Transfer apparatus having a transfer member with vacuum means
US5155535A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1989 |
| Grant date | Oct 13, 1992 |
| Priority date | — |
| Expiry date | Jul 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/1685
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A transfer member, for example, a transfer drum utilizes a vacuum applied through vacuum openings to the drum surface for holding a receiving sheet. A toner image is transferred to the sheet under the urging of an electric field. The vacuum openings are made small enough to prevent a visible artifact caused by nontransfer of toner in the vicinity of the opening but large enough to still maintain a vacuum contributing to the holding force of the sheet. According to a preferred embodiment, larger vacuum holes are formed in the drum and a conductive insert defining or helping define small vacuum openings is inserted in each vacuum hole. The insert maintains the continuity of the electric field in the hole region, but its geometry provides the small openings to maintain the vacuum. The invention is particularly useful in apparatus in which more than one color toner image is transferred in registry to the receiving sheet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.