| 摘要 |
PURPOSE:To detect abnormal ink drop flying accurately without affected by electric noise and prevent the deterioration of print image quality, by providing means detecting optically abnormal ink drop flying. CONSTITUTION:When a jetted ink drop flies along a regular flying path L0, the ink drop interceps light emitted from a light emitting means 1 to a light receiving means 2 during the flight. When it does not, the light from the light emitting means 1 is intercepted differently and the condition of a detection signal S from the light receiving means 2 varies according to a path the ink drop takes. A abnormality decision means 3 decides an abnormal ink drop flying based on the difference between the detection signal S and a reference condition f0 when the regular path L0 is not followed. |
