Patent ID: 9370954
Filing Date: 2016-06-21
CPC Classification: B41J

Claim Text:
1. A method for measuring an amount of positional deviation between recording positions of a plurality of head modules, the method comprising: a recording step of, while relatively moving a recording head with a plurality of head modules each having a plurality of recording elements arranged in a first direction and a recording medium in a second direction orthogonal to the first direction, recording dot patterns having a shape extended in the first direction on the recording medium at intervals determined in advance in the second direction using a first head module and a second head module among the plurality of head modules; a reading step of optically reading the dot patterns recorded on the recording medium in the recording step; a density profile calculation step of calculating a density profile associated with the first head module representing change in density in the second direction of a read image of the dot patterns read in the reading step; a repetition period calculation step of calculating a repetition period of a waveform corresponding to each dot pattern in the density profile based on a calculation result in the density profile calculation step; an integrated density profile calculation step of integrating data of the density profile based on a calculation result of the repetition period calculation step in each repetition period to calculate an integrated density profile associated with the first head module; and a positional deviation amount calculation step of obtaining a peak position of a waveform corresponding to each dot pattern in the integrated density profile based on a calculation result of the integrated density profile calculation step and calculating the amount of positional deviation in the second direction between a recording position of the first head module and a recording position of the second head module based on the peak position and another peak position associated with the second head module.