| 摘要 |
PURPOSE:To detect a toner end with a high reliability by deciding it to be the toner end, when a ratio of a reflected light quantity of a toner image by a basic pattern and a reflected light quantity of the surface of a photosensitive body has become below a prescribed ratio. CONSTITUTION:When a surface density of a photosensitive drum D, and a P sensor pattern density are denoted as VSC and VSP, respectively, in case of VSC average value -nXVSP average value -nXVSP average value <0 (in this case, (n) is a value of 3-5), a reference pattern density is pretty weak. Also, in case when a toner end check FLAG is set to '1', the VSP average value is compared with the previous VSP average value, and if the present VSP average value becomes smaller than the previous VSP average value, the density of a toner image of a reference pattern becomes thick by replenishing a toner once, therefore, this FLAG is reset. On the contrary, if the present VSP average value becomes larger than the previous VSP average value, the toner image does not become thick even if the toner is replenished, therefore, it is decided to be a toner end. |
