Patent ID: 8123324

Claim:
A method for setting up a condition for a drive signal in a liquid ejection head that includes a plurality of linearly-arranged nozzles and driving elements provided for each of the nozzles, the drive signal being supplied to the driving elements when a liquid is ejected from the nozzles to a receiving medium, the method comprising: calculating an ejection rate for each nozzle relating to a supply of the drive signal under a predetermined condition by using a moving average; classifying the plurality of nozzles into a plurality of groups based on the ejection rate calculated by using the moving average of each nozzle; calculating a proper condition for the drive signal corresponding to each group based on a statistical value of the ejection rate relating to the group; and selecting one proper condition among proper conditions corresponding to the groups so as to set the selected proper condition for each nozzle, wherein in the calculating the ejection rate for each nozzle by using the moving average, the number of the data pieces n used for calculating the moving average with respect to the number of pitches N 1 of the nozzles corresponding to sectioned areas divided at a predetermined distance on the receiving medium is set to n≦N 1 , where n and N 1 are integers and greater than or equal to 2.