| 摘要 |
PURPOSE:To enhance the detection accuracy of a flying ink droplet, by detecting the position of the flying ink droplet in an up-and-down direction on the basis of the positions of some points imparting no effect of various parameters in the horizontal direction and the spatial positional relation between a light source part and a light receiving means. CONSTITUTION:A plurality of sensors 30 each consisting of a light source part 10 and a pair of light receiving means 20 opposed thereto are arranged in front of a plurality of nozzles 1 in a row along the arrangement direction of the nozzles 1. The output difference between a pair of the light receiving means 2 of each sensor 30 is calculated while the voltage for charging ink is changed to successively change the deflection quantity of the ink flying from each nozzle 1. The charge voltage value at the point of time when said output difference takes a predetermined state is calculated and, on the basis of said voltage value, the coordinates position of the point, where the boundary surface of the detection region of the sensor 30 and the outside of said region crosses the deflection locus of the ink, in the horizontal direction is calculated and, on the basis of said position and the spatial coordinates position of the boundary surface, the position relating to the up-and-down direction of the ink is detected. By this method, the position of the flying ink droplet in the up-and-down direction can be detected with sufficient accuracy. |
