Method and apparatus for grey level recording using multiple addressability
US5025322A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 1989 |
| Grant date | Jun 18, 1991 |
| Priority date | — |
| Expiry date | Dec 18, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F1/025
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A grey level non-impact recording apparatus and method provides data signals to a recording head having N recording elements per inch so that M sub-lines per inch can be recorded, wherein M is greater than N. In a specific example of a 400 dpi LED printhead, grey level data is sent to the printhead at a rate to record say 2400 lines per inch to provide a resolution of 400 dpi.times.2400 dpi grey level sub-pixels. Data from a data source may have a pixel resolution of 1/400".times.1/400" and the apparatus employs six sub-lines to record each of these pixels. The control for controlling the duration of recording of each LED for each sub-line includes a comparator which receives a grey level data signal at one input terminal and pulses representing a time changing count at another terminal. The count is produced by counter means and changes in response to signals from a clock means. Fine control over exposure, particularly at the "toe" of the exposure curve, is provided by a vernier-like clocking scheme wherein the counter means responds to alternate master clocks during recording of alternate sub-lines. The master clocks generate clock pulses at slightly different frequencies which t…
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