JP2005157175A - Fixing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing member in which an elastic layer has both heat conductivity and elastic effect and which is advantageous in heat resistance as member constitution. <P>SOLUTION: The fixing member which fixes toner for electrophotography is formed by laminating an elastic layer 1 and an elastic layer 2 in order on a base and further forming the outermost layer. Here, the heat diffusivity a1 of the elastic layer 1 at 25°C and the heat diffusivity of the elastic layer 2 at 25°C, and the layer thickness d1 of the elastic layer 1 and the layer thickness d2 of the elastic layer 2 fall within prescribed ranges. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is an invention of a fixing member suitable for a roller or a belt member used for toner fixing of an electrophotographic copying machine or printer.

  In toner fixing in an electrophotographic process, a fixing member in which a fluororesin having good toner release is formed as an outermost layer is widely used. In particular, fixing members that have the outermost layer of fluororesin formed directly or indirectly on an elastic layer made of a flexible elastic material such as silicone rubber are used in various variations due to demands for higher image quality and higher functionality. Yes.

  The elastic layer is required to have various thermal characteristics as a fixing member simultaneously with its elastic function. Generally, a heat conductive inorganic raw material is blended with a heat resistant rubber raw material such as silicone rubber to obtain desired thermal characteristics and elasticity. However, adding a large amount of an inorganic filler to give high thermal conductivity is a direction that impairs the elasticity of the rubber, and various measures are required for the rubber raw material and the inorganic filler.

  For example, Patent Document 1 and Patent Document 2 are inventions related to materials that improve the low rebound resilience that occurs when a conventional inorganic filler such as alumina powder or silica powder is blended with silicone rubber. In addition, as disclosed in Patent Document 3, an invention that uses an inorganic filler such as zinc oxide to provide a composition excellent in flame retardancy and creep resistance is also known.

  In addition, it is already known that the rubber hardness is increased by blending such an inorganic filler. For example, as disclosed in Patent Document 4, the crosslinking density is lowered to reduce the hardness of the rubber. In general, a method for reducing the filler is known, and an invention related to a material for improving the same has been proposed as described in the publication.

  That is, when the thermal conductivity is enhanced as a material property, there are many cases where the performance is inferior in the elastic effect and the heat resistance. In other words, it can be said that there are many cases in which heat conduction characteristics must be sacrificed when enhancing the elastic effect and heat resistance.

There are many inventions from the viewpoint of material improvement for such problems, and specific solutions are widely available. However, when further improvement is desired, the invention from the viewpoint of the design and configuration of the fixing member Will also be needed.
Japanese Patent Laid-Open No. 11-158383 Japanese Unexamined Patent Publication No. 2002-072728 Japanese Patent Registration No.03235863 Special Registration No. 03243991

  An object of the present invention is to provide a fixing member that achieves both heat conduction characteristics and elastic effects in an elastic layer and is advantageous in heat resistance characteristics as a member structure.

  The first invention according to the present application is to provide a fixing member that melts toner more by high thermal conductivity and is advantageous in heat resistance as a member structure for toner fixing. In particular, it is an object of the present invention to solve the above problems in a fixing member that requires a relatively thin elastic layer from the viewpoint of heat capacity of the fixing member.

  The second invention according to the present application aims to provide a fixing member that solves the above-mentioned problems while selecting a material having relatively high heat resistance.

  The third invention according to the present application is to provide a fixing member that solves the above problems while enhancing the elastic effect of the elastic layer and ensuring the uniformity of the fixed image.

In order to achieve the above object, according to a first invention of the present application, as a fixing member for fixing an electrophotographic toner, an elastic layer 1 and an elastic layer 2 are sequentially laminated on a substrate, and an outermost layer is formed. The thermal diffusivity a1 [m ² / s] of the elastic layer 1 at 25 ° C. is set to 0.1 × 10 ⁻⁶ ≦ a1 ≦ 0.4 × 10 ⁻⁶ and elasticity at 25 ° C. The thermal diffusivity a2 [m ² / s] of the layer 2 is 0.6 × 10 ⁻⁶ ≦ a2 ≦ 0.9 × 10 ⁻⁶ , the layer thickness of the elastic layer 1 is d1 [μm], and the layer thickness of the elastic layer 2 When d2 [μm], 100 ≦ d1 ≦ 400, 100 ≦ d2 ≦ 400, and 200 ≦ (d1 + d2) ≦ 500, the first object is achieved.

  In this way, by making the thermal diffusivity of the elastic layer close to the substrate relatively low, it is possible to select a material advantageous in heat resistance characteristics, and by making the thermal diffusivity of the elastic layer close to the outermost layer relatively high Further, it is possible to improve the heat conduction property to the toner. According to the present invention, a more favorable effect could be confirmed in the above configuration.

  In addition to the first invention, the second invention according to the present application achieves the second object by using the outermost layer as a fluororesin and the elastic layer as a silicone rubber.

  In addition to the second invention, the third invention according to the present application has a JIS-A hardness HS1 of the silicone rubber layer 1 at 25 ° C. of 1 ° ≦ HS1 ≦ 10 ° and a silicone at 25 ° C. The third object is achieved by setting the JIS-A hardness HS2 of the rubber layer 2 to 20 ° ≦ HS2 ≦ 40 °.

  According to the present invention, it has been possible to provide a design means that achieves both a heat conduction characteristic and an elastic effect in the elastic layer and is advantageous in heat resistance as a member structure.

  Hereinafter, toner fixing members embodying the present invention will be exemplified.

FIG. 1 shows an example of a toner fixing member.
11 is a roll-shaped metal core, and a material such as aluminum or iron, which has a relatively high thermal conductivity and can ensure rigidity, is selected. A heat source such as a halogen heater (not shown) is disposed in the hollow interior and heated.
Reference numerals 12 and 13 denote elastic layers, which are required to have heat resistance and flexibility. The material is not particularly limited, but silicone rubber is suitable from the viewpoint of heat resistance, elasticity, and cost.
The type of the silicone rubber is not particularly limited as the form of the crosslinking reaction, but an addition reaction type or a peroxide reaction type is preferably used in view of use in the toner fixing member.

  In particular, addition-reaction type silicone rubber is a material that can carry out the present invention more effectively due to incidental convenience such as ease of processing.

  Further, various types of functional groups are known for silicone rubber, but silicone rubbers having these known types of functional groups may be used. In particular, dimethyl silicone rubber having only a methyl group, and methyl phenyl silicone rubber / phenyl silicone rubber having a phenyl group are well known and preferably used for toner fixing members.

  The silicone rubber may be blended with an inorganic powder filler for the purpose of heat resistance, heat transfer, reinforcement, increase in weight, and the like. Known inorganic fillers can be used. Examples thereof include crystalline silica, fumed silica, iron oxide, and alumina.

  In addition, a compounding agent may be added to the silicone rubber for adjusting various properties.

  The design of this elastic layer is particularly important from the viewpoint of heat conduction characteristics. The present invention focuses on the thermal diffusivity a of the material in order to design the thermal conductivity in a short time. The thermal diffusivity a is a physical constant defined by a = k / (ρ · c). Here, k is thermal conductivity, ρ is density, and c is specific heat. In the present invention, the thermal conductivity k was measured with a rapid thermal conductivity meter (QTM-500, manufactured by Kyoto Electronics Industry Co., Ltd.). The density ρ was measured with a solid specific gravity measuring device (SGM-200, manufactured by Shimadzu Corporation). The specific heat c was measured with a differential calorimeter (DSC2920, manufactured by PA Instruments). The measurement conditions were 25 ° C., and measurement was performed by preparing a measurement sample of silicone rubber according to each apparatus.

The elastic layer 1 (12 shown in the figure) has a thermal diffusivity a1 [m ² / s] at 25 ° C. of 0.1 × 10 ⁻⁶ ≦ a1 ≦ 0.4 × 10 ⁻⁶ and is expected to exhibit mainly an elastic effect. . In the present invention, the layer thickness d1 [μm] of the elastic layer 1 is set to a thickness of 100 μm or more so that the elastic effect can be sufficiently exerted, and in the range of 400 μm or less from the viewpoint of the thermal characteristics of the fixing member. . Further, when more preferable elastic effect and heat resistance are expected, when the elastic layer 1 is a silicone rubber, the JIS-A hardness HS1 is set to 1 ° or more and 10 ° or less. Here, the JIS-A hardness is a value measured at 25 ° C. according to JIS-K-6301.

Elastic layer 2 (13 in the figure) has a thermal diffusivity a2 [m ² / s] at 25 ° C. of 0.6 × 10 ⁻⁶ ≦ a2 ≦ 0.9 × 10 ⁻⁶ and is expected to exhibit mainly an elastic effect. . In the present invention, the layer thickness d2 [μm] of the elastic layer 2 has a thickness of 100 μm or more so that the thermal conductivity characteristics can be sufficiently exhibited, and from the viewpoint of the thermal characteristics of the fixing member, To do. In addition, when a more preferable elastic effect and heat resistance are expected, when the elastic layer 2 is a silicone rubber, the JIS-A hardness HS2 is set to 20 ° to 40 °.

  In addition, the total thickness of the elastic layer (d1 + d2) is 200 μm or more in view of the elastic effect and the effect of the present invention more effectively, and more efficient heat conduction from the heating source is 500 μm or less. And

  Reference numeral 14 denotes an outermost layer, which is required to have heat resistance and difficulty in toner adhesion. The material is not particularly limited, but considering the characteristics of various fixing members, fluororesin is a material that can more effectively implement the present invention.

  The kind of fluororesin can be a known kind of material, and is not particularly limited. Commonly known single or complex species such as polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP) It is preferable to use a material.

  The thickness of the fluororesin as the outermost layer is not particularly limited, but in the thickness range of 50 μm or less, the effect of the present invention can be expected more effectively, and more preferably 30 μm or less is particularly preferred as an embodiment of the present invention. Recommended. The lower limit of the thickness varies with the demand for mechanical strength, but it is considered practical to set the thickness to 10 μm or more.

  The embodiment of the present invention may be not only the roller-shaped toner fixing member shown in FIG. 1 but also a belt shape made of a thin substrate.

(Example)
First, an addition reaction type two-component liquid silicone rubber raw material was prepared for the practice of the present invention.

As silicone rubber 1, a liquid silicone rubber raw material having an average viscosity of two liquids of 20 Pa · s was prepared. When the physical properties of the silicone rubber raw material after thermosetting were measured, the thermal diffusivity a = 0.1 × 10 ⁶ m ² / s and the JIS-A hardness HS = 5 °.

As the silicone rubber 2, a liquid silicone rubber raw material having an average viscosity of two liquids of 290 Pa · s was prepared. When the physical properties of the silicone rubber raw material after thermosetting were measured, the thermal diffusivity a = 0.8 × 10 ⁶ m ² / s and the JIS-A hardness HS = 30 °.

As silicone rubber 3, a liquid silicone rubber raw material having an average viscosity of two liquids of 220 Pa · s was prepared. When the physical properties of the silicone rubber raw material after thermosetting were measured, the thermal diffusivity a = 0.4 × 10 ⁶ m ² / s and the JIS-A hardness HS = 10 °.

As the silicone rubber 4, a liquid silicone rubber raw material having an average viscosity of two liquids of 120 Pa · s was prepared. When the physical properties of the silicone rubber raw material after thermosetting were measured, the thermal diffusivity a = 0.6 × 10 ⁶ m ² / s and the JIS-A hardness HS = 33 °.

(Example 1)
First, an aluminum pipe (roller) having an outer diameter of 30 mm, a thickness of 1.5 mm, and a length of 230 mm was prepared, and the surface was primed with a silicone-based primer (DY35-051, manufactured by Toray Dow Corning Silicone).

  Next, the silicone rubber 1 stock solution is weighed and stirred, and uniformly coated to a thickness of 100 μm on the primer-treated aluminum pipe, and then the silicone rubber 2 stock solution is weighed and stirred to a uniform thickness of 200 μm. did. This roller was treated in a hot stove at 150 ° C. for 30 minutes, and then treated in a hot stove at 200 ° C. for 4 hours.

  Next, a heat-shrinkable PFA fluororesin tube having a thickness of 30 μm and an inner diameter of 30.8 mm and having a defluorinated inner surface was prepared, and the silicone primer was applied to the inner surface and air dried.

  Subsequently, the roller coated with the silicone rubber was covered with the air-dried PFA fluororesin tube and treated in a hot air oven at 200 ° C. for 4 hours to finish the molding as a roller.

(Example 2)
A roller was produced in the same manner as in Example 1 except that the thickness of the silicone rubber 1 was 200 μm and the thickness of the silicone rubber 2 was 100 μm.

(Example 3)
A roller was produced in the same manner as in Example 1 except that silicone rubber 3 was used instead of silicone rubber 1 and silicone rubber 4 was used instead of silicone rubber.

(Comparative Example 1)
First, an aluminum pipe (roller) having an outer diameter of 30 mm, a thickness of 1.5 mm, and a length of 230 mm was prepared, and the surface was primed with a silicone-based primer (DY35-051, manufactured by Toray Dow Corning Silicone).

  Next, the stock solution of silicone rubber 1 is weighed and stirred, and uniformly coated to a thickness of 300 μm on the primer-treated aluminum pipe. This roller is treated in a hot air oven at 150 ° C. for 30 minutes, and then hot air oven It was treated at 200 ° C for 4 hours.

  Thereafter, the outermost layer of fluororesin was formed by the same method as in Example 1 to produce a roller.

(Comparative Example 2)
A roller was produced in the same manner as in Comparative Example 1 except that the silicone rubber 2 was used instead of the silicone rubber 1.

(Comparative Example 3)
A roller was produced in the same manner as in Example 2 except that silicone rubber 2 was used instead of silicone rubber 1 and silicone rubber 1 was used instead of silicone rubber 2.

  In order to confirm the effect of the present invention with respect to the manufactured roller, various manufactured rollers were incorporated in the toner fixing device illustrated in FIG. 2, and the fixed image was evaluated.

  Reference numeral 21 denotes an upper roller having a toner fixing member arranged on the upper side, and reference numeral 22 denotes a lower roller having a toner fixing member arranged so as to be pressed against the upper roller. A heater (not shown) is disposed in the roller, and the temperature is adjusted to a predetermined temperature through a thermistor (not shown).

  The portion sandwiched between the upper and lower rollers is called a toner fixing nip, and a recording material 23 such as paper on which a toner image is formed is nipped and conveyed at a predetermined speed in this nip, and receives heat and pressure, thereby causing toner Is fixed to obtain a fixed image.

  For the toner image, a creative processor 680 (trade name: CP680, Canon Inc.) was used so that the paper could be taken out before the fixing device, and an unfixed toner image was obtained.

  In addition, color laser copier paper (trade name: TKCL-A4, Canon Sales Co., Ltd.) was used as the paper. The image was a two-color solid image in which a magenta density of 100% and a cyan density of 100% were superimposed.

  In the evaluation of the fixed image, the degree of toner melting was evaluated by measuring the glossiness, and superiority or inferiority was given. That is, if the glossiness is high or low for a certain condition, the toner melting is excellent if it is sufficient, and if the glossiness is too low, the toner melting is evaluated as inferior. Based on the superiority or inferiority of the toner melting, the superiority of the heat conduction characteristics as a fixing member, which is the effect of the present invention, was judged. Furthermore, the variation of the glossiness value was evaluated, and the elastic effect which is the effect of the present invention was confirmed. At this time, it was judged that the one with less variation in the glossiness value exhibited a more elastic effect. The glossiness was measured using a glossmeter (PG-3D, incident / reflection angle = 75 °, Nippon Denshoku Co., Ltd.), based on black glass with a glossiness of 96.9.

  The results are shown in FIG. Thus, in the examples of the present invention, the gloss is the same or lower than that using only silicone rubber having relatively good heat conduction characteristics as in Comparative Example 1, but it is sufficient (up to about -2). Thus, the effect of the present invention that the toner has low gloss unevenness and is excellent in toner melting characteristics and elastic effects can be verified.

The illustration figure of embodiment of this invention. FIG. 3 is a schematic diagram of a toner fixing device used for confirming the effect of the present invention. The result of the Example and comparative example of this invention.

Explanation of symbols

11 Core
12 Elastic layer 1
13 Elastic layer 2
14 Outermost layer
21 Upper roller
22 Lower roller
23 Recording material

Claims (3)

A fixing member for fixing toner of electrophotography,
A fixing member in which an elastic layer 1 and an elastic layer 2 are sequentially laminated on a substrate and an outermost layer is formed;
The thermal diffusivity a1 [m ² / s] of the elastic layer 1 at 25 ° C is
0.1 × 10 ^-6 ≦ a1 ≦ 0.4 × 10 ^-6
And the thermal diffusivity a2 [m ² / s] of the elastic layer 2 at 25 ° C. is
0.6 × 10 ^-6 ≦ a2 ≦ 0.9 × 10 ^-6
And
And, when the layer thickness of the elastic layer 1 is d1 [μm] and the layer thickness of the elastic layer 2 is d2 [μm],
100 ≤ d1 ≤ 400
And
100 ≤ d2 ≤ 400
And
200 ≤ (d1 + d2) ≤ 500
A fixing member characterized by satisfying the requirements.   2. The fixing member according to claim 1, wherein the outermost layer is a fluororesin and the elastic layer is a silicone rubber. The fixing member according to claim 2, wherein the silicone rubber layer 1 has a JIS-A hardness HS1 at 25 ° C.
1 ° ≦ HS1 ≦ 10 °
JIS-A hardness HS2 of silicone rubber layer 2 at 25 ° C is
20 ° ≦ HS2 ≦ 40 °
A fixing member characterized by the above.

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