JP3900692B2 - Heat roller device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat roller device used in a toner heat fixing device such as a copying machine or a laser beam printer, a steel plate laminating device, a plastic film laminating device, and the like.
[0002]
[Prior art]
Many fixing units of copying machines such as copiers and laser beam printers are usually configured as shown in FIG. That is, the sheet 1 such as paper is transferred between the heat roller 3 heated to a high temperature and the pressure roller 4 by transferring the toner powder 2 by static electricity or the like. As a result, the toner powder 2 transferred onto the sheet 1 is heated and melted, and is pressed and fixed on the sheet 1. As a heating source for the heat roller 3, a halogen lamp heater 5 disposed at the center of the heat roller 3 is used. Further, the thermistor sensor 6 arranged in contact with the surface of the heat roller 3 detects the surface temperature of the heat roller 3, and controls the output of the halogen lamp heater 5 so that this temperature becomes a predetermined temperature. It is what.
[0003]
[Problems to be solved by the invention]
Conventionally known heat roller devices represented by the copying apparatus have a problem that it is very difficult to control the temperature of the heat roller. That is, for the convenience of the user, the copying apparatus can be adapted to various sizes. For example, a heat roller that can be used for A3 size paper is used so that a size from A5 size paper to A3 size paper can be copied. At this time, when A5 size paper is copied, if the temperature of the portion through which the paper passes is made constant, the temperature of the heat roller is excessively increased because the heat is not taken away by the paper in the portion through which the paper does not pass. Therefore, in order to make the temperature of the heat roller uniform, it is necessary to manufacture the heat roller from aluminum having good heat conductivity, and to increase the plate thickness in order to improve heat conductivity. Accordingly, the heat capacity of the heat roller is increased, and it takes time to rise in temperature. Therefore, the present invention intends to provide a heat roller device that solves the above-described conventional problems.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film having a predetermined Curie temperature by adjusting the composition, and the temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film. A non-magnetic material having a lower electrical resistivity than the temperature-sensitive magnetic metal material comprising the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film provided with self-temperature control by induction heating, and temperature-sensitive A magnetic metal pipe or temperature-sensitive magnetic metal film and a non-magnetic material with low electrical resistivity are arranged with a space, and an induction heating part is provided outside the temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film. is there.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The invention described in claim 1 includes a temperature-sensitive magnetic metal pipe or a temperature-sensitive magnetic metal film having a predetermined Curie temperature by adjusting the composition, and a metal constituting the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film. A non-magnetic material having a lower electrical resistivity than the material is disposed with a space between each other, and the temperature-sensitive magnetic metal pipe or film is curieized by induction heating the temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film. When the temperature rises above the temperature and becomes non-magnetic, the induced current flows through the non-magnetic material having a lower electrical resistivity than the temperature-sensitive magnetic metal material, so the amount of generated heat is reduced, and thus self-temperature controllability is provided, and and the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film, the electric resistivity lower non-magnetic material and arranged with a space, the temperature sensitive magnetic metal pipe or sensitive Heated roller device using an induction heating section for inductively heating a magnetic metal film laminating apparatus such as a comprising Ru configuration outside of the heat-fixing device or steel or plastic toner of the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film The heat capacity of the heat roller device can be reduced by implementing the method, and a heat roller device having a quick rise time can be obtained.
[0006]
In addition, as in the invention described in claim 2, a temperature-sensitive magnetic metal plate and a nonmagnetic material having a lower electrical resistivity than the temperature-sensitive magnetic metal plate are directly laminated, or are laminated with a space, An induction heating coil is disposed inside the pressure roller to form an induction heating unit that induction heats the temperature-sensitive magnetic metal plate, and the insulating film and pressure roller that are supported by the temperature-sensitive magnetic metal plate and rotate. By heating with an object to be heated in between, the insulating film can be thinned to reduce the heat capacity, and the temperature rise time can be shortened.
[0007]
Moreover, the invention described in claim 3 is a temperature-sensitive magnetic metal pipe, a temperature-sensitive magnetic metal film, or a temperature-sensitive sensor so that the self-temperature control characteristic is best exhibited in the heat roller device according to any one of claims 1 to 2. The thickness of the magnetic metal plate is limited to the range of 50% to 200% of the skin depth.
[0008]
According to a fourth aspect of the present invention, there is provided an induction heating coil for heating a temperature-sensitive magnetic metal pipe in the heat roller device according to any one of the first and third aspects, and an end portion of the temperature-sensitive magnetic metal pipe. An end induction heating coil that is formed by winding the coil more densely than the induction heating coil is disposed in a portion opposite to the induction heating coil. When the temperature is raised, both the induction heating coil and the end induction heating coil are energized. By using the heat roller device configured as described above, at the time of start-up, it is possible to compensate for the heat taken by the bearing that supports the temperature-sensitive magnetic metal pipe and to increase the temperature rise time.
[0009]
【Example】
Example 1
FIG. 1 is a perspective view of a main part of a heat roller device according to Embodiment 1 of the present invention. The heat roller device according to this embodiment is used for a fixing device of a copying machine. The material of the temperature-sensitive magnetic metal pipe 7 is a magnetic alloy adjusted so that the Curie temperature is about 200 ° C., which is a temperature slightly higher than the temperature at which the toner is melted. In this embodiment, iron and nickel or an alloy of iron, nickel and chromium is used as the magnetic alloy. This combination has a high saturation magnetic flux density and is suitable for the application of this embodiment. In addition, when using for another use, naturally the temperature to obtain with a hot roller apparatus also changes, and the composition of an alloy can also be changed so that it may become a Curie temperature according to this use.
[0010]
The temperature-sensitive magnetic metal pipe 7 is heated by an induction heating unit that induction-heats the temperature-sensitive magnetic metal pipe 7. The induction heating unit includes an induction heating coil 10 wound around a ferrite 9 disposed inside a pressure roller 8 made of silicon rubber or the like, and a high frequency power source 11 that supplies a high frequency current to the induction heating coil 10. Yes. The induction heating coil 10 uses a litz wire having a configuration in which thin copper wires are bundled. Inside the temperature-sensitive magnetic metal pipe 7, a nonmagnetic material 12 having a lower electrical resistivity than that of the temperature-sensitive magnetic metal that is the material of the temperature-sensitive magnetic metal pipe is interposed between the temperature-sensitive magnetic metal pipe 7. It is arranged.
[0011]
The operation of this embodiment will be described below. When a switch (not shown) is operated, the high frequency power supply 11 starts operating and supplies a high frequency current to the induction heating coil 10. A high frequency magnetic field corresponding to the supplied high frequency current is generated from the induction heating coil 10. This high-frequency magnetic field passes through the pressure roller 8 and is linked to the temperature-sensitive magnetic metal pipe 7 to inductively heat the temperature-sensitive magnetic metal pipe 7. The temperature-sensitive magnetic metal pipe 7 uses an alloy whose composition is adjusted so as to have a Curie temperature at an appropriate temperature. Therefore, the temperature-sensitive magnetic metal pipe 7 is below the Curie temperature and after the Curie temperature is exceeded. The current flowing through 7 is very different. Therefore, the temperature-sensitive magnetic metal pipe 7 has a self-temperature control characteristic.
[0012]
The self-temperature control characteristic will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the main part showing a state in which an induced current flows when the temperature-sensitive magnetic metal pipe 7 is equal to or lower than the Curie temperature. If the plate thickness of the temperature-sensitive magnetic metal pipe 7 is the same as the skin thickness, most of the induced current 13 flowing in the temperature-sensitive magnetic metal pipe 7 by the high-frequency magnetic field is only in the temperature-sensitive magnetic metal pipe facing the ferrite 9. Flowing. Further, when the plate thickness of the temperature-sensitive magnetic metal pipe 7 is thinner than the skin thickness, the induced current flows through the non-magnetic material 12 beyond the temperature-sensitive magnetic metal pipe 7, and when it is thicker than that, the temperature-sensitive magnetic metal pipe 7 is temperature-sensitive even above the Curie temperature. The amount of induced current flowing through the magnetic metal pipe 7 increases. In order to shorten the time from the start of energization until the target temperature is reached, that is, the warm-up time, the heat capacity of the temperature-sensitive magnetic metal pipe may be lowered. Therefore, the thickness of the temperature-sensitive magnetic metal pipe 7 is increased from 50% of the skin thickness where the heat capacity of the temperature-sensitive magnetic metal pipe is reduced even if the self-temperature controllability is somewhat sacrificed. It is desirable to make it into the range of 200% of the skin thickness considering the above. If the frequency of the high-frequency current is 25 kHz, the skin thickness is 0.4 mm. As the frequency is increased, the skin thickness becomes thinner, so the temperature-sensitive magnetic metal pipe becomes thinner and becomes a film. The material constituting the temperature-sensitive magnetic metal pipe has an electrical resistivity of about 90 μΩ-cm, and in this state, heat is generated by the electrical resistance. FIG. 3 is a cross-sectional view of the main part showing that the induced current flows when the temperature-sensitive magnetic metal pipe 7 is equal to or higher than the Curie temperature. When the temperature-sensitive magnetic metal pipe 7 becomes higher than the Curie temperature, it loses magnetism and becomes a non-magnetic material. Then, the magnetic flux passes through the temperature-sensitive magnetic metal pipe 7 and enters the nonmagnetic material 12 having a lower electrical resistivity than the material of the temperature-sensitive magnetic metal pipe, specifically, aluminum or copper, and the induced current 14 flows therethrough. The electrical resistivity of aluminum is 2.5 μΩ-cm, the electrical resistivity of copper is 1.55 μΩ-cm, and the current cross-sectional area is large, so the amount of heat generated is extremely small even when an induced current of the same current value is passed. . Moreover, since the non-magnetic material 12 installed through the space so as not to conduct heat to the temperature-sensitive magnetic metal pipe 7 generates heat, the temperature decreases. Thus, the temperature is stable near the Curie temperature.
[0013]
FIG. 4 is a top view of the main part of the heat roller device. When the heat roller device of this embodiment is used as a copying machine, paper 15 passes through a part of the temperature-sensitive magnetic metal pipe 7 and part a. Is below the Curie temperature, and when the part b is above the Curie temperature, the part a is shown as a dotted line 16 in the temperature-sensitive magnetic metal pipe 7, and the part b is shown as a one-dot chain line 17 in the nonmagnetic material 12. Inductive current flows through. Therefore, even if the temperature is partially uneven, it works to correct it.
[0014]
(Example 2)
FIG. 5 is a cross-sectional view of a main part of the heat roller device according to the second embodiment of the present invention . A fixed temperature-sensitive magnetic metal plate 18 and a nonmagnetic material 19 having a lower electrical resistivity than the temperature-sensitive magnetic metal plate 18 are provided with a space therebetween, and a heat insulating material 20 is disposed in the space and laminated, and rotated. An induction heating coil 23 wound around a ferrite 22 fixed inside the pressure roller 21 to be arranged is arranged to constitute an induction heating unit that supplies a high frequency current from a high frequency power source 24, and the temperature-sensitive magnetic metal plate 18 is Induction heating is performed by an induction heating unit. The object to be heated is sandwiched and heated between the pressure roller 21 and the insulating film 25 supported by the temperature-sensitive magnetic metal plate 18 and rotating while sliding on the surface of the temperature-sensitive magnetic metal plate 18. In this configuration, the temperature-sensitive magnetic metal plate 18 is 0.4 mm, the same as the temperature-sensitive magnetic metal pipe of Example 1, but has a smaller heat capacity because it can be shorter than one round of the temperature-sensitive magnetic metal pipe. The insulating film 25 also has a small heat capacity density, and by making it thin, the heat capacity can be reduced and the temperature rise time can be shortened. Further, the heat insulating material 20 does not remove heat from the temperature-sensitive magnetic metal plate 18 to the nonmagnetic material 19.
[0015]
(Example 3)
FIG. 6 is a cross-sectional view of a main part of a heat roller device having an induction heating coil inside . A roller having a structure in which a nonmagnetic pipe 27 made of a material having a low electrical resistivity is laminated outside the temperature-sensitive magnetic metal pipe 26 rotates. It is heated by an induction heating coil 30 wound around a bobbin 29 provided with a ferrite 28 inside. When the induction heating coil is uniformly wound, the magnetic flux density is large at the center and small at the end, so that the end is preferably wound at a higher density than the center. The induction heating coil 30 is fixed without rotating. An electric insulator is provided outside the induction heating coil 30 so as not to cause friction due to contact with the rotating temperature-sensitive magnetic metal pipe 26 and to prevent the heat of the temperature-sensitive magnetic metal pipe 26 from being conducted. 31 is provided to guarantee a prescribed withstand voltage, and to protect the high-frequency current generating circuit 32 from being damaged by discharge from the temperature-sensitive magnetic metal pipe 26 to the induction heating coil 30 due to static electricity or lightning surge.
[0016]
In addition to the induction heating coil 30 for heating the temperature-sensitive magnetic metal pipe 26, an end induction heating coil 33 is wound around a portion opposite to the end of the temperature-sensitive magnetic metal pipe 26, and the temperature is raised. Energizes the end induction heating coil 33 to compensate the heat taken by the bearing 34 that supports the temperature-sensitive magnetic metal pipe 26 at the time of start-up so that the temperature-sensitive magnetic metal pipe 26 as a whole reaches the target temperature at the same time. This increases the temperature rise time.
[0017]
【The invention's effect】
As described above, according to the first aspect of the present invention, the temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film and the nonmagnetic material having a low electrical resistivity are arranged with a space between each other , and reduce heat capacity by Rukoto includes an induction heating section for inductively heating the temperature-magnetic metal pipe or the temperature-sensitive magnetic metal film on the outside of the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film, it is possible to speed up the rise time of temperature .
[0018]
According to the second aspect of the present invention, the induction heating coil is disposed inside the pressure roller to inductively heat the temperature-sensitive magnetic metal plate, and is supported by the temperature-sensitive magnetic metal plate and rotates to rotate. By heating the object to be heated between the film and the pressure roller, the insulating film can be thinned to reduce the heat capacity, and the temperature rise time can be shortened.
[0019]
Further, according to the invention described in claim 3 , the thickness of the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film or the temperature-sensitive magnetic metal plate is limited to the range of 50% to 200% of the skin depth, The self-temperature control characteristic can be best exhibited.
[0020]
According to the fourth aspect of the present invention, the induction heating coil for heating the temperature-sensitive magnetic metal pipe and the coil closer to the end of the temperature-sensitive magnetic metal pipe are denser than the induction heating coil. An end-induction heating coil that is rolled up is provided. When the temperature rises, the end-induction heating coil is also energized, and during the start-up, the heat taken by the bearing that supports the temperature-sensitive magnetic metal pipe is compensated. The temperature rise time can be shortened.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a heat roller device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a main portion of the heat roller device showing an induced current flowing when the temperature is equal to or lower than the Curie temperature. 3] Cross-sectional view of the main part of the heat roller device showing how the induced current flows when the temperature is equal to or higher than the Curie temperature in Example 1 [Fig. 4] Top view of the main part of the heat roller device [Fig. 5] Example 2 of the present invention FIG. 6 is a cross-sectional view of a main part of a heat roller device in Example 3 of the present invention. FIG. 7 is a perspective view of a main part of a conventional heat roller device.
7, 26 Temperature-sensitive magnetic metal pipe 8, 21 Pressure roller 10, 23, 30 Induction heating coil (induction heating section)
11 High-frequency power supply 12, 19 Non-magnetic material 18 Temperature-sensitive magnetic metal plate 20 Heat insulating material 25 Insulating film 27 Non-magnetic pipe 31 Electrical insulator 33 End induction heating coil 34 Bearing

Claims (4)

The temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film having a predetermined Curie temperature by adjusting the composition, and the inside of the temperature-sensitive magnetic metal material constituting the temperature-sensitive magnetic metal pipe or temperature-sensitive magnetic metal film. A non-magnetic material having a low resistivity is arranged with a space between each other , and the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film is used as an induction heating part for induction heating the temperature-sensitive magnetic metal pipe or the temperature-sensitive magnetic metal film. Heat roller device provided on the outside .   A temperature-sensitive magnetic metal plate and a nonmagnetic material having a lower electrical resistivity than the temperature-sensitive magnetic metal plate are laminated directly or with a space between them, and an induction heating coil is arranged inside the pressure roller. A heat roller device that heats an object to be heated between the pressure roller and an insulating film that is supported by the temperature-sensitive magnetic metal plate and rotates, and is an induction heating unit that induction-heats the temperature-sensitive magnetic metal plate . The heat roller according to any one of claims 1 to 2 , wherein the thickness of the temperature-sensitive magnetic metal pipe, the temperature-sensitive magnetic metal film, or the temperature-sensitive magnetic metal plate is in the range of 50% to 200% of the skin depth. apparatus. An induction heating coil that heats the temperature-sensitive magnetic metal pipe, and an end induction heating coil that is configured by winding the coil more densely than the induction coil at a portion facing the end of the temperature-sensitive magnetic metal pipe are provided, The heat roller device according to any one of claims 1 and 3 , wherein both of the induction heating coil and the end portion induction heating coil are energized during startup.

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