Ricoh FW780 Service Manual - Page 172

Rev. 5/95 8. COPY QUALITY ADJUSTMENT -- General Information -- Image density is affected by the following factors: (1) Light Intensity (2) Bias Voltage (3) Toner Density (4) Grid Voltage (5) Charge Corona Current The items listed above must be kept in balance to maintain correct image density. In the field, image density should be adjusted first by changing the light intensity. (Adjust the light sensor voltage.) If results are unsatisfactory, the bias voltage can be changed. Also, if requested by the customer, the overall image density can be changed by changing the toner density. Normally, this should be kept at the normal position (factory setting). The grid voltage and charge corona current are carefully adjusted at the factory. Any adjustment out of the adjustment standards will result in over toning, toner scattering, dirty background, or light image density problems. The grid voltage and charge corona current adjustment should be done only when replacing the Charge/Bias/Grid power pack, or to correct certain problems with image density after checking all other possible causes. NOTE: Adjusting grid voltage will not affect toner supply amount, but will affect the amount of charge reaching the drum. Exposing the the drum to light will not disipate all residual voltage resulting in overtoning and background. A163 5-38 SM