JP5302786B2 - Belt conveying apparatus and ink jet recording apparatus provided with the same - Google Patents

Description

  The present invention relates to a belt conveyance device that conveys a recording medium while adsorbing it onto an endless conveyance belt, and an ink jet recording apparatus including the belt conveyance device.

  The ink jet recording apparatus ejects fine particles of ink from a nozzle provided in an ink jet head onto a recording medium such as paper and prints characters and figures in a dot pattern. The medium is conveyed by a belt conveyance device.

  By the way, as a belt conveyance device, one that conveys a recording medium such as a sheet while adsorbing it onto an endless conveyance belt in which a plurality of suction holes are formed is known, and a proposal regarding such a belt conveyance device is now available. It has been various.

  For example, Patent Document 1 proposes a belt conveyance device in which the type of a recording medium is detected by a detection unit, and the suction fan is controlled so as to obtain a suction force according to the detected type of the recording medium. Yes.

  Also, in Patent Document 2, in order to improve the running stability of the conveyor belt, the diameters of the plurality of holes formed in the conveyor belt are set so that the central portion is smaller than both ends in the width direction of the conveyor belt. A configuration is proposed.

JP-A-3-000270 JP 2002- 211788 A

  By the way, in a belt conveying apparatus that employs a method of conveying a recording medium while adsorbing it onto a conveying belt, the lifting and curling of both ends in the width direction of the recording medium becomes a problem. In the ink jet recording apparatus provided with such a belt conveyance device, when turning over a predetermined amount occurs at both ends in the width direction of the recording medium being conveyed, the nozzle surface of the print head is moved when the recording medium passes through the print area. Problems such as rubbing the printed image and jamming occur.

  Therefore, in the suction conveyance of the recording medium, it is an important issue how to efficiently suck both ends in the width direction of the recording medium to prevent the turning.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the object of the present invention is to reduce the image quality by a belt conveyance device capable of reliably attracting the recording medium to the conveyance belt and preventing the occurrence of turning regardless of the size. Another object of the present invention is to provide an ink jet recording apparatus that can stably generate a high-quality image by preventing occurrence of jam and jam.

In order to achieve the above object, a first aspect of the present invention is a belt conveyance system comprising: an endless conveyance belt in which a plurality of suction holes having the same diameter are formed; and an adsorption unit that adsorbs a recording medium onto the conveyance belt. In the device
The interval at the central portion in the width direction of the suction hole of the conveyor belt is set larger than the interval at both ends in the width direction to minimize the number of suction holes in the central portion in the width direction ,
In the width direction of the conveyor belt, the interval between the suction holes in the intermediate portion between the width direction both ends and the width direction central portion is set to the minimum, and the number of suction holes in the intermediate portion is maximized,
The number of suction holes at both ends in the width direction of the conveyor belt is set to be intermediate between the number at the center portion in the width direction and the number at the intermediate portion .

  According to a second aspect of the present invention, an ink jet recording apparatus that performs printing by ejecting ink onto a recording medium conveyed by a conveying belt includes the belt conveying apparatus according to the first aspect.

  According to invention of Claim 1, while setting the space | interval in the width direction both ends of the suction hole of a conveyance belt smaller than the space | interval in the width direction center part, it is an intermediate | middle between the width direction both ends and the width direction center part. Since the gap between the suction holes in the section is set to the minimum, the small-sized recording medium has the smallest suction hole spacing in the middle part where the width direction both ends are located between the width direction both ends and the width direction center. The suction force through the suction holes at both ends in the width direction of the recording medium is larger than that at other parts. For this reason, the small-size recording medium is reliably prevented from turning up at both ends in the width direction, and is conveyed while being in close contact with the conveying belt.

  On the other hand, since a large-sized recording medium closes most of the suction holes of the conveyance belt, the negative pressure generated in each suction hole becomes large. Accordingly, even if the number of suction holes at both ends in the width direction of the conveyance belt where the both ends in the width direction of the recording medium are slightly small, the suction force of each suction hole is increased, and the width of the large-sized recording medium The suction force at both ends in the width direction of the conveying belt where both ends in the direction are located is large enough to prevent turning up at both ends in the width direction of the recording medium. For this reason, the large-size recording medium is reliably prevented from turning up at both ends in the width direction, and is conveyed while being in close contact with the conveyance belt.

  As a result, regardless of the size, the recording medium can be reliably attracted to the transport belt and the occurrence of turning up at both ends in the width direction can be prevented.

  According to the second aspect of the present invention, the recording medium can be reliably adsorbed to the conveying belt regardless of the size and the occurrence of turning up at both ends in the width direction can be prevented. Therefore, when the recording medium passes through the print area. A high-quality image can be stably obtained without causing problems such as the print image being rubbed or jamming due to rubbing the nozzle surface of the print head.

1 is a side view showing a basic configuration of an ink jet recording apparatus according to the present invention. It is a top view of the conveyance belt of the conveyance belt device concerning the present invention. FIG. 4A is a plan view of a conveyance belt showing a state in which small-size paper is sucked and conveyed in the conveyance belt device according to the present invention, and FIG. 5B is a conveyance belt showing a state in which large-size paper is sucked and conveyed. FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a side view showing a basic configuration of an ink jet recording apparatus according to the present invention, FIG. 2 is a plan view of a conveying belt of the belt apparatus according to the present invention, and FIG. 3A is a small size in the conveying belt apparatus according to the present invention. FIG. 5B is a plan view of the conveyance belt showing a state in which the sheet of paper is sucked and conveyed, and FIG. 9B is a plan view of the conveyance belt showing a state of sucking and conveying a large size sheet.

  An ink jet recording apparatus 1 shown in FIG. 1 is a color printer, and includes a belt conveyance device 2 according to the present invention and a discharge device 3 arranged on the downstream side in the paper conveyance direction (left side in FIG. 1).

  The belt conveyance device 2 is a device that conveys a paper P that is a recording medium, and includes an endless conveyance belt 4 that sucks and conveys the paper P. An inkjet head is disposed above the conveyance belt 4. 5 is arranged. Here, the inkjet head 5 corresponds to each color of black (BK), cyan (C), magenta (M), and yellow (Y) arranged in parallel along the transport direction (left direction in FIG. 1) of the paper P. The print heads 5a, 5b, 5c and 5d are provided. The inkjet head 5 is a so-called line type, and has a printable area equivalent to a width perpendicular to the transport direction of the paper P.

  Further, the conveying belt 4 is wound around a driving roller 6, a driven roller 7, and a tension roller 8, and is rotated by the driving roller 6 in the arrow direction (counterclockwise direction) of FIG. Transport in the T direction. A suction unit 9 serving as a suction unit is disposed on the back side of the transport belt 4 and at a position facing the inkjet head 5.

  The suction unit 9 is a vacuum suction device, and includes a transport plate 10 provided on the back side of the transport belt 4, a decompression case 11 provided at a lower portion of the transport plate 10, and a lower portion of the decompression case 11. The fan 12 is provided. Here, a plurality of slits (not shown) are formed in the transport plate 10, and the transport belt 4 moves on the transport plate 10. A negative pressure is generated in the decompression case 11 by the rotation of the fan 12.

  Thus, as shown in FIG. 2, the conveying belt 4 is formed with a plurality of suction holes 4a having the same diameter, and the distance between the suction holes 4a at both ends 4A in the width direction is 4B. The distance between the suction holes 4a in the intermediate part 4C between the width direction both ends 4A and the width direction center part 4B is set to the minimum. That is, the number of the suction holes 4a at the center part 4B in the width direction of the transport belt 4 is the smallest, the number of the suction holes 4a at the middle part 4C on the left and right sides is the largest, and the suction holes at the both end parts 4A in the width direction. The number 4a is in the middle (the second most common number). In other words, in the present embodiment, the number of suction holes 4a in the central portion 4B in the width direction of the conveyor belt 4 is reduced, and the reduced number of suction holes 4a is provided in other regions (the width direction both ends 4A and the intermediate portion 4C). By distributing, the number of suction holes 4 a is distributed in the width direction of the conveyor belt 4. Here, the “width direction of the conveyance belt 4” means a direction perpendicular to the conveyance direction of the paper P by the conveyance belt 4.

  On the other hand, the discharge device 3 disposed on the downstream side (left side in FIG. 1) of the belt conveyance device 2 in the paper conveyance direction is the same as the conveyance belt 4 in the same direction with the printed paper P conveyed by the conveyance belt 4. The sheet P is transported in the direction of arrow Q and sent to a stock apparatus (not shown) disposed downstream thereof, and is configured as follows.

  That is, as shown in FIG. 1, the discharge device 3 includes an endless discharge belt 13, and the discharge belt 13 is wound around a driving roller 14, a driven roller 15, and a tension roller 16. In addition, a discharge guide 17 that is inclined downward toward the downstream side is provided at a transfer portion of the paper P from the transport belt 4 to the discharge belt 13, and the paper P conveyed by the transport belt 4 is discharged from the discharge guide 17. 17 is delivered to the discharge belt 13 while being guided by 17.

  Further, a suction device 18 is disposed on the back side of the discharge belt 13, and this suction device 18 passes a sheet P conveyed on the discharge belt 13 through a suction hole (not shown) formed in the discharge belt 13. The sheet P is securely held on the discharge belt 13 by being sucked by an air pump (not shown). Note that a charging roller can be used for the suction device 18. In this case, the discharge belt 13 is charged by applying a charging voltage of several kV (for example, 2 kV) to the charging roller by a DC power source, and the sheet P is attracted and held on the upper surface of the discharge belt 13 by this charging. Can do.

  Next, the operation of the inkjet recording apparatus 1 having the above configuration will be described.

  In the ink jet recording apparatus 1 according to the present embodiment, the paper P supplied from the right direction in FIG. 1 to the left direction (the direction of arrow T in FIG. 1) by the paper supply device (not shown) It is held tightly on the conveyor belt 4 by the air suction operation. That is, when the fan 12 of the suction unit 9 is driven to rotate, a negative pressure is generated in the decompression case 11, and air in the atmosphere is formed in the suction holes 4 a of the transport belt 4 and the transport plate 10 by this negative pressure. Since the sheet P is sucked into the decompression case 11 through a slit (not shown), the sheet P is vacuum-sucked on the transport belt 4.

  Thus, the sheet P adsorbed on the conveyor belt 4 is downstream (left side in FIG. 1) at a predetermined speed by the conveyor belt 4 that is driven to rotate in the direction of the arrow (counterclockwise) in FIG. ). In the process in which the sheet P is conveyed downstream by the conveying belt 4 in this way, black (BK), cyan (C), magenta (M), and yellow (Y) are printed on the sheet P. Each color ink is ejected according to image data by the heads 5a, 5b, 5c, and 5d, and finally a full color image is printed on the paper P by superimposing the respective colors.

  The paper P on which a full-color image is printed through the above process is sent to the discharge device 3. That is, the paper P is fed from the transport belt 4 to the discharge belt 13 of the discharge device 3 along the discharge guide 17 provided in the discharge device 3. In the discharge device 3, the discharge roller 13 is driven to rotate in the direction of the arrow (counterclockwise) in FIG. 1 at the same speed as the transport belt 4 by the drive roller 14 being rotated. 4 is smoothly fed to the discharge belt 13, conveyed in the direction of arrow Q in FIG. 1 by the discharge belt 13, discharged to a stock device (not shown), and stocked.

  Here, in the belt conveyance device 2 according to the present invention, when the small-size paper P1 and the large-size paper P2 are conveyed, the adsorbing states of the respective sheets P1, P2 to the conveyance belt 4 are shown in FIGS. Each will be described based on b).

  As shown in FIG. 3A, the small-size paper P1 has a minimum distance between the suction holes 4a between the width direction both ends 4A and the width direction center 4B of the transport belt 4 at the both ends in the width direction (suction). (The number of holes 4a is the largest) in the intermediate portion 4C, and through the suction holes (multiple suction holes formed in the intermediate portion 4C of the conveyor belt 4) 4a at both ends in the width direction of the paper P1. The suction force is greater than that of other parts. For this reason, the small size paper P1 is reliably prevented from being turned up at both ends in the width direction, and is conveyed in a state of being in close contact with the conveyance belt 4.

  On the other hand, as shown in FIG. 3B, the large-size paper P2 has a large negative pressure generated in each suction hole 4a in order to close most of the suction holes 4a of the transport belt 4. Accordingly, even if the number of suction holes 4a at both ends 4A in the width direction of the conveyance belt 4 where the both ends in the width direction of the paper P2 are slightly small, the suction force of each suction hole 4a increases, and the large size The suction force at both ends 4A in the width direction of the conveyance belt 4 where both ends in the width direction of the paper P2 are located is large enough to prevent turning up at both ends in the width direction of the paper P2. For this reason, the large-size paper P2 is also reliably conveyed with its both ends in the width direction prevented from being turned up and in close contact with the conveyor belt 4.

  As a result, regardless of the size, the paper P (P1, P2) can be reliably attracted to the transport belt 4 to prevent the turning of both ends in the width direction. For this reason, in the ink jet recording apparatus 1 shown in FIG. 1, when the paper P passes through the print region, there are problems such as the print images being rubbed against the nozzle surfaces of the print heads 3a to 3d and jamming. Therefore, it is possible to stably obtain a high quality image.

DESCRIPTION OF SYMBOLS 1 Inkjet recording apparatus 2 Belt conveying apparatus 3 Ejection apparatus 4 Conveying belt 4A Both ends in the width direction of the conveying belt 4B The central part in the width direction of the conveying belt 4C The intermediate part of the conveying belt 4a The suction hole of the conveying belt 5 Inkjet heads 5a to 5d Print head 6 Driving roller 7 Driven roller 8 Tension roller 9 Suction unit (Suction means)
DESCRIPTION OF SYMBOLS 10 Conveying plate 11 Decompression case 12 Fan 13 Discharge belt 14 Drive roller 15 Driven roller 16 Tension roller 17 Discharge guide 16 Roller shaft 17 Discharge guide 18 Adsorption device P Paper (recording medium)
P1 Small size paper P2 Large size paper

Claims (2)

In a belt conveyance device comprising an endless conveyance belt in which a plurality of suction holes having the same diameter are formed, and an adsorption means for adsorbing a recording medium on the conveyance belt,
The interval at the central portion in the width direction of the suction hole of the conveyor belt is set larger than the interval at both ends in the width direction to minimize the number of suction holes in the central portion in the width direction ,
In the width direction of the conveyor belt, the interval between the suction holes in the intermediate portion between the width direction both ends and the width direction central portion is set to the minimum, and the number of suction holes in the intermediate portion is maximized,
The belt conveying apparatus characterized in that the number of suction holes at both ends in the width direction of the conveying belt is set to be intermediate between the number in the central portion in the width direction and the number in the intermediate portion .
  An ink jet recording apparatus comprising: the belt conveying device according to claim 1, wherein the apparatus performs printing by discharging ink onto a recording medium conveyed by a conveying belt.

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