HP Indigo 30000 CA493-00130 Rev - Page 21

4 Calibrations This chapter describes how to calibrate the charge roller. Charge roller voltage calibration (a.k.a. auto bias calibration) The charge roller's voltage properties deteriorate during normal usage, due to exposure to the high voltages. The charge roller Voltage Calibration is performed automatically together with the Auto Bias Calibration. ● Dirt on the balancing roller reduces its electrical efficiency, and causes the charge roller to be calibrated at a higher voltage. Clean the balancing and charge rollers every 150K impressions using the supplied water based wipes. ● Using Pause mode frequently with the press on (where the charge roller remains active), increases "wasted charge cycles", reducing the life-span of the charge roller. Charge roller seam area calibration (a.k.a. charge roller leveling) ● The PIP drum surface has an indented area where the PIP foil joins, called the "seam" (under the PIP holder). A pair of stepper motors lift the charge roller over the seam area to prevent damaging the roller. ● The Seam Calibration wizard is performed automatically at every "cold start". It uses the encoder unit to record the correct press angle of the seam. ● Incorrect press angle values may cause: - Charge roller bouncing while engaging: this affects the PIP charge, and causes dark banding at the leading edge of the print. - The charge roller picks up imaging oil from the PIP trailing edge, and transfers it to the image (also called "imaging oil pick-up"). Figure 4-1 The charge roller seam area 1 Balancing roller 2 Charge roller 3 PIP drum Calibrations 19