Patent GB-967625-A (GB)
Title: Improvements in and relating to printers
IPC: G06K15/10
Filed: 1960-11-18
Abstract: 967,625. Selective printing. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 18, 1960 [Nov. 19, 1959], No. 39677/60. Heading B6F. [Also in Division H4] A printer in which the printed characters are formed by a plurality of dots suitably disposed on a print-receiving web by a plurality of print-impressing elements arranged in a row and in which the web is moved relative to the elements which can be impelled towards the paper, employs an individual electrostatic clutch arrangement to drive each element into contact with the web, and includes a code translator adapted to receive character-representing data signals and to generate a fixed number of groups of data bits for each charactor received, each data bit in a group being assigned to a corresponding one of said elements, and means are included to transmit corresponding groups of bits of each character in a line of characters to be printed to the impelling means in parallel, to drive selected ones of the row of elements in response thereto, the groups of said fixed number of groups of data bits being applied to the impelling means in sequence to print a line of complete characters. Data from a computer in a 6-unit binary code is converted to a 35-element code for printing the characters from a 7 by 5 dot matrix. For a line of 120 characters 600 printing elements are employed in a row, with seven sequential operations of the row of elements for printing a line of characters. The record sheet 100, Fig. 1, is fed continuously by sprocket 101 past a guiding or printing head 129 for the sets of elements associated with four clutch drums 124 operating successive groups of five pins to provide increased spacing of the clutch bands 123 on the individual drums. As shown in Fig. 2, the print-impressing members 105 (pins) are carried in spring-biased holders 119 attached to associated conductive bands 123 embracing the clutch drums 124 which are made of semiconductive material. The drums are maintained at earth potential and printing is effected by applying voltage pulses to the conductive bands which are caused to adhere by electro-adhesion force. The staggering or separation of the successive groups of five pins for the four drums is indicated in Fig. 3 (not shown). An alternative construction utilizing print hammers is described with reference to Figs. 5 and 6 (not shown). An apertured disc 107 on the shaft of the sprocket 108 in conjunction with a light-source 108 and photo-electric cell 109 provides timing pulses to control the seven successive indications of the row of pins for printing a line of characters, also to provide spacing between the lines of print, and additionally to control the computer 112 to provide a fresh set of data for application to the code converter 113 for the storage circuits 114 and 115 after the previous line of characters has been printed. When the code of a line of characters has been stored in the circuit 115, print latch circuits are set selectively and apply pulses to the members associated with the clutch drums so that the appropriate printing pins 105 are simultaneously impelled against the paper 100, this operation being repeated seven times to form the line of characters. Code converting arrangement, Figs. 7, 8, 8a, 9 and 10 (not shown). A basic 6-unit code is converted by an arrangement detecting the elements in the six positions and by arrangements examining the elements in a twopositions zone and the remaining four-positions zone to provide outputs on two individual leads which, in a further circuit provide an output on an individual connection corresponding to a letter, numeral or sign. Each of these individual connections is taken to a matrix connector arrangement which provides connections in seven rows to produce the dots, for the formation of the character in the 5 by 7 matrix. Buffer storage arrangement, Fig. 12. The pulses from the converter are passed to a buffer storage 115 comprising 120 sets of 35 cores, each set arranged in a plane 179, and the 120 core planes are arranged in four blocks 164 . . . 167, each being thirty planes deep. The successive characters are distributed to the blocks in the order 164, 165, 166, 167, 164, 165 &c. by a four-position " closed ring " switch 175 with connections 168 . . . 171, and a thirty-position switch 183 with outputs 172 which selects succession core planes. The switch 175 is stepped by each character from the computer 112 and each time it reaches position 4 it passes a pulse to the 30-position switch 183. When switches 175 and 183 are in position 4 and 30 respectively, pulses through an " AND " gate 189 control the computer to cut off data transmission until the printing operation has been effected, and the switch 183 cannot return to position 1 until a reset pulse is received over the lead 184. Reading-out Buffer Storage, Fig. 13. For the reading-out operation of the store 115, the three-dimensional assembly of cores is effectively divided into places in three dimensions. There are fourteen planes of cores from left to right, indicated by 195, ten horizontal planes from top to bottom indicated by reference 196 and thirty vertical planes of cores from front to back, as indicated by reference 197, and to effect printing of the first row of dots it is necessary to read the first five vertical cores of the four blocks in succession commencing with the first vertical plane, and in succession for the remaining twenty-nine vertical planes. For the second row of dots, the second vertical plane of 5 cores is read out for the four blocks out of the thirty front to rear planes and so on until the seventh column of five cores for the four blocks and for the thirty planes front-torear have been read out-to complete the line of printed characters. In the reading out operation, pulses are applied to sense the ten horizontal rows of cores simultaneously and the thirty vertical planes from front to back are selected in turn by the 30-position switching unit 183 so that from ten output amplifiers 198 pulses pass over lines 221 to latching members. The fourteen vertical planes which determine the dots for the seven rows are scanned in succession by pulses from amplifier members 214 controlled by switching circuit 215 which are controlled conjointly by a leftright trigger circuit 217 and pulses from a 10-position stepping circuit 202 stepped by pulses from the chopper disc 107, Fig. 1, and associated circuit 200, the arrangement being that with member 202 in position 1 the first and eighth vertical planes are scanned in succession, followed by the second and ninth vertical planes, until in position 7 the seventh and fourteenth vertical planes are scanned. At position 7, a pulse is passed over line 194 to indicate that the printing operation has been initiated so that the computer can provide further data to be fed to the buffer storage. The stepping of the circuit from position 7 to position 10 provides partial spacing between the lines of print. Also, the printing-complete pulse through gates 226, 209 restores the 30- position circuit 183 for loading the storage 115 with a fresh line of characters from the computer. Printing operation.-The pulses from the connections 221, Fig. 13, are distributed to appropriate latching circuits individually associated with clutch hands by means of 600 gate stages controlled by pulses from 30- position switching unit 183 and trigger circuit 217, and a short control pulse for each row of dots provides simultaneous operation of the clutch members to actuate the appropriate pin members to print the corresponding dots, the cessation of the control pulse operating a trigger to reset the latch circuits to respond to the pulse for the subsequent complete line of dots. The outputs of the latches are connected to the appropriate clutch member associated with the four drums 124 to reproduce the characters in the correct sequence.