| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of detecting the abnormality of a toner residual amount detection part and detecting the abnormality of a patch pattern image reading means according to the transition of a density variation value. <P>SOLUTION: When continuously detecting that the density variation value of a toner pattern image exceeds a predetermined value (α) two or more times and if a difference between the first density variation value and the second density variation value obtained after the first density variation value is smaller than a predetermined value (β), the image forming apparatus judges that the pattern reading means is abnormal. <P>COPYRIGHT: (C)2008,JPO&INPIT |
