| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of appropriately setting a delay of a printing sheet by detecting deterioration of a conveyance roller even when there exists variation in speed due to a type difference among printing sheets, a machine difference and a tray difference. <P>SOLUTION: An image forming device 100 disposed on a conveyance path R of a printing sheet comprises: detecting means for detecting an actual printing sheet arrival time t; storage means 24 in which an actual sheet arrival time T for each type of a sheet has been stored in advance; calculating means 27 for calculating a setting time T' for determining deterioration from the actual sheet arrival time T for the each type of the sheet having been stored in the storage means 24; comparing and determining means 23 for comparing and determining the actual printing sheet arrival time t and the setting time T' for determining the deterioration; and deterioration determining means 28 for determining the deterioration by the number of times (n), in which t and T' satisfy an expression of t≥T', having exceeded a preset number of determination times (m) by performing comparison and determination by the comparing and determining means 23 for a predetermined number of times (N) and by counting the number of times (n), in which t and T' satisfy the expression of t≥T'. <P>COPYRIGHT: (C)2012,JPO&INPIT |
