HP Color LaserJet CM4730 Service Manual - Page 212

determine the actual size of the sheet. If this measured size differs from the size specified by the formatter or the switch combination, the DC controller determines a mismatch. The sheet is ejected from the MFP, and the MFP stops. Cassette pickup operation This MFP uses the pickup arm method for high-speed media pickup. The pickup arm presses the pickup roller down on the media stack to feed the media one by one. The pickup roller is attached to the pickup arm and it is normally held at the original position by the pickup arm. When the pickup solenoid (SL2) is turned on, the pickup cam rotates and lowers the pickup roller onto the media. The following is the operational sequence of the cassette pickup mechanism. 1. When the DC controller turns the cassette pickup solenoid (SL2) on during the cassette pickup operation, the driving force of the pickup motor (M9) causes the cassette pickup roller and the pickup cam to rotate. 2. As the pickup cam rotates, the pickup arm goes down and the rotating cassette pickup roller touches the media surface. The media in the cassette is fed into the MFP one sheet at a time. 3. The pickup cam rotation allows the pickup arm to go up and the cassette pickup roller disengages from the media surface. 4. The cassette pickup roller stops rotating. DC controller PCB PICK-UP MOTOR CONTROL signal Pick-up motor Cassette pick-up solenoid M9 SL2 Pick-up arm Cassette pick-up roller Lifting plate Pick-up cam Figure 4-37 Cassette pickup Media lifting operation This operation maintains the position of the media stack surface at a specified height for a stable pickup operation. The DC controller rotates the lifter motor (M10) and raises the lifting plate on which the media stack is loaded. The DC controller monitors the cassette paper sensor (SR9) and the media stack surface sensor (SR10) when the MFP is turned on, the cassette is installed, and during the printing operation. 192 Chapter 4 Theory of operation ENWW