Electrostatic copying apparatus
US4591262A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1979 |
| Grant date | May 27, 1986 |
| Priority date | — |
| Expiry date | Sep 17, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/0291
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A primary corona charging unit (13) applies a uniform electrostatic charge to a photoconductive drum (12) prior to radiation of the drum (12) with a light image of an original document (26) to form an electrostatic image. The electrostatic image is developed and transferred to a copy sheet (31) by use of a corona transfer charger (14) and separation charger (16). An A.C. corona discharger (17) discharges the drum (12) prior to recharging by the primary charger (13). The primary charger (13) is de-energized prior to the end of a copying operation to prevent charging of non-image areas of the drum (12). The copying operation is terminated by stopping rotation of the drum (12) and simultaneously de-energizing all of the other corona chargers (14), (16), (17). At the beginning of a copying operation, the corona chargers (14), (16), (17) are energized simultaneously with starting rotation of the drum (12). The primary charger (13) is not energized until sufficient time has elapsed for the leading edge of a portion of the drum (12) charged by all of the other chargers (14), (16), (17) to reach the primary charger (13).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.