JP2002072725A - Electromagnetic induction heating coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic induction heating coil for a thermal fixing device whose warm-up time is short and which can realize quick start and power saving. SOLUTION: This electromagnetic induction heating coil is inserted through the heating roller of the thermal fixing device for a copying machine, and the electromagnetic induction heating coil 2 is constituted of a plurality of divided coiling parts 7 connected in series by leaving a space therebetween, a heat resistant bobbin 3 around which the coiling parts 7 are coiled, and a plurality of ferrite cores 6 housed in the bobbin 3, and is constituted by coiling the coiling parts 7 around the bobbin 3 so that the coiling direction is the rotating direction of the heating roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction heating coil for a heat fixing device provided in a copying machine, and more particularly to an electromagnetic induction heating coil used as a heat source for a heating roller of the heat fixing device. It is.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine or a printer is provided with a recording material (transfer material sheet, electrostatic recording paper, Fax paper, printing paper, etc.)
Is provided with a heat fixing device for fixing an unfixed image (toner image) corresponding to the target image information formed and supported by a transfer type or a direct type on a recording material surface as a permanent image. 2. Description of the Related Art A heating roller type fixing device having a structure in which a heating heater serving as a heat source is inserted inside and a pressure roller is elastically contacted with a rotatable heating fixing roller is often used.

In a heat fixing device using a halogen lamp as a heat source, when the halogen lamp generates heat and emits light, the heat is radiated and convected to heat an aluminum hollow metal roller as a heating roller, and the heated heating roller conducts heat. As a result, a permanent image is fixed on the surface of the recording material with a uniform temperature distribution throughout.

[0004]

By the way, in the above-mentioned heat fixing device, the time required for the entire heating roller to have a uniform temperature distribution, that is, a warm-up time is long, so as to cope with a so-called quick start and a recent time. It was difficult to respond to demanding power saving. Further, in a standby state in which the image forming apparatus has stopped the printing operation, it is necessary to adjust the standby temperature according to the standby state.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electromagnetic induction heating coil for a heating / fixing device which has a short warm-up time, allows quick start and saves power.

[0006]

According to a first aspect of the present invention, there is provided an electromagnetic induction heating coil which is used by being inserted into a heating roller of a heating and fixing device for a copying machine. A plurality of divided winding portions 7 provided and connected in series, and a heat-resistant bobbin 3 for winding the plurality of divided winding portions 7
And a plurality of ferrite cores 6 housed in the heat-resistant bobbin 3 and wound around the heat-resistant bobbin 3 with the winding direction being the rotation direction of the heating roller 1. . Since the electromagnetic induction heating coil 2 according to the first aspect is composed of a plurality of divided winding portions 7 connected in series at intervals, the electromagnetic induction heating coil 2
, The magnetic flux in the length direction is dispersed, and the temperature distribution of the entire electromagnetic induction heating coil 2 rises uniformly in a short time.

In a second aspect, the present invention is characterized in that the number of the divided winding portions 7 is switched by switching means 8 to change the length of the heating portion of the electromagnetic induction heating coil 2. An electromagnetic induction heating coil according to claim 1 is provided. In the electromagnetic induction heating coil 2 according to the second aspect, the length of the heat generating portion can be changed according to the size of the recording material, so that power can be saved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. Note that the present invention is not limited by this.

FIG. 1 shows a first embodiment of the present invention.
FIG. 3 is an explanatory diagram of an electromagnetic induction heating coil according to the embodiment;
2A is a partial cross-sectional view showing the configuration, FIG. 2B is a front view thereof, and FIG. 2 is an explanatory view showing the configuration of the heat fixing device. In the figure, reference numeral 2 denotes an electromagnetic induction heating coil which is a feature of the present invention, and a heating roller is mounted on a heat-resistant bobbin 3 made of an insulating heat-resistant resin having a heat-resistant temperature of 200 ° C. or more and containing a nickel-based or manganese-based ferrite core 6 inside. It is constituted by a plurality of divided winding portions 7 wound in one rotation direction (for example, a direction indicated by an arrow). Here, heat-resistant bobbin 3
As the insulating heat-resistant resin forming, PP (polypropylene), PBT (polybutylene terephthalate), PET (polyethylene terephthalate), phenol resin, and the like, which are excellent in mechanical strength and heat resistance, are preferable. As the ferrite cores 6, for example, seven rectangular parallelepipeds (not shown) of 50 mm × 14 mm × 5 mm are used, and a gap of about 0.5 mm is provided between the ferrite cores 6. It goes without saying that the shape of the ferrite core 6 may be cylindrical. On the other hand, the wire for the electromagnetic induction heating coil 2 has excellent heat resistance of class F (150 ° C.) or more such as polyamide copper wire, polyesterimide copper wire, and polyamideimide copper wire.
It is preferable to use a stranded wire formed by bundling 20 to 50 insulated wires of 0.1 to 0.5 mmΦ. The electromagnetic induction heating coil 2 is composed of 6 to 15 divided winding portions 7 connected in series, and each of the divided winding portions 7 is formed by tightly winding 4 to 7 turns, and 2 to 7.5 turns, respectively. The high-frequency power is supplied from a heating power supply circuit (not shown) side. In the electromagnetic induction heating coil 2 of the present invention, the variation in the surface temperature in the longitudinal direction of the heating roll 1 is ± 10 to 70 ° C. to ± 10 compared to the electromagnetic induction heating coil in which all are closely wound.
-30 ° C., and the temperature of the heating roll 1 can be increased so as to have a uniform temperature distribution.

Reference numeral 1 denotes a ferromagnetic heating roller made of iron.
A roller-type heat fixing device is constituted by a rubber or resin pressure roller 4. In this heat fixing device, a parallel pressure contact roller pair of the heat roller 1 and the pressure roller 4 has a basic structure. The pressure roller 4 is configured to elastically contact the rotatable heating roller 1. Then, the rollers 1 and 4 are rotated so that the recording material to be image-fixed is introduced into the heating nip portion which is a pressure contact portion of the rollers 1 and 4 while being nipped and conveyed. 4
The non-fixed image is soaked into the surface of the recording material by heat fusing by the pressing force of the fixing device, and is heat-fixed. The electromagnetic induction heating coil 2 of the present invention is inserted and used inside the heating roller 1 so as to form a gap between the heating roller 1 and the heating roller 1.

[0011] The electromagnetic induction heating coil 2 having such a configuration.
Is used in the heat fixing device, the electromagnetic induction heating coil 2 is composed of a plurality of divided winding portions 7 and the electromagnetic induction heating coil 2
As a result of the magnetic flux being dispersed in the length direction, the temperature distribution of the entire heating roller 1 becomes uniform in a short time. As a result, the warm-up time can be shortened, and the electromagnetic induction heating coil 2 for the heat fixing device can be provided which can cope with power saving and quick start.

FIG. 3 shows a second embodiment of the present invention. FIG. 3 (a) is a front view showing a configuration of an electromagnetic induction heating coil, and FIG. 3 (b) is a diagram showing electromagnetic induction heating. FIG. 4 is a circuit diagram illustrating a connection state when a coil is used.

In the figure, reference numeral 8 denotes switching means such as a switch. When the switching means 8 is connected to the A side, the electromagnetic induction heating coil 2 is constituted by eight divided winding portions 7, and the switching means 8 is connected to the B side. , The electromagnetic induction heating coil 2 is composed of ten divided winding portions 7. It should be noted that the difference from the first embodiment is that the number of divided winding portions 7 is switched by switching means 8,
The electromagnetic induction heating coil 2 which can change the length of the heating portion (paper passing range) is provided. For example, the paper passing range W in A3 size is
Set to 300mm to 340mm, paper passing range W in B5 size
Is set to 210 mm to 250 mm.

The electromagnetic induction heating coil 2 constructed as described above is composed of a plurality of divided winding portions 7, and the length of the heating portion can be changed according to the size of the recording material.
It is possible to provide the electromagnetic induction heating coil 2 which can save power even more than the embodiment.

[0015]

According to the present invention, there is provided an electromagnetic induction heating coil capable of obtaining a uniform temperature distribution in a short time by a simple means, shortening a warm-up time, saving power and supporting quick start. it can. In addition, since the number of divided winding portions that generate heat can be changed depending on the size of the recording material, an electromagnetic induction heating coil that can further reduce power consumption can be provided. The practical effect is large.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an electromagnetic induction heating coil according to a first embodiment of the present invention, wherein FIG. 1 (a) is a partial cross-sectional view showing the configuration, and FIG. 1 (b) is a front view thereof.

FIG. 2 is an explanatory diagram illustrating a configuration of a heat fixing device.

3A and 3B show a second embodiment of the present invention, and FIG. 3A is a partial explanatory view showing a main configuration of an electromagnetic induction heating coil.
(b) is a circuit diagram showing a connection state when the electromagnetic induction heating coil is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating roller 2 Electromagnetic induction heating coil 3 Heat-resistant bobbin 4 Pressure roller 6 Ferrite core 7 Split winding part 8 Switching means AC high frequency power supply W, W1 Paper passing range

Claims (2)

[Claims] 1. An electromagnetic induction heating coil which is inserted into and used by a heating roller of a heat fixing device for a copying machine, wherein said electromagnetic induction heating coil 2 comprises a plurality of divided winding portions 7 connected in series at intervals. A heat-resistant bobbin 3 configured to wind the plurality of divided winding portions 7 and a plurality of ferrite cores 6 housed in the heat-resistant bobbin 3. An electromagnetic induction heating coil characterized in that it is wound around. 2. The electromagnetic induction heating coil according to claim 1, wherein the number of said divided winding portions is switched by switching means to change the length of the heat generating portion.