JP2020197670A - Fixing belt, fixing device, and image forming device - Google Patents

Abstract

To provide a highly reliable fixing belt which reduces slide resistance and has a long life and continues to offer stable sliding capability for a long time, and to provide a fixing device and an image forming device.SOLUTION: A fixing belt is provided, comprising a cylindrical base material 101a and a sliding layer 101b provided on an inner peripheral surface of the cylindrical base material 101a, the sliding layer 101b having solid lubricant particles unevenly distributed on a surface thereof.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fixing belt, a fixing device and an image forming device.

Conventionally, in the fixing process used for image forming devices such as copiers, printers, facsimiles, or multifunction devices thereof, cost reduction by energy saving and compactification has become the mainstream, and sliding fixing technology is often used. .. In the sliding fixing technique, the fixing belt is often slid mainly on the inner peripheral surface of the fixing belt and the nip forming portion paired with the inner peripheral surface of the fixing belt. Lubricants are mainly used for the sliding parts provided with the fixing belt and the nip forming part, and technological development is progressing on how to reduce the sliding resistance.

For example, in Patent Document 1, even when the fixing member is in sliding contact with the inner peripheral surface of the belt member, the lubricant interposed between the belt member and the fixing member is stably held over time. , A fixing device and an image forming device having high durability with less wear of the belt member and the fixing member have been proposed. Specifically, a lubricant is interposed between the fixing member and the belt member. The fixing member and the belt member each include a surface layer formed of a fluorine-containing material on the sliding contact surface where both members are in sliding contact, and one surface layer is formed in a porous shape, and at least one of them is formed. The surface energy of the surface layer of the lubricant is formed to be larger than the surface tension of the lubricant.

Japanese Unexamined Patent Publication No. 2010-026489

However, in the case of the fixing device of Patent Document 1, the lubricity of the sliding portion gradually increases due to the decrease of the lubricant that should be present in the sliding portion and the influence of the abrasion powder generated by the wear of the surface layer. It may decrease and the unit torque may increase over time. The increase in unit torque may cause slippage of the paper sent to the sliding part and damage to the fixing belt or pressure roller.

The present invention has been made to solve the above-mentioned problems, and provides a highly reliable fixing belt, fixing device and image forming device capable of reducing sliding resistance and continuing stable sliding with a long life. The purpose is to do.

In order to solve the above-mentioned problems, the fixing belt of the present invention includes a cylindrical base material and a sliding layer located on the inner peripheral surface of the cylindrical base material, and is solid on the surface of the sliding layer. It is characterized in that the lubricant particles are unevenly distributed.

According to the fixing belt of the present invention, a cylindrical base material and a sliding layer located on the inner peripheral surface of the cylindrical base material are provided, and solid lubricant particles are unevenly distributed on the surface of the sliding layer. As a result, the contact area between the fixing belt and the nip portion forming member can be reduced, and the solid lubricant particles and the nip portion forming member locally come into contact with each other, so that the sliding resistance can be reduced. It is possible to provide a highly reliable fixing device capable of continuing stable sliding with a long life.

It is a side sectional view which shows typically an example of the fixing device using the fixing belt of one Embodiment of this invention. It is a side sectional view which shows the outline of the fixing belt. It is a perspective view which shows the outline of the fixing belt axial end part of the fixing device. It is a side sectional view which shows the outline of the sliding layer of the fixing belt in 1st Embodiment of this invention. FIG. 5 is a side sectional view showing an outline of a sliding layer of a fixing belt according to a second embodiment of the present invention, which is different from FIG. It is a side sectional view which shows the outline of a pressure roller. It is a side sectional view which shows the outline of the nip part forming member. It is a side view which shows typically an example of the image forming apparatus using the fixing belt of one Embodiment of this invention. It is a side sectional view which shows the outline of the fixing belt of the comparative example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same components as those already described are designated by the same reference numerals and the description thereof will be omitted.

[Fixing device]
The fixing device 100 shown in FIG. 1 is a device that fixes toner as a coloring material on a recording medium such as paper. The fixing device 100 includes a fixing belt 101 according to an embodiment of the present invention, a pressure roller 102, a heating member 103, and a nip portion forming member 104.

<Fixing belt>
The fixing belt 101 includes a cylindrical base material 101a and a sliding layer 101b located on the inner peripheral surface of the cylindrical base material 101a (FIG. 2).

As the fixing belt 101, a thin-walled and flexible endless belt member is used. A cylindrical base material 101a formed of a metal material such as nickel or stainless steel or a resin material such as polyimide (PI) is provided on the inner peripheral side of the fixing belt 101 (FIG. 2).

Further, a release layer 101d formed of a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE) or the like can be provided on the outer peripheral side of the fixing belt 101 (FIG. 2).

An elastic layer 101c made of a rubber material such as silicone rubber, foamable silicone rubber, or fluororubber may be interposed between the cylindrical base material 101a and the release layer 101d (FIG. 2).

Further, the sliding layer 101b is provided on the inner peripheral side of the cylindrical base material 101a, that is, on the inner peripheral surface of the cylindrical base material 101a (FIG. 2). The sliding layer 101b has a high melting point and high temperature conditions such as a slidable material made of a fluororesin such as PFA or PTFE, or PI, polyamide-imide (PAI) or polyphenylene sulfide (PPS). Solid lubricant particles are dispersed and formed on a base 201 containing a material made of a usable binder resin or the like.

The fixing belt 101 may be thin and have a small diameter in order to reduce the heat capacity. Specifically, the thicknesses of the cylindrical base material 101a, the sliding layer 101b, the elastic layer 101c, and the release layer 101d constituting the fixing belt 101 are 20 to 50 μm, 5 to 20 μm, 50 to 300 μm, and 5, respectively. It can be set in the range of ~ 30 μm, and the total thickness of the fixing belt 101 can be set to 1 mm or less. In order to further reduce the heat capacity, the total thickness of the fixing belt 101 is preferably 0.2 mm or less, and more preferably 0.16 mm or less.

Further, the diameter of the fixing belt 101 can be set to 20 to 50 mm. In order to further reduce the heat capacity, it is desirable that the diameter of the fixing belt 101 is 30 mm or less.

FIG. 3 is a perspective view showing an outline of an axial end portion of the fixing belt 101 of the fixing device 100. In FIG. 3, only the configuration of one end of the fixing belt 101 is shown, but the opposite end of the fixing belt 101 has the same configuration. Hereinafter, the configuration of one end in the axial direction of the fixing belt 101 of the fixing device 100 will be described with reference to FIG.

As shown in FIG. 3, a flange 1001 which is a belt holding member can be inserted into the axial end portion of the fixing belt 101, and the axial end portion of the fixing belt 101 can be rotated by the flange 1001. Can be retained. The flange 1001 is composed of a locking guide portion and a rotation guide portion of the fixing belt 101.

As shown in FIG. 3, a slip ring 1002 as a protective member for protecting the end portion of the fixing belt 101 can be provided between the end surface of the fixing belt 101 and the facing surface of the flange 1001 facing the end surface. Since the retaining guide portion of the fixing belt 101 does not rotate, the retaining guide portion and the fixing belt 101 may be worn due to contact between the retaining guide portion and the end portion of the fixing belt 101 or rotation of the fixing belt 101. is there. Therefore, in order to prevent such wear, a slip ring 1002 that can rotate with the rotation of the fixing belt 101 can be provided between the fixing belt 101 and the anti-slip guide portion. The slip ring 1002 can prevent the end of the fixing belt 101 from directly hitting the anti-slip guide portion when the fixing belt 101 is displaced in the axial direction, and the end of the fixing belt 101 or the flange 1001 can be prevented. Can be prevented from being worn or damaged. Further, the slip ring 1002 can be fitted with a margin to the outer peripheral surface of the flange 1001. As a result, when the end of the fixing belt 101 comes into contact with the slip ring 1002, the slip ring 1002 may rotate with the fixing belt 101, or the slip ring 1002 may stop without rotating. Absent. Further, the flange 1001 may be fixed to the side plate of the fixing device 100.

The material of the slip ring 1002 is not particularly limited, but for example, a super engineering plastic having heat resistance can be used. Specifically, it is preferable to use PPS, polyetheretherketone (PEEK), PAI, PTFE and the like.

In the present embodiment, the members that come into contact with the inner peripheral surface of the fixing belt 101 may be only the flange 1001 and the nip portion forming member 104. In addition to these parts, there may be no member that comes into contact with the inner peripheral surface of the fixing belt 101 to guide the rotation of the fixing belt 101.

[Sliding layer]
<First Embodiment>
As the first embodiment of the sliding layer 101b, FIG. 4 shows the sliding layer 200. The solid lubricant particles 202 are unevenly distributed on the surface 200a of the sliding layer 200, and the solid lubricant particles 202 are not uniformly dispersed on the surface 200a.

<Second Embodiment>
As the first embodiment of the sliding layer 101b, the sliding layer 300 is shown in FIG. The first solid lubricant particles 301 and the second solid lubricant particles 302 are unevenly distributed on the surface 300a of the sliding layer 300 as solid lubricant particles, and the first solid lubricant particles 301 and the second solid lubricant particles 301 and the second solid lubricant particles 302 are unevenly distributed on the surface 300a. The solid lubricant particles 302 are not in a uniformly dispersed state.

Further, as in the second embodiment, it is preferable that the first solid lubricant particles 301 that are densely distributed due to uneven distribution are larger than the second solid lubricant particles 302 that are scattered due to uneven distribution. As a result, the sliding resistance can be further reduced, and a more reliable fixing belt capable of continuing stable sliding with a long life can be obtained.

The ratio of the area where the solid lubricant particles 202 are unevenly distributed to the area of the surface 200a of the sliding layer 200 is preferably 1 to 30%. Similarly, the ratio of the area where the solid lubricant particles 301 and 302 are unevenly distributed to the area of the surface 300a of the sliding layer 300 is preferably 1 to 30%. When this ratio is 1 to 30%, it is possible to obtain a highly reliable fixing belt that can reduce sliding resistance and can continue stable sliding with a long life. When this ratio is less than 1%, in addition to the contact between the solid lubricant particles and the nip portion forming member 104, the area of direct contact between the base 201 of the sliding layer 101b and the nip portion forming member 104 becomes large. , The effect of reducing sliding resistance may not be sufficiently obtained. Further, when this ratio is higher than 30%, the local contact between the solid lubricant particles and the nip portion forming member is not local, and the effect of reducing the sliding resistance may be insufficient. ..

The sliding layer 200 or 300 may contain a cured product of a thermosetting resin. The thermosetting resin is not particularly limited, and examples thereof include phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane resin, and thermosetting polyimide. By including any of these, the heat resistance of the sliding layers 200 and 300 can be improved. In particular, the heat resistance can be further improved by containing a polyimide or a polyamide-imide resin as the thermosetting resin having heat resistance. The cured product of the thermosetting resin may be contained, for example, so as to be dispersed in the base 201, or may be contained in a state of being compatible with the thermoplastic resin contained in the base 201. Further, the base 201 may be formed of the thermoplastic resin.

Further, in the sliding layer 200 or 300, the solid lubricant particles 202, 301 or 302 may be one or more selected from graphite, fluororesin and molybdenum disulfide. With these materials, solid and lubricious particles can be easily formed.

The solid lubricant particles 202, 301 or 302 may be unevenly distributed as secondary particles composed of aggregates of primary particles. Since it is a secondary particle, the solid lubricant particles are likely to be unevenly distributed on the surface of the sliding layer. As a result, the sliding resistance of the fixing belt 101 can be reduced, and a highly reliable fixing belt 101 capable of continuing stable sliding with a long life can be obtained. For example, the secondary particles 202b in which the primary particles 202a of the solid lubricant particles 202 are aggregated (FIG. 4) and the primary particles 301a of the first solid lubricant particles 301 are aggregated and raised in a mountain shape to form an aggregate. Secondary particles 301b (FIG. 5) can be mentioned.

<Pressurized roller>
The pressurizing roller 102 is a roller that pressurizes the outer peripheral surface 101x of the fixing belt 101. Examples of the pressurizing roller 102 include a pressurizing member made of an opposed rotating body rotatably provided so as to face the fixing belt 101.

Specifically, as shown in FIG. 6, it can be composed of a core metal 102a, an elastic layer 102b, and a release layer 102c. The elastic layer 102b is arranged on the surface of the core metal 102a, and can be made of foamable silicone rubber, silicone rubber, fluororubber, or the like. Further, the release layer 102c is provided on the surface of the elastic layer 102b and can be made of PFA, PTFE or the like.

The pressurizing roller 102 is in contact with the nip portion forming member 104 via the fixing belt 101 by being pressed toward the fixing belt 101 side by the pressing means. At the position where the pressure roller 102 and the fixing belt 101 are in pressure contact with each other, the elastic layer 102b of the pressure roller 102 is crushed to form a nip portion 1N having a predetermined width. The pressurizing roller 102 is rotationally driven by a drive source such as a motor provided in the image forming apparatus. When the pressurizing roller 102 is rotationally driven, the driving force is transmitted to the fixing belt 101 by the nip portion 1N so that the fixing belt 101 can be driven in a secondary rotation. Further, the rotary drive source is on the fixing belt 101 side, and the drive force transmitted from the nip portion 1N is transmitted to the pressurizing roller 102, so that the pressurizing roller 102 can be driven in a slave rotation.

In the present embodiment, the pressure roller 102 is a solid roller, but it may be a hollow roller. In that case, a heating source such as a halogen heater may be arranged inside the pressurizing roller 102.

It is also possible to take a mode in which the pressure roller 102 does not have the elastic layer 102b. In this case, the heat capacity is reduced and the fixing property is improved, but when the unfixed toner is crushed and fixed by the nip portion 1N, minute irregularities on the surface of the fixing belt 101 are transferred to the image, and the image There is a possibility that uneven gloss may occur in the solid part. In order to prevent this, it is desirable to provide an elastic layer 102b having a thickness of 100 μm or more. By providing the elastic layer 102b having a thickness of 100 μm or more, it is possible to absorb minute irregularities due to elastic deformation of the elastic layer 102b. As a result, it becomes possible to prevent the occurrence of uneven gloss.

The elastic layer 102b may be solid rubber, but if there is no heating source inside the pressure roller 102, foamable sponge rubber may be used. Sponge rubber is preferable because it has higher heat insulating properties and is less likely to be deprived of heat from the fixing belt 101 through the nip portion 1N. Further, the pressurizing roller 102 and the fixing belt 101 are not limited to the case where they are in pressure contact with each other, and the pressurizing roller 102 and the fixing belt 101 may be configured to simply contact each other without applying pressure.

In this embodiment, the diameter of the pressure roller 102 can be set to 20 to 50 mm. For example, the diameter of the fixing belt 101 and the diameter of the pressure roller 102 are often set to be equal. However, the configuration is not limited to this, and for example, the diameter of the fixing belt 101 may be smaller than the diameter of the pressure roller 102. In this case, the curvature of the fixing belt 101 at the nip portion 1N is smaller than the curvature of the pressure roller 102. Therefore, the recording medium 107 discharged from the nip portion 1N is easily separated from the fixing belt 101.

<Heating member>
The heating member 103 is a member that heats the fixing belt 101. For example, as a heat source for heating the fixing belt 101, a heating member 103 arranged inside the fixing belt 101 can be mentioned (FIG. 1).

Examples of the heating member 103 include a halogen heater, and both ends of the halogen heater can be fixed to the side plates of the fixing device 100. The halogen heater generates heat by controlling the output from, for example, a power supply unit arranged in the image forming apparatus. The output control of the halogen heater can be performed based on the detection result of the surface temperature of the fixing belt 101 by the temperature sensor. By controlling the output of the halogen heater in this way, the temperature of the fixing belt 101 (fixing temperature) can be maintained at a desired temperature.

Further, as the heating member 103 for heating the fixing belt 101, an IH (electromagnetic induction heating), a resistance heating element, a carbon heater or the like may be used in addition to the halogen heater.

The fixing device 100 of the present embodiment has been devised in various configurations in order to further improve performance such as energy saving and shortening of the first print time as compared with the conventional fixing device. Specifically, the heating member 103 allows the fixing belt 101 to be directly heated at a portion other than the nip portion 1N (direct heating method). Further, the fixing belt 101 can be configured so that nothing is interposed with the heating member 103. With this configuration, at the position where the heating member 103 and the fixing belt 101 face each other, the radiant heat generated from the heating member 103 is directly applied to the fixing belt 101.

<Nip part forming member>
The nip portion forming member 104 is fixed so as to be in sliding contact with the inner peripheral surface of the fixing belt 101, and is pressed against the pressure roller 102 via the fixing belt 101 to form the nip portion 1N to which the recording medium 107 is conveyed. (Fig. 1).

The nip portion forming member 104 includes, for example, a base pad 104a as shown in FIG. 7 and a low friction sliding member 104b that rubs against the inner peripheral surface of the fixing belt 101 provided on the surface of the base pad 104a. Can be done. The base pad 104a is a member that receives the pressing force of the pressurizing roller 102 to determine the shape of the nip portion 1N. Therefore, the base pad 104a may be arranged in parallel with the axial direction of the fixing belt 101 or the axial direction of the pressure roller 102.

Further, the base pad 104a may be made of a heat-resistant member having a heat-resistant temperature of 200 ° C. or higher. As a result, it is possible to prevent deformation of the base pad 104a due to heat in the toner fixing temperature range and secure a stable state of the nip portion 1N. As a result, a stable image can be obtained.

The base pad 104a has a function of determining the shape of the nip portion 1N composed of the pressure roller 102 facing the sliding member 104b. Therefore, the surface facing the nip portion 1N is substantially flat, and a material having a certain degree of rigidity can be used as the material for maintaining this shape.

For example, a general heat-resistant resin material can be used. Specifically, PPS, PAI, polyethersulfone (PES), liquid crystal polymer (LCP), polyethernitrile (PEN), polyetheretherketone (PEEK) and the like can be used.

Further, a sliding member 104b having a low friction coefficient may be arranged on the surface of the base pad 104a at least on the inner peripheral surface side of the fixing belt 101 (FIG. 7). The sliding member 104b can slide the surface of the fixing belt 101 when the fixing belt 101 rotates. The sliding member 104b is used to reduce the driving torque generated in the sliding fixing belt 101 and to reduce the load due to the frictional force on the fixing belt 101.

Further, the sliding member 104b is impregnated with a lubricant. Examples of the lubricant include silicone oil, which is desirable in terms of excellent heat resistance, durability, and lubricating ability, and is desirable because a lubricant having various viscosities can be selected depending on the conditions of use.

Fluorine grease and silicon-based grease can be used as other lubricants. The lubricant is not limited to impregnating the entire sliding member 104b with one type, but it is also possible to use a plurality of types of lubricants having different viscosities and materials at the central portion and both end portions in the axial direction.

(Other configurations)
The fixing device 100 according to the embodiment of the present invention may include other configurations in addition to the above-mentioned fixing belt and the like. For example, a nip portion forming member stay 106 as a support member for supporting the nip portion forming member 104 can be provided inside the fixing belt 101 (FIG. 1).

By fixing and supporting the nip portion forming member 104 with the nip portion forming member stay 106, bending of the nip portion forming member 104 due to the pressure of the pressure roller 102 is suppressed, and the nip portion forming member 104 is parallel to the axial direction of the pressure roller 102. Therefore, a uniform nip width can be obtained.

The nip portion forming member stay 106 is preferably formed of a metal material having high mechanical strength such as stainless steel or iron in order to satisfy the bending prevention function of the nip portion forming member 104, but a resin material can also be used. Is.

Further, a temperature sensor as a temperature detecting means for detecting the temperature of the fixing belt 101, a separating member as a recording medium separating means for separating the recording medium 107 from the fixing belt 101, and a pressurizing roller 102 for pressurizing the fixing belt 101. A pressure means can be provided.

Hereinafter, an example of the basic operation of the fixing device 100 of the present embodiment will be described with reference to FIG.

First, when the power of the image forming apparatus including the fixing device 100 is turned on, electric power is supplied to the heating member 103, and the pressurizing roller 102 starts rotational driving in the direction of 1A shown in FIG. As a result, the fixing belt 101 is driven to rotate in the direction of 1B shown in FIG. 1 due to the frictional force with the pressure roller 102. After that, the recording medium 107 on which the unfixed toner image 108 is mounted by the image forming step is conveyed in the direction of 1C while being guided by the guide plate, and the nip portion of the fixing belt 101 and the pressure roller 102 in the pressure contact state. It is sent to 1N. Then, the recording medium 107 is heated by the heating member 103, and the toner image 108 is fixed on the surface of the recording medium 107 by the heat generated by the fixing belt 101 and the pressing force between the fixing belt 101 and the pressure roller 102. Toner. The recording medium 107 on which the toner image 108 is fixed is carried out from the nip portion 1N to the opposite side. At this time, the recording medium 107 is separated from the fixing belt 101 in such a manner that the tip of the recording medium 107 comes into contact with the tip of the separating member to guide the recording medium 107 in the direction of pulling it apart. After that, the separated recording medium 107 is carried out of the fixing device 100 and stocked in the paper output tray.

[Image forming device]
An image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. The image forming apparatus 500 of the present embodiment utilizes an electrophotographic method, and can include the fixing apparatus 100 described above.

FIG. 8 is a schematic configuration diagram showing an example of the entire image forming apparatus including the fixing roller according to the embodiment of the present invention. In the present embodiment, the image forming apparatus 500 includes an image forming unit for a tandem color printer. However, the image forming apparatus of the present invention is not limited to this, and may be a rotary color printer or a monochrome printer. Further, the image forming apparatus is not limited to a printer, and may be various image forming apparatus such as a copying machine, a facsimile, or a combination machine thereof.

Four toner bottles 602Y, 602M, 602C, and 602K corresponding to each color (yellow, magenta, cyan, and black) are detachably (replaceable) in the bottle accommodating portion 601 installed above the main body of the image forming apparatus 500. is set up. An intermediate transfer unit 85 is arranged below the bottle accommodating portion 601. Image-forming units 4Y, 4M, 4C, and 4K corresponding to each color (yellow, magenta, cyan, and black) are arranged side by side so as to face the intermediate transfer belt 78 installed in the intermediate transfer unit 85. Photoreceptor drums 5Y, 5M, 5C, and 5K are arranged in the image forming portions 4Y, 4M, 4C, and 4K, respectively. In addition, a charging unit 75, a developing device 76, a cleaning unit 77, a static elimination unit, and the like are arranged around the photoconductor drums 5Y, 5M, 5C, and 5K, respectively. Then, each of the photoconductor drums 5Y, 5M, 5C, and 5K is rotated, and the following image forming process is performed on each of the photoconductor drums 5Y, 5M, 5C, and 5K, and each photoconductor drum is subjected to the following image formation process. Images of each color are formed on 5Y, 5M, 5C, and 5K. Here, the image forming process refers to a charging process, an exposure process, a developing process, a transfer process, and a cleaning process.

The image forming process for the photoconductor drums 5Y, 5M, 5C, and 5K will be described below. The photoconductor drums 5Y, 5M, 5C, and 5K are rotationally driven clockwise in FIG. 8 by a drive motor. Then, in the charging unit 75 (only those corresponding to the photoconductor drum 5K are shown in FIG. 8), the surfaces of the photoconductor drums 5Y, 5M, 5C, and 5K are uniformly charged (charging step). After being charged, the surfaces of the photoconductor drums 5Y, 5M, 5C, and 5K are irradiated and exposed by the laser beam emitted from the exposed unit 40, and an electrostatic latent image corresponding to each color is formed (exposure step). The photoconductor drums 5Y, 5M, 5C, and 5K on which the latent image was formed have an electrostatic latent image formed by the developing device 76 (in FIG. 8, only those corresponding to the photoconductor drum 5K are coded). Toner development is performed to form a toner image of each color (development process).

Further, the toner image on the photoconductor drums 5Y, 5M, 5C, and 5K is transferred onto the intermediate transfer belt 78 by the intermediate transfer belt 78 and the primary transfer bias rollers 79Y, 79M, 79C, 79K (primary transfer). Process). By superimposing the toner image on the intermediate transfer belt 78 in this way and transferring the toner image, a color image is formed on the intermediate transfer belt 78.

After the transfer, the photoconductor drums 5Y, 5M, 5C, and 5K reach the cleaning unit 77, and the untransferred toner remaining on the surface of the photoconductor drums 5Y, 5M, 5C, and 5K is removed by the cleaning blade of the cleaning unit 77. It is collected mechanically (cleaning process). In FIG. 8, only those corresponding to the photoconductor drum 5K are designated by reference numerals. After that, the residual potential on the surface of the photoconductor drums 5Y, 5M, 5C, and 5K is removed by the static elimination unit. In this way, a series of image forming processes for the photoconductor drums 5Y, 5M, 5C, and 5K are completed.

Next, a series of transfer processes performed on the intermediate transfer belt 78 will be described.

The intermediate transfer unit 85 includes an endless intermediate transfer belt 78, four primary transfer bias rollers 79Y, 79M, 79C, 79K, a secondary transfer backup roller 82, a cleaning backup roller 83, and a tension roller 84. It is composed of an intermediate transfer cleaning unit 80 and the like.

The intermediate transfer belt 78 is stretched and supported by the secondary transfer backup roller 82, the cleaning backup roller 83, and the tension roller 84, and is moved in the direction of the arrow in FIG. 8 by the rotational drive of the secondary transfer backup roller 82. The primary transfer bias rollers 79Y, 79M, 79C, and 79K form the primary transfer nip so that the intermediate transfer belt 78 is sandwiched between the photoconductor drums 5Y, 5M, 5C, and 5K, respectively. A transfer bias opposite to the polarity of the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, and 79K. The intermediate transfer belt 78 travels in the direction of the arrow and sequentially passes through the primary transfer nip between the intermediate transfer belt 78 and the photoconductor drums 5Y, 5M, 5C, and 5K. In this way, the toner images of each color on the photoconductor drums 5Y, 5M, 5C, and 5K are superimposed on the intermediate transfer belt 78, and the primary transfer is performed.

After the primary transfer, the intermediate transfer belt 78 reaches a position facing the secondary transfer roller 89. At this position, the secondary transfer backup roller 82 forms the secondary transfer nip so as to sandwich the intermediate transfer belt 78 with the secondary transfer roller 89. In the secondary transfer nip, the four-color toner images formed on the intermediate transfer belt 78 are transferred onto the conveyed recording medium P. After the transfer, the intermediate transfer belt 78 reaches the intermediate transfer cleaning unit 80, and the untransferred toner on the intermediate transfer belt 78 is collected. In this way, a series of transfer processes performed on the intermediate transfer belt 78 is completed.

Here, the recording medium 107 conveyed to the position of the secondary transfer nip is conveyed from the paper feeding unit 50 arranged below the main body of the image forming apparatus 500 via the paper feeding roller 97 and the resist roller 98. It is a thing. That is, a plurality of recording media 107 such as transfer papers are stacked and stored in the paper feed unit 50. Then, when the paper feed roller 97 is rotationally driven in the counterclockwise direction in FIG. 8, the paper feed roller 97 is fed to the resist roller 98 in order from the highest recording medium 107. The recording medium 107 conveyed to the resist roller 98 temporarily stops at the position of the roller nip of the resist roller 98 whose rotational drive has stopped. Then, the resist roller 98 is rotationally driven in time with the toner image on the intermediate transfer belt 78, so that the recording medium 107 is conveyed toward the secondary transfer nip. In this way, the toner image is transferred onto the recording medium 107.

The recording medium 107 on which the color image is transferred by the secondary transfer nip is conveyed to the fixing device 100. Then, the recording medium 107 is heated and pressed by the fixing belt 101 and the pressure roller 102 in the fixing device 100, and the toner image transferred to the surface is fixed on the recording medium 107. After that, the recording medium 107 is discharged to the outside of the main body of the image forming apparatus 500 via the paper ejection roller 99, and is sequentially stacked on the stack portion 60.

As described above, the image formation on the recording medium 107 by the image forming apparatus 500 is completed.

In addition, the best configuration, method, and the like for carrying out the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention is particularly illustrated and described primarily with respect to a particular embodiment, it does not deviate from the scope of the technical idea and purpose of the present invention and has a shape relative to the embodiments described above. , Materials, quantities, and other detailed configurations can be modified by those skilled in the art.

Therefore, the description limiting the shapes, materials, etc. disclosed above is merely an example for facilitating the understanding of the present invention, and does not limit the present invention. Therefore, those shapes, materials, etc. The description by the name of the member which removes a part or all of the limitation such as is included in the present invention.

Hereinafter, examples of the present invention will be described. In the examples, an experiment was conducted using the fixing device 100 shown in FIG.

[Example 1]
<Fixing belt 101>
The fixing belt 101 used had a four-layer structure consisting of a cylindrical base material 101a, a sliding layer 101b, an elastic layer 101c, and a release layer 101d (FIG. 2).

(Formation of Cylindrical Base Material 101a)
The cylindrical base material 101a has a metal composition of nickel (Ni) and copper (Cu) as a material, the film thickness of the Ni layer is 30 μm, the film thickness of the Cu layer is 10 μm, and Ni is Ni with the Ni layer inside. A Cu layer having a thickness of 40 μm was used by laminating the Cu layer on the outer peripheral side of the layer. Although not used in this embodiment, it is also possible to use a cylindrical base material having a three-layer structure in which a Ni layer is further provided on the outer peripheral side of the Cu layer. Oxidation of the Cu layer can be prevented by providing the Ni layer as the outermost layer of the cylindrical base material.

The cylindrical base material 101a was formed by an electroforming method. Specifically, first, Ni is electrodeposited on the matrix to form a Ni layer, and then Cu is further electrodeposited on the Ni layer to form a Cu layer, thereby forming a cylindrical group. The material 101a was formed.

Graphite powder (graphite powder J-CPB manufactured by Nippon Graphite Co., Ltd.) as solid lubricant particles in 49.4 parts of NMP (N-methylpyrrolidone) compared to 47.6 parts of polyimide varnish (U-wanis A manufactured by Ube Kosan Co., Ltd.) ) 52.4 parts of NMP-graphite dispersion liquid in which 3 parts were dispersed was added and mixed and stirred to prepare a paint for forming the sliding layer 200. The prepared paint was allowed to stand for 24 hours or more to settle the solid lubricant particles. Then, the paint on which the solid lubricant particles are precipitated is transferred to a rotatable container and rotated and stirred, and the paint after the rotary stirring is spray-coated on the inner peripheral surface of the cylindrical base material 101a and dried. A sliding layer 200 having a film thickness of 15 μm was formed. The formation of the sliding layer is not limited to spray coating, but dipping coating is also possible, and heat treatment can be performed by a firing step instead of drying the coating film. Further, as the coating material for forming a sliding layer, a mixed material in which PTFE powder or a PTFE dispersion liquid in which PTFE is dispersed in water or a solvent is added to a PAI resin coating material and mixed by stirring can also be used.

FIG. 4 shows a side sectional view showing an outline of the sliding layer 200 of the first embodiment. The dried product of the polyimide varnish is the base 201, and the graphite is the solid lubricant particles 202. When the uneven distribution state of the solid lubricant particles 202 was confirmed based on (measurement of the uneven distribution ratio) described later, as shown in FIG. 4, the solid lubricant particles 202 were unevenly distributed on the base 201 without being uniformly dispersed. ..

(Formation of elastic layer 101c)
Silicone rubber (Asahi Kasei Wacker Silicone Co., Ltd. 3390/30) was dip-coated on the outer surface of the cylindrical base material 101a to form an elastic layer 101c having a film thickness of 120 μm. It is possible to adopt a coating method such as die coating instead of dipping coating, and the silicone rubber is filled with a filler for imparting heat resistance or a filler for enhancing thermal conductivity. It is possible.

(Formation of release layer 101d)
The surface of the elastic layer 101c was spray-coated with a dispersion in which PFA was dispersed in water to form a paint to form a release layer 101d having a film thickness of 7 μm. It is possible to adopt dipping coating instead of spray coating. Due to the formation of the release layer 101d, the outer diameter of the fixing belt 101 became 30 mm.

<Pressurized roller 102>
A pressure roller 102 was provided in an arrangement facing the fixing belt 101. As the pressurizing roller 102, a core metal 102a, an elastic layer 102b, and a release layer 102c were used (FIG. 6). The core metal 102a was made of an iron-based material and was a rigid body having high rigidity. The core metal 102a may be solid, but in Example 1, a hollow core metal 102a having an outer diameter of 10 mm and a thickness of 1.5 mm was used. An elastic layer 102b is provided on the surface side of the core metal 102a. Silicone rubber is used as the material of the elastic layer 102b, and a material composed of a foam silicone rubber is used. The elastic layer 102b made of the foam silicone rubber is formed on the surface side of the core metal 102a by, for example, a casting method or the like. Further, a conductive tube in which carbon black is mixed with PFA is provided on the elastic layer 102b as a release layer 102c, and layers are adhered between the elastic layer 102b and the release layer 102c. The one provided with the primer layer, which is the role of causing the release, was used. The release layer 102c was covered with a PFA tube.

<Nip portion forming member 104>
As the nip portion forming member 104, a member composed of a base pad 104a and a sliding member 104b was used (FIG. 7). The sliding member 104b was impregnated with silicone oil having a viscosity of 300 mPas as a lubricant.

(Measurement of uneven distribution ratio)
After performing energy dispersive X-ray analysis (EDS) on the surface of the sliding layer and performing element mapping, the ratio of the secondary particle aggregate portion of the solid lubricant particles is calculated from the area of the mapping data image, and this is calculated as a solid. The uneven distribution ratio of the lubricant particles was used.

(Particle diameter of solid lubricant particles)
The primary particle size and the secondary particle size of the solid lubricant were measured using a particle size distribution measuring device. As the particle size distribution measuring instrument, Microtrack MT3000II manufactured by Microtrack Bell Co., Ltd. was used.

(Measurement of dynamic torque)
The dynamic torque was evaluated using a stand-alone tester. The running test conditions were short-term intermittent running at a temperature of 165 ° C., a linear speed of 256 mm / s, a drive of 8.2 s / a stop of 1.8 s. In the test, the unit tester was continuously driven without passing paper, and the torque during driving was read from the torque meter connected to the drive motor. In the running test, the dynamic torque of the motor that rotationally drives the unit tester was measured when the number of sheets to be passed was 650,000.

[Example 2]
Unlike the sliding layer 200 of the first embodiment, the conditions were the same as those of the first embodiment except that the sliding layer 300 was shown in FIG. That is, using three parts of the same solid lubricant particles as in Example 1, unlike Example 1, the paint was allowed to stand for 24 hours in a state of being heated to 40 ° C. without dispersing the solid lubricant particles. It was. Then, the sliding layer 300 was formed by painting.

FIG. 5 shows a side sectional view showing an outline of the sliding layer 300 of the second embodiment. The first solid lubricant particles 301 and the second solid lubricant particles 302 were unevenly distributed on the sliding layer 300. The particle size of the first solid lubricant particles 301 and the particle size of the second solid lubricant particles 302 were different, and the particle size of the first solid lubricant particles 301 was larger than that of the second solid lubricant particles 302. The first solid lubricant particles 301 exist as secondary particles 301b, which are aggregates in which the primary particles 301a are densely packed with each other, and the secondary particles 301b have a shape protruding from the surface of the sliding layer 300. The secondary particles 301b were unevenly distributed on the surface of the sliding layer 300.

[Example 3]
The conditions were the same as in Example 2 except that the uneven distribution ratio was different from that of the sliding layer 300 of Example 2. Specifically, the sliding layer 300 was formed in the same manner as in Example 2 except that the mass ratio of the solid lubricant particles was increased from 3 parts to 10 parts in Example 2 to form a paint.

[Comparison example]
As shown in FIG. 9, the conditions were the same as in Example 1 except that the sliding layer 400 in which the solid lubricant particles 401 were uniformly dispersed was formed on the cylindrical base material 101a. Specifically, using the same solid lubricant particles as in Example 1, a paint for the sliding layer was prepared as in Example 1, and the ultrasonic disperser was installed without standing and rotating and stirring. It was ultrasonically dispersed for 30 minutes with respect to a liquid volume of 500 ml of the paint. The ultrasonic dispersion reduces the average particle size of the solid lubricant particles, weakens the bonds between the particles, and allows the solid lubricant particles to be uniformly present on the film. Then, the sliding layer 400 was formed by spray coating under the same conditions as in Example 1.

Table 1 shows the measurement results of the dynamic torque carried out in Examples 1 to 3 and Comparative Examples, the presence or absence of uneven distribution of solid lubricant particles, the ratio of uneven distribution, and the particle diameters of the first solid lubricant particles and the second solid lubricant particles. , Indicates the judgment result. The judgment was 0 when the dynamic torque was less than 0.7 Nm, and x when the dynamic torque was 0.7 Nm or more. Further, in Table 1, the average particle size of the first solid lubricant particles is shown as the C1 particle size, and the average particle size of the second solid lubricant particles is shown as the C2 particle size. Since there is no distinction between the first solid lubricant particles and the second solid lubricant particles in Example 1 and Comparative Example, Table 1 shows the average particle size of the solid lubricant particles.

From the results in Table 1, the dynamic torque could be reduced by unevenly distributing the solid lubricant particles on the surface of the sliding layer (Examples 1 to 3). In particular, two types of solid lubricant particles of different sizes are used to form protruding secondary particles composed of aggregates of primary particles of larger solid lubricant particles (first solid lubricant particles). By unevenly distributing the secondary particles, the dynamic torque could be further reduced (Examples 2 and 3). Further, by increasing the uneven distribution ratio, the dynamic torque could be further reduced (Example 3).

4Y, 4M, 4C, 4K Image-forming unit 5Y, 5M, 5C, 5K Photoreceptor drum 40 Exposure unit 50 Paper feed unit 75 Charging unit 76 Developer 77 Cleaning unit 78 Intermediate transfer belt 79Y, 79M, 79C, 79K Primary transfer Bias roller 80 Intermediate transfer cleaning unit 82 Secondary transfer backup roller 83 Cleaning backup roller 84 Tension roller 85 Intermediate transfer unit 97 Paper feed roller 98 Resist roller 100 Fixing device 101 Fixing belt 101a Cylindrical base material 101b Sliding layer 101c Elastic layer 101d Release layer 101 x Outer peripheral surface 102 Pressurized roller 102a Core metal 102b Elastic layer 102c Release layer 103 Heating member 104 Nip part forming member 104a Base pad 104b Sliding member 106 Nip part forming member Stay 107 Recording medium 108 Toner image 200 Sliding Layer 200a Surface 201 Base 202 Solid Lubricants Particles 202a Primary Particles 202b Secondary Particles 300 Sliding Layer 300a Surface 301 First Solid Lubricants Particles 301a Primary Particles 301b Secondary Particles 302 Second Solid Lubricants Particles 400 Sliding Layer 401 Solid Lubricant Particle 500 Image Forming Device 601 Bottle Storage 602Y, 602M, 602C, 602K Toner Bottle 1001 Flange 1002 Slip Ring 1A Direction 1B Direction 1C Direction 1N Nip Part

Claims (7)

Cylindrical base material and
A sliding layer located on the inner peripheral surface of the cylindrical base material is provided.
A fixing belt in which solid lubricant particles are unevenly distributed on the surface of the sliding layer. The fixing belt according to claim 1, wherein the solid lubricant particles are larger in the first solid lubricant particles that are densely distributed due to uneven distribution than in the second solid lubricant particles that are scattered due to uneven distribution. The fixing belt according to claim 1 or 2, wherein the ratio of the area where the solid lubricant particles are unevenly distributed to the surface area of the sliding layer is 1 to 30%. The one according to any one of claims 1 to 3, wherein the sliding layer contains a cured product of a thermosetting resin, and the solid lubricant particles are one or more selected from graphite, fluororesin, and molybdenum disulfide. Fixing belt. The fixing belt according to any one of claims 1 to 4, wherein the solid lubricant particles are unevenly distributed as secondary particles composed of aggregates of primary particles. A fixing device that fixes toner on a recording medium.
The fixing belt according to any one of claims 1 to 5 and
A pressure roller that pressurizes the outer peripheral surface of the fixing belt, and
A nip portion forming member which is fixed so as to be slidably contacted with the inner peripheral surface of the fixing belt and is pressed against the pressure roller via the fixing belt to form a nip portion to which the recording medium is conveyed.
A heating member that heats the fixing belt and
A fixing device equipped with. An image forming apparatus comprising the fixing belt according to any one of claims 1 to 5.

Images