JP2003165643A - Paper feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder capable of suppressing vibration and noise in feeding paper sheets. <P>SOLUTION: An integral paper feed unit 32 is constituted by connecting respective both end surfaces of an upper retaining member 29 retaining a pickup roller and a paper feed roller, and a lower retaining member 30 retaining a separating roller by connecting members 31. A leaf spring 35 is attached to an approximately longitudinal center of the upper retaining member 29. The respective connecting members 31 are fixed to a copying machine body and the approximately longitudinal center of the upper retaining member 29 is engaged with the copying machine body by the leaf spring 35 by a prescribed pushing pressure. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an image forming apparatus such as a copying machine, a printer, and a facsimile, and relates to a paper feeding device for feeding the contained paper.

[0002]

2. Description of the Related Art Conventionally, a pickup roller for sending out a paper stored in a paper cassette, a paper feed roller for carrying the paper sent from the pickup roller, and a pickup roller pressed against the paper feed roller. A copying machine is known which includes a separating roller for separating the second and subsequent sheets from the first sheet when two or more sheets are fed out from the sheet (double feeding) and preventing the double feeding. ing.

In this type of copying machine, for example, both ends of a pickup roller and a paper feed roller are held by a first holding member which is long in the axial direction of these rollers, and both ends of the separating roller are A second roller that is long in the axial direction of the roller
There is a structure in which both the holding members are held by a holding member and both longitudinal end portions of the holding members are connected by connecting members to be fixed to the main body of the copying machine. By thus forming the paper feed mechanism as an integrated paper feed unit, maintenance of the paper feed mechanism can be facilitated.

The separating roller includes, for example, a rotating shaft to which a driving force is applied in the direction opposite to the sheet conveying direction, and a separating roll body connected to the rotating shaft via a torque limiter and pressed against the paper feeding roller. When the number of sheets sent from the pickup roller is one, the torque transmitted from the pressure-feeding feed roller to the separating roll body becomes a certain value or more, so that the torque of the rotating shaft is not transmitted to the separating roll body. ,
The separating roll body is rotated in the forward direction in which the sheet is conveyed.
On the other hand, when the sheets are fed from the pick-up roller, the first sheet is fed by the sheet feeding roller, and the second and subsequent sheets rub against the first sheet,
The torque transmitted from the paper feeding roller to the separating roll body becomes a certain value or less. In this case, the torque of the rotating shaft is transmitted to the separating roll body, so that the separating roll body is rotated in the reverse direction opposite to the direction in which the sheet is conveyed, and the second and subsequent sheets are in the opposite direction to the conveying direction. Returned to. When the paper is returned, the rotation direction of the separating roll body returns to the normal rotation direction, and the paper is returned to the normal rotation direction again.
When the sheets after the first sheet are conveyed, the separation roll body is turned over. That is, when the sheets are fed from the pick-up roller, the separating roll body repeats the forward rotation and the reverse rotation, so that the second and subsequent sheets are fed one by one.
Separated from the first sheet.

The sheet feeding roller and the separating roller are, for example, EPDM (ethylene-propylene-diene-methylen), respectively.
e).

[0006]

However, when sheets are fed from the pick-up roller repeatedly and the separation roller repeats forward rotation and reverse rotation, the separation roller is moved to 1 immediately before the rotation direction is switched from reverse rotation to normal rotation. The sheet of paper is rubbed in the direction opposite to the sheet conveying direction. As a result, a rubbing noise may be generated, and further vibration may be generated in the entire first and second holding members.

Particularly, when the paper feed roller and the separation roller are formed of EPDM having a relatively large friction resistance, rubbing noise and vibration are likely to occur. Further, when vibrations are generated in the entire first and second holding members, the noise of rubbing between the sheet and the separation roller is increased, which may cause noise. The present invention has been made under such a background, and an object thereof is to provide a sheet feeding device capable of suppressing vibration and noise during sheet feeding.

[0008]

In order to achieve the above object, the invention according to claim 1 directs the sheet accommodated in the image forming apparatus (1) toward the image forming section (5). A device (32) for feeding out, a paper feed roller (24) for conveying the contained sheets one by one.
And a member long in the axial direction of the paper feed roller,
A first holding member (2) that holds both ends of the paper feed roller.
9) and a pair of the above-mentioned paper feed rollers, and when the sheets are fed in a double feed, the separation for separating the second and subsequent sheets from the first sheet to prevent the double feed A roller (27), a member that is long in the axial direction of the separating roller, and a second holding member (30) that holds both ends of the separating roller, and a length of the first holding member and the second holding member. A connecting member (31) for connecting both ends in the direction to each other to fix the image forming apparatus main body, and the first holding member and the second holding member with the connecting member fixed to the image forming apparatus main body. The sheet feeding device is characterized by including an engaging member (35) for engaging at least one of the approximately center in the longitudinal direction and the image forming apparatus main body (37) with a predetermined pressing force.

The alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies in this section below. The separating roller includes, for example, a rotating shaft to which a driving force is applied in a direction opposite to the paper conveying direction, and a separating roll body connected to the rotating shaft via a torque limiter and pressed against the paper feeding roller. When the number of sheets (sheets) sent from the pickup roller is one, the torque transmitted from the pressure-feeding feed roller to the separating roll body exceeds a certain value, so that the torque of the rotating shaft is distributed to the separating roll body. Without being transmitted, the separating roll body is rotated in the forward direction in which the sheet is conveyed. On the other hand, when the paper is double-fed from the pickup roller, the first paper is fed by the paper feed roller and the second and subsequent papers rub against the first paper, so that the paper feed roller The torque transmitted from the separation roll body to the separation roll body becomes a certain value or less. In this case, the torque of the rotating shaft is transmitted to the separating roll body, and the separating roll body is rotated in the reverse direction opposite to the direction in which the sheet is conveyed. That is, when the sheets are fed from the pick-up roller, the separation roll body repeats the forward rotation and the reverse rotation, so that the second and subsequent sheets are separated from the first sheet.

According to the structure of the present invention, the first holding member and the second holding member are connected by the connecting member to be fixed to the main body of the image forming apparatus, and further the engaging member is used to connect the first holding member and the second holding member. The vibration of each holding member can be suppressed by engaging at least one of the two holding members in the longitudinal direction substantially in the center thereof with the image forming apparatus main body with a predetermined pressing force. Further, by suppressing the vibration of each holding member, it is possible to prevent the rubbing noise between the first sheet and the separating roller from being increased and becoming a noise at the time of double feeding.

According to a second aspect of the present invention, the engaging member (3
(5) is a sheet feeding device according to claim 1, wherein the sheet feeding roller and the separating roller apply a pressing force along a direction substantially the same as the lined direction. Usually, the vibration of each holding member occurs in the direction in which the sheet feeding roller and the separating roller that are in pressure contact with each other are aligned. According to the configuration of the present invention,
Since the pressing force is applied by the engaging member in a direction substantially the same as the direction in which the sheet feeding roller and the separating roller are lined up, it is possible to suitably suppress vibration.

According to a third aspect of the present invention, a pickup roller for feeding the sheet held in the first holding member (29) and stored in the image forming apparatus (1) to the paper feed roller (26) side. The sheet feeding device according to claim 1 or 2, further comprising (25). According to this configuration, the paper feed roller, the separation roller, and the pickup roller, which form the paper feed mechanism for feeding the paper stored in the image forming apparatus toward the image forming unit, are connected via the connecting member. Since the unit can be integrated, maintenance can be facilitated.

If the engaging member (35) is composed of a leaf spring as in the fourth aspect of the invention, the vibration of each holding member can be suppressed more preferably.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic sectional view showing an internal configuration of a copying machine 1 according to an embodiment of the present invention. Note that, in FIG. 1, the front side of the paper surface is referred to as the front and the rear side of the paper surface is referred to as the rear side. The copying machine 1 is a so-called digital copying machine, and its outer shape is defined by a substantially rectangular housing 2 that covers a skeleton member (not shown) forming the skeleton. Inside the housing 2, a reading device 3 for reading an image of a document, a paper feed unit 4 for feeding a transfer sheet, and a toner image based on the image of the document read by the reading device 3 on the fed sheet. An image forming unit 5 for transferring the toner image, a fixing device 6 for fixing the toner image transferred on the paper, and the like are provided.

On the upper surface of the housing 2, a document set on a document tray 7A is automatically fed to cause the reading device 3 to read the image.
Are arranged. For example, the rear end of the automatic document feeder 7 is rotatably attached to the upper surface of the housing 2. A transparent contact glass 8 is arranged above the reading device 3. This contact glass 8
The upper surface thereof constitutes a mounting table for setting a document, and when the automatic document feeder 7 is closed, the upper surface of the contact glass 8 is covered with the automatic document feeder 7. . The user can use the automatic document feeder 7
In addition to setting the original on the original tray 7A, the automatic original feeder 7 is opened, and the original is placed on the contact glass 8 with its front surface facing downward. You can set one by one.

After setting the original on the original tray 7A or the contact glass 8, the user presses a start button (not shown) on the operation panel provided on the front side of the upper surface of the housing 2, for example. The reading of the document by the reading device 3 can be started. The image forming section 5 is arranged in the upper part of the housing 2 and includes a photosensitive drum 9, a developing device 10, a transfer device 11, a main charger 12 and a cleaning device 13. The photosensitive drum 9 is, for example, a cylindrical body extending in the front-rear direction, and is rotationally driven clockwise in FIG. The photoconductor drum 9 has a photoconductor layer on its surface, and the photoconductor layer is uniformly charged by the discharge of the main charger 12 during image formation.

A laser scanning unit (LSU) 14 is arranged above the image forming section 5. The surface of the photosensitive drum 9 charged by the main charger 12 is selectively exposed by the irradiation light from the laser scanning unit 14 based on the image of the original read by the reading device 3. As a result, a so-called electrostatic latent image is formed on the surface of the photosensitive drum 9. Toner is attached by the developing device 10 to the surface of the photosensitive drum 9 on which the electrostatic latent image is formed, and a toner image based on the image of the original is formed. When the photoconductor drum 9 is further rotated, the transfer device 11 functions to transfer the toner image onto the conveyed sheet. The toner remaining on the surface of the photosensitive drum 9 after the transfer of the toner image is collected by the cleaning device 13.

The sheet on which the toner image is transferred is fixed by the fixing device 6.
And is subjected to a fixing process by the fixing device 6, and then discharged from the discharge roller 15 to the discharge tray 16 outside the housing 2. On the right side in the housing 2, a paper transport path 17 for guiding the paper from the paper feed section 4 to the image forming section 5 extends in the vertical direction. In the paper transport path 17,
Immediately upstream of the image forming unit 5, a registration roller 18 for delivering the paper sent from the paper feeding unit 4 toward the image forming unit 5 at a predetermined timing is arranged. Further, in the middle of the paper transport path 17, a plurality of transport rollers 19 for transporting the paper to the registration roller 18 side are arranged.

The paper is fed from the paper feeding section 4 and is fed to the paper feeding path 17
The sheet conveyed upward through the sheet is temporarily stopped when the leading end of the sheet reaches the registration roller 18. Then, the rotation of the registration roller 18 is started so that the sheet arrives at the image forming unit 5 at the timing when the toner image formed on the surface of the photoconductor drum 9 in the above-described mode comes to a position facing the transfer device 11. It is supposed to be done. The paper feed unit 4 is arranged in the lower portion of the housing 2, and has two paper cassettes 20 arranged vertically above the paper feed unit 4 and two paper cassettes 20 arranged in the lower portion of the paper feed unit 4 side by side. And two paper decks 21. The paper cassette 20 and the paper deck 21 are respectively slidable in the front-rear direction, and the user can pull them out to the front side to supply paper.

The paper cassette 20 is, for example, 500-80.
Up to 0 sheets of paper can be stored, and at the time of paper feeding, one end of the stored paper is lifted by the lift plate 22, and one end of the uppermost paper is pressed against the pickup roller 23. ing. By the action of the pickup roller 23, the sheets accommodated in the sheet cassette 20 are sent out one by one from the top, and are conveyed to the sheet conveying path 17 through the sheet feeding roller 24.

On the other hand, the paper deck 21 is, for example, 1000
Up to 1,500 sheets of paper can be stored, and the sheets can be stored on a lift plate (not shown) that can be vertically moved while maintaining a substantially horizontal position. At the time of paper feeding, the accommodated sheets are lifted upward by a lift plate while being kept substantially horizontal, and one end of the uppermost sheet is pressed against the pickup roller 25. By the action of the pickup roller 25, the sheets accommodated in the sheet deck 21 are sent out one by one from the top, and are conveyed to the sheet conveying path 17 through the sheet feeding roller 26.

Normally, the paper deck 21 accommodates paper of a size that is frequently used (for example, Japanese Industrial Standard (JIS) A-row No. 4 or B-row No. 5). FIG. 2 is an enlarged cross-sectional view of the essential parts showing the configuration of the paper feed mechanism for feeding the paper from the paper feed cassette 20. The pickup roller 23 is
For example, it includes a substantially cylindrical pickup roll body 23A formed by EPDM and a rotary shaft 23B that rotatably holds the pickup roll body 23A. Rotating shaft 23B
A drive mechanism (not shown) for rotating the pickup roller 23 is connected to one end of the. At the time of sheet feeding, the pickup roller 23 is rotated counterclockwise in FIG. 2 by, for example, rotationally driving a motor included in the drive mechanism.

On the other hand, the paper feed roller 24 is, for example, EPDM.
And a rotation shaft 24B that holds the paper feed roll body 24A so as to be rotatable and that extends substantially parallel to the rotation shaft 23B of the pickup roller 23. One end of the rotary shaft 24B is connected to the drive mechanism via a gear, for example, and is rotated counterclockwise in FIG. 2 together with the pickup roller 23 during paper feeding. A separating roller 27 is arranged below the paper feeding roller 24. When two or more sheets are fed from the pickup roller 23 (double feed), the separating roller 27 separates the second and subsequent sheets from the top (first) sheet to prevent double feed. For the sake of
For example, a roughly cylindrical separating roll body 27A formed by EPDM, and a rotating shaft 2 that holds the separating roll body 27A and extends substantially parallel to the rotating shaft 24B of the sheet feeding roller 24.
7B and. One end of the rotary shaft 27B is connected to the drive mechanism, and a counterclockwise drive force in FIG. 2 is applied at the time of sheet feeding.

The rotating shaft 27B of the separating roller 27 is the bearing 2
It is urged upward by the compression spring 28 via 7C. As a result, the separating roll body 27A becomes the paper feed roll body 2
It is pressed against 4A with a predetermined pressure (nip pressure). The separating roll body 27A and the rotating shaft 27B are connected to each other via a torque limiter (not shown). Normally, when the torque transmitted from the pressure-contacted paper feed roller 24 to the separating roll body 27A becomes a certain value or more, the rotating shaft 27B
Is not transmitted to the separating roll body 27A, and the separating roll body 27A is in the opposite direction (clockwise) from the rotating shaft 27B.
It is designed to be rotated.

When the number of sheets sent from the pickup roller 23 is one, the roll body 2 is separated from the sheet feed roller 24.
The torque transmitted to 7A remains above a certain value, and the separating roll body 27A is rotated in the normal rotation direction (clockwise direction) in which the sheet is conveyed as usual. On the other hand, when the sheets are fed from the pickup roller 23, the first sheet is fed by the sheet feeding roller 24, and the second and subsequent sheets are rubbed against the first sheet. The torque transmitted from the paper roller 24 to the separating roll body 27A becomes a certain value or less. In this case, the torque of the rotating shaft 27B is transmitted to the separating roll body 27A, whereby the separating roll body 27A is rotated in the reverse direction (counterclockwise direction) opposite to the direction in which the paper is conveyed, and the second and subsequent sheets are rotated. The paper is returned in the direction opposite to the transport direction. When the paper is returned, the rotation direction of the separating roll body 27A returns to the normal rotation direction, and when the second and subsequent sheets of paper are conveyed again, the separating roll body 27A is reversed. That is, when the sheets are fed from the pick-up roller 23, the separation roll body 27A repeats the forward rotation and the reverse rotation, so that the second and subsequent sheets are separated from the first sheet.

In this embodiment, the pickup roller 23
The paper feed roller 24 is held by the upper holding member 29. The upper holding member 29 is, for example, a metal member that is long in the axial direction of the pickup roller 23 and the paper feed roller 24, and is the rotating shaft 23 of the pickup roller 23.
It holds both end portions of B and both end portions of the rotation shaft 24B of the paper feed roller 24. The pickup roll body 23A and the paper feed roll body 24A are attached so as to project downward from the lower surface of the upper holding member 29.

On the other hand, the separating roller 27 is provided with a lower holding member 30.
Is held by. The lower holding member 30 is, for example, a metal member that is long in the axial direction of the separating roller 27,
Both ends of the rotary shaft 24B of the separating roller 24 are held. The separating roll body 27A is attached in a state of protruding upward from the upper surface of the lower holding member 30. The upper holding member 29 and the lower holding member 30 are vertically arranged side by side with a predetermined gap therebetween, and the paper delivered from the paper cassette 20 passes through the gap between the two holding members 29 and 30 and conveys the paper. You are led to road 17.

FIG. 3 is a schematic perspective view of the sheet feeding unit 32 as seen from diagonally above. Hereinafter, description will be made with reference to FIGS. 2 and 3. The upper holding member 29 and the lower holding member 30 are
Both ends in the longitudinal direction are connected by a connecting member 31 to form an integral sheet feeding unit 32. As a result, the paper feed roller 26, the separation roller 27, and the pickup roller 23, which form a paper feed mechanism for feeding the paper stored in the paper cassette 20 toward the image forming unit 5, can be integrated into a unit. Therefore, maintenance can be facilitated.

Each connecting member 31 is a metal plate-like member attached to the end surfaces of the upper holding member 29 and the lower holding member 30, and has an end portion on the side of the paper transport path 17 (right front side in FIG. 3). Bending piece 3
1A is formed. Each connecting member 31 is connected to the upper holding member 29 and the lower holding member 3 by, for example, four screws 33.
It is attached to the end face of 0. In the bent piece 31A of each connecting member 31, two through holes 34 are formed vertically. Screws (not shown) are respectively passed through these through holes 34 and are fastened to a skeleton member of the copying machine 1 (for example, a main body side plate forming a side skeleton of the main body of the copying machine 1), so that the sheet feeding unit 32 is inside the copying machine 1. Can be fixed at a predetermined mounting position.

A leaf spring 35 is attached to the end surface of the upper holding member 29 on the side of the sheet conveying path 17 by, for example, a screw 36 at approximately the center in the longitudinal direction. The leaf spring 35 is
For example, it is a plate-shaped member formed of stainless steel or the like, and is bent in two steps to have a shape formed by three bent pieces. The bent piece 35A at the tip of the leaf spring 35 holds the leaf spring 35 on the upper holding member 29.
When attached to the upper holding member 29, it is substantially parallel to the upper surface of the upper holding member 29. The bent piece 35A constitutes a skeleton member of the copying machine 1 and holds the conveying roller 19 while the paper feeding unit 32 is fixed in the copying machine 1.
The lower surface of is pressed upward with a predetermined pressing force (see FIG. 2).

In the present embodiment, the upper holding member 29 and the lower holding member 30 are connected by the connecting member 31 and fixed to the main body of the copying machine 1, and then the upper holding member 29 is further fixed by the leaf spring 35.
Each holding member 2 is engaged with the main body (stay 37) of the copying machine 1 with a predetermined pressing force at substantially the center in the longitudinal direction of the holding member 2.
The vibrations of 9 and 30 can be suppressed. Further, by suppressing the vibration of the holding members 29 and 30, it is possible to prevent the friction noise between the first sheet and the separating roller 27 from becoming large and becoming a noise at the time of double feeding.

Further, the upper holding member 29 and the lower holding member 30
And can be prevented from resonating. Usually, each holding member 29,
The vibration of 30 occurs in the direction in which the paper feed roller 26 and the separation roller 27, which are in pressure contact with each other, are aligned. In the present embodiment, since the leaf spring 35 applies a pressing force in a direction (vertical direction) substantially the same as the direction in which the sheet feeding roller 26 and the separating roller 27 are arranged, the vibration can be suppressed appropriately. .
The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.

For example, the leaf spring 35 is not limited to the upper holding member 29, but may be attached to the lower holding member 30 substantially at the center in the longitudinal direction, or may be attached to both the upper and lower holding members 29 and 30. Good. In addition, the leaf spring 35 is attached to the stay 3
7 may be attached to press the upper holding member 29 downward. The member that engages the paper feeding unit 32 and the main body of the copying machine 1 is not limited to the leaf spring 35 as long as it applies a predetermined pressing force, and for example, simply connects the paper feeding unit 32 and the main body of the copying machine 1. A fixed plate,
It may be a compression spring or the like.

The paper feed unit 32 is not limited to the paper cassette 20, and may be applied to the paper deck 21, for example. Although the digital copying machine 1 has been described as an embodiment of the present invention, the present invention is not limited to the digital copying machine and can be applied to a so-called analog copying machine. Further, the invention can be applied not only to a copying machine but also to an image forming apparatus such as a printer or a facsimile.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an internal configuration of a copying machine according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an essential part showing the configuration of a paper feed mechanism for feeding a paper from a paper feed cassette.

FIG. 3 is a schematic perspective view of the sheet feeding unit as seen from diagonally above.

[Explanation of symbols]

1 Copier 5 Image forming section 23 Pickup roller 26 paper feed rollers 27 Separation roller 29 Upper holding member 30 Lower holding member 31 Connection member 32 paper feed units 35 leaf spring 37 stay

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideki Kitagawa             1-22 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Prefecture             Kyocera Mita Co., Ltd. F term (reference) 3F343 FA02 FB02 FB03 FC01 FC28                       GA01 GA03 GB01 GC01 GD01                       HB03 HB04 HC04 HD17 JA14                       JD04 JD09 JD33 KB04 KB05                       KB13

Claims (4)

[Claims] 1. A device for feeding sheets contained in an image forming apparatus toward an image forming unit, and a sheet feeding roller for conveying the accommodated sheets one by one, and the sheet feeding roller. A member that is long in the axial direction of the sheet feeding roller and that is provided as a pair with the first holding member that holds both ends of the sheet feeding roller and the sheet feeding roller. A separating roller for separating the second and subsequent sheets from the first sheet to prevent double feeding, and a member that is long in the axial direction of the separating roller and that holds both ends of the separating roller. 2 holding members, a connecting member for connecting both ends of the first holding member and the second holding member in the longitudinal direction to each other and fixing them to the image forming apparatus main body, and the connecting member fixed to the image forming apparatus main body. State, the first holding member and And at least one substantially longitudinal center of the second holding member, and an image forming apparatus body, the sheet feeding apparatus which comprises an engagement member for engaging with a predetermined urging force. 2. The sheet feeding device according to claim 1, wherein the engaging member applies a pressing force along a direction substantially the same as a direction in which the sheet feeding roller and the separating roller are arranged side by side. apparatus. 3. The pickup roller according to claim 1, further comprising a pickup roller for feeding the sheet held in the first holding member and accommodated in the image forming apparatus to the paper feed roller side. Paper feeder. 4. The sheet feeding device according to claim 1, wherein the engaging member is formed of a leaf spring.