| 摘要 |
1,164,695. Selective printing. INTERNATIONAL COMPUTERS Ltd. 8 March, 1967, No. 10793/67. Heading B6F. Apparatus for feeding of a record in a selective printer to a particular printing line includes a perforated tape 10, Fig. 1, whose perforations 23 which are representative of a printing line are scanned by a pair of spaced photoelectric sensing stations 58, 59 co-operating with a reticulated lens block 19, provided with two lenses 20, to generate output signals which are applied selectively to one or the other of amplifiers 60, 61 for energization of a fast or slow speed drive for a record 25, Fig. 2, depending on the number of blank lines between the respective printing lines. The record 25 is supported on a platen 24, which is driven by a pulley and belt drive 27, 28, 29 from a shaft 30 driven in turn by a slow drive 34 or a fast drive 42 through selectively actuatable magnetic clutches 37, 40, the drives being connected to the respective ends of a shaft 35 associated with a drive motor 36. Mounted on the shaft 30 is a magnetic brake 49 and a pair of pulse generators 50 in the form of toothed wheels generating pulses representative of line spacing positions and associated with pick-up heads 51 whose pulses are applied to amplifiers 53. The output of the amplifiers is applied to a motor 13, Fig. 1, via a line 55 for synchronous feeding of the program tape with the record 25. In operation the selective printer 63, Fig. 4, produces a record movement signal over a line 64 which signal is applied to an OR gate 71 setting flip-flop 68 for energization of a coil 65 of slow speed clutch 37 and resetting of flipflops 69, 70 of fast speed clutch coil 66 and magnetic brake coil 67. The signal further resets the counter 72, which produces an output signal every three line counts supplied to it by the pulse generators 50 over a line 55 and, sets simultaneously a flip-flop 75 to condition an AND gate 76 which passes a signal to the counter 72 every time a signal is passed over the line 55. With the record being fed at a slow speed and the pulse generators applying successive signals to the counter 72, the latter emits an output signal every three counts. The signal is applied, on the one hand, to the input of flip-flop 69 of the fast speed clutch coil 66 to feed the record 25 at the fast speed and, on the other hand, to the OR gate 73 to reset the flip-flop 68 of the slow speed clutch coil 65. When the sensing station 59 senses a perforation 23 in the program tape 10, during the fast record feed movement, then the output of the amplifier 61 is applied, on the one hand, to the OR gate 71 to set the flip-flop 68 of the slow speed clutch coil 65 to reduce the record speed and, on the other hand, to the flip-flop 75 to reset the latter, the counter 72 and flip-flops 69, 70 being reset by the output from the OR gate 71. The same perforation is then sensed by the sensing station 58 to produce an output signal which is applied to the amplifier 60 whose output, on coincidence with signals in line 55, actuates an AND gate 74, which resets the flipflop 68 of the slow speed clutch coil 65 through the OR gate 73 and sets the flip-flop 70 of the magnetic brake coil 67 to energize the brake 49, Fig. 2, and position the record 25 at the selected printing position. The record 25 is always started at slow speed so that when the blank feed exceeds six lines the record is then fed at a high speed, which is again reduced before the record is stopped by the magnetic brake 49. In another embodiment in which the feed of the record is increased between successive printing lines the lens block 19 is replaced by a block having three lenses (81, Fig. 5) and the third sensing station (80) performs partially the function of the counter 72 which is dispensed with. The main effect, however, is obtained by the fact that the sensing stations are spaced from one another at intervals of two instead of three line spaces so that fast speed feeding is resorted immediately after the slow speed start providing, of course, that no perforation has been sensed meanwhile by any one of the three stations. |
