JPH06258974A - Thermal fixing device - Google Patents

Abstract

PURPOSE:To attain reduction in the power consumption of a thermal fixing device and simultaneously to eliminate the need of preheating by arranging a flexible thin film resistor in parallel with a heating roller in an axial direction and selectively supplying power. CONSTITUTION:The heating roller 1 has the flexible thin film resistor 13 composed of plural belt-like or straight line-like resistance groups electrically insulated from each other and arranged in parallel in the axial direction and when a current at is selectively supplied to the flexible thin film resistor 13 located in the vicinity of the nipping region of the heating roller 1 being contact with a pressure roller 2, in a state where the pressure roller 2 is in contact with the heating roller 1 and both rollers are rotated, the flexible thin film resistor 13 instantaneously generates heat with a heating value corresponding to the resistance value of the resistor 13 and the nipping region is quickly heated to thermally fix a developer T out a recording medium S with reduced power consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device, and more particularly to a heat fixing device for heating and fixing an object to be fixed on the surface of a recording medium.

[0002]

2. Description of the Related Art A hard copy device based on an electrophotographic process, that is, a copying machine, a laser beam printer, a plain paper facsimile, etc., is a main output device of office automation equipment. The increase in power consumption of these output devices has been particularly large in recent years, and low power consumption of these output devices is an important issue, but most of the power consumption of these output devices is heat fixing in which a developer is heat-fixed on a recording medium. It is consumed by the device.

In a conventional heat fixing device, a heating roller in which a rod-shaped heater, a halogen lamp or the like is inserted as a heating element inside a metal hollow cylindrical body which is a good conductor of heat, and a recording medium is circumscribed to the heating roller to fix a recording medium. It is configured by combining with a pressure roller that applies pressure, and thermal fixing is performed by passing a recording medium having an object to be fixed attached to the outer contact portion (nip area) of both rollers.

[0004]

In the above-mentioned conventional heat fixing device, the heating roller is formed of a metal hollow cylindrical body which is a good conductor of heat, and a rod-shaped heater, a halogen lamp or the like is disposed therein as a heating element. Therefore, there is a problem that the heating roller becomes large in size and the heat efficiency is poor and the power consumption is large. Specifically, the thermal efficiency of the conventional heat fixing device is extremely low and is 10% or less. For example, when the surface temperature of the heating roller is required to be about 160 ° C, the heating element inserted in the inside has a temperature of 800 ° C or more. Temperature was required and most of the heat was lost as radiation and conduction losses.

Further, since the heating roller has a large heat capacity and the heating roller and the heating element are separate bodies, a preheating time of several minutes is required before the temperature rises to a predetermined temperature at which thermal fixing can be performed when the output device is started. There was a problem.

In view of the above points, an object of the present invention is to externally contact a pressure roller of a heating roller having a flexible thin film resistor composed of a resistor group insulated from each other and arranged in parallel in the axial direction. It is an object of the present invention to provide a thermal fixing device in which a flexible thin film resistor located near the nip region is selectively energized to generate heat, thereby reducing power consumption and eliminating preheating. .

Another object of the present invention is to provide a nipping area of a heating belt having a flexible thin film resistor composed of a resistor group which is insulated from each other and arranged in parallel in a cylindrical direction, and which is circumscribed with a pressure roller. It is an object of the present invention to provide a thermal fixing device in which a flexible thin film resistor located in the vicinity is selectively energized to generate heat, thereby reducing power consumption and eliminating the need for preheating.

[0008]

The heat fixing device of the present invention comprises:
In a thermal fixing device for heating and fixing an object to be fixed on the surface of a recording medium, a flexible thin film resistor composed of a plurality of linear strip-shaped or linear thin line-shaped resistors that are insulated from each other and arranged in parallel in the axial direction. A current is selectively applied to a heating roller having a body on the surface side, a pressure roller circumscribing the heating roller, and a flexible thin film resistor located near the nip region of the heating roller circumscribing the pressure roller. And a contact power supply means for supplying.

The heat fixing device of the present invention is a heat fixing device for heating and fixing an object to be fixed on the surface of a recording medium,
A heating belt having on its surface side a flexible thin-film resistor composed of a plurality of linear strip-shaped or linear thin-line-shaped resistor groups which are insulated from each other and arranged in parallel in the cylinder direction, and a heating belt circumscribing the heating belt. It has a pressure roller and a contact power supply means for selectively supplying an electric current to the flexible thin film resistor located in the vicinity of the nip region of the heating belt which is in contact with the pressure roller.

[0010]

In the heat fixing device of the present invention, the heating roller is insulated from each other and the flexible thin film resistor composed of a plurality of linear strip-shaped or linear thin-line resistor groups arranged in parallel in the axial direction is surfaced. A flexible thin film resistor located in the vicinity of the nip region of the heating roller having the pressure roller circumscribing the heating roller and contacting the power feeding means circumscribing the pressure roller. By selectively supplying an electric current to the developer, the developer is thermally fixed on the recording medium.

Further, in the heat fixing device of the present invention, the flexible thin film resistor is composed of a plurality of linear strip-shaped or linear thin-lined resistor groups in which the heating belts are insulated from each other and arranged in parallel in the cylinder direction. A flexible thin film which is located near the nip region of the heating belt where the contact power supply means is in contact with the pressure roller while the pressure roller is in contact with the heating belt and both rollers are rotating. By selectively supplying an electric current to the resistor, the developer is thermally fixed on the recording medium.

[0012]

The present invention will be described in detail with reference to the drawings.

FIGS. 1, 2 and 3 are a longitudinal sectional view, a side view and a perspective view showing a heat fixing device according to a first embodiment of the present invention. The heat fixing device of this embodiment includes the heating roller 1.
And a pressure roller 2 are arranged so as to be in pressure contact with each other by a pressure mechanism (not shown).

The heating roller 1 includes a shaft member 11 and a shaft member 1.
Heat-resistant elastomer layer 12 applied to the peripheral surface of 1 in a layer thickness
And a plurality (16 in the figure) of flexible thin-film resistors 13 that are insulated from each other around the heat-resistant elastomer layer 12 and are attached in a belt-like shape in the axial direction, and cover the periphery of the flexible thin-film resistor 13. Of the heat-resistant protective film 14 and the pair of conductive contact members 15a and 15b contacting both ends of the flexible thin film resistor 13.
It consists of and.

The shaft member 11 is formed of a metal such as aluminum or stainless steel having high bending rigidity or a synthetic resin into a hollow cylindrical body.

The heat-resistant elastomer layer 12 is made of tetra-fluoro-ethylene-propylene-based, vinylidene fluoride-based,
It is formed by molding fluorine-based and silicone-based heat-resistant elastomer materials such as silicone-based, fluoro-silicone-based, etc.

The flexible thin film resistor 13 is a rubber / synthetic resin thin film resistor, a metal thin film resistor, or the like, and has a width about the width of the nip area formed by the pressure contact between the heating roller 1 and the pressure roller 2. The width is smaller than that. As the rubber / synthetic resin thin film resistor, a synthetic resin film in which a powdery or fibrous metal-based current-carrying material or a carbon-based current-carrying material is combined is attached to the peripheral surface of the heat-resistant elastomer layer 12 at equal intervals. Alternatively, a powdery or fibrous coating material mixed with a metal-based current-carrying material or a carbon-based current-carrying material may be applied to the peripheral surface of the heat-resistant elastomer layer 12 at equal intervals and dried. As the metal-based thin film resistor, a metal-based resistance film of nickel-chromium or the like is vapor-deposited or thick-film printed on the surface of the heat-resistant elastomer layer 12 at equal intervals, or a metal-based resistance film is equally spaced. For example, the heat-resistant elastomer layer 12 may be coated with a synthetic resin film vapor-deposited or thick-film printed on the peripheral surface of the heat-resistant elastomer layer 12.

The heat-resistant protective film 14 is formed by coating a synthetic resin film such as polyimide on the flexible thin film resistor 13 or by coating synthetic resin such as Teflon or silicone thinly on the flexible thin film resistor 13. It is formed by a method such as drying by drying. The heat-resistant protective film 14 prevents the developer (fixed material) T from adhering to the heating roller 1 and also serves as an insulating film. Particularly, insulation is performed by entering between the flexible thin film resistors 13 arranged in parallel in the axial direction in a strip shape.

The energizing contact members 15a and 15b are formed of a leaf spring member made of metal or conductive resin, a conductive brush or the like, and as shown in FIG. 2, both end portions of the heating roller 1 are protected against heat resistance. The flexible thin film resistor 13 in the portion where the film 14 is removed is elastically contacted so as to correspond to the vicinity of the nip region when viewed in the circumferential direction. If there is a risk that the flexible thin film resistor 13 will be worn when the energizing contact members 15a and 15b are brought into direct contact with both ends of the flexible thin film resistor 13 to energize, It is desirable to strengthen both ends of the flexible thin film resistor 13 with a metal such as brass.

The pressure roller 2 is composed of a shaft member 21 and an elastomer layer 22 deposited thereon in a layer thickness.

The shaft member 21 is formed of a metal such as aluminum or stainless steel having a high bending rigidity or a synthetic resin into a hollow cylindrical body.

The elastomer layer 22 is formed by molding an elastomer material made of elastic synthetic resin.

The heating roller 1 and / or the pressure roller 2 are rotatably driven in a direction indicated by an arrow by a driving source (not shown).

Next, the operation of the thermal fixing device of the first embodiment thus constructed will be described.

When the recording medium S having the developer T adhered to the surface thereof is fed into the nip region which is rotated at a constant circumferential speed while pressing the heating roller 1 and the pressure roller 2 into contact with each other, the recording medium S becomes The sheet is fed while being pressed against the pressure roller 2.

In this state, the energizing contact members 15a and 1
When electricity is applied to 5b, the flexible thin film resistor 13 located near the nip region of the heating roller 1 with which the pressure roller 2 is in pressure contact.
A current selectively flows through the flexible thin film resistor 13, and the flexible thin film resistor 13 instantly generates heat with an amount of heat corresponding to its resistance value, and the nip region quickly becomes high in temperature.

Therefore, the recording medium S passing through the nip region is heated by the heating roller 1 contacting the surface of the recording medium S to heat the developer T, and at the same time the heat-melted developer T is added. The pressure roller 2 pressurizes the surface of the recording medium S with a uniform contact pressure so that the recording medium S is reliably fixed. The recording medium S on which the developer T has been fixed is sent out of the thermal fixing device as the heating roller 1 and the pressure roller 2 rotate.

4 and 5 are a vertical sectional view and a perspective view showing a heat fixing device according to a second embodiment of the present invention. In the thermal fixing device of this embodiment, the pressure roller 5 is pressed by the pressure mechanism (not shown) via the heating belt 4 and the pressure roller 44.
It is arranged so as to be in pressure contact with.

The heating belt 4 has a flexible thin-film resistor 42 on a base film 41 made of a heat-resistant flexible synthetic resin film such as polyimide or linear polyester.
Are insulated from each other, and a large number of thick films are printed linearly in the cylinder direction, and are fused and formed into an endless belt by ultrasonic bonding. The heating belt 4 is stretched between a pair of driving rollers 43a and 43b, and a pressing roller 44 arranged in parallel between the driving rollers 43a and 43b is in contact with the inner surface side, and the flexible thin film resistor is Body 42
A pair of energizing contact rollers 45 (only one of which is visible in FIG. 5) is in contact with both ends of the roller. The heating belt 4 is superior to the heating roller 1 in the heat fixing device of the first embodiment in mass productivity and contributes to downsizing of the heat fixing device.

The drive rollers 43a and 43b and the pressing roller 44 are made of aluminum having high bending rigidity.
It is formed of a metal such as stainless steel or a synthetic resin into a cylindrical body and a cylindrical body.

The energizing contact roller 45 is formed of a roller member made of metal, conductive resin, or the like so that both ends of the flexible thin film resistor 42 of the heating belt 4 correspond to both ends of the pressing roller 44. In other words, it is elastically contacted so as to correspond to the vicinity of the nip region when viewed in the circumferential direction. If there is a possibility that the flexible thin film resistor 42 will be worn when the energizing contact rollers 45 are directly contacted with the both ends of the flexible thin film resistor 42 to cause the flexible thin film resistor 42 to wear, It is desirable to strengthen both ends of the thin film resistor 42 with a metal such as brass.

Since the pressure roller 5 has the same structure as the corresponding pressure roller 2 in the heat fixing device of the first embodiment shown in FIGS. 1 to 3, the corresponding shaft member 5 is used.
1 and the elastomer layer 52 will not be described in detail.

Next, the operation of the heat fixing device of the second embodiment having the above structure will be described.

While the pressure roller 5 is pressed against the pressing roller 4 via the heating belt 4, the heating belt 4 and the pressure roller 5
When the recording medium S having the developer T adhered to the surface thereof is fed into the nip region where the and are rotated at the constant circumferential speed, the recording medium S is fed while being pressed between the heating belt 4 and the pressure roller 5. Will be.

When the energizing contact roller 45 is energized in this state, the current selectively flows only in the flexible thin film resistor 42 located in the vicinity of the nip region where the pressure roller 5 is in pressure contact,
The flexible thin film resistor 42 instantly generates heat with an amount of heat according to its resistance value, and the nip region quickly becomes high in temperature.

Therefore, the recording medium S passing through the nip region is thermally melted by the heating belt 4 coming into contact with the surface of the recording medium S, and at the same time, the thermally melted developer T is added. The pressure roller 5 pressurizes the surface of the recording medium S with a uniform contact pressure so that the recording medium S is reliably fixed. The recording medium S on which the developer T has been fixed is sent out of the heat fixing device as the heating belt 4 and the pressure roller 5 rotate.

In each of the above embodiments, the heating roller 1 is provided with the strip-shaped flexible thin film resistor 13 and the heating belt 4 is provided with the linear flexible thin film resistor 42. It is needless to say that the linear flexible thin-film resistor 1 may be provided on the heating belt 4 and the strip-shaped flexible thin-film resistor may be provided on the heating belt 4.

Although the heat-resistant protective film 14 is provided on the heating roller 1 and is not provided on the heating belt 4, the heat-resistant protective film may not be provided on the heating roller 1 and may be provided on the heating belt 4. Needless to say.

[0039]

As described above, according to the present invention,
In the vicinity of the nip region circumscribing the pressure roller of the heating roller having a flexible thin film resistor composed of a plurality of linear strip-shaped or linear thin-line-shaped resistor groups that are insulated from each other and arranged in parallel in the axial direction. By selectively energizing and heating only the flexible thin film resistor located, heat radiation loss and conduction loss are extremely reduced, thermal efficiency is dramatically improved, and power consumption is significantly reduced. In addition to that, there is an effect that preheating can be eliminated.

Further, according to the present invention, there is provided a heating belt having a flexible thin film resistor composed of a plurality of linear strip-shaped or linear thin line-shaped resistor groups which are insulated from each other and arranged in parallel in a cylindrical direction. , By selectively energizing and heating only the flexible thin film resistor located near the nip area circumscribing the pressure roller, heat radiation loss and conduction loss are extremely reduced and thermal efficiency is epoch-making. And the power consumption can be significantly reduced, and preheating can be eliminated.

[Brief description of drawings]

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

FIG. 2 is a side view showing the configuration of the heat fixing device of the first embodiment.

FIG. 3 is a perspective view showing the configuration of the heat fixing device of the first embodiment.

FIG. 4 is a vertical cross-sectional view showing the configuration of a heat fixing device according to a second embodiment of the invention.

FIG. 5 is a perspective view showing a configuration of a heat fixing device according to a second embodiment.

[Explanation of symbols]

 1 Heat Roller 2 Pressure Roller 4 Heating Belt 5 Pressure Roller 11 Shaft Member 12 Heat Resistant Elastomer Layer 13 Flexible Thin Film Resistor 14 Heat Resistant Protective Film 15a, 15b Conductive Contact Member 21 Shaft Member 22 Elastomer Layer 41 Base Film 42 Flexible thin film resistors 43a and 43b Drive roller 44 Pressing roller 45 Conductive contact roller 51 Shaft member 52 Elastomer layer

Claims (3)

[Claims] 1. A thermal fixing device for heating and fixing an object to be fixed on the surface of a recording medium, comprising a plurality of linear strip-shaped or linear thin-line-shaped resistor groups which are insulated from each other and arranged in parallel in an axial direction. A heating roller having a flexible thin film resistor on the surface side; a pressure roller circumscribing the heating roller; and a flexible thin film resistor located near the nip region of the heating roller circumscribing the pressure roller. A thermal fixing device having a contact power supply means for selectively supplying an electric current. 2. A thermal fixing device for heating and fixing an object to be fixed on the surface of a recording medium, comprising a plurality of linear strip-shaped or linear thin-line-shaped resistor groups which are insulated from each other and arranged in parallel in a cylindrical direction. A heating belt having a flexible thin film resistor on the surface side, a pressure roller circumscribing the heating belt, and a flexible thin film resistor located near the nip region of the heating belt circumscribing the pressure roller. A thermal fixing device having a contact power supply means for selectively supplying an electric current. 3. The heat fixing device according to claim 1, wherein the flexible thin film resistor is covered with a heat resistant protective film.