Patent ID: 9361551
Filing Date: 2016-06-07
CPC Classification: B41J,G03G,G06K

Claim Text:
1. An image forming apparatus that is capable of forming an image at a plurality of image forming speeds, the image forming apparatus comprising: an image forming unit that has a first image forming part configured to form a first image of a first color and a second image forming part configured to form a second image of a second color different from the first color, and configured to form the image using the first image forming part and the second image forming part; an image bearing member configured to bear the first image and the second image, and to convey the first image and the second image; a controller configured to control the image forming unit to form a measurement image including a first measurement image of the first color and a second measurement image of the second color on the image bearing member; a measurement unit configured to measure the measurement image formed on the image bearing member; a determination unit configured to determine first information related to a relative position of the first measurement image and the second measurement image in a conveyance direction of the image bearing member based on a first measurement result of the measurement image, by the measurement unit, formed by the image forming unit at a first image forming speed, and to determine second information related to a relative position of the first measurement image and the second measurement image in the conveyance direction of the image bearing member based on a second measurement result of the measurement image, by the measurement unit, formed by the image forming unit at a second image forming speed different from the first image forming speed; a generating unit configured to generate correlation data based on the first information and the second information determined by the determination unit; and a correction unit configured to, in a case where the image forming unit forms the image at the first image forming speed, correct a relative position of the first image and the second image in the conveyance direction based on the first information determined by the determination unit, and to, in a case where the image forming unit forms the image at the second image forming speed, correct a relative position of the first image and the second image in the conveyance direction based on the first information determined by the determination unit and the correlation data generated by the generating unit; wherein the controller is further configured to control the image forming unit to form the measurement image at the first image forming speed in a case where a first condition is satisfied, and to control the image forming unit to form the measurement image at both the first image forming speed and the second image forming speed in a case where a second condition is satisfied, and the controller is further configured to, in a case where the first condition is satisfied, determine whether or not the second condition is satisfied before the first condition is satisfied next, and in a case where the second condition is satisfied before the first condition is satisfied next, cause the image forming unit to form the measurement image at both the first image forming speed and the second image forming speed.