| 摘要 |
PROBLEM TO BE SOLVED: To shorten the processing time of recovery operation and to reduce power consumption while improving fluctuation of print density by an arrangement wherein a recovery control means controls ink jet such that a larger quantity of ink is jetted from a jet port for a low jet frequency region than for a high jet frequency region among a plurality of regions. SOLUTION: For example, a black recording head 100 is provided with a plurality of ink jet ports 101 which are divided into region A = 80 nozzles, region B = 80 nozzles, region C = 80 nozzled and region D = 64 nozzles. The number of print dots is counted for each region and the ratio of using dots is managed and then the preliminary jet operation is controlled depending on the count. More specifically, when the count exceeds a predetermined value in any one region of the recording head 100, preliminary jetting is carried out in order to recover the jetting state by varying the number of jetting times, the driving frequency, the jet driving pulse, and the like. Throughput can be enhanced when the preliminary jetting is carried out during paper discharge operation. Insufficient ink jet is dealt with periodically before it takes place thus stabilizing the ink jet operation. |
