JPH1145018A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device of a belt nip system controlling the meandering of a endless-belt which uniformly applies a proper amount of lubricant to the inner circular surface of an endless belt by an extremely simple structure without causing trouble in the belt-meander control. SOLUTION: A lubricant application member 50 for applying the lubricant to the internal circular surface of the endless belt 30 while being in contact with the belt 30 is disposed between pressing support 20 and 21 so as to abut on the internal surface of the part of the endless belt 30 situated on the side of a fixing roll 10. The lubricant application member 50 is also disposed on the upstream side in the direction on the rotation of the belt of a pressure application member 40. Further, the pressure application member 40 is provided so as to be freely attachable/detachable. Also, on the pressure application member 40, the lubricant application member 50 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device of a belt nip type used for fixing an unfixed toner image formed in an image forming apparatus such as a copying machine or a printer using an electrophotographic system. It is.

[0002]

2. Description of the Related Art As a belt nip type fixing device of this type, for example, a fixing device having a structure as shown in FIG. 6 is known (Japanese Patent Application Laid-Open No. Hei 9-34291). this is,
A fixing roll 101 provided with a heating source 102 therein is rotatably disposed, and a plurality of support rolls 103 and 1 are provided.
The endless belt 106 stretched between the endless belts 04 and 105 is disposed so that a part of the outer peripheral surface of the belt is pressed against the fixing roll 101, and the belt portion is brought into contact with the inner peripheral surface of the endless belt 106 and the belt is A main part of the pressure applying member 107 that presses toward 101 is fixedly arranged. In this case, the endless belt 1
Reference numeral 06 is in contact with the fixing roll 101 by being supported by the support rolls 103 and 104, and is also in pressure contact with the fixing roll 101 by the pressure applying member 107. The area where the fixing roll 101 and the endless belt 106 are in contact is a nip (belt nip) N through which the recording sheet 109 carrying the unfixed toner image 108 is sandwiched. Reference numeral 110 in the drawing denotes a release agent application device that applies a release agent to the surface of the fixing roll.

In the fixing by the fixing device, the fixing roll 101 is heated and rotated, and the end belt 106 pressed against the fixing roll 101 is applied to the supporting rolls 103 to 105 by following the rotation of the fixing roll. The recording sheet 109 carrying the unfixed toner image 108 is carried into the nip N formed by the fixing roll 101 and the end belt 106 in this state. That is, as the recording sheet 109 passes through the nip, the unfixed toner is pressed and pressed to be fixed on the recording sheet 109.

In such a belt nip type fixing device, when the endless belt 106 is pressed against the fixing roll 101 by the pressure applying member 107 fixed and disposed as described above, the pressure application Endless belt 1 on which the pressing surface of member 107 rotates
06 is in sliding contact with the inner peripheral surface. Therefore, the pressure applying member 107 has a structure in which, for example, a surface of an elastic member 112 supported by a support plate 111 is covered with a low friction member 113 made of glass fiber or the like. It is configured to be used in a state where it is brought into contact with the device.

However, when the pressure applying member 104 having the low friction member 113 is used, the low friction member 113 gradually wears due to sliding contact with the inner peripheral surface of the endless belt 106, as shown in FIG. The wear (powder) 11
5 non-uniformly adheres to the inner peripheral surface of the belt 106 and the support roll. The arrows in the figure indicate the rotational movement direction of the belt. In addition, due to the attachment of the abrasion material, the sliding contact resistance between the pressure applying member 104 and the endless belt 106 gradually increases, and as a result, the smooth rotation characteristics of the belt 106 are also impaired, so that a fixed image can be formed. It can also have an adverse effect.

In a belt nip type fixing device,
Since the endless belt 106 may meander during rotation, for example, at least one support roll (corresponding to the support roll 105 in the illustrated apparatus) supporting the endless belt 106 has one end portion of the roll. The endless belt 106 is configured to be displaced in accordance with the meandering of the belt with the other end serving as a fulcrum, and the endless belt 106 is forcibly moved in one of left and right directions of its rotation to suppress meandering of the belt. . In the fixing device having such a meandering control support roll, the endless belt 106 and the pressure applying member 107 are caused to adhere to the inner peripheral surface of the belt and the support roll unevenly due to the aforementioned abrasion. And the frictional resistance between the endless belt 106 and the meandering control support roll 105 varies.
06 runs on one side in the axial direction of the support roll or the like, and the belt itself may be damaged. In addition, this endless belt 106
The uneven rotation may adversely affect the fixed image.

For this reason, conventionally, for example, as in a fixing device disclosed in the above-mentioned publication, a pressure applying member 10 is used.
A suitable amount of dimethyl silicone oil as a lubricant is applied to the surface of the low friction member 113 of No. 4 in advance, so that the abrasion resistance between the pressure applying member 104 and the endless belt 106 is reduced.

[0008]

However, in the case of a fixing device in which a lubricant is applied in advance to the surface of the low friction member 113 of the pressure applying member 104 as described above,
It is difficult to apply an appropriate amount of the lubricant to the surface member or the like of the pressure applying member 104, and the lubricant is applied under pressure by the pressure applying member 104. The following problems are likely to occur depending on excess or deficiency.

In other words, if the amount of the lubricant applied is too large, the support roll and the endless belt become slippery due to the excessively applied lubricant when the meandering control support roll is employed as described above. Therefore, even if the one end of the support roll is displaced, the belt does not move in a predetermined direction, so that there is a problem that belt meandering control cannot be performed.

On the other hand, if the amount of the lubricant applied is too small, the amount of the lubricant applied to the endless belt decreases in a short time, so that the frictional resistance between the pressure applying member and the endless belt gradually increases. In addition to hindering the smooth rotation of the belt, the abrasion of the pressure applying member progresses, and the worn material adheres unevenly to the inner peripheral surface of the belt and the support roll for meandering control as described above. However, there is a problem that normal belt meandering control cannot be performed due to the above, and the life of the pressure applying member is shortened due to the progress of wear, and the replacement of the pressure applying member must be performed early.

Japanese Patent Application Laid-Open No. Hei 3-210588 discloses a heat-resistant film that is rotatably supported.
A fixing device of a type provided so as to pass between a fixedly supported heating element and a pressure roll, and fixing by passing a recording sheet carrying an unfixed toner image between the film and the pressure roll. In the method, as a means for applying a lubricant to the inner peripheral surface of the film, a lubricant in a tank is applied between a driven support roll and a heating body via an application roller which rotates while being in contact with the inner peripheral surface of the film. (4th configuration)
(FIG. 5) and a configuration in which the lubricant in the tank is supplied through a perforated film from an opening formed in a part of the contact surface of the heating element with the heat-resistant film (FIG. 5).

However, in the former case, since the coating roller is disposed at the place where the ripples occur on the film surface, a pressing member is further required when the coating roller is brought into uniform contact with the film. This leads to an increase in the size of the device. Also, it is difficult to replace the application roll. The latter has a complicated structure, and it is difficult to replace a coating portion provided on a part of the heating body.

The present invention has been made in view of such circumstances of the prior art, and has as its object the purpose of a belt nip type fixing device for controlling meandering of an endless belt with a very simple configuration. Accordingly, it is an object of the present invention to provide a fixing device capable of uniformly and appropriately applying a lubricant to an inner peripheral surface of an endless belt so as not to hinder belt meandering control.

Another object of the present invention is to provide a fixing device that can apply the lubricant more uniformly and stably in a more effective place without hindering the fixing operation.

Another object of the present invention is to provide a fixing device capable of efficiently and easily replacing the lubricant applying means at an appropriate timing.

[0016]

According to the fixing device of the present invention, a rotating fixing roll and a recording sheet carrying an unfixed toner image by pressing the outer peripheral surface of the belt against the fixing roll are sandwiched between the fixing roll. Two or more pressure-contact support rolls that are supported from the inner peripheral surface side of the belt so as to form a nip to be formed, and a belt portion located on the opposite side of the fixing roller from the pressure-contact support roller is supported from the inner peripheral surface side of the belt. And an endless belt stretched over one or more meandering control support rolls displaced so as to suppress meandering of the belt, and a predetermined range of a portion forming the nip of the endless belt is fixed to the fixing roll. Assuming that the fixing device includes a pressure applying member that contacts and presses from the inner peripheral surface side of the belt, a lubricant is applied in contact with the inner peripheral surface of the endless belt. The lubricant application member fit, but provided so as to contact the inner circumferential surface of the endless belt portion located on the fixing roller side between the pressure-contact support roll.

In the apparatus having such a configuration, the lubricant application member is an endless belt portion that is stretched between two or more pressure-contacting support rolls for forming a nip, and the belt meandering control is performed. Since the waviness of the belt surface caused by the above will contact the inner peripheral surface of the endless belt part which is the least (absorbed by the support roll part and disappears), uniform and stable application of lubricant is possible Becomes This also ensures proper application of the lubricant.

Further, in the fixing device of the present invention, in the above-mentioned device of the present invention (main invention), a lubricant application member is provided upstream of the pressure applying member in the belt rotation direction.

In the apparatus having such a configuration, since the lubricant applying member comes into contact with the inner peripheral surface of the endless belt, which is in front of the nip, the lubricating member affects the fixing operation as compared with, for example, the case where the lubricant is applied inside the nip. There is no possibility of giving (fixed image disturbance due to contact fluctuation of the coating member). Further, the lubricant applied to the belt from the lubricant applying member is reliably supplied without loss between the pressure applying member and the endless belt.

Further, in the fixing device of the present invention, in the above-described main device of the present invention, the pressure applying member is detachably provided, and the pressure applying member is provided with the lubricant applying member. Things.

In the device having such a configuration, since the lubricant applying member is attached to and detached from the pressure applying member, the replacement operation can be easily performed. In addition, the time when the lubricant application member should be replaced is the time when the amount of the lubricant decreases over time, and the time when the pressure applying member starts to be worn due to the decrease in the lubricant. And the replacement time of the pressure applying member substantially coincide with each other. As a result, when performing the replacement work of the lubricant application member,
Along with the attachment / detachment being performed integrally with the pressure applying member, the replacement operation of the pressure applying member can also proceed at the same time.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a fixing device according to an embodiment of the present invention. The fixing device is, for example, an image forming apparatus such as a copying machine or a printer (not shown) using an electrophotographic system. It is used by being incorporated in The fixing device includes a heat fixing roll 10 having a built-in heating source, an endless belt 30 stretched over three support rolls 20, 21, 22 and pressed against the heat fixing roll 10, and a predetermined fixing of the endless belt 30. The pressure applying member 40 that contacts and presses the area from the inner peripheral surface side of the belt toward the fixing roll 10, and the lubricant applying member 50 that applies lubricant by contacting the inner peripheral surface of the endless belt 30. The main part is configured.

The heat-fixing roll 10 includes a cylindrical cored bar 11 made of a metal having a high thermal conductivity such as aluminum, a base layer 12 made of an elastic material, and an elastic material excellent in heat resistance. And a roll structure in which a surface layer 13 composed of A halogen lamp 14 as a heating source is arranged inside the cylinder of the metal core 11. On the surface of the heat fixing roll 10, a temperature sensor 15 for measuring the surface temperature of the roll is arranged.

The heat-fixing roll 10 is rotatably supported by a support mechanism (not shown) and is rotated at a predetermined speed in a direction indicated by an arrow in the figure by a drive unit (not shown). The halogen lamp 14 is feedback-controlled by a temperature controller (not shown) based on a measurement signal from the temperature sensor 15, so that the surface of the fixing roll is maintained at a predetermined temperature.

A release agent supply device 17 is provided around the heat fixing roll 10. The release agent supply device 17 is provided with a sponge-like suction member 17b, rolls 17c and 17 from a tank 17a for storing an oil release agent.
A fixed amount of the release agent is supplied to the surface of the heat fixing roll 10 through d. 17e is a scraper blade for contacting the roll 17c and keeping the amount of the release agent adhered to the roll 17c. This prevents a part of the toner 2 from being offset to the heat-fixing roll when the image of the unfixed toner 2 is fixed on the recording sheet 1.

Further, a web type cleaning device 18 is provided around the heat fixing roll 10. The cleaning device 18 is configured such that a web member 18b made of a nonwoven fabric or the like sent from a delivery roll 18a is brought into contact with the surface of the fixing roll 10 by a pressing roll 18c and then wound up by a predetermined amount by a winding roll 18d. To remove toner, paper powder, etc. adhering to the surface of the substrate. This keeps the surface of the fixing roll 10 clean at all times.

The endless belt 30 is formed of a resin film such as a polyimide film, and has three support rolls 20, 21, and rotatably supported.
It is installed in a state of being wrapped around 22.

The support roll 20 is rotatably disposed at a position downstream of the lowermost point of the heating and fixing roll 10 in the rotation direction while being pressed against the heating and fixing roll 10 by a pressing mechanism (not shown). Roll. The support roll 21 is a roll rotatably disposed at a position slightly away from the lowermost point of the fixing roll 10 toward the upstream side in the horizontal direction. Further, the support roll 22 has one end 22a of the roll shaft mounted on a bearing 24 rotatably disposed about a support shaft 23, and the other end 22b of the roll shaft is horizontally moved by a displacement drive mechanism (not shown). It is attached to a bearing 25 arranged so as to move back and forth (directions of arrows E and F) in the direction (see FIG. 4). The support roller 22 is moved in a direction in which the displacement drive mechanism is feedback-controlled by a drive controller that operates based on a detection signal from a sensor (not shown) that detects the meandering traveling of the endless belt, and the meandering of the belt is suppressed. It is configured to move by a fixed amount.

Therefore, the endless belt 30
The support belt is stretched with a predetermined tension on one support roll. In particular, the two support rolls 20 and 21 are arranged so that the outer peripheral surface of the belt is pressed against the surface of the heat fixing roll 10 by a predetermined amount. As a result, the recording sheet 1 carrying the unfixed toner image 2
And a nip N sandwiched therebetween. In addition, the support rolls 22 support the support rolls 20.
The endless belt 30 located on the side opposite to the fixing roll 10 from the support roll 21 is supported, and meandering of the belt is suppressed.

On the upstream side of the support roll 21, there is provided a guide member 28 for guiding the recording sheet 1 carrying the unfixed toner image 2 to the nip N. Further, on the downstream side of the support roll 20, a guide member 29 that guides the recording sheet 1 that has passed through the nip N and is separated from the fixing roll 10 to be discharged is provided.

As shown in FIGS. 2 and 3, the pressure applying member 40 includes a support member having a divided structure of a support plate 41 and a support plate receiver 42, both of which are formed of stainless steel or the like and whose upper surface is smooth. An elastic layer 43 made of silicone rubber (rubber hardness 23 °) attached to the upper surface of a support plate 41 of a support material, and a glass fiber sheet impregnated with polytetrafluoroethylene (FGF-40 manufactured by Chuko Kasei)
The main part is constituted by the low friction layer 44 composed of 0-4). The illustration of the low friction layer 44 is omitted in FIG.

The support plate 41 has a T-shaped cross section, and the lower surface of the support plate 41 has a ridge 4 extending along the axial direction of the fixing roll 10.
1a is formed. The support plate receiver 42 has an upper surface formed with a concave groove 42a into which the protruding ridge 41a on the lower surface of the support plate 41 is fitted, and an extended portion 42b formed at a portion except for both ends of the lower surface. Have been. The elastic layer 43 is formed in a curved shape such that the upper surface thereof is along the surface of the fixing roll 10, and is formed so as to extend to near a contact portion between the support roll 20 and the fixing roll 10. Thus, the endless belt 30 can be securely adhered along the surface of the fixing roll 10 within the range where the nip N is formed. The low friction layer 44 is attached in a state in which the support plate 41, the support plate receiver 42, and the elastic layer 43 are integrated and wound around the entire periphery of the integrated body.

Further, as shown in FIG. 3, the pressure applying member 40 includes a support plate 4 on which an elastic layer 43 is attached.
1 is fitted to the support plate receiver 42, integrated with screws 44 and the like, and then detachably attached to the pair of left and right pressure frames 45. The pressure frame 45 has a support plate receiver 4
2 (without the protruding portion 43) is formed with a locking concave portion 45a for fitting and locking the end portion 42c, and the other end side has a shaft hole 45b formed on a support shaft (not shown) of the fixing device main body. Is mounted so as to be swingable via a locking recess 45a.
The lower side of the fixing roller 10 is fixed by the coil spring 46.
To be biased at a predetermined pressure.

The pressure applying member 4 to the pressing frame 45
In order to attach 0, the pressing frame 45 is first pressed down against the urging force of the coil spring 46,
The end portion 42c of the support plate receiver is fitted and locked in the locking concave portion 45a in that state, and thereafter, the force for pushing down the pressing frame 45 is removed. Accordingly, the pressure applying member 40 is rotated by the coil spring 46 about the shaft hole 45 b as a fulcrum, and is pressed against the surface of the fixing roll 10 via the endless belt 30 with a predetermined pressure. On the other hand, the removal can be performed by bringing the pressing frame 45 into a depressed state and then pulling out the end 42c of the support plate receiver from the locking recess 45a in that state.

The lubricant applying member 50 is impregnated with a lubricant, and is in contact with the inner peripheral surface of the endless belt 30. A holding member 51 holding the impregnating member 51 is formed of metal, synthetic resin, or the like. The main part is constituted by the member 52. As the impregnating member 51, for example, a felt having a thickness of about 1 to 5 mm impregnated with dimethyl silicone oil (viscosity 10 cs) as a release agent (Shin-Etsu Chemical Co., Ltd.)
Manufactured by Nomex KF96), but is not limited thereto, and any flexible member that can be impregnated with a lubricant can be used.

The lubricant applying member 50 is detachably attached to the upstream side of the pressure applying member 40 in the belt rotation direction, specifically, to the side surface of the support plate 41 (or its receiver 42) with a screw 53 or the like. Attached to. At this time, the height of the upper end of the impregnating member 51 is
(0 mm means the same height) with a difference of about 0 to 5 mm with respect to the height of the upper surface portion. Thereby, the lubricant application member 50
The upper end of the impregnating member 51 is
Is maintained in a state of contact with the inner peripheral surface.

Next, the operation of the fixing device will be described.

First, when the surface of the heat fixing roll 10 reaches a predetermined temperature by heating the halogen lamp 14 and a start signal of an image forming operation (copying operation, printing operation, etc.) in an image forming apparatus (not shown) is received.
In the image forming apparatus, a toner image 2 is formed on a recording sheet 1.
Is transferred and the recording sheet 1 is conveyed to the fixing device. In synchronization with the start of the image forming operation, the heat fixing roll 10 starts to rotate in the direction of the arrow in FIG.
In the state of being stretched between 1 and 23, it starts rotating in the direction of the arrow in FIG.

The rotation of the heat-fixing roll 10 causes the release agent to be applied to the surface of the roll by the release agent supply device 17, and unnecessary substances such as residual toner adhering to the roll surface are removed by the cleaning device 18. Removed.

On the other hand, the endless belt 30 at this time is
Are the support by the support rolls 20 and 21 and the pressure applying member 4
Due to the pressing by 0, the rotation is performed in a state where a nip N is formed between the heating fixing roll 10 and the heat fixing roll 10. A lubricant is applied to the inner peripheral surface of the endless belt 30 by a lubricant applying member 50 on the upstream side in the belt rotation direction of the pressure applying member 40. As a result, since the lubricant is supplied between the endless belt 30 and the pressure applying member 40, the frictional resistance between the belt 30 and the pressure applying member 40 is reduced, and the low friction layer in the pressure applying member 40 is reduced. 44
Is prevented from being worn.

When the recording sheet 1 carrying the toner image 2 is carried into the nip N and passes therethrough, the toner constituting the toner image 2 is heated and pressed to be fixed on the recording sheet 1. You. After passing through the region of the elastic layer 12 of the fixing roll 10 which is elastically deformed by the pressing by the support roll 20, the recording sheet 1 after the fixing process is naturally separated from the surface of the fixing roll 10 without using a peeling device. (So-called self-stripping),
It is discharged to the subsequent process.

In this fixing device, when the endless belt 30 meanders, as shown in FIG.
In order to suppress the meandering, the support roll 22 for meandering control is displaced. For example, when the belt 30 travels in a meandering manner in the direction of arrow H, the roll end 22b of the support roll 22 is moved by a predetermined amount in the direction of arrow F with the support shaft 23 of the bearing 24 as a fulcrum. As a result, the support rolls 2 and 21 with their axes parallel to each other
Since only 2 is inclined, the endless belt 30
Moves while rotating in the direction of arrow G, thereby eliminating the meandering. Conversely, when the belt 30 travels meandering in the direction of arrow G, the roll end 22b is moved by a predetermined amount in the direction of arrow G.

In the case of this fixing device, the lubricant applying member 50
The (impregnating member) is disposed so as to abut on the inner peripheral surface portion of the endless belt between the support roll 21 and the pressure applying member 40, and this belt portion controls the meandering of the belt as described above. Is the surface having the least amount of waviness when the process is performed, and therefore the upper end portion of the impregnating member is easily brought into uniform contact with the inner peripheral surface of the belt. Moreover, the impregnating member 51
Is a flexible felt member, so that even if there is some fluctuation in the belt, it comes into contact so as to reliably follow the belt fluctuation. As a result, the lubricant impregnated in the impregnating member 51 of the lubricant applying member 50 is always supplied to the inner peripheral surface side of the belt by a constant amount. As long as the lubricant in the impregnating member 51 remains, smooth rotation of the end belt 30 can be ensured, and the pressure applying member 4
The wear of the low friction layer 44 can be suppressed.

In this fixing device, since the lubricant applying member 50 is provided upstream of the pressure applying member 40 in the belt rotation direction, the lubricant applied from the applying member 50 to the inner peripheral surface of the belt is provided. The agent is reliably supplied between the pressure applying member 40 and the endless belt 30 (within the nip N) without loss (without being reduced by adhering to the support roll). Thus, the endless belt 30 rotates stably without being changed by the pressing by the pressure applying member 40. In addition to the stable rotation of the endless belt 30, the endless belt 30 is reliably kept in close contact with the fixing roll 10 in the nip N to the support roll 20 by the pressure applying member 40, so that the nip Since the recording sheet 1 passing through N always passes in a constant state, the fixed image is not disturbed.

Further, the lubricant applying member 50 is replaced at a time when the amount of the lubricant impregnated in the impregnating member 51 becomes low. Also, when this lubricant is low,
Since the amount of the lubricant applied to the inner peripheral surface of the endless belt 30 is reduced, and the time when the low friction layer 44 of the pressure applying member 40 starts to wear substantially coincides with the time, the pressure applying member 40
This almost corresponds to the replacement period. In the case of this fixing device, since the lubricant applying member 50 is attached to the pressure applying member 40, by removing the pressure applying member 40, the lubricant applying member 50
Can be removed at the same time, so that both the removal work, the replacement work, and the attachment work can be performed at the same time, thus ensuring extremely efficient workability.

FIG. 5 shows another embodiment of the pressure applying member 40 and the lubricant applying member 50. This is because the width of the elastic layer 43 in the pressure applying member 40 in the endless belt rotation direction is reduced on the upstream side, and the lubricant application member 5
0, the upper end 51a of the impregnating member 51 is
3, except that the fixing device is bent as much as possible.

With this configuration, the contact area of the impregnating member 51 of the lubricant applying member 50 with the endless belt 30 is increased, so that the lubricant can be more uniformly applied to the inner peripheral surface of the belt. Even if the belt fluctuates, the lubricant can be applied uniformly.

The lubricant application member 5 according to the present invention
0 indicates that the support roll 20 is provided at a position such as the fixing device shown in FIG.
May be disposed so as to abut on the inner peripheral surface of the endless belt portion between the support roll 104 and the pressure applying member 107.

When a fibrous material such as a filter is used as the impregnating member 51 in the lubricant applying member 50, the fibrous material is worn by the sliding contact of the impregnating member 51 with the endless belt 30. The surface of the fibrous impregnated member is baked or the sliding contact with the endless belt 30 is covered with a permeable thin sheet material such as a nonwoven fabric in order to prevent the material from falling off and falling off. You may do so. Thereby, it is possible to reliably prevent the abrasion powder and the dropped fibers of the fibrous impregnating member 51 from adhering to the inner peripheral surface of the endless belt and each support roll.

Further, in the above-described embodiment, since the pressure distribution of the pressure applying member 40 in the axial direction of the fixing roll 10 is made uniform, the support member of the pressure applying member 40 can prevent warpage during cutting. From the viewpoint, a divided structure including the support plate 41 and the support plate receiver 42 is adopted, but a structure in which both are integrated may be used.

Further, as the pressure applying member 40, a roll type which rotates or a tube type which elastically deforms may be used.

[0053]

As described above, according to the first aspect of the present invention, the lubricant application member abuts on the inner peripheral surface of the endless belt portion located on the fixing roll side between the press-contact support rolls. With such a configuration, the lubricant can be applied to the inner peripheral surface of the belt in an appropriate amount and uniformly so as not to hinder belt meandering control. In addition, since the lubricant applying member has a very simple configuration, the fixing device does not needlessly become large. Therefore, when this fixing device is used, the endless belt can be rotated stably, the abrasion of the pressure applying member is small, and the belt meandering control can be performed reliably, so that better fixing can be performed. become.

According to the second aspect of the present invention, since the lubricant applying member is provided on the upstream side of the pressure applying member in the belt rotation direction, disturbance of the fixed image is not induced, and the lubricant is applied under pressure. It can be supplied uniformly and stably without loss between the member and the endless belt.

Further, according to the third aspect of the present invention, the pressure applying member is detachably provided, and the pressure applying member is provided with the lubricant applying member.
The lubricant application member can be efficiently and easily replaced together with the pressure applying member at an appropriate timing. In this case, the exchangeability of the fixing device is improved.
The assemblability is also improved, and the installation space for the lubricant application member can be saved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration of a main part of a fixing device according to an embodiment of the present invention.

FIG. 2 is an explanatory sectional view showing a configuration of a pressure applying member.

FIG. 3 is an explanatory exploded view of a main part showing each configuration of a pressure applying member and a lubricant applying member.

FIG. 4 is an explanatory view showing the principle of a belt meandering control mechanism.

FIG. 5 is an explanatory cross-sectional view showing another configuration of the pressure applying member.

FIG. 6 is a schematic diagram showing a conventional belt nip type fixing device.

FIG. 7 is an explanatory view showing a phenomenon of attachment of a wear object.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording sheet, 2 ... Unfixed toner image, 10 ... Heat fixing roll, 20, 21 ... Support roll (pressing support roll), 22 ... meandering control support roll, 30 ... Endless belt, 40 ... Pressure applying member , 50 ... lubricant application member,
N ... Nip.

Claims (3)

[Claims] An inner peripheral surface of a belt is formed so that a recording sheet carrying an unfixed toner image is sandwiched between the rotating fixing roller and the fixing roller by pressing an outer peripheral surface of the belt against the fixing roller. Two or more pressure-contact support rolls supported from the side, and a belt portion positioned on the opposite side from the pressure-contact support roll to the fixing roll is supported from the belt inner peripheral surface side and displaced so as to suppress meandering of the belt. An endless belt stretched over one or more meandering control support rolls, and a predetermined range of a portion forming the nip of the endless belt is brought into contact with the fixing roll from the inner peripheral surface side of the belt. A pressure applying member for pressing, wherein a lubricant applying member for applying a lubricant in contact with an inner peripheral surface of the endless belt is provided by the pressing contact support. A fixing device, characterized in that provided so as to contact the inner circumferential surface of the endless belt portion located on the fixing roller side between the rolls. 2. The fixing device according to claim 1, wherein the lubricant applying member is provided upstream of the pressure applying member in a belt rotation direction. 3. The fixing device according to claim 1, wherein the pressure applying member is detachably provided, and the pressure applying member is provided with the lubricant applying member.