Image-Density-Decrease Phenomenon in ElectrophotographicMono-Component Developing Process

抄録

The image-density-decrease phenomenon, which occurs at the initial printing with a brand new developing cartridge and at a printing done after several days of rest, during which printing is not done, was studied in the mono-component developing process. The toner charge, q/m, and toner supply, m/a, were measured by a suction type Faraday cage. The mechanism of the image-density-decrease phenomenon is discussed based on q/m, m/a and fluidity of toner. The image-density-decrease phenomenon was found to occur with decrease in m/a, and not with increase in q/m. The cause of the decrease in m/a is the shortage of the toner supply to the supply roller. Finally, modifications of the developing unit and the toner additives to eliminate the image-density-decrease phenomenon are proposed.