Method of margin alignment and plane-to-plane registration in a tandem color electrophotographic machine
View Patent ↗A method of correcting registration in an electrophotographic machine includes the steps of adjusting one of a right margin and a left margin by setting a time delay, determining a longest line length of a calibration pattern, and adjusting an other of the right margin and the left margin to match the longest line length.
1. A method of determining a length of a scan path of a laser beam in an electrophotographic machine, said method comprising the steps of:
placing a calibration fixture into a predetermined place in the machine, said predetermined place being designated for a photoconductive element;
providing said calibration fixture with a first sensor and a second sensor;
detecting a start of the scan path with said first sensor;
detecting an end of the scan path with said second sensor; and
calculating a length of the scan path dependent upon said detecting steps, wherein said calculating step includes determining a number of pel slices occurring between a first time of a horizontal synchronization signal and a second time at which an end-of-scan pel is positioned at a predetermined location on said second sensor.
2. A method of determining a length of a scan path of a laser beam in an electrophotogranhic machine, said method comprising the steps of:
placing a calibration fixture into a predetermined place in the machine, said predetermined place being designated for a photoconductive element;
providing said calibration fixture with a first sensor and a second sensor;
detecting a start of the scan path with said first sensor;
detecting an end of the scan path with said second sensor;
calculating a length of the scan path dependent upon said detecting steps; and
determining a number of pel slices occurring between a first time of a horizontal synchronization signal and a second time at which a pel is positioned at a predetermined location on said first sensor.
3. A method of correcting registration in an electrophotographic machine having a rotating mirror for scanning a laser beam along a length of a scan path, said method comprising the steps of:
placing a calibration fixture into a predetermined place in said machine, said predetermined place being designated for a photoconductive element;
providing said calibration fixture with a first sensor spaced apart from a second sensor;
detecting a start of said scan path with said first sensor;
determine a right margin offset based on a location of said start;
detecting an end of said scan path with said second sensor;
determining a left margin based on a location of said end;
adjusting said left margin by changing a rotation speed of said rotating mirror to thereby adjust said length of said scan path; and
checking said length of said scan path.
4. The method of claim 3 , wherein said checking step comprises calculating said length of said scan path dependent upon said detecting steps.
5. The method of claim 4 , wherein said calculating step includes determining a number of pel slices occurring between a first time of a horizontal synchronization signal and a second time at which an end-of-scan pel is positioned at a predetermined location on said second sensor.
6. The method of claim 3 , comprising the further step of calculating a center of said scan path relative to said calibration fixture.
7. The method of claim 3 , comprising the further step of determining a number of pel slices occurring between a first time of a horizontal synchronization signal and a second time at which a pel is positioned at a predetermined location on said first sensor.