2-10 Phaser 6180MFP Multifunction Printer Service ManualTheory of OperationThe Magnet Roll is covered by a thin semi-conductive sleeve over the surface.The Developer Bias voltage is supplied to this semiconductor sleeve from theHigh-Voltage Power Supply (HVPS). Developer Bias is negative DirectCurrent (DC) voltage combined with Alternating Current (AC) voltage. TheMagnet Roll is kept at constant negative voltage against the photoreceptorlayer of the drum by DC voltage. Therefore, at the area on the drum surfacewhere the negative electric charge does not decrease, potential is lower thanthe magnet roll, while the potential is higher than the magnet roll at the areawhere the negative charge on the drum surface decreases. The AC voltageshakes the Developer on the Magnet Roll surface, causing the toner totransfer to the drum.Thus, the negatively charged toner is attracted only by the area where thenegative charge has decreased on the drum surface from the Magnet Roll(electrostatic latent image) and the toner image is formed on the drum. Whenthe toner is attached, the negative charge at the portion of the drum increaseswhere the toner is located increases, the potential decreases, and the force toattract the toner decreases.Drum SurfaceTonerImageElectric Potentialon DrumDevelopingBias-V0 s6180mfp-183
