To enhance reliability in the measurement of liquid drop ejection characteristics by measuring the positional coordinates of a plurality of nozzle holes at the time of measuring the liquid drop ejection characteristics based on the image of a liquid drop ejected from the nozzle hole of a liquid drop ejecting member and making a decision whether the measurement of positional coordinates of the nozzle holes is erroneous or not.
An image pickup stage is moved to a position where the image of the nozzle hole 2A of a printer head 1 can be picked up ad the positional coordinates X, Z2; Y, Z1 of the nozzle hole 2A are measured based on the image of the nozzle hole 2A (2B, 2C, 2D) picked up by CCD cameras 12X, 12Y mounted on the image pickup stage. α rotational amount, β rotational amount and γ rotational amount for adjusting alignment are then calculated based on the measurements X-Z1 of the positional coordinates of respective nozzle holes 2A-2D. A decision is then made whether all alignment amounts thus calculated are lower than an allowable amount and if all alignment amounts are lower than the allowable amount, a decision is made whether the measurement is erroneous or not based on the positional coordinates of respective nozzle holes.
TAKEMOTO HIROSHI
KANETANI SHISEI
