PURPOSE: To obtain an optical concentration sensor in which the cleaning performance of a condenser lens is enhanced on the measuring plane side.
CONSTITUTION: The optical concentration sensor comprises a light emission element E, a light receiving element D, and a holder H wherein an object is irradiated with light emitted from the element E and the reflected light is received by the element D in order to detect the concentration of the object. A lens L2 for condensing the emitted light is arranged in front of the emission element E whereas a lens L2 for condensing the reflected light is arranged in front of the receiving element D wherein each lens L1, L2 has one flat plane. Since the surface of the lens L1, L2 can be wiped by means of a cloth, for example, when it is contaminated with toner or dust, a highly accurate measurement of concentration can be conducted stably at all times.
KOBAYASHI TATSUYA
TSURUYA TAKAAKI
ISHIBE YOSHIHIRO
