| 摘要 |
<p>PURPOSE:To prevent malfunction by measuring the time from the detection of the leading end of an article by an input side sensor to the detection by the output side sensor and using the time obtained by adding the time multiplied by a constant to said time as readable time. CONSTITUTION:When a commodity 1 is carried in the arrow A direction, manual operation is executed so that a bar code 2 on the back of the commodity 1 passes on a reading window 4 of a reader 3. The reader 3 arranges a sensor G1 on the input side of the window 4 and a sensor G2 on the output side so that a scanner can be effectively used only the period when the commodity 1 passes through the reading window 4. Since the sensor G2 is located on the center of the window 4 in order to prevent interruption by the left hand or the like of the operator, the time from the OFF of the sensor G2 to the real completion of the passing of the final end of the commodity 1 through the window 4 is found out by calculation. Therefore, a counter circuit and a multiplier are formed. The time T1 from the ON of the sensor G1 to the ON of the sensor G2 is measured, the time T2=aT1 obtained by multiplying the time T1 by a constant (a) is found out and the time T1+T2 is used as a reading area.</p> |
