摘要 |
PURPOSE: To effectively detect the discharge amount of ink by small ink consumption even if the accuracy of a unit for aligning an optical path with a head for discharging the ink is not so high in an optical discharge failure detecting structure for detecting the discharge failure of an ink jet head according to the number of ink droplets for shutting OFF the path. CONSTITUTION: When a power source is turned ON (step S1), a home position is detected (step S2), a carriage is moved from this point at a predetermined speed, and ink is continuously discharged at zones P1 to P2 capable of existing a photosensor (step S3). The number S of steps of a motor to the time point of the maximum output Vmax of the output change of the photosensor according to the continuous ink discharge is obtained (step S5), and then the ink is discharged in the following discharge failure detecting processes (steps S9 to S14). |