JPH06149137A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate the occurrence of noise due to the combination of gears and irregularities in an image due to poor accuracy of the gear and also to miniaturize the device and reduce the power consumption by applying an ultrasonic motor for a photosensitive body driving device. CONSTITUTION:A rotor 41 being the component of the ultrasonic motor is fixed at the one inner side of the photosensitive body 47. A stator is constituted of an elastic vibrator 42, a piezoelectric ceramics 43 and an electrode plate 44a, and it is fixed on a side plate 46 through an insulating plate 45. A lead wire 44b for impressing a voltage on the piezoelectric ceramics 43 is attached with the electrode plate 44a. The lead wire 44b is connected with the control part of the motor through a shaft 50. Pressing the rotor 41 and the elastic vibrator 42 of the stator is adjusted by a pressing spring 48 which is inserted in between the side plate 55 on the other end of the photosensitive body part 47 and the guide plate 54. Thus, the photosensitive body part 47 can be directly driven at a low speed without the need of plural gears.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body driving device for an image forming apparatus such as a copying machine or a printer.
In particular, it relates to the application of various ultrasonic motors as the rotating body driving device.

[0002]

2. Description of the Related Art A rotary body driving device included in a conventional image forming apparatus is composed of a rotary body, an AC motor, a reduction gear and the like. The rotation speed of the rotating body is reduced by the high-speed rotation of the AC motor through several stages of gears.
Controlled.

[0003]

Therefore, there is a problem in that it is necessary to secure the installation places of the gears of several stages in the image forming apparatus, and the image forming apparatus becomes large in size. In addition, there is a problem that noise is generated by combining gears of several stages and an image is disturbed due to inaccuracy of gears, and further, mechanical components are increased and reliability is deteriorated.

Further, although the stepping motor has good controllability, it vibrates a lot during low-speed driving, causes noise in the image forming apparatus, and causes a disturbance in the image due to a decrease in positioning accuracy due to the vibration.

On the other hand, in an embodiment such as a DC motor, there is a distributed direct drive system. This configuration aims at downsizing the rotating body driving device by making the best use of the low speed rotation and high torque of the DC motor, but this configuration involves high power consumption due to the low speed rotation of the DC motor.

[0006]

In order to solve the above-mentioned problems, in the image forming apparatus of the present invention, the rotating body driving device has the characteristics of low rotation and high torque, and has a simple structure with few mechanical parts. A sonic motor is adopted, and the rotor of the image forming apparatus and the rotor, which is one mechanical component of the ultrasonic motor, are integrated to enable low-speed direct drive of the rotor. That is, the rotor of the ultrasonic motor is fixed inside the rotating body, and the stator is fixed on the main body side that holds the rotating body. Therefore, the image forming apparatus is configured such that the ultrasonic motor and the rotating body are integrated, that is, the rotor of the ultrasonic motor is the rotating body.

[0007]

[First Embodiment] FIG. 1 shows an embodiment of an image forming apparatus in which an ultrasonic motor is applied to a photosensitive member 4 which is one of the rotating members of the image forming apparatus. That is, FIG. 1 shows an original table 1 for drawing a latent image on the photoconductor 4, a short focus lens eye 2,
The transfer material P has a light source 3, a developing device 6 for developing a latent image on the photoconductor 4 as a visible image, and a transfer charger 9 for transferring the visible image to the transfer material P. The photoconductor 4
A sheet feeding roller 7 and a sheet feeding roller 8 for feeding a visible image, and a conveying unit 10 for conveying the transfer material P on which the visible image is transferred, and a fixing device 11 for fixing the transferred visible image. The image forming apparatus has a sheet discharging section 12 for discharging the transfer material P having the visible image fixed thereon and a cleaning section for cleaning the photoconductor 4.

Here, the copying operation of the image forming apparatus will be briefly described. After placing the document on the document table 1,
The transfer material P is loaded on. A copying operation is started at a predetermined timing by an image formation start command (not shown). First, the transfer material P is conveyed to the transfer position by the paper feed rollers 7 and 8. After that, the document table 1 reciprocates by turning a sensor (not shown) on and off, and the document placed on the document table 1 is exposed. Further, in synchronization with the operation of the document table 1, the ultrasonic motor also operates according to the rotation command, and the photoconductor 4 rotates. At the same time, a latent image is formed on the photoreceptor 4, and the latent image is made visible by the developing device 6. The visible image on the photoconductor 4 is transferred to the transfer material P by the transfer charger 9. After that, the transfer material P is transported to the fixing device 11 by the transport unit 10 and fixed, and then the transfer material P is discharged to the paper discharge unit 12. After that, the photoconductor 4 is cleaned by the cleaning unit 13 and is positively or negatively charged by the primary charger 5.

This series of copying operations is performed in a predetermined sequence (not shown).

FIG. 2 shows the details of the cross section of the photosensitive member 4 of the image forming apparatus. The rotor 51, which is a component of the ultrasonic motor, is fixed inside one side of the photoconductor portion 56. The stator is made of elastic vibrating body 52 and piezoelectric ceramics 53.
And an electrode plate 58b, and is pressed against the rotor 51 by a pressure spring 57 via an insulating plate 54.
A lead wire 58a for applying a voltage to the piezoelectric ceramics 53 is attached to the electrode plate 58b. The lead wire 58a is connected to the motor controller via a shaft 60 and bearings 59 and 61. The other end of the photoconductor portion 56 is supported by a bearing 62 and a shaft 63.

With this configuration, the photosensitive member 56 and the ultrasonic motor are integrated to form the photosensitive member 4, and the low-speed direct drive can be performed by the known ultrasonic motor driving means without using gears of several stages. The rotation speed of the ultrasonic motor can be easily controlled by changing the voltage applied to the piezoelectric ceramics.

FIG. 3 is an exploded view of the ultrasonic motor portion which is the mechanical component of FIG.
Is an elastic vibrator, 102 is a piezoelectric ceramic, and 103 is an electrode pattern of the piezoelectric ceramic.

[Second Embodiment] FIG. 4 shows a second embodiment of the image forming apparatus.

A rotor 41 which is a component of an ultrasonic motor
Is fixed inside one side of the photoconductor portion 47. The stator is composed of the elastic vibrating body 42, the piezoelectric ceramics 43, and the electrode plate 44a.
It is fixed at 6. A lead wire 44b for applying a voltage to the superpiezoelectric ceramics 43 is attached to the electrode plate 44a. The lead wire 44b has a shaft 50 and a bearing 4.
It is connected to the control unit of the motor via 9, 51. The pressure applied to the rotor 41 and the stator 42 is adjusted by the pressure spring 48 inserted between the side plate 55 and the guide plate 54 at the other end of the photoconductor portion 47.

This structure also has a feature that, like the first embodiment, the photosensitive member portion 47 can be directly driven at a low speed without using several gears. The rotation speed of the ultrasonic motor can also be easily controlled by changing the voltage applied to the piezoelectric ceramics. Further, by arranging the pressure spring on the side opposite to the stator, the stator side becomes simpler than the mechanism shown in FIG. 1, and there is also an effect that the work time when replacing the photoconductor can be shortened. Further, since only the rotor is attached to the photoconductor, it is cost effective.

[0016]

As described above, the miniaturization of the image forming apparatus can be realized by applying the ultrasonic motor to the rotating body driving device of the image forming apparatus. This downsizing of the image forming apparatus is effective in reducing the mechanical parts of the image forming apparatus,
In addition, it is effective for cost reduction.

Further, unlike the AC motor, the ultrasonic motor has no inertial force due to the start and stop of the motor, so that the control of the rotating body driving device is easy. Therefore, it is possible to reduce image distortion due to poor precision of mechanical parts.

The drive current of the ultrasonic motor is small,
In addition, since there is no vibration during low-speed driving and the driving sound is quiet, a low power consumption type, noise reduction type, and vibrationless type image forming apparatus can be configured.

[Brief description of drawings]

FIG. 1 is a schematic view of an image forming apparatus showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a photoconductor driving mechanism of the first embodiment.

FIG. 3 is a diagram showing an ultrasonic motor of the photoconductor drive mechanism of FIG.

FIG. 4 is a diagram showing a photoconductor driving mechanism of a second embodiment.

[Explanation of symbols]

In FIG. 1, 1 ... Original platen 2 ... Short focus lens array 3 ... Light source 4 ... Photosensitive member 5 ... Primary charger 6 ... Developing device 7, 8 ... Paper feeding roller 9 ... Transfer charger 10 ... Conveyor 11 ... Fixing device 2 ... Paper discharging unit 13 ... Drum cleaning unit In FIG. 2, 51 ... Rotor 52 ... Elastic vibrating body 53 ... Piezoelectric ceramics 54 ... Insulating plate 55 ... Side plate 56 ... Photosensitive member section 57 ... Pressure spring 58a ... Lead wire 58b ... Electrode plate 59, 61, 62 ...
Bearings 60, 63 ... Shafts in FIG. 3 100 ... Rotor 101 ... Elastic vibrating body 102 ... Piezoelectric ceramics 103 ... Electrode pattern of piezoelectric ceramics 41 In FIG. 4, 41 ... Rotor 42 ... Elastic vibrating body 43 ... Piezoelectric ceramics 44a ... Electrode plate 44b ... Lead Wire 45 ... Insulating plate 46, 55 ... Side plate 54 ... Guide plate 47 ... Photosensitive member part 48 ... Pressure spring 50, 52 ... Shaft 49, 51, 53 ...
bearing

Claims (3)

[Claims] 1. A photosensitive member has a rotor fixed inside the photosensitive member, and a stator portion press-contacted with the rotor to form an ultrasonic motor. The stator portion includes the photosensitive member. An image forming apparatus, characterized in that the image forming apparatus is fixed to the main body side that holds the. 2. The image forming apparatus according to claim 1, wherein a rotor is formed at an end of the rotating body, and a bearing for supporting the rotating body is provided at the other end. 3. The image forming apparatus according to claim 1, further comprising a spring member for pressing the rotor and the stator, the spring member being disposed on the bearing member side.