GB1180372A - Slidable Print Head for a Printing Apparatus - Google Patents

Abstract

1,180,372. Selective printing. NATIONAL CASH REGISTER CO. 11 Nov., 1968 [12 March, 1968], No. 53278/68. Heading B6F. Letter-spacing; thermal printers.-A selective printer comprises a print head 44, Fig. 1, slidably supported on a bar 46, the print head being movable from a non-printing position to a printing position by rocking the bar 46, and being indexable along the bar 46 for letterspacing movement, both rocking and indexing movements being effected by a common member. The common member comprises a lever 66, Fig. 6, acted upon by a solenoid 76. Energization of the solenoid 76 causes counterclockwise pivoting of the lever 66, which acts to rock the bar 46 through a link 80, Fig. 6, and further links (82, 84, 90), Figs. 9, 10, not shown, so that the print head 44 assumes its printing position and an impression can be made. De-energization of the solenoid 76 permits a spring 70 to urge the lever 66 clockwise, whereby the print head returns to its non- printing position and is indexed one character space by means of a pawl 102 on the lever 66 acting on a ratchet wheel 96 to rotate a shaft 64 which carries a pulley 60, Fig. 1, around which passes a belt 54 which is keyed to the print head at 56. A pawl 108, which normally engages a second ratchet wheel 98 on the shaft 64 to prevent clockwise rotation thereof, is mounted on the lever 66 such that during letterspacing movement of the shaft 64 the pawl 108 is disengaged from the ratchet wheel 98. The mechanism is applied to a thermal printer of the kind having a five-by-seven array of selectively energizable resistive elements, to print on thermally sensitive paper. Carriage-return mechanism.-When the print head 44 reaches the end of a print line, a switch 122. Fig. 1, is closed thereby, so that a solenoid 124 and a motor 126 are energized. The solenoid acts to draw a plunger 128, Fig. 6, rightwardly so that a lever 130 pivots about a fastener 134. The lever 130 engages pins on pawls 102, 104 which normally prevent counterclockwise rotation of the ratchet wheel 96 to urge the pawls out of engagement therewith. Concurrently, a cable 144 connected to the lever 130 is relaxed, permitting a spring (146), Fig. 3, not shown, to urge a lever (148) to engage a clutch which drivingly connects the motor 126, Fig. 1, with a gear 156 to drive the shaft 64 and return the print head to the beginning of the line. The print head acts on a switch 168 at the beginning of the line, to de-energize the solenoid 124 and motor 126. Line-spacing.-Paper for receiving printed impressions is fed for line-spacing by pin wheels 172, 174, Fig. 1, by means of a solenoid 218 which acts on a pawl (208, Fig. 3) to rotate a ratchet wheel 198 keyed to the shaft 176 bearing the pin wheels 172, 174. Input arrangements.-The print head 44 is connected by a multiple conductor cable 246 to a terminal block 248, to which a computer or keyboard may be connected.