Image forming method and apparatus
US5409791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1993 |
| Grant date | Apr 25, 1995 |
| Priority date | — |
| Expiry date | May 20, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/0126
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An electrostatic image on an image member already containing a loose dry first toner image is toned with a second toner, for example, a toner of a second and different color from the first toner image. The toning is accomplished by a developer having a high coercivity permanently magnetized carrier and toner which is moved through a development zone by a rapidly rotating core inside a sleeve on which the developer moves. Pole transitions caused by the rapidly moving core make the high coercivity permanently magnetized carrier move vigorously in a wave motion having alternating crests and troughs. Scavenging of the first toner image is prevented by separating the sleeve from the image member sufficiently that the crests of the developer do not touch the image member during the toning process. An alternating electrical field is applied between the sleeve and the image member to enhance development.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.