JP6233389B2 - Liquid discharge apparatus and discharge head cleaning method - Google Patents

Description

  The present invention relates to a technique for cleaning a nozzle formation surface of a discharge head that discharges a liquid, and particularly to a technique for wiping a nozzle formation surface with a wiping member using a cleaning liquid.

  2. Description of the Related Art Conventionally, liquid ejecting apparatuses such as inkjet printers that eject liquid such as ink from nozzles of an ejection head are known. In such an apparatus, the liquid discharged from the nozzle may adhere to the nozzle formation surface of the discharge head. When the liquid adheres to the nozzle forming surface, the liquid is not properly discharged from the nozzle, which may cause deterioration in image quality. Accordingly, various techniques for removing the liquid adhering to the nozzle formation surface of the ejection head have been proposed.

  For example, the head cleaning mechanism disclosed in Patent Document 1 is provided with a cleaning unit including an ejection unit that ejects a cleaning liquid onto the nozzle formation surface and a wiping member in order to remove liquid adhering to the nozzle formation surface. Then, when cleaning the nozzle forming surface, the ejection head is moved in a direction to retract from the platen. In the process, when the ejection head passes through the region facing the cleaning unit, the wiping member wipes the nozzle forming surface after the cleaning liquid is sprayed onto the nozzle forming surface by the spraying means, so that the nozzle forming surface is Washed.

JP 2009-233896 A

  Here, in order to effectively clean the nozzle formation surface using the cleaning liquid, the cleaning liquid needs to be sufficiently spread on the nozzle formation surface. However, in the head cleaning mechanism of Patent Document 1, since the wiping member only wipes the nozzle forming surface once in one direction after the cleaning liquid is jetted onto the nozzle forming surface, the cleaning liquid is not sufficiently spread and effective. There was a risk that cleansing would not be performed.

  The present invention has been made in view of the above problems, and when wiping the nozzle forming surface of the ejection head using a cleaning liquid, effective cleaning can be performed by sufficiently spreading the cleaning liquid on the nozzle forming surface. The purpose is to provide technology.

  In order to achieve the above object, a liquid discharge apparatus according to the present invention has a discharge head having a nozzle formation surface on which nozzles for discharging liquid are formed, and a nozzle formation surface in contact with the nozzle formation surface. A wiping member that performs wiping by relative movement, a cleaning liquid supply unit that supplies a cleaning liquid to be used for wiping, and a wiping member that holds the cleaning liquid supplied from the cleaning liquid supply unit are arranged along a nozzle forming surface. And a control unit that performs reciprocal wiping control for performing wiping by performing reciprocal movement that performs relative movement in a second direction opposite to the first direction following relative movement in the direction.

  According to another aspect of the present invention, there is provided a discharge head cleaning method comprising: a discharge head having a nozzle formation surface on which a nozzle for discharging a liquid is formed; and forming a nozzle in contact with the nozzle formation surface. A cleaning method for an ejection head in a liquid ejection apparatus having a wiping member that performs wiping by moving relative to a surface, the cleaning liquid supplying process supplying a cleaning liquid used for wiping, and the cleaning liquid supplying process Wiping is performed by causing the wiping member holding the cleaning liquid to reciprocate in the second direction opposite to the first direction following the relative movement in the first direction along the nozzle formation surface. And a wiping step.

  In the invention thus configured (liquid ejection apparatus and ejection head cleaning method), wiping is performed by moving the wiping member relative to the nozzle formation surface in a state where the wiping member is in contact with the nozzle formation surface. And the nozzle formation surface is cleaned suitably by using the cleaning liquid used for wiping. At this time, according to the present invention, the wiping member holding the supplied cleaning liquid is moved relative to the second direction opposite to the first direction following the relative movement in the first direction along the nozzle forming surface. Wiping is performed by reciprocating movement. In other words, after the cleaning liquid is supplied, the wiping member holding the cleaning liquid performs a reciprocating operation in which the cleaning liquid relatively moves in both the first direction and the second direction, so that the cleaning liquid is sufficiently spread on the nozzle formation surface. As a result, effective cleaning using the cleaning liquid becomes possible. Note that the cleaning liquid may be directly supplied to the wiping member, or may be supplied to the wiping member via another member.

  In such a liquid ejecting apparatus, it is preferable that the controller causes the wiping member to perform a reciprocating operation a plurality of times in the reciprocating wiping control. As described above, the wiping member reciprocates a plurality of times, so that the cleaning liquid can be spread more suitably. At the same time, since the force by the wiping member is applied to the foreign matter such as the liquid adhering to the nozzle forming surface a plurality of times from both the first direction and the second direction, suitable scraping can be realized.

  In addition, in the reciprocating wiping control, the control unit performs low speed control in which the first relative movement of the wiping member in at least the first direction is performed at the first speed, and relative movement of the wiping member after the low speed control is performed at the first speed. It is preferable to execute high-speed control that is executed at a higher second speed. As described above, the low-speed control in which the speed of the wiping member is relatively low is executed at the initial stage of wiping, so that the cleaning liquid can be firmly spread on the nozzle forming surface. In addition, since the high speed control is performed after the low speed control is performed, it is possible to suppress an increase in the time required for wiping as a whole.

  Further, it is preferable that the control unit further executes cleaning control for performing wiping without supplying the cleaning liquid after discharging the liquid from the nozzle after performing the reciprocating wiping control. In the cleaning control, first, the cleaning liquid that has entered the nozzle during the wiping by the reciprocating wiping control can be discharged from the nozzle by discharging the liquid from the nozzle. Subsequently, by performing wiping without using the cleaning liquid in the cleaning control, it is possible to clean the nozzle forming surface that is soiled by the discharge of the liquid while avoiding the entrance of the cleaning liquid into the nozzle.

  In this case, it is preferable that the control unit makes the contact force with which the wiping member comes into contact with the nozzle forming surface at the time of wiping by the reciprocating wiping control larger than the contact force at the time of wiping by the cleaning control. While it is necessary to spread the cleaning liquid at the time of wiping by the reciprocating wiping control, this is not necessary because the cleaning liquid is not supplied at the time of wiping by the cleaning control. Therefore, by relatively increasing the contact force of the wiping member against the nozzle forming surface during reciprocal wiping control, the cleaning liquid can be more suitably spread while being pressed against the nozzle forming surface.

  In addition, a recess is formed in a region where the nozzle is not formed on the nozzle forming surface, and the control unit causes the wiping member to reciprocate so that the wiping member passes over the recess when wiping is performed by reciprocating wiping control. Good. For example, as such a recess, when the ejection head has a unit head provided with a nozzle and a housing in which an accommodation space for accommodating the unit head is formed, the unit head is an accommodation space. And a groove formed between the unit head and the housing in a state of being housed and fixed.

  As described above, when there is a recess (groove) on the nozzle forming surface, foreign matter scraped from the nozzle forming surface may enter the recess together with the cleaning liquid during wiping by reciprocating wiping control. When time elapses in this state, depending on the shape of the concave portion, the foreign matter enters the depth of the concave portion due to a capillary phenomenon, and it is difficult to remove the foreign matter from the concave portion. Therefore, as described above, by performing a reciprocating operation so that the wiping member passes over the recess, the foreign matter is scraped out from the recess together with the cleaning liquid before the foreign matter enters the depth of the recess. it can.

1 is a front view schematically illustrating a configuration of a printer to which the present invention is applicable. The schematic diagram which shows an example of a structure of a maintenance type | system | group. The block diagram which shows an example of the electrical structure concerning a maintenance type | system | group. The flowchart which shows the flow of a maintenance. FIG. 3 is a schematic diagram illustrating a state of a print head and a maintenance unit. The flowchart which shows the flow of pressure cleaning. FIG. 3 is a schematic diagram illustrating a state of a print head and a maintenance unit. The schematic diagram which shows the detail of a nozzle formation surface. The schematic diagram for demonstrating adjustment of the contact force to the nozzle formation surface by a wiper.

  Hereinafter, a configuration of a printer to which the invention can be applied will be described with reference to the drawings. FIG. 1 is a front view schematically showing the configuration of a printer to which the present invention can be applied. In the following drawings, a three-dimensional coordinate system corresponding to the left-right direction X, the front-rear direction Y, and the vertical direction Z of the printer 1 is adopted as necessary in order to clarify the arrangement relationship of each part of the printer 1. ing.

  As shown in FIG. 1, in the printer 1, the feeding unit 2, the process unit 3, and the winding unit 4 are arranged in the left-right direction. The feeding unit 2 and the winding unit 4 have a feeding shaft 20 and a winding shaft 40, respectively. Then, both ends of the sheet S (web) are wound around the feeding unit 2 and the winding unit 4 in a roll shape, and are stretched between them. The sheet S is transported from the feeding shaft 20 to the process unit 3 along the transport path Pc stretched in this manner, subjected to image recording processing by the printing unit 6U, and then transported to the take-up shaft 40. The type of the sheet S is roughly classified into a paper type and a film type. Specific examples include high-quality paper, cast paper, art paper, coated paper, and the like for paper, and synthetic paper, PET (Polyethylene terephthalate), PP (polypropylene), and the like for film. In the following description, of both surfaces of the sheet S, the surface on which an image is recorded is referred to as the front surface, and the opposite surface is referred to as the back surface.

  The feeding unit 2 includes a feeding shaft 20 around which the end of the sheet S is wound, and a driven roller 21 around which the sheet S drawn from the feeding shaft 20 is wound. The feeding shaft 20 supports the end of the sheet S by winding the end thereof with the surface of the sheet S facing outward. Then, when the feeding shaft 20 rotates clockwise in FIG. 1, the sheet S wound around the feeding shaft 20 is fed to the process unit 3 via the driven roller 21.

  In the process unit 3, an image is recorded on the sheet S using the printing unit 6U while the sheet S fed from the feeding unit 2 is supported by the platen drum 30. That is, the printing unit 6 </ b> U has a plurality of print heads 6 a to 6 e arranged along the surface of the platen drum 30, and the print heads 6 a to 6 e eject ink onto the sheet S supported on the surface of the platen drum 30. As a result, an image is recorded on the sheet S. In the process unit 3, a front drive roller 31 and a rear drive roller 32 are provided on both sides of the platen drum 30, and the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 is supported by the platen drum 30. Received image printing.

  The front drive roller 31 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the sheet S fed from the feeding unit 2 from the back side. The front drive roller 31 rotates in the clockwise direction in FIG. 1 to convey the sheet S fed from the feeding unit 2 to the platen drum 30 via the driven roller 33. A nip roller 31n is provided for the front drive roller 31. The nip roller 31 n is in contact with the surface of the sheet S while being urged toward the front drive roller 31, and sandwiches the sheet S between the front drive roller 31. Thereby, the frictional force between the front drive roller 31 and the sheet S is ensured, and the sheet S can be reliably conveyed by the front drive roller 31.

  The platen drum 30 is a cylindrical drum that is rotatably supported by a support mechanism (not shown), and winds the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 from the back side. The platen drum 30 supports the sheet S from the back side while receiving the frictional force between the plate S and rotating in the conveyance direction Ds of the sheet S. Further, the process unit 3 is provided with driven rollers 33 and 34 for folding the sheet S on both sides of the winding part around the platen drum 30. Among these, the driven roller 33 wraps the surface of the sheet S between the front driving roller 31 and the platen drum 30 and folds the sheet S. On the other hand, the driven roller 34 wraps the surface of the sheet S between the platen drum 30 and the rear drive roller 32 and folds the sheet S. Thus, by folding the sheet S on the upstream and downstream sides in the transport direction Ds with respect to the platen drum 30, a long winding portion of the sheet S around the platen drum 30 can be secured.

  The rear drive roller 32 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the sheet S conveyed from the platen drum 30 via the driven roller 34 from the back surface side. Then, the rear drive roller 32 conveys the sheet S to the winding unit 4 by rotating clockwise in FIG. A nip roller 32n is provided for the rear drive roller 32. The nip roller 32 n is in contact with the surface of the sheet S while being urged toward the rear drive roller 32, and sandwiches the sheet S between the rear drive roller 32. Accordingly, a frictional force between the rear drive roller 32 and the sheet S is ensured, and the sheet S can be reliably conveyed by the rear drive roller 32.

  Thus, the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 is supported on the outer peripheral surface of the platen drum 30. In the process unit 3, in order to record a color image on the surface of the sheet S supported by the platen drum 30, a plurality of print heads 6a to 6d corresponding to different colors are provided. Specifically, four print heads 6a to 6d corresponding to yellow, cyan, magenta, and black are arranged along the transport direction Ds in this color order.

  The print heads 6a to 6d have the same configuration and face the surface of the sheet S supported by the platen drum 30 with a slight clearance. Then, ink of a corresponding color is ejected from a nozzle that opens toward the surface of the platen drum 30 by an inkjet method. As a result, ink is ejected onto the sheet S conveyed along the conveyance direction Ds, and a color image is formed on the surface of the sheet S.

  Here, as the ink (recording liquid), UV (ultraviolet) ink (photo-curable ink) that is cured by irradiating ultraviolet rays (light) is used. Therefore, UV lamps 37a and 37b are provided to cure the ink and fix it on the sheet S. The ink curing is performed in two stages, temporary curing and main curing. A UV lamp 37a for temporary curing is disposed between the print heads 6a to 6d. That is, the UV lamp 37a irradiates weak ultraviolet rays to cure (temporarily cure) the ink to such an extent that the shape of the ink does not collapse, and does not completely cure the ink. On the other hand, a UV lamp 37b for main curing is provided on the downstream side in the transport direction Ds with respect to the print heads 6a to 6d. That is, the UV lamp 37b irradiates ultraviolet rays stronger than the UV lamp 37a, thereby completely curing (main curing) the ink. By executing the temporary curing and the main curing in this way, the color image formed by the print heads 6a to 6d can be fixed on the surface of the sheet S.

  Further, the print head 6e is disposed opposite to the surface of the platen drum 30 on the downstream side in the transport direction Ds with respect to the UV lamp 37b. The print head 6e has the same configuration as the print heads 6a to 6d, and ejects transparent UV ink onto the surface of the sheet S by an inkjet method. That is, the print head 6e discharges the transparent ink by the inkjet method while facing the surface of the sheet S supported by the platen drum 30 with a slight clearance. As a result, the transparent ink is further ejected from the color images formed by the print heads 6a to 6d for the four colors.

  A UV lamp 38 is provided on the downstream side in the transport direction Ds with respect to the print head 6e. The UV lamp 38 irradiates strong ultraviolet rays to completely cure (main cure) the transparent ink discharged from the print head 6e. Thereby, the transparent ink can be fixed on the surface of the sheet S.

  As described above, in the process unit 3, ink discharge and curing are appropriately performed on the sheet S supported by the platen drum 30 to form a color image coated with the transparent ink. Then, the sheet S on which the color image is formed is conveyed to the winding unit 4 by the rear drive roller 32.

  The winding unit 4 includes a winding shaft 40 that winds the end of the sheet S, and a driven roller 41 that winds the sheet S conveyed to the winding shaft 40. The winding shaft 40 winds and supports the end of the sheet S with the surface of the sheet S facing outward. And the sheet | seat S is wound around the winding shaft 40 via the driven roller 41 by the winding shaft 40 rotating clockwise of FIG.

  Incidentally, the printer 1 is provided with a maintenance system for performing maintenance on the print heads 6a to 6e. FIG. 2 is a schematic diagram showing an example of the configuration of the maintenance system. Since the print heads 6a to 6e have the same configuration, one of the print heads 6a to 6e is represented as the print head 6 without distinguishing the print heads 6a to 6e. The maintenance performed on the print head 6 will be described. In the following, for convenience of explanation, a case where the nozzle forming surface 60 is substantially horizontal as shown in FIG. 2 will be described.

  One maintenance unit 7 </ b> U provided in the maintenance system is arranged for each print head 6, and performs maintenance such as wiping and capping on the print head 6. The maintenance unit 7U is provided adjacent to the platen drum 30 in the Y direction. On the other hand, the print head 6 is movable in the Y direction between a printing position above the platen drum 30 and a maintenance position above the maintenance unit 7U by a head driving mechanism 69. Furthermore, the print head 6 can be set at the maintenance position so that it can take a cleaning position close to the maintenance unit 7U or a retracted position away from the maintenance unit 7U. It can move freely to Dh. At the time of maintenance, the print head 6 appropriately moves in the exit / retreat direction Dh according to the maintenance process.

  The print head 6 includes a nozzle 61 that opens to the nozzle forming surface 60, a reservoir 62 that temporarily stores ink, and a cavity 63 that communicates the nozzle 61 and the reservoir 62, and the reservoir 62 passes through the cavity 63. Then, ink is supplied to the nozzle 61. Then, ink is ejected from the nozzle 61 by the cavity 63 applying pressure to the ink in accordance with an operation command from the control unit 100 (FIG. 3). Further, an ink circulation mechanism 80 is provided for the print head 6, and the ink circulation mechanism 80 allows the speed of ink to circulate between a tank (not shown) for storing ink and the reservoir 62 of the print head 6. Pressure etc. are adjusted.

  The maintenance unit 7U includes a wiper 711, a cap 712, and a moving body 71 having a support member 713 that supports these so as to move together, and a wiper driving mechanism 72 that moves the moving body 71 in the wiping direction Dw along the nozzle forming surface 60. And a cleaning liquid supply pipe 73 for injecting the cleaning liquid from the injection port 73a, and a housing 74. Each of these members has a length in the Y direction that is about the same as or longer than that of the print head 6, and can perform maintenance on the entire nozzle forming surface 60. Wiping is performed by the wiper 711 moving in the wiping direction Dw with the wiping surfaces 711 a and 711 b in contact with the nozzle forming surface 60. Further, capping is performed by the cap 712 closely contacting the nozzle forming surface 60 so as to cover all the nozzles 61.

  The cleaning liquid supply pipe 73 has a plurality of ejection ports 73a that open toward the print head 6 in the Y direction. When the print head 6 is in a cleaning position close to the maintenance unit 7U, the print head 6 The cleaning liquid can be sprayed onto the supply surface 64 that is the side surface on the cleaning liquid supply pipe 73 side. Here, as the cleaning liquid used for wiping, a liquid suitable for the cleaning action can be used as appropriate. However, when UV ink is used as in this embodiment, it is preferable to use a solvent that can dissolve the cured UV ink. . Examples of such a solvent include EDGAC (Ethyl Di Glycol Acetate) and transparent UV ink. Moreover, you may use what added surfactant and the polymerization inhibitor to these solvents as a washing | cleaning liquid. The supply of the cleaning liquid by the cleaning liquid supply pipe 73 is switched by the cleaning liquid supply switching unit 79.

  The casing 74 mainly includes a bottom surface portion 74a substantially parallel to the wiping direction Dw, a side wall portion 74b erected from one end in the wiping direction Dw of the bottom surface portion 74a, and an upper end of the side wall portion 74b along the wiping direction Dw. And has a flange portion 74c extending on the same side as the bottom surface portion 74a. The bottom surface portion 74a is provided over a range slightly wider than the range in which the moving body 71 can move in the wiping direction Dw, and receives waste liquid including ink, cleaning liquid, and the like generated during maintenance. The waste liquid received by the bottom surface portion 74a is discharged from the maintenance unit 7U through the discharge port 74d formed in the bottom surface portion 74a. The flange 74 c has a dimension in the wiping direction Dw larger than that of the moving body 71. During the printing operation, the moving body 71 is in a standby position below the flange portion 74c and is kept covered by the flange portion 74c. By doing so, the collar portion 74c blocks the light (ultraviolet rays) emitted from the UV lamps 37a, 37b, and 38 and suppresses the UV ink attached to the wiper 711 and the cap 712 from being cured.

  FIG. 3 is a block diagram illustrating an example of an electrical configuration according to the maintenance system. The operation of the maintenance system configured as described above is controlled by the control unit 100 provided in the printer 1. For example, the control unit 100 controls the head driving mechanism 69 so that the print head 6 is appropriately disposed at each position such as a cleaning position or a retracted position. Further, the control unit 100 controls the wiper driving mechanism 72 to drive the moving body 71, and the wiper 711 and the cap 712 perform operations according to the maintenance process. In addition, the control unit 100 controls the cleaning liquid supply switching unit 79 so that the cleaning liquid is switched from the injection port 73a of the cleaning liquid supply pipe 73 to a state where the cleaning liquid is not sprayed. In addition, the control unit 100 controls the ink circulation mechanism 80 to adjust the circulation speed, pressure, and the like of the ink supplied to the print head 6.

  Next, the maintenance flow for the print head 6 using the maintenance unit 7U will be described. FIG. 4 is a flowchart showing a maintenance flow, and FIG. 5 is a schematic diagram showing states of the print head and the maintenance unit. In maintenance by the maintenance unit 7U, the cleaning liquid is sprayed onto the supply surface 64, which is the side surface of the print head 6, and then the wiper 711 is reciprocated a plurality of times in the wiping direction Dw to perform pressure cleaning. In the following description, the end position on the supplied surface 64 side in the reciprocating operation of the wiper 711 is indicated as a starting point P1, and the opposite end position is indicated as an end point P2.

  Here, as shown in FIG. 5a, maintenance is performed in a state where the print head 6 is in the retracted position away from the maintenance unit 7U, and the wiper 711 (moving body 71) is in the standby position below the flange 74c. Shall be started. When the maintenance is started, first, the number N of reciprocating operations of the wiper 711 is set to 0 (step S1). Then, according to the operation command from the control unit 100, the wiper drive mechanism 72 moves the wiper 711 to the starting point P1 (step S2), and the head drive mechanism 69 moves the print head 6 to the cleaning position close to the maintenance unit 7U. Move (step S3). As a result, as shown in FIG. 5b, the wiper 711 and the supplied surface 64 are partially in a state in which the tip of the wiper 711 faces the supplied surface 64 of the print head 6, in other words, in the retracting direction Dh. Duplicate state. In this state, the wiper 711 moves in the wiping direction Dw, so that the wiper 711 wipes the nozzle forming surface 60.

  Subsequently, the control unit 100 issues an operation command to supply the cleaning liquid to the cleaning liquid supply switching unit 79, whereby the cleaning liquid is ejected from the ejection port 73 a of the cleaning liquid supply pipe 73 toward the supply surface 64 of the print head 6. (Step S4). The cleaning liquid ejected from the ejection port 73 a passes above the wiper 711 and lands on the supplied surface 64 without landing on the wiper 711. As shown in FIG. 5c, when the cleaning liquid CL is sprayed onto the supplied surface 64, the cleaning liquid CL adhering to the supplied surface 64 flows downward along the supplied surface 64, and the supplied surface 64 and the nozzle It collects in the corner | angular part 66 between the formation surfaces 60. FIG.

  When sufficient cleaning liquid is supplied, the spraying of the cleaning liquid is stopped, and the wiper 711 is moved from the starting point P1 to the ending point P2 to perform wiping (step S5). In this process, as shown in FIG. 5d, the wiping surface 711a of the wiper 711 comes into contact with the corner portion 66, and the cleaning liquid CL accumulated in the corner portion 66 is held by the wiper 711. Then, wiping is performed while spreading the cleaning liquid held by the wiper 711 on the nozzle forming surface 60.

  FIG. 5e shows a state where the wiper 711 is moved to the end point P2. The end point P2 of the reciprocating operation of the wiper 711 is located below the print head 6. Thus, the position of the end point P2 is set below the print head 6 for the following reason. When the wiper 711 is moved further to the right than the side surface 65 opposite to the supply surface 64, the next time the wiper 711 moves toward the starting point P1, the wiping surface 711b (FIG. 2) of the wiper 711 is the side surface. 65 abuts. Since the cleaning liquid is not sprayed on the side surface 65, foreign matter such as cured UV ink remains, and when the wiper 711 comes into contact with the side surface 65, these foreign matter may adhere to the wiper 711. Thus, by setting the end point P2 below the print head 6, contact between the wiping surface 711b and the side surface 65 is avoided, and good wiping is realized.

  Subsequently, the print head 6 is once moved to the retracted position and then returned to the cleaning position again (step S6). Thus, when the print head 6 once moves to the retracted position, the state in which the wiper 711 positioned at the end point P2 is curved leftward is eliminated (f diagram in FIG. 5). When the print head 6 is returned to the cleaning position, as shown in FIG. 5g, if the wiper 711 is bent rightward by the nozzle forming surface 60, the wiper 711 moves from the end point P2 to the start point P1. Is done smoothly. For example, if the wiper 711 is attached so that the wiper 711 is slightly inclined to the right in the state of FIG. 5f, the wiper 711 is reliably moved to the right when the print head 6 is returned to the cleaning position. Can be curved.

  In the state where the wiper 711 is curved rightward, the wiper 711 is moved from the end point P2 to the start point P1, and wiping is performed (step S7). Thus, when the wiper 711 returns to the starting point P1, the reciprocating operation of the wiper 711 is completed once (FIG. 5 h). Subsequently, the print head 6 is once moved to the retracted position and then moved again to the cleaning position (step S8). Then, the control unit 100 increments the number N of reciprocating motions of the wiper 711 (step S9), and then determines whether or not the reciprocating motion has been performed 5 times (step S10). If it is less than 5 times, it returns to step S5 and repeats the reciprocating operation. If it has reached 5 times, the pressure cleaning is continued (step S11). When the pressure cleaning is completed, the print head 6 is finally moved to the retracted position (step S12), the wiper 711 is moved to the standby position (step S13), and the state shown in FIG.

  Next, pressure cleaning will be described. FIG. 6 is a flowchart showing the flow of pressure cleaning, and FIG. 7 is a schematic diagram showing the state of the print head and the maintenance unit. In the pressure cleaning, first, the ink circulation mechanism 80 (FIG. 2) accelerates the ink circulation speed to a pressure speed faster than the normal speed during the printing operation in accordance with an operation signal from the control unit 100 (step S101). ).

  Subsequently, as shown in FIG. 7a, the moving body 71 of the maintenance unit 7U is moved below the print head 6, and then the print head 6 is moved to a capping position further below the cleaning position. Then, the nozzle forming surface 60 is pressed against the cap 712 to cap all the nozzles 61 (step S102). The wiper 711 normally maintains a state of protruding upward from the support member 713 by a biasing member (not shown). However, when the print head 6 is moved to the capping position, the print head 6 serves as the biasing member. Resist the wiper 711 downward. Therefore, the wiper 711 does not hinder capping.

  When the capping is completed, the ink is pressurized by the ink circulation mechanism 80 (step S103). When the ink is sufficiently pressurized, the capping is canceled by moving the print head 6 to the retracted position (step S104). By releasing the capping, the pressurized ink IK is ejected from the nozzle 61 as shown in FIG. At this time, along with the ink IK discharged from the nozzle 61, the cleaning liquid, bubbles, and the like in the nozzle 61 are discharged from the nozzle 61. As described above, when the capping is canceled and the ink is ejected from the nozzle 61, the pressurization of the ink is stopped (step S105).

  In the pressure cleaning, wiping is further performed on the nozzle forming surface 60 (step S106). Various forms of wiping can be employed here. For example, the wiper 711 may be moved only once from the start point P1 to the end point P2 without supplying the cleaning liquid. As a result, ink ejected from the nozzle 61 and adhered to the nozzle forming surface 60 is wiped off. Subsequently, after the ink circulation speed is reduced to the normal speed (step S107), flushing is performed to eject ink from all the nozzles 61, and the ink is filled into the nozzles 61 with an appropriate meniscus formed. (Step S108). When the above pressure cleaning is completed, the process returns to the flowchart of FIG. 4 and steps S12 and S13 are executed to complete the maintenance.

  As described above, in this embodiment, the reciprocating wiping is performed in which the wiper 711 holding the supplied cleaning liquid is reciprocated in the wiping direction Dw between the start point P1 and the end point P2. In this way, by causing the wiper 711 to reciprocate, the cleaning liquid spreads over the nozzle forming surface 60 uniformly and can be sufficiently spread. As a result, effective cleaning using the cleaning liquid becomes possible.

  In reciprocating wiping, the reciprocating operation of the wiper 711 is executed a plurality of times (five times). As described above, the wiper 711 reciprocates a plurality of times, so that it is possible to more suitably spread the cleaning liquid. At the same time, since the force by the wiper 711 is applied a plurality of times from both directions of the wiping direction Dw to foreign matter such as cured ink adhering to the nozzle forming surface 60, suitable scraping can be realized.

  Furthermore, by performing pressure cleaning after performing reciprocal wiping, the cleaning liquid that has entered the nozzle 61 during reciprocal wiping can be discharged from the nozzle 61 along with ink ejection. Further, by performing wiping without using the cleaning liquid in the pressure cleaning, it is possible to clean the nozzle forming surface 60 that is soiled by the ejection of ink while avoiding the cleaning liquid from entering the nozzle 61.

  Here, a detailed configuration of the print head 6 in this embodiment and a configuration suitable for wiping the nozzle forming surface 60 of the print head 6 will be described. FIG. 8 is a schematic diagram showing details of the nozzle forming surface. The print head 6 includes a housing 6 </ b> A in which a plurality of accommodation spaces 67 that are open on the nozzle forming surface 60 are formed, and unit heads 6 </ b> B that are accommodated one by one in each accommodation space 67.

  A plurality of storage spaces 67 are provided in the Y direction to form a row, and two rows are provided while shifting the position in the Y direction in the wiping direction Dw orthogonal to the Y direction, so that the storage spaces 67 are staggered. ing. In the unit head 6B, a plurality of nozzles 61 are provided in a direction (Y direction) perpendicular to the wiping direction Dw to form a nozzle row, and a plurality of nozzle rows are arranged in the wiping direction Dw. Two-dimensional arrangement. In a state where one unit head 6B is arranged in each housing space 67, an adhesive is filled between the side surface of the unit head 6B and the inner wall surface of the housing space 67, so that each unit head 6B has a housing 6A. It is fixed against. At this time, a groove 68 may be formed on the nozzle forming surface 60 between the housing 6A and the unit head 6B due to shrinkage or filling state of the adhesive.

  When the foreign matter scraped off from the nozzle forming surface 60 enters the narrow space such as the groove portion 68 together with the cleaning liquid, the foreign matter enters the depth of the groove portion 68 due to capillary action, and the foreign matter is removed. The problem that it becomes difficult to remove from the groove part 68 arises. Therefore, in this embodiment, the length of the wiper 711 in the Y direction is longer than the length of the nozzle forming surface 60 in the Y direction, so that the wiper 711 is brought into contact with the entire nozzle forming surface 60 during reciprocal wiping. By doing so, before the wiper 711 passes over each groove 68 during the reciprocating wiping and the foreign matter enters the depth of the groove 68, the foreign matter is scraped out from the groove 68 together with the cleaning liquid, so that suitable cleaning can be performed.

  The above-described problem is not limited to the groove 68 between the housing 6A and the unit head 6B, and may be caused by a minute recess existing in the nozzle forming surface 60. When the wiper 711 passes over the recess during reciprocating wiping, suitable cleaning can be performed as described above.

  By the way, although explanation is omitted in the above, more suitable wiping can be executed by appropriately adjusting the moving speed of the wiper 711 during wiping and the contact force with which the wiper 711 contacts the nozzle forming surface 60. Hereinafter, this point will be described in detail.

  In this embodiment, the reciprocating operation of the wiper 711 in the reciprocating wiping is performed five times. For example, after executing the low speed control in which the speed of the first reciprocating operation is the first speed, the remaining four times are performed. It is possible to execute high-speed control in which the reciprocating speed is set to a second speed that is faster than the first speed. Specifically, when steps S5 and S7 are executed when N = 0 in the flowchart of FIG. 4, the control unit 100 issues an operation command for low speed control to the wiper drive mechanism 72, so that the wiper 711 moves at a relatively low first speed to perform wiping. On the other hand, when steps S5 and S7 are executed when N = 1 to 4, the control unit 100 issues a high-speed control operation command to the wiper drive mechanism 72, so that the wiper 711 has a relatively high speed. Wipe by moving at 2 speeds.

  As described above, the low-speed control in which the speed of the wiper 711 is relatively low is executed at the initial stage of the reciprocating wiping, so that the cleaning liquid can be firmly spread on the nozzle forming surface 60. In addition, since the high speed control is performed after the low speed control is performed, it is possible to suppress an increase in the time required for reciprocal wiping as a whole. The same effect can be obtained by executing the low speed control only when the wiper 711 moves from the starting point P1 to the end point P2 for the first time, or by continuously executing the low speed control in the second and subsequent reciprocating operations. Further, the moving speed of the wiper 711 does not necessarily need to be changed in two stages, and may be three or more stages, or the speed can be gradually changed.

  In this embodiment, the contact force with which the wiper 711 contacts the nozzle forming surface 60 during reciprocating wiping is set larger than the contact force during wiping in pressure cleaning. FIG. 9 is a schematic diagram for explaining the adjustment of the contact force on the nozzle forming surface by the wiper. More specifically, FIG. 9a shows the state during reciprocating wiping, and FIG. 9b shows the state during wiping in pressure cleaning. Indicates the state.

  When step S3 in FIG. 4 is completed and the wiper 711 is located at the starting point P1 and the print head 6 is in the cleaning position, as shown in FIG. And the wiper 711 are overlapped by a distance L1 in the exit / retreat direction Dh. In this state, the wiper 711 moves in the wiping direction Dw, so that the wiper 711 comes into contact with the nozzle forming surface 60 in a curved state and wiping is performed. That is, at the time of reciprocal wiping, the tip of the wiper 711 is curved according to the distance L1, and the wiper 711 is applied to the nozzle forming surface 60 by the contact force according to the restoring force (elastic force) that tries to restore the curved state to the upright state. It is in contact.

  On the other hand, when wiping in step S106 in FIG. 6 is started in the pressure cleaning, the head drive mechanism 69 causes the print head 6 to move in response to an operation command from the control unit 100, as shown in FIG. It arrange | positions in the position above a washing | cleaning position (refer a figure of FIG. 9). As a result, the distance that the surface to be supplied 64 of the print head 6 and the wiper 711 overlap in the exit / retreat direction Dh is a distance L2 that is shorter than the distance L1. In this state, when the wiper 711 moves in the wiping direction Dw and the wiping is performed, the degree to which the tip of the wiper 711 is curved becomes smaller than that during the reciprocating wiping, and as a result, according to the restoring force of the wiper 711 The contact force to the nozzle forming surface 60 is smaller than that during reciprocal wiping. In other words, the contact force at the time of reciprocating wiping is larger than the contact force at the time of pressure cleaning wiping.

  In this way, by making the contact force with which the wiper 711 contacts the nozzle forming surface 60 during reciprocating wiping larger than the contact force during wiping during pressure cleaning, the cleaning liquid is applied to the nozzle forming surface 60 by the wiper 711 during reciprocating wiping. It is possible to spread it while pressing firmly. On the other hand, at the time of wiping in pressure cleaning, since uncured ink adhering to the nozzle formation surface 60 is simply wiped off by ink ejection from the nozzle 61 just before, the nozzle formation surface 60 can be sufficiently removed even if the contact force by the wiper 711 is small. Can be washed.

  In addition, instead of or in addition to the change of the position of the print head 6 in the exit / retreat direction Dh, by changing the position of the wiper 711 in the exit / retreat direction Dh, It is also possible to adjust the contact force by changing the position. Further, the timing of moving the print head 6 or the wiper 711 in the exit / retreat direction Dh can be changed as appropriate. For example, after the wiper 711 comes into contact with the nozzle forming surface 60, the position of the print head 6 or the wiper 711 in the retracting direction Dh can be changed to adjust the contact force.

  As described above, in this embodiment, the printer 1 corresponds to the “liquid discharge device” of the present invention, the ink corresponds to the “liquid” of the present invention, and the print head 6 corresponds to the “discharge head” of the present invention. The wiper 711 corresponds to the “wiping member” of the present invention, the cleaning liquid supply pipe 73 corresponds to the “cleaning liquid supply unit” of the present invention, and the direction from the start point P1 to the end point P2 is the “first direction” of the present invention. The direction from the end point P2 to the starting point P1 corresponds to the “second direction” of the present invention, and steps S5 to S10 executed by the control unit 100 during reciprocating wiping correspond to “reciprocating wiping control” of the present invention. Steps S101 to S108 executed by the control unit 100 during pressure cleaning correspond to “cleaning control” of the present invention.

  In the above description, for the sake of convenience, the content of maintenance has been described for the case where the nozzle formation surface 60 is substantially horizontal. However, even when the nozzle formation surface 60 is inclined from the horizontal plane, the wiping direction Dw is directed to the nozzle formation surface 60. It goes without saying that the maintenance described so far can be performed by arranging the maintenance unit 7U along the same line.

  The present invention is not limited to the above-described embodiment, and the elements of the above-described embodiment can be appropriately combined or variously modified without departing from the spirit of the present invention. For example, in the above embodiment, the cleaning liquid is supplied to the supply surface 64 that is the side surface of the print head 6, but the cleaning liquid may be directly supplied to the wiper 711. In that case, the cleaning liquid may be supplied near the upper end of the wiper 711 so that the cleaning liquid flows on the wiping surface 711 a of the wiper 711 and is held by the wiper 711.

  In the above embodiment, wiping is performed by moving the wiper 711 in the wiping direction Dw. However, wiping may be performed by moving the nozzle forming surface 60, that is, the print head 6, in the wiping direction Dw. . It is also possible to perform wiping by moving both the wiper 711 and the print head 6 in the wiping direction Dw.

  In the above embodiment, the low speed control and the high speed control of the wiper 711 are performed during the reciprocal wiping. However, such control for changing the moving speed of the wiper 711 is not an essential requirement for the present invention, and the moving speed of the wiper 711 during reciprocating wiping may be kept constant.

  In the above-described embodiment, the contact force with which the wiper 711 contacts the nozzle forming surface 60 during reciprocating wiping is greater than the contact force during wiping in pressure cleaning. However, changing the contact force in this way is not an essential requirement of the present invention, and the relative position of the print head 6 and the wiper 711 in the retracting direction Dh is constant during reciprocating wiping and wiping in pressure cleaning. May be maintained.

  Further, the flow shown in FIGS. 4 and 6 in the above embodiment can be appropriately changed. For example, the number of reciprocating operations of the wiper 711 may be changed, or the operation performed by pressure cleaning may be changed. Furthermore, pressure cleaning can be omitted.

  The specific configuration of the printer 1 can be changed as appropriate, and the arrangement and number of the print heads 6 and the maintenance units 7U may be changed as appropriate, and the shape of the platen drum 30 may be changed as appropriate.

  Further, the type of ink ejected from the nozzle 61 is not limited to the UV ink described above. Furthermore, the present invention can also be applied to a liquid ejecting apparatus that ejects liquid other than ink.

  DESCRIPTION OF SYMBOLS 1 ... Printer (liquid discharge apparatus), 6 ... Print head (discharge head), 6A ... Housing, 6B ... Unit head, 60 ... Nozzle formation surface, 61 ... Nozzle, 67 ... Accommodating space, 68 ... Groove part (concave part), 7U ... maintenance unit, 711 ... wiper (wiping member), 73 ... cleaning liquid supply pipe (cleaning liquid supply part), 100 ... control part.

Claims (6)

An ejection head having a nozzle forming surface on which nozzles for ejecting liquid are formed;
A wiping member for wiping the nozzle forming surface by moving relative to the discharge head;
A cleaning liquid supply unit for supplying a cleaning liquid for wiping;
A liquid reservoir for storing the liquid;
A circulation mechanism that circulates the liquid between the liquid reservoir and the ejection head ,
After the wiping member supplied the previous SL washings executes the first wiping for wiping the nozzle formation face at a first relative moving speed in the higher than first relative moving speed second relative moving speed The second wiping for wiping the nozzle forming surface is performed, and then the pressurized mechanism discharges the liquid from the nozzle by pressurizing the liquid in the discharge head by circulating the liquid. A liquid ejecting apparatus that is executed. The ejection head ejects the liquid onto a medium;
The said circulation mechanism performs said pressurization discharge | emission by circulating with the circulation speed faster than the circulation speed when the said discharge head discharges the said liquid with respect to the said medium. Liquid ejection device. 3. The liquid ejection apparatus according to claim 1 , wherein the wiping member performs the wiping in a state where the cleaning liquid is not supplied following the pressure discharge. 4. 4. The liquid ejection apparatus according to claim 1, wherein the second wiping is performed in a direction opposite to the relative movement direction of the first wiping . 5. 5. The liquid ejection apparatus according to claim 1, wherein the wiping is further performed a plurality of times between the first wiping and the second wiping . An ejection head having a nozzle forming surface in which the nozzles are formed for ejecting liquid, a wiping member for wiping the nozzle formation face by the moving ejection head relative, and the cleaning liquid supply unit for supplying a cleaning liquid to be subjected to the wiping A cleaning method for the discharge head in a liquid discharge apparatus comprising: a liquid storage portion for storing the liquid; and a circulation mechanism for circulating the liquid between the liquid storage portion and the discharge head ,
A cleaning liquid supply step of supplying the cleaning liquid from the cleaning liquid supply unit to the wiping member;
A first wiping step in which the wiping member supplied with the cleaning liquid wipes the nozzle forming surface at a first relative movement speed;
After the first wiping step, a second wiping step of wiping the nozzle forming surface at a second relative movement speed faster than the first relative movement speed;
After the second wiping step, pressurizing and discharging the liquid from the nozzle by pressurizing the liquid in the discharge head by circulating the liquid by the circulation mechanism; and
A method for cleaning an ejection head, comprising:

Images