JP2001242727A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating(IH) type fixing device capable of obtaining desired temperature distribution orientation by eliminating temperature irregularity in the longitudinal direction of a roller. SOLUTION: A coil 11 spirally wound round the shaft of a cylindrical heat roller 1 formed of conductive material such as iron or nickel is attached to the inside of the roller 1 so that both ends thereof may project to the outside from both ends of the roller 1. Thus, the entering point of magnetic flux is nearly uniformized all over the area of the roller 1, and the temperature irregularity in the longitudinal direction of the roller 1 is reduced. The same effect is expected by constituting the outer periphery of the coil proximately to the inner peripheral surface of the heat roller, attaching a ring-like magnetic body to both ends of the coil, or dividing the coil into plural in the shaft direction of the heat roller and arraying the divided coils in a direction where the magnetic directions of the respective adjacent coils are made revere to each other. It is more effective if they are combined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating type fixing device in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. , And an image forming apparatus equipped with the same.

[0002]

2. Description of the Related Art As a fixing device mounted on an image forming apparatus such as a copying machine, a facsimile, a printer, etc., a fixing roller for heat-melting toner on a transfer sheet, and a transfer roller pressed against the fixing roller to sandwich the transfer sheet. Most commonly, the pressure roller includes a pressure roller. Here, as the fixing roller, conventionally, a heating element such as a halogen lamp is disposed inside the roller, and the surface of the roller is heated by radiant heat from the heating element. However, such a fixing roller has
Since there are several problems such as a relatively long time required for the roller surface to reach an appropriate temperature and a large energy loss, an induction heating method (hereinafter referred to as an IH method) has been proposed as a solution to these problems. Fusing rollers have been proposed. The IH type fixing roller has a configuration in which a coil wound spirally in the axial direction, for example, is disposed inside a roller made of a metal conductor, and a high-frequency current flows through the coil to generate a high-frequency current. An induced eddy current is generated in the roller by a magnetic field, and the roller itself generates Joule heat by the skin resistance of the roller itself. With such a configuration, the temperature can be raised in a shorter time than indirect heating from a halogen lamp or the like.
Further, it is possible to reduce energy loss corresponding to heat generation, light leakage, and the like in portions other than the rollers.

[0003]

In such an IH type fixing device, when a coil is wound around the axis of the roller 52 as shown in FIG. It becomes non-uniform (in the axial direction), and the magnetic flux is coarse at both ends of the roller 52 and dense at the center. Since the heat generated by the IH method is proportional to the density of the penetrating magnetic flux, the conventional fixing roller in which the coil is wound around the roller axis tends to cause temperature unevenness in the longitudinal direction of the roller.
There is a problem that it is difficult to obtain a desired temperature distribution orientation.
In addition, in order to eliminate temperature unevenness and the like and obtain a desired temperature distribution orientation in the longitudinal direction of the roller, there is known a method in which the pitch of a coil wound around the roller axis is changed depending on a location to provide a winding density. However, winding a coil on a bobbin while changing the pitch in this way is extremely difficult, whether mechanical or manual, and is not practical. In particular, in a portion where the coil wire is sparsely wound, a deviation of the coil wire or the like occurs, so that it is extremely difficult to accurately wind the coil wire at a desired pitch. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an induction heating type fixing device capable of eliminating a temperature unevenness in a longitudinal direction of a roller and obtaining a desired temperature distribution orientation. It is to provide.

[0004]

In order to achieve the above object, a first invention (Claim 1) comprises a cylindrical heat roller formed of a conductive material inside a heat roller around the axis of the heat roller. An induction heating type fixing device having a wound coil disposed therein, wherein the coil is formed so as to protrude outward from both ends of an image area of the heat roller. It is configured as a device. With such a configuration, the entry point of the magnetic flux in the image area of the heat roller is made substantially uniform, and temperature unevenness in the longitudinal direction of the heat roller can be reduced.

According to a second aspect of the present invention, there is provided an induction heating apparatus in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. In the fixing device of the system, the outer periphery of the coil is configured to be close to the inner peripheral surface of the heat roller, so that the fixing device is configured. Specifically, it is desirable that the heat roller inner diameter d1, the coil outer diameter d2, and the protrusion amount a of the coil end from the image area satisfy d1−d2 ≦ a. With such a configuration, the entry point of the magnetic flux to the heat roller is made substantially uniform at least within the range of the length of the coil, so that temperature unevenness in the longitudinal direction of the heat roller 1 can be reduced.

According to a third aspect of the present invention, there is provided an induction motor in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. In the heating type fixing device, a ring-shaped magnetic body is attached to both ends of the coil, so that the fixing device is configured. With this configuration, the magnetic flux generated by the coil is guided by the ring-shaped magnetic body and enters the heat roller, so that the entry point of the magnetic flux to the heat roller is substantially uniform at least within the length of the coil. Thus, temperature unevenness in the longitudinal direction of the heat roller can be reduced. Further, if the outer diameter of the ring-shaped magnetic body is made larger than the outer diameter of the coil, there is also an effect of preventing contact with the coil due to bending of the heat roller during fixing pressurization. still,
By combining the configuration of the third aspect with the first and second aspects, it is possible to further enhance the effect of reducing the temperature unevenness in the longitudinal direction of the heat roller by a synergistic effect thereof. .

According to a fourth aspect of the present invention, there is provided an induction heating apparatus comprising a cylindrical heat roller formed of a conductive material and a coil wound around an axis of the heat roller. In a heating type fixing device, the coil is divided into a plurality in the axial direction of the heat roller, and the coils are arranged so that the magnetic directions of adjacent coils are opposite to each other. Have been. With such a configuration, since the polarity is repelled at the opposing portions of the coils, the magnetic flux entering the heat roller can be made uniform, and the temperature unevenness in the longitudinal direction of the heat roller can be reduced. It should be noted that the configuration of the fourth aspect of the invention can be combined with the first to third aspects of the invention to further enhance the effect of reducing the temperature unevenness in the longitudinal direction of the heat roller by a synergistic effect thereof. 6).

In the first to fourth aspects of the present invention, if the coil is further configured to be detachable in a state of being divided in the longitudinal direction, the space in the pull-out direction can be reduced when exchanging the coil. The restrictions on the installation location and the like are reduced, and the replacement work is facilitated (claim 8). Also,
As mentioned above, multiple types of coils that can be split and removed are prepared by changing the winding density and length, and modularized.
If several coils are used in combination according to the roller length and the temperature orientation of each model, it is not necessary to prepare individual coils for each model having different specifications, which is convenient. In this case, coils with different winding densities are connected in order to adjust the temperature orientation. However, since the winding densities are constant in each coil, compared to the case where the winding densities are provided with a single coil. And much easier to manufacture.

According to a fifth aspect of the present invention, there is provided an induction motor in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. The heating type fixing device is configured as a fixing device characterized in that the diameter of the coil is made non-uniform in the axial direction. With such a configuration, it is possible to adjust the temperature distribution orientation of the heat roller more easily than, for example, a method in which the winding density of the coil is varied.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and examples of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. The following embodiments and examples are examples embodying the present invention, and do not limit the technical scope of the present invention. Here, FIG. 1 is a schematic configuration diagram of a fixing roller Z1 according to the first embodiment, FIG. 2 is a schematic configuration diagram of a fixing roller Z2 according to the second embodiment, and FIG.
FIG. 4 is a schematic configuration diagram of a fixing roller Z4 according to a fourth embodiment, FIG. 5 is a schematic configuration diagram of a fixing roller Z5 according to a fifth embodiment, and FIG. FIG. 7 is a diagram showing an example of a detachable configuration, FIG. 7 is a diagram showing an example of two coils having different winding densities, FIG. 8 is a diagram showing an example of three coils having different lengths, and FIG. FIG. 15 is a schematic configuration diagram of a fixing roller Z5 according to a seventh embodiment.

(Embodiment 1: Corresponding to Claim 1) An IH type fixing roller Z1 according to Embodiment 1 is a copier,
It is mounted on an image forming apparatus such as a printer or a facsimile. As shown in FIG. 1, a cylindrical heat roller 1 made of a conductive material such as iron or nickel is provided inside a cylindrical heat roller 1 around the axis of the heat roller 1. Spirally wound coil 11
Are arranged. Here, the coil 1
1 is formed to be longer than the heat roller 1,
The heat roller 1 is attached so that both ends protrude outward from both ends of the heat roller 1. Accordingly, the entry point of the magnetic flux is substantially uniform in the entire area of the heat roller 1, and the temperature unevenness in the longitudinal direction of the heat roller 1 can be reduced. Since the temperature of the heat roller 1 needs to be uniform at least in the image area, the length of the coil 11 does not necessarily need to be longer than that of the heat roller 1, and is at least longer than the image area of the heat roller 1. I just need.

(Embodiment 2: Corresponding to Claim 2) As shown in FIG. 2, an IH type fixing roller Z2 according to Embodiment 2 has a cylindrical shape formed of a conductive material such as iron or nickel. A coil 12 spirally wound around the axis of the heat roller 1 is disposed inside the heat roller 1. Here, the coil 12 is formed so as to have an outer diameter slightly smaller than the inner diameter of the heat roller 1, and is mounted so that its outer periphery is close to the inner peripheral surface of the heat roller 1. Specifically, assuming that the inner diameter of the heat roller 1 is d1, the outer diameter of the coil 12 is d2, and the amount of protrusion of the coil end from the image area is a, the outer circumference of the coil is adjusted to the extent that d1−d2 ≦ a. It is desirable to make it close to the inner peripheral surface. As a result, the entry point of the magnetic flux to the heat roller 1 is made substantially uniform at least within the range of the length of the coil 12, so that the heat roller 1
Temperature unevenness in the longitudinal direction can be reduced.

(Embodiment 3: Corresponding to Claim 5) An IH type fixing roller Z3 according to Embodiment 3 is formed of a conductive material such as iron or nickel as shown in FIG. The heat roller 1 is mounted inside a cylindrical heat roller 1 whose both ends are rotatably supported by bearings or the like.
The coil 13 spirally wound around the axis is fixedly supported. At both ends of the coil 13, caps 21 (an example of a ring-shaped magnetic material) on a ring made of a material (ferrite or the like) through which magnetic flux easily passes are attached. The cap 21 is formed such that its outer peripheral surface is close to the inner peripheral surface of the heat roller 1. Thereby, the magnetic flux generated by the coil 13 is guided by the cap 21 and enters the heat roller 1, so that the entry point of the magnetic flux to the heat roller 1 is made substantially uniform at least within the length of the coil 12. Thus, temperature unevenness in the longitudinal direction of the heat roller 1 can be reduced. Also, the cap 21 has
There is also an effect of preventing contact with the coil 13 due to bending of the heat roller 1 during fixing pressurization. In this case, it is necessary to use a material having a sliding property for the cap 21.

(Embodiment 4: Corresponding to Claim 7) As shown in FIG. 4, an IH type fixing roller Z4 according to Embodiment 4 has a cylindrical shape formed of a conductive material such as iron or nickel. Inside the heat roller 1, a plurality of coils (three in FIG. 4) arranged spirally around the axis of the heat roller 1 in the axial direction of the heat roller 1 are arranged. In each of the coils 14, the magnetic directions of the adjacent coils are opposite to each other, for example, by changing the winding directions of the coils. As a result, since the polarity is repelled at the opposing portions of the coils, the magnetic flux entering the heat roller 1 can be made uniform, and the temperature unevenness in the longitudinal direction of the heat roller 1 can be reduced.

(Fifth Embodiment: Corresponding to Claims 3, 4, and 6) By combining two or more of the above-described first to fourth embodiments, the temperature unevenness in the longitudinal direction of the heat roller 1 can be reduced by a synergistic effect. It is possible to further enhance the reduction effect. As an example, FIG. 5 shows a fixing roller Z5 (corresponding to claim 6) in which the third and fourth embodiments are combined. The fixing roller Z5 includes a coil 14 spirally wound around the axis of the heat roller 1 inside the cylindrical heat roller 1.
Are plural in the axial direction of the heat roller 1 (three in FIG. 5)
The arrangement is arranged. In addition, each coil 1
4. By changing the winding direction of the coil,
The magnetic directions of the adjacent coils are opposite to each other. Further, a cap 21 (an example of a ring-shaped magnetic material) on a ring formed of a material (ferrite or the like) through which magnetic flux can easily pass is attached between and between the coils 14. Thereby, the magnetic flux entering the heat roller 1 can be more effectively made uniform by the synergistic effect of the magnetic flux induction effect by the cap 21 and the coils 14 divided into a plurality and arranged so that the polarities repel each other. As a result, temperature unevenness in the longitudinal direction of the heat roller 1 can be further reduced.

(Sixth Embodiment: Corresponding to Claims 8 and 9) Regarding the fixing rollers according to the first to fifth embodiments, for example, as shown in FIG. 6, the coils are divided in the longitudinal direction. If it is configured to be detachable, the space in the pull-out direction can be reduced when replacing the coil, so that the restriction on the installation location of the device and the like can be reduced, and the replacement operation can be facilitated. Here, the connection of each of the divided coils (the reference numeral 15 is used here) is made, for example, by connecting the connectors 3 formed at both ends of the bobbin 31 around which the coils 15 are wound.
What is necessary is just to perform via 1a. Also, as described above, a plurality of types of coils that can be divided and detached are prepared by changing the winding density and length (see FIGS. 7 and 8) and modularized so as to match the roller length and temperature orientation of each model. By using several coils in combination, there is no need to prepare individual coils for models with different specifications.
It is convenient. For example, if the length of the coil is L, 2L,
A total of six types of coils are prepared with three types of 3L and different winding densities in two stages (sparse and dense) for each length. For example, in the case of a model having a heat roller length of 4 L, if it is desired to increase the temperature at the center of the roller, a coil with a length of 2 L and a coil with a length of L are sparsely disposed at both ends. I just need. In this case, coils having different winding densities are connected as described above in order to adjust the temperature orientation. However, since the winding densities are constant in each coil, the winding densities of one coil are adjusted. It is much easier to manufacture than in the case where it is provided.

(Embodiment 7: Corresponding to Claim 10) As shown in FIG. 9, an IH type fixing roller Z5 according to Embodiment 5 has a cylindrical shape formed of a conductive material such as iron or nickel. Inside the heat roller 1, the heat roller 1
A coil 16 spirally wound around the axis is disposed. Here, the bobbin 32 around which the coil 16 is wound,
The central portion 32a and both end portions 32b are formed to have different diameters (here, the central portion 32a has a larger diameter than the both end portions 32b). Therefore, the coil 16 wound around the bobbin 32 at an equal pitch also has a larger diameter at the center than at both ends. Here, since a stronger magnetic field is obtained as the coil diameter is larger, the temperature of the heat roller in that portion becomes relatively higher. Therefore, the fixing roller Z shown in FIG.
In the case of No. 5, a temperature distribution orientation is obtained such that the center of the heat roller 1 has a higher temperature than both ends. At this time,
Since the winding density of the coil may be constant, the winding operation of the coil is much easier and more reliable than a method in which the winding density of the coil is varied. Thus, by making the diameter of the coil non-uniform in the axial direction, it is possible to easily adjust the temperature distribution orientation of the heat roller. Here, in order to obtain a temperature distribution orientation such that the center of the heat roller 1 is higher than both ends, the bobbin shape as shown in FIG. 9 is used. You can decide freely based on the Further, the diameter of the bobbin is not limited to one that is changed discontinuously as shown in FIG. 9, but may be changed continuously.

[0018]

As described above, according to the first invention (claim 1), a coil wound around the axis of the heat roller is provided inside a cylindrical heat roller formed of a conductive material. In the induction heating type fixing device arranged,
Since the coil is formed as a fixing device having a length protruding outward from both ends of the image area of the heat roller, the entry point of the magnetic flux in the image area of the heat roller Is made substantially uniform, and temperature unevenness in the longitudinal direction of the heat roller can be reduced.

According to a second aspect of the present invention, there is provided an induction heating apparatus in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. In the fixing device of the system, the outer periphery of the coil is close to the inner peripheral surface of the heat roller (specifically, the inner diameter d1 of the heat roller, the outer diameter d of the coil
2, and the protrusion amount a of the coil end from the image area
Is desirably set so as to satisfy d1−d2 ≦ a), so that the entry point of the magnetic flux to the heat roller is at least the length of the coil. Because it is almost uniform within the range,
Temperature unevenness in the longitudinal direction of the heat roller 1 can be reduced.

According to a third aspect of the present invention, a coil is formed around a shaft of the heat roller inside a cylindrical heat roller formed of a conductive material. In the heating type fixing device, since a ring-shaped magnetic material is attached to both ends of the coil, the magnetic flux generated by the coil is applied to the ring-shaped magnetic material. The heat flux is guided to enter the heat roller, and the entry point of the magnetic flux to the heat roller is made substantially uniform at least within the range of the length of the coil, so that the temperature unevenness in the longitudinal direction of the heat roller can be reduced. Further, if the outer diameter of the ring-shaped magnetic body is made larger than the outer diameter of the coil, there is also an effect of preventing contact with the coil due to bending of the heat roller during fixing pressurization.

Further, according to a fourth aspect of the present invention, there is provided an induction motor in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. In a heating type fixing device, the coil is divided into a plurality in the axial direction of the heat roller, and the coils are arranged so that the magnetic directions of adjacent coils are opposite to each other. Therefore, the magnetic flux entering the heat roller can be made uniform, and the temperature unevenness in the longitudinal direction of the heat roller can be reduced.

Further, by combining two or more of the first to fourth inventions, it is possible to further enhance the effect of reducing the temperature unevenness in the longitudinal direction of the heat roller by a synergistic effect. 4,6).

In the first to fourth aspects of the present invention, if the coil is further configured to be detachable in a state of being divided in the longitudinal direction, the space in the pull-out direction can be reduced when the coil is replaced or the like. The restrictions on the installation location and the like are reduced, and the replacement work is facilitated (claim 8). Also,
As mentioned above, multiple types of coils that can be split and removed are prepared by changing the winding density and length, and modularized.
If several coils are used in combination according to the roller length and the temperature orientation of each model, it is not necessary to prepare individual coils for each model having different specifications, which is convenient. In this case, coils with different winding densities are connected in order to adjust the temperature orientation. However, since the winding densities are constant in each coil, compared to the case where the winding densities are provided with a single coil. And much easier to manufacture.

According to a fifth aspect of the present invention, there is provided an induction motor comprising a cylindrical heat roller formed of a conductive material and a coil wound around an axis of the heat roller. In a heating type fixing device, the diameter of the coil is made non-uniform in the axial direction, so that the heat roller can be easily heated compared to a method in which the winding density of the coil is varied. Can be adjusted.

[Brief description of the drawings]

FIG. 1 shows a fixing roller Z1 according to a first embodiment of the present invention.
FIG.

FIG. 2 shows a fixing roller Z2 according to a second embodiment of the present invention.
FIG.

FIG. 3 shows a fixing roller Z3 according to a third embodiment of the present invention.
FIG.

FIG. 4 shows a fixing roller Z4 according to a fourth embodiment of the present invention.
FIG.

FIG. 5 shows a fixing roller Z5 according to a fifth embodiment of the present invention.
FIG.

FIG. 6 is a diagram showing an example of a configuration in which a coil can be divided and detached.

FIG. 7 is a diagram showing an example of two coils having different winding densities.

FIG. 8 is a diagram showing an example of three coils having different lengths.

FIG. 9 shows a fixing roller Z5 according to a seventh embodiment of the present invention.
FIG.

FIG. 10 is a schematic configuration diagram of a conventional IH type fixing roller.

[Explanation of symbols]

 1. Heat roller 11 to 16 Coil. 21 ... Cap (an example of a ring-shaped magnetic material)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kuniaki Nakano, 1-2-28 Tamazo, Chuo-ku, Osaka City Inside Kyocera Mita Corporation (72) Inventor Takayuki Taira 1-2-28, Tamazo, Chuo-ku, Osaka Kyocera Inside Mita Corporation (72) Inventor Toshiyuki Hamada 1-2-28 Tamazo, Chuo-ku, Osaka-shi Kyocera Mita Corporation (72) Inventor Yasuhiro Michishita 1-2-28 Tamazo, Chuo-ku, Osaka-shi Kyocera Mita Corporation F term (reference) 2H033 AA03 BA27 BB18 BE06 3K059 AA08 AB04 AB28 AD03 AD05 AD13

Claims (11)

[Claims] 1. An induction heating type fixing device in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. A fixing device, wherein the fixing roller is formed to have a length protruding outward from both ends of an image area of the heat roller. 2. An induction heating type fixing device in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. Is configured to be close to the inner peripheral surface of the heat roller. 3. The heat roller inner diameter d1, the coil outer diameter d2, and the protrusion amount a of the coil end from the image area are set so as to satisfy d1−d2 ≦ a. Fixing device. 4. The fixing device according to claim 1, wherein a ring-shaped magnetic material is attached to both ends of the coil. 5. An induction heating type fixing device in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material, wherein both ends of the coil are provided. A fixing device characterized in that a ring-shaped magnetic body is attached to the portion. 6. The coil according to claim 1, wherein the coil is divided into a plurality of parts in the axial direction of the heat roller, and the coils are arranged so that the magnetic directions of adjacent coils are opposite to each other.
5. The fixing device according to any one of items 5. 7. An induction heating type fixing device in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material, wherein the coil is A fixing device, which is divided into a plurality of parts in the axial direction of a heat roller, and is arranged so that magnetic directions of adjacent coils are opposite to each other. 8. The fixing device according to claim 1, wherein said coil is detachable by being divided in an axial direction. 9. The fixing device according to claim 8, wherein said splittable coil is formed by combining coils having different lengths and / or winding densities. 10. An induction heating type fixing device in which a coil wound around an axis of the heat roller is disposed inside a cylindrical heat roller formed of a conductive material. The fixing device is characterized in that it is not uniform in the axial direction. 11. An image forming apparatus equipped with the fixing device according to claim 1.