BAR CODE READER, OFF-SCALE ITEM DETECTING DEVICE FOR BAR CODE READER, AND ITS METHOD

摘要

PROBLEM TO BE SOLVED: To detect off-scale items by providing a plurality of mirrors to direct an optical beam along a path circulating the periphery of a heavy plate, a detector to receive the optical beam, and an alarm and alarming an operator about the placement of an item in the path of the optical beam. ;SOLUTION: One of pattern mirrors generates a sensor beam 39, and it is deflected toward heavy plate mirrors 35 by a polarizer mirror. The heavy plate mirrors 35a to 35c are arranged at the corners of a heavy plate 28 and circle the periphery of the heavy plate 28 to reflect the sensor beam 39. The mirror 35c reflects the sensor beam 39 toward an off-scale sensor 29 in a bar code reader 10, and the sensor 29 generates an alarm signal when an item 41 has blocked the sensor beam 39. An off-scale alarm generates a visible and/or audible index responsive to the alarm signal to an operator.;COPYRIGHT: (C)2000,JPO