JP6752742B2 - Inkjet printing equipment - Google Patents

Description

The present invention relates to an inkjet printing apparatus that ejects ink from an inkjet head to a printing medium to print.

The inkjet printing apparatus is provided with a cap that can seal the nozzle surface in order to prevent the ink on the nozzle surface of the inkjet head from drying out. In addition, when it is assumed that the device will not be used for a long period of time, fill cap control is performed in which the nozzle surface of the inkjet head is covered with a cap to create a sealed state, and then the inside of the cap is filled with ink. ..

As a technique of covering with a cap in order to prevent the inkjet head from drying, for example, there is one disclosed in Patent Document 1. The technique of Patent Document 1 has multiple ribs that come into contact with the face surface of the inkjet recording head of the cap in order to prevent a decrease in the drying prevention ability due to the displacement of the cap of the capping device.

JP-A-7-125243

Insufficient cleaning of the inside of the cap could cause ink to stick to the inside of the cap, especially the edges.

In addition, when the ink is left for a long period of time after controlling the fill cap, the thin film ink may stick to the portion where the nozzle plate and the cap, which are the ejection surfaces of the inkjet head, are in close contact with each other.

These sticking inks may not be completely removed even if they are manually cleaned or automatically cleaned, and then when the inkjet head is capped, poor sealing will occur and the nozzle surface will dry out. In some cases, it could not be sufficiently suppressed.

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 capable of easily removing stains inside a cap of an inkjet head.

In order to achieve the above object, the first feature of the inkjet printing apparatus according to the present invention is an inkjet head having a nozzle for ejecting ink, two caps that come into contact with the inkjet head and cover the nozzle, and the two caps . A cap base that holds the cap on the outer peripheral surface and is rotatable about an axis parallel to the arrangement direction of the nozzles, a cleaning liquid tank that stores the cleaning liquid, a drive unit that rotates the cap base, and the drive. part drives, the during the standby state for sealing the nozzle surface of the inkjet head by one of two caps, so that a state where the other one cap is immersed in the cleaning liquid of the cleaning solution tank Is provided with a control unit that controls the positional relationship between the inkjet head, the cap, and the cleaning liquid tank.

The second feature of the inkjet printing apparatus according to the present invention is that when the control unit shifts to the standby state, the cap time during which the inkjet head is covered with the cap continues longer than a predetermined time. When it is determined that the cap is immersed in the cleaning liquid tank, the driving unit is controlled so as to be a cap immersed in the cleaning liquid tank.

According to the first feature of the inkjet printing apparatus according to the present invention, when the inkjet head is capped with a cap, another cap is immersed in the cleaning liquid. Therefore, even if the ink that could not be removed remains on the cap, it is possible to easily remove the remaining stains at the next manual cleaning by the user or automatic cleaning by the device. As a result, the cap used for capping can be kept cleaner than before, and drying of the nozzle due to poor capping can be suppressed.

According to the second feature of the inkjet printing apparatus according to the present invention, the cap that has been in the capped state for a long time is not used for capping the inkjet head at the next capping. Further, the cap that has been in the capped state for a long time while capping with another cap will be transferred to the standby state while being immersed in the cleaning liquid. As a result, in addition to the effect of the first feature, even if dirt remains in the cap in the previous cleaning (cleaning), it is possible to easily remove the dirt in the next cleaning (cleaning).

It is an overall perspective view of the inkjet printing apparatus which concerns on this embodiment. It is a front view which shows typically the schematic structure of the inkjet printing apparatus. It is a schematic block diagram of the cap mechanism part of the inkjet printing apparatus. It is a figure which shows the capping state by a cap, and the state of being immersed in a cleaning liquid. It is a schematic perspective view of the main part of a cap mechanism part. It is a control block diagram of an inkjet printing apparatus. It is a flowchart for demonstrating operation of this Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings.

The embodiments shown below exemplify an apparatus or the like for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, arrangement, etc. of each component. Is not specified as the following. The technical idea of the present invention can be modified in various ways within the scope of claims.

FIG. 1 is an overall perspective view of the inkjet printing apparatus. FIG. 2 is a front view schematically showing a schematic configuration of an inkjet printing apparatus. FIG. 3 is a schematic configuration diagram of a cap mechanism portion of an inkjet printing apparatus. FIG. 4 is a diagram showing a capped state by the cap and a state of being immersed in the cleaning liquid. FIG. 5 is an abbreviated perspective view of a main part of the cap mechanism portion. FIG. 6 is a control block diagram of the inkjet printing apparatus. In the following description, the up / down / left / right / front / rear directions indicated by the arrows in FIG.

As shown in FIGS. 1, 2, and 6, the inkjet printing apparatus 1 according to the present embodiment includes a shuttle base unit 2, a flatbed unit 3, a shuttle unit 4, a control unit 5, and a timer 6. Be prepared.

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

The gantry portion 11 supports the shuttle unit 4. The gantry portion 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 portion 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 flatbed unit 3 holds a printing medium 15 made of a base material such as a building material or a decorative panel. The flatbed unit 3 is arranged inside the gantry portion 11 of the shuttle base unit 2. The flatbed unit 3 has a medium mounting surface 3a which is a horizontal plane on which the printing medium 15 is mounted. The flat bed unit 3 can adjust the height of the medium mounting surface 3a by an elevating mechanism including a hydraulic drive mechanism or the like.

The shuttle unit 4 prints an image on the print medium 15. As shown in FIGS. 1, 2, and 6, the shuttle unit 4 includes a housing 21, a main scanning drive guide 22, a main scanning drive motor 23, a head elevating guide 24, a head elevating motor 25, and a head. A unit 26, a cap mechanism portion 27, and a wipe portion 28 are provided.

The housing 21 houses various parts such as the head unit 26. The housing 21 is formed in a gate shape straddling the flatbed unit 3 in the left-right direction. The housing 21 is supported by the gantry portion 11 of the shuttle base unit 2 and can move along the sub-scanning drive guides 13A and 13B.

The main scanning drive guide 22 guides the head unit 26 so as 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 elevating guide 24 guides the head unit 26 so as to move in the vertical direction. The head elevating guide 24 is formed in an elongated shape in the vertical direction. The head elevating guide 24 and the head unit 26 are configured to be movable in the left-right direction along the main scanning drive guide 22.

The head elevating motor 25 raises and lowers the head unit 26.

The head unit 26 ejects ink to the printing medium 15 and prints an image 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 ejects water-based ink to the print medium 15. The four inkjet heads 31 are arranged side by side 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 open to the ejection surface 31a, which 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 nozzle of the inkjet head 31 and performs capping so that the space where the nozzle opens is a closed space. The cap mechanism portion 27 is arranged inside the right end portion of the housing 21. As shown in FIGS. 2 to 5, the cap mechanism 27 includes four cap units 41, four pumps 42, four atmospheric release valves 43, a waste liquid tank 44, a cap lifting motor 45, and cap rotation. It includes a drive unit 46 and a cleaning liquid tank 47. Note that FIG. 3 shows a configuration corresponding to one inkjet head 31 as a representative for a portion having the same configuration provided corresponding to each inkjet head 31. Further, in FIG. 5, since the cap 50a provided on the first surface and the cap 50b provided on the second surface of the cap base 52 are the same, the parts having the same configuration related thereto are represented. The configuration corresponding to one cap 50a is shown.

The cap unit 41 includes caps 50a and 50b, a cap base 52, a suction pipe 53, an air release pipe 54, and a worm 55. The cap base 52 is provided with caps 50a and 50b having the same shape on the front and back surfaces, respectively. Not limited to the front and back sides, a plurality of caps 50 may be formed around the cap base 52.

The caps 50a and 50b are members that abut and cap the ejection surface 31a of the inkjet head 31.

The cap 50a includes an oval-shaped ink receiving surface 56 at the bottom and a peripheral wall 57 erected on the peripheral edge of the ink receiving surface 56. The ink receiving surface 56 is provided with a suction hole 56a1 for sucking air, ink, etc. from the space inside the cap 51, and an atmosphere opening hole 56a2 for opening the space inside the cap 51 to the atmosphere. The peripheral wall 57 is formed in a shape that surrounds all the nozzles when it comes into contact with the ejection surface 31a of the inkjet head 31. The end of the peripheral wall 57 on the opening side opposite to the ink receiving surface 56 side forms the opening end 51a of the cap 50a.

A plurality of caps 50 are provided on the outer peripheral surface of the cap base. In this embodiment, as shown in FIGS. 3 and 4, two caps 50a and 50b are provided, and the 50a and 50b have the same shape.

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 caps 50a and 50b on the front surface 52a side and the back surface 52b side, respectively.

By rotating the cap base 52 by the cap rotation drive unit 46 and inverting the front and back, the control unit 5 controls the caps 50a and 50b so that they are selectively opposed to the discharge surface 31a of the inkjet head 31.

The suction pipe 53 constitutes a flow path for air, ink, and the like sucked from the space inside the caps 50a and 50b. One end of the suction pipe 53 is connected to the waste liquid tank 44. Further, the other end of the suction pipe 53 is branched into two on the cap 50a side of the pump 42. One end of the two branched suction tubes 53 is connected to the suction hole 56a1 of the cap 50a having the opening end 51a, and the other end is connected to the suction hole 56b1 of the cap 50b having the opening end 51b. ..

Further, a valve 71A and a valve 71B are arranged in the branched pipes of the suction pipe 53, respectively. The valve 71A is arranged between the branch point of the suction pipe 53 and the suction hole 56a1 of the cap 50a provided with the opening end 51a, and opens and closes the flow path in the suction pipe 53 in that section. The valve 71B is arranged between the branch point of the suction pipe 53 and the suction hole 56b1 of the cap 50b provided with the opening end 51b, and opens and closes the flow path in the suction pipe 53 in that section.

The atmosphere opening pipe 54 constitutes an air flow path for communicating the space inside the cap 50a with the atmosphere from the ink receiving surface 56 side. An atmosphere release valve 43 is connected to one end (atmosphere open end) of the atmosphere release pipe 54. Further, at the other end of the air opening pipe 54 on the cap 50a side, one pipe is branched in the middle, and air for communicating the space inside the caps 50a and 50b with the atmosphere from the ink receiving surface 56 side, respectively. In order to form the flow path of the above, the air opening holes 56a2 provided on the ink receiving surface 56 on the cap 50a side and the air opening holes 56b2 provided on the ink receiving surface 56 on the cap 50b side are connected.

Further, a valve 72A and a valve 72B are arranged in the branched pipes of the atmosphere opening pipe 54, respectively. The valve 72A is arranged between the branch point of the atmospheric opening pipe 54 and the atmospheric opening hole 56a2 of the cap 50a, and opens and closes the flow path in the atmospheric opening pipe 54 in that section. The valve 72B is arranged between the branch point of the atmospheric opening pipe 54 and the atmospheric opening hole 56b2 of the cap 50b, and opens and closes the flow path in the atmospheric opening pipe 54 in that section.

Although the suction hole 56b1 and the atmosphere opening hole 56b2 are not shown, they are provided at the same positions as the suction hole 56a1 and the atmosphere opening hole 56a2 with the cap base 52 interposed therebetween.

The worm 55 rotates by the driving force of the cap rotation driving unit 46, thereby rotating 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 inside the caps 50a and 50b. 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 holes 56a1 and the suction holes 56b1 of the caps 50a and 50b via the suction pipe 53.

The atmosphere release valve 43 opens and closes the opening of the atmosphere opening end of the atmosphere opening pipe 54. When the air release valve 43 is in the open state, the atmosphere release pipe 54 communicates with the atmosphere from the atmosphere open end through the suction hole 56a2 or the suction hole 56b2 on the side where the valve 72A or the valve 72B is opened, and the atmosphere release valve 43 When is closed, the atmosphere opening pipe 54 is shut off from the atmosphere at the atmosphere opening 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 motor 45 raises and lowers the four cap units 41 and the cap rotation drive unit 46.

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 about a rotation axis (not shown) extending in the left-right direction to rotate the worm 55. One worm wheel 58 is arranged in each of the four cap units 41. Four worm wheels 58 are fixed to a common rotation shaft.

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

The cleaning liquid tank 47 stores the cleaning liquid for cleaning the caps 50a and 50b. The cleaning liquid tank 47 is arranged below the cap base 52.

In order to immerse the caps 50 and 50b in the cleaning liquid tank 47, the control unit 5 caps the inkjet head 31 with either the cap 50a or 50b, and then uses the head elevating motor 25 and the cap elevating motor 45 to cap the head unit 26 and the cap. Lower the unit 41 by the same distance. As a result, while the inkjet 31 and either the cap 50a or 50b are kept in a sealed state, the other cap 50a or 50b that is not used for capping reaches the cleaning liquid tank 47 and is immersed. In this state, while the inkjet head 31 is capped by one cap 50, the other cap 50 is immersed in the cleaning liquid of the cleaning liquid tank 47. Therefore, the immersed cap 50 is cleaned or washed next time. It is possible to make it easier to remove dirt inside the cap.

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

Examples of the surfactant include sodium fatty acid, sodium alkylbenzene sulfonate, sodium alkyl sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfate, sodium alkyl ether sulfate, sodium α-sulfo fatty acid ester, and sodium alkyl phosphate. Anionic surfactants such as; cationic surfactants such as alkyltrimethylammonium, 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 ether; amphoteric surfactants such as alkylamino fatty acid sodium, alkylbetaine and alkylamine oxide can be used. Further, a polymer-based surfactant, a silicone-based surfactant, a fluorine-based surfactant, an acetylene glycol-based surfactant, and the like 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 carbon number of the alkyl group is 8 to 15, and the number of moles of ethylene oxide added is 6 to 25.

The cleaning liquid preferably further contains a thickener. As the thickener, a water-soluble polymer-based thickener and a clay mineral-based thickener can be used. As the water-soluble polymer-based thickener, a natural polymer, a semi-synthetic polymer, or a synthetic polymer can be used. Examples of natural polymers include plant-based natural polymers such as Arabic gum, carrageenan, guar gum, locust bean gum, pectin, tragant gum, corn starch, konjac mannan, and agar; microbial natural polymers such as pullulan, xanthan gum, and dextrin; Animal-based natural polymers such as gelatin, casein, and konjac can be used. Examples of the semi-synthetic polymer include cellulose-based semi-synthetic polymers such as ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, and hydroxypropyl methyl cellulose; starch-based polymers such as hydroxyethyl starch, carboxymethyl starch sodium, 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 polyvinylpyrrolidone, polyvinyl alcohol, polyvinylmethyl 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 hydroxypropylmethyl cellulose.

Further, in addition to the above-mentioned components, the cleaning liquid may 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, more preferably 10 to 100 mPa · s at 23 ° C.

The wipe portion 28 wipes the discharge surface 31a of the inkjet head 31 during maintenance of the inkjet head 31. The wipe portion 28 is arranged 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 discharge surface 31a of the inkjet head 31. The wiper 61 is made of a material such as rubber that can be elastically deformed.

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

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

The control unit 5 rotates the cap base 52 by the cap rotation drive unit 46 to make the desired cap of the cap 50 face the cleaning liquid tank 47 and the inkjet head 31. Further, the control unit 5 drives the head elevating motor 25 and the cap elevating motor 45 to control the relative positional relationship between the inkjet head 31, the cap 50, and the cleaning liquid tank 47.

Further, when cleaning the cap 50, if the cap to be cleaned is 50a, the control unit 5 drives the pump 42 with the cap 50a immersed in the cleaning liquid to suck the cleaning liquid from the suction hole 56a1. The pump 42 is driven in the reverse direction of the time of suction to control the cleaning liquid sucked into the suction pipe 53 to be discharged from the suction hole 56a1. If the object to be cleaned is the cap 50b, the 50b is cleaned using the suction hole 56b1 with the cap 50a immersed in the cleaning liquid.

At this time, the control unit 5 opens the valve 71A and the valve 71B that are connected to the cap 50 to be cleaned, and closes the one that is connected to the cap 50 that is not the target. Control the opening and closing of.

The timer 6 keeps time. The control unit 5 acquires the time from the timer 6 as needed, and stores the necessary values in a storage medium such as a hard disk.
<Printing operation>

Next, the printing operation of the inkjet printing apparatus 1 will be described with reference to FIG. 7.

In the inkjet printing apparatus 1, the shuttle unit 4 is arranged 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 shown by the solid line in FIG. 1, and is located at the rear end of the gantry portion 11 of the shuttle base unit 2.

Further, in the standby state of the inkjet printing device 1, the head unit 26 is arranged at a home position away from the printing start position. In this state, the inkjet head 31 is capped by either the cap 50a or 50b, and the other cap 50 is immersed in the cleaning liquid of the cleaning liquid tank 47.

When the printing process is started, the control unit 5 drives the head elevating motor 25 to release the capping between the inkjet head 31 and the cap 50a. Here, it is assumed that the cap 50a has been capped. Further, before executing the subsequent steps, the control unit 5 executes a cap cleaning operation described later.

Next, 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 print processing start position of the shuttle unit 4 is the position of the shuttle unit 4 shown by the alternate long and short dash line in FIG. 1, and is located at the front end of the gantry portion 11 of the shuttle base unit 2. Prior to inputting the print job, the print medium 15 is placed on the medium mounting surface 3a of the flatbed unit 3.

At this time, the control unit 5 caps the inkjet head 31 until just before by driving the cap elevating motor 45 and the cap rotation motor 59 in parallel with the process of moving to the above-mentioned printing process start position (step S1). The cap 50a that has been used is immersed in the cleaning liquid tank 47, and a cap cleaning operation described later is executed (step S2).

Further, the control unit 5 acquires the current time from the timer 6 and the capping start time stored in a storage medium such as an HDD, and determines the time during which the cap 50a is in the standby state (hereinafter referred to as the cap time). Acquire (step S3).

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 inkjet head 31 based on the print job to eject ink from the nozzles, thereby performing one pass. Print the 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 control unit 5 forms an image on the print medium 15 and executes the printing process by alternately repeating printing for one pass and moving the shuttle unit 4 (step S4).

When the printing of one sheet is completed (step S5: Yes), the control unit 5 controls the main scanning drive motor 23 to arrange the head unit 26 in the home position.

Then, the control unit 5 determines whether or not the cap time acquired in step S3 is longer than the predetermined time (step S6). When the cap time is longer than a predetermined time (step S6: Yes), the dirt inside the cap 50a may not be completely removed even if the cap cleaning process described later is executed. If this dirt is left unattended, the adhesion state cannot be ensured even if the capping process is performed, and drying of the nozzle surface of the inkjet head 31 may not be suppressed. Therefore, in order to facilitate the removal of dirt, the control unit 5 determines in step 6 whether or not it is necessary to continue the state in which the cap 50a that capped the inkjet head 31 immediately before is immersed in the cleaning liquid tank 47. To do.

When the control unit 5 determines that step S6 is Yes, the control unit 5 controls the cap rotation motor 59 so that the cap 50a is immersed in the cleaning liquid tank 47 in the standby state, and the cap 50a and the cleaning liquid tank 47. To face each other. Then, the control unit 5 drives the cap elevating motor 45 to move the cap unit 41 up and down so that the inkjet head 31 and the cap 50b facing each other come into contact with each other. After that, the control unit 5 drives the head elevating motor 25 and the cap elevating motor 45 by the same distance to lower both the head unit 26 and the cap unit 41, and keeps the cap 50a immersed in the cleaning liquid tank 47. (Step S7).

If No is determined in step S6, the inkjet head 31 may be capped by any cap 50 (step S8). It is conceivable to use caps 50a and 50b alternately. Further, as in step 7, in the standby state, the control unit 5 is headed so that the inkjet head 31 is capped by one cap and the other cap is immersed in the cleaning liquid of the cleaning liquid tank 47. Drives the elevating motor 25 and the cap elevating motor 45, and controls the positional relationship between the inkjet head 31, the caps 50a and b, and the cleaning liquid tank 47.

After that, when the control unit 5 determines that the capping state of S7 or S8 is continued for a long time, the control unit 5 executes fill cap control to prevent the nozzle surface from drying. For example, the time when the control unit 5 does not receive the print job is longer than a predetermined time, or the power of the device is turned off.

Further, the control unit 5 stores the time of capping in step 7 or step 8 or the time of fill cap control in a storage medium such as hardware. At the time of the next printing operation, the control unit 5 uses this time information for the determination in step S6.
<Cap cleaning operation>

Next, a cap cleaning operation (also referred to as a cap cleaning process) in the inkjet printing apparatus 1 will be described.

When the unprinted state continues for a long period of time, the cap cleaning operation is performed following the release of the fill cap state when the power of the inkjet printing apparatus 1 is turned on.
When the power of the inkjet printing apparatus 1 is turned on, the control unit 5 opens the atmospheric release valve 43, opens the valve 71A, drives the pump 42, and caps the cap that was in the capping state until just before. The ink in the space within 50a is discharged from the suction hole 56a1. When the discharge of ink in the space inside the cap 51 is completed, the fill cap state is released.

When the fill cap state is released, the control unit 5 starts the cap cleaning operation.

The cap cleaning operation will be specifically described. The control unit 5 controls the cap elevating motor 45 to move the cap unit 41 from the capping position to the retracted position. Here, the retracted position of the cap unit 41 is a position immediately above the cleaning liquid tank 47, and when the cap base 52 is rotated and turned upside down, the cap 50a, which was in the fill cap state until just before, becomes the cleaning liquid of the cleaning liquid tank 47. It is in a position where it can be immersed.

Next, the control unit 5 controls the cap rotation motor 59 to rotate the cap base 52, and then immerses the cap 50a in the cleaning liquid of 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 is in a state where the surface 52a faces downward.

Next, the control unit 5 drives the cap elevating motor 45 to lower the cap unit 41 until the cap 50a, which has been capped until just before, is immersed in the cleaning liquid of the cleaning liquid tank 47. At this time, at least the open end 51a of the cap 50a may be immersed in the cleaning liquid.

Next, after closing the atmospheric release valve 43, the control unit 5 opens the valve 71A and drives the pump 42 to suck the cleaning liquid from the suction hole 56a1 into the suction pipe 53.

Next, the control unit 5 drives the pump 42 in the reverse direction of the suction in step S3, and discharges the cleaning liquid sucked into the suction pipe 53 from the suction hole 56a1. After that, the control unit 5 opens the atmosphere release valve 43.

The control unit 5 maintains a state of being immersed in the cleaning liquid tank 47. As a result, the cap cleaning operation is completed.

By immersing the cap 50 in the cleaning liquid by such a cap cleaning operation, the ink adhering to the cap 50 can be washed away in the fill cap state. Further, by sucking and discharging the cleaning liquid from the suction hole 56a1 by driving the pump 42, the ink adhering to the suction hole 56a1 can also be washed away.

As a result, it is possible to prevent the ink from sticking to the peripheral wall 57 of the cap 50a and the suction hole 56a1. Further, even if there is ink stuck to the peripheral wall 57 of the cap 50a or the suction hole 56a1, it can be melted with a cleaning liquid and washed away.

Further, the suction and discharge of the cleaning liquid from the suction hole 56a1 agitates the cleaning liquid in the cleaning liquid tank 47 and causes the cleaning liquid to move, so that the ink adhering to the cap 50a 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 power of the inkjet printing apparatus 1 is turned on, and may be performed at other timings. For example, it may be performed during the printing operation.

As described above, since the inkjet printing apparatus 1 is provided with a plurality of caps 50 capable of capping the inkjet head 31 around the cap base 52, the inkjet head 31 is capped by one cap 50 in the standby state. The other cap 50 can be immersed in the cleaning liquid tank 47. By immersing the ink in the cleaning liquid, even if the ink is stuck to the immersed cap 50, it can be easily removed.

Further, when the cap time in which the previous capping was continued is longer than a predetermined time when shifting to the standby state, the control unit 5 rotates the cap base 52 by the cap rotation drive unit 46 to rotate the cap base 52 last time. The cap 50 that capped the inkjet head 31 is immersed in the cleaning liquid of the cleaning liquid tank 47, and the inkjet head 31 is capped using another cap 50. This makes it easier to remove the ink remaining in the cap 50 at the next cleaning.

Further, as a cleaning operation, the control unit 5 drives the pump 42 with the cap 50a immersed in the cleaning liquid to suck the cleaning liquid from the suction hole 56a1 into the suction pipe 53, and then drives the pump 42 in the reverse direction of the suction. Then, the cleaning liquid sucked into the suction pipe 53 is controlled to be discharged from the suction hole 56a1. As a result, the cap 50a can be cleaned by immersing it in the cleaning liquid, and the ink adhering to the suction hole 56a1 can be removed by sucking and discharging the cleaning liquid from the suction hole 56a1. Therefore, according to the inkjet printing apparatus 1, insufficient cleaning of the cap 50 can be reduced.

It should be noted that this cleaning operation is not essential. It is possible to apply the present invention even in a device in which the user manually cleans the cap 50.

Further, in step S6, although the determination is made only by whether or not the cap time is longer than the predetermined time, the time during which the cap 50 is immersed in the cleaning liquid tank 47 and the number of cap cleaning treatments may be included. , These may be used alone.

Further, before the process of step S7 or step S8 described above, the cap rotation motor 45 may be driven by the control unit 5 to rotate the cap base 52 by 360 degrees × N (N is an integer of 1 or more). As a result, the caps other than the caps immersed in the cleaning liquid tank 47 in steps S7 and S8 can be rinsed with the cleaning liquid at least once, making it easier to remove the ink in the caps. it can. It is also possible to clean the dirt adhering to the inside of the cap and the outside of the cap due to the mist generated during the printing operation.

The present invention is not limited to the above embodiment as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. In addition, components across different embodiments may be combined as appropriate.

For example, when a cleaning liquid tank elevating motor for raising and lowering the cleaning liquid tank 47 is installed and the cap 50 is immersed in the cleaning liquid tank 47 in a standby state, or when the cleaning liquid tank 47 is separated from the inkjet head 31 and the capping unit 41, this is used. The control unit 5 may control the positional relationship between the cleaning liquid tank, the cap unit, and the inkjet head by using the cleaning liquid tank elevating motor. Further, the control unit 5 may cooperate with the head elevating motor 25, the cap elevating motor 45, and the cleaning liquid tank elevating motor to control the relative positional relationship between the cleaning liquid tank, the cap unit, and the inkjet head.

1 Ink printing device 2 Shuttle base unit 3 Flatbed unit 4 Shuttle unit 5 Control unit 6 Timer 26 Head unit 27 Cap mechanism 28 Wipe 41 Cap unit 42 Pump 43 Air release valve 45 Cap lift motor 46 Cap rotation drive 47 Cleaning liquid Tanks 50a, 50b Caps 51a, 51b Open end 52 Cap base 53 Suction tube 54 Atmospheric opening tube 56 Ink receiving surface 57 Peripheral wall 56a1,56b1 Suction hole 56a2, 56b2 Atmospheric opening hole 59 Cap rotary motor

Claims (2)

An inkjet head with a nozzle that ejects ink,
Two caps that come into contact with the inkjet head and cover the nozzle,
A cap base that holds the two caps on the outer peripheral surface and is rotatable about an axis parallel to the arrangement direction of the nozzles.
A cleaning liquid tank that stores the cleaning liquid and
A drive unit that rotates the cap base and
Driving the drive unit, during a standby state for sealing the nozzle surface of the inkjet head by one of the two caps, a state where the other one cap is immersed in the cleaning liquid of the cleaning solution tank A control unit that controls the positional relationship between the inkjet head, the cap, and the cleaning liquid tank so as to be
An inkjet printing apparatus characterized by being equipped with. When the control unit determines that the cap time covered by the cap has continued for longer than a predetermined time when shifting to the standby state, the control unit puts the cap in the cleaning liquid tank. The inkjet printing apparatus according to claim 1, wherein the drive unit is controlled so as to be a cap to be immersed.