JP2007144710A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent an image quality by a recording head from decreasing due to excessive dropping of a sheet into an ink mist suction hole formed in a platen in preparation for frameless printing in an inkjet recorder, and to effectively collect ink mist and the like. <P>SOLUTION: The sheet P is prevented from being sucked to drop in the ink mist suction hole 25 formed in preparation for frameless printing in the platen 22. A part of ink becomes ink mist and floats in the air when the ink is ejected even to an external region of the sheet when frameless printing is carried out. A supporting projection 26b is set in the ink mist suction hole 25 which sucks the ink mist, whereby the excessive suction and dropping of the sheet P into the ink mist suction hole 25 is supported from below. The sheet P is always held with a constant distance to a recording head 3, so that the image quality can be maintained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus as an image forming system.

  In an ink jet recording apparatus, when ink is ejected to a sheet as a recording medium in order to perform stable and high quality recording, it is required to prevent as much as possible so-called cockling in which a swollen portion is generated in the sheet due to ink absorption. It is done. In addition, for a sheet that is curled up due to moisture or the like, the sheet lift from the platen in the direction of the recording head is prevented, and the distance between the sheet surface and the recording head is always kept constant and favorable. There is a need. In other words, when the sheet is lifted, there is a problem that parts or devices provided in the vicinity of the recording head or the recording unit come into contact with and rub against the lifted part of the sheet to damage or stain the sheet.

  In order to prevent sheet lifting due to cockling or the like, a paper pressing mechanism for an ink jet printer has been proposed in which an upstream portion in the sheet conveyance direction is pressed against a platen by a sheet pressing member (see Patent Document 1). There has also been proposed an apparatus in which a large number of suction holes are provided in the platen so that the sheet is adsorbed to the platen by a suction force due to negative pressure (see Patent Documents 2 and 3).

JP-A-4-69264 JP-A-61-95966 Japanese Utility Model Publication No. 3-29352

  Incidentally, one type of printing on the sheet surface is borderless printing in which no margin is provided around the sheet. In borderless printing, it is necessary to eject ink over a wider range than the sheet width. Ink ejected over a wider area may spread to the outer area of the sheet, and a part of the ink is absorbed and collected by a special absorbent sheet, but some of the ink floats in the air as ink mist To do. In order to suck and collect the ink mist floating in the air with a negative pressure, suction holes are provided in the platen at positions corresponding to various sheet sizes.

  For example, during borderless printing on a large A3 size sheet, the borderless printing suction hole corresponding to a small A4 size sheet is hidden behind the A3 size sheet. It does not support directly. Therefore, during the suction operation by the suction fan, the sheet to be expanded by absorbing the ink excessively falls into the borderless printing suction hole corresponding to the A4 size and deforms into a concave shape with respect to the other platen transport surface. Due to the concave deformation of the sheet, there is a problem that the distance from the recording head is increased and recording accuracy is lowered.

  There is no means for solving such a problem in any of the sheet lifting prevention means disclosed in the above publication.

  It is an object of the present invention to effectively prevent a sheet from dropping excessively into an ink mist suction hole provided in a platen in preparation for borderless printing and degrading image quality by a recording head, and effectively recovering ink mist and the like. An object of the present invention is to provide an ink jet recording apparatus that can be used.

  In order to achieve the above object, a typical ink jet recording apparatus according to the present invention has a platen disposed opposite to a recording head for recording by discharging ink onto a sheet, and the sheet has been conveyed to the platen. The platen is provided with a sheet suction hole for sucking and holding the ink, and an ink mist suction hole for sucking and collecting the ink mist discharged to the outer area of the sheet in preparation for borderless printing. According to another aspect of the present invention, a support protrusion that protrudes from the ink mist suction hole is provided to prevent the sheet from being excessively sucked into the ink mist suction hole by supporting the sheet from below.

  According to the ink jet recording apparatus of the present invention, it is effective to prevent the sheet from being sucked into the ink mist suction hole provided in preparation for borderless printing on the platen. That is, in order to prevent ink mist from floating in the air by ejecting ink to the outer area of the sheet during borderless printing, an ink mist suction hole is provided in the platen for borderless printing. The sheet is excessively sucked into the ink mist suction hole, and the sheet is moved away from the recording head, thereby degrading the image quality. In order to prevent this, by supporting the sheet from below by protruding it into the ink mist suction hole and supporting the sheet from below, the distance from the recording head can be kept constant and image quality can be maintained without excessively falling the sheet. Can do.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an ink jet recording apparatus as an image forming system according to the invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, the apparatus main body 1 of the ink jet recording apparatus according to the present embodiment includes the following members and devices arranged in the conveyance direction of a sheet P that is a recording medium conveyed from the sheet feeding apparatus. Has been. The image recording unit 3a, the paper discharge roller 11a, and the paper discharge spur 11b are sequentially arranged, and the conveyance roller 9 and the pinch roller 12 convey the sheet P from the sheet conveyance path to the image recording unit 3a. The paper discharge roller 11a and the paper discharge spur 11b discharge the sheet P on which image formation has been completed in the image recording unit 3a to the outside of the apparatus.

  The image recording unit 3 a includes a platen 22 that supports the sheet P that is nipped and conveyed by the conveying roller 9 and the pinch roller 12. A carriage 2 that moves in the scanning direction facing the platen 22 is disposed. The carriage 2 includes a recording head 3 that performs recording by discharging ink onto the sheet P on the platen 22. Both ends of the carriage 2 are fixed to the frame 6 of the apparatus main body 1 and slidably supported by a guide shaft 7 and a guide rail 8 which are parallel to each other. The carriage 2 is guided by a drive source motor and a belt drive device (both not shown). It reciprocates along the shaft 7 and the guide rail 8.

  The recording head 3 includes a plurality of nozzles (not shown) in which a plurality of inks are ejected on the surface facing the sheet P. These nozzle groups are arranged in the sub-scanning direction and eject different colors of ink for each nozzle. The corresponding color ink is supplied from the ink tank 4 to the nozzles of the respective colors via the supply tubes 5.

  Further, the sheet storage unit 10 is covered with the cassette cover 13 with the apparatus main body 1 equipped with the sheet feeding device, and the cassette cover 13 is opened when the sheet P is replenished or replaced in the sheet storage unit 10.

  Therefore, when the image recording operation is started, the paper feed roller 15 comes into contact with the uppermost sheet P1 of the sheets P stacked on the sheet storage unit 10 by the downward rotation of the arm 14 and the weight of the paper feed roller 15. Is done. When the sheet feeding roller 15 rotates in this state, the sheet P1 is conveyed, separated by receiving a resistance force in the separation plate 19, and conveyed to the roller guide 20 along the slope of the separation plate 19. The sheet P1 conveyed to the roller guide 20 enters the sheet conveyance path R, is guided to the positions of the conveyance roller 9 and the pinch roller 12 by the rotation of the U-turn roller 21, and is sandwiched between the conveyance roller 9 and the pinch roller 12. It is conveyed to a recording position on the platen 23.

  When the sheet P1 is conveyed to the recording position, a printing (image recording) operation by the recording head 3 mounted on the carrier 2 is subsequently started. In this printing operation, for example, when printing for one scan by the recording head 3 is completed, the printing operation is temporarily stopped, the sheet P1 on the platen 23 is conveyed by a predetermined amount by the conveying roller 9, and then the carrier 2 is moved again. Printing is performed according to the procedure of performing printing for the next one scanning while moving along the guide shaft 7. In this way, a desired image is recorded on the sheet 2 by ejecting ink from the recording head 3 toward the sheet P1 while moving the carrier 2 back and forth. After the printing operation is completed, the sheet P1 on which a desired image is recorded is sandwiched between the paper discharge roller 11a and the paper discharge spur 11b and discharged onto the cassette cover 13.

  Although the description has been given of the sheet feeding from the cassette, the borderless printing mechanism having the same platen shape can be configured even when the roll sheet is fed when the roll sheet is installed.

(First embodiment)
Here, as shown in FIGS. 3A and 3B and FIG. 4, the platen 22 which is a main part is provided with a large number of sheet suction holes 23, and air is sucked from the sheet suction holes 23 and the sheet is sucked. A suction fan (first electric fan) 24 for adsorbing and holding P is provided. The suction fan 24 is rotated by a fan motor (not shown) to create a negative pressure inside the platen main body, and sucks and holds the sheet P conveyed on the platen 22 with the negative pressure.

  Further, the platen 22 is provided with a recess 25a for collecting ink ejected to the outside of the sheet during borderless printing. The recess 25 a has an opening area having a considerably large size as the ink mist suction hole 25 on the surface of the platen 22. When borderless printing is performed, the ink is ejected to the outer area of the sheet P. Since a part of the ink discharged to the outer area of the sheet becomes an ink mist floating in the air, an ink mist suction hole 25 is provided for the purpose of sucking and collecting the ink mist. However, there is a concern that the end portion of the sheet P is sucked into the ink mist suction hole 25 and falls excessively. If the sheet is excessively dropped, the distance from the recording head 3 is long, and the image quality may be deteriorated. In order to prevent this, the ink mist suction hole 25 is provided with a later-described support protrusion 27 which is effective for simplicity. The following is related to the surrounding structure.

  An ink absorbing sheet 26a for the purpose of absorbing ink (excluding ink mist) discharged to the outer area of the sheet in the platen main body immediately below the ink mist suction hole 25 is provided in the storage partition wall 26 which is the inner wall of the recess 25a. It is stored. In addition, an ink mist collection hole 26b is provided in a part of the storage partition wall 26, and when a part of the ink ejected to the outer region of the sheet P floats in the air as an ink mist during borderless printing, it is sucked into the suction fan. 24 is operated and suctioned by the negative pressure by the outside air suction, and is recovered from the ink mist recovery hole 26b.

However, at the time of recovery by such ink mist suction, the end portion of the sheet P is excessively sucked into the ink mist suction hole 25 due to negative pressure and tends to fall. In order to prevent this, a support protrusion 27 projects from the ink mist suction hole 25 to support the sheet P about to fall from below. As a position where the support protrusion 27 protrudes from the ink mist suction hole 25,
It is effective to be upstream in the sheet conveying direction.

  The ink mist suction holes 25 are provided by being opened at positions corresponding to various sheet sizes. For example, when an A3 size sheet is being conveyed, the ink mist suction hole 25 corresponding to the A4 size having a small sheet size is located immediately below the A3 size sheet, and the sheet is not directly supported by the platen 22. Therefore, as described above, the sheet P that is to be expanded by absorbing the ink excessively falls into the ink mist suction hole 25 corresponding to the A4 size sucked by the suction fan 24, and against the other platen transport surface. As a result, the distance between the recording head 3 and the sheet P increases and the recording accuracy decreases. In the present embodiment, in order to avoid such a problem, a convex support protrusion 27 is provided on the upstream side of the ink mist suction hole 25 to prevent the sheet P from excessively falling into the ink mist suction hole 25.

  FIG. 4 shows a positional relationship between the sheet P and the ink mist suction hole 25 for A4 borderless printing when, for example, an A4 size sheet P is being conveyed. Usually, in order to avoid the sheet P from interfering with the recording head 3, the edge of the sheet P is lowered, but the ink mist hole 25 for borderless printing is sucked by the suction fan 24. Unless applied, the edge of the sheet falls into the suction hole 25 for borderless printing and is far from the recording head 3. Therefore, it is also possible to prevent the sheet end portion from excessively falling into the ink mist suction hole 25 by being supported from below by a convex support protrusion 27 provided on the upstream side of the ink mist suction hole 25.

(Second Embodiment)
FIG. 5 shows a second embodiment. In the case of the present embodiment, a dedicated suction fan (second electric fan) 28 for collecting ink mist is used to suck the ink mist of a component in which part of the ink ejected to the outer area of the sheet at the time of borderless printing floats in the air. Are provided independently. That is, the suction fan 28 is provided separately from the suction fan 24 for sucking and holding the sheet P shown in the first embodiment.

  Therefore, in the second embodiment, the suction fan 24 for sucking and holding the sheet P and the suction fan 28 for collecting the ink mist are provided independently, thereby further improving the suction efficiency and the collection effect of each. It is a thing.

  Each embodiment has been described above, but other embodiments, application examples, modified examples, and combinations thereof are possible within the scope not departing from the gist of the present invention. The structures illustrated as the first and second embodiments are examples, and are not limited to the illustrated shapes.

1 is a perspective view showing an ink jet recording apparatus equipped with a platen according to an embodiment. FIG. 3 is a side sectional view of the ink jet recording apparatus. (A), (b) is the perspective view and principal part sectional drawing which show the platen of 1st Embodiment. The principal part sectional drawing of the platen which similarly shows engagement with the sheet | seat at the time of borderless printing in 1st Embodiment. Sectional drawing which shows the principal part of the platen in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 1A Device main body 22 Platen 23 Sheet suction hole 24 Suction fan (first electric fan)
25 Ink Mist Suction Hole 26 Ink Absorbing Sheet 26b Ink Mist Collection Hole 27 Supporting Projection 28 Suction Fan for Collecting Ink Mist (Second Electric Fan)
P sheet (recording medium)

Claims (6)

A platen disposed opposite to a recording head that discharges and records ink on the sheet, and has a sheet suction hole in the platen to suck and hold the sheet conveyed to the platen; and In an ink jet recording apparatus provided with an ink mist suction hole for sucking and collecting ink mist by ink discharged to the outer area of the sheet in preparation for borderless printing,
An ink jet recording apparatus, comprising: a support protrusion that protrudes from the ink mist suction hole to prevent the sheet from being excessively sucked into the ink mist suction hole by supporting the sheet from below.   2. The platen according to claim 1, wherein the platen is provided with a first electric fan for sucking air from the sheet suction hole to generate a negative pressure and sucking and collecting the ink mist. Inkjet recording device.   The inkjet recording apparatus according to claim 1, wherein a dedicated second electric fan for sucking and collecting the ink mist is provided. In an inkjet recording apparatus that records on a recording medium using a recording head that ejects ink,
A platen that supports a recording medium at a position facing the recording head;
An adsorption hole formed in the platen for adsorbing the recording medium to the platen by negative pressure;
A recess provided in the platen for collecting ink ejected to the outside of the recording medium;
An ink mist collecting hole that is formed in the recess and collects the ink mist by negative pressure;
A support protrusion for supporting the recording medium to prevent the recording medium from entering the recess,
An ink jet recording apparatus comprising:   The inkjet recording apparatus according to claim 4, wherein the support protrusion protrudes so as to extend downstream from an upstream edge of the recess in a recording medium conveyance direction.   The ink jet recording apparatus according to claim 4, wherein the ink mist collection hole is provided in an inner wall of the recess.

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