Patent GB-821592-A (GB)
Title: Improvements relating to photographic type composing machines
IPC: B41B21/34
Filed: 1957-09-25
Abstract: 821,592. Photographic type-composing. MERGENTHALER LINOTYPE CO. Sept. 25, 1957 (Oct. 8, 1956], No. 30053/57. Class 98(1) A photographic type-composing machine, having a fount of characters which are selectively imaged at a photographing station, a film on which lines of characters are recorded, and means responsive to signals to advance the film after the recording of a line to present unexposed films at the photographing station ready for the next line, is characterized in that the film has electrically conducting reference marks on the margin, and electrical means co-operate with the reference marks to detect the advance or non- advance of the film. As shown in Fig. 1, lines of characters are recorded in areas 11 on the film 10, and perforations 12 are formed at the ends of the lines after exposure. Spaced reference marks 13 are formed of electrically conducting material on the margin of the film, as by printing. Each mark 13 has a base portion 14 with finger-like projections 15, spaced apart by their own width (e.g. 0.06 ins.). The spacing between marks 13 is the same. Three contact members 20, 25, 27 mounted on an insulating bracket 16 (see also Fig. 2) consist of leaf springs carrying rollers 21, 54, 30 pressed into contact with the marks, and are connected electrically to conductors 23, 26, 28. The outer contact members 22, 27, bearing rollers 21, 30 opposite each other, are connected through conductors 23, 28 to a triode amplifier 31, Fig. 3, which is conducting except when roller 21 rests on a projection 15. In this case, contacts 22, 27 are bridged by the conducting mark 13, and the normally non-conducting amplifier triode is allowed to conduct. A "flip-flop" circuit 32 consists of a normally non-conducting valve 33, and a valve 34 normally conducting to energize a relay coil K connected in its anode circuit. When an end-of-line signal is given to initiate the preparation of the machine for the projection of a new line of characters, a negative pulse is passed along a line 35 to the circuit 32, to cut off valve 34 and therefore to de-energize coil K. This causes the contacts K1, K2 to return to the positions shown in Fig. 4, completing a circuit to charge a capacitor 36. If, in response to the end-of-line signal, the film 10 is advanced one step, contact roller 21 engages the non-conducting film between the strips 15. Whether contact roller 30 remains in contact with the mark 13, or rests on the film between the marks, the circuit through contacts 23, 28 and the mark 13 is broken, so that the amplifier 31 conducts and a positive voltage pulse is sent through wire 37, rectifier 40 and wire 41 to "flip-flop" circuit 32, by way of a pulse-shaping circuit 43 if necessary, to restore the "flip-flop" circuit to its previous condition, so that valve 34 conducts again and coil K is energized. As contacts K1 separate and contacts K2 close, capacitor 36 discharges through a relay coil L, which closes contacts L1 to close a holding circuit for relay L, and contacts L2 shown in Fig. 5. Contacts L2 form part of a circuit by which a relay coil BCC can be energized to operate the machine in the manner described in Specification 801,481. Energization of coil BCC also opens contacts BCC2 (Fig. 4) after a time delay to de-energize relay coil L. The circuits are thus ready for another operation. If, however, the film 10 had failed to move, relays K, L would have remained inoperative, contacts L2 would not have closed, and the relay coil BCC could not have been energized to operate the machine. At the next film movement, contact roller 21 encounters a strip 15 and contact roller 30 either remains in contact with a mark 13 or encounters the next one, so that the circuit through the contacts is restored. Thus amplifier 31 conducts, producing a negative pulse which cannot pass the rectifier 40. It passes instead to phase inverter 45, producing a positive pulse which passes via rectifier 50 and pulse shaper 43 (if any) to the "flip-flop" circuit 32. From then on the action of the circuits is as described above. The roller contacts 54, 30 are connected through conductors 26, 28 to an amplifier 55 (Fig. 6), which conducts when both contact rollers rest on the same mark 13. When, due to the film advance, the contact 54 leaves mark 13, the amplifier 55 becomes non-conducting and produces a positive pulse, which has no effect. When the circuit is re-established, however, by the contact 30 coming into contact with the mark 13 on which contact 54 now rests, a negative pulse is produced, and this is passed, via a pulse shaping circuit 57 if required, to a "flip-flop" circuit 51 which consists of a normally non-conducting valve 53 and a normally conducting valve 52. The negative pulse causes circuit 51 to "turn over" so that valve 53 conducts, energizing a relay coil M in its anode circuit and operating contacts M1 in the circuit shown in Fig. 7. Closure of contacts M1 energizes stepping switch coil N and moves the stepping switch brush 60 to its next contact 61. Further operation steps brush 60 along the circularlyarranged contacts, until the 25th contact 64 is reached. This contact is connected to a coil 65 whereby a counter is actuated, and also through a rectifier 66 and stepping switch interrupter contact 67 to the coil N, which step brush 60 to the 26th contact 63 and opens contact 67. The next operation moves the brush to the first contact 62, so that the circuit is ready to operate again as described. The counter thus advances one digit for every 25 marks 13 which pass the contacts 54, 30; and with the dimensions given above this corresponds to a distance of one foot, so that the counter shows the number of feet of film which have passed through the photographing station. In modifications, the conducting marks and co-operating contacts can be replaced by notches or perforations in the film controlling mechanical switches. Besides preventing operation of the machine should the film fail to move, the safety circuits may also operate a visual indicator or alarm. Specifications 752,210, 754,648 [Group XVI] and 801,481 also are referred to.