Systems for performing laser beam linearity correction and algorithms and methods for generating linearity correction tables from data stored in an optical scanner

A method of computing a linearity profile to compensate for scan line velocity nonlinearity in an electrophotographic device comprising:

• obtaining a plurality of laser beam position measurement comprising a plurality of test points that measure for each test point, a scan direction position and a corresponding time value;
• initializing an accumulated angle;
• computing an initial scan direction position based upon said starting accumulated angle;
• assigning a first insertion time;
• assigning a second insertion time;
• and
• performing for a plurality of Pel locations along a laser beam scan path:
• determining an ideal scan direction Pel location based upon a predetermined correction resolution;
• computing a first postulated angle based upon said first insertion time and said accumulated angle;
• converting said first postulated angle to a first postulated position based upon select ones of said plurality of measurements;
• computing a second postulated angle based upon said second insertion time and said accumulated angle;
• converting said second postulated angle to a second postulated position based upon select ones of said plurality of measurements;
• comparing said ideal scan direction Pel location to said first and second postulated positions;
• storing a correction value corresponding to a select one of said first and second postulated positions that is minimizes an error computation relative to said ideal scan direction Pel location;
• and
• updating said accumulated angle to said first postulated angle if said first postulated position results in less error than said second postulated position, and updating said accumulated angle to said second postulated angle if said second postulated position results in less error than said first postulated position.

A laser beam scan line velocity linearity registration system comprising:

• a slice clock operatively configured to output slice clock pulses having a fixed frequency;
• a pel clock generator programmably configured to generate pel clock pulses based upon said slice clock pulses and correction values input thereto;
• a pel clock counter communicably coupled to said pel clock generator, said pel clock counter operatively configured to determine a count value corresponding to a count of pel clock pulses;
• a linearity table having stored therein, a plurality of correction values, said linearity table communicably coupled to said pel clock counter and said pel clock generator such that an associated one of said correction values is selected from said linearity table based upon said count value from said pel clock counter and is communicated to said pel clock generator, wherein a duration of a corresponding pel clock pulse is determined from said correction value;
• and
• a video unit arranged to communicate Pels to a corresponding laser beam, said video unit coupled to said slice clock and said pel clock generator, wherein a duration of each Pel is determined by said slice clock, and spacing between Pels is determined by said pel clock generator.