Oki Data Infotech Corporation

Yoshihisa Aoi

A recording apparatus includes a recording head having nozzles ejecting ink onto a recording medium, a conveying unit that conveys the recording medium, and a carriage. A sensor is mounted on the carriage for detecting image density. A detection controller that performs control to record test patterns on the recording medium and read densities of the test patterns using the sensor to thereby detect a non-ejection nozzle of the recording head. The test patterns are formed by recording a line including a predetermined number of dots in predetermined areas for respective nozzles every plurality of times of conveyance of the recording medium. The detection controller reads the test patterns using the sensor, calculates a position of a non-recorded portion in the test patterns, and specifies a position of the non-ejection nozzle based on the calculated position of the non-recorded portion and positions of the nozzles that record the test patterns.

Recording apparatus

When an inkjet printer ejects ink onto a recording medium on a go path and on a return path of a carriage, if ink cannot be ejected onto the same position on the go path and on the return path, image quality becomes poor. Test patterns with shifted ejection timing are hitherto recorded on the recording medium, and appropriate timing is input as a correction value. There is also an inkjet printer which automatically reads a test pattern, but the test pattern is recorded without consideration of a state of a head, and thus, accuracy is low. Therefore, a test pattern having a long period and a test pattern having a short period are recorded, and densities of the test patterns are read by a sensor. An extremum candidate is determined from the test pattern having a long period, and rough adjustment is made first. Then, in a region around the extremum, an extremum is determined from the test pattern having a short period. An extremum corresponding to a period to which the extrema of the two test patterns belong is set as a correction value. By determining ejection timing of the recording head using the correction value, an image in which dot deviation between the go path and the return path is inhibited can be recorded.

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Chiba, Japan

Yoshihisa Aoi