JPH0133548Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a friction separation roller paper feeding type paper feeding device used in copying machines and the like.

Conventional technology A paper feeding device for a copying machine, etc. consists of a feed roller that rotates in the paper feeding direction, and a reverse roller that presses against the feed roller across the paper path and applies a constant torque in the opposite direction to the paper feeding direction by a torque limiter. When there is no paper between the two rollers or when only one sheet of paper is sent, the torque due to the frictional force between the rollers or between the paper and the rollers overcomes the above torque and the reverse roller is activated. follows the feed roller and rotates in the paper feeding direction without slipping with the feed roller or the paper, and simultaneously rotates the paper.
When more than one sheet of paper is fed between the two rollers, the torque applied from the torque limiter to the reverse roller overcomes the frictional force between the sheets, and the second and subsequent sheets are transferred to the paper feed tray. There is known a friction separation roller paper feeding system in which the paper is pushed back toward the feed roller to separate the paper, and only the one sheet in contact with the feed roller is fed to the apparatus.

In this type of paper feeding device, the reverse roller is less likely to slip with the feed roller and the paper, compared to a separate paper feeding device in which the reverse roller always rotates in the opposite direction to the paper feeding direction or is always stationary. It is superior in that it reduces paper fuzz, paper dust generation, and roller friction due to friction.

In the above-mentioned friction separation roller paper feeding system, double fed sheets are separated based on the difference between the friction between the roller and the paper and the friction between the sheets, so the smaller the conveyance resistance at the separating section, the better the separation. Performance is improved. on the other hand,
The position and diameter of the reverse roller and the position of the drive gear are also factors that determine the separation performance.If you want to improve the separation performance, the drive gear of the reverse roller is installed on an axis parallel to the axis of the reverse roller, and the axis is If the structure is such that the reverse roller is supported by an arm that swings at the center and the reverse roller is brought into pressure contact with the feed roller, the upper end of the outer periphery of the drive gear will inevitably come close to the nip line between the feed roller and the reverse roller. Therefore, if the cover that covers the reverse roller drive section is placed away from the drive gear so that it does not come into contact with the drive gear, the top surface of the cover may come too close to the nip line between the feed roller and reverse roller. If you cannot create a sufficient gap and the thickness becomes equal to or less than the thickness of the stack of paper that is being fed double, there will be a large resistance to the reverse roller transporting the paper in the return direction, and the lower side will It is not possible to return the paper, which may result in double feeding or a paper jam.

Purpose This invention solves the above-mentioned problems of the friction separation roller paper feeding system.The position and diameter of the reverse roller and the position of the drive gear are maintained at the positions necessary for separation performance, while the upper surface of the drive unit cover and the feed roller are kept close to each other. It is an object of the present invention to provide a paper feeding device using a friction separation roller paper feeding method that can secure a necessary separation and conveyance gap between the paper feed device and the paper feed device.

Configuration The present invention will be described in detail below based on embodiments shown in the drawings.

In the embodiment of the present invention shown in FIGS. 1 and 2, the reverse roller 2 that presses against the feed roller 1 across the paper path has a shaft 3 of the reverse roller.
By driving the driven gear 4 provided on the shaft 3 by the drive gear 6 provided on the drive shaft 5 provided parallel to the shaft 3, a torque limiter (not shown) provided on the shaft 3 causes a predetermined speed in the reverse paper feeding direction. The fact that torque is applied is the same as before.

In the apparatus of this embodiment, a guide roller 7 is further provided adjacent to and coaxially with the drive gear 6. The diameter of the guide roller 7 is made slightly larger than the diameter of the drive gear 6. Guide roller 7
may be rotatably supported on the shaft 5 or may be fixed to the shaft 5. drive gear 6,
A removable cover 8 is provided that covers the guide roller 7, the driven gear 4, a torque limiter (not shown), and a reverse roller. The cover 8 prevents paper dust and the like from adhering to the torque limiter, gears, etc. and deteriorating performance, and also serves as a paper guide. The cover 8 is provided with a notch 8a through which the upper end of the reverse roller 2 protrudes. A mounting hole 8b is formed in the hanging part of the rear end of the cover 8 (the side facing the paper feed cassette), and by loosely fitting a screw 9 through this hole, the rear part of the cover 8 is attached to a fixed guide plate (not shown). loosely attached to the A protrusion 8c with a flat surface on the upper part is formed by drawing at a portion corresponding to the drive gear 6 and guide roller 7 near the front end of the horizontal part of the cover 8, and the lower surface of the flat surface is placed on the guide roller 7. The cover 8 is supported by being placed thereon.

Since this device is constructed as described above, the cover 8 is supported by the guide roller 7 having an outer diameter slightly larger than the outer diameter of the drive gear 6, and a small gap is stably maintained between the cover 8 and the drive gear 6. Therefore, the gap between the upper surface of the protrusion 8c and the nip line between the feed roller 1 and the reverse roller 2 can be made as large as possible. Therefore, there is less possibility that the double-fed sheets will create resistance when they are returned by the reverse roller 2, and the separation performance is greatly improved. Moreover, the shape of the cover becomes simple and the ease of assembly is improved.

Effects As described above, the present invention is effective in improving the separation performance of double-fed sheets and improving the ease of assembling the reverse roller drive unit cover.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing an embodiment of the present invention;
The figure is an exploded perspective view. DESCRIPTION OF SYMBOLS 1... Feed roller, 2... Reverse roller, 3... Reverse roller shaft, 4... Driven gear, 5... Drive shaft, 6... Drive gear, 7... Guide roller, 8... Drive section cover.

Claims (1)

[Scope of utility model registration request] A roller pair consisting of a feed roller that rotates in the paper feeding direction and a reverse roller that presses against the feed roller across the paper path and applies a constant torque in the opposite direction to the paper feeding direction, and an axis that is parallel to the axis of the reverse roller. In the friction roller separation sheet feeding device, the friction roller separation sheet feeding device has the reverse roller drive gear, which is provided at A guide roller having an outer diameter slightly larger than the outer diameter of the drive gear is provided coaxially with and adjacent to the reverse roller drive gear, and the drive section cover is placed and held on the guide roller. . A paper feeding device characterized in that a required paper separation and conveyance gap is provided between the upper surface of the cover and the circumferential surface of the feed roller.