Image forming apparatus operable in two image formation modes using either one developing device or a plurality of developing devices

An image forming apparatus comprising:

• an image bearing member;
• a plurality of developing devices for developing electrostatic images formed on said image bearing member with developers, said developing devices including respective developer carrying members for carrying respective developers;
• moving means for moving a selected one of said developing devices to an operative position, wherein each of said developer carrying members is capable of selectively contacting the developer carried thereon to said image bearing member or spacing the developer carried on said developer carrying member from said image bearing member at the operative position;
• wherein said apparatus is operable in a first image formation mode in which an image is formed using said plurality of developing devices and a second image formation mode in which an image is formed using one of said plurality of developing devices, and wherein the developer carried on said developer carrying member which is at the operative position in the first image formation mode is capable of being spaced from said image bearing member by a first distance during a non-developing-operation, and the developer carried on said developer carrying member which is at the operative position in the second image formation mode is capable of being spaced from said image bearing member by a second distance during the non-developing-operation, and
• wherein the second distance is smaller than the first distance.