| 摘要 |
PROBLEM TO BE SOLVED: To surely detect whether or not ink drops are ejected from all of the nozzles even when using a system wherein a light emitting device and a light receiving device are separated. SOLUTION: Ink drops are sequentially ejected from each nozzle of a head 2 in such a manner that the ink drops block an optical beam which is emitted from a light emitting section 5 and is received by a light receiving section 6 that outputs a signal corresponding to the intensity of the optical beam. The pass-through of the ink drop is detected based on the output signal from the light receiving section 6 so that it is possible to detect whether or not the ink drops are correctly ejected. In the above structure an optical system 9 is provided between the light emitting section 5 and light receiving section 6 and then the diffracted optical beam is collected, thereby improving the detection accuracy. |
