JP2007314256A - Sheet discharging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet discharging device for discharging a sheet by providing corrugation to the sheet and enhancing a straight advancing property which is capable of preventing the sheet from being stained or damaged. <P>SOLUTION: The sheet discharging device has a drive roller and a driven roller, and discharges a sheet by holding and conveying the sheet by the drive roller and the driven roller. The sheet discharging device discharges the sheet by providing corrugation to the sheet. A large diameter roller which has the radius larger than the radius of the drive roller or the radius of the driven roller and can be rotated independently from the drive roller or the driven roller following the sheet to be conveyed is provided on a shaft of the drive roller or a shaft of the driven roller. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet discharging apparatus for discharging sheets such as paper and film in a copying machine, a facsimile, a printer, an image reading apparatus, and the like.

  In the sheet discharge device, by curving the discharged sheet in the conveyance width direction, the sheet is strained, the straightness is improved, the discharge is smoothly performed, and the alignment of the discharged sheet is facilitated. (For example, Patent Documents 1 and 2).

  In Patent Document 1, problems such as streaking of the sheet are solved by devising the shapes of the large-diameter member and the small-diameter member that give corrugation to the sheet.

In Patent Document 2, a thick sheet is prevented from being damaged by providing a corrugation roller so that it can be retracted independently in a direction away from the conveying roller.
JP 2005-67786 A JP 2005-96889 A

  As described above, when a sheet is conveyed using a roller having a large diameter portion and a small diameter portion, the large diameter portion and the small diameter portion are driven by the same drive source and rotate at the same rotation speed. The peripheral speed differs from the peripheral speed of the small-diameter portion, and as a result of rubbing the sheet due to the difference in peripheral speed, there is a problem that the sheet is made dirty and scratched.

  Such a phenomenon will be described with reference to FIG.

  The driving roller 5 has a small diameter portion 5A and a large diameter portion 5B, and the driven roller 6 is in pressure contact with the small diameter portion 5A. The sheet S is sandwiched between the driving roller 5 and the driven roller 6 and conveyed by the rotation of the driving roller 5.

  In the conveyance, the sheet S is bent by a step between the small diameter portion 5A and the large diameter portion 5B, and corrugation is applied to increase straightness, and the sheet S is discharged in a constant direction.

  However, when the discharge roller 5 rotates at the rotational speed V to convey and discharge the sheet S, if the radius of the small diameter portion 5A is RI and the radius of the large diameter portion 5B is R2, the small diameter portion 5A and the large diameter portion A circumferential speed difference V (R2−R1) is generated between 5B and 5B.

  Since the conveyance of the sheet S is performed by the conveyance force generated in the small diameter portion 5A to which the driven roller 6 is pressed, the large diameter portion 5B rotates by rubbing the sheet S by the peripheral speed difference V (R2-R1). Due to the rubbing of the large diameter portion 5B, a part of the rubber constituting the driving roller 5 may adhere to the sheet S to cause the sheet to become dirty, or the sheet S may be scraped and damaged.

  In Patent Document 1, although the shape is devised, the large-diameter portion and the small-diameter portion rotate integrally, so that it is not sufficient to solve the problem that the sheet can become dirty or scratched.

  The same applies to Patent Document 2.

  An object of the present invention is to solve the above-described problems that occur when corrugation is applied to a sheet and discharged.

The object is achieved by the following invention.
1.
A sheet discharging apparatus that has a driving roller and a driven roller, and discharges the sheet by sandwiching and transporting the sheet between the driving roller and the driven roller, and discharges the sheet by applying corrugation In
The shaft of the driving roller or the shaft of the driven roller has a radius larger than the radius of the driving roller or the driven roller, and follows the conveyed sheet and independently of the driving roller or the driven roller. A sheet discharging apparatus comprising a large-diameter roller capable of rotating.
2.
2. The sheet according to 1, wherein the sheet has a drive shaft that supports the drive roller, the drive roller is fixed to the drive shaft, and the large-diameter roller is rotatably attached to the drive shaft. Discharging device.
3.
The large diameter roller is disposed close to the driving roller or the driven roller, and a plurality of corrugation units including the driving roller or the driven roller and the large diameter roller are provided. The sheet discharging apparatus according to 2 above.
4).
3. The sheet discharging apparatus according to 1 or 2, wherein a corrugation unit in which the large-diameter roller is disposed between the two driving rollers or the driven roller is provided.

  In the present invention, corrugation is imparted to the sheet by the driving roller or driven roller and the large diameter roller using a large diameter roller that can rotate independently of the driving roller or driven roller. While discharging smoothly, there is no difference in the peripheral speed of the large-diameter roller, and image stains and sheet scratches caused by this peripheral speed difference can be prevented.

  The present invention will be described below with reference to illustrated embodiments, but the present invention is not limited to these embodiments.

  2 is a sectional view of the sheet discharging apparatus according to the embodiment of the present invention, FIG. 3 is a sectional view of the sheet discharging apparatus shown in FIG. 2 as viewed from the sheet discharge side, and FIG. 4 is an enlarged view of the corrugation unit. Reference numerals 1 and 2 are conveying rollers, 3 and 4 are guide plates that form a conveying path in the paper discharge unit, 5 is a driving roller, 6 is a driven roller that is driven to rotate in contact with the sheet S being conveyed, and 7 is a paper discharge tray. It is.

  The sheet S is conveyed by the conveying rollers 1 and 2, guided by the guide plates 3 and 4, and enters the paper discharge unit. In the paper discharge unit, the sheet S is nipped and conveyed by the driving roller 5 and the driven roller 6 to be the paper discharge tray 7. To be discharged.

  The drive roller 5 includes four rubber drive rollers 5A1 to 5A4 fixed to the drive shaft 5C. The driving rollers 5A1 and 5A3 and the driving rollers 5A2 and 5A4 are arranged symmetrically about the center line CL of the conveyance path.

  5D1 to 5D4 are free rollers as large-diameter rollers that are rotatably supported with respect to the drive shaft 5C, and are made of rubber or resin. As shown in FIG. 4, the driving roller 5A1 has a small radius R1, and the free roller 5D1 has a radius R2 larger than R1 to constitute a large diameter roller. The driven rollers 61 to 64 are brought into pressure contact with the driving rollers 5A1 to 5A4 to convey the sheet S. The drive roller 5A1 is fixed to the shaft 5C, while the free roller 5D1 is rotatably attached to the shaft 5C, and the axial direction of the drive shaft 5C is regulated by a washer 5E fitted in the groove 5F of the drive shaft 5C. Is held at a certain position. Similarly, the driving rollers 5A2 to 5A4 and the free rollers 5D2 to 5D4 are attached to the driving shaft 5C. As shown in FIG. 3, the free roller 5D1 is disposed at a close position inside the drive roller 5A1 (from the center line CL), and the free roller 5D2 is disposed at a close position inside the drive roller 5A2 (from the center line CL). The free roller 5D3 is disposed at a position close to the outside (from the end portion) of the drive roller 5A3, and the free roller 5D4 is disposed at a position close to the outside (from the end portion) of the drive roller 5A4. The driving roller 5A1, the free roller 5D1, the driven roller 61, the driving roller 5A2, the free roller 5D2, the driven roller 62, the driving roller 5A3, the free roller 5D3, the driven roller 63, and the driving roller 5A4, the free roller 5D4, and the driven roller 64, respectively. A corrugation unit that provides corrugation to the sheet S is configured.

  61-64 are resin driven rollers. The driven rollers 61 and 63 are supported by the shaft 8A and are pressed against the driving rollers 5A1 and 5A3 by the spring 9A, respectively. The driven rollers 62 and 64 are supported by the shaft 8B and are pressed by the spring 9B to the driving rollers 5A2 and 5A4, respectively. To do.

  The drive rollers 5A1 to 5A4 are rotated by the rotation of the drive shaft 5C, and the sheet S is conveyed and discharged to the sheet discharge tray 7. The drive rollers 5A1 to 5A4 and the free rollers 5D1 to 5D4 having different radii form the sheet S. Corrugation is formed, and the sheet S goes straight from the paper discharge unit and is discharged. At that time, the free rollers 5D1 to 5D4 follow the sheet S and rotate independently of the drive rollers 5A1 to 5A4. Therefore, the free rollers 5D1 to 5D4 do not rub the sheet S, and the sheet S does not become dirty or scratched.

  Each of the free rollers 5D1 to 5D4 is preferably disposed close to the drive rows 5A1 to 5A4, whereby the sheet S is strongly bent to form a good corrugation, and the sheet S is discharged more smoothly. .

  FIG. 5 shows another example of the sheet discharging apparatus according to the embodiment of the present invention.

  In this example, as in the example of FIGS. 2 and 3, four drive rollers 5A1 to 5A4 are provided, and the drive roller 5A1 and the drive roller disposed on one side centering on the center line CL of the transport path. A free roller 5D1 is disposed between 5A3 and a free roller 5D2 is disposed between the drive roller 5A2 and the drive roller 5A4 disposed on the other side.

  As shown in the figure, two corrugations are provided by the driving rollers 5A1, 5A3, the free rollers 5D1, and the driven rollers 61, 63, and the driving rollers 5A2, 5A4, the free rollers 5D2, and the driven rollers 62, 64. A unit is formed, and the sheet S is straightly discharged by these corrugation units.

  FIG. 6 is a diagram showing a corrugation unit in still another example of the embodiment of the present invention.

  In this example, the driven roller 6A is in pressure contact with the driven paper discharge roller 5A, and further, a free roller as a large-diameter roller having a radius larger than the radius of the driven paper discharge roller 6A to which the driven roller 6A is attached. 6B1 and 6B2 are attached. The free rollers 6B1 and 6B2 are rotatably attached independently of the driven roller 6A.

  Also in this example, the driven roller 6A and the free rollers 6B1 and 6B2 provide corrugation to the sheet S, and the driven roller 6A and the free rollers 6B1 and 6B2 rotate independently, so that the free rollers 6B1 and 6B2 The sheet S is driven and rotated independently of the driven sheet discharge rollers 6A1 to 6A4, and the sheet S is not rubbed.

  FIG. 7 shows an image forming apparatus according to an embodiment of the present invention in which the sheet discharge apparatus described above is incorporated.

  In FIG. 7, 10Y, 10M, 10C, and 10K are photosensitive members, 11Y, 11M, 11C, and 11K are charging devices, 12Y, 12M, 12C, and 12K are exposure devices, 13Y, 13M, 13C, and 13K are developing devices, and 14Y, 14M, 14C and 14K are cleaning devices for cleaning the surface of the photosensitive member, 15Y, 15M, 15C and 15K are primary transfer devices, and 20 is an intermediate transfer member formed of an endless belt.

The image forming unit Y includes a photoreceptor 10Y, a charging device 11Y, an exposure device 12Y, a developing device 13Y, a cleaning device 14Y, and a primary transfer device 15Y.
The image forming unit M includes a photoreceptor 10M, a charging device 11M, an exposure device 12M, a developing device 13M, a cleaning device 14M, and a primary transfer device 15M.
The image forming unit C includes a photoreceptor 10C, a charging device 11C, an exposure device 12C, a developing device 13C, a cleaning device 14C, and a primary transfer device 15C.
The image forming unit K includes a photoreceptor 10K, a charging device 11K, an exposure device 12K, a developing device 13K, a cleaning device 14K, and a primary transfer device 15K. The charging device 11Y and the exposure device 12Y, the charging device 11M and the exposure device 12M, The charging device 11C and the exposure device 12C, and the charging device 11K and the exposure device 12K constitute a latent image forming unit that forms an electrostatic latent image on the photoreceptors 10Y, 10M, 10C, and 10K, respectively.

  The image forming units Y, M, C, and K constitute an image forming unit that forms a toner image on the intermediate transfer member 20, and these units are Y, M, C, and K with respect to the traveling direction of the intermediate transfer member 20. The photoconductors 10Y, 10M, 10C, and 10K are in contact with the stretched surface of the intermediate transfer body 20, and rotate at the contact point in the same direction as the traveling direction of the intermediate transfer body 20 and at the same linear speed. To do.

  The intermediate transfer member 20 is stretched around a driving roller 21, an earth roller 22, a tension roller 23, and a driven roller 24, and the belt unit BU is constituted by these rollers, the intermediate transfer member 20, the primary transfer device 25, the cleaning device 29, and the like. To do.

  The intermediate transfer member 20 travels by rotation of the drive roller 21 by a drive motor (not shown).

  The primary transfer devices 15Y, 15M, 15C, and 15K are applied with a DC voltage having a polarity opposite to that of the toner, and transfer the toner images formed on the photoreceptors 10Y, 10M, 10C, and 10K onto the intermediate transfer body 20. . The primary transfer device 15 has a transfer roller composed of a semiconductive foam roller.

  The secondary transfer device 26 has a transfer roller 26 </ b> A as a transfer member that can contact and release the intermediate transfer body 20, and a transfer power source 26 </ b> B that applies a transfer voltage to the transfer roller 26 </ b> A, and is formed on the intermediate transfer body 20. The transferred toner image is retransferred to the recording material P. The transfer roller 26A is a semiconductive foam roller.

  Reference numeral 27 denotes a paper feeding unit that supplies the recording material P to a transfer position where transfer by the secondary transfer device 26 is performed, 28 denotes a fixing device that fixes an unfixed toner image on the recording material P, and 29 denotes a cleaning of the intermediate transfer body 20. It is a cleaning device.

  In the image forming units Y, M, C, and K, a single color toner image is formed, transferred to the intermediate transfer member 20 by the primary transfer devices 15Y, 15M, 15C, and 15K, and superimposed on the intermediate transfer member to form a color toner image. Is formed. The color toner image on the intermediate transfer member 20 is transferred to the recording material P by the secondary transfer device 26. The color toner image transferred to the recording material P is fixed by the fixing device 28.

  The recording material P on which the toner image is fixed is discharged by the sheet discharge device EX described above.

  The photoreceptors 10Y, 10M, 10C, and 10K after the transfer are cleaned by the cleaning devices 14Y, 14M, 14C, and 14K, respectively. Further, the intermediate transfer member 20 after the transfer is cleaned by a cleaning device 29.

It is a figure for demonstrating the phenomenon in which a sheet | seat is dirty and a damage | wound. It is sectional drawing of the sheet discharge apparatus which concerns on embodiment of this invention. 3 is a cross-sectional view of the sheet discharge apparatus shown in FIG. 2 as viewed from the sheet discharge side. It is an enlarged view of a corrugation unit. It is a figure which shows the other example of the sheet discharge apparatus which concerns on embodiment of this invention. It is a figure which shows the corrugation unit in the further another example of embodiment of this invention. 1 shows an image forming apparatus in which a sheet discharge apparatus according to an embodiment of the present invention is incorporated.

Explanation of symbols

5, 5A1-5A4 Drive roller 5D1-5D4, 6B1, 6B2 Free roller 6, 61-64, 6A Free roller

Claims (4)

A sheet discharging apparatus that has a driving roller and a driven roller, and discharges the sheet by sandwiching and transporting the sheet between the driving roller and the driven roller, and discharges the sheet by applying corrugation In
The shaft of the driving roller or the shaft of the driven roller has a radius larger than the radius of the driving roller or the driven roller, and follows the conveyed sheet and independently of the driving roller or the driven roller. A sheet discharging apparatus comprising a large-diameter roller capable of rotating. The drive shaft for supporting the drive roller, the drive roller is fixed to the drive shaft, and the large-diameter roller is rotatably attached to the drive shaft. Sheet discharge device. 2. The large-diameter roller is disposed in the vicinity of the driving roller or the driven roller, and a plurality of corrugation units including the driving roller or the driven roller and the large-diameter roller are provided. Or a sheet discharging apparatus according to claim 2. The sheet discharging apparatus according to claim 1, wherein a corrugation unit in which the large-diameter roller is disposed between the two driving rollers or the driven roller is provided.

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