JP2552040B2 - Double feed prevention device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double feed prevention device for a paper feed mechanism of an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a paper feed cassette 5 for storing paper and a pickup roller 2 for feeding paper from the paper feed cassette 5 are provided in an image forming apparatus.
2, and a guide plate 23 for guiding the sheet fed by the pickup roller 22 are provided. The paper feed roller 1 is provided above the center of the guide plate 23, and the pad mounting plate 13 is provided below the center of the guide plate 23. The friction pad roller 8 mounted on the pad mounting plate 13 It is pressed by a spring 2 as an urging means so as to contact the paper feed roller 1.

Further downstream from the guide plate 23, a pair of conveying rollers 24 are provided for supplying paper to the photosensitive drum 21.
A pair of registration rollers 25 and the like are provided.

When the pickup roller 22 feeds out the paper from the paper feed cassette 5 and supplies it to the paper feed roller 1,
The friction pad roller 8 in contact with the paper feed roller 1 moves downward by the thickness of the paper against the pressing force of the spring 2 so that the paper is moved between the paper feed roller 1 and the friction pad roller 8. The paper feed roller 1 rotates in the direction of the arrow, and conveys the paper downstream. At this time, when the pickup roller 22 sends out a plurality of sheets to the feed roller 1 side, the sheets are sandwiched between the feed roller 1 and the friction pad roller 8, but only the top sheet is on the downstream side. The friction pad roller 8 prevents double feeding of the lower sheet by the frictional force and the like.

[0005]

However, in the conventional method of mounting the friction pad roller 8 as described above, the surface of the friction pad roller 8 is worn, and when the friction pad roller 8 is replaced, the spring 2 should be removed before the friction. It is necessary to replace the pad roller 8 and then attach the spring 2 again.

Therefore, the pressing force of the spring 2 may differ before and after the replacement of the friction pad roller 8.
There is a problem that a sheet feeding failure such as no sheet feeding or double feeding occurs due to a change in pressing force.

In view of the above problems of the conventional double feed prevention apparatus, the present invention provides a double feed prevention apparatus which does not cause a paper feed failure because the pressing force of the spring does not change before and after the replacement of the friction pad roller. It is intended to be provided.

[0008]

SUMMARY OF THE INVENTION The present invention provides a guide plate for guiding a sheet, a side plate having an opening downwardly connected to a downstream end of the guide plate, and a lower surface of the guide plate. The attached support member, the pad support plate rotatably connected to the support member under the guide plate, and the pad support plate detachably attached to the guide plate side for preventing double feed. Pad means and urging means provided between the other portion of the pad support plate and a portion below the opening portion of the side plate for bringing the pad of the pad means into contact with the sheet feeding roller by the urging force. It is a double feed prevention device.

[0009]

According to the present invention, when the pad means is replaced, the pad means is detached from the pad support plate and the new pad means is attached to the pad support plate by utilizing the opening provided in the side plate. At this time, since the biasing means is not removed before and after the replacement of the pad means, the biasing force does not change.

[0010]

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

FIG. 1 is a side view of a part of an image forming apparatus equipped with a double feed prevention device according to an embodiment of the present invention. That is, the image forming apparatus includes a paper feed cassette 5 for storing paper, a pickup roller 22 for feeding out paper from the paper feed cassette 5, and a guide plate 23 for guiding the paper sent by the pickup roller 22. Is provided. A paper feed roller 1 is provided above the center of the guide plate 23, and a friction pad roller 8 for preventing double feeding of paper is provided below the center of the guide plate 23 by a spring 2 serving as an urging means. It is pressed so as to be able to contact the paper feed roller 1. A side plate 10 having an opening 11 for maintenance and inspection downward is joined to the downstream end of the guide plate 23. In the opening 11,
A cover plate 17 is attached by a claw 18 (see FIG. 2) and a screw 15.

Further downstream of the guide plate 23, a pair of transport rollers 24 is provided to supply paper to the photosensitive drum 21.
A pair of registration rollers 25 and the like are provided.

The friction pad roller 8 is L
The pad means 12 is formed by being attached to the character pad attachment plate 13. The pad mounting plate 13 has a cross section U.
Fixed to the bottom plate of the V-shaped pad support plate 7 with screws 16,
The pad support plate 7 is rotatably supported by a support member 9 provided on the guide plate 23. To the lower end of the pad support plate 7, one end of a spring 2 which is an urging means for contacting the friction pad roller 8 with the paper feed roller 1 by an urging force is connected, and the other end of the spring 2 is connected. It is connected to the lower end of the side plate 10.

Next, the operation of the above embodiment will be described.

When the friction pad roller 8 is worn due to long-term use, it needs to be replaced with a new one. At this time, first, the power source of the image forming apparatus is opened and the side door 31 of FIG. 1 is opened.

When the side door 31 is opened, as shown in FIG.
There is a lid plate 17 that closes the opening 11 of the side plate 10. Therefore, the screws 1 on both sides to which the lid plate 17 is attached
Loosen 5 and remove. When the screws 15 are removed, the lid plate 17 is slightly lifted as shown in FIG. 3, and the claw 18 hooked on the lower edge of the opening 11 is pulled out to remove the lid plate 17. When the lid plate 17 is removed, the opening 11 is opened and the friction pad roller 8 and the pad support plate 7 and the like in the back are exposed.

Next, when the screw 16 is loosened with a driver while supporting the friction pad roller 8 by hand from the opening 11, the pad mounting plate 13 and the friction pad roller 8 are removed from the pad supporting plate 7 as shown in FIG. Remove and pull them out of opening 11. Then, the friction pad roller 8 attached to the new pad attachment plate 13 is inserted through the opening 11 and fastened with the screw 16 to the pad support plate 7 and fixed as before. In order to return the cover plate 17 to the original position, the lower claw 18 of the cover plate 17 is hooked and attached to the lower edge of the opening 11, and the upper side is fixed with the screw 15. As described above, since it is not necessary to remove the spring 2 when replacing the friction pad roller, the pressing force of the spring 2 does not change.

FIG. 5 and FIG. 6 show a double feed prevention device of another embodiment.

In FIG. 5, the side plate 10 is provided with the opening 11 as in the above embodiment. The friction pad roller 8 is detachable so that the shaft 8
1 is a pad mounting plate 1 having a U-shaped recess 131
3 is fitted in the recess 131. The pad mounting plate 13 is fixed to the pad support plate 7.

When replacing the worn friction pad roller 8, the side cover 31 is opened in the same manner as described above.
Remove the lid plate 17 from the side plate 10, open the opening 11,
The lower side of the pad support plate 7 is pushed inward from the opening 11 to rotate the pad support plate 7, and the friction pad roller 8
Is separated from the paper feed roller 1, and then the friction pad roller shaft 81 is pulled out from the recess 131 toward the front while shifting upward (see FIG. 6). Then, while pushing the lower side of the pad support plate 7 inward, a new friction pad roller 8
When the shaft 81 is fitted into the recess 131 and the pushing is stopped, the spring 2 returns to the original position, and the friction pad roller 8 contacts the sheet feeding roller 1.

Although the screw is used to fix the pad mounting plate in the above-mentioned embodiment, a one-touch type structure such as a hooking claw or a pressing metal fitting may be used as long as it can be securely fixed.

[0022]

As is apparent from the above description, the present invention has an advantage that the pressing force of the spring does not change before and after the replacement of the friction pad roller, so that a paper feeding failure does not occur.

[Brief description of drawings]

FIG. 1 is a side view of a part of an image forming apparatus including a double feed prevention device according to an exemplary embodiment of the present invention.

FIG. 2 is a side view explaining the operation of the embodiment.

FIG. 3 is a side view illustrating the operation of the embodiment.

FIG. 4 is a side view explaining the operation of the embodiment.

FIG. 5 is a side view for explaining the operation of another embodiment.

6 is a side view for explaining the operation of the embodiment of FIG.

FIG. 7 is a side view of a part of an image forming apparatus including a conventional double feed prevention device.

[Explanation of symbols]

 1 Paper Feed Roller 2 Spring 7 Pad Support Plate 8 Friction Pad Roller 9 Support Member 10 Side Plate 11 Opening 12 Pad Means 13 Pad Mounting Plate 23 Guide Plate

Claims (2)

(57) [Claims] 1. A guide plate for guiding a sheet, a side plate having an opening downwardly connected to a downstream end of the guide plate, and a support member attached to a lower surface of the guide plate. A pad support plate that is rotatably connected to the support member below the guide plate; and a padding member that is detachably attached to the guide plate side of the pad support plate for preventing double feed. And a biasing unit provided between the other portion of the pad support plate and a portion of the side plate below the opening for bringing the pad of the pad unit into contact with the sheet feeding roller by a biasing force. A double-feeding prevention device characterized in that 2. The pad means, the pad mounting plate, the pad is fixed to the pad mounting plate,
The double feed prevention device according to claim 1, wherein the pad mounting plate is detachably attached to the pad supporting plate.