| 摘要 |
PROBLEM TO BE SOLVED: To improve the accuracy of an optical sensor in the measurement of a quantity of a toner attached to the surface of an image carrier and to prevent erroneous judgment of a quantity of the toner in a toner storage device, by judging the complete consumption of a quantity of the toner in the toner storage device by the use of detection data obtained after input-and-output correction is made for the optical sensor. SOLUTION: The surface of an optical sensor 6 becomes different from the original state by being soiled with dust, as it is used. Also, the input-and- output correction of the optical sensor 6 is needed for correcting a variation in the surface of a photoreceptor 11, structural variations such as an angle at which the sensor 6 and the photoreceptor 11 are oppositely set and a distance between them, and variations in electrical/optical input-and-output characteristics. Therefore in a station in which a toner is not attached to the surface of the photoreceptor 11, an empty state in a toner storage device 14b is judged using detection data obtained right after the input-and-output correction of the optical sensor 6. This can prevent erroneous judgment such as overlooking an empty state in the toner storage device 14b. |
