JP2014177044A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which skew cannot be suppressed with simple constitution without increasing a transport load.SOLUTION: A transport roller 23 has one end part held by a bearing part 211, an intermediate part held by a bearing part 212, and the other end part held by a bearing part 213 respectively rotatably, and the bearing parts 211-213 are eccentric bearings and can move the transport roller 23 in a transport direction. The bearing part 213 is rotated to move an end center position of the transport roller 23 to an upstream side in the transport direction, and the transport roller 23 is arranged such that a part closer to its center from the bearing parts 212, 213 at end parts projects to a downstream side in the transport direction.

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Some image forming apparatuses such as printers, copying apparatuses, plotters, and complex machines using a long roll-shaped print medium (hereinafter also referred to as “roll paper”) wound in a roll shape.

  In such an image forming apparatus, it is necessary to prevent wrinkles and twists due to skew that is conveyed while the roll paper is inclined.

  Therefore, conventionally, a guide that forms a conveyance path for the roll-shaped recording paper, and a curved line that extends along the guide and extends in the width direction of the recording paper and that has a leading end directed toward the surface of the roll-shaped recording paper. There has been known one in which a curl removing member is provided so that the arcuate apex is in contact with the central portion of the roll-shaped recording paper surface to be conveyed (Patent Document 1).

Japanese Patent No. 2738754

  However, when the curl removing member that contacts the surface of the roll-shaped print medium conveyed as described above is disposed, the print medium does not move in the width direction when the width of the roll-shaped print medium becomes wide. There is a problem that the skew cannot be reduced.

  In this case, it may be possible to use a conveyance roller having a drum-shaped peripheral surface. However, it is difficult to manufacture such a drum-shaped conveyance roller with high accuracy, and there is a problem that the cost increases.

  The present invention has been made in view of the above problems, and an object thereof is to reduce the skew of a printing medium with a simple configuration.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A rotating body that rotates in contact with the print medium;
The shaft portion of the rotating body protrudes from the center rather than the end portion toward the downstream side in the print medium conveyance direction.

  According to the present invention, the skew of the print medium can be reduced with a simple configuration.

1 is an external perspective view illustrating an example of an image forming apparatus according to the present invention. 2 is a schematic side view of the apparatus. FIG. 2 is an explanatory plan view of a main part of an image forming unit of the apparatus. FIG. It is a typical plane explanatory view of a conveyance roller part used for explanation of arrangement of a conveyance roller. It is explanatory drawing of the bearing part of a conveyance roller similarly. It is a plane explanatory view explaining the shape of a conveyance roller similarly. It is a plane explanatory view explaining the shape of a conveyance roller in the state where the projection position of a conveyance roller was changed similarly. FIG. 6 is a schematic plan view for explaining an example in which a bearing of a conveyance roller is disposed in a conveyance region. It is explanatory drawing with which it uses for description of the other example of a bearing part.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of an image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the image forming apparatus, FIG. 2 is a schematic side view of the image forming apparatus, and FIG.

  This image forming apparatus is a serial type image forming apparatus, and includes an apparatus main body 101 and a paper feeding device 102 disposed below the apparatus main body 101.

  Inside the apparatus main body 101, a guide rod 1 and a guide stay 2, which are guide members, are stretched over both side plates (not shown). The guide rod 1 and the guide stay 2 hold the carriage 5 so as to be movable in the direction of arrow A in FIG. 1 (main scanning direction in FIG. 3).

  The carriage 5 is reciprocated in the main scanning direction by the main scanning motor 6 via the driving pulley 7, the driven pulley 8 and the timing belt 9.

  The carriage 5 includes a plurality of (here, five) liquid discharge heads that discharge ink droplets and recording heads 11a to 11e in which a head tank that supplies liquid to the liquid discharge heads is integrated (if not distinguished, “recording” Head 11 ”). The recording heads 11a and 11b are held by the head holder 51A, and the recording heads 11c to 11d are held by the head holder 51A.

  Here, the recording head 11a and the recording heads 11b to 11e are arranged by shifting the position of one head (one nozzle row) in the sub-scanning direction that is a direction orthogonal to the main scanning direction. Each of the recording heads 11a to 11e has two nozzle rows. The recording heads 11a and 11b discharge black droplets having the same color, and the recording heads 11c to 11e discharge magenta (M), cyan (C), and yellow (Y) droplets, respectively.

  As a result, monochrome images can be formed with a width of two heads in one scan (main scan) using the recording heads 11a and 11b, and color images are formed using, for example, the recording heads 11b to 11e. be able to. The head configuration is not limited to this, and a plurality of recording heads may be arranged side by side in the main scanning direction.

  Ink of each color is supplied to the head tank of the recording head 11 via a supply tube 16 that can be bent from ink cartridges 10k, 10c, 10m, and 10y, which are main tanks that are replaceably attached to the apparatus main body 101. Is done. At this time, ink is supplied from one ink cartridge 10k to the two recording heads 11a and 11b that discharge droplets of the same color.

  On the other hand, in the recording area of the main scanning area of the carriage 5, the roll paper 120 is fed from the paper supply device 102, and a direction perpendicular to the main scanning direction of the carriage 5 by the conveying means 21 (sub-scanning direction: arrow B direction). ) Intermittently.

  The transport unit 21 includes a transport roller 23 that is a rotating body that transports the roll paper 120 that is a roll-shaped medium fed from the paper feeder 102, and a pressure roller 24 that is disposed opposite the transport roller 23. And it has the conveyance guide member 25 in which the several suction hole was formed, and the suction fan 26 as a suction means which performs suction from the suction hole of the conveyance guide member 25. FIG.

  A cutter 27 serving as a cutting unit that cuts the roll paper 120 on which the image is formed by the recording head 11 at a predetermined length is disposed on the downstream side of the transport unit 21.

  The cutter 27 is attached to a wire or a timing belt 28, for example. The timing belt 28 is wound around a driving pulley driven by a driving motor (not shown) and a driven pulley, and the timing belt 28 is moved in the main scanning direction A by the driving motor via the driving pulley. 27, the paper is cut into a predetermined length.

  Further, on one side of the carriage 5 in the main scanning direction, a maintenance / recovery mechanism 30 that performs maintenance / recovery of the recording head 11 is disposed on the side of the conveyance guide member 25. In addition, on the other side in the main scanning direction, idle discharge receptacles 34 that perform idle ejection for ejecting liquid droplets that do not contribute to image formation from the recording head 11 are respectively disposed on the side of the conveyance guide member 25.

  The maintenance / recovery mechanism 30 includes a first maintenance / recovery unit 31 held by the frame member of the apparatus main body 101, and a second maintenance / recovery unit 32 held by the frame member of the maintenance / recovery mechanism 30 so as to be capable of reciprocating in the sub-scanning direction. have. The second maintenance / recovery unit 32 is at the position shown in FIG. 3 when performing the maintenance / recovery of the recording head 11a, and moves to the same sub-scanning direction position as the first maintenance / recovery unit 31 when performing the maintenance / recovery of the recording heads 11b to 11e.

  The maintenance / recovery mechanism 30 includes, for example, a suction cap 41 and a moisturizing cap 42 that also serve as a moisturizing cap for capping the nozzle surface (surface on which the nozzle is formed) of the recording head 11, a wiper member 43 for wiping the nozzle surface, and image formation. And a blank discharge receiver 44 for receiving droplets (empty discharge droplets) that do not contribute to.

  The paper feeder 102 has a spool bearing base 111. Inside the spool bearing base 111, there is provided a feeding mechanism that feeds the roll paper 120 from the roll body 112 and rewinds the roll paper 120.

  The roll body 112 is obtained by winding a sheet (hereinafter referred to as “roll paper”) 120 which is a long roll-shaped medium around a tube 114 which is a core member in a roll shape. Note that the roll body is a general term for members including the tube 114 and the roll paper 120.

  Then, the roll body 112 mounted on the spool bearing base 111 is rotated to feed the roll paper 120 downstream along the guide member 130.

  On the downstream side of the spool bearing base 111 in the feed direction, a pair of transport rollers 131 that curves and feeds the roll paper 120 fed from the roll body 112 is disposed. A guide member 130 that guides the lower surface of the roll paper 120 is disposed between the spool bearing base 111 and the conveying roller pair 131.

  By rotating the conveyance roller pair 131, the roll paper 120 fed out from the roll body 112 is conveyed by the conveyance roller pair 131, passes through the conveyance roller pair 131, and the conveyance roller 23 and the pressure roller 24 of the conveyance unit 21. It is sent in between.

  In the image forming apparatus configured as described above, the recording head 11 is moved while the carriage 5 is moved in the main scanning direction and the roll paper 120 fed from the paper feeding device 102 is intermittently fed by the conveying means 21. A required image is formed on the roll paper 120 by ejecting droplets by driving according to image information (printing information). Then, the roll paper 120 after image formation is cut to a predetermined length by the cutter 27 and discharged to a paper discharge tray (not shown) disposed on the front side of the apparatus main body 101.

  Next, the arrangement of the conveying rollers in this image forming apparatus will be described with reference to FIGS. FIG. 4 is a schematic plan view of the transport roller portion, FIG. 5 is a view of the bearing portion of the transport roller, and FIG. 6 is a plan view of the shape of the transport roller.

  The conveyance roller 23, which is a rotating body that rotates in contact with the roll paper 120, includes a bearing portion 211 provided on the side plate 201, a bearing portion 212 provided on the side plate 202, and a bearing portion 213 provided on the driving side plate 203. It is held rotatably by one bearing.

  Here, the area between the side plates 201 and 202 is an area where the roll paper 120 is conveyed, and the driving side plate 203 is a side plate for attaching a driving system for rotationally driving the conveying roller 23 and the like. In this embodiment, the transport roller 23 is a single roller member having the same diameter, and the transport roller 23 itself is a shaft portion.

  As shown in FIG. 5, the bearing portion 211 that holds one end portion of the transport roller 23 is rotatably supported by a side plate 201 that is a support member. The bearing portion 211 is an eccentric bearing that eccentrically holds the rotation center O1 of the transport roller 23 with respect to the rotation center O2 of the bearing portion 211.

  Further, the bearing portion 211 is formed with a fixing portion 211a for fixing to the side plate 201 with a fastening member, and the fixing portion 211a is formed with a fastening long hole 211b. The fixing portion 211a is fixed to a screw hole 201a provided in the side plate 201 with a screw or the like. The bearing portion 211 is provided with a knob portion 211c.

  In addition, the bearing portion 212 that holds the intermediate portion of the conveying roller 23 and 213 that holds the other end portion of the conveying roller 23 are also configured by eccentric bearings similar to the bearing portion 211 and are supported by the side plates 202 and 203, respectively. Therefore, the description is omitted.

  Thus, by rotating the bearing portions 211 to 213, the portions (holding positions) held by the bearing portions 211 to 213 of the transport roller 23 are in the print medium transport direction (hereinafter simply referred to as “transport direction”). Move along.

  Therefore, as shown in FIG. 6, when the bearing portion 213 is rotated to move the center position of the end portion of the transport roller 23 to the upstream side in the transport direction (in the direction of arrow b), the transport roller 23 is moved to the bearing portions 211 at both ends. , 212 protrudes from the center toward the downstream side in the conveyance direction (arrow a direction).

  At this time, if the bearing portions 211 and 212 are in a state where the rotation centers of the bearing portions 211 and 212 and the rotation center of the transport roller 23 are aligned in the vertical direction, the transport roller 23 is between the bearing portions 211 and 212. It becomes the shape which protruded in the conveyance direction downstream with the middle of the center as a vertex.

  In this case, the deformation amount (bending amount) in the direction along the conveyance direction between the center between the bearing portions 211 and 212 of the conveyance roller 23 and the bearing portions 211 and 212 is about 0.1 to 0.2 mm / 1000 mm. It is preferable that By setting the bending amount within this range, the skew can be reliably suppressed.

  In this way, the conveyance roller 23 protrudes from the center of the end of the print medium in the conveyance direction, so that when the conveyance roller 23 rotates, the outer peripheral surface substantially follows the same locus as the drum-shaped roller. I will draw.

  Accordingly, when the roll paper 120 is conveyed by the conveyance roller 23, the roll paper 120 is conveyed so as to spread from the central portion of the roll paper 120 to the left and right. it can.

  Here, the present invention does not adjust the position of the roll paper by abutting the guide plate convex in the decurling direction (vertical direction) against the roll paper as in the prior art, but the present invention is a roller convex in the direction along the transport direction. Rotates to adjust the position of the roll paper.

  Thus, skew can be suppressed even when the width of the roll paper is widened. On the other hand, it is difficult to move the roll paper in the width direction and the skew cannot be reduced only by striking the roll paper with a guide plate convex in the decurling direction (vertical direction) as in the prior art. .

  Moreover, in the said embodiment, since three places are hold | maintained with the bearing parts 211-213 which are eccentric bearings, the position which protrudes most in the conveyance direction downstream can be changed.

  That is, as shown in FIG. 7, when the bearing portion 211 is also rotated together with the bearing portion 213 and the transport roller 23 is moved upstream in the transport direction (arrow b direction), the position protruding most downstream in the transport direction is It moves from the middle to the bearing portion 213 side (moves from the position of the broken line arrow to the position of the solid line arrow).

  Thereby, the attitude of the transport roller 23 with respect to the skew of the roll paper 120 can be finely adjusted, and the skew can be more reliably suppressed.

  Further, as shown in FIG. 8, a bearing portion 221 that rotatably supports the transport roller 23 in the transport region (between the side plate 201 and the side plate 202) may be provided. The bearing portion 221 in the transport region is preferably provided so as to follow the direction along the transport direction in accordance with the shape of the transport roller 23.

  Further, as shown in FIG. 9, an indication portion 211 d is provided in the bearing portion 211, and a position adjustment scale 215 that serves as a guide for an adjustment amount of the bearing portion 211 corresponding thereto is attached to the side plate 201, whereby the bearing portion 211. The amount of rotation and the amount of forward / backward movement can be understood.

  Moreover, although the said embodiment demonstrated the example which the conveyance roller 23 protruded from the center from the edge part to the conveyance direction downstream, it does not restrict to this.

  For example, of the pair of rotating bodies composed of the conveying roller 23 and the pressure roller 24, the shaft portion of the rotating body (conveying roller 23 or pressure roller 24) having a high friction coefficient on the peripheral surface is located downstream in the conveying direction. It can also be set as the structure which protruded from the center from the edge part.

  Since the shaft portion of the rotating body with the higher friction coefficient protrudes from the center toward the downstream side in the transport direction, the skew suppression effect is increased.

  In addition, both the transport roller 23 and the pressure roller 24 have a configuration in which the shaft portion protrudes from the center to the downstream side in the transport direction, and a rotating body (transport roller 23 having a high friction coefficient on the peripheral surface. Alternatively, the pressure roller 24) can be arranged so that the amount of protrusion toward the downstream side in the transport direction is larger.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics or the like. In addition, “image formation” not only applies an image having a meaning such as a character or a figure to a medium but also applies an image having no meaning such as a pattern to the medium (simply applying a droplet to the medium). It also means to land on.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  In the above-described embodiment, the present invention is applied to an image forming apparatus that uses roll paper. However, the present invention can be similarly applied to an image forming apparatus that uses sheets.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 5 Carriage 11, 11a-11e Recording head 10, 10k, 10c, 10m, 10y Ink cartridge 16, 16A, 16B Supply tube 21 Conveyance means 23 Conveyance roller 24 Pressure roller 25 Platen member 26 Suction means 201, 202 Side plate 203 Drive side plate 211-213 Bearing part 221 Bearing part

Claims (5)

A rotating body that rotates in contact with the print medium;
The image forming apparatus according to claim 1, wherein the shaft portion of the rotating body protrudes from the center rather than the end portion toward the downstream side in the print medium conveyance direction. Having three or more bearing portions that rotatably hold both ends of the shaft portion of the rotating body and an intermediate portion of the shaft portion;
The image forming apparatus according to claim 1, wherein the bearing portion of the intermediate portion holds the shaft portion on the downstream side in the transport direction from the bearing portion of at least one of the end portions. The bearing is rotatably supported by a support member;
The image forming apparatus according to claim 2, wherein a center of the shaft portion is eccentric with respect to a rotation center of the bearing portion. A pair of rotating bodies for conveying the print medium;
4. The shaft portion of a rotating body having a high friction coefficient on the peripheral surface of the pair of rotating bodies protrudes from the center to the downstream side in the print medium conveyance direction from the center. The image forming apparatus according to any one of the above. A pair of rotating bodies for conveying the print medium;
The shafts of the rotating bodies constituting the pair of rotating bodies all protrude from the center rather than the end toward the downstream side in the print medium conveyance direction,
4. The image forming apparatus according to claim 1, wherein the rotating body having a higher friction coefficient on the peripheral surface has a larger amount of protrusion toward the downstream side in the print medium conveyance direction.

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