HP Color LaserJet CM4730 Service Manual - Page 198

DC controller PCB ETB ALIENATION SOLENOID DRIVE signal ETB MOTOR DRIVE signal Bk cartridge M cartridge SL3 M7 Transfer roller engaging cam C cartridge Y cartridge Transfer roller Transfer roller holder < Transfer roller engaged > < Transfer roller disengaged > Figure 4-29 Transfer roller engagement/disengagement control NOTE: The Y, M, and C photosensitive drums opposite the transfer rollers stop rotating when the rollers are disengaged. Calibration and cleaning The MFP automatically calibrates and cleans itself at various times to maintain the best print quality. You can also force the MFP to calibrate by selecting Quick Calibration or Full Calibration from the Administration, Print Quality, Calibration/Cleaning menu. While the MFP is calibrating or cleaning, it pauses printing. For most calibrations and cleaning, the MFP does not interrupt a print job, but waits for the job to complete before calibrating or cleaning. Table 4-4 Calibration timing and duration on page 178 shows when the MFP calibrates, the duration of the calibration, and the type of calibration that occurs. Table 4-5 Cleaning timing and duration on page 179 shows when the MFP cleans and the duration of the cleaning. The sections that follow discuss calibration and cleaning in more detail. Table 4-4 Calibration timing and duration Calibration occurrence Duration Type of calibration When you turn the MFP on. 75 seconds for calibration, but because of other initialization activities, the MFP takes a total of 2 minutes to be ready for printing DMAX, DHALF 178 Chapter 4 Theory of operation ENWW