Electrostatic copying machine comprising improved magnetic brush developing-cleaning unit
US4142165A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 1977 |
| Grant date | Feb 27, 1979 |
| Priority date | — |
| Expiry date | Mar 22, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2221/0005
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A magnetic brush is used to develop a toner image on a photoconductive drum and subsequently to remove residual toner substance from the drum. An electrode roller is disposed closely adjacent to the magnetic brush between a developing tank containing the toner substance and the drum in the direction of rotation of the magnetic brush. For cleaning the drum, an electric potential is applied between the magnetic brush and the electrode roller which causes toner substance to be transferred from the magnetic brush to the electrode roller, thereby reducing the amount of toner substance on the magnetic brush and improving the cleaning effect. For development, the electric potential may be reversed to transfer the toner substance from the electrode roller back to the magnetic brush to increase theamount of toner substance thereon. Alternatively, the toner substance may be removed from the electrode roller for recycling and no transfer effected between the magnetic brush and the electrode roller during development. As yet another alternative, the electric potential may be varied during development in accordance with sensed image density on the drum to transfer toner substance from the magne…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.