| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device by which a multicolor image is obtained by performing excellent density control by means of accurate density detection by preventing the retransfer of toner to an image carrier when an image pattern for density detection passes through a transfer part on a down stream side. SOLUTION: In forming a continuous image, a transfer material P1 on a transfer belt 12 is positioned at a transfer part TY of yellow which is next to the most upstream transfer part and a transfer material P2 is positioned at a transfer part TC of cyan, and the image pattern GC of cyan transferred to a space between the sheets of paper is positioned at a transfer part TM of magenta, and passes there. Through a magenta toner image is transferred by applying the transfer bias of +600 V at the point of time when the transfer material P2 is positioned at a transfer part TM, the transfer bias is lowered to +200 V for the prevention of the retransfer of the toner or the like when the image pattern GC passes. The transfer bias is similarly lowered from +800 V to +200 V when the image pattern GC of cyan passes the transfer part TY of yellow. Then, the density of the image pattern GC is inspected by a sensor 16. |
