Patent attributes
A light detection device includes laser sources arranged at both ends in the scanning direction and at one end in the paper feed direction for emitting laser beams intersecting with each other, and light receiving elements arranged at both ends in the scanning direction and at the other end in the paper feed direction for receiving the laser beams emitted from the laser sources. An ink-jet head is adapted to be capable of reciprocating in the scanning direction, and a plurality of nozzle ejection ports are formed between the laser sources and the light-receiving elements in terms of paper feed direction. When ink drops ejected from a nozzle are overlapped with the laser beams, the laser beams are interrupted by the ink drops, and hence the light-receiving elements do not receive the laser beams any longer. The detection of these light beams may be used to determine an amount of deviation in liquid drops ejected from the nozzles, and corrective measures may be taken.
