JP5845782B2 - Inkjet printer - Google Patents

Description

  The present invention relates to an ink jet printer that records an image or the like on a recording medium.

  An ink jet printer has an ink jet head having a number of nozzles, and records an image or the like on a recording medium by ejecting ink droplets from the nozzles of the ink jet head onto the recording medium.

  By the way, in the inkjet printer, the ink ejected from the nozzle during recording of an image or the like, or the ink forcedly ejected from the nozzle by the purge operation for eliminating the ejection failure of the nozzle, May adhere to the surface. If this state is left unattended, it may cause various problems such as the landing position deviation of the droplets due to the adhered ink interfering with the droplets ejected from the nozzles, and nozzle clogging due to solidification of the adhered ink. Become. Therefore, a general ink jet printer includes a wiper that wipes ink adhering to the droplet ejection surface.

  For example, the ink jet printer of Patent Document 1 includes a timing belt disposed so as to face a droplet ejection surface of an ink jet head, and a wiper blade attached to the timing belt. In this configuration, when the timing belt runs, the wiper blade moves in a direction parallel to the droplet ejecting surface while being in contact with the droplet ejecting surface. Is wiped off by.

JP 2001-205816 A

  In the configuration of Patent Document 1, since the tip of the wiper blade slides with respect to the droplet ejection surface, the droplet ejection surface is worn by rubbing against the tip of the wiper blade. Further, there is a possibility that the droplet ejection surface is damaged when the wiper blade slides in a state where foreign matter is caught between the droplet ejection surface and the droplet ejection surface.

  An object of the present invention is to provide an ink jet printer capable of wiping off ink adhering to a droplet ejection surface without causing the droplet ejection surface to be worn or damaged.

An ink jet printer according to a first aspect of the present invention includes an ink jet head that has a liquid droplet ejecting surface in which a plurality of nozzles are open, ejects ink droplets from the plurality of nozzles toward a recording medium, and the liquid droplet ejecting surface. A belt that travels in a state of being opposed to the belt, belt driving means that drives the belt, a pressing member that is disposed on the opposite side to the droplet ejection surface with respect to the belt, and the pressing member that presses the belt against the belt The pressing member driving means for moving the pressing member in the direction along the droplet ejecting surface in a state where the belt is pressed against the droplet ejecting surface, and the belt driving means and the pressing member driving means are controlled. Control means ,
The inkjet head is for ejecting ink onto the recording medium in a state of being fixed at a predetermined recording position, and the belt faces the droplet ejection surface of the inkjet head at the recording position The belt is a transport belt that transports the recording medium, and moves while pressing the pressing member against the belt by the pressing member driving means in a state where the belt stops traveling by the control of the control means. By doing so, the ink adhering to the droplet ejection surface is pushed out and wiped off by the belt pressed against the droplet ejection surface.

  In the present invention, with the belt running stopped, the pressing member presses the belt against the droplet ejection surface, and the pressing member is moved in a direction along the droplet ejection surface. Thus, the belt pressing position of the belt by the pressing member, that is, the contact position with the droplet ejection surface of the belt is continuously changed, whereby the ink attached to the droplet ejection surface is pushed out by the belt and wiped off. In other words, the contact position of the belt with the droplet ejection surface only changes, and the belt does not slide relative to the droplet ejection surface, so the droplet ejection surface is worn or damaged when wiping ink. There is nothing to do.

Further, in the present invention, since the droplet ejection surface is wiped by the transport belt that transports the recording medium, a dedicated member for wiping the ink becomes unnecessary. In addition, since the ink is wiped off by a conveyor belt arranged opposite to the droplet ejection surface for the conveyance of the recording paper, the ink is quickly wiped off when the ink adheres to the droplet ejection surface. be able to. Furthermore, it is not necessary to move the ink jet head for wiping off ink, and the configuration of the printer is simplified.

Inkjet printer of the second invention, in the first invention, after wiping off the ink in the liquid droplet jetting surface by said conveyor belt, to remove the ink adhered to the conveyor belt, further comprising a cleaning means It is characterized by.

  According to the present invention, it is possible to reliably remove ink adhering to the conveyance belt and prevent the recording medium from being stained.

An ink jet printer according to a third aspect is the ink jet printer according to the second aspect , wherein the pressing member driving means moves the pressing member in a conveyance direction of the recording medium, and the cleaning means is the ink jet head. It is arrange | positioned in the downstream position of the said conveyance direction rather than.

  When the pressing member is moved in the transport direction and the ink adhering to the droplet ejection surface is pushed out by the transport belt and wiped off, the wiped ink is mainly in the downstream portion of the transport belt in the transport direction from the inkjet head. Adhere to. Here, since the cleaning means is disposed downstream of the inkjet head in the conveyance direction, the belt portion to which the ink is attached can travel to the downstream side in the conveyance direction, and the ink can be quickly removed by the cleaning means. The next transfer can be started immediately.

An ink jet printer according to a fourth aspect is characterized in that, in the third aspect , the width of the transport belt is larger than the width of the ink jet head.

  According to this configuration, when the ink adhering to the droplet ejection surface is wiped in the transport direction by the transport belt, the wiped ink is less likely to spill from the transport belt. In the present application, the “width of the ink jet head” means the length of the ink jet head in a direction parallel to the width of the transport belt.

An ink jet printer according to a fifth invention is characterized in that, in the first or second invention, the pressing member driving means moves the pressing member in the width direction of the transport belt.

  According to this configuration, by moving the pressing member in the width direction of the conveying belt, it is possible to wipe off the ink adhering to the droplet ejection surface in the width direction.

An ink jet printer according to a sixth aspect is characterized in that, in the fifth aspect , the width of the transport belt is larger than the width of the ink jet head.

  When the pressure member is moved in the width direction of the transport belt and the ink adhering to the droplet ejection surface is pushed out by the transport belt in the width direction and wiped off, the wiped ink is wider than the inkjet head of the transport belt in the width direction. It adheres mainly to the outer part. Since this portion is a portion that does not face the droplet ejection surface of the inkjet head, that is, a portion on which the recording medium is not placed, the recording medium is not easily contaminated.

An ink jet printer according to a seventh aspect of the present invention is the ink jet printer according to any one of the first to sixth aspects, wherein a wall projecting toward the liquid droplet ejection surface is provided at the widthwise end of the transport belt. It is characterized by.

  In this configuration, the ink wiped from the droplet ejection surface is less likely to spill from the conveyor belt.

An ink jet printer according to an eighth aspect of the present invention is the ink jet printer according to any one of the first to seventh aspects, wherein the specific portion of the transport belt is a wiping portion for wiping off the ink on the droplet ejection surface. It is.

  In the present invention, the ink adhering to the droplet ejection surface is wiped only at a specific part (wiping part) of the transport belt. That is, the ink adheres only to a specific wiping portion and does not adhere to other portions of the transport belt, so that the recording medium is hardly soiled.

An ink jet printer according to a ninth aspect is characterized in that, in the eighth aspect , the wiping portion is provided with a thin portion having a thickness thinner than other portions of the transport belt. is there.

  By providing the thin portion at the wiping portion for wiping off the ink on the droplet ejection surface, the bending rigidity of the wiping portion is reduced, and the wiping portion is easily deformed when the pressing member is pressed against it. Accordingly, the adhesion of the wiping portion to the droplet ejection surface is improved, and the ink can be reliably wiped off.

An ink jet printer according to a tenth aspect of the present invention is the ink jet printer according to the ninth aspect, wherein the thin portion is formed by forming a concave portion on a surface of the wiping portion opposite to the surface facing the droplet ejection surface. It is characterized by that.

  Since the surface of the wiping portion facing the droplet ejection surface is a smooth surface, the adhesion to the droplet ejection surface is further enhanced.

An ink jet printer according to an eleventh aspect of the invention is the ink jet printer according to any one of the eighth to tenth aspects, wherein the conveyance belt is formed with a plurality of adsorption holes for adsorbing the recording medium to be conveyed to the conveyance belt. In the wiping portion, the suction hole is not formed.

  Since the suction hole is not formed in the wiping portion of the conveyance belt, the ink wiped off from the droplet ejection surface by the wiping portion does not leak from the suction hole.

Inkjet printer of the twelfth aspect, in any one invention of the eighth to eleventh, before Symbol control means, wherein when the conveyance of the recording medium, wherein the said wiping portion of the conveyor belt the recording medium The belt driving means is controlled so as not to be placed.

  In the present invention, since the recording medium is not placed on the wiping portion for wiping off the ink adhering to the droplet ejection surface, the recording medium to be conveyed is not soiled with ink.

An ink jet printer according to a thirteenth invention is characterized in that, in any one of the first to twelfth inventions, the pressing member is a rotating roller.

  When the pressing member is a rotating roller, when the pressing member is driven by the pressing member driving means, the rotating roller moves in a direction along the droplet ejection surface while rotating. Therefore, when the pressing member moves, it is prevented that the belt is moved by contact friction and is slid with respect to the droplet ejection surface.

  According to the present invention, the position of contact with the droplet ejection surface of the belt is continuously changed, and the ink adhered to the droplet ejection surface is pushed out by the belt to wipe off the ink. That is, only the contact position of the belt with the droplet ejection surface changes, and the belt does not slide with respect to the droplet ejection surface, so that the droplet ejection surface is prevented from being damaged.

1 is a top view schematically illustrating an ink jet printer according to an embodiment. It is a side view of the principal part containing the recording part of the inkjet printer of FIG. FIG. 4 is a partially enlarged plan view of a conveyor belt. It is sectional drawing of the wiping part of a conveyance belt, (a) is the sectional view on the AA line of FIG. 3, (b) is sectional drawing on the BB line of FIG. 2A and 2B are side views of the ink jet printer during maintenance, in which FIG. 1A shows a capping state of a cap member, and FIG. 2B shows a state when ink on a droplet ejection surface is wiped off. It is a figure explaining the concrete structure and operation | movement of a cleaning mechanism. FIG. 2 is a block diagram schematically illustrating an electrical configuration of a printer. It is sectional drawing of the wiping off part of the conveyance belt which concerns on a modified form. It is a figure which shows operation | movement of the cleaning mechanism of another modified form. It is a figure which shows the cleaning mechanism of another modified form.

  Next, an embodiment of the present invention will be described. FIG. 1 is a top view schematically showing an ink jet printer according to this embodiment, and FIG. 2 is a side view of a main part including a recording unit of the ink jet printer of FIG. As shown in FIGS. 1 and 2, an inkjet printer 1 (hereinafter simply referred to as a printer 1) includes a recording unit 2 that records an image or the like on a recording sheet 100 that is a recording medium, and the recording unit 2 (particularly, an inkjet A maintenance unit 3 that performs maintenance of the head 10), a control device 4 that controls each part of the printer 1, and the like are provided.

  The recording unit includes an inkjet head 10 that ejects ink, and a transport mechanism 11 that transports a recording paper 100 that is a recording medium to the inkjet head 10.

  As shown in FIG. 1, the inkjet head 10 has a plurality of nozzles 13 arranged along a predetermined direction (main scanning direction) along a horizontal plane. The plurality of nozzles 13 constitute four nozzle rows 14 arranged in a direction (sub-scanning direction) orthogonal to the main scanning direction, and the lengths of these nozzle rows 14 are substantially the same as the width W3 of the recording paper 100. is there. The inkjet head 10 has a droplet ejection surface 10a in which the plurality of nozzles 13 are opened, and is fixed to the housing 6 in a posture in which the droplet ejection surface 10a faces downward. The ink jet head 10 ejects ink onto the recording paper 100 conveyed by the conveyance mechanism 11 while being fixed at a predetermined recording position facing the recording paper 100. The inkjet head 10 is a so-called fixed line head. The droplet ejection surface 10a is coated with an ink repellent film made of a fluororesin or the like. As a result, the ink repellency of the droplet ejection surface 10 a is increased and the ink is difficult to wet, and the ink is prevented from staying around the opening of the nozzle 13.

  The housing 6 is provided with a cartridge holder 5. The cartridge holder 5 is detachably mounted with ink cartridges 15 each storing ink of four colors (black (K), yellow (Y), cyan (C), and magenta (M)). The four ink cartridges 15 mounted on the cartridge holder 5 are supplied to the inkjet head 10 via the four tubes 12. Then, the four nozzle rows 14 (14K, 14Y, 14C, 14M) of the inkjet head 10 respectively eject the four color inks onto the recording paper 100 conveyed by the conveyance mechanism 11 described below. It has become. As shown in FIG. 1, among the four nozzle rows 14, three nozzle rows 14Y, 14C, 14M that eject three color inks (yellow, cyan, magenta) eject black ink. It is located upstream of the nozzle row 14K in the transport direction.

  As shown in FIG. 2, the transport mechanism 11 is disposed below the inkjet head 10. The transport mechanism 11 includes two pulleys 16 and 17, a transport belt 18, and a transport motor 19. The pulleys 16 and 17 are arranged at a distance so as to sandwich the inkjet head 10 in the sub-scanning direction. The conveyor belt 18 is stretched between two pulleys 16 and 17. The transport motor 19 (belt driving means) drives the pulley 16 to rotate and causes the transport belt 18 to travel. In the side view of FIG. 2, the conveyor belt 18 is shown in cross section.

  The conveyor belt 18 is an endless belt made of a flexible material such as rubber. Further, the upper portion 18e of the conveyor belt 18 is disposed in a state of facing the droplet ejection surface 10a of the inkjet head 10 with a slight gap. A recording paper 100 supplied from a paper feeding mechanism (not shown) is placed on the upper portion 18 e of the transport belt 18. When the two pulleys 16 and 17 are driven to rotate in the direction of the arrow in FIG. 2 by the transport motor 19, the transport belt 18 travels accordingly, and the recording paper 100 placed on the transport belt 18 It is conveyed along the droplet ejection surface 10a in a direction (conveyance direction) parallel to the sub-scanning direction. As shown in FIG. 1, the width W1 of the transport belt 18 is larger than the width W2 of the inkjet head 10 (the length in the main scanning direction parallel to the width direction of the transport belt 18) and is transported. It is larger than the width W3 of the recording paper 100.

  As shown in FIG. 2, an encoder 20 that detects the rotation angle and the number of rotations of the pulley 16 is attached to the pulley 16 that is positioned upstream in the transport direction. Based on the detection signal of the encoder 20, the control device 4 grasps the position of the recording paper 100 on the transport belt 18 and controls the transport of the recording paper 100 by the transport motor 19.

  FIG. 3 is a partially enlarged plan view of the conveyor belt 18. As shown in FIGS. 2 and 3, the transport belt 18 is formed with maintenance holes 18 a and a large number of suction holes 18 b. The maintenance hole 18a is a rectangular hole whose long side is slightly smaller than the width of the conveyor belt 18, and is a hole for allowing a cap member 23 of the maintenance unit 3 described later to pass therethrough. On the other hand, the suction hole 18b is a hole having a very small diameter compared to the maintenance hole 18a. The plurality of suction holes 18b are connected to a sheet suction device 39 (see FIG. 7) including a pump as a negative pressure source, an edge cutting valve, and the like. Then, the negative pressure generated by the paper suction device 39 is applied to the recording paper 100 at the positions of the plurality of suction holes 18b, so that the recording paper 100 is sucked and held on the transport belt 18 so as not to drop during transport.

  As will be described in detail later, in FIG. 3, the portion adjacent to the maintenance hole 18a of the conveyor belt 18 is a portion (wiping portion 21) for wiping off ink adhering to the droplet ejection surface 10a. 4A and 4B are cross-sectional views of the wiping portion 21 of the conveyor belt 18, wherein FIG. 4A is a cross-sectional view taken along line AA in FIG. 3, and FIG. 4B is a cross-sectional view taken along line BB in FIG. As shown in FIGS. 3 and 4, the wiping portion 21 is slightly larger than the inkjet head 10 (droplet ejection surface 10a) in plan view. Further, the suction hole 18 b is not formed in the wiping portion 21. At both ends in the width direction of the wiping portion 21, wall portions 18 c protruding upward (on the droplet ejection surface 10 a side) are formed by integral molding. Further, the concave portion 18d is formed on the inner surface of the wiping portion 21 (the surface opposite to the droplet ejection surface 10a), so that the wiping portion 21 has a thin portion 21a that is thinner than the other portions. Is provided. The wiping operation of the droplet ejection surface 10a by the wiping portion 21 and the reason why the above configuration is adopted for the wiping portion 21 will be described later.

  The maintenance unit 3 performs maintenance and recovery (maintenance) of the droplet ejection performance of the inkjet head 10, and is disposed inside the transport belt 18. 5A and 5B are side views of the inkjet printer 1 at the time of maintenance, in which FIG. 5A shows a capping state of the cap member 23, and FIG. 5B shows a state when the droplet ejection surface 10 is wiped off.

  As shown in FIG. 5, the maintenance unit 3 includes a cap member 23 made of an elastic member such as rubber, a suction pump 24 (see FIG. 7) connected to the cap member 23, and a transport belt 18 on the droplet ejection surface. And a cleaning mechanism 25 that wipes ink adhering to the ink 10a.

  The cap member 23 is driven up and down by a cap drive unit 26 (see FIG. 7) that includes a drive source such as a motor and a power transmission member such as a gear. As shown in FIG. 5A, when the cap member 23 is pushed up in a state where the maintenance hole 18a of the transport belt 18 is located immediately below the droplet ejection surface 10a of the inkjet head 10, the cap member 23 is maintained. It passes through the hole 18a and comes into close contact with the droplet ejection surface 10a of the inkjet head 10 to enter a capping state covering the droplet ejection surface 10a. In order to improve the sealing performance of the cap member 23 in the capping state, a seal member formed of silicon rubber or the like may be provided on the outer edge portion of the droplet ejection surface 10a that contacts the cap member 23. .

  In this capping state, the suction pump 24 forcibly discharges ink from the plurality of nozzles 13 of the inkjet head 10 by reducing the pressure in the cap member 23 (suction purge). Due to this suction purge, the nozzle 13 can be prevented from ejecting nozzles, or can cause ejection abnormalities such as ejection bending, foreign matter and bubbles mixed in the ink flow path, or thickened ink generated by drying in the nozzle 13, etc. 13 can be discharged.

  In the state where the maintenance hole 18a of the transport belt 18 is located directly below the droplet ejection surface 10a, the inkjet head 10 performs flushing for ejecting droplets from the nozzle 13 for the purpose of preventing the nozzle 13 from drying. You can also. Therefore, although not shown, the maintenance unit 3 also includes a liquid receiving portion that receives ink ejected by the flushing.

  The cleaning mechanism 25 is for wiping off the adhered ink with the transport belt 18 when the ink adheres to the droplet ejection surface 10a. As an example in which ink adheres to the droplet ejection surface 10a, first, when the above-described suction purge is performed, the ink discharged into the cap member 23 adheres to the droplet ejection surface 10a. Also, part of the ink ejected from the nozzles 13 may adhere to the droplet ejection surface 10a during image recording on the recording paper 100 or during the above-described flushing.

  FIG. 6 shows a specific configuration of the cleaning mechanism 25. As shown in FIGS. 5B and 6, the cleaning mechanism 25 includes a pressing roller 30 (pressing member) disposed on the lower side of the conveying belt 18 (on the side opposite to the droplet ejection surface 10 a), and the pressing roller. A roller driving mechanism 31 (pressing member driving means) that moves the pressing roller 30 in the conveying direction in a state where the conveying belt 18 is pressed against the droplet ejection surface 10a at 30.

  The pressing roller 30 is a cylindrical member that is the same as or longer than the width of the conveyor belt 18. As shown in FIG. 6, the pressing roller 30 is attached to the upper end portion of a roller support member 33 extending vertically so as to be freely rotatable. The roller drive mechanism 31 includes a main body portion 32, the roller support member 33, a vertical drive portion 34, and a wiping motor 35. The main body 32 is movable in the transport direction along the guide member 36. The roller support member 33 is attached to the main body part so as to be movable in the vertical direction, and is driven in the vertical direction with respect to the main body part 32 by the vertical driving part 34. The wiping motor 35 moves the main body 32 in the transport direction. Although the illustration of the specific configuration of the vertical drive unit 34 is omitted, for example, a screw mechanism (preferably a ball screw) including a screw shaft connected to a motor and a nut screwed to the screw shaft, an air cylinder, or the like is adopted. it can.

  When the roller support member 33 is driven upward by the vertical drive unit 34 from the standby state of FIG. 6A, the pressing roller 30 is pressed against the conveyor belt 18 as shown in FIG. A portion of the belt 18 (wiping portion 21) is pressed against the inkjet head 10. In this state, the main body 32 is driven in the transport direction by the wiping motor 35, so that the pressing roller 30 moves in the transport direction while rotating. As a result, the position of the conveyance belt 18 that contacts the droplet ejection surface 10a changes in the conveyance direction, and the ink (denoted by I) attached to the droplet ejection surface 10a is pushed out in the conveyance direction by the conveyance belt 18. Wiped away. When the ink wiping is completed, as shown in FIG. 6C, the roller support member 33 is driven downward by the vertical drive unit 34, and the pressing roller 30 is separated from the transport belt 18. In this state, the main body 32 is driven by the wiping motor 35 in the direction opposite to the conveying direction, and the pressing roller 30 returns to the standby state shown in FIG.

  As shown in FIGS. 3 and 5, a cleaning device 38 (cleaning means) is disposed at a position facing the outer peripheral surface of the pulley 17 located downstream of the inkjet head 10 in the transport direction. The cleaning device 38 removes ink adhering to the wiping portion 21 of the transport belt 18 after wiping the droplet ejection surface 10a. The configuration of the cleaning device 38 is not limited to a specific one. For example, the cleaning device 38 includes an absorber that absorbs ink, and an urging unit that urges the absorber in a direction approaching / separating from the conveyance belt 18. Can be configured.

  Next, the electrical configuration of the printer 1 will be described with reference to the block diagram of FIG. As illustrated in FIG. 7, the control device 4 of the printer 1 illustrated in FIG. 7 includes, for example, a central processing unit (CPU) that is a central processing unit, and various programs and data for controlling the overall operation of the printer 1. Is stored in a ROM (Read Only Memory) and a microcomputer including a RAM (Random Access Memory) that temporarily stores data to be processed by the CPU. A program stored in the ROM is executed by the CPU. Thus, the overall operation of the printer 1 is controlled. Alternatively, the control device 4 may be a combination of various circuits including an arithmetic circuit.

  The control device 4 includes a recording control unit 40 that controls a recording operation on the recording paper 100 by the recording unit 2. The recording control unit 40 further controls a head control unit 41 that controls the inkjet head 10, and a conveyance control unit that controls a conveyance motor 19 of the conveyance mechanism 11 and a sheet suction device 39 for attracting the recording sheet 100 to the conveyance belt 18. 42. Furthermore, the control device 4 includes a maintenance control unit 43 that controls the maintenance operation of the maintenance unit 3. The functions of the recording control unit 40 and the maintenance control unit 43 are actually realized by the operation of the above-described microcomputer constituting the control device 4 or the operation of various circuits including an arithmetic circuit. .

  Next, among the maintenance operations performed by the maintenance unit 3, particularly the ink wiping operation of the droplet ejection surface 10 a will be described in detail below.

  When wiping the droplet ejection surface 10a of the inkjet head 10, first, the conveyance control unit 42 controls the conveyance motor 19 to cause the conveyance belt 18 to travel. And as shown in FIG.5 (b), the wiping off part 21 is moved to the position facing the droplet ejection surface 10a. This control is enabled by the conveyance control unit 42 grasping the position of the wiping portion 21 of the conveyance belt 18 based on the signal input from the encoder 20.

  3, 5A, and 5B, the wiping portion 21 of the transport belt 18 is adjacent to the upstream side in the transport direction with respect to the maintenance hole 18a. Therefore, as shown in FIG. 5A, when the droplet ejection surface 10a is wiped after the suction purge or the flushing in the state where the maintenance hole 18a is directly below the droplet ejection surface 10a, FIG. ), The wiping portion 21 can be made to face the liquid droplet ejection surface 10a only by running the transport belt 18 for a while. Therefore, it is possible to promptly shift to the wiping operation of the droplet ejection surface 10a after completion of the suction purge or the like.

  In the state before the droplet ejection surface 10a is wiped off, as shown in FIG. 6A, in the cleaning mechanism 25, the pressure roller 30 is lowered from the inkjet head 10 to a position where it does not contact the transport belt 18. Is also waiting at a position upstream in the transport direction. In this state, when the cleaning mechanism 25 (in particular, the vertical drive unit 34 and the wiping motor 35) is controlled by the maintenance control unit 43, the droplet ejection surface 10a is wiped as follows.

  The droplet ejection surface 10a is wiped off while the transport belt 18 is stopped. First, it is driven by the wiping motor 35 and the main body 32 moves in the transport direction. At the same time, the pressing roller 30 is driven upward by the vertical driving unit 34 and pressed against the conveying belt 18. As a result, as shown in FIG. 6B, one portion of the wiping portion 21 of the transport belt 18 is locally pushed up by the pressing roller 30 and pressed against the droplet ejection surface 10 a of the inkjet head 10.

  When the pressing roller 30 moves in the transport direction in this state, the contact position of the wiping portion 21 of the transport belt 18 with the droplet ejection surface 10a continuously changes in the transport direction, and the wiping portion 21 is moved to the droplet ejection surface 10a. The ink adhering to the ink (indicated by reference numeral I) is wiped off by pushing it downstream in the transport direction. In this wiping operation, the pressing position of the transport belt 18 by the pressing roller 30, that is, the contact position of the transport belt 18 with the droplet ejection surface 10a only changes continuously. That is, since the transport belt 18 does not slide with respect to the droplet ejection surface 10a, the droplet ejection surface 10a is prevented from being worn or damaged. In particular, in the configuration in which the droplet ejection surface 10a is coated with an ink repellent film as in the present embodiment, the ink repellent film is prevented from being damaged and the droplet ejection surface 10a is prevented from being easily wetted with ink.

  Further, since the droplet ejection surface 10a is wiped by the conveyance belt 18 that conveys the recording paper 100, a dedicated member for wiping the droplet ejection surface 10a becomes unnecessary. Further, in order to convey the recording paper 100, the ink is wiped off by pressing the conveying belt 18 disposed opposite to the droplet ejecting surface 10a against the droplet ejecting surface 10a. When the ink adheres to the ink, the wiping operation can be performed quickly. Further, since it is not necessary to move the inkjet head 10 whose recording position is fixed when wiping ink, the configuration of the printer 1 is simplified.

  In this embodiment, the pressing member that presses the conveying belt 18 against the droplet ejection surface 10 a is a rotating roller (pressing roller 30), and the pressing roller 30 is conveyed while rotating while being pressed against the conveying belt 18. Move in the direction. Accordingly, the contact friction with the transport belt 18 becomes very small. Therefore, when the pressing roller 30 moves, the wiping portion 21 of the transport belt 18 is moved in the transport direction by being caught by the contact friction, and the liquid droplets are dropped. Sliding with respect to the ejection surface 10a is prevented.

  When wiping of the droplet ejection surface 10a by the wiping portion 21 of the conveyor belt 18 is completed, the pressing roller 30 is driven down to a position away from the conveyor belt 18 by the vertical drive unit 34, as shown in FIG. As a result, the wiping portion 21 returns to a state parallel to the droplet ejection surface 10a. Furthermore, the pressing roller 30 is returned to the standby position by being driven by the wiping motor 35 and moving the main body 32 in the direction opposite to the conveying direction.

  As shown in FIG. 3, a cleaning device 38 is disposed downstream of the inkjet head 10 in the transport direction. Then, after the above-described wiping operation by the wiping portion 21 is completed, the ink that has adhered to the wiping portion 21 can be reliably removed by the cleaning device 38 by running the conveyor belt 18. Accordingly, it is possible to prevent the recording paper 100 conveyed by the conveying belt 18 from being stained with ink.

  In the present embodiment, the pressing roller 30 presses the wiping portion 21 of the transport belt 18 against the droplet ejection surface 10a only when moving in the transport direction. That is, the wiping direction of the droplet ejection surface 10a by the wiping portion 21 is the transport direction. Accordingly, as shown in FIG. 6C, the wiped ink mainly adheres to a portion of the wiping portion 21 on the downstream side in the transport direction from the inkjet head 10. In addition, since the cleaning device 38 is disposed downstream of the inkjet head 10 in the transport direction, the cleaning device 38 can be simply moved by moving the transport belt 18 slightly and moving the wiping portion 21 downstream of the transport direction. Thus, the ink can be removed quickly, so that the next transport operation can be started immediately.

  The wiping direction of the droplet ejection surface 10a by the wiping portion 21 may be opposite to the transport direction, but a little trouble occurs when the ink attached to the wiping portion 21 is removed by the cleaning device 38. When wiping in the direction opposite to the transport direction, the ink adheres to the upstream end of the wiping portion 21 in the transport direction, contrary to FIG. At this time, if the cleaning device 38 is disposed downstream of the inkjet head 10 in the transport direction, it is necessary to pass the wiping portion 21 to which the ink has adhered again under the droplet ejection surface 10a. Then, there is a possibility that the wiped ink is reattached to the droplet ejection surface 10a and becomes dirty. Further, when the cleaning device 38 is arranged on the upstream side in the transport direction from the ink jet head 10, the transport motor 19 is rotated reversely only for this cleaning, and transported in the direction opposite to that during transport of the recording paper 100. The belt 18 needs to run. From the above, in this embodiment, the wiping direction is limited to the transport direction.

  Further, as shown in FIG. 1, in the present embodiment, among the four nozzle rows 14 that eject the four color inks, the black ink nozzle row 14K includes the three color ink nozzle rows 14Y and 14C. , 14M are arranged downstream in the transport direction. Therefore, by wiping the droplet ejection surface 10a only in the transport direction, it is possible to prevent black ink adhering to the droplet ejection surface 10a from entering the color ink nozzle 13 and causing color mixing. On the contrary, there is a possibility that the color ink enters the nozzle 13 of the black ink, but even if the color ink is mixed with the black ink, the print quality is hardly affected.

  Further, in the present embodiment, a specific part (wiping portion 21) of the transport belt 18 is opposed to the droplet ejection surface 10a, and the droplet ejection surface 10a is wiped by the wiping portion 21. That is, the ink adheres only to the wiping portion 21 by wiping off the droplet ejection surface 10a, and the ink does not adhere to the other portions, so that the recording paper 100 is not easily stained.

  In addition, the conveyance control unit 42 (belt control means) is configured to convey the recording motor 100 as follows so that the recording paper 100 is not placed on the wiping portion 21 as well as the maintenance hole 18a. To control. The conveyance control unit 42 grasps the positions of the maintenance holes 18 a and the wiping portion 21 of the conveyance belt 18 based on the signal input from the encoder 20. In addition, when the recording paper 100 is supplied from a paper feeding mechanism (not shown), if the maintenance hole 18a and the wiping portion 21 are located near the pulley 16 on the recording paper 100 supply side, the conveyance is performed. The control unit 42 controls the transport motor 19 to cause the transport belt 18 to travel. Thereby, the positions of the maintenance hole 18a and the wiping portion 21 are shifted to the downstream side in the transport direction. Thus, by preventing the recording paper 100 from being placed on the wiping portion 21, the recording paper 100 is further less likely to become dirty.

  Furthermore, as described below, the wiping portion 21 has a structure suitable for wiping off ink adhering to the droplet ejection surface 10a.

  First, as shown in FIG. 3 and FIG. 4, the thin portion 21 a is provided in the wiping portion 21 by forming the concave portion 18 d in the wiping portion 21. Thereby, the bending rigidity of the wiping part 21 falls, and when the press roller 30 is pressed, the wiping part 21 becomes easy to deform | transform. In particular, in the present embodiment, the size (area) of the thin portion 21a (recessed portion 18d) formed in the wiping portion 21 is larger than the droplet ejection surface 10a of the inkjet head 10, and the droplet ejection surface 10a. The wiping portion 21 is easily deformed over the entire area. Accordingly, the adhesion of the wiping portion 21 to the droplet ejection surface 10a is improved, and the ink attached to the droplet ejection surface 10a can be reliably pushed out and wiped off. Moreover, since the recessed part 18d which forms the thin part 21a is formed in the surface on the opposite side to the droplet ejection surface 10a of the wiping part 21, the opposing surface with the droplet ejection surface 10a of the wiping part 21 is smooth. And the adhesion to the droplet ejection surface 10a is further enhanced.

  Further, the wiping portion 21 is not formed with a suction hole 18 b for sucking the recording paper 100. Therefore, the ink wiped from the droplet ejection surface 10a by the wiping portion 21 does not leak down from the suction hole 18b.

  As shown in FIGS. 2 to 4, the width W <b> 1 of the conveyance belt 18 is larger than the width W <b> 2 of the inkjet head 10. In addition, wall portions 18c projecting toward the droplet ejection surface 10a are formed at both ends in the width direction of the wiping portion 21. As a result, the wiped ink is less likely to spill from the edge of the wiping portion 21. In FIG. 3, the wall portion 18 c is formed at the edge portion of the wiping portion 21, but the position inside the edge of the wiping portion 21 is within a range that does not interfere with the droplet ejection surface 10 a of the inkjet head 10. A wall 18c may be formed on the wall. Further, the wall portion 18 c is not formed only in the wiping portion 21, but may extend to the upstream portion in the transport direction and the downstream portion in the transport direction from the wiping portion 21.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] The shape of the wiping portion 21 can be appropriately changed as follows, for example. As shown in FIG. 8A, the thin portion 21 a of the wiping portion 21 may be smaller than the droplet ejection surface 10 a of the inkjet head 10. In this case, the effect of lowering the bending rigidity of the wiping portion 21 is smaller than that of the embodiment (FIG. 4B), but the advantage that the strength reduction of the conveyor belt 18 itself can be suppressed by reducing the thin portion. There is.

  Alternatively, as shown in FIG. 8B, a recess 18d may be formed on the upper surface of the wiping portion 21 (the surface on the droplet ejection surface 10a side). However, in this case, since the upper surface of the wiping portion 21 is uneven, the size of the recess 18d is larger than that of the inkjet head 10 so that at least the surface of the portion facing the droplet ejection surface 10a is a smooth surface. Is preferred.

  Further, the thinned portion 21a may be omitted when the conveyance belt 18 has a low bending rigidity and the wiping portion 21 is sufficiently in contact with the droplet ejection surface 10a without the thinned portion 21a.

2] In the above embodiment, the pressure roller 30 is moved in the transport direction by the roller driving mechanism 31 and the droplet ejection surface 10a is wiped in the transport direction. However, the pressure roller 30 is moved in the direction opposite to the transport direction (transport direction). The liquid droplet ejecting surface 10a may be wiped off by moving toward the upstream side. In addition, after the wiping operation is performed by moving the pressing roller 30 in the transport direction, the pressing roller 30 is kept on standby as it is, and when the droplet ejection surface 10a needs to be wiped next, the pressing roller 30 is moved in the transport direction. It may be moved to the opposite side and wiped off. That is, wiping may be performed in both directions.

  Further, as shown in FIG. 9, the roller driving mechanism 31 moves the pressure roller 30 in the width direction (main scanning direction) of the transport belt 18 perpendicular to the transport direction, so that the droplet ejection surface 10a is moved in the width direction. You may wipe it off. In this case, as shown in FIG. 9A, when the width of the transport belt 18 is larger than the width of the inkjet head 10, the ink wiped in the width direction is wider than the inkjet head 10 of the transport belt 18. It adheres mainly to the outer part in the direction. This outer portion is a portion that does not face the droplet ejection surface 10a of the ink jet head 10 and is a portion on which the recording paper 100 is not placed. Therefore, the recording paper 100 is not easily stained with ink. Further, when the wall portion 18 c is formed at the end in the width direction of the transport belt 18, the ink wiped off in the width direction is difficult to spill from the edge of the transport belt 18. In FIG. 9A, if the droplet ejection surface 10a is always wiped in the left direction in the figure, the wall portion 18c may be provided only at the left end portion of the transport belt 18.

  Alternatively, as shown in FIG. 9B, when the ink absorber 45 is installed below the edge of the transport belt 18 and the droplet ejection surface 10 a is wiped in the width direction of the transport belt 18, the transport belt A configuration in which the ink adhering to the 18 edge portions is collected by the ink absorber 45 may be adopted. In this case, since the ink adhering to the transport belt 18 is positively pushed out and collected to the ink absorber 45, the width of the transport belt 18 does not have to be so large as the width of the inkjet head 10, and The wall portion 18c shown in FIG. 9A is also unnecessary. However, also in FIG. 9B, it is difficult to push out all the ink adhering to the conveyance belt 18 to the ink absorber 45, and there is a possibility that the ink may remain at the end in the width direction of the conveyance belt 18. In this case, the width of the conveyance belt 18 may be larger than the width of the inkjet head 10 so that the recording paper 100 is not placed on the end of the conveyance belt 18 where ink may remain. .

3] The cleaning mechanism 25 is not limited to the configuration of the above-described embodiment (FIG. 6), and various configurations can be employed. Hereinafter, some modified examples of the cleaning mechanism 25 will be described.

  In FIG. 10A, a guide member 46 having a guide surface 46a raised in a region facing the droplet ejection surface 10a is installed on the opposite side across the inkjet head 10 and the conveyance belt 18. The main body portion 32 that supports the pressing roller 30 moves along the guide surface 46a of the guide member 46, so that the pressing roller 30 presses the conveying belt 18 against the droplet ejecting surface 10a and the droplet ejecting surface 10a. Move along. Note that when the spring 47 is interposed between the main body portion 32 and the pressing roller 30, the pressing roller 30 is more reliably pressed against the transport belt 18.

  10B, the main body 32 is movable along a guide shaft 48 parallel to the droplet ejection surface 10a, and a roller support member 33 connected to the pressing roller 30 is connected to the main body 32. Is inserted to be movable up and down. Further, a guide member 46 having a guide surface 46a raised in a region facing the droplet ejection surface 10a is installed at a position further below the guide shaft 48, and the lower end of the roller support member 33 is the guide surface 46a. Abut. In this configuration, when the main body 32 moves along the guide shaft 48, the roller support member 33 is pushed up while moving along the guide surface 46a, so that the pressing roller 30 presses the conveying belt 18 against the droplet ejection surface 10a. It will move in the state.

  Further, in FIG. 10C, the pressing roller 30 is connected by a rotating shaft 51 and an arm 52. Then, when the pressing roller 30 rotates about the rotation shaft 51, the pressing roller 30 moves in a state where the conveying belt 18 is pressed against the droplet ejection surface 10a.

  In addition, the pressing member that presses the transport belt 18 against the droplet ejection surface 10 a is not necessarily a rotating roller, but it is preferable to make a device that reduces the contact resistance between the pressing member and the transport belt 18. For example, it is conceivable to increase the hardness of the contact portion of the pressing member with the conveyor belt 18 or to coat the contact portion to reduce the surface friction coefficient.

4] In the above embodiment, the recording paper 100 is controlled not to be placed on the wiping portion 21 for wiping the droplet ejection surface 10 a when the recording paper 100 is transported, but the recording paper 100 is also placed on the wiping portion 21. It may be placed and transported. Moreover, in the said embodiment, although the part of the conveyance belt 18 which wipes off the droplet ejection surface 10a was limited to the specific part (wiping part 21), the wiping part 21 is not specified but the conveyance belt 18 is unspecified. You may make it wipe off in the part. In this case, the ink may be wiped off at any part of the conveyor belt 18. Therefore, when the wall portion 18c is provided to prevent ink spillage as in the above-described embodiment, it is preferable that the wall portion 18c is formed over the entire length of the transport belt 18.

5] In the above embodiment, one inkjet head 10 has a plurality of nozzle rows 14 that eject ink of a plurality of colors (for example, four colors), but the inkjet head 10 is divided for each color. Also good. That is, a plurality of inkjet heads 10 that respectively eject a plurality of colors of ink may be arranged side by side in the transport direction. Also in this case, a configuration in which the droplet ejection surfaces 10a of the plurality of inkjet heads 10 are wiped by the transport belt 18 by the movement of one pressing member is possible, but the droplet ejection surfaces 10a of the plurality of inkjet heads 10 are A plurality of pressing members for wiping each may be provided.

6] Means for adsorbing the recording paper 100 to the conveyance belt 18 is not limited to that by suction from the adsorption hole 18b as in the above embodiment. For example, it is possible to employ means for charging the surface of the conveyor belt 18 to generate an electrostatic force with the recording paper 100 for adsorption.

7] Although the above embodiment is an example in which the transport belt 18 that transports the recording paper 100 is also used as a belt for wiping the droplet ejection surface 10a of the inkjet head 10, the belt for wiping the droplet ejection surface 10a is dedicated. It may be provided. In particular, when the inkjet head is a so-called serial type head that ejects ink while moving in the width direction of the recording paper, it is exclusively used for wiping at a position for maintenance away from the position facing the recording paper 100. A belt and a cleaning mechanism may be installed.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 4 Control apparatus 10 Inkjet head 10a Droplet ejection surface 13 Nozzle 18 Conveyor belt 18b Adsorption hole 18c Wall part 18d Recessed part 19 Conveyance motor 21 Wiping part 21a Thin part 30 Press roller 31 Roller drive mechanism 38 Cleaning apparatus 42 Conveyance control part 100 recording paper

Claims (13)

An inkjet head having a droplet ejection surface with a plurality of nozzles open, and ejecting ink droplets from the plurality of nozzles toward a recording medium;
A belt that runs in a state of facing the droplet ejection surface;
Belt driving means for driving the belt;
A pressing member arranged on the opposite side of the belt from the droplet ejection surface;
A pressing member driving means for moving the pressing member in a direction along the droplet ejecting surface in a state where the pressing member is pressed against the belt and the belt is pressed against the droplet ejecting surface;
Control means for controlling the belt driving means and the pressing member driving means ,
The inkjet head is for ejecting ink to the recording medium in a state of being fixed at a predetermined recording position,
The belt is a transport belt that travels in a state of facing the droplet ejection surface of the inkjet head at the recording position and transports the recording medium;
When the belt is stopped by the control of the control means, the pressing member driving means moves the pressing member while pressing the belt against the belt, so that the belt pressed against the droplet ejection surface is used. An ink jet printer for extruding and wiping off ink adhering to the droplet ejection surface. The inkjet printer according to claim 1 , further comprising a cleaning unit that removes ink adhering to the transport belt after the ink on the droplet ejection surface is wiped off by the transport belt. The pressing member driving means moves the pressing member in the conveyance direction of the recording medium,
The inkjet printer according to claim 2 , wherein the cleaning unit is disposed at a position downstream of the inkjet head in the transport direction. The inkjet printer according to claim 3 , wherein a width of the conveyance belt is larger than a width of the inkjet head. The pressing member driving means is an ink jet printer according to claim 1 or 2, characterized in that for moving the pressing member in the width direction of the conveyor belt. The inkjet printer according to claim 5 , wherein a width of the conveyance belt is larger than a width of the inkjet head. The widthwise ends of the conveyor belt, an ink jet printer according to any one of claims 1 to 6, characterized in that the wall portion projecting into the liquid droplet jetting surface side. The inkjet printer according to any one of claims 1 to 7 , wherein a specific part of the transport belt is a wiping portion for wiping off ink on the droplet ejection surface. 9. The ink jet printer according to claim 8 , wherein the wiping portion is provided with a thin portion having a thickness thinner than other portions of the transport belt. The inkjet printer according to claim 9 , wherein the thin portion is formed by forming a concave portion on a surface of the wiping portion opposite to the surface facing the droplet ejection surface. A plurality of suction holes for adsorbing the recording medium to be transported to the transport belt are formed in the transport belt,
The inkjet printer according to any one of claims 8 to 10 , wherein the suction hole is not formed in the wiping portion. Before SL control means, said during transportation of the recording medium, wherein the said wiping portion of said conveyor belt to the recording medium is not mounted, claims 8 to which and controls the belt drive means The inkjet printer according to any one of 11 . The pressing member is an ink jet printer according to any one of claims 1 to 1 2, characterized in that the rotating roller.