| 摘要 |
PROBLEM TO BE SOLVED: To eliminate an influence of laser light on detection of front scattered light from a droplet using the laser light, and to solve the problem that it is difficult to arrange light receiving means at a position where a predetermined light reception output can be obtained and wrong detection is likely to occur.SOLUTION: Defining a region of scattered light where a PD 205 can obtain a predetermined light reception output by receiving the scattered light as a scattered light region 401, a region where laser light 200 is made incident on the PD 205 and the quantity of light incident on the PD 205 exceeds the allowed quantity of light to disable detection as an undetectable region, and the region left after the undetectable region (the region of the laser light 200) is excluded from the scattered region 401 as a detectable region 402, an image formation apparatus includes optical means for expanding the detectable region 402, the optical means shaping the undetectable region by the laser light 200 flat and long in a direction parallel with a nozzle surface of a head and short in a droplet ejection direction in a shape of cross section orthogonal to the ejection direction. |
