GRANULAR BODY LEVEL DETECTOR AND DEVELOPING DEVICE

PURPOSE:To avoid impaired precision even after long use by installing a granular body the surface of a roller which is rotatably mounted on a preset position on a casing member housing a granular body, and detecting the existance of the granular body by the sensor. CONSTITUTION:When a toner 1 exists in a casing 3, a toner sensor 10b which is fitted on the surface of a roller 10a does not detect the toner 1 during passing through the upper part where the toner 1 does not exist and detects the toner 1 during passing through the lower part where the toner 1 exists, and a control means 10d counts a time (t) when the toner sensor 10b is present in the toner 1 to calculate the height of the toner 1. The control means 10d rotationally moves a cam 93 corresponding to the calculated height of the toner 1 to restrict a layer thickness restricting means 9. It is thus possible to prevent the granular body from impairing detecting function.