US-12619191-B2 - Image forming apparatus including a contact and separation mechanism

US12619191B2US 12619191 B2US12619191 B2US 12619191B2US-12619191-B2

Abstract

An image forming apparatus is provided. The image forming apparatus includes multiple photoreceptors, a primary transfer unit attachable to and detachable from an apparatus main body, and a unit lock that restricts the primary transfer unit from being detached from the apparatus main body. The primary transfer unit includes a primary transfer belt, multiple primary transfer rollers, and a contact and separation mechanism. The contact and separation mechanism includes multiple arm members, a link member, and a grip. When, using the grip, a user moves the link member to a release position for separating all of the primary transfer rollers from the photoreceptors, the unit lock transitions from a lock state to an unlock state.

Inventors

Hiroshi Tachiki

Assignees

SHARP KABUSHIKI KAISHA

Dates

Publication Date: 20260505
Application Date: 20240812
Priority Date: 20230823

Claims (7)

1 . An image forming apparatus comprising: a plurality of photoreceptors; a primary transfer unit attachable to, and detachable from, an apparatus main body; and a unit lock that restricts the primary transfer unit from being detached from the apparatus main body, wherein: the primary transfer unit includes: a primary transfer belt to which toner images are transferred from the plurality of photoreceptors, a plurality of primary transfer rollers that are positioned, respectively, opposite the plurality of photoreceptors, with the primary transfer belt therebetween, and a contact and separation mechanism that brings the plurality of primary transfer rollers into contact with the plurality of photoreceptors and that separates the plurality of primary transfer rollers from the plurality of photoreceptors, and the contact and separation mechanism includes: a plurality of arm members that rotatably support the plurality of primary transfer rollers, respectively, a link member that shifts positions of the plurality of arm members by moving between different positions to bring the plurality of primary transfer rollers into contact with the plurality of photoreceptors and to separate the plurality of primary transfer rollers from the plurality of photoreceptors, the link member being movable back and forth in a direction perpendicular to an axial direction of the plurality of primary transfer rollers, and a grip to move the link member and detach the primary transfer unit from the apparatus main body, the grip being provided at one end of the link member, such that when a user moves, using the grip, the link member to a release position for separating all of the plurality of primary transfer rollers from the plurality of photoreceptors, the unit lock transitions from a locking state to an unlocking state, wherein the unit lock includes a driving-side coupling provided on the apparatus main body and a driven-side coupling provided on the primary transfer unit.
2 . The image forming apparatus according to claim 1 , wherein the link member has a stopper that restricts the unit lock from transitioning from the locking state to the unlocking state, and as the link member moves to the release position, the stopper moves from a restriction position to a restriction release position, the restriction position being a position for restricting the unit lock from transitioning from the locking state to the unlocking state, and the restriction release position being a position for releasing the transition restriction.
3 . The image forming apparatus according to claim 1 , wherein the unit lock has a manual operation knob to manually cause the unit lock to transition from the locking state to the unlocking state.
4 . An image forming apparatus comprising: a plurality of photoreceptors; a primary transfer unit attachable to, and detachable from, an apparatus main body; and a unit lock that restricts the primary transfer unit from being detached from the apparatus main body, wherein: the primary transfer unit includes: a primary transfer belt to which toner images are transferred from the plurality of photoreceptors, a plurality of primary transfer rollers that are positioned, respectively, opposite the plurality of photoreceptors, with the primary transfer belt therebetween, and a contact and separation mechanism that brings the plurality of primary transfer rollers into contact with the plurality of photoreceptors and that separates the plurality of primary transfer rollers from the plurality of photoreceptors, and the contact and separation mechanism includes: a plurality of arm members that rotatably support the plurality of primary transfer rollers, respectively, a link member that shifts positions of the plurality of arm members by moving between different positions to bring the plurality of primary transfer rollers into contact with the plurality of photoreceptors and to separate the plurality of primary transfer rollers from the plurality of photoreceptors, the link member being movable back and forth in a direction perpendicular to an axial direction of the plurality of primary transfer rollers, and a grip to move the link member and detach the primary transfer unit from the apparatus main body, the grip being provided at one end of the link member, such that when a user moves, using the grip, the link member to a release position for separating all of the plurality of primary transfer rollers from the plurality of photoreceptors, the unit lock transitions from a locking state to an unlocking state, wherein the link member has a pusher, the unit lock has a push receiver that is pushed by the pusher, and in conjunction with the user's operation of moving the link member to the release position, the pusher pushes the push receiver to cause the unit lock to transition from the locking state to the unlocking state.
5 . The image forming apparatus according to claim 4 , wherein, when the primary transfer unit is detached from the apparatus main body, the link member is moved to the release position by the user pulling the grip in a direction toward a take-out port of the apparatus main body, such that all of the plurality of primary transfer rollers is shifted to respective separation positions where the plurality of primary transfer rollers is separated from the plurality of photoreceptors, and, after all of the plurality of primary transfer rollers has been shifted to the respective separation positions, the primary transfer unit is detached from the apparatus main body by the user further pulling the grip.
6 . An image forming apparatus comprising: a plurality of photoreceptors; a primary transfer unit attachable to, and detachable from, an apparatus main body; and a unit lock that restricts the primary transfer unit from being detached from the apparatus main body, wherein: the primary transfer unit includes: a primary transfer belt to which toner images are transferred from the plurality of photoreceptors, a plurality of primary transfer rollers that are positioned, respectively, opposite the plurality of photoreceptors, with the primary transfer belt therebetween, and a contact and separation mechanism that brings the plurality of primary transfer rollers into contact with the plurality of photoreceptors and that separates the plurality of primary transfer rollers from the plurality of photoreceptors, the contact and separation mechanism includes: a plurality of arm members that rotatably support the plurality of primary transfer rollers, respectively, a link member that shifts positions of the plurality of arm members by moving between different positions to bring the plurality of primary transfer rollers into contact with the plurality of photoreceptors and to separate the plurality of primary transfer rollers from the plurality of photoreceptors, the link member being movable back and forth in a direction perpendicular to an axial direction of the plurality of primary transfer rollers, and a grip to move the link member and detach the primary transfer unit from the apparatus main body, the grip being provided at one end of the link member, such that when a user moves, using the grip, the link member to a release position for separating all of the plurality of primary transfer rollers from the plurality of photoreceptors, the unit lock transitions from a locking state to an unlocking state, and the unit lock includes: a locking hole provided in the apparatus main body, a lock pin provided on the primary transfer unit, the lock pin being movable back and forth to be engaged with the locking hole, and an urging member that urges the lock pin in such a direction as to separate the lock pin from the locking hole, wherein in conjunction with the user's operation of moving the link member to the release position, the urging member exerts an urging force to cause the unit lock to transition from the locking state to the unlocking state.
7 . The image forming apparatus according to claim 6 , wherein, when the primary transfer unit is detached from the apparatus main body, the link member is moved to the release position by the user pulling the grip in a direction toward a take-out port of the apparatus main body, such that all of the plurality of primary transfer rollers is shifted to respective separation positions where the plurality of primary transfer rollers is separated from the plurality of photoreceptors, and, after all of the plurality of primary transfer rollers has been shifted to the respective separation positions, the primary transfer unit is detached from the apparatus main body by the user further pulling the grip.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority from Japanese Application JP2023-135341, the content of which is hereby incorporated by reference into this application. BACKGROUND OF THE INVENTION 1. Field of the Invention The present disclosure relates to an image forming apparatus and particularly to, for example, an image forming apparatus including a plurality of photoreceptors and a primary transfer unit attachable to and detachable from an apparatus main body. 2. Description of the Related Art Some examples of conventional image forming apparatuses are known. An image forming apparatus according to related art has a belt unit (primary transfer unit) including: a belt member (primary transfer belt) to which toner images on image carriers (photoreceptors) are transferred, and that is stretched around a plurality of stretching members; transfer members (primary transfer rollers) that transfer the toner images from the image carriers to the belt member; and a position shifting member (contact and separation mechanism) that shifts each transfer member between a contact position where the transfer member makes contact with the corresponding image carrier with the belt member therebetween and a separation position where the transfer member is separated from the corresponding image carrier. The belt unit is attachable to and detachable from an apparatus main body through an opening in a housing of the apparatus main body in a direction perpendicular to an axial direction of the stretching members. This image forming apparatus further has an operation lever provided on an outer side surface of the housing in a manner such that an engagement part of the position shifting member and a mating engagement part of the operation lever can be engaged and disengaged in the axial direction of the stretching members. The operation lever is shiftable between predetermined first and second positions. The operation lever is used to operate the position shifting member so that the transfer members come to the respective contact positions when the operation lever is in the first position and the transfer members come to the respective separation positions when the operation lever is in the second position. SUMMARY OF THE INVENTION In the related art, the primary transfer rollers are shifted between the positions where the primary transfer rollers make contact with the photoreceptors with the primary transfer belt therebetween (contact positions) and the positions where the primary transfer rollers are separated from the photoreceptors (separation positions) using the contact and separation mechanism that is operated by moving the operation lever. However, the related art is inconvenient because the operation for contact and separation of the primary transfer rollers using the operation lever and an operation for removal of the primary transfer unit need to be performed separately. The related art is inconvenient also because a user can wrongly detach the primary transfer unit with the primary transfer rollers in the contact positions, which can damage other components such as the photoreceptors and the primary transfer belt. It is therefore a main object of the present disclosure to provide a novel image forming apparatus. Another object of the present disclosure is to provide an image forming apparatus that can reliably keep the primary transfer belt separated from the photoreceptors when the primary transfer unit is detached from the apparatus main body. An image forming apparatus according to a first aspect of the present disclosure includes: a plurality of photoreceptors; a primary transfer unit attachable to and detachable from an apparatus main body; and a unit lock that restricts the primary transfer unit from being detached from the apparatus main body. The primary transfer unit includes a primary transfer belt to which toner images are transferred from the plurality of photoreceptors, a plurality of primary transfer rollers opposed to the respective photoreceptors with the primary transfer belt therebetween, and a contact and separation mechanism that brings the primary transfer rollers into contact with the photoreceptors and separates the primary transfer rollers from the photoreceptors. The contact and separation mechanism includes a plurality of arm members, a link member, and a grip to move the link member and detach the primary transfer unit from the apparatus main body. The arm members rotatably support the respective primary transfer rollers. The link member shifts positions of the arm members by moving between different positions to bring the primary transfer rollers into contact with the photoreceptors and separate the primary transfer rollers from the photoreceptors. The link member is movable back and forth in a direction perpendicular to an axial direction of the primary transfer rollers. The grip is provided at one end of the link member. In conjunction with the user's ope