PURPOSE: To enable a uniform developer layer to be formed for a long time by using a flexible material high in electric resistance as the leaf spring material of a layer regulating member and regulating the contact pressure of said member to a developer carrying body to ≤30g/cm.
CONSTITUTION: The leaf spring material 7 for forming the layer thickness regulating member 5 is selected from a thermoplastic resin, such as polyethylene, polypropylene, polyacetal, or nylon, having an electric resistance of ≥1012Ω and an elastic modulus of 2×104W3×106kg/cm2, and a soft elastic material 8 to be used in combination with said leaf spring material 7 is produced by incorporating an acidic dye or the like in a silicone rubber as a base and vulcanizing it. The uniform developer layer 6 is formed on the developer carrying body 4 by bringing the material 8 of the regulating member 5 into contact with the body 4 with a the contact pressure of ≤30g/cm, and the layer 6 is conveyed to the position opposite to a latent image bearing body 10 by rotation of the body 4, and an electrostatic latent image is developed with the developer attached to the image on the body 10, thus permitting the uniform developer layer to be formed for a long time.
TERAO KAZUO
SHIGEHIRO KIYOSHI
