Patent ID: 8565647

Claim:
An image forming apparatus comprising: a first image bearing member; first code forming means for forming a first electrostatic image code outside a developing zone for a toner image; a second image bearing member; second code forming means for forming a second electrostatic image code outside the developing zone for the toner image; an intermediary transfer member provided with an electrostatic image recording track capable of holding the first electrostatic image code transferred from said first image bearing member to said second image bearing member; transferring means for applying a voltage to a side of said intermediary transfer member which is opposite a side contactable to said first image bearing member to transfer the first electrostatic image code onto said electrostatic image recording track; detecting means including an electroconductive member which is provided in parallel with said electrostatic image code and which is spaced from a surface of said electrostatic image code of the said electrostatic image recording track to be detected with a predetermined gap, and a detecting portion for detecting an induced current generated in said electroconductive member with relative movement relative to lines of said electrostatic image code, said detecting means detecting said first electrostatic image code of the said electrostatic image recording track and said second electrostatic image code of the said second image bearing member at a position of the said second image bearing member; and control means for controlling image formation on said first image bearing member or said second image bearing member on the basis of a detection result of the said detecting means such that the toner image on said second image bearing member is transferred onto said intermediary transfer member and overlaid on the toner image transferred onto said intermediary transfer member from said first image bearing member.