HP Color LaserJet CM4730 Service Manual - Page 206

Pickup/feed system The pickup/feed system consists of various feed rollers that pick up and feed media. This MFP has four pickup sources: the MP tray, tray 2, and the two trays of the 2 X 500-sheet paper feeder. The primary delivery source is the face-down tray. The IPTU and stapler/stacker or 3-bin mailbox can also be used for output. The multipurpose tray paper sensor (SR4) detects the media presence in the multipurpose tray, and the cassette paper sensor (SR9) detects the media presence in the cassette. The paper stack surface sensor (SR10) in the cassette monitors the pickup position of the media stack surface. When the SR10 detects that the pickup position lowers to a certain level, the DC controller lifts the lifting plate up to maintain the media stack surface at a specified height. Figure 4-34 Pickup/feed system (1 of 2) on page 187 illustrates this system. The media size in the cassette and presence of the cassette installed in the MFP are detected by the cassette paper size detection switch (CSIZE SW). The cassette paper size detection switch consists of three switches. The DC controller controls ten motors: pickup motor, ETB motor, four drum motors, fuser motor, fuser pressure release motor, reversing motor, and lifter motor. There are three solenoids: cassette pickup solenoid, MP tray pickup solenoid, and duplexing solenoid, for the pickup operation. There are five photo interrupters: top of page sensor, fuser paper sensor, paper loop sensor 1, paper loop sensor 2, and paper reversing sensor, on the paper transport path to detect media arrival and passage. If the media does not reach or pass these sensors within the specified period of time, the microcomputer (CPU) on the DC controller determines the paper jam and notifies the formatter. Figure 4-34 Pickup/feed system (1 of 2) on page 187 and Figure 4-35 Pickup/feed system (2 of 2) on page 189 illustrate this system. 186 Chapter 4 Theory of operation ENWW