JPH10161453A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of obtaining desired strength by loading a reinforcing member, even if a fixing roller is a thin one and further, surely fixing the reinforcing member loaded in the fixing roller. SOLUTION: In the fixing roller 1, at least a hand-drum-like part is formed in a middle area and the outer circumferential edge side of the reinforcing member 11 is bent to provide a cylindrical flat part coming into contact with the inner periphery of the fixing roller 1. Then, the diameter L of the reinforcing member 11 is set within the range from the minimum diameter L1 to the maximum diameter L2 in the hand-drum-like part and the reinforcing member 11 is inserted into the fixing roller 1 and fixed by the inclination of the hand-drum- like part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller having a heat source therein and having a thin metal core, and a pressure roller abutting on the outer peripheral surface of the fixing roller. And a fixing device provided with a reinforcing member for maintaining a cylindrical shape.

[0002]

2. Description of the Related Art A fixing device of the above type is well known, and is attached to an image forming apparatus mainly using plain paper, such as a printer, a copying machine, a facsimile or the like. In recent years, there has been an increase in energy conservation regulations in various countries for OA equipment, and there is a demand to turn off the heater during standby in a fixing device having a large power consumption ratio in order to cope with the movement. In order to satisfy the demand, from the standby OFF, so that the user can start up to the set temperature within a time that does not cause dissatisfaction,
There is a technical tendency to reduce the heat capacity by reducing the thickness of the fixing roller.

[0003] In a fixing device according to this tendency, the mechanical strength of the fixing roller is reduced because a thin core is used for the fixing roller. Therefore, the fixing roller 1 shown in FIG.
In a fixing device having a general configuration including the fixing roller 100 and the pressure roller 101, if the fixing roller 100 is a thin-walled roller, the mechanical strength is weak, so that a bending as shown in FIG. There is a possibility that the portion pressed against the pressure roller 101 may be crushed in the axial direction. When the fixing roller 100 is bent, a gap is formed between the fixing roller 100 and the pressure roller 101 to cause a fixing failure. When the fixing roller 100 is crushed, the fixing roller 100 is damaged.

In order to solve such a problem, there has been proposed a method in which the fixing roller itself has a reinforcing rib shape. In this method, in order to obtain a certain degree of strength for the fixing roller, the ribs must be considerably high, resulting in an increase in processing cost and an economic problem. Further, increasing the height of the rib causes a delay in temperature rise in the portion, which causes a problem that extra waiting time is required until a uniform temperature distribution is obtained.

As another solution, a method has been proposed in which a ring-shaped reinforcing member is loaded into a fixing roller. In this method, the bending and crushing of the fixing roller can be significantly reduced, and the workability is also improved by loading a reinforcing member in advance when grinding and cutting a thin fixing roller having low mechanical strength. The advantage is obtained. Therefore, the method of loading the reinforcing member is more preferable than the method of providing the reinforcing rib shape.

However, since a large load is applied to the reinforcing member for preventing the deformation of the fixing roller, the reinforcing member comes off immediately.
Further, when the fixing roller is pressed by the pressing roller,
It has been confirmed that a thrust force that causes the reinforcing member to slide on the inner surface of the fixing roller is generated, and the reinforcing member is easily detached by this thrust force. May be damaged. Therefore, the reinforcing member must be firmly fixed to the fixing roller. Conventionally, as a method for fixing the reinforcing member, fixing in a shrunk state, fixing by welding, etc., and a member for supporting the reinforcing member It is proposed to provide and fix.

[0007]

However, when the reinforcing member is fixed in a shrunk state, a high precision is required for the size and the like of the reinforcing member, and there is a problem that the loading operation requires a technique.

Further, when the reinforcing member is fixed by welding or the like, there is a problem that not only the processing cost is increased, but also the load is concentrated on the welded portion, and the reinforcing member is broken due to cracks or the like.

Further, when a member for supporting the reinforcing member is provided and fixed, the heat capacity of the fixing roller is increased, and
There is a problem that the effect of thinning the fixing roller is impaired due to a delay in temperature rise.

The present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide a fixing device which can obtain a desired strength by loading a reinforcing member even with a thin fixing roller, and can surely fix the reinforcing member loaded on the fixing roller.

[0011]

In order to achieve this object, the present invention comprises a thin cylindrical fixing roller having a heat source therein, and a pressure roller abutting on the outer peripheral surface of the fixing roller. And a fixing device provided with a ring-shaped reinforcing member for holding a cylindrical shape in the fixing roller,
The fixing roller is provided with a knob-shaped portion at least in an intermediate region, and the reinforcing member is provided with a cylindrical flat portion that is bent at an outer peripheral edge and abuts on an inner peripheral surface of the fixing roller, and has a diameter. It is set within the range from the minimum diameter to the maximum diameter of the knob-shaped part, and the reinforcing member is inserted into the fixing roller and fixed by the inclination of the knob-shaped part.

According to the present invention, when the reinforcing member is inserted into the fixing roller with the side opposite to the side where the cylindrical flat portion is provided as a tip end, and is fixed by the knob-shaped portion,
It is effective.

Further, according to the present invention, the knob portion is provided in the entire length of the fixing roller or in a region from near one end to near the other end, and the reinforcing member is mounted at three places near the center of the fixing roller and near each end. Is effective.

Further, the present invention is effective when the cylindrical flat portion provided on the reinforcing member is inclined at substantially the same angle as the inclination angle of the knob portion.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing an example of the fixing device according to the present invention.

In FIG. 1, the fixing device has a fixing roller 1 and a pressure roller 2 pressed against the fixing roller 1.
Inside, a release layer (not shown) made of a heat-resistant release material such as Teflon (trade name) is provided on the surface, and a heater 3 as a heat source is provided inside. In the case of this example, the core metal of the fixing roller 1 is made of aluminum, iron, or the like that is well-balanced in terms of thermal conductivity, mechanical strength, and cost, and has an outer diameter of about 20 to 40 mm and a thickness of 0. A thin pipe having a thickness of about 3 to 0.8 mm is used. Since the heat capacity of the fixing roller 1 thus configured is extremely small, the rise time of the fixing roller 1 can be reduced and power consumption can be reduced.

In this embodiment, a halogen lamp having excellent heat response and durability is used as the heater 3, and both ends of the heater 3 are held by brackets (not shown). (Not shown). The fixing roller 1 has bearings 20 and 21 at both ends thereof.
The fixing roller 1 is rotatably supported by side plates via bearings 20 and 21. Further, a gear 22 is provided at one end of the fixing roller 1 to receive a drive from a drive source (not shown).

In the fixing roller 1, a reinforcing member 11 for holding the cylindrical shape is provided, and the reinforcing member 11 is provided with a through hole passing through the heater 3 at the center as shown in FIG. The outer peripheral side is bent at a substantially right angle in one direction over the entire circumference to form a cylindrical flat portion 12.

According to the study of the present inventor, when the reinforcing member 11 provided with the cylindrical flat portion 12 is loaded on the fixing roller 1 as described above, the reinforcing member 11 has the cylindrical flat portion 12.
It has been confirmed that a thrust force is generated in a direction opposite to the direction in which the thrust extends, and the thrust moves. The reason is that the extending edge of the cylindrical flat portion 12 becomes a load resistance against the movement, and that the reinforcing member 11 is compressed up and down, so that the cylindrical flat portion 12 falls down and the thrust on the bending side is reduced. It is assumed that

Therefore, in the present invention, as shown in FIG. 3, the fixing roller 1 is formed into a tabular shape with a gradually decreasing diameter at the center with respect to both ends by plastic working. The fixing device of this example is substantially symmetrical about the center, and the center is the minimum diameter, and the diameter gradually increases toward each end, and the bearings 20, 21 and gears 22 are mounted near the end. It is formed almost straight. Accordingly, the inner diameter of the fixing roller 1 is the largest diameter L2 at both ends and the smallest diameter L1 at the center. The reinforcing member 11 has an outer diameter L from the minimum diameter L1 of the fixing roller inner diameter to the maximum diameter L2.
And the reinforcing member 1 as shown in FIG.
When 1 is provided only near the center where the load is concentrated, the diameter L of the reinforcing member 11 is formed to be slightly larger than the minimum diameter L1 of the inner diameter of the fixing roller. The angle of inclination of the fixing roller 1 in the knob shape is arbitrary, and is set to such an extent that the fixing performance is not adversely affected. However, in FIG. 3, in order to clearly show the knob shape, the inclination angle is increased. I have.

The reinforcing member 11 constructed as described above
Is inserted into the fixing roller 1 from the bending side portion of the cylindrical flat portion 12, that is, from the side opposite to the extended side of the cylindrical flat portion 12. At this time, the diameter L of the reinforcing member 11 is slightly larger than the minimum diameter L1 of the inner diameter of the fixing roller. As described above, if the diameter L of the reinforcing member 11 is set so as to stop at the center of the fixing roller 1, the central portion of the fixing roller 1 undergoes a combined deformation of bending and crushing. Accordingly, it is possible to efficiently prevent the fixing roller 1 from being crushed.

In the fixing device constructed as described above, since the thrust force applied to the reinforcing member 11 loaded on the fixing roller 1 is in a direction to bite into the inner wall of the fixing roller 1, the reinforcing member 11 is firmly fixed. Therefore, since the reinforcing member 11 does not need to have high precision unlike the fixing member in the state of shrinking and does not need to be fixed by welding or the like, the processing cost can be greatly reduced.

Further, as shown in FIG.
By inserting the fixing roller 1 from both ends and arranging the fixing roller 1 two at the center and back to back, it is possible to more efficiently prevent the fixing roller 1 from being crushed. Note that the material of the reinforcing member 11 is desirably the same as the core metal material of the fixing roller 1 from the viewpoint of thermal expansion.

FIG. 5 is an explanatory sectional view showing another embodiment of the present invention. In the case where the pressure of the pressing roller 2 for pressing the fixing roller 1 is large, the reinforcing member 11 is used.
Are loaded in three places on the center and both sides. The reinforcing members 11 on both sides are mounted at positions corresponding to the bearings 20 and 21. The bearings 20 and 21 support both ends of the fixing roller 1, and a shearing force acts on that portion, so that an effective reinforcing effect is obtained. can get. Further, as shown in FIG. 6, the reinforcing members 11 on both sides may be loaded at positions corresponding to the ends of the pressure roller 2, and if loaded in this way, the deformation of the fixing roller 1 within the range to be pressed can be achieved. Can be effectively reduced.

As described above, when the reinforcing member 11 is loaded in three places at the center and on both sides, the reinforcing member 11 has a center diameter slightly larger than the minimum diameter L1 of the inner diameter of the fixing roller and a fixing roller for both ends. A roller slightly smaller than the maximum diameter L2 of the roller inner diameter is prepared. Then, the reinforcing members 11 of both types
7, both are inserted from the side opposite to the bending of the cylindrical flat part 12, whereby the reinforcing member 11 is firmly fixed by the thrust force. FIG. 8 shows the reinforcing member 1.
An example is shown in which two central reinforcing members 11 when three are mounted at the center and on both sides are arranged side by side.

FIG. 9 is an explanatory sectional view showing still another embodiment of the present invention, in which the cylindrical flat portion 12 provided on the reinforcing member 11 has substantially the same angle as the inclination angle of the knob portion of the fixing roller 1. Is inclined. The reinforcing member 11 having the inclined cylindrical flat portion 12 is inserted along the inclination of the fixing roller 1 so that the reinforcing member 11 is securely fixed to the fixing roller 1 by the inclined cylindrical flat portion 12. You. FIG. 10 shows an example in which two reinforcing members 11 having the inclined cylindrical flat portions 12 are arranged side by side.

[0027]

According to the first aspect of the present invention, the fixing roller has a knob-shaped portion formed at least in an intermediate region, and the reinforcing member has a cylindrical shape in which the outer peripheral edge is bent and abuts against the inner peripheral surface of the fixing roller. Since the flat portion is provided and its diameter is set within the range from the minimum diameter to the maximum diameter of the knob-shaped portion, the reinforcing member is inserted into the fixing roller and fixed in the knob-shaped portion. Since the reinforcing member does not require high precision and does not need to be fixed by welding or the like, the processing cost can be greatly reduced.

According to the second aspect of the present invention, the reinforcing member is inserted into the fixing roller with the end opposite to the side where the cylindrical flat portion is provided, and is fixed in the knob-shaped portion. Due to the thrust force applied to the member,
Can be fixed firmly.

According to the third aspect of the present invention, the knob portion is provided in the entire length of the fixing roller or in a region from near one end to near the other end, and reinforcing members are loaded at three places near the center of the fixing roller and near each end. Therefore, the pressing force can be increased to satisfactorily reinforce the fixing roller.

According to the fourth aspect of the present invention, the cylindrical flat portion provided on the reinforcing member is inclined at substantially the same angle as the inclination angle of the knob portion, so that the reinforcing member can be more securely attached to the fixing roller. Can be fixed.

[Brief description of the drawings]

FIG. 1 is a vertical center sectional view showing an example of a fixing device according to the present invention.

FIG. 2 shows an example of a reinforcing member, (a) is a sectional view,
(B) is the front view, (c) is a perspective view.

FIG. 3 is an explanatory view showing a fixing roller in which a reinforcing member is loaded in the fixing device of FIG. 1;

FIG. 4 is an explanatory diagram showing a fixing roller loaded with two reinforcing members.

FIG. 5 is a vertical center sectional view showing an example of the arrangement of reinforcing members.

FIG. 6 is a vertical center sectional view showing another arrangement example of a reinforcing member.

FIG. 7 is an explanatory view showing a fixing roller loaded with a reinforcing member in the fixing device of FIGS. 5 and 6;

FIG. 8 is an explanatory diagram showing a fixing roller in which two reinforcing members at the center are loaded.

FIG. 9 is an explanatory view showing a fixing roller loaded with another reinforcing member.

FIG. 9 is an explanatory diagram showing a fixing roller in which two reinforcing members are loaded.

FIG. 11 is an explanatory diagram showing a conventional fixing device.

FIG. 12 is an explanatory diagram illustrating an example of a defect of a conventional fixing device.

FIG. 13 is an explanatory diagram showing another problem of the conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Heater 11 Reinforcing member 12 Cylindrical flat part

Claims (4)

[Claims] 1. A ring for holding a cylindrical shape in the fixing roller, the fixing roller having a thin cylindrical fixing roller having a heat source therein, and a pressing roller abutting on an outer peripheral surface of the fixing roller. In the fixing device provided with a reinforcing member in the shape of a circle, the fixing roller has a tab-like portion formed at least in an intermediate region, and the reinforcing member has a cylindrical shape whose outer peripheral edge side is bent and abuts on the inner peripheral surface of the fixing roller A flat flat portion is provided, and the diameter of the flat portion is set in a range from a minimum diameter to a maximum diameter of the knob-shaped portion. The reinforcing member is inserted into the fixing roller to form the knob-shaped portion. A fixing device characterized by being fixed at an inclination. 2. The fixing device according to claim 1, wherein the reinforcing member is inserted into the fixing roller with a side opposite to a side where the cylindrical flat portion is provided as a tip end, and the reinforcing member is provided at the tab-like portion. A fixing device characterized by being fixed. 3. The fixing device according to claim 1, wherein the knob portion is provided in a region from the entire length of the fixing roller or from near one end to near the other end, and the reinforcing member has a central portion and each end of the fixing roller. The fixing device is mounted in three places near the unit. 4. The fixing device according to claim 1, wherein the cylindrical flat portion provided on the reinforcing member has an inclination substantially equal to the inclination angle of the knob portion. Characteristic fixing device.