| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller capable of obtaining a clear image high in density up to the end of the service life of a toner cartridge and less in resistance irregularities and also capable of obtaining a stable imageis even when the use environment is changed, and to provide a process cartridge and an electrophotographic device which are capable of forming an image of high image quality and outputting the stable image for a long period of time. SOLUTION: In the developing roller 1 having a shaft core 2 and a resin layer 4 provided around the shaft core 2, the resin layer 4 contains fine particles of an inorganic ferroelectric substance including a metallic element in constituent elements, and when the start and completion temperatures of the endothermic peak measured by a differential scanning calorimeter, of the fine particles of the inorganic ferroelectric substance are defined as T<SB>ci</SB>and T<SB>cf</SB>, respectively, the difference between the T<SB>cf</SB>and the T<SB>ci</SB>is≥20°C to≤100°C. COPYRIGHT: (C)2008,JPO&INPIT |
