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Ink Printer Drop Deflection Programmable Waveform Synthesizer for Charge Compensation

IP.com Disclosure Number: IPCOM000081112D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 62K

Publishing Venue

IBM

Related People

Bengds, EE: AUTHOR [+3]

Abstract

This system provides a digital means of synthesizing a nonlinear waveform, which is required for compensation of charge interaction in ink jet printing. The diagram in Fig. 1 shows an implementation of this method using either a random-access memory or a read-only memory.

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Ink Printer Drop Deflection Programmable Waveform Synthesizer for Charge Compensation

This system provides a digital means of synthesizing a nonlinear waveform, which is required for compensation of charge interaction in ink jet printing. The diagram in Fig. 1 shows an implementation of this method using either a random- access memory or a read-only memory.

The Sweet principle of drop deflection printing requires a method of charge interaction compensation. The charge interaction compensation can be implemented by modifying the digital value supplied to a digital-to-analog (D/A) converter according to an algorithm, which is a function of the drop sequence to be printed and also the absolute drop position to be printed. The number of digital values generated in this way increases in binary fashion, due to the requirement that all combinations of bits be taken into account for effective compensation.

The waveform synthesizer was made programmable, in order to provide flexibility in modifying empirically the coefficients in the compensation algorithm. As the algorithm coefficients are changed, a new set of digital values is calculated offline and then loaded into the random-access memory. A requirement for one printer application was that a minimum of 5120 values in the synthesized waveform had to be resolved within one part in 1024. Also, the implemented hardware was required to supply the compensated waveform to three print jets simultaneously. This requirement was met by time sharing the synthesizer via a multiplexer, in such a way that the proper data is supplied to each print let nozzle at the correct time. The application requires an implementation which has a matrix resolution o...