HP Color LaserJet Enterprise CM4540 Service Manual - Page 122

Document feeder/scanner assembly The document feeder/scanner assembly consists of a document feeder and flatbed scanner. The document feeder can feed 50 pages of letter or A4 size paper at speeds up to 57 images per minute in simplex and 24 images per minute in duplex. The document feeder features legal size detection and customer replaceable feed and separation rollers and pads. The flatbed scanner also includes legal detection and does not require a scanner lock for transport. The sensors and motors in both the document feeder and flatbed scanner are controlled and monitored by the SCB that is located on the rear of the flatbed scanner. The copy process board (CPB) is integrated on the formatter. Image data is sent to the formatter through the scanner cable connected to the interconnect board (ICB). Scanner subsystem Figure 1-54 Scanner subsystem The scan control board (SCB), located on the rear of the scanner, provides control of both the scanner and document feeder components. The scanner power supply-located on the rear of the printer above the DCC-provides a +24v current. The formatter supplies a 3.3v current to keep sensors energized while the +24v current is turned off during Sleep. The optical unit contains a Xenon lamp that is driven by a fan-cooled inverter power supply. The scan control board (SCB), located on the rear of the scanner, provides control of both the scanner and document feeder components. The scanner power supply-located on the rear of the printer above the DCC-provides a +24v current. The formatter supplies a 3.3v current to keep sensors energized while the +24v current is turned off during Sleep. The optical unit contains a Xenon lamp that is driven by a fan-cooled inverter power supply. 70 Chapter 1 Theory of operation ENWW