JPS5924417B2 - Transfer device for sheet materials in copying machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a sheet-like object conveying device in a copying machine.

In a copying machine, particularly in a transfer type copying machine called PPC, a complete copy is created by transferring a toner image attached to a latent image forming drum onto copy paper and fusing it.

During this process, the copy paper stored in the paper feed box is
For example, the paper is sent out from the paper feed box by a friction roller or the like and transferred to the next stage. and the rear end.
At this time, in order to prevent slack in the copy and to speed up the copying process, it is often necessary to make the transport speed of the second stage roller located at the rear faster than that of the first stage roller. However, in all conventional roller devices, the roller and drive system are integrally connected, so if the transport speeds of the rollers in both stages are different, unnecessary slippage will occur between the roller and the copy paper. This causes transfer misalignment, insufficient feed amount, wrinkles, etc., and as a result, the quality of copying deteriorates or increases in speed are hindered.

As a solution to the problem explained above,
In Publication No. 5, a one-way clutch is interposed between the first stage roller device and the drive shaft to transmit only the driving force in the sheet transport direction, and the second stage roller device has a higher speed than the first stage roller device. A sheet transport device has been proposed in which a first stage roller device idles when transporting a sheet at high speed.

Although this proposal solves the above-mentioned problems to some extent, it is still insufficient to cope with higher speeds, to prevent transfer misalignment, to prevent wrinkles, etc.

That is, since only one one-way clutch is provided between the second stage roller and its drive shaft, the second stage roller rotates integrally in the width direction of the sheet even when it idles. Therefore, the state of sheet transport in the width direction of the sheet is not adjusted.

Due to this, transfer misalignment and wrinkles cannot be sufficiently prevented. Transfer misalignment here refers to the fact that the toner image formed on the photoreceptor is sufficiently sharp, but the toner image transferred to the transfer sheet is blurred or misaligned.
This phenomenon of low sharpness is mainly caused by poor adhesion between the photoreceptor and the transfer sheet at the transfer position.

The paper feeding device of a copying machine is manufactured under very strict performance checks because it is necessary to guarantee stable operation throughout its operating period and to ensure stable operation with various types of paper. This is common. Taking wrinkles as an example, even slight irregularities that can be visually observed are determined to be defective as a paper feeder.

In view of the severe conditions required of such a paper feeder for a copying machine, the paper feeder described in Japanese Patent Publication No. 414425 is still insufficient. The present invention has been made to improve the drawbacks of the prior art described above.

The present invention will be explained below based on one example.

In FIG. 1, 1 is a sheet-like object such as copy paper, 2 is a holding plate of a sheet-like object conveying device, which is swingably supported by a shaft 3, and is moved by gravity or a spring (not shown). It is always biased in the direction of force on the sheet-like material 1.

Reference numeral 4 denotes a drive shaft which is rotatably fitted to the distal arm portion of the holding plate 2. A motor 6 as a drive element includes a worm gear 7 provided on its output shaft and a worm gear 7 forming a power transmission means provided on the shaft. It is coupled via a worm wheel 5 provided.

Reference numeral 8 denotes a first group of friction rollers (transfer elements) made of an elastic material such as rubber, which contacts the sheet-like material 1, and which are arranged at intervals on the drive shaft 4 and are rotatable relative to each other. It is pivoted.

Reference numeral 9 designates a one-way transmission clutch interposed between the drive shaft 4 and each roller 8, in which the drive shaft 4 is moved by the motor 6 in the direction of arrow a.
Only when the rotation is rotated in the direction, the rotation is transferred to the first group roller 8.
is configured to communicate.

The clutch 9 may be a known single-force transmission clutch such as a ratchet mechanism using pawls and gears, a silent ratchet mechanism using a coil spring, or a ball ratchet mechanism.

In FIG. 2, 10a and 10b are the second group of friction rollers installed in the next stage C, and the speed at which the sheet-like material 1 is transported in the direction of arrow d is faster than that of the first group of rollers 8. It is determined.

11a and 11b are copy paper guide plates.

Now, when the motor 6 is operated in accordance with the predetermined timing of the copying process, the drive shaft 4 rotates in the direction of arrow a through the worm reduction mechanisms 7 and 5, and the first group roller 8 is rotated by the action of the one-way transmission clutch 9. Rotate in the direction of arrow b.

Therefore, the copy paper 1 is sent out in the direction of arrow c by the frictional force of the roller 8, is guided by the guide plate 11a as shown in FIG. The rear end portion is in contact with the first group roller 8, while the rear end portion is in contact with the first group roller 8. In this case, when the second group rollers 10a, b feed the copy paper 1 at a higher speed, the first group roller 8 is rotated faster than the drive shaft 4 due to the movement of the copy paper 1. , the transmission action of the one-way transmission clutch 9 is cut off, and each of the first group rollers 8 is maintained in a freely rotatable state.

(The same applies even after the motor 6 has stopped.) Therefore, even if both groups of rollers 8 and 10a, b are in contact with the copy paper 1 at the same time, no frictional interference occurs. As described above, when using the device according to the present invention, a one-way transmission clutch is provided for each of the first group of friction rollers, so that each of the first group of friction rollers can freely rotate when the second group of rollers transports a sheet. However, since the width force direction of the sheet is adjusted, troubles caused by poor paper feeding such as transfer misalignment and wrinkles are effectively prevented, and high-speed copying becomes possible.

[Brief explanation of the drawing]

FIG. 1 shows a perspective view of the main parts of an embodiment of the present invention, and FIG.
The figure shows an operational diagram. 1 is a sheet-like object, 2 is a holding plate, 3 is a shaft, 4 is a drive shaft, 5
is a worm wheel, 6 is a motor, 7 is a worm gear,
8 is a first group of friction rollers, 9 is a unidirectional transmission lug, 10
a and 10b are second group friction rollers, and 11a and 11b are guide plates.

Claims (1)

[Claims] 1. A sheet is sent out by a plurality of roller-like transport means arranged on a shaft connected to a drive means via a power transmission means, and the sheet is transported in a state where the rear end of the sheet is in contact with the roller-like transport means. In a sheet conveyance device for a copying machine configured to carry out subsequent sheet conveyance by another conveyance roller provided so as to be able to come into contact with the tip of the roller, the sheet conveyance speed of the other conveyance roller is set to a sheet feeding speed greater than the sheet feeding speed of the driving means, and a mechanism for transmitting only the driving force in the sheet transporting direction of the driving means to the plurality of roller-like transporting means between the shaft and the husbands of the plurality of roller-like transporting means. 1. A sheet-like material transfer device for a copying machine, characterized in that a directional clutch is interposed.