Gas-supported electrographic writing head
US4905026A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 17, 1989 |
| Grant date | Feb 27, 1990 |
| Priority date | — |
| Expiry date | Feb 17, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/323
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A writing apparatus for forming an electrostatic latent image on a charge-retentive image carrier in which the writing head is biased by a force so that the writing head tends to contact the image carrier, thereby blocking a gas opening operatively associated with the writing head. A stream of pressurized gas is projected from the gas opening and the escaping air provides a counterforce which moves the writing head away from the image carrier until an equilibrium position is reached in which the writing head is preferably spaced apart from the image carrier by a predetermined very small distance. Typically, the image carrier is a sheet of paper supported on a rotatable drum, but the image carrier may be paper drawn from a roll of paper and resiliently biased against the writing head. The latent image is written by a plurality of selectively energized charging elements that terminate at an outlet side of the writing head. The outlet side has first and second bearing surfaces which are spaced apart to define the gas opening.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.