JP3378408B2 - Fixing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device applied to a copying machine, a printer and a facsimile.

[0002]

2. Description of the Related Art Conventionally, this type of technology has
There is one disclosed in Japanese Patent No. 3323. According to this, the heating roller and the drive gear are coaxially arranged with a small-diameter portion provided on the shaft of the drive gear positioned in the hollow portion of the core of the heating roller, and a gap is formed between the fitting portions of both members. The fixing device is described in which a spring member is formed over both members, and the inner diameter of the spring member is smaller than the outer diameter of the two members of the heating roller and the shaft of the gear. ing.

FIG. 15 is a block diagram showing the essential parts of a conventional fixing device. 1 is a base roller, 2 is a heating layer, 3 is an insulating protective layer, 4 is a heating roller, 5 is a spring, and 6 is drive transmission. The means is shown.

The base roller 1 is a cylindrical member made of a material such as ceramics. The heating roller 4 is constructed by providing a heating layer 2 on the surface of the base roller 1 and further providing an insulating protective layer 3 thereon. To be done. The heating roller 4 and the drive transmission means 6 configured as described above are fitted coaxially with each other while forming a gap, and a spring 5 having an inner diameter smaller than the outer diameter of the heating roller 4 is wound around the outer circumferences of both members. Heating roller 4 without notching base roller 1
And the drive transmission means 6 are connected.

With this structure, when the drive transmission means 6 rotates in the tightening direction of the spring 5, the rotational force can be transmitted to the heating roller 4.

[0006]

However, when a jam occurs in the fixing portion of the electrophotographic apparatus, when the user pulls out the jammed paper in the paper discharge direction, the heating roller 4 rotates and the spring 5 exerts a force in the loosening direction. Therefore, slippage may occur between the heating roller 4 and the spring 5, or between the drive transmission means 6 and the spring 5, and the base roller 1 may be damaged. Particularly, if the base roller 1 is damaged, the base roller 1 is likely to be damaged, and if the heat generating layer 2 is present between the base roller 1 and the spring 5, if the heat generating layer 2 is damaged, an electric heat generation failure occurs.
Therefore, there is a problem that fixing failure may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a fixing device capable of preventing the heating roller from being damaged when the jammed paper is removed when a jam occurs in the heating roller. .

[0008]

In order to solve the above problems, the present invention provides a cylindrical and insulating base roller, a heating element layer formed on an outer peripheral surface or an inner peripheral surface of the base roller, and A heating roller having an insulating protective layer formed on the heating element layer on the outer peripheral surface of the base roller or on the outer peripheral surface of the base roller, and fitted to the heating roller and arranged coaxially with the heating roller. In a fixing device having a drive transmission means for transmitting drive from the drive roller to the heating roller to drive and rotate it, and a heating roller and a spring wound around the outer periphery of the drive transmission means, the fixing roller is in contact with the heating roller in the spring. The number of windings of the portion that is in contact with the drive transmission means is set to be larger than that of the portion that is in contact with the drive transmission means, When the relatively rotating in the loosening direction, characterized in that slippage between the drive transmitting means and the spring was made to occur.

Further, in the shape of the spring before assembly, the inner diameter of the portion contacting the heating roller is smaller than the inner diameter of the portion contacting the drive transmission means.

Further, the outer diameter of the portion of the heating roller which comes into contact with the spring is larger than the outer diameter of the portion of the drive transmission means which comes into contact with the spring.

Further, according to the present invention, a cylindrical and insulating base roller, a heating element layer formed on an outer peripheral surface or an inner peripheral surface of the base roller, and a heating element layer on the outer peripheral surface of the base roller or the base. A heating roller having an insulating protection layer formed on the outer peripheral surface of the roller, and a heating roller fitted to the heating roller and arranged coaxially with the heating roller, transmitting drive from a drive source to the heating roller and rotating the drive. In a fixing device having a drive transmission means for causing the heating roller and a spring wound around an outer circumference of the heating roller, when the spring is attached to the heating roller, the drive transmission means is in one direction relative to the heating roller. The drive transmission means is further provided with an abutting portion with which either end portion of one end of the spring comes into contact with the drive transmission means when rotated in either direction. Both ends of the spring are in the vicinity of the abutting portion so that the abutting portion causes the spring to rotate in the tightening direction when the drive transmission means is rotated in one direction relative to the heating roller. And an engaging portion that restricts the movement of the both end portions is provided at or near a portion that abuts both end portions of the spring.

Further, a recess is provided around a fitting portion of the drive transmission means with the heating roller, and at least a part of the abutting portion and the spring are inserted into the recess. To do.

Further, an inner peripheral portion of the heating roller is fitted to an outer peripheral portion of a convex portion formed in the concave portion of the drive transmission means.

[0014]

According to the above construction, since the number of turns of the spring is greater than the number of turns of the spring in contact with the heating roller and the number of turns of contact with the drive transmission means, a force is applied in the loosening direction of the spring. At this time, slippage occurs between the drive transmission means having a small number of turns and the spring, and slippage does not occur easily between the heating roller and the spring.

Further, since the tightening force of the spring to the heating roller becomes stronger than the tightening force to the drive transmission means due to the difference in inner diameter of the spring, when a force is applied in the loosening direction of the spring, the tightening force is weak. Slip occurs between the drive transmission means and the spring.

Further, since the outer diameter of the portion of the heating roller in contact with the spring is larger than the outer diameter of the portion of the drive transmission means in contact with the spring, the tightening force of the spring on the heating roller is greater than the fastening force on the drive transmission means. Becomes stronger, and when a force is applied in the loosening direction of the spring, slippage occurs between the drive transmission means having a weak tightening force and the spring.

Further, no matter which direction the drive transmission means is turned, the abutment portion of the drive transmission means abuts either one of both ends of the spring in the direction in which the spring is tightened.
No slippage occurs between the spring and the heating roller. Further, since the abutting portion provided on the drive transmission means is provided with the engaging portion, both ends of the spring are caught by the engaging portion and cannot be disengaged.

Further, the length of the heating roller in the longitudinal direction can be shortened by inserting the abutting portion and the spring into the recess provided in the drive transmission means, so that the apparatus can be miniaturized.

By fitting the inner peripheral portion of the heating roller to the outer peripheral portion of the convex portion formed in the concave portion of the drive transmitting means, the abutting portion and the spring are provided in the concave portion provided on the side surface of the drive transmitting means. Since it can be inserted deeper, the length of the heating roller in the longitudinal direction can be further shortened.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings. The same members as those in the conventional configuration shown in FIG. 15 are designated by the same reference numerals, and detailed description thereof is omitted.

FIG. 1 is an internal configuration diagram showing a main part of a first embodiment of the present invention. The difference between the first embodiment and the conventional configuration shown in FIG. 15 is that the number of windings of the spring 5 is larger than the number of windings of the drive transmission means 6 on the outer periphery of the heating roller 4. is there. At this time, it is desirable that the difference in the number of turns between the two is 2 or more.

With this configuration, when a rotational force is applied to the heating roller 4 in a direction in which the spring 5 loosens, such as when a jam occurs in the fixing device and the jammed paper is removed, the spring is applied. Slip is more likely to occur between the spring 5 and the drive transmission means 6 than between the spring 5 and the heating roller 4, and slippage is less likely to occur between the spring 5 and the heating roller 4. Therefore, the heating element layer 2 and the electrode layer can be made less likely to be damaged.

As shown in FIG. 2, the base roller 1
The heating element layer 2 is formed on the outer peripheral surface of the base roller 1, and the electrode layer 7 electrically connected to the heating element layer 2 is formed at the end of the outer peripheral surface of the base roller 1.
Further, the heating roller comprises a heating element layer 2 and a part of the electrode layer 7 connected to the heating element layer 2, which is covered with an insulating protective layer 3, and even if the electrode layer 7 is wound with a spring 5. The same effect as the first embodiment can be obtained.

Further, as shown in FIG. 13, the base roller 1
Even if the spring 5 is wound directly on the outer circumference of
Further, as shown in FIG. 14, a heating element layer and an electrode layer 7 connected to the heating element layer are formed on the inner peripheral surface of the base roller 1, and the electrode layer 7 is formed so as to wrap around the outer peripheral surface of the base roller 1. Even if it is the heating roller 4 and the spring 5 is wound around the electrode layer 7, the same effect as that of the first embodiment can be obtained.

FIG. 3 is a side sectional view showing the structure of a spring according to the second embodiment of the present invention, and 8 shows the spring. In the third embodiment, a spring 8 shown in FIG. 3 is provided instead of the spring 5 in the first embodiment shown in FIG.

This spring 8 is, as shown in FIG.
By making the inner diameter of the portion around which the heating roller 4 is wound smaller than the inner diameter of the portion around which the drive transmission means 6 is wound, the tightening force is made different.

That is, the tightening force of the portion of the spring 8 around which the heating roller 4 is wound is stronger than the tightening force of the portion around which the drive transmission means 6 is wound, and when a force is applied in the direction in which the spring 8 loosens. The slip is less likely to occur between the spring 8 and the drive transmission means 6 than between the spring 8 and the heating roller. Therefore, it is possible to prevent the heating roller 4, particularly the base roller 1, the heating element layer 2 and the electrode layer 7 of FIGS. In particular, this means is effective when the total number of turns of the spring must be reduced. The difference between the two inner diameters is the average
If it is 0.02 mm or more, an effective tightening force can be obtained, but it is particularly preferable that it is 0.04 mm or more.

FIG. 4 is an internal block diagram showing the essential parts of a third embodiment of the present invention, in which 9 is a heating roller and 10 is a drive transmission means. The same members as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 4, in the third embodiment, the outer diameter of the portion of the heating roller 9 around which the spring 5 is wound is
The outer diameter of the portion of the drive transmission means 10 around which the spring 5 is wound is made larger. As a result, even when a spring having a substantially uniform inner diameter is wound, the tightening force of the portion of the spring around the heating roller 9 can be made stronger than the tightening force of the portion around the drive transmission means 10. It should be noted that an effective tightening force can be obtained if the difference between the two outer diameters is 0.02 mm or more on average, but it is particularly preferably 0.04 mm or more.

Therefore, when a force is applied in the direction in which the spring 5 loosens, slippage is more likely to occur between the spring 5 and the drive transmission means 10 than between the spring 5 and the heating roller 9, and the spring 5 and the heating roller 9 are heated. Sliding with the roller 9 is less likely to occur. Therefore, it is possible to prevent the heating roller 9, particularly the base roller, the heating element layer, and the electrode layer forming the heating roller 9, from being damaged. Further, since it is not necessary to process the spring as in the second embodiment, the above-mentioned effect can be obtained more easily.

By the way, although the heating roller can be prevented from being damaged in the above-mentioned first to third embodiments,
Even slippage between the drive transmission means and the spring is not prevented. With respect to damage to the drive transmission means due to such slippage, although the drive transmission means itself has good slidability, it will not be damaged as much as the heating roller, but there is some concern about its durability. Therefore, the fourth embodiment will consider this point.

FIG. 5 is a side view showing an essential part of a reference example for explaining the fourth embodiment of the present invention, FIG. 6 is a sectional view taken along the line AA of FIG. 5, and FIG. 7 is a sectional view of FIG. And 11 is a heating roller,
Reference numeral 12 is a drive transmission means, 13 is a spring, and 14 is an abutting portion. The drive transmission means 12 is a gear body, and a recess 12a corresponding to the size of the heating roller 11 is formed on the plane thereof, and the axis of this recess 12a coincides with the axis of the heating roller 11. Further, the abutting portion 14 which is a cylindrical protrusion is erected on the same plane. Also, the spring 13
Is a structure in which bent portions 13a and 13b are formed at both ends of the spring 8 according to the second embodiment shown in FIG.

Then, the heating roller 11 is fitted into the recess 12a of the drive transmission means 12, and further the spring 13 is wound around the outer periphery of the heating roller 11, and both ends thereof are bent.
Bent portions 13a and 13b are formed. At that time, as shown in FIG. 6, the bent portions 13a and 13b are located beyond the abutting portion 14, respectively.

With this configuration, the drive transmission means 12 can rotate with respect to the heating roller 11 until the abutting portion 14 abuts the bent portions 13a and 13b at both ends of the spring 13. As a result, as shown in FIG.
Even when 12 rotates and the abutting portion 14 comes into contact with the bent portion 13a, only the heating roller 11 rotates and the abutting portion 14 comes into contact with the bent portion 13b as shown in FIG. However, the abutting part 14 is not
When it abuts on either a or 13b, the rotational force in the abutting direction is transmitted to the heating roller 11. That is, slippage does not occur between the heating roller 11 and the spring 13, and it is possible to prevent the heating roller 11, especially the base roller, the heating element layer, and the electrode layer that form the heating roller 11 from being damaged.

FIG. 10 is a side view showing the construction of the main part of the fourth embodiment of the present invention, wherein 15 is an abutting portion, 16 is a convex portion, and 17 is a concave portion. The fourth embodiment is different in the configuration of the abutting portion 14 in the reference example, the abutting portion 15 is provided with a convex portion 16 in the portion of the abutting portion 14 in the reference example, the bending portion 13a abuts, The concave portion 17 is provided at the portion where the bent portion 13b abuts.

With this structure, when the bent portions 13a and 13b of the spring 13 are in contact with the abutting portion 15, the movement of the heating roller 11 in the longitudinal direction is restricted. As a result, the bent portions 13a and 13b of the spring 13 are abutted with each other.
To prevent slipping between the heating roller 11 and the spring 13 as in the above-mentioned reference example due to the fact that the abutting portion 15 hits the bent portions 13a and 13b of the spring 13 You can

FIG. 11 is a side view showing the structure of the main part of the fifth embodiment of the present invention, FIG. 12 is a sectional view of FIG.
It is sectional drawing which shows the principal part of 6th Example of this invention. Reference numeral 18 is a drive transmission means, 19 is a concave portion composed of a first concave portion 19a and a second concave portion 19b, 20 is a fitting portion, and 21 is an abutting portion.

The drive transmission means 18 is a gear body, and a cylindrical first concave portion 19a is formed in the center of one plane of the drive transmission means 18, and a cylindrical first concave portion 19a is formed around the first concave portion 19a. Two recesses 19b are formed. Then, the first recess 19a
The cylindrical convex portion between the second concave portion 19b and the second concave portion 19b is the fitting portion 20.
The outer diameter of the fitting portion 20 substantially matches the inner diameter of the heating roller 11. Furthermore, the inner diameter of the second recessed portion 19b is substantially equal to the outer diameter of the heating roller 11, and the inner diameter of the opening side is larger than the inner diameter of the inner portion, that is, the second recessed portion 19b is configured as a two-step recessed portion. An abutting portion 21 is provided on the plane of the step portion inside the second recess 19b. The shape of the abutting portion 21 matches the shape of the abutting portion 15 according to the fourth embodiment shown in FIG.

Then, the heating roller 11 is attached to the fitting portion 20, and the tip of the heating roller 11 is fitted into the inner portion of the second recess 19b. Further, the spring 13 is attached to the heating roller 11 as in the fourth embodiment. At this time, the bent portion 13b of the spring 13 is arranged in the second recess 19b.

With this structure, the abutting portion 21 and the spring 13 can be arranged at the back of the second recessed portion 19b formed on the side surface of the drive transmission means, and the longitudinal direction of the heating roller 11 can be improved. Further space saving can be achieved.

[0041]

According to the present invention configured as described above, slippage is more likely to occur between the spring and the drive transmission means than between the spring and the heating roller, so that the heating roller is On the other hand, when a rotational force is applied in the direction in which the spring loosens, the spring and the heating roller will rotate together, which in turn prevents the spring from damaging the heating roller and also causes a failure in energization. It is possible to prevent the occurrence of defective fixing due to defective heat generation.

[Brief description of drawings]

FIG. 1 is an internal configuration diagram showing a main part of a first embodiment of the present invention.

FIG. 2 is an internal configuration diagram showing a main part of another configuration of the first embodiment of the present invention.

FIG. 3 is a side sectional view showing a structure of a spring according to a second embodiment of the present invention.

FIG. 4 is an internal configuration diagram showing a main part of a third embodiment of the present invention.

FIG. 5 is a side view showing a main part of a reference example for explaining a fourth embodiment of the present invention.

6 is a cross-sectional view taken along the line AA of FIG.

7 is a cross-sectional view of FIG.

8 is a cross-sectional view taken along the line AA of FIG. 5 showing the operation of the reference example.

9 is a cross-sectional view taken along the line AA of FIG. 5 showing the operation of the reference example.

FIG. 10 is a side view showing a main configuration of a fourth embodiment of the present invention.

FIG. 11 is a side view showing a main configuration of a fifth embodiment of the present invention.

FIG. 12 is a sectional view showing an essential part of a sixth embodiment of the present invention.

FIG. 13 is an internal configuration diagram showing a main part of another configuration of the first embodiment of the present invention.

FIG. 14 is an internal configuration diagram showing a main part of another configuration of the first embodiment of the present invention.

FIG. 15 is a configuration diagram showing a main part of a conventional fixing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base roller, 2 ... Heating element layer, 3 ... Insulation protective layer, 4, 9, 11 ... Heating roller, 5, 8, 13 ... Spring, 6, 10, 12, 18 ... Drive transmission means, 7 ... Electrode layer , 12a, 19 ... Recessed parts, 13a, 13b ... Bent parts, 14, 1
5, 21 ... Abutting portion, 16 ... Convex portion, 17 ... Concave portion, 19a ... First concave portion, 19b ... Second concave portion, 20 ... Fitting portion.

Claims (6)

(57) [Claims] 1. A cylindrical and insulating base roller, a heating element layer formed on an outer peripheral surface or an inner peripheral surface of the base roller, and a heating element layer on the outer peripheral surface of the base roller or on the outer peripheral surface of the base roller. A heating roller having a formed insulating protection layer, and a drive transmission unit that is fitted to the heating roller and is arranged coaxially with the heating roller, and transmits a drive from a drive source to the heating roller to drive and rotate the heating roller. In the fixing device having the heating roller and a spring wound around the outer circumference of the drive transmission means, the number of windings of a portion of the spring in contact with the heating roller is set to When the heating roller is rotated relative to the drive transmission means in the loosening direction of the spring, the number of turns is set to be larger than the number of windings of the drive transmission means. A fixing device characterized in that a slip is generated between the fixing device and the pulling device. 2. The fixing member according to claim 1, wherein in the shape of the spring before assembly, an inner diameter of a portion contacting the heating roller is smaller than an inner diameter of a portion contacting the drive transmission means. apparatus. 3. The fixing device according to claim 1, wherein an outer diameter of a portion of the heating roller that contacts the spring is larger than an outer diameter of a portion of the drive transmission unit that contacts the spring. . 4. A cylindrical and insulating base roller, a heating element layer formed on the outer peripheral surface or the inner peripheral surface of the base roller, and on the heating element layer on the outer peripheral surface of the base roller or on the outer peripheral surface of the base roller. A heating roller having a formed insulating protection layer, and a drive transmission unit that is fitted to the heating roller and is arranged coaxially with the heating roller, and transmits a drive from a drive source to the heating roller to drive and rotate the heating roller. When, in the fixing device having a spring the wound on the outer circumference of the heating roller, whereby upon mounting the pre-Symbol spring to the heating roller, rotates the drive transmitting means relative direction with respect to said heating roller The drive transmission means, the drive transmission means is provided with an abutting portion with which one of the two ends of the spring comes into contact with the drive transmission means. Both ends of the spring are arranged in the vicinity of the abutting portion so that the abutment portion rotates the spring in the tightening direction when the step is rotated in one direction relative to the heating roller. ,Previous
Note: The part that abuts both ends of the spring or its vicinity
A fixing device characterized in that an engaging portion for restricting movement of the both end portions is provided in the fixing device. 5. The heating wire in the drive transmission means .
A recess is provided around the mating part with the
The pad and at least a part of the spring enter
The fixing device according to claim 4, wherein the fixing device is formed so as to be attached . 6. The drive transmission means is formed in the recess.
Fit the inner circumference of the heating roller to the outer circumference of the raised
The fixing device according to claim 5, wherein the allowed.