JP2017007789A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus which improves positioning accuracy of regulation means for regulating an end in the width direction of a sheet in a double-side conveyance path.SOLUTION: An image formation apparatus comprises: a sheet conveyance path which guides a sheet from a cassette (loading means) to discharge means (discharge triple rollers); a double-side conveyance path for conveying the sheet having passed through an image formation unit to the image formation unit again; a regulation member 202 (regulation means) which is provided in the double-side conveyance path and regulates an end in the width direction of the sheet; a skew correction roller pair (skew correction means) which conveys the sheet while making the end of the sheet butt against the regulation member 202 and corrects skew of the sheet; and a core frame 101 (frame member) which has a third guide (conveyance guide) constituting a portion of the sheet conveyance path. The regulation member 202 is attached to the core frame 101.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  In general, in an image forming apparatus such as a copying machine, a printer, or a facsimile, both sides that guide a sheet to the transfer unit again after forming an image on the first side in the transfer unit so that an image can be formed on both sides of the sheet. A device provided with a conveyance path is known. 2. Description of the Related Art Conventionally, an image forming apparatus that conveys a sheet while abutting an end in the width direction of the sheet against a reference plate by a lateral registration correction roller and a skew feeding roller in a double-sided conveyance path has been proposed (see Patent Document 1). The reference plate is provided integrally with a lower conveyance guide that constitutes a part of the double-sided conveyance path, and the skew is corrected by the sheet being conveyed along the reference plate.

Japanese Patent Laid-Open No. 2000-272882

  However, the reference plate described in Patent Document 1 has various parts interposed between the transfer nip to which the sheet is transferred, and there is a problem in positioning accuracy between the reference plate and the transfer nip. Normally, when the sheet is jammed by the double-sided conveyance guide, the lower conveyance guide is opened / closed or removed. Since the reference plate is provided integrally with the conveyance lower guide, there is a possibility that the position of the reference plate is shifted every time the jam processing is performed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that solves the above-described problems by attaching a restricting means to a frame member having a conveyance guide for guiding a sheet to the image forming means.

  The present invention provides an image forming apparatus including a stacking unit on which sheets are stacked, an image forming unit that forms an image on a sheet fed from the stacking unit, and a sheet on which an image is formed by the image forming unit. A discharge unit that discharges the sheet to the outside, a sheet conveyance path that guides the sheet from the stacking unit to the discharge unit, a duplex conveyance path that conveys the sheet that has passed through the image formation unit to the image formation unit, and A regulation unit that is provided in the double-sided conveyance path and regulates an end portion in the width direction of the sheet; and a skew feeding correction unit that feeds the end portion of the sheet while abutting the regulation unit and corrects the skew of the sheet; A frame member having a conveyance guide that constitutes a part of the sheet conveyance path, and the restricting means is attached to the frame member.

  According to the present invention, since the restricting means is attached to the frame member having the conveyance guide that constitutes a part of the sheet conveying path, the tolerance is hardly affected between the restricting means and the image forming means, which is favorable for the sheet. An image can be transferred with positional accuracy.

1 is an overall schematic diagram illustrating a printer according to a first embodiment of the present invention. The perspective view which shows a double-sided conveyance part. The perspective view which shows a control member. (A) is a perspective view which shows a core frame, (b) is an enlarged view which shows the attaching part of a core frame. The perspective view which looked at the core frame from the lower part. It is a perspective view which shows a double-sided conveyance part, Comprising: (a) shows the state which the double-sided conveyance guide closed, (b) shows the state which the double-sided conveyance guide opened. (A) is a perspective view which shows the core frame which concerns on the 2nd Embodiment of this invention, (b) is the expansion perspective view which expanded the dotted-line part of (a). The perspective view which shows the skew feeding roller guide which concerns on the 3rd Embodiment of this invention.

<First Embodiment>
First, a first embodiment of the present invention will be described. The printer 100 (image forming apparatus) according to the first embodiment is an electrophotographic laser beam printer. As shown in FIG. 1, the printer 100 includes a cassette 30 (stacking unit) that can be attached to and pulled out from the printer main body 100A, and an image forming unit 40 (image forming unit) that forms an image on a sheet. doing. In addition, the printer 100 includes a fixing roller pair 104 that fixes an image on a sheet, a discharge triple roller 50 that discharges the sheet to a discharge tray 108, and a duplex conveying unit 20 that forms an image on both sides of the sheet. Have.

  The image forming unit 40 includes a laser scanner (not shown), a process cartridge 42 (image carrier unit) having a photosensitive drum 41 (image carrier), and a transfer roller 103 (transfer member). The process cartridge 42 is configured to be detachable from the printer main body 1A.

  When an image formation command is output to the printer 100, an image forming process by the image forming unit 40 is started based on image information input from an external computer or the like connected to the printer 100. A laser scanner (not shown) irradiates the photosensitive drum 41 with laser light based on the input image information. At this time, the photosensitive drum 41 is charged in advance by a charging roller (not shown), and an electrostatic latent image is formed on the photosensitive drum 41 when irradiated with laser light. Thereafter, the electrostatic latent image is developed by a developing roller (not shown) included in the process cartridge 42, and a toner image is formed on the photosensitive drum 41.

  In parallel with the image forming operation described above, the sheets S stacked on the cassette 30 are separated and fed one by one by the feeding roller 111 and a separation pad (not shown). The fed sheet S is conveyed to the registration roller pair 102. The registration roller pair 102 forms a loop on the sheet to correct skewing, and conveys the sheet S toward the transfer nip N formed by the photosensitive drum 41 and the transfer roller 103 at a predetermined conveyance timing. The toner image formed on the photosensitive drum 41 is transferred to the sheet S by applying a transfer bias from the transfer roller 103 in the transfer nip N.

  Further, the sheet S that has passed through the transfer nip N is heated and pressed by the fixing roller pair 104 to fix the toner image, and is discharged onto the discharge tray 108 outside the apparatus by the discharge triple roller 50 (discharge means). Discharged. The discharge triple roller 50 includes a discharge roller 105, a discharge roller 106, and a double-sided roller 107. When the sheet S is discharged to the discharge tray 108, the sheet S is a guide member. 51 is guided to the discharge roller 105 and the discharge roller 106. Further, the sheet S is guided from the cassette 30 to the discharge triple roller 50 through the sheet conveyance path 32.

  When images are formed on both sides of the sheet S, the sheet S on which the image is formed on the first side is conveyed to the discharge roller 105 and the double-sided roller 107 by the rotatable guide member 51. The sheet S is switched back by the discharge roller 105 and the double-sided roller 107 and conveyed to the double-sided conveyance path 21. The sheet S conveyed to the duplex conveyance path 21 is conveyed again to the registration roller pair 102 by the duplex conveyance unit 20, an image is formed on the second surface in the transfer nip N, and is discharged to the discharge tray 108.

  A core frame 101 (frame member), which will be described later, is provided above the duplex conveying unit 20. The core frame 101 includes a first guide 71 and a second guide 72 that constitute part of the double-sided conveyance path 21, and a third guide 73 (conveyance guide) that constitutes a part of the sheet conveyance path 32. It is. The core frame 101 connects both side plates (not shown) of the printer 100 provided in the front and back direction of the paper shown in FIG. 1 and positions and holds the process cartridge 42. Further, the core frame 101 supports (holds) the transfer roller 103 in a rotatable manner.

  As shown in FIG. 2, the double-sided conveyance unit 20 includes a double-sided conveyance guide 201 that forms part of the double-sided conveyance path 21, a regulating member 202 attached to the double-sided conveyance guide 201, a skew correction roller pair 60, A conveyance roller pair 61 and a skew feeding roller guide 206 are provided. The double-sided conveyance guide 201 is configured to be rotatable about a rotation fulcrum 201a with respect to a frame or core frame 101 (not shown). The skew feeding correction roller pair 60 (skew feeding correction means) is driven by a drive source (not shown) and is driven to rotate by a skew feeding roller 203 (drive roller) rotatably supported by the core frame 101 and the skew feeding roller 203. And the inclined feeding roller 204 (driven roller). The oblique feeding roller 204 is provided to be inclined with respect to the oblique feeding roller 203, and the skew feeding correction roller pair 60 conveys the sheet obliquely toward the regulating member 22 (regulating means). The duplex conveying roller pair 61 includes a refeed roller 207 that is driven by the drive source and is rotatably supported by the core frame 101, and a refeed roller 208 that is rotated by the refeed roller 207. ing.

  The sheet S that has been switched back and conveyed by the discharge roller 105 and the double-sided roller 107 is abutted against the reference surface 202a of the regulating member 202 at the end in the width direction of the sheet by the obliquely feeding roller 203 and the obliquely feeding roller 204. While being conveyed in the direction of arrow A. The sheet S is conveyed along the reference surface 202a (regulatory surface) to correct skewing, and is conveyed to the sheet conveyance path 32 by the refeed roller 207 and the refeed roller 208.

  As shown in FIG. 3, the restricting member 202 is made of sheet metal, and a reference surface 202a is formed on the inner side of the bent shape in a substantially U shape. The restricting member 202 has a guide portion 202b that guides the sheet to the reference surface 202a on the upstream side in the sheet conveyance direction. The restricting member 202 includes a fitting portion 202c (positioning portion) extending upward and an insertion portion 202d (fixing portion).

  As shown in FIG. 4A, the core frame 101 includes a fitted portion 75 that is fitted with the side surface of the fitting portion 202c and is fitted, and an attachment portion 101a into which the insertion portion 202d is inserted. . As shown in FIG. 4B, the mounting portion 101a has three projecting portions 76, 77, 78 that project alternately in the width direction of the sheet, and an insertion portion is inserted into these projecting portions 76, 77, 78. 202d is press-fitted. That is, the restricting member 202 is fixed with high accuracy by positioning the fitting portion 202c against the fitted portion 75 and pressing the insertion portion 202d into the mounting portion 101a.

  As shown in FIG. 5, the oblique feed roller guide 206 (holding means) is formed in a substantially rectangular shape, and supports the oblique feed roller 204 in a rotatable manner. The skew feeding roller guide 206 holds a skew feeding roller spring 205 (biasing means) that biases the skew feeding roller 204 to the skew feeding roller 203.

  The oblique feed roller guide 206 is configured to be attachable to the core frame 101. When the oblique feed roller guide 206 is attached to the core frame 101, the oblique feed roller guide 206 is substantially flush with the double-sided conveyance guide 201 and directly below the regulating member 202. It is arranged in the direction. In other words, the regulating member 202 is prevented from being detached from the core frame 101 by attaching the skew feeding roller guide 206 to the core frame 101.

  As described above, the double-sided conveyance guide 201 is provided so as to be openable and closable around the rotation fulcrum 201a, and in FIG. 6A, the double-sided conveyance guide 201 is closed and the sheet is fed into the double-sided conveyance path 21. It is a state that can be. When a sheet is jammed in the duplex conveyance path 21, the user opens the duplex conveyance guide 201 downward as shown in FIG. The regulating member 202 and the oblique feed roller guide 206 are configured not to interfere with the double-sided conveyance guide 201 when the double-sided conveyance guide 201 is opened downward.

  That is, even if the double-sided conveyance guide 201 is opened downward for jamming, the regulating member 202 and the oblique feed roller guide 206 are attached to the core frame 101. For this reason, even if the user performs jam processing, the positioning accuracy of the skew feeding roller 203, the skew feeding roller 204, and the regulating member 202 is not affected, so that the sheet can be skewed accurately.

  The core frame 101 has a third guide 73 that is a part of the sheet conveyance path 32 that guides the sheet to the transfer nip N, and the regulating member 202 and the oblique feeding roller guide 206 are positioned with respect to the core frame 101. Has been. For this reason, the tolerance is hardly affected between the skew correction roller pair 60 and the reference surface 202a of the regulating member 202 and the transfer nip N, and an image can be transferred to the sheet with good positional accuracy. Furthermore, since the core frame 101 holds the process cartridge 42 and the transfer roller 103, an image can be transferred to the sheet with better positional accuracy.

  In this embodiment, the core frame 101 holds the process cartridge 42 and the transfer roller 103, but the present invention is not limited to this. That is, the core frame 101 may not hold the process cartridge 42 and the transfer roller 103, and may be configured to hold one of the process cartridge 42 and the transfer roller 103.

  In the present embodiment, the transfer bias is applied to the transfer roller 103 to transfer the toner image onto the sheet. However, the transfer roller 103 may be formed of a belt instead of the roller. Further, the present invention may be applied not only to a monochrome laser beam printer but also to a full color laser beam printer and an ink jet printer.

  In the present embodiment, the skew correction roller pair 60 is configured to abut the end portion of the sheet against the reference surface 202a of the regulating member 202. However, the present invention is not limited to this. For example, the double-sided conveyance guide 201 may be inclined so that the sheet slides down toward the reference surface 20a to correct the skew of the sheet.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the second embodiment, the restricting member of the first embodiment is constituted by parallel pins, and the first embodiment is the same as the first embodiment. A similar configuration will be described by omitting illustration or attaching the same reference numerals to the drawings. As shown in FIG. 7, the core frame 301 (frame member) has a regulation guide portion 303 that projects downward from the first guide 71.

  A plurality of (two in this embodiment) parallel pins 302, 302 (regulating means) made of metal are insert-molded and fixed to the regulating guide portion 303. In addition, the regulation guide portion 303 is formed continuously with a guidance surface 303a that guides the sheet to the parallel pins 302 and 302, and a regulation surface 303b that extends in parallel with the sheet conveyance direction (arrow A direction in FIG. 2). And have.

  A part of the outer peripheral surface of the parallel pins 302, 302 protrudes from the regulation surface 303 b toward the inside of the double-sided conveyance path 21. For this reason, the sheet conveyed (skewed) by the skew feeding correction roller pair 60 is mainly abutted against the parallel pins 302 and 302 to correct the skew feeding. Since the parallel pins 302 and 302 are made of metal, they have high durability and can reduce the frequency of parts replacement.

  The parallel pins 302 and 302 are fixedly positioned by insert molding to the regulation guide portion 303 of the core frame 301 and positioned. For this reason, a tolerance is hardly affected between the parallel pins 302 and 302 and the transfer nip N, and an image can be transferred with good positional accuracy to the sheet.

  In this embodiment, two parallel pins 302 are provided. However, three or more parallel pins 302 may be provided.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. In the third embodiment, the restricting member of the first embodiment is composed of parallel pins, and the parallel pins are connected to the oblique feed roller guide 206. It is fixed. For this reason, about the structure similar to 1st or 2nd embodiment, illustration is abbreviate | omitted or attaches | subjects the same code | symbol to a figure and demonstrates.

  As shown in FIG. 8, the skew feeding roller guide 406 (holding means) has a guide surface 406b for guiding the conveyed sheet and a regulation guide portion 403 extending upward from the guide surface 406b. A plurality (two in this embodiment) of parallel pins 402 and 402 (regulating means) made of metal are insert-molded and fixed to the regulating guide portion 403. In addition, the regulation guide portion 403 is formed continuously with a guidance surface 403a for guiding the sheet to the parallel pins 402 and 402, and a regulation surface 403b extending in parallel with the sheet conveyance direction (arrow A direction in FIG. 2). And have.

  The upper portion 402a of the parallel pin 402 is provided so as to protrude upward from the regulation guide portion 403, and the oblique feed roller guide 406 is formed by inserting the upper portion 402a of the parallel pin 402 into a positioning hole (not shown) of the core frame 101. Positioned.

  A part of the outer peripheral surface of the parallel pins 402 and 402 protrudes from the regulation surface 403b toward the inside of the double-sided conveyance path 21. For this reason, the sheet conveyed (skewed) by the skew feeding correction roller pair 60 is mainly abutted against the parallel pins 402 and 402 to correct the skew feeding.

  Since the present embodiment is configured as described above, the parallel feed pins 402 and 402 as the restricting means can be easily positioned with respect to the core frame by attaching the obliquely feeding roller guide 406 to the core frame 101. it can.

  21: Duplex conveying path, 30: Stacking means (cassette), 32: Sheet conveying path, 40: Image forming means (image forming unit), 41: Image carrier (photosensitive drum), 42: Image carrier unit (process) Cartridge), 50: discharge means (discharge triple roller), 60: pair of skew correction rollers (skew correction means), 73: transport guide (third guide), 100: image forming apparatus (printer), 101: frame Member (core frame), 103: transfer member (transfer roller), 202: restriction means (regulation member), 202a: restriction surface (reference surface), 202c: positioning portion (fitting portion), 202d: fixing portion (insertion portion) ), 203: driving roller (slope feeding roller), 204: driven roller (slope feeding roller), 205: biasing means (slope feeding roller spring), 206: holding means (slope feeding roller guide), 302, 402 Regulating means (parallel pin), S: seat

Claims (9)

A stacking means on which sheets are stacked;
Image forming means for forming an image on the sheet fed from the stacking means;
Discharging means for discharging the sheet on which the image is formed by the image forming means to the outside of the machine;
A sheet conveyance path for guiding sheets from the stacking means to the discharge means;
A double-sided conveyance path for conveying the sheet that has passed through the image forming unit to the image forming unit again;
A regulating means that is provided in the double-sided conveyance path and regulates an end portion in the width direction of the sheet;
A skew correction means for correcting the skew of the sheet while conveying the end of the sheet against the restriction means;
A frame member having a conveyance guide that constitutes a part of the sheet conveyance path,
The restricting means is attached to the frame member.
An image forming apparatus. The image forming unit includes an image carrier unit having an image carrier that carries a toner image, and a transfer member that transfers the toner image carried on the image carrier to a sheet,
The frame member holds at least one of the image carrier unit and the transfer member;
The image forming apparatus according to claim 1. The restricting means is made of sheet metal.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The frame member includes a regulation surface that regulates the end portion of the seat, a positioning portion that is positioned by being abutted against the frame member, and a fixing portion that is fixed to the frame member.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The fixing portion is press-fitted into the frame member;
The image forming apparatus according to claim 4. The restricting means comprises a plurality of metal parallel pins.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The plurality of parallel pins are fixed to the frame member by insert molding,
The image forming apparatus according to claim 6. The skew feeding correcting means includes a driving roller and a driven roller that is provided to be inclined with respect to the driving roller and that is driven to rotate by the driving roller.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The skew feeding correcting means includes a driving roller and a driven roller that is provided to be inclined with respect to the driving roller and is driven to rotate by the driving roller,
Urging means for urging the driven roller to the driving roller;
Holding means for holding the driven roller and the biasing means,
The plurality of parallel pins are fixed to the holding means by insert molding and attached to the frame member.
The image forming apparatus according to claim 6.

Images