| 摘要 |
893,845. Selective printing. BURROUGHS CORPORATION. Feb. 25, 1959 [May 9, 1958], No. 6574/59. Class 100(4) [Also in Groups XL(a) and XL(b)] An electrographic recording apparatus comprises a line length of printing heads 10, Fig. 3, each having print electrodes 52 and a plurality of initiating electrodes 54 driven by pulse generators 76, 66 and 66e respectively, the print pulse generator 76 applying a print pulse to a print electrode 52 associated with a fixed group of initiating electrodes so that print charges are applied to a record web at element positions where both a print pulse and an initiating pulse is present. The input signals may be sensed from a tape or received in a decoder 70 as pulses, e.g. a 6-bit binary code or a 5-unit teleprinter code. The output of decoder 70 is connected to an encoder 68 which operates the initiating pulse generators 66a-66e according to the shape of the character to be printed. The initiating electrodes in the whole line length of print heads 10 are energized at the same time but since it is necessary for both initiating and print electrodes at any point to be energized simultaneously to cause a discharge, only one head effects printing. This is determined by a stepping switch 78 which connects the print pulse generator 76 to each print head in turn. After the charges are established in a polythene dielectric layer on the web 26, ink powder is deposited on the charges at 56, surplus ink powder shaken off at 57 and the ink attracted to the charged areas is forced into intimate contact with the plastic layer by calendering roll 62. Specifications 784,450, 893,844 and 893,846 are referred to.
|
