Electrophotographic image forming apparatus and electrophotographic image forming method

• US 20020001482A1
• Filed: 05/22/2001
• Published: 01/03/2002
• Est. Priority Date: 05/25/2000
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Iinuma, Kiyoshi
• Granted Patent: US 6,453,137 B2
• Time in Patent Office: Days
• US Class Current: 399/159
• CPC Class Codes: G03G 15/5008 Driving control for rotary photosensitive medium, e.g. speed control, stop position control
• CPC Class Codes: G03G 15/751 relating to drum G03G15/757 takes precedence
• CPC Class Codes: G03G 5/08214 Silicon-based

Abstract

An electrophotographic image forming apparatus comprises an amorphous silicon photosensitive drum showing a rotation starting torque held lower than a predetermined value (e.g., 0.39 N.m) in order to make the produced images free from unevenness and no molten developer would adhere to the photosensitive drum after long use so that the drum can be prevented from being scraped. The surface of the amorphous silicon photosensitive drum 1 is electrically uniformly charged and a laser beam LB is emitted from image exposure unit 3 to irradiate the surface of the photosensitive drum 1 and draw an electrostatic latent image there, which electrostatic latent image is then developed by developing unit 5, using toner. The image developed by toner is then transferred onto a receiving material 11 by transfer charger 6. A plurality of line grooves are formed on the outer peripheral surface of the drum-shaped aluminum base member of the amorphous silicon photosensitive drum 1 in parallel with each other around the circumference and an amorphous silicon photosensitive layer is formed on the surface thereof. The surface roughness is defined by Ra=0.08 to 0.12 μm.

Claims

1. An electrophotographic image forming apparatus comprising:

a photosensitive drum;

an exposure means for drawing an electrostatic latent image on the surface of said photosensitive drum;

a developing means for developing the electrostatic latent image on the surface of said photosensitive drum by means of developer;

a transfer means for transferring the image developed by means of developer onto a receiving material; and

a cleaning means for removing the developer remaining on the surface of said photosensitive drum after the transfer;

said photosensitive drum being driven to rotate so as to make a cycle of image forming operation proceed;

said photosensitive drum having a photosensitive layer of amorphous silicon with an arithmetical mean deviation of the profile of Ra=0.08 to 0.12 μ

m.

2. An electrophotographic image forming apparatus according to claim 1, wherein the ten-point height of irregularities of the surface of said photosensitive drum is Rz=0.45 to 0.75 μ

m.

3. An electrophotographic image forming apparatus according to claim 1 or 2, wherein

a plurality of line grooves having a triangular cross section are formed on the surface of the photosensitive drum and arranged around the circumference in parallel with each other.

4. An electrophotographic image forming apparatus according to claim 3, wherein

said line grooves are arranged at a pitch of 17 to 19 μ

m.

5. An electrophotographic image forming apparatus according to claim 1 or 2, wherein

said cleaning means includes a cleaning blade and a cleaning auxiliary member.

6. An electrophotographic image forming apparatus according to claim 5, wherein

said cleaning auxiliary member is a magnet roller for supplying developer to the photosensitive drum and located upstream relative to the cleaning blade.

7. An electrophotographic image forming apparatus according to claim 1 or 2, wherein

the rotation starting torque of said photosensitive drum is held not greater than 0.39 N.m.

8. An electrophotographic image forming apparatus comprising:

a photosensitive drum;

an exposure means for drawing an electrostatic latent image on the surface of said photosensitive drum;

a developing means for developing the electrostatic latent image on the surface of said photosensitive drum by means of developer;

a transfer means for transferring the image developed by means of developer onto a receiving material; and

a cleaning means for removing the developer remaining on the surface of said photosensitive drum after the transfer;

said photosensitive drum being driven to rotate so as to make a cycle of image forming operation proceed;

said photosensitive drum being driven with a rotation starting torque not greater than 0.39 N.m.

9. An electrophotographic image forming method for conducting a cycle of image forming operation by using an electrophotographic image forming apparatus comprising:

a photosensitive drum;

an exposure means for drawing an electrostatic latent image on the surface of said photosensitive drum;

a developing means for developing the electrostatic latent image on the surface of said photosensitive drum by means of developer;

a transfer means for transferring the image developed by means of developer onto a receiving material; and

a cleaning means for removing the developer remaining on the surface of said photosensitive drum after the transfer;

said photosensitive drum being driven to rotate with a rotation starting torque not greater than 0.39 N.m so as to make the cycle of image forming operation proceed.