Image forming apparatus

An image forming apparatus comprising:

• an image bearing member;
• a developing device including a carrying member for carrying a one component developer and for developing an electrostatic image formed on said image bearing member with the developer;
• rotatable developer supplying means, contacted to said carrying member, for supplying the developer to said carrying member;
• developer regulating means for regulating an amount of the developer carried on said carrying member;
• a developer supply device for supplying the developer to said developing device;
• developer stirring means for stirring the developer supplied from said developer supply device and for supplying the developer to said developer supplying means;
• and
• control means for controlling a supply of the developer to said developing device from said developer supply device,
• wherein a lower end of a moveable range of said developer stirring means is disposed at a position which is vertically above an upper end of said developer supplying means and which is vertically above a contact portion between said carrying member and said developer regulating means,
• wherein said control means controls said developer supply device such that an upper limit of a height of a surface of the developer is vertically below a wall of an upper surface of said developing device,
• wherein a level of the surface of the developer maintained by said control means is higher than a level which is not lower, in a vertical direction, than a level of the lower end of the moveable range of said developer stirring means by ⅓ of a height between an upper end and the lower end of the moveable range of said developer stirring means, and
• wherein the level of the surface of the developer maintained by said control means is not higher than an upper end of the moveable range of said developer stirring means, and the level of the surface of the developer is higher than the upper end of said developer supplying means and is higher than the contact portion.