JP2008039919A - Fixing member, fixing device, image forming apparatus, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing member capable of forming a "silk print" requested, particularly, for photographic picture quality. <P>SOLUTION: A fixing belt 14 is characterized in having a fluorocarbon siloxane rubber layer and a surface layer 141 which sticks on a surface of the fluorocarbon siloxane rubber layer and has fluorocarbon-resin-containing particles partially exposed on the surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing member and the like, and more particularly to a fixing member and the like used in an image forming apparatus.

The toner used in the electrophotographic process is generally produced by a so-called pulverization / classification method. That is, toners are prepared by adding various compounding agents such as a colorant, a charge control agent and a release agent to various resins such as a polyester resin, a styrene-acrylic resin, and an epoxy resin, and melt-kneading to uniformly disperse the compounding agent in the resin. After forming the material, the toner is formed by pulverizing to a predetermined particle size and further removing excess coarse powder and fine powder with a classifier.
In addition, with the recent demand for higher image quality, it has become necessary to reduce the particle size of the toner. As a method for producing a toner having a reduced particle size, an oil phase containing a monomer as a raw material for the above various resins and the above various compounding agents is dispersed in an aqueous phase, and the monomer is dispersed. A method for producing toner particles by polymerization is known. On the other hand, as a resin used for the toner, a material that can be fixed at a lower temperature, that is, a material having a lower glass transition point and a lower softening point is being used because of a demand for energy saving.
Further, as a color toner mounted on a full-color copying machine or a full-color printer, it is desired that multi-color toners are sufficiently mixed in the fixing process (color reproducibility) and excellent in transparency when an OHP image is formed. It is hoped that.

Here, from the viewpoint of sufficiently mixing the multi-colored toner in the fixing step, the resin component contained in the color toner is a low molecular weight resin component that is superior in sharp melt properties compared to the resin component contained in the black toner. Generally used. Then, when color toner is used, there is a problem that an offset is likely to occur.
In addition, in the black toner, a wax having a high crystallinity and a high melting point such as polyethylene and polypropylene is blended from the viewpoint of improving the offset resistance in the fixing process. However, in the color toner for full color, the same wax as that blended in the black toner cannot be blended because the transparency of the OHP image is impaired.

Under such circumstances, in the image forming method using the fixing roll, the surface of the heating roll and / or the pressure roll is formed of silicone rubber or fluororesin excellent in releasability with respect to the toner, and the roll There has been proposed a method for preventing offset by supplying a release liquid such as silicone oil to the surface.
However, when this method is adopted, an apparatus for supplying a releasable liquid is required although it is extremely effective in preventing the toner offset phenomenon. In addition, there is a concern that the output image surface is inferior in writing property, or that sticky paper or adhesive tape is not attached. Furthermore, there is a concern about problems such as an unpleasant odor or contamination in the printing press when the releasable liquid is heated and evaporated.

  Therefore, from the viewpoint of achieving oil-less without impairing the characteristics required for color toners (characteristics such as having low-temperature fixability, sharp melt properties, and small particle size) as much as possible. Color toners containing a melting point wax have been known.

  Further, in the image forming method using a belt-shaped fixing member, a method using a fluorocarbon siloxane rubber excellent in elasticity, heat resistance, releasability from toner, etc. as a surface material of the belt-shaped fixing member (Patent Document 1, 2) was known. In Patent Document 1, after a toner image formed on an electrostatic latent image carrier is transferred onto a recording material, the recording material and a belt-like fixing member formed of fluorocarbon siloxane rubber are overlaid. A method is described in which the toner image is fixed on the recording material by heating and pressing (contact type heating and pressing method).

JP 2004-109687 A Japanese Patent No. 2903972

By the way, in the fixing device employing the contact-type heat and pressure method, the surface property (gloss) of the toner image fixed on the recording material is the toner at the separation point where the toner image is separated from the fixing member along with the recording material. It depends on the temperature and the surface shape of the fixing member.
That is, when the toner temperature is equal to or higher than the melting point of the toner at the peeling point, the gloss of the fixed toner image depends on the viscoelasticity of the toner. On the other hand, when the toner temperature is lower than the melting point of the toner at the peeling point, the surface shape of the fixing member is copied so that the surface of the fixing toner image takes the shape of the surface of the fixing member. In other words, when the toner temperature is lower than the melting point of the toner at the peeling point, if the surface of the fixing member is smooth, the fixed toner image has a very high gloss, that is, a high gloss. On the other hand, the toner (particularly wax component contained in the toner) remains on the surface of the fixing member after many years of use, paper dust adheres, or the surface of the fixing member is modified by the thermal history. In this case, the gloss of the fixed toner image tends to decrease.

Therefore, particularly when the recording material is peeled from the surface of the fixing member at a temperature lower than the melting point of the toner, adjusting the surface state of the fixing member is effective as means for adjusting the gloss of the fixed toner image, and such means is used. For example, it is possible to realize a fixed toner image having a certain uniform gloss.
However, in particular, it has been a very difficult task to realize a matte state called “silk” that is required for photographic quality.

Accordingly, a first object of the present invention is to provide a fixing member capable of forming “silk” particularly required for photographic image quality.
A second object of the present invention is to provide a fixing device capable of forming such “silk”.
Furthermore, a third object of the present invention is to provide an image forming apparatus that realizes an image having such a “silk” state.
A fourth object of the present invention is to provide an image forming method capable of realizing an image having such a “silk” state.

  The inventor has conducted intensive research on a system for fixing using a belt-like fixing member having a surface layer formed of fluorocarbonsiloxane rubber. As a result, it has been found that how to control the roughness of the surface layer of the belt-like fixing member is important in order to stably control the gloss of the image surface. Further, after forming a coating film with the fluorocarbon siloxane rubber precursor composition, before entering the curing step of the coating film, polytetrafluoroethylene (PTFE) fine particles are adhered to the surface, and then the fluorocarbon siloxane rubber precursor composition. It has been found that the above problems can be solved by forming a belt-like fixing member by curing the resin, and the present invention has been achieved.

  That is, the fixing member of the present invention is characterized by having a surface layer comprising a fluorocarbon siloxane rubber layer and fluorine-containing resin particles that adhere to the surface of the fluorocarbon siloxane rubber layer and are partially exposed from the surface. Yes.

  Further, the present invention can be regarded as a fixing device, and the fixing device of the present invention includes a heating member that heats a toner image formed on the surface of a recording material, and a pressure member that is disposed in pressure contact with the heating member. The surface layer of the pressure member includes a fluorocarbon siloxane rubber layer and fluorine-containing resin particles that are attached to the surface of the fluorocarbon siloxane rubber layer and are partially exposed from the surface.

  Furthermore, the present invention can be regarded as an image forming apparatus. The image forming apparatus of the present invention includes an image carrier, a charging unit that charges the surface of the image carrier, and a surface of the image carrier that is charged by the charging unit. An electrostatic latent image forming unit that forms an electrostatic latent image by exposure, a developing unit that develops the electrostatic latent image to form a toner image, a transfer unit that transfers the toner image onto the recording material, and a recording material A fixing unit that heat-fixes the toner image transferred on the recording material, and the fixing unit heats the toner image formed on the surface of the recording material, and the heating member is disposed in pressure contact with the heating member. A pressure member, and the surface layer of the pressure member includes a fluorocarbon siloxane rubber layer and fluorine-containing resin particles that adhere to the surface of the fluorocarbon siloxane rubber layer and are partially exposed from the surface. It is said.

  Further, the present invention can be regarded as an image forming method. The image forming method of the present invention includes a charging step for charging the surface of the image carrier, and exposing the charged surface of the image carrier to form an electrostatic latent image. An electrostatic latent image forming step to be formed; a developing step of developing the electrostatic latent image to form a toner image; a transfer step of transferring the toner image onto a recording material; and a toner image transferred onto the recording material. A fixing step of heating and fixing on the recording material, and the fixing step is performed at a pressure contact portion between a heating member for heating the toner image formed on the surface of the recording material and a pressure member disposed in pressure contact with the heating member. In this process, the surface layer of the pressure member includes a fluorocarbon siloxane rubber layer and fluorine-containing resin particles that are attached to the surface of the fluorocarbon siloxane rubber layer and are partially exposed from the surface. It is characterized by that.

  According to the present invention, it is possible to realize a fixing member having a surface state suitable for forming a matte image called “silk” particularly required for photographic image quality.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to the present embodiment.
A full-color image forming apparatus 1 shown in FIG. 1 includes a fixing device 10 as an example of the present embodiment. The fixing device 10 is heated via an endless fixing belt 14 stretched by three rolls including a heating roll 11, a peeling roll 12, and a walk control roll 13, and an endless fixing belt 14. And a pressure roll 15 that is in pressure contact with the roll 11.
Further, the fixing device 10 includes a cooling heat sink 16 that forcibly cools the fixing belt 14 at a position on the back surface side of the fixing belt 14 and between the heating roll 11 and the peeling roll 12. ing. The surface of the fixing belt 14 is cooled to a range of 50 ° C. to 80 ° C. near the peeling roll 12 by a cooling heat sink 16.
Further, the fixing device 10 is provided with a small-diameter tension roll that applies a certain tension to the fixing belt 14 between the walk control roll 13 and the heating roll 11.
The fixing belt 14 which is a constituent element of the fixing device 10 is an example of the fixing member of the present embodiment. The cooling heat sink 16 can be omitted as appropriate.

The heating roll 11 is provided with an elastic layer. This elastic body layer is a layer made of silicone rubber or the like whose JIS A hardness measured based on JIS K 6253 is usually in the range of A20 to A60. This elastic body layer is provided so as to cover the surface of a metal core made of, for example, aluminum or stainless steel. The thickness of the elastic body layer is usually 1 mm to 3 mm.
Furthermore, the surface of the elastic layer is covered with a release layer made of a PFA tube or the like. The heating roll 11 is formed to have a predetermined outer diameter.
Inside the heating roll 11, a halogen lamp (not shown) is disposed as a heating source. The calorific value of the halogen lamp is usually in the range of 300W to 350W. By this halogen lamp, the surface of the heating roll 11 is heated from the inside so as to have a predetermined temperature (preferably in a range of 130 ° C. to 195 ° C.).

  On the other hand, as the pressure roll 15, for example, one configured similarly to the heating roll 11 is used. That is, as the pressure roll 15, an elastic body layer made of silicone rubber or the like is coated on the surface of a metal core made of aluminum or stainless steel, and a release layer made of a PFA tube or the like is further formed on the surface of the elastic body layer. The one formed to have a predetermined outer diameter is used.

The hardness of the elastic layer provided on the heating roll 11 and / or the elastic layer provided on the pressure roll 15 is usually in the range of A20 to A60 as JIS A hardness measured based on JIS K 6253. . Further, the thickness of the release layer provided on the heating roll 11 and / or the release layer provided on the pressure roll 15 is usually in the range of 1 mm to 3 mm.
Also inside the pressure roll 15, a halogen lamp (not shown) is disposed as a heating source. The calorific value of the halogen lamp is usually in the range of 300W to 350W. By this halogen lamp, the surface of the pressure roll 15 is heated from the inside so as to reach a predetermined temperature (preferably in a range of 85 ° C. to 155 ° C.). In this pressure roll 15, a heating source may be omitted.

  As described above, the fixing belt 14 is stretched around the three rolls including the heating roll 11, the peeling roll 12, and the walk control roll 13 so as to be circulated. The fixing belt 14 circulates clockwise in FIG. 1 at a predetermined moving speed by a heating roll 11 that is rotationally driven by a driving source (not shown). A release agent supply device that supplies a release agent (dimethylsilicone oil) to the surface of the fixing belt 14 may be provided at a position close to the fixing belt 14.

  In addition, the image forming apparatus 1 includes four electrophotographic photosensitive members 21a to 21d (for example, the electrophotographic photosensitive member 21a is yellow, the electrophotographic photosensitive member 21b is magenta, the electrophotographic photosensitive member 21c is cyan, and the electrophotographic photosensitive member. The body 21 d can form an image of a black color), but are arranged in parallel along the intermediate transfer belt 22.

  Each of the electrophotographic photoreceptors 21a to 21d can be rotated in a predetermined direction (counterclockwise in FIG. 1), and the charging rolls 23a to 23d, the developing devices 24a to 24d, and the primary transfer roll along the rotation direction. 25a to 25d and cleaning blades 26a to 26d are arranged. Each of the developing devices 24a to 24d can supply toners of four colors of yellow, magenta, cyan, and black accommodated in the toner cartridges 241a to 241d. The primary transfer rolls 25a to 25d are in contact with the electrophotographic photoreceptors 21a to 21d via the intermediate transfer belt 22, respectively.

  Further, an exposure device 30 is disposed at a predetermined position in the housing, and it becomes possible to irradiate the surfaces of the charged electrophotographic photoreceptors 21a to 21d with laser light emitted from the exposure device 30. Yes. As a result, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photoreceptors 21a to 21d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 22 in an overlapping manner.

  The intermediate transfer belt 22 is supported with a predetermined tension by a drive roll 27, a backup roll 28, and a tension roll 29, and can be rotated without causing deflection due to the rotation of these rolls. The secondary transfer roll 41 is disposed so as to contact the backup roll 28 via the intermediate transfer belt 22. The intermediate transfer belt 22 that has passed between the backup roll 28 and the secondary transfer roll 41 is cleaned by, for example, a cleaning blade disposed in the vicinity of the drive roll 27 and then repeatedly used in the next image forming process. The

  A tray 42 is provided at a predetermined position in the housing. Then, the recording material 43 such as paper in the tray 42 is transferred to the primary fixing device 50 having two rolls in contact with each other between the intermediate transfer belt 22 and the secondary transfer roll 41 by the transfer roll 44. It is transferred sequentially. Further, the recording material 43 is transferred to the secondary fixing device 10 having the fixing belt 14. Thereafter, the recording material 43 is discharged out of the apparatus.

Here, a method for carrying an unfixed toner image on the recording material 43 in the toner image forming section of the image forming apparatus 1 will be described.
In FIG. 1, image signals of four colors of yellow, magenta, cyan, and black are input to the image forming apparatus 1. When these image signals are input, first, in the image forming apparatus 1, the surfaces of the electrophotographic photosensitive members 21a to 21d acting as the photosensitive drums are uniformly charged by the charging rolls 23a to 23d, and then input. Electrostatic latent images are formed on the surfaces of the electrophotographic photoreceptors 21a to 21d by irradiating laser light according to the image information from the exposure device 30 toward the electrophotographic photoreceptors 21a to 21d.
Subsequently, the electrostatic latent images formed on the surfaces of the electrophotographic photoreceptors 21a to 21d are developed with toner in the developing devices 24a to 24d to form toner images on the surfaces of the electrophotographic photoreceptors 21a to 21d. . The toner is toner supplied from the toner cartridges 241a to 241d.
Subsequently, the toner images on the electrophotographic photoreceptors 21 a to 21 d are primarily transferred to the intermediate transfer belt 22 at the respective primary transfer positions. The residual toner is removed from the surfaces of the electrophotographic photoreceptors 21a to 21d after the toner image is primarily transferred to the intermediate transfer belt 22 by the cleaning blades 26a to 26d of the cleaning device. Is removed.

  At the primary transfer position, which is the nip position between the electrophotographic photoreceptors 21a to 21d and the primary transfer rolls 25a to 25d, the primary image is sequentially overlapped with the toner image that has been primarily transferred to the intermediate transfer belt 22 first. Transcript. By doing so, a toner image is formed on the surface of the intermediate transfer belt 22 by superimposing the toner images of the respective colors. Then, the toner images overlapped with each other are secondarily transferred to the recording material 43 at the secondary transfer position sandwiched between the backup roll 28 and the secondary transfer roll 41. In this way, the unfixed toner image is carried on the recording material 43.

  The recording material 43 carrying the unfixed toner image is sent to the first fixing device 50. The fixing device 50 records the unfixed toner image by passing the recording material 43 carrying the unfixed toner image between two rolls in contact with each other to apply heat and pressure to the unfixed toner image. Fix to the material 43.

The recording material 43 on which the toner image is fixed is then sent to the secondary fixing device 10. In the fixing device 10, first, the recording material 43 carrying the primarily fixed toner image is passed through a predetermined nip region (a portion where the heating roll 11 and the pressure roll 15 are in pressure contact), and the fixed toner image is obtained. Then, heat is applied again and pressure is applied to bring the fixing belt 14 into close contact with the image surface.
Next, the recording material 43 is cooled by the cooling heat sink 16, and the temperature of the fixed image surface is lowered.
Then, the recording material 43 is peeled from the fixing belt 14 at the position of the peeling roll 12. Thereafter, the recording material 43 is discharged to a discharge tray provided in the image forming apparatus 1.
In this way, a desired image is formed on the recording material 43.

Next, the fixing belt 14 as an example of the present embodiment will be described in detail. FIG. 2 is a schematic cross-sectional view illustrating various layer configurations of the fixing belt 14.
In FIG. 2A, the fixing belt 14 is formed by laminating the surface layer 141 on the base layer 142.
In FIG. 2B, the fixing belt 14 has a surface layer 141 and a base layer 142 laminated with a silicone rubber layer 143 interposed therebetween. Here, the base layer 142 and the silicone rubber layer 143 are preferably a combination of materials that are easily bonded to each other.
In FIG. 2C, the fixing belt 14 is formed by laminating a surface layer 141 and a base layer 142 via an adhesive layer 144.
In FIG. 2D, the fixing belt 14 is obtained by providing a silicone rubber layer 143 on a base layer 142 via an adhesive layer 144 and further laminating a surface layer 141.

In the present embodiment, the base layer 142 is preferably a sheet or film formed of a material having excellent heat resistance and mechanical strength. More specifically, for example, metal sheets such as nickel, aluminum, and stainless steel, and resin films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide, and polyimide amide can be used.
Here, the volume resistivity of the base layer 142 can be controlled by appropriately adding and dispersing conductive powder or the like in the base layer 142. Examples of such conductive powder include carbon black.
As a method for forming the endless belt-like base layer 142, a known method can be used. More specifically as such a method, for example, a long film or sheet is formed using the above-mentioned material, and both ends thereof are combined in a puzzle shape, and thermocompression-bonded using a thermocompression-bonding member to form an endless belt. The method of tailoring is mentioned.

  The thickness of the base layer 142 is usually 20 μm to 200 μm, preferably 30 μm to 150 μm, more preferably 40 μm to 130 μm. If the thickness of the base layer 142 is excessively small, dimensional stability during heating and cooling and strength may be insufficient. On the other hand, if it is excessively large, the specific heat of the belt-shaped fixing member is increased and the amount of heat transfer is decreased, which may lead to a decrease in transfer speed and cycle time.

  The material of the silicone rubber layer 143 that may be interposed between the base layer 142 and the surface layer 141 is not particularly limited, and examples thereof include dimethyl silicone rubber, methyl vinyl silicone rubber, methyl phenyl silicone rubber, And fluorosilicone rubber. These silicone rubbers may be of the heat vulcanization (HTV) type or of the room temperature curing (RTV) type. The polymerization form may be either an addition type or a condensation type.

  The thickness of the silicone rubber layer 143 is usually 0.1 μm to 1000 μm, preferably 1 μm to 500 μm, more preferably 10 μm to 200 μm. If the thickness of the silicone rubber layer 143 is excessively small, the effect of replacing the base layer 142 may not be expected. On the other hand, if the thickness is excessively large, the specific heat of the belt-like fixing member increases and the amount of heat transfer decreases, and the transfer amount decreases. It may lead to a decrease in speed and cycle time.

In addition, as a material for the adhesive layer 144 that may be interposed between the base layer 142 and the surface layer 141, primers that are usually used for bonding silicone rubber can be applied.
Examples of such primers include aminosilane coupling agents, chlorosilane coupling agents, chloromethylsilane coupling agents, cyanosilane coupling agents, titanate coupling agents, and the like. It is not limited to. Of these, aminosilane coupling agents and titanate coupling agents are preferably used. Furthermore, a primer designed for a fluorocarbon siloxane rubber is also preferably used.

  The thickness of the adhesive layer 144 is generally 0.001 μm to 30 μm, preferably 0.01 μm to 10 μm, more preferably 0.1 μm to 5 μm. If the thickness of the adhesive layer 144 is excessively small, the function as the adhesive layer may not be achieved. On the other hand, if the thickness is excessively large, the adhesive performance may be affected by the strength of the adhesive layer itself.

  In the fixing member of the present embodiment, the surface layer 141 includes a fluorocarbon siloxane rubber layer and fluorine-containing resin particles that adhere to the surface of the fluorocarbon siloxane rubber layer and are partially exposed from the surface. .

  The fluorocarbon siloxane rubber layer is formed by polymerizing a fluorocarbon siloxane rubber precursor composition containing a fluorocarbon siloxane rubber precursor. As a supply form of such a precursor composition, it may be supplied in one liquid type, two liquid type, or other three liquids or more. Further, the polymerization form may be either an addition type or a condensation type.

And as the fluorocarbon siloxane rubber precursor composition,
(A) It is suitable that it is a composition containing each component of a linear fluoropolyether (B) organosilicon compound (C) filler (D) catalyst (E) organosiloxane.

The component (A) preferably has an aliphatic unsaturated group at the molecular chain end and a perfluoroalkyl ether group and / or a perfluoroalkyl group in the main chain. Among these, it is preferable to use a linear fluoropolyether represented by the following general formula (1) or (2).
The aliphatic unsaturated group is not particularly limited, and examples thereof include a monovalent aliphatic unsaturated hydrocarbon group having 2 to 3 carbon atoms. More specifically, alkenyl groups having 2 to 3 carbon atoms such as vinyl group, allyl group and ethynyl group are exemplified, and vinyl group is particularly preferable.

Here, in the general formula (1), R ¹⁰ is an unsubstituted or substituted, preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms or 2 to 2 carbon atoms. 3 alkenyl group, particularly preferably a methyl group. a and e are each 0 or 1, b and d are each an integer of 1 to 4, and c is an integer of 0 to 8. Moreover, x is an integer greater than or equal to 1, Preferably it is 10-30.

Here, in the general formula (2), X represents —CH ₂ —, —CH ₂ O—, —CH ₂ OCH ₂ —, or —Y—NR ¹ —CO— (where Y represents —CH ₂ or a group represented by o, m or p-dimethylsilylphenylene group represented by the following structural formula (Z), R ¹ is a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group.

In the general formula (2), X ′ represents —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ —, or —CO—NR ¹ —Y′— (where Y ′ represents —CH _2- , or o, m or p-dimethylsilylphenylene group represented by the following structural formula (Z ′), and R ¹ is the same group as described above.

Further, in the general formula (2), Rf ¹ is a divalent perfluoropolyether structure represented by the following structural formulas (i) and (ii).

（式中、ｐ及びｑは１〜１５０の整数であって、かつｐとｑの和の平均は、２〜２００である。また、ｒは０〜６の整数、ｔは２又は３である。）

(In the formula, p and q are integers of 1 to 150, and the average of the sum of p and q is 2 to 200. Also, r is an integer of 0 to 6, and t is 2 or 3. .)

（式中、ｕは１〜２００の整数、ｖは１〜５０の整数、ｔは上記と同じである。）

(In the formula, u is an integer of 1 to 200, v is an integer of 1 to 50, and t is the same as above.)

Furthermore, in the general formula (2), g is independently 0 or 1.
In addition, as a compound of the said General formula (1), the compound shown by the following general formula (3) can be mentioned more specifically.

Examples of the component (B) include one or more monovalent perfluorooxyalkyl groups, monovalent perfluoroalkyl groups, divalent perfluorooxyalkylene groups, or divalent perfluoroalkylene groups in one molecule. And an organosilicon compound having two or more hydrogen atoms (SiH groups) bonded to a silicon atom can be used.
(B) As a compounding quantity of a component, it is suitable for content of the said SiH group with respect to the amount of aliphatic unsaturated groups in a fluorocarbon siloxane rubber precursor composition to become 1 time mole amount-4 times mole amount. is there.

  In addition, as such (B) component, the various organohydrogenpolysiloxane used for an addition-curable silicone rubber composition can be used.

  As said (C) component, the various fillers currently used for the general silicone rubber composition can be used. More specifically, for example, reinforcing filler such as aluminum oxide, quartz powder, talc, sericite, bentonite, fumed silica, precipitated silica, carbon powder, titanium dioxide, asbestos, glass fiber, organic fiber, etc. Examples of the fibrous filler can be exemplified.

  As a compounding quantity of the said (C) component, it is 0.1-300 parts normally with respect to 100 parts of (A) component (mass part, hereafter the same), Preferably it is 1-200 parts. If the blending amount of the filler is excessively small, a sufficient reinforcing effect may not be obtained. On the other hand, if it is excessively large, there is a risk that the mechanical strength of the cured product is lowered.

  Examples of the component (D) include chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid and olefin, platinum black or palladium, which are known as addition reaction catalysts, on carriers such as alumina, silica, and carbon. Examples include supported elements, rhodium and olefin complexes, chlorotris (triphenylphosphine) rhodium (Wilkinson catalyst), rhodium (III) acetylacetonate, etc. Group VIII elements or compounds thereof . These compounds are preferably used by dissolving in a solvent such as alcohol, ether, or hydrocarbon.

  Here, the compounding amount (mass) of the catalyst may be an effective amount of the catalyst, but is usually 1 ppm to 500 ppm, preferably 5 ppm to 20 ppm in terms of platinum group metal, relative to 100 parts of component (A). .

  As the component (E), a known organosiloxane can be used. As such an organosiloxane, for example, it is preferable that the siloxane unit further has one or more perfluoroalkyl groups or perfluorooxyalkyl groups bonded to a silicon atom via a carbon atom.

  Various compounding agents can be further added to the fluorocarbon siloxane rubber precursor composition. Examples of such a compounding agent include dispersants such as diphenylsilane diol, low-polymerization degree molecular chain terminal hydroxyl-blocked dimethylpolysiloxane, hexamethyldisilazane; ferrous oxide, ferric oxide, cerium oxide, octyl Examples thereof include heat resistance improvers such as iron acid; colorants such as pigments.

  On the other hand, the fluorine-containing resin particles in the present embodiment are not particularly limited. For example, tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-6 Examples thereof include resin fine particles made of a propylene fluoride copolymer resin as a raw material. Among these, a low molecular weight tetrafluoroethylene resin is preferably applied. In addition, the molecular weight of the tetrafluoroethylene polymer constituting the low molecular weight tetrafluoroethylene resin is usually several thousands to several hundred thousand as the number average molecular weight by F-NMR.

  In addition, the particle diameter of the tetrafluoroethylene resin fine particles is usually 0.01 μm to 5 μm, preferably 0.05 μm to 3 μm, and more preferably 0.8 μm as an average particle diameter measured by an image obtained from an electron microscope. 1 μm to 1 μm. If the particle size is excessively large, surface defects may occur easily. On the other hand, if the particle size is excessively small, the intended effect may not be obtained.

  As such tetrafluoroethylene resin fine particles, those that have been used as additives for reducing the friction coefficient and improving the wear resistance of rubber, plastic, oil, ink, paint, etc. can be used. Examples of commercially available products include Lubron L-2, L-5, L-5F (manufactured by Daikin Industries, Ltd.), MP-1100, MP-1200, MP-1300, MP-1400, MP-1500, TLP-10F. (Both are Mitsui and DuPont Fluorochemical Co., Ltd.).

In the present embodiment, the surface layer 141 includes a fluorocarbon siloxane rubber layer and fluorine-containing resin particles that adhere to the surface of the fluorocarbon siloxane rubber layer.
Here, conventionally, fluorine-containing resin particles typified by tetrafluoroethylene resin fine particles have been publicly known, but it is an active matter for those skilled in the art to attach such fluorine-containing resin particles to the surface of the rubber layer. There was an effective obstruction factor. That is, since both are unfamiliar, it is not considered to use the fluorine-containing resin particles attached to the surface of the fluorocarbon siloxane rubber layer. Conventionally, the fluorine-containing resin particles should be added to the rubber layer. Therefore, it was used to improve the function of the rubber layer itself. In Japanese Patent Laid-Open No. 6-3996, as shown in FIG. 1, it has been known that the silicone fine particles are attached to the surface of the fixing roll / pressure roll in order to prevent the offset. In consideration of supplying silicone oil to the roll surface, silicone fine particles with excellent compatibility with silicone oil have been adopted. There wasn't. In the present embodiment, in the manufacturing process, the fluorocarbon resin rubber layer, which is unfamiliar with the surface of the fluorocarbon siloxane rubber layer, is attached to the surface, so that in fact, the fluorocarbon siloxane rubber layer is completely incorporated into the fluorocarbon siloxane rubber layer. In addition, the surface where the fluororesin fine particles are exposed from the surface, the one that is only in contact with the surface, or the one that is in contact only with the fluororesin fine particles is mixed and formed, and finally It is possible to incorporate the physical properties of the fluorine-containing resin fine particles into the surface.

  In the present embodiment, the amount of the fluorine-containing resin particles attached to the surface of the fluorocarbon siloxane rubber layer is a fluorine-containing amount that occupies the area of the surface layer 141 in a plan view when the surface of the surface layer 141 is viewed vertically from above. The ratio of the area occupied by the resin particles in plan view is usually 1% to 100%, preferably 10% to 100%, and more preferably 50% to 100%. When the ratio is small, the ratio of the fluorine-containing resin fine particles to the surface becomes non-uniform, and the intended effect may not be obtained.

Further, in the surface layer 141 in the present embodiment, at least a part of the surface of the fluorine-containing resin particles adhering to the surface of the fluorocarbon siloxane rubber layer may be exposed from the fluorocarbon siloxane rubber layer. . Therefore, moderate irregularities are given to the surface of the surface layer 141 by the fluorine-containing resin particles.
Here, the average surface roughness (Ra) of the surface layer 141 is usually 0.01 μm to 5 μm, preferably 0.05 μm to 2 μm. If the Ra value is excessively large, image quality may be generated. On the other hand, if the Ra value is excessively small, the intended effect may not be obtained.
In addition, in this Embodiment, an average surface roughness (Ra) value means the arithmetic mean roughness referred to in JIS B 0601-1994, and is a reference length using Surfcom 1400 (measurement instrument made by Tokyo Seimitsu Co., Ltd.). This is a value measured at 4.0 mm and a feed rate of 0.3 mm / s.

In the present embodiment, as a manufacturing method when the fixing belt 14 is manufactured in the mode shown in FIG. 2A, for example, a manufacturing method including the following steps (I) to (III) may be mentioned. it can.
(I) A coating process in which a fluorocarbon siloxane rubber precursor composition is applied to the outer surface of a heat resistant resin or metal tubular belt body (base layer 142).
(II) Fluorine-containing resin particles to which fluorine-containing resin particles are attached to the surface after the coating step and before the fluorocarbon siloxane rubber precursor composition coating film coated on the outer surface of the base layer 142 is cured Adhesion process.
(III) A surface layer forming step of forming the surface layer 141 by curing the fluorocarbon siloxane rubber precursor composition after the fluororesin particle adhesion step.

  In the step (I), as a method of applying the fluorocarbon siloxane rubber precursor composition to the outer surface of the base layer 142, for example, a blade coating method, a wire-bar coating method, a ring coating method, a spray coating method, Known methods such as a dip coating method, a flow coating method, a bead coating method, an air knife coating method, and a curtain coating method can be used. When performing application | coating several times, it is also possible to use multiple types of coating methods together. Among these, use of the dip coating method is advantageous and particularly preferable in terms of seamless coating of the surface layer, mass productivity, cost, film thickness uniformity, and the like.

  Here, the coating solution containing the fluorocarbon siloxane rubber precursor composition is preferably adjusted to a solution viscosity suitable for the coating method to be employed, and m-xylene hexafluoride as necessary. , Perfluoroalkane, perfluoro (2-butyltetrahydrofuran), benzotrifluoride and other solvents.

In the step (II), examples of the method of attaching the fluorine-containing resin particles to the outer surface of the base layer 142 include the following (P) method, (Q) method, and (R) method.
(P) After a pressurized air is blown into the fluorine-containing resin particles in a sealed space to prepare a space called “cloud” in which fine particles have risen, the base layer 142 is introduced into the space, and a certain time has elapsed. How to take out later.
(Q) A method of spraying fluorine-containing resin particles toward the base layer 142 by dry spray coating.
(R) A method in which vibration is applied to a sieve on which fluorine-containing resin fine particles are placed in a sealed space, and the fluorine-containing resin particles are uniformly dropped and adhered toward the base layer 142.

  In the step (III), the curing conditions of the fluorocarbon siloxane rubber precursor composition are exemplified. The curing temperature is usually 50 ° C to 250 ° C, preferably 90 ° C to 200 ° C. In addition, about hardening time, time for hardening reaction to fully advance is set suitably.

  The thickness of the surface layer 141 (total thickness in the case of a plurality of layers) is usually 300 μm or less, preferably 1 to 300 μm, more preferably 5 to 200 μm, and still more preferably 10 to 100 μm. If the thickness is excessively small, the elasticity is insufficient and the effect of adding a rubber layer is lost, which may cause a problem in fixability or insufficient durability. On the other hand, if it is excessively large, the specific heat of the belt-shaped fixing member is increased and the amount of heat transfer is decreased, which may lead to a decrease in transfer speed and cycle time.

  The hardness of the surface layer 141 (JIS A hardness measured by JIS K 6253 “Testing method for hardness of added rubber and thermoplastic rubber”) is usually A5 to A80, preferably A10 to A70, more preferably A20 to A60. It is. If the hardness is excessively small, the strength may decrease and there may be a problem with durability. On the other hand, if it is excessively large, the rigidity increases regardless of the film thickness of the surface layer, the adhesion between the fixing belt 14 and the recording material 43 decreases, and peeling occurs when the cooling is incomplete. Problems that manifest themselves as defects may occur.

The image forming method in the present embodiment includes a charging step for charging the surface of the image carrier, an electrostatic latent image forming step for exposing the charged image carrier surface to form an electrostatic latent image, and an electrostatic latent image. And developing a toner image to form a toner image, a transfer step for transferring the toner image onto the recording material, and a fixing step for heating and fixing the toner image transferred onto the recording material onto the recording material. is there.
The fixing step is a step of passing the recording material through a pressure contact portion between a heating member that heats the toner image formed on the surface of the recording material and a pressure member that is disposed in pressure contact with the heating member.
The surface layer of the pressure member includes a fluorocarbon siloxane rubber layer and fluorine-containing resin particles attached to the surface of the fluorocarbon siloxane rubber layer, and at least a part of the surface of the fluorine-containing resin particles is a fluorocarbon siloxane rubber layer. It is characterized by being exposed from.

Here, the fixing step may be any of the following steps.
(S) A step of fixing the toner image to the recording material by transferring the toner image to the recording material and then applying heat and pressure while the recording material and the belt-like fixing member are overlapped.
(T) After the toner image is transferred to the recording material, the recording material and the belt-shaped fixing member are heated and pressed in a state of being overlapped, and further, after cooling, the recording material is peeled off from the belt-shaped fixing member. The process of fixing to a recording material.

  Further, as the surface layer, after applying the fluorocarbon siloxane rubber precursor composition, before entering the curing step of the fluorocarbon siloxane rubber precursor, the fluororesin particles are adhered to the surface, and then the fluorocarbon siloxane rubber precursor is used. A surface layer obtained by curing the composition is preferred.

When the toner contains a wax, generally, the wax is melted earlier than the binder resin of the toner by heating, and often adheres to the surface of the fixing belt. At this time, if the wax adheres to the surface of the fixing belt with good wettability, the wax is hardly peeled off from the surface of the fixing belt and remains. Such wax residue may cause problems such as offset.
For this reason, belt-like fixing members using fluorocarbon siloxane rubber have been proposed (Japanese Patent Laid-Open No. 2004-109687, Japanese Patent No. 2903972). When such a belt-like fixing member is used, the wax does not easily adhere to the surface of the fixing member, and problems such as offset are reduced.
However, the gloss of the image surface obtained from such a fixing member is extremely uniform, and it is extremely difficult to obtain a matte state called “silk” which is required especially for photographic image quality.

  Conventionally, in order to improve the surface releasability of the belt-like fixing member, an attempt has been made to form a surface layer of the belt-like fixing member by blending raw materials such as fluororubber with ethylene tetrafluoride resin fine particles. However, depending on the method, the tetrafluoroethylene resin fine particles and the like are not exposed on the surface of the belt-like fixing member, and the tetrafluoroethylene resin is used. In some cases, the effect of blending fine particles may not be sufficiently exhibited. Moreover, about obtaining the frosted state called the above-mentioned "silk", the problem remained in the quantity and particle diameter of the tetrafluoroethylene resin fine particle to mix | blend.

  In contrast, in the present embodiment, the surface layer 141 is composed of fluorocarbon siloxane rubber and fluorine-containing resin particles, and at least a part of the surface of the fluorine-containing resin particles is exposed from the fluorocarbon siloxane rubber layer. It is what. By using the fixing belt 14 provided with such a surface layer 141, wax, paper powder, an external additive of toner and the like hardly remain on the fixing belt 14, and the image surface is referred to as silk. An image having a “matt” state can be realized.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[Examples 1-3, Comparative Examples 1-3]
First, a base film made of polyimide having a circumference of 527.8 mm × width 140 mm × thickness 80 μm as a belt-like substrate, and having a volume resistivity adjusted to Rv = 10 ¹² Ω · cm by adding carbon black Formed.
Next, using the raw materials shown in Tables 1 and 2, the coating liquid containing the fluorocarbon siloxane rubber precursor composition was obtained with the formulation shown in Table 4.
Next, the coating solution was applied onto the base film by a dip coating method to form a coating film, and the fluorine-containing resin particles shown in Table 3 were sprayed on the coating film (by dry air spray method). Equipment used: EP-MG10L manufactured by Anest Iwata Co., Ltd., spray supply air pressure 0.3 Mpa.). The adhesion amount was 10 g / m ² .
Thereafter, primary vulcanization at 120 ° C. for 10 minutes and secondary vulcanization at 200 ° C. for 4 hours were performed to obtain a belt-shaped fixing member having a fluorocarbon siloxane rubber layer having a fluororesin attached as a surface layer. . The thickness of the fluorocarbon siloxane rubber layer was 40 μm.
The obtained belt-like fixing member was mounted on DocuCenter Color f450MP manufactured by Fuji Xerox Co., Ltd. having substantially the same configuration as the image forming apparatus shown in FIG. 1, and a full-color image was formed using four color developers. The evaluation results of the image (image quality) are shown in Table 4.

[Example 4]
After obtaining the coating liquid containing the fluorocarbon siloxane rubber precursor composition, primary vulcanization at 120 ° C. for 10 minutes and secondary vulcanization at 200 ° C. for 4 hours are performed to obtain the fluorocarbon siloxane rubber precursor composition. After curing, a belt-like fixing member was obtained in the same manner as in Example 1 except that the fluorine-containing resin particles coated with the adhesive primer were sprayed and dried.
Thereafter, a full color image was formed in the same manner as in Example 1, and the image (image quality) was evaluated. The results are shown in Table 4.

[Comparative Example 4]
Using the raw materials shown in Tables 1 to 3 and the fluororesin particles, the formulation shown in Table 4 (the blending amount of the fluororesin particles was 5 parts by mass with respect to 100 parts by mass of the component A). A coating solution containing a fluorocarbon siloxane rubber precursor composition and fluorine-containing resin particles was obtained.
Next, the coating solution was applied onto the base film by a dip coating method to form a coating film.
Thereafter, primary vulcanization at 120 ° C. for 10 minutes and secondary vulcanization at 200 ° C. for 4 hours are performed to obtain a belt-shaped fixing member having a fluorocarbon siloxane rubber layer containing fluororesin particles as a surface layer. It was. The thickness of the fluorocarbon siloxane rubber layer was 40 μm.
The obtained belt-like fixing member was mounted on DocuCenter Color f450MP manufactured by Fuji Xerox Co., Ltd. having substantially the same configuration as the image forming apparatus shown in FIG. 1, and a full-color image was formed using four color developers. The image evaluation results are shown in Table 4.

[image quality]
Full color printing was performed and evaluated according to the following criteria.
○: An image having a “matte” state called a silk was obtained on the image surface.
Δ: “Glossy” state was obtained, but an image having silk was not obtained.
X: An image having a “matte” state was not obtained.
[durability]
1000 full-color printings were performed and evaluated according to the following criteria.
○: There was no change in image quality between the first and 1000th sheets.
X: A change in image quality was observed between the first and 1000th sheets.

From the results in Table 4, the following matters can be read.
(A) In Examples 1 to 4 each having a surface layer in which fluorine-containing resin particles are adhered to the surface of a fluorocarbon siloxane rubber, an image having a “matte” state called silk is obtained on the image surface. I was able to.
(B) On the other hand, in Comparative Examples 1 and 2, an image having a uniform gloss on the surface could be obtained, but an image having a “matt” state was not obtained.
(C) In Comparative Example 3, a silicone rubber was used in place of the fluorocarbon siloxane rubber, and the fixing belt was formed by attaching fluorine-containing resin particles to the surface. Such a fixing belt was used. In this case, although an image having a frosted state was obtained, an image having a frosted state called “silk” particularly required for photographic quality was not obtained.
(D) Further, in Comparative Example 4, instead of spraying the fluorine-containing resin particles onto the fluorocarbon siloxane rubber precursor composition coating film, the fixing belt was formed by previously blending the fluorine-containing resin particles at the coating liquid stage. However, when such a fixing belt is used, a “matte” state cannot be obtained.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. 3 is a schematic cross-sectional view illustrating various layer configurations of a fixing belt. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Fixing apparatus, 14 ... Fixing belt, 43 ... Recording material, 141 ... Surface layer

Claims (4)

A fluorocarbon siloxane rubber layer;
A fixing member having a surface layer provided with fluorine-containing resin particles attached to the surface of the fluorocarbon siloxane rubber layer and partially exposed from the surface. A heating member for heating the toner image formed on the surface of the recording material;
A pressure member disposed in pressure contact with the heating member,
The surface layer of the pressure member is
A fluorocarbon siloxane rubber layer;
A fixing device comprising: fluorine-containing resin particles attached to a surface of the fluorocarbon siloxane rubber layer and partially exposed from the surface. An image carrier;
Charging means for charging the surface of the image carrier;
An electrostatic latent image forming means for exposing the surface of the image carrier charged by the charging means to form an electrostatic latent image;
Developing means for developing the electrostatic latent image to form a toner image;
Transfer means for transferring the toner image onto a recording material;
Fixing means for heating and fixing the toner image transferred onto the recording material on the recording material,
The fixing means is
A heating member for heating a toner image formed on the surface of the recording material;
A pressure member disposed in pressure contact with the heating member,
The surface layer of the pressure member is
A fluorocarbon siloxane rubber layer;
An image forming apparatus comprising: fluorine-containing resin particles attached to a surface of the fluorocarbon siloxane rubber layer and partially exposed from the surface. A charging step for charging the surface of the image carrier;
An electrostatic latent image forming step of exposing the charged image carrier surface to form an electrostatic latent image; and
A developing step of developing the electrostatic latent image to form a toner image;
A transfer step of transferring the toner image onto a recording material;
A fixing step of heating and fixing the toner image transferred onto the recording material onto the recording material,
The fixing step is a step of passing the recording material through a pressure contact portion between a heating member that heats the toner image formed on the surface of the recording material and a pressure member that is disposed in pressure contact with the heating member.
The surface layer of the pressure member is
A fluorocarbon siloxane rubber layer;
An image forming method comprising: fluorine-containing resin particles attached to a surface of the fluorocarbon siloxane rubber layer and partially exposed from the surface.

Images