Linear array sensor for copy sheet registration

An apparatus for detecting a leading edge or a trailing edge of a moving sheet, including:

• an elongated light source extending in a direction substantially parallel to the direction of the moving sheet;
• a plurality of sensors arranged in an array extending in a direction substantially parallel to said elongated light source in a light receiving relationship therewith, said elongated light source and said plurality of sensors defining a passageway through which the moving sheet passes;
• and
• a support having said elongated light source mounted movably thereon so as to position said light source relative to said plurality of light sensors.

A printing machine of the type in which a leading edge or a trailing edge of a moving sheet are detected, wherein the improvement includes:

• an elongated light source extending in a direction substantially parallel to the direction of the moving sheet;
• a plurality of sensors arranged in an array extending in a direction substantially parallel to said elongated light source in a receiving relationship therewith, said elongated light source and said plurality of sensors defining a passageway through which the moving sheet passes;
• a controller, said plurality of sensors transmitting a signal to said controller, said controller, responsive to the signal from said plurality of sensors, indicating the leading edge or trailing edge of the moving sheet;
• and
• means associated with said plurality of sensors, for generating a calibration reference signal and transmitting the reference signal to said controller to calibrate said controller.

A printing machine of type in which a leading edge ortrailing edge of a moving sheet are detected, wherein the improvement includes:

• an elongated light source extending in a direction substantially parallel to the direction of the moving sheet;
• a plurality of sensors arranged in an array extending in a direction substantially parallel to said elongated light source in light receiving relationship therewith, said elongated light source and said plurality of sensors defining a passageway through which the moving sheet passes;
• and
• a support having said elongated light source mounted movably thereon so as to position said light source relative to said plurality of light sensors.