GB1435618A - Ink drop printing system - Google Patents

Abstract

1435618 Ink drop printers DICK CO AB 29 Oct 1973 [13 Dec 1972] 50142/73 Heading G4H An ink-drop printer incorporates means for charging the drops by ionic bombardment. The drops 20, 22 . . . are produced by a vibrating nozzle 10 and directed past a photo-cell 46 (which produces a pulse for each passing drop) to deflecting plates 90, 92 one of which contains apertures 50-58 through which ions from a source 60 can be selectively passed. The passage of ions is controlled by conductive layers 82 around the apertures and separated from plate 92 by an insulator; the layers are controlled by the outputs from shift registers 72-80. Video signals 86 are converted at 84 into charge signals for each drop; each signal is converted at 85 into a 5-bit signal and applied to the registers. If, for example, a drop is to acquire 3 units of charge then the signal is 11100, the bits being entered into the 1st, 2nd . . . stages of the registers respectively. The pulses from 46 are delayed to allow the drops to arrive at the apertures and used to shift the registers: in the present example, the sequential "1" outputs from 72, 74 and 76 apply voltages to layers 82 so that they pass ions to the drop as it passes over apertures 50, 52 and 54. The drop is thus bombarded three times by ions from 60. For printing characters, the pulses are also passed to a counter 88 whose output controls the release of the appropriate number of signals from video source 86 to control source 84. The counter may be omitted when curves instead of characters are to be printed. In an alternative embodiment (Fig. 3, not shown) only one aperture is used, the conductive layer 82 then receiving a variable voltage direct from source 84.