JP2006039161A - Endless belt and heat fixing device - Google Patents

Abstract

In a fixing device using a belt having a metal base layer, high-frequency sound caused by stick-slip is reduced.
A multi-layered endless belt comprising a metal base layer and a resin layer has a heat-resistant and wear-resistant resin layer in which molybdenum disulfide is blended in a polyamide-imide resin in an amount of 20 wt% or more and less than 30 wt% on the innermost surface. It is characterized by. The heat-resistant and wear-resistant sliding layer has a surface roughness (Rz) of 0.3 μm or more and 5.0 μm or less. Further, the heat-resistant and wear-resistant resin layer is formed with a thickness of 1 μm or more and 20 μm or less.
[Selection] Figure 2

Description

  The present invention relates to an endless belt and a heat fixing device used in a heat fixing device of a toner image forming apparatus such as a copying machine, a printer, and a facsimile machine.

  In general, in a heat fixing device used in an electrophotographic system, a rotating body such as a pair of heated rollers and rollers, a film and rollers, and a belt and rollers are pressed against each other, and a heated object holding an unfixed toner image A permanent image is formed on the recording paper by being introduced into the pressure contact portion formed between the rotating bodies and heated and melted, and then cooled and solidified.

  The rotating body on the side to which the surface of the heated body that holds the unfixed toner contacts is called a fixing member, and is called a fixing roller, a fixing film, a fixing belt, or the like depending on the form. In particular, recently, a belt heating type device has been put into practical use from the viewpoint of quick start and energy saving, and a heat fixing device using an electromagnetic induction heating method for generating heat from the metal base layer itself has also been proposed (for example, Patent Document 1). , 2).

  In an electromagnetic induction heating type fixing device, a cylindrical fixing belt as a rotating body is driven by pressurizing a fixing belt that is pressed by a belt guide member that guides the inner peripheral surface of the fixing belt and a pressure roller. Many methods are employed in which the roller is driven and rotated by rotational driving.

  Such a belt inner surface sliding type heat fixing device has a heavy load during driving. In order to reduce this driving load, it is important to reduce the dynamic frictional resistance between the inner surface of the belt and its supporting member, and a lubricant such as heat-resistant grease is interposed between the inner surface of the belt and its supporting member. Therefore, slidability is ensured (see, for example, Patent Document 3).

  In addition, a method of providing a sliding member on a portion of the belt guide that slides on the inner surface of the fixing belt has been proposed (see, for example, Patent Document 4).

Japanese Utility Model Publication No. 51-109739 Japanese Patent Laid-Open No. 07-114276 Japanese Patent Laid-Open No. 05-027619 JP 2001-042670 A

  However, there are the following problems when the low-speed printing such as the gloss mode and the OHT mode is performed in the fixing device using the belt as described above.

  That is, during low-speed printing, the viscosity resistance of the grease applied to ensure slidability increases and the driving load increases, and the belt rotates slowly, thereby improving the adhesion between the sliding member and the belt inner surface. Therefore, there arises a problem that the rotation of the belt is difficult to follow the rotation of the roller.

  Specifically, the above problem may be accompanied by the occurrence of low-frequency sound due to the occurrence of minute chatter called stick-slip in the state where the sliding resistance between the belt inner surface and the sliding member is high, especially during low-speed rotation. Such a stick-slip phenomenon occurs when the pressure is low and the pressure is high, and is contrary to the means for achieving high pressure and high temperature fixing necessary for improving color image quality.

  As described above, the heat fixing device of a color image forming apparatus that fixes a full color image with a large amount of toner is larger than the conventional monocolor fixing device in order to improve the transparency of the gloss mode and the OHT image. Since it is necessary to apply the pressing force to the nip portion, the surface pressure between the belt inner surface and the pressure pressing member in the nip portion becomes larger, and the sliding resistance becomes larger. Therefore, the stick slip as described above becomes a very big problem in color image formation.

  Therefore, an object of the present invention is to reduce high-frequency sound caused by stick-slip in a fixing device using a belt having a metal base layer.

  In order to achieve the above object, the invention described in claim 1 is a multi-layered endless belt composed of a metal base layer and a resin layer, and molybdenum disulfide is blended in polyamideimide resin on the innermost surface in an amount of 20 wt% or more and less than 30 wt%. It has a heat resistant and wear resistant resin layer.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the heat-resistant and wear-resistant sliding layer has a surface roughness (Rz) of 0.3 μm or more and 5.0 μm or less.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the heat and abrasion resistant resin layer is formed with a thickness of 1 μm or more and 20 μm or less.

  According to a fourth aspect of the present invention, there is provided a belt-like rotator, a guide member that is disposed on an inner peripheral portion of the rotator, and rotatably holds the rotator, and is fitted into the guide member and formed on an inner surface of the rotator. A sliding member that slides, a pressure member that presses against the sliding member via the rotating body to form a fixing nip portion, and raises the temperature of the rotating body, and the fixing as the rotating body rotates A heating / fixing device having a heating means for heating a material to be heated conveyed in the nip, and applying grease for improving slidability to an interface between the rotating body and the sliding member. It comprised with the endless belt in any one of claim | item 1-3.

According to the present invention, an appropriate amount of molybdenum disulfide is dispersed in polyamideimide on the inner surface of the belt in the heat fixing device configured such that the sliding member is pressed and rubbed against the inner surface of the belt as the belt rotates.
By providing a blended sliding layer, it is possible to properly control and maintain the sliding resistance during rotation and sliding, and to suppress an increase in sliding friction resistance due to internal scraping during paper passing durability. . Therefore, low-frequency chatter noise caused by stick-slip generated between the inner surface of the belt and the sliding member can be reduced, and a quiet heat-fixing device can be provided.

  Embodiments of the present invention will be described below.

  FIG. 1 is a cross-sectional view of a heat fixing apparatus showing an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes an endless belt formed in a cylindrical shape, and has a layer structure shown in FIG. This endless belt will be described later.

  Reference numeral 2 denotes a belt guide member, and the endless belt 1 is fitted on the outside of the belt guide member 2 with a margin. Reference numeral 3 denotes magnetic field generating means disposed inside the belt guide member 2 and is composed of an exciting coil and a T-type magnetic core.

  Reference numeral 5 denotes a pressure roller as a pressure member that is rotatably supported and presses against the sliding member 4 via the endless belt 1. The pressure roller 5 is driven to rotate by a driving means (not shown). It also functions as a drive roller that drives the motor. The pressure roller 5 is provided with a heat-resistant elastic layer 5b formed by foaming silicone rubber, fluorine rubber, or silicone rubber on a core metal 5a such as aluminum or iron, and is separated from the outer periphery of the rubber layer 5b. A layer 5c such as a fluororesin is provided as a mold layer.

  Reference numeral 4 denotes a sliding member fitted integrally with the belt guide member 2, which slides on the inner surface of the endless belt 1 and presses against the pressure roller 5 through the endless belt 1 to form a fixing nip portion N. To do.

  The endless belt 1 slides against the lower surface of the sliding member 4 in the clockwise direction by the counterclockwise rotation of the pressure roller 5 at least during image fixing, and thus the endless belt 1 carries a predetermined peripheral speed, that is, an unfixed toner image T. The recording material P, which is a heating material, is driven to rotate at substantially the same speed as the conveyance speed of the recording material P.

  FIG. 2 is a schematic diagram of the layer structure of the endless belt of the present invention.

  The endless belt of the present embodiment is formed on the metal base layer 11 having electromagnetic induction heat generation, the elastic layer 12 laminated on the outer surface, the release layer 13 laminated on the outer surface, and the inner surface of the metal base layer. It has a multilayer structure composed of the sliding layer 10. An adhesive layer may be provided between each layer in order to provide adhesive performance.

  In the endless belt 1 having a substantially cylindrical shape, the sliding layer 10 in contact with the sliding member is the innermost surface, and the release layer 13 is the outer surface side. When an alternating magnetic flux acts on the heat generating layer 11, an eddy current is generated in the heat generating layer 11, and the heat generating layer 11 generates heat. The heat heats the endless belt 1 through the elastic layer 12 and the release layer 13, and heats the heated material P passing through the fixing nip N to heat and fix the toner image T.

  The endless belt 1 of the present invention can be manufactured, for example, as follows.

  First, the heat generating layer 11 was produced by electrolytic casting of electrolytic nickel. Electrocasting is a type of plating, in which an electrolytic wave is placed around a metal matrix, and a current is passed through it to reduce and deposit metal ions on the matrix, thereby forming a metal crystal around the matrix. Were grown to form a cylindrical metal cylinder. In this example, a nickel layer, which is a heat generating layer having an inner diameter of 34 mm and a thickness of 50 μm, is formed, but the present invention is not limited to this.

  Next, a silicone rubber material blended so as to exhibit predetermined physical properties after curing is provided on the heat generating layer 11 in which an adhesive has been uniformly applied and dried on the outer surface in advance so as to have a predetermined thickness, and then heat-cured to form silicone. The rubber elastic layer 12 is formed. The predetermined physical properties after curing can be adjusted by blending fillers such as quartz, alumina and zinc oxide.

  Next, the PFA tube release layer 13 having a predetermined thickness and an inner diameter substantially equal to the outer diameter of the belt with the silicone rubber elastic layer is coated on the silicone rubber elastic layer 12. In this example, a 50 μm PFA tube is coated as a release layer, but it may be formed by a coating method using a fluororesin dispersion.

  Next, a coating liquid in which a predetermined amount of polyamideimide resin and molybdenum disulfide is dispersed in dioxane and dimethylacetamide solvent on the innermost surface is applied to a thickness of 1 μm or more and 20 μm or less by a spray coating method. After drying in a warm air drying furnace for 30 minutes, the temperature is raised to 190 ° C. and baked for 60 minutes to form the sliding layer 10. Finally, the end portion is cut into a predetermined length to thereby cut the endless belt 1. Obtained.

  If the thickness of the sliding layer is less than 1 μm, defects will occur in the layer, and if it exceeds 20 μm, dripping of the coating liquid will occur, making coating difficult.

  In this example, the elastic layer 12 and the release layer 13 are formed on the outer surface of the heat generating layer 11, and finally the sliding layer 10 is formed on the innermost surface. However, the order of forming each layer is not limited to this. Absent.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited to a following example.

  A 300 μm-thick silicone rubber elastic layer 12 is coated on the electroformed nickel belt base layer 11 adjusted to an inner diameter of 34 mm, a thickness of 50 μm, and a length of 300 mm, and cured by heating, and then the 50 μm PFA tube release layer 13 is formed. Coating was performed.

  The sliding layer 10 was formed on the inner surface by the following method.

  First, a belt was set and fixed inside an aluminum pipe having an inner diameter substantially the same as the outer diameter of the belt, and a mechanism capable of rotating the aluminum pipe at a predetermined rotation speed was obtained.

  On the other hand, the coating liquid A for the sliding layer maintained at a predetermined concentration is filled into an WAIST-21818 single-angle automatic gun (spray gun) manufactured by Anest Iwata Co., Ltd., and the tip of the gun is made of aluminum pipe at a constant speed. It was allowed to move in equilibrium with the pipe so as not to contact the inner surface of the coating, and coating was performed a predetermined number of times while spraying. A schematic diagram is shown in FIG.

Specifically, the composition of the coating liquid A was 45% by weight of dioxane, 35% by weight of dimethylacetamide, 14% by weight of polyamideimide resin (PAI), and 6% by weight of molybdenum disulfide (moS ₂ ).

  After coating, the belt was set in an aluminum pipe and placed in a circulating hot air drying furnace adjusted to 80 ° C., dried for 30 minutes, then heated to 190 ° C. and baked for 60 minutes. The belt (1) was obtained by cooling to room temperature and cutting | disconnecting to predetermined length.

  The surface roughness (Rz) of the inner surface sliding layer 10 in the belt (1) thus obtained is adjusted to 5.5 μm, the thickness is adjusted to 10.8 μm, and the amount of molybdenum disulfide is 30 wt%.

  For performance evaluation, this belt (1) is mounted with 0.8 g of grease applied to the fixing unit of a color laser printer LBP-2510 manufactured by Canon Inc., and rotated at a normal process speed of 1/3. In the mode, a sheet passing test of 100 solid black images formed on the OHT sheet was performed, but no abnormal noise due to stick-slip was confirmed in the belt (1).

  Furthermore, after passing 100,000 sheets of plain paper, a test was conducted again for 100 solid black images formed on the OHT sheet in the OHT print mode. Was not recognized. The results are shown in Table 1.

  The liquid composition for the inner sliding layer was adjusted to 45% by weight of dioxane, 35% by weight of dimethylacetamide, 16% by weight of polyamideimide resin, and 4% by weight of molybdenum disulfide. This was applied to the inner surface of the base layer in the same manner as in Example 1, dried and baked to form a sliding layer, and cut to obtain a belt (2).

  In the belt (2) thus obtained, the surface roughness (Rz) of the inner sliding layer 10 is adjusted to 0.2 μm, the thickness is adjusted to 2.3 μm, and the amount of molybdenum disulfide is 20 wt%.

  The belt (2) thus produced was mounted on the fixing unit in the same manner as in Example 1, and the initial stick-slip test and the stick-slip test after the 100,000 sheet passing test were conducted. Obtained. The results are shown in Table 1.

  The liquid composition for the inner surface sliding layer was adjusted to 45 wt% dioxane, 35 wt% dimethylacetamide, 15 wt% polyamide imide resin, and 5 wt% molybdenum disulfide. This was applied to the inner surface of the base layer in the same manner as in Example 1, dried and baked to form a sliding layer, and cut to obtain a belt (3).

  In the belt (3) thus obtained, the surface roughness (Rz) of the inner sliding layer 10 is adjusted to 0.5 μm, the thickness is adjusted to 4.5 μm, and the amount of molybdenum disulfide is 25 wt%. .

  Mount this belt (3) on the fixing unit in the same manner as in Example 1 with the grease amount reduced to 0.2 g, and perform the initial stick-slip test and the stick-slip test after the 100,000 sheet passing test. However, all gave good results. The results are shown in Table 1.

  Using the coating liquid C prepared in Example 3, this was applied to the inner surface of the base layer in the same manner as in Example 1, dried and baked to form a sliding layer, and then the belt ( 4) was obtained.

  In the belt (4) thus obtained, the surface roughness (Rz) of the inner sliding layer 10 is adjusted to 4.5 μm, the thickness is adjusted to 9.4 μm, and the amount of molybdenum disulfide is 25 wt%.

  This was mounted on the fixing unit in the same manner as in Example 3 with the amount of grease applied reduced to 0.2 g, and the initial stick-slip test and the stick-slip test after the 100,000 sheet passing test were conducted. Good results were obtained. The results are shown in Table 1.

<Comparative Example 1>
The liquid composition for the inner surface sliding layer was adjusted to 45% by weight of dioxane, 35% by weight of dimethylacetamide, and 20% by weight of polyamideimide resin. This was applied to the inner surface of the base layer in the same manner as in Example 1, dried and baked to form a sliding layer, and cut to obtain a belt (5). In the belt (5) thus obtained, the inner surface sliding layer 10 has a surface roughness (Rz) of 1.0 μm and a thickness of 8.8 μm.

  When this belt (5) was mounted on the fixing unit in the same state as in Example 1 and an initial stick-slip test was performed, generation of abnormal noise due to stick-slip was observed. The results are shown in Table 1.

<Comparative example 2>
The liquid composition for the inner surface sliding layer was adjusted to 45 wt% dioxane, 35 wt% dimethylacetamide, 12 wt% polyamideimide resin, and 8 wt% molybdenum disulfide. This was applied to the inner surface of the base layer in the same manner as in Example 1, dried and baked to form a sliding layer, and cut to obtain a belt (6).

  In the belt (6) thus obtained, the inner surface sliding layer 10 has a surface roughness (Rz) adjusted to 4.0 μm, a thickness of 12.8 μm, and the amount of molybdenum disulfide is 40 wt%.

When this belt (6) was mounted on the fixing unit in a state where the amount of grease applied was 0.2 g in the same manner as in Example 3, and an initial stick-slip test was performed, almost no abnormal noise was observed. . However, after passing 100,000 sheets of plain paper again, a paper passing test of 100 solid black images formed on the OHT sheet was performed again in the OHT print mode. The occurrence of abnormal noise at the time of stick-slip, which was supposed to occur, was observed. The results are shown in Table 1.

FIG. 2 is a schematic view of a fixing device in the present embodiment. It is the schematic of the layer structure of the endless belt in this Embodiment. It is the schematic of belt inner surface sliding layer coating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endless belt 2 Belt guide 3 Core coil 4 Sliding member 5 Pressure roller 5a Core metal 5b Heat-resistant elastic layer 5c Release layer 10 Sliding layer 11 Metal base layer 12 Elastic layer 13 Release layer

Claims (4)

In an endless belt having a multilayer structure composed of a metal base layer and a resin layer,
An endless belt comprising a heat-resistant and wear-resistant resin layer in which 20 wt% or more and less than 30 wt% of molybdenum disulfide is blended in polyamide-imide resin on the innermost surface.   2. The endless belt according to claim 1, wherein the heat-resistant and wear-resistant sliding layer has a surface roughness (Rz) of 0.3 μm or more and 5.0 μm or less.   The endless belt according to claim 1 or 2, wherein the heat-resistant and wear-resistant resin layer is formed with a thickness of 1 µm or more and 20 µm or less. A belt-like rotator, a guide member that is disposed on the inner periphery of the rotator and rotatably holds the rotator, and a sliding member that is fitted into the guide member and slides on the inner surface of the rotator. A pressure member that presses against the sliding member via the rotating body to form a fixing nip portion, and a temperature to be heated, and the heated body that is conveyed through the fixing nip as the rotating body rotates. A heating fixing device having a heating means for heating the material, and applying grease for improving slidability on an interface between the rotating body and the sliding member;
A heat fixing device, wherein the rotating body is constituted by the endless belt according to claim 1.

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