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Analog Print Head Driver Using Charge Coupled Device Technology

IP.com Disclosure Number: IPCOM000037238D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Sanford, JL: AUTHOR

Abstract

Disclosed is a system for driving multiple writing element print heads for serial or full width print engines. This system utilizes charge coupled device techniques for handling analog data for grey level printing, printing element uniformity compensation and delay correction for writing elements in multiple rows, thereby efficiently, in terms of silicon real estate, achieving complex functions not practical with analog and digital circuit techniques.

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Analog Print Head Driver Using Charge Coupled Device Technology

Disclosed is a system for driving multiple writing element print heads for serial or full width print engines. This system utilizes charge coupled device techniques for handling analog data for grey level printing, printing element uniformity compensation and delay correction for writing elements in multiple rows, thereby efficiently, in terms of silicon real estate, achieving complex functions not practical with analog and digital circuit techniques.

In the figure, the print data input 12 has N lines corresponding to 2 to the N levels of grey. Digital-to-analog converters (DACs) 40 and 41 convert the print data 12 and data (switching threshold) 47 from PROM 18 into analog current signals, respectively. These current signals are added via a transimpedance summing circuit 43. The output is connected to the multiplying or reference input of a third digital- to-analog converter 42 whose digital inputs (gain) 48 also originate from PROM 18. The PROM data modifies the analog print data to compensate for variations in driver circuitry and printing element characteristics. The output 44 of the multiplying digital-to-analog converter is connected to the input diffusion 46, thereby developing an analog charge signal within the driver module/chip 50.

The SYNC input 10 indicates start of page or start of line for initializing timing control circuit 14. The timing control circuit generates PROM address data 16 that corresponds to the same pixel position as the print data input 12. In addition, the timing circuit generates typical charge coupled device circuit timing waveform signals 20 for shifting a...