JP4847131B2 - Heating roll device - Google Patents

Description

  The present invention relates to a heating roll apparatus, and more particularly to a heating roll apparatus that can heat a heating roll with a uniform temperature distribution and has little leakage magnetic flux and excellent heating efficiency.

2. Description of the Related Art Conventionally, there has been known a heating roll device in which an excitation coil is installed in an internal space of a cylindrical heating roll, and an induction current is caused to flow through the heating roll by the excitation coil so that the heating roll is heated to a high temperature. Examples of the excitation coil include a loop coil having a coil axis orthogonal to the axial direction of the heating roll (see, for example, Patent Documents 1 and 2), and a spiral coil having a turning axis in the axial direction of the heating roll (for example, (See Patent Document 3).
JP 2000-150131 A JP 2003-215594 A JP 2003-330291 A

The conventional electromagnetic induction heating type heating roll device has a configuration in which the entire exciting coil is accommodated in the internal space of a cylindrical heating roll.
However, this configuration has a problem that the temperature distribution in the circumferential direction and the length direction of the heating roll is biased and a problem that the leakage magnetic flux is large.
SUMMARY OF THE INVENTION An object of the present invention is to provide a heating roll device that can heat a heating roll with a uniform temperature distribution and has little leakage magnetic flux and excellent heating efficiency.

In a first aspect, the present invention provides a cylindrical rotating heating roll, a bobbin inserted into the heating roll and having a circumferential surface concentric with the heating roll and not rotating, and a circumference of the bobbin An excitation coil comprising a plurality of inner conductors fixed at a uniform density on the surface and extending in the axial direction of the heating roll, and a plurality of outer conductors arranged in an outer space of the heating roll and serving as a return path for the plurality of inner conductors comprising the door, the plurality of outer side conductor to provide a heating roll and wherein the distributed concavely when viewed from the heating roll side.
In the heating roll device according to the first aspect, since a plurality of inner conductors are fixed at a uniform density on the circumferential surface of the bobbin, local magnetic flux saturation does not occur, and the heating roll is heated with a uniform temperature distribution. I can do it. Moreover, since the heating roll exists in the coil, the leakage magnetic flux is reduced, the magnetic flux density is increased, and the heating efficiency can be improved. Furthermore, for positioning are distributed to a concave shape when viewed a plurality of outer side lead from the heating roll side, the difference in magnetic flux density at the magnetic flux density and the concave edge of the concave central decreases, a uniform temperature distribution The heating roll can be heated.

In a second aspect, the present invention provides the heating roll device according to the first aspect, wherein the concave surface is a circumferential surface.
Above by the heating roll device to the second aspect, it is possible to equalize the distance from the outer side conductors distributed concave to the outer surface of the heating roll.

In a third aspect, the present invention provides a heating roll apparatus according to the second aspect, the distance from the outer side conductor to the outer peripheral surface of the heating roll and Lo, the inner circumference of the heating roller from the inner side conductor Provided is a heating roll device characterized in that Lo = Li, where Li is the distance to the surface.
Above by the heating roll apparatus a third aspect, since the center heating roll of outer side conductor and the inner side conductor is located, the magnetic flux density is high, it is possible to improve the heating efficiency.

In a fourth aspect, the present invention provides a heating roll apparatus according to the first aspect, the edge of the concave surface than the distance Lc from the outer side conductor located in the center of the concave to the outer peripheral surface of the heating roll to provide a heating roll and wherein the person from the outer side conductor of the distance Le to the outer peripheral surface of the heating roll is small to.
In the heating roll device according to the fourth aspect, the magnetic flux density at the end of the concave surface can be raised more than the magnetic flux density at the center of the concave surface than when the concave surface is a circumferential surface.

In a fifth aspect, the present invention provides the heating roller apparatus according to the fourth one aspect from the first, to provide a heating roll system, characterized in that the outer side conductors adjacent in close contact .
In the heating roll apparatus of the fifth aspect is comprised of a concave surface with a plurality of outer side lead easily to shape retention.

  According to the heating roll device of the present invention, it is possible to heat the heating roll with a uniform temperature distribution, and there is little leakage magnetic flux, and heating efficiency can be improved.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings. Note that the present invention is not limited thereby.

FIG. 1 is a right side view illustrating the heating roll device 10 according to the first embodiment. FIG. 2 is a front view of the same.
This heating roll device 10 has a cylindrical heating roll 1 that is supported so as to be rotated by a rotary support tool 2, a circumferential surface that is inserted into the heating roll 1 and concentric with the heating roll 1, and is fixedly supported. A bobbin 3 supported so as not to rotate by the tool 4, and a plurality of inner conductors 5 a and heating rolls 1 fixed to the circumferential surface of the bobbin 3 with equal density and extending in the axial direction (longitudinal direction) of the heating roll 1. And an exciting coil 5 composed of an outer conductor 5b which is disposed in the outer space and serves as a return path for the plurality of inner conductors 5a.
There is a gap 7 between the heating roll 1 and the bobbin 3.

A plurality of outer side conductor 5b is viewed from the heating roll 1 side are distributed in close contact with each other in the concave. This concave surface is a part of the circumferential surface of the virtual cylinder C concentric with the heating roll 1. Accordingly, the distance from the outer side conductor 5b to the outer peripheral surface of the heating roll 1 is all turned Lo.
Further, when the distance from the inner side conductors 5a to the inner peripheral surface of the heating roll 1 and Li, has become Lo = Li.

  The exciting coil 5 is a loop coil having a coil axis orthogonal to the axial direction of the heating roll 1. By passing a high frequency (for example, 20 kHz to 50 kHz) current through the exciting coil 5, an induced current flows through the heating roll 1 to generate heat, resulting in a high temperature (for example, 200 ° C.).

  The heat transfer belt 6 is an endless belt that transfers the heat of the heating roll 1 that has reached a high temperature to a fixing roll of a fixing device of an image forming apparatus such as a printer or a copying machine.

The heating roll 1 is made of a ferromagnetic material (for example, iron) that is easily heated by electromagnetic induction.
The bobbin 3 is made of a heat-resistant material (for example, a ceramic having heat resistance, a glass baked product, a liquid crystal polymer that is a heat-resistant resin, or a phenol resin).
The inner conducting wire 5a and the outer conducting wire 5b are conducting wires (for example, magnet wires) through which a high-frequency current easily flows.

FIG. 3 is a plan view of the bobbin 3 to which the inner conductor 3a is fixed.
After inserting the bobbin 3 into the heating roll 1, the exciting coil 5 can be configured by connecting the inner conductor 3a to the outer conductor 5b.

In the heating roll device 1, since the plurality of inner conductors 5 a are fixed to the circumferential surface of the bobbin 3 with an equal density, local magnetic flux saturation does not occur, and the temperature distribution is uniform over a wide range of the heating roll 1. Can generate heat. Moreover, since the heating roll 1 exists inside the exciting coil 5, the leakage magnetic flux can be reduced and the heating efficiency can be improved. Further, since the leakage magnetic flux can be reduced, the core for the magnetic shield can be reduced, and the configuration and cost can be reduced. Furthermore, for positioning are distributed to a concave shape when viewed a plurality of outer side conductor 5b from the heating roll 1 side, the difference in magnetic flux density at the magnetic flux density and the concave edge of the concave central decreases, uniform temperature The heating roll 1 can be heated by distribution.

FIG. 4 is a right side view illustrating the heating roll device 20 according to the second embodiment.
The heating roll 20 has substantially the same structure as the heating roll apparatus 10 according to the first embodiment, the outer side conductor located in the center of the concave surface is on the circumferential surface of the heating roll 1 and the concentric virtual cylinder Cc the relative outer side conductors located on the concave surface of the edge is on the circumferential surface of the imaginary cylinder Ce smaller radius of the imaginary cylinder Cc. In other words, towards the distance Le from the outer side conductors located on the concave surface of the end than the distance Lc from the outer side conductor located in the center of the concave to the outer peripheral surface of the heating roll 1 to the outer peripheral surface of the heating roll 1 is decreased Yes. Note that Lc = Li.

  According to the heating roll device 20 according to the second embodiment, the magnetic flux density at the end of the concave surface can be raised with respect to the magnetic flux density at the center of the concave surface as compared with the first embodiment.

  The heating roll device of the present invention can be used as a heat source of a fixing device of an image forming apparatus such as a printer or a copying machine.

It is a right view which shows the heating roll apparatus concerning Example 1. FIG. It is a front view which shows the heating roll apparatus concerning Example 1. FIG. It is a top view of the bobbin 3 which fixed the inner side conducting wire 3a. It is a right view which shows the heating roll apparatus concerning Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating roll 2 Rotating support 3 Bobbin 4 Fixed support 5 Excitation coil 5a Inner conducting wire 5b Outer conducting wire 6 Heat transfer belt 7 Space | gap 10,20 Heating roll apparatus

Claims (5)

A cylindrical rotating heating roll; a bobbin which is inserted into the heating roll and has a circumferential surface concentric with the heating roll and which does not rotate; and is fixed to the circumferential surface of the bobbin with an equal density and comprising an excitation coil consisting of a plurality of inner conductors and a plurality of outer conductors serving as the return path of the disposed outside space of the heating roll and the plurality of inner conductors extending in the axial direction of the heating roll, the plurality of outer side The heating roll device characterized in that the conducting wire is distributed in a concave shape when viewed from the heating roll side. The heating roll device according to claim 1, wherein the concave surface is a circumferential surface. In the heating roll apparatus according to claim 2, when the distance from the outer side conductor to the outer peripheral surface of the heating roll and Lo, a distance from the inner side conductor to the inner peripheral surface of the heating roll and Li, A heating roll device, wherein Lo = Li. In the heating roll apparatus according to claim 1, the outer periphery of the heating roll from the outer side conductors located on said concave edge than the distance Lc from the outer side conductor located in the center of the concave to the outer peripheral surface of the heating roll A heating roll device characterized in that the distance Le to the surface is smaller. In the heating roll apparatus according to any one of claims 1 to 4, the heating roll apparatus, characterized in that the outer side conductors adjacent in close contact.

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