| 摘要 |
PROBLEM TO BE SOLVED: To detect clogging of nozzle by a low cost ink ejection detector without using an ejection detector having a high sensitivity by a method wherein the ink ejection detector is disposed by being inclined at a predetermined angle with respect to arrangement of head nozzles, then a light shading area of a sensor is sufficiently attained so that the sensitivity can be improved and it is possible to correspond to any number of nozzles and density thereof even when they are raised. SOLUTION: There is disclosed an ink jet recorder comprising a carriage constituted such that it is reciprocated relatively with a recording medium and a print head 1 which is mounted on the carriage and comprises a plurality of nozzle arrays 2 that eject ink drops. The ink jet recorder comprises a pair of photodetectors 3, 4 that scan the nozzle array in the arrangement direction at a predetermined inclination angleθx in the clockwise direction or counter clockwise direction around a center of the nozzle array. As a result, even when the number of nozzles is increased because of the high resolution of the nozzles, it is possible to accurately detect ink ejection without using an ejection detector having a high sensitivity. |
