A correction method for correcting misalignment between landing positions of ink ejected in a printing device that performs printing by an inkjet method,
- wherein the printing device includes
- an inkjet head that ejects ink,
- a carriage on which the inkjet head is mounted,
- a carriage drive mechanism that moves the inkjet head together with the carriage by moving the carriage in a predetermined main scanning direction, and
- a detection mechanism that detects a concentration of a correction pattern which is a pattern used for correction the misalignment between the landing positions of the ink ejected from the inkjet head, and
- the correction method comprises
- causing the inkjet head to print the correction pattern by controlling operations of the carriage drive mechanism and the inkjet head and correcting the misalignment between the landing positions based on the concentrations of the correction pattern detected by the detection mechanism,
- providing, when one side in the main scanning direction is defined as a first direction side and the other side in the main scanning direction is defined as a second direction side, the correction pattern that is a pattern for correcting misalignment between a landing position of the ink ejected from the inkjet head when the carriage moves to the first direction side and a landing position of the ink ejected from the inkjet head when the carriage moves to the second direction side and includes a plurality of first direction patterns which are a plurality of patterns printed by the inkjet head when the carriage moves to the first direction side and a plurality of second direction patterns which are a plurality of patterns printed by the inkjet head when the carriage moves to the second direction side,
- arraying the plurality of first direction patterns and the plurality of second direction patterns such that an overlapping method of the first direction pattern and the second direction pattern is different depending on positions in the main scanning direction by arraying the plurality of first direction patterns at a regular interval in the main scanning direction and arraying the plurality of second direction patterns at a regular interval in the main scanning direction wider than the interval between the first direction patterns,
- changing the concentrations of the correction pattern detected by the detection mechanism depending on the positions in the main scanning direction by changing the overlapping method of the first direction pattern and the second direction pattern depending on the positions in the main scanning direction, and
- detecting a position where the concentration is the highest among the concentrations of the correction pattern changing depending on the positions in the main scanning direction, calculating magnitude of the misalignment between the landing position of the ink ejected from the inkjet head when the carriage moves to the first direction side and the landing position of the ink ejected from the inkjet head when the carriage moves to the second direction side based on a detection result of the position where the concentration is the highest, and correcting the misalignment between the landing positions based on a calculation result of the magnitude of the misalignment,
- wherein changing the concentrations of the correction pattern such that the concentration is the lowest at a position where the first direction pattern and the second direction pattern overlap with each other with positions in the main scanning direction aligned and the concentration is the highest at a position where the first direction pattern and the second direction pattern overlap with each other with the positions in the main scanning direction misaligned.