| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device with a toner concn. measuring function where correction is made possible so as to perform accurate measurement though a sensor characteristic for measuring toner concn. is varied and the density of a toner image is varied. SOLUTION: An electrostatic latent image formed by exposing an electrified photoreceptor 1 is developed by the developing units 4a, 4b, 4c and 4d of four colors of yellow, magenta, cyan and black, and the toner image is formed at the photoreceptor 1, and it is transferred on a transfer drum 5. A toner concn. measured value obtained by a light emitting part 16a and a light receiving part 16b is corrected to an exact value before forming the toner image. Two kinds of emitted light quantities are decided based on reflected light from a part painted in white formed on the transfer drum 5. The output value of the light receiving part 16b for the toner concn. is made closed to a reference value by comparing received light quantity with the reference value. |
