Patent ID: 8523310
Filing Date: 2013-09-03
Classification: B41J

Abstract:
1. A printing apparatus which prints an image on a printing medium using a print head which discharges ink, the printing apparatus comprising: a conveyance unit having a roller configured to convey the printing medium in a first direction by rotating the roller; a carriage on which the print head is mounted and configured to reciprocate along a second direction which is different from the first direction; a detection unit having an optical sensor mounted on the carriage which is configured to read patterns formed on the printing medium with the print head; an acquisition unit for acquiring relationships between a conveyance amount of the printing medium conveyed by the roller and a rotation amount of the roller by reading the patterns with the optical sensor at a plurality of rotational phases of the roller, wherein the acquisition unit is configured to acquire the relationships at N, N being greater than 2, rotational phases of the roller, each rotational phase being shifted by approximately 360°/N; a setting unit for setting a rotation amount of the roller when printing an image on the printing medium with the print head based on the relationships acquired by the acquisition unit; and a control unit configured to control the apparatus such that when acquiring the relationships the print head prints a first patch, comprised of first and second patterns, the optical sensor reads the printed first patch, the roller rotates a predetermined amount to reach a next rotational phase, the print head prints a second patch, comprised of third and fourth patterns, and the optical sensor reads the printed second patch, wherein an overall rotation of the roller to acquire the relationships is less than one revolution.