JPH11222329A - Sheet stacking device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a control means from being adversely affected by the discharge of charge generated by friction between a sheet and a paper feeding means or another sheet and charged to a sheet stacking member in case of feeding one sheet out of a plurality of sheets stacked on the sheet stacking member, by the sheet feeding means. SOLUTION: This sheet stacking device is provided with a container part 3b that can store a plurality of sheets, a stacking member 3a for stacking the sheets in the container part 3b, and an energizing means 3c for energizing the stacking member 3a in the container part 3b in order to bring the sheets into contact with a feeding means. A part of the energizing means 3c is extended to the outer surface of the container part 3b so as to make charge charged to the stacking member 3a, escape through the extended part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet stacking apparatus for stacking a plurality of sheets for forming an image and attaching the stacked sheets to a sheet feeder so that the stacked sheets can be fed. The present invention relates to an image forming apparatus in which a sheet stacking device is detachable and forms an image on a sheet fed from the sheet stacking device.

[0002]

2. Description of the Related Art Conventionally, a sheet cassette as a sheet stacking device for stacking sheets is detachably mounted on an image forming apparatus main body.

FIG. 5 schematically shows an electrophotographic copying machine 1 as an example of an image forming apparatus using such a paper feed cassette. A copying machine 1 shown in FIG. 1 has an image forming apparatus main body having an image forming unit (hereinafter, simply referred to as “apparatus main body”).
2 is provided. A paper feed cassette 3 as sheet stacking means for stacking transfer sheets S such as paper is mounted at the lower portion of the apparatus main body.

The paper feed cassette 3 has a box-shaped cassette tray 3b as a container part capable of storing a plurality of sheets.
An intermediate plate 3a as a loading member for loading sheets S therein.
The middle plate is pivotally supported at its rear portion by a side plate or the like of the tray so as to be swingable, that is, is movable in a direction close to and away from the bottom plate of the tray. The distal end (the right side in the figure) of the middle plate 3a is urged in the direction of the feeding means described later by a compression spring 3c as the urging means. A rear end regulating member 3d for regulating the rear end of the transfer sheet is mounted on the cassette tray 3b.

The apparatus main body 2 of the image forming apparatus 1 includes a half-moon-shaped feeding roller 6 and a feeding roller 6a coaxially with the feeding roller 6, and the feeding roller 6a is an intermediate plate during standby. The uppermost transfer sheet S of the transfer sheet 3a is in contact with the uppermost transfer sheet S, and the feeding roller 6 is in contact with the uppermost transfer sheet S of the transfer sheet S on the middle plate 3a during paper feeding. Downstream of the transfer sheet S in the sheet feeding direction, a separation pad 4 for separating the transfer sheet S is urged by a compression spring 3h and mounted on the cassette tray 3b. It is designed to be fed. Furthermore,
A transfer roller 7 and a registration roller 9 are provided downstream of the transfer sheet S being fed.

A scanner 10 that emits a laser beam L and a mirror 11 that reflects a laser are disposed above the apparatus main body 2. And in the approximate center of the device main body 2,
The image forming unit 5, that is, a photosensitive drum 5 a on which a latent image is written by an electrophotographic method in response to the irradiation of the laser beam L reflected by the mirror 11 and a toner image formed by attaching toner to the latent image and developing it And a transfer means 5c for contacting the photosensitive drum 5a to transfer the toner image formed on the image drum 5a to the transferred transfer sheet S.

[0007] A fixing device 12 for fixing a toner image on the transfer sheet S is provided downstream of the photosensitive drum 5a, and a pair of transport rollers 13, 15 and a transport roller 16 are further downstream. The upper portion of the apparatus main body 2 is provided with a paper discharge tray 17 on which the transfer sheet S is placed. on the other hand,
A manual insertion port 18 is provided on the right side of the apparatus main body in the figure, and is configured so that the transfer sheet material S is transported to the image forming unit 5 through a transport roller pair 19.

FIG. 6 shows a detailed view of separation of the transfer sheet under such a configuration. As shown in this figure, the transfer sheet S placed on the middle plate 3a of the sheet feeding cassette 3
When the feed roller 6 rotates in the direction of arrow R, the transfer sheet S is fed onto the separation pad 4 on the downstream side of the transfer sheet S. At this time, the friction coefficient between the uppermost transfer sheet S and the second transfer sheet on the rubber portion 4b of the separation pad 4 and on the middle plate 3a is μ1, and the rubber portion of the second transfer sheet and the separation pad 4 is The coefficient of friction with 4b is μ2
When the pressing force of the middle plate compression spring 3c is P and the pressing force of the separation pad compression spring 3h is F, μ1 P + μ1 F <μ2 F
, Only the uppermost transfer sheet can be fed without double feeding.

The paper feed cassette is provided in the main body of the apparatus.
As shown in (1), the engaging portion 3e of the cassette is engaged with and biased by the cassette holding plate spring 8 provided on the apparatus main body side, and is detachably fixed to the sheet feeding position. The cassette holding plate spring 8 urges the sheet feeding cassette 3 so that it does not move from the feeding position by the sheet feeding operation, and the operator uses the fixing force of the cassette holding plate spring 8 when replenishing the sheet feeding cassette 3 with paper. The load is set so that the sheet cassette 3 can be taken out of the apparatus main body 2.

[0010]

However, when the above-described separation method is used, the uppermost transfer sheet S and the second transfer sheet on the rubber portion 4b of the separation pad 4 and the middle plate 3a are not separated. Electric charge is generated by friction, which is the middle plate 3a
Is accumulated in Therefore, when the electric charge is discharged, a malfunction of the control circuit may be caused, or when the user's finger touches the middle plate at the time of replenishment of the transfer sheet or the like, discomfort may be caused by a discharge shock.

Accordingly, the present invention provides a seat which enables the electric charge accumulated in the above-mentioned middle plate to be dropped into the main body device and prevents the malfunction of the control circuit and the electric shock of the user due to the discharge of the electric charge. An object of the present invention is to provide a loading device and an image forming device.

[0012]

In order to achieve the above object, a means according to the present invention comprises a container portion capable of storing a plurality of sheets, a stacking member for stacking the sheets in the container portion, and a sheet member. Urging means for urging the loading member in the container portion, in order to contact the feeding means,
A part of the urging means is extended to the outer surface of the container part, and the charge charged to the loading member is released by the extended part.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, the image forming apparatus main body shown in FIG. 5 and conventionally known ones are used, and members having the same configuration and operation as those of the conventional art are denoted by the same reference numerals and description thereof is omitted. I do.

(First Embodiment) FIG. 1 is a top view of the apparatus main body 2 when a paper feed cassette 3 is mounted thereon, which best illustrates the features of the present invention. As shown in FIG.
A compression spring 3c as a conductive urging means for urging the middle plate 3a is disposed below the a. The compression spring is
In the present embodiment, a coil spring is used, and one end of the coil spring extends along the wall surface of the sheet cassette 3 to the outer surface of the side of the sheet cassette 3. The extension end of the compression spring is preferably bent in a V-shape or U-shape and locked by a locking portion 3 f on the side surface of the sheet cassette 3.

The apparatus main body 2 is provided with a cassette holding member 8 such as a leaf spring. The holding member is formed of a leaf spring, which is a conductive elastic member, and is configured to hold a paper feed driving gear and the like. It is attached to the paper drive system side plate 38. When the paper feed cassette is inserted into the apparatus main body 2, the conductive cassette holding plate spring 8 attached to the paper feed drive side plate 38 comes into contact with a portion of the compression spring 3c which is extended on the side surface of the paper feed cassette 3. , The electric charge charged on the middle plate 3a is converted into a compression spring 3c,
It can be dropped onto the paper feed drive system side plate 38 of the apparatus main body via the cassette holding spring 8. Electric charges from the apparatus main body are appropriately dropped to a ground line. FIG. 2 shows a perspective view composed of only components that pass through the electric charge.

As described above, according to this embodiment, the electric charge to be charged on the middle plate is extended only by extending the compression spring for urging the middle plate, which is originally used, without increasing the number of parts. It is possible to prevent malfunction of the control means due to the discharge of the charge on the intermediate plate and discharge shock to the user.

(Second Embodiment) FIG. 3 is a view showing a second embodiment according to the present invention.
It is a top view when mounting | wearing. As shown in FIG.
A conductive compression spring 3c for urging the middle plate 3a is disposed below the middle plate 3a, and one end of the compression spring 3c extends along the wall surface of the sheet cassette 3 to the side surface of the sheet cassette 3. You. As shown in FIG. 3, one end of the extension of the compression spring 3c is a linear spring, and has a spring force equivalent to that of the cassette holding spring 8. The end of the compression spring 3c is bent into a V-shape or a U-shape, and the front end is locked by a locking portion 3f on the side of the sheet cassette. Further, by holding the compression spring 3c closer to the main body than the V-shape by the holding portion of the sheet cassette, for example, the holding portion 3g on the side surface of the cassette, a spring force equivalent to that of the conventional cassette holding spring is exerted. When the paper feed cassette 3 is inserted into the apparatus main body 2, it comes into contact with the cut-and-raised portion 38 a of the paper feed drive system side plate 38, and the electric charge of the middle plate 3 a can be dropped on the paper feed drive system side plate 38. The sheet feeding cassette serves as the holding spring 8 and is moved to the apparatus main body to prevent the sheet cassette from slipping out. FIG. 4 shows a perspective view composed of only components that pass through the electric charge.

As a result, in the present embodiment, the cassette holding spring 8 becomes unnecessary, and the problem can be solved with a smaller number of parts than in the first embodiment.

[0019]

As described above, according to the present invention,
The electric charge accumulated in the sheet stacking member is released to the outside without increasing the number of parts, thereby preventing a malfunction of the control circuit and performing good printing. It is also possible to prevent a user from feeling uncomfortable when replenishing a sheet or the like.

[Brief description of the drawings]

FIG. 1 is a plan view of a sheet feeding cassette according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the paper feed cassette according to the first embodiment of the present invention.

FIG. 3 is a plan view of a paper feed cassette according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a main part of a paper feed cassette according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing the whole of a conventional image forming apparatus.

FIG. 6 is a cross-sectional view showing a state of conventional feeding.

FIG. 7 is a plan view of a paper feed cassette fixed to a conventional apparatus main body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus (copier) 2 ... Image forming apparatus main body 3 ... Paper feed cassette 3a ... Middle plate 3b ... Cassette tray 3c ... Middle plate compression spring 3d ... Transfer sheet rear end regulating member 3f ... Locking part 3g ... Holding Part 3h Separating pad compression spring 4 Separating pad 4a Separating pad resin part 4d Separating pad rubber part 6 Feed roller 6a Feed roller 8 Cassette holding plate spring 34 Paper size detection cam 35 Paper size detection cassette Holding plate spring 8 36: paper size detection arm 37: paper size detection sensor (switch) 38: paper feed drive system side plate

Claims (6)

[Claims] 1. A container part capable of storing a plurality of sheets,
A loading member for loading the sheet in the container portion; and a biasing device for biasing the loading member in the container portion to contact the sheet with a feeding device, a part of the biasing device. A sheet stacking device, wherein the sheet is extended to an outer surface of the container portion, and the charge charged to the stacking member is released by the extension portion. 2. A container portion capable of storing a plurality of sheets,
A stacking member movably provided in the container portion for stacking sheets, and a conductive elastic member for urging the stacking member to contact the sheet on the stacking member with a feeding unit; A sheet stacking device, wherein one end of the sheet stacking unit is extended to an outer surface of the container unit to form a charge removing unit for releasing charges charged on the stacking member. 3. The sheet stacking apparatus according to claim 2, wherein the elastic member is formed of a coil member, and one end of the elastic member is extended to an outer surface of a side of the container. 4. A sheet stacking device according to claim 1, holding means for detachably holding said sheet stacking device, and image forming for forming an image on a sheet fed from said sheet stacking device. An apparatus main body provided with means, and in a state where the sheet stacking apparatus is mounted on the apparatus main body, the stacking member is provided from the urging means of the sheet stacking apparatus or an extension of an elastic member via the holding means. An image forming apparatus characterized in that the charged electric charges are caused to flow through the apparatus main body. 5. An image forming apparatus according to claim 4, wherein said holding means is constituted by an elastic member provided on the apparatus main body, and holds the side surface of said container portion. 6. The sheet according to claim 4, wherein the holding means is formed of a rigid member provided on the apparatus main body, and an extended end of the elastic member elastically engages with the holding means. An image forming apparatus, wherein a loading device is held in a mounted state with respect to the device main body.