed by sucking and discharging the cleaning liquid from the suction hole 56a. Therefore, according to the ink jet printing apparatus 1, insufficient cleaning of the cap 51 can be reduced.

(Second Embodiment)
Next, a second embodiment in which the cap mechanism portion of the above-described embodiment is changed will be described. FIG. 9 is a schematic configuration diagram of a cap mechanism section in the second embodiment.

  As shown in FIG. 9, the cap mechanism portion 27A in the second embodiment has a configuration in which the cap unit 41 of the cap mechanism portion 27 of the first embodiment described above is replaced with a cap unit 41A.

  The cap unit 41A has a configuration in which a cap 51A having the same configuration as the cap 51 is added to the cap unit 41 of the first embodiment. Further, in the cap unit 41A, the suction pipe 53 and the atmosphere release pipe 54 of the cap unit 41 of the first embodiment are replaced with the suction pipe 53A and the atmosphere release pipe 54A, respectively, and valves 71A, 71B, 72A, 72B are added. Yes.

  The cap 51A is disposed on the back surface 52b side of the cap base 52. The cap 51A is installed so that the open end 51a is downward when the back surface 52b of the cap base 52 is facing downward. That is, the cap base 52 holds the caps 51 and 51A with the open ends 51a facing in opposite directions.

  The suction tube 53A is obtained by branching the suction tube 53 of the first embodiment into two from the pump 42 on the caps 51 and 51A side. One end of the two branched pipes of the suction pipe 53A is connected to the suction hole 56a of the cap 51, and the other end is connected to the suction hole 56a of the cap 51A.

  The atmosphere release pipe 54A is a branch of the atmosphere release pipe 54 of the first embodiment. One end of the two branched air release pipes 54A is connected to the air release hole 56b of the cap 51, and the other end is connected to the air release hole 56b of the cap 51A.

  The valve 71A is disposed between the branch point of the suction pipe 53A and the suction hole 56a of the cap 51, and opens and closes the flow path in the suction pipe 53A in that section. The valve 71B is disposed between the branch point of the suction pipe 53A and the suction hole 56a of the cap 51A, and opens and closes the flow path in the suction pipe 53A in that section.

  The valve 72A is disposed between the branch point of the atmosphere release pipe 54A and the atmosphere release hole 56b of the cap 51, and opens and closes the flow path in the atmosphere release pipe 54A in that section. The valve 72B is disposed between the branch point of the atmosphere release pipe 54A and the atmosphere release hole 56b of the cap 51A, and opens and closes the flow path in the atmosphere release pipe 54A in that section.

  In the second embodiment, one of the caps 51 and 51A selectively capping the inkjet head 31. By rotating the cap base 52 by the cap rotation driving unit 46 and reversing the front and back, the cap whose opening end 51a faces the ejection surface 31a of the inkjet head 31 is switched. In addition, the cap rotation drive part 46 in 2nd Embodiment is corresponded to the drive part of a claim.

  In the second embodiment, when either one of the caps 51 and 51A is in the capping state, the other cap is immersed in the cleaning liquid in the cleaning liquid tank 47. The height position is adjusted. For example, as shown in FIG. 10, when the cap 51 is in the capping state, the cap 51 </ b> A is immersed in the cleaning liquid in the cleaning liquid tank 47.

  The cap cleaning operation in the second embodiment is performed in the same manner as in the first embodiment. That is, the controller 5 immerses the cap 51 or the cap 51A in the cleaning liquid tank 47, drives the pump 42 in that state, sucks the cleaning liquid from the suction hole 56a into the suction pipe 53A, and then reverses the pump 42 when sucking. The cleaning liquid sucked into the suction pipe 53A is driven and discharged from the suction hole 56a. However, in the second embodiment, during the cap cleaning operation, the valve 71A, 71B, 72A, 72B corresponding to the cap opposite to the cap to be cleaned is closed. For example, when cleaning the cap 51A on the back surface 52b side, the valves 71A and 72A are closed. This is because the space in the cap 51A is sealed.

  As described above, in the second embodiment, the cap base 52 holds the two caps 51 and 51A. Then, by turning the cap base 52 upside down by the cap rotation driving unit 46, the two caps 51 and 51A can be switched and used for capping. For this reason, the inkjet head 31 can be capped with the other cap during the cleaning of the one cap.

  In the second embodiment, when any one of the caps 51 and 51A is in the capping state, the other cap is immersed in the cleaning liquid in the cleaning liquid tank 47. Thereby, the state by which one cap is wash | cleaned can be maintained.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Inkjet printing apparatus 2 Shuttle base unit 3 Flat bed unit 4 Shuttle unit 5 Control part 26 Head unit 27, 27A Cap mechanism part 28 Wipe part 41, 41A Cap unit 42 Pump 43 Atmospheric release valve 45 Cap raising / lowering motor 46 Cap rotation drive part 47 Cleaning liquid tank 51, 51A Cap 51a Open end 52 Cap base 53, 53A Suction pipe 54, 54A Atmospheric release pipe 56 Ink receiving surface 57 Peripheral wall 56a Suction hole 56b Atmospheric release hole 59 Cap rotation motor

Claims (3)

An inkjet head having a nozzle for ejecting ink;
A cap that contacts the inkjet head and covers the nozzle;
A pump connected to a suction hole provided in the cap via a flow path, and sucking the contents from the space in the cap;
A cleaning liquid tank for storing the cleaning liquid;
At the time of cleaning the cap, the cap is immersed in the cleaning liquid in the cleaning liquid tank, and the pump is driven in a state where the cap is immersed in the cleaning liquid to suck the cleaning liquid from the suction hole into the flow path, and then the pump is sucked. An inkjet printing apparatus comprising: a controller that is driven reversely to the time and controls to discharge the cleaning liquid sucked into the flow path from the suction hole. Two caps are provided for one inkjet head,
A cap base that holds the two caps in such a manner that opening ends that contact the ejection surface of the inkjet head face each other in opposite directions;
The inkjet printing apparatus according to claim 1, further comprising: a drive unit that reverses the cap base so as to switch the cap whose opening end faces the ejection surface of the inkjet head.   In the capping state where one of the two caps supported by the cap base is in contact with the inkjet head, the other cap is immersed in the cleaning liquid in the cleaning liquid tank. The inkjet printing apparatus according to claim 2.