Image forming apparatus having transfer member for carrying a recording medium

An image forming apparatus, comprising:

• an image bearing member for bearing an image;
• image forming means for forming images of a plurality of colors on said image bearing member;
• a recording material bearing member for bearing and feeding a recording material;
• a transfer member brought into contact with a back surface of said recording material bearing member to induce charges to said recording material bearing member so that an image on said image bearing member is electrostatically transferred to the recording material;
• and
• constant-current-controlling means for controlling a power supply so that a predetermined electric current is supplied to said transfer member,
• wherein the images of the plurality of colors formed on said image bearing member are sequentially superimposed on the recording material borne by said recording material bearing member, and
• wherein the following relationship is held:
• 900≦V·(S·L)/I≦4500(kV·mm2/μC)
• where
• I (μC/sec.) denotes said predetermined electric current,
• V (kV) denotes an applied voltage of said power supply when said predetermined electric current I is supplied,
• S (mm/sec.) denotes a movement speed of said recording material bearing member, and
• L (mm) denotes a length of said transfer member in a direction perpendicular to a feeding direction of the recording material.