GB1382332A - Electronic character printer - Google Patents

Abstract

1382332 Printers PRINTER TECHNOLOGY Inc 17 Jan 1972 [15 Jan 1971] 2105/72 Heading G4H [Also in Division B6] An electronic character printer has a print drum movable along the print line and rotatable about an axis parallel thereto, the drum bearing a multiplicity of character elements arranged along helical paths about its circumference and forming at least one character set extending about substantially the entire circumference of the drum, the set including a pair of axiallyoffset character groups, each extending approximately half of the circumference, a plurality of print hammers being movable along the print line in synchronism with the print drum, there being one hammer per group of character elements, the hammers being actuated in response to electronic input signals indicating the matter to be printed and to means indicating the relationship between the hammers and the character elements. Further mechanical details (Fig. 1).-A motor 44 rotates a hexagonal shaft 12 and a worm shaft 14, continuously, the print drum 20 rotating with the shaft 12 on which it can slide. To print a line, a hammer carriage 25 is coupled to worm shaft 14 to be moved along the line, the drum 20 being moved along as well due to yoke 32 linked by cable 34 to carriage 25. Six hammers 54 correspond respectively to six groups of character elements A1, B1, A2, B2, A3, B3, each group occupying 180 degrees and forming half the fount (which is thus repeated three times), so only one third of the columns on the paper 50 can be printed in by a given pair of groups. At the end of the line, the carriage 25 is uncoupled from worm shaft 14 and is returned by a spring 40. An ink ribbon 55 is provided, or an ink roller for the drum could be used. Electrical details (Fig. 6).-A computer CPU supplies three characters at a time to buffer registers A, B, C, respectively, the data being shifted to registers 10-12, then to registers 7-9 after one revolution of the drum, then to registers 4-6 after another revolution, registers 4, 5 feeding registers 1, 2 after a further revolution, except that a character is deleted once it has been printed. Three comparators COMP 1, 2, 3 each receive the contents of one of the registers in one half of the revolution and of another in the other half, as indicated by the connections in Fig. 6. The other comparand is a count at CTR of clock pulses sensed magnetically from a wheel 18 (Fig. 1) on the hexagonal shaft 12 (or an optical code disc can be used). The comparators COMP 1, 2, 3 control the hammers for the groups A3, B1, A2, B3, A1, B2 as shown. Modifications.-A single pair of groups as above can be provided on the drum, or two, or four.