DEVELOPER AND DEVELOPING METHOD

摘要

PURPOSE:To form an image having high quality by incorporating a toner mixed with specific pulverized silicic acid powder into a toner which is specified in the average grain size by a weight distribution and the grain size of the particles of the largest number in a number distribution and is limited in the number of particles of the grain size exceeding the same. CONSTITUTION:The toner mixed with the pulverized silicic acid powder contg. <=10% particles having 0.5-3.0mum weight average grain size and 8.0mum grain size in the weight distribution is mixed with the toner consisting of the particle groups having 3-10mum average grain size by the weight distribution, 1-8mum particles of the largest number in the number distribution and <=2% number of particles of the grain size exceeding 16mum. The toner which exhibits a deviation-free and sharp electric charge distribution is obtd. by combining the same with the pulverized silicic acid powder from which the secondary coarse powder particles of >=8mum grain size are removed by the specified ratio or above. The high-quality image which has high sharpness and gradation characteristic and is free from fogging and rippled images is thus obtd. under various conditions.