GB878495A - Type printing from code signals - Google Patents

Abstract

878,495. Selective printing. NORMAN, W. E. Dec. 22, 1959 [Dec. 31, 1958; Feb. 2, 1959], Nos. 38554/58 and 3691/59. Class 100(4) Selective printing apparatus controlled by successive signals in which relative movement between a character bearing endless belt or band and a printing station positions each character to be printed successively at the printing station is arranged so that the relative movement between the printing of two successive characters is equal to the shortest distance between them measured along the belt. A character bearing band TR passing over pulleys 3, 4 can be driven in either direction by being clutched by a clutch CLR or CLL to oppositely rotating flexible drives 9, 10 of a motor M. Printing is effected by a hammer 12 when a character is correctly positioned while the band TR is being traversed at a constant speed along a platen 1. The band TR is inked by rollers 15 operated by solenoids 16. The arrangement is such that after printing of a character the band TR is moved to position the next character selected in the direction required to give it the shortest movement the control being effected by electric circuits receiving signals from a punched or magnetic tape or a computer or teleprinter or like source and by signals derived from photo-cells P1, 2, 3, as windows W pass a lamp Z. Photo-cell P3 is a homing device while the impulses derived from P1 and P2 drive a counting tube in either direction according to the direction in which the windows W are moving. The appropriate clutch CLR, CLL is actuated to drive the belt TR in the required direction for the next character by comparing the potential significance of each signal with that of the previous signal and of a constant reference potential. When coincidence between the character signal and the counting tube signal indicates that the selected character is in the printing position the actuating clutch CLR or CLL is disengaged and breaks BL, BR are applied to stop the belt. The hammer 12 is now actuated when wipers wipe as the band moves along the platen 1 indicate that the correct spacing of the character has been achieved. In a preferred embodiment two bands TR are provided which constantly move from the ends of the platen to the centre and back and print alternately during their left to right movement. Printing may be effected by projecting a form of radiant energy through cut-out portions on the band so that said energy is transmitted in the form of a character on to suitable sensitized paper. The second Provisional Specification shows other embodiments including one in which a separate band is provided for each character space and printing of the characters of a whole line can be effected simultaneously.