JP2009083352A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a holding surface from being stained while maintaining a striking precision of ink. <P>SOLUTION: The inkjet printer 1 includes a holding mechanism 41 which holds a paper P sent out from a paper feeding part 15, a conveyance mechanism 51 with conveyance belts 58 and 59 which convey the paper P onto the holding surface 46b, a solenoid which moves the conveyance belts 58 and 59, an inkjet head 2 which ejects the ink to the held paper P, a head moving mechanism 70 which moves the inkjet head 2 in a subscan direction, and a controller 90 which controls their actions. The controller 90 moves the conveyance belts 58 and 59 to a conveyance position by driving the solenoid when the paper P is to be conveyed onto the holding surface 46b. Moreover, the controller 90 moves the conveyance belts 58 and 59 from the conveyance position to a retreat position by driving the solenoid after the paper P is conveyed onto the holding surface 46b and before printing is carried out to the paper P. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inkjet recording apparatus that prints an image on a recording medium.

  Patent Document 1 includes a first transport unit having a transport belt for transporting cut paper, and a line head assembly that discharges ink to the cut paper while moving in parallel with the transport direction of the cut paper. A line-type inkjet printer is described. In this line type ink jet printer, the cut sheet is conveyed to the image recording position by the conveyance belt, and the line head assembly discharges ink while moving in parallel with the conveyance direction with respect to the cut sheet held at the position. Then, an image is formed on cut paper.

  Patent Document 2 discloses an inkjet head that ejects ink onto paper, a platen that holds the paper, a paper feed roller that transports the paper sent from the paper storage unit onto the platen, and transports the paper from the platen. An ink jet recording apparatus including a paper discharge roller that discharges downstream in the direction is described. In this ink jet recording apparatus, after the paper is held by the platen, an image is printed on the paper by ejecting ink from the ink jet head to the paper while moving the platen and the ink jet head in a direction orthogonal to the transport direction. .

JP-A-2005-14445 JP 2007-130777 A

  In the line type ink jet printer described in Patent Document 1, the conveyance by the conveyance belt is stopped, and an image is formed on the cut sheet held on the conveyance belt. The distance between the cut sheet and the line head assembly cannot be kept constant immediately after the conveyance belt has stopped running in the direction perpendicular to the recording surface of the cut sheet due to the effect of flapping when the conveyance belt runs. . Further, the distance varies over the entire cut sheet due to the bending of the conveyor belt. As described above, when printing is performed in a state where the smoothness of the recording surface of the cut sheet is not maintained, the ink landing accuracy is lowered, and the image quality is also lowered.

  On the other hand, in the ink jet recording apparatus described in Patent Document 2, the paper is transported onto the platen although the printing surface of the paper is maintained smooth because the paper is held on a flat platen during printing. When the sheet is discharged and the sheet is discharged from the platen, the sheet is conveyed and discharged in a state where the sheet is pressed onto the platen by the sheet feeding roller and the sheet discharge roller. For this reason, when the printed paper is transported and discharged on the surface of the platen side of the paper, the surface of the platen facing the paper becomes dirty. Further, when the platen becomes dirty, the surface of the newly conveyed paper that faces the platen also becomes dirty.

  Accordingly, an object of the present invention is to provide an ink jet recording apparatus capable of making a holding surface difficult to be stained while maintaining ink landing accuracy.

  An ink jet recording apparatus according to the present invention includes a paper feeding unit that can store a recording medium, and a flat holding member that can hold the recording medium fed from the paper feeding unit and has an opening at a position facing the recording medium. A holding means having a surface, and a rotating body that is arranged so that the peripheral surface can be exposed from the opening, and that conveys the recording medium onto the holding surface by contacting the peripheral surface and the recording medium while rotating. An inkjet head having a plurality of ink ejection openings arranged along a predetermined direction on an ink ejection surface that can face the holding surface, and a head movement that moves the inkjet head in a direction orthogonal to the predetermined direction A mechanism and a transfer position in which the peripheral surface is the same position as the holding surface or a position protruding from the holding surface with respect to a direction perpendicular to the holding surface; and the peripheral surface Between the retracted position where it does not spaced and projecting from the holding surface, and a rotating member moving means for moving the rotating member. The rotating body moving means moves the rotating body to the transport position when transporting the recording medium onto the holding surface, and after transporting the recording medium onto the holding surface, the inkjet head By this, the rotating body is moved from the transport position to the retracted position before printing on the recording medium.

  According to this, when printing on the recording medium, the recording medium on the holding surface can be held in a flat state. Therefore, ink landing accuracy can be maintained. In addition, when the recording medium is transported onto the holding surface, the circumferential surface of the rotating body arranged at the transport position is in contact with the surface on the holding surface side of the recording medium and is transmitted to the surface on the holding surface side of the recording medium. The recording medium is conveyed by the conveyed force. Therefore, unlike the technique described in Patent Document 2 in which a sheet is pressed onto a platen and conveyed, the recording medium can be conveyed without being pressed against the holding surface. Therefore, even if the recording medium on which the printing is performed on the surface on the holding surface side of the recording medium is transported, the holding surface is hardly stained.

  In the present invention, it is preferable that a plurality of the openings are formed in the holding surface, and a plurality of the rotating bodies are provided so that the peripheral surface can be exposed from the openings. Thereby, a recording medium can be more reliably conveyed by a some rotary body.

  Further, in the present invention, the conveying means includes a pair of rollers, and a conveying belt that spans between the pair of rollers and has a conveying surface parallel to the holding surface, and the rotating body includes A conveyor belt is preferred. Thereby, the recording medium can be more reliably transported on the transport surface.

  In the present invention, it is preferable that the holding unit releases the holding of the recording medium when the recording medium is being conveyed by the rotating body. Thereby, when the recording medium is conveyed by the rotating body, the holding force by the holding means does not act on the recording medium. Therefore, the recording medium can be reliably conveyed, and even if the recording medium on which the printing is performed on the surface on the holding surface side of the recording medium is conveyed, the holding surface is less likely to become dirty.

  In the invention, the predetermined direction is further parallel to a conveyance direction in which the recording medium is conveyed by the rotating body, and further includes a detection unit that detects a recording medium that can move together with the inkjet head by the head moving mechanism. It is preferable. Thereby, when the inkjet head is moved when printing on the recording medium, the detecting means for detecting the end portion in the width direction orthogonal to the conveying direction of the recording medium can be simplified.

  In the present invention, the image forming apparatus may further include positioning means capable of selectively taking a positioning enabling state and a releasing state thereof capable of positioning the front end in the conveyance direction of the recording medium on the holding surface. preferable. Thereby, the front end position of the recording medium can be reliably positioned at a predetermined position on the holding surface.

  In the present invention, it is preferable that a paper discharge unit is provided on the downstream side in the transport direction in which the recording medium is transported by the rotating body. As a result, the direction in which the recording medium is conveyed from the paper feed unit onto the holding surface and the direction in which the recording medium is conveyed from the holding surface to the paper discharge unit are the same, so that the paper can be discharged with a simple configuration.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic plan view of an inkjet printer according to an embodiment of the present invention. FIG. 2 is a schematic side view of an inkjet printer according to an embodiment of the present invention.

  The ink jet printer (ink jet recording apparatus) 1 is a color ink jet printer having four ink jet heads 2. The ink jet printer 1 is provided with a paper feed mechanism 11 at the top in FIG. 1 and a paper discharge unit 10 at the bottom in FIG. Between the paper feed mechanism 11 and the paper discharge unit 10, the paper (recording medium) P sent out from the paper feed mechanism 11 is transported in a transport direction A (main scanning direction) from the upper side to the lower side in FIG. A transport device 40 is provided. Further, the printer 1 includes a head moving mechanism 70 that moves the inkjet head 2 in the left-right direction in FIG. 1, that is, a direction orthogonal to the conveyance direction A (sub-scanning direction), four inkjet heads 2, a conveyance device 40, and A control device 90 that controls the operation of the head moving mechanism 70 and the like is provided. The main scanning direction is a direction parallel to the transport direction A, and the sub-scanning direction is a direction orthogonal to the main scanning direction and along a horizontal plane (left and right direction in FIG. 1).

  As shown in FIG. 2, the paper feed mechanism 11 has a box-shaped paper feed portion 15 that opens upward so that a plurality of paper sheets P can be stored in a stacked state in the vertical direction. Further, the paper feeding mechanism 11 includes a pickup roller 12 disposed so as to be in contact with the uppermost paper P among the plurality of papers P stored in the paper feeding unit 15, a plurality of rollers 13 coaxially connected, and A pair of paper feed rollers 17 including a long roller 14 paired with these rollers 13 is provided. The pair of paper feed rollers 17 is disposed between the paper feed unit 15 and the conveyance leave 40 and conveys the paper P sent out along the conveyance direction A by the pickup roller 12 in the same conveyance direction A. The pickup roller 12 and the paper feed roller pair 17 are rotated by a drive motor (not shown) controlled by the control device 90.

  In this configuration, the paper P is sent out to the transport device 40 by the pickup roller 12 and the paper feed roller pair 17 rotating under the control of the control device 90.

  FIG. 3 is a plan view showing the inside of the housing 42 included in the transport apparatus 40 shown in FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 3, and (a) is a diagram showing a state in which the conveyance surface of the conveyance belt and the upper end of the stopper are arranged at positions protruding from the holding surface. (B) is a figure which shows the state arrange | positioned in the position which the upper end of a conveyance surface and a stopper does not protrude from a holding surface.

  As shown in FIGS. 1 to 3, the transport device 40 includes a holding mechanism (holding unit) 41 that holds the paper P sent out from the paper feeding unit 15. The holding mechanism 41 has a rectangular parallelepiped housing 42 having a space inside. The housing 42 is formed with four partition walls 43a to 43d that partition the internal space into five spaces 42a to 42e. Three fans 45a to 45c disposed in the three spaces 42a, 42c, and 42e are fixed to the bottom plate 44 of the housing 42, respectively. The three fans 45a to 45c are driven by the control of the control device 90, and discharge the air in the spaces 42a, 42c, and 42e from discharge ports (not shown) formed in the bottom plate 44. As shown in FIGS. 1 and 4, a plurality of through holes 46 a are formed in regions facing the spaces 42 a, 42 c, 42 e of the top plate 46 of the housing 42. In addition, two openings 46 c are formed in areas facing the spaces 42 b and 42 d of the top plate 46 of the housing 42 and the paper P.

  In this configuration, when the paper P is arranged on the flat holding surface (upper surface in FIG. 4) 46b of the top plate 46, the three fans 45a to 45c are driven by the control of the control device 90, so that the external Are sucked from the plurality of through holes 46a, and the paper P is adsorbed to the holding surface 46b in a flat state. When the driving of the three fans 45a to 45c is stopped, the suction of the paper P on the holding surface 46b is released.

  In the housing 42, as shown in FIG. 3, a transport mechanism (transport means) 51 is provided. The transport mechanism 51 includes two shafts 52 and 53, two pairs of rollers 54 to 57, and two pairs of rollers 54 to 57 that are arranged so as to penetrate the four partition walls 43a to 43d in the sub-scanning direction. It includes two conveyor belts (rotators) 58 and 59 that are stretched over, and a drive motor 60 that rotates a shaft 53.

  Each pair of rollers 54 to 57 is fixed to shafts 52 and 53, respectively. The pair of rollers 54 and 55 and the conveyor belt 58 are disposed in the space 42b. The pair of rollers 56 and 57 and the conveyor belt 59 are disposed in the space 42d. Further, the conveying surfaces 58a and 59a, which are the surfaces (circumferential surfaces) of the conveying belts 58 and 59, are arranged so as to be exposed from the opening 46c in a state parallel to the holding surface 46b, as shown in FIGS. ing.

  The two shafts 52 and 53 are rotatably supported at both ends by two support plates 61a and 61b that are long in the main scanning direction. As shown in FIG. 4, the two shafts 52 and 53 are passed through long holes 62 formed in two in each of the four partition walls 43 a to 43 d. The long hole 62 extends in the vertical direction. In addition, two solenoids 63 a and 63 b are fixed to the bottom plate 44. The solenoids 63a and 63b are disposed in the spaces 42a and 42e, and the cylinders of the solenoids 63a and 63b are fixed to the center of the lower ends of the corresponding support plates 61a and 61b. Solenoids 63 a and 63 b are driven under the control of the control device 90. The solenoids 63a and 63b and the control device 90 constitute rotating body moving means.

  With this configuration, when the solenoids 63a and 63b are driven by the control of the control device 90 and the cylinders are extended as shown in FIG. 4A, the conveying surfaces 58a and 59a of the conveying belts 58 and 59 are connected to the holding surface 46b. It is arranged at a transport position which is a position slightly protruding from the holding surface 46b in a parallel state. On the other hand, as shown in FIG. 4B, when the cylinder is contracted, the conveying surfaces 58a and 59a are spaced apart from the holding surface 46b and are disposed at a retracted position where they do not protrude. In the transport position in the present embodiment, the transport surfaces 58a and 59a of the transport belts 58 and 59 are positions protruding upward from the holding surface 46b, but the sheet P and the transport surfaces 58a and 59a on the holding surface 46b Are in contact with each other and the conveying force due to the traveling of the conveying belts 58 and 59 can be transmitted to the sheet P, the conveying position is defined as the conveying surfaces 58a and 59a positioned at the same height level as the holding surface 46b. Also good.

  As shown in FIG. 3, an L-shaped flange 64 is fixed to the support plate 61 a, and the drive motor 60 is fixed to the flange 64. A gear 65 is fixed to the drive shaft of the drive motor 60 and meshes with a gear 66 fixed to the end of the shaft 53. The drive motor 60 is driven by the control of the control device 90, and the gear 65 rotates.

  In this configuration, the drive motor 60 is driven by the control of the control device 90, and the gear 65 rotates in a predetermined direction, so that the gear 66, the shaft 53, and the rollers 53 and 55 rotate in a direction opposite to the predetermined direction. The conveyance belts 58 and 59 travel (rotate) so that the conveyance surfaces 58a and 59a move along the conveyance direction A by the rotation of the rollers 53 and 55. The entire paper P sent out from the paper supply unit 15 by the travel of the transport belts 58 and 59 is transported onto the holding surface 46b. Further, the transport belts 58 and 59 transport the paper P from the holding surface 46b along the transport direction A to the paper discharge unit 10 side. When the paper P is transported, the transport belts 58 and 59 are disposed at the transport position.

  Further, on the downstream side surface in the transport direction A of the housing 42, as shown in FIG. 4, the holding surface 46 b holds the stopper 28 that is positioned by contacting the front end 7 of the paper P, and the upper end of the stopper 28. A solenoid 29 for moving the stopper 28 is provided so that a positionable state protruding upward from the surface 46b and a released state where the upper end of the stopper 28 does not protrude from the holding surface 46b can be selectively taken. The stopper 28 and the solenoid 29 constitute a positioning means for the paper P on the holding surface 46b. The solenoid 29 is controlled by the control device 90.

  The stopper 28 is a long plate-like member extending in the sub-scanning direction. At the center of the lower end of the stopper 28, the tip of the cylinder 29a of the solenoid 29 is fixed. With this configuration, when the solenoid 29 is driven by the control device 90 and the cylinder 29a extends upward as shown in FIG. 4A, the stopper 28 can be positioned, and when the cylinder 29a contracts, the stopper 28 is released. It will be in a state (refer to Drawing 4 (b)).

  Further, since the stopper 28 is made of a long plate-like member, the positioning of the front end 7 of the paper P and the skew of the paper P can be corrected. To correct this skew, the front end 7 slightly inclined with respect to the sub-scanning direction is provided with the stopper 28 even if the paper P sent out from the paper supply unit 15 and transported is tilted during the transport. , The extending direction of the front end 7 is corrected to be parallel to the sub-scanning direction, and the extending direction of both ends in the width direction (sub-scanning direction) of the paper P is corrected to be parallel to the transport direction A. is there.

  The transport apparatus 40 has two transport tables 21 and 22 arranged on the upstream side and the downstream side of the housing 42 in the transport direction A. As shown in FIGS. 1 and 2, the transport tables 21 and 22 are both plate-like members having a rectangular planar shape, and upper surfaces thereof are transport surfaces 21 a and 22 a parallel to the holding surface 46 b. Moreover, these conveyance surfaces 21a and 22a are arrange | positioned at the same height level as the holding surface 46b. Further, a through-hole 21b connected to a reversing path 36b described later is formed in the transport table 21.

  The transport apparatus 40 has a double-feed roller pair 30 disposed between the housing 42 and the paper discharge unit 10 in the transport direction A. The both-feed roller pair 30 includes a plurality of rollers 31 that are coaxially connected and a long roller 32 that is paired with the rollers 31. The pair of feed rollers 30 is either in the transport direction A or in the direction opposite to the transport direction A (hereinafter referred to as the reverse transport direction B) by a drive motor (not shown) controlled by the control device 90. Rotate to selectively transport.

  With this configuration, between the paper feed roller pair 17 and the both feed roller pair 30, as shown in FIG. A main path 36a that transports along the transport direction A while facing the ink ejection surface 2a of the head 2 is formed (see FIG. 2). In the present embodiment, the main path 36a extends in the horizontal direction.

  Further, as shown in FIG. 2, with respect to the transport direction A, the direction of the paper P fed in the reverse transport direction B by the both feed roller pair 30 is switched downward between the both feed roller pair 30 and the transport base 22. A switching guide 35 is arranged. The switching guide 35 is configured to be swingable about an axis that is parallel to the surface of the paper P that is transported along the main path 36 a and that is orthogonal to the transport direction A. Then, the switching guide 35 is swung around the axis by a drive device (not shown) controlled by the control device 90 so that it does not intersect the main path 36a (state shown by a solid line in FIG. 2). Can be selectively taken (a state indicated by a broken line in FIG. 1). Further, the switching guide 35 has a curved guide surface 35a, and the sheet P fed in the reverse transport direction B by the both-feed roller pair 30 is the guide surface 35a of the switching guide 35 in a state of intersecting the main path 36a. And is guided downward.

  Further, the transport device 40 guides the paper P whose transport direction has been switched downward by the switching guide 35 downward, and the re-feeding guide 37a transports the paper P guided by the lower guide 37a in the reverse transport direction B. A transport mechanism 38, a refeed roller pair 39 that transports the paper P transported by the retransport mechanism 38 upward while sandwiching it, and sends it onto the transport surface 21a of the transport base 21, and a refeed roller pair 39. And an ascending guide 37b for guiding the conveyed paper P. The re-transport mechanism 38 is driven by the control device 90 and transports the paper P in the reverse transport direction B. The refeed roller pair 39 is rotated by a drive motor (not shown) controlled by the controller 90. Further, the upper end of the rising guide 37b is fixed to the transport table 21 so that the paper P guided by the rising guide 37b is transported into the through-hole 21b.

  With such a configuration, the printer 1 is formed with a reverse path 36b extending below the main path 36a from between the transport table 22 and the pair of feed rollers 30 to the penetrating portion 21b of the transport table 21. Through the reverse path 36b, the paper P sent in the reverse conveyance direction B by the pair of feed rollers 30 is sent again to the main path 36a from the penetrating portion 21b with the front and back sides reversed. In other words, the paper P that has passed through the reversing path 36b enters the main path 36a with the other surface opposite to the upper surface facing upward when the paper P is fed by the pair of paper feed rollers 17. Sent.

  The double feed roller pair 30 is a so-called switchback roller pair that reverses the transport direction of the paper P from the transport direction A to the reverse transport direction B and switches the transport path of the paper P from the main path 36a to the reverse path 36b. It has the function of Further, the pair of feed rollers 30 also has a function as a so-called discharge roller pair that discharges the paper P to the paper discharge unit 10.

  The four inkjet heads 2 correspond to inks of four colors (magenta, yellow, cyan, and black) and have a rectangular shape that is long in the main scanning direction in plan view as shown in FIG. Yes. The four inkjet heads 2 are arranged in the sub-scanning direction and fixed to the frame-shaped frame 3 to constitute one head unit 4.

  The surface (that is, the ink ejection surface 2a) that can face the holding surface 46b of the inkjet head 2 is configured by two nozzle rows in which a plurality of nozzles (ink ejection ports) 5 are arranged along the main scanning direction. Ink discharge region 6 is formed. As shown in FIG. 2, the ink ejection surface 2a and the lower surface of the frame 3 are formed on substantially the same plane level. Further, in the inkjet head 2, an actuator (not shown) provided therein is driven under the control of the control device 90, and ink is ejected from the nozzle 5.

  As shown in FIG. 1, the ink discharge region 6 is formed on the ink discharge surface 2 a so that the lower end thereof overlaps the front end 7 of the paper P positioned by the stopper 28 along the sub-scanning direction. Therefore, an image can be printed at a desired position on the paper P in the main scanning direction. In the present embodiment, the lower end of the ink discharge region 6 overlaps the front end 7 along the transport direction B, but the front end 7 may overlap a portion other than the lower end of the ink discharge region 6. That is, if any part of the ink discharge region 6 and the front end 7 overlap, the above-described effect can be obtained.

  Two photosensors (detecting means) 85 and 86 connected to the control device 90 are fixed at the center of each end of the frame 3 in the sub-scanning direction. A light-emitting portion and a light-receiving portion are provided on a surface that can face the holding surface 46b of the photosensors 85 and 86, that is, the detection surface 85a. As a result, as described later, when the head unit 4 moves from the first standby position to the right in FIG. 1, one end (left end in FIG. 1) of the paper P adsorbed on the holding surface 46b is detected. It becomes possible to do. On the other hand, when the head unit 4 moves from the second standby position to the left in FIG. 1, it is possible to detect the other end (the right end in FIG. 1) of the paper P in the sub-scanning direction. Therefore, the timing at which the paper P and the ink ejection surface 2a face each other can be known, and an image can be printed at a desired position on the paper P in the direction orthogonal to the transport direction A (sub-scanning direction).

  As shown in FIG. 1, the head moving mechanism 70 is separated from the two guide rails 71 and 72, which are disposed so as to penetrate both ends of the frame 3 in the main scanning direction in the sub scanning direction. A pair of rollers 73 and 74 and a belt 75 spanning the rollers 73 and 74 are provided. The roller 74 is rotated by a drive motor (not shown) controlled by the control device 90, and the roller 73 is a driven roller and is rotatably supported. A protruding portion 76 that protrudes from the downstream side surface in the transport direction A of the frame 3 is fixed to the belt 75.

  In this configuration, when the roller 74 rotates in a predetermined direction under the control of the control device 90, the belt 75 travels, and the head unit 4 and the photosensors 85 and 86 are positioned so as not to face the holding surface 46 b, and are shown in FIG. 1 moves to the right (in the direction parallel to the sub-scanning direction) in FIG. 1 from the first standby position separated to the left in the middle of FIG. 1 and passes through the region facing the holding surface 46b. Move to a second standby position (a position indicated by a two-dot chain line in FIG. 1). On the other hand, under the control of the control device 90, when the roller 74 rotates in the direction opposite to the predetermined direction, the head unit 4 and the photo sensors 85 and 86 return from the second standby position to the first standby position.

  Next, a printing operation when printing an image on the paper P will be described below. When printing on both sides of the paper P, the control device 90 controls to feed the paper P from the paper feed unit 15 by the pickup roller 12 and the paper feed roller pair 17 and on the holding surface 46b by the running of the conveyor belts 58 and 59. Transport to. At this time, the cylinders of the solenoids 63a and 63b are extended by the control of the control device 90, and the conveying surfaces 58a and 59a are disposed at the conveying position slightly protruding from the holding surface 46b (see FIG. 4A). . For this reason, the conveyance surfaces 58a and 59a and the surface on the holding surface 46b side of the sheet P are in contact with each other, and the entire sheet P is conveyed onto the holding surface 46b by the traveling of the conveyance belts 58 and 59. At this time, as shown in FIG. 4A, the cylinder 29a of the solenoid 29 is extended by the control of the control device 90, and the upper end of the stopper 28 projects from the holding surface 46b. Yes. Therefore, the front end 7 of the paper P conveyed on the holding surface 46b comes into contact with the upper end of the stopper 28, and the paper P is positioned on the holding surface 46b and the skew is corrected.

  Next, under the control of the control device 90, the cylinders of the solenoids 63a and 63b are contracted, and the conveying surfaces 58a and 59a are disposed at a retracted position where they do not protrude from the holding surface 46b (see FIG. 4B). Then, the three fans 45a to 45c are driven by the control of the control device 90, and the sheet P is adsorbed to the holding surface 46b. As described above, after the transport surfaces 58a and 59a are arranged at the retracted position, the paper P is adsorbed to the holding surface 46b, so that the paper P is held on the holding surface 46b in a flat state.

  Next, after the cylinder 29a of the solenoid 29 is contracted by the control of the control device 90 and the upper end of the stopper 28 is released so as not to protrude from the holding surface 46b, the roller 74 is moved in a predetermined direction by the control of the control device 90. The head unit 4 and the two photosensors 85 and 86 are moved from the first standby position to the second standby position by being rotated. At this time, the left end of the paper P in FIG. 1 is detected by the photo sensor 85, and the control device 90 controls the ink jet head 2 according to the detection result of the photo sensor 85, so that the ink ejection area 6 faces the paper P. Ink is ejected in order from the nozzles 5 of the inkjet head 2 on the downstream side in the movement direction of the head unit 4 at an appropriate timing when passing through the region, and an image is printed at a desired position on the paper P. Since the head unit 4 is moved after the stopper 28 is released, the head unit 4 and the stopper 28 do not come into contact with each other.

  Next, after the head unit 4 and the two photosensors 85 and 86 reach the second standby position, the control of the control device 90 stops the driving of the fans 45a to 45c and the cylinders of the solenoids 63a and 63b. The conveyor belts 58 and 59 are arranged at the transport position. Then, under the control of the control device 90, the transport belts 58 and 59 and the both-feed roller pair 30 are rotated so that the paper P is transported in the transport direction A.

  Next, when the trailing edge of the paper P is disposed between the pair of feed rollers 30 and the switching guide 35, the control of the control device 90 stops the travel of the transport belts 58 and 59 and the paper P The feed roller pair 30 is rotated in the reverse direction so as to feed in the reverse conveyance direction B. At this time, under the control of the control device 90, the switching guide 35 is swung from a state where it does not intersect with the main path 36a. As a result, the rear end of the paper P (the front end in the reverse transport direction B) comes into contact with the guide surface 35a, and the paper P is guided downward and guided to the lowering guide 37a. Then, under the control of the control device 90, the re-conveying mechanism 38 and the re-feed roller pair 39 are driven, and the paper P is conveyed in the reverse conveying direction B and ascends in the ascending guide 37b, from the reverse path 36b to the main path 36a. Be transported.

  Next, when the paper P whose front and back are reversed in the reversing path 36b, that is, the sheet P whose image is printed on the holding surface 46b side is conveyed to the main path 36a, by the control of the control device 90, The cylinders of the solenoids 63a and 63b are extended, and the entire sheet P is transported onto the holding surface 46b by the travel of the transport belts 58 and 59. At this time, the stopper 28 can be positioned by the control of the control device 90, and the sheet P is positioned and the skew is corrected on the holding surface 46b.

  Next, under the control of the control device 90, the transport surfaces 58a and 59a are arranged at the retracted position where they do not protrude from the holding surface 46b, the three fans 45a to 45c are driven, and the paper P is attracted to the holding surface 46b.

  Next, after the stopper 28 is released by the control of the control device 90, the roller 74 is rotated in the direction opposite to the predetermined direction, and the head unit 4 and the two photosensors 85, 86 are moved from the second standby position. It is moved to the first standby position. At this time, the right edge of the paper P in FIG. 1 is detected by the photosensor 86, and the control device 90 controls the ink jet head 2 according to the detection result of the photosensor 86, so that the ink ejection area 6 faces the paper P. Ink is ejected in order from the nozzles 5 of the inkjet head 2 on the downstream side in the movement direction of the head unit 4 at an appropriate timing when passing through the region, and an image is printed at a desired position on the paper P.

  Next, after the head unit 4 and the two photosensors 85 and 86 reach the first standby position, the control of the control device 90 stops the driving of the fans 45a to 45c and the cylinders of the solenoids 63a and 63b. The conveyor belts 58 and 59 are arranged at the transport position. Then, under the control of the control device 90, the transport belts 58 and 59 and the both-feed roller pair 30 are rotated so that the paper P is transported in the transport direction A. In this way, the paper P that has been printed on both sides is discharged to the paper discharge unit 10, and the double-sided printing operation ends. When printing is performed on one side of the paper P, after printing is performed on one side of the paper P, the paper P is not conveyed to the reversing path 36b, but is directly fed to the paper discharge unit 10 by the pair of feed rollers 30. What is necessary is just to discharge P.

  As described above, according to the inkjet printer 1 of the present embodiment, when printing is performed on the paper P (that is, the head unit 4 is moved from the first standby position to the second standby position and in the opposite direction). Sometimes, it becomes possible to hold the paper P on the holding surface 46b in a flat state. Therefore, the separation distance between the ink ejection surface 2a and the paper P is constant over the entire paper P, and the landing accuracy of the ink ejected from the nozzle 5 can be maintained. In addition, when the paper P is transported onto the holding surface 46b, the transport surfaces 58a and 59a of the transport belts 58 and 59 disposed at the transport position and the back surface of the paper P (the surface on the holding surface side) are in contact with each other. The paper P is transported by the transport force transmitted to the back surface of the paper P. Therefore, unlike the technique described in Patent Document 2 in which the paper P is pressed and conveyed from above to the holding surface, the paper P can be conveyed without being pressed against the holding surface, and double-sided printing is performed. Even if the paper P printed on the surface on the holding surface 46b side of the paper P is conveyed onto the holding surface 46b, the holding surface 46b is less likely to become dirty. As described above, when the holding surface 46b is less likely to become dirty, even if the newly conveyed paper P comes into contact with the holding surface 46b, the stain does not move.

  Further, since the two conveyor belts 58 and 59 are provided, the paper P can be more reliably conveyed. Further, since the paper P is transported by the transport surfaces 58a and 59a of the transport belts 58 and 59, the paper P can be transported more reliably. Further, when the paper P is transported by the transport belts 58 and 59, the driving of the fans 45a, 45b and 45c is stopped, and the suction force, that is, the holding force does not act on the paper P. Can be reliably transported, and even if the paper P printed on the surface on the holding surface side of the paper P is transported, the surface becomes difficult to be transported while being in contact with the holding surface 46b. 46b becomes more difficult to get dirty.

  By having the photosensors 85 and 86 that move together with the head unit 4, when the head unit 4 moves when printing on the paper P, the end of the paper P in the width direction (sub-scanning direction) can be simplified. Can be detected by configuration. Further, since the positioning means including the stopper 28 and the solenoid 29 is provided, the position of the front end 7 of the paper P can be reliably positioned at a predetermined position on the holding surface 46b. Further, since the paper discharge unit 10 is provided on the downstream side in the transport direction A, the paper P is transported from the paper supply unit 15 onto the holding surface 46b and the paper P is discharged from the holding surface 46b. 10, the paper P can be discharged with a simple configuration.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, in the above-described embodiment, the inkjet head 2 is moved in parallel to the sub-scanning direction orthogonal to the transport direction A, but the image may be printed on the paper P by moving in parallel to the transport direction A. . Further, one or three or more conveyance belts (rotators) for conveying the entire sheet P on the holding surface 46b and conveying the sheet P from the holding surface 46b may be provided. Moreover, it may replace with the conveyance belts 58 and 59 and may have one or more rollers as a rotating body. In this case, it is preferable that the peripheral surface of the roller can be exposed from the opening 46c.

  Further, the photosensors 85 and 86 may be arranged anywhere as long as the end of the paper P in the width direction can be detected before the ink ejection surface 2a and the paper P face each other. Further, only one of the photosensors 85 and 86 may be provided, or the photosensor, that is, the detection unit may not be provided. Further, the positioning means composed of the stopper 28 and the solenoid 29 may not be provided. Further, the paper discharge unit 10 may be provided at a position other than the downstream side in the transport direction A from the holding mechanism 41.

  The inkjet printer 1 of the present embodiment has a configuration such as the reverse path 36b and the double feed roller pair 30 that enable double-sided printing, but is a printer that has a configuration that can simply print on one side. There may be. Even in this case, when the paper P on which the printing is performed on the surface on the holding surface side is transported, the holding surface is less likely to become dirty as described above. Further, the holding mechanism 41 in the present embodiment holds the paper P by the holding surface 46b by air suction for sucking outside air from the plurality of through holes 46a, but an electrode is built in the DC, and a DC voltage is applied to the electrode. A holding mechanism using a platen that is charged by supplying itself may be used. That is, the configuration is not particularly limited as long as the paper P can be held by the holding surface.

1 is a schematic plan view of an inkjet printer according to an embodiment of the present invention. 1 is a schematic side view of an inkjet printer according to an embodiment of the present invention. It is a top view which shows the inside of the housing | casing contained in the conveying apparatus shown in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 3, and (a) is a diagram illustrating a state in which the conveyance surface of the conveyance belt and the upper end of the stopper are arranged at positions protruding from the holding surface; FIG. 6 is a view showing a state where the conveying surface and the upper end of the stopper are arranged at positions where they do not protrude from the holding surface.

Explanation of symbols

1 Inkjet printer (inkjet recording device)
2 Inkjet head 2a Ink ejection surface 5 Nozzle (ink ejection port)
6 Ink Ejection Area 7 Front End 10 Paper Discharge Unit 15 Paper Feed Unit 28 Stopper 29 Solenoid 41 Holding Mechanism (Holding Unit)
46b Holding surface 46c Opening 51 Transport mechanism (transport means)
54-57 Roller 58, 59 Conveyor belt (Rotating body)
58a, 59a Conveying surface (circumferential surface)
63a, 63b Solenoid 70 Moving mechanism 85, 86 Photo sensor (detection means)
90 Control device

Claims (7)

A paper feed unit capable of storing a recording medium;
Holding means having a flat holding surface capable of holding the recording medium sent out from the paper feed unit and having an opening formed at a position facing the recording medium;
Conveying means having a rotating body that is arranged so that the peripheral surface can be exposed from the opening and that conveys the recording medium onto the holding surface by contacting the peripheral surface with the recording medium while rotating.
An ink jet head having a plurality of ink ejection openings arranged along a predetermined direction on an ink ejection surface that can face the holding surface;
A head moving mechanism for moving the inkjet head in a direction orthogonal to the predetermined direction;
With respect to a direction perpendicular to the holding surface, the circumferential position is the same position as the holding surface or a transfer position where the peripheral surface protrudes from the holding surface, and the retraction is separated from the holding surface and does not protrude. A rotating body moving means for moving the rotating body between the positions,
The rotating body moving means moves the rotating body to the transport position when transporting the recording medium onto the holding surface, and after the recording medium is transported onto the holding surface, the recording is performed by the inkjet head. An inkjet recording apparatus, wherein the rotating body is moved from the transport position to the retracted position before printing on a medium. A plurality of the openings are formed in the holding surface,
The inkjet recording apparatus according to claim 1, wherein a plurality of the rotating bodies are provided so that the peripheral surfaces can be exposed from the openings. The transport means includes a pair of rollers, and a transport belt that spans the pair of rollers and has a transport surface parallel to the holding surface;
The inkjet recording apparatus according to claim 1, wherein the rotating body is the conveyance belt.   The inkjet recording apparatus according to claim 1, wherein the holding unit releases the holding of the recording medium when the recording medium is being conveyed by the rotating body. The predetermined direction is parallel to a conveyance direction in which the recording medium is conveyed by the rotating body,
5. The inkjet recording apparatus according to claim 1, further comprising a detection unit configured to detect a recording medium that can move together with the inkjet head by the head moving mechanism.   2. A positioning unit capable of selectively taking a position enabling state and a releasing state thereof capable of positioning the front end of the recording medium in the transport direction on the holding surface. The inkjet recording apparatus according to any one of 5.   The inkjet recording apparatus according to claim 1, wherein a paper discharge unit is provided on a downstream side in a conveyance direction in which the recording medium is conveyed by the rotating body.

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