Phase-Locked Loop Emitter Processor and Method of Monitoring Emitter Pulse Rates for Band Printers
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
Hardware and software improvements are used to reduce registration errors arising from discrepancies in the detection of the precisely spaced emitter openings in a print band and the corresponding generation of electric emitter pulses by an optical sensor. Referring to the figure, the printer band 1 includes a row of precisely spaced and shaped apertures to ultimately trigger a "fire" pulse or a "home" pulse. The apertures are optically sensed as they move by a detector 2, which generates a series of electric signals. The hardware improvements include inputting these electric signals on line 3 to a phase-locked loop (PLL) pulse generator 4, which generates pulses that are logically processed by processor 5. The processor outputs home or fire signals on lines 6 and 7 to the actuator control 8.