JP2019197145A - Fixing member, method for manufacturing the same, image forming apparatus, and image forming method - Google Patents

Abstract

To provide a fixing member that exerts high separation performance during fixing and prevents the occurrence of image unevenness, even when a paper output speed of an image forming apparatus is increased (an image forming apparatus having a copying speed of 70 cpm or more, that is, of Seg. 5 or more is used).SOLUTION: A fixing member of the present invention is a fixing member used for fixing toner in an electrophotographic image forming apparatus. The fixing member has at least an elastic layer and a mold release layer on a base layer, and the mold release layer contains a composite material in which a siloxane compound having a structure represented by the following general formula (1) and a fluorine resin are mixed. General formula (1) M-Si-O (wherein, M represents an unsubstituted or substituted monovalent hydrocarbon group).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fixing member, a manufacturing method thereof, an image forming apparatus, and an image forming method. More specifically, even when the paper output speed of the image forming apparatus is increased, high fixing separation performance is exhibited and image unevenness is caused. There is no fixing member.

  In an electrophotographic image forming apparatus, it is known that a fixing member such as a fixing belt or a fixing roller described below is used to fix unfixed toner on a recording material. As the image forming apparatus increases in speed (for example, an image forming apparatus having a copying speed of 70 cpm or more, so-called Seg. 5 or more is used), a problem arises that the molten toner adheres to the fixing member and a paper jam occurs. Further, as the demand for production prints increases, high image quality is required, and the amount of toner attached to one fixed image varies greatly. For this reason, it is difficult to uniformly fix the toner, and image unevenness is likely to occur.

  The fixing belt as a fixing member is, for example, a heating body made of a ceramic heater, a pressure roller, and a heat-resistant fixing belt made of polyimide or the like sandwiched between the heating body and the pressure roller. The pressure roller is deformed by the pressure applied between the heating body and the pressure roller, so that a so-called fixing nip portion is formed in the deformed portion.

  The fixing roller has a pair of rollers including a heating roller and a pressure roller in contact with the heating roller. In the fixing member, when the pressure roller is deformed by the pressure applied between the heating roller and the pressure roller, a so-called fixing nip portion is formed in the deformed portion.

  In either case, an elastic layer made of silicone rubber or the like is formed on a base layer such as a belt or a roller, and polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) is formed on the outer surface of the rubber layer. A belt or a pressure roller formed by coating a release layer made of a fluororesin or the like is known.

  So far, as a means for preventing paper jam, Patent Document 1 discloses a technique of using polytetrafluoroethylene (PTFE) for the release layer to improve the ability to release from toner and prevent paper jam. . However, the degree of non-adhesiveness of the fluororesin such as polytetrafluoroethylene has a problem that the molten toner adheres to the fixing member, and further, the slipping property is low and it is difficult to convey the fixed image. .

  In Patent Document 2, a fluorine-silicon composite material is formed by having a silicon functional group in a fluororesin molecule. However, there is a problem that silicon functional groups that are expected to be slippery are not easily exposed on the surface.

  Furthermore, there is a technology that uses fluororubber and silicone rubber to improve the releasability. However, when the rubber is used for the release layer, the hardness of the surface layer is lowered and it is difficult to prevent image unevenness (for example, patents). See references 3 and 4.)

  That is, as the speed of the image forming apparatus is increased, the time until the toner is melted and pressed onto the paper is shortened. Therefore, the molten toner is peeled off from the release layer only by adding the PTFE or PFA to the release layer. Instead, the paper is caught in the fixing device and a paper jam occurs.

  Further, a fixing device made of fluoro rubber or a fixing device made of silicone rubber has a problem that the hardness of the surface layer is lowered, fixing unevenness occurs, and image defects occur.

JP 2003-140494 A Japanese Patent Laying-Open No. 2015-031858 JP 2013-015683 A JP 2006-048028 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and situations, and a solution to the problem is fixing that exhibits high fixing separation performance and does not cause image unevenness even when the paper output speed of the image forming apparatus is increased. Another object is to provide a member and a manufacturing method thereof, and an image forming apparatus and an image forming method using the fixing member.

  In order to solve the above-mentioned problems, the present inventor, in the course of examining the cause of the above-mentioned problems, in a fixing member having at least a base layer and an elastic layer and a release layer, the release layer has a specific siloxane compound and fluorine. It has been found that by containing a resin, a fixing member that exhibits high fixing separation performance and does not cause image unevenness can be obtained even when the paper output speed of the image forming apparatus is increased.

  That is, the said subject which concerns on this invention is solved by the following means.

1. A fixing member used for toner fixing of an electrophotographic image forming apparatus,
The fixing member has an elastic layer and a release layer on at least a base layer;
A fixing member, wherein the release layer contains a composite material in which a siloxane compound having a partial structure represented by the following general formula (1) and a fluororesin are mixed.
General formula (1) M-Si-O
(In the formula, M represents an unsubstituted or substituted monovalent hydrocarbon group.)
2. 2. The fixing member according to claim 1, wherein the release layer contains silicon in the range of 3 to 50 at% on the surface.

  3. 3. The fixing member according to item 1 or 2, wherein the composite volume ratio of the siloxane compound and the fluororesin in the composite material is within a range of 10:90 to 40:60.

  4). The fluororesin contains any of polytetrafluoroethylene, perfluoroalkoxyalkane, perfluoropolyether, fluorinated acrylic, fluorinated ethylene-vinyl ether copolymer and fluorinated ethylene-vinyl ester copolymer. The fixing member according to any one of Items 1 to 3, wherein the fixing member is characterized.

  5. The fixing member according to any one of Items 1 to 4, wherein M is a methyl group in the structure represented by the general formula (1).

6). In the siloxane compound and fluororesin contained in the composite material,
The fixing member according to any one of Items 1 to 5, wherein the following relational expression (1) is satisfied.

Relational expression (1): (Molecular weight Mw of siloxane compound) <(Weight average molecular weight Mw of fluororesin)
7. A manufacturing method of a fixing member for manufacturing the fixing member according to any one of items 1 to 6,
A step of adding a siloxane compound satisfying the following relational expression (1) and a fluororesin to a solvent and mixing the mixture with a mixer to obtain a mixture;
Applying the mixture onto an elastic layer made of silicone rubber, and thermally curing the applied mixture to form a release layer made of a composite material of the siloxane compound and fluororesin;
A method for manufacturing a fixing member, comprising:

Relational expression (1): (Molecular weight Mw of siloxane compound) <(Weight average molecular weight Mw of fluororesin)
8). An image forming apparatus comprising the fixing member according to any one of Items 1 to 6.

  9. An image forming method using the fixing member according to any one of items 1 to 6.

  By the above-described means of the present invention, a fixing member that exhibits high fixing separation performance and does not cause image unevenness even when the paper output speed of the image forming apparatus is increased, a manufacturing method thereof, and image formation using the fixing member An apparatus and an image forming method can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The fixing member of the present invention is a fixing member used for toner fixing of an electrophotographic image forming apparatus, and the fixing member has an elastic layer and a release layer on at least a base layer, and the release layer includes the release layer It contains a composite material in which a siloxane compound having a structure represented by the general formula (1) and a fluororesin are mixed.
By mixing two materials, a siloxane compound having a relatively low molecular weight and a fluororesin, the siloxane compound having a low molecular weight passes through the fluororesin as the solvent evaporates and floats on the surface when the release layer is manufactured. It becomes a composite material in which silicon is oriented.

  That is, when a release layer composition according to the present invention is formed by casting a release layer composition on an elastic layer, a siloxane compound having a low molecular weight is formed on the air interface side (release layer surface) along with volatilization of the solvent. Side) with the solvent. After that, in the process where the solvent is dried and volatilized, a concentration gradient is formed in the release layer due to solidification of the fluororesin accompanying drying while a large amount of siloxane compound moves to the air interface side, and silicon is oriented on the surface. It becomes a new composite material. As described above, since the silicon derived from the siloxane compound is unevenly distributed on the surface of the release layer, the surface slipperiness is increased, the molten toner is easily peeled off from the belt surface, and the fixing separation performance can be improved. It is guessed.

  In order to improve the fixing separation property, it is necessary to make the molten toner easily peel from the fixing member (improve the peeling property). The composite material obtained by mixing the siloxane compound and the fluororesin of the present invention has a slipperiness superior to that of a release layer composed of a conventional fluororesin, and is more molten than a release layer composed of a siloxane compound. Since the toner has excellent non-adhesiveness, releasability is improved. Due to the above-described effect, it is possible to improve the fixing separation property.

  Further, unlike the fluoro rubber and silicone rubber conventionally used as the fixing member, the hardness of the surface of the fixing member can be increased by using the composite material. As a result, it is assumed that the molten toner can be fixed uniformly and image unevenness can be eliminated.

  According to the study by the present inventor, a method for increasing the hardness of the surface layer of the fixing member is effective as a method for enhancing the function of reducing image unevenness. Since the fixing member of the present invention can increase the hardness of the surface layer because silicon is oriented on the surface layer, the toner can be crushed irrespective of the difference in the amount of toner adhering to the unfixed image, and image unevenness can be prevented. It is assumed that it can be prevented.

Sectional view showing an example of fixing belt The figure which shows the internal structure of the image forming apparatus main body

  The fixing member of the present invention is a fixing member used for toner fixing of an electrophotographic image forming apparatus, and the fixing member has an elastic layer and a release layer on at least a base layer, and the release layer includes the release layer It contains a composite material in which a siloxane compound having a partial structure represented by the general formula (1) and a fluororesin are mixed. This feature is a technical feature common to or corresponding to the embodiments described below.

  As an embodiment of the present invention, from the viewpoint of manifesting the effect of the present invention, the release layer contains silicon within a range of 3 to 50 at% on the surface, thereby improving the slipperiness of the release layer. From the viewpoint of increasing the surface hardness, it is preferable. More preferably, it is in the range of 3 to 20 at%.

  In addition, the compounding volume ratio of the siloxane compound and the fluororesin in the composite material is in the range of 10:90 to 40:60, so that silicon is easily oriented on the surface when the release layer is produced, and the release layer slips. From the viewpoint of improving the properties and increasing the surface hardness, it is preferable.

  The fluororesin may contain any of polytetrafluoroethylene, perfluoroalkoxyalkane, perfluoropolyether, fluorinated acrylic, fluorinated ethylene-vinyl ether copolymer and fluorinated ethylene-vinyl ester copolymer. In combination with the siloxane compound, it is preferable from the viewpoint of further improving the slipperiness of the release layer and increasing the surface hardness.

  Among them, it is preferable that M of the siloxane compound having a structure represented by the general formula (1) is a methyl group, and in the siloxane compound and the fluororesin, satisfying the relational expression (1) relating to the molecular weight, From the viewpoint of easily orienting silicon on the surface during production of the release layer, improving the slipperiness of the release layer, and increasing the surface hardness.

  The method for producing a fixing member of the present invention includes a step of adding a siloxane compound satisfying the relational expression (1) and a fluororesin to a solvent and mixing with a mixer to obtain a mixture, and applying the mixture onto an elastic layer made of silicone rubber. And a step of thermosetting the applied mixture by heating to form a release layer made of a composite material.

  The image forming apparatus and the image forming method of the present invention use the fixing member of the present invention, so that even if the paper output speed of the image forming apparatus is increased, it exhibits high fixing separation performance and does not cause image unevenness. Is expressed.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< Outline of Fixing Member of the Present Invention >>
The fixing member of the present invention is a fixing member used for toner fixing of an electrophotographic image forming apparatus, and the fixing member has an elastic layer and a release layer on at least a base layer, and the release layer includes: A composite material in which a siloxane compound having a partial structure represented by the general formula (1) and a fluororesin are mixed is included. With this configuration, even if the paper output speed of the image forming apparatus is increased, A fixing member (fixing belt) that exhibits high fixing separation performance and does not cause image unevenness can be provided.
General formula (1) M-Si-O
(In the formula, M represents an unsubstituted or substituted monovalent hydrocarbon group.)
Here, the difference between the fluororubber and the fluororesin according to the present invention will be explained. The “fluororubber” is a polymer obtained by adding a crosslinking agent, a crosslinking aid, a vulcanization accelerator, etc. to a partially fluorinated hydrocarbon polymer. An elastic body having a three-dimensional network structure formed by cross-linking each other. On the other hand, “fluororesin” refers to a partially fluorinated hydrocarbon polymer, and the polymers may not be crosslinked.

  A composite material refers to a material form in which a plurality of components are mixed and dispersed. The two composite materials to be mixed shall not crosslink or polymerize with each other. However, it is included in the scope of the present invention to partially crosslink or partially polymerize within the range that does not impair the effects of the present invention.

  The molecular weight of the siloxane compound refers to the molecular weight Mw of the siloxane compound at the time of blending.

  The weight average molecular weight of the fluororesin refers to the weight average molecular weight of the fluororesin at the time of blending as described above. The weight average molecular weight Mw can be calculated | required from the molecular weight distribution measured by the gel permeation chromatography (GPC: Gel Permeation Chromatography) as follows.

<GPC measurement method>
Specifically, first, a measurement sample is added to tetrahydrofuran so as to have a concentration of 1 mg / mL, followed by a dispersion treatment at room temperature for 5 minutes using an ultrasonic disperser, and then a membrane filter having a pore size of 0.2 μm. To prepare a sample solution. For example, using GPC apparatus HLC-8120GPC (manufactured by Tosoh Corporation) and a column (“TSKgel guardcolumn SuperHZ-L” and “TSKgel SuperHZM-M” (manufactured by Tosoh Corporation)), while maintaining the column temperature at 40 ° C., the carrier solvent Then, tetrahydrofuran is flowed at a flow rate of 0.2 mL / min. 10 μL of the prepared sample solution is injected into the GPC apparatus together with the carrier solvent, the sample is detected using a refractive index detector (RI detector), and a calibration curve measured using monodisperse polystyrene standard particles is used. Calculate the molecular weight distribution of the sample. The calibration curves have molecular weights of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10, respectively. It is prepared by measuring 10 standard polystyrene particles (manufactured by Pressure Chemical) that are ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ .

  The silicon content on the surface of the release layer according to the present invention indicates an element ratio measured by an X-ray photoelectron spectroscopy analysis method (also referred to as an XPS analysis method).

<XPS analysis method>
The XPS analysis method referred to here is a method of analyzing the constituent elements of the sample and their electronic states by irradiating the sample with X-rays and measuring the energy of the generated photoelectrons.

  The element concentration distribution curve (hereinafter referred to as “depth profile”) in the thickness direction of the release layer according to the present invention shows the element concentration of silicon measured by X-ray photoelectron spectroscopy and a rare gas such as argon (Ar). By using together with ion sputtering, it can be measured by sequentially performing surface composition analysis while exposing the inside from the surface of the release layer.

A distribution curve obtained by such XPS depth profile measurement can be created, for example, with the vertical axis as the atomic concentration ratio (unit: at%) of the element and the horizontal axis as the etching time (sputtering time). In addition, in the element distribution curve with the horizontal axis as the etching time in this way, the etching time generally correlates with the distance from the surface of the release layer in the thickness direction of the release layer in the layer thickness direction, As the “distance from the surface of the release layer in the thickness direction of the release layer”, the distance from the surface of the release layer calculated from the relationship between the etching rate and the etching time employed in the XPS depth profile measurement Can be adopted. Further, as a sputtering method employed for such XPS depth profile measurement, a rare gas ion sputtering method using argon (Ar) as an etching ion species is employed, and the etching rate (etching rate) is 0.05 nm / sec. It is preferable to be (SiO ₂ thermal oxide equivalent value).

Hereinafter, an example of specific conditions of XPS analysis applicable to the composition analysis of the release layer according to the present invention will be shown.
・ Analyzer: QUANTERA SXM manufactured by ULVAC-PHI
・ X-ray source: Monochromatic Al-Kα
・ Sputtering ion: Ar (2 keV)
Depth profile: Measurement is repeated at a predetermined thickness interval with a SiO ₂ equivalent sputtering thickness to obtain a depth profile in the depth direction. The thickness interval was 1 nm (data every 1 nm is obtained in the depth direction).
Quantification: The background was determined by the Shirley method, and quantified using the relative sensitivity coefficient method from the obtained peak area. Data processing uses MultiPak manufactured by ULVAC-PHI.

  From the obtained data, the average composition ratio of silicon up to 5 nm is calculated as the thickness from the surface of the release layer. As for the average composition ratio, 10 samples are measured at random and the average value is used.

[1] Configuration of Fixing Member The configuration of the fixing member of the present invention will be described with reference to FIG. The cross-sectional view of the fixing member shown in FIG. 1 is an example, and the present invention is not limited to this. The fixing member will be described below as a fixing belt, but may be a fixing roller as described later.

  In FIG. 1, a fixing member 10 of the present invention has an elastic layer 2 and a release layer 3 in this order on a base layer 1. This structure is the minimum structure of the fixing member, and each layer may be composed of a plurality of layers. The back surface of the base layer 1, the base layer 1 and the elastic layer 2, the elastic layer and the release layer, and the release layer. Another functional layer may be provided on the surface. Examples of the functional layer include an antistatic layer, a smooth layer, a base layer, and an adhesive layer.

  The fixing belt has an endless belt shape. Here, the “endless belt-like shape” means, for example, a loop-like shape formed conceptually (geometrically) by joining both ends of one long sheet-like material. means. The actual shape of the fixing belt is preferably a seamless belt shape or a cylindrical shape.

[1.1] Base layer As the base layer of the fixing belt, heat-resistant belts and sheets are used, and polyimide, polyamide / polyamideimide or thin-film SUS, thin-film nickel electroforming, etc. can be used. It is preferable to use the polyimide which is. The thickness of the base layer is preferably in the range of 10 to 1000 μm, more preferably in the range of 50 to 500 μm, and still more preferably in the range of 50 to 200 μm.

[1.2] Elastic layer The elastic layer is preferably a layer containing a rubber member made of silicone rubber. The elastic layer is preferably composed of two layers, a solid rubber layer and a sponge rubber layer. For example, the solid rubber layer is preferably in the range of 5 to 10 mm, and more preferably in the range of 7 to 8 mm.

  On the other hand, the sponge rubber layer is a sponge-like soft layer containing an infinite number of microballoons. The thickness of the sponge rubber layer is preferably in the range of 5 to 100 μm, and more preferably in the range of 80 to 90 μm.

  The elastic layer is heat-treated after forming a “silicone rubber precursor” on the base layer before curing the silicone rubber raw material molded with a low molecular weight monomer or the like for the silicone rubber forming the rubber member. It hardens.

  The heat treatment method is not particularly limited, and in general, the silicone rubber precursor stored in the chamber is heated by heating the heating chamber from the outside. The heating method may be a batch method or a continuous method. For example, in the case of a batch type, the precursor of the silicone rubber is allowed to stand in the chamber and may be taken out after heating for a predetermined time. Moreover, if it is a continuous type, it is good also as a method of heating for a predetermined time, moving the inside of the said heating chamber, the base layer which formed the precursor of silicone rubber.

  There is no particular limitation except for the step of heating the silicone rubber precursor for forming the rubber member, and the fixing member can be produced using a known method.

  Hereinafter, a specific example will be described up to a method for forming a silicone rubber precursor to be a rubber member of the fixing member.

  First, a rubber raw material (for example, a two-component room temperature curable silicone rubber (trade name: KE-1602, manufactured by Shin-Etsu Chemical Co., Ltd.)) molded with a low molecular weight monomer or the like is added to a curing agent (for example, CAT- 1602, manufactured by Shin-Etsu Chemical Co., Ltd.) and thoroughly mixed with a stirrer to obtain a first mixture.

  Next, for example, an expanded thermally expandable microcapsule (for example, EXPANSEL 461 which is a microballoon manufactured by Akzo Nobel) is added to the first mixture, mixed with a stirrer, and thermally expanded microcapsules. A second mixture containing capsules is obtained.

  Next, for example, a first mixture (not including thermally expandable microcapsules) is applied onto a heat-resistant belt made of polyimide by a coating machine and heated to complete the curing to form a solid rubber layer.

  Thereafter, a second mixture (including thermally expandable microcapsules) is applied to the solid rubber layer to obtain a silicone rubber precursor.

  Next, the silicone rubber precursor becomes a silicone rubber constituting the rubber member of the fixing member through a process of heating in a heating chamber or the like to form an elastic layer.

  Alternatively, after the entire silicone rubber precursor is uniformly heated and crosslinked, the silicone rubber precursor may be further heated for a predetermined time as aging. By aging in this way, the low molecular weight siloxane remaining in the silicone rubber can be further volatilized. As a result, the amount of low molecular weight compounds remaining in the silicone rubber can be further reduced, and as a result used as a product. This is preferable because the amount of the low molecular weight compound that volatilizes when reduced can be reduced.

[1.3] Release layer The release layer according to the present invention comprises a composite material in which a siloxane compound having a partial structure represented by the following general formula (1) and a fluororesin are mixed. With this configuration, it is possible to provide a fixing member (fixing belt) that exhibits high fixing separation performance and does not cause image unevenness even when the paper output speed of the image forming apparatus is increased.
General formula (1) M-Si-O
(In the formula, M represents an unsubstituted or substituted monovalent hydrocarbon group.)
Here, as the unsubstituted or substituted monovalent hydrocarbon group bonded to the silicon atom represented by M, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group Non-condensed hydrocarbon group such as alkyl group, phenyl group, biphenyl group, terphenyl group and the like; pentarenyl group, indenyl group, naphthyl group, azulenyl group, heptaenyl group, biphenylenyl group, fluorenyl group, acenaphthylenyl group, preadenenyl group, Acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl Aryl groups such as fluoranthenyl group, acephenanthrenyl group, acean trirenyl group, triphenylenyl group, pyrenyl group, chrysenyl group, naphthacenyl group, aralkyl groups such as benzyl group, phenylethyl group, phenylpropyl group, vinyl Alkenyl groups such as a group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and an octenyl group.

  Further, from the viewpoint that silicon is easily oriented on the surface of the release layer, the M is preferably a methyl group in order to further enhance the effect of the present invention.

  As a specific siloxane compound, a compound having a relatively small molecular weight is preferable, and pentamethyldisiloxane, hexamethylcyclotrisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane (molecular weight 162.38). ), 1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl) oxy] trisiloxane (molecular weight 310.69), 1,3-dimethoxy-1,1,3,3-tetra Phenyldisiloxane (molecular weight 442.66) or the like can be preferably used.

  The fluororesin is not particularly limited, but polytetrafluoroethylene, perfluoroalkoxyalkane, perfluoropolyether, fluorinated acrylic, fluorinated ethylene-vinyl ether copolymer and fluorinated ethylene-vinyl ester copolymer It is preferable to use any of the above, and it is particularly preferable to use perfluoropolyether (polyoxypropylene ethyl ether: weight average molecular weight 2700 to 5600) which is a perfluoropolyether.

  The thickness of the release layer is preferably in the range of 5 to 50 μm, more preferably in the range of 10 to 40 μm, and particularly preferably in the range of 15 to 30 μm.

  If the thickness of the release layer is 5 μm or more, the effect of the present invention and the hardness of the release layer itself can be maintained, and if it is 50 μm or less, the elasticity of the elastic layer is not inhibited.

[1.4] Manufacturing method of fixing member In the manufacturing method of the fixing member of the present invention, after forming an elastic layer on the base layer, a siloxane compound and a fluororesin satisfying the following relational expression (1) are added to a solvent, A step of obtaining a mixture by mixing with a mixer (a), a step of applying the mixture onto an elastic layer (b), and thermally curing the applied mixture by heating to form a composite of the siloxane compound and the fluororesin And (c) forming a release layer made of a material.

Relational expression (1): (Molecular weight Mw of siloxane compound) <(Weight average molecular weight Mw of fluororesin)
The molecular weight Mw of the siloxane compound is preferably in the range of 100 to 10,000, more preferably in the range of 100 to 5000, still more preferably in the range of 100 to 3000, and in the range of 100 to 500. In particular, it is particularly preferable from the viewpoint of easy orientation of silicon on the surface of the release layer.

  If the molecular weight Mw of the siloxane compound is in the range of 100 to 10,000, the composite material of the present invention can be formed together with the fluororesin according to the present invention, which is a preferable range.

  The weight average molecular weight Mw of the fluororesin is preferably in the range of 1000 to 100,000, more preferably in the range of 2000 to 50000, and particularly preferably in the range of 5000 to 10,000.

  The weight average molecular weight Mw of the fluororesin is in the range of 1000 to 100,000 and satisfies the above relational expression (1) with the molecular weight of the siloxane compound, thereby forming the composite material of the present invention together with the siloxane compound according to the present invention. This is a preferable range.

  The molecular weight Mw and the weight average molecular weight Mw both refer to the molecular weight at the time of blending.

  Each of the above steps will be described.

  Step (a) is a step in which a siloxane compound and a fluororesin are added to a solvent and mixed with a mixer to obtain a mixture.

  When mixing, it is preferable to adjust each mixing amount so that the compounding volume ratio of the siloxane compound of a final composite material and a fluororesin is in the range of 10:90 to 40:60.

  As an apparatus used for mixing, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

  Step (b) is a step of applying the mixture onto an elastic layer made of silicone rubber.

  Examples of coating methods include spin coating, casting, die coating, blade coating, roll coating, spray coating, curtain coating, etc., but it is easy to obtain a uniform thin film and from the viewpoint of high productivity. A method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, or a spray coating method is preferable.

  Step (c) is a step of thermally curing the applied mixture to form a release layer made of a composite material of the siloxane compound and a fluororesin.

  As a device for heating, it is preferable to use a heating chamber.

  The release layer according to the present invention is characterized by the fact that the siloxane compound having a small molecular weight moves together with the solvent to the air interface side (release layer surface side) as the solvent evaporates by heating in the step (c) and subsequent drying and aging. . After that, in the process where the solvent is dried and volatilized, a concentration gradient is formed in the release layer due to solidification of the fluororesin accompanying drying while a large amount of siloxane compound moves to the air interface side, and silicon is oriented on the surface. It becomes a new composite material. As described above, the silicon derived from the siloxane compound is unevenly distributed on the surface of the release layer, whereby the surface slipperiness is increased, and the molten toner is easily peeled off from the belt surface, so that the fixing separation performance can be improved.

[2] Outline of Image Forming Method The image forming method of the present invention is an image having at least steps of developing an electrostatic latent image with toner to form a toner image, and transferring and fixing the toner image onto a recording medium. A fixing method according to the present invention is characterized in that the fixing member of the present invention (for example, a fixing belt) is used in the fixing step.

[2.1] About each step The above steps include, for example, a charging step, an electrostatic latent image, in addition to a toner image fixing step (hereinafter also simply referred to as “fixing step”) on a recording medium. Steps used in a general electrophotographic image forming method, such as a step of forming, developing, transferring, and cleaning.

  The recording medium is not particularly limited, and a known medium can be used. Specifically, for example, in addition to paper such as plain paper or coated paper, a color attached to the surface such as a cloth or a sheet-like resin. Various media capable of fixing the material are listed.

[Toner image]
A toner image is an image formed by developing an electrostatic latent image with toner.

  In the present invention, the toner image transferred onto the recording medium is preferably a black toner image or a color toner image formed of two or more toners. The variation of the color toner image is not particularly limited. For example, the color toner image may contain at least two toners of cyan, magenta, yellow, and black, or two colors of black and white. The toner image may be a toner image composed of the above toner, or may be a toner image containing other multiple color toners.

  According to the present invention, even the color toner formed with such a black toner image or toners of two or more colors can preferably exhibit the above-described effects.

[toner]
The toner according to the present invention is a toner for developing an electrostatic latent image, and includes at least toner particles.

  In the present invention, “toner” means an aggregate of “toner particles”.

(Toner particles)
The toner particles contain a binder resin including at least a thermoplastic resin in the toner base particles, and optionally contain a release agent.

  Here, the “toner base particle” is a particle containing at least a binder resin and a colorant. The toner base particles can be used as toner particles as they are, but it is usually preferable to use toner particles to which external additives have been added.

  The method for producing the toner base particles is not particularly limited, and examples thereof include known methods such as a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method.

(Coloring agent)
For the toner base particles, a known material can be used as a coloring agent for yellow, magenta, cyan, and black. Moreover, the coloring agent (white) using inorganic particles, such as titanium dioxide, can also be used.

  Specific examples of the colorant are as follows. The following colorants are compounds that absorb light in the wavelength range of 280 to 480 nm.

  Examples of the colorant for obtaining a black toner include carbon black, magnetic material, and iron / titanium composite oxide black. Examples of the carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Can be mentioned. Examples of the magnetic material include ferrite and magnetite.

  Examples of the colorant for obtaining a yellow toner include C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, etc .; C.I. I. Pigment yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, and the like.

  Examples of the colorant for obtaining a magenta toner include C.I. I. Dyes such as Solvent Red 1, 49, 52, 58, 63, 111, 122; I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, and the like.

  Examples of the colorant for obtaining cyan toner include C.I. I. Dyes such as Solvent Blue 25, 36, 60, 70, 93, 95; I. Pigment blue 1, 7, 15, 60, 62, 66, 76, 15: 3 and the like.

  Specific examples of the white colorant include inorganic pigments (for example, heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, titanium white, talc, calcium sulfate, barium sulfate, zinc oxide, and oxidation). Magnesium, magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, smectite, etc.), organic pigments (eg polystyrene resin particles, urea formalin resin) Particles). Moreover, the pigment which has a hollow structure, for example, a hollow resin particle, a hollow silica, etc. are mentioned.

  The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color.

  The content of the colorant is preferably 0.5 to 20% by mass in the toner, and more preferably 2 to 10% by mass.

(Binder resin)
The toner can contain a binder resin. It is generally known that toner particles having a substantially uniform particle diameter and shape can be produced by using an emulsion aggregation method as a toner production method.

  In the toner, a resin generally used as a binder resin constituting the toner can be used as a binder resin as long as the effect of the present invention is not inhibited. Examples of such resins include thermoplastic resins, and specific examples include styrene resins, acrylic resins, styrene / acrylic resins, polyester resins, silicone resins, olefin resins, amide resins, and epoxy resins. These binder resins can be used singly or in combination of two or more.

  Among these, the binder resin is at least one selected from the group consisting of a styrene resin, an acrylic resin, a styrene / acrylic resin, and a polyester resin from the viewpoint of low viscosity when melted and high sharp melt properties. It is preferable that at least 1 sort (s) selected from the group which consists of a styrene acrylic resin and a polyester resin is included.

  The glass transition temperature (Tg) of the binder resin is preferably in the range of 30 to 70 ° C, more preferably in the range of 35 to 60 ° C, from the viewpoints of fixability and heat-resistant storage stability. Tg can be measured by differential scanning calorimetry (DSC).

(Release agent)
The toner may contain a release agent. The release agent to be used is not particularly limited, and various known waxes can be used. Examples of the wax include low molecular weight polypropylene, polyethylene or oxidized low molecular weight polypropylene, polyolefin such as polyethylene, paraffin, synthetic ester wax, and the like, and particularly, use a synthetic ester wax because of its low melting point and low viscosity. It is particularly preferable to use behenyl behenate, glycerin tribehenate, pentaerythritol tetrabehenate or the like as the synthetic ester wax.

  The content of the release agent is preferably in the range of 1 to 30% by mass in the toner, and more preferably in the range of 3 to 15% by mass.

(Charge control agent)
The toner may contain a charge control agent. The charge control agent to be used is not particularly limited as long as it is a substance that can give positive or negative charge by frictional charging and is colorless, and various known positively chargeable charge control agents and negative charge agents can be used. A chargeable charge control agent can be used.

  The content of the charge control agent is preferably in the range of 0.01 to 30% by mass in the toner, and more preferably in the range of 0.1 to 10% by mass.

(External additive)
In order to improve the fluidity, chargeability, cleaning properties, etc. of the toner, the toner may be constituted by adding external additives such as a so-called post-treatment agent such as a fluidizing agent and a cleaning aid to the toner particles. Good.

  Examples of the external additive include inorganic oxide particles such as silica particles, alumina particles, and titanium oxide particles, inorganic stearate compound particles such as aluminum stearate particles and zinc stearate particles, strontium titanate particles, and zinc titanate particles. And inorganic particles such as inorganic titanic acid compound particles. These can be used alone or in combination of two or more.

  The surface of these inorganic particles may be modified with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.

  The addition amount of these external additives is preferably 0.05 to 5% by mass in the toner, and more preferably 0.1 to 3% by mass.

(Toner particle size)
The particle diameter of the toner is preferably 4 to 10 μm, more preferably 4 to 7 μm in terms of volume-based median diameter (D50). When the volume-based median diameter (D50) is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  In the present invention, the volume-based median diameter (D50) of the toner is a computer system (Beckman Co., Ltd.) equipped with data processing software “Software V3.51” in “Coulter Counter 3” (manufactured by Beckman Coulter, Inc.). It is measured and calculated using a measuring apparatus connected to Coulter Co., Ltd.

  Specifically, 0.02 g of a measurement sample (toner) was added to 20 mL of a surfactant solution (for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Solution) and ultrasonically disperse for 1 minute to prepare a toner dispersion. This toner dispersion is placed in “ISOTON II” (manufactured by Beckman Coulter, Inc.) in the sample stand. Pipette into a beaker until the displayed concentration of the measuring device is 8%.

  Here, a reproducible measurement value can be obtained by setting the concentration range. In the measuring apparatus, the number of particles to be measured is 25000, the aperture diameter is 50 μm, the frequency range is calculated by dividing the range of 1 to 30 μm, which is the measurement range, into 256 parts, and the volume integrated fraction is larger. A particle diameter of 50% is defined as a volume-based median diameter (D50).

[Other processes]
Hereinafter, processes used in a general electrophotographic image forming method, such as a charging process, an electrostatic latent image forming process, a developing process, a fixing process, and a cleaning process, will be described.

(Charging process)
In this step, the electrophotographic photosensitive member is charged. The charging method is not particularly limited, and may be a known method such as a charging roller method in which the electrophotographic photosensitive member is charged by a charging roller.

(Process of forming electrostatic latent image)
In this step, an electrostatic latent image is formed on the electrophotographic photosensitive member (electrostatic latent image carrier).

  The electrophotographic photosensitive member is not particularly limited, and examples thereof include a drum-shaped one made of an organic photosensitive member such as polysilane or phthalopolymethine.

  The electrostatic latent image is formed, for example, by uniformly charging the surface of the electrophotographic photosensitive member with a charging unit and exposing the surface of the electrophotographic photosensitive member imagewise with an exposing unit. The electrostatic latent image is an image formed on the surface of the electrophotographic photosensitive member by such charging means.

  The charging means and the exposure means are not particularly limited, and those generally used in electrophotography can be used.

(Developing process)
The developing step is a step of developing the electrostatic latent image with toner (generally, a dry developer containing toner) to form a toner image.

  The toner image is formed, for example, by using a developing unit including a stirrer that frictionally stirs and charges the toner using a dry developer containing toner and a rotatable magnet roller.

  Specifically, in the developing unit, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and is held on the surface of the rotating magnet roller, thereby forming a magnetic brush. Since the magnet roller is disposed in the vicinity of the electrophotographic photosensitive member, a part of the toner constituting the magnetic brush formed on the surface of the magnetic roller moves to the surface of the electrophotographic photosensitive member by an electric attractive force. . As a result, the electrostatic latent image is developed with toner, and a toner image is formed on the surface of the electrophotographic photosensitive member.

(Transfer process)
In this step, the toner image is transferred to a recording medium.

  Transfer of the toner image to the recording medium is performed by peeling and charging the toner image onto the recording medium.

  As the transfer means, for example, a corona transfer device using corona discharge, a transfer belt, a transfer roller, or the like can be used.

  In addition, in the transfer step, for example, an intermediate transfer member is used, a toner image is primarily transferred onto the intermediate transfer member, and then the toner image is secondarily transferred onto a recording medium. It can also be carried out by a mode in which the formed toner image is directly transferred to a recording medium.

(Process of fixing)
In the fixing step according to the present invention, a recording material onto which an unfixed image (toner image) formed using toner is transferred is passed between a heated fixing belt or fixing roller and a pressure member. To fix the unfixed image on the recording material. When the fixing belt or the fixing roller used is the fixing member according to the present invention, the paper output speed of the image forming apparatus is increased (using a copying speed of 70 cpm or more, so-called Seg. 5 or more image forming apparatus). However, it is possible to obtain an effect that exhibits high fixing separation performance and does not cause image unevenness.

  Specifically, for example, the fixing process is performed by a fixing belt or a fixing roller as a fixing rotator, and a pressure belt provided in a state where the fixing belt or the fixing roller is pressed to form a fixing nip portion. Examples thereof include a belt fixing method or a roller fixing method constituted by a pressure roller as a pressure member.

(Process to clean)
In this step, the developer that has not been used for image formation or remains untransferred is removed from the developer carrier such as a photoconductor and an intermediate transfer member.

  The cleaning method is not particularly limited, but it is preferable to use a blade that scrapes the surface of the photoconductor, the tip of which is in contact with the object to be cleaned such as the photoconductor.

[3] Image Forming Apparatus The image forming apparatus of the present invention can use a general image forming apparatus other than the image forming method of the present invention.

  The configuration of the image forming apparatus main body 100 will be described with reference to FIG. FIG. 2 is a diagram illustrating an internal configuration of the image forming apparatus main body 100.

  As shown in FIG. 2, the image forming unit 40 includes image forming units 41Y, 41M, 41C, and 41K that form an image using each color toner of YMCK according to control of an image control CPU (Central Processing Unit) 11 described later. Since these have the same configuration except for the toner to be accommodated, the symbols representing the colors may be omitted hereinafter. The image forming unit 40 further includes an intermediate transfer unit 42 and a secondary transfer unit 43.

  The image forming unit 41 includes an exposure unit 411, a developing unit 412, a photosensitive drum 413, a charging unit 414, and a drum cleaning unit 415. The photoreceptor drum 413 is, for example, a negatively charged organic photoreceptor. The surface of the photosensitive drum 413 has photoconductivity. The charging unit 414 is, for example, a corona charger. The charging unit 414 may be a contact charging device that charges a contact charging member such as a charging roller, a charging brush, or a charging blade by contacting the photosensitive drum 413. The exposure unit 411 includes, for example, an LD (LASER Diode) 411a that outputs laser light as a light source, and a light deflection device (polygon motor) that irradiates the photosensitive drum 413 with laser light corresponding to an image to be formed. Including.

  The developing unit 412 is a two-component developing type developing device. The developing unit 412 includes, for example, a developing container that contains a two-component developer, a developing roller (magnetic roller) that is rotatably disposed in an opening of the developing container, and a developing container that allows the two-component developer to communicate with each other. A partition partitioning the inside, a transport roller for transporting the two-component developer on the opening side of the developing container toward the developing roller, and an agitation roller for stirring the two-component developer in the developing container . The developer container contains the toner as a two-component developer.

  The intermediate transfer unit 42 includes a primary transfer roller 422 that presses the intermediate transfer belt 421 against the photosensitive drum 413, a plurality of support rollers 423 including a secondary transfer roller Up (backup roller) 423A, and a belt cleaning unit 426. The intermediate transfer belt 421 is looped around the plurality of support rollers 423. When at least one drive roller of the plurality of support rollers 423 rotates, the intermediate transfer belt 421 travels at a constant speed in the direction of arrow a.

  The secondary transfer unit 43 includes a plurality of support rollers 431 including an endless secondary transfer belt 432 and a secondary transfer roller Lw (lower side) 431A. The secondary transfer belt 432 is stretched in a loop shape by the secondary transfer roller Lw431A and the support roller 431.

  The fixing unit 60 heats and pressurizes the paper on which the toner image is formed by the image forming unit 40 under the control of the image control CPU 11 described later. The fixing unit 60 includes an endless fixing belt 61 that is a fixing member according to the present invention, a heating roller 62, a fixing roller 63 disposed to face the pressure roller 64, a pressure roller 64, and air separation. Unit 65. The fixing belt 61 is stretched between the heating roller 62 and the fixing roller 63. The heating roller 62 incorporates heating means such as a halogen heater (not shown) for heating the fixing belt 61. The fixing roller 63 forms a nip portion N between the fixing belt 61 and the pressure roller 64.

  In the above configuration, when the pressure roller 64 is rotated counterclockwise by a driving unit (not shown), the fixing belt 61, the heating roller 62, and the fixing roller 63 are rotated and rotated clockwise. The fixing belt 61 is heated by the abutting heating roller 62 and the fixing roller 63 is also heated. Then, the paper on which the toner image is formed is heated and pressurized by passing through the nip portion N, and the toner image transferred onto the paper is melted and fixed.

  The air separation unit 65 separates the paper from the fixing belt 61 by blowing air to the paper discharged from the nip portion N. The air separation unit includes a suction fan (not shown) that sucks air from the outside and sends it in the direction of the nip N, and a duct that is a path of the sent air. By separating the paper from the fixing belt 61 by the air separation unit 65, the paper can be separated without bringing a member such as a separation claw into contact with the surface of the fixing belt 61, so that the surface of the fixing belt 61 is damaged. There is no.

  The image forming apparatus main body 100 further includes a scanner unit 30, a reading processing unit 13, a paper feed unit 50, and a paper transport unit 70. The scanner unit 30 includes a paper feeding device 301 and a scanner 302. The scanner unit 30 feeds a document d by a paper feeding device 301 under the control of an image control CPU 11 described later, and scans the document d by a CCD (Charge Coupled Device) sensor 32 of the scanner 302 to acquire input image data. . The paper feed unit 50 includes paper feed units 50a and 50b. The paper feeding unit 50 feeds the paper S to the image forming unit 40 according to the control of the image control CPU 11 described later. In the three paper feed tray units 51a, 51b, 51c constituting the paper feed unit 50a and the external paper feed unit 50b, a paper S (standard paper, special paper) identified based on basis weight, size, or the like is provided. Accommodated for each preset type.

  The paper transport unit 70 includes a paper discharge unit 72 and a transport path unit 73. The paper transport unit 70 transports the paper S to the image forming unit 40 by the transport path unit 73 and discharges the paper S from the fixing unit 60 by the paper discharge unit 72 according to the image control CPU 11 described later. The conveyance path unit 73 includes a plurality of conveyance roller pairs such as registration roller pairs 73a. The paper transport unit 70 includes a reversing path unit that reverses the paper on which one side has been imaged and transports the paper to the image forming unit 40 again.

  Here, an example of an image forming method by the image forming apparatus main body 100 will be described. The scanner 302 optically scans and reads a document d fed on the contact glass by the paper feeding device 301 or placed on the platen glass. The reflected light from the document d is read by the CCD sensor 32 of the scanner 302 and becomes input image data. The input image data is subjected to predetermined image processing in the reading processing unit 13 and sent to the exposure unit 411.

  The photosensitive drum 413 rotates at a constant peripheral speed. The charging unit 414 uniformly charges the surface of the photosensitive drum 413 to a negative polarity. In the exposure unit 411, the polygon mirror of the polygon motor rotates at high speed, and the laser light corresponding to the input image data of each color component is developed along the axial direction of the photoconductive drum 413, and the photoconductor along the axial direction. The drum 413 is irradiated on the outer peripheral surface. Thus, an electrostatic latent image is formed on the surface of the photosensitive drum 413.

  In the developing unit 412, the toner particles are charged by stirring and transporting the two-component developer in the developing container, and the two-component developer is transported to the developing roller, and forms a magnetic brush on the surface of the developing roller. The charged toner particles are electrostatically attached to the electrostatic latent image portion on the photosensitive drum 413 from the magnetic brush. In this way, the electrostatic latent image on the surface of the photosensitive drum 413 is visualized, and a toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 413.

  The toner image on the surface of the photosensitive drum 413 is transferred to the intermediate transfer belt 421 by the intermediate transfer unit 42. Transfer residual toner remaining on the surface of the photosensitive drum 413 after the transfer is removed by a drum cleaning unit 415 having a drum cleaning blade that is in sliding contact with the surface of the photosensitive drum 413.

  When the intermediate transfer belt 421 is pressed against the photosensitive drum 413 by the primary transfer roller 422, a primary transfer nip is formed for each photosensitive drum by the photosensitive drum 413 and the intermediate transfer belt 421. In the primary transfer nip, the toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 421.

  On the other hand, the secondary transfer roller Lw431A is pressed against the secondary transfer roller Up423A via the intermediate transfer belt 421 and the secondary transfer belt 432. Accordingly, a secondary transfer nip is formed by the intermediate transfer belt 421 and the secondary transfer belt 432. The sheet S passes through the secondary transfer nip. The sheet S is conveyed to the secondary transfer nip by the sheet conveying unit 70. The correction of the inclination of the sheet S and the adjustment of the conveyance timing are performed by a registration roller unit provided with a registration roller pair 73a.

  When the sheet S is conveyed to the secondary transfer nip, a transfer bias is applied to the secondary transfer roller Lw431A. By applying the transfer bias, the toner image carried on the intermediate transfer belt 421 is transferred onto the paper S. The sheet S on which the toner image is transferred is conveyed toward the fixing unit 60 by the secondary transfer belt 432.

  The fixing unit 60 forms a nip portion N by the fixing belt 61 and the pressure roller 64, and heats and presses the conveyed paper S at the nip portion N.

  In the belt heating type fixing device, it is preferable that the temperature of the heating body be relatively low, specifically, 150 ° C. or less. Furthermore, the temperature of the heating body is more preferably 140 ° C. or less, and particularly preferably 135 ° C. or less. The lower limit of the temperature of the heating body is not particularly limited, but is substantially about 90 ° C.

  The toner particles constituting the toner image on the paper S are heated, and the crystalline resin melts quickly inside the toner S. As a result, the entire toner particles are quickly melted with a relatively small amount of heat, and the toner component is transferred to the paper S. Adhere to. Thus, the toner image is quickly fixed on the paper S with a relatively small amount of heat. The sheet S on which the toner image is fixed is discharged to the image reading apparatus 200 by the sheet discharge unit 72 including the sheet discharge roller 72 a of the sheet conveyance unit 70. Thus, a high-quality image is formed.

  Note that the transfer residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer is removed by a belt cleaning unit 426 having a belt cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 421.

  In the above description, the fixing belt is used as an example of the fixing member. However, a fixing roller can be similarly manufactured and used.

  The fixing roller is a rubber roller for fixing toner on paper in an electrophotographic image forming apparatus, and is formed by using an elastic layer made of a silicone rubber composition and a release layer according to the present invention as an outer layer of a core material. It is. Examples of the fixing roller include a cylindrical roller having silicone rubber (hereinafter also simply referred to as a rubber member) as an elastic layer.

  The rubber hardness of the rubber member of the fixing roller is preferably in the range of 30 to 60 °. The rubber hardness can be adjusted by, for example, the heating temperature and heating time in molding or vulcanization.

  The rubber hardness on the shaft is obtained by measuring the surface hardness of the fixing roller according to JIS-S-6050. Specifically, it is measured at a load of 600 g using an ASKER-C type rubber hardness meter manufactured by Kobunshi Keiki Co., Ltd. Further, in order to observe the rubber hardness on the shaft, the measurement is performed using a positioning member in which the roller circumferential direction vertical portion is positioned directly below the pressing indenter. The fixing roller has a core material diameter of 22 mm, a rubber thickness of 4 mm, and a roller having an outer diameter of 30 mm as a roller to measure the rubber hardness. In the measurement of rubber hardness, the hardness is measured in a state where rubber is installed on the surface of the core material.

  The fixing roller has three layers of a core metal, a solid rubber layer provided as an elastic layer so as to cover the outer peripheral surface of the core metal, and a sponge rubber layer provided so as to cover the outer peripheral surface of the solid rubber layer. Although it may have a structure, it is not limited to these.

  In the fixing roller, the core metal is preferably made of a metal material such as aluminum, iron, and SUS. The thickness of the cored bar is about 0.1 to 5 mm, but is more preferably about 0.1 to 1.5 mm in view of weight reduction and warm-up time. The diameter of the cored bar is preferably about 10 to 50 mm.

  As described above, the solid rubber layer and the sponge rubber layer are made of silicone rubber.

  Silicone rubber has heat resistance with respect to the fixing temperature and elasticity for ensuring the size of the area where the paper is pressed against (the length of the nip portion).

  The solid rubber layer is a solid hard layer. The thickness of the solid rubber layer 214 is preferably in the range of 5 to 10 mm, and more preferably in the range of 7 to 8 mm.

  On the other hand, the sponge rubber layer 216 is a sponge-like soft layer including an infinite number of microballoons. The thickness of the sponge rubber layer 216 is preferably in the range of 5 to 100 μm, and more preferably in the range of 80 to 90 μm.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

Example 1
The siloxane compounds and fluororesins described in Table I used in the examples are as follows.

(Siloxane compound)
Different types of M in general formula (1):
M = Me (methyl group): hexamethyldisiloxane (manufactured by Tokyo Chemical Industry) molecular weight 162.38 (abbreviated as HMDS in the table)
M = iPr (isopropyl group): 1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl) oxy] trisiloxane (manufactured by Tokyo Chemical Industry) molecular weight 310.69 (in the table, TMOS and (Abbreviation)
M = Ph (phenyl group): 1,3-dimethoxy-1,1,3,3-tetraphenyldisiloxane (manufactured by Tokyo Chemical Industry) molecular weight 442.66 (abbreviated as TPDS in the table)
M = Ph (phenyl group): Octaphenylcyclotetrasiloxane (manufactured by Tokyo Chemical Industry Co., Ltd.) Molecular weight 793.18 (abbreviated as OPTS in the table)
M = Me (methyl group) polyphenylmethylsiloxane (manufactured by Wako Pure Chemical Industries) Weight average molecular weight: 2700 (abbreviated as PPMS in the table)
(Fluorine resin)
Perfluoro (polyoxypropylene ethyl ether): (Wako Pure Chemical Industries, Ltd.) Weight average molecular weight: 5600 (abbreviated as PFPE1 in the table)
Perfluoro (polyoxypropylene ethyl ether): (Wako Pure Chemical Industries, Ltd.) Weight average molecular weight: 2700 (abbreviated as PFPE2 in the table)
Ethylene / tetrafluoroethylene copolymer: NEOFLON ETFE (manufactured by Daikin Industries) weight average molecular weight 10,000 (abbreviated as ETFE in the table)
Polytetrafluoroethylene: Polyfluorone PTFE (manufactured by Daikin Industries) Weight average molecular weight: 20000 (abbreviated as PTFE in the table)
Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer: NEOFLON PFA (manufactured by Daikin Industries) Weight average molecular weight 50000 (abbreviated as PFA in the table)
(Specific production method)
<Preparation of Fixing Belts 1-18 According to the Present Invention>
On the elastic layer made of polyimide film and silicone rubber as the base layer of the fixing belt after adding the combination of the above siloxane compound and fluororesin to the MEK (methyl ethyl ketone) solvent at the volume ratio shown in Table I and mixing with a mixer at room temperature Then, it was applied as a release layer and cured by thermosetting to form a fixing belt. Moreover, the thickness of the release layer was changed between 5 and 60 μm.

  The silicon content on the surface of the release layer was measured by X-ray photoelectron spectroscopy.

<XPS>
・ Analyzer: QUANTERA SXM manufactured by ULVAC-PHI
・ X-ray source: Monochromatic Al-Kα
・ Sputtering ion: Ar (2 keV)
Depth profile: Measurement is repeated at a predetermined thickness interval with a SiO ₂ equivalent sputtering thickness to obtain a depth profile in the depth direction. The thickness interval was 1 nm (data every 1 nm is obtained in the depth direction).
Quantification: The background was determined by the Shirley method, and quantified using the relative sensitivity coefficient method from the obtained peak area. Data processing uses MultiPak manufactured by ULVAC-PHI.

  From the obtained data, the average composition ratio of silicon from the surface of the release layer to 5 nm in the thickness direction was calculated. For the average composition ratio, 10 samples were randomly measured and the average value was used.

<Preparation of Comparative Fixing Belts 19-22>
Fixing belt 19: No siloxane compound was used, and only PFPE1 was used as the fluororesin.

  Fixing belt 20: A fluoropolymer having an organosiloxane functional group at the terminal was used.

  Fixing belt 21: Fluoro rubber was used as the fluororesin.

  Fixing belt 22: Silicone rubber was used as a siloxane compound.

≪Evaluation method≫
The fixing belt was installed as a fixing belt of an electrophotographic image forming apparatus equipped with a biaxial belt type fixing device. The roller constituting the fixing nip portion and supporting the fixing belt had a roller diameter of 60 mm. The surface temperature of each fixing belt is set to 180 ° C., and a toner image of a solid magenta belt image having a width of 5 cm in a direction perpendicular to the transport direction of the plain paper is transferred to A4 size plain paper. The fixed image of the belt-shaped image was formed on the plain paper through the fixing nip portion in the vertical direction at a speed of 60 sheets / minute.

<Image unevenness>
Observe solid images visually. Evaluation was made for image defects (roughness of appearance).

5 Level at which no image defect is seen in a solid image 4 Level of fine image defect is slightly visible when exposed to light 3 Level of no problem when exposed to light 3 Small image defect is observed when exposed to light 2 A fine image defect is seen in the solid image 1 An obvious image defect is seen in the solid image even if it is not exposed to light. Evaluation rank 3 or higher is acceptable.

<Fixing separation>
The separation property between each fixing belt and the plain paper was evaluated when solid images were fixed.

5 Separation without curling 4 Level at which paper curls a little, but no problem 3 There is paper that curls but is not at a level that causes paper jam 2 Although about 1/3 of the leading edge of plain paper can be separated, the rest is separated in the machine Paper jam occurs without releasing 1 All plain paper does not separate in the machine and causes paper jam Evaluation rank 3 or higher is acceptable.

  The configuration and evaluation results of the fixing belt are shown in Table I.

  From the results of Table I, it can be seen that the fixing belts 1 to 18 in which the siloxane compound and the fluororesin according to the present invention are mixed into the release layer as a composite material are excellent in fixing separation and image unevenness as compared with the comparative example.

  As the siloxane compound, M is preferably a methyl group in the structure represented by the general formula (1), and the relational formula (1): (molecular weight Mw of the siloxane compound) <(weight average molecular weight Mw of the fluororesin). Satisfying the fixing belt No. 5 and No. It can be seen from the comparison of 18 that it is preferable.

  Further, the effect of the present invention is that silicon is contained within the range of 3 to 50 at% on the surface, and the blend volume ratio of the siloxane compound and the fluororesin is within the range of 10:90 to 40:60. You can see that

DESCRIPTION OF SYMBOLS 10 Fixing belt 1 Base layer 2 Elastic layer 3 Release layer 100 Image forming apparatus main body 20 Operation display part 21 Operation display control part 22 LCD
DESCRIPTION OF SYMBOLS 30 Scanner part 301 Paper feeder 302 Scanner 31 Scanner control part 32 CCD sensor d Original 40 Image formation part 401 Printer control part 41 Image formation unit 411 Exposure part 411a LD
412 Developing unit 413 Photosensitive drum 414 Charging unit 42 Intermediate transfer unit 421 Intermediate transfer belt 422 Primary transfer roller 423A Secondary transfer roller Up
423 Support roller 426 Belt cleaning unit 43 Secondary transfer unit 431A Secondary transfer roller Lw
431 Support roller 432 Secondary transfer belt 50, 50a, 50b Paper feed unit 51a, 51b, 51c Paper feed tray unit S Paper 60 Fixing part 61 Fixing belt 62 Heating roller 63 Fixing roller 64 Pressure roller 65 Air separation part N Nip part 70 Paper transport section 72 Paper discharge section 72a Paper discharge roller 73 Transport path section 73a Registration roller pair

Claims (9)

A fixing member used for toner fixing of an electrophotographic image forming apparatus,
The fixing member has an elastic layer and a release layer on at least a base layer;
A fixing member, wherein the release layer contains a composite material in which a siloxane compound having a partial structure represented by the following general formula (1) and a fluororesin are mixed.
General formula (1) M-Si-O
(In the formula, M represents an unsubstituted or substituted monovalent hydrocarbon group.)   The fixing member according to claim 1, wherein the release layer contains silicon within a range of 3 to 50 at% on the surface.   The fixing member according to claim 1 or 2, wherein a blending volume ratio of the siloxane compound and the fluororesin in the composite material is within a range of 10:90 to 40:60.   The fluororesin contains any of polytetrafluoroethylene, perfluoroalkoxyalkane, perfluoropolyether, fluorinated acrylic, fluorinated ethylene-vinyl ether copolymer and fluorinated ethylene-vinyl ester copolymer. The fixing member according to claim 1, wherein the fixing member is a fixed member.   The fixing member according to any one of claims 1 to 4, wherein M is a methyl group in the structure represented by the general formula (1). In the siloxane compound and fluororesin contained in the composite material,
The fixing member according to any one of claims 1 to 5, wherein the following relational expression (1) is satisfied.
Relational expression (1): (Molecular weight Mw of siloxane compound) <(Weight average molecular weight Mw of fluororesin) A method for manufacturing a fixing member for manufacturing the fixing member according to any one of claims 1 to 6,
A step of adding a siloxane compound satisfying the following relational expression (1) and a fluororesin to a solvent and mixing the mixture with a mixer to obtain a mixture;
Applying the mixture onto an elastic layer made of silicone rubber, and thermally curing the applied mixture to form a release layer made of a composite material of the siloxane compound and fluororesin;
A method for manufacturing a fixing member, comprising:
Relational expression (1): (Molecular weight Mw of siloxane compound) <(Weight average molecular weight Mw of fluororesin)   An image forming apparatus comprising the fixing member according to claim 1.   An image forming method using the fixing member according to any one of claims 1 to 6.

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