JPS62150371A - Heat pressure fixing device - Google Patents

Abstract

PURPOSE:To obtain good heat efficiency and to reduce power consumption by generating Joule's heat to a heat fixing roll made of a ferromagnetic body and heating a desired part concentrically. CONSTITUTION:An AC current is supplied to an exciting coil 6 to excite an exciting iron core 6, and then a closed magnetic path is constituted as shown by a dotted-line arrow to produce magnetic flux which penetrates a cylinder body 4 between the magnetic pole of the exciting iron core 5 and the magnetic pole of an auxiliary iron core 7. Thus, the magnetic flux which penetrates the rotating cylinder body 4 is produced to generate an eddy current at the magnetic flux penetration part of the cylinder part 4, so that the temperature of the cylinder body 4 rises owing to the Joule's heat. Namely, the cylinder body 4 is generated by the Joule's heat generated with the eddy current which flows through the cylinder body 4 itself. Consequently, the heat efficiency is good and the heating speed is increased.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a heat-pressure fixing device, particularly a heated heat-fixing roll and a pressure roll, and a heat-pressure fixing device that includes a heated heat-fixing roll and a pressure roll. In a heat-pressure fixing device for an electronic copying machine, the heat-pressure fixing device is configured to fix the toner on the paper by passing a sheet of paper onto which the toner has been transferred. The present invention also relates to a heat-pressure fixing device which includes a magnetic flux generating means for generating an eddy current in the heat fixing roll, and heats the heat fixing roll by Joule heat generated by the eddy current.

[Conventional technology]

Generally, the heat-pressure fixing device in electronic copying machines etc.
As shown in the figure, a heated heat fixing roll 1
and (2) a pressure roll 2 which rotates while pressing the heat fixing roll 1 by a drive device (not shown), and (1) between the heat fixing roll 1 and the pressure roll 2 which rotate in the direction of the arrow in the figure, for example. By applying heat and pressure to the paper 3 passing through, the toner (not shown) transferred onto the paper 3 is fixed onto the paper 3.

Conventionally, a heat fixing roll using a halogen lamp as a heat source for heating the heat fixing roll 1 is known. That is, as shown in FIG. 5, the heat fixing roll 1 is formed into a cylindrical shape, and a halogen lamp 13 is installed inside the heat fixing roll 1. It is known that the heat fixing roll 1 is heated by the above-mentioned method.

[Problem that the invention seeks to solve]

The conventional heat fixing roll using a halogen lamp as a heat source has the following problems. That is.

(i) The heat generated by the halogen lamp is not only partially lost as convection heat, but also heats the entire heat fixing roll uniformly, increasing the amount of heat radiated.

Poor thermal efficiency (high power consumption).

(ii) Since the halogen lamp has a short lifespan compared to the lifespan of the device, it must be replaced depending on the degree of performance deterioration. That is, halogen lamps must be treated as consumables.

(ii+) The structure of the heat fixing roll becomes complicated in order to make it possible to replace the halogen lamp.

These are the problems.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems, and therefore, the heat-pressure fixing device of the present invention includes a heated heat-fixing roll and a device that presses the heat-fixing roll. Thermal pressure in an electronic copying machine is equipped with a pressure roll and is configured to fix the toner on the paper by passing the paper to which the toner has been transferred between the heat fixing roll and the pressure roll. In the fixing device, the heat fixing roll is formed in a cylindrical shape using a ferromagnetic material, and an excitation coil is wound around one of the inside and outside of the cylindrical body of the heat fixing roll formed in the cylindrical shape. A rotating excitation iron core is provided, and an auxiliary iron core forming a closed magnetic path with respect to the excitation iron core is provided on the other hand, and by supplying an alternating current to the excitation coil, a magnetic flux passing through the cylindrical body is generated, and the magnetic flux is The cylindrical body is characterized in that the cylindrical body is heated by Joule heat generated by eddy current generated in the cylindrical body.

〔Example〕

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG.
1(B) is a sectional view, and FIG. 1(B) is a perspective view of the excitation core and auxiliary core in FIG. 1(A).

Further, FIG. 2 is a configuration diagram of another embodiment of the present invention, FIG. 3 is a perspective view of an excitation core and an auxiliary core in still another embodiment of the present invention, and FIG. 4 is a diagram of still another embodiment of the present invention. The perspective view of the excitation core in one Example is shown.

First, the basic principle of the present invention will be explained with reference to FIG.

Note that reference numeral 1 in Figure 2 is a heat fixing roll made of ferromagnetic material and formed into a cylindrical shape, and 2 is a pressure roll that presses the heat fixing roll 1 by a drive device (not shown). For example, one that rotates in the direction of the arrow shown in the figure, 3
Reference numeral 4 indicates a paper onto which toner (not shown) has been transferred; 4 is a cylinder; 5 is an excitation core; 6 is an excitation coil; 7 is an auxiliary core; the cylindrical body 4 is connected to the magnetic pole of the excitation core 5
This represents a device that has magnetic poles facing each other with a distance between them to form a closed magnetic circuit.

In FIG. 1, an excitation core 5 having an excitation coil 6 wound inside a cylindrical body 4 of a heat fixing roll 1 is shown.

The magnetic pole of the excitation iron core 5 is placed so as to face the inner circumferential surface of the cylindrical body 4. The excitation core 5 is.

As shown in FIG. 1(B), it has a so-called U-shaped cross-sectional shape, and has a length dimension corresponding to the length of the cylindrical body 4 in the axial direction.

As shown in FIG. 1(B), an auxiliary iron core is provided with a magnetic pole corresponding to the magnetic pole of the excitation iron core 5 and has a U-shaped cross section and has the same length as the excitation iron core 5. 7 is installed so that the magnetic pole of the auxiliary core 7 faces the magnetic pole of the excitation core 5 with the cylindrical body 4 in between.

In the heat fixing roll l (shown in FIG. 1A) configured as described above, an alternating current is supplied to the excitation coil 6 to excite the excitation core 5.

When the exciting iron core 5 is excited, as shown in FIG.
A closed magnetic path as shown by the dotted arrow in is constructed, and a magnetic flux passing through the cylindrical body 4 is generated between the magnetic pole of the exciting iron core 5 and the magnetic pole of the auxiliary iron core 7. In addition,
Although the direction of the dotted line arrow shown in FIG. 1(A) represents only one direction, it goes without saying that the direction is reversed in accordance with the cycle of the alternating current supplied to the excitation coil 6.

As explained above, when a magnetic flux is generated that penetrates the cylindrical body 4 that rotates once, an eddy current is generated in the magnetic flux penetrating portion of the cylindrical body 4, and the temperature of the cylindrical body 4 increases due to Joule heat caused by the eddy current. do. That is, in the present invention, the cylindrical body 4 is heated not by an external heat source (for example, the halogen lamp 13 shown in FIG. 5), but by Joule heat generated by the eddy current flowing through the cylindrical body 4 itself. be exposed. Therefore, not only is the thermal efficiency good, but the heating rate is also fast. Furthermore, by controlling the current value of the excitation coil 6, temperature control can be easily performed.

Furthermore, the installation positions of the excitation core 5 and the auxiliary core 7 in the present invention will be explained. It is desirable that the installation position be as close as possible to the position where heat-pressure fixing is performed (thermal fixing position). That is, in the present invention, as shown in FIG. 1(A).

Assuming that the rotational direction of the heat fixing roll 1 is in the direction of the arrow shown in the figure, it is set as close as possible to the heat fixing position in the direction opposite to the direction of the arrow in the figure.

Therefore, in the present invention, since the time from when the heated portion of the cylindrical body 4 of the heat fixing roll 1 is heated until it reaches the heat fixing position is shortened, it is possible to reduce heat loss during that time. can.

The embodiment shown in FIG. 1 has been described above, and the basic principle of the present invention has been explained in relation to the embodiment shown in FIG. This example is also based on the basic principle of the invention described above and has basically the same structure and effect as the embodiment shown in FIG.

In the embodiment shown in FIG. 2, an excitation core 5 around which an excitation coil 6 is wound is installed outside a cylindrical body 4, and an auxiliary iron core 7 is installed inside. In addition.

The excitation core 5 and the auxiliary core 7 in the embodiment shown in FIG. 2
The excitation core 5 and the auxiliary core 7 in the embodiment shown in FIG.
It has the same configuration as .

FIG. 3 shows a perspective view of an excitation core and an auxiliary core in still another embodiment of the present invention. The excitation core 8 and the auxiliary core 10 in this embodiment are as follows.

As shown, it is formed into a fork shape. The plurality of legs of the excitation core 8 are provided with independent excitation coils 9. ... is wound around.

And the excitation coil 9.9. ... is supplied with alternating current so that each leg of the excitation core 8 is alternately excited with opposite polarity to prevent leakage of magnetic flux to the outside. In this embodiment, the excitation core 8 may be installed inside the second cylindrical body 4 and the auxiliary core IO may be installed outside the second cylindrical body 4, as in the embodiment shown in FIG. Similarly to the illustrated embodiment, the excitation core 8 may be installed outside the cylindrical body 4, and the auxiliary core 10 may be installed inside.

FIG. 4 shows a perspective view of an excitation core 11 used in yet another embodiment of the present invention. Fig. 4 Exciting core 11 shown in Figure 4
It may be considered that the excitation core 5 used in the embodiments shown in FIGS. 1 and 2 is divided in the longitudinal direction. And each exciting core 11.11. ..., respectively independent excitation coils 12.12. ... is wound around. 9 Although not shown in the drawings, the auxiliary core used in this embodiment is also the same as the excitation core 11, so to speak, the auxiliary core 7 used in the embodiments shown in FIGS. 1 and 2 is divided in the longitudinal direction. It's good to think so. In this embodiment, a plurality of excitation cores 11 and auxiliary cores (not shown) are arranged in pairs inside and outside the axial direction of one cylindrical body 4. Note that the arranged excitation cores 11.11.・
An alternating current is supplied to the excitation coils 12, 12, . . . so that the adjacent excitation cores 11, 11, . The magnetic flux is made small.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to intensively heat a desired portion of the heat fixing roll, resulting in good thermal efficiency and low power consumption. In addition, by controlling the current value supplied to the excitation coil,
Temperature control can be performed accurately and easily. Furthermore, conventional methods using halogen lamps as heat sources have had undesirable problems such as the need to replace the lamps and the need for large capacity power supplies due to the large starting current that flows when the halogen lamps are turned on. can be solved all at once.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG.
1(B) is a sectional view, and FIG. 1(B) is a perspective view of the excitation core and auxiliary core in FIG. 1(A). Further, FIG. 2 is a configuration diagram of another embodiment of the present invention, FIG. 3 is a perspective view of an excitation core and an auxiliary core in still another embodiment of the present invention, and FIG. 4 is a diagram of still another embodiment of the present invention. The perspective view of the excitation core in one Example is shown. In the figure, 1 is a heat fixing roll, and 2 is a pressure roll. 3 is paper, 4 is a cylindrical body, 5.8 and 11 are exciting iron cores,
6.9 and 12 represent excitation coils, and 7 and 10 represent auxiliary iron cores. Patent applicant: Patent attorney representing Alps Electric Co., Ltd.
Mori 1) Hiroshi (3 others) v, 412] $ 5 Figure

Claims (1)

[Claims] A heated heat fixing roll and a pressure roll provided to press the heat fixing roll are provided, and the paper having the toner transferred thereon is passed between the heat fixing roll and the pressure roll. In a heat-pressure fixing device in an electronic copying machine configured to heat-pressure fix the toner to the paper, the heat-fixing roll is formed of a ferromagnetic material and has a cylindrical shape. The cylindrical body of the heat fixing roll is provided with an excitation core around which an excitation coil is wound on either the inside or the outside, and an auxiliary iron core forming a closed magnetic path with respect to the excitation core on the other side, and the excitation coil A magnetic flux passing through the cylindrical body is generated by supplying an alternating current to the cylindrical body, and the cylindrical body is heated by Joule heat generated by an eddy current generated in the cylindrical body by the magnetic flux. A heat-pressure fixing device featuring: