Developing unit having ceramic donor roll
US5384627A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1994 |
| Grant date | Jan 24, 1995 |
| Priority date | — |
| Expiry date | Mar 21, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/0643
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A developer unit adapted to develop a latent image with toner particles. The unit includes a housing defining a chamber for storing a supply of toner particles in the chamber. The unit also includes a donor roll including an electrically non-conductive circumferential surface having a conductivity less than 10.sup.-8 (ohm-cm).sup.-1 and having a central region and opposed marginal regions disposed on either side of the central region with the diameter of the central region being less than the diameter of the opposed marginal regions. The donor roll is spaced from the latent image to form a development zone. The unit further includes an electrode member which is positioned in the development zone adjacent opposed marginal regions and spaced from the central regions of the donor roll. The electrode member is electrically biased to detach toner particles from the donor roll to form a toner powder cloud in the development zone with toner particles from the toner cloud developing the latent image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.