JP2009119652A - Image forming apparatus - Google Patents

Abstract

An object of the present invention is to prevent warping of a recording sheet with an easy configuration and prevent ink collected by being swept out of a wiping area after wiping from adhering to the recording sheet and soiling the recording sheet.
A carriage 20 capable of reciprocating movement and a nozzle surface 42a are exposed downward, and are held by the inkjet head 41 and the carriage 20 held by the carriage 20, and are arranged around the nozzle surface 42a together with the nozzle surface 42a. A droplet discharge device 13 that includes a holding component 40 that forms an exposed region E that is exposed downward, and a wiper 16 that is provided below the droplet discharge device 13 and that sweeps ink I adhering to the nozzle surface 42a out of the nozzle surface. And a pair of feed rollers 33 and 36 arranged to be spaced from each other in the feeding direction for feeding the recording medium 25 below the droplet ejection device 13. 13 is provided with convex portions 68 and 69 which are disposed between the pair of feed rollers 33 and 36 and whose front ends protrude downward from the lowermost surface of the exposed region E.
[Selection] Figure 7

Description

  The present invention relates to an image forming apparatus that discharges ink onto a recording medium such as an ink jet printer to form an image.

  The ink jet printer has a droplet discharge device including an ink jet head having a nozzle surface on which a nozzle group for ejecting ink is formed, and a carriage configured to hold the ink jet head and be reciprocally movable. An ink jet printer forms an image by causing ink to land on a recording paper by ejecting ink from a nozzle group of an ink jet head toward the recording paper fed by a paper feed mechanism while moving the carriage in the scanning direction. The printing operation is performed.

  Before the printing operation by the inkjet head or during printing, a flushing operation or a purge operation for discharging the thickened ink in the inkjet head from the nozzle is performed. Since the ink discharged from the nozzle adheres to the vicinity of the nozzle on the nozzle surface and affects the next ink discharge, the ink adhering to the nozzle surface is moved to a region where the nozzle group is not formed by the wiper blade (outside the wiping region). The wiping operation to sweep out is performed. This wiping operation is performed by moving the wiper blade to the nozzle surface, for example, moving the wiper blade relative to the nozzle surface of the stopped inkjet head, or moving the carriage having the inkjet head relative to the installed wiper blade. The ink on the nozzle surface is swept out of the wiping area by being moved relative to the nozzle surface in a state of being in contact with the nozzle. However, the ink swept out of the wiping area after this wiping operation may accumulate.

  In addition, the recording paper conveyed during printing may be bent or wavy due to warpage or cockling of the recording paper, or when the recording paper passes through a feed roller for conveying the recording paper. The recording paper may come into contact with the ink-jet head, for example, because the end is bounced. If the recording paper comes into contact with the nozzle surface of the inkjet head when the recording paper is transported, the recording paper will not be transported immediately and the printing operation will be stopped, or the ink that has been swept out of the wiping area will adhere to the recording paper. , The recording paper may become dirty or even the nozzle surface may be damaged. In order to solve such a problem, an ink jet printer shown in Patent Document 1 has been proposed.

  The ink jet printer of Patent Document 1 is provided with pressing members on the front, rear, left and right sides of the carriage (head holder of Patent Document 1). The pressing member has a roller, and is configured to press and hold the recording sheet in cooperation with the platen by pressing the roller against the recording sheet. The roller is configured to be rotatable, and continues to press and hold the recording paper while rolling on the recording paper even when the carriage is moving in the scanning direction. By pressing and holding the recording paper in this way, bending and undulation of the recording paper are suppressed, and contact of the recording paper with the nozzle surface is prevented.

Further, in the image forming apparatus of Patent Document 2, a collision warning sensor is arranged over the entire recording width of the image forming apparatus, that is, the entire width of the ink jet nozzle row of the print head, and detection of the floating of the recording medium that causes a collision is detected. Like to do.
Japanese Patent Laid-Open No. 7-61078 JP 2001-328246 A

  However, in Patent Document 1, since the recording paper is pressed and held by the pressing member, the ink adheres to the roller when the pressing member passes through the area on the recording paper where the image is formed. If the carriage continues to move, the ink attached to the rollers will adhere to the area of the recording paper where the image is not formed, which may contaminate the recording paper.

  In addition, in an ink jet printer, it is desired to reduce the size of ink droplets that are ejected in order to improve the resolution of an image formed on a recording sheet, and recording is performed in order to improve the landing accuracy of such small ink droplets. The gap between the paper and the nozzle surface is small. Since the pressing member has a roller and has a large outer dimension, it is difficult to dispose the pressing member in the gap, and it is necessary to provide the pressing member outside the carriage. Therefore, the distance between the front and rear pressing members and the distance between the left and right pressing members are increased, and it is difficult to suppress the bending and undulation of the recording paper within the gap. As a result, the recording sheet may come into contact with the droplet discharge device during conveyance of the recording sheet, and ink remaining outside the wiping area may adhere to the recording sheet and stain the recording sheet.

  In Patent Document 2, it is necessary to provide a complicated configuration such as arranging a sensor for detection and requiring a circuit for controlling the sensor, and the sensor may be erroneous depending on the type of the recording medium and the shape of the float. Sometimes it was detected.

  An object of the present invention is to suppress warping of a recording sheet with an easy configuration and prevent ink remaining outside the wiping area after wiping from adhering to the recording sheet and soiling the recording sheet.

  To achieve the above object, an image forming apparatus according to the present invention includes an inkjet head having a nozzle surface on which a nozzle group for ejecting ink is formed, a holding component disposed around the nozzle surface, and the inkjet head and the holding. A droplet discharge device including a carriage that holds a part and has a holding part that forms an exposed area that is exposed downward together with the nozzle surface and the holding part, and is configured to be reciprocally movable in a predetermined scanning direction; A pair of recording media which are arranged apart from each other in the transport direction intersecting the scanning direction so as to sandwich the exposed area and which should land the ink ejected from the nozzle group in the transport direction below the droplet discharge device. A feed roller and a lower part than the droplet discharge device, and move relative to the nozzle surface in a predetermined wiping direction to attach to the nozzle surface. A wiper that sweeps out the ink to be discharged, and the exposed area includes a wiping area that is wiped by the wiper, and an ink reservoir area in which the ink swept out of the wiping area is collected, The projection is disposed between the pair of feed rollers, and has a tip that protrudes downward from the lowermost surface of the exposed area.

  According to the above configuration, since the convex portion that protrudes downward from the lowermost surface of the exposed area including the nozzle surface is disposed between the pair of feed rollers, the recording medium is separated from the feed roller on the upstream side in the transport direction. Even if the recording medium is bent upward due to warping, jumping, cockling, etc., until it is sent below the droplet discharge device, that is, below the exposed area and guided to the downstream feed roller, Before the recording medium touches the exposed area, the recording medium comes into contact with the convex portion, and the recording medium is guided downward from the convex portion. As described above, since the recording medium is less likely to come into contact with the exposed area, the recording medium is immediately conveyed, and even if ink is accumulated in the ink accumulation area in the exposed area after the wiping operation, the recording medium is conveyed. Sometimes it is possible to prevent the recording medium from adhering to the ink and becoming dirty.

  Moreover, the said convex part may be provided in the at least one side of the said conveyance direction of the said holding | maintenance part. According to such a configuration, even if the recording medium sent to the lower side of the droplet discharge device from the feeding roller on the upstream side in the carrying direction is bent upward, before being conveyed below the exposed area including the nozzle surface. The recording medium is guided downward from the convex portion and guided to the downstream feed roller. In addition, when the recording medium is fed from the lower side of the exposed area to the downstream feed roller, even if the final end that is the free end bounces upward, the convex portion is formed on the downstream side. Be guided to. As described above, since the recording medium is less likely to come into contact with the exposed area, the recording medium is immediately conveyed, and even if ink is accumulated in the ink accumulation area in the exposed area after the wiping operation, the recording medium is conveyed. Sometimes it is possible to reliably prevent the recording medium from adhering to the ink and becoming dirty.

  In addition, at least an edge in a direction orthogonal to the wiping direction among the edges defining the wiping area is located in the exposed area, and the ink reservoir area extends in the wiping direction in the exposed area. It may be formed along the edge. According to such a configuration, since the ink reservoir area where the ink swept in the direction orthogonal to the wiping direction is collected is located in the exposed area, the ink may be scattered outside the exposed area by wiping. Reduced. As described above, it is possible to prevent the ink from adhering to the recording medium by the convex portion as described above even if the ink reservoir region is formed in the exposed region. In addition, since the convex portion is provided in the holding portion that is close to the edge with respect to the ink reservoir region formed at the edge, the recording paper guided downward by the convex portion can easily avoid the ink reservoir region. Therefore, it is possible to prevent ink from adhering to the recording medium and becoming dirty.

  The wiping area may include at least the entire area of the nozzle surface. According to such a configuration, the entire area of the nozzle surface is wiped, and the ink reservoir area is located outside the nozzle surface. That is, after the wiping operation, the ink attached to the nozzle surface is surely swept out of the nozzle surface. For this reason, the ink ejection operation after the wiping operation can be performed stably.

  Further, the holding portion may have an outer wall that surrounds and accommodates the holding component and the inkjet head, and the convex portion may be provided integrally with the outer wall. According to such a configuration, since the convex portion is integrally provided on the carriage, the convex portion can be integrally formed at the time of forming the carriage, and the above function can be achieved without increasing the number of parts and the processing steps. Can do.

  And a pair of guide rails that are spaced apart from each other in the transport direction and extend in the scanning direction, and the carriage is above the exposed area and sandwiches the exposed area in the transport direction. A pair of slide surfaces that are disposed apart from each other and are slidably mounted on each of the pair of guide rails, and a pair of restraining members that are disposed below each of the pair of guide rails, The pair of restraining members may restrict upward relative displacement of the carriage with respect to the pair of guide rails, and the convex portion may be provided on at least one of the pair of restraining members. According to such a configuration, the convex portion is provided in the existing configuration for restricting the upward displacement of the carriage, and the convex portion can be easily formed.

  The holding component may include a nozzle guide that protects the nozzle surface, and the nozzle guide may protrude downward from the nozzle surface and the holding portion. According to such a configuration, the nozzle surface can be protected by the nozzle guide, and the ink remaining in the lower surface of the nozzle guide after the wiping, or in the step or gap formed between the lower surface of the nozzle guide and the lower surface of the holding portion. Can be prevented from adhering to the recording medium.

  Moreover, the said convex part may be arrange | positioned in the upstream of the said conveyance direction of the said holding | maintenance part. According to such a configuration, even if the recording sheet from the upstream feed roller is bent upward, the recording medium is guided downward by the convex portion arranged on the upstream side in the transport direction, and below the droplet discharge device. To enter. In this way, it is possible to reliably prevent ink from adhering to the recording paper when entering the lower part of the droplet discharge device.

  Moreover, the said convex part may be arrange | positioned in the downstream of the said conveyance direction of the said holding | maintenance part. According to such a configuration, even if the recording medium below the droplet discharge device is bent upward, the recording medium is guided downward by the convex portion disposed on the downstream side in the feeding direction, and the downstream feeding is performed. You will be immediately guided to Laura. In particular, when the recording medium is fed from the lower side of the exposed area to the downstream feed roller, a convex portion is formed on the downstream side, such as when the final end that is the free end bounces upward. Be guided to.

  As is apparent from the above description, according to the present invention, the warping of the recording sheet is suppressed with an easy configuration, and the recording sheet is immediately conveyed from the upstream side to the downstream side, and ink remaining outside the wiping area after wiping is removed. It is possible to prevent the recording medium from being attached to the recording medium and being contaminated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the direction in which ink is ejected from the inkjet head is defined as the downward direction, and the opposite side is defined as the upward direction.

[First Embodiment]
FIG. 1 is a perspective view showing a multifunction machine 1 having an ink jet printer 3 (image forming apparatus) according to a first embodiment of the present invention. As shown in FIG. 1, the multifunction machine 1 has a printer function, a scanner function, a copy function, and a facsimile function, and has an inkjet printer 3 at the bottom of the casing 2 and a scanner at the top of the casing 2. 4. An opening 5 is formed on the front surface of the housing 2, a paper feed tray 6 of the ink jet printer 3 is provided below the opening 5, and a paper discharge tray 7 of the ink jet printer 3 is provided on the top. An opening / closing lid 8 is provided at the lower right portion of the front side of the inkjet printer 3, and a cartridge mounting portion 9 (see FIG. 2) is provided inside the opening / closing lid 8. An operation panel 10 for operating the inkjet printer 3, the scanner 4, and the like is provided on the upper front side of the multifunction device 1. The multifunction device 1 can also operate according to an instruction from an external personal computer (not shown).

  FIG. 2 is a plan view schematically illustrating the ink jet printer 3 shown in FIG. As shown in FIG. 2, the ink jet printer 3 includes a pair of guide rails that extend in the scanning direction (left-right direction in FIG. 2) and are spaced apart in a direction perpendicular to the scanning direction (up-down direction in FIG. 2). 11 and 12, and an image recording unit 13 (droplet discharge device) is supported on the guide rails 11 and 12 so as to be slidable in the scanning direction. The image recording unit 13 includes an inkjet head 41 (see FIG. 3) on which a nozzle group 55 (see FIGS. 4 and 6) for discharging ink onto a recording paper 25 (recording medium) (see FIG. 3) is formed. The timing belt 14 is wound around a pair of pulleys 15a and 15b. The timing belt 14 is disposed substantially parallel to the extending direction of the guide rail 12. One pulley 15a is provided with a carriage motor 76 (see FIG. 8) that drives forward and reverse rotation. When the pulley 15a is driven forward and reverse, the timing belt 14 reciprocates and the image recording unit 13 moves. It reciprocates in the scanning direction along the guide rails 11 and 12.

  Further, an optical linear encoder (not shown) is provided as detection means for detecting the position of the image recording unit 13 in the scanning direction and the moving speed in that direction, and a tape scale (not shown) as a component thereof is provided. Arranged along the scanning direction. Based on the position in the scanning direction of the image recording unit 13 detected by the detecting means, a wiping operation is controlled by a wiper blade 16 (wiper) described later.

  The image recording unit 13 includes a carriage 20 serving as a casing, and the carriage 20 is provided with four buffer tanks 21 that can store ink. Further, the above-described cartridge mounting portion 9 is provided on the front side of the guide rail 12. Four cartridges (black, cyan, magenta, yellow) of ink cartridges 22 are detachably mounted on the cartridge mounting portion 9. The ink cartridges 22 mounted on the cartridge mounting unit 9 are connected to the buffer tank 21 via ink supply tubes 23, respectively.

  The area scanned by the image recording unit 13 includes a printing area in which a printing operation for forming an image on the recording paper by ejecting ink from the nozzle group 55 toward the recording paper 25 (see FIG. 3) and a printing operation are performed. And maintenance areas that are not implemented. In the maintenance area, below the pair of guide rails 11 and 12, a wiper blade 16 (wiper) for wiping the nozzle surface 42a on which the nozzle group 55 is formed in order from the printing area side, the waste ink tray 17, and A purge mechanism 18 connected to a negative pressure suction pump 78 (see FIG. 8) is provided in parallel.

  The purge mechanism 18 includes a suction cap 19 having a rectangular opening formed at the upper end, and a cap moving mechanism 77 (see FIG. 8) that moves the suction cap 19 up and down. The suction cap 19 surrounds the outer periphery of the nozzle group 55 (see FIGS. 4 and 6) and comes into contact with the nozzle surface 42a (see FIGS. 3 to 6) when moved up by the cap moving mechanism 77. A rib 19a having a substantially rectangular frame shape protruding toward the surface and a rib 19b that divides a space surrounded by the rib 19a into two. In each space partitioned by the ribs 19b, discharge ports (not shown) connected to the negative pressure suction pump 78 (see FIG. 8) are formed.

  The wiper blade 16 is formed of an elastic material such as rubber in the form of a wide flat plate, and is erected so that its longitudinal direction is directed in a direction (vertical direction in FIG. 2) perpendicular to the scanning direction. Yes. The wiper blade 16 has an upper wipe position where the wiper blade 16 can come into contact with the nozzle surface 42a (see FIGS. 3 to 6) by the wiper moving mechanism 79 (see FIG. 8), and downward with respect to the nozzle surface 42a. The nozzle surface 42a can be contacted and separated by moving up and down between the separated retreat positions.

  In the maintenance area, a flushing operation for discharging the thickened ink to the waste ink tray 17, a purge operation for sucking the thickened ink from the negative pressure suction pump 78 from the nozzle group 55 (see FIGS. 4 and 6), and these After the above operation, a wiping operation for wiping off ink adhering to the nozzle surface 42a (see FIGS. 3 to 6) using the wiper blade 16 is performed. These maintenance operations are executed before the printing operation or when the user selects the execution of the maintenance operation on the operation panel 10 (see FIG. 1), and the printing operation is periodically stopped during the printing operation. Executed.

  In the flushing operation, in order to prevent clogging of the nozzles, the image recording unit 13 is moved to a position (flushing position) facing the waste ink tray 17 and ink unrelated to the image data is ejected. In this embodiment, the waste ink tray 17 is arranged in parallel with the purge mechanism 18 on one side (right side in FIG. 2) of the printing area, but the waste ink tray 17 is opposite to the purge mechanism 18 with respect to the printing area. It may be provided on the side (left side in FIG. 2), or may be arranged in the printing area in preparation for a platen 24 described later.

  In the purge operation, first, the image recording unit 13 is moved to a standby position (home position) facing the suction cap 19 of the purge mechanism 18, and the suction cap 19 is moved up by the cap moving mechanism 77 (see FIG. 8). 19, the ribs 19 a and 19 b are brought into contact with the nozzle surface 42 a (see FIG. 6) so as to surround the outer periphery of the nozzle group 55 (see FIG. 6), and the nozzle group 55 is surrounded by the ribs 19 a and 19 b of the suction cap 19. Seal inside.

  As shown in FIG. 6, on the nozzle surface 42a, there are formed five rows of nozzle groups 55 including two rows of nozzle groups 55B for black ink and three rows of nozzle groups 55C for other color inks. . FIG. 6 shows a cap region C indicating a range sealed by the suction cap 19, and the black ink nozzle group 55B is sealed in one of the two spaces partitioned by the ribs 19a and 19b. The other color ink nozzle group 55C is sealed in the other space.

  In the purge operation, the negative pressure suction pump 78 (see FIG. 8) is further driven in a state where the nozzle group 55 is sealed in this way to apply a negative pressure in the space surrounded by the ribs 19a and 19b. Ink is sucked from the nozzle group 55, and the ink sucked from each nozzle group 55 is discharged from a discharge port (not shown).

  When the image recording unit 13 is in a standby state in which no printing operation is performed, the state in which the nozzle group 55 is sealed is maintained in this way.

  In the wiping operation, the wiper blade 16 is moved up to the wipe position by the wiper moving mechanism 79, and the image recording unit 13 is moved from the home position or the flushing position so as to pass above the wiper blade 16. As a result, the wiper blade 16 moves relative to the image recording unit 13 with its tip bent and in contact with the nozzle surface 42a, and slides on the nozzle surface 42a and adheres to the nozzle surface 42a. Ink or the like is wiped by being slid by the wiper blade 16. When the wiping operation is not performed, the wiper blade 16 is positioned at the lower retracted position.

  The configuration for moving the wiper blade 16 relative to the wiper blade 16 is not limited thereto. For example, the wiper blade 16 is configured to be movable in the scanning direction, and the nozzle surface 42a of the image recording unit 13 stopped on the wiper blade 16 is used. Alternatively, the wiper blade 16 moved up by the wiper moving mechanism 79 may be moved in the scanning direction in contact with the wiper blade 16.

  As shown in FIG. 3, a paper feed tray 6 is disposed on the bottom side (lower side of FIG. 3) of the inkjet printer 3, and above the paper feed tray 6 and below the image recording unit 13. 24 is arranged.

  A path (hereinafter referred to as a transport path) 26 for transporting the recording paper 25 in the paper feed tray 6 extends from the back side portion of the paper feed tray 6. The conveyance path 26 has a curved path 27 that is curved in a substantially semicircular arc shape so as to be directed upward from the back side portion of the paper feed tray 6 toward the front side of the image recording unit 13, and from the end of the curved path 27 to the image recording unit. 13 includes a straight path 28 that extends substantially horizontally toward the front side of the paper 13 and passes through a printing region 29 between the platen 24 and the image recording unit 13 and is connected to the back side of the paper discharge tray 7 (see FIG. 1). It becomes. In the following description, the direction in which the straight path 28 extends is described as the conveyance direction of the recording paper 25, but the upstream side of this conveyance direction is the back side and the back side of the housing 1, and the conveyance direction The downstream side is the front side and the near side of the housing 1. This conveyance direction intersects the scanning direction of the image recording unit 13 at a right angle.

  The ink jet printer 3 includes a paper feeding mechanism 30 for feeding recording sheets stacked on the paper feed tray 6 one by one along the transport path 26 to the paper discharge tray 7 (see FIG. 1). The paper feed mechanism 30 includes a paper feed roller 31 that is rotatably provided between the upper and lower sides of the paper feed tray 6 and the platen 24, and a plurality of conveyance rollers 32 that are rotatably provided in the curved path 27 of the conveyance path 26. And a pair of feed rollers 33 and 36 provided at a predetermined interval across the platen 24 in the straight path 28 of the conveyance path 26.

  Of the pair of feed rollers 33 and 36, the feed roller 33 provided on the upstream side with respect to the platen 24 is composed of a pair of conveying rollers 34 and a pinch roller 35 disposed so as to face each other with the straight path 28 sandwiched from above and below. Each of the transport roller 34 and the pinch roller 35 is rotatable about an axis extending in a direction (scanning direction) orthogonal to the transport direction, and the pinch roller 35 has a predetermined pressing force with respect to the transport roller 34. It is urged downward to press. Further, the feed roller 36 provided on the downstream side with respect to the platen 24 includes a pair of paper discharge rollers 37 and a spur roller 38 disposed so as to face each other with the straight path 28 sandwiched from above and below. Each of the paper discharge roller 37 and the spur roller 38 is rotatable about an axis extending in a direction (scanning direction) orthogonal to the transport direction. It is urged downward so as to press with pressure.

  Of the paper feed mechanism 30, the paper feed roller 31, the transport roller 34, and the paper discharge roller 37 are rotated by the rotational driving force transmitted from the transport motor 75 (see FIG. 8). When the conveyance motor 75 is driven, the uppermost recording sheet among the recording sheets stacked in the sheet feeding tray 6 is sent to the curved path 27 of the conveyance path 26 by the sheet feeding roller 31, and is conveyed by the conveyance roller 32. It passes through the curved path 27 smoothly and is sent to the straight path 28.

  The recording sheet fed to the straight path 28 enters between the conveying roller 34 and the pinch roller 35 that form the upstream feeding roller 33, and is sandwiched up and down by these rollers 34 and 35. As a result, the rotation of the conveying roller 34 driven by the conveying motor 75 is transmitted to the recording sheet and the pinch roller 35 is driven, and the recording sheet is fed toward the downstream side of the straight path 28. The recording sheet from the upstream feed roller 33 passes through the printing area 29 and enters between the paper discharge roller 37 and the spur roller 38 forming the downstream feed roller 36, and is nipped up and down by these rollers 37 and 38. Is done. As a result, the rotation of the discharge roller 37 driven by the transport motor 75 is transmitted to the recording sheet and the spur roller 38 is driven, and the recording sheet from the downstream feed roller 36 is discharged from the discharge tray 7 (see FIG. 1). Sent to.

  The carriage 20 of the image recording unit 13 has a substantially box-like main body 20a on which the buffer tank 21 and the like are mounted, and a holding portion 20b provided at the lower part of the main body 20a. Are integrally formed. The main body 20a is joined to the timing belt 14 (see FIG. 2), and is slidably placed on the guide rails 11 and 12 (see FIG. 7) as will be described later. The holding portion 20b has four hanging walls (outer walls) 39 that extend downward from the main body portion 20a in a rectangular frame shape in plan view, and an accommodation space 39b is formed by being surrounded by an inner surface 39a of the hanging wall 39. Yes. The holding portion 20b holds a group of components such as a reinforcing frame (holding component) 40, an inkjet head 41, a nozzle protector 44, and the like that are accommodated in the accommodating space 39b and surrounded by the vertical wall 39.

  The inkjet head 41 includes a channel unit 42 having a rectangular shape in a plan view for guiding ink supplied from the buffer tank 21 from the inlet 42c to a number of nozzle groups 55 (see FIGS. 4 and 6), and the channel unit. And a piezoelectric drive actuator 43 that is stacked on the upper surface of 42 and selectively applies a discharge pressure toward the nozzle 55 to the ink in the flow path unit 42. The inkjet head 41 is fixed to the carriage 20 via the reinforcing frame 40.

  FIG. 4 is a cross-sectional view of a main part of the ink jet head 41 shown in FIG. As shown in FIG. 4, the flow path unit 42 has a structure in which a plurality of plates 50 to 54 having a plurality of openings that constitute ink flow paths are laminated and bonded. In the nozzle plate 50 arranged in the lowermost layer, a plurality of nozzles 55 are opened downward and arranged in a row, and the lower surface of the nozzle plate 50 forms a nozzle surface 42a. A plurality of pressure chambers 56 are formed in the uppermost plate 54, and are arranged in rows corresponding to the plurality of nozzles 55. An outlet channel 57 that communicates with the nozzle 55 is provided at one end of the pressure chamber 56, and a connection channel 59 that communicates with the common liquid chamber 58 is provided at the other end of the pressure chamber 56. The common liquid chamber 58 is arranged to extend in the column direction orthogonal to the scanning direction for each ink color so as to continuously overlap the plurality of pressure chambers 56 in plan view. Ink is supplied from the buffer tank 21 (see FIG. 3) to the common liquid chamber 58 from an inlet 42c (see FIG. 3) that opens to the upper surface of the flow path unit.

  The actuator 43 is formed in a rectangular shape in plan view having an outer shape smaller than that of the flow path unit 42, and exposes an inlet 42c (see FIG. 3) provided on one end side in the transport direction on the upper surface of the flow path unit 42. In this state, they are laminated and joined. The actuator 43 is formed by laminating a plurality of sheet-like piezoelectric bodies 60 made of PZT or the like, and is disposed so as to cover the pressure chamber 56. Among the piezoelectric bodies 60, a plurality of individual electrodes 61 are provided on the upper surface of the even-numbered piezoelectric bodies 60 from the bottom at locations corresponding to the plurality of pressure chambers 56. A common electrode 62 formed continuously corresponding to the plurality of pressure chambers 56 is provided on the upper surface. The actuator 43 is stacked with the flow path unit 42 with the individual electrode 61 facing the pressure chamber 56. In other words, the individual electrode 61 and the common electrode 62 are disposed so as to face each other so as to sandwich the single-layer piezoelectric body 60 excluding the lowermost layer and the uppermost layer piezoelectric body, and sandwiched between the individual electrode 61 and the common electrode 62. Each of the areas is a drive unit. Then, the drive signal is transmitted to the actuator 43 via the flexible wiring member 49 (see FIG. 5) on which the ejection driver 72 (see FIG. 8) that outputs a drive signal for driving the actuator 43 based on the image data is mounted. By selectively supplying to the individual electrode 61 and applying a voltage between the individual electrode 61 and the common electrode 62, a required portion of the piezoelectric body 60 is distorted in the stacking direction and the required volume of the pressure chamber 56 is changed. The ink is ejected from the nozzle 55.

  5 is a partially enlarged view of FIG. 3, and is a side sectional view of the ink jet head shown in FIG. 3 and its vicinity. As shown in FIGS. 3 and 5, the reinforcing frame 40 is formed in a rectangular frame plate shape, and the outer frame of the reinforcing frame 40 is formed in a rectangular shape that can be accommodated in the accommodating space 39b. The inner frame of the reinforcing frame 40 is formed in a rectangular shape smaller than the outer shape of the flow path unit 42 and slightly larger than the outer shape of the actuator 43. The reinforcing frame 40 has a rectangular central opening 40a surrounded by the inner frame. Have.

  The peripheral edge of the upper surface of the flow path unit 42 is fixed to the lower surface of the reinforcing frame 40, and the actuator 43 is disposed inside the central opening 40 a of the reinforcing frame 40 and is exposed upward. In this way, the reinforcing frame 40 is disposed so as to surround the periphery of the inkjet head and is provided integrally with the inkjet head 41. The reinforcing frame 40 is joined to the lower surface 20c of the carriage 20 that defines the accommodating space 39b, whereby the ink jet head 41 is fixed to the carriage 20 via the reinforcing frame 40. The reinforcing frame 40 is formed with an ink connection port that is connected to the inflow port 42c of the flow path unit 42, and ink from the buffer tank 21 enters the flow path unit 42c through the ink connection port. Supplied. The reinforcing frame 40 does not necessarily have such a frame plate shape, and may have a shape that does not block the trajectory of the ejected ink.

  The lower surface 20c of the carriage 20 that defines the accommodation space 39b is formed with an opening 20d that allows the internal space of the main body 20a to communicate with the central opening 40a of the reinforcing frame 40. The opening 20d is described above through the opening 20d. A flexible wiring material 49 is connected to the actuator 43 of the inkjet head 41.

  Further, a nozzle protector 44 (nozzle guide) for protecting the nozzle surface 42 a is attached to the lower side of the reinforcing frame 40 with an adhesive 45 in the accommodation space 39 b. The nozzle protector 44 is made of, for example, PBT / ABS resin and is formed in a rectangular frame plate shape. The outer frame of the nozzle protector 44 is formed in a rectangular shape that can be accommodated in the accommodating space 39 b, and the inner frame of the nozzle protector 44 is formed in a rectangular shape that is larger than the outer shape of the flow path unit 42. The nozzle protector 44 has a rectangular opening 44b surrounded by an inner frame, and the flow path unit 42 is arranged so that the nozzle surface 42a is exposed inside the opening 44b.

  An adhesive 45 is provided between the nozzle protector 44 and the inner surface 39a of the hanging wall 39 and between the nozzle protector 44 and the flow path unit 42 so that the ink wiped from the nozzle surface 42a by the wiping operation does not enter. It is filled as a sealing material. The sealing material may use the surplus adhesive 45 as described above, or may be provided separately from the adhesive 45.

  Thus, the inkjet head 41 is held by the reinforcing frame 40 and the nozzle protector 44 in the accommodation space 39b, and the periphery thereof is protected. Further, as shown in FIG. 5, the lower surface side of the carriage 20 is a receiving space such as the lower surface of the holding portion 20 b (that is, the lower surface 39 c of the hanging wall 39), the nozzle surface 42 a of the inkjet head 41, and the lower surface 44 a of the nozzle protector 44. An exposed region E is formed which includes a portion exposed downward in 39b.

  Further, the nozzle protector 44 is positioned below the nozzle surface 42 in order to protect the nozzle surface in the range of the exposed region E. The nozzle surface 42a is positioned below the lower surface 39c of the holding portion 20b. That is, in the exposed area E, the lower surface 44a of the nozzle protector 44, the nozzle surface 42a, and the lower surface 39c of the holding portion 20b are sequentially formed from the lower position.

  The nozzle protector 44 is bonded and fixed to the reinforcing frame 40 via an adhesive 45. For example, a dielectric elastomer is interposed between a pair of upper and lower electrode plates respectively joined to the lower surface of the reinforcing frame 40 and the upper surface of the nozzle protector 44. It is also possible to provide an elevating part that is mounted and configured such that when a voltage is applied between the electrode plates, the dielectric elastomer expands and contracts and the nozzle protector 44 moves up and down.

  FIG. 6 is a view of the inkjet head 41 shown in FIG. 3 and its vicinity as viewed from below. As shown in FIG. 6, the exposed area E includes a lower surface 39c of the holding portion 20b, a nozzle surface 42a of the ink jet head 41, a lower surface 44a of the nozzle protector 44, and the like. It is formed in a rectangular shape in plan view defined by the outer peripheral edge. The nozzle protector 44 is arranged at a small interval inside the inner surface 39a of the vertical wall 39 and at a small interval outside the flow path unit 42 of the inkjet head 41, and the nozzle surface 42a of the inkjet head 41 in plan view. It is arranged around. As described above, these minute intervals are filled with the adhesive 45 as a sealing material.

  Within the exposed area E, a wiping area W having a rectangular shape in a plan view showing a range in which the wiper blade 16 (see FIG. 2) moves relative to the image recording unit 13 (see FIG. 2) during the wiping operation is located. Yes. The wiper blade 16 has a dimension in the longitudinal direction that is arranged in parallel with the transport direction that is slightly longer than the dimension in the longitudinal direction of the nozzle surface 42a (see also FIG. 5). Since the image recording unit 13 passes over the wiper blade 16 in the scanning direction, the wiping operation is performed. Therefore, the dimension of the wiping area W in the transport direction is the dimension d1 of the wiper blade 16 in the transport direction (see also FIG. 2). The dimension in the scanning direction of the wiping area W is equal to the dimension d2 in the scanning direction of the exposed area E. Out of the edges defining the wiping area W, the edges extending in the scanning direction on both sides in the transport direction reach the lower surface 44a of the nozzle protector 44 over the edges on both sides in the transport direction of the nozzle surface 42a. As a result, the wiping area W includes the entire area of the nozzle surface 42a and overlaps a part of the lower surface of the nozzle protector 44. The wiper blade 16 is not only the nozzle surface 42a on which the nozzle group 55 is formed, but also the nozzle protector. A part of the lower surface 44a of 44 is also wiped off. Thus, the wiper blade 16 is set to be larger than the dimension of the nozzle surface 42a in the transport direction, so that the adhered ink can be reliably moved out of the nozzle surface 42a.

  Note that the wiping area only needs to be set so as to include at least the entire area of the nozzle surface 42a, and the range of the wiping area in the scanning direction is not limited to that described above, and the nozzle surface 42a on which the nozzle group 55 is formed. Or a region including the lower surface 44a of the nozzle protector 44 and the nozzle surface 42a. Further, the dimension in the longitudinal direction of the wiper blade 16 may be equal to or larger than the dimension in the transport direction of the nozzle surface 42a.

  Further, in the exposed area E, since the nozzle protector 44, the nozzle surface 42, and the lower surface 39c of the holding portion 20b are formed in order from the lower position, the wiper blade 16 first contacts the nozzle protector 44 during the wiping operation. Further, since the nozzle protector 44 and the nozzle surface 42 have a slightly stepped shape, when the wiper blade 16 slides, the boundary portion between the nozzle surface 42a and the nozzle protector 44, which is the stepped portion (conveyance in FIG. 6). And is slid at a position slightly apart in the scanning direction from the gap between them which is long in the direction. If the nozzle surface 42a and the nozzle protector 44 are configured to be flush with each other, there is a risk that the wiped ink may enter this boundary portion while the wiper blade 16 is sliding. As a result, the wiper blade 16 does not touch the boundary portion, so that the risk of ink entering can be reduced. In particular, in this embodiment, since the sealing material is provided at the boundary portion, the risk of ink entering can be further reduced.

  In the present embodiment, since the relative movement direction (wiping direction) of the wiper blade 16 during the wiping operation is the scanning direction, the ink adhering to the wiping area W is in a direction orthogonal to the wiping direction by the wiping operation. It will be swept to both sides in a certain transport direction. In this way, the ink swept out in the exposed area E and outside the wiping area W along the edge extending in the scanning direction among the edges defining the wiping area W. An ink reservoir region I that is easy to collect is formed. Specifically, in the ink reservoir region I, both ends of the lower surface of the nozzle protector 44 and the holding portion 20b in the transport direction and the gap between the nozzle protector 44 and the holding portion 20b (in this embodiment, an adhesive is used as a sealing material). In which the agent 45 is filled). In this way, the ink that is swept out by the wiping operation remains in the exposed area E and is less likely to scatter around the image recording unit 13.

  Further, the wiping area W includes the entire nozzle surface 42a, and the ink reservoir area I is formed at least outside the nozzle surface 42a. For this reason, the printing operation is resumed after the wiping operation, and the next printing operation can be stably performed without being affected by the ink swept out when the ink is ejected from the nozzle.

  In the present embodiment, the cap region C described above is located in the wiping region W. Ink may adhere to the upper end surfaces of the ribs 19a and 19b of the suction cap 19, and the ink may adhere to the portion of the nozzle surface 42a that contacts the suction cap 19 after the purge operation. Since the wiping operation is performed after such a purging operation, the ink adhering to the nozzle surface 42a from the suction cap 19 can also be swept out of the wiping region W.

  FIG. 7 is a side view of the image recording unit 13 shown in FIG. FIG. 7 also shows the side cross-sectional shapes of the pair of guide rails 11 and 12. As shown in FIG. 7, the main body portion 20 a of the carriage 20 straddles between the front end portion (downstream in the transport direction) of the guide rail 11 and the front end portion of the guide rail 12, and the holding portion of the carriage 20. 20 b is arranged between the guide rails 11 and 12. The guide rail 11 includes a main body portion 11a that extends horizontally and a flange portion 11b that is provided at the front end portion of the main body portion 11a. The flange portion 11b has an extending portion that extends upward from the front end portion of the main body portion 11a, and a tip portion that extends horizontally from the upper end of the extending portion toward the front side. The guide rail 12 includes a first horizontal portion 12a that extends horizontally on the back side (upstream side in the conveyance direction), an extension portion 12b that extends upward from a front end portion of the first horizontal portion 12a, and an upper end of the extension portion 12b. And a second horizontal portion 12c extending horizontally to the front side.

  A back side slide surface 63 that is slidably mounted on the top surface of the main body portion 11 a of the guide rail 11 is formed on the bottom side of the main body portion 20 a of the carriage 20. Further, a front side slide surface 64 that is slidably mounted on the upper surface of the second horizontal portion 12 c of the guide rail 12 is formed on the front side bottom portion of the main body 20 a of the carriage 20.

  The main body portion 20a of the carriage 20 has a wall 20e that extends up and down integrally with the rear wall 39, and a first stop piece (a stop member) 65 is provided protruding from the wall 20e to the front side. . The vertical wall 39 on the front side is provided with a second stop piece (a stop member) 66 protruding from the outer surface to the front side. Further, a wall 20f extending downward is provided at the front side end of the main body 20a of the carriage 20, and protrudes from the inner surface of the wall 20f to the back side, and a retaining portion 67 for preventing the carriage 20 from falling off. Is provided. The first and second stop pieces 65 and 66 and the retaining portion 67 are provided two apart from each other in the scanning direction.

  In a state where the back side slide surface 63 is supported on the upper surface of the main body portion 11 a of the guide rail 11, the distal end portion of the flange portion 11 b of the guide rail 11 is positioned above the first stop piece 65. In a state in which the front slide surface 64 is supported on the upper surface of the second horizontal portion 12 c of the guide rail 12, the front end of the first horizontal portion 12 a of the guide rail 12 is from the bottom surface of the main body portion 20 a of the carriage 20. Is also below and above the second stop piece 66. Further, the rear side end portion of the second horizontal portion 12 c of the guide rail 12 is positioned below the bottom surface of the main body portion 20 a of the carriage 20 and above the retaining portion 67. Therefore, for example, even when an upward force is applied to the image recording unit 13 when the suction cap 19 (see FIG. 2) moves up and comes into contact with the nozzle surface 42a in accordance with the purge operation, each stop piece 65 is operated. 66 are in contact with the lower surfaces of the guide rails 11 and 12. As described above, the image recording unit 13 is restricted from being displaced upward relative to the guide rails 11 and 12 by the first and second stop pieces 65 and 66.

  Further, the rear wall 39 is provided with a convex portion 68 protruding downward from the lower surface 39c. As shown in FIG. 6, two convex portions 68 are provided apart in the scanning direction. In addition, a convex portion 69 that protrudes downward is also provided integrally with a second stop piece 66 that is provided on the vertical wall 39 on the front side so as to be separated in the scanning direction. These convex portions 68 and 69 are disposed between the pair of feed rollers 33 and 36, and protrude below the lowermost surface of the exposed region E (the lower surface 44a of the nozzle protector 44 in the present embodiment). (See FIGS. 4 and 9). These four convex portions 68 and 69 have their lower end surfaces substantially flush with each other.

  FIG. 8 is a block diagram illustrating a configuration of the control unit 70 of the inkjet printer 3. The control unit 70 includes a CPU, a ROM, a RAM, and an input / output interface, and is configured to perform overall control of the operation of the inkjet printer 3 described above. As shown in FIG. 8, the operation panel 10 and the scanner 4 are connected to the control unit 70. The controller 70 also includes a transport driver 71 for driving the transport motor 75 described above, a discharge driver 72 for driving the actuator 43 of the inkjet head 41, and a scan for driving the carriage motor 76 described above. A driver 73 and a maintenance driver 74 for driving the cap moving mechanism 77, the negative pressure suction pump 78, and the wiper moving mechanism 79 are connected.

  The control unit 70 of the ink jet printer 3 outputs a control signal to the transport driver 71 based on image data sent from the scanner 4 or an external personal computer (not shown) and drives the transport motor 75 to transport the recording paper. The image recording unit 13 is reciprocated in the scanning direction in the printing area (see FIG. 2) by outputting a control signal to the scanning driver 73 and driving the carriage motor 76 while being intermittently conveyed. The control signal is output to drive the actuator 43 to discharge ink from the ink jet head 41 at an appropriate timing, and control to perform the printing operation is performed.

  Further, as described above, the control unit 70 scans the image recording unit 13 a predetermined number of times when the user selects execution of the maintenance operation using the operation panel 10, before the printing operation, or during the printing operation. The printing operation is interrupted regularly, and a predetermined maintenance operation is performed, so that the printing quality is not impaired.

  Taking as an example a maintenance operation performed during the printing operation, a procedure in which the control unit 70 performs the maintenance operation will be described with reference to FIG. When the controller 70 recognizes that it is time to perform the maintenance operation based on the elapsed time from the last maintenance operation, the number of scans of the carriage 20, etc., the printing operation is interrupted and the carriage motor 76 is driven to move the image recording unit 13 in the printing area to the home position described above. At this time, since the wiper blade 16 is located at the lower retracted position, the image recording unit 13 moves to the home position without contacting the wiper blade. After the image recording unit 13 is stopped at the home position, a control signal is output to the maintenance driver 74, the cap moving mechanism 77 is driven to move the suction cap 19 upward, and the negative pressure suction pump 78 is further driven. Thereby, a purge operation is performed. Next, the image recording unit 13 is moved to the aforementioned flushing position, a control signal is output to the ejection driver 72 to drive the actuator 43, and a predetermined amount of ink is ejected from the inkjet head 41 toward the waste ink tray 17. Let Thereby, control which performs a flushing operation is performed. By these purge operation and flushing operation, the ink thickened by drying around the nozzles and the ink including foreign matters attached around the nozzles are removed.

  When the purge operation and the flushing operation are thus completed, the wiper blade 16 is moved up from the retracted position to the wipe position by the wiper moving mechanism 79, and then the image recording unit 13 is moved to the printing area in order to resume the printing operation. Let Since the wiper blade 16 is disposed between the platen 24 and the waste ink tray 17, the image recording unit 13 passes over the wiper blade 16 and the wiping operation is automatically performed.

  When the printing operation is not being performed, the image recording unit 13 is located at the home position and the nozzle group 55 is maintained in a state of being sealed by the suction cap 19, so that the maintenance operation is performed before the printing operation. In this case, the purge operation can be performed only by driving the negative pressure suction pump without moving the image recording unit 13. Next, a flushing operation and a wiping operation are performed in the same procedure as described above.

  The procedure of the maintenance operation described above is an example, and the flushing operation or the purge operation may be performed alone.

  FIG. 9 is an operation explanatory diagram for explaining how the recording paper is conveyed through the printing area 29 during the printing operation of the inkjet printer 3 shown in FIG. In FIG. 9, the alternate long and two short dashes line extending between the pair of feed rollers 33 and 36 indicates the conveyance path of the recording sheet when the recording sheet without bending or undulation is conveyed. As shown in FIGS. 6 and 9, after the wiping operation, the ink swept out by the wiping operation is accumulated and remains on both sides of the conveying area outside the wiping area W in the exposed area E. Region I is formed.

  In this embodiment, since the lower surface 39c of the hanging wall 39 is lower than the lower surface of the nozzle protector 44, the ink swept from the nozzle surface 42a to the lower surface 44a of the nozzle protector 44 is also applied to the lower surface 39c of the hanging wall 39. May adhere. That is, as shown in FIG. 6, the ink reservoir region I extends from the outer edge of the wiping region W (including a part of the lower surface 44 a of the nozzle protector 44) to the lower surface 39 c of the hanging wall 39. However, the ink adhering to the lower surface 39 c of the hanging wall 39 does not possibly reach the lower surface of the convex portion 68 over the step surface between the lower surface 39 c and the lower surface of the convex portion 68.

  As shown in FIG. 9A, when the recording paper 25 sent from the upstream feed roller 33 to the printing area 29 is warped upward, the leading edge of the recording paper is first the lowermost surface of the exposed area E ( It abuts on a convex portion 68 provided on the rear wall (upstream side) 39 protruding downward from the lower surface of the nozzle protector 44. As a result, as shown in FIG. 9B, the leading edge of the recording paper 25 sequentially fed from the feed roller 33 is guided downward and enters the printing area 29 below the image recording unit 13. In this manner, the recording paper is guided to the printing area 29 so as to avoid the ink reservoir area I by the convex portion 68 provided on the upstream side in the transport direction on the vertical wall 39, and is prevented from being stained with ink. it can. 9A and 9B, the ink pool region I is formed along the wiping direction at the edge of the exposed region E in the transport direction, and the transport direction of the carriage 20 It is close to the convex portion 68 provided on the side. Therefore, the recording paper guided in contact with the convex portion 68 can be conveyed while avoiding the ink reservoir region I located in the immediate vicinity.

  Furthermore, as shown in FIG. 9C, even when the recording paper 25 in the printing area 29 is bent upward due to cockling or the like, before the recording paper 25 comes into contact with the exposed area E, the above-mentioned In addition to the convex portion 68, the convex portion 69 provided on the second stopping piece 66 also comes into contact, and the recording sheet is guided to the downstream feed roller 36 without adhering ink.

  Further, as shown in FIG. 9D, when the final end of the recording paper is guided to the upstream feed roller 33 and conveyed to the downstream feed roller, the final end of the recording paper that is the free end is It may bounce after passing the upstream feed roller 33. Also in such a case, since the final end of the recording paper contacts the convex portion 68 provided on the carriage conveyance direction side, the final end of the recording paper can be pressed downward as shown in FIG. It is possible to avoid the ink reservoir region I located immediately near the convex portion, and to guide the recording paper to the downstream feed roller 36 without adhering ink.

  As described above, in the present ink jet printer 3, the uppermost of the exposed area E between the pair of feed rollers 33, 36 provided on the upstream side and the downstream side of the printing area 29 on the upstream side and the downstream side in the transport direction. Protrusions 68 and 69 projecting downward from the lower surface are provided. For this reason, even if the recording paper 25 sent from the upstream feed roller 33 to the downstream feed roller 36 is bent upward, the recording paper first touches the exposed area E before the convex portions 68 and 69. After that, the recording paper is guided downward from the convex portions 68 and 69. As a result, the recording paper can be conveyed promptly to the downstream feed roller 36, and ink can be prevented from touching the ink reservoir area I remaining in the exposed area E after the wiping operation, and the ink contaminating the recording paper. Further, since the ink pool area I is formed along the wiping direction at the edge of the exposed area E in the transport direction, and the convex portions 68 and 69 are provided on the transport direction side, the convex portion 68. 69 and the ink reservoir area I are brought close to each other, and the recording paper guided downward by the convex portions 68 and 69 can be conveyed while avoiding the ink reservoir area I located nearest. The convex portions 68 and 69 are integrally provided on the lower surface of the hanging wall 39 and the second stop piece 66. Since the carriage 20 is formed by injection molding of a synthetic resin material, this convex portion can be easily provided without causing an increase in the number of parts or an increase in processing steps. Moreover, since the convex part 69 is formed in the regulation piece 66 conventionally provided in the carriage, it is easy to form and secure a space for arranging the convex part.

In the present embodiment, the wiping operation is performed when the image recording unit 13 passes over the wiper blade 16, and a pair of protrusions 66 and 68 are prevented from interfering with the wiper blade 16. Between the feed rollers 33 and 36, it is provided on both sides in the transport direction of the holding portion 20b. However, the scanning region of the wiper blade 16 is limited to only the nozzle surface 42a region where the nozzle group 55 is formed, or only the region including the lower surface 44a of the nozzle protector 44 and the nozzle surface 42a excluding the lower surface 39c of the holding portion 20b. For example, even if the convex portions are provided on both sides in the scanning direction of the holding portion 20b, there is no possibility that the wiper blade 16 interferes with the convex portions 68 and 69 during the wiping operation. When such a convex portion is provided, even if the recording paper passing below the exposed area E is bent upward, the convex portion 68, 69 comes into contact with the convex portions 68, 69 before touching the exposed area E. Guided downward from 69, the recording paper is less likely to contact the exposed area E. For this reason, the recording paper can be conveyed promptly and ink can be prevented from adhering to the recording paper.
[Second Embodiment]
Next, a second embodiment of the present invention will be described. This embodiment is different from the first embodiment in the positional relationship between the lower surface of the holding portion (that is, the lower surface of the vertical wall), the lower surface of the nozzle protector, and the nozzle surface, and the location where the convex portion is formed. Therefore, the wiping area and the ink reservoir area are different. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 10 is a cross-sectional view of the inkjet head 41 and the vicinity thereof in the inkjet printer of the second embodiment. FIG. 11 is a view of the inkjet head 41 shown in FIG. 10 and the vicinity thereof viewed from below. As shown in FIG. 10, the carriage 20 has a holding portion 20b provided in the lower portion of the main body portion similar to that of the first embodiment, and the holding portion 20b has a vertical wall 39 having a rectangular frame shape extending downward. Have. In the accommodation space 39b formed by being surrounded by the vertical wall 39, the reinforcing frame 40, the inkjet head 41 including the flow path unit 42 and the actuator 43, and the nozzle protector 44 are accommodated. The lower surface 44 a of the nozzle protector 44 is positioned below the nozzle surface 42 a, and the lower surface 39 c of the hanging wall 39 is positioned below the lower surface 44 a of the nozzle protector 44. That is, in the exposed area E, the vertical wall 39c, the nozzle protector 44, and the nozzle surface 42 are in this order from the lower position. In the case of such a configuration, the wiper blade 16 is abutted against one end of the lower surface 44a of the nozzle protector 44 in the accommodating space 39b surrounded by the hanging wall 39 as shown in FIG. The For this reason, the wiping region W does not include the lower surface 39c of the hanging wall 39 unlike the above embodiment, and the ink reservoir region I ′ extends from the outer edge of the wiping region W to the inner surface 39b of the hanging wall 39. The convex portion 168 is provided to protrude further downward on the lower surface 39 c of the hanging wall 39, and the convex portion 69 is also formed on the second locking portion 66. Both convex portions 168 and 69 have the same lower end surface.

  Also in the present embodiment, as in the first embodiment, it is possible to prevent the convex portions 168 and 69 from coming into contact with the ink pool area I ′ and being stained with respect to the bending of the recording paper conveyed. Further, the lower surface 39c of the hanging wall 39 that defines the exposed area E is located below the lower surface of the nozzle protector 44 where the ink pool area I ′ is formed. For this reason, the possibility that the ink swept out from the wiping area W is scattered outside the exposed area E is reduced.

[Third Embodiment]
Next, an ink jet printer (image forming apparatus) 103 according to a third embodiment of the present invention will be described. The inkjet printer 103 is provided in the lower part of the casing 2 shown in FIG. 1 in the same manner as in the first embodiment, and constitutes the multifunction machine 1. However, the wiping direction of the present embodiment is different from that of the first embodiment, whereby the wiping area and the ink reservoir area are different. In addition, the position of the bottom surface of the hanging wall is different from the position where the convex portion is formed. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 12 is a plan view showing the main configuration of the inkjet printer 103 according to the third embodiment of the present invention. As shown in FIG. 12, the wiper blade 116 is formed of an elastic material in a flat plate shape, and is erected so that the longitudinal direction is directed to the scanning direction, and the dimension in the longitudinal direction is the nozzle surface 42a (see FIG. 12). 15) is slightly larger than the dimension in the scanning direction. The wiper blade 116 has a wiper position at which an upper edge of the wiper blade 116 can come into contact with the nozzle surface 42a of the image recording unit (droplet discharge device) 113, and an upper end by a wiper lifting mechanism 179 (see FIG. 14) such as a parallel link mechanism. The edge is configured to move up and down between a retreat position away from the nozzle surface 42a, and can be moved in the transport direction by a wiper moving mechanism 180 (see FIG. 14) such as a rack and pinion mechanism. It is configured. At the normal time when the wiping operation is not performed, the wiper blade 116 is located at the retracted position, and is located at the far end or the near end (the near side in the illustrated example) of the movable range in the transport direction. Yes.

  FIG. 13 is a cross-sectional view of the ink jet head 41 and its vicinity of the ink jet printer 103 shown in FIG. As shown in FIG. 13, the carriage 120 has a holding portion 120b provided at the lower portion of the main body portion similar to that of the first embodiment, and the holding portion 120b has a rectangular frame-like hanging wall 139 extending downward. ing. In the accommodation space 139b formed surrounded by the vertical wall 139, the reinforcing frame 40, the inkjet head 41 including the flow path unit 42 and the actuator 43, and the nozzle protector 44 are accommodated. The lower surface of the nozzle protector 44 is positioned below the nozzle surface 42 a as in the second embodiment, and the lower surface 139 c of the hanging wall 139 is positioned below the lower surface 44 a of the nozzle protector 44.

  FIG. 14 is a block diagram showing a configuration of the control unit 170 of the inkjet printer 103 shown in FIG. The control unit 170 is connected to the operation panel 10, the scanner 4, the transport driver 71, the ejection driver 72, the scanning driver 73, and the maintenance driver 174. The maintenance driver 174 drives the motor 181 that provides driving force to the wiper lifting mechanism 179 and the wiper moving mechanism 180 described above, together with the cap moving mechanism 77 and the negative pressure suction pump 78. Also in this control unit 170, the maintenance operation is performed at the same timing as in the first embodiment, such as scanning the image recording unit 113 (see FIG. 12) a predetermined number of times during the printing operation.

  Referring also to FIG. 12, when the printing operation is interrupted, first, a control signal is output to the scanning driver 73 to move the image recording unit 113 in the printing area to the home position, and a control signal is output to the maintenance driver 174. Then, the control for performing the same purge operation as described above is performed. When the purge operation is completed, a control signal is output to the scanning driver 73 to move the image recording unit 113 to the flushing position, and a control signal is output to the ejection driver 72 to perform control to perform the same flushing operation as described above. .

  When the flushing operation is completed, a control signal is output to the scanning driver 73, the image recording unit 113 is moved above the wiper blade 116, and is stopped on the wiper blade 116. Then, a control signal is output to the maintenance driver 174 and the wiper lifting mechanism 179 is driven to move the wiper blade 116 upward. As a result, the upper edge of the wiper blade 116 comes into contact with one end side (see FIG. 13) of the lower surface 44a of the nozzle guide 44 on the downstream side in the transport direction. Next, a control signal is output to the maintenance driver 174 and the wiper moving mechanism 180 is driven to slide the wiper blade 116 in the transport direction. Accordingly, a wiping operation is performed in which the wiper blade 116 moves in the transport direction with respect to the nozzle surface 42a in a state where the wiper blade 116 is in contact with the nozzle surface 42a and the like and sweeps out ink adhering to the nozzle surface 42a.

  Next, a control signal is output to the maintenance driver 174, and the wiper lifting mechanism 179 is driven to move the wiping blade 116 down to the retracted position, thereby separating the wiper blade 116 from the nozzle surface 42a. When the wiping operation is thus completed, a control signal is output to the scan driver 73 to resume the printing operation, and the image recording unit 113 is moved to the printing area.

  FIG. 15 is a view of the inkjet head 41 shown in FIG. 13 and the vicinity thereof viewed from below. On the lower surface side of the carriage 120, the lower surface 139 c of the hanging wall 139 and a rectangular portion in plan view including a portion exposed downward in the accommodation space 39 b such as the nozzle surface 42 a of the inkjet head 41 and the lower surface of the nozzle protector 44. An exposed region E having a shape is formed.

  Within the exposed area E, a wiping area W having a rectangular shape in plan view is located. The wiping operation of the present embodiment is performed by moving the wiper blade 116 in the transport direction (wiping direction) with respect to the image recording unit 113 (see FIG. 12) stopped on the wiper blade 116 (see FIG. 12). Therefore, the dimension of the wiping area W in the transport direction is defined by the movable range d3 of the wiper blade 116 in the transport direction. Further, the dimension in the scanning direction of the wiping area W is defined by the dimension d4 in the scanning direction of the wiper blade 116 (see also FIG. 12). The dimension d4 is set to be smaller than the dimension of the exposed area E in the scanning direction and is set to be slightly larger than the dimension of the nozzle surface 42a in the scanning direction.

  Out of the edges that define the wiping area W, the edges that extend in the scanning direction on both sides in the transport direction exceed the edges on both sides in the transport direction of the nozzle surface 42 a and reach the lower surface 44 a of the nozzle protector 44. Similarly, of the edges that define the wiping area W, the edges extending in the scanning direction (wiping direction) on both sides in the scanning direction exceed the edges on both sides in the scanning direction of the nozzle surface 42 a, and the lower surface of the nozzle protector 44. Has reached. The result wiping region W includes the entire area of the nozzle surface 42 a and overlaps a part of the lower surface 44 a of the nozzle protector 44.

  In the present embodiment, since the wiping direction is the transport direction, the ink in the wiping area W is swept out to both sides in the scanning direction, which is a direction orthogonal to the wiping direction, by the wiping operation. Further, since the wiper blade 106 (see FIG. 10) reciprocates in the exposed area E and the wiping operation is performed, the ink in the wiping area W is removed from the edge that defines the wiping area W by the wiping operation. Of these, it tends to remain along the edges on both sides in the transport direction. Thus, the ink reservoir area I is formed so as to surround the wiping area W.

  Moreover, in this embodiment, it replaces with the convex part 68 (refer FIG. 4) provided in the vertical wall in the 1st Embodiment in four corners of the lower surface of the rectangular frame-shaped vertical wall 139, A convex portion 190 that protrudes downward is provided.

  FIG. 16 is a side view of the image recording unit 113 shown in FIG. As shown in FIG. 16, similarly to the first embodiment, the second stop piece 66 for restricting the upward displacement of the image recording unit 113 is provided with a convex portion 69 protruding downward. The convex portions 190 and 69 are disposed between the pair of feed rollers 33 and 36 and protrude below the lowermost surface of the exposed region E (the lower surface 139c of the hanging wall 139 in the present embodiment). Both convex portions 190 and 69 have the same lower end surface.

  FIG. 17 is an operation explanatory view for explaining a state in which the recording paper is conveyed through the printing area 29 during the printing operation by the inkjet printer 103 shown in FIG. In the present embodiment, as described above, the ink reservoir region I is formed on the lower surface of the nozzle protector 44 so as to surround the wiping region W (FIG. 17 shows the one formed on both sides in the transport direction). Since the lower surface of the nozzle protector 44 is above the lower surface 139c of the hanging wall 139, the ink adhering to the lower surface of the nozzle protector 44 is on the step surface between the lower surface of the nozzle protector 44 and the lower surface 139c of the hanging wall 139. Even if it accumulates, there is little risk of overcoming the step surface and adhering to the lower surface 139c of the hanging wall 139, and there is no possibility of adhering to the lower surface of the convex portion 190 provided on the lower surface of the hanging wall portion 139.

  As shown in FIG. 17A, when the recording paper 25 sent from the upstream feed roller 33 to the printing area 29 is warped upward, the leading edge of the recording paper is first of the corners of the hanging wall 139. It abuts on the convex portions 190 provided at the two corners on the back side. As a result, as shown in FIG. 17B, the leading edge of the recording paper 25 sequentially fed from the feed roller 33 is guided downward, and enters the printing area 29 below the image recording unit 113. As described above, the convex portion 68 provided on the upstream side in the transport direction can guide the recording paper so as to avoid the ink reservoir region I and enter the printing region 29 and prevent the recording paper from being stained with ink.

  Further, as shown in FIG. 17C, when the recording paper 25 in the printing area 29 is bent upward due to cockling or the like, before the recording paper 25 comes into contact with the exposed area E, the above-mentioned In addition to the two convex portions 190 on the back side, the convex portion 190 provided on the two front corners of the corners of the vertical wall 139 and the convex portion 69 provided on the second stop piece are in contact with each other. Thus, the recording sheet is guided to the downstream feed roller 36 without adhering ink.

  Further, as shown in FIG. 17D, when the final portion of the recording paper is guided to the upstream feed roller 33 and conveyed to the downstream feed roller 33, the recording paper serving as a free end is recorded. The final end may be bent so as to jump upward from the upstream feed roller 33. Also in such a case, since the final end of the recording paper that has bounced contacts the convex portion 190 before contacting the exposed area E, the final end is guided downward from the convex portion 190 as shown in FIG. The As a result, the recording sheet can be guided to the downstream feed roller 36 without adhering ink.

  As described above, also in the inkjet printer 103, the convex portion protruding below the lowermost surface of the exposed area E between the pair of feed rollers 33 and 36 provided on the upstream side and the downstream side of the printing area 29. 190, 69 are provided. Therefore, even if the recording paper 25 fed by the upstream feed roller 33 is bent upward, the recording paper hits the protrusions 190 and 69 before touching the ink reservoir area I in the exposed area E. After that, the recording sheet is guided downward from the convex portions 190 and 69. As a result, the recording sheet is promptly conveyed, and it is possible to prevent the recording sheet from being attached to the ink remaining in the exposed area E after the wiping operation and becoming dirty.

  Further, the lower surface of the hanging wall portion 139c that defines the exposed region E is located below the lower surface of the nozzle protector 44 where the ink reservoir region I is formed. For this reason, the possibility that the ink swept out from the wiping area W is scattered outside the exposed area E is reduced. Further, although the wiping direction is the transport direction, the wiping operation is performed by moving the wiper blade in the exposed area E. Therefore, the wiper blade is disposed outside the exposed area E in the wiping direction. There is no interference with the convex portion 68.

  Also in the second embodiment, for example, as in the first embodiment, the lower surface of the nozzle protector 44 is the lowest in the exposed region E, and the four convex portions are provided so that the convex portions do not interfere with the wiping direction. Only 190 may be provided. With this configuration, the wiping direction can be moved over the entire conveyance direction, and the recording paper is fed to the lower side of the exposed area E from the upstream feed roller 33 in the conveyance direction. Even if the recording paper 25 is bent upward until it is guided to the feed roller 36, the recording medium comes into contact with the convex portion before touching the exposed area, and the recording medium is guided downward from the convex portion. For this reason, the recording medium is less likely to come into contact with the exposed area, and the recording medium is promptly transported, and even when ink is accumulated in the ink reservoir area after the wiping operation, recording is performed when the recording medium is transported. The medium adheres to the ink and can be prevented from being stained.

  Although the embodiment of the present invention has been described above, the ink jet printer according to the present invention is not limited to the above configuration. As long as the convex portion is below the exposed area E, the arrangement position and the number of arrangement can be appropriately set according to the arrangement relationship between the wiper blade and the image recording unit, the wiping scanning direction, the scanning area, and the like. In addition, a wiping area W and an ink pool area are set.

  Further, the nozzle guide is not necessarily provided. Even in this case, the recording paper first comes into contact with the convex portion before coming into contact with the lowermost surface of the exposed area, and this recording paper can be prevented from being stained with ink.

  Further, as shown by a two-dot chain line in FIG. 7, a hook-shaped convex portion 191 may be additionally provided on the convex portions 68 and 69 so as to protrude downward from the outer surface of the vertical wall on the back side. It may replace with part 68 and may be provided. However, when the distance d5 between the pair of feed rollers 33 and 36 is narrower, the amount of deflection of the recording paper in the printing area can be suppressed. For this reason, as in the first and second embodiments, providing the protrusion only on the lower surface of the vertical wall secures a space for placing the upstream feed roller 33 close to the downstream feed roller 36. It is effective in doing. Accordingly, the bending of the recording sheet itself between the pair of feed rollers 33 and 36 can be suppressed, the effect of preventing the ink from adhering to the recording sheet is improved, and the gap between the nozzle surface and the platen is reduced. Thus, the ink landing accuracy can be improved.

  Further, the ink jet printers 3 and 103 of the above-described embodiment are configured to convey recording paper with the back side of the housing 1 as the upstream side in the transport direction and the front side of the housing 1 as the downstream side in the transport direction. However, this relationship may be reversed. In this case, the arrangement of the convex portions shown in the above embodiment is also reversed between the upstream side and the downstream side, and the warping or bending of the recording paper is suppressed downward in the same manner as described above, so that the recording paper can be quickly It is possible to prevent the recording paper from being soiled by the ink that is conveyed and adhered to the nozzle surface.

1 is a perspective view showing a multifunction machine 1 having an inkjet printer according to a first embodiment of the present invention. FIG. 2 is a plan view schematically illustrating the ink jet printer shown in FIG. 1. FIG. 2 is a partial cross-sectional view schematically illustrating the ink jet printer illustrated in FIG. 1. It is principal part sectional drawing of the inkjet head shown in FIG. FIG. 4 is a partially enlarged view of FIG. 3, and is a side sectional view of the inkjet head shown in FIG. 3 and the vicinity thereof. It is drawing which looked at the inkjet head shown in FIG. 3, and its vicinity from the downward direction. FIG. 4 is a side view of the image recording unit shown in FIG. 3. It is a block diagram explaining the structure of the control part of the inkjet printer shown in FIG. FIG. 6 is an operation explanatory diagram for explaining a state in which a recording sheet is conveyed through a print area during a printing operation of the ink jet printer shown in FIG. 1. It is a sectional side view of the ink jet head concerning the modification of a 2nd embodiment, and its neighborhood. It is drawing which looked at the inkjet head shown in FIG. 10, and its vicinity from the downward direction. It is a top view which illustrates typically the inkjet printer which concerns on 3rd Embodiment of this invention. FIG. 13 is a front sectional view of an ink jet head of the ink jet printer shown in FIG. 12 and its vicinity. It is a block diagram explaining the structure of the control part of the inkjet printer shown in FIG. It is drawing which looked at the inkjet head shown in FIG. 13, and its vicinity from the downward direction. It is a side view of the image recording unit shown in FIG. FIG. 13 is an operation explanatory diagram for explaining a state in which a recording sheet is conveyed through a printing area during a printing operation of the ink jet printer shown in FIG. 12.

Explanation of symbols

3 Inkjet printer (image forming device)
11, 12 Guide rail 13 Image recording unit (droplet discharge device)
16 Wiper blade 20 Carriage 20b Holding section 25 Recording paper (recording medium)
30 Paper feed mechanism 33, 36 Feed roller 39 Hanging wall (outer wall)
40 Reinforcement frame (holding parts)
41 Inkjet head 42a Nozzle surface 44 Nozzle protector (holding parts, nozzle guide)
55 Nozzle 63 Back side slide surface 64 Front side slide surface 65, 66 Stopping piece (stopping member)
68 Convex part 69 Convex part 70 Control part 103 Inkjet printer (image forming apparatus)
113 Image recording unit (droplet discharge device)
116 Wiper blade 120 Carriage 120b Holding part 169 Protruding part 170 Control part 190 Convex part 191 Convex part E Expressing area W Wiping area I Ink collecting area

Claims (9)

An inkjet head having a nozzle surface on which nozzle groups for ejecting ink are formed;
A holding part arranged around the nozzle surface, and a holding part that holds the inkjet head and the holding part and forms an exposed area that is exposed downward together with the nozzle surface and the holding part, A droplet discharge device including a carriage configured to be capable of reciprocating in the scanning direction;
A pair of recording media which are arranged apart from each other in the transport direction intersecting the scanning direction so as to sandwich the exposed area and which should land the ink ejected from the nozzle group in the transport direction below the droplet discharge device. A feed roller,
A wiper that is provided below the droplet discharge device and moves relative to the nozzle surface in a predetermined wiping direction to sweep out ink adhering to the nozzle surface;
The exposed area includes a wiping area that is wiped by the wiper, and an ink reservoir area in which the ink swept out of the wiping area is accumulated.
The image forming apparatus, wherein the holding portion is provided with a convex portion that is disposed between the pair of feed rollers and has a tip that extends downward from the lowermost surface of the exposed region and protrudes. .   The image forming apparatus according to claim 1, wherein the convex portion is provided on at least one side of the holding portion in the transport direction. Of the edges that define the wiping area, at least an edge extending in the wiping direction is located in the exposed area,
3. The image forming apparatus according to claim 1, wherein the ink reservoir area is formed so as to extend along an edge extending in the wiping direction at least in the exposed area. 4.   The image forming apparatus according to claim 1, wherein the wiping area includes at least the entire area of the nozzle surface. The holding portion has an outer wall that surrounds and houses the holding component and the inkjet head,
The image forming apparatus according to claim 1, wherein the convex portion is provided integrally with the outer wall. A pair of guide rails arranged apart in the transport direction and extending in the scanning direction;
The carriage is a pair of slides that are located above the exposed area and spaced apart in the transport direction so as to sandwich the exposed area and are slidably mounted on each of the pair of guide rails A surface and a pair of restraining members disposed below each of the pair of guide rails,
The pair of restraining members restricts upward relative displacement of the carriage with respect to the pair of guide rails,
The image forming apparatus according to claim 1, wherein the convex portion is provided on at least one of the pair of restraining members. The holding part includes a nozzle guide that protects the nozzle surface;
The image forming apparatus according to claim 1, wherein the nozzle guide protrudes downward from the nozzle surface and the holding portion in the exposed area.   The image forming apparatus according to claim 2, wherein the convex portion is provided on an upstream side of the holding portion in the transport direction.   The image forming apparatus according to claim 2, wherein the convex portion is provided on a downstream side of the holding portion in the transport direction.

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