CN-113534637-B - Image forming apparatus having a plurality of image forming units

CN113534637BCN 113534637 BCN113534637 BCN 113534637BCN-113534637-B

Abstract

Provided is an image forming apparatus capable of suppressing the spread of the influence of torque fluctuation when a moving mechanism is driven and a gear train capable of transmitting a driving force from a motor to a developing roller. The image forming apparatus includes a YMC moving mechanism that brings a developing roller into contact with and separates from a corresponding photosensitive drum, a K moving mechanism that brings the developing roller into contact with and separates from the photosensitive drum, a developing motor that drives a developing drive gear, a first developing gear train that has a gear that directly meshes with the developing drive gear and is capable of transmitting a driving force to the developing roller, a second developing gear train that has a gear that directly meshes with the developing drive gear and is capable of transmitting a driving force to the developing roller, and a second control gear train that has a gear that directly meshes with the developing drive gear and is capable of transmitting a driving force to the K moving mechanism.

Inventors

IKEGAMI YUSUKE
HARUTA KOTARO
NISHIMURA SHOICHIRO

Assignees

兄弟工业株式会社

Dates

Publication Date: 20260508
Application Date: 20210330
Priority Date: 20200415

Claims (9)

1. An image forming apparatus, comprising: a first photosensitive drum; a second photosensitive drum; a first developing roller movable between a contact position in contact with the first photosensitive drum and a separation position away from the first photosensitive drum; a second developing roller movable between a contact position in contact with the second photosensitive drum and a separation position away from the second photosensitive drum; a first moving mechanism that moves the first developing roller between a contact position in contact with the first photosensitive drum and a separation position away from the first photosensitive drum; A second moving mechanism that moves the second developing roller between a contact position in contact with the second photosensitive drum and a separation position away from the second photosensitive drum; A drive gear; A motor that drives the drive gear; A first gear train having a first gear directly engaged with the driving gear and capable of transmitting a driving force from the motor to the first developing roller; A second gear train provided independently of the first gear train, having a second gear directly engaged with the driving gear and capable of transmitting a driving force from the motor to the second developing roller, and A third gear train which is provided independently of the first gear train and the second gear train, has a third gear directly engaged with the drive gear, and is capable of transmitting a drive force from the motor to at least one of the first moving mechanism and the second moving mechanism, The drive gear is a gear which is provided on an output shaft of the motor and integrally rotates with the output shaft by driving of the motor.
2. The image forming apparatus according to claim 1, wherein, The third gear train is capable of transmitting a driving force from the motor to the first moving mechanism, The image forming apparatus further includes a fourth gear train provided independently of the third gear train, having a fourth gear directly engaged with a gear constituting the second gear train, and capable of transmitting a driving force from the motor to the second moving mechanism.
3. The image forming apparatus according to claim 1, wherein, The third gear train is capable of transmitting a driving force from the motor to both the first moving mechanism and the second moving mechanism.
4. The image forming apparatus according to claim 1, wherein, The third gear train is capable of transmitting a driving force from the motor to the first moving mechanism, The image forming apparatus further includes a fifth gear train provided independently of the third gear train, having a fifth gear directly engaged with the driving gear, and capable of transmitting a driving force from the motor to the second moving mechanism.
5. The image forming apparatus according to any one of claims 1 to 4, comprising: a third photosensitive drum; A fourth photosensitive drum; A third developing roller movable between a contact position in contact with the third photosensitive drum and a separation position away from the third photosensitive drum, and A fourth developing roller movable between a contact position in contact with the fourth photosensitive drum and a separation position away from the fourth photosensitive drum, The first gear train is capable of transmitting a driving force from the motor to the first developing roller and the fourth developing roller, The second gear train is capable of transmitting a driving force from the motor to the second developing roller and the third developing roller.
6. The image forming apparatus according to any one of claims 1 to 4, comprising: a third photosensitive drum; A fourth photosensitive drum; A third developing roller movable between a contact position in contact with the third photosensitive drum and a separation position away from the third photosensitive drum, and A fourth developing roller movable between a contact position in contact with the fourth photosensitive drum and a separation position away from the fourth photosensitive drum, The second gear train is capable of transmitting a driving force from the motor to the second developing roller, the third developing roller, and the fourth developing roller.
7. The image forming apparatus according to any one of claims 1 to 4, comprising: a third photosensitive drum; A fourth photosensitive drum; A third developing roller movable between a contact position in contact with the third photosensitive drum and a separation position away from the third photosensitive drum, and A fourth developing roller movable between a contact position in contact with the fourth photosensitive drum and a separation position away from the fourth photosensitive drum, The second moving mechanism is configured to further move the third developing roller between a contact position in contact with the third photosensitive drum and a separation position away from the third photosensitive drum, and to move the fourth developing roller between a contact position in contact with the fourth photosensitive drum and a separation position away from the fourth photosensitive drum.
8. The image forming apparatus according to claim 5, wherein, The second moving mechanism is configured to further move the third developing roller between a contact position in contact with the third photosensitive drum and a separation position away from the third photosensitive drum, and to move the fourth developing roller between a contact position in contact with the fourth photosensitive drum and a separation position away from the fourth photosensitive drum.
9. The image forming apparatus according to claim 7, wherein, The second developing roller, the third developing roller, and the fourth developing roller are arranged in this order from the upstream toward the downstream in the conveying direction of the sheet, The first developing roller is disposed upstream of the second developing roller or downstream of the fourth developing roller in the conveying direction.

Description

Image forming apparatus having a plurality of image forming units Technical Field The present invention relates to an image forming apparatus including a plurality of photosensitive drums and a plurality of developing rollers. Background Conventionally, there has been known an image forming apparatus including a plurality of photosensitive drums, a plurality of developing rollers movable between a contact position where the photosensitive drums are in contact with the respective photosensitive drums and a separation position where the photosensitive drums are separated from the respective photosensitive drums, a moving mechanism for moving the developing rollers between the contact position and the separation position, and a motor for giving driving force to the developing rollers and the moving mechanism. Further, patent document 1 discloses an image forming apparatus including a first developing gear train that transmits a driving force from a motor to a developing roller for color, a first developing contact/separation gear train that branches from the first developing gear train and transmits a driving force from a motor to a moving mechanism that contacts/separates the developing roller for color, a second developing gear train that transmits a driving force from a motor to a developing roller for monochrome, and a second developing contact/separation gear train that branches from the second developing gear train and transmits a driving force from a motor to a moving mechanism that contacts/separates the developing roller for monochrome. Prior art literature Patent literature Japanese patent application laid-open No. 2016-224418 Technical problem to be solved by the invention However, the present inventors have proposed a configuration in which the developing roller is sequentially separated from the corresponding photosensitive drum after the end of development even during printing in order to extend the life of the developing roller and the toner. In such a configuration, when the conventional driving force transmission mechanism is adopted, there is a concern that the influence of torque fluctuation at the time of driving of the moving mechanism is spread to the gear train, for example, rotation unevenness occurs in gears constituting the gear train, and rotation of the developing roller that is developing is unstable, and image failure occurs. Disclosure of Invention Accordingly, an object of the present invention is to provide an image forming apparatus capable of suppressing an influence of torque fluctuation when a moving mechanism is driven from expanding and a gear train capable of transmitting a driving force from a motor to a developing roller. Technical means for solving the technical problems In order to achieve the above object, an image forming apparatus according to the present invention includes a first photosensitive drum, a second photosensitive drum, a first developing roller movable between a contact position in contact with the first photosensitive drum and a separation position away from the first photosensitive drum, a second developing roller movable between a contact position in contact with the second photosensitive drum and a separation position away from the second photosensitive drum, a first moving mechanism that moves the first developing roller between the contact position and the separation position, a second moving mechanism that moves the second developing roller between the contact position and the separation position, a drive gear, a motor that drives the drive gear, a first gear train, a second gear train, and a third gear train. The first gear train has a first gear directly engaged with the driving gear, and is capable of transmitting a driving force from the motor to the first developing roller. The second gear train is provided independently of the first gear train, has a second gear directly engaged with the drive gear, and is capable of transmitting a driving force from the motor to the second developing roller. The third gear train is provided independently of the first gear train and the second gear train, has a third gear directly engaged with the drive gear, and is capable of transmitting a drive force from the motor to at least one of the first moving mechanism and the second mechanism. According to this configuration, by providing the gear train capable of transmitting the driving force from the motor to the developing roller and the gear train capable of transmitting the driving force from the motor to the moving mechanism independently, the influence of the torque variation at the time of driving the moving mechanism can be suppressed from being spread and the gear train capable of transmitting the driving force from the motor to the developing roller can be suppressed. In the image forming apparatus, the drive gear may be a gear provided on an output shaft of the motor. This reduces the number of gears, thereby enabling a reduction in size and cost