Improved Sensing of Opening
Original Publication Date: 1979-Jan-01
Included in the Prior Art Database: 2005-Feb-19
In paper feeds and other operations, it is often necessary to sense one or more openings or "holes" by optical sensors which sense the absence of light. It appears that when the hole is lined up directly with the optical sensor, the blackness of the hole is often diminished because of reflections from the sides of the hole. In the present structure, the blackness of the hole is increased merely by tilting the walls of the hole at an angle with respect to the top opening which is a line with the sensor. In this manner, reflections through the hole are minimized as the blackness of the hole intensified.