| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of properly detecting an abnormal state of the apparatus and to provide its control method. <P>SOLUTION: When an amount of toner remaining in a developing unit is relatively large, a control target value for the amount of toner is set to Ttgt1 and also the lower limit of the amount of toner, which is considered to be proper, is set to TL1. When the density of a patch image formed under specific conditions does not satisfy the minimum guaranteed density Dma, it is judged that the apparatus is in an abnormal state. When an amount of toner remaining in the development unit decreases, the characteristic of toner in the development unit changes. Therefore, the control target value and the lowest limit are altered to Ttgt2 and TL2, respectively, in order to correspond to the changes. Thus, the image density and the minimum guaranteed density after the control are made stable. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
