POSITION DETECTOR, ROTATION BODY DETECTING CONTROL DEVICE, ROTATION BODY RUNNING DEVICE, AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a position detector capable of performing a stable positional measurementat highly precisely at a high speed by comparing quantities of light rays received by an imaging element, thereby simultaneously performing the positional detection of a scale pattern in a direction orthogonal to the moving direction of a scale.;SOLUTION: An imaging element reads the mark patterns of the scale, in which a series of mark patterns of predetermined reflectivity or transmittance is formed. Thereby, the position detector detects the moved position of the scale. The mark patterns of the scale are almost identical and disposed in series in the main moving direction of the scale. The mark pattern is disposed such that with the mark pattern projected by the imaging element, part of the mark pattern in an auxiliary moving direction perpendicular to the main moving direction is projected.;COPYRIGHT: (C)2008,JPO&INPIT