JPWO2016042835A1 - Droplet discharge device and nozzle surface cleaning method - Google Patents

Abstract

Even when using a wiping member with different absorption time for absorbing liquid per unit amount, the purpose is to suppress discharge failure where liquid droplets are not discharged from the nozzle after wiping off the liquid adhering to the nozzle surface To do. The control unit increases the first moving speed for relatively moving the wiping member and the droplet discharge head as the absorption time for the wiping member to absorb the liquid per unit amount becomes shorter, and the wiping member Increase the second movement speed to move.

Description

  The present invention relates to a droplet discharge device that forms an image on a recording medium, and a nozzle surface cleaning method that cleans a nozzle surface.

  Patent Document 1 discloses a method of collecting ink by soaking it into a cleaning paper (wiping member) as a method of collecting non-volatile ink (liquid) adhering to the nozzle surface of a print head (droplet discharge head). Have been described.

JP 2006-7777 A

  In the conventional configuration, in a state where the wiping member is in contact with a part of the nozzle surface of the liquid droplet ejection head, the liquid adhered to the nozzle surface is wiped by moving the liquid droplet ejection head. The moving speed of the droplet discharge head is set according to the speed at which the liquid is absorbed by the wiping member.

  Here, when wiping the liquid from the nozzle surface, using a wiping member with a short absorption time for absorbing the liquid per unit amount, the ink in the nozzle formed on the nozzle surface is pulled out by the wiping member, The reaction may cause bubbles to be drawn into the head from the nozzle. When the bubbles are drawn into the head, droplets may not be ejected from the nozzles and streaks may occur in the output image.

  The problem of the present invention is that even when a wiping member that absorbs liquid per unit amount has a different absorption time is used, after the liquid adhering to the nozzle surface is wiped off, a discharge failure in which liquid droplets are not discharged from the nozzle. It is to suppress.

  A droplet discharge device according to a first embodiment of the present invention includes a droplet discharge head having a nozzle surface on which a nozzle from which droplets are discharged is formed, a part of which is in contact with a part of the nozzle surface, and a nozzle surface A wiping member for wiping off the liquid adhering to the liquid, a first moving mechanism for relatively moving the wiping member and the droplet discharge head, and a second movement for moving the wiping member and changing a portion in contact with the nozzle surface The mechanism and the first moving mechanism are controlled, and the first moving speed for moving the wiping member and the droplet discharge head relative to each other becomes shorter as the absorption time for the wiping member to absorb the liquid per unit amount becomes shorter. And a controller that controls the second moving mechanism and increases the second moving speed for moving the wiping member.

  According to the above configuration, droplets are ejected from the nozzles formed on the nozzle surface of the droplet ejection head. Further, a wiping member that partially contacts a part of the nozzle surface is provided, and the first moving mechanism relatively moves the wiping member and the droplet discharge head so that the wiping member is a nozzle. Wipe off any liquid adhering to the surface. Further, the second moving mechanism moves the wiping member and changes the portion in contact with the nozzle surface.

  Here, the control unit controls the first moving mechanism to relatively move the wiping member and the droplet discharge head as the absorption time for the wiping member to absorb the liquid per unit amount becomes shorter. The first moving speed is increased, and the second moving mechanism is controlled to increase the second moving speed for moving the wiping member.

  Accordingly, the wiping member having a different absorption time for absorbing the liquid per unit amount is different from the case where the second moving speed does not change based on the absorption time for the wiping member to absorb the liquid per unit amount. Even when it is used, it is possible to suppress ejection failure in which liquid droplets are not ejected from the nozzle after the liquid adhering to the nozzle surface is wiped off.

  The liquid droplet ejection apparatus according to the second embodiment of the present invention is the liquid droplet ejection apparatus according to the first embodiment, comprising a derivation member used for deriving the absorption time of the wiping member, and the control unit The first moving mechanism and the second moving mechanism are controlled based on the absorption time derived by controlling the member.

  According to the above configuration, the control unit controls the first movement mechanism and the second movement mechanism based on the absorption time derived by controlling the derivation member.

  Thereby, the operation | work which a user inputs the absorption time of a wiping member can be eliminated.

  The droplet discharge device according to the third embodiment of the present invention is the droplet discharge device according to the second embodiment, wherein the wiping member is detachable from the second moving mechanism, and the control unit is When the taking member is attached to the second moving mechanism, the first moving mechanism and the second moving mechanism are controlled based on the absorption time derived by controlling the lead member.

  According to the above configuration, when the wiping member is attached to the second movement mechanism, the control unit controls the first movement mechanism and the second movement mechanism based on the absorption time derived by controlling the derivation member. Control.

  Thereby, the absorption time of the wiping member can be derived each time the wiping member is replaced.

  The droplet discharge device according to a fourth embodiment of the present invention is the droplet discharge device according to any one of the first to third embodiments, wherein the second moving mechanism conveys the wiping member. It is a transport mechanism.

  According to the said structure, the part which a wiping member and a nozzle surface contact can be changed because a conveyance mechanism conveys a wiping member.

  A nozzle surface cleaning method according to a fifth embodiment of the present invention is a method for cleaning a nozzle surface having a droplet discharge head and on which a nozzle from which droplets are discharged is formed, a part of which is a nozzle surface The process of moving the wiping member that wipes off the liquid adhering to the nozzle surface and the droplet discharge head relative to each other and moving the wiping member to change the portion that contacts the nozzle surface The first moving speed for relatively moving the wiping member and the droplet discharge head is increased as the absorption time for the wiping member to absorb the liquid per unit amount is shorter, and the wiping member is Increase the second movement speed.

  According to the above configuration, the second moving speed is different from the case where the second unit does not change based on the absorption time for the liquid per unit amount to be absorbed by the wiping member. Even when the take-up member is used, it is possible to suppress a discharge failure in which liquid droplets are not discharged from the nozzle after the liquid adhering to the nozzle surface is wiped off.

  According to the present invention, even when a wiping member that absorbs liquid per unit amount has a different absorption time, after the liquid adhering to the nozzle surface is wiped off, a discharge failure that prevents liquid droplets from being discharged from the nozzle is achieved. Can be suppressed.

It is drawing which showed the graph used in order to produce the conversion table with which the control part of the droplet discharge apparatus which concerns on 1st Embodiment of this invention is provided. It is drawing which showed the graph used in order to produce the conversion table with which the control part of the droplet discharge apparatus which concerns on 1st Embodiment of this invention is provided. It is drawing which showed the conversion table with which the control part of the droplet discharge device which concerns on 1st Embodiment of this invention is provided with the table | surface. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the block diagram which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. FIG. 3 is a block diagram illustrating a control target and the like of a control unit of the droplet discharge device according to the first embodiment of the present invention. FIG. 3 is a perspective view illustrating a part of a nozzle surface of the inkjet head of the droplet discharge device according to the first embodiment of the present invention. It is the block diagram which showed the wiping unit of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. It is the perspective view which showed the maintenance mechanism of the droplet discharge apparatus which concerns on 1st Embodiment of this invention. 1 is a schematic configuration diagram illustrating a droplet discharge device according to a first embodiment of the present invention. 17 (A), 17 (B), and 17 (C), the contact portion between the inkjet head and the wiping member of the liquid droplet ejection apparatus according to the comparative example with respect to the liquid droplet ejection apparatus according to the first embodiment of the present invention. It is drawing which showed. It is the block diagram which showed the wiping unit of the droplet discharge apparatus which concerns on 2nd Embodiment of this invention.

<First Embodiment>
An example of a droplet discharge device according to the first embodiment will be described with reference to FIGS. In the drawings, components having the same function are denoted by the same reference numerals, and redundant description is omitted as appropriate.

(Overall configuration of droplet discharge device)
As shown in FIG. 16, the droplet discharge device 10 according to the present embodiment uses a water-based ultraviolet ink (an ultraviolet curable type using an aqueous medium) as a photocurable ink on a sheet recording medium (paper) P. Ink) is used to record an image by an inkjet method. The droplet discharge device 10 includes a paper feeding unit 12 that feeds the recording medium P, a transport unit that transports the recording medium P, a processing liquid applying unit 14, a processing liquid drying processing unit 16, and an ink discharging unit. The image recording unit 18, an ink fixing processing unit 20 as an ink fixing unit including a drying processing unit 21 and a light irradiation unit 22, a control unit for controlling the entire system, and a paper discharging unit for discharging the recording medium P. 24 as a main part.

1. Configuration of Paper Feed Unit The paper feed unit 12 is configured to feed the recording media P loaded on the paper feed tray 30 to the processing liquid application unit 14 one by one. The sheet feeding unit 12 mainly includes a sheet feeding table 30, a soccer device 32, a sheet feeding roll pair 34, a feeder board 36, a front pad 38, and a sheet feeding drum 40.

  The recording medium P is placed on the paper feed table 30 in a bundle state in which a large number of sheets are stacked. The paper feed table 30 is provided so as to be movable up and down by a paper feed table elevating device (not shown). In the paper feed table elevating device, the drive is controlled in conjunction with the increase / decrease of the recording media P stacked on the paper feed platform 30, and the recording medium P positioned at the top of the bundle is always positioned at a constant height. As described above, the sheet feeding table 30 is configured to move up and down.

  In the soccer device 32, the recording media P loaded on the paper feed tray 30 are picked up one by one from the top and fed to the paper feed roll pair 34. The soccer device 32 includes a suction foot 32A provided so as to be movable up and down and swingable. The suction foot 32A holds the upper surface of the recording medium P by suction, and the recording medium P is transported from the paper feed table 30 to the paper feed roll pair 34. At this time, the suction foot 32A sucks and holds the top surface of the front end side of the recording medium P positioned at the top of the bundle to pull up the recording medium P, and the front end of the pulled up recording medium P constitutes the paper feed roll pair 34. It is set as the structure inserted between a pair of roll 34A and roll 34B.

  One of the rolls 34A and 34B is a drive roll (for example, roll 34A) and the other is a driven roll (for example, roll 34B). The drive roll is connected to a motor (not shown) and is driven to rotate by the rotation of the motor. The motor is driven in conjunction with the feeding of the recording medium P. When the recording medium P is fed from the soccer device 32, the driving roll is rotated in accordance with the timing. The recording medium P inserted between the pair of rolls 34 </ b> A and 34 </ b> B is nipped by the rolls 34 </ b> A and 34 </ b> B and sent out in the installation direction of the feeder board 36.

  The feeder board 36 is formed to correspond to the recording medium width and is configured to guide the recording medium P sent out from the paper feed roll pair 34 to the front pad 38. The feeder board 36 is installed to be inclined downward, and the recording medium P placed on the conveying surface of the conveying path of the feeder board 36 is slid along the conveying surface and guided to the front pad 38. .

  On the feeder board 36, a plurality of tape feeders 36A, which transport the recording medium P and have the transport direction as a longitudinal direction, are provided at intervals in the width direction. The tape feeder 36A is formed in an endless shape and is configured to rotate using a motor (not shown) as a drive source. The recording medium P placed on the conveyance surface of the feeder board 36 is conveyed on the feeder board 36 by the tape feeder 36A.

  A retainer 36B and a roller 36C are installed on the feeder board 36. A plurality of retainers 36 </ b> B are arranged in the longitudinal direction along the conveyance surface of the recording medium P (two in the present embodiment). The retainer 36 </ b> B is configured by a leaf spring having a width corresponding to the recording medium width, and is pressed against and brought into contact with the conveyance surface. In the recording medium P conveyed on the feeder board 36 by the tape feeder 36A, the unevenness is corrected by passing through the retainer 36B. The roller 36C is disposed between an upstream retainer 36B and a downstream retainer 36B disposed in the transport direction. The roller 36 </ b> C is pressed against the conveying surface of the recording medium P. The recording medium P conveyed between the retainers 36B is conveyed while the upper surface is pressed by the rollers 36C.

  The front pad 38 is configured to correct the posture of the recording medium P. The front pad 38 is formed in a plate shape, and a plate-like surface is disposed orthogonal to the conveyance direction of the recording medium P. Further, the front pad 38 is connected to a motor (not shown), and is driven to swing by the motor. When the leading edge of the recording medium P conveyed on the feeder board 36 comes into contact with the front pad 38, the conveying posture of the recording medium P is corrected (so-called skew prevention is performed). The front pad 38 is swung in conjunction with the feeding of the recording medium P to the paper feeding drum 40, and the recording medium P whose transport posture is corrected is delivered to the paper feeding drum 40.

  The paper feed drum 40 receives the recording medium P fed from the feeder board 36 via the front pad 38 and conveys it to the processing liquid application unit 14. The paper feed drum 40 is formed in a cylindrical shape, is connected to a motor (not shown), and is configured to rotate by driving from this motor. A gripper 40A is provided on the outer peripheral surface of the paper supply drum 40, and the leading end of the recording medium P is gripped by the gripper 40A. The paper feed drum 40 conveys the recording medium P to the treatment liquid application unit 14 while winding the recording medium P on the peripheral surface by gripping and rotating the tip of the recording medium P with the gripper 40A.

2. Configuration of Processing Liquid Applying Unit The processing liquid applying unit 14 applies a predetermined processing liquid to the surface (image recording surface) of the recording medium P. The treatment liquid application unit 14 mainly applies a treatment liquid application drum 42 that conveys the recording medium P, and a treatment liquid application that applies a predetermined treatment liquid to the image recording surface of the recording medium P that is conveyed by the treatment liquid application drum 42. And a unit 44. The treatment liquid applied to the surface of the recording medium P aggregates the color material (pigment) in the photocurable ink that is ejected (dropped) onto the recording medium P by the image recording unit 18 disposed on the downstream side in the transport direction. It is a flocculant having the function of

  The treatment liquid application drum 42 conveys the recording medium P conveyed from the paper supply drum 40 of the paper supply unit 12 to the treatment liquid drying processing unit 16. The treatment liquid application drum 42 is formed in a cylindrical shape, is connected to a motor (not shown), and is configured to be driven by the rotation of this motor. A gripper 42A is provided on the outer peripheral surface of the treatment liquid application drum 42, and the leading end of the recording medium P is gripped by the gripper 42A. The treatment liquid application drum 42 conveys the recording medium P to the treatment liquid drying processing unit 16 while winding the recording medium P on the peripheral surface by gripping and rotating the tip of the recording medium P with the gripper 42A. . When the treatment liquid application drum 42 rotates once, one recording medium P is conveyed. The processing liquid application drum 42 and the paper feed drum 40 are controlled in rotation by matching the timings of receiving and delivering the recording medium P with each other. In other words, the treatment liquid application drum 42 and the paper feed drum 40 are driven with their peripheral speeds matched, and are driven with the positions of the grippers 40A and 42A matched.

  In the treatment liquid application unit 44, the treatment liquid is applied to the surface of the recording medium P conveyed by the treatment liquid application drum 42 by a roll. The processing liquid application unit 44 mainly pumps up the coating roll 44A for applying the processing liquid to the recording medium P, the processing liquid tank 44B for storing the processing liquid, and the processing liquid stored in the processing liquid tank 44B, The pumping roll 44 </ b> C is supplied to the coating roll 44 </ b> A.

3. Configuration of Processing Liquid Drying Processing Unit In the processing liquid drying processing unit 16, the recording medium P having the processing liquid applied to the surface is dried. The processing liquid drying processing unit 16 mainly performs drying air on the image recording surface of the recording medium P transported by the processing liquid drying processing drum 46 that transports the recording medium P, the paper transport guide 48, and the processing liquid drying processing drum 46. And a processing liquid drying processing unit 50 for spraying and drying.

  The processing liquid drying processing drum 46 is configured to receive the recording medium P from the processing liquid application drum 42 of the processing liquid application unit 14 and to transport the recording medium P to the image recording unit 18. The treatment liquid drying treatment drum 46 is configured by a cylindrical frame, is connected to a motor (not shown), and is driven by the rotation of the motor. A gripper 46A is provided on the outer peripheral surface of the processing liquid drying processing drum 46, and the leading end of the recording medium P is gripped by the gripper 46A. The processing liquid drying processing drum 46 conveys the recording medium P to the image recording unit 18 by gripping and rotating the tip of the recording medium P with the gripper 46A. Note that the processing liquid drying processing drum 46 in the present embodiment is configured such that grippers 42A are disposed at two locations on the outer peripheral surface, and the two recording media P are conveyed by one rotation. The rotation of the processing liquid drying processing drum 46 and the processing liquid applying drum 42 is controlled by matching the timings of receiving and transferring both recording media P. That is, the processing liquid drying processing drum 46 and the processing liquid application drum 42 are driven with their peripheral speeds matched, and are driven with the positions of the grippers 42A and the grippers 46A of each other.

  The paper transport guide 48 is disposed around the outer periphery of the processing liquid drying processing drum 46 along the transport path of the recording medium P. The paper transport guide 48 guides the recording medium P so as not to be detached from the processing liquid drying processing drum 46 (transport path).

  The processing liquid drying processing unit 50 is installed inside the processing liquid drying processing drum 46 and is configured to perform drying processing by blowing dry air toward the surface of the recording medium P conveyed by the processing liquid drying processing drum 46. ing. Thereby, the solvent component in the processing liquid is removed, and an ink aggregation layer is formed on the surface of the recording medium P. In the present embodiment, two processing liquid drying processing units 50 are arranged in the processing liquid drying processing drum, and the drying air is directed toward the surface of the recording medium P conveyed by the processing liquid drying processing drum 46. It is configured to spray.

4). Configuration of Image Recording Unit The image recording unit 18 is a photocurable ink (an example of liquid) of each color of M (magenta), K (black), C (cyan), and Y (yellow) on the image recording surface of the recording medium P. The ink droplet (an example of a droplet) is ejected and a color image is recorded (printed or drawn) on the image forming surface of the recording medium P. The image recording unit 18 mainly presses the image recording drum 52 that conveys the recording medium P and the recording medium P that is conveyed by the image recording drum 52 so that the recording medium P adheres to the peripheral surface of the image recording drum 52. A recording medium pressing roll 54 to be ejected, inkjet heads 56M, 56K, 56C and 56Y for ejecting ink droplets of M, K, C, and Y colors to the recording medium P, and an in-line sensor for reading an image recorded on the recording medium P 58, a mist filter 60 for capturing ink mist, and a drum cooling unit 62. Note that, as described above, photocurable ink is used as the ink ejected from the inkjet heads 56M, 56K, 56C, and 56Y. After the ejection, the photocurable ink is cured and dried by irradiating light (here, ultraviolet rays) by an ink fixing unit described later. In the following description, when there is no need to distinguish magenta (M), black (K), cyan (C), and yellow (Y), the symbols M, K, C, and Y are omitted. To do.

  The image recording drum 52 is configured to receive the recording medium P from the processing liquid drying processing drum 46 of the processing liquid drying processing unit 16 and to transport the recording medium P to the ink fixing processing unit 20. The image recording drum 52 is formed in a cylindrical shape, is connected to a motor (not shown), and is driven by the rotation of this motor. A gripper 52A is provided on the outer peripheral surface of the image recording drum 52, and the leading end of the recording medium P is gripped by the gripper 52A. The image recording drum 52 conveys the recording medium P to the ink fixing processing unit 20 while winding the recording medium P around the peripheral surface by gripping and rotating the tip of the recording medium P with the gripper 52A. In addition, a large number of suction holes (suction holes) (not shown) are provided in a predetermined pattern on the peripheral surface of the image recording drum 52. The recording medium P wound around the peripheral surface of the image recording drum 52 is sucked through the suction hole, so that it can be conveyed while being sucked and held on the peripheral surface of the image recording drum 52. Thereby, the recording medium P can be conveyed with high smoothness.

  Further, the image recording drum 52 in the present embodiment is provided with grippers 52A at two locations on the outer peripheral surface, and can transport two recording media P by one rotation. The rotation of the image recording drum 52 and the processing liquid drying processing drum 46 is controlled by matching the timings of receiving and delivering both recording media P. That is, the image recording drum 52 and the processing liquid drying processing drum 46 are driven with the peripheral speeds matched, and are driven with the positions of the grippers 46A and the grippers 52A matched.

  The recording medium press roll 54 is disposed in the vicinity of the receiving position of the recording medium P of the image recording drum 52 (the position where the recording medium P is received from the processing liquid drying processing drum 46). The recording medium press roll 54 is constituted by a rubber roll, for example, and is installed in press contact with the peripheral surface of the image recording drum 52. The recording medium P transferred from the processing liquid drying processing drum 46 to the image recording drum 52 is nipped by passing through the recording medium pressing roll 54 and is brought into close contact with the peripheral surface of the image recording drum 52.

  The four inkjet heads 56M, 56K, 56C, and 56Y are arranged on the outer peripheral surface of the image recording drum 52 along the conveyance path of the recording medium P at a constant interval. The ink jet heads 56 for each color are constituted by line heads corresponding to the recording medium width, and the nozzle surface 78 (see FIG. 13) is arranged to face the peripheral surface of the image recording drum 52. Each color inkjet head 56 is transported by the image recording drum 52 by ejecting droplets of photocurable ink from a plurality of nozzles 78 </ b> A (see FIG. 13) formed on the nozzle surface 78 toward the image recording drum 52. An image is recorded on the recording medium P to be recorded.

  The inline sensor 58 is installed on the downstream side of the rearmost inkjet head 56K with respect to the conveyance direction of the recording medium P by the image recording drum 52, and reads an image recorded by the inkjet head 56 of each color. Has been. The inline sensor 58 is constituted by a line scanner, for example.

  A contact prevention plate 59 installed in the vicinity of the inline sensor 58 is provided on the downstream side of the inline sensor 58. The contact prevention plate 59 can prevent the recording medium P from coming into contact with the in-line sensor 58 when the recording medium P is lifted or broken due to a conveyance failure or the like.

  The mist filter 60 is disposed between the rearmost inkjet head 56Y and the in-line sensor 58, and sucks air around the image recording drum 52 to capture the ink mist. By capturing the ink mist, the ink mist is prevented from entering the in-line sensor 58, and the occurrence of image reading defects and the like is effectively prevented.

  The drum cooling unit 62 is configured to cool the image recording drum 52 by blowing cool air onto the image recording drum 52. The drum cooling unit 62 is mainly composed of an air conditioner (not shown) and a duct 62 </ b> A that blows cool air supplied from the air conditioner onto the peripheral surface of the image recording drum 52. The duct 62 </ b> A is configured to cool the image recording drum 52 by blowing cool air to the image recording drum 52 in an area other than the conveyance area of the recording medium P. In the present embodiment, since the recording medium P is conveyed along the arcuate outer peripheral surface of the upper half of the image recording drum 52, the duct 62 </ b> A is cooled in the region of the lower half of the image recording drum 52. Is applied to cool the image recording drum 52. Specifically, the air outlets (not shown) of the duct 62 </ b> A are arranged in an arc shape so as to cover substantially the lower half of the image recording drum 52. The details of the maintenance mechanism 80 that performs maintenance operations such as cleaning of the inkjet heads 56 of each color and the nozzle surfaces 78 of the inkjet heads 56 of each color will be described later.

5. Configuration of Ink Fixing Processing Unit The ink fixing processing unit 20 is configured to remove the liquid component remaining on the image recording surface of the recording medium P and to post-process the recording medium P after image recording. The ink fixing processing unit 20 mainly includes a chain gripper 64 that transports a recording medium P on which an image is recorded, a back tension applying mechanism 66 that applies back tension to the recording medium P transported by the chain gripper 64, and a chain gripper. 64, a drying processing unit 21 and a light irradiation unit 22 are provided as ink fixing means for fixing the recording medium P conveyed.

  The chain gripper 64 is used in common in the drying processing unit 21, the light irradiation unit 22, and the paper discharge unit 24, and receives the recording medium P delivered from the image recording unit 18 and conveys it to the paper discharge unit 24. It is said that.

  The chain gripper 64 mainly includes a first sprocket 64A installed close to the image recording drum 52 side, a second sprocket 64B installed on the paper discharge unit 24 side, and the first sprocket 64A and the second sprocket 64B. A chain 64C as an endless conveyance path wound around the chain, a plurality of chain guides (not shown) for guiding the travel of the chain 64C, and a plurality of grippers 64D attached to the chain 64C at a constant interval. It is configured. The first sprocket 64A, the second sprocket 64B, the chain 64C, and the chain guide are configured as a pair on both sides in the conveyance width direction of the recording medium P. The grippers 64D are provided on the pair of chains 64C, respectively. The first sprocket 64A is connected to a motor (not shown) and is driven by the rotation of this motor. The second sprocket 64B is dependently rotatable.

  The back tension applying mechanism 66 is configured to apply a back tension to the recording medium P that is conveyed while its tip is gripped by the chain gripper 64. The back tension applying mechanism 66 is not shown in detail, but mainly includes a guide plate 72 and a plurality of suction fans 72A as suction means for sucking air from a number of suction holes formed in the guide plate 72. It is equipped with. The lower surface of the guide plate 72 is provided with a number of holes for discharging the sucked air. In the recording medium P conveyed by the chain gripper 64, back tension is applied by being sucked by the suction fan 72A through the suction hole of the guide plate 72.

(1) Configuration of Drying Processing Unit The drying processing unit 21 is provided on the upstream side in the transport direction of the chain gripper 64 and inside the chain gripper 64, and is arranged along the transport direction. It has. The drying processing unit 68 is configured to blow dry air (for example, hot air) on the image recording surface of the recording medium P. When the drying air is blown by the drying processing unit 68, the amount of water in the photocurable ink is reduced before the light (ultraviolet ray) is irradiated by the light irradiation unit 22. Thereby, the curability of the photocurable ink is secured by the subsequent light irradiation.

(2) Configuration of Light Irradiation Unit The light irradiation unit 22 is configured to fix an image by irradiating ultraviolet rays (UV) as light on an image recorded using photocurable ink in the present embodiment. ing. The light irradiation unit 22 mainly includes a chain gripper 64 that conveys the recording medium P, a back tension applying mechanism 66 that applies a back tension to the recording medium P and serves as a suction unit, and an irradiation unit that irradiates the recording medium P with light. 74.

  The irradiation unit 74 is provided downstream of the drying processing unit 21 in the conveyance direction of the chain gripper 64 and inside the chain gripper 64, and a plurality of irradiation units 74 are arranged along the conveyance direction. The irradiation unit 74 includes an ultraviolet lamp as a light source (not shown). The back tension applying mechanism 66 mainly includes a guide plate 72 and a plurality of suction fans 72B as suction means for sucking air from a number of suction holes formed in the guide plate 72. The lower surface of the guide plate 72 is provided with a number of holes for discharging the sucked air. In the recording medium P conveyed by the chain gripper 64, back tension is applied by being sucked by the suction fan 72 </ b> B through the suction hole of the guide plate 72.

6). Configuration of Paper Discharge Unit The paper discharge unit 24 is configured to collect the recording medium P that has undergone a series of image recording processes. The paper discharge unit 24 mainly includes a chain gripper 64 that transports the recording medium P on which the photocurable ink is fixed by light irradiation, and a paper discharge tray 76 that stacks and collects the recording medium P. . Although not shown, the paper discharge tray 76 is provided with a sheet pad (front sheet pad, rear sheet pad, lateral sheet pad, etc.) for orderly stacking the recording media P. In addition, a discharge tray lifting device (not shown) is provided on the discharge tray 76 so that the recording medium P can be raised and lowered. In the paper delivery platform lifting / lowering device, the elevation drive is controlled in conjunction with the increase / decrease of the recording media P collected on the paper delivery platform 76, so that the topmost recording media P is always positioned at a certain height. Has been adjusted to.

7). Photocurable ink As the photocurable ink, for example, an aqueous ultraviolet ink that is cured by irradiation with ultraviolet rays as light is used. The aqueous ultraviolet ink preferably contains a pigment, polymer particles, a water-soluble polymerizable compound that is polymerized by active energy rays, and a photopolymerization initiator. In such an aqueous ultraviolet ink, when cured by being irradiated with ultraviolet rays, the image has excellent abrasion resistance and the image has high film strength. Note that the coloring material may include a dye.

(Main part configuration)
Next, a maintenance mechanism 80 that performs maintenance operations such as cleaning of the inkjet heads (an example of a droplet discharge head) 56 of each color and the nozzle surface 78 of the inkjet heads 56 of each color will be described.

  As shown in FIG. 13, the inkjet head 56 has a nozzle surface 78 extending in the apparatus depth direction (the direction of arrow D in the figure), and the nozzle surface 78 is formed with a plurality of nozzles 78 </ b> A for ejecting ink droplets. Has been.

  As shown in FIG. 15, the maintenance mechanism 80 is arranged along the apparatus depth direction, which is the rotation axis direction of the image recording drum 52. The maintenance mechanism 80 includes a moving unit 82 for moving the inkjet head 56, a cap unit 84 for preventing the ink in the nozzle 78A from drying, and a wiping unit 86 for wiping off ink adhering to the nozzle surface 78. It has. The image recording drum 52, the wiping unit 86, and the cap unit 84 are arranged in this order in the apparatus depth direction.

  Further, the maintenance mechanism 80 includes a control unit 88 (see FIG. 12) that controls each unit, and an input device 138 to which information on the wiping member 102 provided in the wiping unit 86 is input.

[Mobile unit]
The moving unit 82 (an example of a first moving mechanism) moves the ink jet head 56 via a box-shaped support member 90 that collectively supports the ink jet heads 56 of the respective colors. The moving unit 82 includes a vertical mechanism 92 that moves the inkjet head 56 in the vertical direction of the apparatus (in the direction of arrow H in the drawing), and a horizontal mechanism 94 that moves the inkjet head 56 in the depth direction of the apparatus.

  The vertical mechanism 92 is arranged extending in the vertical direction of the apparatus. The vertical mechanism 92 includes a support portion 92A that supports the support member 90, a rail portion 92B that supports the support portion 92A so as to be movable in the vertical direction of the apparatus, and a support portion 92A that moves along the rail portion 92B. Drive unit.

  The horizontal mechanism 94 is arranged extending in the apparatus depth direction from the upper side of the image recording drum 52 to the upper side of the cap unit 84. The horizontal mechanism 94 includes a support portion 94A that supports a portion on the upper end side of the vertical mechanism 92, a rail portion 94B that supports the support portion 94A so as to be movable in the apparatus depth direction, and the support portion 94A along the rail portion 94B. And a drive unit (not shown) to be moved.

  In this configuration, the moving unit 82 collectively moves the ink jet heads 56 of the respective colors via the support member 90 under the control of the control unit 88 described later.

[Cap unit]
The cap unit 84 includes a housing 96 that is fixed to a frame member (not shown) and that opens upward, and a cap 98 that is disposed inside the housing 96 and against which the nozzle surface 78 of the inkjet head 56 is pressed.

  In this configuration, the nozzle surface 78 of the ink jet head 56 moved by the moving unit 82 is pressed against the cap 98, so that the ink in the nozzle 78A is prevented from drying.

[Wiping unit]
The wiping unit 86 includes four wiping devices 100M, 100K, 100C, and 100Y so as to correspond to the inkjet heads 56 of the respective colors. The wiping apparatuses 100M, 100K, 100C, and 100Y for the respective colors have basically the same configuration. In the following description, magenta (M), black (K), cyan (C), and yellow ( When there is no need to distinguish Y), M, K, C, and Y attached to the reference numerals are omitted.

  As shown in FIG. 14, the wiping device 100 includes a cassette 106 that houses a belt-like wiping member 102 that partially contacts a part of the nozzle surface 78 and wipes ink adhering to the nozzle surface 78. ing. Further, the wiping device 100 includes a moving module 108 that moves the cassette 106 in the vertical direction of the device, and a coating device 110 that applies a cleaning liquid to the wiping member 102.

[cassette]
The cassette 106 includes a casing 112 that is open at the top in the vertical direction of the apparatus, the wiping member 102 described above, and a plurality of rolls around which the wiping member 102 is wound.

  A winding roll 114A, a delivery roll 114B, and a counter roll 114C are arranged in this order from the bottom to the top on the center side in the apparatus depth direction in the casing 112, and are rotatably supported by the casing 112. Yes.

  The winding roll 114A receives a rotational force from a motor 140 (an example of a second moving mechanism, a transport mechanism) described later, and winds the belt-like wiping member 102. The feeding roll 114B The wiping member 102 wound up by the roll 114A is sent out. With this configuration, the wiping member 102 fed out from the feed roll 114B and taken up by the take-up roll 114A is moved by being conveyed along a predetermined movement path 111.

  The opposing roll 114 </ b> C is exposed to the outside from above the housing 112. The opposing roll 114 </ b> C is disposed between the delivery roll 114 </ b> B and the take-up roll 114 </ b> A in the movement path 111 and so as to face the nozzle surface 78 of the inkjet head 56 that is moved by the movement unit 82. The opposing roll 114C is driven to rotate as the wiping member 102 moves.

  In the movement path 111, a plurality of driven rolls 116 are disposed between the delivery roll 114B and the opposing roll 114C. In the movement path 111, a plurality of driven rolls 116 are disposed between the opposing roll 114C and the winding roll 114A. A driven roll 118 is disposed. Further, the cassette 106 is detachable from the maintenance mechanism 80 so that the wiping member 102 can be replaced.

  In addition, as the wiping member 102, as an example, a woven fabric woven from fibers formed of polyethylene terephthalate is used as the wiping member 102.

  In this configuration, a winding roll 114A to which a rotational force is transmitted from a motor 140 described later rotates in the direction of the arrow (clockwise) in the drawing to wind up the wiping member 102, and the delivery roll 114B is wound by the winding roll 114A. The wiping member 102 to be wound is sent out. Thereby, the wiping member 102 in a state where tension is applied is moved along the movement path 111 by being conveyed.

  The wiping member 102 that is transported and moved along the movement path is a portion that is wound around the opposing roll 114C, and the nozzle surface of the inkjet head 56 that is moved by the moving unit 82, as will be described in detail later. 78 is brought into contact.

[Moving module]
The moving module 108 is arranged extending in the vertical direction of the apparatus. Then, the moving module 108 moves along the rail portion 108B, a support portion 108A that supports the casing 112 of the cassette 106, a rail portion 108B that supports the support portion 108A so as to be movable in the vertical direction of the apparatus. And a drive unit (not shown).

  In this configuration, the moving module 108 moves the cassette 106 in the vertical direction of the apparatus under the control of the control unit 88 described later.

  The cassette 106 is moved by the moving module 108, and the standby position where the wiping member 102 is separated from the nozzle surface 78 and waits for the cleaning position where the wiping member 102 moves and contacts the nozzle surface 78 of the inkjet head 56. It is arranged at the position. This configuration will be described in detail with the action described later.

[Coating equipment]
The coating device 110 is a device that drops and applies a cleaning liquid (a liquid containing a surfactant) to the wiping member 102 that is transported and moved between the delivery roll 114B and the opposing roll 114C in the movement path 111. .

  The coating apparatus 110 includes a head 128 to which the cleaning liquid is dropped, a storage tank 130 that is disposed below the head 128 and stores the cleaning liquid, and a pump 134 that pumps the cleaning liquid from the storage tank 130 to the head 128 through the hose 132. It has.

  In this configuration, the pump 134 pumps the cleaning liquid from the storage tank 130 under the control of the control unit 88 described later, and the head 128 is attached to the portion of the wiping member 102 that is transported and moved between the delivery roll 114B and the opposing roll 114C. The washing liquid is dropped and applied. In addition, when the wiping member 102 where the cleaning liquid is applied by the coating device 110 moves to a position where the wiping member 102 is wound around the opposing roll 114C, the cleaning liquid is applied so that the cleaning liquid is absorbed by the wiping member 102. The amount of cleaning liquid to be determined is determined.

[Input device]
The input device 138 (see FIG. 15) is a device for the user to input information on the wiping member 102. Specifically, this is a device for inputting an absorption time per unit amount of ink in the wiping member 102 (hereinafter simply referred to as “liquid absorption time”).

Here, the liquid absorption time of the wiping member 102 can be quantified using a dropping method. Specifically, using a syringe, a unit amount (1 × 10 ⁻⁶ [m ³ ]) of ink is dropped on the wiping surface of the wiping member 102, and the ink droplet surface is not reflected. Measure the time until by a stopwatch. This measured time is the liquid absorption time.

[motor]
The motor 140 is attached to a frame (not shown) provided with the maintenance mechanism 80, and generates a rotational force transmitted to the take-up roll 114A as shown in FIG. As described above, the housing 112 is detachable from the maintenance mechanism 80. In other words, the housing 112 can be attached to and detached from the motor 140.

[Control unit]
As shown in FIG. 12, the controller 88 controls the moving unit 82, the moving module 108, the coating device 110, and the motor 140.

  In addition, control of each part by the control part 88 is demonstrated with the effect | action mentioned later.

(Function)
Next, a maintenance operation for the inkjet head 56 by the maintenance mechanism 80 will be described. Specifically, the image forming operation in which the ink droplets are ejected by the inkjet heads 56 of the respective colors onto the recording medium P conveyed by the image recording drum 52 is completed, and the operation is performed until the next image forming operation. The maintenance operation will be described.

  As shown in FIG. 4, the ink-jet heads 56 for the respective colors when the image forming operation is performed are arranged to face the outer peripheral surface of the image recording drum 52. The nozzle surface 78 of the inkjet head 56 and the outer peripheral surface of the image recording drum 52 form an image on the recording medium P conveyed to the image recording drum 52 by ink droplets ejected from the nozzle 78A (see FIG. 13). Is approaching.

  Further, the cassette 106 of the wiping device 100 is disposed at the standby position. Further, the motor 140 of the wiping device 100 is stopped.

  When the image forming operation is completed, the control unit 88 controls the vertical mechanism 92 of the moving unit 82 to move the inkjet head 56 upward as shown in FIG. As a result, the nozzle surface 78 of the inkjet head 56 and the outer peripheral surface of the image recording drum 52 are separated from each other.

  When the inkjet head 56 moves upward and stops, the control unit 88 controls the horizontal mechanism 94 of the moving unit 82, and as shown in FIGS. 6 and 7, the inkjet head 56 is moved to the back side in the apparatus depth direction ( Move to the right in the figure. Thereby, the inkjet head 56 moves above the cap unit 84 and stops. Since the cassette 106 is disposed at the standby position, the nozzle surface 78 of the inkjet head 56 and the wiping member 102 are separated from each other during the movement of the inkjet head 56 (see FIG. 6).

  When the inkjet head 56 stops above the cap unit 84, the control unit 88 controls the vertical mechanism 92 of the moving unit 82 to move the inkjet head 56 downward as shown in FIG. As a result, the nozzle surface 78 of the inkjet head 56 is pressed against the cap 98, and drying of the ink in the nozzle 78A is prevented. This state is maintained until the next image forming operation is started.

  When starting the next image forming operation, the control unit 88 controls the vertical mechanism 92 of the moving unit 82 to move the inkjet head 56 upward as shown in FIG. As a result, the nozzle surface 78 of the inkjet head 56 and the cap 98 are separated. Further, the control unit 88 controls the moving module 108 to move the cassette 106 upward and place the cassette 106 at the cleaning position.

  When the inkjet head 56 moves upward and stops, and the cassette 106 is disposed at the cleaning position, the control unit 88 controls the horizontal mechanism 94 of the moving unit 82. Then, as shown in FIGS. 10 and 11, the controller 88 moves the inkjet head 56 to the front side (left side in the drawing) in the apparatus depth direction. As a result, the inkjet head 56 moves above the image recording drum 52 and stops.

  As the inkjet head 56 moves, the control unit 88 controls the motor 140 of the wiping device 100 to transmit the rotational force to the winding roll 114A. As a result, the winding roll 114A rotates, and the wiping member 102 sent out from the sending roll 114B is transported along the movement path 111 and moved to be taken up by the winding roll 114A.

  Further, along with the movement of the wiping member 102, the control unit 88 controls the pump 134 of the coating device 110, pumps the cleaning liquid from the storage tank 130, and applies the cleaning liquid to the wiping member 102 by dropping it from the head 128. .

  Due to the movement of the inkjet head 56 and the arrangement of the cassette 106 at the cleaning position, the portion of the wiping member 102 wound around the opposing roll 114 </ b> C comes into contact with the nozzle surface 78 of the inkjet head 56. Specifically, the wiping member 102 comes into contact with the front side of the nozzle surface 78 in the apparatus depth direction. Then, the contact position is changed as the inkjet head 56 moves, and after the wiping member 102 comes into contact with a portion of the nozzle surface 78 in the apparatus depth direction, the nozzle surface 78 and the wiping member 102 are separated from each other.

  Further, by applying the cleaning liquid to the wiping member 102 and moving (winding) the wiping member 102, the portion of the wiping member 102 to which the cleaning liquid is applied contacts the nozzle surface 78. Specifically, the portion of the wiping member 102 that is wound around the opposing roll 114 </ b> C and contacts the nozzle surface 78 is changed by the movement (winding) of the wiping member 102. Thereby, the ink adhering to the nozzle surface 78 is wiped off by the wiping member 102, and the nozzle surface 78 is cleaned.

  Note that the moving speed of the inkjet head 56 controlled by the control unit 88 (hereinafter referred to as “first moving speed”) and the moving speed of the wiping member 102 (hereinafter referred to as “second moving speed”). It will be described later.

  When the inkjet head 56 moves and stops above the image recording drum 52, the control unit 88 controls the vertical mechanism 92 of the moving unit 82, and moves the inkjet head 56 downward as shown in FIG. Thus, the nozzle surface 78 of the inkjet head 56 and the outer peripheral surface of the image recording drum 52 face each other, and the next image forming operation can be performed. Further, the control unit 88 controls the moving module 108, moves the cassette 106 downward, and places the cassette 106 at the standby position.

  Thereby, the maintenance operation by the maintenance mechanism 80 ends.

  Next, the first movement speed and the second movement speed controlled by the control unit 88 will be described.

  The control unit 88 determines the first movement speed and the second movement speed based on the liquid absorption time of the wiping member 102 input from the input device 138. In the present embodiment, a conversion table in which the first moving speed and the second moving speed are determined for each liquid absorption time of the wiping member 102 is stored in the control unit 88. And the control part 88 determines a 1st moving speed and a 2nd moving speed using this conversion table.

  The conversion table for determining the first moving speed and the second moving speed is determined by considering the following four viewpoints.

  1. A viewpoint of suppressing generation of streaks in the output image due to air bubbles being drawn into the inkjet head 56 from the nozzles 78A and no ink droplets being ejected from the nozzles 78A.

  2. The viewpoint of suppressing the remaining wiping of the ink adhered to the nozzle surface 78.

  3. A viewpoint of suppressing ink from being pulled out from the nozzle 78 </ b> A when ink adhering to the nozzle surface 78 is wiped off and the ink surface is left on the nozzle surface 78.

  4). The viewpoint which suppresses the consumption of the wiping member 102.

[Viewpoint to suppress streaks in output image]
First, items to be studied from the viewpoint of suppressing the occurrence of streaks in the output image will be described after describing the comparative embodiment.

  In the maintenance mechanism 200 according to the comparative embodiment, the moving speed of the wiping member 102 does not change based on the liquid absorption time of the wiping member 102. In the maintenance mechanism 200, the wiping member 102 having a relatively short liquid absorption time is used.

  In the maintenance mechanism 200, as shown in FIGS. 17A and 17B, when the ink in the nozzle 78A of the moving inkjet head 56 comes into contact with the moving wiping member 102, the wiping member 102 absorbs it. The ink in the nozzle 78A is pulled out of the nozzle 78A by the force. Furthermore, as the inkjet head 56 moves, the nozzle 78A and the wiping member 102 are separated from each other as shown in FIG. Then, bubbles are drawn into the ink jet head 56 from the nozzle 78A by the reaction of the ink pulled out from the nozzle 78A.

  As described above, in the maintenance mechanism 200 according to the comparative form, when bubbles are drawn into the inkjet head 56, ink droplets are not ejected from the nozzles 78A, and streaks may occur in the output image.

  On the other hand, the first movement speed and the second movement speed controlled by the control unit 88 of the maintenance mechanism 80 of the present embodiment are determined based on the liquid absorption time of the wiping member 102.

  Specifically, in order to reduce the amount of ink drawn from the nozzle 78A, the contact time between the ink in the nozzle 78A and the wiping member 102 is shortened as the liquid absorption time of the wiping member 102 is shortened. The first moving speed and the second moving speed are determined.

  The graph shown in FIG. 2 shows the relationship between the first movement speed and the second movement speed determined for each liquid absorption time of the wiping member 102. The horizontal axis of the graph indicates the first movement speed, and the vertical axis of the graph indicates the second movement speed.

  The straight line A1 indicates the case where the liquid absorption time is 10.0 [s] or more, the straight line B1 indicates the case where the liquid absorption time is 3.0 [s] or more and less than 10.0 [s], and the straight line C1 is The liquid absorption time is 1.0 [s] or more and less than 3.0 [s], and the straight line D1 indicates the liquid absorption time is 0.1 [s] or more and less than 1.0 [s]. ing.

  When the liquid absorption time is 10 [s] or more, a hatched range in which the first moving speed and the second moving speed are increased with respect to the straight line A1 is required from the viewpoint of suppressing the generation of streaks in the output image. The first moving speed and the second moving speed.

  That is, the straight line A1 indicates the lower limit values of the first moving speed and the second moving speed from the viewpoint of suppressing the occurrence of streaks in the output image. Then, in order to make the contact time between the ink in the nozzle 78A and the wiping member 102 shorter than a predetermined time, in the straight line A1, when the first movement speed is increased, the second movement speed is decreased. Note that the straight line B1, the straight line C1, and the straight line D1 have the same concept as the straight line A1.

  Further, when comparing the straight line A1, the straight line B1, the straight line C1, and the straight line D1, the first moving speed and the second moving speed are increased as the liquid absorption time of the wiping member 102 is shortened. In other words, in order to reduce the amount of ink pulled out from the nozzle 78A, the first is to shorten the contact time between the ink in the nozzle 78A and the wiping member 102 as the liquid absorption time of the wiping member 102 is shortened. The moving speed and the second moving speed are increasing.

[Viewpoint to prevent ink remaining on the nozzle surface from being wiped off]
Next, items to be examined from the viewpoint of suppressing wiping of ink remaining on the nozzle surface 78 will be described.

  When the first moving speed is increased, the time for the ink attached to the nozzle surface 78 to come into contact with the wiping member 102 is shortened, so that there is a possibility that ink remains on the nozzle surface 78. The speed at which this wiping residue occurs varies depending on the liquid absorption time of the wiping member 102. Specifically, the shorter the liquid absorption time of the wiping member 102 is, the shorter the absorption time of the ink attached to the nozzle surface 78, the higher the upper limit of the first movement speed.

  The graph shown in FIG. 1 shows the relationship between the first movement speed and the second movement speed determined for each liquid absorption time of the wiping member 102. Similar to the graph shown in FIG. 2, the horizontal axis indicates the first movement speed, and the vertical axis of the graph indicates the second movement speed. The graph shown in FIG. 1 also shows the above-described straight line A1, straight line B1, straight line C1, and straight line D1.

  The upper limit of the first moving speed from the viewpoint of suppressing the remaining unwiped ink adhering to the nozzle surface 78 is indicated in the graph by a straight line A2, a straight line B2, a straight line C2, and a straight line D2.

  A straight line A2 indicates a case where the liquid absorption time is 10.0 [s] or more, a straight line B2 indicates a case where the liquid absorption time is 3.0 [s] or more and less than 10.0 [s], and a straight line C2 indicates The liquid absorption time is 1.0 [s] or more and less than 3.0 [s], and the straight line D2 indicates the liquid absorption time is 0.1 [s] or more and less than 1.0 [s]. ing.

  As described above, the upper limit of the first moving speed increases as the liquid absorption time of the wiping member 102 becomes shorter.

[Viewpoint to suppress ink traces on nozzle surface]
Next, a description will be given of items that are examined from the viewpoint of suppressing ink from being drawn out from the nozzle 78A and causing ink drag marks on the nozzle surface 78.

  If the second moving speed is increased, the wiping member 102 may pull out the ink in the nozzle 78 </ b> A, and the ink trace may be left on the nozzle surface 78. The speed at which this ink drag mark varies depends on the liquid absorption time of the wiping member 102. Specifically, as the liquid absorption time of the wiping member 102 becomes shorter, the ink is drawn out from the nozzle 78A, so the upper limit of the second movement speed increases.

  The upper limit of the second moving speed from the viewpoint of suppressing the ink traces on the nozzle surface 78 is shown in the graph as a straight line A3, a straight line B3, a straight line C3, and a straight line D3.

  A straight line A3 indicates a case where the liquid absorption time is 10.0 [s] or more, a straight line B3 indicates a case where the liquid absorption time is 3.0 [s] or more and less than 10.0 [s], and a straight line C3 indicates The liquid absorption time is 1.0 [s] or more and less than 3.0 [s], and the straight line D3 indicates the liquid absorption time is 0.1 [s] or more and less than 1.0 [s]. ing.

  As described above, as the liquid absorption time of the wiping member 102 becomes shorter, the ink is drawn out from the nozzle 78A, so the upper limit of the second movement speed is increased.

  From the above three viewpoints, when the wiping member 102 having a liquid absorption time of 10.0 [s] or more is used, the first moving speed, and the oblique movement range surrounded by the straight line A1, the straight line A2, and the straight line A3, and A second moving speed is determined. When the wiping member 102 having a liquid absorption time of 3.0 [s] or more and less than 10.0 [s] is used, the wiping member 102 having a liquid absorption time of 1.0 [s] or more and less than 3.0 [s]. The same applies to the case where the wiping member 102 having a liquid absorption time of 0.1 [s] or more and less than 1.0 [s] is used.

[Perspective to reduce consumption of wiping members]
Next, the matter considered from a viewpoint of suppressing the consumption of the wiping member 102 is demonstrated.

  If the first moving speed is the same, the consumption of the wiping member 102 decreases as the second moving speed is decreased.

  Specifically, when the wiping member 102 having a liquid absorption time of 10.0 [s] or more is used, the second movement that is lowered most from the hatched range surrounded by the straight line A1, the straight line A2, and the straight line A3. The speed and the first movement speed corresponding to the second movement speed are determined. More specifically, the second moving speed and the first moving speed at the point A5 in the graph are determined. When the wiping member 102 having a liquid absorption time of 3.0 [s] or more and less than 10.0 [s] is used, the wiping member 102 having a liquid absorption time of 1.0 [s] or more and less than 3.0 [s]. The same applies to the case where the wiping member 102 having a liquid absorption time of 0.1 [s] or more and less than 1.0 [s] is used.

  An example of the conversion table in which the first moving speed and the second moving speed are determined by the above procedure is shown in the table of FIG. As shown in the table of FIG. 3, the controller 88 increases the first movement speed and the second movement speed as the liquid absorption time of the wiping member 102 becomes shorter.

(Summary)
As described above, the controller 88 adheres to the nozzle surface 78 even when the liquid absorption time of the wiping member 102 is different by determining the first moving speed and the second moving speed using the conversion table. It is possible to suppress ejection failure in which ink droplets are not ejected from the nozzle 78A after the ink is wiped off. Furthermore, the consumption of the wiping member 102 can be suppressed. In other words, the shorter the liquid absorption time of the wiping member 102, the higher the first movement speed and the second movement speed, so that even if the liquid absorption time of the wiping member 102 is different, the nozzle surface After wiping off the ink adhering to the nozzle 78, it is possible to suppress ejection failure in which ink droplets are not ejected from the nozzle 78A. Furthermore, the consumption of the wiping member 102 can be suppressed.

Second Embodiment
Next, an example of the droplet discharge device 170 according to the second embodiment of the present invention will be described with reference to FIG. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected, the description is abbreviate | omitted, and a different part from 1st Embodiment is mainly demonstrated.

(Constitution)
The maintenance mechanism 172 of the droplet discharge device 170 according to the second embodiment does not include an input device that inputs the liquid absorption time of the wiping member 102. As shown in FIG. 18, the maintenance mechanism 172 includes a lead-out member 176 used for deriving the liquid absorption time of the wiping member 102, and a detection member 178 that detects attachment of the cassette 106 to the maintenance mechanism 172. I have. Further, in addition to the operation of the control unit of the first embodiment, the control unit 180 of the maintenance mechanism 172 controls the lead-out member 176 to absorb the liquid of the wiping member 102 when the cassette 106 is mounted on the maintenance mechanism 172. The time is derived. The operation of the control unit 180 will be described together with the operation described later.

  A well-known photo interrupter is used as the lead-out member 176, and the lead-out member 176 is disposed so as to face the wiping member 102 where the cleaning liquid is dropped by the head 128.

  The lead member 176 includes a light emitting element 176A and a light receiving element 176B. The light emitted from the light emitting element 176A is reflected by the liquid surface and received by the light receiving element 176B, whereby the output voltage of the lead-out member 176 changes.

(Function)
Next, a derivation operation in which the liquid absorption time of the wiping member 102 is derived by the control unit 180 will be described.

  When all of the wiping member 102 is wound on the winding roll 114 </ b> A, the wiping member 102 is replaced by replacing the cassette 106 with a new cassette 106.

  When replacing the cassette 106, the cassette 106 is detached from the maintenance mechanism 172 and a new cassette 106 is mounted on the maintenance mechanism 172. In other words, when all of the wiping member 102 is wound on the winding roll 114 </ b> A, the cassette 106 is detached from the motor 140 and a new cassette 106 is mounted on the motor 140. When the cassette 106 is mounted, the cassette 106 is arranged at the standby position.

  When a new cassette 106 is mounted on the maintenance mechanism 172, the detection member 178 detects that a new cassette 106 is mounted on the maintenance mechanism 172. Then, the control unit 180 receives the detection signal of the detection member 178.

  When the control unit 180 receives the detection signal from the detection member 178, the control unit 180 controls the pump 134 of the coating apparatus 110 to drop the cleaning liquid from the head 128 onto the wiping member 102. In this state, the motor 140 is stopped.

  Further, the control unit 180 controls the lead-out member 176 to irradiate the cleaning liquid dropped toward the wiping member 102 with light. The light emitted from the light emitting element 176A is reflected by the liquid surface of the cleaning liquid and received by the light receiving element 176B, whereby the output voltage of the lead member 176 changes. The cleaning liquid is gradually absorbed by the wiping member 102, and the cleaning liquid does not protrude from the wiping surface of the wiping member 102. Then, the output voltage of the outlet member 176 returns to the state before the cleaning liquid is dropped. The controller 180 counts the time of output voltage change and derives the liquid absorption time. If there is a difference between the time for the cleaning liquid to be absorbed by the wiping member 102 and the time for the ink to be absorbed by the wiping member 102, the control unit 180 considers the difference in advance and sets the liquid absorption time. To derive.

  Then, the control unit 180 determines the first moving speed and the second moving speed based on the derived liquid absorption time.

  Thereby, the operation | work which a user inputs the liquid absorption time of the wiping member 102 can be eliminated.

  In addition, every time the wiping member 102 is replaced, the liquid absorption time of the wiping member 102 can be derived.

  Other operations are the same as those of the first embodiment except that the input device performs.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. This will be apparent to those skilled in the art. For example, in the first embodiment and the second embodiment, only the inkjet head 56 is moved in the apparatus depth direction. However, the wiping device 100 may be moved, and the inkjet head 56 and the wiping device 100 may be moved. You may move relatively in the apparatus depth direction.

  In the first and second embodiments, the conversion table is based on the assumption that the nozzle surface 78 of the inkjet head 56 and the wiping member 102 are moved in opposite directions (so-called counters). However, the conversion table may be determined on the assumption that the movement is performed in the same direction.

  Although not specifically described in the first embodiment and the second embodiment, when the nozzle surface 78 of the inkjet head 56 is pressed against the cap 98, the thickened ink is discharged from the nozzle 78A. Maintenance operations may be performed.

  In the first embodiment, the first moving speed and the second moving speed are determined based on the liquid absorption time of the wiping member 102 input from the input device 138. For example, in the cassette 106, A recording medium in which the liquid absorption time of the wiping member 102 is stored may be attached, and the control unit 88 may obtain the liquid absorption time of the wiping member 102 from this recording medium.

  In the second embodiment, the control unit 180 counts the output voltage change time and derives the liquid absorption time. However, the controller 180 adds the function of counting the output voltage change time to the derivation member 176 and derives it. The member 176 may derive the liquid absorption time by counting the time of the output voltage change.

  Although not specifically described in the first embodiment and the second embodiment, the degree of streaks generated in the output image depends on the physical properties of the ink, the nozzle diameter, and the pressing force on the nozzle surface 78 of the wiping member 102. And the back pressure in the head during the maintenance operation. Therefore, the first moving speed and the second moving speed need to be individually examined in advance.

  Although not specifically described in the first embodiment and the second embodiment, the amount of liquid that can be absorbed by the wiping member 102 (liquid absorption capacity) is the amount of cleaning liquid to be absorbed and the amount to be absorbed. Is sufficiently larger than the amount of ink (ink drawn out from the nozzle 78A and ink attached to the nozzle surface 78).

  Although not specifically described in the second embodiment, when the liquid absorption time of the wiping member 102 is derived, when the liquid absorption time of the wiping member 102 is shortened, the liquid absorption time is derived. Derivation accuracy is improved by increasing the amount of the cleaning liquid dripped onto the wiping member 102.

10 Liquid droplet ejection device 56 Inkjet head (an example of a liquid droplet ejection head)
78 Nozzle surface 78A Nozzle 82 moving unit (an example of a first moving mechanism)
88 Control Unit 102 Wiping Member 140 Motor (Example of Second Movement Mechanism)
170 Liquid droplet ejection device 176 Deriving member 180 Control unit

Claims (5)

A droplet discharge head having a nozzle surface on which nozzles for discharging droplets are formed;
A wiping member that partly contacts a part of the nozzle surface and wipes off the liquid adhering to the nozzle surface;
A first moving mechanism for relatively moving the wiping member and the droplet discharge head;
A second moving mechanism for moving the wiping member and changing a portion in contact with the nozzle surface;
A first moving speed that controls the first moving mechanism to relatively move the wiping member and the droplet discharge head as the absorption time for the wiping member to absorb the liquid per unit amount becomes shorter. And a controller that controls the second moving mechanism and increases the second moving speed for moving the wiping member;
A droplet discharge device comprising: A derivation member used for deriving the absorption time of the wiping member;
The droplet discharge device according to claim 1, wherein the control unit controls the first moving mechanism and the second moving mechanism based on the absorption time derived by controlling the derivation member. The wiping member is detachable from the second moving mechanism,
When the wiping member is attached to the second movement mechanism, the control unit controls the first movement mechanism and the second movement mechanism based on the absorption time derived by controlling the derivation member. The droplet discharge device according to claim 2, wherein the droplet discharge device is controlled.   The liquid droplet ejection apparatus according to claim 1, wherein the second moving mechanism is a transport mechanism that transports the wiping member. A method of cleaning a nozzle surface having a droplet discharge head and formed with nozzles for discharging droplets,
A part of the nozzle surface is in contact with the nozzle surface, the wiping member for wiping off the liquid adhering to the nozzle surface, and the droplet discharge head are moved relatively, and the wiping member is moved, A step of changing a portion in contact with the nozzle surface,
As the absorption time for the liquid per unit amount to be absorbed by the wiping member becomes shorter, the first moving speed for relatively moving the wiping member and the droplet discharge head is increased, and the wiping member The nozzle surface cleaning method which raises the 2nd moving speed which moves the.

Images