Methods and Apparatus for Ascertaining Sensor Signal Delay in an Electrophotographic Device

A method of measuring sensor delay in a device, comprising:

• providing a sensor having a center, a leading edge and a trailing edge defined along a direction of laser scan travel;
• repeatedly passing a laser beam along the sensor in the direction of laser scan travel;
• and
• during the repeatedly passing the laser beam, determining when the sensor actually sends a signal upon being sufficiently impinged by the laser beam, thereby indicating an apparent leading edge of the sensor between the leading edge and the center along the direction of laser scan travel.

A scanning device, the device comprising:

• a laser for generating a laser beam;
• at least one position sensor to provide a reference position of the scan lines formed in the alternating directions, the at least one position sensor asserting a signal responsive to the laser beam impinging thereupon;
• and
• a controller for repeatedly passing the laser beam along the sensor in a direction of laser scan travel, wherein during the repeated laser beam passes, the controller samples a plurality of times from a reference point to determine when the at least one position sensor actually sends a signal upon being sufficiently impinged by the laser beam, thereby indicating an apparent leading edge of the sensor between the leading edge and the center along the direction of laser scan travel, and further during the repeatedly passing the laser beam, turns the laser beam on from off at different locations in the direction of laser scan travel to determine if the at least one position sensor asserts the signal thereby indicating an apparent trailing edge of the at least one position sensor between the center and the trailing edge along the direction of laser scan travel.