Ricoh FW780 Service Manual - Page 334

EXPOSURE [A] 4 seconds after the sensor is activated, the original feed motor starts rotating. [B] This delay gives the user time to align edge [A] against the original entrance rollers [D]. This helps prevent skew. The original is fed through the machine to the scanning start position [E]. This machine scans the original backwards, starting with edge [B] and scanning towards edge [A]. The original is now ready to scan. Scanning The original is scanned, moving back towards the operator. When edge [A] activates the original registration sensor [F], the roll paper feed motor turns on. Copy paper begins to feed, and the registration clutch is activated. When edge [B] reaches the original feed start position [E] (26 mm ahead of the original registration sensor [F]), the original feed motor stops to wait for the copy paper. In the copy section, the registration clutch turns off once the copy paper's leading edge is 10 mm past the registration sensor [H]. The voltage is now applied to the charge corona. The original feed motor begins rotating towards the operator again at 60 mm/s, and the original is delivered to the exposure glass. Light from the exposure lamp [M] is reflected off the paper to the fiber optics array [L]. Once the original's edge [B] passes the original entrance sensor, the registration clutch and roll paper feed motor turn on again. The paper feed resumes and the copy paper is transported to the drum [I]. To measure the original length for cutting, the copier's CPU measures the time from when the original registration sensor detects edge [A] until the original entrance sensor detects edge [B]. The copy paper length is measured by counting the number of steps as the roll paper feed motor (a stepper motor) turns. Just before the paper is cut, the feed motor speed doubles. This creates a buckle at the trailing edge of the copy paper. The feed motor then stops as the cutter unit cuts the paper. Copying, however, continues. The buckle provides the necessary slack while cutting. When making duplicate copies, the original feed motor pauses, then changes directions again, and the original is fed back to the scanning position 200 mm/s. Once previous paper exits out of the roll feeder, the roll paper feed starts as well, and the process repeats. After all copies are made, the original is delivered to the original table. If original hold mode is enabled (SP16), the original will stop with edge [A] caught by the original entrance rollers. The original can be fed out by pressing the ! key. If original hold mode is not enabled, the original feeds out completely, and is not caught. B047/B048 2-2 SM