US 12,296,578 B2
Image forming apparatus and method to adjust amount of sheet medium between upstream roller and downstream roller in conveyance direction
Gakuro Kanazawa, Toyokawa (JP); Taisei Okuzono, Nagoya (JP); Yushi Deura, Nagoya (JP); Yasuhiro Nakano, Nagoya (JP); Haruka Azechi, Nagoya (JP); and Yuki Tsujimura, Nagoya (JP)
Assigned to Brother Kogyo Kabushiki Kaisha, Nagoya (JP)
Filed by BROTHER KOGYO KABUSHIKI KAISHA, Nagoya (JP)
Filed on Dec. 22, 2022, as Appl. No. 18/145,285.
Claims priority of application No. 2021-211430 (JP), filed on Dec. 24, 2021; and application No. 2022-202540 (JP), filed on Dec. 19, 2022.
Prior Publication US 2023/0202208 A1, Jun. 29, 2023
Int. Cl. B41J 11/00 (2006.01); B41J 2/21 (2006.01); B41J 11/66 (2006.01); B41J 29/393 (2006.01)
CPC B41J 11/007 (2013.01) [B41J 2/2132 (2013.01); B41J 11/0055 (2013.01); B41J 29/393 (2013.01); B41J 11/663 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An image forming apparatus comprising:
a sheet medium storage configured to accommodate a sheet medium;
a first roller configured to feed, from the sheet medium storage, the sheet medium in a conveyance direction along a conveyance path;
a second roller disposed downstream of the first roller in the conveyance direction, the second roller being configured to convey the sheet medium fed by the first roller in the conveyance direction along the conveyance path;
a print engine disposed downstream of the second roller in the conveyance direction, the print engine being configured to form an image on the sheet medium conveyed by the second roller; and
a controller configured to:
perform one or more times a first image forming process that comprises:
causing the print engine to perform image formation on the sheet medium; and
conveying the sheet medium in the conveyance direction by rotating the first roller by a first number of rotations and rotating the second roller by a second number of rotations smaller than the first number of rotations; and
when a count of times the first image forming process has been performed becomes a particular number of times, perform a second image forming process that comprises:
causing the print engine to perform image formation on the sheet medium; and
conveying the sheet medium in the conveyance direction by rotating the first roller by a third number of rotations smaller than the first number of rotations and rotating the second roller by the second number of rotations;
wherein the controller is further configured to:
perform skew correction to cause the first roller to feed the sheet medium in a state where a leading end of the sheet medium is in contact with the second roller;
after the skew correction, perform initial sheet placement to cause the first roller and the second roller to feed the sheet medium by a particular feed amount by rotating the first roller by a smaller number of rotations than the second roller;
set an initial value based on a feed amount of the sheet medium fed by the first roller during the skew correction, and a difference in the number of rotations between the first roller and the second roller in the initial sheet placement;
after the initial sheet placement, repeatedly perform the first image forming process a plurality of times, wherein each time the first image forming process is performed, the controller cumulatively adds to the initial value a difference value obtained by subtracting the second number of rotations from the first number of rotations, thereby obtaining an accumulated value; and
when the accumulated value exceeds a threshold, perform the second image forming process.