Patent GB-1183041-A (GB)
Title: Priting Apparatus
Inventor: DAVIS PAUL FRANK
IPC: B41J2/43
Filed: 1965-12-24
Abstract: 1,183,041. Selective printing. INTERNATIONAL COMPUTERS Ltd. 23 March, 1967 [24 Dec., 1965], No. 54838/65. Heading B6F. A selective electrographic printer is provided with an endless non-magnetic band 28, Fig. 1, moving along a horizontal path and carrying a supply of magnetic dust particles for deposition on the undersurface of a recording medium 10 of paper or plastics material when the recording medium which is moved in spaced parallel relationship above the endless band is subjected to electrostatic or electromagnetic forces generated by an array of electrodes 19 to cause the particles to adhere at selected areas on the recording medium to form characters which are subsequently fixed, then the recording medium has been advanced past a fixing station 39. Matrix head printers; electric input signals; electrographic printing; web guiding and feeding arrangements; multiple type surface selection.- The recording medium 10, Fig. 1, is drawn off a supply roll 11, passed through a first buffer reservoir 12 and coated in front of a guide roller 13 by an adhesive which is dispensed from a spraying head 38 and which may include a synthetic resin, modified linseed oil used in printers ink or cellulose acetate dissolved in acetone. The recording medium is then passed over guide rollers 14, 15 in closely spaced relationship with the endless band 28 moving at a faster rate than the recording medium such that the dust particles are adhered in selected areas opposite gaps 22 of selectively energized electromagnetic electrodes 21 to form an array of dots, conforming to the shape of selected characters, on the recording medium. The electrodes 21 are arranged in a transverse row and actuated selectively through a channel 25 by a coder/decoder 24 in response to signals generated by a computer linked input/output signal device 26. The successive selective actuation of electrodes as the recording medium is driven past the electrodes 21 produces an electrographic record of characters as shown in Fig. 3. The charge on the recording medium 10 prior to its entry to the array of electrodes 19 is controlled or modified by a pair of electrodes 36, 37. The electrographic characters are fixed in a fixer 39, which may be a hot air jet. In a modification the array of electrodes 19 may have three rows of electrodes (20, Fig. 4), which are staggered transversely with respect to the recording medium and associated with respective delays so that e.g. a full line of characters can be recorded when the respective electrodes are energized. In a further modification only one row of electrodes (20, Fig. 6) is used and the array is reciprocated transversely in synchronism with the movement of the recording medium 10. In a still further modification the record medium 10 is replaced by an endless intermediate magnetic band 200, Fig. 10, on which the latent electrographic images are formed adjacent the electrodes 20 and the magnetic dust carrying band 28, whereupon the endless band 200 is brought into rolling contact with the recording medium 10. Checking correctness of selection.-The use of the coder/decoder 24, Fig. 1, and input/output signal device 26 in conjunction with a further set of electrodes 20 permits of reading the electrographic characters to provide an error checking means. Type-wheel machines.-In the embodiment shown in Fig. 11, the array of electrodes 19 is replaced by a rotary drum 300 disposed above a trough 303, which produces a fluidized bed of magnetic dust particles supplied from a nozzle 34 and deposited on the drum in the selectively charged areas on the surface of the drum which is then rotated into impression with the recording medium 305.