process for the production of images on a elektrofotografisk medium, in particular a elektrofotografisk film, and apparatus for exercise of the procedure.

摘要

1438870 Electro-photographic process COULTER INFORMATION SYSTEMS Inc 5 June 1973 [8 June 1972] 26889/73 Heading G2H An electro-photographic process comprises charging a photo-conductive film F at 24 to a peak voltage, immediately after charging imagewise exposing (e.g. using a projector 56) and, immediately after exposure, toning at 84; a photo-cell 32 detecting image light intensity in order to control the peak voltage in inverse relation to the light intensity. The process is particularly intended for making high resolution microimages. Preferably the film comprises a Mylar (TRM) base coated with indium oxide then CdS. As shown, differential amplifier 36 is connected to photo-cell 32 and an electrometer 34 to control a relay 42 connecting voltage source 46 to coronade 24. When amp 36 terminates charging a shutter 58 is opened to expose the film and is closed when the charge on an unexposed area sensed by electrometer 34 has decayed to a predetermined level. As soon as exposure is terminated, liquid toner is pumped to a head 84 and applied under the influence of an electrode 92, whose bias is optionally controlled by electrometer 34. A pump 109 removes excess toner and a heater 126 fixes the image, In Fig.3 (not shown) a rotating drum (109) carries the various processing stations past the film.