IE37985L - Printing machine. - Google Patents

Abstract

1392010 Reciprocating electric motors BELL PUNCH CO Ltd 17 Aug 1973 [18 Aug 1972 17 Nov 1972] 38759/72 and 53193/72 Heading H2A [Also in Division B6] In a printing machine in which a print head 36 moves relatively to a sheet when printing on the sheet, the head is moved by a drive mechanism 10 which comprises means e.g. electrical coils 22 for providing a magnetic field normal to the longitudinal axis of an elongated member, e.g. a mild steel bar 14, upon which is slidably mounted for movement parallel to the axis of the member on electrical conductor, e.g. a coil 32, upon which the print head is secured and which coil 32 is arranged to conduct electric current in a direction which is normal to both the axis and the magnetic field, and there is provided an electric circuit for supplying current to the coil 32 and/or the coils 22 so that the coil 32 moves longitudinally of the bar 14. As shown, the circuit to the coils 22 comprises a smoothing 24 and rectifier bridge 26 connected to an A.C. mains, whilst that to the coil 32 includes a step-down transformer 44 and a control circuit 40 while input 41 is connected to position control circuitry which causes the control circuit to generate a waveform whose shape determines the speed and direction of the head reciprocation; other circuits drive the sheet to be printed. Alternatively, these two supply circuits may be connected respectively, to the other coils 32, 22. The former 30 of coil 32 has on its cheeks shock-absorbing material 34. In other embodiments, the head and moving coil assembly are slidably mounted on rollers, and the mechanism is of tubular configuration. Position control may also be effected by a sensor comprising a stationary non-magnetic tape (52<SP>1</SP>), Fig. 4, having seven lines of perforations for co-operation with seven light-emitting diodes (56) and photo-electric diodes (58), Fig. 6, carried by the moving coil. [GB1392010A]