Patent ID: 8571460

Claim:
A method for insuring printing accuracy in simplex and duplex imaging, for use in connection with at least one of an electrostatographic and a xerographic machine, the method comprising: providing a media sheet including a first side, a second side, a lead edge and a trail edge; positioning the media sheet in a conveying apparatus adapted to move the media sheet, the conveying apparatus including sensors and a datum, the sensors including a first leading edge sensor and a second leading edge sensor downstream of the first leading edge sensor to record the time of arrival of the sheet lead edge, and a trailing edge sensor adapted to record the time of arrival of the sheet trail edge; moving the media sheet through the conveying apparatus; calculating an edge arrival time difference between the arrival time of the sheet trail edge using output from the trailing edge sensor and the arrival time of the sheet lead edge using output from the leading edge sensor; calculating a correction factor using the difference between the edge arrival time difference and a predetermined arrival time difference between the lead edge and trail edge at the sensors; providing a registration device sensor, and recording a recorded lead edge arrival time at the registration device sensor; calculating a corrected lead edge time of arrival of the sheet to the registration device sensor based upon the edge arrival time difference; calculating a corrected lead edge time of arrival of the sheet to the datum; establishing a nominal velocity of the media sheet; calculating a measured velocity by dividing a distance between the first and second leading edge sensors by a time required to travel between the sensors; calculating a velocity correction factor by dividing the nominal velocity by the measured velocity; calculating a corrected sheet velocity using a target time of arrival of the media sheet at the datum, the corrected lead edge time of arrival of the sheet to the datum, and the velocity correction factor; and adjusting the conveying apparatus using the corrected sheet velocity to align items printed on both sides of the media sheet.