Patent ID: 6014161
Filing Date: 2000-01-11
Classification: H04N

Abstract:
A system for calibrating pulsewidth modulation in a laser printer, components of the laser printer producing timing variations in a pulsewidth modulated signal, the timing variations producing variations in pulsewidth between a desired output pulsewidth and an actual output pulsewidth, the system comprising:(a) means for selecting the desired output pulsewidth;(b) means responsive to the desired output pulsewidth for producing the pulsewidth modulated signal;(c) a laser for providing output pulses responsive to the pulsewidth modulated signal, the output pulses having the actual output pulsewidth;(d) sensing means for sensing the actual output pulsewidth of said output pulses and providing a signal indicative of the actual output pulsewidth;(e) calibration means for modifying the pulsewidth modulated signal responsive to the signal from said sensing means, said calibration means compensating for the variations in pulsewidth; and,(f) feedback means interconnecting said sensing means and said calibration means, said feedback means providing the signal from said sensing means to said calibration means.