JP2016064880A - Ink jet record device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet record device capable of suppressing a sheet which is curled due to an ink discharged to the sheet, from contacting a record head.SOLUTION: An ink jet record device 1 of the invention forms an image on a sheet S by an image formation part 80. The ink jet record device 1 comprises: a first transport path 60 on which the sheet S on which the image is formed, is transported; and a second transport path 70 which is branched from the first transport path 60 and on which the sheet S is transported again to the image formation part 80. The ink jet record device 1 further comprises a control part 50 and a storage part 10. The storage part 10 is disposed on the second transport path 70 and stores the sheet S. The storage part 10 includes a guide plate 21 and a correction plate 32. The guide plate 21 mounts the sheet S thereon. The correction plate 32 presses the sheet S against the guide plate 21. The control part 50 changes time when the correction plate 32 presses the sheet S against the guide plate 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ink jet recording apparatus.

  A general inkjet recording apparatus forms an image on a sheet by ejecting ink from a plurality of nozzles provided in a recording head. When the inkjet recording apparatus uses water-based ink, moisture permeates and the fibers swell on the first surface of the sheet where the image is formed. Accordingly, the area of the first surface of the sheet is expanded. As a result, the area of the first surface of the sheet may be larger than the area of the second surface of the sheet where no image is formed. Due to the difference between the area of the first surface of the sheet and the area of the second surface of the sheet, the first surface of the sheet curls in a convex shape.

  In view of this, the image forming apparatus described in Patent Document 1 causes the recording medium to wait until the recording medium is less likely to curl in a state where a part of the recording medium on which image formation by the recording head has been completed is restrained from above and below. . Specifically, the recording medium on which image formation has been completed is constrained by a plurality of conveying rollers for conveying the recording medium and a plurality of spur rollers arranged to face the plurality of conveying rollers. Thereafter, the recording medium is discharged.

JP 2006-082546 A

  However, in the image forming apparatus described in Patent Document 1, the end of the recording medium is not constrained. Therefore, in an image forming apparatus that forms an image on both sides of a sheet, the end portion of the sheet when re-conveyed immediately below the recording head may curl toward the recording head. As a result, the sheet may come into contact with the recording head. When the sheet contacts the recording head, the sheet may be contaminated or the edge of the sheet may be broken.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording apparatus capable of suppressing the sheet curled by the ink discharged onto the sheet from coming into contact with the recording head.

  According to the present invention, the ink jet recording apparatus forms an image on a sheet by the image forming unit. In the ink jet recording apparatus, a first conveyance path for conveying the sheet on which the image is formed and a second conveyance path branched from the first conveyance path and re-conveyed to the image forming unit are formed. The The ink jet recording apparatus includes a control unit and a storage unit. The storage unit is provided in the second conveyance path and stores the sheet. The storage unit includes a guide plate and a correction plate. The sheets are stacked on the guide plate. The correction plate presses the sheet toward the guide plate. The control unit changes a time during which the correction plate presses the sheet toward the guide plate.

  According to the present invention, the sheet curled by the ink discharged onto the sheet can be prevented from coming into contact with the recording head.

It is sectional drawing which shows the inkjet recording device which concerns on embodiment of this invention. It is a figure which shows the storage part of the inkjet recording device which concerns on embodiment of this invention. It is a figure which shows operation | movement of the correction board of the inkjet recording device which concerns on embodiment of this invention. It is a figure which shows the correction | amendment part of the inkjet recording device which concerns on embodiment of this invention from upper direction. (A) It is a figure which shows the feeding unit located in the standby position of the inkjet recording device which concerns on embodiment of this invention. (B) It is a figure which shows the feed unit located in the feed position of the inkjet recording device which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof is not repeated. In the present embodiment, the X axis and the Y axis are parallel to the horizontal plane, and the Z axis is parallel to the vertical line.

  With reference to FIG. 1, an ink jet recording apparatus 1 according to the present embodiment will be described. FIG. 1 shows an ink jet recording apparatus 1. In the ink jet recording apparatus 1, a first transport path 60 and a second transport path 70 are formed. The ink jet recording apparatus 1 includes a storage unit 10, a control unit 50, a sensor 71, an image forming unit 80, a housing 100, a feeding unit 200, a transport unit 300, and a discharge tray 400. The ink jet recording apparatus 1 forms an image on the sheet S by the image forming unit 80. The sheet S is, for example, plain paper, recycled paper, thin paper, thick paper, or an OHP (Overhead Projector) sheet.

  The feeding unit 200 includes a feeding cassette 201 and a feeding roller 203. The feeding cassette 201 is detachably attached to the housing 100 and is disposed below the inside of the housing 100. A plurality of sheets S are stored in the feeding cassette 201. The feeding roller 203 is disposed above one end side of the feeding cassette 201. The feeding roller 203 feeds the sheet S stored in the feeding cassette 201 to the conveyance unit 300.

  The conveyance unit 300 is disposed on one side of the image forming unit 80. The conveyance unit 300 includes a registration roller pair 301. The conveyance unit 300 conveys the sheet S conveyed from the feeding cassette 201 to the image forming unit 80. The registration roller pair 301 is provided on the exit side of the transport unit 300. The registration roller pair 301 temporarily waits the sheet S, and then conveys the sheet S to the image forming unit 80 in accordance with the timing at which the image forming unit 80 forms an image on the sheet S.

  The image forming unit 80 forms an image on the sheet S. The image forming unit 80 is disposed above the feeding unit 200. The image forming unit 80 includes a transport mechanism 81 and a recording head 83. The transport mechanism 81 transports the sheet S transported from the transport unit 300 in the transport direction D toward the first transport path 60. The transport mechanism 81 includes an endless transport belt 810 and a suction unit 811. A plurality of through holes (not shown) penetrating the conveying belt 810 in the thickness direction are perforated. When the suction unit 811 is driven, a negative pressure is generated. The negative pressure acts on the sheet S supported on the conveyance surface of the conveyance belt 810 via the plurality of through holes of the conveyance belt 810. Accordingly, the sheet S is conveyed while being sucked by the suction unit 811 on the conveying belt 810.

  The recording head 83 forms an image by discharging aqueous ink onto the sheet S conveyed by the conveyance mechanism 81. The water-based ink contains, for example, a pigment or a dye as a coloring material. The image is formed on the first surface of the sheet S, or the first surface and the second surface of the sheet S. The first surface is a surface of the sheet S on which an image is formed during single-sided printing. The second surface is a surface facing the first surface of the sheet S. In the present embodiment, the recording head 83 has a plurality of heads corresponding to four colors arranged in parallel from the upstream side to the downstream side in the transport direction D. Each head includes a plurality of nozzles (not shown) arranged along the width direction (X-axis direction) of the transport mechanism 81. Ink is ejected onto the sheet S from a plurality of nozzles.

  The sheet S on which an image is formed is conveyed to the first conveyance path 60. The first transport path 60 is disposed downstream of the image forming unit 80 in the transport direction D of the sheet S. The first transport path 60 includes a transport roller pair 61. The sheet S conveyed on the first conveyance path 60 by the conveyance roller pair 61 is conveyed to the second conveyance path 70 when forming an image on the second surface of the sheet S, and forms an image on the second surface of the sheet S. If not, it is conveyed to the discharge tray 400. The discharge tray 400 is disposed outside the housing 100, and the sheet S is discharged to the discharge tray 400.

  In the second conveyance path 70, the sheet S is conveyed again to the image forming unit 80. The second conveyance path 70 is branched from the first conveyance path 60 and is disposed above the image forming unit 80. The storage unit 10 is provided in the second conveyance path 70. The sheet S conveyed through the second conveyance path 70 is switched in the conveyance direction D in the storage unit 10 and is conveyed again to the image forming unit 80. Accordingly, the second surface of the sheet S re-conveyed to the image forming unit 80 faces the recording head 83.

  The storage unit 10 stores the sheet S that enters the storage unit 10. The sheet S entering the storage unit 10 has a first surface of the sheet S curled in a convex shape. Hereinafter, in this specification, the direction of curl that the first surface warps in a convex shape in a cross-sectional view from the width direction of the sheet S is referred to as a convex direction, and the first surface in a cross-sectional view from the width direction of the sheet S. The direction of curl that warps in a concave shape is described as a concave direction. The width direction of the sheet S is a direction orthogonal to the conveyance direction D of the sheet S.

  The sensor 71 is disposed adjacent to the storage unit 10 along the second conveyance path 70. The sensor 71 has a light emitting element and a light receiving element. The light emitting element irradiates the sheet S, and the light receiving element receives the light reflected from the sheet S. The distance from the sensor 71 to the sheet S is detected based on the light received by the light receiving element. By fixing the arrangement of the sensor 71 in advance, the distance from the sheet S to the second conveyance path 70 is measured based on the distance from the sensor 71 to the sheet S. The sensor 71 detects the amount of curl in the convex direction of the sheet S by measuring the distance from the end of the sheet S entering the storage unit 10 to the second conveyance path 70.

  The control unit 50 controls each element of the inkjet recording apparatus 1. Specifically, the control unit 50 executes a computer program stored in a storage device such as a main storage device (for example, a semiconductor memory) or an auxiliary storage device (for example, a hard disk drive). The sensor 71, the image forming unit 80, the feeding unit 200, and the transport unit 300 are controlled. The control unit 50 is, for example, a CPU (Central Processing Unit).

  Next, the storage unit 10 will be described with reference to FIGS. 1 and 2. FIG. 2 shows the storage unit 10. The storage unit 10 includes a storage unit 20, a correction unit 30, a retard roller 41, a feed roller 42, and three pressing units 90.

  The storage unit 20 stores the sheet S. The storage unit 20 includes a guide plate 21 and a sheet front end guide 23. The guide plate 21 is substantially L-shaped in a side view. The sheet S entering the storage unit 10 is stacked on the guide plate 21. The guide plate 21 is inclined with respect to the receiving surface 22 on which the rear end of the sheet S entering the storage unit 10 is stacked and the front end of the sheet S entering the storage unit 10 facing downward. And an inclined surface 24. The receiving surface 22 and the inclined surface 24 of the guide plate 21 are flat. In the present embodiment, a plurality of sheets S are stacked on the guide plate 21, but a single sheet S may be stacked on the guide plate 21.

  The sheet front end guide 23 receives the front end of the sheet S entering the storage unit 10. The leading edge of the sheet S entering the storage unit 10 may be the trailing end of the sheet S that is re-conveyed from the storage unit 10 to the image forming unit 80. The sheet front end guide 23 is attached so as to be movable along the inclined surface 24 and is normally biased in a direction away from the lower end portion of the guide plate 21. The urging force with respect to the sheet leading end guide 23 is smaller than the resultant force of the moving force due to the weight of the sheet leading end guide 23 and the impact force when the sheet S comes into contact with the sheet leading end guide 23. Accordingly, the sheet leading guide 23 moves toward the lower end portion of the guide plate 21 due to an impact when the sheet S comes into contact with the sheet leading guide 23. That is, the sheet front end guide 23 moves toward the lower end portion of the guide plate 21. The position of the sheet leading end guide 23 is determined according to the number of sheets S and the weight of the sheet S. As a result, the tips of the plurality of sheets S stacked on the guide plate 21 are arranged. The sheet leading end guide 23 can move to a position where it abuts against the lower end of the guide plate 21.

  The correction unit 30 curls the sheet S entering the storage unit 10 in the concave direction. The correction unit 30 includes a correction plate 32, a feeding unit 33, and a correction shaft 323. The correction plate 32 functions as an entry guide for the sheet S, and the sheet S enters the storage unit 10 along the correction plate 32. The correction plate 32 is normally biased in a direction away from the receiving surface 22 of the guide plate 21. Details of the correction plate 32 will be described later with reference to FIG. The feeding unit 33 feeds the sheet S curled in the concave direction between the retard roller 41 and the feed roller 42. Details of the feeding unit 33 will be described later with reference to FIGS. 4 and 5.

  Each of the three pressing portions 90 includes a pressing roller 91, a pressing shaft 92, and a pressing arm 93. The pressing roller 91 and the pressing shaft 92 are connected by a pressing arm 93. The pressing roller 91 rotates with the pressing shaft 92 as a fulcrum, and presses the sheets S stacked on the guide plate 21 toward the inclined surface 24 of the guide plate 21. Therefore, the sheet S curled in the convex direction is pressed so as to be flat.

  In the present embodiment, two pressing portions 90 of the three pressing portions 90 rotate to hold the sheet S. Based on the size of the conveyed sheet S, it may be determined whether or not the three pressing portions 90 rotate, or the three pressing portions 90 may rotate without being determined. A device that can detect the position of the sheet is provided in each of the three pressing portions 90, and the three pressing portions 90 are determined by determining whether or not the sheet S is positioned immediately below each of the three pressing portions 90. Each may rotate.

  The retard roller 41 and the feed roller 42 convey the sheet S fed by the feeding unit 33 toward the second conveyance path 70. The retard roller 41 and the feed roller 42 face each other. The feed roller 42 moves toward the retard roller 41, and the feed roller 42 and the retard roller 41 are pressed against each other. When one sheet S has been fed, the retard roller 41 rotates following the feed roller 42. On the other hand, when a plurality of sheets S are overlapped and fed, the retard roller 41 rotates in the direction opposite to the conveyance direction D of the sheet S, or the retard roller 41 stops and comes into contact with the feed roller 42. The other sheet S is separated from the existing sheet S. As a result, one sheet S is conveyed by the feed roller 42.

  As described above with reference to FIGS. 1 and 2, according to the present embodiment, the sheet S is curled in the concave direction by the correction unit 30. Therefore, curling of the sheet S in the convex direction by the ink can be suppressed. As a result, the sheet S re-conveyed to the image forming unit 80 can be prevented from contacting the recording head 83.

  Further, according to the present embodiment, the sheet S curled in the convex direction is stacked on the flat surface of the guide plate 21. Therefore, curling of the sheet S in the convex direction is suppressed. As a result, it is possible to further suppress contact of the sheet S re-conveyed to the image forming unit 80 with the recording head 83.

  Further, according to the present embodiment, the sheet S is curled in the concave direction, that is, the leading edge of the sheet S that is re-conveyed to the image forming unit 80 is curled toward the conveyance mechanism 81. Accordingly, the suction unit 811 of the transport mechanism 81 can suck the sheet S with a small negative pressure. As a result, the driving force of the suction unit 811 can be reduced, and the load on the suction unit 811 can be reduced.

  Next, the operation of the correction plate 32 will be described with reference to FIGS. FIG. 3 shows the operation of the correction plate 32. The correction shaft 323 is fixedly attached to the proximal end of the correction plate 32. The control unit 50 controls the driving force generated by the first motor 313 to rotate the correction shaft 323, and the correction plate 32 rotates with the rotation of the correction shaft 323. After the plurality of sheets S are stacked on the guide plate 21, the correction plate 32 rotates in the direction of the arrow R <b> 1 with the correction shaft 323 as a fulcrum so that the sheet S is moved toward the receiving surface 22 of the guide plate 21. Hold down. The rear end of the sheet S entering the storage unit 10 is sandwiched between the receiving surface 22 and the correction plate 32. In the present embodiment, the arrow direction R1 is counterclockwise.

  According to the present embodiment, the sheet S is pressed along the guide plate 21 by the correction plate 32 and the three pressing portions 90. Accordingly, the sheet S is curled in the concave direction. As a result, curling in the convex direction of the sheet S can be suppressed. After the sheet S is curled in the concave direction, the correction plate 32 rotates in the direction indicated by the arrow R2, so that the correction unit 30 returns to the state shown in FIG. In the present embodiment, the arrow direction R2 shown in FIG. 3 is clockwise.

  As described above with reference to FIGS. 2 and 3, according to the present embodiment, the correction plate 32 curls the rear end of the sheet S entering the storage unit 10 in the concave direction. Accordingly, it is possible to suppress the leading edge of the sheet S when being re-conveyed to the image forming unit 80 from curling toward the recording head 83. As a result, it is possible to further suppress contact of the sheet S re-conveyed to the image forming unit 80 with the recording head 83.

  Further, according to the present embodiment, the correction plate 32 curls the plurality of sheets S stacked on the guide plate 21 simultaneously in the concave direction. Therefore, compared with the case where the sheets S are curled one by one, the time for curling the plurality of sheets S in the concave direction can be shortened while maintaining the time for curling each of the plurality of sheets S in the concave direction. As a result, it is possible to suppress an increase in the conveyance time from when the plurality of sheets S are conveyed to the discharge tray 400. That is, it is possible to suppress a decrease in productivity of the sheet S on which the image of the inkjet recording apparatus 1 is formed.

  With reference to FIG.2 and FIG.3, the time for the correction plate 32 to hold down the sheet | seat S toward the receiving surface 22 of the guide plate 21 is demonstrated. The control unit 50 changes the time during which the correction plate 32 presses the sheet S toward the receiving surface 22 of the guide plate 21 by controlling the driving force generated by the first motor 313. Hereinafter, in the present specification, the time during which the correction plate 32 presses the sheet S toward the receiving surface 22 of the guide plate 21 is referred to as the correction time of the sheet S.

  The control unit 50 changes the correction time of the sheet S based on the density of the image formed on the sheet S. Specifically, the higher the density of the image formed on the sheet S, the greater the amount of ink ejected onto the sheet S, and the greater the curling of the sheet S in the convex direction by the ink. Therefore, the control unit 50 increases the correction time of the sheet S as the density of the image formed on the sheet S increases. As a result, curling of the sheet S in the convex direction is suppressed.

  When a plurality of sheets S are stacked on the guide plate 21, the control unit 50 may change the correction time of the sheets S based on the highest density among the densities of images formed on the plurality of sheets S. . Further, the control unit 50 may calculate the average value of the density of the images formed on the plurality of sheets S, and change the correction time of the sheet S based on the average value of the density of the images. In addition, the control unit 50 may set a density first threshold value and change the correction time of the sheet S based on the number of images formed with a density equal to or higher than the first threshold value.

  Further, the control unit 50 changes the correction time of the sheet S based on the position of the image formed on the sheet S. Specifically, the closer the position of the image formed on the sheet S is to the front end of the sheet S that is re-conveyed to the image forming unit 80, the more the front end of the sheet S curls in a convex direction. Easy to touch. Therefore, the control unit 50 increases the correction time of the sheet S as the position of the image formed on the sheet S is closer to the leading end of the sheet S that is re-conveyed to the image forming unit 80. As a result, curling in the convex direction of the leading edge of the sheet S re-conveyed to the image forming unit 80 is suppressed.

  When a plurality of sheets S are stacked on the guide plate 21, the control unit 50 is formed at a position closest to the front end of the sheet S re-conveyed to the image forming unit 80 among the images formed on the plurality of sheets S. Based on the position of the image to be corrected, the correction time of the sheet S may be changed. Further, the control unit 50 calculates the average value of the length from the position of the image formed on the plurality of sheets S to the leading edge of the sheet S re-conveyed to the image forming unit 80, and based on the average value of the lengths Thus, the correction time of the sheet S may be changed. Moreover, the control part 50 may set the 2nd threshold value of length. The control unit 50 may change the correction time of the sheet S based on the number of images having a short length from the position of the image formed on the sheet S to the leading edge of the sheet S at or above the second threshold.

  Here, if the position of the image formed on the sheet S is not close to the leading edge of the sheet S re-conveyed to the image forming unit 80, the sheet S may not contact the recording head 83. Therefore, if the position of the image formed on the sheet S is not close to the front end of the sheet S, the correction plate 32 does not have to press the sheet S toward the receiving surface 22 of the guide plate 21.

  Further, the control unit 50 changes the correction time of the sheet S based on the thickness of the sheet S. Specifically, the thinner the sheet S, the greater the curling of the sheet S in the convex direction by the ink. Therefore, the control unit 50 increases the correction time of the sheet S as the sheet S is thinner. As a result, curling of the sheet S in the convex direction is suppressed. When a plurality of sheets S are stacked on the guide plate 21, the control unit 50 may change the correction time of the sheet S based on the thinnest sheet S among the plurality of sheets S. The average value of the thickness of the sheet S may be calculated to change the correction time of the sheet S.

  Further, the control unit 50 may change the correction time of the sheet S based on the distance from the sheet S to the second conveyance path 70 detected by the sensor 71, that is, the curl size in the convex direction of the sheet S. Good. The larger the curl size of the sheet S entering the storage unit 10, the easier the sheet S re-conveyed to the image forming unit 80 comes into contact with the recording head 83. Therefore, the correction time of the sheet S is increased as the curl in the convex direction of the sheet S detected by the sensor 71 is increased.

  The size of the curl in the convex direction of the sheet S varies depending on the temperature or humidity when an image is formed on the sheet S, or the paper quality of the sheet S. According to the present embodiment, the correction time of the sheet S can be changed according to the detected curl size in the convex direction of the sheet S. As a result, curling of the sheet S in the convex direction is further suppressed.

  The control unit 50 changes the correction time of the sheet S based on at least one of the image formed on the sheet S described above, the thickness of the sheet S, and the curl size in the convex direction of the sheet S. Alternatively, the correction time of the sheet S may be changed based on a combination of two or more. In addition, the structure of the correction | amendment part 30 demonstrated by this embodiment is an example, and if it has a structure which can change arbitrarily the time for which the correction board 32 presses the sheet | seat S toward the guide board 21, it will be in this embodiment. It is not limited.

  Next, the number of sheets S stacked on the guide plate 21 will be described with reference to FIGS. The control unit 50 controls each conveyance roller that conveys the sheet S provided in the inkjet recording apparatus 1 and changes the number of sheets S stacked on the guide plate 21, so that the correction plate 32 receives the guide plate 21. The number of sheets S pressed toward the stop surface 22 is changed. The smaller the number of sheets S pressed by the correction plate 32 toward the receiving surface 22 of the guide plate 21, the easier the sheet S curls in the concave direction. That is, the smaller the number of sheets S stacked on the guide plate 21, the easier the sheet S curls in the concave direction.

  The control unit 50 changes the number of sheets S stacked on the guide plate 21 based on the density of the image formed on the sheet S. Specifically, the control unit 50 reduces the number of sheets S stacked on the guide plate 21 as the density of the image formed on the sheet S is higher. As a result, curling of the sheet S in the convex direction is suppressed, and the sheet S is effectively curled in the concave direction.

  Further, the control unit 50 changes the number of sheets S stacked on the guide plate 21 based on the position of the image formed on the sheet S. Specifically, the control unit 50 reduces the number of sheets S stacked on the guide plate 21 as the position of the image formed on the sheet S is closer to the leading edge of the sheet S re-conveyed to the image forming unit 80. To do. As a result, the curling of the sheet S in the convex direction is further suppressed, and the sheet S re-conveyed to the image forming unit 80 can be further prevented from contacting the recording head 83.

  Further, the control unit 50 changes the number of sheets S stacked on the guide plate 21 based on the thickness of the sheets S. Specifically, the control unit 50 decreases the number of sheets S stacked on the guide plate 21 as the thickness of the sheets S is thinner. As a result, the curling of the sheet S in the convex direction is further suppressed, and the sheet S is curled in the concave direction more effectively.

  According to the present embodiment, the number of sheets S stacked on the guide plate 21 is changed. Accordingly, the sheet S can be curled in the concave direction according to the density of the image formed on the sheet S, the position of the image formed on the sheet S, or the thickness of the sheet S. As a result, curling of the sheet S in the convex direction is further suppressed.

  The feeding unit 33 will be described with reference to FIGS. 1, 4 and 5. FIG. 4 shows the correction unit 30 from above. FIG. 5A shows the feeding unit 33 located at the standby position. A feeding hole 321 is formed in the correction plate 32. The standby position of the feeding unit 33 is a position where the feeding unit 33 is retracted upward with respect to the correction plate 32. The feeding unit 33 includes a feeding shaft 331, a frame 332, and a pickup roller 334 attached to the frame 332. The feeding shaft 331 is fixed to the frame 332, and the frame 332 rotates with the rotation of the feeding shaft 331. As the frame 332 rotates in the arrow direction R <b> 3, the pickup roller 334 passes through the feeding hole 321 and descends to a position where it contacts the sheet S. In the present embodiment, the arrow direction R3 shown in FIG. 4 is counterclockwise.

  The pickup roller 334 is connected to the second motor 335 via the frame 332 and the feeding shaft 331. The driving force of the second motor 335 is transmitted to the pickup roller 334 via the feeding shaft 331 and the frame 332. The control unit 50 controls the driving force generated by the second motor 335 to rotate the feeding shaft 331 and rotate the pickup roller 334.

  FIG. 5B shows the feeding unit 33 located at the feeding position. When the sheet S feeding operation is started, the feeding unit 33 rotates from the standby position to the feeding position. The feeding position of the feeding unit 33 is a position where the pickup roller 334 contacts the sheet S. Specifically, the frame 332 rotates as the feeding shaft 331 rotates, and the pickup roller 334 contacts the sheet S. The sheet S is fed toward a position where the sheet S is nipped by the retard roller 41 and the feed roller 42 by the rotation of the pickup roller 334. When the feeding of the sheet S is completed, the control unit 50 rotates the feeding shaft 331 in the arrow direction R4, so that the feeding unit 33 returns to the standby position as shown in FIG. In the present embodiment, the arrow direction R4 shown in FIG. 4 is clockwise.

  The embodiments of the present invention have been described above with reference to the drawings (FIGS. 1 to 5). However, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof (for example, (1) to (7) shown below). In order to facilitate understanding, the drawings schematically show each component as a main component, and the thickness, length, number, and the like of each component shown in the drawings are different from the actual for convenience of drawing. . Moreover, the shape, dimension, etc. of each component shown by said embodiment are an example, Comprising: It does not specifically limit, A various change is possible in the range which does not deviate substantially from the effect of this invention.

  (1) In this embodiment, when an image is not formed on the sheet S, the storage unit 10 does not have to curl the sheet S by the correction unit 30. As a result, the inkjet recording apparatus 1 can shorten the conveyance time of the sheet S.

  (2) As described with reference to FIGS. 2 and 3, the storage unit 10 includes three pressing units 90. However, the storage unit 10 may include one pressing unit 90 or may include a plurality of pressing units 90 other than three.

  (3) As described with reference to FIGS. 2 and 3, the pressing portion 90 presses the sheet S by the pressing roller 91. However, the pressing unit 90 may be a fan, and may press the sheet S by blowing air.

  (4) As described with reference to FIG. 1, the recording head 83 has a plurality of heads corresponding to four colors. However, the recording head 83 may have a head corresponding to one color or a plurality of heads corresponding to a plurality of colors other than four colors.

  (5) As described with reference to FIGS. 1 to 3, the sheet S stored in the storage unit 10 is prevented from being conveyed by the retard roller 41 and the feed roller 42 overlapping each other. To do. However, instead of the retard roller 41, the separation pad and the feed roller 42 may prevent the plurality of sheets S from being overlapped and conveyed.

  (6) As described with reference to FIG. 2, the sheets S are stacked on the guide plate 21. A pair of cursors may be provided at both ends along the width direction of the guide plate 21. The pair of cursors sandwich the sheet S stacked on the guide plate 21 and suppress the conveyance of the sheet S in an oblique posture.

  (7) As described with reference to FIGS. 4 and 5, the first motor 313 rotates the correction shaft 323 and the second motor 335 rotates the feeding shaft 331. However, the first motor 313 may rotate the correction shaft 323 and the feeding shaft 331, and the second motor 335 may rotate the correction shaft 323 and the feeding shaft 331.

  The present invention can be used in the field of inkjet recording apparatuses.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 10 Storage part 21 Guide plate 32 Correction board 50 Control part 60 1st conveyance path 70 2nd conveyance path 80 Image formation part 90 Pressing part S Sheet

Claims (9)

An inkjet recording apparatus that forms an image on a sheet by an image forming unit,
A first conveyance path for conveying the sheet on which the image is formed, and a second conveyance path for branching from the first conveyance path and re-conveying the sheet to the image forming unit;
A control unit, and a storage unit that is provided in the second conveyance path and stores the sheet,
The storage unit includes a guide plate on which the sheets are stacked, and a correction plate that presses the sheet toward the guide plate,
The said control part is an inkjet recording device which changes the time when the said correction plate presses the said sheet | seat toward the said guide plate.   The ink jet recording apparatus according to claim 1, wherein the control unit changes a time for which the correction plate presses the sheet toward the guide plate based on a density of an image formed on the sheet.   The ink jet recording apparatus according to claim 1, wherein the control unit changes a time during which the correction plate presses the sheet toward the guide plate based on a position of an image formed on the sheet. .   4. The inkjet recording apparatus according to claim 1, wherein the control unit changes a time during which the correction plate presses the sheet toward the guide plate based on the thickness of the sheet. 5. . A sensor for measuring a distance from the sheet entering the storage unit to the second transport path;
The sensor is disposed along the second transport path,
5. The ink jet recording apparatus according to claim 1, wherein the control unit changes a time during which the correction plate presses the sheet toward the guide plate based on the distance. 6.   6. The inkjet recording apparatus according to claim 1, wherein the control unit changes the number of the sheets stacked on the guide plate based on a density of an image formed on the sheet. .   The ink jet recording apparatus according to claim 1, wherein the control unit changes the number of the sheets stacked on the guide plate based on a position of an image formed on the sheet. .   8. The inkjet recording apparatus according to claim 1, wherein the control unit changes the number of sheets stacked on the guide plate based on the thickness of the sheet.   The inkjet recording apparatus according to claim 1, wherein the storage unit further includes a pressing unit that presses the sheet toward the guide plate.

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