GB1323677A - Printing arrangements - Google Patents

Abstract

1323677 Printers D V G BERRY 5 Nov 1970 [9 Aug 1969] 39929/69 Heading G4H For control of a printer, the address of the required character on a carrier and an indication of the momentarily effective printing site position are used by a summer to calculate the required carrier position which is compared with the actual carrier position. A type band, bearing the font a plurality of times, carries the types along the print line and a second band is stepped to position a hammer at the different print sites along the line in turn, the distance between adjacent print sites being smaller than that between adjacent characters on the type band. The position on the type band of the character to be printed and the position of the hammer band, multiplied by factors representing the distances between adjacent print sites and between adjacent characters on the type band, are added, the sum being taken modulo a constant depending on the font size, to indicate the required position of the type band which is compared with the actual position to actuate the hammer on equality. Marks on the type band are sensed and counted to indicate the position of the type band, the counter being reset by a further mark for each repetition of the font, or a shaft digitizer could be used. The position of the hammer band is indicated by sensing and counting marks on the hammer band. In the calculation above, the parameters may be adjustable to allow for change in the spacing of hammerband (i.e. print) positions and of characters on the type band, and in the number of characters in the font. The character spacing as printed may depend on character width by varying hammer actuation time in accordance with stored character widths. Printing could alternatively be photographic (the type band holding photographic masters, printed by a light beam), or a plurality of hammers could be provided.