JP2000219347A - Sheet feeder and image forming device furnished with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder capable of easily changing separation pads, and provide an image forming device furnished with it. SOLUTION: A separation member 1 to separate sheets fed by a paper feeding roller 4 one piece by one and an energizing means 3 to energize the separation member 1 toward the paper feeding roller 4 are held integrally by a holding member 2 and free to connect and disconnect the separation member 1, and this holding member 2 is installed on a device body 100 free to connect and disconnect to and from it. Thereafter, the separation member 1 is removed from the holding member 2 after removing the holding member 2 from the device body 100 when changing the separation member 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus and an image forming apparatus having the same, and more particularly, to an apparatus for separating and feeding sheets one by one by a separating member.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a printer, a facsimile, a copying machine or the like includes a sheet feeding device for separating sheets one by one and feeding them to an image forming section.
FIG. 6 is a diagram showing a schematic configuration of a laser printer as an example of such a conventional image forming apparatus. In FIG. 6, reference numeral 100 denotes a laser printer main body (hereinafter, referred to as an apparatus main body), and reference numeral 30 denotes a photosensitive drum. .

In this laser printer,
At the time of image formation, first, a latent image is formed on the photosensitive drum by laser exposure by the exposure unit 35, and then this latent image is developed into a toner image by the development unit 36. Next, after the toner image thus developed is transferred to the sheet P by the transfer device 37, the sheet P is heated and fixed by the fixing roller pair 31. The sheet P on which the toner image has been fixed is discharged onto the discharge tray 33 by the discharge rollers 32 and the like.

In FIG. 1, reference numeral 100A denotes a sheet feeding device. The sheet feeding device 100A is provided on a half-moon-shaped sheet feeding roller 4 having a missing portion and a cassette (not shown). Middle plate 6 pressed in the direction of paper roller
And a separation pad 1 rotatably held by the apparatus main body 100. The sheet P stacked on the intermediate plate is fed to the image forming unit 100B by the paper feed roller 4. I have.

On the other hand, FIG. 7 is a sectional view of a sheet feeding roller portion of the sheet feeding apparatus having the above-mentioned configuration. In FIG. 7, reference numeral 5 denotes a sheet feeding shaft for fixing the sheet feeding roller 4; The paper shaft 5 is rotatably supported by the apparatus main body 100.

Then, before printing, a middle plate pressing spring (not shown)
The intermediate plate 6 pressed in the direction of the paper feed roller by the
A cam (not shown) that rotates coaxially with the paper feed shaft 5 with the rotation of.
And the sheet P stacked on the middle plate
Are pressed against the paper feed roller 4. here,
The portion 4a of the sheet feed roller 4 which comes into contact with the sheet P is formed of a friction member such as rubber, and the uppermost sheet of the stacked sheet P is fed into the apparatus main body by utilizing the frictional force. It has become.

By the way, at the time of such feeding, the sheet P below the uppermost sheet may be dragged together with the uppermost sheet, and the sheets P may be fed twice. Therefore, conventionally, in order to prevent such double feeding, the separation pad 1 is provided on the downstream side of the middle plate 6 in the feeding direction.

Here, the separation pad 1 has a friction member 1a having a friction coefficient slightly smaller than that of the paper feed roller 4 attached to a separation pad holder 1c provided on the moving end side of a pad body 1b made of resin. It is a single component.

The separation pad 1 is urged by a pad pressing spring 3 so that the friction member 1a is pressed against the paper feed roller 4, so that a plurality of sheets P can be fed at one time. The sheet P below the top sheet
Is separated from the uppermost sheet by the frictional resistance of the friction member 1a, and only the uppermost sheet is fed into the apparatus main body 100.

The separation pressure spring 3 is a compression spring,
It is arranged on the back side of the separation pad holder opposite to the friction member 1a while being sandwiched by the apparatus main body 100.

On the other hand, the pad body 1b of the separation pad 1
Is provided with a rotation shaft 1d, and the separation pad 1 is rotatably supported by the rotation shaft 1d and a support portion (not shown) formed on the apparatus main body 100.
The rotation shaft 1d may cause a decrease in sheet feeding performance (such as double feeding or pad squeal) due to a change in the posture, pressure, etc. of the separation pad 1 due to the influence of the frictional force between the sheet P and the friction member 1a. In many cases, it is provided near the tangent L formed by the arc of the paper feed roller 4 upstream of the pressure contact point between the separation pad 1 (friction member 1a) and the paper feed roller 4 in the feeding direction.

[0012]

In such a conventional sheet feeding apparatus and an image forming apparatus having the same, if the friction member 1a of the separation pad 1 is deteriorated due to abrasion or the like, the sheet feeding performance is reduced. Therefore, the separation pad 1 is replaced.

However, in this replacement, for example, when the separation pad 1 is to be turned around the rotation shaft 1d to be removed, as shown in FIG. 5 and interfere with each other. For this reason, when the separation pad 1 is replaced, once the paper feed roller 4 or the paper feed shaft 5
Is detached from the apparatus main body 100, and then the separation pad 1 is detached from the apparatus main body 100.

Incidentally, even if the separation pad 1 can be removed without removing the paper feed roller 4 or the paper feed shaft 5, after the separation pad 1 is replaced, a separation pressure spring disposed on the back side of the separation pad 1 is used. It was difficult to arrange No. 3 in a regular position and posture.

Here, if the separation pressure spring 3 cannot be arranged in a proper position and posture, the separation pressure spring 3 is deformed and the separation pad 1 is pressed against the paper feed roller 4 with an appropriate pressure. Cannot be performed, and reliable sheet separation cannot be performed.

As described above, conventionally, when the separation pad 1 is replaced, a very large amount of labor and labor is required.

The present invention has been made in view of such circumstances, and has as its object to provide a sheet feeding apparatus capable of easily replacing a separation pad and an image forming apparatus having the same. It is.

[0018]

According to the present invention, there is provided a sheet feeding roller for feeding a sheet, a separating member for separating the sheets fed by the sheet feeding roller one by one, and the separating member for feeding the sheet. An urging means for urging toward the roller, and a holding member for holding the urging means and detachably holding the separating means, wherein the holding member is detachably attached to the apparatus main body. It is characterized by the following.

Further, the present invention is characterized in that the holding member can be attached and detached without the separating member coming into contact with the paper feed roller.

Further, according to the present invention, the sheet feeding roller is a roller having a missing portion, and when the sheet feeding roller is stopped with the missing portion facing the separating member, the sheet feeding roller is brought into contact with the separating member. The paper feed roller is provided in contact therewith.

Further, the present invention is characterized in that the material of the holding member and the material of the apparatus main body are different.

Further, the present invention is characterized in that the means for attaching the holding member to the apparatus main body is a screw or an elastic locking claw.

Further, as in the present invention, the separating member for separating the sheets fed by the paper feed roller one by one is urged toward the paper feed roller by the urging means, while the urging means is held. A holding member for detachably holding the separating member is detachably attached to the apparatus main body. Then, when replacing the separation member, the separation member is removed from the holding member after removing the holding member from the apparatus main body.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of a sheet feeding apparatus according to an embodiment of the present invention. Note that, in this figure, the same reference numerals as those in FIGS. 6 and 7 indicate the same or corresponding parts.

In the figure, reference numeral 7 denotes an intermediate plate pressing spring for pressing the intermediate plate 6 in the direction of the paper feed roller, and 9 denotes a paper feed cam fixed to the paper feed shaft 5. The pressed middle plate 6 is pressed against the sheet feed cam 9 at both ends. When the sheet feeding shaft 5 rotates at the time of sheet feeding, the sheet feeding cam 9 rotates simultaneously with the sheet feeding roller 4, and accordingly, the middle plate 6 rotates.
Starts rising, and the sheet P stacked on the middle plate comes into pressure contact with the sheet feeding roller 4 before the sheet P is fed by the sheet feeding roller 4.

The sheets P fed by the paper feed roller 4 are separated one by one by the separation pad 1.
Only the uppermost sheet is fed to a pair of conveying rollers 34 shown in FIG.

Here, while the sheet P is being conveyed by the conveying roller pair 34, the sheet feeding roller 4 (the sheet feeding shaft 5) is stopped with the missing circle portion 4a facing the separation pad 1, and thus is stopped. By stopping the sheet feeding roller 4 during the sheet conveyance, the sheet P, which is stacked on the middle plate, and is in the feeding standby state, is prevented from being fed into the apparatus main body 100.

During the sheet conveyance, the sheet P is sandwiched between the sheet feeding roller 8 provided on the sheet feeding roller 4 and the separation pad 1, and the sheet P is driven by the sheet feeding roller 8 by the conveying roller pair 34. While being sent to the apparatus main body 100.

On the other hand, FIG. 2 is a sectional view of a sheet feeding roller portion. In FIG. 2, reference numeral 2 denotes a separation pad holding member which is a holding member for holding the separation pad 1 which is a separation member. The holding member 2 is configured separately from the apparatus main body 100.

The separation pad holding member 2 is shown in FIG.
The rotation fulcrum hole 1c formed in the separation pad 1 as shown in FIG.
And a support portion 2b having a support shaft 2a for rotatably supporting the separation pad 1 inserted into the separation pad 1 and a spring receiving portion 2c for holding the separation pressing spring 3 together with the separation pad 1. Then, the separation pad 1 and the separation pressure spring 3 are assembled to the separation pad holding member 2 to form one unit.

Further, the separation pad holding member 2 is detachably fixed to the apparatus main body 100 by fixing means such as screws and elastic locking claws. In this embodiment, the screw 10 is used as a fixing means.

Further, in the present embodiment, the separation pad 1 is formed of a synthetic resin and the separation pad holder 1 is formed.
To c, a friction member 1a having a friction coefficient slightly smaller than that of the paper feed roller 4 is adhered. Further, the rotation fulcrum hole 1c formed in the pad main body 1b is formed as an arc of the paper feed roller 4 on the upstream side in the feeding direction from the pressure contact between the separation pad 1 (friction member 1a) and the paper feed roller 4. It is provided near the tangent L.

Accordingly, when the sheet P is separated, the sheet P
Since the frictional force between the separation pad 1 and the separation pad 1 does not work in the direction in which the separation pad 1 is rotated, generation of abnormal noise such as “squeal” can be suppressed.

Next, a method of replacing the separation pad 1 will be described.

When the separation pad 1 is to be replaced, the screw 10 is first removed after the middle plate 6 is removed from the apparatus main body 100, and then the separation pad holding member 2 is removed from the apparatus main body 100 as shown in FIG. . At this time, the separation pad 1 is detached integrally with the separation pad holding member 2 without rotating, so that the separation pad 1
Also, there is no interference with the paper feed shaft 5.

Further, although the paper feed roller 8 is in contact with the separation pad 1, the paper feed roller 8 can be removed without resistance by rotating the paper feed roller 8. Therefore, the separation pad holding member 2 can be easily removed from the apparatus main body 100.

Next, outside the main assembly 100 of the apparatus, the separation pad 1 formed integrally with the separation pad holding member 2 together with the separation pressing spring 3 is attached to the separation pad holding member 2 as shown in FIG.
Remove from Specifically, the pad main body 1b of the separation pad 1 is bent inward, or the support portion 2b of the separation pad holding member 2 is bent outward, and the support shaft 2a is moved from the rotation fulcrum hole 1c.
Take out.

Next, the rotation fulcrum hole 1 of the new separation pad 1
The separation pad 1 is rotatably attached to the separation pad holding member 2 by inserting the support shaft 2a of the separation pad holding member 2 into c. At this time, since the separation pressure spring 3 can be visually recognized, it is easy to arrange the separation pressure spring 3 in a proper position and posture.

The separation pad holding member 2
After the separation pad 1 is attached to the separation pad holding member 2
Is fixed to the apparatus main body 100 with the screw 10.

As described above, the separation pad 1 and the separation pressing spring 3 are integrally held by the separation pad holding member 2 and the separation pad 1 is detachably held, so that the paper feed roller 4
In addition, the separation pad 1 can be replaced without removing the paper feed shaft 5 from the apparatus main body 100. Further, the separation pressure spring 3 can be disposed at a regular position without worrying about deformation and the like, and the replacement of the separation pad 1 is facilitated.

Further, by forming the separation pad holding member 2 separately from the apparatus main body 100, even if the apparatus main body 100 is made of a material having a low rigidity, the separation pad holding member 2 is made of a material having a high rigidity, for example, The strength of the separation pad holding member 2 to which an external force is applied every time the separation pad is replaced can be increased.

Further, in this embodiment, the position of the rotation fulcrum hole 1c of the separation pad 1 is located upstream of the pressure contact between the separation pad 1 and the feed roller 4 in the feeding direction, and However, the position of the rotation fulcrum hole 1c (the rotation fulcrum) is not limited to this position, and may be arranged on the downstream side in the feeding direction.

[0044]

As described above, according to the present invention, the separation member and the urging means are integrally held by the holding member, and the separation member is detachably held, and the holding member is detachably attached to the apparatus main body. When replacing the separation member, remove the holding member from the apparatus main body, and then remove the separation member from the holding member, without removing the paper feed roller and the paper feed shaft from the image forming apparatus main body. Also, the separation pad can be easily replaced without causing deformation of the urging means.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sheet feeding apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a sheet feeding roller portion of the sheet feeding device.

FIG. 3 is a perspective view of a separation pad and a separation pad holding member of the sheet feeding device.

FIG. 4 is a diagram showing a state in which a separation pad holding member is removed from the sheet feeding device.

FIG. 5 is a view showing a state in which a separation pad is removed from the separation pad holding member.

FIG. 6 is a diagram illustrating a schematic configuration of a laser printer as an example of a conventional image forming apparatus.

FIG. 7 is a sectional view of a sheet feeding roller portion of a sheet feeding device in the laser printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Separation pad 2 Separation pad holding member 3 Separation pressurization spring 4 Feed roller 5 Feed shaft 6 Middle plate 8 Feed roller 10 Fixing screw 100 Main body 100A Image forming unit 100B Sheet feeding device P sheet

Claims (6)

[Claims] A sheet feeding roller that feeds a sheet; a separating member that separates the sheets fed by the sheet feeding roller one by one; and a biasing member that urges the separating member toward the sheet feeding roller. A sheet feeding device, comprising: a biasing unit; and a holding member that holds the urging unit and detachably holds the separation member, wherein the holding member is detachably attached to the apparatus main body. apparatus. 2. The sheet feeding device according to claim 1, wherein the holding member can be attached and detached without the separation member coming into contact with the sheet feeding roller. 3. The paper feed roller is a roller having a missing portion, and when the sheet supply roller is stopped with the missing portion facing the separation member, the sheet feeding roller abuts on the separation member. 2. The sheet feeding device according to claim 1, further comprising rollers. 4. The sheet feeding apparatus according to claim 1, wherein said holding member and said apparatus main body are made of different materials. 5. The sheet feeding apparatus according to claim 1, wherein the means for attaching the holding member to the apparatus main body is a screw or an elastic locking claw. 6. An image forming apparatus comprising an image forming section and a sheet feeding device, wherein the sheet feeding device is the one according to any one of claims 1 to 5. apparatus.