JPH0844236A - Fixing device - Google Patents

Abstract

(57) [Abstract] [Object] An object of a first invention of the present application is to provide a fixing device capable of easily removing a core metal of a heating roller without damaging the core metal. A U-shaped fitting opening whose pressure contact side with a pressure roller 13 is open is provided in a frame body 11 of the upper fixing unit 1, and a bearing 5 of a heating roller 3 is fitted into the fitting opening. The hooks 21 of the frame body 11 cause the bearing 5
Supports a part of the outer circumference of. In addition, the fixing upper unit 1
The lower fixing unit 2 on which the pressure roller 13 is supported is supported so as to be openable and closable around the support shaft 9, and one end is supported by the frame body 11 of the upper fixing unit 1, and the other end is supported by the frame body 11. The bearing 5 is held by a bearing retainer 22 which is a rod-shaped elastic member detachably engaged with the convex portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device which is used in an image forming apparatus such as a copying machine or a printer and which has a heating roller and a pressure roller to fix a toner image on a sheet. The present invention relates to a fixing device separately provided in two separable units.

[0002]

2. Description of the Related Art Conventionally, a fixing device for fixing a toner image on a sheet by using a heating roller and a pressure roller, cleans and replaces each roller, and performs maintenance such as processing when the sheet is wound around the roller. Therefore, there is a fixing device in which a heating roller and a pressure roller are separately provided in two separable units, and the two units are separated as needed.

In the above fixing device, the heating roller is rotatably supported via a gear, a bearing and a bush arranged coaxially with the heating roller, and is usually mounted on an upper unit above the fixing device. It is held by fixing the bearing with a fastening member such as a screw. On the other hand, the pressure roller is rotatably supported by a lower unit below the fixing device via a bearing, and urges the bearing by a pressure member that is rotatably arranged as a biasing means. It is pressed against the fixing roller.

Therefore, in this fixing device, the lower unit itself is rotatably supported by the upper unit, and after the pressure member is rotated in the urging release direction,
The pressure roller can be easily replaced by opening the lower unit.

[0005]

However, in the above-mentioned conventional fixing device, when the fixing performance deteriorates due to scratches on the outer peripheral surface of the heating roller or deterioration of durability, the heating roller needs to be replaced. Since the roller is fixed to the upper unit as described above, there is a problem that even if the lower unit is opened as described above, it cannot be easily replaced like the pressure roller.

Further, although the heating roller reuses only the cored bar, in the above-mentioned conventional example, there is a problem that the cored bar is scratched when disassembled because it is difficult to remove the heating roller.

Further, it is considered that the upper unit on the heating roller side can be freely rotated so that the heating roller can be easily removed from the upper unit side, but there is a fear that the heating roller may fall off when the upper unit is rotated.

An object of the first invention of the present application is to solve the above problems and to provide a fixing device which can be easily removed without damaging the core metal of the heating roller.

The second object of the present invention is to:
In addition to the above object, it is an object of the present invention to provide a fixing device capable of preventing the heating roller from falling off and holding the heating roller on the upper unit side.

Further, in addition to the above objects, an object of the third invention of the present application is to provide a fixing device capable of preventing the heating roller from falling off and holding the heating roller on the lower unit side. .

[0011]

According to the first invention of the present application, the above object is to provide a heating roller and a pressure roller which are arranged so as to be in pressure contact with each other by a biasing means, and the heating roller and An upper and lower unit that has a frame body in which a fitting opening portion that can be fitted with the shaft portion of the pressure roller is formed, and an upper unit on the heating roller side and a lower unit on the pressure roller side are arranged to be separable from each other. In the fixing device including a unit, the upper unit on the heating roller side is rotatably supported by the lower unit on the pressure roller side, and the fitting opening of the frame body on the upper unit side. The part is U-shaped with one side of the frame body open, and is provided with a holding means for holding the heating roller in a substantially predetermined position with respect to one of the upper and lower units, which is detachable from the heating roller. It is achieved by

According to the second invention of the present application,
The above object is achieved in the first aspect of the present invention, in which the holding means for holding the heating roller at a substantially predetermined position is a member provided in the upper unit on the heating roller side.

Further, according to the third invention of the present application, in the above-mentioned first object, the holding means for holding the heating roller at a substantially predetermined position is provided in the lower unit on the pressure roller side. It is achieved by being a member.

[0014]

According to the first aspect of the present invention, when the heating roller is held at the substantially predetermined position on the upper unit side by the holding means, the upper unit on the heating roller side is rotated to the open position. However, since the heating roller is separated from the pressure contact position with the pressure roller together with the upper unit without dropping off, the work area for disassembling the heating roller is expanded and the core metal of the heating roller is not damaged. Also, when in the open position,
By removing the holding means, the heating roller can be easily removed from the opening of the U-shaped fitting opening formed on the frame. Further, at the time of assembly, the heating roller is fitted into the fitting opening from the opening, and after the holding means is attached, the upper unit is rotated to the closed position to obtain the pressure contact state with the pressure roller. To be

When the heating roller is held at a substantially predetermined position on the lower unit side by the holding means, when the upper unit is rotated to the open position, a U-shaped fitting opening is formed in the frame of the upper unit. Since the portion is formed, only the upper unit rotates, and the heating roller maintains the pressure contact state with the pressure roller. Therefore, the member covering the periphery of the heating roller is removed and the working area is expanded, so that the disassembling work can be performed without damaging the core metal of the heating roller. Also, the heating roller can be easily removed from the holding means. On the other hand, at the time of assembly, the heating roller is held by the holding means and the upper unit is rotated to the closed position, so that the heating roller is fitted into the fitting opening from the opening.

According to the second invention of the present application,
In the first aspect of the invention, since the holding means is provided in the upper unit on the heating roller side, the upper unit is opened and closed even if the fitting opening of the upper unit is U-shaped with one side of the frame body open. Prevents the heating unit from falling off from the opening of the fitting opening when moved.

Further, according to the third invention of the present application, in the above first invention, since the holding means is provided in the lower unit on the pressure roller side, the shape of the fitting opening of the upper unit is framed. Even if the body has a U-shape with one side open, the heating roller is held on the lower unit side regardless of the opening / closing movement of the upper unit.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional configuration diagram of a fixing device embodying the present invention. In FIG. 1, reference numeral 1 denotes an upper fixing unit, and the upper fixing unit 1
A hollow cylindrical heating roller 3 whose both ends are rotatably supported by bearings 5 is detachably attached to the roller. Inside the heating roller 3,
The heater 4 is provided, and the heating roller 3 is further provided.
A cleaning web 6 for cleaning the outer peripheral surface is pressed against the outer peripheral surface by a web roller 7. Reference numeral 8 is a cover for covering the upper fixing unit 1, and 11 is a frame body of the upper fixing unit 1.

Reference numeral 2 denotes a lower fixing unit, and the lower fixing unit 2 includes a sheet entrance guide 12 and a pressure roller 13 rotatably supported by bearings 14 at both ends.
A pressure member 15 as a biasing means is attached. The pressure member 15 is swingable around a support shaft 17, and the pressure spring 16 urges the bearing 14 to press the pressure roller 13 against the heating roller 3. Reference numeral 19 denotes a frame body of the lower fixing unit 2.

The upper fixing unit 1 is supported so as to be openable and closable with respect to the lower fixing unit 2 about a support shaft 9,
When it is in the closed state, it is fixed to the lower fixing unit 2 by fixing a mounting portion 10 arranged at a position facing the support shaft 9 with a screw.

Next, the supporting portion of the heating roller 3 in this embodiment will be described in detail with reference to FIG. FIG. 2 is a perspective view showing a support portion of the heating roller 3 of the upper fixing unit 1, and as shown in FIG. 2, the frame 11 of the upper fixing unit 1 has a shaft of a bearing 5 attached to the heating roller 3. A plurality of hook portions 21 that support the direction are provided, and the hook portions 21 support a part of the outer periphery of the bearing 5.
Further, the shape of the fitting opening formed on the frame body 11 with the bearing 5 is not circular, and the pressure contact side with the pressure roller 13 is opened so that the heating roller 3 can be easily attached and detached. It has a U shape.

Therefore, when the upper fixing unit 1 is rotated in the opening direction, the heating roller 3 may unintentionally drop off from the open side of the fitting opening, and therefore, in this embodiment. Then, the bearing 5 is held by the bearing retainer 22 as a holding means. Bearing retainer 2
2, one end is supported by the frame body 11 of the upper fixing unit 1,
As shown in FIG. 2, the other end is a rod-shaped elastic member that is detachably engaged with the convex portion of the frame body 11, and prevents the bearing 5 from falling off at the position shown in FIG.

Next, the removal of the heating roller 3 will be described. The upper fixing unit 1 including the heating roller 3 includes the fixing unit 1 for fixing the upper and lower fixing units 1 and 2 as described above.
As shown in FIG. 4, it is possible to rotate the support shaft 9 in the opening direction by using the support shaft 9 as a fulcrum by releasing the fixation of the 0 screw or the like. In this way, when the fixing upper unit 1 is opened,
The pressure member 15 that has been urging the pressure roller 13 tries to swing further in the pressure direction, but as shown in FIG. 1, it contacts a stopper 18 provided above the pressure member 15, Further swinging is stopped.

When the fixing upper unit 1 is rotated to a position in which the opening side of the fitting opening of the frame 11 faces upward as shown in FIG. 4, the work area is expanded and the heater 4 can be easily heated. It can be removed. Further, the heating roller 3 from which the heater 4 is removed can be easily removed from the open side of the fitting opening of the frame body 11 when the engagement of the bearing retainer 22 with the frame body 11 is released as described above. I can. At this time, the bearing 5, the gear 20 and the like are attached to the heating roller 3, but the work area is expanded by rotating the fixing upper unit 1 to such a position,
The bearing 5, the gear 20 and the like can be removed from the heating roller 3 in this state and disassembled without damaging the cored bar portion.

On the other hand, when attaching the heating roller 3,
The heating roller 3 to which the bearing 5, the gear 20 and the like are attached is installed in the hook portion 21
And hold it by the bearing retainer 22. Next, the upper fixing unit 1 is rotated to the closed position, and the fixing upper and lower units 1 and 2 are fixed by the fixing portion 10.

The bearing retainer 22 used in this manner does not necessarily need to hold the heating roller 3 at a predetermined position during installation, disassembly, and operation, and it is sufficient if the heating roller 3 can be held at a substantially predetermined position. Is.
That is, the bearing 5 is positioned by the frame body 11,
The bearing retainer 22 merely serves to prevent the bearing 5 of the heating roller 3 from falling off.

As described above, according to the present invention, the heating roller can be easily removed without damaging the core metal of the heating roller.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 5 shows a means for holding the heating roller 3,
FIG. 6 is a cross-sectional view showing a fixing device including a bearing holding member 25 provided in the lower fixing unit 2. In FIG. 5, the bearing holding member 25 is formed of sheet metal or the like, and is fixed to the frame body 19 of the lower fixing unit 2 at a position facing the bearing 5 of the heating roller 3.

The bearing holding member 25 supports only the lower side of the bearing 5, as shown in FIG.
Similar to the above embodiment, it is supported by the hook portion 21 provided on the frame body 11 of the upper fixing unit 1.

Even when the fixing upper unit 1 is rotated to the open position as shown in FIG. 6 when the heating roller 3 is disassembled, the bearing holding member 25 causes the heating roller 3 to be substantially fixed on the pressure roller 13. Hold it in position.

Therefore, also in the present invention, the work area is widened, and the heating roller can be easily disassembled without damaging the core of the heating roller.

[0034]

As described above, the first aspect of the present application
According to the invention, the upper unit on the heating roller side is rotatably supported by the lower unit on the pressure roller side, and the fitting opening portion of the frame body on the upper unit side is opened on one side of the frame body. Since the holding means for holding the heating roller in a substantially predetermined position with respect to one of the upper and lower units is detachably attached to the heating roller, the heating roller can be easily disassembled and assembled. Therefore, the heating roller can be easily replaced. Furthermore, it has become possible to replace the core of the heating roller without damaging it.

According to the second invention of the present application,
In the first aspect of the invention, since the heating roller holding means is provided in the upper unit, the bearing of the heating roller is replaced when the heating roller is replaced and reassembled while preventing the heating roller from falling off when the heating roller is disassembled. It can be easily adjusted to the predetermined position of the upper unit.

Further, according to the third invention of the present application, in the first invention, the holding means for the heating roller is provided in the lower unit, so that the heating roller is prevented from falling off when the heating roller is disassembled. When the heating roller is replaced and reassembled, the heating roller can be arranged at a substantially predetermined position on the pressure roller, and the heating roller can be easily handled.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a fixing device according to a first exemplary embodiment of the present invention.

FIG. 2 is a perspective view showing a heating roller support portion in the apparatus shown in FIG.

FIG. 3 is a cross-sectional view showing an arrangement position of a heating roller holding unit in the apparatus shown in FIG.

FIG. 4 is a diagram showing a state in which an upper unit in the apparatus shown in FIG. 1 is moved to an open position.

FIG. 5 is a sectional view showing an arrangement position of holding means in a second embodiment of the present invention.

6 is a diagram showing a state in which an upper unit is moved to an open position in the fixing device having the holding unit of FIG.

[Explanation of symbols]

 1 Upper Fixing Unit (Upper Unit) 2 Lower Fixing Unit (Lower Unit) 3 Heating Roller 11 Frame 13 Pressure Roller 15 Pressurizing Member (Biasing Means) 22 Bearing Presser (Holding Member) 25 Bearing Holding Member (Holding Member)

Claims (3)

[Claims] 1. A frame formed with a heating roller and a pressure roller which are arranged so as to come into pressure contact with each other by an urging means, and a fitting opening which can be fitted to the shaft portion of the heating roller and the pressure roller. In a fixing device having a body, an upper unit on the heating roller side and a lower unit on the pressure roller side and an upper and lower unit which are arranged so as to be separable from each other, the upper unit on the heating roller side is The heating roller is rotatably supported by the lower unit on the pressure roller side, and the fitting opening of the frame on the upper unit side is U-shaped with one side of the frame open. 2. A fixing device, characterized in that a holding means for holding at least one of the above and below units is detachably attached to the heating roller. 2. The fixing device according to claim 1, wherein the holding means for holding the heating roller at a substantially predetermined position is a member provided in an upper unit on the heating roller side. 3. The fixing device according to claim 1, wherein the holding unit that holds the heating roller at a substantially predetermined position is a member provided in the lower unit on the pressure roller side.