JP2005337367A - Gear driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear driving device for transmitting driving force to a photoreceptor whereby reduction of the cost, miniaturization and reduction of weight can be achieved, and rotation can be accurately controlled without being influenced by the disturbance. <P>SOLUTION: A conductive driving gear and a conductive driven gear meshed with the driving gear are driven through electrorheological fluids, an electric field is applied to the electrorheological fluids, and thereby a coefficient of viscosity thereof can be variably controlled. More concretely, the electric field applied to the electrorheological fluids coated on a meshed part of the conductive driving gear and the conductive driven gear is controlled to have optimum damping properties in accordance with the meshing error measured by a rotary encoder attached on the driving gear and the driven gear. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gear driving device for transmitting a driving force to a photoreceptor used in an electrophotographic image forming apparatus.

  In an electrophotographic image forming apparatus used for a copying machine, a printer, a FAX, or the like, an image defect (banding phenomenon) occurs due to a rotational speed fluctuation (rotational unevenness) of a photosensitive member, which is a rotating body, and image quality. Is significantly reduced.

  Although the photosensitive member should be driven at a constant rotational speed, a meshing error occurs between the driven gear integral with the photosensitive member and the driving gear that drives the photosensitive member, thereby changing the rotational speed of the photosensitive member. This variation appears as scanning unevenness when writing to the photoconductor with a semiconductor laser, causing image defects.

  An example of a conventional solution is disclosed in Patent Document 1. This is composed of a drive member and a driven member, and these members are connected by an elastic member and a fluid-filled vibration-proof member to transmit the rotational drive force of the drive source evenly.

  Another example is disclosed in Patent Document 2. In this configuration, the photosensitive member driving gear and the photosensitive member flange portion are connected via an elastic body, and the rotation speed fluctuation of the photosensitive member is prevented by a simple mechanism.

JP 11-101308 A JP 2003-36007 A

As means for reducing the rotational speed fluctuation of the photosensitive member, there are the use of a high-precision gear, the use of a flywheel, and the incorporation of an elastic member in the middle of the drive system to absorb the speed fluctuation. It is expensive and has difficulty in quality control. The use of a flywheel is inevitable in terms of size and weight, and requires a large torque at startup. In addition, the incorporation of the elastic member into the drive system is to dissipate the vibration energy by converting it into heat energy, but it is greatly affected by disturbances and the like, and there is a problem in its control and effect prediction. In any case, high cost, large size and complexity of the apparatus, and difficulty in predicting the effects are involved.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the intended process is a low-cost, compact, lightweight, unaffected by the influence of disturbances, etc. and capable of controlling the rotation with high accuracy. Another object of the present invention is to provide a gear driving device for transmitting the driving force of the gear.

  In order to achieve the above object, the invention according to claim 1 drives an electroconductive drive gear and an electroconductive driven gear meshing with the drive gear via an electrorheological fluid, and applies an electric field to the electrorheological fluid. Thus, the viscosity is variably controlled.

  According to a second aspect of the present invention, in the first aspect of the present invention, an electric field applied to the electrorheological fluid applied to a meshing portion of the conductive drive gear and the conductive driven gear is the drive gear and the driven gear. Control is performed so as to obtain optimum vibration damping characteristics according to a meshing error measured by a rotary encoder attached to the gear.

  According to the present invention, the viscosity is variably controlled by applying an electric field to the electrorheological fluid as a medium for driving the conductive drive gear and the conductive driven gear meshing with each other. As a result, the photosensitive member always rotates stably, it is possible to form a stable image on the photosensitive member, and it is possible to flexibly cope with changes in process speed. Become.

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

<Embodiment 1>
FIG. 1 shows a schematic diagram of a gear driving device according to the present invention.

  As a material used for the conductive drive gear 21 and the conductive driven gear 22, a conductive material such as a conductive resin material or a metal material is used. As shown in FIG. 2, the electro-viscous fluid 50 is applied to the entire tooth portion of the electroconductive drive gear 21 and the electroconductive driven gear 22, and the electro-viscous fluid 50 having a constant thickness is always held between the meshing portions. The Electrorheological fluids are roughly classified into dispersed systems and homogeneous systems, but a homogeneous system that can be used between very narrow electrodes like a lubricating oil is used.

  The conductive drive gear 21 is driven by the drive motor 1. The conductive driven gear 22 is fitted to the photosensitive member shaft 41, and the conductive driven gear 22 and the photosensitive member 4 rotate together.

  The driving force of the drive motor 1 finally drives the photoconductor 4 through the electrorheological fluid 50 sandwiched between the conductive drive gear 21 and the conductive driven gear 22.

  As shown in FIG. 3, the conductive drive gear 21 and the conductive driven gear 22 can generate an electric field at the meshing portion when energized from the power supply 12, and the viscosity of the sandwiched electrorheological fluid 50 is variable. To control. As a result, the meshing error is reduced, and fluctuations in the rotational speed of the photoreceptor 4 can be reduced.

<Embodiment 2>
In addition to the first embodiment, as shown in FIG. 4, the rotary encoder 11 is attached to each of the conductive drive gear 21 and the conductive driven gear 22 to detect the rotation speed and output it to the control unit 10. The meshing error is calculated. Then, the electric field applied at the meshing portion is controlled so that the meshing error is minimized, and the viscosity of the electrorheological fluid 50 is controlled to a value corresponding to the meshing error. As a result, the meshing error is reduced, and fluctuations in the rotational speed of the photoreceptor 4 can be reduced.

It is a whole block diagram of the Example of this invention. It is a meshing part enlarged view of a conductive drive gear and a conductive driven gear. It is a block diagram for the electric field control to a meshing part. It is a block diagram for control by a rotary encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive motor 4 Photoconductor 10 Control part 11 Rotary encoder 12 Power supply 21 Conductive drive gear 22 Conductive driven gear 41 Photoconductor shaft 50 Electrorheological fluid

Claims (2)

  A conductive drive gear and a conductive driven gear meshing with the drive gear are driven via an electrorheological fluid, and an electric field is applied to the electrorheological fluid to control the viscosity variably. Gear drive.   The electric field applied to the electrorheological fluid applied to the meshing portion of the conductive drive gear and the conductive driven gear is converted into a meshing error measured by a rotary encoder attached to the drive gear and the driven gear. 2. The gear driving device according to claim 1, wherein the gear driving device is controlled so as to obtain an optimum vibration damping characteristic.

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