JP2000106263A - Heater and heat roller for fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent peeling off and disposition of a jointed part by using a filler having a volume specific resistance of a specified value or more, the specified range of volume and the balance of an insulating heat resistant adhesive, as a matrix, having a specific resistance of a specified value or more, made of organic resin having a specified value or higher temperature causing a decrease in weight of a specified value, elastic modulus of a specified value or less, and elongation of a specified value or more. SOLUTION: Volume specific resistance of a filler is set at 1010 Ωcm or more, the volume is set at 5-85%, the temperature of decrease in 5% weight of organic resin is set at 180 deg.C or higher, the elastic modulus is set at 2,000 kgf/mm2 or less, the elongation is set at 10% or more, and the specific resistance of an insulating heat resistant adhesive is set at 1010 Ωcm or more. A heat roller for fixing has an insulating layer 2 on the inner circumferential surface of a cylinder 1 made of a metal pipe, a heating resistor 3 is installed on the insulating layer 2, an electrode member 5 is fixed to the end of the heating resistor 3 with a conductive paste 4, and a lubricating layer 6 is formed on the outer circumferential surface of the cylinder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater in which a heating resistor is provided on the surface or inside of a base, and an electrode member is joined to an end of the heating resistor, and in particular, an electrophotographic device such as a printer. The present invention relates to a heat roller for fixing toner in an apparatus.

[0002]

2. Description of the Related Art Conventionally, a toner fixing device in an electrophotographic apparatus such as a printer has a heat roller provided with a heat generating means and a pressure roller arranged opposite to each other, and a printed paper passes between these rollers. By doing so, the toner is heated and fixed.

[0003] As the above-mentioned heat roller, a roller in which a heating element such as a halogen lamp is provided in a metal pipe such as aluminum or stainless steel has been used. However, since the heat generation efficiency is low, a warm-up time of one minute or more is required. However, there is a problem that power consumption is large.

Therefore, a heat roller having a structure in which a heating resistor is provided on the surface of a cylindrical body made of a metal pipe via an insulating layer made of an organic resin such as polyimide, and a release layer is further provided on the surface thereof has been proposed. (Japanese Patent Laid-Open No. 55-72390)
And JP-A-62-200380).

[0005] For example, the fixing heat roller shown in FIG. 3 includes an insulating layer 2 on the inner peripheral surface of a cylindrical body 1 made of a metal pipe, and a heating resistor 3 is formed on the insulating layer 2. An electrode member 5 is formed by using a conductive paste 4
And a release layer 6 is provided on the outer peripheral surface of the cylindrical body 1. Although only one end is shown in FIG. 3B, the electrode members 5 are similarly fixed to both ends.

The electrode member 5 has a lid shape that closes the hollow hole of the cylindrical body 1, has a protruding portion formed at the center, and has an end surface serving as a sliding surface 5 a with the power supply member 7. And
When this fixing heat roller is used, the power supply member 7 is brought into contact with the sliding surface 5a of the electrode member 5 provided at the end while rotating the cylindrical body 1, and power is supplied while sliding. The heating resistor 3 can be energized to generate heat.

[0007]

However, in the above-mentioned fixing heat roller, if the electrode member 5 falls off and the circuit of the product is short-circuited, the electrophotographic apparatus itself of the main body burns and a fire is caused. There was a fear that it might cause it.

In a general heater having a structure in which a heating resistor is provided on the surface or inside of a substrate and an electrode member is attached to at least one end of the heating resistor, the electrode member is formed by using a simple conductive paste. If only bonding is performed, if heat or a large force is applied during use, there is a possibility that a problem may occur in that the bonded portion is peeled off and misalignment is likely to occur.

Therefore, it has been necessary to join the electrode member to the heating resistor using a conductive paste and to fix and reinforce the electrode member with an insulating heat-resistant adhesive.

[0010]

Therefore, according to a first aspect of the present invention, there is provided a heater comprising a heating resistor provided on the surface or inside of a base, and an electrode member joined to an end of the heating resistor.
5 to 85% by volume of a filler having a volume resistivity of 10 ¹⁰ Ωcm or more, with the remainder being a matrix having a 5% weight loss temperature of 1%
The specific resistance of an organic resin having an elastic modulus of at least 80 kg, an elastic modulus of 2000 kgf / mm ² or less and an elongation of 10% or more is 10 ¹⁰ Ωcm
Using the above insulating heat-resistant adhesive, fix the electrode member.
It is characterized by reinforcement.

That is, by using a heat-resistant organic resin having a 5% weight loss temperature of 180 ° C. or more as a matrix, a strong adhesive force can be maintained when used at a high temperature. In addition, by using an organic resin having an elastic modulus of 2000 kgf / mm ² or less and an elongation of 10% or more, stress can be absorbed when two or more members having different thermal expansions are joined and fixed. Cracks can be prevented from occurring in the insulating heat-resistant adhesive.

The organic resin used as the matrix is desirably an organic resin having an imide bond such as polyimide or polyamide imide. This is because, by using an organic resin having an imide bond such as polyimide or polyamide imide having excellent heat resistance among organic resins, an insulating heat-resistant adhesive having excellent durability at high temperatures can be obtained. is there. Further, the organic resin used as the matrix has thermoplasticity and a glass transition temperature of 1
When the temperature is 60 ° C. or higher, the stress generated from the difference in thermal expansion between the adherends can be absorbed and the high strength can be maintained under the conditions of the heat cycle as well as the use at a high temperature.

According to the first aspect of the present invention, the strength of the matrix resin can be improved while maintaining the insulating property by using a powder having a volume resistivity of 10 ¹⁰ Ωcm or more as a filler mixed with the adhesive. . Here, by setting the filling ratio of the filler to 5 to 85% by volume, the strength of the insulating heat-resistant adhesive can be greatly improved. As the filler, it is particularly preferable to use insulating ceramic powder such as alumina or glass powder such as silica or silica glass.

The particle shape of the powder to be filled in the matrix resin is preferably a non-spherical powder such as a needle or flake. This is because by making the shape of the filler particles non-spherical such as needle-like or flake-like, the shear strength of the matrix resin can be greatly improved as compared with the case of a substantially spherical shape. Here, the aspect ratio (the ratio of the major axis to the minor axis) of the powder particles used as the filler is desirably 4 or more. That is, by setting the aspect ratio to 4 or more, the entanglement between the filler particles becomes large, and as a result, the strength of the adhesive can be greatly improved. However, in the above invention, a substantially spherical powder can be used in combination with a non-spherical powder.

Thus, according to the first invention, heat resistance,
By fixing the electrode member with an insulating heat resistant adhesive with excellent heat cycle resistance and adhesiveness, durability is improved, and severe heat cycles such as continuous use at high temperatures, rapid temperature rise, and rapid cooling Even in the use below, it is possible to prevent the problem that the electrode member comes off or the position shifts. Since the insulating heat-resistant adhesive of the present invention has a specific resistance of 10 ¹⁰ Ωcm or more, there is no fear of short-circuiting in the electric circuit even if the adhesive comes into contact with an external circuit of the heater.

According to a second aspect of the present invention, there is provided a heater comprising a heating resistor provided on the surface or inside of a substrate, and an electrode member joined to an end of the heating resistor, wherein the electrode member is heated by using a conductive paste. After joining to the resistor, the electrode member is fixed and reinforced by using the insulating heat-resistant adhesive specified in the first invention. That is, since the electrode member is fixed and reinforced with the insulating heat-resistant adhesive after the electrode member is electrically connected to the heating resistor with the conductive paste, the insulating heat-resistant adhesive may be mixed into the conductive paste. However, it is possible to prevent a poor electrical contact between the electrode member and the heating resistor.

According to a third aspect, in the heater according to the first or second aspect, a heating resistor is provided on the surface of the heater via an insulating layer, and an electrode member is joined to an end of the heating resistor. It is characterized by a heat roller. That is, the electrode member is fixed with the insulating heat-resistant adhesive specified in the first invention.
Reinforcement causes a problem that the electrode member may be displaced or fall off even under a condition of high temperature use or heat cycle, or even when a large force is applied to the electrode member from the outside. Can be prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described mainly with respect to a fixing heat roller. However, the insulating heat-resistant adhesive of the present invention is not limited to the category of the heat roller for fixing, a technical field in which an insulating adhesive requiring heat resistance is required, for example, for an electrode member of a sheet heating element. It can be applied to fixing and the like.

As shown in FIG. 1, the fixing heat roller of the present invention includes an insulating layer 2 on an inner peripheral surface of a cylindrical body 1 made of a metal pipe, and a heating resistor 3 is formed on the insulating layer 2. An electrode member 5 is fixed to the end of the heating resistor 3 using a conductive paste 4, and a release layer 6 is provided on the outer peripheral surface of the cylindrical body 1. Although only one end is shown in FIG. 2B, the electrode members 5 are similarly fixed to both ends.

The electrode member 5 has a lid shape that closes the hollow hole of the cylindrical body 1, has a protruding portion formed at the center, and has an end surface serving as a sliding surface 5a with the power supply member. When the fixing heat roller is used, the power supply member is brought into contact with the sliding surface 5a of the electrode member 5 provided at the end while rotating the cylindrical body 1, and the power is supplied while sliding. , The heating resistor 3 can be energized to generate heat.

Then, at the joint of the energizing terminal member 5,
The durability is enhanced by reinforcing with a heat-resistant adhesive 8 described in detail later.

As another embodiment, as shown in FIG. 2, a heater in which a heating resistor 12 is provided on the surface of a base 11 and an electrode member 13 is joined to an end of the heating resistor is also used in the present invention. The invention is very effective.

Here, the insulating adhesive is 5 to 85% by volume of a filler having a volume resistivity of 10 ¹⁰ Ωcm or more, and the remainder is a matrix. Is 2000 kgf / mm ² or less, the elongation is 10% or more, and the specific resistance is 10 ¹⁰ Ωcm or more.

First, the matrix is characterized by using an organic resin having a 5% weight loss temperature of 180 ° C. or higher. This is because the heat resistance of the resin is generally evaluated at a temperature of 5% (or 3% to 10%) weight loss, and at least 180 ° C. or more in consideration of the use conditions of a heat roller for fixing and other planar heaters. 5% of
This is because sufficient high-temperature durability can be obtained when a resin having a weight reduction temperature is used.

Here, a method of measuring the 5% weight loss temperature of the resin will be briefly described. First, when the form before use is a varnish-like resin, the evaporation of the solvent and the curing of the resin are completed in advance.

In general, thermogravimetric analysis (TG) is used for measuring the 5% weight loss temperature. That is, the resin serving as a sample is heated at a constant heating rate (1 to 10 ° C./min) in the atmosphere, and the weight at that time is sequentially measured. The temperature at the time when the weight is reduced by 5% with respect to the initial weight is the 5% weight reduction temperature of the resin.

Further, the elastic modulus of the organic resin is 2000 k.
It is characterized by a gf / mm ² or less and an elongation of 10% or more. This is because by setting the elastic modulus to 2000 kgf / mm ² or less and the elongation to 10% or more, it absorbs the stress generated when two or more kinds of members having different thermal expansions are joined to each other. As a filler to be mixed with the adhesive, a powder having a volume resistivity of 10 ¹⁰ Ωcm or more such as an insulating ceramic powder such as alumina or a glass powder such as silica or silica glass can be used. It is characterized in that it is used. This means that the volume resistivity is 1
This is because the use of a powder of 0 ¹⁰ Ωcm or more can improve the strength of the matrix resin while ensuring insulation.

Further, the filling ratio of the filler is desirably 5 to 85% by volume based on the solid content of the matrix resin. The reason is that when the content of the filler contained in the adhesive is 5% by volume or less, contact and entanglement between the filler particles become difficult, and the shear strength of the adhesive is not improved. If the content of is more than 80% by volume, the content of the matrix component responsible for adhesion becomes relatively small, so that high strength cannot be maintained. In addition, when the content of the filler is 80% by volume or more, there arises a problem that the paste property of the adhesive deteriorates.

For these reasons, the content of the filler is preferably 5 to 80% by volume based on the solid content of the adhesive.

The particle shape of the filling powder to be filled in the matrix resin is desirably a non-spherical powder such as a needle or flake. This is because, by making the shape of the filler particles non-spherical such as needle-like or flake-like, the entanglement between the filler particles becomes larger than in the case of a substantially spherical shape, and as a result, the shear strength of the adhesive increases. This is because it can be improved. However, in the above invention, a substantially spherical powder may be used in combination with the non-spherical powder.

Further, as the organic resin used as the matrix, polyimide, polyamide imide, bismaleimide, epoxy resin, silicone resin, fluorine resin, phenol resin, polybenzimidazole and the like can be used. It is preferable that the organic resin has an imide bond.

This is because resins having a molecular structure having an imide bond, such as polyimide and polyamideimide, are particularly excellent in heat resistance among organic resins. Thereby, an insulating heat-resistant adhesive excellent in heat resistance can be formed.

Next, the case where polyimide is used as a matrix in the method for producing an insulating heat-resistant adhesive of the present invention will be described.

First, the polyimide resin used as the matrix of the adhesive is a hardly soluble resin which does not dissolve except for concentrated sulfuric acid. Therefore, polyamic acid, which is a precursor of polyimide, is mixed with a suitable solvent, for example, N-methyl-2-.
Pyrrolidone (NMP) and tetrahydrofuran (THF)
Etc. to make a varnish. The varnish is mixed and kneaded with a filler at a desired volume fraction to form a paste. When kneading, it is desirable to use a kneader such as a three-roller mill.

Next, a method of using the insulating heat-resistant adhesive of the present invention will be described.

The adhesive paste prepared as described above is applied between the adherends, and then the solvent is evaporated in air or a nitrogen atmosphere at room temperature to 400 ° C., and a curing reaction is caused to occur. An insulating heat-resistant adhesive excellent in heat resistance, heat cycle property and adhesiveness can be formed.

As described above, according to the present invention, durability is improved by fixing the electrode member with the above-mentioned insulating heat-resistant adhesive having excellent heat resistance, heat cycle resistance, and adhesion. It is possible to prevent the problem that the electrode member falls off or shifts even if the electrode member is used under a severe heat cycle such as rapid temperature rise and rapid cooling.

Further, at the time of actual joining, as shown in FIG.
After joining, it is preferable to fix and reinforce using the insulating heat-resistant adhesive 8. Thereby, there is no possibility that the insulating heat-resistant adhesive 8 is mixed into the conductive paste 4, and it is possible to prevent a poor electrical contact between the electrode member 5 and the heating resistor 3.

Further, by applying the present invention to a fixing heat roller as shown in FIG. 1, the reliability of the electrode portion can be greatly improved. That is, in the heat roller, the cylindrical body 1, the heating resistor 3, the electrode member 5
However, since the materials of the electrode members 5 are different from each other, stress may be concentrated on the joints of the electrode members 5 under the conditions of the heat cycle, which may cause a problem that the electrode members 5 may fall off or displace. According to this, the electrode member 5 can be firmly fixed, and it is possible to prevent the problem that the electrode member 5 drops off or shifts even when heat or a large force is applied during use. it can.

Since the edge heat-resistant adhesive 8 has a specific resistance of 10 ¹⁰ Ωcm or more, even when the insulating heat-resistant adhesive 8 is applied to the surface of the heating resistor 3, 3 does not electrically affect the pattern and the resistance distribution, and even when the cylindrical body 1 and the electrode member 5 are in contact with each other via the insulating heat-resistant adhesive 8, the cylindrical body 1 and the electrode member 5 are not affected. Never short circuit.

That is, when the electrode member 5 is joined to the end of the heating resistor 3 using the conductive paste 4 and the joining strength is insufficient, the insulating heat-resistant adhesive 8 of the present invention is used. The electrode member 5 need only be reinforced, and there is no need to newly secure a portion to which the reinforcing adhesive is applied, and the design can be made compact.

[0042]

EXAMPLE 1 First, an insulating heat-resistant adhesive 8 was prepared using several types of resins having different 5% weight loss temperatures in a matrix, and the electrode member 13 of the heater shown in FIG. The bonding strength of the electrode member after being left in the atmosphere was measured. In addition, a silica powder was used as a filler for the insulating heat-resistant adhesive, and the mixing ratio was 5%.
0% by volume.

The results are shown in Table 1. It can be seen that a sufficient bonding strength can be obtained by using an organic resin having a 5% weight loss temperature of 180 ° C. or higher.

[0044]

[Table 1]

Example 2 Next, an insulating adhesive was prepared by changing the elastic modulus and elongation of the organic resin used as the matrix of the insulating heat-resistant adhesive 8, and the electrode member 13 of the heater shown in FIG. 2 was fixed. After performing a heat cycle test between room temperature and 200 ° C., the joining strength of the current-carrying terminal member 5 was measured.

As a filler for the insulating heat-resistant adhesive 8, 50% by volume of silica powder was used as in Example 1. Also, the base 1
Reference numeral 1 denotes aluminum coated with a polyimide resin, the heating resistor 12 is obtained by mixing a conductive material made of silver powder with a matrix component made of lead glass, and the electrode member 13 is made of brass.

The results are shown in Table 2. By using an organic resin having an elastic modulus of 2000 kgf / mm ² or less and an elongation of 10% or more as a matrix of the insulating heat-resistant adhesive, durability in a heat cycle was improved. It can be greatly improved.

[0048]

[Table 2]

Example 3 Next, an insulating heat-resistant adhesive was prepared by changing the mixing ratio of the filler mixed with the insulating heat-resistant adhesive 8, and the electrode member 13 of the heater shown in FIG. 2 was fixed. Was measured. In addition,
The filler was silica powder.

The results are shown in Table 3, and it can be seen that when the mixing ratio of the filler is 5 to 85% by volume, a sufficient adhesive strength can be obtained.

[0051]

[Table 3]

Example 4 Next, in the heater shown in FIG. 2, conduction was established between the electrode member 13 and the heating resistor 12 with a conductive paste, and the electrode member was reinforced with the insulating heat-resistant adhesive of the present invention. The heater was manufactured by changing the curing order of the conductive paste and the insulating heat-resistant adhesive at this time, and a power resistance test was performed.

The results are as shown in Table 4. After the conductive paste was cured, the electrode member was reinforced with an insulating heat-resistant adhesive, so that the insulating paste was not mixed into the conductive paste. It can be seen that there is no danger of causing a power failure.

[0054]

[Table 4]

Example 5 Next, a heat roller for fixing shown in FIG. 1 was produced. The cylindrical body 1 is made of a metal pipe such as aluminum, iron, or stainless steel, and has a thickness of 0.2 to 3 mm and an inner diameter of 5 to 5 mm.
0 mm. The insulating layer 2 is made of an organic resin such as polyimide, polyamide imide, phenol, silicon, and borosiloxane. The thickness of the insulating layer 2 varies depending on the dielectric strength of the organic resin.
A thickness of 200 μm is preferred. The release layer 6 is made of fluororesin, silicon, or the like having excellent releasability from the toner.

Further, the heating resistor 3 uses a mixture of a conductive material and a matrix component. Ag, as a conductive material,
Metals such as Ni, Cr, Pd and carbon, or ReO ₂ ,
Alternatively, conductive ceramics such as metal arsenide, silicide, and nitride are used, and as a matrix component, an organic resin such as polyimide, or a lead-based glass, a phosphate-based glass,
Glass such as zinc oxide glass is used. The thickness of the heating resistor 3 is 5 to 100 μm. This means that the thickness is 5
If the thickness is less than μm, the resistance value becomes high and the dispersion tends to occur. On the other hand, if it exceeds 100 μm, it tends to peel off.

Further, the electrode member 5 has an electric resistivity of 10
A material having μΩ · cm or less and a melting point of 800 ° C. or more, specifically, brass, copper, iron, stainless steel, a copper alloy, or a material obtained by plating the surface of these metals with nickel or the like is used.

After the electrode member 5 was fixed to the heating resistor 3 using the conductive paste 4, the electrode member 5 was reinforced using an insulating heat-resistant adhesive 8 as shown in FIG. Then, the torque strength and the punching strength of the electrode member after being left in a 200 ° C atmosphere and after a heat cycle from room temperature to 200 ° C were measured.

The torque strength is a rotational force when the electrode member 5 starts idling with respect to the cylindrical body 1, and the pushing strength is a force on the sliding surface 5 a of the electrode member 5 with the power supply member 7. When an external force is applied vertically from the external direction, the electrode member 5
Is the magnitude of the external force when moving toward the inside of the cylindrical body 1.

The results are shown in Tables 5 and 6. It can be seen that the reinforcement of the electrode member 5 using the insulating heat-resistant adhesive 8 of the present invention not only increases the initial strength of the electrode portion, but also significantly improves the durability of the electrode portion.

[0061]

[Table 5]

[0062]

[Table 6]

[0063]

As described above, according to the first aspect of the present invention, there is provided a heater in which a heating resistor is provided on the surface or inside of a base, and an electrode member is joined to an end of the heating resistor. 5% to 85% by volume of a filler having 10 ¹⁰ Ωcm or more, the remainder being a matrix, 5% weight loss temperature of 180 ° C. or more, elastic modulus of 2000 kgf / mm ² or less, and elongation of 10%.
% Or more by applying heat or a large force during use by fixing and reinforcing the electrode member using an insulating heat-resistant adhesive having a specific resistance of 10 ¹⁰ Ωcm or more composed of an organic resin of at least 10%.
Even when the electrode member is used under severe heat cycle conditions, it is possible to prevent a problem caused by peeling of the bonding portion of the electrode member or displacement thereof.

Further, according to the second aspect of the invention, in the above heater, the electrode member is joined to the heating resistor with a conductive paste, and then the electrode member is fixed and reinforced with an insulating heat-resistant adhesive. There is no possibility that the insulating heat-resistant adhesive is mixed into the conductive paste, and it is possible to prevent a poor electrical contact between the electrode member and the heating resistor.

According to the third aspect of the present invention, there is provided a fixing heat roller in which a heating resistor is provided on a surface of a cylindrical body via an insulating layer, and an electrode member is joined to at least one end of the heating resistor. By satisfying the contents stipulated in the first and second aspects of the present invention, the electrode member can be displaced even under conditions of high temperature use or heat cycle, and even when a large force is applied to the electrode member from the outside. Wake up,
Problems such as dropping out can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a fixing heat roller of the present invention.

FIG. 2 is a perspective view showing a heater according to the present invention.

FIG. 3A is a side view showing a conventional fixing heat roller, and FIG. 3B is a sectional view taken along line xx in FIG.

[Explanation of symbols]

 1: Cylindrical body 2: Insulating layer 3: Heating resistor 4: Conductive paste 5: Electrode member 6: Release layer 7: Power supply member 8: Insulating heat resistant adhesive 11: Base 12: Heating resistor 13: Electrode member

Claims (3)

[Claims] 1. A heating resistor is provided on the surface or inside of a base,
In a heater in which an electrode member is joined to an end of the heating resistor, a filler having a volume specific resistance of 10 ¹⁰ Ωcm or more is used for 5 to 5 hours.
85% by volume, the remainder being a matrix, 5% Weight loss temperature is 180 ° C. or more, and elastic modulus is 2000 kgf / mm ²
Hereinafter, the specific resistance of an organic resin having an elongation of 10% or more is 1
A heater characterized in that the electrode member is fixed and reinforced by using an insulating heat-resistant adhesive of 0 ¹⁰ Ωcm or more. 2. The heater according to claim 1, wherein the electrode member is joined to the heating resistor with a conductive paste, and then the electrode member is fixed and reinforced using the insulating heat-resistant adhesive. 3. The heater according to claim 1, wherein the base is a cylindrical body, and a heating resistor is provided on the surface of the heater via an insulating layer, and an electrode member is joined to at least one end of the heating resistor. Fixing heat roller.