DISTANCE MEASURING DEVICE, DISTANCE MEASURING METHOD, IMAGE READING DEVICE, IMAGE READING METHOD AND IMAGE FORMING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a distance measuring device and a distance measuring method, which enables easy and accurate measurement of a distance to a document or an object irrespective of the state of a light irradiating surface of the document or object. SOLUTION: The distance measuring device 1 of the present invention comprise a light emitting diode 2 which radiates light on an object to be measured, and phototransistors 3 and 4 which receive reflection light from the object to be measured. The phototransistors 3 and 4 have a plurality of characteristics where there is correlation between the amount of light received and the distance to the object to be measured. The phototransistors 3 and 4 are configured to receive reflection light for each characteristic, and especially, is configured so that at least a part of the reflection light received for each characteristic receives reflection light radiated on the same portion of the object to be measured. COPYRIGHT: (C)2005,JPO&NCIPI