| 摘要 |
PURPOSE:To elevate the printing quality preventing variations in the concentration by a method wherein a charged toner is positioned below a space through which a measuring light passes and the passage of the measuring light is measured to determine the level and distribution of charge of the toner. CONSTITUTION:A toner suction electrode plate 5 is placed above a toner carrying member 2 leaving a clearance 4 at a distance (d). As the toner is charged negatively, a positive potential with respect to the member 2 is applied to the electrode plate 5 from a potential supply source 6. Then, the light from a light source 7 is divided with a splitter 8 and a measuring light 9 is detected with a measuring light receiver 13 passing through the clearance 4 while a reference light 10 is detected with a reference light receiver 14 passing through a space clear of any obstacle. The intensities of lights detected with the light receivers 13 and 14 are compared with a detection circuit 15 and the resulting difference is outputted to a measuring circuit 16. In this manner, an electric field attracting toner upward is formed in the clearance 4 measuring the passage of the measuring light 9 and the intensity of the electric field is increased sequentially to determine the correlation of the passage of the measuring light 9 with the intensity of the electric field and thus, the distribution of the amount of toner is obtained with respect tot the charge level thereof based on the correlation. |
