| 摘要 |
PROBLEM TO BE SOLVED: To provide a reader, where the operability for excellent reading is enhanced by preventing erroneous recognition due to the effect of an external light. SOLUTION: A level of a dark output A is detected (15) from an output of a photoelectric conversion means 13, when no light is emitted from a light source 10, and when the level of the detected dark output reaches a preset level or higher, a notice means 16 informs the user of the reader of a fault in the dark output A so that the user of the reader recognizes it, when the dark output reaches a prescribed level or higher.
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