HP Color LaserJet Enterprise CM4540 Service Manual - Page 56

Sequence of operation The DC controller PCA controls the operating sequence, as described in the following table. Table 1-1 Sequence of operation Period Duration Description Waiting From the time the power is turned on, ● Heats the fuser sleeve in the fuser the door is closed, or when the product exits Sleep mode until the product is ● Pressurizes the pressure roller in the ready for printing fuser ● Detects the print cartridges ● Moves the ITB and developing unit to the home position ● Cleans the ITB and secondary transfer roller Standby From the end of the waiting sequence or ● the last rotation until the formatter receives a print command or until the ● product is turned off The product is in the Ready state. The product enters Sleep mode if the sleep command is received from the formatter. ● The product calibrates if it is time for an automatic calibration. Initial rotation From the time the formatter receives a ● print command until the paper enters the paper path ● Activates the high-voltage power supply Prepares each laser/scanner unit ● Warms the fuser to the correct temperature Printing From the time the first sheet of paper ● Forms the image on the enters the paper path until the last sheet photosensitive drums has passed through the fuser ● Transfers the toner to the paper ● Fuses the toner image onto the paper Last rotation From the time the last sheet of paper exits the fuser until the motors stop rotating ● Moves the last printed sheet into the output bin ● Stops the high-voltage power supply ● Stops each laser/scanner unit ● If another print command is received, the product enters the initial rotation period when the last rotation is complete. 4 Chapter 1 Theory of operation ENWW