摘要 |
Signals indicating ink-discharge presence control priming and preferably halt document creation pending ink resupply-or pending an operator command to go on without resupply. A detector senses ink discharge; circuits including a programmed microprocessor apply the detector signal to control, most typically, pen priming or repriming-and preferably related functions including suspension of printer operation. The detector preferably includes an optical source and detector along an optical path that intersects an ink-discharge path. With a pen that has multiple ink-discharge nozzles, preferably the apparatus distinguishes between ink discharge from the different nozzles (by correlation with nozzle-actuating pulses), and accordingly controls priming of each nozzle independently. Preferably this system is operated before starting to print a new sheet and upon newly installing a pen. In event of inadequate ink discharge, progressively more-energetic priming impulses (higher voltage or duration, or both) are directed to the pen, until adequate discharge results or no further energy increase is deemed suitable.
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