| 摘要 |
PURPOSE:To form a good image having excellent durability in multiple pieces development under high humidity and extremely low humidity by specifying the grain size distribution of a one-constituent developer containing the inorganic fine power having the specific length-average diameter and a magnetic toner. CONSTITUTION:The inorganic power has the length-average diameter of 0.1-5mum, and a one-constituent developer contains 0.5-10wt.% of the inorganic fine powder to a magnetic toner as a reference, and it has the weight average grain size of 7-11mum. In the number-reference grain size distribution of the one-constituent developer, it contains 5-18 number % of grains having the grain size of 4mum or below, it contains 60 number % or above of grains having the grain size of 4-10mum. In the volume- reference grain size distribution, it contains 10vol.% or below of grains having the grain size of 12.7mum or above. The alternating bias electric field is formed between a developer carrier coated with the developer and a latent image supporter. The development side voltage constituent of this electric field is made equal to or larger than the reverse development side voltage constituent, and the applying time of the development side voltage constituent is made shorter than the applying time of the reverse development side voltage constituent. |
