| 摘要 |
PURPOSE:To detect emitting abnormality, by providing an apparatus for irradiating the energy acting part of a liquid flowline from the outside of a liquid flowline constituting member and an apparatus for receiving light irradiated from a light irradiating apparatus through the energy acting part. CONSTITUTION:A recording head 1 is irradiated with light in the vicinity of the energy acting part 13 thereof through a top plate 16 comprising a light pervious member prior to emitting liquid droplets by a light irradiating apparatus 6 and the reflected light therefrom is detected by a light receiving apparatus 7. Therefore, when there are no air bubbles at all in the vicinity of the energy acting part 13 of a liquid flowline 11, the greater part of irradiated light passes the liquid in the liquid flowline 11 and detected as reflected light by the light receiving apparatus 7. On the other hand, when air bubbles are present in the vicinity of the energy acting part 13, light is reflected from the boundary surface of the liquid and air bubbles in the liquid flowline 11 and detected by the light receiving apparatus 7. |
