| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately predict the degree of progress of deterioration of magnetic carriers in developing devices 8T, 8Y, 8M, 8C, and 8K in a configuration using a premix agent.SOLUTION: Toner supply devices that store a premix agent obtained by mixing a toner and a magnetic carrier are used as toner supply devices 4T, 4Y, 4M, 4C, and 4K. For each of T, Y, M, C, and K, a first index value is calculated as an index value using a first algorithm, and a second index value is calculated as an index value using a second algorithm different from the first algorithm. A control unit 100 is configured to perform processing to determine that the life of the magnetic carrier in the developing devices has been expired on the basis of the fact that at least one of the index values has reached a threshold.</p> |
