Multicolor image forming apparatus with pulse voltage and DC voltage applied to a developing unit
US5557392A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 20, 1993 |
| Grant date | Sep 17, 1996 |
| Priority date | — |
| Expiry date | Dec 20, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/0121
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In an image forming apparatus of the type forming a multicolor toner image on an image carrier and then transferring it to a transfer medium at a time, a first developing unit develops a latent image with a developer of first color while a second developing unit develops a latent image with a developer of second color. The second developing unit has a developer carrier for depositing the developer of second color thereon, and a bias power source for applying to the developer carrier a bias voltage for development which changes periodically and has one period made up of a first and a second period of time. During the first period of time, the bias power source applies to the developer carrier a first voltage generating an electric field which causes the developer to fly toward the image area and non-image area of the image carrier in a gap between the image carrier and the developer carrier. During the second period of time, the power source applies a second voltage generating, in the gap, an electric field returning the developer having flied toward the non-image area during the first period of time to the developer carrier while preventing the developer of first color existing on …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.