GB855834A - Improvements in or relating to printing mechanisms - Google Patents

Abstract

855,834. Facsimile printing systems. INTERNATIONAL BUSINESS MACHINES CORPORATION. Feb. 11, 1958 [Feb. 13, 1957], No. 4417/58. Class 40(3). [Also in Group XVI] In an arrangement for printing in closely spaced columns on a moving record medium the printing mechanism comprises a continuously rotatable cylinder carrying a helical printing surface associated with a movable printing hammer, the record medium being fed between the cylinder and the hammer, and an electroadhesive clutch is selectively operable to establish a driving connection to propel the hammer towards the cylinder to effect printing on the record medium disposed between the cylinder and the hammer. For simultaneous printing in a number of columns, a corresponding number of hammers is associated with helical surfaces arranged to traverse the faces of all the hammers a number of times during a revolution of the cylinder. In the arrangement shown in Fig. 1 a drum 17 carrying nine helically wound wires 18 is mounted on a shaft 6 rotated by a motor 11 and driving at a reduced speed through gears 8, 9 the shaft 5 of a feed roller for the record sheet 19. The printing hammers 27, equal in number to that of the columns, cooperate with the spiral printing members 18 so that each blade is horizontally traversed nine times by the spiral assembly during a revolution of the cylinder 17, seven traversals being used for' character formation and two traversals allowing vertical spacing between the characters in the columns. The hammer members 27 are mounted in guide members 28, 30 and are biased towards the inoperative position by spring teeth 32 of a comb member mounted in a support 33 and in engagement with projections 45. The members 27 are secured by an insulating cement to clutch bands 35 extending around a sector of a continuously rotating drum 22 and are anchored by wires 37 to a support member 39 having clamping blocks 49 held by metal studs 47 engaging sockets carrying input conductors 51. The drum 22, which is of conductive material, has a layer 23 of semi-conducting material, and a pulse applied over a conductor 51 causes the band to be electrostatically attracted towards and gripped by the cylinder 22 so that the associated hammer 27 is impelled towards the printing cylinder 17. The impulses for effecting the printing are derived from pick-up heads 15 associated with circular sections of a drum 13 equal to the total number of letters, numerals and symbols, and each section has peripheral magnetizations corresponding to the impulses appropriate to the shape of the character. Circuit arrangement, Figs. 6, 7. The character signals from the drum 13 are simultaneously fed from the pick-up heads 15 to amplifiers 102 and over leads 104 to a switching matrix 105 to the input of which are applied coded signals, for example 7-unit code combinations on conductors 113, to select the characters for the various channels. The input character code signal produces from a translating device 115, forming part of the matrix 105, a pulse on a lead 117, 118-122 corresponding to the required character so that an associated "AND" circuit 123 can pass the pulses coming over a conductor 104 and corresponding to the selected character to an "OR" circuit 125 from which the pulses are applied over a conductor 108 to an associated amplifier circuit of the assembly 110 and to the clutch controlling the printing hammer 27 of the appropriate channel or column. The matrix assembly shown in Fig. 7 will be multipled according to the number of columns to be printed.