JPH0916003A - Fixing device - Google Patents

Abstract

PURPOSE: To provide a fixing device capable of realizing the miniaturization and the energy-saving of the device and also coping with color copying as to fixing device provided with a heating roller heating and fixing a toner image while coming in contact with and moving a recording medium where the toner image is formed, and a fixed heating element which does not come in contact with the recording medium at least on the upstream side of the heating roller. CONSTITUTION: In this device, the image formed with developer on the recording medium 9 is heated and fixed; and the device is equipped with a self-heating type heating and moving means 21 coming in contact with the surface of the medium 9, where the image of the developer 8 is formed, and moving the medium 9, and at least one fixed heating element 26 arranged in a non-contact state with the moving medium 9 at least on the upstream side out of the upstream side and the downstream side in the moving direction of the medium 9 with respect to the moving means 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an image forming apparatus such as an electrophotographic printer, in particular, heat is generated to fix the toner image while contacting and moving the recording medium on which the toner image is formed. The present invention relates to a fixing device having a rotating body and a fixed heating element that is not in contact with a recording medium and is provided at least on the upstream side of the rotating body.

In recent years, with the development of office automation, plain paper can be used, low noise, high speed and high quality printing can be obtained, and character image information output having the advantages of easy colorization is provided. Demand for equipment is increasing. Therefore, an electrophotographic printer or an electrostatic printer that forms an electrostatic latent image on a photosensitive drum and develops it with a developer is provided, and is used in a computer terminal device, a copying machine, a facsimile device, and the like.

In such a printer, downsizing of the apparatus and improvement of handleability which does not require a dedicated maintenance staff are desired. Among them, the fixing unit is downsized and consumes less energy. It has been demanded. In addition, the printer uses multicolor toner (Yellow Y, Magenta M, Cyan C, Black B
Colorization using K) is progressing, and a more advanced fixing state (melting degree of toner) is required for producing a desired color as compared with a conventional monochrome machine using only a single color toner.

Conventionally, the fixing device is composed of a heat fixing roller having a built-in heat source and a pressure roller (in some cases, the pressure roller also has the heat source) in pressure contact with the heat fixing roller. The recording medium having the unfixed toner image is passed between the heat fixing roller and the pressure roller to melt and fuse the toner on the recording medium.

As the heat fixing roller, a rubber roller in which a rubber having heat resistance and oil resistance is lined on a cylindrical raw tube which is usually made of aluminum is used, and the raw tube is formed by a heat source provided at the center of the raw tube. The rubber is being heated through.

However, since 50% or more of the electric power used by the printer is used by the fixing device, due to the recent environmental problems,
Energy saving is also required for these devices. Further, it takes time to raise the temperature of the heat fixing roller, and the warm-up time of the apparatus is long. Therefore, a method capable of shortening the warm-up time and saving energy is desired.

[0007]

2. Description of the Related Art FIG. 7 illustrates an internal side view of a multicolor electrophotographic printing apparatus. As shown in the drawing, the electrostatic latent images of the brush charger 2, the laser exposure device 3, and the photosensitive drum 1 are arranged around the photosensitive drum 1 rotating in the direction of the arrow in each color (yellow: Y,
Magenta: M, Cyan: C, Black: BK) toner 8a
The four developing devices 4a to 4d for developing by the above, the intermediate transfer device 5 provided with the intermediate transfer belt 50, the discharging lamp 6 and the cleaner 7 are arranged.

The developing devices 4a-4d are provided with toners 8a of different colors.
Due to a separation / contact mechanism (not shown), only one of the four is in contact with the photosensitive drum 1 during development, and the other three are separated.

The intermediate transfer device 5 includes a transfer roller 10 for transferring the toner image from the intermediate belt 50 to a printing paper (hereinafter referred to as paper) 9a, and a cleaner 1 for cleaning the toner 8a after the transfer.
1, a fixing device 12 that fixes the toner 8a on the paper 9a, and a conveyor belt 13 that conveys the paper 9a from the transfer roller 10 to the fixing device 12
Is arranged.

Therefore, the surface of the photosensitive drum 1 (when an organic photosensitive member is used) is uniformly negatively charged (for example, about -700 V) by the brush charger 2. Next, when the laser exposure device 3 irradiates the surface of the photosensitive drum 1 with light in accordance with a predetermined printing pattern, the charge of the exposed portion is reduced and an electrostatic latent image is formed.

When the electrostatic latent image passes through the developing device 4a for the first color, the negatively charged toner 8a adheres to the latent image area to form a toner image. Then, a voltage (for example, about 2 KV) having a polarity opposite to that of the toner 8a is applied to the intermediate transfer belt 50 of the intermediate transfer device 5 by the transfer roller 10, and the first color toner image attached to the photosensitive drum 1 comes into contact with the intermediate transfer belt 50. Transferred onto the intermediate transfer belt 50. The intermediate transfer device 5 rotates once around the intermediate transfer belt 50 to prepare for the next intermediate transfer of the second color.

The toner 8a remaining on the photosensitive drum 1 is completely discharged by the discharging lamp 6 and cleaned by the cleaner 7. Thus, the second to fourth colors are sequentially positioned at a timing, exposure, development and transfer are performed, and toner images of four colors are transferred onto the intermediate transfer belt 50 in an overlapping manner.

On the other hand, the paper 9a is conveyed to the position where it comes into contact with the toner images transferred onto the intermediate transfer belt 50 one by one in the arrow direction. The transfer roller 10 gives a positive charge to the paper 9a, and the toner image on the intermediate transfer belt 50 is attracted and transferred by the positive charge of the paper 9a.

After the toner images of four colors are transferred to the intermediate transfer device 5, the residual toner 8a on the photosensitive drum 1 is discharged and cleaned in the same manner as described above, and the intermediate transfer belt 50 is cleaned by the cleaner 11 to remove the residual toner. Then, they are returned to their initial states.

The paper 9a on which the four color toner images have been transferred is fixed by the fixing device 12 and sent to a stacker (not shown). In the above example, the case of the negative charging process has been described, but the same process applies to the positive charging.

The structure of the fixing device 12 will be described with reference to FIG. As shown in the figure, the fixing device 12 includes a heater H.
A heating roller 14 having a built-in (for example, a 1 kW halogen lamp), and a pressure roller 1 which is pressed against the heating roller 14 to rotate.
5, temperature sensor S composed of thermistor or thermocouple
t, the separation claw 16 for peeling the paper 9a from the heating roller 14, the paper guides 17a, 17b, etc. (the coating device for applying oil to the heating roller 14 and the cleaner for cleaning the toner 8a adhering to the heating roller 14 are not shown). It is configured.

The heating roller 14 and the pressure roller 15 are made of an aluminum material tube 140, and the surface of which is lined with rubber 141 (for example, silicone rubber) having heat resistance and oil resistance. The heater H is connected to the heater control circuit 19, and the temperature sensor St is connected to the temperature control circuit 20.

With such a configuration, the temperature control circuit 20 controls the heater control circuit 19 based on the temperature detection signal of the temperature sensor S to apply an AC voltage from the power source P to the heater H to heat the heating roller 14. The temperature sensor
After detecting the temperature in St and reaching a predetermined temperature, the surface temperature is controlled to be constant. The aluminum tube 140 is heated by the energization of the heater H, and this heat is conducted to the rubber 141 to raise the surface temperature of the heating roller 14.

Therefore, the paper on which the four color toner images have been transferred
9a is conveyed in the direction of the arrow and passes between the heating roller 14 and the pressure roller 15. At this time, the toner 8a on the paper 9a is
It is melted and pressed by the heat and pressure of the heating roller 14 and the pressure roller 15, and is solidified and fixed by the temperature drop after passing.

Since the heating roller 14 is rubber-lined, the surface of the toner image after fixing becomes smooth, and an image having a wide color reproduction range with good brightness and saturation can be obtained.

[0021]

According to the above-mentioned conventional method, the heating roller has a built-in heater and is lined with a heat-resistant and oil-resistant rubber on the aluminum material tube, and the heater is energized. The aluminum tube is heated, and this heat is conducted to the rubber to heat the paper inserted between the pressure roller and the paper and the toner on the paper.

Therefore, it takes a certain amount of time to raise the temperature of the aluminum raw tube and the rubber to a certain temperature according to their heat capacities, and the time until the surface temperature of the heating roller reaches the fixable temperature (warm-up time). ) Takes a long time (it takes about 5 minutes).

Further, the electric power used in the fixing device reaches 50% or more of the electric power used in the entire printer. Due to recent environmental destruction problems and the like, energy saving has been required for electronic devices, and a method for reducing the power consumption of a fixing device is desired.

Further, in the case of color printing as compared with monochrome printing, a fixing state for good color reproduction can be realized,
Moreover, energy saving is a major issue. At the same time as reducing the fixing energy, it is required to reduce the warm-up time of the fixing device and to downsize the fixing device itself in order to cope with the downsizing of the printer.

Various methods (Watanabe et al .: Journal of the Electrophotographic Society, 31, 156 (1992)) are being studied for energy saving and the like. In the conventional heating roller method, the SURF method in which a heat source is brought into direct contact with a recording medium through a film is used in addition to the thinning of the aluminum tube, in addition to shortening the rising time and saving energy. However, due to the fact that there is only one heat-generating portion and the fixing device is complicated, its application is limited to a device that uses a narrow sheet at a low speed. There is a problem.

It is an object of the present invention to provide a fixing device which can reduce the size of the device and save energy, and can cope with colorization.

[0027]

FIG. 1 is a diagram illustrating the principle of the present invention. In the figure, 8 is a developer, 9 is a recording medium, 21 is a heat generation moving means for causing the recording medium 9 to move in contact with the surface of the recording medium 9 on which the image is formed, and 26 is a heat generation movement. The recording medium 9 that moves at least upstream of the upstream and downstream sides of the means 21 in the moving direction of the recording medium 9
At least one fixed heating element arranged in a non-contact manner with the.

An image formed by the developer 8 on the recording medium 9 is heated and fixed by the fixed heating element 26 and the heating movement means 21. Hereinafter, means corresponding to claims 2 and 3 will be described.

According to a second aspect, in the first aspect, the fixed heating element 26 arranged on the upstream side in the moving direction of the recording medium 9 with respect to the heat moving means 21 has a distance from the recording medium 9 to that of the recording medium 9. The fixed heating element 26, which is arranged so as to narrow as it approaches the fixed heating element 26 from the upstream side in the moving direction, and which is arranged on the downstream side in the moving direction of the recording medium 9 with respect to the heat generation moving means 21,
The recording medium 9 is arranged so that the distance between the recording medium 9 and the recording medium 9 expands toward the downstream side in the moving direction of the recording medium 9 as the distance from the fixed heating element 26 increases.

According to a third aspect of the present invention, the divergence angle of the fixed heating element 26 arranged on the downstream side in the moving direction of the recording medium 9 with respect to the heat generating and moving means 21 is recorded in the heat generating and moving means 21. The configuration is set to be larger than the narrowing angle of the fixed heating element 26 arranged on the upstream side in the moving direction of the medium 9.

[0031]

As shown in FIG. 1, the recording medium 9 on which the image of the developer 8 is formed and is moved is heated by the fixed heating element 26 (preheating on the upstream side of the rotating body 21 and post-heating on the downstream side) to generate heat. By heating and fixing by the moving means 21, the developer 8 on the recording medium 9 is heated for a longer time, and fixing can be performed even if the temperatures of the fixed heating element 26 and the heating and moving means 21 are set low. Therefore, the time to rise to the set temperature,
That is, the warm-up time is shortened, power consumption is reduced, and energy saving is achieved. In addition, a fixing state can be obtained which improves color reproduction in the case of color.

The operation corresponding to claims 2 and 3 will be described below. In the second aspect, the distance between the fixed heating element 26 and the recording medium 9 is set to the upstream side of the heat generation moving means 21.
Since the recording medium 9 is narrowed as it approaches 21 and widened on the downstream side as it moves away from the heat generation transfer means 21, the recording medium 9 moves when the moving recording medium 9 approaches the heat generation transfer means 21 or leaves the heat generation transfer means 21. Even if the developer 8 on the recording medium 9 is shaken up and down, the developer 8 on the recording medium 9 can be prevented from coming into contact with the fixed heating element 26, and the image of the developer 8 can be prevented from being damaged.

In the third aspect, the heat transfer is performed by setting the spread angle of the fixed heating element 26 on the downstream side of the heat transfer means 21 to be larger than the narrowing angle of the fixed heating element 26 disposed on the upstream side of rotation. Since the post-heating time after fixing by the means 21 can be shortened, the cooling time can be controlled.

[0034]

EXAMPLES Examples 1 and 2 in which the present invention is applied to the multicolor electrophotographic apparatus described in the conventional example will be described below with reference to FIGS. The same reference numerals indicate the same objects throughout the drawings.

1) First Embodiment FIG. 2 is a block diagram showing a first embodiment of the present invention, and FIG. 3 is a first embodiment.
FIG. 4 is a configuration diagram showing a main part of FIG.

The toner 8a, heat generating roller 21a and fixed heat generating plates 26a to 26c shown in FIG.
And the fixed heating element 26, respectively. The example 1 is different from the conventional example in that the heat roller 21 is replaced by a heat roller 21.
a and fixed heat generating plates 26a to 26c, and fixed heat generating plates 26a to 26
That is, the sheet 9a to be fixed is preheated by c.

As shown in FIG. 2, in the fixing device 12b,
The heat generating roller 21a and the pressure roller 15a are in rolling contact with each other at a predetermined pressure. A temperature sensor St is provided at the rolling contact position of the heat generating roller 21a. Further, the plurality of fixed heat generating plates 26a to 26c are arranged on the upstream side of the heat generating roller 21a in the conveying direction of the paper 9a, and the distance between the heat generating roller 21a and the paper 9a is narrowed toward the heat generating roller 21a above the fixing surface of the paper 9a. Is provided.

The heating roller 21a is connected to the heating element control circuit 19a and the power source P ₁ , and the temperature sensor St is connected to the temperature control circuit 20. The heating roller is controlled by the heating element control circuit 19a.
A voltage is applied to 21a to generate heat, and depending on whether the temperature sensor St has reached a predetermined temperature, a control signal is sent from the temperature control circuit 20 to the heating element control circuit 19a by the temperature detection signal to control the voltage application. To be done.

Further, the fixed heating plate 26a~26c is connected to the heating element control circuit 19b and the power P _2, the control of the heating element control circuit 19b, so that the set temperature in each of the fixed heating plate 26a~26c A voltage is applied to.

As shown in FIG. 3 (a), the heat generation roller 21a
Is the cylindrical heat generating portion 22, the voltage applying portions 23a and 23b, and the shafts 24a and 24b.
It is composed of The cylindrical heating portion 22 is, for example, a cylindrical knitted body of conductive fibers (thermoplastic polyimide resin) coated with a thermosetting resin (for example, seamless planar heating element: manufactured by Gunze Co., Ltd.). Cylindrical heating part 22
Is, for example, φ10 mm, 20 to 10 ° C / s (applied voltage
The temperature can be raised to 150 ° C. within 1 minute at 40 to 30 W). Moreover, the nip width with the pressure roller 15a shown in FIG. 2 can be increased.

The voltage applying portions 23a and 23b are provided on both outer circumferences of the cylindrical heat generating portion 22 and are made of, for example, brass material.
The electrodes 25a and 25b are brought into contact with the voltage applying portions 23a and 23b, respectively, and a voltage is applied to the cylindrical heating portion 22.

The shafts 24a and 24b are press-fitted into both ends of the cylindrical heat generating portion 22 and are made of, for example, Teflon. Also, the axis 24
A gear G1 is formed on a, and the gear G1 is connected to a drive source (not shown) for rotating the heat roller 21a.

Further, as shown in FIG. 3 (b), a fixed heat generating plate is used.
26a (to 26c) has, for example, electrodes 25a and 25b at both ends, and a ceramic heater (for example, Mite) having a width of 7 mm and a thickness of 1 mm.
c: made by Kyocera) 27, and the distance between the sheet 9a and the sheet 9a is set to 5 mm at the entry portion (the right end in FIG. 2) of the sheet 9a. The fixed heating plate 26a is, for example, 100 ° C, and the fixed heating plate 26b is 120 ° C.
The temperature of the fixed heating plate 26c is controlled to 140 ° C.

FIG. 4 shows the relationship between the applied power and the arrival time until the temperature of the ceramic heater rises to a predetermined temperature. As shown in the figure, it can be seen that the applied power reaches 10 to 15 W and reaches the predetermined temperature within 1 minute.

With such a structure and function, when the sheet 9a to be fixed is conveyed to the fixing device 12b, the sheet 9a
The toner image on 9a is preheated from above by the fixed heat generating plates 26a to 26c, and then thermally fixed by the heat generating roller 21a.

For example, the rising time until the heating roller 21a is heated to 150 ° C. and the fixed heating plates 26a to 26c are heated to 100 ° C., 120 ° C. and 140 ° C. is within 1 minute, and the sheet 9a to be fixed is moved. When the speed is moved at 50 mm / s, it is possible to obtain a fixed image equivalent to that fixed at 155 ° C. under the condition that the nip width of the heating roller 14 and the pressure roller 15 of φ50 mm is 5 mm in the conventional method.

Therefore, unlike the conventional method, it is not necessary to raise the temperature of the aluminum tube and the rubber having a large heat capacity of the heating roller 14, and the cylindrical heat generating portion 22 of the heat generating roller 21a directly generates heat and the nip width is expanded. The peak temperature of the heat generation roller 21a and the fixed heat generation plates 26a to 26c is lowered by what is possible and the heating time is extended by preheating the fixed heat generation plates 26a to 26c (1 KW in the conventional method, 500 W or less in the first embodiment).
Therefore, the warm-up time (which takes about 5 minutes in the conventional method) can be shortened, and energy saving can be achieved.

In addition, since the heating time is long, a fixing state can be obtained which improves the color reproduction of color printing. Further, conventionally, in the case of fixing in the case of color, the heating roller 14 and the pressure roller 15 are increased in diameter to secure a nip width in order to give a heat amount which is several times that in the case of monochrome. The cross-sectional area was 15 × 13 cm ² ), but Example 1
With this, the nip width can be secured even if the diameters of the heat generating roller 21a and the pressure roller 15a are reduced, and the device can be downsized (the cross-sectional area of the device is 2 × 6 cm ² ).

Further, since the distance between the fixed heat generating plates 26a to 26c and the conveyed paper 9a is narrowed as the heat generating roller 21a is approached, the transferred toner image is fixed even if the paper 9a coming in rises. Do not touch the heating plates 26a-26c,
Therefore, the image is not scratched and damaged.

Further, since the temperature of the fixing device 12b is low, the amount of heat radiated is reduced, and other units in the apparatus, for example,
Since it is possible to reduce the temperature rise of the portion related to the toner 8a before the fixing step, it is possible to prevent the toner 8a from clumping and contribute to the stabilization of the entire printing process.

2) Second Embodiment FIG. 5 shows a second embodiment. The second embodiment differs from the first embodiment in that the fixed heat generating plate 26d,
26e was installed to perform post-heating in addition to preheating.

As shown in FIG. 5, in the fixing device 12c,
The fixed heat generating plates 26d and 26e are made of the same ceramic heaters as the fixed heat generating plates 26a to 26c, so that the distance between the heat generating roller 21a and the paper 9a increases as the distance from the heat generating roller 21a decreases, and the spread angle θ ₂ is Fixed heating plates 26a to 26 on the upstream side
It is set larger than the narrowing angle θ _{1 of} c (θ ₂ > θ ₁ ).

For example, the distance between the fixed heat generating plates 26a to 26c and the paper 9a is set to 10 mm at the entrance of the paper 9a, and the fixed heat generating plates 26d, 26 are formed.
The space between e and paper 9a is the exit of paper 9a (the left end in the figure)
Is 15 mm. Fixed heating plate 26 d, 26e are connected to the heating element control circuits 19c and power P ₃ with the fixed heating plate 26 a to 26 c, which is controlled similarly to the fixed heating plate 26 a to 26 c of Example 1.

With such a configuration, the sheet 9a to be fixed is preheated by the fixed heat generating plates 26a to 26c and heat-fixed by the heat generating roller 21a, and then post-heated (de-cooling) by the fixed heat generating plates 26d and 26e. Therefore, the heating time is further extended as compared with the case of the first embodiment, and the peak temperature of the heat generating roller 21a and the fixed heat generating plates 26a to 26e for fixing can be set low.

Further, even if the paper 9a that has passed through the heat generating roller 21a is lifted up, an unsolidified toner image is fixed on the heat generating plate.
26d and 26e are not touched, so the image is not rubbed and damaged, and the spread angle θ of the fixed heating plates 26d and 26e is
_By setting ₂ to be larger than the narrowing angle θ ₁ of the fixed heat generating plates 26a to 26c, the post-heating time after fixing by the heat generating roller 21a can be shortened.

Therefore, the spread angle θ _{2 is set so} that the heating time is extended and the cooling time is shortened.
It is determined how much the angle is set to be larger than the narrowing angle θ _{1 of} .

Here, for example, the heating roller 21a is set to 130
When the fixed heating plates 26a to 26c are controlled to 95 ° C., 115 ° C., 130 ° C. and the fixed heating plates 26d and 26e are controlled to 125 ° C. and 95 ° C., a fixed image equivalent to that of the first embodiment can be obtained. .

3) Third Embodiment FIG. 6 shows a heating roller different from the first and second embodiments. As shown in the figure, the cylindrical heat generating portion 22a of the heat generating roller 21b
Has a heater 29 built into the glass tube 28 and shafts 30a, 30
b is fitted.

The shafts 30a and 30b are made of a conductive material, for example, brass, and both ends of the heater 29 are joined to each other. The shaft 30a has a gear G2 connected to a drive source (not shown) for rotating the heat roller 21b. Are formed. The electrodes 25 are attached to the shafts 30a and 30b.
The a and 25b come into contact with each other, and a voltage is applied to the cylindrical heating portion 22a.

With this structure, the glass tube 28 is directly heated by applying a voltage to the heater 29. Therefore, the time required for raising the temperature to a predetermined temperature is the same as that of the aluminum base tube 140 and the rubber 141 of the conventional method. Compared with heating, it can be remarkably shortened, and the same effect as that of Example 1 and Example 2 can be obtained.

In the above example, the case of the multicolor electrophotographic printing apparatus has been described, but it is needless to say that the same can be applied to the case of the monochrome electrophotographic printing apparatus.

[0062]

As described above, according to the present invention, in claim 1, the developer on the recording medium is heated for a longer time, and the temperature of the heat transfer means and the fixed heat generating element is set low. Since it can be fixed, the warm-up time to the set temperature can be shortened.

Power consumption is reduced and energy saving is achieved. In the case of color, a fixing state that provides good color reproduction can be obtained. Since the fixing device can be downsized, it can contribute to downsizing of the electrophotographic printing device and the like.

A rise in temperature of devices other than the fixing device such as the electrophotographic printing device relating to the developer is reduced, which can contribute to stabilization of the entire printing process. According to the second aspect, even if the recording medium moves up and down when the moving recording medium approaches the heat generation moving means or moves away from the heat generation moving means,
It is possible to prevent the developer on the recording medium from coming into contact with the fixed heating element, and prevent the image of the developer from being damaged.

According to the third aspect, it is possible to shorten the post-heating time after the fixing by the heat generation moving means. This has the effect.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram showing a first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a main part of the first embodiment.

FIG. 4 is a diagram showing a temperature rise of a ceramic heater.

FIG. 5 is a configuration diagram showing a second embodiment of the present invention.

FIG. 6 is a perspective view showing a third embodiment of the present invention.

FIG. 7 is an internal side view showing a multicolor electrophotographic printing apparatus.

FIG. 8 is a configuration diagram showing a conventional example of a fixing device.

[Explanation of symbols]

8 is a developer, 8a is toner, 9 is a recording medium, 9a is paper, 21 is a heat transfer means,
21a and 21b are heating rollers, 26 is a fixed heating element, 26a
~ 26e is a fixed heating plate

Claims (3)

[Claims] 1. A device for heating and fixing an image formed by a developer on a recording medium, the self-heating for moving the recording medium in contact with the surface of the recording medium on which the image is formed by the developer. Heat generating and moving means, and at least one fixed heating element arranged in non-contact with the moving recording medium on at least the upstream side and the downstream side in the moving direction of the recording medium with respect to the heat generating and moving means. A fixing device characterized in that 2. The fixed heating element arranged on the upstream side in the moving direction of the recording medium with respect to the heating moving means is closer to the fixed heating element from the upstream side in the moving direction of the recording medium. The fixed heating element, which is arranged so as to be narrowed and is arranged on the downstream side in the moving direction of the recording medium with respect to the heating moving means, is spaced apart from the fixed heating element toward the downstream side in the moving direction of the recording medium. The fixing device according to claim 1, wherein the fixing device is arranged so as to expand as it goes. 3. The divergence angle of the fixed heating element arranged on the downstream side in the moving direction of the recording medium with respect to the heat generating moving means is arranged on the upstream side in the moving direction of the recording medium with respect to the moving heating means. The fixing device according to claim 2, wherein the fixing angle is set to be larger than the narrowing angle of the fixed heating element.