Patent GB-977563-A (GB)
Title: Paper feed control apparatus for a printer
IPC: B41J11/51
Filed: 1963-03-13
Abstract: 977,563. Selective printers. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 13, 1963 [March 30, 1962], No. 9866/63. Heading B6F. [Also in Division G4] Type-band actions; paper strip, web feeding, clamping and guiding arrangements.-An endless steel type-band printer comprises a first drive means 26, 27, 32, Fig. 1, for advancing a continuous form 25 past a printing position and a plurality of second drive means 35-1 . . . 35-8, one or more of which is or are arranged for advancing one or more of a plurality of continuous webs 36, 37, 38 past the printing position and includes a selecting means for rendering effective either the first or second drive means. The continuous form 25 is selectively advanced by a pair of tractor assemblies 26, 27 moved in synchronism through a shaft 31 by an hydraulic drive mechanism 32 including an hydraulic motor (not shown) which is operated at a slow speed by one hydraulic pump and at a fast speed by concomitant operation of this and a second hydraulic pump. A control valve arrangement (not shown) operated by a plurality of magnets 100, 101, 102, 103, Fig. 3, selectively controls the output of the pumps and input of the motor for the desired speed of operation. The plurality of tape drive assemblies 35-1 to 35-8 are adapted for individually advancing a single tape width such as 37 or 38 or pairs of the tape drives are adapted for advancing tapes of double width such as 36. Each tape drive assembly comprises an electromagnet 50, Fig. 2, having a plunger 51, which operates a pivotally mounted arm 52 to raise an arm 58 carrying at its end a pivotal arm 65 with a cylindrical rubber element 66, which presses the tape 36 against a blade 67, Fig. 1, so as to clamp the tape and advance it incrementally. A pair of paper guides 70, 71 is provided to guide the tape during the advancing motion. A second pivotally mounted arm 72 carries a cylindrical rubber element 73, which clamps the tape against the guide element 71 during re-energization of the magnet to prevent reverse movement of the tape. Long feeds, feeding to a particular line and like feed-roller rotation.-The printer is operated in either a " forms mode " of operation or a " multiple tape listing mode" of operation, whereby in the former case only the continuous form 25, Fig. 1, will be advanced and the latter case only a selected tape will be advanced past the printing position. An operator sets the forms or tapes for the desired mode of operation. In the " forms mode " the forms may " space " i.e. move vertically by a distance of one line or " skip," i.e., move several lines, between printing cycles. Spacing is controlled by appropriate energization of the slow speed start and stop magnets 100, 101, Fig. 3, respectively and skipping is controlled by appropriate energization of high-speed start and stop magnets 102, 103, respectively. During skip operations the forms advancing mechanism is controlled by a tape assembly 40, including a paper tape 41, having apertures 42 and a set of brushes 48 cooperating with the apertures and a plate 46 to establish a control circuit. (a) Forms mode of operation.-For forms mode of operation a switch 140, Fig. 3, having arms 143, 144, is positioned as shown in solid lines, to supply a positive potential via the input terminal 105 to one of the inputs of AND gates 109, 114, 135. As the input terminal 104 of the AND gate 109 receives the end of print signal it causes a single shot multivibrator 111 to set the carriage interlock latch 112 whose ON output 113 sets the AND gate 114 which energizes the magnet driver 115, which in turn will energize the start magnet 100 to operate the forms drive mechanism and the form will be advanced one line space. The single shot 111 also sets another single shot 125 which through an inverter output 126 and an OR gate 156 energizes single shots 127 and 128, to reset the carriage interlock latch 112 and to prevent processing in the data processing unit by setting the OR gate 130, respectively. The interlock latch output 113 is also connected to an OR gate 150, connected to the print scanning circuit 132 to prevent a printing cycle during forms advance. Following resetting of the carriage interlock latch 112 by the single shot 127 the OFF output of the latch 112 energizes magnet driver 118 through an OR gate 117 and the magnet energizes the low speed stop magnet 101. Form skipping before or after printing is initiated by AND gates 109c and 109b, respectively, and operating signals from latches 179, 180, Fig. 4, the latter being applied to the input terminal 108, causing the AND gate 135 to set the carriage interlock 112 and the high-speed skip trigger 136, which through the magnet driver 137 energizes the start magnet 102. When the brushes 48 associated with the tape control unit 40 signal decimal code that the required amount of skip has taken place the compare circuit 151, which receives one of its inputs from a character register via a decimalto-binary register 152, produces an output signal 155, which resets the carriage interlock latch 112 and the trigger 136 whose OFF output energizes a high-speed stop magnet 103. (b) Multiple tape listing mode of operation.- In this mode of operation the switch 140, Fig. 3, is placed in its broken line position to disable the control circuit for the forms mode of operation. The multiple tape listing mode of operation is controlled by latches 181 ... 184, Fig. 4, which are set, respectively, by signals on the " 1," " 2," " 4 " and " 8 " output lines from the register 172 through, AND gates 188 ... 189, and the latches are reset by an AND gate 195. The latches have ON and OFF output lines 200 ... 203, and 205 ... 208, respectively, connected to eight AND gates 210 ... 217, for the purpose of translating the binary coded decimal number in the latches 181 ... 184 into decimal form for selective energization of one or more of a plurality of tape control latches 220 . . . 227, which is or are set when a conditioning signal is received on the line 231. These latches in conjunction with a pulse on line 260 condition appropriate ones of a plurality of AND gates 250 ... 257, which through magnet drivers 240 ... 247, activate the corresponding tape drive units 31-1 . . . 31-8. The pulse on the line 260 is also fed to an inverter 270 and the inverted pulse to a single shot multivibrator 271, the latter producing an output signal on the line 272 fed through an OR gate 273 to reset the tape latches 220 ... 227.