Image forming apparatus, and method and computer-readable medium therefor

A method implementable on a processor coupled with an image forming apparatus comprising a conveyor and an image former, the method comprising:

• controlling the image former to form a first pattern element on a recording medium;
• after the first pattern element is formed, controlling the conveyor to rotate by a first amount and convey the recording medium with the first pattern element formed thereon over a particular distance corresponding to the first amount in a conveyance direction;
• after the first pattern element formed on the recording medium is conveyed over the particular distance in the conveyance direction in response to the conveyor rotating by the first amount, controlling the image former to form a second pattern element to be paired with the first pattern element formed on the recording medium thereby forming a first test pattern, and form an unpaired first pattern element, the first test pattern comprising the pair of the first pattern element and the second pattern element;
• after the unpaired first pattern element is formed, each time the unpaired first pattern formed on the recording medium is conveyed over the particular distance in the conveyance direction in response to the conveyor rotating by the first amount, controlling the image former to form another second pattern element to be paired with the unpaired first pattern element thereby forming another first test pattern;
• controlling the image former to form a third pattern element on the recording medium;
• after the third pattern element is formed, controlling the conveyor to rotate by a second amount and convey the recording medium with the third pattern element formed thereon over a specific distance corresponding to the second amount in the conveyance direction, wherein the second amount is different from the first amount, and at least one of the first amount and the second amount is a non-integer multiple of a rotation amount of the conveyor that makes a single rotation;
• after the third pattern element formed on the recording medium is conveyed over the specific distance in the conveyance direction in response to the conveyor rotating by the second amount, controlling the image former to form a fourth pattern element to be paired with the third pattern element formed on the recording medium thereby forming a second test pattern, and form an unpaired third pattern element, the second test pattern comprising the pair of the third pattern element and the fourth pattern element;
• and
• after the unpaired third pattern element is formed, each time the unpaired third pattern formed on the recording medium is conveyed over the specific distance in the conveyance direction in response to the conveyor rotating by the second amount, controlling the image former to form another fourth pattern element to be paired with the unpaired third pattern element thereby forming another second test pattern.

A non-transitory computer-readable medium storing computer-readable instructions executable on a processor coupled with an image forming apparatus comprising a conveyor and an image former, the instructions being configured to, when executed by the processor, cause the processor to:

• control the image former to form a first pattern element on a recording medium;
• after the first pattern element is formed, control the conveyor to rotate by a first amount and convey the recording medium with the first pattern element formed thereon over a particular distance corresponding to the first amount in a conveyance direction;
• after the first pattern element formed on the recording medium is conveyed over the particular distance in the conveyance direction in response to the conveyor rotating by the first amount, control the image former to form a second pattern element to be paired with the first pattern element formed on the recording medium thereby forming a first test pattern, and form an unpaired first pattern element, the first test pattern comprising the pair of the first pattern element and the second pattern element;
• after the unpaired first pattern element is formed, each time the unpaired first pattern formed on the recording medium is conveyed over the particular distance in the conveyance direction in response to the conveyor rotating by the first amount, control the image former to form another second pattern element to be paired with the unpaired first pattern element thereby forming another first test pattern;
• control the image former to form a third pattern element on the recording medium;
• after the third pattern element is formed, control the conveyor to rotate by a second amount and convey the recording medium with the third pattern element formed thereon over a specific distance corresponding to the second amount in the conveyance direction, wherein the second amount is different from the first amount, and at least one of the first amount and the second amount is a non-integer multiple of a rotation amount of the conveyor that makes a single rotation;
• after the third pattern element formed on the recording medium is conveyed over the specific distance in the conveyance direction in response to the conveyor rotating by the second amount, control the image former to form a fourth pattern element to be paired with the third pattern element formed on the recording medium thereby forming a second test pattern, and form an unpaired third pattern element, the second test pattern comprising the pair of the third pattern element and the fourth pattern element;
• and
• after the unpaired third pattern element is formed, each time the unpaired third pattern formed on the recording medium is conveyed over the specific distance in the conveyance direction in response to the conveyor rotating by the second amount, control the image former to form another fourth pattern element to be paired with the unpaired third pattern element thereby forming another second test pattern.