Liquid ejection device and inkjet printing device

Abstract

To provide a liquid ejecting device that can prevent liquid ejected from a cap part from becoming solidified in a flow passage extending to a waste liquid tank and then clogging the flow passage, and an inkjet printing device.SOLUTION: The liquid ejecting device comprises: a first cap-side flow passage 47 through which ink discharged into first-fourth cap parts 41-44 sealing a discharge port of an inkjet head is ejected; and a first wiper-side flow passage 38 through which cleaning liquid is ejected from a wiping unit 30 that wipes the discharge port of the inkjet head, which further has a first merging position S1 at which the first cap-side flow passage 47 and the first wiper-side flow passage 38 merge with each other, where an identical flow passage 53 is formed from the first merging position S1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a liquid discharging device that discharges a predetermined liquid to the outside via a flow path, and to an inkjet printing apparatus equipped with the liquid discharging device. [Background technology]

[0002] 2. Description of the Related Art Inkjet printing devices have been proposed that perform printing by ejecting ink from an inkjet head onto a print medium such as paper or film.

[0003] In an inkjet printing device, ink may adhere to the ink ejection openings of the nozzles, or dirt such as paper dust generated from the paper may adhere to the ink ejection openings of the nozzles. If ink adheres to the ink ejection openings of the nozzles or paper dust accumulates, ejection defects such as disturbance of the ink ejection direction from the nozzles or failure to eject ink may occur.

[0004] In order to reduce such ejection defects, a series of operations is known in which ink is forcibly ejected from the nozzles of the inkjet head, that is, a so-called purge is performed, and then the ink ejection openings of the nozzles are wiped with a wiper.

[0005] To perform this series of operations, for example, Patent Document 1 proposes an inkjet printing device that includes a wiping unit having a wiper and a capping unit having a cap portion that receives ink ejected from the inkjet head during purging.

[0006] The cap portion seals the ink ejection surface of the ink jet head to prevent the ink from drying out on the ink ejection surface, and also serves the role of receiving the ink ejected from the ink jet head during purging, as described above.

[0007] In the wiping unit, after cleaning the ink ejection surface with a wiper, the wiper is immersed in a cleaning liquid tank filled with cleaning liquid to clean the wiper itself. The cleaning liquid in the cleaning liquid tank is then discarded at regular intervals.

[0008] On the other hand, in the capping unit, the ink received by the cap portion is also sucked by a pump or the like, and is discarded into a waste liquid tank via a flow path such as a tube. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2018-149461 A Summary of the Invention [Problem to be solved by the invention]

[0010] However, since the amount of ink ejected from the inkjet head during purging is extremely small, the amount of waste liquid discharged into the flow path such as the tube is also extremely small. Furthermore, since the distance from the capping unit to the waste liquid tank is long, the ink discarded by purging may dry out in the flow path such as the tube, increase in viscosity, and solidify, causing the problem of tube clogging.

[0011] An object of the present invention is to provide a liquid discharging device and an inkjet printing device that can prevent liquid discharged from a cap portion from solidifying and clogging a flow path to a waste liquid tank. [Means for solving the problem]

[0012] The liquid discharging device of the present invention comprises a cap-side flow path through which discharged liquid is discharged into a cap portion that seals the discharge port of a discharge portion having an outlet through which liquid is discharged, and a wiper-side flow path through which cleaning liquid is discharged from a wiping portion that wipes the discharge port of the discharge portion, and has a junction where the cap-side flow path and the wiper-side flow path join, and a common flow path is formed from the junction. Effect of the Invention

[0013] According to the liquid discharging device of the present invention, there is a junction where the cap side flow path and the wiper side flow path join, and the same flow path is formed from that junction. Therefore, the cleaning liquid discharged from the wiping section can be made to flow into the same flow path via the wiper side flow path, thereby preventing the liquid discharged from the cap section from solidifying and clogging the flow path to the waste liquid tank. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an inkjet printing device using an embodiment of a liquid ejection device of the present invention [Diagram 2] A view of the inkjet printing device shown in Figure 1 from the direction of arrow A. [Diagram 3] FIG. 1 is a diagram showing a schematic configuration of an example of a head unit; [Figure 4] FIG. 2 is a diagram showing a schematic configuration of a capping unit and a wiping unit; [Diagram 5] FIG. 1 is a diagram for explaining a wiping operation in a wiping unit; [Figure 6] FIG. 2 is a diagram showing a schematic configuration of an example of a cap portion; [Figure 7] A block diagram showing the configuration of a control system of an inkjet printing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An inkjet printing apparatus using one embodiment of a liquid discharging device of the present invention will be described in detail below with reference to the drawings. The inkjet printing apparatus of this embodiment is characterized by the configuration of the liquid discharging device, but first, the configuration of the entire inkjet printing apparatus will be described. FIG. 1 is a schematic diagram of an inkjet printing apparatus 1 of this embodiment. FIG. 2 is a view of the inkjet printing apparatus 1 shown in FIG. 1 as seen from the direction of arrow A. In the following description of the embodiment, the up, down, left, right, front, back, and rear indicated by arrows in FIG. 1 are defined as the up, down, left, right, front, and rear directions of the inkjet printing apparatus 1.

[0016] As shown in FIG. 1, the inkjet printing apparatus 1 of this embodiment includes a base 2, a foot stand 3, a platen 4, a rail section 5, a head unit 10, and a maintenance unit 20.

[0017] The bases 2 are columnar members extending in the front-rear direction and arranged in parallel with a gap in the left-right direction. Two wheels 2a are provided on the bottom surface of each of the two bases 2.

[0018] A foot stand 3 is provided upright on each base 2. A platen 4 is supported on the upper surfaces of the two foot stands 3 facing each other.

[0019] An arc-shaped front paper guide 4a and a rear paper guide 4b extend from the front and rear of the platen 4. Also, as shown in Fig. 2, a vacuum chamber 4c in which a fan 4d is installed is provided below the platen 4. Note that the vacuum chamber 4c is not shown in Fig. 1.

[0020] When the fan 4d in the vacuum chamber 4c rotates, a negative pressure is created inside the vacuum chamber 4c, and a suction force is generated in the suction holes (not shown) formed in the platen 4. The printing paper P is attracted to the platen 4 by the suction force generated in the suction holes of the platen 4.

[0021] 2, a drive roller 6 and a pressure roller 7 are provided behind the platen 4 so as to face each other. Note that the drive roller 6 and the pressure roller 7 are omitted from FIG.

[0022] The drive roller 6 is an elongated roller extending in the extension direction of the platen 4, and is rotated by a transport drive motor 61 (see FIG. 7) which will be described later.

[0023] The pressure roller 7, like the drive roller 6, is an elongated roller extending in the extension direction of the platen 4, and is supported by a lifting mechanism (not shown) so as to be movable up and down.

[0024] Then, the printing paper P on the rear paper guide 4b is clamped between the drive roller 6 and the pressure roller 7, and as the drive roller 6 rotates with the printing paper P pressed by the pressure roller 7, the printing paper P is sent forward.

[0025] A take-up core holder 8 is provided on the front side of the base 2 of the inkjet printing device 1, which detachably holds a core 8a that takes up the printing paper P. The take-up core holder 8 is connected to a take-up drive motor 81 (see FIG. 7) via a torque limiter (not shown), and is configured so that the take-up core holder 8 is rotated by the take-up drive motor 81.

[0026] Further, a supply-side core holding section 9 is provided on the rear side of the base 2 of the inkjet printing device 1, which detachably holds a core 9a of rolled paper on which printing paper P is wound in a roll shape. The supply-side core holding section 9 is linked to a supply drive motor 91 (see FIG. 7) via a torque limiter (not shown), and is configured so that the supply-side core holding section 9 is rotated by the supply drive motor 91.

[0027] As shown in Figure 2, the roll paper (printing paper P) held by the supply side core holding section 9 is pulled out and passed through the rear paper guide 4b, between the drive roller 6 and the pressure roller 7, over the platen 4, and the front paper guide 4a, before being wound onto the core 8a held by the winding side core holding section 8.

[0028] A rail section 5 is installed via a support member (not shown) on the upper part of the two legs 3. The rail section 5 includes a rail (not shown) extending in the left-right direction and a main scanning drive motor 54 (see FIG. 7) that moves the head unit 10 back and forth in the left-right direction on the rail.

[0029] A maintenance unit 20 is provided at one end of the rail portion 5. A wiping unit 30 and a capping unit 40, which will be described later, are provided within the maintenance unit 20. The head unit 10 is disposed within the maintenance unit 20, whereby wiping by the wiping unit 30 and capping by the capping unit 40 are performed. In this embodiment, the maintenance unit 20 includes a configuration equivalent to the liquid discharging device of the present invention.

[0030] Extending from the maintenance unit 20 are a common flow path 52 (described later) through which cleaning liquid containing a pretreatment liquid is discharged, and a common flow path 53 (described later) through which cleaning liquid containing an ink is discharged. A waste liquid tank 50 is provided at the end of the common flow path 52, and a waste liquid tank 51 is provided at the end of the common flow path 53.

[0031] The waste liquid tank 50 and the waste liquid tank 51 are installed near the base 2 below the maintenance unit 20.

[0032] Fig. 3 is a diagram showing a schematic configuration of the head unit 10. As shown in Fig. 3, the head unit 10 of this embodiment is provided with five heads, namely a first head 11 to a fifth head 15. The second head 12, the third head 13, and the fourth head 14 are inkjet heads that eject ink of different colors, for example, C (cyan), M (magenta), and Y (yellow) inks.

[0033] The fifth head 15 has a configuration similar to the second head 12 to the fourth head 14, but ejects a pretreatment liquid instead of ink. The pretreatment liquid is a liquid that is applied for pretreatment before ink is ejected onto the printing paper P to perform printing processing. As the pretreatment liquid, for example, a liquid for improving the color development and uniform application of the ink is used, but a pretreatment liquid that is already known can be used. In this embodiment, the fifth head 15 corresponds to the treatment liquid head of the present invention.

[0034] The first head 11 is an inkjet head that ejects ink in the same manner as the second to fourth heads 12 to 14. For example, when printing a pattern on a black base, the first head 11 ejects white ink onto the black base so that the black color of the base does not show through.

[0035] As shown in FIG. 3, the first to fifth heads 11 to 15 are arranged side by side in the movement direction (left and right direction) of the head unit 10, but the first head 11 and the second to fourth heads 12 to 14 are staggered, and the fifth head 15 and the second to fourth heads 12 to 14 are also staggered.

[0036] That is, the second to fourth heads 12 to 14 and the first and fifth heads 11, 15 are arranged at different positions in the direction (front-rear direction) orthogonal to the moving direction of the head unit 10. And the first head 11 and the fifth head 15 are arranged at the same position in the direction (front-rear direction) orthogonal to the moving direction of the head unit 10. Also, the second to fourth heads 12 to 14 are also arranged at the same position in the direction (front-rear direction) orthogonal to the moving direction of the head unit 10.

[0037] Next, the maintenance unit 20 of the present embodiment will be described. FIG. 4 is a diagram showing a schematic configuration of the maintenance unit 20 of the present embodiment.

[0038] As shown in FIG. 4, a wiping unit 30 and a capping unit 40 are installed in the maintenance unit 20. Note that the wiping unit 30 in the present embodiment corresponds to the wiping portion of the present invention, and the capping unit 40 corresponds to the capping portion of the present invention.

[0039] The wiping unit 30 and the capping unit 40 are arranged side by side in the moving direction (left-right direction) of the head unit 10. In the present embodiment, they are arranged in the order of the wiping unit 30 and the capping unit 40 from the main body side of the inkjet printing apparatus 1, but they may be arranged in the reverse order.

[0040] The wiping unit 30 includes a cleaning liquid tank 30a, first to fifth wipers 31a to 31e, first and second belt conveyance rollers 33, 34, and first and second conveyance belts 32, 35.

[0041] The first to fourth wipers 31a to 31d are wipers corresponding to the first to fourth heads 11 to 14, and wipe the ejection surfaces of the first to fourth heads 11 to 14. The ejection surface is the surface on which the ink ejection ports of the nozzles of the inkjet head are arranged.

[0042] The fifth wiper 31e is a wiper that corresponds to the fifth head 15 and wipes the ejection surface of the fifth head 15.

[0043] The first to fifth wipers 31a to 31e are arranged at intervals equal to the intervals between the first to fifth heads 11 to 15 in the movement direction of the head unit .

[0044] The first to fourth wipers 31a to 31d are erected at the same positions in the front-rear direction on the first conveyor belt 32. The fifth wiper 31e is erected on the second conveyor belt .

[0045] The first to fifth wipers 31a to 31e are made of flexible rubber or the like.

[0046] The cleaning liquid tank 30a stores a cleaning liquid. The cleaning liquid tank 30a has two recesses, a first cleaning liquid tank 30c and a second cleaning liquid tank 30d, and a partition wall 30b is provided between the first cleaning liquid tank 30c and the second cleaning liquid tank 30d. In other words, the first cleaning liquid tank 30c and the second cleaning liquid tank 30d are formed as completely independent cleaning liquid tanks.

[0047] The cleaning liquid has a function of dissolving the ink, and may be, for example, an aqueous solvent containing water and a surfactant.

[0048] Examples of the surfactant include anionic surfactants such as sodium fatty acid, sodium alkylbenzenesulfonate, sodium alkylsulfonate, sodium α-olefinsulfonate, sodium alkyl sulfate, sodium alkyl ether sulfate, sodium α-sulfofatty acid ester, and sodium alkyl phosphate; cationic surfactants such as alkyltrimethylammonium and dialkyldimethylammonium; nonionic surfactants such as sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenyl ether; and amphoteric surfactants such as sodium alkylamino fatty acid, alkyl betaine, and alkylamine oxide. Polymer surfactants, silicone surfactants, fluorine surfactants, and acetylene glycol surfactants can also be used. Among these, it is preferable to use polyoxyethylene alkyl ether, and it is more preferable that the HLB value is 11 to 17, the number of carbon atoms in the alkyl group is 8 to 15, and the number of moles of ethylene oxide added is 6 to 25.

[0049] The cleaning solution 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, a natural polymer, a semi-synthetic polymer, or a synthetic polymer can be used. As the natural polymer, for example, a plant-based natural polymer such as gum arabic, carrageenan, guar gum, locust bean gum, pectin, tragacanth gum, corn starch, konjac mannan, agar, etc.; a microbial natural polymer such as pullulan, xanthan gum, dextrin, etc.; an animal-based natural polymer such as gelatin, casein, or glue can be used. As the semi-synthetic polymer, for example, a cellulose-based semi-synthetic polymer such as ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, or hydroxypropyl methyl cellulose can be used; a starch-based semi-synthetic polymer such as hydroxyethyl starch, sodium carboxymethyl starch, or cyclodextrin; an alginic acid-based semi-synthetic polymer such as sodium alginate or propylene glycol alginate; or sodium hyaluronate can be used. Examples of synthetic polymers that can be used include vinyl synthetic polymers such as polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, poly N-vinylacetamide, and polyacrylamide; polyethylene oxide, polyethyleneimine, and polyurethane. Examples of clay mineral thickeners that can be used include smectite clay minerals such as montmorillonite, hectorite, and saponite. Among these, it is preferable to use hydroxypropyl methylcellulose.

[0050] Furthermore, in addition to the above components, the cleaning solution may optionally contain water-soluble organic solvents, pH adjusters, antioxidants, preservatives, etc. The viscosity of the cleaning solution at 23°C is preferably 5 to 200 mPa s, and more preferably 10 to 100 mPa s.

[0051] The first cleaning liquid tank 30c contains a first conveyor belt 32 having first to fourth wipers 31a to 31d arranged thereon, and the second cleaning liquid tank 30d contains a second conveyor belt 35 having a fifth wiper 31e arranged thereon.

[0052] Further, first and second belt conveying rollers 33, 34 are provided in the first cleaning liquid tank 30c and the second cleaning liquid tank 30d. The first and second belt conveying rollers 33, 34 extend in the left-right direction across the first cleaning liquid tank 30c and the second cleaning liquid tank 30d.

[0053] The first and second belt conveying rollers 33, 34 are arranged in parallel with a gap of at least the length of the head unit 10 in the front-to-rear direction, and the first conveying belt 32 and the second conveying belt 35 are stretched between the first belt conveying roller 33 and the second belt conveying roller 34.

[0054] 5, the first and second conveyor belts 32, 35 are moved by the rotation of the first belt conveyor roller 33 and the second belt conveyor roller 34 by a belt drive motor 39 (see FIG. 7). As a result, the first to fifth wipers 31a to 31e move in the front-to-rear direction (the direction in which the nozzles of the first to fifth heads 11 to 15 are arranged) to wipe the ejection surfaces of the first to fifth heads 11 to 15.

[0055] 5 shows only the first wiper 31a wiping the first head 11 as a representative example, but the second to fifth wipers 31b to 31e wiping the second to fifth heads 11 to 15 are similarly shown. Also, L shown in Fig. 5 is a cleaning liquid, and the cleaning liquid L is stored up to the lower half position of the first and second conveyor belts 32, 35 as shown in Fig. 5.

[0056] Returning to FIG. 4, a first wiper-side flow path 38 is connected to the first cleaning liquid tank 30c, and a second wiper-side flow path 37 is connected to the second cleaning liquid tank 30d.

[0057] The first wiper-side flow path 38 is provided with a first pump P1, and the second wiper-side flow path 37 is provided with a second pump P2.

[0058] Then, the first pump P1 provided in the first wiper-side flow path 38 is operated to discharge the cleaning liquid stored in the first cleaning liquid tank 30c to the first wiper-side flow path 38. The second pump P2 provided in the second wiper-side flow path 37 is operated to discharge the cleaning liquid stored in the second cleaning liquid tank 30d to the second wiper-side flow path 37. In this embodiment, the first and second pumps P1 and P2 correspond to the discharge unit of the present invention. In addition, the first cleaning liquid tank 30c and the second cleaning liquid tank 30d are each provided with a supply unit (not shown) that supplies the cleaning liquid, and when the cleaning liquid is discharged from the first cleaning liquid tank 30c and the second cleaning liquid tank 30d as described above, new cleaning liquid is supplied by the supply unit. The timing of discharging the cleaning liquid from the first cleaning liquid tank 30c and the second cleaning liquid tank 30d will be described in detail later.

[0059] Next, a description will be given of the capping unit 40. The capping unit 40 seals the ejection surfaces (ejection openings) of the first to fifth heads 11 to 15 to prevent the ejection surfaces (ejection openings) of the first to fifth heads 11 to 15 from drying out while the inkjet printing device 1 is on standby and not performing a printing process.

[0060] The capping unit 40 specifically includes first to fifth cap parts 41-45.

[0061] The first to fifth cap portions 41 to 45 are cap portions corresponding to the first to fifth heads 11 to 15, and are provided on the plate material 40a at positions corresponding to the first to fifth heads 11 to 15.

[0062] 6 is a diagram showing the configuration of the first cap part 41. The first cap part 41 includes a base 41a and a capping member 41b formed on the base 41a. The capping member 41b includes a bottom part 41c and a peripheral wall 41d standing on the peripheral edge of the bottom part 41c. Two discharge holes 41e are formed in the bottom part 41c.

[0063] The length of the capping member 41b in the front-rear direction is equal to the length of the first head 11 in the front-rear direction. A peripheral wall 41d of the capping member 41b is formed from a resin such as rubber, and abuts against and adheres closely to the first head 11 to seal the ejection surface of the first head 11.

[0064] Furthermore, when the first head 11 is purged, the liquid discharged from the first head 11 is received by the capping member 41b and discharged from the discharge hole 41e formed in the bottom portion 41c.

[0065] The second to fifth cap parts 42 to 45 are similar in configuration and function to the first cap part 41.

[0066] Further, a lower surface of the plate material 40a (the surface opposite to the surface on which the first to fifth cap portions 41 to 45 are provided) is provided with a discharge path portion 46. The discharge path portion 46 is provided in each of the first to fifth cap portions 41 to 45.

[0067] A first cap side flow path 47 is connected to the discharge path section 46 corresponding to the first cap portion 41, and discharge flow paths (not shown) connected to the first cap side flow path 47 are connected to the discharge path sections 46 (not shown) corresponding to the second to fourth cap portions 42 to 44. The three discharge flow paths (not shown) are connected to the first cap side flow path 47 upstream of the third pump P3. That is, the first cap side flow path 47 and the three discharge flow paths (not shown) are connected in a four-way branch upstream of the third pump P3.

[0068] Therefore, the ink discharged to the discharge flow path (not shown) connected to the discharge path portion 46 (not shown) corresponding to the second to fourth cap portions 42 to 44 merges with the ink discharged to the first cap side flow path 47 connected to the discharge path portion 46 corresponding to the first cap portion 41 and flows into the third pump P3.

[0069] On the other hand, a second cap side flow path 48 is connected to the discharge path portion 46 corresponding to the fifth cap portion 45. The first cap side path 47 and the three discharge paths connected thereto do not communicate with the second cap side flow path 47, and are independent of each other. Then, the pre-treatment liquid is discharged from the discharge path portion 46 corresponding to the fifth cap portion 45 to the second cap side flow path 48.

[0070] Then, by operating the third pump P3 provided in the first cap side flow path 47, the ink received in the first to fourth cap portions 41 to 44 by purging is discharged to the first cap side flow path 47 via the discharge hole 41e and the discharge path portion 46.

[0071] The first cap-side flow path 47 is connected to the first wiper-side flow path 38 in the vicinity of the downstream side of the third pump P3, thereby forming a first junction S1. A common flow path 53 is formed from the first junction S1. As a result, the cleaning liquid discharged from the first cleaning liquid tank 30c flows out to the common flow path 53 via the first wiper-side flow path 38 and the first junction S1.

[0072] This allows the cleaning liquid to flow from the first junction S1 to the common flow path 53, so that the ink discharged into the first cap-side flow path 47 and adhering to the common flow path 53 can be flushed out by the cleaning liquid. This makes it possible to prevent the ink discharged by purging from solidifying and clogging the common flow path 53.

[0073] The cleaning liquid containing the ink that has flowed into the common flow path 53 is discharged into a waste liquid tank 51 connected to the tip of the common flow path 53 .

[0074] Further, a fourth pump P4 is provided in the second cap side flow path 48. When the fourth pump P4 is operated, the pre-treatment liquid received in the fifth cap portion 45 by the purging is discharged to the second cap side flow path 48 via the discharge hole 41e and the discharge path portion 46.

[0075] The second cap-side flow path 48 is connected to the second wiper-side flow path 37 in the vicinity of the downstream side of the fourth pump P4, thereby forming a second junction S2. A common flow path 52 is formed from the second junction S2. As a result, the cleaning liquid discharged from the second cleaning liquid tank 30d flows out to the common flow path 52 via the second wiper-side flow path 37 and the second junction S2.

[0076] This allows the cleaning liquid to flow from the second junction S2 to the common flow path 52, so that the pre-treatment liquid discharged to the second cap-side flow path 48 and adhering to the common flow path 52 can be flushed out by the cleaning liquid. This prevents the pre-treatment liquid discharged by purging from solidifying and clogging the common flow path 52.

[0077] The cleaning liquid containing the pretreatment liquid flowing into the same flow path 52 is discharged into a waste liquid tank 50 connected to the tip of the same flow path 52 .

[0078] In this embodiment, the same flow path 53 is set to be longer than the length of the first wiper side flow path 38 (the length from the connection point of the first wiper side flow path 38 to the first cleaning liquid tank 30c to the first junction point S1) and the length of the first cap side flow path 47 (the length from the connection point of the first cap side flow path 47 to the discharge path portion 46 corresponding to the first cap portion 41 to the first junction point S1).

[0079] In addition, the same flow path 52 is set to be longer than the length of the second wiper side flow path 37 (the length from the connection point of the second wiper side flow path 37 to the second cleaning liquid tank 30d to the second junction point S2) and the length of the second cap side flow path 48 (the length from the connection point of the second cap side flow path 48 to the discharge path portion 46 corresponding to the fifth cap portion 45 to the second junction point S2).

[0080] By setting the lengths of the common flow paths 52, 53 as described above, clogging due to ink or pretreatment liquid can be more effectively prevented.

[0081] In addition, in this embodiment, as described above, the first cap-side flow path 47 from which ink is discharged and the first wiper-side flow path 38 from which cleaning liquid containing ink is discharged are merged at a first merging point S1 to form the same flow path 53, and the second cap-side flow path 48 from which pre-treatment liquid is discharged and the second wiper-side flow path 37 from which cleaning liquid containing pre-treatment liquid is discharged are merged at a second merging point S2 to form the same flow path 52.

[0082] That is, the ink and the pretreatment liquid are prevented from mixing in the flow path, which can prevent the ink from solidifying due to mixing of the ink and the pretreatment liquid, thereby preventing clogging of the flow path.

[0083] Fig. 7 is a block diagram showing the configuration of a control system of the inkjet printing apparatus 1 of this embodiment. The inkjet printing apparatus 1 operates each of the controlled units shown in Fig. 7 in response to control signals from the print control device 16. In this embodiment, the print control device 16 corresponds to the control unit of the present invention.

[0084] The print control device 16 and the inkjet printing device 1 are connected by a communication line such as a LAN (Local Area Network) or an Internet line, and are configured to be able to communicate with each other. The communication line may be wired or wireless.

[0085] The print control device 16 is composed of a computer equipped with a CPU (Central Processing Unit), a semiconductor memory, a hard disk, etc. The print control device 16 executes a print control program stored in advance in a storage medium such as a semiconductor memory or a hard disk based on an input print job, etc., and controls each part shown in FIG. 7 by operating an electric circuit.

[0086] The print control device 16 also controls the first and second pumps P1, P2 to control the discharge of cleaning liquid from the first and second cleaning liquid tanks 30c, 30d. The print control device 16 also controls the third pump P3 to control the discharge of ink from the first to fourth cap units 41-44, and controls the fourth pump P4 to control the discharge of pre-treatment liquid from the fifth cap unit 45.

[0087] Furthermore, the print control device 16 controls the first and second pumps P1, P2 to control the timing of discharging the cleaning liquid from the first and second cleaning liquid tanks 30c, 30d in accordance with the amount of liquid discharged from the first to fifth heads 11-15 to the first to fifth cap parts 41-45. Specifically, the print control device 16 controls the first and second pumps P1, P2 to discharge the cleaning liquid from the first and second cleaning liquid tanks 30c, 30d every time the number of purging operations of the first to fifth heads 11-15 reaches a preset threshold number of times.

[0088] This allows the cleaning liquid to flow effectively and efficiently through the same flow path 52 and the same flow path 53, and appropriately prevents clogging of these paths. Also, it is possible to prevent the cleaning liquid from being discharged wastefully.

[0089] Next, a printing operation of the inkjet printing apparatus 1 of this embodiment will be described. Note that, here, a case will be described in which the first head 11 is not used, and the pretreatment liquid is ejected from the fifth head 15 to apply it to the printing paper P, and then ink is ejected from the second to fourth heads 12 to 14 to print on the printing paper P to which the pretreatment liquid has been applied.

[0090] First, as shown in Figure 2, a roll of paper is placed on the supply side core holding section 9, and the roll of paper (printing paper P) is pulled out and passed through the rear paper guide 4b, between the drive roller 6 and the pressure roller 7, over the platen 4, and the front paper guide 4a, before being wound around the core 8a held by the take-up side core holding section 8.

[0091] Then, the printing control device 16 feeds out the printing paper P by rotating the supply side core holding unit 9, the winding side core holding unit 8, and the drive roller 6, and temporarily stops the feeding of the printing paper P when it reaches the initial printing position.

[0092] Next, the print control device 16 operates the main scanning drive motor 54 to move the head unit 10 in a first direction (either left or right) on the rail portion 5. Then, together with the movement of the head unit 10, the print control device 16 operates the fifth head 15 of the head unit 10 to apply the pretreatment liquid to the first scan line. Note that, when scanning the first scan line, ink is not ejected from the second to fourth heads 12 to 14.

[0093] Next, the print control device 16 advances the print paper P by one scan line so that the first scan line, to which the pretreatment liquid is applied, is positioned directly below the second to fourth heads 12 to .

[0094] Then, the print control device 16 moves the head unit 10 on the rail portion 5 in a second direction opposite to the first direction, and, with the movement, causes the second to fourth heads 12 to 14 to eject ink to print the first scan line. Furthermore, while printing the first scan line, the print control device 16 also operates the fifth head 15 to apply the pretreatment liquid to a second scan line that is next to the first scan line.

[0095] Next, the print control device 16 feeds out the printing paper P by one scan line, and places a second scan line directly below the second to fourth heads 12 to 14, and places a third scan line immediately below the fifth head 15.

[0096] Then, the print control device 16 moves the head unit 10 in the first direction on the rail portion 5, and in conjunction with the movement, operates the second to fourth heads 12 to 14 and the fifth head 15 to apply pretreatment liquid to the third scan line and print on the second scan line.

[0097] Thereafter, the printing control device 16 alternately repeats the process of feeding out one scan line of printing paper P and moving the head unit 10 on the rail portion 5 in the first direction or the second direction, in the same manner as described above, to sequentially apply pretreatment liquid to the (n+1)th scan line and print on the nth scan line.

[0098] In the above description, the operation is described when the pretreatment liquid is applied by the fifth head 15 without using the first head 11, but the base may be printed using the first head 11 without using the fifth head 15. In this case, the ink ejection timing from the first head 11 is the same as the ejection timing from the fifth head 15 described above.

[0099] Next, a maintenance operation of the inkjet printing apparatus 1 of this embodiment will be described.

[0100] The maintenance operation is carried out during a standby period when no printing process is being performed, and at this time, the head unit 10 is placed inside the maintenance unit 20 shown in FIG.

[0101] First, with the head unit 10 disposed above the capping unit 40, the head unit 10 is controlled to eject ink at a predetermined pressure, thereby carrying out purging.

[0102] During this purging, the ejection surfaces of the first to fifth heads 11 to 15 of the head unit 10 may be either sealed by the first to fifth cap parts 41 to 45 of the capping unit 40, or may be open. However, it is preferable to seal by the first to fifth cap parts 41 to 45, as sealing in this manner can prevent the intrusion of dust and other debris into the first to fifth cap parts 41 to 45 and the surroundings of the first to fifth cap parts 41 to 45 from being contaminated by ink.

[0103] Then, the ink ejected from the first to fourth heads 11 to 14 by the above-mentioned purging is received by the first to fourth cap portions 41 to 44, is discharged into the first cap side flow path 47 by the operation of the third pump P3, and is discharged into the waste liquid tank 51 via the same flow path 53. Also, the ink ejected from the fifth head 15 by the above-mentioned purging is received by the fifth cap portion 45, is discharged into the second cap side flow path 48 by the operation of the fourth pump P4, and is discharged into the waste liquid tank 50 via the same flow path 52.

[0104] After the above-mentioned purging is completed, the print control device 16 moves the head unit 10 on the rail portion 5 and positions it above the wiping unit 30.

[0105] Then, the printing control device 16 moves the first to fifth wipers 31a to 31e, which are immersed in the cleaning liquid in the first and second cleaning liquid tanks 30c and 30d, using the first and second conveyor belts 32 and 35, and positions the tips of the first to fifth wipers 31a to 31e at the front end positions of the corresponding first to fifth heads 11 to 15.

[0106] Next, the print control device 16 moves the first to fifth wipers 11 to 15 as they are, so that the tips of the first to fifth wipers 31a to 31e are pressed against the ejection surfaces of the first to fifth heads 11 to 15 and are in an elastically deformed state. At this time, in order to press the tips of the first to fifth wipers 31a to 31e against the ejection surfaces of the first to fifth heads 11 to 15, the print control device 16 may move the head unit 10 downward or move the wiping unit 30 upward.

[0107] Then, while the tips of the first to fifth wipers 31a to 31e are pressed against the ejection surfaces of the first to fifth heads 11 to 15, the print control device 16 further moves the first to fifth wipers 31a to 31e, thereby wiping the ejection surfaces of the first to fifth heads 11 to 15.

[0108] Then, after wiping is completed by moving the tip ends of the first to fifth wipers 31a to 31e to the rear ends of the first to fifth heads 11 to 15, the print control device 16 further moves the first to fifth wipers 31a to 31e so that they are again immersed in the cleaning liquid in the first cleaning liquid tank 30c and the second cleaning liquid tank 30d.

[0109] Then, after the above-mentioned wiping operation is completed, the print control device 16 moves the head unit 10 and places it above the capping unit 40. Then, the print control device 16 raises the capping unit 40 using a lifting mechanism (not shown), thereby bringing the first to fifth cap parts 41 to 45 into contact with the first to fifth heads 11 to 15 and sealing the ejection surfaces of the first to fifth heads 11 to 15. This concludes the explanation of the maintenance operation of this embodiment.

[0110] Then, when performing printing processing after the above-mentioned maintenance operation, the capping unit 40 descends and the head unit 10 moves left and right along the rail portion 5 to perform printing.

[0111] The above-mentioned maintenance operation may be performed automatically just before starting the printing process, or in response to a user's instruction input.Furthermore, it may be performed at predetermined intervals or at predetermined lengths of the printing range (the amount of print paper P fed out).

[0112] Then, as described above, each time the number of purges due to the maintenance operation reaches a preset threshold number, the printing control device 16 controls the first and second pumps P1, P2 to discharge the cleaning liquid from the first and second cleaning liquid tanks 30c, 30d, and to flow the cleaning liquid containing ink into the same flow path 53 via the first junction S1, and to flow the cleaning liquid containing pretreatment liquid into the same flow path 52 via the second junction S2.

[0113] In the above embodiment, the cleaning liquid is discharged from the first and second cleaning liquid tanks 30c, 30d each time the number of purging reaches a preset threshold number, but the timing of discharging the cleaning liquid from the first and second cleaning liquid tanks 30c, 30d is not limited to this, and for example, the cleaning liquid may be discharged from the first and second cleaning liquid tanks 30c, 30d each time a preset time has elapsed, or the cleaning liquid may be discharged from the first and second cleaning liquid tanks 30c, 30d in response to a user's instruction input.

[0114] The present invention further discloses the following supplementary notes. (Additional Note)

[0115] The liquid discharging device of the present invention can be provided with a capping section having a cap portion and a cap-side flow path, and a wiping section having a wiper, a cleaning liquid tank for storing a wiper and a cleaning liquid for cleaning the wiper, and a wiper-side flow path for discharging the cleaning liquid into the wiper-side flow path.

[0116] In the liquid discharging device of the present invention, it is preferable that the ejection section includes an inkjet head and a treatment liquid head that ejects a treatment liquid different from ink, the capping section has a cap section and a cap side flow path corresponding to the inkjet head, and a cap section and a cap side flow path corresponding to the treatment liquid head, the wiping section has a wiper, a cleaning liquid tank and a wiper side flow path corresponding to the inkjet head, and a wiper, a cleaning liquid tank and a wiper side flow path corresponding to the treatment liquid head, and has a first junction where the cap side flow path corresponding to the inkjet head and the wiper side flow path join, and a common flow path for ink is formed from the first junction, and a second junction where the cap side flow path corresponding to the treatment liquid head and the wiper side flow path join, and a common flow path for treatment liquid is formed from the second junction.

[0117] In the liquid discharging device of the present invention, it is preferable that the same flow passage extending from the junction is longer than the cap side flow passage and the wiper side flow passage.

[0118] Furthermore, the liquid discharging device of the present invention can be provided with a discharge section that discharges the cleaning liquid from the cleaning liquid tank, and a control section that controls the discharge section, and the control section can control the timing of discharging the cleaning liquid by controlling the discharge section according to the amount of liquid discharged from the discharge section to the cap section.

[0119] An inkjet printing apparatus of the present invention includes the above-described liquid discharging device, and performs printing by discharging ink from the discharging portion onto a printing medium. [Explanation of symbols]

[0120] 1 Inkjet printing device 2 Base 2a wheels 3 pedestal 4 Platen 4a Front paper guide 4b Rear paper guide 4c Vacuum chamber 4d fan 5 Rail section 6 Drive roller 7 Pressure roller 8. Winding side core holder 8a Core body 9 Supply side core holding part 9a Core body 10 Head Unit 11~15 Heads 1~5 16 Printing control device 20 Maintenance Unit 30 Wiping unit 30a Cleaning solution tank 30b Bulkhead 30c First cleaning solution tank 30d Second cleaning solution tank 31a to 31e 1st to 5th wipers 32 First conveyor belt 33 First belt conveyor roller 34 Second belt conveyor roller 35 Second conveyor belt 37 Second wiper side passage 38 First wiper side passage 39 Belt drive motor 40 Capping Unit 40a plate material 41~45 1st to 5th cap parts 41a Foundation 41b Capping member 41c bottom 41d Peripheral wall 41e Discharge hole 46 Discharge path section 47 First cap side flow path 48 Second cap side flow path 50 Waste Liquid Tank 51 Waste liquid tank 54 Main scanning drive motor 52,53 Same line 61 Transport drive motor 81 Winding drive motor 91 Supply drive motor L Cleaning Solution P Print paper P1 First pump P2 Second pump P3 3rd pump P4 4th pump S1 First Junction S2 Second Junction

Claims

1. a first cap side flow path through which ink is discharged into a first cap portion that seals an ink ejection port of an inkjet head having an ink ejection port for ejecting ink; a second cap side flow path through which the treatment liquid discharged into a second cap portion that seals a treatment liquid discharge port of a treatment liquid head having a treatment liquid discharge port that discharges a treatment liquid different from ink; a first wiper-side flow path through which a cleaning liquid used for wiping the ink ejection ports of the inkjet head is discharged from a first cleaning liquid tank that stores the cleaning liquid; a second wiper-side flow path through which a cleaning liquid used for wiping the processing liquid discharge port of the processing liquid head is discharged from a second cleaning liquid tank in which the cleaning liquid is stored, A liquid discharge device having a first junction where the first cap side flow path and the first wiper side flow path join, from which a common flow path for ink is formed, and a second junction where the second cap side flow path and the second wiper side flow path join, from which a common flow path for treatment liquid is formed.

2. a capping portion having the first cap portion, the second cap portion, the first cap side flow path, and the second cap side flow path; 2. The liquid discharging device according to claim 1, further comprising a wiping section having the first cleaning liquid tank, the second cleaning liquid tank, the first wiper-side flow path and the second wiper-side flow path.

3. a cap-side flow path through which the discharged liquid is discharged into a cap portion that seals the discharge port of a discharge portion having the discharge port for discharging the liquid; a wiper-side flow path through which cleaning liquid is discharged from a wiping portion that wipes the discharge port of the discharge portion, A liquid discharge device having a junction where the cap-side flow path and the wiper-side flow path join together, the junction forming a common flow path, a liquid discharge device in which the same flow path extending from the junction is longer than the cap side flow path and the wiper side flow path;

4. a cap-side flow path through which the discharged liquid is discharged into a cap portion that seals the discharge port of a discharge portion having the discharge port for discharging the liquid; a wiper-side flow path through which cleaning liquid is discharged from a wiping portion that wipes the discharge port of the discharge portion, A liquid discharge device having a junction where the cap-side flow path and the wiper-side flow path join together, the junction forming a common flow path, The cleaning device further includes a discharge unit that discharges the cleaning liquid from a cleaning liquid tank that is provided in the wiping unit and in which the cleaning liquid is stored, and a control unit that controls the discharge unit, The control unit controls the discharge unit in accordance with the amount of liquid discharged from the discharge unit to the cap unit, thereby controlling the timing of discharging the cleaning liquid.

5. An inkjet printing device comprising the liquid ejection device according to any one of claims 1 to 4.

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