Basic operation HP LaserJet 4500 series and 4550 series printer functions are divided into three systems: the image formation system, paper pick-up feed system, and engine control system. These systems are thoroughly described in this chapter.
To external device (host computer, etc.) through the video controller PCB Face-down tray ENGINE CONTROL SYSTEM Connector PCB Operation panel DC controller PCB Multi-purpose tray Face-up tray Fixing unit Pick- up unit Cassette Duplexing unit (option) Cassette paper pick-up unit Cassette Paper feeder (option) PICK-UP/FEED SYSTEM Figure 5-1 Basic system operation C7085-90921 Chapter 5 Theory of operation 103 LASER/SCANNER SYSTEM Scanning mirror Laser BD diode circuit Scanner motor Photo- Primary IMAGE sensitive drum charging rollerFORMATION Cleaner unit SYSTEM Developing unit Intermediate ITB cleaning transfer belt roller Secondary transfer roller