IMAGE COMPENSATION METHOD AND APPARATUS FOR ELECTROPHOTOGRAPHIC DEVICES

• US 3,788,739 A
• Filed: 06/21/1972
• Issued: 01/29/1974
• Est. Priority Date: 06/21/1972
• Status: Expired due to Term

• Current Assignee: Samuel D. Coriale
• Original Assignee: Samuel D. Coriale
• Inventors: Coriale, Samuel D.
• Primary Examiner(s): Braun, Fred L.
• Application Number:
  US05/265,101
• Time in Patent Office: 587 Days
• Field of Search: 355/3,13,16,17 96/1R
• US Class Current: 399/48
• 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
• CPC Class Codes: G03G 15/065 Arrangements for controlling the potential of the developing electrode
• CPC Class Codes: G03G 15/5037 the characteristics being an electrical parameter, e.g. voltage

Abstract

A compensation method and apparatus wherein an electrometer probe is positioned in proximity to an exposed area of a charged photoreceptor surface. The probe is positioned only in that position of the area which is always light struck. Measurement of the surface potential and comparison of the surface potential to a fixed reference provides a control signal which can be employed to compensate charge, exposure, transfer and development.

Claims

1. A method of producing a control signal for compensating for parametric variation in a photoreceptor surface, the steps of which consist of, charging said surface, exposing an oversized area of said charged surface larger in size that the area normally required for the image to a pattern of radiation, electrostatically detecting the potential level of said oversized area at a point outside the area normally required for the image, comparing said potential level to a fixed potential to derive a control signal, and utilizing said control signal to compensate said photoreceptor surface for parametric variation.

2. In a parametrically compensated electrophotographic reproducing device, the combination comprising a charged photoreceptor surface, means for exposing said charged photoreceptor surface to radiation over an area of said surface, said exposed area including a first portion reserved for the latent image to be reproduced, and a second portion exposed to the same radiation but lying outside said first image portion, means electrostatically coupled to said second portion of said area for measuring the potential level of said second portion of said area, said potential level providing an indication of the parameters of said photoreceptor, and control means coupled to said electrostatically coupled measuring means for supplying a control signal in response to the potential level measured for compensating said reproducing device in accordance with variations in said photoreceptor parameters.

3. The combination of claim 2 wherein said measuring means comprises an electrometer including a probe, said probe electrostatically coupled to said second portion of said area.

4. The combination of claim 2 further including a fixed potential level, said control means being responsive to said fixed level and the potential level measured tO provide said control signal.

5. In a parametrically compensated electrophotographic reproducing device, the combination comprising a charged photoreceptor surface, first means for exposing said charged photoreceptor surface to a first radiation source defining an image over a first area of said surface, second means for exposing a second area of said charged photoreceptor surface to a second source of radiation of a fixed intensity corresponding to the maximum intensity of said first source, means electrostatically coupled to said second area for measuring the potential level of said second area, said potential level providing an indication of the parameters of said photoreceptor and control means coupled to said electrostatically coupled measuring means for supplying a control signal in response to the potential level measured for compensating said reproducing device in accordance with said photoreceptor parameters.

6. The combination of claim 5 wherein said measuring means comprises an electrometer including a probe, said probe electrostatically coupled to said second portion of said area.

7. The combination of claim 5 further including a fixed potential level, said control means being responsive to said fixed level and the potential level measured to provide said control signal.