Copying apparatus

• US 5,214,474 A
• Filed: 03/26/1992
• Issued: 05/25/1993
• Est. Priority Date: 03/28/1991
• Status: Expired due to Term

• Current Assignee: Mita Industrial Co., Ltd. (Kyocera Corporation)
• Original Assignee: Mita Industrial Co., Ltd. (Kyocera Corporation)
• Inventors: Ishizuka, Yoshiyuki
• Primary Examiner(s): Braun, Fred L.
• Assistant Examiner(s): Smith, Matthew S.
• Application Number:
  US07/857,763
• Time in Patent Office: 425 Days
• Field of Search: 355/219, 355/220, 355/203, 355/204, 355/207, 355/208, 355/228, 355/67, 355/69, 355/214
• US Class Current: 399/52
• CPC Class Codes: G03G 15/0266 Arrangements for controlling the amount of charge
• CPC Class Codes: G03G 15/043 with means for controlling illumination or exposure G03G15/041 takes precedence

Abstract

The intensity of a light emitted from a light source and reflected on a document is detected by an exposure sensor. A control section controls an exposure adjusting circuit to adjust an intensity of the light emitted from the light source based on a detection result of the exposure sensor, and simultaneously controls a potential adjusting circuit to adjust a potential of a surface of a photoconductive drum through a charging device.

Claims

1. A copying apparatus, comprising:

a photoconductive drum;

a charging device for charging the photoconductive drum;

a light source for emitting a light to expose a document;

a lens unit, through which light reflected on the document is transmitted to expose the photoconductive drum charged by the charging device to form an electrostatic latent image on the photoconductive drum;

a developing device for developing the electrostatic latent image;

exposure adjusting means for adjusting an exposure of the photoconductive drum to the light emitted from the light source and reflected on the document by changing an intensity of the light emitted from the light source;

potential adjusting means for adjusting a potential of the photoconductive drum through the charging device; and

control means for controlling the exposure adjusting means to adjust the exposure and simultaneously controlling the potential adjusting means to adjust the potential, based on the intensity of the light emitted from the light source and reflected on the document, wherein the exposure adjusting means is controlled to heighten the exposure and the potential adjusting means is controlled to lower the potential in the case that the intensity of the light is lower than a reference value, and the exposure adjusting means is controlled to lower the exposure and the potential adjusting means is controlled to heighten the potential in the case that the intensity of the light is higher than the reference value.

2. A copying apparatus according to claim 1, wherein the lens unit has a red filter, through which the light for exposing the photoconductive drum is transmitted.