US 5,966,231 A · Method and apparatus for aligning multiple laser beams

Abstract

Compensation for beam separation of multiple laser beams of a laser printer simultaneously scanning a photoconductor drum is automatically made. The time for the lead beam to travel a predetermined distance is ascertained and then the separation time between the lead beam and one of the remaining beams is determined. When using only one light sensor, the time for the lead beam to travel the predetermined distance is the scan time of the lead beam. When using two light sensors, the time for the lead beam to travel the predetermined distance is the time for the lead beam to travel between the two light sensors, which define the predetermined distance, in the same scan. This determination of the time for the lead beam to travel the predetermined distance and its separation time from another of the remaining beams is continuously made for all of the remaining beams even during printing. If the beam separation time of each of the remaining beams from the lead beam is large enough for the one light sensor to generate distinct pulses for the lead beam and any one of the remaining beams during the same scan, the separation time for any one of the laser beams can be directly measured in only one scan.

Claims28

Dependent claims

An apparatus for continuously measuring and compensating for beam separation in a multi-beam raster system including:

producing means for producing a plurality of laser beams;
selecting means for selecting one of the plurality of laser beams as a lead beam;
causing means for causing the plurality of laser beams to continuously scan a recording medium simultaneously in parallel scan lines in which the plurality of laser beams is separated from each other;
determining means for determining the separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam;
storage means for storing the determined separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam;
delay means for delaying data transmission for each of the remainder of the plurality of laser beams in accordance with the determined separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam;
and changing means for changing the determined separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam in said storage means when said determining means determines a different separation time from the stored separation time.

4 more elements

A method for continuously measuring and compensating for beam separation in a multi-beam raster system including:

producing a plurality of laser beams;
selecting one of the plurality of laser beams as a lead beam;
continuously scanning the plurality of laser beams simultaneously over a recording medium in parallel scan lines in which the plurality of laser beams is separated from each other;
determining the separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam;
storing the determined separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam;
delaying data transmission for each of the remainder of the plurality of laser beams in accordance with the determined separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam;
and changing the stored determined separation time in the scan direction of each of the remainder of the plurality of laser beams from the lead beam when a different separation time is determined from the stored separation time.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for aligning multiple laser beams

Life of this patent

Method and apparatus for aligning multiple laser beams

Life of this patent

Abstract

Claims28