Hewlett-packard Company

Jeffrey A Sunamoto

William D Meyer

Craig T Johnson

Christopher Karl Schroeder

Stephen B Witte

Gary W Gragg

A lamp control scheme for rapid warmup of a cold cathode fluorescent lamp, to minimize the warmup time while maintaining long lamp service light. The lamp is over-driven with high current for up to a predetermined time limit to accelerate mercury vaporization. The drive current is then reduced to a normal level. The scanner light output is monitored by a sensor circuit, and the system waits until the light output exceeds a minimum output and the light profile is sufficiently stable. The scanner is then calibrated to a white reference, and the closed loop control of the signal level is activated. The scan or copy process is now performed, and the light level control is deactivated as needed. Thereafter, between uses the lower lamp current is 40% of normal level to keep the lamp warm while extending the life of the product. If the product has not been used in a long time, the lamp is turned off.

Lamp control scheme for rapid warmup of fluorescent lamp in office

A multiple printhead cartridge color thermal ink jet printer having apparatus for measuring the offsets between the multiple printhead cartridges each of which includes a nozzle array of one or more columns of nozzles, each column being parallel to the media axis of the printer. The cartridges are individually operated, stationarily and while scanning, to fire drops at an aperture plate interposed between an optical drop detector and the nozzle arrays of the printhead cartridges. The detection of drops passing through the aperture plate and the non-detection of drops blocked by the aperture plate provide information which is utilized in conjunction with the nature of the operation of the cartridges that produced the detected drops to determine the positions of the nozzle arrays of the cartridges relative to each other. The optical drop detector includes optical light benders that advantageously positions the optical detection zones of the optical detector closer to the aperture plate, which allows higher drop fire rates to be utilized for offset determination.

Growing community of inventors

San Diego, CA, United States of America

Jeffrey A Sunamoto