Patent ID: 7108347

Claim:
A method for determining discharging state from each nozzle of a head which discharges liquid droplets, comprising: a driving step of driving each nozzle of the head to discharge liquid droplets; a storage step of detecting a discharging state from each nozzle of the head driven in said driving step and storing the discharging state as a physical amount in a memory; a calculation step of calculating an average value and a standard deviation of the physical amounts stored in the memory in said storage step and obtaining a threshold for determining whether the discharging state from each nozzle of the head is normal or abnormal, on the basis of the average value and the standard deviation; and a determination step of determining whether the discharging state from each nozzle is normal or abnormal, on the basis of the threshold obtained in said calculation step and the physical amount corresponding to the nozzle, wherein in said calculation step, the threshold is obtained by the average value and the standard deviation×N (N=any one of 3, 4, 5 and 6).