READING UNIT AND MARKING CARD FOR OPTICAL MARK READER

The present invention relates to a reading unit and a marking card for optical mark reader.The reading unit comprises a plurality of optical sensing devices (R1, R2, R3, R4 . . . ) corresponding to a plurality of marks (M1, M2, M3, M4 . . . ); and a plurality of counters (CT1, CT2, CT3, CT4 . . . ) for converting output signals to output values corresponding to an amount of light sensed, and for sending the output values to a central processing unit (CPU).The CPU performs an answer checking process by a logical calculation based on the output values from the counters (CT1, CT2, CT3, CT4 . . . ).