GB1276749A - Electrophotographic recording apparatus - Google Patents

Abstract

1276749 Electrostatic recording mirror galvanometer HONEYWELL Inc 29 Oct 1969 [31 Oct 1968(3)] 52868/69 Heading G1J [Also in Division G2] A recording mirror galvanometer, in which a signal may be recorded on ordinary photographic paper, is converted for electrophotographic recording by the addition of a charging unit and a liquid development unit comprising a container having a bottom opening covered by a permeable membrane. Light from lamp 32 is focused upon mirrors 34 of a plurality of galvanometers 30 to which a signal is applied to accordingly reflect a beam to a recording paper either via pivotable mirror 75 for normal photographic recording or via mirror 36 for electrophotographic recording. In the latter case photo-conductive paper 12 is fed from roll 14 by a variable speed drive past charger 20 and the exposure station to a liquid developer applicator 42 comprising a container 46 of a suspension of toner particles, charged oppositely to paper 12, in an insulative liquid. The bottom of container 46 contacts sheet 12 and is formed by a curvilinear screen 48 covered on the inside by a permeable membrane 50 which may be of felt, wool &c. Membrane 50 is thin enough to allow transfer of liquid at the fastest speed of paper 12 but is thick enough to prevent leakage when the recording paper 12 is stopped. With the toner so charged it is stated that particles adhere only to the areas of charge gradient at the edges of the lines produced by relative movement of the light spot and the paper 12. Longitudinal grid lines may be recorded using grid filter 61, mirror 59 and lens 60 and timing marks may be recorded being pulses from flash-tube 74. To compensate for different paper speeds through charger 20 which results in different charge densities on sheet 12, the sheet may be uniformly illuminated by another lamp to dissipate some of the charge on the sheet, the amount depending on the paper speed. In a second embodiment Fig. 5 (not shown) the same optical elements are used for the two recording methods.