Chapter 22-19F-2-18When an original is placed on the original tray, the light-blocking plate operates in keeping with the detecting lever of the LGL sensor to block the light of thephoto interrupter. The machine identifies whether or not the original is LGL with reference to the LGL sensor signal (LG_S) and the width of the original. Themachine communicates the original size information to the host machine as soon as the Start key is pressed.F-2-19b. Detecting the Size of the Original in Width Direction.The width of an original is detected using the original width detecting volume (VR1) found inside the original tray. The volume operates in conjunction with theslide guide, its resistance changing (analog) as the slide is moved. The ADF driver PCB reads these changes in resistance as the original size signal (WIDTH), andrecognizes them as specific widths.To make sure that the original width volume (VR1) correctly detects A4R/LTRR and A5R/STMT widths, a special AB/inch sensor (PI4) is used inside the originaltray; the sensor goes '1' (AB/inch identification signal) when the width of the original is 197 mm or more and less than 214 mm.ADF driver PCBTrailing edge of the original(small size)BNG_SBNG_S_LEDTrailing edge of the original(large size)Read standing by positionPI7PI8ADF driver PCBLG_S Detecting leverLarge size originalPI4
