HP LaserJet 9040/9050 Service Manual - Page 87

Sequence of operation The engine control system controls operational sequences. Table 14 describes the sequences. Figure 22. Sequence-of-operation block diagram Table 14. Normal sequence of operation State Period Operation WAIT From the time the power is z switched on until the surface z temperature of the fuser and pressure rollers reach their z WAIT target value (four minutes or less) z z z z z z z z z Power on: CPU and ASIC initialize Fan rotation (fans 1 through 6 for 30 seconds, duplexer fan for 3 seconds) Formatter interface communication starts Fuser heaters turn on Cartridge check Cartridge-memory check for toner level Optional interface communication (duplexer, tray 1, tray 4, paper handling) Cassette checks (lifting and loading status) Jam check (auto flush/eject) Fuser-wrapping-jam detect Door open/sleep check Fuser-roller temperature control and delivery motor STBY From the end of the WAIT z (standby) period to the input of a print reservation command from the z formatter z -or- From the end of the LSTR period until either a print z reservation command is input from the formatter or until power is switched off Fuser control (fuser roller temperature-180°C [356°F]/ pressure roller 140°C [285°F]) Print reservation command (awaits INTR sequence) Fan-motor drive control (fans 1 through 5 half-speed rotation; fan 6 is off) If the standby state lasts five minutes or more, the fuser/ delivery motor is rotated for about 0.08 second to prevent the pressure roller from becoming deformed. Basic operation 71