AUSTRALIA SECRETARY DEPARTMENT OF SUPPLY ELECTROSTATIC PRINTING METHOD CRYSTALLIZATION APPARATUS

摘要

1447280 Electrographic printing AUSTRALIA DEPT OF SUPPLY SECRETARY OF 26 Sept 1973 [28 Sept 1972] 45175/73 Heading B6C In a method of printing from electrical images the image on a dielectric surface is first developed with a conductive developer and then fixed to form a printing master having areas of relatively high and relatively low dielectric constant defining the image. The master is inked in the presence of an electrical field having a polarity to urge the ink on to the surface of the master where it is retained in the areas of relatively low dielectric constant. The ink is then transferred from the master to a receiving sheet in the presence of a further electrical field. The inking and transferring steps are then repeated as required. The original image may be an electrostatic image produced on the surface of a photoconductive material by charging and light exposure, the development being effected by transfer of liquid conductive developer from the surface of a roller. Alternatively the master may be produced from a sheet 10 bearing an image 16 printed by letterpress, lithography or electrophotography by passing a roller 12 bearing conductive developer 14 over the sheet 10 whilst it is in contact with an electrode 11. An electric field is created between the roller and the electrode 11 causing the developer to be selectively deposited in the insulating areas 15. In printing from the master on to a sheet 23, Fig. 3, ink is transferred from a roller 21 on to the master supported on a roller 20 under an electrical bias and the inked image is transferred to the receiving sheet 23 supported on an electrode 24 under a further electrical bias. Examples of ink and developer formulations and suitable electrical biases are given.