Image forming apparatus, method of compensating for error of conveyance distance of recording medium in the same and computer readable medium provided in the same

A method of compensating for an error of a conveyance distance of a recording medium in an image forming apparatus including:

• a feeding roller rotatably disposed to convey the recording medium in a conveying direction, the feeding roller including a rotational axle that is eccentric and a peripheral surface having an actual external dimension that is different from a theoretical external dimension and a peripheral length in the conveyance direction;
• and a recording unit having a head length over which an image can be printed in the conveying direction, the method comprising:
• printing a first image on the recording medium;
• rotating the feeding roller n turns;
• printing a second image on the recording medium after the feeding roller has been rotated n turns;
• rotating the feeding roller (N-0.5) turns from a position at which the feeding roller is when the first image is printed, N being a positive integer;
• printing a third image on the recording medium after the feeding roller has been rotated (N-0.5) turns;
• rotating the feeding roller n turns after the third image has been printed;
• printing a fourth image on the recording medium after the third image has been printed and the feeding roller has been rotated n turns;
• determining a first difference of the actual external dimension from the theoretical external dimension based on both the first image and the second image;
• determining a second difference of the actual external dimension from the theoretical external dimension based on both the third image and the fourth image;
• and
• determining difference of the actual external dimension from the theoretical external dimension based on both the first difference and the second difference.

An image forming apparatus comprising:

• a feeding roller rotatably disposed to convey a recording medium in a conveying direction, the conveying roller including a rotational axle that is eccentric and a peripheral surface having an actual external dimension that is different from a theoretical external dimension and a peripheral length in the conveyance direction;
• a recording unit having a head length over which an image can be printed in the conveying direction;
• a first controller configured to control the recording unit to print a first image on the recording medium;
• and
• a second controller configured to control the feeding roller to rotate N turns, N being a positive integer, and control the recording unit to print a second image on the recording medium after the feeding roller has been rotated N turns.

An image forming apparatus:

• a feeding roller rotatably disposed to convey a recording medium in a conveying direction, the conveying roller including a rotational axle that is eccentric and a peripheral surface having an external dimension that is different from a theoretical external dimension and a peripheral length in the conveyance direction;
• a recording unit having a head length over which an image can be printed in the conveying direction;
• a first controller configured to control the recording head to print a first image on the recording medium;
• a second controller configured to control the feeding roller n turns, and control the recording unit to print a second image on the recording medium after the feeding roller has been rotated n turns;
• a third controller configured to control the feeding roller to rotate (N-0.5) turns from a position at which the feeding roller is when the first image is printed, N being a positive integer, and control the recording unit to print a third image on the recording head after the feeding roller has been rotated (N-0.5) turns;
• and
• a fourth controller configured to control the feeding roller to rotate n turns, and control the recording unit to print a fourth image on the recording medium after the third image has been printed and the feeding roller has been rotated n turns.

A computer readable medium provided in an image forming apparatus including:

• a feeding roller rotatably disposed to convey the recording medium in a conveying direction, the feeding roller including a rotational axle that is eccentric and a peripheral surface having an actual external dimension that is different from a theoretical external dimension and a peripheral length in the conveyance direction;
• and a recording unit having a head length over which an image can be printed in the conveying direction, the computer readable medium comprising:
• a program for printing a first image on the recording medium;
• a program for rotating the feeding roller N turns, N being a positive integer;
• a program for printing a second image on the recording medium after the feeding roller has been rotated N turns;
• and
• a program for determining difference of the actual external dimension from the theoretical external dimension, based on both the first image and the second image.

A computer readable medium in an image forming apparatus including:

• a feeding roller rotatably disposed to convey the recording medium in a conveying direction, the feeding roller including a rotational axle that is eccentric and a peripheral surface having an actual external dimension that is different from a theoretical external dimension and a peripheral length in the conveyance direction;
• and a recording unit having a head length over which an image can be printed in the conveying direction, the computer readable medium comprising:
• a program for printing a first image on the recording medium;
• a program for rotating the feeding roller n turns;
• a program for printing a second image on the recording medium after the feeding roller has been rotated n turns;
• a program for rotating the feeding roller (N-0.5) turns from a position at which the feeding roller is when the first image is printed, N being a positive integer;
• a program for printing a third image on the recording medium after the feeding roller has been rotated (N-0.5) turns;
• a program for rotating the feeding roller n turns after the third image has been printed;
• a program for printing a fourth image on the recording medium after the third image has been printed and the feeding roller has been rotated n turns;
• a program for determining a first difference of the actual external dimension from the theoretical external dimension based on both the first image and the second image;
• a program for determining a second difference of the actual external dimension from the theoretical external dimension based on both the third image and the fourth image;
• and
• a program for determining difference of the actual external dimension from the theoretical external dimension based on both the first difference and the second difference.