Photoreceptor Erase

Figure 7 A schematic of a process in which the various steps are arranged around the circumference of a photoreceptor drum. Here, (1) is the corona charging apparatus, (2) the exposure system, (3) the development system, (4) the transfer corona, (5) the fusing apparatus, (6) the cleaning system, and (7) the erase exposure system. Processes of this kind are widely used for printer and low-volume copier applications.

For webs, the substrate electrode is usually a vapor-deposited, semitransparent metal layer (Ritchie and Fenn, 1987 Chen, 1993). Al, Ni, and Cr are commonly used. The use of semi-transparent electrodes permits the use of rear exposures for erase purposes. In the case of drums, the metal cylinder serves as the electrode. Usually, a thin, less than 1 pm, blocking layer is interposed between the electrode and the photoreceptor to prevent charge injection. This layer must not be so thick that a residual potential builds up during cycling. Many insulating polymers have been used acrylic polymers, epoxy resins, polyamides, polyesters, polyphosphazenes, polysiloxanes, polyurethanes, vinyl polymers, etc. 

Figure 17 Sensitometry as a function of cycle number. The first cycle characteristics, Vdark, Vmidy and Verase correspond to the voltages obtained with no exposure (dark), exposure to one-half of the initial potential (mid), and those obtained following the erase exposure. The potentials obtained with the same exposures after 104 cycles are also shown. In this example, the photoreceptor fatigued with decreasing Vdark and increasing Verase These characteristics are often described as cycle-down and cycle-up.

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