Contact electrostatic photocopying process and apparatus forming reversed image master using web-type photoconductive surface
US4167326A · kind A · utility
Inventor
Key dates
| Filing date | Dec 29, 1977 |
| Grant date | Sep 11, 1979 |
| Priority date | — |
| Expiry date | Dec 29, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/228
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus is described by which photocopies can be obtained from documents and the like without the need for optical means for forming focused images of the documents. Essentially the process involves electrically charging a surface and subsequently applying thereto the document which is to be copied and exposing the document or the rear of the surface to light so as to cause the printed content of the document to form an electrical charge pattern on the surface by producing differential discharge of the electrical charge on the surface due to the contrasting regions in the printing on the document, and subsequently applying printing medium (toner) to the surface to cause it to adhere to the charged regions thereof and fixing the toner in place to form a reversed image master and then reprocessing the master in contact with a sheet of paper or other material the surface of which is photo-receptive by virtue of a layer of zinc oxide or the like which surface has first been electrically charged and exposing the master to light while doing so, so that an electrical charge pattern/image corresponding to content of the original document is formed on the surface of the sheet…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.