US 12,228,870 B2
Image-forming apparatus provided with photosensitive drums, developing rollers and fixing device and forming both multicolor image and single-color image preliminary
Sadaharu Kato, Kariya (JP)
Assigned to BROTHER KOGYO KABUSHIKI KAISHA, Nagoya (JP)
Filed by BROTHER KOGYO KABUSHIKI KAISHA, Nagoya (JP)
Filed on Feb. 7, 2023, as Appl. No. 18/165,432.
Claims priority of application No. 2022-033485 (JP), filed on Mar. 4, 2022.
Prior Publication US 2023/0280683 A1, Sep. 7, 2023
Int. Cl. G03G 15/22 (2006.01); G03G 15/00 (2006.01); G03G 15/20 (2006.01)
CPC G03G 15/205 (2013.01) [G03G 15/6564 (2013.01); G03G 15/757 (2013.01); G03G 2215/2074 (2013.01)] 12 Claims
OG exemplary drawing
 
1. An image-forming apparatus comprising:
a sheet tray configured to accommodate a sheet therein;
a pickup roller configured to feed the sheet from the sheet tray;
a belt configured to move in a first direction, the belt being used when a developer image is transferred onto the sheet;
a first photosensitive drum rotatable about an axis extending in a second direction, the first photosensitive drum being in contact with the belt at a first position;
a second photosensitive drum rotatable about an axis extending in the second direction, the second photosensitive drum being in contact with the belt at a second position positioned downstream of the first position in the first direction;
a first developing roller movable between a position in which the first developing roller is in contact with the first photosensitive drum and a position in which the first developing roller is separated from the first photosensitive drum;
a second developing roller movable between a position in which the second developing roller is in contact with the second photosensitive drum and a position in which the second developing roller is separated from the second photosensitive drum;
a fixing device configured to fix the developer image transferred on the sheet; and
a controller configured to perform:
(a) raising, by causing the fixing device to generate heat, a temperature of the fixing device up to a fixing temperature; and
(b) causing the first photosensitive drum and the second photosensitive drum to rotate and causing the belt to move in the first direction,
wherein the controller is configured to further perform:
in a case where the controller performs forming a multicolor image on the sheet:
(c) bringing, in response to the temperature of the fixing device reaching a first temperature lower than the fixing temperature, the first developing roller into contact with the first photosensitive drum and the second developing roller into contact with the second photosensitive drum; and
(d) feeding, after a first period of time elapses from a time when the temperature of the fixing device reaches the first temperature, the sheet from the sheet tray toward the belt using the pickup roller; and
in a case where the controller performs forming a single-color image on the sheet:
(e) bringing, after a second period of time elapses from the time when the temperature of the fixing device reaches the first temperature, the second developing roller into contact with the second photosensitive drum; and
(f) feeding, after the first period of time elapses from the time when the temperature of the fixing device reaches the first temperature, the sheet from the sheet tray toward the belt using the pickup roller, and
wherein the second period of time is longer than the first period of time.