Patent ID: 8911055

Claim:
A dot position measurement method, comprising: a line pattern forming step of forming a measurement line pattern including a plurality of lines of rows of dots corresponding to a plurality of recording elements arranged in a first direction of a recording head respectively, on a recording medium, while causing relative movement between the recording head and the recording medium in a second direction perpendicular to the first direction, the measurement line pattern including a plurality of line blocks respectively including a group of the lines recorded by the recording elements spaced at a prescribed interval in the first direction, and a plurality of common line blocks respectively including the lines recorded by the recording elements which are same as the recording elements recording the lines included in the plurality of line blocks respectively; a reading step of reading an image of the measurement line pattern formed on the recording medium in the line pattern forming step, by an image reading apparatus; a line position measurement step of measuring positions of the lines included in the plurality of line blocks and the plurality of common line blocks, from the image of the measurement line pattern read by the image reading apparatus; an averaging step of determining average values with respect to the recording elements, each of the average values being an average value of measurement values of positions of the lines recorded by a same one of the recording elements and included in a same one of the plurality of common line blocks; and a line position correction step of correcting the measurement values of the positions of the lines according to the average values.