GB1216111A - Automatic electrophotographic apparatus - Google Patents

Abstract

1,216, 111. Electro-photographic apparatus. RCA CORPORATION. March 27, 1968 [March 30, 1967], No.14756/68. Heading G2H. An electro-photographic method of producing a print of an object, e.g. amulti-colourtransparency, comprises forming sequentially a plurality of different superimposed electrostatic latent images on a record medium each image corresponding to a different portion of a composite image of the object and each latent image being separately developed. An automatic apparatus for producing multi-colour prints is shown in Fig. 1 Record medium transport and exposure. A record medium 12, comprising a photo-conductive layer 11 on a conductive backing, is drawn from a reel 64 and held, by suction, on a metal platen 62, and exposed to light, from a multi-colour original (17) in a slide holder 18 in a projector 20, through one of colour filters 28-30, 32 and 34 in a filter wheel 36, to form a latent image. Exposure Test. A test filter is moved into position below lens 39 of a projector 20, and the amount of light passing through it is sensed by a photo-cell 60 whose output signal drives control apparatus 52 to energize a motor 54 to adjust lens aperture 39 to the required setting. During this time, a processing head 90, shown in Fig. 8, on a carriage 144, moves leftwards over platen 62. The head 90 is then driven to the right by a motor 160, Fig. 4 (not shown) and photo-conductive layer 11 is simultaneously rinsed and charged prior to the latent image formation. The processing head 90 comprises a corona charger 126, fluid applicator 92 and fluid removal means 94. Development. The fluid applicator 92 comprises an insulating block 99, disposed within a slot, 95, Fig. 7 (not shown) which forms the fluid removal means, and a plurality of flexible tubes 104, 106, 108, 110, 112 communicating with separate openings in the block, which openings in turn communicate with a metal manifold 114, Fig.7 (not shown) having a slit (115) through which toner or rinse liquids flow on to layer 11. The fluid removal slot (95) communicates via a conduit (118) with a hose 122 connected to a vacuum pump 124, Fig.2 (not shown) to remove excess toner or rinse fluid. The latent image, formed by exposure through one of the colour filters, is developed with a corresponding toner, through one of the flexible tubes, respectively connected via solenoid valves, 104b-112b to tanks 104a-112a. As head'90 reciprocates over layer 11, the developed image is rinsed to reduce the thickness of the toner layer to less than 3 microns, the medium is recharged, the filter wheel stepped to another filter, and the process repeated for each filter, the latent image formed being developed with a correspondingly coloured toner. A circuit Fig.13 (not shown) automatically controls all of the different steps of the process, and shuts off the machine when the final print, comprising superimposed developed layers of different colours is fed out of the machine.