JP2006334943A - Inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording apparatus capable of suppressing influences of curls generated in a recording medium caused by sticking of an ink, achieving a good quality of printing by suppressing floating-up of the recording medium on the lower part of a recording head, and guiding stably the recording medium to the discharging part on the downstream. <P>SOLUTION: The inkjet recording apparatus is equipped with a carrying conveyor 28 for carrying the recording medium in the definite direction, a recording head 32 delivering the ink toward the recording medium carried by the carrying conveyor to record an image, a discharging means adjoining the downstream side of the carrying conveyor and releasing the recording medium on which the image is recorded by the recording head from the carrying conveyor and discharging it, and an air jetting guide member for blowing an air flow toward the carrying conveyor. The air jetting guide member has a first jetting hole for blowing the air flow at the more upstream side than a roller of the discharging side positioned on the end part of the downstream side and on the more downstream side than the recording head. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and in particular, even when water-based ink is used, the recording surface of the recording medium is curled after printing, resulting in paper jams, printing surface scratches, paper tip breaks, scratches, etc. The present invention relates to an ink jet recording apparatus that can effectively prevent the occurrence of defects.

  In an ink jet recording apparatus, printing is generally performed by ejecting water-based ink. Therefore, on a recording medium, the surface on the printing side is stretched by the attached ink and curls toward the surface on which no image is recorded. There was a trend.

  When curling occurs on the recording medium after printing, the recording medium is lifted from the conveyor that conveys the recording medium, the printing surface is rubbed against the recording head that ejects ink, and the printing surface becomes dirty or the recording medium is not discharged smoothly. This causes problems such as paper jams, breakage of the tip of the recording medium, and damage to the recording medium.

Therefore, even if the recording medium is curled with ink, it will not lift from the conveying means such as a conveyor.
In an image forming apparatus including a conveying unit that conveys a sheet separated from the surface of the photosensitive member to a fixing unit, a blowing unit is provided opposite to the conveying unit, and the conveying unit is directed toward the sheet being conveyed. By suppressing the floating of the paper from the conveying means by blowing from the blowing means (Patent Document 1),
In a paper transport device that transports paper in a transport path formed by upper and lower guide plates, air ducts that open in the transport path are placed at the joints of multiple guide plates that extend horizontally on the same side of the paper Sheet transport device (Patent Document 2),
An ink jet recording apparatus in which suction holes are provided on the outer peripheral surface of the paper discharge driving roller, and suction is performed from the back surface of the paper during the discharge operation to form a cockling state with a constant period on the paper (Patent Document 3).
Etc. were proposed.
JP-A-11-295947 JP 2004-67321 A JP 2003-191552 A

  However, if air is blown on the recording medium being transported by the transport means, curling upward of the paper can be suppressed, but the effect of suppressing the lifting of the recording medium caused by the recording head in the ink jet recording apparatus is effective. Absent.

  Further, the paper conveyance device described in Patent Document 2 is limited to a paper conveyance device having a conveyance path formed by upper and lower guide plates.

  Furthermore, in a configuration in which suction holes are provided on the outer peripheral surface of the paper discharge drive roller and suction is performed from the back side of the paper during the paper discharge operation, the recording medium is stable to the paper discharge drive roller when an upward curl occurs in the print medium. There is a problem in that the sheet cannot be contacted and the sheet floats at the recording head, resulting in a decrease in print quality.

  The present invention has been made to solve the above-described problem. Even when water-based ink is used, the influence of curling generated on the recording medium due to the adhesion of the ink is suppressed, and the recording medium under the recording head is An object of the present invention is to provide an ink jet recording apparatus which can achieve good print quality by suppressing lifting and can stably guide the recording medium to a downstream discharge section.

  According to a first aspect of the present invention, there is provided a transport conveyor that transports a recording medium in a certain direction, a recording head that records an image by ejecting ink toward the recording medium transported by the transport conveyor, Discharging means that is provided adjacent to the downstream side and separates and discharges the recording medium on which an image is recorded by the recording head from the conveyor, and an air ejection guide member that blows an air flow toward the conveyor The air ejection guide member has a first ejection hole that blows an air flow upstream of the discharge side roller located at the downstream end of the transport conveyor and downstream of the recording head. The present invention relates to an ink jet recording apparatus.

  In the ink jet recording apparatus, even when a downward curl occurs in a recording medium such as a recording sheet by recording an image in the recording head, the air flow blown out from the first ejection hole of the air ejection guide member Since the recording medium is pressed by the conveyor, the recording medium can be effectively prevented from being lifted due to the downward curl. Therefore, good print quality can be achieved, and the recording medium can be reliably sent out toward the discharge means.

  As the recording medium, in addition to the recording paper, various plastic films and fabrics can be used.

  The ink may be any ink as long as it is used in an inkjet recording apparatus, and an organic solvent-based ink is also used in addition to a water-based ink.

  The invention according to claim 2 relates to the ink jet recording apparatus according to claim 1, wherein the air ejection guide member includes a second ejection hole for ejecting air toward the discharge means.

  In the ink jet recording apparatus, since the air flow is blown out from the second ejection hole toward the discharge means, the recording medium sent from the conveyor to the discharge means is an air flow ejected from the first ejection hole. In addition to being pressed by the conveyor, it is pressed by the discharge means by the air flow from the second ejection hole. Therefore, even if the recording medium is curled downward, it is stably conveyed not only by the conveyor but also by the discharging means.

  According to a third aspect of the present invention, the air ejection direction in the second ejection hole is set to form an angle of 30 to 80 degrees with respect to a plane perpendicular to the recording medium ejection path in the ejection means. The present invention relates to an ink jet recording apparatus according to claim 2.

  In the ink jet recording apparatus, the recording medium is particularly effectively pressed by the conveyor and the discharging unit. Therefore, even when the recording medium is curled downward, the conveying conveyor and the discharging unit are particularly stable. Be transported.

  According to a fourth aspect of the present invention, in the ink jet recording according to the second or third aspect, a length of a portion provided with the first ejection hole and the second ejection hole in the air ejection guide member is larger than a width of the recording medium. Relates to the device.

  In the ink jet recording apparatus, since the air flow ejected from the first ejection hole and the second ejection hole hits the entire width of the recording medium, not only the central portion but also the side edge portion of the recording medium is transported and discharged. Pressed.

  A fifth aspect of the present invention relates to the ink jet recording apparatus according to the fourth aspect, wherein a plurality of the first ejection holes and the second ejection holes are provided along a longitudinal direction of the air ejection guide member.

  In the ink jet recording apparatus, by appropriately setting the lengths and intervals of the first ejection holes and the second ejection holes, the strength of the air flow is made uniform over the entire width of the air ejection guide. Can do.

  Accordingly, since both the central portion and the side edge portion of the recording medium are evenly pressed by the conveyor and the discharging means, particularly high printing quality can be obtained, and the recording medium can be stably conveyed.

  As described above, according to the present invention, it is possible to achieve the good print quality by suppressing the influence of the curl generated in the recording medium due to the adhesion of the ink and suppressing the floating of the recording medium below the recording head. An ink jet recording apparatus capable of stably guiding the recording medium to a downstream discharge unit is provided.

1. Embodiment 1
An example of the ink jet recording apparatus according to the present invention will be described below.

  As shown in FIGS. 1 and 2, the inkjet recording apparatus 12 according to the first embodiment is provided with a housing 14, a paper feed tray 16 that is provided at the bottom of the housing 14, and supplies paper P, and a paper feed tray. 16 includes an image recording unit 30 that records an image on the paper P supplied from 16, and a paper discharge tray 46 from which the paper P on which an image is recorded by the image recording unit 30 is discharged. The paper P is an example of a recording medium in the present invention.

  Between the image recording unit 30 and the paper feed tray 16, a group of paper feed roller pairs 20 for conveying the paper P along a predetermined paper feed path 22 is provided. A group of paper discharge roller pairs 42 for conveying the paper P along a predetermined paper discharge path 44 is provided between the two. In addition, a pickup roller 18 that takes out the paper P one by one is provided between the pair of paper feed rollers 20 on the most upstream side and the paper feed tray 16.

  Adjacent to the downstream side of the image recording unit 30 is a paper discharge unit 60 that sends out the paper P on which an image has been recorded by the image recording unit 30 toward the paper discharge path 44. A direction changing roller 48 that guides the paper P that has passed through the paper discharge unit 60 toward the paper discharge path 44 is provided downstream of the paper discharge unit 60.

  Between the image recording unit 30 and the paper feed tray 16, an image is recorded on the upper surface of the image recording unit 30, and the paper P sent to the paper discharge path 44 is imaged along the transport path 52. A group of roller pairs 50 returning to the entrance of the recording unit 30 is provided.

  As shown in FIGS. 1 to 3, the image recording unit 30 includes a recording head including four recording heads 32 corresponding to yellow (Y), magenta (M), cyan (C), and black (K) colors. The conveyance belt 28 that conveys the recording paper P so as to pass through the array 31 and the ejection region SE where ink is ejected from the four recording heads 32, and the driving roller 24 and the driven roller 26 on which the conveyance belt 28 is stretched. With. The conveyance belt 28 corresponds to the conveyance conveyor in the present invention.

  On both sides of the recording head array 31, four maintenance units 34 that perform maintenance operations on the recording heads 32 are disposed so as to correspond to the recording heads 32. At the time of maintenance, as shown in FIG. 2, the recording head array 31 moves upward, and the maintenance unit 34 moves into a gap formed between the conveyance belt 28 and enters. Then, a predetermined maintenance operation (suction, dummy jet, wiping, capping, etc.) is performed while facing the nozzle surface 32N of the recording head 32.

  Above the recording head array 31, four ink tanks 54 for supplying ink to the recording heads 32 are provided, one for each recording head 32.

  A charging roller 36 is disposed on the upstream side of the recording head array 31. The charging roller 36 takes one of pressing and separation, and is driven while sandwiching the conveying belt 28 and the paper P between the driven roller 26 and pressing the paper P against the conveying belt 28 at the pressing position. Thus, the sheet P is electrostatically attracted onto the conveyance belt 28. Reference numeral 38 denotes a power source for charging the charging roller 36.

  The paper discharge unit 60 corresponds to the discharge means in the present invention, and as shown in FIG. 3, a suction conveyor 64 that discharges the paper P, and a suction fan 66 that sucks air and generates a suction force in the suction conveyor 64. The tubular air jet guide member 62 positioned above the driving roller 24, and the sheet P on which the image is recorded by the recording head array 31 is peeled off from the conveying belt 28, which is located between the suction conveyor 64 and the conveying belt 28. The peeling claw 68 is provided.

  The air ejection guide member 62 is a tubular member disposed horizontally along a direction orthogonal to the conveyance direction of the paper P, and the air flow guides toward the portion of the conveyance belt 28 that is wound around the drive roller. And a second ejection hole 63 for ejecting an air flow toward the peeling claw 68 in the paper discharge unit 60. As shown in FIG. 4, the first ejection hole 61 and the second ejection hole 63 are slit-like openings that open along the longitudinal direction of the air ejection guide member 62, and are 5 at regular intervals along the longitudinal direction. One is provided. The number of the first ejection holes 61 and the second ejection holes 63 is not limited to five. Further, the length of the portion of the air ejection guide member 62 where the first ejection holes 61 and the second ejection holes 63 are provided is larger than the width of the paper P. Further, as shown in FIG. 3, the second ejection hole 63 includes an air flow ejected from the second ejection hole 63 and a P transport path t for the paper discharge unit 60 indicated by a two-dot chain line in FIG. 3. It is preferable that the formed angle θ is 30 to 80 degrees. The first ejection holes are formed so as to blow air in a direction perpendicular to the conveyance direction of the paper P in the conveyance belt 28.

  Hereinafter, the operation of the inkjet recording apparatus 12 will be described.

  As described above, at the time of image formation, the maintenance unit 34 moves to both sides of the recording head array 31, and the recording head array 31 comes close to the conveyance belt 28.

  The paper P is picked up one by one from the paper feed tray 16 by the pickup roller 18 and sent to the paper feed roller pair 20. Then, it is inserted into the image recording unit 30 through the paper feed path 22.

  The paper P is transported in the ejection area SE by the transport belt 28 in the image recording unit 30, and simultaneously, Y, M, C, and K inks are ejected from each recording head 32, and a full color image is formed on the upper surface of the paper P. To be recorded.

  The paper P on which the full-color image is recorded is peeled off from the conveying belt 28 by the peeling claw 68 and introduced into the suction conveyor 64, and is introduced into the paper discharge path 44 by the direction changing roller 48. Then, the paper is conveyed toward the paper discharge tray 46 along the paper discharge path 44 by the paper discharge roller pair 42.

  Here, when water-based ink is used in the image recording unit 30, as indicated by a two-dot chain line in FIGS. 5 and 6, the upper surface of the paper P, that is, the surface on which ink is attached, extends and the paper P faces downward. Try to curl.

  However, as indicated by the solid line in FIG. 5, the sheet P that has passed through the recording head array 31 is pressed flat against the transport belt 28 by the air flow ejected from the first ejection holes 61 provided in the air ejection guide member 62. Therefore, it is stably conveyed toward the paper discharge unit 60.

  Then, the recording paper P discharged to the paper discharge unit 60 is pressed toward the peeling claw 68 and the suction conveyor 64 by the air flow from the second ejection holes 63 as shown by a solid line in FIG. Can be transported stably.

  As described above, in the ink jet recording apparatus 12 according to the first embodiment, even when the water-based ink is used in the recording head 32, the paper P that has passed through the recording head array 31 is the first ejection hole of the air ejection guide member 62. Since the air flow blown from 61 presses the conveying belt 28, the sheet P does not rise due to downward curling. Therefore, since the paper P and the nozzle surface 32N of the recording head 32 are not rubbed, unnecessary ink adheres to the paper P and the image surface is not stained, and good print quality can be achieved. Further, after the paper P passes through the conveying belt 28, the paper P is pressed against the peeling claw 68 and the suction conveyor 64 by the air flow blown out from the second jet hole 63 of the air jet guide member 62. As a result, the leading edge of the paper P is not lifted up to cause a conveyance failure.

FIG. 1 is a schematic diagram illustrating an arrangement of each component during image formation of the ink jet recording apparatus according to the first embodiment. FIG. 2 is a schematic diagram illustrating the arrangement of each component during cleaning of the ink jet recording apparatus according to the first embodiment. FIG. 3 is an enlarged view showing details of the configuration of the image recording unit and the paper discharge unit in the ink jet recording apparatus according to the first embodiment. FIG. 4 is an enlarged view showing the shape and arrangement of the first ejection holes 61 and the second ejection holes 63 provided in the air ejection guide member 62 of the ink jet recording apparatus according to the first embodiment. FIG. 5 is a partially enlarged view showing a state in which the paper P that has passed through the recording head array 31 is pressed against the conveyance belt 28 by the air flow from the first ejection holes 61 of the air ejection guide member 62. FIG. 6 is a partially enlarged view showing a state in which the sheet P that has passed through the conveying belt 28 is pressed against the peeling claw 68 and the suction conveyor 94 by the air flow from the second ejection hole 63 of the air ejection guide member 62. .

Explanation of symbols

12 Inkjet recording device 28 Conveying belt 30 Image recording unit 31 Recording head array 32N Nozzle surface 32 Recording head 34 Maintenance unit 36 Charging roller 60 Paper discharge unit 62 Air ejection guide 64 Pulling conveyor 66 Suction fan 68 Peeling claw

Claims (5)

A transport conveyor for transporting the recording medium in a certain direction;
A recording head for recording an image by discharging ink toward a recording medium conveyed by the conveying conveyor;
Discharging means that is provided adjacent to the downstream side of the conveyer and separates and ejects the recording medium on which an image is recorded by the recording head from the conveyer;
An air ejection guide member that blows an air flow toward the conveyor,
The air ejection guide member has a first ejection hole that blows an air flow upstream of the discharge roller positioned at the downstream end of the transport conveyor and downstream of the recording head. An ink jet recording apparatus.   2. The ink jet recording apparatus according to claim 1, wherein the air ejection guide member includes a second ejection hole that ejects air toward the ejection unit.   3. The inkjet recording according to claim 2, wherein an air ejection direction in the second ejection hole is set to form an angle of 30 to 80 degrees with respect to a plane perpendicular to a recording medium ejection path in the ejection unit. apparatus.   4. The inkjet recording apparatus according to claim 2, wherein a length of a portion of the air ejection guide member provided with the first ejection hole and the second ejection hole is larger than a width of the recording medium.   The inkjet recording apparatus according to claim 4, wherein a plurality of the first ejection holes and the second ejection holes are provided along a longitudinal direction of the air ejection guide member.

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