| 摘要 |
PURPOSE:To provide the quality equiv. to the quality of an initial image to the image after continuous copying of many sheets by increasing the particle size of white and pale color toner particles larger than the particle size of black and colored toner particles. CONSTITUTION:This toner is prepd. by mixing the toner particles (A) contg. black and chromatic coloring agents and the white, pale color or transparent toner particles (B). Such toner particles are measured with a 'Coulter(R)' counter and the volume average particle sizes thereof are so determined as to be larger by >=1mum with the toner particles (B) than with the toner particles (A). The toner particle sizes in a developing device increase successively and the toner deposition on the image increases in the case of continuous copying. The toner particles are, thereupon, so formed that the ratio of the toner particles (B) having the larger particle size increases as compared to the initial period in order to maintain the sharpness of color tones. Since the particle size of the toner particle (B) is made larger than the particle size of the toner particle (A), many sheets of copies having good quality are obtd. |
