| 摘要 |
PURPOSE:To obtain a uniform and good frictional electric charge characteristic even in high- temp. and high-humidity or low-temp. and low-humidity environment by incorporating toner particles and fine spherical particles having the average particle size small than the average particle size of the toner particles and having >=10<11>OMEGAcm specific volume resistance into the titled developer. CONSTITUTION:This developer contains the toner particles and the fine spherical particles having the average particle size smaller than the average particle size of the toner particles and having >=10<11>OMEGA.cm, more preferably 10<12>-10<16>OMEGA.cm specific volume resistance. The fine spherical particles are obtd. by using a material having 10-<8>-10<5>OMEGA.cm specific volume resistance for an insulating resin and subjecting the material to a surface treatment. Since the fine spherical particles having the average particle size smaller than the average particle size of the toner particles are added and mixed to and with the toner, said particles contact the recesses of the toner particles and impart substantial electric charge to the recesses as well so that the respective toner particles are uniformly and satisfactorily charged. On the other hand,the surface of the fine spherical particles is treated with the low-resistance material having 10-<8>-10<5>OMEGA.cm specific volume resistance; therefore, the fine spherical particles play the role of a leak material and the always well balanced charge quantity is maintained without abnormally increasing the charge quantity even at and under the low temp. and low humidity. |
