| 摘要 |
PURPOSE:To accutately detect the specific concentration of the toner of developer in spite of a simple, inexpensive structure, to prevent the flow of a developing bias voltage into the ground, scattering of the developer, etc., and to maintain satisfactory image quality all the time, in the device which irradiates an automatic taner probe with light and detects the specific concentration of the toner of the two-component developer kept in a developer storage part from its reflectance. CONSTITUTION:By making the outside diameter of the automatic toner probe 61 almost equal to that of a photosensitive drum 20, a developer magnetic brush satisfactorily comes into contact therewith. Also, by covering an insulation part between the photosensitive drum 20 and the automatic toner probe 61 with insulating tape 73 as an insulating covering member, the developer magnetic brush is prevented from coming into contact therewith. Thus, the flow of a developing bias voltage impressed to a developing sleeve, into the ground is prevented and the sticking of the developer is also prevented. |
