Patent GB-1173635-A (GB)
Title: Printing Method and Apparatus.
IPC: B41J19/32
Filed: 1967-09-15
Abstract: 1,173,635. Selective printing. INTERNATIONAL BUSINESS MACHINES CORP. 15 Sept., 1967 [19 Sept., 1966], No. 42163/67. Heading B6F. [Also in Division G4] Differential spacing arrangements.-A method of printing on a document a line of characters using differential spacing comprises allocating to each character a number of width units in accordance with the width of the character, grouping the width units in accordance with the sequence of the line of characters into a plurality of groups, each group containing a plurality of width units, and performing sequence of different partial printing cycles equal in number to said plurality, for each printing cycle printing only those characters which start at a predetermined number of width units from the beginning of each group of width units, and locating the document said predetermined number of width units from a datum position. In the embodiment described, each group comprises five width units and the characters to be printed are allocated three, four or five width units according to their width. The line of characters to be printed is stored as coded representations in data processing equipment, together with data representative of the number of width units allocated to each character. With the document in a first position, a series of characters is printed, the position of each of these characters, expressed as a number of width units from a datum line located at the starting point of the first character on the line, being 5n where n is an integer. The document is then shifted, preferably by one width unit, and a second series of characters are printed, whose positions are 5n + 1 width units from the datum line. Three more such printing operations are undergone to complete the line. Pin feeds.-The document, in the form of a web, is fed by pin tractors 19A, 19B. The tractor 19B is fixed to a bar 30 slidably mounted on a fixed bar 32, and the tractor 19A is connected to a support 33 which is adjustably located on the bar 30 by a thumb screw 35 which engages holes 34 in the bar. A vernier screw adjustment 36 connects the tractor 19A to the support 33. The document is shifted after each partial printing cycle by a cam 41 acting on followers 37A, 37B, mounted on a lever 37 pivoted at 39 to an extension 38 of the fixed bar 32 and coupled at 40 to the sliding bar 30. The cam 41 may be rotated stepwise or continuously by a motor 43; in the former case the cam surface may be either a continuously sloping surface or a stepped surface, the motor 43 moving the cam so as to slide the bar 30 by a multiple of a width unit, whereas in the latter case the cam surface must be stepped, the motor rotating at such a speed as to traverse a portion of uniform radius in the time necessary to effect a partial printing cycle. Type case machines; hammer impression. arrangements.-Individual type elements (11), Fig. 1 (not shown), are movable in a continuous path on a stationary frame (12) and back impression hammers (60) are actuated by electromagnets (40) and spring-returned, as described in Specification 990,673. Each type element 130, Fig. 9, includes an anvil, the centre of which is located at a fixed distance X from a datum line at the left-hand side of each character, except five-width-unit characters such as w, wherein the centre of the anvil is one width unit further from the datum line. The type elements for five-width-unit characters are enlarged (Fig. 10, not shown) and the adjacent element partially cut away. The possibility of overlap of impressions is prevented by modifications in the electronic circuitry.