JP2010006529A - Sheet carrying device, and image forming device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet carrying device capable of permitting the inclination of a pick-up roller and transmitting drive. <P>SOLUTION: The pick-up roller 1 is rotatably held by slide bearings 2, 3, and the slide bearings 2, 3 are pushed onto springs 4a, 4b to press the pick-up roller 1 on a paper bundle P. A pulley 6 is provided on a shaft 5 of the pick-up roller 1, and driving force is transmitted by a belt 8 and a feed shaft 9. When the paper bundle P or a bottom board 16a of a paper feeding tray 16 inclines in regard to the pick-up roller 1, the paper bundle P contacts with one side end portion of the pick-up roller 1, so that pick-up paper feeding laterally inclining is carried out. However, the shaft 5 of the pick-up roller 1 follows the inclination when a surface of the paper bundle P inclines, so that skewing due to unsatisfactory abutting on the paper bundle P of the pick-up roller 1 can be prevented. By coupling by the belt 8, the inclination of the pick-up roller 1 due to twisting of the belt 8 can be permitted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus used for a copying machine such as a PPC, a laser printer, a facsimile apparatus, a scanner apparatus, and the like, and an image forming apparatus provided with the sheet conveying apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a plurality of sheets are stacked on a sheet feeding unit such as a sheet feeding cassette provided at the lower part of the apparatus main body, and the sheets loaded on the sheet feeding unit are composed of rubber rollers or the like. Paper is fed one by one from the uppermost sheet in order by the separating and feeding means, conveyed to a predetermined image forming unit by a pair of conveying rollers and a pair of registration rollers, and image formation is performed. The thing of the structure discharged | emitted to the discharge part provided in is known.

  In the image forming apparatus having such a configuration, a skew in which the sheet is inclined with respect to the conveyance direction may occur during sheet feeding or in the middle of conveyance. In such a case, an image formed on the sheet is inclined. Therefore, as a method for preventing such a problem, a paper transport mechanism has been invented that can correct paper skew by a pair of registration rollers arranged upstream of the image forming unit.

  However, in the paper transport mechanism described in Patent Document 1, there is a limit to the skew that can be corrected by the registration roller pair. Therefore, in Patent Document 2, in the conveyance roller pair composed of a driving roller and a driven roller that is driven to rotate, the axis of the driven roller can be inclined with respect to the axis of the driving roller. There has been proposed a paper transport mechanism that is configured and capable of transporting a paper and correcting the skew when the paper transported on the transport path is skewed.

JP-A-8-91635 JP 2005-82310 A JP 2007-217125 A

  However, the paper transport mechanism described in Patent Document 2 is intended to correct skew that occurs during paper transport, and the pair of transport rollers capable of correcting skew prints an image on one side during duplex printing. Since the sheet is disposed only in the re-conveying path for conveying the sheet to the image forming unit again, the skew generated when the sheet is fed is corrected only by the pair of registration rollers as in the conventional sheet conveying mechanism. It is difficult to correct when there is a large skew during feeding.

  In view of the above circumstances, an object of the present invention is to provide an image forming apparatus capable of preventing a skew from occurring when a sheet is fed from a sheet feeding unit provided in the apparatus main body.

  A sheet conveying apparatus according to a first aspect of the present invention includes a sheet storage device on which sheets are stacked, and a pickup roller that feeds the sheets stacked on the sheet storage apparatus to the sheet conveying apparatus. In the image forming apparatus, the pickup roller is connected to a drive from a feed shaft by a belt and can be displaced in an inclination direction, and the pickup roller follows the inclination of the sheet.

  According to a second aspect of the present invention, in the sheet conveying apparatus according to the first aspect, pressure is applied to the bearing holding the shaft through which the pickup roller is passed by an elastic member to press the pickup roller against the paper, and the pickup roller The shaft is movable in the pressing direction independently on the left and right.

  According to a third aspect of the present invention, in the first aspect, the bearing of the pickup roller has a rotation center in the roller axial direction and is movable in the rotation direction.

  According to a fourth aspect of the present invention, in the first aspect, the pickup roller has a plurality of rollers in the axial direction, and the belt for connecting the drive is disposed at the center in the axial direction.

  An image forming apparatus according to a fifth aspect uses the sheet conveying apparatus according to the first to fourth aspects.

  According to a sixth aspect of the present invention, the image forming apparatus using the sheet conveying device according to any one of the first to fourth aspects is a copying machine, a printer, a facsimile machine, or a complex machine thereof.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, the sheet conveying apparatus according to any one of the first to fourth aspects is used as an automatic document feeder.

  According to the present invention, the bearing that supports the shaft of the pickup roller has a configuration that has a rotation center in the axial direction of the pickup roller and is movable in the rotation direction. While it is difficult to have a degree of freedom, it is possible to transmit the drive while allowing the inclination of the pickup roller by twisting the belt.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  First, FIG. 1 is a schematic front view showing an overall configuration of an example of an image forming apparatus to be mounted with a sheet conveying apparatus according to the present invention, specifically, an example of a copying machine. As shown in the figure, this image forming apparatus is a monochrome copying machine that reads an image from a document surface of a document and forms a copy image on various sheets of paper. It has a paper feeding device that feeds paper S, which is a recording medium such as a recording sheet and an OHP film, one by one to the main body. The paper feed unit is provided with a paper stacking plate (hereinafter referred to as a bottom plate) for stacking paper bundles and a paper stacking plate raising mechanism for urging the paper stack upward, and the stacked paper bundles are pressed against the pickup roller. The paper feed separation unit includes a pickup roller that feeds paper from a bundle of papers loaded in a paper feed tray (hereinafter referred to as a tray), a feed roller that is driven by the same drive source as the pickup roller and feeds the fed paper, and a pickup roller The belt comprises a belt connecting the shaft and the feed shaft, and a reverse roller pressed against the feed roller in order to prevent conveyance of the second and subsequent sheets when a plurality of sheets are fed out.

  Specifically, in FIG. 1, 11 is an image forming unit, 12 is a scanner unit, 13 is a transfer sheet S (in this specification, the transfer sheet is not only paper but also OHP sheet or the like in this type of apparatus) The recording medium includes all the objects to be transferred.) 14 is a pressure plate (or document feeder), and 15 is a contact glass. The paper feed unit 13 includes a pair of paper feed trays 16 and 16 and a manual feed tray 17. In the figure, reference numeral 18 denotes a paper discharge unit. In the figure, reference numeral 20 denotes a photosensitive unit provided with a photosensitive drum as a toner image carrier, around which a developing device 21, an optical unit 22, a transfer conveyance belt 23, a resist roller pair 24, a thermal fixing device 25, a double-sided image. A reversing conveyance unit 26 and the like for forming are arranged. Since the configuration and operation of these copying machines are well known, description thereof will be omitted. Needless to say, the present invention is not limited to the illustrated type of image forming apparatus, and can be applied to various types.

  All of the embodiments described below have this configuration, and the feature of each embodiment is the configuration of the pickup. Therefore, only different points will be described below for each claim.

FIG. 2 is a diagram showing a first embodiment of the present invention, and is a schematic diagram showing a sheet feeding / separating unit in a form installed in the image forming apparatus of FIG.
The pickup roller 1 is held by the sliding bearings 2 and 3 from the left and right and is rotatable. The pickup roller 1 is pressed against the sheet bundle P by the spring bearings 2 and 3 being pressed by the springs 4a and 4b. ing. Pulleys 6 and 6 are installed on the shaft 5 of the pickup roller 1 and are driven by a belt 8. In the drawing, 9 is a feed shaft for transmitting the driving force of the pickup roller 1.

  When the bottom plate 16a of the paper feed tray 16 is pressed against the pickup roller 1 by a lift mechanism (not shown), the bottom plate 16a is not in parallel to the pickup roller 1, but it is a piece-by-piece. The pickup roller 1 is inclined when the contacted side is pushed, and the entire area of the pickup roller 1 can abut on the upper surface of the sheet bundle P by following the sheet bundle P until the other contacts.

  That is, according to the present invention, the pickup roller 1 is connected to the drive from the feed shaft 9 by the belt 8 and can be displaced in the inclination direction. The pickup roller 1 follows the inclination of the sheet S or the sheet bundle P to be conveyed. Have

  When the sheet bundle P or the bottom plate 16a of the sheet feeding tray 16 is inclined with respect to the pickup roller 1 as a factor causing the above-described inclination, that is, skew, in the sheet feeding unit such as the sheet feeding tray 16 (FIG. 5). (See (A)). Since the sheet bundle P is in contact with one end of the pickup roller 1 (see FIG. 5B), it is conceivable that pick-up feeding that is biased left and right is performed. On the other hand, by making it movable in the tilt direction as in this embodiment, even when the shaft 5 of the pickup roller 1 and the surface of the sheet S or the sheet bundle P are inclined, the sheet bundle P or the like is imitated. (See FIG. 5C), and skew due to inadequate contact of the pickup roller 1 with the sheet bundle P can be prevented. In the configuration of the present invention, the driving force is not a gear connection but a belt connection, and in the case of a normal gear connection, it is difficult to have a degree of freedom in the inclination direction due to the twist of the belt. The drive can be transmitted while allowing the inclination of the pickup roller 1.

  As described above, Patent Document 3 similarly proposes a method in which the inclination of the pickup roller is changed by an adjustment mechanism. However, in the present invention, a separate adjustment mechanism is not required by providing the pickup itself with a degree of freedom. Yes, it can handle various loading conditions. Further, the bearing that supports the shaft 5 of the pickup roller 1 is configured so that the pickup roller is pressed against the sheet by applying pressure by an elastic member, and the pickup roller shaft is movable independently in the left and right directions.

  Having left and right degrees of freedom means that the pickup roller 1 has bearings on the left and right sides, and springs 4a and 4b are arranged on the bearings 2 and 3, respectively, so that the sheet bundle P is pressed independently. When the pickup roller 1 is in contact with the pickup roller 1 obliquely, even if one side of the pickup roller 1 hits, the pickup roller 1 can incline following the inclination of the sheet bundle P, and the pickup roller 1 is uniform with respect to the sheet bundle P. It will be in contact with.

  FIG. 3 is a diagram showing a second embodiment of the present invention, and is a schematic diagram showing a sheet feeding / separating unit installed in the image forming apparatus of FIG.

  As in the previous embodiment, the pickup roller 1 is held by sliding bearings 2 and 3 from the left and right, and the sliding bearings 2 and 3 are fixed to a movable bracket 30 having a fulcrum near the image forming apparatus main body as a rotating shaft 10. ing. When the bottom plate 16a is pressed against the pickup roller 1 by a lifting mechanism (not shown), if the bottom plate 16a is not parallel to the pickup roller 1, the bottom plate 16a is still one-sided. Is pushed, the pickup roller 1 rotates around the rotation shaft 10 and becomes inclined, and follows the upper surface of the sheet bundle P until the other contacts, so that the entire area of the pickup roller 1 contacts the upper surface of the sheet bundle P. be able to. Note that the projecting pieces 31 and 31 of the bracket 30 abut against the bearings 2 and 3 of the pickup roller 1, respectively, and perform the same function as the springs 4a and 4b.

  FIG. 4 is a diagram showing a third embodiment of the present invention, and is a schematic diagram showing a sheet feeding / separating unit in a form installed in the image forming apparatus of FIG.

  The basic configuration of the present embodiment is not different from that of the first embodiment, but the pickup roller 1 and the feed roller 7 are divided into two at the center in the axial direction, and the driving belt 8 is centered in the axial direction of the pickup roller 1. This arrangement makes it difficult for the pickup roller 1 to be affected by the twist of the drive transmission belt 8 when the pickup roller 1 is inclined. Similarly to the previous embodiment, the pickup roller 1 is held by the sliding bearings 2 and 3 from the left and right so as to be rotatable, and the pickup roller 1 is pushed by the springs 4a and 4b. Is pressed against the sheet bundle P. A pulley 6 is installed on the shaft 5 of the pickup roller 1 and is driven by a belt 8. When the bottom plate 16a is pressed against the pickup roller 1 by a lifting mechanism (not shown), the bottom plate 16a is hit when it is not parallel to the pickup roller 1. Then, the pickup roller 1 rotates about the rotation axis and becomes inclined, and the entire pickup roller can contact the sheet by following the sheet until the other contacts. As a result, as described above, when the pickup roller 1 is inclined, it is less susceptible to the twist of the belt 8.

  In the above-described embodiments, the image forming apparatus has been described as a copying machine. However, it can be used for a printer, a facsimile machine, a sheet conveying apparatus, and an automatic document feeder. By using the above-described sheet conveying device in various image forming apparatuses, it is possible to realize an image forming apparatus having a sheet feeding unit with a high skew prevention effect.

  For example, if the image forming apparatus is a copying machine, a copying machine having a paper feeding unit having a high skew prevention effect can be realized. If the image forming apparatus is a printer, a printer having a paper feeding unit having a high skew prevention effect can be realized. If it is a facsimile machine, it is possible to realize an apparatus configuration having a paper feeding unit with a high skew prevention effect. If the above-described sheet conveying device is used in the automatic document feeder (ADF), an automatic document feeder having a paper feeding unit having a high skew prevention effect can be realized.

1 is a schematic front view showing an overall configuration of an example of an image forming apparatus to be mounted on a sheet conveying apparatus according to the present invention. The figure which shows 1st Example of this invention The figure which shows Example 2 of this invention The figure which shows Example 3 of this invention Conceptual diagram (A) in a state where the sheet bundle and the bottom plate of the paper feed tray are inclined with respect to the pickup roller, conceptual diagram (B) in a state where the sheet is in contact with one end of the pickup roller, shaft of the pickup roller and the sheet Alternatively, a conceptual diagram (C) of a state that follows the inclination of the sheet bundle even when the surface of the sheet bundle is inclined.

Explanation of symbols

1: Pickup roller 2, 3: Sliding bearing 4a, 4b: Spring 5: Pickup roller shaft 6: Pulley 8: Belt 9: Feed shaft 10: Rotating shaft 11: Image forming section 12: Scanner section 13: Paper feed section 14 : Pressure plate (or document feeder)
15: Contact glass 16: Paper feed tray 16a: Bottom plate of paper feed tray 17: Manual feed tray 18: Paper discharge unit 20: Photosensitive unit 21: Developing device 22: Optical unit 23: Transfer conveyance belt 24: Registration roller pair 25: Thermal fixing device 26: Reverse conveyance unit 30: Bracket S: Transfer paper P: Paper bundle

Claims (7)

A paper storage device on which paper is loaded; and
A pickup roller that feeds the paper stacked in the paper storage device to a sheet conveying device;
In an image forming apparatus comprising:
The pickup roller is connected to a drive from a feed shaft by a belt,
And can be displaced in the tilt direction,
A sheet conveying apparatus, wherein a pickup roller follows the inclination of a sheet. In the sheet conveying apparatus according to claim 1,
Apply pressure to the bearing that holds the shaft through which the pickup roller passes by an elastic member to press the pickup roller against the paper,
The sheet conveying apparatus, wherein the shaft of the pickup roller is movable in the pressing direction independently on the left and right. In the sheet conveying apparatus according to claim 1,
A sheet conveying apparatus, wherein the pickup roller bearing has a rotation center on an axis of the pickup roller, and the bearing is movable in the pressing direction. The sheet conveying apparatus according to claim 1, wherein the pickup roller has a plurality of rollers on its shaft,
A sheet conveying apparatus, wherein a belt for connecting the drive is disposed at a position between the plurality of rollers and in the center in the axial direction of the shaft. An image forming apparatus using the sheet conveying device according to claim 1. An image forming apparatus using the sheet conveying apparatus according to claim 1, wherein the image forming apparatus is a copying machine, a printer, a facsimile machine, or a complex machine thereof. 7. The image forming apparatus according to claim 5, wherein the sheet conveying device according to claim 1 is used as an automatic document feeder.