JP2837862B2 - Image carrier drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt-shaped image carrier driving device for an electrophotographic apparatus.

2. Description of the Related Art An endless belt-shaped image carrier is often used as an image carrier of an electrophotographic apparatus such as an electrophotographic copying machine, an optical printer, and a facsimile. For example, FIG. 4 shows a photoreceptor belt 1 as such an image carrier. Photoreceptor belt 1
Is wound around the driving roller 2 and the driven rollers 3 and 13, and one of the driven rollers (13 in the example shown in the figure) is centered on one point (the axis of the driven roller 3 in this example) by a spring 14. The photoreceptor belt 1 is provided at one end of the tension arm 15 that is biased to rotate, and presses the photoreceptor belt 1 outward to apply a predetermined tension.
As a material of the driving roller 2, chloroprene rubber or the like is employed.

As is well known, the peripheral surface of the photoreceptor belt is provided with equipment for performing each of the electrophotographic processes of charging, exposure, development, transfer, separation, cleaning, and static elimination. Is formed into a toner image by development, and is transferred to a transfer sheet fed to a transfer unit. Then, the transfer sheet is separated from the photoreceptor belt and fixed to complete recording.

Now, in an electrophotographic apparatus using a photoreceptor belt as a photoreceptor, when the photoreceptor belt is driven by a main motor that drives a transfer sheet conveying member, the torque fluctuation of the machine during the transfer of the transfer sheet may occur. As a result, unevenness in the speed of the photoreceptor belt was generated, and jitter was generated on the formed image, and an abnormal image was easily generated. This development occurs remarkably especially when thick paper is used as the transfer paper.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of an electrophotographic apparatus using an endless belt-shaped image carrier as an image carrier, and has a belt-shaped image even when a thick transfer paper is used. It is an object of the present invention to provide a photoconductor driving device capable of obtaining a good image with less jitter without causing uneven speed of the carrier.

Means for Solving the Problems In order to solve the above problems, a belt-shaped image carrier driving device of the present invention is provided with an inertia member rotatable integrally with a shaft of the driving roller, Power transmission from the member to the shaft of the drive roller is performed via a belt member and a pulley provided on the shaft so as not to contact the shaft of the drive roller, and between the pulley and the inertia member. An elastic connecting member is provided.

As described above, the inertia member rotatable integrally with the shaft of the drive roller of the belt-shaped image carrier is provided, and the elastic transmission member is interposed between the drive roller and its drive side member. Even when the speed fluctuation occurs in the side member, the speed fluctuation is not directly transmitted to the driving roller, and the driving roller can rotate while maintaining a constant speed by the inertial force of the inertia member, and as a result, the photosensitive member Is kept constant.

Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

In the apparatus of the embodiment described below, a photoconductor drive motor independent of a main motor for driving a transfer paper conveying unit, a fixing roller, and the like is provided as a photoconductor belt drive source.

FIG. 3 is a diagram showing an example of a mechanical drive system of such an apparatus. Driving the feed roller gear 16 directly connected to the feed roller, the feed roller gear 17 directly connected to the feed roller, the resist roller gear 18 directly connected to the registration roller, the transport belt 19 from the transfer section to the fixing section, and driving the fixing roller The fixing roller gear 20 and the like are all driven by a main motor (not shown) via a main motor gear train 11 and a gear train provided between the gears.

A photoconductor drive motor 4 is provided as a drive source for driving the drive roller 2 of the photoconductor belt 1, and drives the drive roller 2 that winds the photoconductor belt via the photoconductor drive belt 8 and the photoconductor drive pulley 7. The developing unit (not shown) is driven via a developing unit driving gear 21 and a developing unit driving belt 22 provided coaxially and integrally with the photoconductor driving pulley 7. As the photoconductor driving motor 4, a stepping motor is used. The stepping motor has the advantage of being inexpensive, but involves vibrations, so that it is necessary to prevent the vibrations from being transmitted to the photoconductor and causing speed unevenness.

FIGS. 1 and 2 show an embodiment of a photoconductor driving device in which the vibration of the photoconductor driving motor is prevented from being transmitted to the photoconductor.

The photoreceptor drive motor 4 is fixed to the apparatus main body side plate 10 with small screws 23, and is controlled for power supply and start / stop via a harness 24. A drive belt (for example, a timing belt) 8 having elasticity is provided between a pulley 4a provided on an output shaft of the drive motor 4 and a photoconductor drive pulley 7 provided coaxially with the drive roller 2 of the photoconductor belt 1. Has been passed over. The drive pulley 7 is elastically connected to a boss of an inertia member (flywheel) 5 which is integrally and coaxially fixed to one end of a drive connection shaft 9 which can be disengaged by being moved in the axial direction with the shaft of the drive roller 2. The rotation force is coupled via the member 6.

The joint between the shaft of the drive roller 2 and the drive connection shaft 9 is as follows.
In this embodiment, two pins are radially symmetrically implanted at the shaft end of the drive roller shaft, and axially at symmetrical positions distant from the axis at the end flange of the drive coupling shaft. When the photoconductor unit including the photoconductor belt 1, the driving roller 12, the driven roller 3, and the like is detached and attached in the axial direction, a configuration in which two provided pins are engaged and disengaged is used.
When it can be easily disengaged and rotates in one direction, the radial pin and the axial pin always keep contact, and the rotational movement of the drive coupling shaft is accurately transmitted to the drive roller.

In this embodiment, as the elastic connecting member, pins respectively implanted in the boss portions of the drive pulley 7 and the inertia member 5 are inserted into holes provided in a thick rubber disc so that they do not come into contact with each other. That is used.

However, as the above-mentioned detachable joint and elastic connecting member, various known members other than those having the above-mentioned structures can be used. In this embodiment, the inertia member 5 is made of brass and has a thickness of 8 m.
An boss is integrally formed on a disc having a diameter of 100 mm and a diameter of 100 mm. However, it is needless to say that dimensions and materials that can provide an optimum moment of inertia should be selected according to conditions.

Since this device is configured as described above, the vibration of the photoconductor driving motor 4
The drive roller 2 can be stably rotated by the inertia of the inertia member 5 because of being absorbed by the elastic connection member 6.

In the above-described embodiment, the configuration in which the photoconductor driving motor is provided separately from the main motor has been described. However, even in a system in which the photoconductor is driven via the clutch by the main motor, the photoconductor is rotated by the main motor. The present invention can be applied by replacing the pulley fixed to the output shaft of the photoconductor driving motor of the above-described embodiment with the driving pulley, and the rotation speed of the motor is changed by the torque fluctuation of the machine accompanying the transfer of the transfer paper. The unevenness is prevented from being transmitted to the photoreceptor belt, and the occurrence of jitter can be prevented.

Effects As described above, according to the present invention, the vibration of the belt-shaped image carrier driving source and the rotation unevenness caused by the transfer of the transfer paper are prevented from being transmitted to the image carrier, and the image is stably formed. The carrier can be rotated, and a good image without jitter can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view including a partial cross section showing the structure of a photoconductor driving device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, and FIG.
FIG. 4 is a side view showing a mechanical drive system of an electrophotographic apparatus in which the photoconductor driving device is used, and FIG. 4 is a side view showing a schematic configuration of a photoconductor belt and a supporting device thereof. DESCRIPTION OF SYMBOLS 1 ... Photoreceptor belt 2 ... Driving roller 3 ... Driving roller 4 ... Driving motor 5 ... Inertial member 6 ... Elastic coupling member (elastic transmission member) 8 ... Photosensitivity which has elasticity Body drive belt (elastic transmission member)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-228281 (JP, A) JP-A-63-177190 (JP, A) JP-A-57-151955 (JP, A) 40442 (JP, A) JP-A-62-125373 (JP, A) JP-A-64-52170 (JP, A) JP-A-60-49550 (JP, U) JP-A-62-185953 (JP, U) Actual Opening Sho 61-137 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/00 550 G03G 21/00 350-352 G03G 21/16-21/18

Claims (1)

(57) [Claims] 1. An electrophotographic apparatus, comprising: a belt-shaped image carrier that is wrapped around a driving roller and a driven roller and moves, and transfers a toner image formed on the image carrier to a transfer sheet. In the driving device for the belt-shaped image carrier, an inertia member is provided so as to be rotatable integrally with the shaft of the driving roller. Power transmission from the driving side member of the driving roller to the driving roller shaft is performed by the belt member. An image carrier, which is provided via a pulley provided on the drive roller so as not to contact the shaft of the drive roller, and an elastic connecting member is arranged between the pulley and the inertial member. Body drive.