| 摘要 |
PURPOSE:To detect the position of an ink drop in a sagittal direction without providing a circuit for calculating the sum of photocurrents, by reading the relative positional difference in the sagittal direction of two ink drops jetted respectively from two nozzles, from a memory. CONSTITUTION:A controller 101 selects from a data memory 111, a table showing the relationship between the relative positional difference in a sagittal direction Y of two ink droplets jetted respectively from two adjacent nozzles and the difference between maximum values of the absolute values of photocurrent differences outputted respectively from a pair of photo-detectors when the two kinds of ink drops pass over the photo-detectors. Then, information indicative of the relative positional difference in the sagittal direction Y of the ink drops, corresponding to information outputted from a subtracting circuit 110, is read. Thereafter, the controller 101 adds the positional difference information to the information on the position in the sagittal direction of the ink drop jetted from the nozzle 37S, thereby calculating the information on the position in the sagittal direction Y of the ink drop jetted from the nozzle 37A. |
