JP2009120364A - Paper feeder and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder which is compactly formed, in which the surface of a separation roller is continuously cleaned, and which can feed paper sheets while surely separating the paper sheets one by one. <P>SOLUTION: This paper feeder 30 comprises a pickup roller 31, the feed roller 32, the separation roller 33, and a cleaning roller 34 brought into contact with the separation roller 33 to clean the surface thereof. The paper feeder further comprises a drive roller 37 mounted on the pivot shaft 33a of the separation roller 33 and a driven roller 38 mounted on the pivot shaft 34a of the cleaning roller 34 and brought into contact with the peripheral surface of the drive roller 37. The cleaning roller 34 obtains a rotating power from the pivot shaft 33a of the separation roller 33 by the frictional driving of a driven roller 38 by the drive roller 37. Since a plurality of gears do not need to be disposed between the pivot shaft 33a of the separation roller 33 and the pivot shaft 34a of the cleaning roller 34, a disposing space for these gears does not need to be secured is so disposed that a normal line L1 extending through the contact portion between the cleaning roller 34 and the separation roller 33 and the center of rotation of the separation roller 33 is generally perpendicular to the normal line L3 extending through the contact portion between the separation roller 33 and the feed roller 32 and the center of rotation of the separation roller 33. Since the contact of the cleaning roller 34 and the separation roller 33 does not almost affect the contact of the separation roller 33 and the feed roller 32, the cleaning roller 34 can always be brought into contact with the separation roller 33. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paper feeding device such as a cut paper, which can be applied to an image forming apparatus represented by a copying machine or a printer. The present invention also relates to an image forming apparatus equipped with this paper feeding device.

  The paper feeding device is indispensable for feeding paper such as cut paper in image forming apparatuses represented by copying machines and printers. In a paper feeding device in an image forming apparatus, a large number of sheets before printing are stocked in advance in a paper container such as a paper cassette or a paper tray, and one sheet from the top layer of the paper stacked in the paper container Many papers are supplied separately. Such a sheet feeding device is used for a cassette type sheet feeding unit, a manual sheet feeding unit, a document feeding unit, and the like of an image forming apparatus.

  There are a roller supply method and a suction supply method as a method of a paper feeding device for feeding paper to the outside of the paper storage unit, and the roller supply method is generally widely used. In the roller supply method, the pickup roller contacts the uppermost layer of the sheet bundle, delivers the sheet to the sheet feeding roller on the downstream side in the sheet feeding direction, and feeds the sheet to the outside of the sheet storage unit.

  Separating members such as a separating roller and a separating pad are used to separate the sheets fed by the sheet feeding roller one by one. These separation members come into contact with the paper feed roller from below, and when the problem of double feeding that the paper overlaps and is sent out, the feeding of the paper on the separating member side is stopped or the paper is stored in the paper. Return to the club side.

Here, when the separating member as described above is used, there is a concern that paper powder adheres to the surface of the separating member and the separation performance of the sheet deteriorates. Such adhesion of paper dust causes a problem that the life of the separating member is shortened in addition to a decrease in separating performance. In order to solve this problem, several methods for cleaning the surface of the separating member have been proposed, and examples of the paper feeding device can be seen in Patent Documents 1 and 2. The paper feeding device (sheet feeding device, paper feeding means) described in Patent Documents 1 and 2 cleans the surface of the separation roller by bringing a separation roller (separation roller, separation roller) into contact with a cleaning roller (cleaning roller). is doing.
JP 7-215510 A (page 4, FIG. 1) JP 2004-359449 A (page 9, FIG. 2)

  In the case of providing a plurality of adjacent rollers such as a separation roller and a cleaning roller that contacts and cleans the separation roller of the paper feeding device described in Patent Documents 1 and 2, each of the paper feeding devices is provided via a gear from a single motor. A driving method for supplying power to the roller is common. However, in this driving method, it is necessary to arrange a plurality of gears between the support shafts of each roller, and it is necessary to secure an arrangement space for the gear group. A recent image forming apparatus is required to be a compact model that saves installation space, and the arrangement of the gear group as described above is highly likely to hinder downsizing of the apparatus. In particular, since the separation roller and the cleaning roller of the sheet feeding device may be arranged in the sheet feeding cassette, it is necessary to store these rollers in the sheet feeding cassette using a space as small as possible.

  The present invention has been made in view of the above points, and with a compact structure, the surface of the separation roller can be continuously cleaned, and sheets can be reliably separated and supplied one by one. It is an object of the present invention to provide a possible paper feeding device. Another object of the present invention is to provide a high-performance image forming apparatus equipped with such a sheet feeding device.

  In order to solve the above-described problems, the present invention provides a pickup roller that feeds a sheet from a sheet storage unit, a sheet supply roller that receives the sheet from the pickup roller and carries it out of the sheet storage unit, and the sheet supply roller. A drive roller provided on a support shaft of the separation roller; a separation roller that contacts and separates the overlapping sheets; and a cleaning roller that contacts the separation roller and cleans the surface thereof; The cleaning roller is provided with a driven roller that is provided on the support shaft of the cleaning roller and contacts the peripheral surface of the drive roller. The cleaning roller obtains rotational power from the support shaft of the separation roller by friction driving of the driven roller by the drive roller.

  In the sheet feeding device having the above-described configuration, the diameter of the driving roller and the diameter of the driven roller are different from each other.

  In the present invention, the paper feeding device is mounted on the image forming apparatus.

  According to the configuration of the present invention, the pickup roller that feeds the paper from the paper storage unit, the paper supply roller that receives the paper from the pickup roller and carries it out of the paper storage unit, and contacts and overlaps the paper supply roller In a paper feeding device having a separation roller for separating the separated paper and a cleaning roller for contacting the separation roller and cleaning the surface thereof, a driving roller provided on a support shaft of the separation roller, and a support for the cleaning roller The cleaning roller is provided with a driven roller that is in contact with the peripheral surface of the drive roller, and the cleaning roller obtains rotational power from the support shaft of the separation roller by friction driving of the driven roller by the drive roller. There is no need to arrange a plurality of gears between the shaft and the support shaft of the cleaning roller. Thereby, it is not necessary to secure the arrangement space of the gear group for driving the cleaning roller. Therefore, it is possible to provide a paper feeding device that can continuously clean the surface of the separation roller with a compact configuration and can reliably separate and supply the paper one by one.

  Further, since the diameter of the driving roller and the diameter of the driven roller are different from each other, it is possible to easily set a peripheral speed difference between the separation roller and the cleaning roller. Accordingly, the cleaning performance for the separation roller can be improved without greatly increasing the arrangement space of the members related to the driving of the cleaning roller, and the effect of separating and supplying the sheets one by one can be further enhanced. is there.

  In the present invention, since the paper feeding device is mounted on the image forming apparatus, the surface of the separation roller can be continuously cleaned with a compact structure, and the sheets can be reliably fed one by one. A high-performance image forming apparatus that can be supplied separately can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an image output operation of an image forming apparatus equipped with a sheet feeding device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper feed cassette 20 that is a paper storage unit is disposed below the inside of the main body 2 of the printer 1. The paper P is stacked and accommodated inside the paper feed cassette 20. A paper feeding device 30 is disposed above the downstream portion of the paper feeding cassette 20 in the paper conveyance direction. The sheet feeding device 30 feeds the sheet P toward the upper right of the sheet feeding cassette 20 in FIG. The paper feed cassette 20 can be pulled out horizontally from the front side of the main body 2, that is, from the right side in FIG.

  A paper feed path 3, a registration roller 4, an image forming unit 40, and a transfer unit 50 are disposed downstream of the paper feed cassette 20 in the paper carrying direction. The paper P sent out from the paper feed cassette 20 reaches the registration roller 4 through the paper feed paper conveyance path 3. The registration roller 4 corrects the oblique feeding of the paper P, measures the timing with the toner image formed by the image forming unit 40, and sends the paper P to the transfer unit 50.

  Image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the printer 1, and lasers controlled by the optical unit 5 provided above the image forming unit 40 based on the image data. Light L (dashed line in the figure) is irradiated. As a result, in the image forming unit 40, an electrostatic latent image of the original image is formed on the photosensitive drum 41, which is an image carrier, and a toner image is developed from the electrostatic latent image. The toner image is transferred to the paper P sent in synchronization by the registration roller 4 at a transfer nip portion formed by press contact between the photosensitive drum 41 and the transfer roller 51 of the transfer portion 50.

  A fixing unit 6, a discharge paper transport path 7, and a paper discharge unit 8 are disposed downstream of the image forming unit 40 and the transfer unit 50 in the paper transport direction. The sheet P carrying the unfixed toner image in the transfer unit 50 is sent to the fixing unit 6 and the toner image is fixed by the heat roller. The paper P discharged from the fixing unit 6 is sent upward through a paper discharge path 7 for discharge, and is discharged out of the apparatus from a paper discharge unit 8 provided on the upper surface of the main body 2.

  Next, the configuration of the paper feed cassette 20 and the paper feed device 30 mounted on the printer 1 will be described in more detail with reference to FIG.

  As shown in FIG. 1, the main part of the paper feed cassette 20 is constituted by a paper feed tray 21. The paper feed tray 21 is constituted by a flat box having an open top surface, and stacks and accommodates sheets P such as cut paper before printing from the top surface direction.

  A lift plate 22 is provided on the inner bottom surface of the paper feed tray 21. The sheets P are stacked on the upper surface of the lift plate 22. The lift plate 22 is supported at its upstream end in the sheet feeding direction, that is, the left end in FIG. 1, on both side walls in the sheet width direction of the sheet feeding tray 21 perpendicular to the sheet feeding direction. The lift plate 22 can rotate in the vertical plane with the support portion as the center and the downstream end as a free end.

  A spring 23 is provided between the lift plate 22 and the inner bottom surface of the paper feed tray 21 below the downstream portion in the paper feed direction. The spring 23 biases the downstream portion of the lift plate 22 to displace upward. The lift plate 22 is lifted at its downstream portion by the action of the spring 23, and the uppermost layer of the sheet bundle abuts on the paper feeding device 30 provided above the downstream portion of the paper feed cassette 20. Displace to position. The sheets P on the lift plate 22 are separated one by one by the sheet feeding device 30 and sent out to the outside of the sheet feeding cassette 20, that is, toward the upper right in FIG.

  As shown in FIG. 1, the paper feed device 30 includes a pickup roller 31, a paper feed roller 32, a separation roller 33, and a cleaning roller 34 that is a cleaning member for the separation roller 33. Among these roller members, the pickup roller 31 and the paper feed roller 32 are attached to the main body 2, and the separation roller 33 and the cleaning roller 34 are attached to the paper feed cassette 20.

  The pickup roller 31 is provided above the downstream portion of the lift plate 22. The downstream portion of the paper P loaded on the paper feed tray 21 is lifted by the lift plate 22 to which the elastic force of the spring 23 is applied, and the uppermost layer of the paper P contacts the pickup roller 31 from below. The uppermost layer of the paper P is transferred to the paper feed roller 32 by the pickup roller 31 and is conveyed to the outside of the paper feed cassette 20 by the paper feed roller 32.

  The paper feed roller 32 is disposed on the downstream side of the pickup roller 31 so that the lower surface of the paper feed roller 32 protrudes into the paper feed paper conveyance path 3. The paper feed roller 32 is connected to a motor (not shown) and is rotated counterclockwise in FIG. Note that the pickup roller 31 is not connected to a motor. A drive mechanism (not shown) for the pickup roller 31 is disposed between the paper feed roller 32 and the pickup roller 31, and the paper feed roller 32 and the pickup roller 31 are connected via this drive mechanism. When the paper feed roller 32 is rotated by the motor by the drive mechanism of the pickup roller 31, the pickup roller 31 is also rotated in the same direction as the paper feed roller 32.

  The separation roller 33 is provided below the paper feed roller 32. Further, the separation roller 33 is biased upward by the action of a spring 36 (see FIG. 2) that is a biasing member, and is in contact with the paper feed roller 32. The paper P is inserted through a conveyance nip formed by the separation roller 33 and the paper feed roller 32 in contact with each other. A motor (not shown) is connected to the separation roller 33. Then, the separation roller 33 is moved counterclockwise in FIG. The rotational force is acting.

  The separation roller 33 is provided with a torque limiter (not shown) between the shaft of the motor and the drive shaft of the motor. When the sheet P does not exist in the conveyance nip formed by the contact between the separation roller 33 and the sheet feeding roller 32 or when only one sheet P enters, the separation roller 33 has a torque that is equal to or higher than the torque limiter setting torque. The separation roller 33 rotates in the direction of feeding the paper P to the outside of the paper feed cassette 20 according to the paper feed roller 32.

  However, when a plurality of sheets of paper P enter the transport nip, the torque applied to the separation roller 33 does not exceed the set torque of the torque limiter. It rotates in the direction of moving in the opposite direction with respect to the surface of 32, that is, in the direction of returning the overlapped lower sheet P to the sheet feed tray 21. As a result, the overlapped lower side paper P is not sent out, so that it is possible to prevent the problem of double feeding in which the paper P is overlapped and sent.

  As shown in FIG. 1, the cleaning roller 34 is provided below the separation roller 33 and is in contact with the separation roller 33. The cleaning roller 34 receives rotational power from the separation roller 33, and the surface of the contact portion with the separation roller 33 rotates in a direction that moves in the same direction with respect to the surface of the separation roller 33. Thereby, the cleaning roller 34 can clean the paper dust attached to the surface of the separation roller 33 so as to be scraped off.

  Next, a detailed configuration of the sheet feeding device 30 around the separation roller 33 and the cleaning roller 34 will be described with reference to FIGS. 2 is a partially enlarged left side view of the vertical section showing a part of the paper feeding device of the printer, FIG. 3 is a perspective view of a part of the paper feeding device shown in FIG. 2, and FIG. 4 is the same as FIG. FIG. 5 is a partially enlarged top view around the separation roller and the cleaning roller, and FIG. 6 is a perspective view around the cleaning roller. In contrast to FIG. 3, the drawing of the holder is omitted in FIG.

  As shown in FIGS. 2 and 3, the sheet feeding device 30 includes a holder 35 that holds the separation roller 33 and a spring 36 that is a biasing member in the vicinity of the separation roller 33.

  The holder 35 is disposed immediately below the paper feed roller 32. The holder 35 holds the separation roller 33 rotatably by a support shaft 33 a, and the separation roller 33 protrudes upward from the upper surface of the holder 35 into the paper feed path 3 and is in contact with the paper feed roller 32. .

  As shown in FIG. 2, the holder 35 includes a support shaft 35 a that extends at a right angle to the paper conveyance direction and extends horizontally on the downstream side of the paper conveyance direction where the separation roller 33 is held. The support shaft 35a is isolated from the rotation center of the separation roller 33 and has a rotation center parallel to the rotation center. The holder 35 is supported by the frame 20a of the paper feed cassette 20 so that the portion holding the separation roller 33 can swing within a vertical plane around the support shaft 35a.

  The spring 36 is disposed on the upstream side in the sheet conveyance direction with respect to the support shaft 35 a of the holder 35 with a portion for holding the separation roller 33, and below the holder 35. The spring 36 is disposed between the holder 35 and the frame 20a of the paper feed cassette 20, and urges the holder 35 upward. As a result, the holder 35 is urged to rotate clockwise in FIG. 2 about the support shaft 35 a, and the separation roller 33 is pressed against the paper feed roller 32.

  As shown in FIGS. 2 to 4, the cleaning roller 34 is disposed below the separation roller 33 and is held by the holder 35 with its support shaft 34 a.

  As shown in FIGS. 3 to 6, the sheet feeding device 30 includes a driving roller 37 on the support shaft 33 a of the separation roller 33 and a driven roller 38 on the support shaft 34 a of the cleaning roller 34. Both the driving roller 37 and the driven roller 38 are made of rubber on their peripheral surfaces.

  Both the separation roller 33 and the drive roller 37 have the same rotation center and are configured with substantially the same diameter. Similarly, both the cleaning roller 34 and the driven roller 38 have the same rotation center and are configured with substantially the same diameter. The diameter of the driving roller 37 and the diameter of the driven roller 38 are different from each other. The peripheral surface of the driven roller 38 is in contact with the peripheral surface of the drive roller 37. Note that the coefficient of friction between the surface of the driving roller 37 and the surface of the driven roller 38 is larger than the coefficient of friction between the surface of the separation roller 33 and the surface of the cleaning roller 34.

  Accordingly, the cleaning roller 34 obtains rotational power from the support shaft 33 a of the separation roller 33 by the friction drive of the driven roller 38 by the driving roller 37.

  As described above, the pickup roller 31 that feeds the paper P from the paper feed cassette 20 that is the paper storage unit, the paper feed roller 32 that receives the paper P from the pickup roller 31 and carries it out of the paper feed cassette 20, In the paper feeding device 30 provided with a separation roller 33 that separates the overlapping paper P in contact with the paper feed roller 32 and a cleaning roller 34 that contacts the separation roller 33 and cleans the surface thereof, the separation roller 33 is provided. A driving roller 37 provided on the support shaft 33 a and a driven roller 38 provided on the support shaft 34 a of the cleaning roller 34 and in contact with the peripheral surface of the driving roller 37. The cleaning roller 34 is a driven roller 38 driven by the driving roller 37. The rotational power is obtained from the support shaft 33a of the separation roller 33 by the friction drive of Between the support shaft 34a of a cleaning roller 34, it is not necessary to arrange a plurality of gears. Thereby, it is not necessary to secure the arrangement space of the gear group for driving the cleaning roller 34. Accordingly, it is possible to provide a sheet feeding device 30 that can continuously clean the surface of the separation roller 33 with a compact configuration and can reliably separate and supply the sheets P one by one. Can do.

  Further, since the diameter of the driving roller 37 and the diameter of the driven roller 38 are different from each other, it is possible to easily set a peripheral speed difference between the separation roller 33 and the cleaning roller 34. Thereby, the cleaning performance for the separation roller 33 can be improved without greatly increasing the arrangement space of the members related to the driving of the cleaning roller 34, and the effect of separating and supplying the paper P one by one is further enhanced. Is possible.

  Further, in the present invention, since the paper feeding device 30 is mounted on the image forming apparatus 1, the surface of the separation roller 33 can be continuously cleaned with a compact configuration, and one sheet P can be reliably obtained. It is possible to obtain a high-performance image forming apparatus 1 that can be supplied separately.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, the printer 1 equipped with the paper feeding device 20 is an image forming apparatus for monochrome printing using only black toner in the above embodiment, but is not limited to such a model, and an intermediate transfer belt is used. It may be a tandem type or rotary rack type image forming apparatus for color printing that is provided and can form an image by superimposing a plurality of colors.

  In the sheet feeding device 20, the driving roller 37 has the same diameter as the separation roller 33, and the driven roller 38 has the same diameter as the cleaning roller 34. The sizes of these members are as described above. The diameter of the driving roller 37 may be different from the diameter of the separation roller 33, and the driven roller 38 may be different from the diameter of the cleaning roller 34. Further, although the diameter of the driving roller 37 and the diameter of the driven roller 38 are different from each other, they may be the same diameter.

  The present invention can be used in a sheet feeding device that includes a separation roller that separates overlapping sheets in contact with the sheet feeding roller, and a cleaning roller that contacts the separation roller and cleans the surface thereof.

It is a model vertical section left side view of a printer carrying a paper feeding device according to an embodiment of the present invention. FIG. 2 is an enlarged left side view of a part of the sheet feeding device in FIG. FIG. 3 is a perspective view of a part of the sheet feeding device illustrated in FIG. 2 as viewed from above. FIG. 4 is a perspective view of a part of the same sheet feeding apparatus as that in FIG. 3 as viewed from above, and is viewed from a direction different from FIG. FIG. 4 is a partially enlarged top view around the separation roller and the cleaning roller in FIG. 3. FIG. 5 is a perspective view around the cleaning roller of FIG. 4.

Explanation of symbols

1 Printer (image forming device)
2 Main body 20 Paper feed cassette (paper compartment)
DESCRIPTION OF SYMBOLS 21 Paper feed tray 30 Paper feed device 31 Pickup roller 32 Paper feed roller 33 Separation roller 33a Support shaft 34 Cleaning roller 34a Support shaft 35 Holder 36 Spring 37 Drive roller 38 Driven roller

Claims (3)

A pickup roller that feeds paper from the paper storage unit, a paper supply roller that receives paper from the pickup roller and carries it out of the paper storage unit, and a separation roller that separates the overlapping paper in contact with the paper supply roller In a paper feeding device provided with a cleaning roller that contacts the separation roller and cleans the surface thereof,
A driving roller provided on the support shaft of the separation roller and a driven roller provided on the support shaft of the cleaning roller and in contact with the peripheral surface of the drive roller are separated by the friction drive of the driven roller by the drive roller. A sheet feeding device characterized in that rotational power is obtained from a support shaft of a roller.   The sheet feeding device according to claim 1, wherein a diameter of the driving roller and a diameter of the driven roller are different from each other.   An image forming apparatus comprising the paper feeding device according to claim 1.

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