JPH08146804A - Heating roller for fixing - Google Patents

Abstract

PURPOSE: To provide a heating roller for fixing with high safety where electric shock is not caused even when a hand or a tool such as a driver comes in contact with the roller. CONSTITUTION: The heating roller for fixing 10 is pivotally supported to be rotated in a main body frame 10, and constituted by forming an insulating film 12 made of an insulating material such as silicone rubber on the outer peripheral surface of a roller main body 11 consisting of a cylindrical body made of aluminum, forming a resistance heating element 13 on the outer peripheral surface of the insulating film 12, forming an insulating layer 14 on the outer peripheral surface of the heating element 13, and further forming an adhesion preventing layer 15 on the outer peripheral surface of the insulating layer 14 from the outer peripheral surface of the roller to the outside successively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing heating roller provided with a resistance heating element on the outer peripheral surface of a roller body, and in particular, an insulating layer is formed on the outer peripheral surface of the resistance heating element to prevent electric shock and to ensure safety. It is about things that are designed to improve sex.

[0002]

2. Description of the Related Art Conventionally, an image recording apparatus using a toner such as a copying machine or a printer is provided with a recording mechanism, a fixing mechanism, a conveying mechanism, etc., and the recording mechanism conveys toner based on an image signal. After being attached to the recording medium, the fixing heating roller provided in the fixing mechanism heats and fixes the toner attached to the recording medium.

By the way, the heating roller for fixing has a heating element formed on the outer peripheral surface of the roller body so that it can be heated to a predetermined high temperature (for example, about 130 ° C.) in a short time during fixing. In addition, by supplying a driving voltage through the electrodes provided on the roller body, the heating element can generate heat. For example, in Japanese Unexamined Patent Publication No. 49-81041, a heating element having a plurality of thin heating lines folded back is provided on the outer peripheral surface of the roller body, and the heating element is provided outside the heating element.
A heat conductive layer made of metal such as stainless steel or aluminum is provided, and a thin film offset layer (adhesion prevention layer) made of a non-adhesive material such as Teflon to prevent the toner on the recording medium from adhering to the roller surface. And a heating roller for fixing the toner on the recording medium by heat generated by the heating element to eliminate unevenness of heat conduction in the heat conduction layer and by heat having a substantially uniform temperature distribution.

Recently, a carbon-based heating element such as carbon black or graphite, or a thin plate-shaped stainless heating element has been developed, and a heating element capable of uniformly generating heat is incorporated over the entire surface for fixing. It is common to configure a heating roller, and the heat conduction layer described above can be omitted.
Stable fixing process is possible.

[0005]

As described above, in the fixing heating roller described in Japanese Patent Laid-Open No. 49-81041, a metal heat conduction layer is formed on the outside of the heating element, and the heat conduction layer is formed on the outside thereof. Since only a thin film offset layer is formed,
When the hand accidentally touches the fixing roller, or when a sharp tool such as a driver collides with the fixing roller, the offset layer is easily damaged and the tool directly contacts the heating element through the heat conduction layer. In that case, there is a problem that the drive current supplied to the heating element may be electrocuted.

Further, when a heating element of carbon type or metal type such as stainless steel capable of generating heat on the whole surface is used for the fixing heating roller, a thin film-like peeling layer on which the toner hardly adheres is formed on the outer peripheral surface thereof. Since it is only being done, like the above,
When a sharp tool such as a screwdriver collides with the fixing heating roller during maintenance while the power is on, the anti-adhesion layer is easily scratched. There is a problem that the drive current that is being applied may cause an electric shock.

An object of the present invention is to provide a heating roller for fixing which is highly safe and does not receive an electric shock even when a tool such as a hand or a driver comes into contact with the heating roller.

[0008]

A fixing heating roller according to claim 1 is a roller body, a resistance heating element formed on an outer peripheral surface of the roller body, and a resistance heating element connected to the resistance heating element. An electrode for supplying electric power to the resistance heating element, and the electric power applied to the electrode causes the resistance heating element to generate heat. The heat causes the toner adhering to the recording medium to be melted by heating and fixed on the recording medium. In the heating roller for fixing, an insulating layer made of a material having excellent insulating property is formed on the outer peripheral surface of the resistance heating element. According to a second aspect of the present invention, in the heating roller for fixing according to the first aspect of the present invention, the insulating layer is made of a material having excellent thermal conductivity and is formed to a thickness of 400 μm or more.

According to a third aspect of the present invention, there is provided a fixing heating roller.
Alternatively, in the invention of claim 2, the insulating layer is made of ceramics. A fixing heating roller according to a fourth aspect is the fixing heating roller according to any one of the first to third aspects, in which a thin film conductor is provided on the outer peripheral surface of the insulating layer, and the conductor is electrically grounded. It was done. The fixing heating roller of claim 5 is any one of claims 1 to 3.
In the invention of the item (1), a thin-film conductor is provided on the outer peripheral surface of the insulating layer, and the conductor is set to a potential having a polarity opposite to that of the toner and an absolute value of about 1 V or less.

[0010]

In the fixing heating roller of the first aspect, since the insulating layer made of a material having excellent insulating property is formed on the outer peripheral surface of the resistance heating element, even when the fixing heating roller is touched by a hand or a tool. , There is no electric shock due to this insulating layer.

In the fixing heating roller of claim 2,
Since the insulating layer is made of a material having excellent thermal conductivity, the heat generated from the resistance heating element can be efficiently conducted to the toner on the recording medium and can be reliably fixed. Furthermore, since the insulating layer is formed to have a thickness of 400 μm or more, it is possible to ensure high safety conforming to international safety standards.

In the fixing heating roller of claim 3,
Since the insulating layer is made of ceramics, it is possible to manufacture a fixing heating roller which is lightweight and has excellent durability in addition to heat resistance and thermal conductivity.

In the heating roller for fixing according to claim 4,
Since a thin film conductor is provided on the outer peripheral surface of the insulating layer and the conductor is electrically grounded, even if the insulating layer is destroyed by a tool such as a driver colliding, the drive current of the resistance heating element Can be avoided to the ground side through this conductor, and high safety can be secured.

In the fixing heating roller of the fifth aspect,
Since a thin-film conductor is provided on the outer peripheral surface of the insulating layer and the conductor is set to have a polarity opposite to that of the toner and an electric potential of about 1 V or less in absolute value, it is generated on the surface of the fixing heating roller. Since static electricity can be erased, electrostatic offset can be prevented.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a fixing heating roller incorporated in a fixing mechanism provided in an image recording apparatus such as a copying machine or a printer. 1 and 2
As shown in FIG. 3, the fixing heating roller 10 is rotatably supported by the main body frame by a pivotal support mechanism (not shown), and an insulating material such as silicon rubber is formed on the outer peripheral surface of the roller main body 11 made of an aluminum cylindrical body. An insulating film 12 made of a material is formed, a resistance heating element 13 is formed on the outer peripheral surface of the insulating film 12, an insulating layer 14 is formed on the outer peripheral surface of the resistance heating element 13, and the outer peripheral surface of the insulating layer 14 is further formed. The adhesion prevention layer 15 is
The outer peripheral surface of the roller is sequentially formed.

The resistance heating element 13 is a heating element made of carbon black or a polyimide resin mixed with graphite. Here, this resistance heating element 13 is
It is also possible to use a thin plate-shaped metal heating element such as stainless steel.

The insulating layer 14 is made of alumina, which is one of ceramics having high thermal conductivity and insulating properties, and is formed by a sol-gel method, and has a thickness of about 400 μm. This alumina has a very high insulating property and a very high thermal conductivity of about 60 W / mK. Here, the thickness of about 400 μm is a thickness that is compliant with international safety standards and sufficient for enhancing safety. The adhesion preventing layer 15 has a thickness of about 10 to 20 μm, is made of a fluororesin such as Teflon coat, and has excellent heat resistance. During the fixing process, the toner on the recording medium P adheres to the roller side. It is designed to prevent you from doing so.

On the other hand, annular electrodes 16 and 17 are attached to the left and right ends of the resistance heating element 13 in the roller axial direction so as to contact the outer circumference of the resistance heating element 13. , 17 are configured to always contact a corresponding contact brush (not shown). Then, a drive voltage output from a drive circuit (not shown) is supplied to the resistance heating element 13 via these contact brushes and the electrodes 16 and 17,
The resistance heating element 13 has a predetermined fixing temperature, for example, about 120 °.
Generates heat at C to 130 ° C. By the way, the resistance heating element 13
Is in contact with the outer periphery of the roller body 11 through the insulating film 12, so that the insulation of the resistance heating element 13 with respect to the roller body 11 is ensured.

Next, the function of heating and fixing the toner attached to the recording paper P will be described. When the resistance heating element 13 is energized via the electrodes 16 and 17 and the resistance heating element 13 generates heat at the fixing temperature, the heat generation is transmitted to the insulating layer 14. Here, since the insulating layer 14 has excellent thermal conductivity, the amount of heat generated from the resistance heating element 13 is transferred to the adhesion preventing layer 15 on the outer side with almost no decrease. Since the anti-adhesion layer 15 is a thin film, the anti-adhesion layer 15 is heated by the amount of heat generated from the insulating layer 14, and the anti-adhesion layer 15 is heated.
The toner attached to the recording medium P conveyed while being in contact with is heated. Then, the heated toner is melted and fixed on the recording medium P.

By the way, even if a tool such as a hand or a screwdriver is accidentally brought into contact with the fixing heating roller 10 during maintenance by a service person, the resistance is increased by the insulating layer 14 having a thickness of 400 μm or more. Heating element 13
It is extremely safe because there is no electric shock to the drive current supplied to it. Further, especially when the tool is sharply collided with the fixing heating roller 10 by a tool such as a driver,
Even if the adhesion preventing layer 15 is scratched, the insulating layer 14 having a thickness of 400 μm or more is less likely to be broken, and the drive current supplied to the resistance heating element 13 is not electrocuted, which is very safe. .

Here, as shown in FIG. 3, the insulating layer 14A
The fixing heating roller 10A may be configured by forming a thin-film conductive layer 17 such as a copper foil between the and the adhesion preventing layer 15A and electrically grounding the conductive layer 17.
In this case, the tool with a sharp tip is the heating roller 10A for fixing.
Even if not only the adhesion preventing layer 15A but also the insulating layer 14A is destroyed due to a strong collision with the above, the driving current from the resistance heating element 13A will flow to the ground through the conductive layer 17, so that the safety is improved. More enhanced.

Further, when the toner is charged to a negative potential, as shown in FIG. 4, the conductive layer 17B is
May be configured to have a polarity opposite to that of the toner and an absolute value of about 1 V or less, for example, about +0.7 V, in which case the fixing heating roller 10B may be configured. Since static electricity generated on the surface of the roller 10B can be erased, electrostatic offset can be prevented. Here, the fixing heating roller 10B shown in FIG. 4 has the same configuration as that shown in FIG. 3 except that the conductive layer 17B is set to about + 0.7V.

The insulating layers 14 and 14A may be made of various ceramics having excellent thermal conductivity or insulating properties, or may be formed by applying water glass solvent and then drying it. Within the scope of the technical idea, various modifications may be made to the above-described embodiments based on existing technology or technology obvious to those skilled in the art. Of course, the present invention can be applied to various fixing heating rollers provided with the resistance heating element 13 on the outer peripheral surface of the roller body 11.

[0024]

According to the fixing heating roller of the first aspect,
Since the resistance heating element formed on the outer peripheral surface of the roller body and the electrodes formed on the resistance heating element are provided, and the insulating layer is further formed on the outer peripheral surface of the resistance heating element, the fixing heating roller is provided with a hand or a tool. Even if they come into contact with each other, the insulating layer does not cause an electric shock.

According to the fixing heating roller of the second aspect, since the insulating layer is made of a material having excellent thermal conductivity, the heat generated by the resistance heating element is efficiently transferred to the toner on the recording medium. It can be conducted and reliably fixed. Furthermore, the insulating layer is
Since it is formed with a thickness of 400 μm or more, it is possible to secure high safety conforming to international safety standards.

According to the fixing heating roller of the third aspect, since the insulating layer is made of ceramics, it is possible to manufacture a fixing heating roller which is lightweight and excellent in durability in addition to heat resistance and thermal conductivity. You can

According to the fixing heating roller of the fourth aspect, since a thin-film conductor is provided on the outer peripheral surface of the insulating layer and the conductor is electrically grounded, a tool such as a driver collides with it. Even if the insulating layer is destroyed, the drive current of the resistance heating element can be avoided to the ground side through this conductor, and high safety can be secured.

According to the fifth aspect of the heating roller for fixing, a thin film conductor is provided on the outer peripheral surface of the insulating layer, and the conductor has a polarity opposite to the potential of the toner and an absolute value of about 1 V or less. Since the potential is set, the static electricity generated on the surface of the fixing heating roller can be erased, so that the electrostatic offset can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a fixing heating roller.

FIG. 2 is a side view of a longitudinal section of a main part of a fixing heating roller.

FIG. 3 is a view corresponding to FIG. 2 according to the first modification.

FIG. 4 is a view corresponding to FIG. 2 according to a second modification.

[Explanation of symbols]

 10 Fixing Heating Roller 11 Roller Main Body 13 Resistance Heating Element 14 Insulating Layer 16 Electrode 17 Electrode

Claims (5)

[Claims] 1. A roller main body, a resistance heating element formed on an outer peripheral surface of the roller main body, and an electrode connected to the resistance heating element for supplying electric power to the resistance heating element. In the fixing heating roller, the resistance heating element is heated by the electric power applied to the electrodes, and the heat adheres the toner adhering on the recording medium to the toner to fix the toner on the recording medium. A fixing heating roller comprising an insulating layer formed on the outer peripheral surface and made of a material having excellent insulating properties. 2. The fixing heating roller according to claim 1, wherein the insulating layer is made of a material having excellent thermal conductivity and is formed to a thickness of 400 μm or more. 3. The fixing heating roller according to claim 1, wherein the insulating layer is made of ceramics. 4. The thin-film conductor is provided on the outer peripheral surface of the insulating layer, and the conductor is electrically grounded. A heating roller for fixing. 5. A thin-film conductor is provided on the outer peripheral surface of the insulating layer, and the conductor is set to a potential having a polarity opposite to that of the toner and an absolute value of about 1 V or less. The heating roller for fixing according to any one of claims 1 to 3.