| 摘要 |
PURPOSE:To prevent an irregularly reflected light from a luminous flux, from being made incident on a light receiving element, by providing a light emitting element, the light receiving element and conductive glass, etc. CONSTITUTION:A light beam is radiated from a light emitting element 21, and a reflected light by a concentration detecting roller 10 of its radiated light is received 22. This received light quantity corresponds to the quantity of a toner stuck onto the surface of conductive glass 25. Also, in a process that the light beam radiated from the element 21 transmits through the inside of the glass 25, for instance, when a part of a radiated luminous flux L1 is brought to an irregular reflection L3 by a conductive layer 25a, or brought to an irregular reflection L4 by stuck color toner 41 reflected light beams L1, L4 are brought to light shielding 26 at the time of passing through the glass 25. Also, since this light shielding plate 26 is constituted of a black frosting tape, the greater part thereof is attracted by the light shielding plate 26. Accordingly, it can be prevented that the irregularly reflected light beams L3, L4 are made incident on the light receiving element 22 on which a reflected luminous flux L2 by the roller 10 is made incident. |
