| 摘要 |
741,259. Printing-machines. HUEBNER CO. Oct. 27, 1953, No. 29649/53. Class 100 (2) In a printing-machine of the kind in which an inked image, carried on a printing cylinder 46 is transferred to print receiving material M in a printing zone by means of a high potential, unidirectional cyclically pulsating electrostatic field of force, the film of ink on the printing cylinder and the material M are charged, before entry into the printing zone, with unidirectional electrostatic charges of opposite polarity to assist the field of force in the printing zone to effect the transfer of the ink. The printing cylinder 46 is rotatably mounted and bears a relief, intaglio or planographic image inked, e.g. by rollers 48, 49. An electrode blade 47 mounted in a stationary insulating sleeve 12 inside cylinder 46 co-operates with a similar electrode 51 mounted inside a supporting cylinder 50 to provide the field of force in the printing zone. The material M for printing passes between cylinders 46, 50 but is subjected to substantially no pressure. A source of high-voltage direct-current 56, which may consist of a transformer and rectifier valves, has output wires 60, 61 and 62, 63 connected to reversing switches 70 and 90. A wire 76 from electrode 51 has a brush 75 bearing on a rotary switch or commutator 74 mounted on the shaft of a small motor 83. A brush 73 bearing on the other side of the switch 74 is connected to one pole of switch 70. The other pole of this switch is connected through an ammeter A (or its shorting switch 89) to the electrode 47. To stabilize the voltage applied between the electrodes 47, 51 condensers 78, 79 and resistances 80, 81 are connected between wires 71, 72. A wire 82 connects the centre points of the condensers and resistances. The applied voltage may be indicated on a voltmeter V. The speed of the motor 83 may be varied by a rheostat 86 to vary the number of pulses per second between the electrodes. Charging devices 52, 53 are applied to the surface of the printing cylinder and to the web. The device 52 is curved to mate with the surface of the cylinder and has a series of discharge teeth 54. It is connected by wires 104, 92 to one pole of switch 90. The other pole of switch 90 is connected through a rotary switch 94, driven by motor 95, to the charging device 53 applied to the material M. A similar stabilizing circuit is provided for the voltage between the devices 52, 53. By this means pulsating unidirectional potentials may be applied between the electrodes 47 and 51 and between the charging devices 52 and 53. The number of pulses per second may be varied by rheostats 86, 96 and the potentials may be varied by controls 64, 65 on the source 56. The reversing switches 70 and 90 may be ganged together for simultaneous operation. A steady potential may be applied between the devices 52, 53 by de-energizing motor 95 and turning switch 94 to the connecting position. Reference has been directed by the Comptroller to Specification 613,163.
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