JP-7855901-B2 - Image forming apparatus

JP7855901B2JP 7855901 B2JP7855901 B2JP 7855901B2JP-7855901-B2

Inventors

池野雄一

Assignees

ブラザー工業株式会社

Dates

Publication Date: 20260511
Application Date: 20220401

Claims (14)

A fuser for fixing a toner image transferred to a conveyed sheet, comprising: a heating member; a pressurizing member that nips the sheet together with the heating member; a fuser frame covering the heating member and the pressurizing member, with an opening formed on the upstream side of the heating member in the sheet conveying direction; and a shutter that moves between a closed position that closes the opening and an open position that opens the opening. An opening/closing link connected to the shutter, which moves the shutter between the open position and the closed position, Equipped with, The fixing frame has a first contact surface against which the shutter in the closed position contacts, The opening/closing link is movable in a first direction that moves the shutter to the closed position and in a second direction that moves the shutter to the open position. An image forming apparatus characterized in that, when the shutter is in contact with the first contact surface and in the closed position, movement of the opening/closing link in the first direction is permitted while the shutter is maintained in the closed position.
The image forming apparatus according to claim 1, wherein the first contact surface of the fixing frame faces the upstream side in the sheet transport direction.
The aforementioned open/close link is A shutter link connected to the shutter, which moves the shutter between the open position and the closed position, A link cam connected to the shutter link and movable in the first and second directions, The system includes a spring that moves along the movement of the link cam and presses against the shutter link, When the shutter is in the closed position, in contact with the first contact surface, The spring contacts the shutter link and presses the shutter link in the first direction. The image forming apparatus according to claim 1 or claim 2, wherein the movement of the link cam in the first direction is permitted by the elastic deformation of the spring while the shutter remains in the closed position.
The shutter has a pivot shaft that is rotatably supported by the fixing frame and a connecting shaft that protrudes in a direction parallel to the pivot shaft. The image forming apparatus according to claim 3, wherein the shutter link is connected to the connecting shaft.
The shutter link has an elongated hole, The image forming apparatus according to claim 4, wherein the connecting shaft of the shutter is located within the elongated hole.
The device comprises a main body that houses the aforementioned fuser, The link cam comprises a link cam body having a through hole that penetrates along the rotation axis direction and is rotatably supported on the fixing frame, and a projection that protrudes from the link cam body along the rotation axis direction, The shutter link has a boss that protrudes along the rotation axis direction and is located within the through hole, The image forming apparatus according to claim 3, wherein the apparatus body has a body-side link that engages with the projection and moves the link cam.
The shutter link and the link cam are rotatably supported on the fixing frame in the same axis. The spring is a coil spring having a coil supported by the link cam body and a spring arm extending outward from the coil. The spring arm is located inside the through hole, The image forming apparatus according to claim 6, wherein the link cam body has a locking groove that locks with the spring arm and restricts the movement of the spring arm to one side in the circumferential direction.
The locking groove of the link cam body is cut out in the circumferential direction of the rotational movement of the link cam body. The image forming apparatus according to claim 7, wherein the spring arm abuts against the bottom of the locking groove, thereby restricting the movement of the spring arm in the first direction relative to the link cam body, and the link cam body is allowed to move in the first direction relative to the spring arm by elastic deformation of the spring arm while the shutter remains in the closed position inside the locking groove.
The link cam is movable to a first position in which it moves in the first direction to move the shutter to the closed position, and to a second position in which it moves in the second direction to move the shutter to the open position. The through hole has a first end face located on the first direction side in the circumferential direction and a second end face located on the second direction side in the circumferential direction. The image forming apparatus according to claim 6, wherein the second end face is positioned so as not to contact the boss of the shutter link when the shutter moves from the closed position to the open position while the link cam is in the first position.
The image forming apparatus according to claim 6, wherein the main body-side link moves the shutter link in the second direction in response to the installation of a cartridge attached to the main body of the apparatus, and moves the shutter link in the first direction in response to the detachment of the cartridge from the main body of the apparatus.
The image forming apparatus according to claim 3, wherein, in the sheet transport direction, the connection point between the shutter link and the shutter is located on the opposite side of the connection point between the shutter link and the link cam, with the sheet nip point between the heating member and the pressurizing member in between.
The aforementioned fuser is The fixing frame has a rotating shaft, and the nip pressure changing mechanism changes the nip pressure between the heating member and the pressurizing member by rotating the rotating shaft, The image forming apparatus according to claim 3, wherein the link cam is located coaxially with the rotation axis.
The fixing frame has a second contact surface against which the shutter, in the open position, contacts, When the shutter is in the open position, in contact with the second contact surface, The spring contacts the shutter link and presses the shutter link in the second direction. The image forming apparatus according to claim 3, wherein the movement of the link cam in the second direction is permitted by the elastic deformation of the spring while the shutter remains in the open position.
The image forming apparatus according to claim 13, wherein the second contact surface of the fixing frame faces the upstream side in the sheet transport direction.

Description

This invention relates to an image forming apparatus. Conventionally, in image forming apparatuses equipped with detachable cartridges, a shutter is installed in front of the fuser to prevent the user's hand from coming into contact with the fuser, which has a heating element. For example, the image forming apparatus disclosed in Patent Document 1 includes a link member connected to the shutter and capable of contacting the cartridge. When the cartridge is mounted, the link member contacts the cartridge and moves, and the shutter opens along with the movement of the link member. Furthermore, when the cartridge is removed, the link member moves to the opposite side by spring force, and the shutter closes. Patent No. 6961471 This is a central cross-sectional view showing an image forming apparatus.This is a perspective view showing an image forming apparatus with the front cover in the open position.This is a side cross-sectional view showing the fuser.This is a perspective view showing the heating element and pressure roller of the fuser.(a) is a perspective view showing the fuser with the shutter in the closed position, and (b) is a perspective view showing the fuser with the shutter in the open position.This is a side cross-sectional view showing the fuser.(a) is a side view showing the fuser with the shutter in the closed position, and (b) is a side view showing the fuser with the shutter in the open position.(a) is a front view showing the fuser with the shutter in the closed position, and (b) is a front view showing the fuser with the shutter in the open position.(a) is a front view showing the shutter, and (b) is a side view showing the shutter.This is an exploded perspective view showing the opening and closing links.This is a perspective view showing the open/close link.This is a side cross-sectional view showing the opening and closing link when the shutter is in the closed position.This is a side cross-sectional view showing the opening and closing link when the shutter is in the open position.This is a side view showing the nip pressure changing mechanism.This is a perspective view showing the process cartridge.This is a side view showing the process cartridge.This is a side view showing the left side of the first main frame.This is a side view showing the right side of the first main frame.This is a side view showing the main body side link in a state where the first projection of the contact piece is located in the middle of the contact piece rail and the second projection is located in the front of the contact piece rail.This is a side view showing the first main frame in a state where the process cartridge is in the mounting start position, the first projection of the contact piece is located in the middle of the contact piece rail, and the second projection is located in the front of the contact piece rail.This is a diagram showing the contact piece.This is a side view showing the main body side link in a state where the drum shaft is in contact with the contact piece, and both the first and second projections of the contact piece are located in the middle of the contact piece rail.This is a side view showing the first main frame in a state where the drum shaft is in contact with the contact piece, and both the first and second projections of the contact piece are located in the middle of the contact piece rail.This is a side view showing the main body side link in a state where the drum shaft is in contact with the contact piece, the first projection of the contact piece is located at the rear of the contact piece rail, and the second projection is located in the middle of the contact piece rail.This is a side view showing the first main frame in a state where the drum shaft is in contact with the contact piece, the first projection of the contact piece is located at the rear of the contact piece rail, and the second projection is located in the middle of the contact piece rail.This is a side view showing the first main frame in a state where the drum shaft is separated from the contact piece and the process cartridge is in the mounting position.This is a side cross-sectional view showing the positional relationship between the boss of the shutter link and the second end face of the through hole when the shutter moves from the closed position to the open position with the link cam in the first position. Next, embodiments for carrying out the present invention will be described with reference to the attached drawings. [Image forming apparatus] The image forming apparatus 1 shown in Figure 1 is an embodiment of an image forming apparatus equipped with a sheet transport device according to the present invention, and is a laser printer that forms an image on a sheet S by an electrophotographic method. In the following explanation, the right side of Figure 1 is defined as the front side of the image forming apparatus 1, and the left side of Figure 1 is defined as the rear side of the image formin