International Business Machines Corporation

Wayne A Overby

Russell Alan Budd

Mikel J Stanich

Bruce David Gibson

Joan Stagaman Goddard

James A Valent

Sherwood Kantor

This is an electronic scheme for correcting mechanical misalignment and electrical delays from laser beam to laser beam in the scan direction of a multiple beam laser scanning system for use in an electrophotographic machine. The position at which a reference beam is turned on is sensed and adjusted to a desired position. Thereafter, the positions at which non-reference laser beams are turned on are sensed and adjusted to the desired position. In one enbodiment, the energization of laser beams is positioned at the trailing edge of the second element of a photodector. In a second embodiment, the point of full laser energy is matched, beam to beam, at the junction of the same two elements in a CCD array. Programmable delay lines are used to obtain sub-pel resolution.

Pel placement correction in the scan dimension of a multiple beam laser

This is an electronic scheme for correcting for mechanical misalignment and chromatic aberrations from laser beam to laser beam in the scan direction of a multiple beam laser scanning system for use in an electrophotographic machine. Each beam is first corrected for mechanical misalignment and thereafter for chromatic aberrations. A reference laser beam produces two pulses near the start of scan (SOS) and two pulses near the end of scan (EOS). A non-reference laser beam then produces SOS and EOS pulses from which the mechanical misalignment is calculated. A gated clock is energized by the reference pulse and a tapped delay line is used for nanosecond resolution. After accomplishing correction for mechanical misalignment, chromatic aberrations are corrected by measuring the amount of total pel displacement of the non-reference scan line relative to the reference scan line and inserting appropriate delays at selected intervals throughout the non-reference scan in order to maintain pel placement accuracy to a desired tolerance.

Chromatic and misalignment compensation in a multiple beam laser

Motor test circuit for supplying an error indication signal if the speed variations of a motor under test exceed predetermined limits. The circuit includes a frequency-to-voltage converter or other source of voltage proportional to the motor speed and a reference source derived from the converter's output signal so that the test results are independent from errors due to drift in the converter's parameters caused by time, temperature, or other effects.

Growing community of inventors

Longmont, CO, United States of America

Wayne A Overby