JPS6450079A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a photosensitive body from damaged by a density sensor and to attain the stabilization in the lapse of time in the detecting action of the density sensor by installing the density sensor so that it can be freely displaced between a detecting position where it closely faces the photosensitive body and a refuging position where it separates from the photosensitive body. CONSTITUTION:The density sensor (P sensor) 19 is constituted so that it can be positioned on the detecting position where it closely faces the photosensitive body 1 and the refuging position where it separates from the photosensitive body 1 by turning around a rotational axis 24 for displacing. A cleaning unit 9 or the photosensi tive body 1 can be detached from a copying machine main body in the axial direction of the photosensitive body. At such a time, the surface of the photosensitive body 1 can not be damaged with the P sensor 19 since the P sensor 19 also positions the refuging position where it separates from the surface of the photosensitive body 1, which is shown in a figure. Since a P sensor cleaner 27 is slided from the surface of the P sensor 19 while the P sensor 19 is turned and displaced between the detecting position and the refuging position, the surface of the P sensor is automatically cleaned every displacement. Thus, the surface of the photosensitive body can not be damaged and also detecting action can be stabilized in terms of the lapse of time.