| 摘要 |
PROBLEM TO BE SOLVED: To accurately and timely determine the discharge state of each nozzle of an inkjet recording head having a discharge heater generating thermal energy for discharging ink from the nozzles. SOLUTION: Temperature sensors for detecting temperature changes accompanied by the drive of the discharge heater are arranged in the respective nozzles. Inflection points appear in the case that the ink is normally discharged in the temperature change. The sum of the absolute values of differences between the secondary derivatives in each point of temperature data of a predetermined zones including timing when the inflection points appears and the first threshold values based on the secondary derivatives when discharge defects occur is obtained. Because the secondary derivatives do not almost change the sum when the discharge defects occur, the sum when the discharge defects occur is the value closer to zero, and a difference from the time of the normal discharge when the secondary derivatives greatly change before and after the inflection points clearly appear. Thus, it can be determined whether or not the normal discharge is carried out from the size relationship between the sum and the second threshold relating to the sum determined in advance in the respective nozzles. COPYRIGHT: (C)2010,JPO&INPIT |
