| 摘要 |
PURPOSE:To detect the toner density in a developer by a magnetic brush part speedily and accurately, and to control picture density and gradation, by feeding electricity in the orientation direction of a developer and detecting a flowing current. CONSTITUTION:When a distance between a magnetic drum and a blade or two magnetic drums at (c) is 5mm., the relation between the toner density and current is almost linear relation with E=100V and <=4.0wt% toner density in figure (b), and this has almost no variation even after 20,000 sheets are printed. Toner supplement is interrupted so that the current is 0.7muA, and the density varies between 2.7 and 2.9wt%, so it is controllable with 0.2wt% precision. Further, the toner density and current value has little variation similarly in figure (c) and variation width showing the precision is 0.3wt% has no large difference; and the time for setting specific density is reduced to a half as long as that of the example in the figure (b) and good responsibility is obtained. |
