JP2002229354A - Heating method of heating roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating method of heating roller in which a warm-up time is shortened and power saving can be attained corresponding to the quick- start and the size of a paper sheet for recording, by heating the heating roller by an electromagnetic induction heating coil of an high heating efficiency. SOLUTION: This is the electromagnetic induction heating method of the heating roller 6B constituting a heat fixing device, and three heating coils consisting of a center coil M2, and end part coils M1, M3 are arranged in the longitudinal direction in the heating roller 6B so that the center coil M2 is held between the end part coils M1, M3; one end of the center coil M2 is connected with one end of a switching means 5 of a driving circuit 10 provided with an oscillation circuit 12 and switching circuits 5, 5A and supplied with a power source voltage V from a power source circuit 11 and the other end is connected with the power source voltage V; also one end of serially connected end part coils M1, M3 is connected with one end of the switching means 5A and the other end is connected with the power source voltage V; and the energizing intervals of the center coil M2 and the end part coils M1, M3 are varied by the oscillation circuit 12 connected with the switching means 5, 5A to heat the heating roller 6B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a heating roller constituting an image forming apparatus such as a copying machine, and more particularly to a method for shortening a warm-up time, enabling a quick start, and a dimension of a recording sheet. The present invention relates to a heating method of a heating roller capable of saving power.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine or a printer is provided with a heat fixing device for forming an image, and is recorded by an appropriate image forming means such as an electrophotographic process, an electrostatic recording process, and a magnetic recording process. An image is formed on a paper (transfer material sheet, electrostatic recording paper, electrofax paper, printing paper, etc.) by transfer type or direct type, and the unfixed image (toner image) corresponding to the target image information is made permanent. Has established. In this type of heat fixing device, a halogen heater 9 serving as a heat source is inserted and disposed in a heating roller 6B made of aluminum or the like.
A heat fixing device 6A (see FIG. 7) having a structure in which 6C is elastically contacted has been frequently used.

In the above-described heat fixing device 6A, when the halogen heater 9 generates heat and emits light, the heat is radiated and convected to heat the heat roller 6B. The heat roller 6B itself has a uniform temperature distribution by heat conduction. Then, the permanent image is fixed on the recording paper 7.

[0004]

However, the heat fixing device 6A using the halogen heater 9 has a drawback that the time required for the entire heating roller 6B to have a uniform temperature distribution, that is, the so-called warm-up time is long. Was. Further, in the standby state where the printing operation is stopped, there is a problem that a complicated operation of adjusting the temperature of the heat fixing device 6A to the standby temperature corresponding to the standby state is required. For this reason, it has been difficult for the heating and fixing device 6A using the halogen heater 9 to provide a heating and fixing device 6A capable of saving power in accordance with the size of the recording paper 7 such as quick start which is recently required. .

Accordingly, an object of the present invention is to reduce the warm-up time by heating the heating roller with an electromagnetic induction heating coil having a high heating efficiency, thereby enabling quick start and power saving according to the size of recording paper. An object of the present invention is to provide a method for heating a heating roller.

[0006]

According to a first aspect of the present invention, there is provided a heating method for electromagnetically heating a heating roller 6B constituting a heating and fixing apparatus, comprising a center coil M2 and end coils M1, M1.
3 are arranged in the longitudinal direction in the heating roller 6B so as to sandwich the central coil M2 between the end coils M1 and M3,
The center coil M2 has one end connected to one end of the switch means 5 of the drive circuit 10 to which the power supply voltage V is supplied from the power supply circuit 11 and the other end connected to the power supply voltage V. At the same time, one end in which the end coils M1 and M3 are connected in series is connected to one end of the switch means 5A and the other end is connected to the power supply voltage V, and the center coil M2 and the end coil M1 are connected.
A heating roller heating method is characterized in that the heating roller 6B is heated by changing an energization interval for M3 by an oscillation circuit 12 connected to the switch means 5, 5A. According to the first aspect, since the heating roller is heated by electromagnetic induction using the heating coil, the heating efficiency is high, the warm-up time is shortened, and quick start is possible. In addition, by changing the energizing interval for the center coil M2 and the end coils M1 and M3, it is possible to reduce power consumption due to the size of the recording paper, and to suppress an excessive rise in temperature in the non-paper passing area of the heating roller. Can be.

In a second aspect, the center coil M2 is wound in the circumferential direction or the longitudinal direction, and the end coils M1 and M3 are wound in the longitudinal direction or the circumferential direction. Item 1. A method for heating a heating roller according to item 1. According to the second aspect, since the winding directions of the center coil M2 and the end coils M1 and M3 are different by 90 ° and the magnetic fluxes from the coils do not intersect, mutual induction between the coils does not occur, and the circuit element is damaged. And abnormal heating of the heating roller can be eliminated.

In a third aspect, the center coil M2 and the end coils M1 and M3 are respectively wound in the circumferential direction, and are disposed via a ferrite core 3 larger than each coil diameter. Item 1. A method for heating a heating roller according to item 1. According to the third aspect, since the magnetic flux emitted from each coil is forcibly released to the heating roller 6B via the ferrite core 3, mutual induction between the coils does not occur, and damage to the circuit element and the end coil are prevented. Abnormal heating of M1 and M3 can be eliminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. FIG. 1 is a main part configuration diagram showing a first embodiment of a heating roller 6B used in the present invention, FIG. 2 is a perspective view of main parts of a heat fixing device 6, and FIG. 3 is a center coil M2 and end coils M1, M3. FIG. 4 is an explanatory diagram showing the current supply interval to the center coil M2 and the end coils M1 and M3, FIG. 5 is an explanatory diagram showing the temperature distribution of the heating roller 6B, and FIG. 6 is a heating roller used in the present invention. FIG. 9 is a main part configuration diagram showing a second embodiment of 6B. Note that the present invention is not limited by this.

-First Embodiment- In the drawings, reference numeral 6B denotes a heating roller made of a ferromagnetic material for electromagnetic induction, SUS430 or the like, which constitutes the heat fixing device 6,
In the longitudinal direction inside the heating roller 6B, three coils are arranged so as to sandwich the central coil M2 between the end coils M1 and M3. The center coil M2 is wound on the coil bobbin 2 in the circumferential direction of the heating roller 6B with a length of 200 mm, a diameter of 20 mm, and 70 to 90 turns, and the end coils M1 and M3 are 50 m long on the coil bobbin 2A.
m, width 20 mm, thickness 15 mm, 20 to 30 turns, each wound in the longitudinal direction of the heating roller 6B. The magnetic flux of the center coil M2 and the end coils M1 and M3 is
The magnetic flux direction is 90
Differently, no mutual induction occurs between the coils.
Note that each of the center coil M2 and the end coils M1 and M3 may be wound in the longitudinal direction of the heating roller 6B. In this case, it is needless to say that mutual induction does not occur between the coils.

Each of the three heating coils M1, M2, M3 includes at least switch means 5, 5A comprising a semiconductor element and the like and an oscillation circuit 12, and is connected to a drive circuit 10 to which a power supply voltage V is supplied from a power supply circuit 11. A resonance capacitor (not shown) is connected to each of the center coil M2 and the series-connected end coils M1 and M3. Further, the power supply voltage V is supplied to the center coil M2 via the switch means 5, the power supply voltage V is supplied to the end coils M1 and M3 via the switch means 5A, and the switch means 5, 5A is Oscillator circuit 1
Connected to two. In this oscillation circuit 12, the central coil M
The time during which the power supply voltage V is supplied to the coil 2 and the end coils M1 and M3, that is, the energization interval can be changed according to the size 7A of the recording paper 7. Then, the temperature distribution of the heating roller 6B is changed as shown in FIG. 5 by changing the energization interval as shown in FIG. Note that the temperature distribution of the heating roller 6B is obtained by measuring the temperature T at a position W in the width direction of the heating roller 6B (FIG. 7A). 4 and 5, underlined lines indicate the state in which the recording sheet 7 is used horizontally, and those without underlines indicate the state in which the recording sheet 7 is used vertically. Specifically, FIG.4 (a) shows a case where the size 7A of the recording paper is A4 horizontal and A3 vertical, and the energizing intervals for the center coil M2 and the end coils M1 and M3 are uniform (1: 1). , And the energization to both is performed alternately. On the other hand, FIG. 4C shows the case where the recording paper size 7A is A5 horizontal and A4 vertical and the temperature distribution of the heating roller 6B needs to be changed because the horizontal width of the recording paper 7 is small. The energization intervals for M1 and M3 are not uniform, and the end coils M1 and M3 have a half ratio (2:
1) indicates that power is supplied. Similarly, FIG.
4 (b), the end coils M1, M3 are energized at a ratio of 4: 3 with respect to the center coil M2, and FIG. 4 (e) shows that the end coils M1 and M3 are energized at a ratio of 1: 0 to the center coil M2. As described above, the temperature distribution of the heating roller 6B changes as shown in FIGS. 5B to 5F in accordance with the change in the current supply interval to the center coil M2 and the end coils M1 and M3. In addition to saving power according to the dimension 7A of 7, the excessive temperature rise of the non-sheet passing portion of the heating roller 6B is prevented.

Second Embodiment FIG. 6 shows another embodiment, in which a center coil M2 has a length of 200 mm, a diameter of 20 mm, a diameter of 70 to 90 turns and a circumference of a heating roller 6B on a coil bobbin (not shown). Direction coil, end coil
M1 and M3 are each 50mm long and 20m in diameter on the coil bobbin 2.
m, wound in the circumferential direction of the heating roller 6B in about 40 to 50 turns. The center coil M2 and the end coils M1 and M3 have a ferrite core 3 (30 mm
Φ) is disposed in the heating roller 6B in the longitudinal direction so that the center coil M2 is separated by the end coils M1 and M3. Therefore, the magnetic flux emitted from each of the center coil M2 and the end coils M1 and M3 is forcibly released to the heating roller 6B by the ferrite core 3. As a result, mutual induction between the coils does not occur, and damage to the circuit elements and abnormal heating of the end coils M1 and M3 can be eliminated.

The interval between the energization of the central coil M2 and the end coils M1 and M3 is the same as that of the first embodiment, and therefore detailed description is omitted. However, the temperature distribution of the heating roller 6B is changed as shown in FIG. Needless to say, it is possible to save power according to the recording paper 7 of various sizes and also to prevent an excessive rise in temperature of the non-sheet passing portion of the heating roller 6B.

Each of the center coil M2 and the end coils M1 and M3 has 10 to 60 heat-resistant urethane wires having a wire diameter of 0.1 mm to 0.6 mm.
The wire is formed by wire for litz wire which has been twisted.
This has the effect of suppressing the temperature rise of each coil itself. In addition, polyamide-imide copper wire, wire for litz wire,
It goes without saying that a polyesterimide copper wire or the like may be used.

Although not shown in detail, the center coil
One end of each of M2 and end coils M1 and M3 is fixed to the housing side of the heat fixing device 6 and disposed inside the heating roller 6B so as not to contact the heating roller 6B, and each coil itself rotates. Never.

Further, the heat fixing device 6 has a parallel press roller pair of a heat roller 6B and a pressure roller 6C as a basic structure. Recording paper 7 to be image-fixed to nip 8
The unfixed image is heated and melted by the heat of the heating roller 6B and the pressing force of the heating nip 8, so that the unfixed image penetrates into the recording paper 7 and is fixed.

The coil bobbins 2, 2A are integrally molded with a heat-resistant resin such as phenolic resin or ceramic, PPS, REEK, and a nickel- or manganese-based ferrite core having a Curie point of 200 ° or more. It is desirable to arrange them at a predetermined interval of 4 mm.

Since the heating method of the present invention is a heating method using electromagnetic induction heating, the heating efficiency is high, the warm-up time can be shortened, and a quick start is possible. In addition, by changing the power supply interval to the heating coil, it is possible to save power according to the size of the recording paper, to prevent an excessive rise in temperature of the non-paper passing portion of the heating roller, and to form a high quality image. become.

[0019]

According to the present invention, the warm-up time can be reduced by simple means, quick start can be performed, and power can be saved according to the size of the recording paper, and an image of excellent quality can be formed. There is a great practical effect.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment of a heating roller used in the present invention.

FIG. 2 is a perspective view of a main part of the heat fixing device.

FIG. 3 is a circuit connection diagram of a center coil M2 and end coils M1 and M3.

FIG. 4 is an explanatory diagram showing energization intervals for a center coil M2 and end coils M1 and M3.

FIG. 5 is an explanatory diagram illustrating a temperature distribution of a heating roller.

FIG. 6 is a main part configuration diagram showing a second embodiment of the heating roller.

FIG. 7 is a perspective view showing a configuration of a main part in a conventional example.

[Explanation of symbols]

 2,2A Coil bobbin 3 Ferrite core 5,5A Switch means 6,6A Heat fixing device 6B Heat roller 6C Pressure roller 7 Recording paper 7A Recording paper dimensions 8 Heat nip section 9 Halogen heater 10 Drive circuit 11 Power circuit 12 Oscillation circuit AC commercial Power supply M1, M3 End coil M2 Center coil V Power supply voltage

Claims (3)

[Claims] 1. A heating method for electromagnetically heating a heating roller 6B constituting a heat fixing device, wherein three heating coils including a central coil M2 and end coils M1 and M3 are centered by end coils M1 and M3. The central coil M2 is disposed in the longitudinal direction in the heating roller 6B so as to sandwich the coil M2, and one end of the central coil M2 includes an oscillation circuit 12 and switch means 5, 5A, and is supplied with a power supply voltage V from a power supply circuit 11. One end of the switch means 5 of the circuit 10 has the other end connected to the power supply voltage V, and one end of the end coils M1 and M3 connected in series is connected to one end of the switch means 5A and the other end is connected to the power supply voltage V. Then, a heating roller 6B is heated by changing an energizing interval for the central coil M2 and the end coils M1 and M3 by an oscillation circuit 12 connected to the switch means 5 and 5A. 2. The center coil M2 is wound in a circumferential direction or a longitudinal direction, and the end coils M1 and M3 are wound in a longitudinal direction or a circumferential direction. Heating method of the heating roller. 3. The center coil M2 and the end coils M1, M
3. The heating method for a heating roller according to claim 1, wherein each of the coils is wound in a circumferential direction and disposed via a ferrite core larger than each coil diameter.