LIGHT SENSITIVE DETECTION SYSTEM

摘要

A photoelectric detection system for a printer is described. The system is particularly useful for accurately detecting the position of type-bearing or printing elements of known width and spacing as they pass a predetermined location. An output signal is generated that substantially corresponds to the light and dark periods created as the elements pass between a light source and a detector. This output signal is integrated and compared with a reference signal that represents the ratio of the width of the elements to the spacing therebetween and the error is used to modify the light source and thereby adjust the output signal to correspond accurately with the dimensional criteria of the elements.