JP2003140484A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device in which warmup time of a fixing roller is greatly reduced by employing a simple constitution and electric power consumption is reduced. SOLUTION: A main heater 12 and a subheater 13 are arranged inside a fixing roller 10. An electric double layer capacitor C, which is capable of storing electric power by receiving power from an AC power supply 20, is provided in a heater control circuit. During a standby, recharging operations to the capacitor C are conducted without feeding electric power to the heaters 12 and 13. When a printing is started, power feeding is conducted to the heater 12 from the power supply 20, the capacitor C is discharged and the discharging electric power is fed to the heater 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming machine such as a copying machine, a printer and a facsimile. In particular, the present invention relates to an improvement for shortening the warm-up time, which is the time required for the fixing device to change from the standby state to the fixable state.

[0002]

2. Description of the Related Art Conventionally, a fixing device used in an image forming machine such as a copying machine, a printer or a facsimile includes a fixing roller having a heater therein, and a toner image previously formed on a recording sheet is fixed to the fixing roller. The toner image is fixed on the recording paper by being heated by.

In this fixing device of the fixing roller system,
Since it is necessary to heat the metal fixing roller having a large heat capacity, there is a problem that energy saving cannot be sufficiently improved. Another problem is that it takes a long time (warm-up time) to heat the fixing roller to a predetermined fixing temperature (for example, 200 ° C.) at the start of printing, and as a result, from the input of the print start signal to the end of printing. It can be said that the time required to get there will be longer.

As a means for shortening the warm-up time, it is possible to reduce the heat capacity of the cylindrical fixing roller by reducing its thickness. According to this, the warm-up time can be shortened without increasing the power supply capacity (supply power) of the apparatus body.

[0005]

However, although the method of shortening the warm-up time by reducing the thickness of the fixing roller can be shortened to some extent, when the rigidity of the fixing roller is taken into consideration. However, there is a limit to the thinning. For this reason, even if there is a demand for further shortening the warm-up time in order to cope with the speeding up of the image forming machine, there is a limit to the time that can be shortened in terms of the rigidity of the fixing roller.

Further, even when the image forming machine is on standby, the heater is energized to constantly heat the fixing roller so that the printing operation can be performed without waiting time (without warm-up time). However, this consumes unnecessary power and deteriorates energy saving.

The present invention has been made in view of the above points, and it is an object of the present invention to greatly reduce the warm-up time of the fixing roller with a simple structure and to improve energy saving. It is to provide a fixing device capable of performing the above.

[0008]

Means for Solving the Problems-Outline of the Invention-To achieve the above object, the present invention stores electric power in advance prior to warm-up operation, and during the warm-up operation, the stored electric power is stored. And the electric power from the power supply temporarily cause a high power fixing roller (fixing member)
The heating operation is performed so that the warm-up time can be shortened.

-Solution Means-Specifically, it is premised on a fixing device provided with a fixing member for heating and fusing a toner image onto a recording medium. At least one first heating unit that heats the fixing member to the fixing device by power supply from a power source, and a power storage unit that receives electric power from the power source and stores the electric power in advance.
At least one second heating unit for heating the fixing member by the power supply from the power storage unit is provided.

According to this specific matter, before the warm-up operation is started, the electric power from the power source is supplied to the electric storage means to store a predetermined amount of electric power in the electric storage means. The power consumed during standby before this warm-up operation is
Only the electric power stored in this power storage means. Then, when the warm-up operation is started, the power feeding operation to the first heating means by the power feeding from the power source and the power feeding operation to the second heating means by the discharging from the power storage means are performed, and the power storage is performed. The fixing member is heated with a relatively large electric power until the discharge from the means is completed. In other words, the heating operation of the fixing member is assisted by the electric power stored in the power storage means. Therefore, the temperature of the fixing member can be rapidly raised, and the time required for the warm-up operation can be shortened. Further, as described above, the power consumed during the standby is only the power stored in the power storage means,
It is not necessary to energize the heating means during standby. Therefore, energy saving can be achieved. still,
It is preferable that the start of power supply from the power supply and the start of discharge from the power storage unit at the start of the warm-up operation are synchronized, but the present invention is not limited to this. Further, the first heating means and the second heating means are not limited to one heating means (electric heater or the like), and a plurality of these heating means may be provided.

The following configuration is given as another solution. First, it is assumed that a fixing device is provided with a fixing member for heating and fusing a toner image on a recording medium. The fixing device is provided with heating means for heating the fixing member by power supply and storage means for storing electric power to be supplied to the heating means in advance. The electric power and the electric power discharged from the power storage unit are supplied to the heating unit substantially at the same time.

According to this particular matter, the electric power is stored in the power storage means before the warm-up operation is started, and when the warm-up operation is started, the power supply from the power source and the discharge from the power storage means are substantially simultaneously performed. By doing so, the heating operation of the fixing member is performed with relatively large electric power. Therefore, the time required for warm-up operation can be shortened,
In addition, it is possible to save energy because the electric power consumed during standby is small. In the present solving means, not only a case where a plurality of heating means are provided and power is supplied from a power source to some heating means and power is supplied to the other heating means from a power storage means, a single heating means is used. On the other hand, the case where the power supply from the power supply and the power supply from the power storage means are performed at substantially the same time, and the case where the power supply from the power supply and the power supply from the power storage means are performed at the same time to each of the plurality of heating means are included.

A capacitor is used as the storage means. More specifically, an electric double layer capacitor is adopted. By adopting the power storage means utilizing the charge / discharge function of the capacitor, it becomes possible to realize the power storage operation and the power supply operation to the heating means by a simple control circuit.
In addition, the electric double layer capacitor is capable of performing rapid charge and discharge, and has a long life because it does not involve a chemical reaction. Further, it has excellent characteristics that maintenance is not required and environmental load is small, and it is suitable as a power storage unit of this type of device.

As a concrete configuration of a circuit for supplying power to the heating means, first, a rectifier circuit for converting an alternating current into a direct current to supply power to the storage means, and power stored in the storage means are supplied to the heating means. And a switch means that is turned on only when it is turned on.

Further, as another circuit configuration, in place of the switch means, when supplying the electric power stored in the power storage means to the heating means, a switching operation for converting the discharge voltage of the power storage means into a predetermined voltage by a switching operation. It is equipped with a circuit. For this switching circuit, DC / D
Examples include those provided with a C converter and those provided with a heating means after lowering the discharge voltage of the power storage means to a predetermined voltage by a switching operation.

When the above DC / DC converter is adopted, the lower limit value of the terminal voltage of the capacitor can be lowered, so that the capacitance of the capacitor used as the storage means can be reduced. That is, the warm-up time can be sufficiently shortened even if a small capacitor is used. Further, in the case where the discharge voltage is lowered to a predetermined voltage by a switching operation, it is possible to prevent a part of the electric energy stored in the capacitor from being consumed, and to limit the usable range of the capacitor terminal voltage. Since the power can be expanded, the amount of electric power that can be stored in the power storage unit can be increased.

Further, the heating means is arranged at a plurality of positions along the longitudinal direction of the fixing member, and power is individually supplied to each heating means. If the wall thickness of the fixing member (fixing roller) is made thinner to shorten the warm-up time, the heat conduction in the thrust direction (axial direction) deteriorates, and when passing small size paper continuously, the area other than the paper passing area Has the problem of being overheated. When the heating means is arranged at a plurality of positions in the longitudinal direction of the fixing member to individually supply power as in the present solution means, power is supplied to the heating means for heating the area other than the sheet passing area. By suppressing the amount, it is possible to prevent overheating of this region and control to an appropriate temperature.

Further, when the heating means are arranged at a plurality of positions in the longitudinal direction of the fixing member in this way, at least one of the heating means is supplied with the discharge power from the power storage means during the warm-up operation. It is configured to be. Thus, by controlling the discharge timing from the power storage unit, it becomes possible to easily control the temperature of the specific region of the fixing member by the heating unit that receives the discharge power from the power storage unit.

As the heating means, specifically, an electric heater or a magnetic induction heating means for heating the fixing member by magnetic induction heating can be adopted.

The following is a specific configuration when the magnetic induction heating means is adopted. First, a magnetic induction heating drive circuit for supplying power to the magnetic induction heating means is provided, and the power storage means is constituted by a capacitor provided in the magnetic induction heating drive circuit and having both smoothing function and storage function. With this configuration, one capacitor can perform the smoothing function and the storage function, and the magnetic induction heating drive circuit can be simplified.

Further, the magnetic induction heating means is a coil for magnetic induction heating, and the coil is arranged so as to face the outer surface of the fixing member. That is, by adopting the magnetic induction heating of the external heating method, when the fixing member is a hollow fixing roller, the inside thereof can be filled with a heat insulating material,
It is possible to prevent the release of heat energy to the air inside.
Therefore, the warm-up operation can be completed in an even shorter time, and the power consumption during fixing can be reduced.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, as a configuration for heating the fixing roller as a fixing member provided in the fixing device to a predetermined fixable temperature, one in which an electric heater is housed inside the fixing roller and the other facing the outer surface of the fixing roller. And a magnetic induction heating coil is arranged. In the following first to third embodiments, the case where the present invention is applied to the configuration in which the fixing roller is heated by the electric heater will be described. In the fourth to seventh embodiments, the heating operation of the fixing roller by the magnetic induction heating coil is described. A case in which the present invention is applied to a configuration for performing will be described.

(First Embodiment) First, the first embodiment will be described. As shown in FIG. 1, the fixing device 1 has a cylindrical fixing roller 10 and a roll-shaped fixing roller 10 that has an axis extending in the same direction as the axis of the fixing roller 10 and is in contact with the outer peripheral surface of the fixing roller 10. The pressure roller 11 is provided.

Inside the fixing roller 10, an electric heater (hereinafter referred to as a main heater) 12 as a first heating unit and an electric heater (hereinafter referred to as a sub-heater) as a second heating unit, which are hot wire filaments, are provided. ) 13 extends parallel to the axis of the fixing roller 10.

As a result, when the transfer sheet P on which the toner image is formed is nipped and conveyed between the fixing roller 10 and the pressure roller 11 which are heated by the heaters 12 and 13,
The toner image is fixed on the transfer paper P (heat welding) by heat and pressure applied from the surfaces of the rotating rollers 10 and 11.
It is supposed to be done.

As a feature of this embodiment, in the fixing device 1, the main heater 12 and the sub-heater 13 are turned off in the standby state.
In this state, the power consumption is reduced and the capacitor (electric double layer capacitor) Cc as a storage means provided in the storage circuit 26 described later is charged in preparation for the print start operation. Then, after charging, the stored voltage of the capacitor Cc is maintained at a predetermined voltage.

Further, after the charging operation, the main heater 12 is supplied with regular power from the power source (power having a value near the upper limit of the power source capacity) in response to the input of the print start signal. At the same time, in order to shorten the time for warming up the roller surface to a predetermined temperature (warm-up time), the capacitor Cc of the storage circuit 26 is discharged and its power is supplied to the sub-heater 13. Control of the up operation is performed by a heater control circuit described later.

The fixing roller 10 according to this embodiment will be described below. First, Example 1 as one of the specific configurations of the fixing roller 10 used in the present embodiment will be described. As the fixing roller 10 of Example 1, those shown in Table 1 are adopted. That is, it is made of an aluminum material and has a diameter of 40 mm and a wall thickness of 0.5 mm. The fixing roller 10 has an axial length of 320 mm. Further, inside the roller, a halogen lamp having a rated voltage of 100 V and a rated power of 1000 W, which serves as the main heater 12, is provided.
Sub heater 13 rated voltage 100V, rated power 50
A 0 W halogen lamp is arranged.

[0029]

[Table 1]

Further, the storage circuit 26 in the first embodiment
Is equipped with an electric double layer capacitor having a capacitance of 2F, and has a charge end voltage of 110V and a discharge end voltage of 90V.
It is set to V respectively. Table 2 (a) shows the specifications relating to the heating characteristics. Further, the fixing roller 10 of this example is
Density is 2.7 g / cm ³ , thermal conductivity is 2.3 J / cm ・ s ・ k,
Roller heat amount is 6.11J, roller cross-sectional area is 0.62c
m ² , lateral thermal conductivity is 1.43 J · cm / s · k, and thicknesswise thermal conductivity is 46.0 J / cm ² · s · k.

[0031]

[Table 2]

In Table 1, the thermal conductivity λ is multiplied by the cross-sectional area S of the fixing roller to indicate the value of the heat conduction in the lateral direction, which is used as the lateral heat conduction λS. The value of “1” was set as the normalized λS. Further, a value indicating good thermal conductivity in the thickness direction obtained by dividing the thermal conductivity λ by the thickness t of the fixing roller is used as the thermal conductivity λ / t in the thickness direction, and the value of Comparative Example 2 described later is “1”. Was used as the normalized λ / t. It should be noted that the second embodiment of the fixing roller 10 used in this embodiment and a comparative example as a conventional fixing roller will be described later.

<Description of Heater Control Circuit> The main heater 12 and the sub-heater 13 are on / off controlled by the heater control circuit shown in FIG. The heater control circuit will be described below.

In the heater control circuit shown in FIG.
Is an AC power source, 21 is a main power switch composed of switches SW1 and SW1, 22 is a switching circuit composed of zero-cross switch SW2 (hereinafter referred to as a zero-cross switch), 23 is a bypass power switch composed of switch SW3, and 24 is a primary winding. a consisting of a and a secondary winding b,
25 is a rectifier circuit composed of diodes D1 and D2,
Reference numeral 26 is a power storage circuit composed of a smoothing coil L and a capacitor (double-layer capacitor) Cc which is a power storage element, and 27 is a switching circuit as a switching means composed of a semiconductor switch element SW4.

As the capacitor Cc provided in the storage circuit 26, a large capacity electric double layer capacitor is used. Since this electric double layer capacitor Cc does not involve a chemical reaction, it has a long life, no deterioration due to repeated charging / discharging, an internal resistance smaller than that of a secondary battery, and rapid charging / discharging in seconds. It has advantages that it is possible and small, and that it does not require liquid exchange or liquid replenishment unlike a secondary battery such as a lead storage battery and has good maintainability. In addition, this electric double layer capacitor Cc has an excellent feature that the environmental load at the time of disposal is small because activated carbon is used for the electrodes and it does not contain harmful substances such as lead.

The main heater 12 is connected to the AC power source 20 via a main power source switch 21 and a zero cross switch 22. On the other hand, the sub heater 13
Is connected to the AC power source 20 via a bypass power switch 23, a transformer 24, a rectifier circuit 25, a storage circuit 26, and a switching circuit 27.

In this heater control circuit, the main power switch 21 is ON while the zero-cross switch 22 is OFF when the image forming machine is on standby, and the supply of current to the main heater 12 is cut off. There is. Further, the zero-cross switch 22 is turned on in response to the input of the print start signal, and power control is performed by energizing the main heater 12 from the AC power source 20 and switching the zero-cross switch 22.

On the other hand, the bypass power switch 23 is always turned on when the image forming machine is on standby. Further, the switching circuit 27 is OFF during this standby. Therefore, no current is supplied to the sub-heater 13, and the double-layer capacitor Cc of the storage circuit 26 is gently charged through the bypass power switch 23, the transformer 24, and the rectifier circuit 25, and thereafter, the terminal of the capacitor Cc. Voltage (eg 11
0V) is maintained.

When the print start signal is turned on, the zero cross switch 22 is turned on as described above,
The power supply operation from the AC power source 20 to the main heater 12 is started. In parallel with this, the switching circuit 2
7 is turned on, the double layer capacitor Cc of the storage circuit 26 is discharged, and this electric power is supplied to the sub heater 13. In this way, the warm-up assist operation is performed. During this discharging operation, the bypass power switch 23 is turned off, and the charging operation to the capacitor Cc is prohibited. The switching circuit 27 performs a simple ON / OFF operation and is designed so that the loss in the circuit can be ignored. By this warm-up operation, the fixing roller 10 is simultaneously heated by the two kinds of heaters 12 and 13 and rapidly raised from the standby temperature to the fixing temperature.

Then, the temperature of the fixing roller 10 reaches a predetermined fixing temperature, or the electric double layer capacitor C
When c discharges a predetermined amount and the terminal voltage reaches the lower limit value (90 V), the switching circuit 27 is turned off, and the warm-up auxiliary operation ends.

After discharging, the capacitor Cc has the zero-cross switch 22 turned off for temperature control during the printing operation.
In the meantime, or while the printing operation is completed and the power supply to the main heater 12 is stopped, the bypass power switch 23 is turned on in preparation for the next warm-up operation, and the gradual charging is performed via the rectifier circuit 25. It

Since such an operation is performed, the power consumption by the main heater 12 and the sub-heater 13 is completely "0" in the standby state, and the electric double layer capacitor Cc of the storage circuit 26 is turned on. The electric double layer capacitor Cc is used after the power is consumed once for charging.
Since the leakage current is very small, the power consumption will be maintained at about "0".

In the case of Example 1 described above, the rising time (warm-up time) until the surface temperature of the fixing roller 10 reaches the fixing temperature is about 8.1 sec, and the surface temperature of the fixing roller 10 during this period is Ambient temperature (eg 2
From 0 ° C., it is uniformly heated to the fixing temperature (for example, 150 ° C.).

<Second Embodiment> Next, a second embodiment as another specific configuration of the fixing roller 10 used in the present embodiment will be described. As shown in Table 1, the fixing roller 10 of this example is made of an aluminum material having a thickness of 0.5 mm, a roller diameter of 30 mm, a specific heat of 0.88 J / g · k, and a density of 2.7 g / cm ³ , thermal conductivity 2.3 J / cm · s · k, roller heat quantity 4.57 J, roller cross-sectional area 0.46 cm ² ,
It is composed of a cylindrical roller having a lateral thermal conductivity of 1.07 J · cm / s · k and a thickness thermal conductivity of 46.0 J / cm ² · s · k.

The heater as a heat source provided inside the fixing roller 10 is a 1000 W main heater 12.
And a sub heater 13 of 150 W.

According to the second embodiment, the ambient temperature (20
C.) to the fixing temperature (150.degree. C.) (rise time) was about 7.9 sec.

Next, a comparative example, which is a fixing roller having a conventional structure, will be described for comparison with the above-described respective examples.

<Comparative Example 1> As shown in Table 1, Comparative Example 1 as a conventionally used general fixing roller has a wall thickness of 1 mm, no sub-heater, and a 1000 W halogen lamp. Has been adopted. Also, the roller diameter is 40
Cylindrical roller composed of mm aluminum material, specific heat 0.88 J / g · k, density 2.7 g / cm ³ , thermal conductivity 2.3 J / cm · s · k, roller heat 12 0.1 J, roller cross-sectional area 1.23 cm ² , lateral thermal conductivity 2.82.
J ・ cm / s ・ k, thermal conductivity in the thickness direction is 23.0 J / cm ²・ s ・ k
It is composed of The rising time required to heat the fixing roller of Comparative Example 1 from the ambient temperature (20 ° C.) to the fixing temperature (150 ° C.) by only the main heater was about 24.1 seconds.

Comparative Example 2 Next, Comparative Example 2 will be described. The fixing roller according to Comparative Example 2 is configured as a thin-walled fixing roller in order to shorten the warming-up time. Carbon steel is used as a material for avoiding the strength deterioration due to the thinning. Also, the wall thickness is 0.2 mm, and it does not have a sub-heater.
It uses a 000W halogen lamp. The roller diameter is 40 mm, the specific heat is 0.48 J / g · k, and the density is 7.
9 g / cm ³ , thermal conductivity 0.5 J / cm · s · k, roller calorific value 3.93 J, roller cross section 0.25 cm ² , lateral thermal conductivity 0.13 J · cm / s · k It is composed of.
The rise time required to heat the fixing roller of Comparative Example 2 from the ambient temperature (20 ° C.) to the fixing temperature (150 ° C.) only by the main heater was about 7.8 sec. <Comparison between Example 1 and Comparative Example 1> Comparing the rise times of Example 1 and Comparative Example 1 described above, the thickness and heat capacity of the fixing roller of Example 1 are ½ of those of Comparative Example 1 and the AC power supply. Since both of the electric power supplied are 1000 W, the rise time of the temperature in Example 1 is about 12 seconds, which is 1/2 of that in Comparative Example 1 unless the storage circuit 26 operates. However, in Example 1, the electricity storage circuit 26 operates and the electric double layer capacitor Cc is discharged to supply power to the sub-heater 13, so that the rise time is set to 1 of Comparative Example 1.
It has been reduced to 8.1 seconds, which is / 3. <Comparison between Examples 1 and 2 and Comparative Example 2> When the rising times of Example 1 and Comparative Example 2 are compared, the heat capacity of the fixing roller of Example 1 is 1.6 times that of Comparative Example 1, and AC. Since the electric power supplied from the power source is both 1000 W, the temperature rise time of Example 1 is about 12 seconds, which is 1.6 times that of Comparative Example 1 unless the storage circuit 26 operates. However, in the first embodiment, the electricity storage circuit 26 operates and the electric double layer capacitor Cc is discharged to supply power to the sub-heater 13, so that the rise time is 4% as compared with the second comparative example.
The 8.1 seconds remaining in UP has been achieved.

In the second embodiment, the fixing roller diameter is 30.
7. By reducing the diameter to mm, it is almost equal to Comparative Example 2.
9 sec has been achieved. <Comparison of Thermal Conductivity in Thickness Direction> The thermal conductivity in the thickness direction of the fixing roller in Comparative Example 1 is about one half of the thermal conductivity in the thickness direction of the fixing roller in Example 1. Therefore, the heat conduction efficiency is low, and it takes a long time for the surface temperature of the fixing roller to reach the fixing temperature (150 ° C.). Moreover, at the time of printing, if a temperature difference occurs on the roller surface, the temperature difference cannot be promptly eliminated, and there is a high possibility that fixing unevenness will occur. <Comparison in Thermal Conductivity in Thickness Direction and Thermal Conductivity in Lateral Direction> Comparing Examples 1 and 2 with Comparative Examples 1 and 2, Comparative Example 2 of the thin-wall system shows that the fixing rollers of Examples 1 and 2 are the same. Approximately one-tenth of the lateral heat conduction λS and thickness-direction heat conduction λ / t, respectively, and one-third and one-fifth of the general comparative example 1, respectively.
Has become. For this reason, the heat conduction in the fixing roller of Comparative Example 2 is poor, and if a temperature difference occurs on the roller surface due to paper entry or ejection during printing, the temperature difference cannot be promptly eliminated, and uneven fixing may occur. Is high.

In Examples 1 and 2, the lateral heat conduction λS is about 1/2 of that of the general fixing roller of Comparative Example 1, and temperature unevenness in the lateral direction easily occurs, but the thickness direction heat conduction λ /
t is about twice, and the delay in transferring the heat applied to the inner surface to the roller surface is improved, and the lateral heat conduction λ
Considering S and heat conduction in the thickness direction λ / t together, Examples 1 and 2 can obtain the same fixed image quality as Comparative Example 1 in terms of heat conduction.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in the configuration for discharging the electric power stored in the power storage means to the sub heater 13 in the heater control circuit. Therefore, only the differences from the first embodiment will be described here.

As shown in FIG. 3, in this embodiment, the first
DC / instead of the switching circuit 27 in the embodiment
A DC converter 37 is provided.

The operation of each part in this embodiment is such that the bypass power switch 23 is turned on during standby and when there is a margin of power supply during printing, the electric double layer capacitor Cc of the storage circuit 26 is slowly charged, and after charging. Terminal voltage (1
10 V) is maintained. After that, at the start of printing, the zero-cross switch 22 is turned on to supply power to the main heater 12, the detour power switch 23 is turned off, and DC is turned on.
The DC / DC converter 37 is turned on, and the electric energy stored in the capacitor Cc is used to make the sub-heater 13 100
When a constant electric power of V is supplied, the fixing roller has a predetermined temperature (1
When the terminal voltage of the capacitor Cc reaches the lower limit value (10 V), the DC / DC converter 37 is turned off.
The FF is performed and the warm-up auxiliary operation is completed.

The DC / DC converter 37 can convert an input voltage range of 110 (V) to 10 (V) into an output voltage of 100 (V), and the converter efficiency is 85%. It is designed so that the electric energy stored in the electric double capacitor Cc of the storage circuit 26 is not consumed when the sub-heater 13 is not supplied with electric power.

Although some of the electric energy stored in the electric double layer capacitor Cc is consumed by the DC / DC converter 37, the lower limit value of the terminal voltage of the capacitor Cc is set low as shown in Table 2 (b). It is possible to reduce the electrostatic capacitance to 1 / 2.6 as compared with the heater control circuit of the first embodiment.

(Third Embodiment) Next, a third embodiment of the present invention will be described. Also in this embodiment, the configuration for discharging the electric power stored in the power storage means to the sub-heater 13 in the heater control circuit is different from that of the first embodiment. Therefore, only the differences from the first embodiment will be described here.

In the present embodiment, as shown in FIG. 4, the first
The difference is that a switching circuit 47 using a transistor is provided instead of the switching circuit 27 in the embodiment, and that the transformation ratio (secondary side terminal voltage) of the transformer 24 is doubled. The circuit configuration and the operation of each part are the same as those of the heater control circuits of the first and second embodiments.

The bypass power switch 23 is turned on at the time of standby and when there is a margin of power supply during printing, the electric double layer capacitor Cc of the storage circuit 36 is slowly charged, and the terminal voltage (220 V) is maintained after charging. At the start of printing, the zero-cross switch 22 is turned on to supply power to the main heater 12, the detour power switch 23 is turned off, and the transistor of the switching circuit 47 is turned on / off.
By the OFF operation, the electric energy stored in the capacitor Cc is used to cause the sub-heater 13 to have a temperature of about 100.
The electric power of (V) is supplied to the fixing roller at a predetermined temperature (15
(0 ° C) or when the terminal voltage of the capacitor Cc reaches the lower limit value (90V), the switching circuit 47 is turned off.
Then the warm-up auxiliary operation is completed.

The switching circuit 47 adjusts the output voltage in the range of 110 (V) to 85 (V) by switching control (feedback control of the output voltage) in the input voltage range of 220 (V) to 90 (V). It has a switching efficiency of 95% and is designed not to consume the electric energy stored in the electric double layer capacitor Cc of the storage circuit 26 when the sub-heater 13 is not supplied with electric power.

As shown in Table 2 (c), it is possible to improve the consumption of a part of the electric energy stored in the electric double layer capacitor Cc by the switching circuit 47 and to set the lower limit value of the terminal voltage of the capacitor Cc to the lower limit value. Since it can be set to a low value, the capacitor C can be used for the heater control circuit of the first embodiment.
The capacitance of c can be reduced to 1 / 9.6 and 1 / 3.8 to the heater control circuit of the second embodiment, respectively.

As described above, in each embodiment, the main heater 12 for heating the fixing roller 10 to the fixing temperature and the fixing roller 10 are provided inside the fixing roller 10.
13 for auxiliary heating of the
3 is provided with a heater control circuit including a storage circuit 26 for supplying auxiliary power. Therefore, during standby, the capacitor Cc of the storage circuit 26 is gently charged to store electrical energy, and the main heater 12 is heated by regular power supply (power supply from the AC power supply 20) at the start of printing. In parallel with this, by heating the sub-heater 13 by supplying electric power by discharging the electric energy stored in the capacitor Cc, it is possible to shorten the start-up time of the fixing temperature, save energy of the image forming machine, and print. It is possible to speed up the operation.

A storage circuit 26 having a double layer capacitor Cc in the heater control circuit for controlling the sub heater 13 is also provided.
By providing the battery, there is no deterioration due to repeated charging / discharging, long life, less loss due to internal resistance, and rapid charging / discharging are possible. Therefore, it is possible to provide a power storage means that does not need to be used, has good maintainability, uses activated carbon for the electrodes, and does not contain harmful substances such as lead, and therefore has a small environmental load at the time of disposal.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. In this embodiment, the present invention is applied to a configuration in which a fixing roller is heated by a magnetic induction heating coil as magnetic induction heating means.

FIG. 5 is a schematic structural view of the interior of the fixing device 1 in this embodiment as seen from the axial direction of the rollers 10 and 11. As shown in this figure, a pair of magnetic induction heating coils 51 and 52 for heating the fixing roller 10 by magnetic induction heating are disposed above the fixing roller 10. One coil 51 is a main coil as a first heating means that is directly fed from a power source, and the other coil 52 is a sub coil as a second heating means to which electric power stored in a capacitor Cc described later is supplied. is there.
A temperature sensor 53 for detecting the surface temperature of the fixing roller 10 is provided near the surface of the fixing roller 10.

The magnetic induction heating drive circuit in this embodiment will be described below. As shown in FIG. 6, the magnetic induction heating drive circuit according to the present embodiment includes an AC power source 20, a rectifier circuit 25 including a diode bridge circuit, a smoothing circuit 54 including a smoothing coil L and a smoothing capacitor C, and power feeding to the main coil 51. Main power supply line Lm and sub coil 5 for performing
The sub power supply line Ls for supplying power to the power supply 2 and the zero cross switch 22 arranged between the AC power supply 20 and the rectifier circuit 25 are provided. In addition, the main power supply line L
The m is provided with a main switching circuit 55 including a pair of transistors Tr and Tr for controlling the power supply to the main coil 51 by switching. Further, the sub power supply line Ls is provided with the bypass power switch 23 and the switching circuit 57, and the sub coil 5
A sub-switching circuit 56 including a pair of transistors Tr and Tr for controlling the power supply to 2 by switching is provided. The sub-switching circuit 56 is configured such that the collector of the transistor Tr is connected between the bypass power supply switch 23 and the switching circuit 57 in the sub-power supply line Ls. The double layer capacitor Cc forming the power storage means in this embodiment has one end connected to the switching circuit 57 and the other end grounded. That is, both the bypass power supply switch 23 and the switching circuit 57 are turned on to supply power to the sub power supply line Ls, and the transistor T of the sub switching circuit 56.
When r and Tr are OFF, the double layer capacitor Cc is charged. Further, on the ground side of the main coil 51 and the sub coil 52, current transformers CT1 and CT2 for measuring the value of the current supplied to the coils 51 and 52 are provided.

The above-mentioned switches 22, 23, 57 and the transistor Tr are ON / OFF controlled by the control unit 60. Further, the measurement signals of the current transformers CT1 and CT2 are input to the control unit 60. Further, the image forming apparatus is provided with a sensor (not shown) for detecting the document size, and the document size signal (SIZE) from this sensor and the fixing roller heating command signal (HON) accompanying the start of the printing operation are also input. It has become so.

Next, the operation of the magnetic induction heating drive circuit configured as described above at the standby time and at the start of printing will be described.

First, when the image forming machine is on standby, the main power switch (not shown) and the zero-cross switch 2
2. The bypass power switch 23 and the switching circuit 57 are both ON. Further, each transistor T of the main switching circuit 55 and the sub switching circuit 56 is
Both r are OFF, and the supply of current to the coils 51 and 52 is cut off. In this state, the electric power supplied to the sub power supply line Ls is the double layer capacitor C.
It is slowly charged to c, and thereafter the terminal voltage (for example, 110 V) of the capacitor Cc is maintained.

When the print start signal is input, the transistors Tr of the main switching circuit 55 and the sub switching circuit 56 are ON / OFF-controlled, and only the bypass power switch 23 is turned OFF. , 52 is supplied. That is, the main coil 51 is supplied with electric power from the AC power supply 20 through the main power supply line Lm, while the sub-coil 52 is supplied with discharging electric power discharged by the double-layer capacitor Cc. In this way, the warm-up assist operation is performed.

Since such an operation is performed, the power consumption by the main coil 51 and the sub-coil 52 is completely "0" in the standby state, and the power consumption for charging the electric double layer capacitor Cc is reduced. Since the leakage current of the electric double layer capacitor Cc is very small after the one-time operation, the power consumption is maintained at about "0".

On the other hand, the print start signal causes the fixing roller 10 to be rapidly raised from the standby temperature to the fixing temperature by the magnetic induction heating by the two types of coils 51 and 52.

Then, the temperature of the fixing roller 10 reaches a predetermined fixing temperature, or the electric double layer capacitor C
When the terminal voltage reaches the lower limit value (90V) by performing a predetermined discharge of c, the transistor Tr of the sub-switching circuit 56 is turned off, and the warm-up assist operation ends.

The discharged capacitor Cc is gently turned on in preparation for the next warm-up operation while the transistor Tr of the main switching circuit 55 is off for controlling the temperature during the printing operation. Will be charged.

FIG. 7 shows each switch 22,
It is a timing chart which shows ON / OFF control of 23 and 57, the power supply state to each coil 51 and 52, etc. In this figure, HON is a fixing roller heating command signal, SW1 is an ON / OFF operation of the zero-cross switch 22, SW2 is an ON / OFF operation of the bypass power switch 23, SW3 is an ON / OFF operation of the switching circuit 57, and COIL -m is the power supply state to the main coil 51, COIL-s is the power supply state to the sub coil 52, Vc is the charging voltage of the capacitor Cc, T is the temperature of the fixing roller 10, and limit-AC In is the AC power supply 20. The power supply state from each is shown. In this timing chart, T1 shows the timing when the charging operation of the capacitor Cc is performed, and T2 shows the timing when the discharging operation of the capacitor Cc is performed.

The timing chart shown in FIG. 7 shows the case where the sub coil 52 is energized only during warm-up and the temperature of the fixing roller 10 is adjusted only by the main coil 51 during the printing operation. is there. In the timing chart of FIG. 7, the charging operation is not performed after the discharging operation of the capacitor Cc is finished, but the charging may be performed while the transistor Tr of the main switching circuit 55 is OFF.

On the other hand, when the temperature of the fixing roller 10 is adjusted not only during warm-up but also during the printing operation by the sub-coil 52, the timing chart is as shown in FIG. That is, the main coil 51
When de-energized, the bypass power supply switch 23 and the switching circuit 57 are both turned on to charge the electric double layer capacitor Cc (timing T1 ′ in the figure), and the electric double layer capacitor Cc is charged as necessary. Discharge. Figure 8
In the case shown in, in synchronization with the energization of the main coil 51,
Sub coil 52 due to discharge of electric double layer capacitor Cc
Is energized to adjust the temperature of the fixing roller 10 (timing T2 ′ in the figure).

The third embodiment as one of the specific configurations of the fixing roller 10 adopted in this embodiment will be described below. As the fixing roller 10 of the third embodiment, those shown in Table 3 are adopted. In other words, it is made of carbon steel and has a diameter of 40 m.
m, wall thickness is set to 0.3 mm. The fixing roller 10 has an axial length of 340 mm.

[0079]

[Table 3]

Further, as the capacitor Cc for storing electricity in the third embodiment, an electric double layer capacitor having a capacitance of 2.2F is provided, and its charge end voltage is set to 140V and discharge end voltage is set to 90V. There is. Table 4 shows the specifications related to the heating characteristics. The fixing roller 10 of this example has a density of 7.9 g / cm ³ and a thermal conductivity of 0.5 J / c.
m · s · k and roller heat amount is 5.293J.

[0081]

[Table 4]

Further, the fixing roller 10 of the fourth embodiment as another specific configuration of the fixing roller 10 adopted in this embodiment.
Is different from that of the third embodiment only in that the axial length is 320 mm.

Next, Comparative Example 3 will be described as a comparative example with respect to Examples 3 and 4 above. As shown in Table 3, in Comparative Example 3, the fixing roller 10 of Example 3 was used.
The roller having the same configuration as that of 1. is adopted, and the warm-up operation is performed only by the AC power source 20 having the same capacity as the magnetic induction heating drive circuit described above.

The results of measuring the warm-up time in these examples and comparative examples will be described below. In Comparative Example 3, the ambient temperature (20 ° C.) was changed to the fixing temperature (15 ° C.).
Time to rise to 0 ° C (rise time) is about 21.3
It was sec. On the other hand, in Examples 3 and 4, it was about 12.8 sec and about 8.5 sec, respectively, which was significantly shorter than that of Comparative Example 3.

FIG. 9 shows the results of an experiment conducted on the rising state of the surface temperature of the fixing roller 10 when the total power supplied to the main coil 51 and the sub coil 52 during warm-up is different from each other. In this experiment, the fixing roller 10 of Example 3 described above was used, and the main coil 5
1 and the total power supplied to the sub-coil 52 is 600 W,
The change in the surface temperature of the fixing roller 10 from the start of power supply to the coils 51 and 52 was measured for each of 700 W and 800 W. Further, when the surface temperature of the fixing roller 10 reaches a predetermined fixing temperature (200 ° C.), the temperature control operation is switched to. As a result, as shown in FIG. 9, it was confirmed that the larger the total power, the shorter the time required to raise the surface temperature of the fixing roller 10 to the target fixing temperature.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. In this embodiment, in the magnetic induction heating drive circuit, the arrangement position of the power storage means and the sub power supply line Ls are provided.
The configuration is different from that of the fourth embodiment. Therefore, only the differences from the fourth embodiment will be described here.

As shown in FIG. 10, in the present embodiment, the electric double layer capacitor Cc is used as the capacitor that constitutes the smoothing circuit 54 of the fourth embodiment. That is, by adopting a capacitor having a large capacity, the capacitor Cc can be made to have both smoothing action and electricity storage action. As described above, since the capacitor Cc provided on the power supply side with respect to the connection position of the sub power supply line Ls with respect to the main power supply line Lm functions as a power storage unit, the capacitor Cc is discharged during the discharging operation. Electric power can be supplied to each of the main coil 51 and the sub coil 52.

Various switches are not provided in the sub power supply line Ls of this embodiment. That is, the AC power source 20
The power supplied from the capacitor and the discharge power from the capacitor Cc are both supplied to the sub-coil 52.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described. In the present embodiment, as shown in FIG. 11, the sub coil 52 is not provided, and the main coil 51
The fixing roller 10 is heated only by itself. That is, at the time of warm-up, the fixing roller 10 is heated with a large amount of power by supplying both the power supplied from the AC power source 20 and the discharge power from the capacitor Cc to the main coil 51.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described. In the above-described first to third embodiments, the main heater 12 and the sub-heater 13 respectively heat the entire fixing roller 10, and in the fourth to sixth embodiments, the main coil 51 and the sub-coil 52 respectively. The whole was heated.

In the present embodiment, instead, the area heated by each heating means is divided in the longitudinal direction of the fixing roller 10. In the following description, the fixing roller 10 is heated by the main coil 51 and the sub coil 52, and the case where the area heated by each coil 51, 52 is divided in the longitudinal direction of the fixing roller 10 will be described. The fixing roller 1
The same can be applied to the case of heating 0.

As shown in FIG. 12, the length dimension of the main coil 51 has a length dimension that substantially matches the width dimension of B5 size paper. On the other hand, the length dimension of the sub-coil 52 is substantially the same as the width dimension of the A3 size sheet minus the width dimension of the B5 size sheet. In the case of this embodiment, the transfer paper P is conveyed left justified in the drawing.

Then, the size of the transferred transfer paper is detected in advance by a paper size sensor provided in the transfer path of the transfer paper P, and when the transfer paper is the B5 size paper, the main coil is used. Power is supplied only to 51. On the other hand, when the transfer paper is A3 size paper, power is supplied to both the main coil 51 and the sub-coil 52. Any of the fourth and fifth embodiments described above can be adopted as the magnetic induction heating drive circuit.

When the wall thickness of the fixing roller 10 is reduced in order to shorten the warm-up time, the heat conduction in the axial direction is deteriorated, and when small size paper is continuously fed, the area other than the paper feeding area is overheated. There is a problem that it will be done. As in the present embodiment, when the region where the heating operation is performed by the coils 51 and 52 is divided in the longitudinal direction of the fixing roller 10, power is supplied to the coil that performs the heating operation in the region other than the paper passing region. By suppressing the amount, it is possible to prevent overheating of this region and control to an appropriate temperature.

Further, when the A3 size sheet is conveyed, power is supplied to both the main coil 51 and the sub coil 52, and the heating operation for the entire fixing roller 10 is performed by relatively large power as in the case of each of the above-described embodiments. Therefore, the warm-up time can be shortened. On the other hand, when the B5 size sheet is conveyed, power is supplied only to the main coil 51, and only part of the fixing roller 10 is heated. That is, since the heating operation is performed on a small area with the same electric power as the conventional one (for example, the electric power supplied from the AC power source is 1000 W), the warm-up time can be shortened also in this case.

Next, an example of an experiment conducted to confirm the effect of the seventh embodiment will be described. In this experiment,
(1) Power is supplied to each of the main coil 51 and the sub-coil 52 to allow the A3 size sheet to pass through while the fixing roller 10 is entirely heated, and the temperature of each part of the fixing roller 10 after the passage is measured, (2) Main coil 5
1 and the sub-coil 52 are supplied with electric power to heat the fixing roller 10 as a whole to pass B5 size paper, and the temperature of each part of the fixing roller 10 after the passage is measured. (3) Only to the main coil 51 Power is supplied to heat only a part of the fixing roller 10 (passage area of the B5 size paper) to pass the B5 size paper,
Measurement of the temperature of each part of the fixing roller 10 after the passage,
Respectively.

The experimental results are shown in FIG. Experiment (1)
The results are shown by a solid line, the results of the experiment (2) are shown by a chain line, and the results of the experiment (3) are shown by a broken line. As can be seen from the results of this experiment, when the power supply to the coils 51 and 52 is switched according to the size of the passing paper sheet as in the above experiments (1) and (3), the area that needs heating (paper passing area) )
Only the fixing temperature is maintained at a predetermined fixing temperature, and a low temperature is maintained in a region where heating is not required (non-sheet passing region). On the other hand, as in the experiment (2), when power was supplied to the coil facing the area where heating is not required (non-sheet passing area), this area was overheated and power wasted wastefully. The transfer paper may be consumed or the influence of this overheating may adversely affect the transfer paper. From the above results, the area heated by the coils 51 and 52 is set to the fixing roller 10
Each coil 5 according to the paper size
It has been confirmed that switching the power supply to 1, 52 is effective in this device.

In the present embodiment, the case where the main coil 51 and the sub coil 52 are arranged one by one in the longitudinal direction of the fixing roller 10, that is, the case where the heating means is arranged at two positions has been described. The means may be arranged at three or more places.

-Other Embodiments-In the above-described first to fourth embodiments, the main heater 12 or the main coil 51 is fed from the AC power source 20 only, and the sub-heater 13 or the sub-coil 52 is fed from only the capacitor Cc. In the fifth embodiment,
Each coil 51, 52 is an AC power source 20 and a capacitor Cc.
The power can be supplied from each of the above. The present invention is not limited to this. For example, power is supplied to the main heater 12 from both the AC power source 20 and the capacitor Cc,
For the sub-heater 13, power is supplied only from the capacitor Cc.
The form of power feeding to 1, 52 can be designed arbitrarily.

[0100]

As described above, according to the present invention, electric power is stored in advance in the warm-up operation of the fixing device in which the heating operation of the fixing member is performed by the heating means. The accumulated electric power and the electric power from the power source are used to temporarily perform the heating operation of the fixing member with the large electric power. Therefore, the temperature of the fixing member can be rapidly raised, and the time required for the warm-up operation can be shortened. That is, by increasing the amount of electric power stored in advance, the time required for warming up can be shortened without limit. Further, since the electric power consumed during the standby is only the electric power stored in the power storage means and it is not necessary to energize the heating means during the standby, it is possible to achieve a great energy saving.

In particular, when an electric double layer capacitor is used as the electricity storage means, it is possible to provide a suitable fixing device that can perform rapid charging / discharging, has a long life, and does not require maintenance. .

Further, when the heating means is arranged at a plurality of positions along the longitudinal direction of the fixing member and the electric power is individually supplied to each heating means, the heating of the area other than the paper passing area is performed. It is possible to suppress the amount of power supply to the heating means that operates, and it is possible to control this region to an appropriate temperature.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram in which the inside of a fixing device using an electric heater is viewed from the axial direction of each roller.

FIG. 2 is a diagram showing a heater control circuit according to the first embodiment.

FIG. 3 is a diagram showing a heater control circuit according to a second embodiment.

FIG. 4 is a diagram showing a heater control circuit according to a third embodiment.

FIG. 5 is a schematic configuration diagram in which the inside of a fixing device using a magnetic induction heating coil is viewed from the axial center line direction of each roller.

FIG. 6 is a diagram showing a magnetic induction heating drive circuit according to a fourth embodiment.

FIG. 7 is a timing chart diagram for explaining the operation of the magnetic induction heating drive circuit of the fourth embodiment.

FIG. 8 is a timing chart diagram for explaining another operation of the magnetic induction heating drive circuit of the fourth embodiment.

FIG. 9 is a diagram showing the results of an experiment in which changes in roller surface temperature were measured when the total power supplied to each coil during warm-up was varied.

FIG. 10 is a diagram showing a magnetic induction heating drive circuit according to a fifth embodiment.

FIG. 11 is a diagram showing a magnetic induction heating drive circuit according to a sixth embodiment.

FIG. 12 is a view showing an arrangement state of a main heater and a sub heater in the seventh embodiment.

FIG. 13 is a diagram showing results of an experiment conducted to confirm the effect of the seventh embodiment.

[Explanation of symbols]

1 fixing device 10 Fixing roller (fixing member) 12 Main heater (first heating means) 13 Sub-heater (second heating means) 20 AC power supply 25 Rectifier circuit 26 Storage circuit 27 Switching circuit (switching means) 37 DC / DC converter (switching circuit) 47 Switching circuit 51 Main coil (magnetic induction heating means) 52 sub coil (magnetic induction heating means) Cc electric double layer capacitor P transfer paper (recording medium)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 6/04 301 H05B 6/04 301 6/14 6/14 (72) Inventor Shogo Yokota Osaka City, Osaka Prefecture 22-22 Nagaike-cho, Abeno-ku, Sharp Co., Ltd. (72) Inventor Tetsunori Mitsuoka 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka BA25 BA27 BB18 BE06 CA28 CA44 CA45 3K058 AA02 AA81 BA18 CB09 CD01 CE31 DA01 3K059 AA03 AA08 AA14 AD02 AD07 AD12 CD16 CD18 CD33 5G065 AA01 DA04 DA06 EA06 GA04 GA06 HA17 JA02 KA02 KA05 MA10 NA01

Claims (14)

[Claims] 1. A fixing device having a fixing member for heating and fusing a toner image onto a recording medium, comprising at least one first heating means for heating the fixing member by supplying power from a power source, and a power source. A fixing device comprising: a power storage unit that receives electric power from the storage unit and stores the power in advance; and at least one second heating unit that heats the fixing member by supplying power from the power storage unit. apparatus. 2. A fixing device provided with a fixing member for heating and fusing a toner image onto a recording medium, wherein heating means for heating the fixing member by power supply, and electric power for supplying to the heating means. A fixing device, comprising: a storage means that is stored in advance, and configured to supply the heating means with the power supplied from the power supply and the discharge power from the power storage means substantially at the same time during warm-up. 3. The fixing device according to claim 1, wherein the storage means is composed of a capacitor. 4. The fixing device according to claim 3, wherein the capacitor is an electric double layer capacitor. 5. The fixing device according to claim 1, wherein a rectifier circuit for converting an alternating current into a direct current and supplying the electricity to the electricity storage means, and heating the electric power stored in the electricity storage means. And a switch unit which is turned on only when the fixing unit is supplied to the fixing unit. 6. The fixing device according to claim 1, wherein a rectifier circuit for converting an alternating current into a direct current and supplying the electricity to the electricity storage means, and heating the electric power stored in the electricity storage means. When supplying the means,
A fixing device, comprising: a switching circuit that converts a discharge voltage of a power storage unit into a predetermined voltage by a switching operation. 7. The fixing device according to claim 6, wherein the switching circuit includes a DC / DC converter. 8. The fixing device according to claim 6, wherein the switching circuit supplies the heating device with the discharge voltage of the power storage device after the discharge voltage is reduced to a predetermined voltage by a switching operation. 9. The fixing device according to claim 1, wherein the heating means is arranged at a plurality of positions along the longitudinal direction of the fixing member, and the heating means is provided for each heating means. A fixing device characterized in that it is configured so that power is supplied individually. 10. The fixing device according to claim 9, wherein at least one of the heating means arranged at a plurality of positions is configured to be supplied with the discharge power from the power storage means during the warm-up operation. Characterizing fixing device. 11. The fixing device according to claim 1, wherein the heating unit is an electric heater. 12. The fixing device according to claim 1, wherein the heating means is a magnetic induction heating means for heating the fixing member by magnetic induction heating. . 13. The fixing device according to claim 12, further comprising a magnetic induction heating drive circuit for supplying power to the magnetic induction heating means, and the power storage means is provided in the magnetic induction heating drive circuit and has a smoothing function and a storage function. A fixing device comprising a capacitor having both of the following: 14. The fixing device according to claim 12, wherein the magnetic induction heating means is a coil for magnetic induction heating,
A fixing device in which the coil is arranged so as to face the outer surface of the fixing member.