TONER CONCENTRATION DETECTOR OF DEVELOPER

摘要

PURPOSE:To prevent the developer from stagnating in a detecting case to which an inductance change detecting coil is mounted and accurately detect the change in toner concentration by letting the opening widths that said detecting case forms with a magnet roll for discharging satisfy the specific conditions. CONSTITUTION:The developer 1 in a detecting case 7 is led to outside the detecting case 7 by a rotating magnet roll 8 for discharging and the rate of its outflow is limited by the pass width (c) of the portion (gamma) by the outflow rate limiting plate 9 mounted roughly at the center in the bottom end opening of the detecting case 7 and the opening width (a) of the portion (beta) at the bottom end of the detecting case 7. On the other hand, in the bottom end portion (alpha) of the detecting case 7, the developer 1 equal to the opening width (b) attracted on the roll 8 advances into the detecting case 7. The opening width (b) is made smaller than (a) and more than zero and the difference (a-b) of the two opening widths is set at the optimum rate of discharge of the developer at which a coil 6 actuates properly. The limiting pass width (c) by the limiting plate 9 is so constituted as to assume a value of a-(a/2- b/2) or b+(a/2-b/2).