Electrostatographic apparatus comprising improved developing bias control
US4213693A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 1979 |
| Grant date | Jul 22, 1980 |
| Priority date | — |
| Expiry date | Jan 23, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/065
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photoconductive drum (12) is electrostatically charged and radiated with a light image of an original document (16) to form an electrostatic image. The average value of the electrostatic potential of the electrostatic image is sensed and a developing bias voltage controlled in accordance therewith. The bias voltage is progressively increased when the sensed electrostatic potential is below a predetermined value and is reduced to a lower value when the electrostatic potential exceeds the predetermined value. The electrostatic potential is below the predetermined value for original documents constituted by printed pages and above the predetermined value for original documents constituted by photographs and other continuous tone documents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.