GB1177184A - A Line Printer Paper Feed Control System - Google Patents

Abstract

1,177,184. Selective signalling. FUJITSU Ltd. 19 July, 1967 [20 July, 1966], No. 33238/67. Heading G4H. In a line printer paper feed control system, in order to avoid large starting and stopping forces which might tear the paper, two paper feeding speeds are used, a slow starting and stopping speed, and a feed speed, which is only used if the paper has to be fed sufficiently far, for the central position of the displacement. The system is controlled by eight-channel paper tape, Fig. 5, each channel corresponding to a specific line-format programme, and each punch hole indicating the number of the line on which printing is to occur. In prior systems the printing paper and programme tape have been advanced synchronously, each advance occurring after a line has been printed and continuing until the next hole in the operative channel on the tape is sensed. In the system described whilst one line is being printed the programmed tape is advanced independently of the printing paper until the next hole in the operative channel is sensed. As it advances the sprocket holes are sensed and the pulses produced entered into a control counter. When printing of the current line is complete, the printing paper is advanced and pulses are produced, one per line, and entered subtractively into the control counter until it reaches zero. The printing paper will then be in position for the next line of print. The speed of the printing paper is controlled by the control counter, and the arrangement is such that the paper is always started and stopped at the slow speed, but if it has to move sufficiently far, and this is determined by the content of the counter, then the speed is increased to the high speed for the central portion of the displacement.