| 摘要 |
<p>PURPOSE:To prevent the drop-out of image lines, thinning fine image lines and splashing by using a developer contg. metal oxide powder and specifying the duty ratio of the AC bias to be impressed to a developing means. CONSTITUTION:The AC bias to be impressed to the developing means is specified to <50 duty ratio. A magnetic toner, fluidizing agent and the metal oxide powder having 0.6 to 5mum weight average grain size (mD4), 0.5 to 4mum number average grain size (mD1) and 1.0 to 2.4 (mD4)/(mD1) are incorporated into the developer. The AC bias to be impressed to the developing means is required to be <50% duty ratio, more preferably from 45% duty ratio to 10% duty ratio in such a case. The thinning of the image lines arises and the fine line reproducibility are degraded, in addition, the image density decreases if the duty ratio is below 10%. Such duty ratios are undesirable. Further, the developing means is preferably coated with the developer on a developer carrying member by using an elastic blade.</p> |
