KX-MC6020RU, KX-FAP317A, KX-FAB318A - Panasonic Fax Service Manual (repair manual). Page 121

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This Laser Printer creates an image on paper using a technique called laser electrophotography. The printer uses the electro-
graphic process known as Discharged Area Development, or “write black”. In this process, a digitally modulated laser scans later-
ally across a rotating OPC (Organic Photo Conductive) drum that has been negatively charged. Wherever the OPC drum is
exposed by laser beam, the image is written and toner is transferred.

To generate a color image, the OPC drum suitably rotate to the image length, one for each primary color and black. During each
successive pass, the laser exposes the portions of OPC drum that correspond to the primary color’s component of the image. Toner
is attracted to the laser-exposed portions of the OPC drum.
As each color layer is developed on the each OPC drum, they are transferred to the accumulator belt until all four color layers even-
tually reside one on top of the other on the accumulator belt. At this point, a sheet of paper is advanced under the accumulator belt
and the toner is transferred to the sheet of paper. The paper advances to the fuser, where heat and pressure permanently bond the
toner to the paper. From the fuser, the paper is driven to the output tray.

A cleaning blade scrapes residual toner from the OPC drum before the next primary color toner is applied to the OPC drum. This
prevents contamination of the next color layer. The cleaning blade is in constant contact with the OPC drum.
An accumulator belt cleaner scrapes residual toner from the accumulator belt. This prevents “ghosting “of the next print. The blade
only comes in contact with the belt after the accumulated toner layers are transferred to the sheet of paper