JP2005164691A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the warm-up time of a fixing device by shortening the temperature rise time of a fixing roller 2. <P>SOLUTION: The fixing device is equipped with a fixing roller 2 and a pressure roller 4 pressed against the fixing roller 2. The fixing device has two belt support rollers 6 and 8 and an endless belt 10 stretched between the belt support rollers 6 and 8. A partial area of the outer circumferential surface of the endless belt 10 is pressed to a partial area of the outer circumferential surface of the fixing roller 2. The belt support roller 6 is composed of a heat roller. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a fixing device that is mounted on an image forming apparatus such as an electrostatic copying machine, a printer, or a facsimile machine and melts and fixes unfixed toner on a sheet to the sheet.

A fixing device configured to heat the fixing roller not from the inside but from the outside is already known. One typical example of this type of fixing device includes a fixing roller, a pressure roller that is pressed against the fixing roller, and a plurality of heat rollers that are in pressure contact with the fixing roller and incorporate heating means (Patent Document 1). reference). The fixing roller is composed of a mandrel made of an iron hollow tube and silicon rubber covering the periphery of the mandrel. Each of the heat rollers is constituted by an aluminum hollow tube whose surface is coated with a fluororesin.

Since the fixing device directly heats the surface of the fixing roller, the temperature raising time of the fixing roller can be shortened, and therefore the warm-up time can be shortened. However, since the supply of heat to the fixing roller by the plurality of heat rollers is limited to a slight nip width between each of the heat rollers and the fixing roller, the amount of heat supply is limited. As a result, when it is desired to further shorten the heating time of the fixing roller, it is necessary to widen the nip width. However, when the nip width is widened, a local load on the fixing roller increases, so that fixing is performed. The driving torque of the roller increases, and it becomes necessary to strengthen the driving system. In addition, there is a possibility that the silicon rubber of the fixing roller is damaged early and the durability is impaired.
JP 11-84934 A

The main object of the present invention is to shorten the heating time of the fixing roller and shorten the warm-up time without increasing the local load on the fixing roller and without impairing the durability of the fixing roller. And providing a novel fixing device.

According to one aspect of the present invention, in a fixing device including a fixing roller and a pressure roller pressed against the fixing roller, each of a plurality of belt support rollers disposed at a distance from each other, and each of the belt support rollers An endless belt wound around, a partial region of the outer peripheral surface of the endless belt is in pressure contact with a partial region of the outer peripheral surface of the fixing roller, and at least one belt support roller has a built-in heating means Composed of heat rollers,
A fixing device is provided.
According to another aspect of the present invention, in a fixing device including a fixing roller and a pressure roller pressed against the fixing roller, a plurality of belt support rollers arranged at intervals from each other; An endless belt wound between each of the endless belts, and a partial region of the outer peripheral surface of the endless belt is pressed against a partial region of the outer peripheral surface of the fixing roller, and is an outer peripheral surface of at least one belt support roller. Outside the outer peripheral surface in the circumferential region around which the belt is wound, an exciting coil for electromagnetic induction heating is disposed so as to cover at least a partial region of the outer peripheral surface with a gap from the outside.
A fixing device is provided.
One or both of the one belt support roller and the endless belt are preferably made of metal.
One of the belt support rollers is preferably pressed against the fixing roller via an endless belt.
The one belt support roller is formed by a part of the outer peripheral surface of the endless belt being pressed against a part of the outer peripheral surface of the fixing roller. It is preferable that it is arranged at the most upstream position in the rotation direction.
The one belt support roller is formed by a part of the outer peripheral surface of the endless belt being pressed against a part of the outer peripheral surface of the fixing roller. It is preferable that it is arranged at the most downstream position in the rotation direction.
The one belt support roller is preferably driven and rotated by a fixing roller via an endless belt.
Two of the belt support rollers are preferably pressed against the fixing roller via an endless belt.
The two belt support rollers are preferably driven and rotated by a fixing roller via an endless belt.
Of the belt support rollers, two belt support rollers are arranged on the upstream side and the downstream side in the rotation direction of the fixing roller at intervals outside the outer peripheral surface of the fixing roller, and are part of the outer peripheral surface of the fixing roller. It is preferable that the partial region of the outer peripheral surface of the endless belt pressed against the belt is disposed between the two belt support rollers.
Each of the belt support rollers including the two belt support rollers is preferably driven by a fixing roller via an endless belt.
It is preferable that the fixing roller, or both the fixing roller and the pressure roller, have a built-in heating means.
It is preferable that a plurality of convex portions are formed on the outer peripheral surface of the endless belt.
It is preferable that a control device for controlling the temperature of the heat roller is disposed in a space surrounded by the endless belt and the belt support roller.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of a fixing device configured according to the present invention will be described in detail with reference to the accompanying drawings. 1 to 15, substantially the same parts are denoted by the same reference numerals.

Referring to FIG. 1, one embodiment of a fixing device configured in accordance with the present invention is arranged with a fixing roller 2 and a pressure roller 4 pressed against the fixing roller 2 from below, spaced apart from each other. In the embodiment, a plurality of belt support rollers 6 and 8 and an endless belt 10 wound around each of the belt support rollers 6 and 8 are provided. A part of the outer peripheral surface of the endless belt 10 is in pressure contact with a part of the outer peripheral surface of the fixing roller 2. At least one belt support roller, in the embodiment, one belt support roller 6 is composed of a heat roller in which heating means 6H is incorporated. In the space surrounded by the endless belt 10 and the belt support rollers 6 and 8, a temperature sensor, specifically a thermistor S, is used to control the temperature of the belt support roller 6 that is a heat roller. The roller 6 is disposed so as to contact the outer peripheral surface. As another embodiment of the control device for controlling the temperature of the belt support roller 6 that is a heat roller, a thermostat that constitutes a switch for turning on and off the electric circuit of the heat roller can be mentioned. The configuration in which the control device for controlling the temperature of the belt support roller 6 that is a heat roller is provided in the space surrounded by the endless belt 10 and the belt support rollers 6 and 8 contributes to the compactness of the fixing device. Is. The paper P is conveyed substantially horizontally from right to left in FIG.

The fixing device includes a housing (not shown) including a pair of side walls spaced apart in the front and back direction of the paper surface in FIG. 1. The fixing roller 2, the pressure roller 4, and the belt support rollers 6 and 8 include: Between each of the side walls is supported rotatably and parallel to each other. The thermistor S is attached to a support frame (not shown) arranged so as to extend between the side walls. One of the belt support rollers 6 and 8, in the embodiment, the belt support roller 6, which is a heat roller, is pressed against the fixing roller 2 via the endless belt 10. The belt support roller 6 is formed in a nip region 10N of the endless belt 10 with respect to the fixing roller 2 formed by pressing a partial region of the outer peripheral surface of the endless belt 10 against a partial region of the outer peripheral surface of the fixing roller 2. The fixing roller 2 is disposed at the most upstream position (left end in FIG. 1) in the rotation direction (clockwise in FIG. 1).

When the fixing roller 2 is viewed in the axial direction (in FIG. 1, the paper surface is viewed from the front to the back), the virtual horizontal line passing through the axis of the fixing roller 2 is orthogonal to the x axis through the axis of the fixing roller 2 When the imaginary vertical line is the y-axis, the belt support roller 6 is fixed to the outer peripheral surface of the fixing roller 2 in the circumferential direction in the second quadrant (in the embodiment, more fixed than the center in the circumferential direction). The roller 2 is disposed so as to be in pressure contact at a position relatively close to the top of the outer peripheral surface of the roller 2. On the other hand, the belt support roller 8 is downstream of the belt support roller 6 in the rotation direction of the fixing roller 2 and upstream of the conveyance direction of the paper P (in the first quadrant), outside the outer peripheral surface of the fixing roller 2. Arranged at intervals. The heating means 6H is supported in a stationary state between the side walls in the central region of the belt support roller 6 which is a heat roller.

The fixing roller 2 is drivingly coupled to an electric motor M, which is a driving source, via a power transmission mechanism (not shown) including gears. The belt support roller 6, which is a heat roller, is disposed so as to be driven and rotated by the fixing roller 2 via the endless belt 10.

The fixing roller 2 and the pressure roller 4 are composed of an iron mandrel, a silicon sponge that covers the mandrel, and a PFA tube that covers the silicon sponge. Each of the belt support rollers 6 and 8 is formed of an aluminum hollow tube. The belt support roller 8 has a smaller diameter than the belt support roller 6 that is a heat roller. This is because the heat loss due to the belt support roller 8 is reduced. The fixing belt 10 can be made of polyimide resin, Ni or SUS, but in the embodiment, it is made of polyimide resin. The heating means 6H is constituted by a halogen heater, but may be constituted by other heating means, for example, an exciting coil (IH coil) for electromagnetic induction heating (other examples shown in FIGS. 2 to 5 and FIG. 15). The same applies to the embodiment).

When the fixing roller 2 is driven to rotate clockwise in FIG. 1 by the electric motor M, the pressure roller 4 is driven counterclockwise. At the same time, the belt support roller 6 as a heat roller is driven to rotate counterclockwise in FIG. 1 by the fixing roller 2 via the endless belt 10. As a result, the endless belt 10 is driven and rotated in the same counterclockwise direction, and the belt support roller 8 is also driven and rotated in the same counterclockwise direction via the endless belt 10. When the halogen heater constituting the heating unit 6H is energized and heat generation is started, heat from the heating unit 6H is transmitted from both the belt support roller 6 and the endless belt 10 which are heat rollers to the fixing roller 2, and the fixing roller 2 is started. The heat transmitted to the fixing roller 2 is also transmitted to the pressure roller 4. After the surface temperature of the fixing roller 2 reaches a predetermined temperature from room temperature, the sheet P on which the toner is transferred on one side (upper surface) is conveyed substantially horizontally from right to left in FIG. After passing through the nip portion of the roller 4, the unfixed toner transferred to one side of the paper P is melted and fixed on one side of the paper P by the fixing roller 2.

According to the fixing device according to the present invention, a partial region of the outer peripheral surface of the endless belt 10 is configured to be in pressure contact with a partial region of the outer peripheral surface of the fixing roller 2. That is, the flexible endless belt 10 is pressed and formed along a partial region of the outer peripheral surface of the fixing roller 2 to form the nip region 10N, so that the nip width for heating the fixing roller 2 is significantly larger than the conventional one. Can be increased. As a result, the heating time of the fixing roller 2 can be shortened and the warm-up time of the fixing device can be shortened without increasing the local load on the fixing roller 2 and without impairing the durability of the fixing roller 2. Can do. Such operational effects can be obtained in substantially the same manner in other embodiments described later.

In the fixing device, since the belt support roller 6 as a heat roller is pressed against the fixing roller 2 via the endless belt 10, the heat from the halogen heater constituting the heating means 6H is supported by the belt as the heat roller. Since both the roller 6 and the endless belt 10 are transmitted to the fixing roller 2, the heat transfer efficiency to the fixing roller 2 is improved and the temperature rise time of the fixing roller 2 is shortened, so that the warm-up time of the fixing device is shortened. Is done.

In the fixing device, the belt support roller 6 as a heat roller is formed on the fixing roller 2 formed by pressing a part of the outer peripheral surface of the endless belt 10 against a part of the outer peripheral surface of the fixing roller 2. In the nip region 10N of the endless belt 10, since it is disposed at the most upstream position (left end in FIG. 1) in the rotation direction of the fixing roller 2 (clockwise in FIG. 1), it passes through the belt support roller 6 that is a heat roller. The loss of heat transmitted to the endless belt 10 can be reduced, which contributes to shortening the heating time of the fixing roller 2.

In the fixing device, the belt support roller 6 that is a heat roller is disposed so as to be driven and rotated by the fixing roller 2 via the endless belt 10, so that the belt support rollers 6 and 8 are driven to rotate. Since there is no need to provide any special means, it is possible to reduce the cost, size and weight of the fixing device.

Next, another embodiment of the fixing device according to the present invention will be described with reference to FIG. The fixing device shown in FIG. 2 differs from the fixing device shown in FIG. 1 in that a belt support disposed on the downstream side of the fixing roller 2 in the rotational direction of the fixing roller 2 with respect to the belt support roller 6 that is a heat roller. The roller 8 is composed of a heat roller with a built-in heating unit 8H, the fixing roller 2 has a built-in heating unit 2H, and the pressure roller 4 has a built-in heating unit 4H. Since the other configuration is substantially the same, duplicate description is omitted. The heating means 8H, 2H and 4H are each composed of a halogen heater or the like, and are stationary between the side walls of the fixing device housing in the central regions of the belt support roller 8, the fixing roller 2 and the pressure roller 4, respectively. Supported by the state. In this embodiment, the fixing roller 2 and the pressure roller 4 include a mandrel made of a metal hollow tube such as aluminum or iron, and an elastic body such as silicon rubber covering the mandrel, and the surface of the elastic body is It is coated from PFA, PTFE or the like, or coated with a PFA tube or the like. According to this fixing device, it is possible to raise the fixing roller 2 from room temperature to a predetermined temperature in a shorter time, and therefore it is possible to warm up the fixing device in a shorter time.

As the material constituting the endless belt 10, heat-resistant Ni, SUS, polyimide resin, and the like can be considered, but after heating during the fixing operation, the rotation of the fixing roller 2 is stopped and the endless belt 10 is fixed. When the cooling is performed at a temperature lower than the temperature, the belt supporting rollers 6 and 8 that are wound may be deformed into an arc shape having a radius (formation may occur). In particular, when deformation occurs in the arc region of the endless belt 10 wound around the belt support roller 8 having a small radius, the endless belt 10 is generated even if the fixing roller 2 is next driven to rotate the endless belt 10. Deformation becomes resistance, and the endless belt 10 may not be able to rotate. In the embodiment shown in FIG. 2, since the belt support roller 8 having a small radius also includes the heating means 8H, the belt support roller 8 is heated to a predetermined temperature in advance before the next fixing operation is performed. Thus, it is possible to prevent a problem that the endless belt 10 cannot be rotated due to molding. In the fixing device shown in FIG. 2, there are other embodiments in which the heating means 2H and 4H in the fixing roller 2 and the pressure roller 4 are omitted.

FIG. 3 shows still another embodiment of the fixing device according to the present invention. In the fixing device shown in FIG. 3, the belt support roller 8 disposed on the downstream side in the rotation direction of the fixing roller 2 with respect to the belt support roller 6 is composed of a heat roller having a built-in heating means 8H, and the fixing roller. 2 is in pressure contact with the endless belt 10 in the first quadrant. The belt support roller 8 is formed in a nip region 10N of the endless belt 10 with respect to the fixing roller 2 formed by pressing a partial region of the outer peripheral surface of the endless belt 10 against a partial region of the outer peripheral surface of the fixing roller 2. The fixing roller 2 is disposed at the most downstream position in the rotation direction, and is driven to rotate by the fixing roller 2 via the endless belt 10. On the other hand, the belt support roller 6 is composed of a heat roller with a built-in heating means 6H, and is upstream of the belt support roller 8 in the rotation direction of the fixing roller 2 and downstream of the conveyance direction of the paper P. The fixing roller 2 is disposed outside the outer peripheral surface with an interval (disposed in the second quadrant). Other configurations are substantially the same as those of the fixing device shown in FIG.

In the fixing device shown in FIG. 3, when the fixing roller 2 is rotationally driven by the electric motor M, the belt support roller 8 pressed against the fixing roller 2 via the endless belt 10 is driven to rotate. The endless belt 10 is pulled with respect to the belt support roller 8 on the downstream side in the rotation direction of the fixing roller 2 and downward, so that the endless belt 10 is placed on the outer peripheral surface of the fixing roller 2 in the nip region 10N of the endless belt 10 with respect to the fixing roller 2 Since the pressing force is applied to the endless belt 10, the endless belt 10 is sufficiently adhered to the fixing roller 2, heat is effectively transmitted, and the fixing roller 2 is heated for a shorter time.

FIG. 4 shows still another embodiment of the fixing device according to the present invention. In the fixing device shown in FIG. 4, the two belt support rollers 6 and 8 are pressed against the outer peripheral surface of the fixing roller 2 via the endless belt 10 and are driven to rotate by the fixing roller 2 via the endless belt 10. It is configured as follows. The belt support roller 6 is disposed in the second quadrant, and the belt support roller 8 is disposed in the first quadrant. The belt support rollers 6 and 8 are each composed of a heat roller in which heating means 6H and 8H composed of a halogen heater or the like are incorporated. Other configurations are substantially the same as those of the fixing device shown in FIG. According to this fixing device, heat transfer to the fixing roller 2 is effectively performed by both the belt support rollers 6 and 8 and the endless belt 10, which greatly contributes to shortening of the temperature raising time of the fixing roller 2.

FIG. 5 shows still another embodiment of the fixing device according to the present invention. The fixing device shown in FIG. 5 includes three belt support rollers 6, 8, and 12 that are spaced apart from each other. Of the belt support rollers 6, 8 and 12, two belt support rollers 6 and 8 are arranged at intervals outside the outer peripheral surface of the fixing roller 2 on the upstream side and the downstream side in the rotation direction of the fixing roller 2, respectively. ing. The belt support roller 12 is disposed above the fixing roller 2 at an interval between the belt support rollers 6 and 8. The belt support roller 6 is disposed in the second quadrant, and the belt support roller 8 is disposed in the first quadrant. The belt support roller 8 is substantially disposed in the boundary region between the first quadrant and the second quadrant. A partial region (nip region 10N) of the outer peripheral surface of the endless belt 10 pressed against a partial region of the outer peripheral surface of the fixing roller 2 is disposed between the two belt support rollers 6 and 8. The belt support rollers 6, 8 and 12 are each composed of a heat roller in which heating means 6H, 8H and 12H composed of a halogen heater or the like are incorporated. The belt support rollers 6, 8 and 12 are driven by the fixing roller 2 through the endless belt 10. Other configurations are substantially the same as those of the fixing device shown in FIG. According to this fixing device, since only the endless belt 10 is pressed against the fixing roller 2, the local load on the fixing roller 2 is most reduced, and the durability of the fixing roller 2 is more sufficiently secured. .

In each of the fixing devices, it is desirable to transmit the heat transmitted from the heat roller to the endless belt 10 to the fixing roller 2 as efficiently as possible. In order to achieve this object, it is preferable to increase the surface area of the outer peripheral surface (surface) of the endless belt 10 that is pressed against the surface of the fixing roller 2. In order to increase the surface area of the outer peripheral surface of the endless belt 10, a plurality of convex portions may be formed on the outer peripheral surface of the substantially flat endless belt 10. 6 to 14 schematically show an embodiment of the endless belt 10 configured as described above.

6 and 7, a plurality of convex portions 10a are formed on the outer peripheral surface of endless belt 10 at intervals. Each of the convex portions 10a has a curved outer surface. In the embodiment, the outer surface of each of the convex portions 10a is substantially hemispherical. In the embodiment shown in FIG. 6, the convex portions 10 a are irregularly arranged on the outer peripheral surface of the endless belt 10, but may be regularly arranged in the circumferential direction and / or the width direction of the endless belt 10.

With reference to FIGS. 8, 9 and 10, a plurality of convex portions 10 b are formed on the outer peripheral surface of the endless belt 10 at intervals. Each of the convex portions 10b has a rectangular cross section, and is arranged linearly in the circumferential direction and the width direction of the endless belt 10 with a certain interval. In the embodiment shown in FIGS. 8 to 10, the convex portions 10 b are regularly arranged on the outer peripheral surface of the endless belt 10, but are irregularly arranged in the circumferential direction and / or the width direction of the endless belt 10. Also good.

In the embodiment shown in FIG. 8 to FIG. 10, the convex portion 10 b is configured to have a rectangular cross section, but as shown in FIG. 11, each top peripheral edge of the convex portion 10 b is chamfered to It is good also as the convex part 10c which removed the sharp edge. The chamfered shape of the convex portion 10c may be a flat surface as shown or a curved surface (not shown).

In the embodiment shown in FIG. 12, each of the convex portions 10 b is viewed from the virtual line inclined in the width direction with respect to the circumferential direction of the endless belt 10 and the width direction of the endless belt 10 when the endless belt 10 is viewed from the plane. The virtual lines that are inclined in the circumferential direction and arranged along the virtual lines that intersect with each other are spaced apart from each other. Each of the convex portions 10 b is arranged in a mesh shape that is obliquely crossed with respect to the circumferential direction of the endless belt 10 on a plane where the endless belt 10 is developed.

In the embodiment shown in FIG. 13, each of the convex portions 10 b is formed to be zigzag continuous in the circumferential direction with an interval in the width direction of the endless belt 10.

In the embodiment shown in FIG. 14, each of the convex portions 10 b is formed to be zigzag continuous in the width direction with an interval in the circumferential direction of the endless belt 10.

As described above, by forming the plurality of convex portions 10a, 10b, 10c, etc. on the outer peripheral surface of the endless belt 10, the outer peripheral surface of the endless belt 10 having an increased surface area is pressed against the surface of the fixing roller 2 having elasticity. By doing so, the contact area of the endless belt 10 with the fixing roller 2, and thus the nip width of the endless belt 10 with respect to the fixing roller 2 is increased, and the heat stored in the endless belt 10 is efficiently transferred to the fixing roller 2. It becomes possible. As a result, it is possible to further shorten the heating time of the fixing roller 2 and further shorten the fixing device warm-up time. In addition, it goes without saying that the cross-sectional shape and arrangement of the plurality of convex portions formed on the outer peripheral surface of the endless belt 10 are not limited to the above embodiment, and various other combinations are conceivable.

In the above-described embodiment shown in FIGS. 1 and 2, the belt support roller 6 is configured to be driven and rotated by the fixing roller 2 via the endless belt 10, but instead, the belt support roller 6 is It is also possible to interlock with the fixing roller 2 by drivingly connecting to a power transmission mechanism such as a gear for driving the fixing roller 2. Further, the belt support roller 6 can be driven to rotate independently of the fixing roller 2. The same can be said for the above-described embodiments shown in FIGS.

FIG. 15 shows still another embodiment of a fixing device constructed according to the present invention. The fixing device shown in FIG. 15 includes two belt support rollers 6 and 8 that are spaced apart from each other. The belt support rollers 6 and 8 are arranged at intervals on the outer side of the outer peripheral surface of the fixing roller 2 on the upstream side and the downstream side in the rotation direction of the fixing roller 2, respectively. The belt support roller 6 is disposed in the second quadrant, and the belt support roller 8 is disposed in the first quadrant. A partial region (nip region 10N) of the outer peripheral surface of the endless belt 10 pressed against a partial region of the outer peripheral surface of the fixing roller 2 is disposed between the two belt support rollers 6 and 8. In the embodiment, the belt supporting rollers 6 and 8 do not have a heating means. The belt support rollers 6 and 8 are driven by the fixing roller 2 via the endless belt 10.

At least one of the two belt support rollers 6 and 8, in the embodiment, the endless belt 10 is wound around the outer peripheral surface of the belt support roller 6 disposed on the upstream side. An excitation coil 20 for electromagnetic induction heating, that is, an IH coil 20 is disposed outside the outer peripheral surface in the circumferential region so as to cover at least a partial region of the outer peripheral surface with a gap from the outside. In the embodiment, the belt support roller 6 is formed of a hollow tube made of metal such as aluminum, and the endless belt 10 is formed of metal such as Ni or SUS. The IH coil 20 is a coil that is spirally wound in the axial direction of the belt support roller 6. When a high frequency current flows through the IH coil 20 from a high frequency power source (not shown), an induced eddy current is generated in the belt support roller 6 by the generated high frequency magnetic field, and the belt support roller 6 and the endless belt 10 are heated by Joule heat. . The heat of the belt support roller 6 and the endless belt 10 heated by the IH coil 20 is transmitted to the fixing roller 2 through the endless belt 10. Other configurations are substantially the same as those of the fixing device shown in FIG.

According to this fixing device, the local load on the fixing roller 2 is not increased, and the durability of the fixing roller 2 is not impaired, and the electromagnetic induction heating method is used to pass the belt support roller 6 and the endless belt 10. Since the fixing roller 2 can be efficiently heated, it is possible to shorten the heating time of the fixing roller 2 and shorten the warm-up time of the fixing device. In this embodiment, an embodiment in which the IH coil 20 is also provided on the belt support roller 8 side and the belt support roller 8 together with the belt support roller 6 is electromagnetically heated is also possible.

It is of course possible to apply such an electromagnetic induction heating method to the embodiment of the fixing device shown in FIGS. In that case, the heating means 2H and 4H are incorporated in the fixing roller 2 and the pressure roller 4, respectively, in other embodiments in which the heating means 6H, 8H and 12H are not incorporated in the belt support rollers 6, 8 and 12, respectively. Various embodiments, in which the heating means 2H, 4H, 6H, 8H and 12H are not used at all, other embodiments in which the heating means are incorporated in any of the belt support rollers 6, 8, 12 and the like. Application examples are possible. In any case, the heating time of the fixing roller 2 can be further shortened by effectively combining the IH coil 20, other heating means such as a halogen heater, and the belt support rollers 6, 8 and 12. The warm-up time of the fixing device can be further shortened.

In the above embodiment shown in FIG. 15, the belt support roller 6 is formed from a metal hollow tube, and the endless belt 10 is formed from metal. In other embodiments in which the belt support roller 6 is made of metal and the endless belt 10 is made of synthetic resin such as polyamide resin, the belt support roller 6 is made of synthetic resin. Furthermore, still another embodiment in which the endless belt 10 is made of metal is possible. Further, when the endless belt 10 or the belt support roller 6 is made of synthetic resin, there is still another embodiment in which a conductive metal layer is disposed on the outer peripheral surface facing the IH coil 20.

1 is a schematic configuration diagram illustrating an embodiment of a fixing device configured according to the present invention. FIG. 3 is a schematic configuration diagram illustrating another embodiment of a fixing device configured according to the present invention. FIG. 9 is a schematic configuration diagram illustrating still another embodiment of a fixing device configured according to the present invention. FIG. 9 is a schematic configuration diagram illustrating still another embodiment of a fixing device configured according to the present invention. FIG. 9 is a schematic configuration diagram illustrating still another embodiment of a fixing device configured according to the present invention. 1 is a perspective view schematically showing a configuration of an embodiment of an endless belt provided in a fixing device configured according to the present invention. FIG. AA arrow sectional drawing of FIG. FIG. 6 is a perspective view schematically showing a configuration of another embodiment of an endless belt provided in a fixing device configured according to the present invention. BB arrow sectional drawing of FIG. FIG. 9 is a developed sectional view taken along the line CC in FIG. 8. Sectional drawing which shows other embodiment of the convex part formed in the endless belt shown in FIG. FIG. 9 is a perspective view schematically showing a configuration of still another embodiment of an endless belt provided in a fixing device configured according to the present invention. FIG. 9 is a perspective view schematically showing a configuration of still another embodiment of an endless belt provided in a fixing device configured according to the present invention. FIG. 9 is a perspective view schematically showing a configuration of still another embodiment of an endless belt provided in a fixing device configured according to the present invention. FIG. 9 is a schematic configuration diagram illustrating still another embodiment of a fixing device configured according to the invention.

Explanation of symbols

2: fixing roller 4: pressure rollers 6, 8, 12: belt support roller 10: endless belts 10a, 10b, 10c: convex portion 20: IH coils 2H, 4H, 6H, 8H, 12H: heating means M: electric motor P : Paper

Claims (14)

In a fixing device including a fixing roller and a pressure roller pressed against the fixing roller, a plurality of belt support rollers arranged at a distance from each other, and an endless belt wound around each of the belt support rollers; A partial region of the outer peripheral surface of the endless belt is pressed against a partial region of the outer peripheral surface of the fixing roller, and at least one belt support roller is composed of a heat roller with a built-in heating means.
A fixing device. In a fixing device including a fixing roller and a pressure roller pressed against the fixing roller, a plurality of belt support rollers arranged at a distance from each other, and an endless belt wound around each of the belt support rollers; A partial region of the outer peripheral surface of the endless belt is pressed against a partial region of the outer peripheral surface of the fixing roller, and is an outer peripheral surface of at least one belt support roller in a circumferential region around which the endless belt is wound. On the outer side of the outer peripheral surface, an exciting coil for electromagnetic induction heating is disposed so as to cover at least a part of the outer peripheral surface with a gap from the outer side,
A fixing device. The fixing device according to claim 2, wherein one or both of the one belt support roller and the endless belt is made of metal. The fixing device according to claim 1, wherein one of the belt support rollers is pressed against the fixing roller via an endless belt. The one belt support roller is formed by a part of the outer peripheral surface of the endless belt being pressed against a part of the outer peripheral surface of the fixing roller. The fixing device according to claim 4, wherein the fixing device is disposed at a most upstream position in a rotation direction of the head. The one belt support roller is formed by a part of the outer peripheral surface of the endless belt being pressed against a part of the outer peripheral surface of the fixing roller. The fixing device according to claim 4, wherein the fixing device is disposed at a most downstream position in the rotation direction of the fixing member. The fixing roller according to any one of claims 4 to 6, wherein the one belt support roller is driven and rotated by a fixing roller via an endless belt. The fixing device according to claim 1, wherein two of the belt support rollers are pressed against the fixing roller via an endless belt. The fixing roller according to claim 8, wherein the two belt support rollers are driven to rotate by the fixing roller via an endless belt. Of the belt support rollers, two belt support rollers are arranged on the upstream side and the downstream side in the rotation direction of the fixing roller at intervals outside the outer peripheral surface of the fixing roller, and are part of the outer peripheral surface of the fixing roller. The fixing device according to claim 1, wherein the partial region of the outer peripheral surface of the endless belt pressed against the belt is disposed between the two belt support rollers. The fixing device according to claim 10, wherein each of the belt support rollers including the two belt support rollers is driven by a fixing roller via an endless belt. The fixing roller according to claim 1, wherein the fixing roller or both the fixing roller and the pressure roller includes a heating unit. The fixing roller according to claim 1, wherein a plurality of convex portions are formed on an outer peripheral surface of the endless belt. The fixing roller according to claim 1, wherein a control device for controlling the temperature of the heat roller is disposed in a space surrounded by the endless belt and the belt support roller.

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