JP2008096738A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the load of the leading edge of a recording medium on the surface of a fixing roll when the recording medium rushes in a press-contact part between the fixing roll and an endless belt, and to suppress the damage on the surface of the fixing roll, regarding a fixing device configured to fix a toner image on a recording paper by heating and pressurizing. <P>SOLUTION: A pressure pad 3 for bringing the fixing roll 1 in press contact with the endless belt 2 includes: a first pad 3a disposed on the upstream side in the moving direction of the recording paper P; and a second pad 3b disposed on the downstream side. The first pad is formed of materials more deformable than that of the second pad, and also, the first pad is supported by an internal spring 7b, and the first pad is easily deformable in a retract direction with the rush-in of the recording paper. On the other hand, regarding a pressure lever 10 for pressurizing the pressure pad against the fixing roll 1, the end part on the downstream side in the rotational moving direction of the endless belt is rotatably supported by a stud 10a, and the end part on the upstream side is supported through a pressure spring 9. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a fixing device that is used in an image forming apparatus such as a printer, a copying machine, or a facsimile machine, and heats and presses an unfixed toner image held on a recording medium to fix it on the recording medium.

  As a fixing device of an image forming apparatus that forms a visible image using toner, a heated endless circumferential surface moves around, and a pressure member supported while being in pressure contact with the fixing member Are often used. Then, the recording medium holding the toner is sent between the fixing member and the pressure member, the recording medium is sandwiched between them, and the recording medium is conveyed by the circular movement of the endless peripheral surface of the fixing member. Pass between. As a result, the recording medium is pressed against the fixing member, and the unfixed toner image is heated and pressed to be fixed to the recording medium.

As a fixing member used in such a fixing device, for example, a fixing roll in which an elastic body layer and a surface release layer are formed on the outer periphery of a hollow cylindrical core metal such as aluminum is used. When the fixing roll having the elastic layer receives a pressing force from the pressure member, the fixing roll allows a predetermined deformation in a contact area (nip portion).
On the other hand, as described in Patent Document 1, as the pressure member, a pressure pad is disposed inside the endless belt, and the pressure pad attaches the endless belt from the inside of the endless belt to the fixing member. There is a thing which presses to the outer peripheral surface. The pressure pad presses the endless belt against the fixing member and supports the endless belt in a state in which the endless belt is not stretched in the circumferential direction, whereby the endless belt is supported by the endless peripheral surface of the fixing member. It moves around in conjunction with.

In such a belt nip type fixing device, the width of the belt nip can be increased, and since the recording medium is heated while passing through the belt nip, it is sufficient even if the conveyance speed of the recording medium is increased. Fixing time can be secured. Further, since a larger amount of heat can be given to the toner, it is suitable for a color copying machine for fixing a multilayer toner.
Japanese Patent Laid-Open No. 2005-4126

In the fixing device as described above, there is a problem that a solution described below is desired.
In the state where the leading end of the thick recording medium P has entered the area where the pressing member 23 is pressed against the fixing roll 21 via the endless belt 22, and the leading end has not reached the downstream portion of the pressing area, FIG. As shown, the elastic layer 21 a of the fixing roll 21 is deformed depending on the thickness of the recording medium P. In particular, when the pressurizing member 23 is pressed through an elastic member (not shown) such as a spring, the pressurizing member 23 retreats due to the entry of the leading end of the recording medium P, and the pressing force by the elastic member causes the recording medium to press. It acts on the tip edge Pa of P in a concentrated manner. For this reason, the elastic layer 21a of the fixing roll 21 undergoes intensive deformation along the leading edge Pa of the recording medium P, and a large load is generated on the elastic layer 21a. In addition, when the surface release layer 21b is coated on the outermost layer, a large load is generated on the surface release layer 21b or the boundary portion between the surface coating layer 21b and the elastic layer 21a. Thereby, in a usage pattern in which a recording medium having a large thickness is repeatedly used, damage to the surface release layer 21b or peeling of the surface release layer 21b from the elastic layer 21a is likely to occur. If the elastic layer 21a or the surface release layer 21b is damaged or peeled off, it will cause problems such as poor fixing and image quality deterioration, and the fixing roll 21 needs to be replaced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a belt nip when the leading end of a recording medium is fed into a belt nip that is a pressure contact portion between a fixing roll and an endless belt. It is an object of the present invention to provide a fixing device that prevents the load from concentrating on the fixing roll at the entrance of the fixing roller and suppresses damage to the surface of the fixing roll.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that an outer peripheral surface has an elastic layer and is driven to rotate in a heated state, and a part is in contact with the peripheral surface of the fixing roll. And an endless belt supported so as to be capable of circular movement, and a pressure pad that is disposed along the axial direction of the fixing roll and presses the endless belt against the fixing roll from the inside of the endless belt; A support member that supports the pressure pad; and supports the support member in the vicinity of both ends of the pressure pad in the axial direction of the fixing roll, and supports one end of the endless belt in a circumferential movement direction that can rotate. A pressure lever that applies a pressing force of the pressure pad to the fixing roll via an elastic member, and a toner image is formed at a contact portion between the fixing roll and the endless belt. Attached Recording medium, to provide a fixing device, characterized in that the pressure lever is fed from the supported end portion side via the elastic member.

  The invention according to claim 2 has an elastic layer on the outer peripheral surface, and a fixing roll that is rotationally driven in a heated state, and a part of the fixing roll is in contact with the peripheral surface of the fixing roll and is supported so as to be able to move around. An endless belt that is arranged along the axial direction of the fixing roll, a pressure pad that presses the endless belt against the fixing roll from the inside of the endless belt, and the axial direction of the fixing roll. The pressure pad is supported at both ends of the pressure pad, one end of the endless belt in the circumferential movement direction is rotatably supported, and the other end is connected to the fixing roll of the pressure pad via an elastic member. A pressure lever for applying a pressing force of the pressure sensor, wherein the pressure pad is in contact with the endless belt in the vicinity of the edge on the inlet side of the recording medium in the circumferential movement direction of the endless belt. Pressure welding Displacement due provides a fixing device, characterized in that it is likely to occur than the outlet side.

  According to a third aspect of the present invention, in the fixing device according to the first or second aspect, the pressure pad is divided into a plurality of portions arranged in a circumferential movement direction of the endless belt, It is assumed that these portions can be displaced independently.

  According to a fourth aspect of the present invention, there is provided the fixing device according to the third aspect, wherein the recording medium is fed between the fixing roll and the endless belt at a portion provided on the most entrance side of the pressure pad. It is assumed that the pressure lever is supported by an elastic member that is deformed when deformed.

  According to the configuration of the first aspect of the present invention, the direction in which the recording medium is fed to the pressure contact portion between the fixing roll and the endless belt is the end portion side that is supported so that the pressure lever can be rotated, that is, the lever. In principle, the pressure pad is fed not from the fulcrum side when pressing the pressure pad, but from the action point side. Thus, the elastic member is elastically deformed by the recording medium entering the pressure contact portion, and the pressure pad moves backward with respect to the fixing roll, but the displacement amount is large on the inlet side of the pressure contact portion and small on the outlet side. . For this reason, on the outlet side, the amount of decrease in the pressure contact force of the pressure pad is small and the pressure contact force remains. Accordingly, the pressure contact force of the pressure pad by the pressure lever acts on the outlet side in a distributed manner, and the concentration of the pressure contact force on the leading edge of the recording medium on the inlet side can be reduced. Therefore, the load acting on the elastic layer of the fixing roll is reduced, and the durability of the fixing roll is improved.

  According to the configuration of the second aspect of the invention, the pressure pad is formed near the edge of the pressure pad on the inlet side of the pressure contact portion between the fixing roll and the endless belt, and is easily displaced by the pressure force. Yes. In other words, the pressure pad is likely to be displaced by the pressure contact force at the upstream portion in the circumferential movement direction of the fixing roll, so that the deformation easily occurs when the leading edge of the recording medium is fed and is urged by the pressure lever. The retraction amount of the entire pressure pad becomes smaller. For this reason, the decrease amount of the pressure contact force of the pressure pad is small on the outlet side, that is, the downstream side of the pressure contact portion, and the pressure contact force remains and acts. As a result, the pressure contact force of the pressure pad by the pressure lever acts in a distributed manner on the outlet side, and the concentration of the pressure contact force on the leading edge of the recording medium on the inlet side is reduced.

  According to the configuration of the invention relating to claim 3, the pressure distribution of the pressure pad pressing the fixing roll via the endless belt can be easily controlled in the circumferential movement direction of the fixing roll. Then, when the recording medium enters the press contact portion, only the vicinity of the inlet of the pressure pad can be greatly displaced, and the change in the press contact force on the downstream side can be reduced. As a result, the pressure contact force can be easily dispersed without being concentrated on the inlet side. Further, by adjusting the pressure distribution in the circumferential movement direction of the fixing roll, it is possible to secure the press contact force necessary for good fixing and maintain the peelability of the recording medium fed from the press contact portion.

  According to the configuration of the invention of claim 4, since the entrance side of the press contact portion into which the leading end of the recording medium enters is supported via the elastic member, the pressure pad is deformed by the elastic member when the recording medium enters. Is retracted, and the displacement of the pressure lever and the downstream portion of the pressure pad can be reduced. Thereby, the pressure contact force of the pressure pad is dispersed, and the load on the fixing roll is reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing a fixing device according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing a pressure contact mechanism between a fixing roll and a pressure pad in the fixing device.
In this fixing device, an endless belt 2 is disposed in contact with an outer peripheral surface of a fixing roll 1 having a built-in heating source, and includes a first pad 3a and a second pad 3b inside the endless belt 2. A pressure pad 3 is arranged. The pressure pad 3 is brought into contact with the inner peripheral surface of the endless belt 2 to press the outer peripheral surface of the endless belt 2 against the fixing roll 1 to form a press contact portion.

Further, inside the endless belt 2, an oil supply member 4 that supplies lubricating oil to the inner peripheral surface of the endless belt 2, guide members 5 a and 5 b that guide the circumferential movement of the endless belt 2, and the endless belt 2 are added. A sliding sheet 6 that is sandwiched between the pressure pad 3 and smoothes the revolving movement of the endless belt 2, a pad support 7a that supports the first pad 3a, and a pad support 7a that supports the first pad 3a. An internal spring 7b for urging one pad 3a against the fixing roll 1 and a spring receiving member 7c are provided.
Then, these members disposed inside the endless belt 2 are supported by a pressure frame 8 as a support member, and the pressure frame 8 is urged toward the fixing roll 1 by a pressure lever 10. One end of the pressure lever 10 is rotatably supported, and the other end is supported by a pressure spring 9. The pressure frame 8 is urged by an elastic repulsion force of the pressure spring.

  The recording paper P (recording medium) holding the unfixed toner image is fed into the pressure contact portion between the rotation-driven fixing roll 1 and the endless belt 2, and the recording paper P (recording medium) from the fixing roll 1 in the pressure contact portion is sent to the pressure contact portion. The toner image is heated and pressurized by heat transfer, and is pressed onto the recording paper P.

The fixing roll 1 has an elastic body layer 1c made of silicone rubber on the surface of a metal cylindrical core metal 1b having conductivity, and a release layer 1d made of a fluororesin on the outer peripheral surface of the elastic body layer 1c. And is rotatably supported by a main body frame (not shown) of the image forming apparatus.
The cylindrical cored bar 1b of the fixing roll 1 can be made of a metal such as aluminum, iron or stainless steel having excellent thermal conductivity and rigidity. In this embodiment, a cylindrical body made of aluminum having an outer diameter of 33.8 mm and an inner diameter of 27.8 mm is used as a core metal, and an elastic layer 1c is made of 0.6 mm thick HTV (High Temperature Vulcanizing) silicone rubber. A fluororesin tube having a thickness of 30 μm is wound around the surface of the elastic layer 1c as the release layer 1d.

  As shown in FIG. 1, a halogen lamp 1 a having a length substantially the same as the axial length of the fixing roll 1 is disposed inside the fixing roll 1 as a heating source. Heat is supplied over the entire length. In the present embodiment, a halogen lamp is incorporated as a heating source, but a lamp other than the halogen lamp may be used. Further, other elastic materials can be used for the elastic layer 1 c of the fixing roll 1.

  The endless belt 2 has a two-layer structure of a base layer and a surface layer. The base layer has a heat-resistant resin such as polyimide, polyamide, polyamideimide, etc. in consideration of heat resistance, strength, and surface smoothness. Metal such as aluminum and stainless steel is used, and the surface layer is made of silicone rubber, fluorine rubber, fluorine coating or the like that has high heat resistance and high releasability from the toner.

  The pressure pad 3 is disposed on the downstream side of the first pad 3 a that is elastically deformed when pressed against the fixing roll 1 and the first pad 3 a in the circumferential movement direction of the endless belt 2. It is comprised with the 2nd pad 3b whose hardness is higher than 3a. The first pad 3a is pressed against the outer peripheral surface of the fixing roll 1 through the endless belt 2 and the sliding sheet 6 by the pressure spring 9 that urges the internal spring 7b and the pressure lever 10 toward the fixing roll 1 side. ing. The second pad 3 b is pressed against the fixing roll 1 by the pressure frame 8, the pressure lever 10 and the pressure spring 9.

The first pad 3a is made of silicone rubber having a rubber hardness of 18 ° to 24 ° (JIS A), and is fitted to and supported by a synthetic resin pad support member 7a. Although the rubber hardness of the first pad 3a depends on the relationship with the elastic body layer 1c of the fixing roll 1, it is desirable to set it to about 21 ° in the present embodiment.
In addition, the first pad 3a may be changed in hardness in the conveyance direction of the recording paper P, and the upstream portion can be formed of a material that is flexible and easily deformed.

The internal spring 7b has a smaller spring coefficient than the pressure spring 9 that biases the pressure lever 10, and the second pad 3b is biased by biasing the pad support member 7a via the internal spring 7b. Independently, the pressing force of the first pad 3a against the fixing roll 1 is set.
In the present embodiment, the pressure of the internal spring 7 b is about 60% of the pressure of the pressure spring 9.

  The second pad 3b is made of a synthetic resin or metal having a hardness higher than that of the first pad 3a, and causes local strain in the elastic body layer 1c of the fixing roll 1 by being pressed against the fixing roll 1. It has become. In this portion, the moving speed of the peripheral surface of the fixing roll 1 locally increases, and a slight deviation occurs between the speed of the peripheral surface of the fixing roll 1 and the speed at which the recording paper P is conveyed. As a result, the recording paper P is easily peeled off from the fixing roll 1.

  The oil supply member 4 is made of a nonwoven fabric such as felt and is impregnated with a release agent such as silicone oil. The surface is supported in contact with the inner peripheral surface of the endless belt 2, and the release agent can be supplied to the inner peripheral surface of the endless belt 2.

  The sliding sheet 6 is made of a sheet-like member having a smooth surface, such as polyimide, or a woven fabric of fibers, such as polyimide. The end of the endless belt 2 in the circumferential direction is fixed to the pressure frame 8. The pressure pad 3 is wound around so as to be in contact with the inner peripheral surface of the endless belt 2. And the other edge part is not restrained but becomes a free end. Thus, the sliding sheet 6 is sandwiched between the pressure pad 3 and the inner peripheral surface of the endless belt 2 along the circumferential movement direction of the endless belt 2, and the inner peripheral surface of the endless belt 2 that moves in a circular motion is It is to be rubbed. The rubbing surface with the inner peripheral surface is subjected to surface treatment so as to reduce the frictional resistance, and the sliding resistance of the endless belt 2 due to the pressing of the pressure pad 3 is reduced.

  The pressurizing frame 8 is a beam-like member that is disposed inside the endless belt 2 and penetrates in the width direction of the endless belt 2, and includes a second pad 3b, an internal spring 7b, and a pad support member 7a. The first pads 3a are respectively supported through the intermediate pads. The pressure frame 8 is supported at both ends by the pressure lever 10, and the pressure pad 3 is moved through the endless belt 2 by the urging force of the pressure spring 9 that supports one end of the pressure lever 10. Pressing toward the fixing roll 1 side.

  As shown in FIG. 2, the pressure levers 10 are arranged on both sides in the width direction of the endless belt 2 along the conveyance direction of the recording paper P, and support both ends of the pressure frame 8 in the axial direction. is doing. The pressure lever 10 has one end located on the downstream side of the pressure contact portion between the fixing roll 1 and the endless belt 2, that is, on the downstream side in the conveyance direction of the recording paper P, on a frame (not shown) of the fixing device. The fixed stud 10a is attached so as to be rotatable about an axis. On the other hand, the upstream end of the pressure contact portion is supported by a pressure spring 9 and a fixing bolt 11, and the pressure spring 9 fixes the pressure pad 3 via a pressure lever 10 and a pressure frame 8. It is comprised so that it may press on the surrounding surface of the roll 2. FIG.

By adjusting the spring coefficients of the internal spring 7a and the pressure spring 9, the pressure contact force between the endless belt 2 and the fixing roll 1 and its distribution can be controlled.
In the present embodiment, the pressure pad 3 is divided into two parts in the circumferential movement direction of the endless belt 2, and each of the pressure pads 3 is independently displaced, and the first pad 3a on the upstream side is arranged. Although the internal spring 7a is inserted, the pressure pad 3 can be divided into three or more. However, it is desirable that a large difference in the pressure distribution does not occur in a certain range of the belt nip in the circumferential movement direction of the fixing roll 1 to prevent fixing unevenness.
Further, in the present embodiment, the fixing device constituted by the fixing roll 1 and the endless belt 2 has been described. However, a fixing device using a plurality of rolls and an endless belt stretched over these instead of the fixing roll. It may be.

Next, the operation of such a fixing device will be described below.
The recording paper P on which the toner image is transferred by a transfer device (not shown) is fed into a region where the fixing roll 1 and the endless belt 2 are in pressure contact, that is, a belt nip. At this time, the fixing roll 1 is driven to rotate, and the endless belt 2 also moves in accordance with the rotation. The leading edge of the recording paper P fed into the belt nip is located between the fixing roll 1 and the endless belt 2. It is sandwiched and pressed firmly against the fixing roll 1. The elastic layer 1c of the fixing roll 1 is deformed by the thickness of the recording paper P and the endless belt 2 is pressed from the back side while the leading edge of the recording paper P does not reach the downstream portion of the belt nip. The pad 3a is deformed, and the internal spring 7b and the pressure spring 9 that press the first pad 3a are deformed. However, the selection of the material of the first pad 3a or the spring coefficient of the internal spring 7b is set appropriately, so that the first pad 3a is easily displaced by the pressure contact force when the thick recording paper P is sandwiched, and is pressed. The amount of displacement by which the entire pad 3 moves backward is kept small.
Furthermore, since the fulcrum 10a of the pressure lever 10 is located on the downstream side of the belt nip, even if the pressure pad 3 is pushed down with the leading edge of the recording paper P entering the belt nip, the downstream side of the belt nip. Then, the displacement amount of the pressure pad 3 becomes small.

  Therefore, as shown in FIG. 3, even if the recording paper is sandwiched on the upstream side of the belt nip and the pressure contact force is transmitted from the pressure pad 3 to the fixing roll 1 through the recording paper, the recording paper P The pressure pad 3 presses the fixing roll 1 via the endless belt 2 on the downstream side of the belt nip where the leading end of the belt does not reach. For this reason, the pressing force transmitted from the pressure spring 9 to the pressure pad 3 via the pressure lever 10 is distributed and acts on the upstream side and the downstream side of the pressure pad 3 and moves toward the inlet side of the belt nip. Concentration of a large pressing force on the leading edge of the recording sheet P that has entered is reduced. As a result, local deformation of the elastic layer in the portion where the leading edge of the recording paper P is in contact with the fixing roll 1 is alleviated.

  As described above, when the leading edge of the recording paper P enters the belt nip, particularly when the thick recording paper P enters the belt nip, the load acting on the elastic body layer 1c of the fixing roll 1 is reduced. Therefore, when the elastic layer 1c of the fixing roll 1 has the surface release layer 1d as the outermost layer, damage to the surface of the fixing roll 1 is suppressed, and durability is improved.

  When the recording paper P is sandwiched in the belt nip as described above and conveyed and the leading edge reaches the downstream portion, the pressing force from the pressure pad 3 is distributed in the circumferential direction of the belt nip, and the recording paper P in a wide range. And the peripheral surface of the fixing roll 1 are pressed against each other. When the pressure contact force acts in a wide range, the toner image is sufficiently heated and pressed against the recording paper P, and good fixing is performed. Further, in the most downstream portion, the elastic layer 1c of the fixing roll 1 is greatly deformed by the second pad 3b, and a minute difference is generated between the peripheral surface speed of the fixing roll 1 and the conveyance speed of the recording paper P in this portion. The recording paper P is peeled from the fixing roll 1, and the recording paper P is sent out to a discharge path (not shown).

  In order to prevent the surface of the fixing roll 1 from being damaged by the leading edge of the recording paper P as described above, it is desirable to appropriately select the angle at which the recording paper P is fed into the belt nip. As shown in FIG. 4B, when the recording paper P is fed from the pressure member 2 side to the belt nip, the recording paper P protrudes toward the fixing roll 1 when the leading end is sandwiched in the belt nip. Bending deformation is generated. At this time, the upper side of the leading edge of the recording paper P is strongly pressed against the fixing roll 1. On the other hand, as shown in FIG. 4A, when the recording paper P is fed from the fixing roll 1 side, the recording paper P is bent and deformed in a convex shape on the pressing member 2 side. It is possible to reduce the load acting on the.

  The fixing device described above is an embodiment of the present invention. The present invention is not limited to this, and includes various forms having the configurations described in the claims.

1 is a schematic cross-sectional view illustrating a fixing device according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram illustrating a pressure contact mechanism between a fixing roll and a pressure pad in the fixing device illustrated in FIG. 1. FIG. 2 is an enlarged cross-sectional view illustrating a state when the recording paper enters a pressure contact portion between a fixing roll and a pressure pad in the fixing device illustrated in FIG. 1. FIG. 6 is a schematic diagram illustrating a relationship between an angle at which recording paper is fed to a pressure contact portion between a fixing roll and a pressure pad and a load acting on the surface of the fixing roll. FIG. 10 is an enlarged cross-sectional view illustrating a pressure contact portion between a fixing roll and a pressure pad in a conventional fixing device.

Explanation of symbols

1: fixing roll, 2: endless belt, 3: pressure pad, 3a: first pad, 3b: second pad, 4: oil supply member, 5a, 5b: guide member, 6: sliding sheet, 7a : Pad support member, 7b: internal spring, 7c: spring receiving member, 8: pressure frame, 9: pressure spring, 10: pressure lever, 10a: stud, 11: fixing bolt

Claims (4)

A fixing roll having an elastic layer on the outer peripheral surface and driven to rotate in a heated state;
An endless belt that is partly in contact with the peripheral surface of the fixing roll and supported so as to be capable of circular movement;
A pressure pad that is arranged along the axial direction of the fixing roll and presses the endless belt against the fixing roll from the inside of the endless belt;
A support member for supporting the pressure pad;
The support member is supported near both ends of the pressure pad in the axial direction of the fixing roll, one end of the endless belt in the circumferential movement direction is supported to be rotatable, and the other end is supported by the elastic member through the elastic member. A pressure lever for applying a pressing force to the fixing roll of the pressure pad,
A fixing device, wherein a recording medium having a toner image attached to a contact portion between the fixing roll and the endless belt is fed from an end portion where the pressure lever is supported via an elastic member. A fixing roll having an elastic layer on the outer peripheral surface and driven to rotate in a heated state;
An endless belt that is partly in contact with the peripheral surface of the fixing roll and supported so as to be capable of circular movement;
A pressure pad that is disposed along the axial direction of the fixing roll and presses the endless belt against the fixing roll from the inside of the endless belt;
The pressure pad is supported at both ends of the pressure pad in the axial direction of the fixing roll, one end of the endless belt in the circumferential movement direction is supported to be rotatable, and the other end is supported via an elastic member. A pressure lever for applying a pressing force to the fixing roll of the pressure pad,
In the vicinity of the edge on the inlet side of the recording medium in the circumferential movement direction of the endless belt, the pressure pad is more likely to be displaced from the outlet side due to the pressing force acting on the contact surface with the endless belt. A fixing device.   The pressure pad is divided into a plurality of portions arranged in a circumferential movement direction of the endless belt, and these portions can be independently displaced. The fixing device according to claim 2.   The portion provided on the most inlet side of the pressure pad is formed by the pressure lever via an elastic member that is deformed when a recording medium is fed between the fixing roll and the endless belt. The fixing device according to claim 3, wherein the fixing device is supported by the fixing device.

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