DRUCKER ODER AEHNLICHES AUSGABEGERAET

摘要

To detect a document in a printer, photodetectors. e.g. phototransistors Q1, Q2, ... ON are connected in a chain C with resistor R so that a change in the amount of light received by any detector due to a document at any position across the paper transfer passage causes a change in the current flowing through the entire chain C, the change being detectable by comparator COMP. The photodetectors may be arranged with opposed emitters (fig. 1), and 2 chains of interleaved detectors (fig. 3) allow skew document detection. <IMAGE>