HP Color LaserJet Professional CP5220 Service Manual - Page 58

4. The cassette (CST) feed roller rotates. 5. The cassette (CST) pickup solenoid is driven at a specified timing. 6. The cassette (CST) pickup roller rotates and picks up the paper. 7. The cassette (CST) separation roller removes any multiple-fed sheets. 8. One sheet of paper is fed into the product. NOTE: The lift-up operation pushes up the lifting plate to keep the stack surface of paper at the pickup position. Figure 1-34 Cassette pickup operation DC controller M5 Pickup motor CST pickup solenoid SL1 CST pickup roller CST feed roller CST separation roller Lifting plate spring Lifter Cassette multiple-feed prevention The product uses a separation roller method to prevent multiple sheets of print media from entering the paper path. The cassette separation roller does not have its own driving force. Therefore the cassette separation roller follows the rotation of the cassette pickup roller. During normal feed, when the product picks up one piece of paper, the cassette separation roller is driven by the cassette pickup roller through one sheet of paper. Thus the separation roller rotates in the paper feed direction. During multiple-feed, when the product picks up more than one piece of paper, the low friction force between the sheets weakens the driving force from the cassette pickup roller. In addition, some braking 46 Chapter 1 Theory of operation ENWW