| 摘要 |
PROBLEM TO BE SOLVED: To obtain nearly the same detection output level by reducing effects of optical diffraction for all nozzles in one nozzle array, and to carry out stable detection of nozzles. SOLUTION: There are provided a light emitting means for ejecting a detection light to intersect a trajectory of ink droplets discharged from the nozzles of a recording head, a light receiving means for detecting whether or not the ink droplets pass in an optical path of the detection light by receiving the detection light, a discharge control means for controlling to discharge the ink droplets sequentially in time series towards the optical path of the detection light from all of the nozzles of the recording head, and a discharge defective nozzle specifying means for specifying discharge defective nozzles by detecting a discharge state of the ink droplets from the nozzles on the basis of a timing of discharging of the ink droplets by the discharge control means and a passage detection timing of the ink droplets by the light receiving means. The discharge control means can change the number of ink droplets discharged from each nozzle at the time of detection, and also controls nozzles of the light emitting means side to discharge more as compared with nozzles of the light receiving means side so that an output level by the light receiving means becomes nearly the same for all nozzles on the optical path of the detection light. COPYRIGHT: (C)2006,JPO&NCIPI
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