JPH0460901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a friction roller separation and feeding device that separates and feeds sheets stacked on a sheet feed tray of a copying machine, etc. one by one.

In a copying machine, a facsimile machine, etc., a device that feeds stacked sheets one by one is, for example, a movable bottom plate 2 on a paper feed cassette 1, as shown in FIG.
A pick-up roller 4 that presses against the upper surface of the paper stack 3 stacked on top and rotates in response to a paper feed signal to feed out the topmost paper, and a feed roller that is located downstream of the roller in the paper feed direction and rotates in the paper feed direction. 5, and a separation roller 6 which presses against the feed roller 5 across the paper path and rotates or remains stationary in a direction to push back the paper. By selecting the material of each roller so that the relationship between the coefficients of friction μf, μs, and μp between the sheets and between sheets is μf>μs>μp, it is possible to reduce the number of sheets that are fed double due to the difference in friction coefficients. Friction roller separation and feeding devices that separate and feed sheets one by one are widely used. In this case, the separation roller 6 is pressed against the feed roller 5 by a pressure spring 9 via a pressure lever 8 that swings around a shaft 7 that is pivotally supported on the machine frame, and is connected to a drive gear fixed to the shaft 7. 10 and a driven gear 11 integrally provided on the shaft of the separation roller 6.
are rotated by meshing with each other.

However, with this method, the pick-up roller 4
When only one sheet is fed, or when multiple sheets of paper are separated and only one sheet is fed, the separation roller 6 rotating in the return direction and the paper will rub, and depending on the paper quality, the paper may Problems such as undulating paper, fluffing of the paper surface, and generation of paper dust may occur, and paper fibers may adhere to the separation roller 6 over time, reducing the coefficient of friction and making the separation effect uncertain. It was hot.

As a paper feeding device that improves this, a constant torque is applied to the separation roller 6 in the direction of pushing back the paper through a torque limiter, and the paper is pushed back once.
When only one sheet of paper is fed, or when one separated sheet of paper is fed, the frictional force between the separation roller 6 and the paper overcomes the above torque, causing the separation roller to slip against the paper. If two or more sheets of paper are fed simultaneously, the frictional force between the sheets is smaller than the above torque, so the separation roller 6 rotates in the direction of pushing the sheets back. A method has been proposed in which all but the topmost sheet are pushed back and separated.

However, in the conventional friction separation paper feeding device of this type, the separation roller 6 is located at the back of the paper guide plate 12 as shown in FIG. The torque limiter is supported through a provided hole, and the torque limiter is provided on the shaft 7 that supports the pressure lever 8, making serviceability during maintenance extremely difficult.

An object of the present invention is to provide a paper feeding device that eliminates the above-mentioned drawbacks of the conventional friction separation paper feeding device having a torque limiter and improves serviceability during maintenance of the paper feeding section roller, particularly the separation roller and the torque limiter section. purpose.

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments thereof.

In the embodiment shown in FIGS. 2 to 5, the separation roller 6, torque limiter 13, and driven gear 11 are coaxially provided on one shaft 14 to constitute a separation roller unit. The separation roller 6 is constructed by wrapping a rubber ring 16 around the enlarged part of a metal hub 15 which is rotatable about the shaft 14, and the driven gear 11 is formed by the aforementioned hub which is also rotatable about the shaft 14. It is formed on the outer periphery of the other end of another metal hub 17 whose end surfaces are in contact with 15. The torque limiter 13 is formed by a coil spring 18 wound tightly with a certain pressure across two hubs 15 and 17 whose end surfaces are in contact with each other.
If a torque greater than the smaller of the torque due to the frictional force with 7 is applied to the separation roller, it will slip between the spring 18 and the circumferential surface of the hub 15 or 17, and the separation roller 6 will become a gear. 11, but is driven by the feed roller 5 and rotates.

Both ends of the shaft 14 are inserted into guide grooves 20 that are open on the side facing away from the feed roller 5, which is provided in a bracket 19 fixed to the machine frame, and are rotatable around the shaft 7 provided in the bracket 19. The separation roller 6 is urged toward the feed roller 5 by a pressure spring 22 via a pressure arm 21 provided therein.
is pressurized at a predetermined pressure.

As shown in FIG. 3, the lower guide 12 has a cut of the size necessary to insert and remove the separation roller unit into and out of the lower guide 12 and to fit and remove the shaft end into the guide groove 20 of the bracket 19. A roller cover 2 is provided with an opening 12a and a notch 23a that normally exposes only the vicinity of the portion of the separation roller 6 that is in contact with the feed roller 5.
Covered by 3. With the separation roller unit installed, the gear 11 meshes with the drive gear 24 pivotally supported by the bracket 19.
The shaft 14 is driven.

Since each sheet feeding position is configured as described above, there is a separation roller 6 and a torque limiter 13.
When performing maintenance and inspection, move the roller cover 23 to the lower guide 1.
When removed from 2, the entire separation roller unit will be exposed. Therefore, when the ear 21a protruding from one end of the pressure arm 21 is pushed down, the separation roller unit is caused by its own weight to cause both ends of the shaft 14 to move inside the guide groove 20 of the bracket 19 as shown in chain lines in FIG. It will fall to the position shown in and can be easily taken out.

When installing the separation roller unit, place its shaft end on the ends of one side of the pressure arm 21, and insert it into the guide groove 20 of the bracket 19.
If you release your hand from the ear part 21a while placing your hand on the guide surface continuous with the guide surface, both ends of the shaft 14 of the separation unit will fit into the guide groove 20, and the pressure spring 2
2, the separation roller 6 is pressed against the feed roller 5 with a predetermined pressure.

In this state, the multi-feed separation and feeding operation can be performed in the conventional manner.

As described above, according to the present invention, it is possible to easily take out the separation roller unit in which the separation roller and torque limiter are integrally provided when replacing the separation roller due to friction over time or during maintenance such as refueling the torque limiter or the like. As a result, serviceability becomes extremely good.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an example of a conventional friction roller separation paper feeding device, Fig. 2 is a longitudinal cross-sectional view showing an embodiment of the present invention, and Fig. 3 is a roller cover near the separation unit attachment part. A perspective view with the
FIG. 4 is a sectional view of the separation unit in an assembled state, and FIG. 5 is an exploded perspective view thereof. 4... Pick up roller, 5... Feed roller, 6... Separation roller, 13... Torque limiter, 14... Separation roller unit shaft, 19... Bracket, 20... Guide groove, 21...
Pressure arm, 22...pressure spring.

Claims (1)

[Scope of Claims] 1. A pick-up roller that presses against the top surface of a stack of sheets stacked on a paper feed tray of a copying machine and rotates in the paper feed direction, and a pick-up roller that is provided on the downstream side with respect to the paper feed direction and rotates in the paper feed direction. It comprises a rotating feed roller, and a separation roller which pinches the paper path and presses against it, and is applied with a constant torque in the opposite direction to the paper feeding direction by a torque limiter, and the separation roller and torque limiter are one roller. In the friction roller separation paper feeding device integrally provided on the shaft of the feed roller, the side facing away from the feed roller is open, and both ends of the shaft can be slidably and rotatably inserted and extend in the direction toward the feed roller. It is characterized by having a member having a guide groove and fixed to the machine frame, a member supporting a shaft having both ends inserted into the guide groove, and urging means for urging the member toward the feed roller. Paper feeding device.