1323432 Control of printers CANON KK 10 July 1970 [12 July 1969] 33684/70 Heading G4H [Also in Division B6] In an electrographic printer where a whole line of characters is built up by several scans of an electrode across a recording medium, the movement of the electrode generates, photoelectrically or magnetically, trains of pulses which indicate the displacement of the electrode across and down the recording medium. As shown in Fig. 2 a character, the numeral "2" is synthesized from seven horizontal scans 01 to 07 during each of which the electrode is selectively energized in one or more of the time periods t 0 -t 1 ...t 4 -t 5 to create marks such as 118, 119. Four electrodes are carried on a rotating disc 13 each one making one of the scan lines across the recording medium 21 which is moved in steps. An apertured disc 14 carried on the rotating shaft 11 carrying the disc 13 generates by apertures 30 and photo-cell 34 one pulse for each of the 18 character positions across the recording medium and by apertures 31 and photo-cell 35 one pulse for each scan line. The pulses are fed to a control unit 39 which also receives from a computer 40 numerical data to be printed. Within the control unit a counter generates for each character pulse signals defining the time periods t 0 to t 5 (Fig. 10), plus t 6 for a decimal point position not shown in Fig. 10, and from which a logic arrangement of gates (Fig. 5, not shown) generates timing signals corresponding to all the possible lengths of marks, such as those of Fig. 10, that could be used to synthesize a character. According to the character to be printed and the line of scan (Fig. 7, not shown) particular ones of these timing signals are selected (Fig. 8, not shown) and fed to the electrodes. The character information for a line has to be presented successively for each of the seven lines of scan of a single line of print.