JP6907590B2 - Fixing device - Google Patents

Description

In the present invention, an endless belt, an opposing member that contacts the outer peripheral surface of the belt, a rotating member that contacts the inner peripheral surface of the belt and sandwiches the belt between the opposing members, and an inner peripheral surface and sliding of the belt. The present invention relates to a fixing device including a sliding contact member in contact with the sliding contact member.

In the fixing device of the image forming apparatus, a pressure belt method is known in which an endless belt is sandwiched between facing members such as a heating member and a pressure member and rotated.

As such a pressure belt type fixing device, for example, in Patent Document 1, between an endless belt, a heating roller in contact with the outer peripheral surface of the belt, and a heating roller in contact with the inner peripheral surface of the belt. In order to improve the slidability between the pressure roller that sandwiches the belt, the pressure pad that slides against the inner peripheral surface of the belt and presses the belt against the heating roller, and the inner peripheral surface of the belt and the pressure pad, A configuration including an oil coating roller for applying a lubricant to the inner peripheral surface is disclosed.

JP-A-2007-79067

In the fixing device disclosed in Patent Document 1, since the oil coating roller is provided separately from the pressurizing roller, the number of parts increases and the manufacturing cost of the fixing device increases.

Therefore, an object of the present invention is to stably apply the lubricant to the inner peripheral surface of the belt without increasing the number of parts in the fixing device.

In order to solve the above problems, the fixing device according to the present invention has an endless belt, an opposing member that contacts the outer peripheral surface of the belt, and an opposing member that contacts the inner peripheral surface of the belt and sandwiches the belt between the opposing members. Includes a rotating member and a sliding contact member that is in sliding contact with the inner peripheral surface of the belt.
The rotating member is characterized in that a first porous portion impregnated with a lubricant is provided at a portion in contact with the inner peripheral surface of the belt.

According to this configuration, it is not necessary to provide a member for applying the lubricant to the inner peripheral surface of the belt separately from the rotating member, so that the lubricant is applied to the inner peripheral surface of the belt without increasing the number of parts. This makes it possible to reduce the sliding resistance between the sliding contact member and the inner peripheral surface of the belt.

According to the present invention, in the fixing device, the lubricant can be stably applied to the inner peripheral surface of the belt without increasing the number of parts.

It is sectional drawing which shows the whole structure of the laser printer as an example of an image forming apparatus. It is sectional drawing which shows the structure of the fixing device which concerns on embodiment of this invention. (A) is a cross-sectional view showing the structure of a pressure roller and the positional relationship with respect to a pressure pad, and (b) is a partially enlarged view of (a). (A) is a cross-sectional view of a pressure roller according to a first modification, and (b) is a partially enlarged view of (a). (A) is a cross-sectional view of a pressure roller according to a second modification, and (b) is a partially enlarged view of (a).

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the following description, the direction will be described in the direction shown in FIG. That is, in FIG. 1, the right side facing the paper is the "back side", the left side facing the paper is the "front side", the back side facing the paper is the "left side", and the front side facing the paper is the "right side". And. In addition, the vertical direction is defined as the "vertical direction" toward the paper surface.

As shown in FIG. 1, the laser printer 1 has a paper feed unit 3 for feeding paper P as a recording sheet, an exposure device 4, and a toner image (development) on the paper P in the main body housing 2. It mainly includes a process cartridge 5 for transferring the agent image) and a fixing device 6 for thermally fixing the toner image on the paper P.

In the paper feed unit 3, the paper P in the paper feed tray 31 is brought to the paper feed roller 33 side by the paper pressing plate 32 and sent out by the paper feed roller 33 and the paper feed pad 34, and the process described later one by one. It is conveyed to the cartridge 5.

The exposure device 4 is provided in the upper part of the main body housing 2, and mainly includes a laser emitting unit (not shown), a polygon mirror 41 that is rotationally driven, lenses 42, 43, and reflectors 44, 45, 46. Be prepared for.

The process cartridge 5 is provided below the exposure apparatus 4 and has a structure in which the process cartridge 5 is detachably attached to the main body housing 2. The process cartridge 5 includes a hollow cartridge frame 51 that constitutes an outer frame. The process cartridge 5 further includes a photosensitive drum 52, a scorotron type charger 53, a transfer roller 54, and a developing cartridge 55 in the cartridge frame 51.

The developing cartridge 55 is detachably attached to the cartridge frame 51, and includes a developing roller 56, a layer thickness regulating blade 57, a supply roller 58, and a toner accommodating portion 59.

The photosensitive drum 52 is rotatably supported by the cartridge frame 51. The photosensitive drum 52 has a drum body grounded and a surface portion formed of a positively charged photosensitive layer.

The transfer roller 54 is rotatably supported by the cartridge frame 51 below the photosensitive drum 52, and is arranged so as to face and contact the photosensitive drum 52. A transfer bias is applied to the transfer roller 54 during transfer.

In the process cartridge 5 configured in this way, the surface of the photosensitive drum 52 is uniformly positively charged by the scorotron type charger 53, and then exposed by high-speed scanning of the laser beam from the exposure apparatus 4. As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed.

Next, when the photosensitive drum 52 and the developing roller 56 face each other due to the rotation of the developing roller 56, the toner carried on the developing roller 56 is electrostatically latent formed on the surface of the photosensitive drum 52. Supplied to the statue. In this way, the toner is selectively supported on the surface of the photosensitive drum 52 to visualize the electrostatic latent image, and the toner image is formed by reverse development.

Then, the photosensitive drum 52 and the transfer roller 54 rotate so as to sandwich and convey the paper P between them, and the paper P is conveyed between the photosensitive drum 52 and the transfer roller 54, so that the photosensitive drum 52 is conveyed. The toner image supported on the surface is transferred onto the paper P.

The fixing device 6 is provided on the back side of the process cartridge 5 (downstream side in the transport direction of the paper P), and includes a heating roller 61, an endless belt 62, and a pressure roller 63 pressed toward the heating roller 61. Mainly equipped with. Further, on the downstream side of the paper P of the fixing device 6 in the transport direction, paper ejection rollers 71 and 72 and a paper ejection path 73 for discharging the paper P conveyed from the fixing device 6 to the outside of the main body housing 2 are provided. Has been done.

In the fixing device 6 configured as described above, the toner image transferred on the paper P is heat-fixed while the paper P passes between the heating roller 61 and the belt 62 hung on the pressure roller 63. .. After that, the paper P is conveyed to the paper ejection path 73 by the paper ejection roller 71, and is ejected from the paper ejection path 73 onto the paper ejection tray 74 by the paper ejection roller 72.

Hereinafter, the outline of the fixing device 6 and the details of the pressure roller 63 will be described with reference to FIGS. 2 and 3.
As shown in FIG. 2, the fixing device 6 comes into contact with the heating roller 61 as an example of the opposing member, the endless belt 62, and the inner peripheral surface of the belt 62, and holds the belt 62 between the heating roller 61. A pressure roller 63 as an example of a rotating member to be sandwiched, and a belt guide 67 and a pressure pad 69 as an example of a sliding contact member that is in sliding contact with the inner peripheral surface of the belt 62 are provided.

The heating roller 61 is formed in a cylindrical shape, and is configured such that the surface is heated to a fixing temperature by a heat source H such as a halogen heater provided inside. Further, both ends of the heating roller 61 projecting outward in the axial direction are rotatably supported by a frame (not shown).
The heating roller 61 is rotationally driven by transmitting a driving force (not shown) provided in the main body housing 2, and is brought into contact with the outer peripheral surface of the belt 62 to bring the belt 62 together. Rotate around.

The belt 62 is wound around the pressure roller 63, the belt guide 67, and the pressure pad 69. The belt 62 rotates by rotating with the heating roller 61 and the pressure roller 63 while sliding contact with the belt guide 67 and the pressure pad 69.
The belt 62 can be formed by, for example, forming a film of a heat-resistant resin such as polyimide (PI), an electroformed film of nickel, an electroformed film of stainless steel, or the like in an endless manner.

The belt guide 67 is a member that extends along the axial direction of the heating roller 61, guides the inner peripheral surface of the rotating belt 62, and supports the pressure pad 69 via the support member 68.
The belt guide 67 is arranged on the side opposite to the pressure roller 63 with respect to the pressure pad 69, and guides the belt 62 by sliding contact with the inner peripheral surface of the belt 62.
The belt guide 67 is made of a material having a small coefficient of friction with the inner peripheral surface of the belt 62, and has a curved outer peripheral portion 67A that is in sliding contact with the inner peripheral surface of the belt 62 and a support member 68 that supports the pressure pad 69. It has a fixing surface 67B to be fixed.

The pressure pad 69 sandwiches the belt 62 with the heating roller 61 by pressing the belt 62 against the heating roller 61. The pressure pad 69 is a member for increasing the nip width n together with the pressure roller 63 and increasing the contact area between the heating roller 61 and the paper P to increase the heat fixing speed.
The pressure pad 69 extends along the axial direction of the heating roller 61 and is fixed to the surface of the support member 68. The pressure pad 69 is made of an elastic material having a small coefficient of friction with the inner peripheral surface of the belt 62.

The pressure roller 63 comes into contact with the inner peripheral surface of the belt 62 and presses the belt 62 against the heating roller 61 to sandwich the belt 62 with the heating roller 61. When the heating roller 61 is rotationally driven, the pressure roller 63 rotates along with the belt 62.

As shown in FIGS. 3A and 3B, the pressure roller 63 includes a roller portion 63A and a rotating shaft 63B.
Specifically, the roller portion 63A is made of an elastic layer that covers the periphery of the rotating shaft 63B. The rotating shaft 63B is a metal rod-shaped member, and both ends thereof project outward in the axial direction from both ends of the roller portion 63A and are rotatably supported by a frame (not shown). The rotating shaft 63B may be a rod-shaped member that penetrates the roller portion 63A, or may be two protrusions that protrude from both ends in the axial direction of the roller portion 63A without penetrating the roller portion 63A.
Further, on the outer peripheral surface of the roller portion 63A, the first porous layer 64, the two second porous layers 65, and the two resistance layers 66 are in contact with each other at the points where they come into contact with the inner peripheral surface of the belt 62. It is provided in a state of being. The first porous layer 64 is an example of the first porous portion, the second porous layer 65 is an example of the second porous portion, and the resistance layer 66 is an example of the resistance portion.

The first porous layer 64 is a layer for applying a lubricant to the inner peripheral surface of the belt 62 in order to reduce the sliding resistance between the belt guide 67 and the pressure pad 69 and the belt 62.
Specifically, the first porous layer 64 is formed by impregnating the porous layer of a continuous cell structure having a thickness of several μm provided at the axial center portion of the roller portion 63A with a lubricant, and the belt 62. When it comes into contact with the resistance layer 66 and rotates, it receives pressure from the heating roller 61 and is crushed to apply a lubricant to the inner peripheral surface of the belt 62. Therefore, in a state where no pressure is applied between the pressure roller 63 and the heating roller 61, at least a part of the surface of the first porous layer 64 is radially outside the pressure roller 63 with respect to the surface of the resistance layer 66. It is formed to be located in. More specifically, the thickness T0 of the roller portion 63A (distance from the outer peripheral surface of the rotating shaft 63B to the outer peripheral surface of the roller portion 63A) is uniform in the axial direction, whereas the thickness of the first porous layer 64 is uniform. T1 is formed thicker than the thickness T5 of the resistance layer 66.
The "state in which no pressure is applied between the pressure roller 63 and the heating roller 61" means a state in which the entire surface of the pressure roller 63 is not crushed before the pressure roller 63 is assembled. do. Further, even after the pressure roller 63 is assembled, as shown in FIG. 2, the portion of the entire surface of the pressure roller 63 that is not in contact with the inner peripheral surface of the belt 62 is not crushed. Means the state.

Further, in the axial direction of the pressure roller 63 (hereinafter, simply referred to as "axial direction"), the first porous layer 64 has a width W1 equal to or larger than the width of the minimum size paper P that can be used in the laser printer 1. ing. Further, the width W1 of the first porous layer 64 is equal to or wider than the width W2 of the pressure pad 69, and both ends of the first porous layer 64 are outside the both ends of the pressure pad 69. It is arranged so as to protrude.

The first porous layer 64 is, for example, a PEEK (polyetheretherketone) resin, a PPS (polyphenylene sulfide) resin, a silicone resin, a fluororesin (PTFE, PFA, FEP, EEFT), an imide resin (polyimide, polyamideimide). , Polyetherimide), PBI (polybenzoimidazole) resin, composed of a heat-resistant resin composed of a single material or a plurality of materials.

Further, since the first porous layer 64 is impregnated with a lubricant, it has a plurality of voids having a cell diameter of 0.1 μm or more and several tens of μm or less. The plurality of voids are dispersed substantially uniformly throughout the first porous layer 64.
The first porous layer 64 is, for example, coated with the roller portion 63A with the above-mentioned solution containing the resin material, and is vaporized by evaporating the solvent in the solution by firing or air-drying to make the porous layer appear, and then lubricated. It is formed by impregnating the material.

A known lubricant can be used as the lubricant, but the lubricant is determined in consideration of the combination with the heat-resistant resin constituting the first porous layer 64.
Specifically, when the first porous layer 64 is composed of a silicone resin, a lubricant other than silicone oil is used as the lubricant. Similarly, when the first porous layer 64 is composed of a fluorine-based resin, a lubricant other than the fluorine-based lubricant is used.

The second porous layer 65 is provided on both sides of the first porous layer 64 in the axial direction, and is a layer for absorbing the lubricant flowing outward in the axial direction from the first porous layer 64.
The second porous layer 65 is a porous layer of an open cell structure like the first porous layer 64, and has a thickness substantially equal to the thickness T1 of the first porous layer 64. Two second porous layers 65 are provided outside the first porous layer 64 in the axial direction.
The second porous layer 65 is formed by appropriately selecting from the same resin materials as the first porous layer 64, but is not impregnated with a lubricant. Further, the second porous layer 65 has a larger proportion of voids (pore ratio or porosity) in the volume of the entire layer than the first porous layer 64.

The porosity of the porous layer can be changed by appropriately adjusting the cell diameter of the voids and / or the number of voids.

The resistance layer 66 is arranged outside the second porous layer 65 in the axial direction, and more specifically, the resistance layer 66 is provided at both ends in the axial direction of the roller portion 63A. The resistance layer 66 is a layer having a larger friction coefficient with the inner peripheral surface of the belt 62 than the first porous layer 64 impregnated with the lubricant. Further, the resistance layer 66 is configured so that the lubricant is less likely to be impregnated than the first porous layer 64.
The resistance layer 66 is, for example, a non-porous layer made of silicone rubber, has a large friction coefficient with the inner peripheral surface of the belt 62, and has oil repellency for sealing a lubricant.

Next, the operation of the fixing device 6 configured as described above will be described.
As shown in FIG. 2, when the heating roller 61 in contact with the outer peripheral surface of the belt 62 rotates, the belt 62 and the pressure roller 63 in contact with the inner peripheral surface of the belt 62 rotate with each other.
At this time, the pressure roller 63 rotates stably together with the belt 62 due to the frictional force between the resistance layers 66 provided at both ends in the axial direction and the inner peripheral surface of the belt 62. Further, the first porous layer 64 and the second porous layer 65 located on the radial outer side of the pressure roller 63 are crushed by the pressure from the belt 62 with the heating roller 61, so that the first porous layer 64 and the second porous layer 65 are first porous. The lubricant impregnated in the quality layer 64 is applied to the inner peripheral surface of the belt 62.
Therefore, while the belt 62 is stably rotated by the resistance layer 66, the lubricant can be stably applied to the inner peripheral surface of the belt 62 by the first porous layer 64.

Based on the above, the following effects can be obtained in the present embodiment.
A member for applying a lubricant to the inner peripheral surface of the belt 62 by providing the first porous layer 64 impregnated with the lubricant at a position where the pressure roller 63 comes into contact with the inner peripheral surface of the belt 62. Is not required to be provided separately from the pressure roller 63, so that the lubricant can be applied to the inner peripheral surface of the belt 62 without increasing the number of parts, and the belt guide 67, the pressure pad 69, and the belt 62 can be coated. The sliding resistance with the peripheral surface can be reduced.

The pressure roller 63 is provided with a resistance layer 66 having a larger friction coefficient with the inner peripheral surface of the belt 62 than the first porous layer 64 at a position where the pressure roller 63 comes into contact with the inner peripheral surface of the belt 62. Since the 63 rotates with the belt 62 and the belt 62 can be rotated stably, the lubricant is applied to the inner peripheral surface of the belt 62 as compared with the configuration in which the pressure roller 63 and the belt 62 slip and are difficult to rotate. It can be applied stably.

At least a part of the surface of the first porous layer 64 is located radially outside the pressure roller 63 with respect to the surface of the resistance layer 66 in a state where no pressure is applied between the pressure roller 63 and the heating roller 61. Therefore, when pressure is applied between the pressurizing roller 63 and the heating roller 61, the first porous layer 64 located on the outer side in the radial direction is crushed, and a lubricant is applied to the inner peripheral surface of the belt 62. Can be applied more reliably.

Since the resistance layer 66 is provided at both ends of the pressure roller 63 and the first porous layer 64 is provided between the resistance layers 66 provided at both ends of the pressure roller 63, the first porous layer 64 is provided. Compared with the configuration provided at the end of the pressure roller 63, the lubricant can be stably applied to the inner peripheral surface of the belt 62.

The first porous layer is provided between the first porous layer 64 and the resistance layer 66 by providing the second porous layer 65, which has a larger proportion of voids in the total volume of the layer than the first porous layer 64. It is possible to effectively absorb the lubricant flowing out from 64 in the axial direction.

Since the first porous layer 64 has a width W1 equal to or larger than the width W2 of the pressure pad 69 in the axial direction, the lubricant is applied from the first porous layer 64 to the pressure pad 69 via the inner peripheral surface of the belt 62. Can be supplied to the entire surface of the. As a result, the sliding resistance between the inner peripheral surface of the belt 62 and the pressure pad 69 can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. The specific configuration can be appropriately changed without departing from the spirit of the present invention.

In the above-described embodiment, the belt 62, the heating roller 61 as the opposing member, the pressure roller 63 as the rotating member, the belt guide 67 as the sliding contact member, and the pressure pad 69 are included, and the pressure roller 63. , The pressure belt type fixing device 6 in which the belt 62 is wound around the belt guide 67 and the pressure pad 69 is adopted, but the present invention is not limited to such a configuration.
For example, a heating belt wound around a heating roller may be adopted, and the opposing member may be a heating belt.
Further, a heat source, a first pressurizing roller, and a guide that is in sliding contact with the inner peripheral surface of the belt are arranged inside the endless belt, and a second pressurizing roller and a second pressurizing roller are located opposite each other across the belt. It is also possible to arrange a pressure roller. In this case, the first pressurizing roller corresponds to the rotating member, the second pressurizing roller corresponds to the opposing member, and the guide corresponds to the sliding contact member.

In the above-described embodiment, the first porous layer 64 and the resistance layer 66 having different thicknesses are provided on the outer peripheral surface of the roller portion 63A having a uniform thickness T0 in the axial direction, and the surface of the first porous layer 64 is provided. However, the present invention is not limited to such a configuration, although it is formed so as to be located radially outside the pressure roller 63 with respect to the surface of the resistance layer 66. For example, the roller portion 63A may have a crown shape in which the thickness of the central portion in the axial direction is thicker than the thickness of both ends in the axial direction, and the thickness of the first porous layer 64 and the resistance layer 66 may be the same.

In the above-described embodiment, the porosity of the second porous layer 65 is larger than the porosity of the first porous layer 64, but the present invention is not limited to such a configuration. For example, the porosity of the second porous layer 65 may be smaller than the porosity of the first porous layer 64. With such a configuration, it becomes difficult for the lubricant to flow out from the first porous layer 64 to the second porous layer 65.

In the above-described embodiment, the first porous layer 64, the second porous layer 65, and the resistance layer 66 are provided in contact with each other, but the present invention is not limited to such a configuration. For example, a gap may be provided between the second porous layer 65 and the resistance layer 66.

In the above-described embodiment, the resistance layer 66 is a non-porous layer, but the present invention is not limited to such a configuration. For example, the resistance layer may be formed from a rubber sponge having a closed cell structure.
Further, the resistance layer has a two-layer structure composed of an inner layer and an outer layer, an inner layer is formed by the same porous layer as the first porous layer 64, and the outer layer in contact with the inner peripheral surface of the belt 62 is coated with a silicone rubber. It may be formed. Further, the inner layer may have an oil-repellent coating layer for sealing the lubricant on the end face adjacent to the first porous layer 64.

Further, as shown in the following modification, the pressure roller 63 as a rotating member can be variously changed. In the following description, the same components as those in the above-described embodiment will be referred to by using the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 4A and 4B, in the pressure roller 163 according to the first modification, the first porous layer 164 and the two resistance layers 166 are in contact with the outer peripheral surface of the roller portion 63A, respectively. It is provided in a state of being.

The first porous layer 164 is provided between the resistance layers 166 provided at both ends of the pressure roller 163, and has a two-layer structure composed of an inner layer 164A and an outer layer 164B.
The inner layer 164A is a layer impregnated with a lubricant, and is composed of a heat-resistant resin appropriately selected from the same resin materials as the first porous layer 64 (see FIG. 3) of the above-described embodiment.

The outer layer 164B is a cylindrical porous layer provided on the outer peripheral surface of the inner layer 164A, and is composed of a heat-resistant resin appropriately selected from the same resin materials as the first porous layer 64 shown in FIG.
The outer layer 164B is a layer for adjusting and applying the amount of the lubricant supplied from the inner layer 164A to the inner peripheral surface of the belt 62. Therefore, the porosity of the outer layer 164B is smaller than the porosity of the inner layer 164A. For example, the outer layer 164B has a smaller cell diameter of voids and a smaller number of voids than the inner layer 164A.
Further, the thickness T3 of the outer layer 164B is thinner than the thickness T2 of the inner layer 164A.

The resistance layer 166 is made of the same material as the resistance layer 66 of the above-described embodiment.
Further, the thickness T6 of the resistance layer 166 is thicker than the thickness T2 of the inner layer 164A, and thinner than the sum of the thickness T2 of the inner layer 164A and the thickness T3 of the outer layer 164B.

According to the fixing device according to the first modification, the following effects can be obtained.

The first porous layer 164 has an inner layer 164A impregnated with a lubricant and an outer layer 164B having a smaller ratio of voids in the total volume of the layer than the inner layer 164A, so that the amount of lubricant supplied through the outer layer 164B can be adjusted. However, since the lubricant impregnated in the inner layer 164A can be applied, the lubricant can be stably applied to the inner peripheral surface of the belt 62.

Further, for example, even if the inner layer 164A is impregnated with more lubricant than the first porous layer 64 of the above-described embodiment, the supply amount of the lubricant can be adjusted by the outer layer 164B, so that the lubricant is the resistance layer 166. It is possible to suppress the flow to the surface.

It is also possible to combine the first modification with the above-described embodiment to provide the second porous layer 65 between the first porous layer 164 composed of the inner layer 164A and the outer layer 164B and the resistance layer 166.

In such a pressure roller, it is desirable to use silicone oil as a lubricant and to compose the first porous layer and the second porous layer with a material made of a fluororesin (PTFE, PFA, FEP, EEFT). ..

In such a configuration, by using a fluororesin having excellent wear resistance for the first porous layer and the second porous layer, the durability of the portion in sliding contact with the inner peripheral surface of the belt 62 is increased, and the first is By providing the two porous layers, it is possible to prevent the lubricant from adhering to the resistance layer made of silicone rubber.

As shown in FIGS. 5A and 5B, in the pressure roller 263 according to the second modification, the outer peripheral surface of the roller portion 63A is impregnated with the two first porous layers 64 and 3 The two resistance layers 66 are provided in contact with each other.
The resistance layer 66 is provided at the axial center portion and both end portions of the roller portion 63A, and two first porous layers 64 are provided between the three resistance layers 66, respectively.

According to the pressure roller 263 configured in this way, since the resistance layer 66 is provided at the axial center portion and both end portions of the roller portion 63A, the surface area in contact with the inner peripheral surface of the belt 62 becomes large, and the belt 62 Can be rotated more stably.

In the above-described embodiment and each modification, the first porous layer is provided on the outer peripheral surface of the roller portion 63A, but the present invention is not limited to such a configuration, and for example, the first one is provided on the outer peripheral surface of the rotating shaft 63B. A first porous portion having the same structure as the porous layer can be directly provided as a roller portion. Similarly, the second porous portion and the resistance portion having the same structure as the second porous layer and the resistance layer can be provided directly on the outer peripheral surface of the rotating shaft 63B.

In the above-described embodiment and each modification, it is desirable to appropriately determine the lubricant to be used according to the selection of the material of the sliding contact member in addition to the selection of the material constituting each member of the pressure roller.

In the above embodiment, the driving force is transmitted to the heating roller to rotate the driving force, and the belt and the pressure roller are rotated around. However, the present invention is not limited to such a configuration, and the driving force is applied to the pressure roller. It can also be configured to transmit and rotate the belt and heating rollers.

In the above-described embodiment and each modification, the resistance layers are provided at both ends of the pressure roller, but the first porous layer can also be provided at both ends.

In the above embodiment, the present invention is applied to a laser printer, but the present invention is not limited to such a configuration, and the present invention can also be applied to other image forming devices such as copiers and multifunction devices.

Further, each element described in the above-described embodiment and each modification can be arbitrarily combined and implemented.

6 Fixing device 61 Heating roller H Heat source 62 Belt 63 Pressurized roller 64 1st porous layer 65 2nd porous layer 66 Resistance layer 69 Pressurized pad W1 Width of 1st porous layer W2 Width of pressurized pad 163 Pressurized Roller 164 1st Porous Layer 164A Inner Layer 164B Outer Layer 166 Resistance Layer 263 Pressurized Roller

Claims (7)

With an endless belt,
An opposing member that comes into contact with the outer peripheral surface of the belt,
A rotating member that comes into contact with the inner peripheral surface of the belt and sandwiches the belt with the opposing member.
Including a sliding contact member that is in sliding contact with the inner peripheral surface of the belt.
The rotating member is provided with a first porous portion impregnated with a lubricant at a portion in contact with the inner peripheral surface of the belt, and is more than the first porous portion at a location in contact with the inner peripheral surface of the belt. A resistance portion having a large friction coefficient with the inner peripheral surface of the belt is provided.
At least a part of the surface of the first porous portion is located radially outside the rotating member with respect to the surface of the resistance portion.
The first porous portion has an inner layer impregnated with the lubricant and an outer layer in which the ratio of voids to the volume of the entire layer is smaller than that of the inner layer.
A fixing device characterized in that the thickness of the resistance portion is thicker than the thickness of the inner layer and thinner than the thickness of the inner layer and the outer layer added. The thickness of the resistive portion, the fixing device according to claim 1, characterized in that less than the thickness of the first porous portion. Claim 1 or claim, wherein the resistance portions are provided at both ends of the rotating member, and the first porous portion is provided between the resistance portions provided at both ends of the rotating member. Item 2. The fixing device according to item 2. Any one of claims 1 to 3 , wherein the first porous portion has an inner layer impregnated with the lubricant and an outer layer in which the ratio of voids to the volume of the entire layer is smaller than that of the inner layer. The fixing device according to one item. The fixing device according to any one of claims 1 to 4 , wherein the first porous portion has a width equal to or larger than that of the sliding contact member in the axial direction of the rotating member. The rotating member includes a rotating shaft and a roller portion that covers the outer periphery of the rotating shaft.
The fixing device according to any one of claims 1 to 5 , wherein the first porous portion is provided on an outer peripheral surface of the roller portion. The facing member is a heating roller in which a heat source is arranged.
The rotating member is a pressure roller that rotates with the belt sandwiched between the rotating member and the heating roller.
The fixing device according to any one of claims 1 to 6 , wherein the sliding contact member is a pressure pad that sandwiches the belt with the heating roller.

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