JP2001312165A - Induction coil, its manufacturing method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction coil which is easily manufactured and easily repaired, and to provide its manufacturing method and an image forming device. SOLUTION: Bobbins 6 supporting conductors 14, 15 and 16 are formed by coupling plural bobbin members 11, 12 and 13 which can be attached to/detached from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction coil used in an induction heating type fixing device, a method of manufacturing the same, and an image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus using toner for forming a visible image is provided with a fixing device for fixing a toner image to a recording material such as transfer paper. Such a fixing device has a fixing roller to be heated and a pressure roller pressed against the fixing roller, and when the recording material is nipped and conveyed by these rollers, an unfixed toner image is heated and welded to the recording material. The device is well known. Conventionally, such a fixing device is provided with a halogen lamp, a halogen heater, etc. inside the roller as means for heating the fixing roller, and the fixing roller is heated by the lamp or the like to reach a temperature required for fixing. Was to raise.

Incidentally, image forming apparatuses such as copiers, printers, and facsimile machines heat the surface temperature of a fixing roller once to a predetermined temperature and then adjust the fixing temperature so that the roller can be used without waiting as long as possible. A temperature of about 50 to 90% (for example, 120 ° C. for a fixing temperature of 180 ° C.)
It is configured to be kept on standby. The image forming apparatus naturally consumes a large amount of power even in such a standby state. From the viewpoint of energy saving, it is desirable to reduce the energy consumed in the standby state as much as possible.

In view of the above, various types of fixing systems have been developed which can turn off the power supply during standby because the rise time until the temperature reaches a predetermined temperature is short. One of them is a fixing roller made of a metal conductor. Attention has been focused on an induction heating fixing method for heating the image by an eddy current caused by an electromagnetic wave. FIG. 7 shows an example of a fixing device employing the induction heating fixing method.

In FIG. 7, a fixing roller 1 made of a hollow metal conductor is rotatably supported by a bracket 7 via a bearing 9, and a rotatable pressure roller 2 is pressed against the fixing roller 1. ing. Although not shown, a gear that meshes with a drive gear (not shown) is fitted to the end of the fixing roller 1, and the fixing roller 1 is rotated via the gear by driving the drive gear. When the fixing roller 1 is rotated, the pressure roller 2 is driven to rotate.

A non-magnetic bobbin 6 is provided in the fixing roller 1.
Is provided with an induction coil 3 wound spirally.
The induction coil 3 has lead wires 10a and 10b at both ends. The induction coil 3 causes a high-frequency current to flow from the lead wires 10a and 10b to generate an induced eddy current in the fixing roller 1 by a high-frequency magnetic field generated by the high-frequency current. To generate heat.

In the induction heating fixing device thus configured, the rise time can be shortened, so that the so-called recovery time from the low power mode to the time when printing can be performed can be shortened. Even when the heating state is maintained, the set temperature can be kept low. The induction coil 3 is shown in FIGS.
As shown in (a) and (b), a cylindrical bobbin 6 which is equal to or slightly longer than the fixing width is wound around the entire length thereof.

[0008]

However, when making an induction heating coil, it is a labor and time consuming operation since one winding wire or a stranded wire is wound over the entire length of the bobbin. When the bobbin is to be reused even if the wire is disconnected for some reason, it is necessary to unwind and rewind all the conductors, which is very troublesome.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide an induction coil which can be easily manufactured and easily repaired, a method of manufacturing the same, and an image forming apparatus.

[0010]

In order to solve the above-mentioned problems, the present invention relates to an induction coil used in an induction heating type fixing device, in which a plurality of bobbin members, each of which supports a bobbin, are detachably connected to each other. It is characterized by being formed.

The present invention is effective when the winding is divided and wound for each of the plurality of bobbin members. Further, the present invention is effective when the bobbin is a hollow cylinder and the winding is wound inside the plurality of bobbin members.

Furthermore, the present invention is effective when the bobbin member has the winding wound inside and the bobbin member has the winding wound outside. Further, in order to solve the above problem, the present invention provides a method for manufacturing an induction coil according to any one of claims 1 to 4, wherein a winding is wound around a plurality of bobbin members, and then the bobbin members are connected. It is characterized by doing.

Further, in order to solve the above-mentioned problem, the present invention provides an unfixed toner image on a recording material by using the induction coil according to any one of claims 1 to 4 in a fixing device having a fixing roller. It is characterized by being established in

According to the present invention, the plurality of divided bobbin members are provided at positions substantially corresponding to a main sheet passing portion of a fixing roller through which a predetermined recording material having a width smaller than the maximum size that can pass is passed. A main bobbin member around which the winding for the main coil is wound, and a sub bobbin member around which the winding for the sub coil provided at a position substantially corresponding to the sub paper portion of the fixing roller other than the main paper passing portion. Is effective.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 (a), (b), (c)
It is explanatory drawing explaining the manufacturing procedure of the induction coil which concerns on this invention.

In FIG. 1A, the bobbin 6 is divided into a plurality of, in this example, a central main bobbin member 11 and slave bobbin members 12 and 13 connected to both sides thereof. The central bobbin member 11 has engagement recesses 11a formed at both ends thereof, and the secondary bobbin members 12, 13 have engagement protrusions 1 fitted at one ends thereof into the engagement recesses 11a.
2a and 13a are provided.

The bobbin 6 divided in this way is shown in FIG.
As shown in (b), each bobbin member 11, 1
Conductors 14, 15, 16 as windings are wound around 2, 13, respectively. The winding may be a stranded wire. And
Bobbin members 11, 12, around which conductive wires 14, 15, 16 are wound
As shown in FIG. 1C, the induction coil 3 is completed by fitting the engagement protrusions 12a, 13a of the slave bobbin members 12, 13 into the engagement recess 11a of the center bobbin member 11, as shown in FIG. .

The induction coil 3 manufactured as described above
Is divided and the conductors 14, 15, 16 are wound around the bobbin members 11, 12, 13 in advance, and then the bobbin members 1
1, 12, 13 are connected, so that each of the conductors 14, 15, 1
It becomes easier to wind as much as 6 becomes shorter. Furthermore, even in the case of disconnection, only the bobbin members 11, 12, 13 around which the disconnected conductors 14, 15, 16 have been wound need be replaced, so that
It is easier to handle and less waste than before.

By the way, as shown in FIG. 9, an induction coil 3 in which conductors 14 and 15 are wound around a bobbin 6 is known, and a manufacturing method in the case where the induction coil 3 has one conductor has already been proposed. Have been. According to such a manufacturing method, FIG.
When an induction coil composed of a plurality of conducting wires 14 and 15 as shown in FIG. That is, as shown in FIG.
4 and 15 are inserted into the bobbin 6 shown in FIG.
Adhere to the bobbin 6. After that, when the winding core 17 is removed, the processing of the wire ends 14a and 15a near X becomes a problem. The wire ends 14a, 15a are
(A) As shown in FIG.
, It becomes difficult to remove the core 17. With a single induction coil, there is no problem since the end of the coil becomes the end of the winding core. Some ingenuity is required for the processing of the section.

Therefore, according to the present invention, when the induction coil 3 in which the conductor is wound around the inside of the bobbin member 12 is made,
As shown in FIG. 2A, the conductor 15 is wound around the winding core 17, and the end 15a is inserted into the bobbin member 12 while being extended to form a coil (FIG. 2B). Then, the conductor end 15a
Is bent inward to complete the coil of one bobbin member 12 (FIG. 2C). And the bobbin member 1
In the same manner, coils are completed for each of the bobbin members 11, 12, and 13. If the coils for each of the bobbin members 11, 12, and 13 made in this way are combined and connected as shown in FIG. Induction coil 3 wound inside
Can be easily obtained.

Further, using such a manufacturing method, as shown in FIG. 4, the conducting wire 14 is wound inside the bobbin member 11,
The induction wires 3 wound around the bobbin members 12 and 13 for the conductors 15 and 16 can be easily formed. As shown in FIG. 1, the induction coil 3 in which the coil in which the conducting wire 14 is wound inside the bobbin member 11 is provided in the center of the bobbin as compared with the coil all wound outside as shown in FIG. When the cooling is performed, the central coil that is difficult to cool can be efficiently cooled. Therefore, there is an advantage that a copper wire having relatively low heat resistance can be used for the conductive wire 11.

If the coil is entirely wound inside the bobbin member as in the induction coil of FIG. 3, cooling can be performed easily and efficiently, but the coil wound inside the bobbin member is a coil wound outside. It takes more time to make than. Therefore, as shown in FIG. 4, a coil in the central part where the temperature is likely to rise most is provided inside the bobbin to make it easier to cool. With a wound coil, a coil that is easy to make and has a high cooling effect can be obtained.

As a specific example, as shown in FIG.
In an image forming apparatus in which the maximum sheet passing width is passed on the basis of the center of A3 size length, it is effective that the coil of the conductive wire 11 wound around the bobbin member 11 has the A4 size length width and the entire coil has the A4 width width. Because the center coil is
An inner coil having a high cooling effect is desirable because current flows almost at the time of paper passing, and an outer coil having a relatively low cooling effect is desirable because the end coil does not flow current at the time of paper passing at A4 size vertical width or a smaller size. This is because coils may be used.

Further, in the image forming apparatus having such a configuration, the coil of the bobbin member 11 is used as the main coil, and the bobbin members 12, 1 are used.
The three coils are three slave coils, the length of all the coils is equal to or slightly longer than the width of the A4 size, and the width of the main coil is set to be equal to or slightly longer than the vertical width of the A4 size. An area through which the recording material in the A4 size longitudinal direction of the fixing roller is passed is defined as a main paper-passing area, and the other area is defined as a sub-paper passing area. When a recording material having an A4 size and a vertical width is passed, a current is controlled to flow only through the main coil 11 in the central portion, and a recording material having an A4 size and a horizontal width is passed. In the case, the main coil 11 at the center and the slave coil 12 at the end,
13 can be controlled so that a current flows.

FIG. 6 shows a modification of the bobbin member 21.
The bobbin member 21 of this example is provided with an engagement projection 21a at one end and an engagement recess 21b at the other end. The bobbin member configured as described above can produce an induction coil of any length depending on the number of the bobbin members to be connected only by making only one type. In this case, if the length L of the bobbin member 21 is set to slightly more than 5 cm, 1
These are the bobbin members of the slave coil in FIG. 5, and four can be connected to be used as the bobbin member of the main coil.

[0026]

According to the first aspect of the present invention, since the bobbin supporting the winding is formed by connecting a plurality of detachable bobbin members to each other, the bobbins can be connected in an assembled manner. It is easier to make a coil than when there is no coil, and it is easier to replace some coils.

According to the second aspect of the present invention, since the winding is divided and wound for each of the plurality of bobbin members, the length of the winding is short and the winding is easy. According to the configuration of claim 3, since the bobbin is a hollow cylindrical body and the winding is wound inside the plurality of bobbin members, it is possible to use a conductor that is easily cooled and has relatively low heat resistance. Therefore, costs can be reduced.

According to the fourth aspect of the present invention, since the bobbin member having the winding wound inside and the bobbin member having the winding wound outside, the temperature of the center portion where the temperature tends to rise more than the end portion is increased. An induction coil having a high cooling effect can be easily made.

According to the fifth aspect of the present invention, after winding the plurality of bobbin members, the bobbin members are connected to each other, so that the operation of manufacturing the induction coil is facilitated. According to the configuration of the sixth aspect, the unfixed toner image is fixed on the recording material by the fixing device using the induction coil according to any one of the first to fourth aspects, so that the temperature unevenness of the fixing roller is reduced. And good images can be obtained. Further, since the cooling is possible, the induction coil is also easy to manufacture and inexpensive.

According to the seventh aspect of the present invention, the divided bobbin member is located at a position substantially corresponding to the main sheet passing portion of the fixing roller through which a predetermined recording material having a width smaller than the maximum size that can pass is passed. A main bobbin member around which the provided winding for the main coil is wound, and a sub bobbin member around which the winding for the sub coil provided at a position substantially corresponding to the sub paper portion of the fixing roller other than the main paper passing portion. Has a plurality of coils wound in the circumferential direction of the fixing roller, so that a device having high thermal efficiency can be easily provided.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b) and 1 (c) are explanatory views illustrating a procedure for manufacturing an induction coil according to the present invention.

FIGS. 2 (a) and 2 (b) are explanatory views illustrating the production of an induction coil wound inside a bobbin.

FIG. 3 is an explanatory view showing a completed state of the induction coil of FIG. 2;

FIG. 4 is an explanatory diagram of an induction coil showing another embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a specific example of the induction coil shown in FIG. 4;

FIG. 6 is an explanatory view showing a modification of the bobbin member.

FIG. 7 is a schematic configuration diagram of a conventional induction heating type fixing device.

FIGS. 8A and 8B are explanatory diagrams showing an example of a conventional induction coil.

FIG. 9 is an explanatory diagram showing another example of a conventional induction coil.

FIG. 10 is an explanatory diagram for explaining a problem at the time of manufacturing the induction coil shown in FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 fixing roller 3 induction coil 6 bobbin 11, 12, 13 bobbin member 14, 15, 16 winding 17 winding core

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiaki Higaya 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Masaei Sugawara Shimada, Shibata-cho, Shibata-gun, Miyagi Prefecture 3-1 Tohoku Ricoh Co., Ltd. (72) Inventor Tomotaka Takamura Nakamiku Ichimoji, Shimada-cho, Shibata-cho, Miyagi Prefecture 3-1 F-term in Tohoku Ricoh Co., Ltd. (reference) 2H033 AA31 AA36 BA26 BB12 BB17 BE06 3K059 AA08 AD03 AD35 AD40 CD77

Claims (7)

[Claims] 1. An induction coil used in an induction heating type fixing device, wherein a bobbin supporting a winding is formed by connecting a plurality of detachable bobbin members to each other. 2. The induction coil according to claim 1, wherein
An induction coil, wherein the winding is divided and wound for each of the plurality of bobbin members. 3. The induction coil according to claim 1, wherein the bobbin is a hollow cylinder, and the winding is wound inside the plurality of bobbin members. . 4. The induction coil according to claim 3, wherein
An induction coil comprising: the bobbin member having the winding wound inside; and the bobbin member having the winding wound outside. 5. The method of manufacturing an induction coil according to claim 1, wherein a winding is wound around a plurality of bobbin members, and then the bobbin members are connected. Manufacturing method. 6. An image forming apparatus for fixing an unfixed toner image to a recording material by using the induction coil according to claim 1 in a fixing device mounted on a fixing roller. 7. The image forming apparatus according to claim 6, wherein the plurality of divided bobbin members are provided on a main sheet passing portion of a fixing roller through which a predetermined recording material having a width smaller than a maximum size that can pass is passed. A main bobbin member on which a main coil winding is wound substantially at a position corresponding to the main coil winding, and a slave coil winding provided at a position substantially corresponding to a sub-sheet portion of the fixing roller other than the main sheet passing portion And a slave bobbin member on which the sheet is wound.