Electrostatic copying machine
US4084899A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1977 |
| Grant date | Apr 18, 1978 |
| Priority date | — |
| Expiry date | Apr 12, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/22
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An electrostatic image is formed on a rotating photoconductive drum and developed a number of times to form toner images which are transferred to respective copy sheets. The drum is rotated at a first speed for exposure and development of the first toner image and thereafter at a second higher speed for development of the subsequent toner images. A magnetic brush applies the toner substance to the drum, and is rotated at a third speed when the drum is rotated at the first speed and at a fourth speed which is higher than the third speed when the drum is rotated at the second speed, thereby applying more toner substance to the drum at the higher speed and maintaining the copy density constant. Alternatively or in combination, a bias voltage applied to the magnetic brush may be reduced at the higher drum speed, also resulting in the application of more toner substance to the drum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.