JP2001056617A - Heat fixing device and image forming device utilizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply a heat fixing device to an on demand printer with saving energy and shortening time for warming up. SOLUTION: This heat fixing device 22 is constituted by being provided with a heating roll 23 with a surface that is coated by a releasing material layer and installed with a heating source 35 inside, a press roll 24 that is in a pressurized contact with the heating roll 23, constituted so that recording paper carrying an unfixed image is passed through a nip part 31 with the heating roll 2 and with its surface coated by a releasing material layer, a temperature detecting means (temperature sensor) 41 detecting a surface temperature of the heat roll 23 and a temperature control means (CPU) controlling energizing to the heating source 35 based on a detected result of the temperaure detecting means 41. A member with thickness that is <=0.3 mm is utilized as metal core of the heating roll 24 and at the same time, the temperature detecting sensor 41 where thermal time constant is <=0.8 second is utilized.

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 used for an image forming apparatus such as a printer or a copying machine using an electrophotographic method, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer or a copier using this type of electrophotographic system, an electrostatic latent image is formed on a photosensitive drum based on image information, and the electrostatic latent image is formed. An image is formed by developing the image with a developing device to form a toner image, transferring the toner image onto a recording sheet, and fixing the toner image on the recording sheet by a heat fixing device. . The heat fixing device is driven to rotate while the heating roll and the pressure roll are pressed against each other, and by passing the recording paper on which the toner image has been transferred to the nip portion between the heating roll and the pressure roll,
The toner image is fixed on the recording paper by heat and pressure.

In the case of the above-mentioned heat fixing apparatus, generally, a heating roll is formed by laminating an elastic layer or a release material layer on the surface of a metal core having a predetermined thickness.
The heating roll is configured such that a heating source such as a halogen lamp is disposed inside a metal core, and is heated from the inside by the heating source. As the metal core of the heating roll, an aluminum base tube (thickness: about 1 mm) excellent in workability and heat conductivity was mostly used.

[0004]

However, the above-mentioned prior art has the following problems. That is, when an aluminum pipe (thickness = 1 mm) having excellent workability and heat conductivity is used as the metal core of the heating roll in the heat fixing device, the heat fixing device has recently been used. There is a problem that it is difficult to reduce the required power consumption and the warm-up time, that is, it is difficult to raise the standby temperature in a short time.

More specifically, in recent years, energy saving has been called for, and in image forming apparatuses such as printers and copiers, reduction of power consumption has become an issue. In particular, in the standby mode, the heat fixing device consumes 80% of the entire power, and there is a problem that excessive power is consumed even though the printing operation is not actually performed. .

In order to solve such a problem, a method may be considered in which the power supply to the heat fixing device is cut off in the standby mode. However, this method requires a long warm-up time until the printing operation is actually started. It has a new problem of passing.

Further, in order to solve the above-mentioned problems, a method for compensating for this drawback has already been put to practical use by replacing a heating roll used for heat fixing with a thin film and a heating source pressed against the film. I have.

However, this method requires a plurality of rollers for circulating a thin film, a heating source pressed against the film, and the like, which leads to another problem that the structure becomes complicated and the cost increases. Have a point.

Therefore, it has been considered that a conventional technique using a heating roll can be used to reduce the warm-up time and reduce the cost at a stretch by making the heating roll very thin.

[0010] However, in the prior art, most of the use of an aluminum tube excellent in workability and heat conductivity as the metal core of the heating roll,
Aluminum tube has a very low flexural modulus compared to iron, SUS, etc., so when it is used for a heating roll of a heat fixing device, the wall thickness t when fixing A4 size paper is used.
The minimum thickness is t = 0.5 mm and the thickness t when fixing A3 size paper is about 0.7 mm.
For this reason, it takes about 25 to 30 seconds to warm up the heating roll to a predetermined fixing temperature, or it is necessary to set the fixing temperature to be high, and it is crucial to shorten the warm-up time. Was not a great solution.

In the case where a thin metal core is used as the heating roll, when the heating roll is heated by a heating source disposed inside the metal core, the surface of the heating roll is heated. Since the temperature rises sharply, the temperature detection by the temperature detecting means is delayed, and the surface temperature of the heating roll excessively rises abnormally, causing a problem that a thermostat malfunctions or a halftone image quality is deteriorated. I have.
Further, when the surface temperature of the heating roll suddenly rises, the margin of the set temperature of the heating roll becomes small, or the temperature detection by the temperature detecting unit is delayed, and as shown in FIG. There is also a problem that the generated drift increases. Note that FIG.
Is a heating roll using a 0.2 mm thick iron core,
It is a graph which shows the temperature change at the time of controlling so that it may become 173 degreeC of control temperatures.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to enable energy saving, shorten the warm-up time, and reduce power consumption. An object of the present invention is to provide a heat fixing device applicable to a demand printer and an image forming apparatus using the same.

The second object is to set a low fixing temperature, to enable accurate temperature control, and to prevent image defects from occurring. And an image forming apparatus using the same.

[0014]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention according to claim 1 comprises a heating roll having a surface covered with a release material layer and a heating source disposed inside. ,
Arranged so as to pass the recording medium carrying the unfixed image in the nip portion that is pressed against the heating roll,
A pressure roll having a surface coated with a release material layer, temperature detection means for detecting a surface temperature of the heating roll, and temperature control for controlling energization to a heating source based on a detection result of the temperature detection means. Means, a metal core member having a thickness of 0.3 mm or less is used as a metal core member of the heating roll, and a thermal time constant of 0.8 sec or less is used as the temperature detecting means. It is configured to be used.

According to a second aspect of the present invention, in the heat fixing device according to the first aspect, the shape of the end of the metal core member is narrowed inward at both axial ends of the heating roll. Is a heat fixing device.

According to a third aspect of the present invention, in the heat fixing device according to the second aspect, a process of narrowing down to the inside around the entire circumference of a gear mounting groove for rotationally driving the heating roll is performed. This is a characteristic heat fixing device.

According to a fourth aspect of the present invention, in the heat fixing apparatus according to any one of the first to third aspects, the thickness of the release material layer of the heating roll is set to 25 μm or less on average. A heat fixing device is characterized in that:

According to a fifth aspect of the present invention, in the heat fixing device according to any one of the first to fourth aspects, the releasable material layer of the heating roll has a tubular shape made of a fluorine-based resin. A heat fixing device characterized by being formed by the coating of (1).

According to a sixth aspect of the present invention, in the heat fixing device according to the fifth aspect, the tubular coating made of a fluorine-based resin for forming the release material layer of the heating roll is heated. A heat fixing device characterized in that silicon carbide is blended in an amount of 10% by weight or more with an adhesive to be bonded to a metal core of a roll.

According to a seventh aspect of the present invention, in the heat fixing device according to any one of the fourth to sixth aspects, the adhesive layer for bonding a release material layer to a metal core of the heating roll is provided. A heat fixing device having a thickness set to 4 to 8 μm.

According to an eighth aspect of the present invention, in the heat fixing device according to any one of the fourth to seventh aspects, the lowermost layer of the release material layer of the heating roll has a resistance value of 10 ¹⁵ Ω or more. Wherein the insulating layer is provided in a range of 2.5 to 4 μm.

According to a ninth aspect of the present invention, in the heat fixing device according to any one of the fourth to eighth aspects, the heating source for heating the heating roll emits light energy, so that the heating roll is heated. A heating source for heating
In order to efficiently absorb the light energy emitted from the heating source and convert it into heat energy, the heat source has a spectral distribution on the inner wall of the heating roll, which has a wavelength peak of 1100 to 1200 nm. A heat fixing device, wherein an inner surface coating material having a rate of 5% or less is applied.

[0023] The invention described in claim 10 is the ninth invention.
3. The heat fixing device according to claim 1, wherein an application range of the inner surface coating material for efficiently absorbing the light energy is at least an image area of the heating roll.

The invention described in claim 11 is the ninth invention.
Or the thermal fixing device according to 10, wherein the coating thickness of the inner coating material for efficiently absorbing the light energy is 5
A heat fixing device, wherein the heat fixing device is set in a range of 15 μm to 15 μm.

The invention described in claim 12 is the first invention.
Wherein the material of the bearing member that rotatably supports the heating roll contains 30 wt% or more of graphite using a liquid crystal polymer as a main raw material.
A heat fixing device characterized in that a resin having a load deflection temperature of 240 ° C. or more in a state where 8 Mpa is applied is used as a material.

The invention described in claim 13 is the first invention.
3. The heat fixing device according to 2, wherein a bearing width of the bearing member that rotatably supports the heating roll is set to 5 mm or more on one side.

The invention described in claim 14 is the first invention.
14. The heat fixing device according to item 2 or 13, wherein a clearance between an outer diameter of a bearing portion of the heating roll and an inner diameter of a bearing member that rotatably supports the heating roll is set to 0.
A heat fixing device characterized by being set to 1 mm or more.

The invention described in claim 15 is the first invention.
The heat fixing device according to any one of 2 to 14, wherein the roundness of the bearing member and the inner diameter of the heating roll is 50 μm or less, and the sink of the sliding portion in the axial direction of the heating roll is 30 μm or less. This is a heat fixing device characterized by setting.

The invention described in claim 16 is the first invention.
16. The heat fixing device according to any one of 2 to 15, wherein an appropriate amount of silicone oil is applied to a bearing portion of the heating roll and a sliding portion of a bearing member that rotatably supports the heating roll. This is a heat fixing device.

The invention described in claim 17 is the first invention.
7. The heat fixing device according to 6, wherein the viscosity of the silicone oil is 1000 cs or more.

The invention described in claim 18 is the first invention.
3. The thermal fixing device according to claim 1, wherein the temperature detecting means includes a thermistor element, and the metal material on which the thermistor element is mounted has a radius of curvature of 10 μm or more at a corner on the heat-sensitive surface side. Is applied to the heat fixing device.

The invention described in claim 19 is the first invention.
20. The heat fixing device according to claim 18, wherein a release tape made of a thin film of a fluororesin is adhered to a surface of the temperature detecting means.

The invention described in claim 20 is the first invention.
9. The thickness of the release tape (including an adhesive) attached to the surface of the temperature detecting means in the heat fixing device according to item 9.
Is set to 50 μm or less.

The invention described in claim 21 is the first invention.
In the thermal fixing device described in the above item, a device provided with a thermistor element is used as the temperature detecting means, and the metal material on which the thermistor element is mounted has a plate thickness of 0.
A heat fixing device selected from the range of 07 to 0.15 mm.

According to a twenty-second aspect of the present invention, in the thermal fixing device according to the first aspect or any one of the seventeenth to twenty-first aspects, the temperature detecting means may have a solid angle of 3π or more within 30 mm nearby. A heat fixing device, which is surrounded by a heating roll and other members constituting the heat fixing device.

The invention described in claim 23 is the first invention.
In the thermal fixing device described in (1), the temperature detection by the temperature detection unit is performed by converting a resistance value of a temperature-dependent resistance element used as the temperature detection unit into a digital value by an A / D converter. A circuit for detecting a temperature by the temperature detecting means includes a temperature detecting means and a resistance circuit whose resistance value can be switched in a plurality of stages connected in series, and an A / D converter is connected to the temperature detecting means. A heat fixing device characterized by being connected in parallel.

The invention described in claim 24 is the second invention.
3. The thermal fixing device according to claim 3, wherein the resistance circuit capable of switching the resistance value in a plurality of stages switches the resistance value in accordance with a temperature range where temperature detection is required. is there.

The invention described in claim 25 is the first invention.
In the heat fixing device described in (1), a toner scraping member that contacts with a predetermined pressure is provided on the surface of the heating roll, and the toner scraping member is set upstream of the temperature detection unit in the rotation direction of the heating roll. The portion where the toner scraping member comes into contact with the heating roll has a linear shape parallel to the axial direction of the heating roll.

The invention described in claim 26 is the second invention.
5. The heat fixing device according to 5, wherein the pressure at which the toner scraping member contacts the heating roll is 1.1 to 2.0 gf.
/ Cm is set.

The invention described in claim 27 is the second invention.
27. In the heat fixing device described in 5 or 26, the portion where the toner scraping member contacts the heating roll has a radius of curvature of 0.1 m in a plane orthogonal to the axial direction of the heating roll.
A heat fixing device, wherein the heat fixing device is formed in an R shape of m or less.

The invention described in claim 28 is the second invention.
In the heat fixing device according to any one of Items 5 to 27, a portion where the toner scraping member contacts a heating roll includes:
A heat fixing device characterized by being formed in an R shape with a radius of curvature of 0.3 mm or more in a plane parallel to the axial direction of the heating roll.

The invention described in claim 29 is the second invention.
29. The heat fixing device according to any one of items 5 to 28, wherein a material of at least a portion of the toner scraping member that contacts the heating roll is a sintered body mainly containing PPS. It is.

The invention described in claim 30 is the second invention.
9. The thermal fixing device according to 9, wherein a breaking strength of at least a tip portion of the toner scraping member that contacts the heating roll is 0.8 kgf / cm or more.

The invention described in claim 31 is the second invention.
31. The heat fixing device according to any one of 5 to 30, wherein the image to be fixed by the heat fixing device is formed of a toner containing a magnetic component, and the toner is disposed on a circulating side of the toner scraping member in a heating roll rotation direction. A heat fixing device provided with a magnetic member for capturing toner scraped off by a scraping member.

According to the invention described in claim 32, there is provided a heating roll having a surface covered with a release material layer and having a heating source disposed therein, and a nip portion which is pressed against the heating roll and interposed therebetween. A pressure roll disposed so as to pass through a recording medium carrying a landing image, and a surface of which is covered with a release material layer, a temperature detection unit for detecting a surface temperature of the heating roll, and the temperature detection unit In the image forming apparatus using a heat fixing device having a temperature control means for controlling energization to a heating source based on the detection result, the metal core member of the heating roll has a thickness of 0.3 mm or less. And an image forming apparatus using a temperature detecting means having a thermal time constant of 0.8 sec or less.

[0046]

According to the first aspect of the present invention, since a metal core member having a thickness of 0.3 mm or less is used as the metal core member of the heating roll, the metal member is provided with an extremely thin metal core member. In addition, the surface of the heating roll can be heated to a predetermined temperature with a small amount of heat, energy can be saved, a warm-up time can be reduced, and the invention can be applied to an on-demand printer. Further, in the invention described in claim 1, since the temperature detecting means is configured to use one having a thermal time constant of 0.8 sec or less, as shown in FIG. The temperature can be immediately detected without a time delay and controlled to a predetermined temperature, the drift can be suppressed to a small value of about 4 ° C., the fixing temperature can be set low, and the accurate temperature can be set. Control is possible, and it is possible to prevent image defects from occurring. FIG. 7 is a graph showing a temperature change when a heating roll using a 0.2 mm-thick iron core is controlled to have a control temperature of 173 ° C. In addition, according to experiments performed by the present inventors, an effect was recognized when a temperature detecting means having a thermal time constant of 0.8 sec or less was used. Further, as the material of the metal core, other materials such as stainless steel may be used in addition to iron.

In addition, with the constitution as described in claims 2 and 3, sufficient strength can be maintained even when the heating roll is made thin.

Furthermore, the thickness of the release material layer of the heating roll is set to an average of 25 μm or less, or the release material layer is formed on the metal core of the heating roll. The thickness of the adhesive layer to be bonded is set to 4 to 8 μm, and
As in claim 6, silicon carbide is used as an adhesive for bonding a tubular coating made of a fluorine-based resin forming a release material layer of a heating roll to a metal core of the heating roll. By mixing the amount by weight or more, the heating time of the heating roll can be shortened, and the control temperature at the time of fixing can be reduced.

The releasable material layer of the heating roll is coated with a tube made of a fluorine-based resin to improve the releasability and eliminate image quality defects. A high-quality image with good image quality can be obtained.

According to the present invention, an insulating layer having a resistance value of 10 ¹⁵ Ω or more is provided in the lowermost layer of the releasable material layer of the heating roll in a range of 2.5 to 4 μm. It is possible to prevent the charge of the image from escaping to the metal core and disturbing the toner image.

Further, by constituting the present invention as described in claims 9 to 11, even when a heating source such as a halogen lamp is used,
Good thermal efficiency and shortens the heating time.

In addition, the driving torque of the heating roll can be reduced, and secondary troubles such as generation of abnormal noise in the bearing of the heating roll can be prevented.

Further, according to the eighteenth aspect, it is possible to prevent the heat-sensitive surface of the temperature detecting means from damaging the surface of the heating roll and thereby causing an image quality defect.

Further, according to claim 19,
It is possible to suppress the toner from adhering to the surface of the temperature detecting unit, and prevent the detection accuracy of the temperature detecting unit from being lowered.

In addition, with the configuration according to the twentieth to twenty-first aspects, the accuracy of temperature detection by the temperature detecting means can be improved.

According to a twenty-second aspect, by substantially sealing the periphery of the temperature detecting means, the air flow near the temperature detecting means can be stably reduced, and the temperature detecting means is cooled more than necessary. And the accuracy of detecting the temperature of the heating roll can be improved.

According to the structure of claim 23 or 24, highly accurate temperature detection can be performed in a wide temperature range.

Further, by providing the toner scraping member as in claims 25 to 31, the toner adhered to the heating roll can be prevented from re-adhering to the temperature detecting means, and the temperature due to the adhered toner can be prevented. It is possible to obtain a heat fixing device that can prevent deterioration in control performance and damage to the heating roll and can maintain stable temperature control and maintain image quality even during long-term use.

Further, by adjusting the shape and contact pressure of the toner scraping member, it is possible to prevent the toner scraping member itself from damaging the heating roll.

Further, by adopting the shape of claim 28,
The toner scraping member is subject to variations such as component tolerances,
Even when the surface of the heating roll collides with the surface of the heating roll, the toner scraping member itself can be prevented from damaging the heating roll.

Still further, by providing the magnetic member, even if the toner collected by the toner scraping member falls by any chance, the toner drops on the paper or the heating roll by the magnetic member. , Can be prevented from becoming defective.

Further, according to the present invention, it is possible to provide an image forming apparatus having the same function as that of the first aspect.

[0063]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 is a schematic configuration diagram showing an electrophotographic desk printer as an image forming apparatus to which a heat fixing device according to Embodiment 1 of the present invention is applied.

In FIG. 2, reference numeral 1 denotes a main body of a printer. Inside the main body 1 of the printer, an image processing section 2 for performing predetermined image processing on image information input from the outside, An image output unit 3 that outputs an image based on image information on which predetermined image processing has been performed by the image processing unit 2 is provided. The image processing unit 2 in the printer main body 1 reads image information sent from a host computer such as a personal computer (not shown), a communication line such as a telephone line or a LAN, or an image reading device (not shown). Image information or the like is input.

An ROS 4 (Rast 4) for performing image exposure based on image information subjected to predetermined image processing by the image processing unit 2 is provided to an image output unit 3 in the printer main body 1.
ROS 4 is disposed in the ROS 4, and the laser light LB according to the image information.
Image exposure is performed.

In the ROS 4, as shown in FIG. 2, a laser beam LB is emitted from a semiconductor laser (not shown) in accordance with the gradation data of the image information. The laser beam LB emitted from the semiconductor laser is deflected and scanned by the rotary polygon mirror 5, and is scanned on the photosensitive drum 8 as an electrostatic latent image carrier via the reflection mirrors 6 and 7.

As the photosensitive drum 8 on which the laser beam LB is scanned and exposed by the ROS 4, for example, a negatively charged photosensitive body using an organic photoconductive substance (OPC) is used. Reference numeral 8 is adapted to be rotationally driven at a predetermined speed along a direction indicated by an arrow by driving means (not shown). As shown in FIG. 2, the surface of the photosensitive drum 8 is uniformly charged in advance to a predetermined potential by a charging roll 9 as a charging unit, and then is scanned and exposed to laser light LB in accordance with image information. This forms an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 8 is transferred to a developing roll 11 of a developing device 10 as a developing unit.
To form a toner image.

The toner image formed on the photosensitive drum 8 is transferred to a recording paper 13 as a recording medium by a transfer roll 12 arranged so as to be in contact with the photosensitive drum 8.
The recording paper 13 to which the toner image has been transferred and which has been transferred onto the photosensitive drum is discharged by a separation charger 14 comprising a needle-shaped electrode, if necessary, and / or the rigidity of the recording paper 13. 8 is separated. An AC voltage or an AC voltage obtained by superimposing a DC voltage is applied to the separation charger 14 including the needle-shaped electrodes. The recording paper 13 is, as shown in FIG.
Sheets of a desired size are fed from a paper cassette 15 or 16 arranged at a lower portion of the inside of the paper cassette 15 along a sheet transport path 18 in a state where the sheets are separated one by one by a feed roll 17. The fed recording paper 13 is moved by the registration roll 19 to the surface of the photosensitive drum 8.
It is transported at a predetermined timing.

The printer body 1 includes a plurality of paper cassettes 15 and 16 as shown in FIG.
From these paper cassettes 15 and 16, recording papers 13 having different widths, lengths, and thicknesses can be fed. Also, from the paper cassettes 15 and 16, A4
It is possible to feed not only fixed sizes such as size and A3 size, but also recording media of different materials and sizes such as OHP sheets and postcards.

As described above, the recording paper 13 onto which the toner image has been transferred from the photosensitive drum 8 is separated from the rigidity of the recording paper 13 and / or, if necessary, the separated charging composed of needle-like electrodes. After the electricity is removed by the heater 14 and separated from the surface of the photosensitive drum 8, the transport chute 2
1 and is conveyed to the thermal fixing device 22. The recording sheet 13 separated from the surface of the photosensitive drum 8 is discharged after the toner image is fixed on the recording sheet 13 by heat and pressure by the heating roll 23 and the pressure roll 24 of the heat fixing device 22. The paper is discharged onto the paper discharge tray 26 provided on the upper part of the printer main body 1 by the paper roll 25, and the image forming process is completed.

After the toner image transfer step is completed, the residual toner is removed from the surface of the photosensitive drum 8 by a cleaning device 28 having a cleaner blade 27 as shown in FIG. It is prepared for the forming process.

In the printer constructed as described above, as shown in FIG. 2, the photosensitive drum 8 and the developing device 10 and the cleaning device 28 around the photosensitive drum 8 are provided with a process cartridge for improving maintenance. The process cartridge 30 is integrally unitized as a unit 30, and is detachably attached to the printer main body 1. The process cartridge 30 includes:
By opening the upper cover, part of which also serves as the discharge tray 26, it is possible to lift it up above the printer body 1, and it is detachably attached to the printer body 1. Further, the process cartridge 30
Is set so that the timing of deterioration of the photosensitive drum 8 and the timing of consumption of the developer in the developing device 10 are almost the same, and the photosensitive drum 8 is worn and deteriorated, When the developer in the toner cartridge 10 is consumed, the photosensitive drum 8 and the developing device 10 are replaced with a new one instead of replacing the photosensitive drum 8 and the developing device 10 with new ones. It is possible to improve maintainability by integrally attaching and detaching from the unit 1 and replacing it with a new one. Note that FIG.
Reference numeral 29 denotes the process cartridge 30 for the printer body 1
3 shows a shutter that covers the surface of the photoconductor drum 8 when the photoconductor drum 8 is detached from the photoconductor drum 8.

In the first embodiment, the heat fixing device includes a heating roll having a surface covered with a release material layer and a heating source disposed therein, and a nip between the heating roll and the heating roll. A pressure roll disposed so as to pass a recording medium carrying an unfixed image in the portion, the surface of which is coated with a release material layer, a temperature detection unit for detecting a surface temperature of the heating roll, Temperature control means for controlling the energization of the heating source based on the detection result of the temperature detection means. The heating roll is configured so that a metal core member having a thickness of 0.3 mm or less is used, and a temperature detecting means having a thermal time constant of 0.8 sec or less is used.

FIG. 3 shows a heat fixing device according to the first embodiment.

As shown in FIG. 3, the heat fixing device 22 includes a heating roll 23 and a pressure roll 24. The heating roll 23 and the pressure roll 24 are driven to rotate while being pressed against each other. Heating roll 23 and pressure roll 24
The recording paper 1 on which the toner image has been transferred to the nip portion 31 between
3, the toner image is fixed on the transfer paper by heat and pressure.

As shown in FIG. 4, the heating roll 23 includes a thin cylindrical iron core 32 having a thickness of 0.2 mm and a primer layer (thickness 6 μm) applied to the surface of the iron core 32. An adhesive layer) 33 and a release material layer 34 made of Teflon (trade name) tube having a thickness of 20 μm and coated on the surface of the primer layer 33. Inside the iron core bar 32, a heater 35 composed of a halogen lamp or the like as a heating source is provided.

As shown in FIG. 5, the heating roll 23 has metal core members 32 at both ends in the axial direction.
Is configured to perform a process (curling process) of narrowing the shape of the end portion inward. Further, the heating roll 23 is formed at one axial end thereof with a U-shaped groove 23a for mounting a gear (not shown) for driving the heating roll 23 to rotate.
A process (curling process) of narrowing the shape of the end portion of the metal core member 32 inward is also applied to the entire circumference of a.

The thickness of the release material layer 34 made of Teflon (trade name) tube is set to an average thickness of less than 25 μm. This is because when the thickness of the releasable material layer 34 becomes 25 μm or more on average, it is necessary to set the control temperature higher by 6 ° C. or more in order to obtain the necessary fixing strength by the experiments of the present inventors. This is because it has been found that the margin for temperature rise and the like is reduced accordingly.

Further, the releasable material layer 34 is
As the primer layer (adhesive layer) 33 to be adhered to the surface of No. 2, for example, a layer containing 10% by weight or more of silicon carbide is used, and the thickness of the primer layer 33 is 4 to 8 μm.
m. This is the primer layer (adhesive layer)
The present inventor has found that by using a material containing silicon carbide in an amount of 10% by weight or more, the thermal conductivity of the primer layer 33 can be improved and the fixability can be improved. It has been confirmed by these experiments. If the thickness of the primer layer 33 is less than 4 μm, the release material layer 34 cannot be bonded well to the surface of the iron core 32, while the thickness of the primer layer 33 is 8 μm It has been confirmed by the inventors of the present invention that the fixing property is deteriorated when the value exceeds.

Further, if necessary, an insulating layer (not shown) having a resistance value of 10 ¹⁵ Ω or more is formed on the lowermost layer of the release material layer 34 of the heating roll 23, that is, on the surface of the metal core member 32. Is provided in the range of 2.5 to 4 μm. Thus, the resistance value of 10 ¹⁵ Ω is applied to the surface of the metal core member 32.
By providing the insulating layer (not shown) in the range of 2.5 to 4 μm, it is possible to reliably prevent the charge from escaping and causing the image disorder.

Further, as shown in FIG. 4, on the inner wall of the heating roll 23, the light energy emitted by the halogen lamp 35 as a heating source is efficiently absorbed and converted into heat energy. An inner coating material 23b having a spectral reflectance of 5% or less is applied to a heating element having a spectral distribution of a heating source having a wavelength peak of 1100 to 1200 nm. This inner surface coating material 23b
For example, Serumo L1-90 of Tokyo Thermal Chemical Industry
0 Black 2 (trade name) is used. The coating range of the inner surface coating material 23b is set to at least the image area of the maximum size sheet to be fixed by the heating roll 23,
Preferably, it is set wider than the image area. The coating thickness of the inner surface coating material 23b is set in a range of 5 to 15 μm. This is because if the coating thickness of the inner coating material 23b is less than 5 μm, the effect of the inner coating material 23 cannot be sufficiently obtained, and if the coating thickness of the inner coating material 23b exceeds 15 μm, the thermal conductivity becomes lower. This is because it has been confirmed by the experiments of the present inventors that the toner content decreases by that much and the fixability decreases.

The heating roll 23 is rotatably supported at both ends by bearing members 60 as shown in FIG. These bearing members 6
0 is, for example, the material contains 30 wt% or more of graphite using a liquid crystal polymer as a main raw material, and 1.8M
It is formed of a resin having a deflection temperature under load of 240 ° C. or more when pa is applied. Therefore, even when the surface of the heating roll 23 is heated to about 240 ° C., it is possible to prevent the bearing member 60 from being deformed. In FIG. 6, the bearing member 60 is attached so as to receive the pressing force from the pressing roll 24 in the direction of the arrow, and the width W of the portion 61 receiving the pressing force from the pressing roll 24 is one side. And W is set to 5 mm or more. This makes it possible for the bearing member 60 to sufficiently support the pressing force of the pressure roll 24. Further, the bearing member 60 is connected to the heating roll 23.
The clearance between the outer diameter of the bearing portion and the inner diameter D of the bearing member 60 is set to 0.1 mm or more at normal temperature. As described above, by setting the clearance between the outer diameter of the bearing portion of the heating roll 23 and the inner diameter D of the bearing member 60 to be 0.1 mm or more at room temperature, even when the room temperature is lowered, the clearance between the two is maintained. It has been confirmed by experiments of the present inventors that a sufficient clearance can be ensured and a drive torque can be prevented from increasing. The circularity of the inner diameter of the bearing member 60 is 50 μm or less, and the heating roll 2
The sink amount of the sliding portion in the axial direction of No. 3 is set to 30 μm or less. Here, the sink amount of the sliding portion in the axial direction of the heating roll 23 is, as shown in FIG. 6 (b), when the bearing member 60 is manufactured by molding with a synthetic resin or the like. In some cases, the resin forming the inner surface shrinks to form a concave portion, which means the depth of the concave portion. By setting the roundness of the inner diameter of the bearing member 60 to 50 μm or less and the sink of the sliding portion in the axial direction of the heating roll 23 to 30 μm or less, the driving torque of the heating roll 23 is reduced. Can be suppressed to a sufficiently low value.

A suitable amount of silicone oil is applied to the bearing of the heating roll 23 and the sliding portion of the bearing member 60 which rotatably supports the heating roll 23, if necessary. For example, a viscosity of 1000 cs or more is used. By doing so, the contact resistance between the bearing portion of the heating roll 23 and the sliding portion of the bearing member 60 that rotatably supports the heating roll 23 can be significantly reduced, and the driving torque of the heating roll 23 can be reduced. It can be a small value.

The pressure roll 24 is formed to have substantially the same outer diameter as the heating roll 23, and has a cylindrical metal core 36, and a urethane having a thick coating on the surface of the metal core 36. An elastic body layer 37 made of a sponge made of, for example, and a release material layer 38 made of a Teflon (trade name) tube having a thickness of about 20 μm coated on the surface of the elastic body layer 37. As shown in FIG. 3, the pressure roll 24 is provided with rotating shafts 3 provided at both ends of a metal core 36 thereof.
The pressure roller 9 is disposed so as to be pressed against the surface of the heating roll 23 with a predetermined pressure by a pressure spring (not shown) via a support member 40 that supports the shaft 9.

Further, on the surface of the heating roll 23,
As shown in FIG. 3, a temperature sensor 41 as a temperature detecting means for detecting the surface temperature of the heating roll 23 is disposed so as to be in contact with the heating roll 23. As shown in FIG. 7, the temperature sensor 41 has a thermal time constant of 0.7 sec. According to experiments by the present inventors, it has been confirmed that the temperature sensor 41 can be used with a small time delay of temperature detection as long as the thermal time constant is 0.8 sec. The temperature sensor 41 is disposed, for example, at the center of the heating roll 23 in the axial direction, or at a position slightly closer to one end than the center. In addition, heating roll 2
A guide member 43 for guiding the recording paper 13, which has been subjected to the fixing process at the nip portion 31 between the heating roll 23 and the pressure roll 24, to an exit roll 42 is provided on the upper part of the recording paper 13.
Further, peeling claws 44 for peeling the recording paper 13 from the surface of the heating roll 23 are provided on both ends of the guide member 43 in the longitudinal direction.

As shown in FIG. 8, the temperature sensor 41 as the temperature detecting means has a thermistor element 65 made of a semiconductor whose resistance changes according to the temperature. The thermistor element 65 is mounted via thin lead wires 66 on two thin leaf springs 67 made of an elastic metal material. Metal leaf spring 67 mounting the thermistor element 65
As shown in FIG. 8C, a corner 6 on the heat-sensitive surface side
8 is subjected to an R process with a radius of curvature of 10 μm or more over the length in contact with the surface of the heating roll 23. Further, on the surface of the temperature sensor 41, a release tape 69 made of a thin film of a fluororesin such as Teflon (registered trademark) is adhered so as to be wound around the entire circumference. The thickness (including the adhesive) of the release tape 69 is set to, for example, 50 μm or less. If the thickness (including the adhesive) of the release tape 69 exceeds 50 μm, the thermal time constant decreases, which is not preferable. In FIG. 8, FIG. 8B shows a surface in contact with the heating roll 23.

As shown in FIG. 8D, the leaf spring 67 as a metal material on which the thermistor element 65 is mounted has a thickness of 0.07 mm at a thin place and a thickness of 0.07 mm at a thick place. Is set to 0.15 mm to prevent the leaf spring 67 from strongly hitting the heating roll 23 and prevent the leaf spring 67 from storing heat.

Further, as shown in FIG. 1, the temperature sensor 41 has a solid angle of 3 mm within 30 mm in the vicinity thereof.
π or more is surrounded by the heating roll and other members constituting the heat fixing device, and the air flow around the heating roll 23 and in the axial direction is detected by the temperature sensor 41.
Is prevented from hitting. In addition, it has been confirmed by experiments by the present inventors that the fluctuation of the temperature detected by the temperature sensor 41 can be sufficiently suppressed by covering the solid angle of 3π or more within 30 mm in the vicinity of the temperature sensor 41. .

FIG. 9 is a block diagram showing a control circuit for performing a printing operation of a desktop printer having the above-described heat fixing device and controlling the temperature of the heat fixing device.

In FIG. 9, reference numeral 50 denotes a CPU as control means for controlling the printing operation of the desktop printer and temperature control of the thermal fixing device; 51, a ROM storing a program for the control operation executed by the CPU 50; CP
RAM for storing parameters and the like used for control operations and the like executed by U50, 41 is a temperature sensor for detecting the surface temperature of the heating roll 23 of the heat fixing device 22, and 35 is a heater for heating the heating roll of the heat fixing device 22 , 53 control the energization of the heater 35 based on the detection result of the temperature sensor 41, thereby controlling the surface temperature of the heating roll 23 as an SRR (Solid State).
(Relay).

Further, as shown in FIG. 9, the detection data of the temperature sensor 41 is transmitted to a C
The data is input to the PU 50. As shown in FIG. 10, the temperature detection circuit 70 includes a temperature-dependent thermistor element 65 used as the temperature sensor 41.
Is converted into a digital value by the A / D converter 71 and detected. The temperature detection circuit 70 is configured by connecting a temperature sensor 41 and a resistance circuit 72 whose resistance value can be switched in a plurality of stages in series, and connecting an A / D converter 71 to the temperature sensor 41 in parallel. . In addition, the resistance circuit 72 in which the resistance value can be switched in a plurality of stages connects the resistance R1 and the resistance R2 in parallel so that the resistance value can be switched corresponding to a temperature range in which temperature detection is required. A switch SW is connected in series with the resistor R2, and the switch SW is turned on.
/ Off switches the resistance value between two levels,
The heated heating roll 23 detected by the temperature sensor 41
And the temperature (room temperature) when the heating roll 23 is not heated can be accurately detected. As the resistance of the resistance circuit 72 is closer to the resistance of the temperature sensor 41, the voltage detected by the A / D converter 71 appears as a large change, and the detectable resolution is higher.

Further, in this embodiment, as shown in FIG. 1, a toner scraping member 80 (hereinafter, referred to as "scraper") is provided on the surface of the heating roll 23 so as to come into contact with a predetermined pressure. The scraper 80 is set upstream of the temperature sensor 41 in the rotation direction of the heating roll 23, and the scraper 80 is
Is configured to be a straight line parallel to the axial direction of the heating roll 23.

As shown in FIG. 11, the scraper 80 has a substantially L-shaped side surface and is rotatably attached to both ends of a base end portion 81 thereof. It is composed of a sintered body containing PPS (polyphenylene sulfide) as a main component. The tip 82 of the scraper 80 has a breaking strength set to 0.8 kgf / cm or more. Even when the tip 82 is used for the heating roll 23 having a thin surface layer, it does not break for a long period of time. Usefulness has been confirmed by the present inventors.

Further, as shown in FIG. 11, the scraper 80 is pressed against the surface of the heating roll 23 by a spring or the like (not shown).
It is set to 1 to 2.0 gf / cm. This is shown in FIG.
As shown in FIG. 2, the pressing force of the scraper 80 is 1.1 to
Experiments by the present inventors have confirmed that the degree of flaws generated on the surface of the heating roll 23 can be suppressed to 2 or less, which is not a problem as an image defect, by setting to 2.0 gf / cm. . Still further, as shown in FIG.
3 is in contact with the heating roller 23
The radius of curvature is 0.1 mm in a plane perpendicular to the axial direction of
It is formed in the following R shape. In the scraper 80, a portion 82b that comes into contact with the heating roll 23 is formed in an R shape having a radius of curvature of 0.3 mm or more in a plane parallel to the axial direction of the heating roll 23.

Further, in this embodiment, as shown in FIG. 1, the image to be fixed by the heat fixing device 22 is composed of toner containing a magnetic component, and is located on the circulating side of the scraper 80 in the direction of rotation of the heating roll. A magnet 90 as a magnetic member for capturing the toner scraped by the scraper
Is installed. The magnet 90 is formed wider than the width of the distal end portion 82 of the scraper 80, and is fixed to the distal end of the support member 91 by means such as adhesion. You.

[0097]

As described above, according to the present invention,
In the invention described in claim 1, since the thickness of the metal core member of the heating roll is configured to be 0.3 mm or less, the metal member is provided with an extremely thin metal core member.
The surface of the heating roll can be heated to a predetermined temperature with a small amount of heat, energy can be saved, a warm-up time can be shortened, and the invention can be applied to an on-demand printer. Also, in the invention described in claim 1, since the temperature detecting means is configured to use one having a thermal time constant of 0.8 sec or less,
The surface temperature of the heating roll can be immediately detected without any time delay and controlled to a predetermined temperature.The fixing temperature can be set low, and accurate temperature control is possible, and image defects are reduced. This can be prevented from occurring.

[0098] In addition, by configuring as in claims 2 and 3, sufficient strength can be maintained even when the heating roll is made thin.

Further, the thickness of the releasable material layer of the heating roll is set to 25 μm or less on average, or the releasable material layer is formed on the metal core of the heating roll. The thickness of the adhesive layer to be bonded is set to 4 to 8 μm, and
As in claim 6, silicon carbide is used as an adhesive for bonding a tubular coating made of a fluorine-based resin forming a release material layer of a heating roll to a metal core of the heating roll. By mixing the amount by weight or more, the heating time of the heating roll can be shortened, and the control temperature at the time of fixing can be reduced.

In addition, the releasable material layer of the heating roll is coated with a tube made of a fluororesin as a material, so that the releasability is improved and there is no image quality defect. A high-quality image with good image quality can be obtained.

Further, according to the present invention, by providing an insulating layer having a resistance value of 10 ¹⁵ Ω or more in the range of 2.5 to 4 μm as the lowermost layer of the releasing material layer of the heating roll, It is possible to prevent the charge of the image from escaping to the metal core and disturbing the toner image.

Further, with the configuration according to the ninth to eleventh aspects, even when a heating source such as a halogen lamp is used,
Good thermal efficiency and shortens the heating time.

Further, the driving torque of the heating roll can be reduced, and secondary obstacles such as generation of abnormal noise in the bearing of the heating roll can be prevented.

According to the eighteenth aspect, it is possible to prevent the heat-sensitive surface of the temperature detecting means from damaging the surface of the heating roll, thereby preventing image quality defects.

Further, according to claim 19,
It is possible to suppress the toner from adhering to the surface of the temperature detecting unit, and prevent the detection accuracy of the temperature detecting unit from being lowered.

Further, with the configuration as described in claims 20 to 21, the accuracy of temperature detection by the temperature detecting means can be improved.

[0107] By substantially sealing the periphery of the temperature detecting means, the air flow near the temperature detecting means can be stably reduced, and the temperature detecting means is cooled more than necessary. And the accuracy of detecting the temperature of the heating roll can be improved.

According to the structure of the twenty-third or twenty-fourth aspect, highly accurate temperature detection can be performed in a wide temperature range.

Further, by providing the toner scraping member as in claims 25 to 31, the toner adhered to the heating roll can be prevented from re-adhering to the temperature detecting means, and the temperature due to the adhered toner can be prevented. It is possible to obtain a heat fixing device that can prevent deterioration in control performance and damage to the heating roll and can maintain stable temperature control and maintain image quality even during long-term use.

Further, by adjusting the shape and contact pressure of the toner scraping member, it is possible to prevent the toner scraping member itself from damaging the heating roll.

Further, by adopting the shape of claim 28,
The toner scraping member is subject to variations such as component tolerances,
Even when the surface of the heating roll collides with the surface of the heating roll, the toner scraping member itself can be prevented from damaging the heating roll.

Further, by providing the magnetic member, even if the toner collected by the toner scraping member falls by any chance, the toner is dropped on the paper or the heating roll by the magnetic member. , Can be prevented from becoming defective.

Further, according to the present invention, it is possible to provide an image forming apparatus having the same function as that of the first aspect.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a heat fixing device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a printer as an image forming apparatus using the heat fixing device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a heat fixing device according to Embodiment 1 of the present invention.

FIG. 4 is a cross-sectional view showing a heating roll and a pressure roll of the heat fixing device according to Embodiment 1 of the present invention.

FIG. 5 is a perspective view showing a heating roll.

FIG. 6 is a perspective view showing a bearing member.

FIG. 7 is a graph showing experimental results.

FIG. 8 is a configuration diagram showing a temperature sensor.

FIG. 9 is a block diagram showing a control circuit.

FIG. 10 is a circuit diagram showing a temperature detection circuit.

FIG. 11 is a configuration diagram showing a scraper.

FIG. 12 is a graph showing experimental results.

FIG. 13 is a graph showing experimental results.

[Description of sign]

13: recording paper, 22: heat fixing device, 23: heating roll, 24: pressure roll, 32: metal core, 35: heating source, 41: temperature sensor.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16C 13/00 F16C 13/00 E G05D 23/24 G05D 23/24 G (72) Inventor Hideo Oshida Saitama 3-7-1, Fuchu, Iwatsuki City Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Shinichiro Oshita 3-7-1, Funai, Iwatsuki City, Saitama Prefecture Fuji Xerox Co., Ltd. Iwatsuki Office F-term (reference) 2H033 AA18 AA30 BA31 BA42 BA50 BA58 BB04 BB13 BB18 BB34 BB36 BB37 3J103 AA02 AA15 AA32. GG30 KK05 NN03

Claims (32)

[Claims] 1. A heating roll having a surface covered with a release material layer and having a heating source disposed therein, and a recording medium pressed against the heating roll and carrying an unfixed image in a nip therebetween. A pressure roll disposed so as to pass therethrough, the surface of which is coated with a release material layer, a temperature detection means for detecting a surface temperature of the heating roll, and a heating source based on a detection result of the temperature detection means. A temperature control means for controlling power supply to the heat roller, wherein a metal core member of the heating roll has a thickness of 0.3 m.
m, and a thermal fixing device having a thermal time constant of 0.8 sec or less as the temperature detecting means. 2. The heat fixing device according to claim 1, wherein the shape of the end of the metal core member is narrowed inward at both ends in the axial direction of the heating roll. Heat fixing device. 3. The heat fixing device according to claim 2, wherein a process of narrowing inward is performed on the entire circumference of a gear mounting groove for rotationally driving the heating roll. 4. The heat fixing device according to claim 1, wherein the thickness of the release material layer of the heating roll is 25 μm on average.
m, which is set to m or less. 5. The heat fixing device according to claim 1, wherein the releasable material layer of the heating roll is formed by a tubular coating made of a fluorine-based resin. A heat fixing device. 6. The heat fixing device according to claim 5, wherein a tube-shaped coating made of a fluorine-based resin forming a release material layer of the heating roll is bonded to a metal core of the heating roll. A heat fixing device characterized in that silicon carbide is blended in an amount of 10% by weight or more with an adhesive to be formed. 7. The heat fixing device according to claim 4, wherein the thickness of the adhesive layer for bonding the release material layer to the metal core of the heating roll is set to 4 to 8 μm. A heat fixing device characterized by setting. 8. The heat fixing device according to claim 4, wherein the lowermost layer of the release material layer of the heating roll has a resistance value of one.
A heat fixing device, wherein an insulating layer of 0 ¹⁵ Ω or more is provided in a range of 2.5 to 4 μm. 9. The heat fixing device according to claim 4, wherein the heating source for heating the heating roll is a heating source for heating the heating roll by emitting light energy. In order to efficiently absorb the light energy emitted by the heating source and convert the energy into heat energy, the heat source has a spectral distribution on the inner wall of the heating roll, which has a wavelength peak of 1100 to 1200 nm. A heat fixing device, wherein an inner surface coating material having a reflectance of 5% or less is applied. 10. The heat fixing device according to claim 9, wherein an application range of the inner surface coating material for efficiently absorbing the light energy is at least an image area of the heating roll. apparatus. 11. The heat fixing device according to claim 9, wherein a coating thickness of the inner surface coating material for efficiently absorbing the light energy is set in a range of 5 to 15 μm. Heat fixing device. 12. The heat fixing device according to claim 1, wherein a material of a bearing member rotatably supporting the heating roll is made of a liquid crystal polymer as a main raw material and 30 watts of graphite.
A heat fixing device comprising a resin having a load deflection temperature of 240 ° C. or higher in a state where 1.8 Mpa is applied, wherein the thermal fixing device contains t% or more. 13. The heat fixing device according to claim 12, wherein a receiving width of a bearing member that rotatably supports the heating roll is set to 5 mm or more on one side. 14. The heat fixing device according to claim 12, wherein a clearance between an outer diameter of a bearing portion of the heating roll and an inner diameter of a bearing member that rotatably supports the heating roll is set to 0 at room temperature. A heat fixing device characterized by being set to 1 mm or more. 15. The heat fixing device according to claim 12, wherein a roundness of a bearing member and an inner diameter of the heating roll is 50 μm.
The heat fixing device according to claim 1, wherein an amount of sink of the sliding portion in the axial direction of the heating roll is set to 30 μm or less. 16. The heat fixing device according to claim 12, wherein an appropriate amount of silicone oil is applied to a bearing portion of the heating roll and a sliding portion of a bearing member that rotatably supports the heating roll. A heat fixing device characterized by being applied. 17. The heat fixing device according to claim 16, wherein the viscosity of the silicone oil is 1000 cs or more. 18. The heat fixing device according to claim 1, wherein the temperature detecting means includes a thermistor element, and the metal material on which the thermistor element is mounted is provided at a corner on the heat-sensitive surface side. , A radius of curvature of 10 μm or more
A heat fixing device that has been subjected to processing. 19. The heat fixing device according to claim 1, wherein a release tape made of a thin film of a fluororesin is adhered to a surface of the temperature detecting means. . 20. The heat fixing device according to claim 19, wherein the thickness (including an adhesive) of the release tape adhered to the surface of the temperature detecting means is 50 μm or less. Heat fixing device. 21. The heat fixing device according to claim 1, wherein the temperature detecting means includes a thermistor element, and the metal material on which the thermistor element is mounted has a thickness of 0.07. A heat fixing device selected from the range of 0.15 mm to 0.15 mm. 22. The heat fixing device according to claim 1, wherein the temperature detecting unit is located within 30 mm of the vicinity thereof.
A heat fixing device, wherein a solid angle of 3π or more is surrounded by a heating roll and other members constituting the heat fixing device. 23. The thermal fixing device according to claim 1, wherein in the temperature detection by the temperature detection unit, a resistance value of a temperature-dependent resistance element used as the temperature detection unit is digitally converted by an A / D converter. A circuit for detecting the temperature by the temperature detecting means is connected in series with a temperature detecting means and a resistance circuit whose resistance value can be switched in a plurality of stages. A thermal fixing device comprising an A / D converter connected in parallel to a detecting means. 24. The thermal fixing device according to claim 23, wherein the resistance circuit capable of switching the resistance value in a plurality of stages has a configuration in which the resistance value is switched corresponding to a temperature range where temperature detection is required. Characteristic heat fixing device. 25. The heat fixing device according to claim 1, wherein a toner scraping member that contacts with a predetermined pressure is provided on a surface of the heating roll, and the toner scraping member is heated more than a temperature detecting unit. A heat fixing device, which is set on the upstream side in the rotation direction of the roll, wherein a portion where the toner scraping member contacts the heating roll is a linear shape parallel to the axial direction of the heating roll. 26. The heat fixing device according to claim 25, wherein a pressure at which the toner scraping member contacts the heating roll is set to 1.1 to 2.0 gf / cm. Fixing device. 27. The heat fixing device according to claim 25, wherein a portion where the toner scraping member contacts the heating roll has a radius of curvature of 0. 0 in a plane orthogonal to the axial direction of the heating roll. A heat fixing device formed in an R shape of 1 mm or less. 28. The heat fixing device according to claim 25, wherein a portion of the toner scraping member that contacts the heating roll has a radius of curvature in a plane parallel to an axial direction of the heating roll. Is formed in an R shape of 0.3 mm or more. 29. The heat fixing device according to claim 25, wherein a material of at least a portion of the toner scraping member that contacts the heating roll is a sintered body containing PPS as a main component. A heat fixing device. 30. The thermal fixing device according to claim 29, wherein a breaking strength of at least a tip portion of the toner scraping member that contacts the heating roll is 0.8 kgf / cm or more. apparatus. 31. The heat fixing device according to claim 25, wherein an image to be fixed by the heat fixing device is made of toner containing a magnetic component, and the toner scraping member is rotated by a heating roll. A heat fixing device, wherein a magnetic member for capturing the toner scraped by the toner scraping member is provided on the direction circulating side. 32. A heating roll having a surface covered with a release material layer and having a heating source disposed therein, and a recording medium pressed against the heating roll and carrying an unfixed image in a nip therebetween. A pressure roll disposed so as to pass therethrough, the surface of which is covered with a release material layer, a temperature detection unit for detecting the surface temperature of the heating roll, and a heating source based on a detection result of the temperature detection unit. An image forming apparatus using a heat fixing device having a temperature control means for controlling current supply to the heating roll, wherein a metal core member of the heating roll has a thickness of 0.3 m.
m and a thermal time constant of 0.8 sec or less is used as the temperature detecting means.