Patent GB-1267124-A (GB)
IPC: B41J1/48
Filed: 1970-04-28
Abstract: 1,267,124. Selective printing. CITIZEN WATCH CO. Ltd. 28 April, 1970 [1 May, 1969; 7 May, 1969; 28 May, 1969], No. 20405/70. Heading B6F. Type-wheel machines; type-wheel construction, Fig. 4a.-A helical spring 76 is mounted in each of the type-wheels 62 so that a portion 62<1>a of each type-wheel is biased into contact with an operation bar 75. Rotation of the operation bar 75 about axis 57 allows all the typewheels to rotate in unison until such time as each type-wheel is selectively latched by the tooth 82a of a selection member 82 engaging one of the teeth of a ratchet 62c formed on each type-wheel. The plurality of selection members 82 are operated by a plurality of bistable levers 84, selectively pivoted by electromagnets 73 under the control of a coded input and a detector coil 63, detecting the angular position of the type-wheels. In the particular embodiment described, the shaft 57 completes a revolution for each line of print. The pair of cams 61a fixed to the shaft 57, pivot spring-loaded levers 77 carrying a selection clear bar 79, which bar moves downwards to release the selection members 82, thereby allowing the type-wheels to complete the single revolution under the action of the helical springs 76. At the same time, bi-stable levers 84 are returned to their initial position. Platen-impression.-The platen 65 swings for impression under the control of cams 55. In an alternative embodiment (Fig. 46), instead of the platen 65 being journalled between a pair of levers 56, as in Fig. 4a, the shaft (65a) of the platen is held in a notch in each lever 56 by a spring-loaded bell-crank lever (101). Zero suppression arrangements.-Two embodiments are described; the first (Figs. 5 and 6) in which the decimal point is an additional character carried by one or more of the typewheels; the second (Figs. 7 and 8) in which decimal point type-wheels are disposed in predetermined digit positions between adjacent type-wheels. In both embodiments, selection member discrimination levers (94) are arranged in opposed relation with respective selection members 82, and are operatively associated with each other by means of a bent lug (94b) formed on each of them. Web-feed (Fig. 10).-The web-supply roll (74) rests in a container (150) on a pair of rubber rollers (155) and a stripper blade (151a). The web is advanced below the stripper blade and is urged into contact with a feed roller (160) by a spring-loaded idler roller (161). The rollers (155 and 160) are driven intermittently by a Maltese Cross arrangement and a pulley system. A severing blade (167) is mounted on a pivoted lever arrangement so that when the blade is moved into the operational position, the idler roller (161) is moved away from the feed roller (160), so that the web may be freely withdrawn. Ink ribbon feed (Fig. 9).-The ink ribbon is advanced from one spool to the other by a ratchet mechanism driven by one of the impression cams 55, Fig. 4a. The ratchet mechanism includes a feed claw (117) which takes up one of two positions depending upon which spool is the take-up spool. A spool diameter detecting lever (72) is associated with each ribbon spool, and automatically reverses the drive when a spool is full.