Patent ID: 8369729

Claim:
An image forming apparatus comprising: image forming means for forming a toner image on an image conveying member on the basis of an input image signal; transfer means for transferring the toner image from the image conveying member onto an image receiving member; bias applying means for applying a transfer bias to said transfer means when the toner image is transferred from the image conveying member onto the image receiving member; executing means for executing a test mode in which a test image is formed on the image conveying member and is then transferred onto the image receiving member; detecting means for detecting a current passing through said transfer means in the test mode; control means for controlling an image forming condition of said image forming means on the basis of an output of said detecting means; and setting means for setting a test bias to be applied from said bias applying means at a value larger than the transfer bias in terms of an absolute value, wherein said bias applying means applies the transfer bias so that a transfer efficiency from the image conveying member onto the image receiving member is 90% or more and applies the test bias so that the transfer efficiency from the image conveying member onto the image receiving member is less than 90%.