Image forming apparatus, image forming method, and storage medium

A control method for controlling an image forming apparatus,

• the image forming apparatus including,
• a storage device configured to store image data,
• a controller configured to read the image data out of the storage device on a basis of correction information for correcting a print position shift in a sub scanning direction of a first color and a second color,
• a printing unit configured to print an image of the first color and an image of the second color on a basis of the image data read by the controller, and
• a user interface configured to receive an input from a user,
• the control method comprising:
• printing a test image on a sheet on a basis of test image data that includes a plurality of pairs each consisting of an object of the first color and an object of the second color and further includes, for each of the plurality of pairs, identification information for identification of the pair, wherein a position of the object of the second color in relation to the object of the first color differs from said pair to pair;
• receiving, via the user interface, the identification information included in the test image printed on the sheet;
• and
• updating the correction information on a basis of the identification information received.

An image forming apparatus, comprising:

• a storage device configured to store image data;
• a controller configured to read the image data out of the storage device on a basis of correction information for correcting a print position shift in a sub scanning direction of an image of a first color and an image of a second color;
• a printing unit configured to print the image of the first color and the image of the second color on a sheet on a basis of the image data read by the controller;
• and
• a user interface configured to receive information from a user,
• wherein the storage device stores test image data that includes a plurality of objects of a first color arranged in the sub scanning direction, a plurality of objects of a second color each printed at a distance in the sub scanning direction from the corresponding object of the first color, and further includes identification information for identification of the object of the second color each,
• wherein a relative distance between the object of the first color and the object of the second color differs from one object pair to another,
• wherein the controller reads the correction information on a basis of the test image data stored in the storage device,
• wherein the printing unit prints a test image on a basis of the test image data read by the controller,
• wherein the user interface receives the identification information from the user, and
• wherein the controller updates the correction information on a basis of the identification information received via the user interface.