JP2019168676A - Fixing member, fixing device, and electrophotographic image forming apparatus - Google Patents

Abstract

To provide a fixing member that has an outer surface with excellent toner releasability and excellent scratch resistance.SOLUTION: A fixing member has a substrate, an elastic layer, and a mold release layer in this order; the mold release layer contains a tetrafluoroethylene/perfluoroalkylvinylether copolymer, the loss tangent of the mold release layer at a frequency of 10 Hz, 180°C is 5.0×10or more and 3.0×10or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fixing member, a fixing device using the same, and an electrophotographic image forming apparatus including the same.

  Generally, in a fixing device used in an electrophotographic image forming apparatus (hereinafter also referred to as “image forming apparatus”) such as a copying machine or a laser printer, a pair of heated rollers and rollers, a film and rollers, a belt and rollers, a belt And a rotating body such as a belt are pressed against each other. Then, a recording medium such as paper holding an image formed with unfixed toner is introduced into a pressure contact portion (hereinafter referred to as a “fixing nip portion”) formed between the rotating bodies, and the unfixed toner is removed. By heating and melting, the image is fixed on the recording medium. A rotating body that contacts an unfixed toner image on a recording medium is called a fixing member, and is called a fixing roller, a fixing film, or a fixing belt depending on the form.

In a release layer (hereinafter referred to as “release layer”) constituting the outer surface of the fixing member, a fluororesin, specifically, for example, tetrafluoroethylene / partite is used in order to suppress toner adhesion. A release layer containing a fluoroalkyl vinyl ether copolymer (hereinafter also referred to as “PFA”) may be used.
Patent Document 1 describes that the low wear resistance of a release layer containing a fluororesin used for a heat fixing roller can be improved by a release layer containing a filler such as carbon black together with the fluororesin. . However, it is also described that such a filler is inferior in releasability compared to a release layer not containing a filler because such a filler has a lower releasability than a fluororesin.

JP 2000-198979 A

“Journal of the Adhesion Society of Japan”, Adhesion Society of Japan, 1972, Vol. 8, No. 3, p. 131-141

  As disclosed in Patent Document 1, it is preferable not to include a filler in order to ensure high toner releasability on the surface of a release layer containing a fluororesin. On the other hand, a release layer made of only a fluororesin has low scratch resistance.

One aspect of the present invention is directed to providing a fixing member capable of achieving both toner release properties and scratch resistance at a high level.
Another aspect of the present invention is directed to providing a fixing device that contributes to stable formation of high-quality electrophotographic images. Furthermore, another aspect of the present invention is directed to providing an electrophotographic image forming apparatus capable of forming a high-quality electrophotographic image.

According to one aspect of the present invention, there is provided a fixing member having a base material, an elastic layer, and a release layer in this order, and the release layer comprises a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer. And a fixing member having a loss tangent of 5.0 × 10 ^{−2 to} 3.0 × 10 ⁻¹ at a frequency of 10 Hz and 180 ° C. of the release layer.
According to another aspect of the present invention, a fixing device including the fixing member and an electrophotographic image forming apparatus including the fixing device are provided.

  According to one aspect of the present invention, it is possible to obtain a fixing member having an outer surface having excellent toner releasability and excellent scratch resistance. According to another aspect of the present invention, a fixing device and an electrophotographic image forming apparatus that contribute to stable formation of high-quality electrophotographic images can be obtained.

Sectional schematic diagram of the fixing belt (A) and the fixing roller (B) as an example of the present invention Schematic cross-sectional view of a fixing device using a fixing belt according to the present invention. Schematic cross-sectional view of a fixing device using a fixing roller according to the present invention. Schematic cross-sectional schematic diagram showing one embodiment of the electrophotographic image forming apparatus of the present invention

The present inventors provide a fixing member including a release layer that includes PFA and has a loss tangent of 5.0 × 10 ⁻² or more and 3.0 × 10 ⁻¹ or less at a frequency of 10 Hz and a temperature of 180 ° C. Thus, it has been found that toner releasability and scratch resistance can be achieved at a high level.
A release layer exhibiting such a loss tangent value is considered to have a strong force to dissipate the force received from the outside and easily restore the original shape even if it is deformed once. Therefore, it is considered that high scratch resistance can be achieved.

  And it discovered that such a physical property could be achieved by increasing the molecular mobility of the polymer chain of PFA in a release layer, for example. That is, even if a filler such as carbon black is not contained in the release layer, a release layer having the above physical properties can be obtained. Therefore, the release layer exhibiting the above physical properties can maintain the original high toner release property of the fluororesin.

  The increase in molecular mobility of the polymer chain of PFA for achieving the above physical properties is, for example, referred to as a “fluorinated polymer compound” (hereinafter simply referred to as “fluorinated polymer compound”) different from PFA in the release layer. ) In such a way that it can interact with the polymer chain of PFA.

  Since PFA has a small surface free energy, it is hardly compatible with other fluorine-containing polymer compounds. Therefore, it seemed difficult to mix the PFA and the fluorine-containing polymer compound without causing phase separation. However, as a result of the study by the present inventors, in a state where PFA in a molten state and an oily fluorine-containing polymer compound are mixed, kneading by applying strong shearing, PFA and fluorine-containing polymer compound Has been found to be a chemically stable mixture without phase separation.

It is considered that the PFA in the molten state is unwound in a chain shape including the crystal region. In that state, the fluorine-containing polymer compound having similarity in molecular structure with PFA exists in a compatible state or a state in which the fluorine-containing polymer compound is finely dispersed in PFA. Therefore, in a range from room temperature (for example, 25 ° C.) to an actual use temperature range of the fixing member (for example, 100 to 250 ° C.), the PFA and the fluorine-containing polymer compound in the release layer do not undergo phase separation, It is considered that a state where the molecular compound and PFA are chemically and stably mixed can be realized.
In this state, when the fluorine-containing polymer compound decreases the crystallinity of PFA and interacts with the amorphous region, the loss tangent of the release layer at a frequency of 10 Hz and a temperature of 180 ° C. is 5 It is thought that it may have a high value of 0.0 × 10 ⁻² or more and 3.0 × 10 ⁻¹ or less.

In addition, in order to improve the flexibility of PFA, a method of increasing the ratio of a perfluoroalkyl vinyl ether (hereinafter also referred to as “PAVE”) as a copolymer component is known. Even if PFA produced by this method is used, a release layer having a loss tangent at a frequency of 10 Hz and a temperature of 180 ° C. within a range of 5.0 × 10 ^{−2 to} 3.0 × 10 ⁻¹ is obtained. I couldn't.

  Hereinafter, a fixing member and a fixing device of the present invention will be described in detail based on specific configurations.

1. Fixing Member FIGS. 1A and 1B are cross-sectional views showing different aspects of the fixing member according to the present invention. 1A is a fixing member having an endless belt shape (hereinafter also referred to as “fixing belt 11”), and FIG. 1B is a roller-shaped fixing member (hereinafter also referred to as “fixing roller 12”). Designated).
The fixing member according to FIGS. 1A and 1B includes a base material 13, an elastic layer 14 covering the periphery thereof, and a release layer 15 covering the surface thereof. The release layer 15 may be bonded to the peripheral surface of the elastic layer 14 with an adhesive layer (not shown).

(1) Base material As a material of the base material 13, metals and alloys such as aluminum, iron, stainless steel, and nickel, and heat resistant resins such as polyimide are used.

  In the fixing belt 11, a base material having an endless belt shape is used as the base material 13. Examples of the material of the base material 13 include materials having excellent heat resistance such as nickel, stainless steel, and polyimide. Although it does not specifically limit as thickness of this base material 13, For example, it is preferable to set it as 20-100 micrometers from a viewpoint of intensity | strength, a softness | flexibility, and a heat capacity.

  In the fixing roller 12, for example, a solid or hollow metal core is used as the base material 13. Examples of the material of the metal core include metals such as aluminum, iron, and stainless steel, and alloys. In the case of using a hollow cored bar, a heat source can be provided inside.

  A surface treatment may be performed on the outer surface of the base material 13 in order to provide adhesion with the elastic layer 14. For the surface treatment, physical treatment such as blasting, lapping and polishing, chemical treatment such as oxidation treatment, coupling agent treatment and primer treatment can be used singly or in combination.

  When the elastic layer 14 containing silicone rubber is provided on the surface of the base material 13, a primer treatment is performed on the surface of the base material 13 in order to improve the adhesion between the base material 13 and the elastic layer 14. Is preferred. Examples of the primer used for the primer treatment include a paint in which a coloring agent such as a silane coupling agent, a silicone polymer, a hydrogenated methylsiloxane, an alkoxysilane, a reaction promoting catalyst, or a bengara is appropriately blended and dispersed in an organic solvent. It is done.

  The primer can be appropriately selected depending on the material of the substrate 13, the type of the elastic layer 14, or the form of the crosslinking reaction. In particular, when the elastic layer 14 contains a large amount of unsaturated aliphatic groups, a primer containing a hydrosilyl group is preferably used in order to impart adhesiveness by reaction with the unsaturated aliphatic group. When the elastic layer 14 contains many hydrosilyl groups, a primer containing an unsaturated aliphatic group is preferably used. In addition to the above, a primer containing an alkoxy group is also included. A commercially available primer can be used. In addition, the primer treatment includes a step of applying this primer to the surface of the substrate 13 (adhesive surface with the elastic layer 14) and drying or baking.

(2) Elastic layer The material constituting the elastic layer 14 is preferably a heat-resistant rubber such as silicone rubber or fluorine rubber, and is preferably an addition-curing type silicone rubber.

  The thickness of the elastic layer 14 can be appropriately designed in consideration of the surface hardness of the fixing member and the width of the fixing nip portion to be formed. When the fixing member is the fixing belt 11, the thickness of the elastic layer 14 is preferably 100 μm or more and 500 μm or less, and more preferably 200 μm or more and 400 μm or less.

  When the fixing member is the fixing roller 12, the thickness of the elastic layer 14 is preferably 100 μm or more and 3 mm or less, more preferably 300 μm or more and 2 mm or less. By setting the thickness of the elastic layer 14 within this range, it is possible to secure a sufficient width of the fixing nip portion due to the deformation of the base material 13 when the fixing member is incorporated in the fixing device.

The elastic layer 14 may contain a filler. A filler is added in order to control thermal conductivity, heat resistance, and elastic modulus. Specifically, silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), silica (SiO ₂ ), boron nitride (BN), aluminum nitride (AlN), alumina (Al ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), magnesium oxide (MgO), titanium oxide (TiO ₂ ), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), carbon Examples thereof include black (C), carbon fiber (C), and carbon nanotube (C).

  Moreover, the material which comprises the elastic layer 14 may mix | blend the reaction control agent (inhibitor) called an inhibitor for controlling reaction start time. As the reaction control agent, known substances such as methyl vinyl tetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, and hydroperoxide are used.

(3) Release layer The release layer 15 contains PFA and has a loss tangent of 5.0 × 10 ⁻² or more and 3.0 × 10 ⁻¹ or less at a frequency of 10 Hz and a temperature of 180 ° C. The loss tangent is particularly preferably 7.0 × 10 ⁻² or more and 2.0 × 10 ⁻¹ or less. As described above, it is considered that the release layer 15 exhibiting such a loss tangent value dissipates the force received from the outside and has a strong force to easily restore the original shape even if it is once deformed. Therefore, it is considered that high scratch resistance can be achieved.
The release layer 15 having such physical properties can be achieved by suppressing the molecular mobility of the polymer chain of PFA in the release layer 15. That is, even if the release layer 15 does not contain a filler such as carbon black, the release layer 15 having the above physical properties can be obtained. Therefore, the release layer 15 exhibiting the above physical properties can maintain the original high toner release property of the fluororesin.

<Thickness of release layer>
The thickness of the release layer 15 is preferably 3 μm or more, particularly preferably 10 μm or more, from the viewpoint of suppressing surface abrasion when the fixing member is used. Further, from the viewpoint of suppressing a decrease in thermal conductivity in the thickness direction as a fixing member, 50 μm or less, particularly 30 μm or less is preferable.

Any method can be used for increasing the molecular mobility of the polymer chain of PFA to achieve the above physical properties as long as the molecular mobility of the polymer chain of PFA can be increased. For example, it can be realized by including a fluorine-containing polymer compound in the release layer so that it can interact with the polymer chain of PFA. And the fixing member provided with such a release layer can be obtained through the following (Step 1) to (Step 4), for example.
(Step 1) Pellet-like PFA is stirred and mixed with the fluorine-containing polymer compound to obtain a mixture.
(Step 2) Using a twin screw extruder, the mixture is extruded while melting and kneading at a temperature not lower than the melting point (280 ° C.) of PFA and not higher than 450 ° C. , Referred to as “melt-kneaded product”).
(Step 3) The melt-kneaded material is pelletized, and the pellet is extruded and formed into a tube shape with an extrusion molding machine to obtain a release layer tube.
(Step 4) The outer surface of the elastic layer formed on the substrate is covered with a release layer tube.
With respect to (Step 1) to (Step 4) relating to the production of the release layer, a method using PFPE as the fluorine-containing polymer compound will be described in detail below.

(Process 1)
PFA pellets and PFPE are stirred and mixed in a stirrer at a predetermined ratio to obtain a mixture of PFA and PFPE. The stirring conditions here are not particularly limited. For example, the stirring and mixing may be performed in a state in which the mobility of the polymer chain of PFA and PFPE above the glass transition point (100 ° C.) of PFA and PFPE is increased. preferable. Further, it is more preferable to pulverize the PFA pellets in a powder form, increase the specific surface area, and mix in a state where the contact area with PFPE is increased.

(Process 2)
Pellets of the mixture obtained in step 1 are put into a twin screw extruder, heated to a temperature higher than the melting point of PFA, for example, 280 ° C. or higher and 450 ° C. or lower, and kneaded under predetermined conditions while melting PFA. . In particular, it is more preferable to heat at 330 ° C. or higher and 350 ° C. or higher in order to increase the mobility of the polymer chain of PFA and enhance the interaction with PFPE. Moreover, in order to suppress thermal decomposition, it is preferable to heat at 420 degrees C or less.
In order to effectively apply shear, L / D (L: screw length, D: screw diameter) is preferably 10 or more and 100 or less. Further, the screw rotation speed is preferably 100 to 1000 rpm, and it is more preferable to use a screw provided with grooves or notches in the kneading element.

  In Step 2, the state in which PFPE is mixed with molten PFA has a lower melt viscosity than the state in which only PFA is melted. Therefore, it is possible to set the temperature at the time of extrusion lower than extruding the melt of PFA alone.

  Moreover, the interaction between PFA and PFPE can be further enhanced by melt-kneading the obtained melt-kneaded material again with a twin-screw extruder.

(Process 3)
The melt-kneaded product obtained in step 2 is cut into pellets, and the obtained pellets are molded into a tube shape by an extrusion molding machine to obtain a release layer tube.

  The elastic layer and the release layer may be bonded by an adhesive layer. As the adhesive layer, a thermosetting silicone rubber adhesive is preferably used.

  The storage elastic modulus E ′ at a frequency of 10 Hz and a measurement temperature of 180 ° C. is preferably 5.0 MPa or more and 60 MPa or less, and more preferably 10 MPa or more and 30 MPa or less. By setting the storage elastic modulus E ′ within the above numerical range, the release layer can have sufficient flexibility. As a result, the followability to the unevenness of the paper becomes good, and the fixing unevenness can be further improved. Such physical properties can be achieved by using PFPE as the fluorine-containing polymer compound that interacts with the polymer chain of PFA.

The loss tangent of the release layer and the storage elastic modulus E ′ can be measured using, for example, a dynamic viscoelasticity measuring device (trade name: Rheogel E4000, manufactured by UBM Co., Ltd.).
The measurement can be performed, for example, by the following method.
A measurement sample (thickness 30 to 200 μm, width 5 mm, length 20 mm) having the same composition as the release layer is prepared. A measurement sample is mounted on a tension jig, and a measurement temperature is increased from 30 ° C. to 250 ° C. at a temperature increase rate of 5.0 ° C./min using a sine wave having a distance between chucks of 10 mm, a frequency of 10 Hz, and an amplitude of 0.03 mm. And calculate a value at a temperature of 180 ° C.

  The measurement sample may be prepared by cutting out from a release layer tube, or may be prepared by cutting out the release layer together with the elastic layer from the fixing member and removing the elastic layer. When the elastic layer contains a crosslinked silicone rubber, the elastic layer can be removed using, for example, a resin solubilizer (trade name: esolv series, manufactured by Kaneko Chemical Co., Ltd.).

(Process 4)
The inner surface of the produced release layer tube is pretreated with sodium, excimer laser, ammonia or the like to activate the surface and improve adhesiveness. An adhesive is applied onto the elastic layer, and a release layer tube is coated on the outer surface of the adhesive and laminated. Although the coating method is not particularly limited, a method of coating an adhesive as a lubricant or a method of expanding and coating a release layer tube can be used. After coating, excess adhesive is handled and removed. Furthermore, the fixing member in the present invention can be manufactured by curing and bonding the adhesive by a heating means such as an electric furnace and processing the end portion as necessary.

<PFA>
Examples of PFA include, for example, perfluoromethyl vinyl ether (CF ₂ ═CF—O—CF ₃ ), perfluoroethyl vinyl ether (CF ₂ ═CF—O—CF ₂ CF ₃ ), and perfluoropropyl vinyl ether (CF ₂ ═ at least a one selected from _{CF-O-CF 2 CF 2} CF 3), a copolymer of tetrafluoroethylene and the like.
The content ratio of PAVE in PFA is preferably 1 mol% or more and 5 mol% or less in the molecular chain, and particularly preferably 3 mol% or more and 5 mol% or less. By setting the content ratio of PAVE in PFA in such a range, the resin viscosity at the time of melt kneading with the fluorine-containing polymer compound can be lowered, and the interaction with the fluorine-containing polymer compound can be further enhanced. Can be increased.

  The melt flow rate (MFR) of PFA is as follows. From the viewpoint of controllability of the molecular motion of the fluorine-containing polymer compound in the release layer and from the viewpoint of enhancing the interaction with the fluorine-containing polymer compound during melt kneading. It is preferably 0 g / 10 min to 10.0 g / 10 min, particularly 1.5 g / 10 min to 3.0 g / 10 min. The MFR of PFA is a value measured using a standard die under the condition of a temperature of 372 ° C. and a load of 5 kgf according to JIS K 7210-1: 2014 A method.

A commercially available product can be used as the PFA, and specific examples are given below.
・ "451HP-J""959HP-Plus""350-J""950HP-Plus" (all trade names, manufactured by Mitsui & DuPont Fluorochemicals)
・ "P-66P", "P-66PT", "P-802UP" (all trade names, manufactured by AGC)
・ "AP-230", "AP-231SH", etc. (both are trade names, manufactured by Daikin)
・ 6505N (trade name, manufactured by 3M)

<PFPE>
Examples of the fluorine-containing polymer compound include perfluoropolyether (PFPE).
Specifically, PFPE which has a structure shown by following Structural formula (1) is mentioned, for example. Among such PFPEs, PFPE that is oily at the melting point of PFA is particularly preferably used.

構造式（１）中、ａ、ｂ、ｃ、ｄ、ｅ、及びｆは、それぞれ独立に０又は正の整数であり、１≦ａ＋ｂ＋ｃ＋ｄ＋ｅ＋ｆ≦６００を満たし、ａ、ｂ、ｃ、及びｄの少なくとも１つは正の整数である。
また、構造式（１）中の各繰り返し単位の存在順序は、構造式（１）における記載の順序に限定されるものではない。さらに、各繰り返し単位は、構造式（１）で表されるＰＦＰＥ中の複数個所に存在しても良い。すなわち、構造式（１）で表されるＰＦＰＥはブロックコポリマーであってもよく、ランダムコポリマーであってもよい。

In Structural Formula (1), a, b, c, d, e, and f are each independently 0 or a positive integer, satisfy 1 ≦ a + b + c + d + e + f ≦ 600, and at least of a, b, c, and d One is a positive integer.
Further, the order of existence of each repeating unit in the structural formula (1) is not limited to the order described in the structural formula (1). Furthermore, each repeating unit may be present at a plurality of locations in the PFPE represented by the structural formula (1). That is, the PFPE represented by the structural formula (1) may be a block copolymer or a random copolymer.

  The molecular weight of PFPE is 5,000 or more, particularly 7,000 or more, as the number average molecular weight, from the viewpoint of better interacting with the polymer chain of PFA and suppressing the molecular mobility of the polymer chain of PFA. Preferably, it is 100,000 or less, and particularly preferably 30,000 or less. Further, PFPE having the above molecular weight has high heat resistance, and even when heated in air at 350 ° C. for 30 minutes, the weight loss is less than 1%, and the thermal decomposition during melt-kneading is extremely small.

  When PFPE is used as the fluorine-containing polymer compound, the content of PFPE in the release layer is 1% by mass or more and 40% by mass or less, particularly 5% by mass or more with respect to the total amount of PFA and PFPE. 30 mass% or less is preferable. By setting the content of PFPE within the above range, the loss tangent of the release layer can be easily adjusted within the above numerical range.

構造式（２）中、ｎは、１以上の整数を表す。
・構造式（３）で表される構造を有するＰＦＰＥ（例えば、「Ｋｒｙｔｏｘ ＧＰＬ１０７」、「Ｋｒｙｔｏｘ ＧＰＬ１０６」（いずれも商品名；ケマーズ社製））：

構造式（３）中、ｎは、１以上の整数を表す。
・構造式（４）で表されるＰＦＡ（例えば、「Ｆｏｍｂｌｉｎ Ｍ６０」、「Ｆｏｍｂｌｉｎ Ｍ３０」（いずれも商品名、ソルベイ社製））：

構造式（４）中、ｎ及びｍはそれぞれ独立に、１以上の整数を表す。 Specific examples of PFPE having a structure included in the structure represented by the general formula (1) are given below.
PFPE having a structure represented by the structural formula (2) (for example, “Demnum S200”, “Demnum S100” (both trade names; manufactured by Daikin)):

In Structural Formula (2), n represents an integer of 1 or more.
PFPE having a structure represented by the structural formula (3) (for example, “Krytox GPL107”, “Krytox GPL106” (both trade names; manufactured by Chemers)):

In Structural Formula (3), n represents an integer of 1 or more.
-PFA represented by structural formula (4) (for example, “Fomblin M60”, “Fomblin M30” (both trade names, manufactured by Solvay)):

In Structural Formula (4), n and m each independently represent an integer of 1 or more.

2. Thermal Fixing Device A thermal fixing device according to an aspect of the present invention includes a heating rotator, and a pressing rotator disposed so as to form a fixing nip portion with the heating rotator. . Examples of the combination of the heating rotator and the pressure rotator include, for example, a heating roller and an elastic pressure roller disposed opposite to the heating roller, and a heating film and the heating film. Examples thereof include an elastic pressure roller, a heating belt, an elastic pressure roller disposed in contact with the heating belt, and a heating belt and a pressure belt disposed in contact with the heating belt.

(1) Fixing Device Using Fixing Belt FIG. 2 is a cross-sectional view in a direction perpendicular to the longitudinal direction of a thermal fixing device including a fixing belt 11 for heating and an elastic pressure roller 19.

  The fixing belt 11 is a fixing belt according to one embodiment of the present invention. The fixing belt 11 is loosely fitted on the belt guide member 16. The pressurizing rigid stay 18 is inserted inside the belt guide member 16. The belt guide member 16 is made of, for example, a resin having heat resistance and heat insulation.

  A ceramic heater 17 serving as a heat source is provided at a position where the belt guide member 16 and the inner surface of the fixing belt 11 are in contact with each other. The ceramic heater 17 is fitted in and fixed to a groove provided along the longitudinal direction of the belt guide member 16. The ceramic heater 17 is energized by means (not shown) to generate heat.

  The elastic pressure roller 19 is provided with an elastic layer 19b containing a cured silicone rubber, for example, on the peripheral surface of a stainless steel core 19a. Moreover, the surface layer 19c containing a fluororesin is provided on the surrounding surface of the elastic layer 19b. The thickness of the surface layer 19c is, for example, 50 μm.

  A pressing force is applied to the pressurizing rigid stay 18 by contracting a pressurizing spring (not shown) between both ends of the pressurizing rigid stay 18 and a spring receiving member (not shown) on the apparatus chassis side. ing. As a result, the lower surface of the ceramic heater 17 disposed on the lower surface of the belt guide member 16 and the upper surface of the elastic pressure roller 19 are pressed against each other with the fixing belt 11 interposed therebetween to form a predetermined fixing nip portion N. That is, the lower surface of the ceramic heater 17 is disposed in contact with the inner peripheral surface of the fixing belt 11.

  The recording medium P, which is an object to be heated, on which an image is formed with the unfixed toner G in the fixing nip portion N is nipped and conveyed at a conveyance speed V. As a result, the toner image is heated and pressurized. As a result, the toner image is melted and mixed, and then cooled to fix the toner image on the recording medium P.

(2) Thermal Fixing Device Using Fixing Roller FIG. 3 shows a fixing roller 12 for heating, an elastic pressure roller 19 disposed opposite to the fixing roller 12, and a heater 20 as a heating means for the fixing roller 12. 2 is a cross-sectional view in a direction orthogonal to the longitudinal direction of a thermal fixing device including

  The fixing roller 12 is a fixing roller according to an aspect of the present invention. In the fixing roller 12, an elastic layer 14 is formed on the outer peripheral surface of the base material 13, and a release layer 15 is formed on the outer side thereof.

  The fixing roller 12 and the elastic pressure roller 19 are pressed against each other by a pressing unit (not shown) to form a fixing nip portion N.

  Inside the fixing roller 12 and the elastic pressure roller 19, a heater 20 is installed as a heat source for supplying heat necessary for melting the unfixed toner G. As the heater 20, a halogen heater is generally used. In some cases, a plurality of halogen heaters are installed inside according to the size of the recording medium P being conveyed.

  A rotation force is applied to the fixing roller 12 and the elastic pressure roller 19 through the end of the base material 13 and the cored bar 19a by means not shown, and the moving speed of the surface of the fixing roller 12 is substantially equal to the conveying speed V of the recording medium P. The rotation is controlled so that the speed is increased. At this time, the rotational force is applied to either the fixing roller 12 or the elastic pressure roller 19 having elasticity, and the other may be rotated by being driven, or the rotational force may be applied to both. .

  The recording medium P to be heated, on which an image is formed with the unfixed toner G, is nipped and conveyed to the fixing nip portion N of the fixing device formed in this way. As a result, the toner image is heated and pressurized. As a result, the toner image is melted and mixed, and then cooled to fix the toner image on the recording medium P.

3. Image Forming Apparatus As the image forming apparatus, there are a multifunction machine using an electrophotographic method, a copy, a fax machine, a printer, and the like. Here, a color laser printer is taken as an example, and the overall configuration of the image forming apparatus will be outlined.

  FIG. 4 is a schematic cross-sectional view of a laser printer 40 according to an embodiment of the present invention. The laser printer 40 shown in FIG. 4 includes an electrophotographic photosensitive drum 39 (hereinafter referred to as “photosensitive member”) that rotates at a constant speed for each color of yellow (Y), magenta (M), cyan (C), and black (K). And an image forming unit having a drum 39 "). The image forming unit further includes an intermediate transfer member 38 that holds the color image that has been developed and transferred in a multiple manner and further transfers the color image to the recording medium P fed from the feeding unit.

  The photosensitive drum 39 (39Y, 39M, 39C, 39K) is rotationally driven counterclockwise as shown in FIG. 4 by driving means (not shown).

  A charging device 21 (21Y, 21M, 21C, 21K) for uniformly charging the surface of the photosensitive drum 39 in order according to the rotation direction, and a laser beam are irradiated on the periphery of the photosensitive drum 39 based on image information. , A scanner unit 22 (22Y, 22M, 22C, 22K) for forming an electrostatic latent image on the photosensitive drum 39, and a developing unit 23 (23Y, 23M, for developing a toner image by attaching toner to the electrostatic latent image. 23C, 23K), a primary transfer roller 24 (24Y, 24M, 24C, 24K) for transferring the toner image on the photosensitive drum 39 to the intermediate transfer member 38 at the primary transfer portion T1, and remains on the surface of the photosensitive drum 39 after transfer. A cleaning unit 25 (25Y, 25M, 25C, 25K) having a cleaning blade for removing residual transfer toner is disposed. .

  When forming an image, a belt-like intermediate transfer member 38 stretched around rollers 26, 27, and 28 rotates and each color toner image formed on each photosensitive drum 39 is superimposed on the intermediate transfer member 38 to be primary. By being transferred, a color image is formed.

  The recording medium P is conveyed to the secondary transfer portion T2 by the conveying means so as to be synchronized with the primary transfer to the intermediate transfer member 38. The conveying means includes a feeding cassette 29 that stores a plurality of recording media P, a feeding roller 30, a separation pad 31, and a registration roller pair 32. At the time of image formation, the feeding roller 30 is driven and rotated in accordance with the image forming operation to separate the recording media P in the feeding cassette 29 one by one, and the registration roller pair 32 performs a secondary operation in synchronization with the image forming operation. It is conveyed to the transfer unit T2.

  A movable secondary transfer roller 33 is disposed in the secondary transfer portion T2. The secondary transfer roller 33 can move substantially in the vertical direction. During image transfer, the secondary transfer roller 33 is pressed against the intermediate transfer member 38 via the recording medium P with a predetermined pressure. At the same time, a bias is applied to the secondary transfer roller 33 and the toner image on the intermediate transfer member 38 is transferred to the recording medium P.

  Since the intermediate transfer member 38 and the secondary transfer roller 33 are respectively driven, the recording medium P sandwiched between the two is transported at a predetermined transport speed V in the left arrow direction shown in FIG. It is conveyed by the belt 34 to the fixing unit 35 which is the next process. In the fixing unit 35, heat and pressure are applied, and the transferred toner image is fixed on the recording medium P. The recording medium P is discharged onto a discharge tray 37 on the upper surface of the apparatus by a discharge roller pair 36.

  The fixing device of the present invention illustrated in FIGS. 2 and 3 is applied to the fixing unit 35 and the secondary transfer roller 33 of the electrophotographic image forming apparatus illustrated in FIG. An image forming apparatus capable of providing a high-quality image can be obtained.

  Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not limited to a following example.

<Preparation of PFA>
PFA listed in Table 1 and PFPE listed in Table 2 were used as raw materials for forming a fluororesin tube for the release layer of the fixing belt according to the example.

Example 1
(Production of release layer)
The ratio of the mass of PFPE to the total mass of PFA and PFPE (hereinafter referred to as “PFPE / (PFA + PFPE)”) of PFA-1 and PFPE-1 containing 1.2 mol% of PAVE in the molecular chain is 0. The mixture was mixed and stirred in a stirrer to obtain a mixture of PFA and PFPE.
The mixture was put into a twin screw extruder and kneaded under the conditions of screw diameter: 46 mm, screw rotation speed: 180 rpm, cylinder temperature: 350 ° C. to 420 ° C. The extruded composition was cooled and cut to prepare PFA / PFPE pellets.

  The prepared PFA / PFPE pellets were put into a single screw extruder having a screw diameter of 40 mm, and the extrusion speed was 50 g / min, the cylinder temperature was 320 ° C. to 370 ° C., and the PFA / PFPE pellets were melted vertically downward. While extruding the tube toward the tube, the tube was pulled at a pulling speed of 3.0 m / min to prepare a fluororesin tube for a release layer having a thickness of 50 μm. The mandrel was adjusted so that the inner diameter of the fluororesin tube was 30 mm.

Measurement sample 1 was collected from the obtained fluororesin tube, and dynamic viscoelasticity (hereinafter referred to as “tan δ1”) at a frequency of 10 Hz and a temperature of 180 ° C. was measured according to the method described above. The storage elastic modulus E ′ was also measured according to the method described above.
Further, a measurement sample 2 was separately collected from the obtained fluororesin tube and heated in an oven at a temperature of 180 ° C. for 200 hours. For the measurement sample 2 after heating, the dynamic viscoelasticity (hereinafter referred to as “tan δ2”) at a frequency of 10 Hz and a temperature of 180 ° C. was measured according to the method described above.

(Preparation of base material and elastic layer)
A base material having an endless belt shape made of nickel electroforming having an inner diameter of 30 mm, a width of 400 mm, and a thickness of 40 μm was prepared as the base material. Primer treatment was applied to the outer peripheral surface of the substrate.

  As a raw material for forming the elastic layer, an addition-curable liquid silicone rubber (trade name: SE1886, manufactured by Toray Dow Corning Co., Ltd.) containing no filler was prepared. With respect to 61 parts by volume of the liquid silicone rubber, 38 parts by volume of spherical alumina (trade name: Aruna Beads CB-A30S, manufactured by Showa Denko KK) is used as a spherical filler, and vapor grown carbon fiber (trade name: trade name: 1 volume part of VGCF-S, manufactured by Showa Denko KK, aspect ratio = 100, average fiber length = 10 μm) was added. Thus, an addition-curable silicone rubber composition for forming an elastic layer was prepared. These are coated on the outer peripheral surface of the base material using a ring coating method, and then heated at a temperature of 200 ° C. for 4 hours to crosslink the layer of the addition-curable silicone rubber composition, resulting in an elastic layer having a thickness of 300 μm. Formed.

While rotating the base material on which the elastic layer is formed at a moving speed of 20 mm / second in the circumferential direction, using an ultraviolet lamp arranged at a distance of 10 mm from the surface of the elastic layer, the surface of the elastic layer is formed. Ultraviolet rays were irradiated in an air atmosphere. As the ultraviolet lamp, a low-pressure mercury ultraviolet lamp (trade name: GLQ500US / 11, manufactured by Toshiba Lighting & Technology Co., Ltd.) was used, and irradiation was performed so that the integrated light amount at a wavelength of 185 nm on the irradiated surface was 800 mJ / cm ² .

(Fixing member production)
Next, an addition curing type silicone rubber adhesive (trade name: SE1819CV, equal amounts of “A liquid” and “B liquid” manufactured by Toray Dow Corning Co., Ltd.) are mixed on the surface of the elastic layer to a thickness of about 20 μm. It applied so that it might become.
Next, as the release layer, cover the fluororesin tube prepared above and handle the belt surface uniformly from above the fluororesin tube, so that excess adhesive can be handled between the elastic layer and the fluororesin tube. I put it out.
An electric furnace set at a temperature of 200 ° C. is charged with an elastic layer and a base material formed by coating the peripheral surface of the elastic layer with a fluororesin tube, heated for 1 hour to cure the adhesive, and the fluororesin tube Was bonded onto the elastic layer, and both ends were cut to obtain a fixing belt having a width of 343 mm. As described later, this fixing belt was evaluated for scratch resistance (Evaluation 1), measurement of the surface free energy of the release layer (Evaluation 2), and evaluation of gloss unevenness in the electrophotographic image (Evaluation 3).

(Examples 2-9)
The fluororesin tubes according to the respective examples were produced in the same manner as the fluororesin tubes according to the example 1 except that the PFA type and the PFPE type used for the production of the fluororesin tube were changed as shown in Table 3 (in addition, the PFA -2 contains 4.3 mol% of PAVE in the molecular chain). For each fluororesin tube, as in Example 1, tan δ1, storage elastic modulus E ′, and tan δ2 were measured.
Further, a fixing belt according to each example was produced in the same manner as in Example 1 except that the fluororesin tube according to each example was used. These fixing belts were subjected to Evaluation 1, Evaluation 2, and Evaluation 3 described later.

(Examples 10 to 13)
Except for changing the mixing ratio (PFPE / (PFA + PFPE)) of PFA and PFPE used for the production of the fluororesin tube as shown in Table 3, each of the examples is the same as the fluororesin tube according to Example 4. A fluororesin tube was prepared. For each fluororesin tube, as in Example 1, tan δ1, storage elastic modulus E ′, and tan δ2 were measured.
Further, a fixing belt according to each example was produced in the same manner as in Example 1 except that the fluororesin tube according to each example was used. These fixing belts were subjected to Evaluation 1, Evaluation 2, and Evaluation 3 described later.

Subsequently, the produced fixing member was evaluated.
<Evaluation 1: Evaluation of scratch resistance>
When the transported paper comes into contact with the fixing member, scratches (paper edge scratches) due to burrs at the edge of the paper are likely to occur, and image defects occur when paper wider than the paper edge scratch occurrence position is used. .
Therefore, the scratch resistance was evaluated by observing the fixed image after continuous paper passage durability. The fixing members produced in the examples and comparative examples are mounted on an electrophotographic image forming apparatus (trade name: imageRUNNER-ADVANCE C5051, manufactured by Canon Inc.), and hammer mill paper (available from International paper, basis weight 75 g / m ² ). 1000 sheets were continuously fed. Thereafter, a fixed image of Bk toner was formed on almost the entire surface of the paper using OK top coat paper (manufactured by Oji Paper Co., Ltd., 157 g / m ² ) which is high gloss paper. This fixed image was used as an evaluation image, and the image level of the letter size paper width was visually observed, and the image influence was evaluated based on the following criteria.
Rank A: Image defects due to scratches on the release layer of the fixing member are not observed.
Rank B: A gloss difference due to scratches on the release layer of the fixing member is recognized.
Rank C: A toner unfixed portion or a remarkable gloss difference is partially recognized due to a scratch on the release layer of the fixing member.

(Evaluation 2: Measurement of surface free energy of release layer)
The surface free energy of the release layer can be calculated by the “Kitazaki / Hatabe method” described in Non-Patent Document 1. That is, first, the contact angle of the release layer of the fixing belt was measured using water, n-hexadecane, and diiodomethane as standard liquids (measuring environment: temperature 23 ° C., relative humidity 55%). Next, using the measurement results of each contact angle, according to the description of “2. Extension of Forks formula” to “3. Surface tension and components of polymer solid” on page 131 of Non-Patent Document 1, “Expanded Fowkes” Surface free energy was calculated from
A contact angle meter (trade name: DM-501, manufactured by Kyowa Interface Science) was used for the measurement, and an analysis software (trade name: FAMAS, manufactured by Kyowa Interface Science) was used for the surface free energy analysis.

(Evaluation 3: Evaluation of gloss unevenness in an electrophotographic image)
The followability of the fixing member to the unevenness present on the rough paper was evaluated by whether or not gloss unevenness was observed in the solid fixing image formed on the rough paper.
The prepared fixing member is mounted on an electrophotographic image forming apparatus (trade name: imageRUNNER-ADVANCE C5051, manufactured by Canon Inc.), and A4 size rough paper (trade name: Business 4200, manufactured by Xerox, thickness 102 μm, basis weight 75 g. / M ² ), a fixed image composed of secondary colors of cyan toner and magenta toner was formed at almost 100% density on almost the entire surface of the paper. This fixed image was used as an evaluation image, visually observed by five subjects, and evaluated based on the following criteria.
Rank A: Four or more people judged that there was little uneven gloss.
Rank B: Three people judged that gloss unevenness was small.
Rank C: Two or less people judged that gloss unevenness was small.

  “Tan δ1”, “tan δ2” and storage elastic modulus E ′ of the fluororesin tubes according to Examples 1 to 13 and “Evaluation 1”, “Evaluation 2” and “Evaluation 3” of the fixing belt according to Examples 1 to 13 The results are shown in Table 4.

(Comparative Example 1)
A fluororesin tube was produced in the same manner as in Example 1 except that PFPE-1 was not used. With respect to this fluororesin tube, tan δ1, storage elastic modulus E ′, and tan δ2 were measured in the same manner as in Example 1.
A fixing belt was produced in the same manner as in Example 1 except that this fluororesin tube was used. This fixing belt was subjected to Evaluation 1, Evaluation 2, and Evaluation 3.

(Comparative Example 2)
A fluororesin tube was produced in the same manner as in Example 4 except that PFPE-1 was not used. With respect to this fluororesin tube, tan δ1, storage elastic modulus E ′, and tan δ2 were measured in the same manner as in Example 1.
A fixing belt was produced in the same manner as in Example 1 except that this fluororesin tube was used. This fixing belt was subjected to Evaluation 1, Evaluation 2, and Evaluation 3.

(Comparative Example 3)
PFA-3 pellets having a PAVE content of 9.8 mol% in the molecular chain were prepared by the method described in JP-A No. 2004-161921. A fluororesin tube was produced in the same manner as the fluororesin tube according to Example 1 except that this pellet was used. With respect to this fluororesin tube, tan δ1, storage elastic modulus E ′, and tan δ2 were measured in the same manner as in Example 1.
A fixing belt was produced in the same manner as in Example 1 except that this fluororesin tube was used. This fixing belt was subjected to Evaluation 1, Evaluation 2, and Evaluation 3.

(Comparative Example 4)
In accordance with the method described in JP-A-2003-82187, a fluororesin pellet in which 5.0% by weight of carbon black was dispersed in PFA-1 was prepared. A fluororesin tube was produced in the same manner as the fluororesin tube according to Example 1 except that this pellet was used. With respect to this fluororesin tube, tan δ1, storage elastic modulus E ′, and tan δ2 were measured in the same manner as in Example 1.
A fixing belt was produced in the same manner as in Example 1 except that this fluororesin tube was used. This fixing belt was subjected to Evaluation 1, Evaluation 2, and Evaluation 3.

“Tan δ1”, “tan δ2” and storage elastic modulus E ′ of the fluororesin tubes according to Comparative Examples 1 to 4, and “Evaluation 1”, “Evaluation 2” and “Evaluation 3” of the fixing belt according to Comparative Examples 1 to 4 The results are shown in Table 4.

  From Table 4, it was found that the fixing member according to this embodiment has excellent toner releasability and excellent scratch resistance, and as a result, a high-quality electrophotographic image can be formed.

DESCRIPTION OF SYMBOLS 11 Fixing belt 12 Fixing roller 13 Base material 14 Elastic layer 15 Release layer 16 Belt guide member 17 Ceramic heater 18 Pressurizing rigid stay 19 Elastic pressure roller 19a Core metal 19b Elastic layer 19c Surface layer 20 Heater 21 Charging device 22 Scanner unit 23 Developing unit 24 Primary transfer roller 25 Cleaning unit 26 Roller 27 Roller 28 Roller 29 Feed cassette 30 Feed roller 31 Separating pad 32 Registration roller pair 33 Secondary transfer roller 34 Conveying belt 35 Fixing section 36 Discharge roller pair 37 Discharge tray 38 Intermediate Transfer body 39 Electrophotographic photosensitive drum (photosensitive drum)
40 Laser printer G Unfixed toner N Fixing nip part P Recording medium V Conveying speed T1 Primary transfer part T2 Secondary transfer part Y Yellow M Magenta C Cyan K Black

Claims (12)

A fixing member having a base material, an elastic layer, and a release layer in this order,
The release layer includes a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer,
A fixing member having a loss tangent of 5.0 × 10 ⁻² or more and 3.0 × 10 ⁻¹ or less at a frequency of 10 Hz and 180 ° C. of the release layer.   The fixing member according to claim 1, wherein the release layer further contains perfluoropolyether. The fixing member according to claim 2, wherein the perfluoropolyether has a structure represented by a structural formula (1).

[In the structural formula (1), a, b, c, d, e, and f are each independently 0 or a positive integer, satisfying 1 ≦ a + b + c + d + e + f ≦ 600, and a, b, c, and d At least one is a positive integer;
The order of existence of each repeating unit in Structural Formula (1) is not limited to the order described in Structural Formula (1), and each repeating unit may be a plurality of repeating units in PFPE represented by Structural Formula (1). It may exist in a place. ] The fixing member according to claim 3, wherein the perfluoropolyether has a structure of any one of structural formulas (2) to (4).

[In Structural Formula (2), n represents an integer of 1 or more. ]

[In Structural Formula (3), n represents an integer of 1 or more. ]

[In Structural Formula (4), n and m each independently represents an integer of 1 or more. ]   The content of the perfluoropolyether is 1% by mass or more and 40% by mass or less based on the total amount of the tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer and the perfluoropolyether. The fixing member according to claim 1.   The fixing member according to claim 1, wherein the release layer has a storage elastic modulus E ′ at a frequency of 10 Hz and 180 ° C. of 5.0 MPa or more and 60 MPa or less. The fixing member according to claim 1, wherein a loss tangent of the release layer at a frequency of 10 Hz and 180 ° C. is 7.0 × 10 ⁻² or more and 3.0 × 10 ⁻¹ or less.   The fixing member according to claim 1, wherein the release layer has a storage elastic modulus E ′ at a frequency of 10 Hz and 180 ° C. of 10 MPa to 30 MPa.   The fixing member according to claim 1, wherein the fixing member is a fixing belt having an endless belt shape.   A fixing device comprising: the fixing member according to claim 1; and a heating unit for the fixing member.   The fixing device according to claim 10, wherein the fixing member is a fixing belt having an endless belt shape, and the heating unit is a heater disposed in contact with an inner peripheral surface of the fixing belt.   An electrophotographic image forming apparatus comprising the fixing device according to claim 10.

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