Patent ID: 7150511

Claim:
A recording apparatus comprising: a recording section that reciprocates a recording head having a plurality of ink jet nozzles through a carriage to perform bidirectional recording in which forward record and backward record by the recording head are superposed on a recording medium; a check pattern recording section that forms a plurality of check patterns which are different in record position of backward recording relative to forward recording on the recording medium when each check pattern having a plurality of vertical ruled lines is recorded by performing the bidirectional recording with the recording section; a sensor that moves in parallel with a moving direction of the carriage, the sensor including a light-emitting section that emits light toward the recording medium, and a light-receiving section that receives light reflected from the recording medium; a density data detection section that acquires density data indicating degree of light and shade of each check pattern based on the reflected light received by the light-receiving section when the sensor is moved from one end portion to the other end portion of each check pattern; a density amplitude detection section that extracts a plurality of partial data contained in each predetermined partial determination segment from the density data acquired with respect to each of the check patterns, detects a minimum value and a maximum value of the partial data in the partial determination segment, and detects a difference between the minimum value and the maximum value of the partial data as a density amplitude value; an amplitude difference detection section that detects a difference between the density amplitude values of adjacent partial determination segments as an amplitude difference value in each check pattern; a best pattern determination section that judges the amount of variation of the density data in each check pattern based on the amplitude difference values detected by the amplitude difference detection section to determine a check pattern in which the amount of variation of the density data is the smallest in the check patterns as a best check pattern in each check pattern; and a record position setting section that sets record positions of forward recording and backward recording of a check pattern determined to be the best check pattern by the best check pattern determination section as record positions when recording is performed.