TONER LAYER FORMING DEVICE

PURPOSE:To prevent completely the occurrence of white stripes and the variance of the development density and to form always vivid and stable images by shaking a toner thickness control member while keeping this member parallel with a toner carrier and specifying the gap from the lowermost end of the shake range to the toner carrier. CONSTITUTION:While development is stopped, a control blade 5 is brought into contact with the surface of a nonmagnetic sleeve 2 by the elastic force of a coil spring 5. When an AC power source 17 is excited in a magnetic piece 15, and the control blade 5 is raised to a prescribed position against the elastic force of coil spring 20, and simultaneously, the control blade 5 is shaked vertically while being kept parallel with the axial line of the nonmagnetic sleeve 2. An extent H of shake is so set that the lower end position of shake is equal to the position of a space S between the blade 5 and the sleeve 2 required for formation of a toner layer 6 having a prescribed thickness, and shake is so controlled that its amplitude H is shorter than said space S upward this lower end position. Thus, a toner is loosened quickly even in case of flocculation to obtain images without white stripes neither the variance of density.