Electrophotographic copiers
US4821071A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1987 |
| Grant date | Apr 11, 1989 |
| Priority date | — |
| Expiry date | May 7, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/083
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An improved electrophotographic copier is proposed which includes a first static charger; an image exposure unit; a second charger provided with a grid; and a developer having a developing electrode, all being arranged around a photosensitive rotatable drum. The second charger is impressed selectively with an a.c. voltage or a d.c. voltage which has an opposite polarity to that applied to the first charger. The voltage impressed to the grid has same polarity with that which is applied to the first charger. The developing agent contained in the developer includes such statically charged toner as having an opposite polarity to that of static latent images formed on the drum surface. The copier operates selectively in standard copy mode or in marginal image outline formation mode. The developing service is nevertheless carried out in the normal manner, thus employing no reverse development mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.