HP 2700n Service Manual - Page 90

Engine control system The engine control system coordinates all printer functions and drives the other three systems. The engine control system contains the DC controller, high-voltage power-supply PCB, and low-voltage power-supply unit. Figure 4-1 Engine control system components Table 4-1 Sequence of operation Period WAIT STBY (Standby period) INTR (Initial rotation) PRINT LSTR (Last rotation) Duration Purpose Remarks From the time the power is turned on or the door is closed until the drum-phase adjustment is complete Clears the potential from the drum surface, adjusts the drum phase, and cleans the ETB Detects the toner level, cartridge presence, and environment; completes any required calibration (color registration control and image stability) From end of the WAIT or LSTR period until either the print command is received from the formatter or the power is turned off Maintains the printer in readiness for a print command The printer enters sleep mode when the formatter sends a sleep command, and performs color registration and the image stability control when the formatter sends those commands From the time the print Prepares the photosensitive command is received until the drum for printing media is picked up From the end of INTR period until the fuser paper sensor detects the trailing edge of paper Forms the images on the photosensitive drum and transfers the toner image to the print media Performs image stabilization at a specified print interval or at specified times From the end of the PRINT period until the delivery motor stops rotating Moves the printed sheet out of the printer The printer enters the INTR period as soon as the formatter sends another print command 72 Chapter 4 Theory of operation ENWW