| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing a detection error of a toner adhesion amount, caused by fluctuations in a base portion output Vsg of an optical sensor, by a simple method in the detection of the toner adhesion amount upon carrying out an image density control. <P>SOLUTION: A toner image detection sensor 310 and an optical sensor-counter roller 311, which opposes to the toner image detection sensor 310 via an intermediate belt 10, are disposed in a downstream side along a rotation direction of the intermediate transfer belt 10 and in an upstream side of a secondary transfer position in each image forming unit 18, so as to detect a toner density of a pattern portion in a toner pattern of each color formed on the intermediate transfer belt 10. The output of the sensor is converted into a toner adhesion amount based on a relational formula between a toner adhesion amount and a ratio (Vsp/Vsg) of a pattern portion output Vsp detected by the toner image detection sensor 310 to a base portion output Vsg detected just before (or immediately after) detecting the pattern portion. <P>COPYRIGHT: (C)2012,JPO&INPIT |
