| 摘要 |
PROBLEM TO BE SOLVED: To restrict an increase in consumption amount of ink as much as possible by recovering an ink drop speed only when it is necessary on the basis of the measured result of the ink drop speed. SOLUTION: A time T from an output decrease (ta) of a light-receiving element 40b to an output decrease (tb) of a light-receiving element 40d is measured, and a distance Ds between two optical axes is divided by the time T, whereby a fly speed of ink drops is obtained. The obtained fly speed is compared with a predetermined threshold value. When the fly speed is not higher than the threshold value, a position of a selected nozzle is stored. One nozzle is selected from stored nozzles (nozzles of a low fly speed of ink drops) to be subjected to normal flushing. Thereafter, the fly speed of ink drops is measured so as to inspect whether or not ink drops are recovered in speed. The measured value is compared with the predetermined threshold value. When the measured value is larger than the threshold value, a maintenance work to the nozzle is terminated. On the other hand, when the measured value is smaller than the threshold value, the nozzle is subjected to power flushing. |
