JPH0682256B2 - Copier transfer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device of a copying machine, which allows a transfer unit to be inserted and removed without damaging a photoreceptor.

2. Description of the Related Art A conventional electrophotographic copying machine is provided with a transfer device for transferring a toner image formed on the surface of a photoconductor by a developing process onto a sheet.

The transfer device is provided with a transfer guide member for bringing the paper fed from the paper feeding device into close contact with the photoconductor, and the transfer guide member has a transfer defect such as partial omission during transfer. In order to prevent the above, it is necessary to mount it at a position closer to the photoconductor.

Further, the transfer guide member is generally mounted on the transfer unit side that can be freely inserted into and removed from the main body of the copying machine so that the jammed paper can be easily removed when a paper jam occurs.

FIG. 10 shows an example of a conventional transfer guide member. A transfer guide member b is provided in the vicinity of the belt-shaped photoconductor a, and the central portion of the transfer guide member b is pressed by a pressing roller c. By pressing both end sides against the positioning block d, the positioning is performed at a position close to the photoconductor a.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-mentioned conventional transfer device, the transfer guide member b is attached to the photosensitive member a.
When the transfer unit is brought close to the contact member, the transfer guide member b may damage the photosensitive member a when the transfer unit is pulled out, so that it cannot be provided close to the photosensitive member a. Transfer failure is likely to occur, and since the transfer guide member b is pressed against the positioning block d by pressing a portion other than the positioning block d, if the pressing force is too strong, the transfer guide member b will warp and the pressing force will increase. If it is weak, the pressing force against the positioning block d becomes insufficient, and it is difficult to adjust the pressing force.

The present invention has been made for the purpose of improving the above problems.

Means and Actions for Solving Problems In order to achieve the above-mentioned object, the present invention has a transfer unit that can be freely inserted into and removed from the copying machine main body, and a transfer device and a sheet to be transferred to this transfer unit. In a copying machine provided with a transfer guide member for guiding the sheet to the photosensitive member, when the transfer unit is mounted on the copying machine main body at the mounting completion position of the copying machine main body, the transfer guide member abuts on the transfer guide member. A positioning block for positioning the transfer guide member with respect to the photoconductor is provided, and a biasing means for biasing the transfer guide member in the direction of separating from the photoconductor on the transfer unit side, and the transfer unit with the copying machine main body. The transfer guide member presses the position where the transfer guide member comes into contact with the positioning block from the rear when it is inserted to the mounting completion position, and releases the press when the transfer unit starts to be pulled out. It is equipped with a depressing means.
Since it is automatically separated from the transfer guide member by the biasing means, there is no need to damage the surface of the photoconductor.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view of a copying machine using a belt-shaped photoconductor, which has a document table 2 on which an original document (not shown) to be copied is placed on an upper part of the copying machine body 1. The image of the document placed on the document table 2 is imaged on the photoconductor 4 by the optical system 3 to form an electrostatic latent image on the photoconductor 4. The electrostatic latent image is developed into a toner image by the developing device 5, reaches the transfer device 6, and is transferred onto the paper 8 fed from the paper feeding device 7.

The transfer device 6 and the peeling device 9 provided in the vicinity of the transfer device 6 are installed together with the transfer guide member 10 and the like on the transfer unit 11 side that can be inserted into and removed from the copying machine main body 1 toward the front side.

As shown in FIG. 3, the transfer unit 11 is provided with guide rails 12 for moving on guide rollers (not shown) provided on the copying machine main body 1 side on both sides of the lower part, and when mounted in the copying machine main body 1. The transfer device 6 is provided at a position close to the photoconductor 4.
Also, the peeling device 9 is attached separately in the vertical direction.

A transfer guide member 10 is provided below the transfer device 6. The transfer guide member 10 has a plate shape elongated in the lateral direction, and a bracket 13 fixed to the lower portions of both ends is provided with a shaft 14.
Is supported by the upper edge side so as to be rotatable around the shaft 14 in the contacting / separating direction of the photoconductor 4 and the tension spring 15
Is urged in the separating direction of the photoconductor 4.

On the other hand, on the upper end side of the transfer guide member 10, a pair of positioning pins 16 are provided on the side surface of the photosensitive member 1, and on the opposite surface, a pair of cams 17 are laterally spaced apart from each other.

These positioning pins 16 and cams 17 serve to position the transfer guide member 10 when the transfer unit 11 is mounted on the copying machine main body 1, and an axial rod 18 is provided behind each cam 17. The shaft rod 18 is movably supported in the horizontal direction between the frames 11a of the transfer unit 11, and a compression spring 19 is provided on one end side thereof. The action of the spring 19 will be described later.

Further, one end side of a leaf spring 20 is attached to the shaft rod 18 at substantially equal intervals with the cam 17, and the cam spring 17 is attached by these leaf springs 20.
The transfer guide member 10 is pushed into the photosensitive member 4 side via the.

On the other hand, a paper guide 21 is installed at a position facing the upper end side of the transfer guide member 10. As shown in FIGS. 7 and 8, a positioning block 22 is fixed to the sheet guide 21 at a position facing the transfer guide member 10 at substantially equal intervals with a positioning pin 16 protruding from the transfer guide member 10. There is.

These positioning blocks 22 have a function of guiding the paper to the side of the photoconductor 4 with the transfer guide member 10 and a function of positioning the transfer guide member 10, and are provided on the surface facing the transfer guide member 10. A guide groove 22a is provided in the horizontal direction. Both end sides of these guide grooves 22a are wide so that the tips of the positioning pins 16 can easily enter the guide grooves 22a.

Reference numeral 23 in the figure denotes a paper feed roller.

Next, the operation will be described with reference to FIGS. 9 (a) and 9 (b).
At the time of copying, the transfer guide member 10 guides the paper 8 sent from the paper feeding device 7 via the paper feed roller 23 at the position shown in FIG. When the transfer unit 11 is pulled out from the copying machine main body 1 due to paper jam during copying, etc.,
It is retracted in the direction away from the photoconductor 4 as follows.

That is, when the transfer unit 11 is pulled out from the copying machine main body 1,
The transfer guide member 10 provided on the transfer unit 11 side also moves together with the transfer unit 11 in the direction of arrow A in FIG.

At this time, since the shaft rod 18 supported on the transfer unit 11 side is pressed against the frame 1a of the copying machine main body 1 by the action of the compression spring 19, the position does not change, and accordingly, the transfer guide member 10 is moved in the direction of arrow A. With the movement, the cam 17 is disengaged from the leaf spring 20 and released from the leaf spring 20, so that the upper end side of the transfer guide member 10 is rotated by the action of the tension spring 15 in the direction away from the photoconductor 4, and the photoconductor 4 is moved. Since the transfer guide member 10 is retracted, even if the transfer unit 11 is pulled out, the transfer guide member 10 does not damage the photoconductor 4.

When the transfer unit 11 is pushed again into the copying machine main body 1 after the jammed paper 8 is removed, one end of the shaft rod 18 first comes into contact with the frame 1a as shown in FIG. 9 (b) and stops at that position. To do.

When the transfer unit 11 is further pushed in the direction of arrow B from this state, the cam 17 protruding from the transfer guide member 10 causes the leaf spring to move.
20. The upper end of the transfer guide member 10 is rotated by the leaf spring 20 toward the photoconductor 4 by the leaf spring 20, and at the same time, the positioning pin 16 projecting toward the paper guide 21 is placed in the guide groove 22a of the positioning block 22. Enter.

When the transfer unit 11 is pushed all the way into the main body 1 of the copying machine, the transfer guide member 10 moves the leaf spring 20 and the positioning block 22.
As shown in FIG. 9 (a), the photoconductor 4 is inserted between
It will be positioned and fixed at a position close to the surface of the.

Further, by positioning the transfer guide member 10 as described above, the gap d between the photosensitive member 4 and the transfer guide member 10 is set to 0 <
It becomes possible to set in the range of d <0.8 mm.

Although the copying machine using the belt-shaped photoconductor 4 is described in the above embodiment, the present invention can be applied to the copying machine using the drum-shaped photoconductor.

As described above in detail, according to the present invention, when the transfer unit is pulled out from the main body of the copying machine due to a paper jam or the like, the transfer guide member provided close to the photoconductor is automatically separated from the photoconductor. Since it is retracted to, there is no risk of damaging the photoconductor by the transfer guide member.

Also, since the vicinity of the rear side of the portion where the transfer guide member abuts on the positioning block is pressed, the transfer guide member is not deformed by the pressing force, and thus the strong pressing force is not impaired in the guide function of the paper. The transfer guide member can be reliably pressed against the positioning block and the transfer guide member can be positioned close to the surface of the photoconductor, so that the occurrence of transfer defects can be reduced.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is an overall schematic configuration diagram, FIG. 2 is an enlarged sectional view of this apparatus, FIG. 3 is a side view of a transfer unit, and FIG. FIG. 5 is a side view of the transfer unit with the transfer guide member and the like removed, FIG. 5 is a view in the direction of arrow V in FIG. 4, FIG. 6 is a rear view of the transfer guide member, and FIG. FIG. 8 is a sectional view of the same, FIGS. 9 (a) and 9 (b) are explanatory views of operation, and FIG. 10 is a conventional explanatory view. 1 is a copying machine main body, 4 is a photoconductor, 6 is a transfer device, 10 is a transfer guide member, 11 is a transfer unit, and 22 is a positioning block.

Claims (1)

[Claims] 1. A transfer unit 11 which can be inserted into and taken out of a main body 1 of a copying machine, and the transfer unit 6 is attached to the transfer unit 11.
In a copying machine provided with a transfer guide member 10 that guides the sheet 8 to be transferred to the photoconductor 4, the transfer unit 11 is moved to the mounting completion position of the copying machine body 1 on the copying machine body 1 side. When mounted, a positioning block 22 is provided that contacts the transfer guide member 10 to position the transfer guide member 10 with respect to the photoconductor 4, and the transfer guide member 10 is provided on the transfer unit 11 side. 4, when the transfer unit 11 is inserted up to the mounting completion position of the copying machine main body 1 and the biasing means for biasing the transfer unit 11 away from the position 4, the position where the transfer guide member 10 contacts the positioning block 22 is pressed from the rear side,
Further, the transfer device of the copying machine is provided with a transfer guide pressing means for releasing the pressing when the transfer unit 11 is started to be pulled out.