JP2012194281A - Component for image forming apparatus, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a component for an image forming apparatus that is excellent in wear resistance and mold releasability.SOLUTION: A component for an image forming apparatus comprises a single-layered body containing an organic group partially having a hydroxyl group between repeating structural units containing a tetravalent organic group having one or more aromatic rings, and a polyimide resin or a precursor thereof in which a specific structural unit containing an organic group having fluorine atoms is included.

Description

  The present invention relates to an image forming apparatus member, a fixing device, and an image forming apparatus.

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, a toner image formed on a recording sheet is fixed by a fixing device to form an image.

For example, regarding a fixing device, Patent Document 1 proposes a “fixing device called a belt nip system including a fixing roll and a pressure belt that can run while being in contact with the fixing roll”.
Patent Documents 2 and 3 also state that “a combination of highly wear-resistant polyimide and fluororesin is used, and the fluororesin is deposited and unevenly distributed on the belt surface, so that both wear resistance and releasability are achieved. An endless belt for the purpose has been proposed.
Patent Document 4 proposes “an endless belt containing fluorinated polyimide as a main component for the purpose of maintaining release properties in a highly wear-resistant polyimide”.

In addition, Patent Document 5 proposes “a belt for an image forming apparatus in which a polymer contains an epoxy group such as a glycidyl methacrylate group”.
Patent Document 6 proposes “a sliding member containing an epoxy group-containing silane-modified resin in a coating agent for forming a coating layer”.

Japanese Patent No. 3298354 Japanese Patent Laid-Open No. 11-156971 JP 2006-256323 A Japanese Patent No. 3069041 Japanese Patent Laying-Open No. 2005-084247 Japanese Patent Application Laid-Open No. 08-238718

  An object of the present invention is to provide a member for an image forming apparatus having excellent wear resistance and releasability.

The above problem is solved by the following means. That is,
The invention according to claim 1
A surface comprising a polyimide resin having a repeating structural unit represented by the following general formula (1) and having a structural unit represented by the following general formula (2) partially interposed between the structural units of the repeating structural unit A member for an image forming apparatus.

(In the general formulas (1) and (2), Ar represents a tetravalent organic group having one or more aromatic rings.
Y represents a divalent organic group.
R represents an organic group having a hydroxyl group.
X represents an organic group having a fluorine atom.
n represents an integer of 1 or more. )

The invention described in claim 2
The image forming apparatus member according to claim 1, wherein X in the general formula (2) represents an organic group having 3 to 20 fluorine atoms.

The invention according to claim 3
3. The member for an image forming apparatus according to claim 1, wherein a fluorine atom content measured by X-ray photoelectron spectroscopy on the surface of the layer containing the polyimide resin is 5% or more and 60% or less.

The invention according to claim 4
A member for an image forming apparatus, comprising a layer containing a polyimide resin obtained by imidizing a polyamic acid resin obtained by reacting an epoxy compound having a fluorine atom with some structural units of a repeating structural unit.

The invention according to claim 5
A heating member, and a pressure member disposed in contact with the heating member,
5. A fixing device in which at least one of the heating member and the pressure member includes the image forming apparatus member according to claim 1.

The invention according to claim 6
An image carrier,
Latent image forming means for forming a latent image on the surface of the image carrier;
Developing means for developing the latent image with toner to form a toner image;
Transfer means for transferring the toner image to a recording medium;
Fixing means for fixing the toner image to the recording medium;
With
The image forming apparatus according to claim 5, wherein the fixing unit is a fixing device.

According to the invention of claim 1, when a polyimide resin in which the structural unit represented by the general formula (2) is not partially interposed between the structural units of the repeating structural unit represented by the general formula (1) is employed. In comparison, it is possible to provide a member for an image forming apparatus having excellent wear resistance and releasability.
According to the second aspect of the invention, there is provided an image forming apparatus member having excellent wear resistance and releasability as compared with the case where the number of fluorine atoms of the organic group represented by X in the general formula (2) is outside the above range. Can be provided.
According to the invention of claim 3, it is possible to provide an image forming apparatus member that is excellent in wear resistance and releasability as compared with the case where the fluorine atom content on the surface of the layer containing the polyimide resin is out of the above range. .

  According to the invention of claim 4, compared to the case where a polyamic acid that does not react with an epoxy compound having a fluorine atom is used for some structural units of the repeating structural unit, it has excellent wear resistance and releasability. A member for an image forming apparatus can be provided.

  According to the inventions according to claims 5 and 6, a polyimide resin in which the structural unit represented by the general formula (2) is not partially interposed between the structural units of the repeating structural unit represented by the general formula (1) is employed. As compared with a case where an image forming apparatus member is provided, it is possible to provide a fixing apparatus and an image forming apparatus in which fixing defects due to a decrease in wear resistance and releasability of the image forming apparatus member are suppressed.

1 is a schematic diagram illustrating a configuration of a fixing device according to a first embodiment. FIG. 6 is a schematic diagram illustrating a configuration of a fixing device according to a second embodiment. 1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

[Image forming apparatus member]
The image forming apparatus member (hereinafter referred to as an endless belt) according to the present embodiment is formed, for example, in an endless manner, for example, a layer containing a polyimide resin having a thickness of 30 μm to 200 μm (hereinafter referred to as a polyimide resin layer). It is composed of a single layer.
And as a polyimide resin, the polyimide resin which has a repeating structural unit represented by General formula (1), and the structural unit shown by General formula (2) partially intervened between the structural units of the said repeating structural unit. Apply.

  In the endless belt according to the present embodiment, by adopting the above-described configuration, the wear resistance and the releasability are excellent.

Here, there is a technology for realizing an endless belt having both wear resistance and releasability by mixing polyimide resin and fluororesin and precipitating and unevenly distributing fluororesin on the belt surface (Patent Documents 2 to 3). As is known, in the present technology, there is a tendency that less fluororesin is exposed on the surface of the endless belt, and it is difficult to improve the releasability, and when the amount of the fluororesin is increased to improve the releasability, The mechanical strength of the endless belt tends to decrease.
Also, a technique using a fluorinated polyimide resin (Patent Document 4) is known. However, the fluorinated polyimide resin has a fluorine atom content of, for example, less than 40% even in a commercially available fully fluorinated polyimide. At present, there is a limit to improving moldability.

In contrast, a polyimide resin in which the structural unit represented by the general formula (2) is partially interposed between the structural units of the repeating structural unit represented by the general formula (1) is represented by the general formula (1). The fluorine-containing group (—O—R—X) contained in the structural unit represented by the general formula (2) easily moves while maintaining the mechanical strength derived from the structural unit. It has a structure and is considered to be easily oriented and unevenly distributed.
For this reason, it is thought that the polyimide resin layer comprised with this polyimide resin can raise the fluorine atom content rate of the surface, raising mechanical strength.

  Therefore, the endless belt according to the present embodiment is considered to be excellent in wear resistance and releasability.

  Hereinafter, constituent materials and characteristics of the endless belt according to the present embodiment will be described in detail.

(Polyimide resin layer)
A polyimide resin layer is comprised including a polyimide resin and another additive as needed.

Specifically, for example, the polyimide resin layer is a layer formed of a resin composition including a precursor of a specific polyimide resin and a solvent for dissolving the precursor of the polyimide resin.
That is, the polyimide resin layer is a layer obtained by subjecting the coating film of the resin composition to a heat treatment, causing an imidization reaction of the precursor of the specific polyimide resin, and forming the specific polyimide resin. .

  The resin composition for forming the polyimide resin layer includes, for example, a polyimide resin precursor, an inorganic lubricating powder having a layered structure, and a solvent for dissolving the polyimide resin precursor, as necessary, a filling material, An additive such as a tertiary amine, a carboxylic acid anhydride, or a dispersant as a catalyst may be included.

-Polyimide resin (its precursor)-
The polyimide resin (precursor thereof) will be described.
The polyimide resin has a repeating structural unit represented by the general formula (1), and a polyimide resin in which the structural unit represented by the general formula (2) is partially interposed between the structural units of the repeating structural unit (hereinafter referred to as “polyimide resin”). , Referred to as a specific polyimide resin).

In general formulas (1) and (2), Ar represents a tetravalent organic group having one or more aromatic rings.
Y represents a divalent organic group.
R represents an organic group having a hydroxyl group.
X represents an organic group having a fluorine atom.
n represents an integer of 1 or more.

Here, in the general formulas (1) and (2), the “tetravalent organic group having one or more aromatic rings” represented by Ar has four carbonyl groups from the starting aromatic tetracarboxylic dianhydride. The specific aromatic tetracarboxylic dianhydride is, for example, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride. 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic acid Examples thereof include acid dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, and the like.
Among these, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride are desirable.

In the general formulas (1) and (2), the “divalent organic group” represented by Y is a residue obtained by removing two amino groups from a diamine compound as a raw material. Are, for example, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, 4, 4'-diaminodiphenyl sulfone is mentioned.
Among these, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3- Dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3 , 3-trimethylindane, 4,4′-diaminobenzanilide, 3,5-diamino-3′-trifluoromethylbenzanilide, 3,5-diamino-4′-trifluoromethylbenzanilide, 3,4′- Diaminodiphenyl ether, 2,7-diaminofluorene, 2,2-bis (4-aminophenyl) hexafluoropropane are preferred .

  In the general formulas (1) and (2), the “organic group having a hydroxyl group” represented by R is, for example, 2 to 10 carbon atoms substituted with one or more hydroxyl groups (desirably 2 to 8 carbon atoms). And an alkylene group having 2 to 6 carbon atoms), a fluoroalkylene group in which some or all of the hydrogen atoms are substituted with fluorine atoms, and the like.

  In the general formulas (1) and (2), examples of the organic group having a fluorine atom represented by X include a fluorinated alkyl group.

Specific examples of the fluorinated alkyl group include, for example, — (CF ₂ ) _m1 —Xa (where m1 represents a natural number of 0 or more and 20 or less. Xa represents —CH ₂ F group, —CHF ₂ group, or —CF Represents ₃ groups).
m1 represents a natural number of 0 or more and 20 or less, preferably a natural number of 0 or more and 15 or less, more preferably a natural number of 0 or more and 10 or less.
Xa represents a —CH ₂ F group, a —CHF ₂ group, or a —CF ₃ group, and preferably a —CHF ₂ group or a —CF ₃ group.

Here, the organic group having a fluorine atom represented by X is an organic group having 3 or more and 20 or less (preferably 5 or more and 20 or less, more preferably 10 or more and 20 or less) fluorine atoms. Is good.
When the number of fluorine atoms is within the above range, the releasability is easily improved together with the wear resistance of the endless belt (polyimide resin layer).

  In general formulas (1) and (2), n represents an integer of 1 or more, and desirably represents an integer of 50 or more and 10000000 or less. Note that n represents the degree of polymerization.

Here, in the specific polyimide resin, the ratio of the structural unit represented by the general formula (2) to the repeating structural unit represented by the general formula (1) is, for example, the repeating structural unit represented by the general formula (1). The structural unit represented by the general formula (2) may be in the range of 1 to 1000, preferably in the range of 50 to 800, more preferably in the range of 100 to 500. .
When the ratio is within the above range, the releasability is easily improved together with the wear resistance of the endless belt (polyimide resin layer).

  On the other hand, as a precursor of the specific polyimide resin, for example, a polyamic acid resin that changes to an imide ring through an imidization reaction, specifically, a repeating structural unit represented by the general formula (11), A polyamic acid resin (hereinafter referred to as a specific polyamic acid resin) in which the structural unit represented by the general formula (21) is partially interposed between the structural units of the repeating structural unit is applied.

  In general formulas (11) and (21), Ar, Y, R, X, and n are as defined in general formulas (1) and (2).

The specific polyamic acid resin, which is the precursor of the specific polyimide resin, produces a polyamic acid resin by polymerizing equimolar amounts of tetracarboxylic dianhydride and diamine compound in an organic polar solvent as shown in the following scheme. Then, it is obtained by reacting this with an epoxy compound having a fluorine atom (O ₃ -R—X: where R and X are the same as those in formulas (1) and (2)). Specifically, among two carboxylic acids possessed by some structural units of the polyamic acid resin repeating structural unit (general formula (11)), one carboxylic acid and an epoxy compound having a fluorine atom are reacted, A specific polyamic acid resin is obtained.
That is, the specific polyimide resin is a polyimide resin obtained by imidizing a specific polyamic acid obtained by reacting an epoxy compound having a fluorine atom with some structural units of the repeating structural unit.
The obtained specific polyamic acid resin may be a polyamic acid-polyimide copolymer that has been partially imidized.

  There is no restriction | limiting in particular as tetracarboxylic dianhydride for forming specific polyamic acid resin, An aromatic tetracarboxylic dianhydride is mentioned.

  Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzoenone tetracarboxylic dianhydride, 3,3 ′, 4,4 ′. -Biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ', 4,4 '-Biphenyl ether tetracarboxylic dianhydride, 3,3', 4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilane tetracarboxylic dianhydride 1,2,3,4-furantetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-di Carboxyphe Xyl) diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (Triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, and the like.

Examples of tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic acid dianhydride. Anhydrous is desirable.
These tetracarboxylic dianhydrides are used alone or in combination of two or more.

The diamine compound for forming the specific polyamic acid resin is not particularly limited as long as it is a diamine compound having two amino groups in the molecular structure.
Examples of the diamine compound include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide. 4,4′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3 -Trimethylindane, 6-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 4,4'-diaminobenzanilide, 3,5-diamino-3'-trifluoromethylbenzanilide 3,5-diamino-4′-trifluoromethylbenzanilide, 3,4′-diaminodiphenyl ether, , 7-diaminofluorene, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,5′-tetrachloro-4 , 4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diamino -2,2'-bis (trifluoromethyl) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoro Propane, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) -biphenyl, 1,3′-bis (4-aminophenoxy) benzene, 9,9-bi (4-aminophenyl) fluorene, 4,4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) bisaniline, 2,2′-bis [4- (4-amino- Aromatic diamines such as 2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-bis [4- (4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl; diaminotetraphenylthiophene, etc. An aromatic diamine having two amino groups bonded to the aromatic ring and a hetero atom other than the nitrogen atom of the amino group; 1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, penta Methylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminohe Tamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylenediethylenediamine, tricyclo [6,2,1,02.7]- Examples thereof include aliphatic diamines such as undecylenedimethyldiamine and 4,4′-methylenebis (cyclohexylamine), and alicyclic diamines.

As the diamine compound, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, and 4,4′-diaminodiphenyl sulfone are desirable.
These diamine compounds are used alone or in combination of two or more.

The epoxy compound having a fluorine atom (hereinafter referred to as fluorine-containing epoxide) for forming the specific polyamic acid resin is not particularly limited as long as it is an epoxy compound (epoxide) having a fluorine atom in the molecular structure.
Examples of the epoxy compound having a fluorine atom include hexafluoroepoxypropane, 3-perfluorobutyl-1,2-epoxypropane, 3-perfluorohexyl-1,2-epoxypropane, hexafluoropropylene, perfluoro (propyl). Vinyl ether), 3-perfluorobutyl-1,2-epoxypropane, 3- (1H, 1H, 5H-octafluoropentyloxy) -1,2-epoxypropane, 3- [2- (perfluorohexyl) ethoxy]- 1,2-epoxypropane, 3,3,3-trifluoro-1,2-epoxypropane, 3-perfluorobutyl-1,2-epoxypropane, 3-perfluoroethyl-1,2-epoxypropane, 3, -Perfluoropropyl-1,2-epoxypropane, 3-perf Orohekishiru 1,2-epoxypropane, 3-perfluorooctyl-1,2-epoxypropane, and the like.

These fluorine-containing epoxides are used alone or in combination of two or more.

Here, the addition amount of the fluorine-containing epoxide (O ₃ —R—X) is, for example, 0.1% by mass or more and 90% by mass or less with respect to the solid content (polyamic acid resin) of the produced polyamic acid resin solution. Preferably, it is 1 to 80% by mass, more preferably 5 to 70% by mass.
When this addition amount is within the above range, the releasability is easily improved together with the wear resistance of the endless belt (polyimide resin layer).

  Examples of the organic polar solvent used in the reaction for producing the specific polyamic acid resin include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide. Acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m-, or Phenolic solvents such as p-cresol, xylenol, halogenated phenol, catechol, ether solvents such as tetrahydrofuran, dioxane, dioxolane, alcohol solvents such as methanol, ethanol, butanol, cellosolve such as butyl cellosolve, or Kisa methyl phosphoramide, .gamma.-butyrolactone, etc. can be mentioned, but it is desirable to use them alone or as a mixture, further xylene, can also be used aromatic hydrocarbons such as toluene. The solvent is not particularly limited as long as it dissolves the polyamic acid resin.

  Further, the solid content concentration of the solvent at the time of producing the specific polyamic acid resin is not particularly specified, but is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 30% by mass or less.

  Moreover, as reaction temperature at the time of production | generation (at the time of superposition | polymerization) of specific polyamic acid resin, it is good in the range of 0 degreeC or more and 80 degrees C or less, for example.

  In addition, when a specific polyamic acid resin is partially imidized to form a polyamic acid-polyimide copolymer, a method of imidizing the polyamic acid resin by heat treatment, or a dehydrating agent and / or a catalyst is allowed to act chemically. By the imidization method, at least a part of the polyamic acid structure in the polyamic acid resin is converted to an imide group by a dehydration ring-closing reaction.

  Here, the heating temperature in the method of imidizing by heat treatment is usually 60 ° C. or more and 200 ° C. or less, and preferably 100 ° C. or more and 170 ° C. or less.

  On the other hand, in the method of chemically imidizing, a dehydrating agent and / or a catalyst is added to the specific polyamic acid resin solution to chemically advance the imidization reaction. The dehydrating agent is not particularly limited as long as it is a monovalent carboxylic anhydride. For example, one kind or two or more kinds selected from acid anhydrides such as acetic anhydride, propionic acid anhydride, trifluoroacetic acid anhydride, butanoic acid anhydride, and oxalic acid anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 mol or more and 2 mol or less with respect to 1 mol of the repeating structural unit of the specific polyamic acid resin.

In the method of chemically imidizing, as the catalyst to be used, for example, one kind or two or more kinds selected from tertiary amines such as pyridine, picoline, collidine, lutidine, quinoline, isoquinoline, and triethylamine can be used. It is not limited to these. The amount of the catalyst used is preferably 0.01 mol or more and 2 mol or less with respect to 1 mol of the dehydrating agent to be used.
The reaction for chemically imidizing is performed by adding a dehydrating agent and / or a catalyst to the polyamic acid resin solution and heating as necessary. The reaction temperature for dehydration and ring closure is usually 0 ° C. or higher and 180 ° C. or lower, preferably 60 ° C. or higher and 150 ° C. or lower.

  Note that the dehydrating agent and / or the catalyst that acted on the polyamic acid-polyimide copolymer need not be removed, but may be removed by the following method. As a method for removing the dehydrating agent and / or the catalyst that has acted, heating under reduced pressure or a reprecipitation method can be used. The reduced pressure heating is performed at a temperature of 80 ° C. or higher and 120 ° C. or lower under vacuum to distill off the tertiary amine, unreacted dehydrating agent and hydrolyzed carboxylic acid used as a catalyst. The reprecipitation method uses a poor solvent that dissolves the catalyst, the unreacted dehydrating agent and the hydrolyzed carboxylic acid, and does not dissolve the polyamic acid-polyimide copolymer. This is done by adding liquid. The poor solvent is not particularly limited, and water, alcohol solvents such as methanol and ethanol, ketone solvents such as acetone and methyl ethyl ketone, hydrocarbon solvents such as hexane, and the like can be used. The precipitated polyamic acid-polyimide copolymer is dissolved in a solvent such as γ-butyrolactone and N-methyl-2-pyrrolidone after filtration and drying.

-Solvent-
The solvent used for the resin composition for forming the polyimide resin layer will be described.
Examples of the solvent include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N-dimethylacetamide, and N, N-diethylacetamide. Acetamide solvents, N-methyl-2-pyrrolidone, pyrrolidone solvents such as N-vinyl-2-pyrrolidone, phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol , Ether solvents such as tetrahydrofuran, dioxane, dioxolane, alcohol solvents such as methanol, ethanol, butanol, cellosolve such as butyl cellosolve, hexamethylphosphoramide, γ-butyrolactone, etc. Can, but it is desirable to use them alone or as a mixture, further xylene, it can also be used aromatic hydrocarbons such as toluene.
The solvent is not particularly limited as long as it dissolves the precursor of the specific polyimide resin.

  The solvent may be used from the time of synthesizing the specific polyamic acid resin, which is a precursor of the specific polyimide resin, or may be replaced with a target solvent after synthesizing the specific polyamic acid resin. For solvent replacement, add the target amount of solvent to the solution of the specific polyamic acid resin after synthesis and dilute, re-precipitate the specific polyamic acid resin after synthesis and then redissolve in the target solvent. Or a method of adjusting the composition by adding a target solvent while gradually distilling off the solvent.

-Filling material-
The filling material will be described.
The filling material is added for the purpose of imparting conductivity, improving durability, improving thermal conductivity, and improving surface slipperiness.
The filling material may be at least one selected from the group consisting of metal oxide fine particles, silicate minerals, carbon black, and nitrogen compounds, for example.
Among these, ketjen black, graphite, acetylene black, BaSO4, zeolite, silicon oxide, tin oxide, copper oxide, iron oxide, zirconium oxide, ITO (tin-doped indium oxide), AZO (aluminum-added zinc oxide), Sb doped Desirably, at least one selected from SnO ² -coated TiO ₂ , silicon nitride, boron nitride, titanium nitride, mica, and the like.
The filler material may be used alone or in combination of two or more.
The average particle diameter of the filling material is preferably 0.01 μm or more and 20 μm, for example.

  The content of the filling material is, for example, preferably 0.01 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of all resin components.

-Tertiary amine-
The tertiary amine used in the resin composition for forming the polyimide resin layer will be described.
The tertiary amine works as a catalyst for imidization reaction, and for example, one or more selected from pyridine, picoline, collidine, lutidine, quinoline, isoquinoline, and triethylamine are preferable.

  The content of the tertiary amine is, for example, preferably from 0.1 to 30 parts by mass with respect to 100 parts by mass of all resin components.

-Carboxylic anhydride-
The carboxylic acid anhydride used for the resin composition for forming the polyimide resin layer will be described.
Carboxylic anhydride serves as a dehydrating agent during the imidization reaction and promotes the imidization reaction. Examples of the carboxylic acid anhydride include acetic anhydride, trifluoroacetic acid anhydride, propionic acid anhydride, butanoic acid anhydride, oxalic acid anhydride, and the like. Among these, acetic anhydride is preferable. These may be used alone or in combination of two or more.

  The content of the carboxylic acid anhydride is, for example, preferably from 0.1 parts by weight to 30 parts by weight with respect to 100 parts by weight of the total resin components.

-Dispersant-
The dispersant used for the resin composition for forming the polyimide resin layer will be described.
The dispersant is used to disperse the filler (particulate filler), which may be low molecular weight or high molecular weight, and any kind of dispersion selected from cationic, anionic and nonionic Among them, nonionic polymers are particularly desirable.
Nonionic polymers include poly (N-vinyl-2-pyrrolidone), poly (N, N′-diethylacrylazide), poly (N-vinylformamide), poly (N-vinylacetamide), poly (N -Vinylphthalamide), poly (N-vinylsuccinic acid amide), poly (N-vinylurea), poly (N-vinylpiperidone), poly (N-vinylcaprolactam), poly (N-vinyloxazoline) and the like. A single or a plurality of nonionic polymers may be added.
The amount of the dispersant added may be, for example, 0.2 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of all resin components.

-Characteristics of resin composition for forming polyimide resin layer-
The solid content concentration of the resin composition is not particularly defined, but is selected based on the ease of the coating process when manufacturing the endless belt. In terms of coating, the viscosity of the resin composition is generally preferably, for example, from 1 Pa · s to 100 Pa · s, and the solid content concentration of the resin composition having the viscosity is, for example, a coating solvent (for example, an organic polar solvent) 10 mass% or more and 40 mass% or less are desirable with respect to 100 mass parts.

(Characteristics of endless belt)
Next, the characteristics of the endless belt according to the present embodiment will be described.
The surface (surface layer portion) of the endless belt (polyimide resin layer) according to this embodiment may have a fluorine atom content of 5% to 60%, preferably 10% to 55%, and more preferably 20% or more and 50% or less.
When the fluorine atom content is in the above range, the releasability is easily improved along with the wear resistance of the endless belt (polyimide resin layer).

The fluorine content is a value measured using X-ray photoelectron spectroscopy (hereinafter also referred to as XPS).
Specifically, “VG ESCALAB-220i” is used as an XPS measurement device, and measurement is performed using a monochromatic AlKα ray as an X-ray source, setting an acceleration voltage to 10 kV, and an emission current to 20 mV. Measure for fluorine atoms. The analysis region is about 1 mmφ and the detection depth is 5 nm. And about a fluorine atom, C1s spectrum is measured, the number of elements is calculated | required based on the spectrum of the said fluorine atom, and the fluorine atom content rate with respect to the total atomic weight of specific polyimide resin is calculated.

(Endless belt manufacturing method)
Hereinafter, the manufacturing method of the endless belt according to the present embodiment will be described.
First, a core body is prepared. Examples of the core to be prepared include a cylindrical mold. Examples of the core material include metals such as aluminum, stainless steel, and nickel. The length of the core needs to be longer than the target endless belt, but is preferably 10% to 40% longer than the target endless belt.

Next, the specific polyamic acid resin solution is applied to a cylindrical mold as a core material to form a coating film of the specific polyamic acid resin solution.
The method of applying the specific polyamic acid resin solution to the cylindrical mold is not particularly limited. For example, the method of immersing in the outer peripheral surface of the cylindrical mold, the method of applying to the inner peripheral surface of the cylindrical mold, the shaft For example, a method of coating the outer peripheral surface or inner peripheral surface of the cylindrical mold with the “spiral coating method” or the “die method coating method” while rotating the cylindrical mold.

  Next, the coating film of the specific polyamic acid resin solution is dried to form a coating film (dried coating film before imidization) to be a polyimide base layer. The drying conditions are, for example, from 80 ° C. to 200 ° C. for 10 minutes to 60 minutes, and the higher the temperature, the shorter the heating time. It is also effective to apply hot air during heating. During heating, the temperature may be increased stepwise or increased without changing the speed. It is preferable to rotate the core body at 5 rpm or more and 60 rpm or less with the axial direction of the core body horizontal. The core may be vertical after drying.

Next, heat treatment is performed on the film to be the polyimide resin layer.
This heat treatment is performed under conditions (temperature / time) under which the specific polyamic acid resin of the film to be the polyimide resin layer is imidized.
And after performing this heat processing, a membrane | film | coat is extracted from a core. Thereby, the endless belt comprised by the single layer body of the polyimide resin layer is obtained.

  Here, as heating conditions for imidization (firing), for example, by heating at 250 ° C. or higher and 450 ° C. or lower (desirably 300 ° C. or higher and 350 ° C. or lower) for 20 minutes or longer and 60 minutes or shorter, an imidization reaction occurs, A polyimide resin film is formed. In the heating reaction, before reaching the final temperature of heating, it is preferable to heat by gradually increasing the temperature stepwise or at a constant rate.

  Further, heating for drying and heating for imidization (firing) are preferably performed in a hydrophobic atmosphere environment (for example, in an atmosphere of nitrogen gas, helium gas, neon gas, argon gas, or krypton gas). Thereby, it is considered that the fluorine-containing group (—O—R—X) possessed by the specific polyimide resin moves to the polyimide resin layer surface, and is easily oriented and unevenly distributed, and the fluorine atom content rate on the surface of the formed polyimide resin layer Will improve.

The endless belt according to the present embodiment described above has been described as having a single layer structure of a polyimide resin layer. However, the endless belt is not limited to this. For example, a laminate of two or more layers having a polyimide resin layer as a surface layer is used. Specifically, for example, a two-layer structure laminate of a base material layer having a thickness of 30 μm or more and 120 μm or less and a surface layer (polyimide resin layer) having a thickness of 5 μm or more and 70 μm or less provided on the outer peripheral surface of the base material layer 12 An intermediate layer (for example, endless) between any one of the three-layer structure laminate, the two-layer structure laminate, and the three-layer structure laminate further having a polyimide resin layer on the inner peripheral surface of the base layer of the two-layer structure laminate When the belt is applied as an electromagnetic induction heating type heating belt, a multilayer structure laminate having a metal heating layer or the like may be used.
In addition, as a base material layer, for example, a resin material (for example, a polyester resin formed by adding a polyimide resin, a polyamide resin, a polyamideimide resin, a polyether ether ester resin, a polyarylate resin, a polyester resin, a reinforcing material, or the like) And other additives such as fillers as necessary.

In this embodiment, the endless belt as the image forming apparatus member has been described. However, the endless belt is not limited to the belt member, and the image forming apparatus member may be a roll member as long as it has a polyimide resin layer on the surface. There may be.
As the roll member, a core metal (for example, a cylindrical base material made of metal such as aluminum, SUS, iron, copper, alloy, ceramics, FRM (fiber reinforced metal)) and a polyimide resin layer of 2 μm or more and 100 μm or less on the outer peripheral surface thereof. The roll member which has as a surface layer is mentioned, You may have an elastic layer (For example, the elastic layer comprised by silicone rubber and fluororubber) between the metal core and the surface layer (polyimide resin layer).

  The image forming apparatus member (endless belt or other roll-shaped member) according to the present embodiment includes, for example, an intermediate transfer member, a recording medium conveyance transfer member, a recording medium conveyance member, and a fixing member (heating member or pressure member). And the like as a member for an image forming apparatus.

[Fixing device]
Hereinafter, an example of the fixing device according to the present embodiment will be described.
The fixing device according to the present embodiment has various configurations. Hereinafter, as the first embodiment, a fixing device including a heating roll having a heating source and a pressure belt pressed by a pressure pad will be described. As a second embodiment, a fixing device including a heating belt pressed by a heat source and a pressure roll will be described.
The member for an image forming apparatus according to this embodiment is applied as a heating belt and a pressure belt in these fixing devices.
The member for an image forming apparatus according to this embodiment may be applied as a heating roll, a pressure roll, a sliding sheet, or the like.

-First Embodiment of Fixing Device-
First, the fixing device 60 according to the first embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of a fixing device 60 according to the first embodiment.

  As shown in FIG. 1, the fixing device 60 according to the first embodiment adds a heating roll 61 as an example of a rotating body that is rotationally driven, a pressure belt 62, and a heating roll 61 via the pressure belt 62. And a pressure pad 64 as an example of a pressure member to be pressed. The pressure pad 64 only needs to be relatively pressurized with the pressure belt 62 and the heating roll 61. Therefore, the pressure belt 62 side may be pressed by the heating roll 61, and the heating roll 61 side may be pressed by the heating roll 61.

  The heating roll 61 is configured by laminating a heat-resistant elastic body layer 612 and a release layer 613 around a metal core (cylindrical cored bar) 611. Inside the heating roll 61, a halogen lamp 66 is disposed as an example of a heating unit for heating the unfixed toner image in the sandwiching area. The heating means is not limited to the halogen lamp, and other heat generating members that generate heat may be used.

  On the other hand, a temperature sensitive element 69 is disposed in contact with the surface of the heating roll 61. The lighting of the halogen lamp 66 is controlled based on the temperature measurement value by the temperature sensing element 69, and the surface temperature of the heating roll 61 is maintained at a predetermined set temperature (for example, 150 ° C.).

  The pressure belt 62 is rotatably supported by a pressure pad 64 and a belt traveling guide 63 disposed inside, and edge guides 80 disposed at both ends described later. And it is arranged in pressure contact with the heating roll 61 in the sandwiching region N.

  The pressure pad 64 is disposed inside the pressure belt 62 in a state of being pressed by the heating roll 61 via the pressure belt 62, and forms a sandwiching region N between the pressure pad 64 and the heating roll 61. The pressure pad 64 has a pre-clamping member 64a for securing a wide clamping region N arranged on the inlet side of the clamping region N, and sandwiches a peeling clamping member 64b for distorting the heating roll 61. It is arranged on the exit side of the insertion area N.

  Further, in order to reduce the sliding resistance between the inner peripheral surface of the pressure belt 62 and the pressure pad 64, a sliding sheet 68 is provided on the surface of the front sandwiching member 64a and the peeling sandwiching member 64b in contact with the pressure belt 62. Is provided. The pressure pad 64 and the sliding sheet 68 are held by a metal holding member 65.

  Further, a belt traveling guide 63 is attached to the holding member 65 so that the pressure belt 62 rotates.

  The heating roll 61 is rotated in the direction of arrow C by a drive motor (not shown), and the pressure belt 62 is rotated in the direction opposite to the rotation direction of the heating roll 61 following the rotation. That is, the heating roll 61 rotates in the clockwise direction in FIG. 1, whereas the pressure belt 62 rotates in the counterclockwise direction.

  The sheet K (recording medium) having the unfixed toner image is guided by the fixing inlet guide 56 and conveyed to the sandwiching area N. When the paper K passes through the sandwiching area N, the toner image on the paper K is fixed by the pressure acting on the sandwiching area N and the heat supplied from the heating roll 61.

  In the fixing device 60 according to the first embodiment, the concave front sandwiching member 64a that follows the outer peripheral surface of the heating roll 61 secures a wide sandwiching region N as compared with the configuration without the front sandwiching member 64a. .

  Further, in the fixing device 60 according to the first embodiment, the peeling of the heating roll 61 is disposed so as to protrude from the outer peripheral surface of the heating roll 61, so that the distortion of the heating roll 61 is locally generated in the exit area of the clamping area N. It is comprised so that it may become large automatically.

  If the peeling and clamping member 64b is arranged in this way, the paper K after fixing passes through the locally formed distortion when passing through the peeling and clamping area, so that the paper K is heated. Easy to peel off from the roll 61.

  In addition, a peeling member 70 is disposed on the downstream side of the sandwiching region N of the heating roll 61 as an auxiliary means for peeling. The peeling member 70 is held by the holding member 72 in a state where the peeling claw 71 is close to the heating roll 61 in a direction (counter direction) opposite to the rotation direction of the heating roll 61.

-Second Embodiment of Fixing Device-
Next, the fixing device 90 according to the second embodiment will be described. FIG. 2 is a schematic diagram illustrating a configuration of the fixing device 90 according to the second embodiment.
Note that the same components as those of the fixing device according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted here.

  As shown in FIG. 2, the fixing device 90 according to the second embodiment includes a heating belt 92 and a pressure roll 91.

  The heating belt 92 is disposed on the toner image holding surface side of the paper K, and a ceramic heater 82 that is a resistance heating element as an example of a heating unit is disposed inside the heating belt 92. Is configured to supply heat to the sandwiching region N.

  The ceramic heater 82 has a substantially flat surface on the pressure roll 91 side. And it arrange | positions in the state pressurized by the pressurization roll 91 via the heating belt 92, and forms the clamping area | region N. FIG. Therefore, the ceramic heater 82 also functions as a pressure member. The paper K that has passed through the sandwiching area N is peeled from the heating belt 92 by the change in the curvature of the heating belt 92 in the exit area (peeling sandwiching portion) of the sandwiching area N.

  Further, a sliding sheet 68 is disposed between the inner peripheral surface of the heating belt 92 and the ceramic heater 82 in order to reduce the sliding resistance between the inner peripheral surface of the heating belt 92 and the ceramic heater 82. The sliding sheet 68 may be configured separately from the ceramic heater 82 or may be configured integrally with the ceramic heater 82.

  On the other hand, the pressure roll 91 is disposed so as to face the heating belt 92, and is configured to rotate in the direction of arrow D by a drive motor (not shown), and the heating belt 92 rotates following the rotation. The pressure roll 91 includes a core (columnar core) 911, a heat-resistant elastic body layer 912 coated on the outer peripheral surface of the core 911, and a release layer 913 made of a heat-resistant resin coating or a heat-resistant rubber coating. As necessary, each layer is made semiconductive by adding carbon black or the like as a countermeasure against toner offset.

  Further, the peeling member 70 may be disposed on the downstream side of the sandwiching region N of the heating belt 92 as an auxiliary means for peeling. The peeling member 70 is held by the holding member 72 in a state where the peeling claw 71 is close to the heating belt 92 in a direction (counter direction) opposite to the rotation direction of the heating belt 92.

  In addition, edge guides (not shown) are disposed at both ends of the holding member 95. The edge guides are arranged such that inner surfaces of both edge guides arranged so as to face each other at both end portions of the holding member 95 have a distance substantially matching the width of the heating belt 92. When the heating belt 92 rotates, movement of the heating belt 92 in the width direction (belt walk) is restricted by the end portions of the heating belt 92 coming into contact with the inner surfaces of both edge guides. Thus, the heating belt 92 is set so that the deviation is regulated by the edge guide.

  Then, the sheet K having the unfixed toner image is guided to the sandwiching area N of the fixing device 90 by the fixing entrance guide. When the paper K passes through the sandwiching area N, the toner image on the paper K is fixed by the pressure acting on the sandwiching area N and the heat supplied from the ceramic heater on the heating belt 92 side.

[Image forming apparatus]
Next, the image forming apparatus according to the present embodiment will be described.
FIG. 3 is a schematic configuration diagram showing the configuration of the image forming apparatus according to the present embodiment.
In the image forming apparatus according to the present embodiment, the fixing device according to the above-described embodiment is applied. The electrophotographic member according to the present embodiment may be applied as an intermediate transfer belt or a conveyance belt.

  As shown in FIG. 3, an image forming apparatus 100 according to this embodiment is an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of images in which toner images of respective color components are formed by an electrophotographic method. A primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15; A secondary transfer unit 20 that collectively transfers (secondary transfer) the superimposed toner image transferred onto the transfer belt 15 onto a sheet K as a recording medium, and a fixing device 60 that fixes the secondary transferred image onto the sheet K. And. Further, the image forming apparatus 100 includes a control unit 40 that controls the operation of each device (each unit).

  The fixing device 60 is the fixing device of the first embodiment described above, and the fixing device includes the pressure belt 62 of the present embodiment described above. The image forming apparatus 100 may be configured to include the fixing device 90 according to the second embodiment described above.

  Each of the image forming units 1Y, 1M, 1C, and 1K of the image forming apparatus 100 includes a photoconductor 11 that rotates in the arrow A direction as an example of an image holding body that holds a toner image formed on the surface.

  A charging device 12 for charging the photosensitive member 11 is provided around the photosensitive member 11 as an example of a charging unit for charging the surface of the image holding member. A latent image is formed on the surface of the image holding member charged by the charging unit. As an example of a latent image forming means for forming a laser beam, a laser exposure device 13 for writing an electrostatic latent image on the photosensitive member 11 (the exposure beam is indicated by Bm in the figure) is provided.

  Further, around the photosensitive member 11, each color component toner is accommodated as an example of a developing unit that forms a toner image by developing the latent image formed on the surface of the image holding member with the toner by the latent image forming unit. Then, a developing device 14 for visualizing the electrostatic latent image on the photoconductor 11 with toner is provided, and each color component toner image formed on the photoconductor 11 is transferred to the intermediate transfer belt 15 by the primary transfer unit 10. A primary transfer roll 16 for transferring is provided.

  Further, around the photoconductor 11, a photoconductor cleaner 17 for removing residual toner on the photoconductor 11 is provided, and a charger 12, a laser exposure device 13, a developing device 14, a primary transfer roll 16, and a photoconductor cleaner. Seventeen electrophotographic devices are sequentially arranged along the rotation direction of the photoconductor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Has been.

The intermediate transfer belt 15 which is an intermediate transfer member is constituted by a film-like pressure belt containing a resin such as polyimide or polyamide as a base layer and containing an appropriate amount of an antistatic agent such as carbon black. And the volume resistivity is formed so that it may become 10 < ⁶ > -10 < ¹⁴ > (omega | ohm) cm, The thickness is comprised by about 0.1 mm, for example.

  The intermediate transfer belt 15 is circulated and driven (rotated) at a predetermined speed in the direction B shown in FIG. 3 by various rolls. As these various rolls, a drive roll 31 that is driven by a motor (not shown) having excellent constant speed to rotate the intermediate transfer belt 15, and an intermediate transfer belt that extends substantially linearly along the arrangement direction of the respective photoreceptors 11. 15, a support roll 32 that supports the intermediate transfer belt 15, a tension applying roll 33 that functions as a correction roll that applies a constant tension to the intermediate transfer belt 15 and prevents the intermediate transfer belt 15 from meandering, and a back roll provided in the secondary transfer unit 20. 25. A cleaning back roll 34 is provided in a cleaning unit that scrapes off residual toner on the intermediate transfer belt 15.

The primary transfer unit 10 includes a primary transfer roll 16 that is disposed to face the photoconductor 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. Sponge layer is formed of blend rubber of NBR, SBR and EPDM mixed with a conducting agent such as carbon black, the volume resistivity is spongy cylindrical roll of 107.5-10 ^8.5 [Omega] cm.

  The primary transfer roll 16 is placed in pressure contact with the photoconductor 11 with the intermediate transfer belt 15 in between. Further, the primary transfer roll 16 has a voltage (primary polarity) opposite to the toner charging polarity (negative polarity; the same applies hereinafter). Transfer bias) is applied. As a result, the toner images on the respective photoconductors 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so that the superimposed toner images are formed on the intermediate transfer belt 15.

  The secondary transfer unit 20 is a secondary roller disposed on the toner image holding surface side of the intermediate transfer belt 15 as an example of a transfer unit that transfers the toner image formed by the back roll 25 and the developing unit to a recording medium. And a transfer roll 22.

The back roll 25 is made of a tube of EPDM and NBR blend rubber with carbon dispersed on the surface, and the inside is made of EPDM rubber. And it is formed so that the surface resistivity may be 10 ⁷ to 10 ¹⁰ Ω / □, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd., the same shall apply hereinafter). The back roll 25 is disposed on the back side of the intermediate transfer belt 15 to constitute a counter electrode of the secondary transfer roll 22, and a metal power supply roll 26 to which a secondary transfer bias is stably applied is disposed in contact. ing.

On the other hand, the secondary transfer roll 22 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 to 10 ^8.5 Ωcm.

  The secondary transfer roll 22 is placed in pressure contact with the back roll 25 with the intermediate transfer belt 15 in between. Further, the secondary transfer roll 22 is grounded and a secondary transfer bias is formed between the secondary transfer roll 22 and the back roll 25. The toner image is secondarily transferred onto the paper K conveyed to the transfer unit 20.

  Further, on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15, an intermediate transfer belt that removes residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer and cleans the surface of the intermediate transfer belt 15. A cleaner 35 is provided so as to be able to contact and separate.

  On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 that generates a reference signal serving as a reference for taking image forming timings in the image forming units 1Y, 1M, 1C, and 1K. It is arranged. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. Each image forming unit is instructed by an instruction from the control unit 40 based on the recognition of the reference signal. 1Y, 1M, 1C, and 1K are configured to start image formation.

  Further, in the image forming apparatus according to the present embodiment, as a transport unit that transports the paper K, the paper storage unit 50 that stores the paper K, and the paper K accumulated in the paper storage unit 50 is taken out and transported at a predetermined timing. A paper feed roll 51, a transport roll 52 that transports the paper K fed by the paper feed roll 51, a transport guide 53 that feeds the paper K transported by the transport roll 52 to the secondary transfer unit 20, and the secondary transfer roll 22. A conveyance belt 55 that conveys the sheet K conveyed after the secondary transfer to the fixing device 60 and a fixing entrance guide 56 that guides the sheet K to the fixing device 60 are provided.

Next, a basic image forming process of the image forming apparatus according to the present embodiment will be described.
In the image forming apparatus according to the present embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is subjected to predetermined image processing by an image processing device (not shown), and then image formation is performed. The image forming work is executed by the units 1Y, 1M, 1C, and 1K.

  The image processing apparatus performs predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing on the input reflectance data. Is given. The image data that has been subjected to image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates each of the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K with, for example, an exposure beam Bm emitted from a semiconductor laser in accordance with the input color material gradation data. . In each of the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K.

  The toner images formed on the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photoconductors 11 and the intermediate transfer belt 15 are in contact with each other. The More specifically, in the primary transfer portion 10, a voltage (primary transfer bias) having a polarity opposite to the toner charging polarity (minus polarity) is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, and the toner image. Are sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is transported to the secondary transfer unit 20, the transport unit rotates the paper feed roll 51 in accordance with the timing at which the toner image is transported to the secondary transfer unit 20. Paper K is supplied. The paper K supplied by the paper feed roll 51 is transported by the transport roll 52, and reaches the secondary transfer unit 20 through the transport guide 53. Before reaching the secondary transfer unit 20, the sheet K is temporarily stopped, and the registration roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner image is held. And the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the sheet K conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (negative polarity) is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back roll 25. Is done. The unfixed toner image held on the intermediate transfer belt 15 is collectively electrostatically transferred onto the paper K in the secondary transfer unit 20 pressed by the secondary transfer roll 22 and the back roll 25. The

  Thereafter, the sheet K on which the toner image has been electrostatically transferred is conveyed as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is conveyed downstream of the secondary transfer roll 22 in the sheet conveyance direction. It is conveyed to the belt 55. The transport belt 55 transports the paper K to the fixing device 60 in accordance with the optimal transport speed in the fixing device 60. The unfixed toner image on the paper K conveyed to the fixing device 60 is fixed on the paper K by receiving a fixing process with heat and pressure by the fixing device 60. Then, the sheet K on which the fixed image is formed is conveyed to a paper discharge container (not shown) provided in the discharge unit of the image forming apparatus.

  On the other hand, after the transfer to the paper K is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and is cleaned by the cleaning back roll 34 and the intermediate transfer belt cleaner 35. It is removed from the intermediate transfer belt 15.

  Although the embodiments of the present invention have been described above, the present invention is not construed as being limited to the above-described embodiments, and various modifications, changes, and improvements can be made, and a range that satisfies the requirements of the present invention. Needless to say, this is feasible.

  In the image forming apparatus according to the present embodiment, the electrophotographic image forming apparatus has been described. However, the image forming apparatus is not limited to this, and a known image forming apparatus other than the electrophotographic system (for example, an endless belt for paper conveyance is provided). Or an inkjet recording apparatus).

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

(Measurement of contact angle)
To measure the contact angle of the functional surface (outer peripheral surface) of the polyimide endless belt with pure water, use a surface contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd. The contact angle between the water droplet and the sample surface was measured from the side.

(Measurement of fluorine atom content)
The fluorine atom content of the functional surface (outer peripheral surface) of the polyimide endless belt was calculated as described above using an XPS apparatus.

(Evaluation)
Evaluation of the abrasion resistance of the polyimide endless belt against paper rubbing and the releasability from the toner was performed by the following method.
The obtained polyimide endless belt was set as a pressure belt on a Fuji Xerox DCC400 equipped with a heating roll / pressure belt type fixing device (see FIG. 1), and the following evaluation was performed. The results are shown in Table 1.

-Wear resistance of pressure belt-
The wear resistance of the pressure belt was evaluated as follows. The electrophotographic apparatus was set to have an 800 W halogen lamp heater inside the heating roll, a set temperature of 150 ° C., a speed of 150 mm / sec, and a nip width of 8 mm. As the toner, color toner (cyan) for DocuCenterColor400 manufactured by Fuji Xerox Co., Ltd. was used and fixed on “J paper” manufactured by Fuji Xerox Co., Ltd. Under the above conditions, 100,000 sheets (100 kpv) were tested, and the abrasion resistance was evaluated by measuring the thickness of the pressure belt after the test and calculating the amount of decrease per 1 kpv as the amount of wear. It was.

-Releasability of pressure belt-
Evaluation of releasability of the pressure belt was performed as follows. The conditions of the electrophotographic apparatus are the same as in the above-mentioned abrasion resistance evaluation. When the print sample passes 100 sheets with double-sided output and there is no occurrence of jamming (separation failure from the pressure belt), it is judged as good. The number of jams was evaluated.

Example 1
First, as a polyamic acid resin solution, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine are synthesized in N-methyl-2-pyrrolidone (NMP). A solution containing the obtained polyamic acid and having a solid content concentration of 18% (mass%, the same applies hereinafter) and a viscosity of 20 Pa · s was prepared.
Next, hexafluoroepoxypropane (manufactured by Daikin Industries) as a fluorine-containing epoxide was added to the polyamic acid resin solution so as to have a concentration of 10% with respect to the solid content of the polyamic acid resin solution, and stirred.
The polyamic acid resin solution thus obtained was applied to the surface of a cylindrical aluminum mold (cylindrical core) having an inner diameter of 30 mm and a length of 450 mm to form a coating film. In addition, the release property after belt molding was improved by previously applying a release agent to the surface of the cylindrical mold.
Next, the mold was dried at 100 ° C. for 60 minutes in a nitrogen gas atmosphere in a state where the mold was rotated in the cylindrical circumferential direction at 20 rpm.
After the drying process, the mold was placed in an oven and gradually heated to 350 ° C. in a nitrogen gas atmosphere to imidize. Stepwise heating was performed at 160 ° C. for 1 hour, 250 ° C. for 30 minutes, and 350 ° C. for 1 hour. Thereafter, the mold was allowed to cool at room temperature (25 ° C.), the resin was removed from the mold, and the target polyimide endless belt was obtained.
As a result of measuring the contact angle of the outer peripheral surface of the obtained polyimide endless belt with pure water, it was 108 degrees.
The fluorine atom content on the outer peripheral surface of the obtained polyimide endless belt was 35%.
As shown in Table 1, the wear resistance and releasability of the obtained polyimide endless belt were superior to those of the comparative examples, and excellent wear resistance and releasability were obtained.

(Example 2)
A polyamic acid resin solution was prepared in the same manner as in Example 1. To this polyamic acid resin solution, 3-perfluorohexyl-1,2-epoxypropane (produced by Daikin Industries) as a fluorine-containing epoxide was added. The solution was added to a solid content of 8% and stirred. An endless belt was produced in the same manner as in Example 1, and the contact angle with pure water on the outer peripheral surface was measured. As a result, it was 112 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 32%.
As shown in Table 1, the wear resistance and releasability of the obtained polyimide endless belt were superior to those of the comparative examples, and excellent wear resistance and releasability were obtained.

(Example 3)
A polyamic acid resin solution was prepared in the same manner as in Example 1. To this polyamic acid resin solution, 3-perfluorohexyl-1,2-epoxypropane (produced by Daikin Industries) as a fluorine-containing epoxide was added. The solution was added to a solid content of 40% and stirred. A polyimide endless belt was produced in the same manner as in Example 1, and the contact angle with pure water on the outer peripheral surface was measured and found to be 122 degrees.
The fluorine atom content on the outer peripheral surface of the obtained polyimide endless belt was 52%. This is a number larger than the fluorine atom weight in the total atomic weight of polyimide and fluorine-containing epoxide, but XPS is the outermost surface analysis, and the polyimide endless belt of this example is selectively dried in a hydrophobic atmosphere during firing. It is thought that it is gathered on a certain outermost surface.
As shown in Table 1, the wear resistance and releasability of the obtained polyimide endless belt were superior to those of the comparative examples, and excellent wear resistance and releasability were obtained.

(Comparative Example 1)
In the same manner as in Example 1, a polyamic acid resin solution was prepared, and a fluorine-containing epoxide was not added, and the same was applied to the surface of the cylindrical core as in Example 1 to form a coating film.
Next, the mold was dried at 100 ° C. for 60 minutes in a nitrogen gas atmosphere in a state where the mold was rotated in the cylinder circumferential direction at 20 rpm.
After the drying step, a PTFE aqueous paint (fluorine resin dispersion, solid content concentration 60%, viscosity 200 mPa · s) containing water as a solvent was prepared. This paint was uniformly applied by a spiral application method, and after application, the paint was dried in an airless drying oven at 80 ° C. for 10 minutes. After drying, it was imidized in an oven in the same manner as in Example 1. Thereafter, the mold was removed from the cylindrical mold to obtain a polyimide endless belt. As a result of measuring the contact angle of the endless belt surface with pure water, it was 135 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 76%.
As a result of evaluation of the wear resistance and releasability of the obtained polyimide endless belt, as shown in Table 1, the wear resistance was greatly reduced as compared with the Examples.

(Comparative Example 2)
Prepare a polyamic acid resin solution in the same manner as in Example 1, add no fluorine-containing epoxide, apply and imidize on the surface of the cylindrical core as in Example 1, and produce an endless belt as in Example 1. did. As a result of measuring the contact angle of the outer peripheral surface with pure water, it was 70 degrees.
The fluorine atom content on the outer peripheral surface of the obtained polyimide endless belt was 0%.
As a result of evaluation of the wear resistance and releasability of the obtained polyimide endless belt, as shown in Table 1, 100 sheets of jam occurred on the double-sided output paper.

(Comparative Example 3)
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as a tetracarboxylic dianhydride and 2,2-bis (4-aminophenyl) as a diamine compound in the polyamic acid resin solution of Example 1 A polyamic acid resin solution was prepared using hexafluoropropane, an endless belt was prepared in the same manner as in Example 1 without adding a fluorine-containing epoxide, and the contact angle with pure water on the outer peripheral surface was measured. It was a degree.
The fluorine atom content on the outer peripheral surface of the obtained polyimide endless belt was 15%.
As a result of the evaluation of the wear resistance and releasability of the obtained polyimide endless belt, as shown in Table 1, 45 sheets jam occurred when the double-sided output paper was passed.

Example 4
A polyamic acid resin solution was prepared in the same manner as in Example 1. To this polyamic acid resin solution, 3-perfluorohexyl-1,2-epoxypropane (produced by Daikin Industries) as a fluorine-containing epoxide was added. It added and stirred so that it might become a 50% density | concentration with respect to solid content. An endless belt was produced in the same manner as in Example 1, and the contact angle with pure water on the outer peripheral surface was measured and found to be 119 degrees.
The fluorine atom content on the outer peripheral surface of the obtained polyimide endless belt was 67%. The wear resistance and releasability of the obtained polyimide endless belt are as shown in Table 1, and the releasability was superior to that of the comparative example. However, the wear resistance was lower than that of Comparative Example 1.

(Example 5)
An endless belt was produced in the same manner as in Example 1 except that pyromellitic dianhydride and 4,4′-diaminodiphenylmethane were prepared as the polyamic acid resin solution. As a result of measuring the contact angle of the outer peripheral surface with pure water, it was 109 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 30%.
As shown in Table 2, the obtained polyimide endless belt had excellent wear resistance and releasability as compared with Comparative Example.

(Example 6)
A polyamic acid resin solution was prepared in the same manner as in Example 1. To this polyamic acid resin solution, 3-perfluorobutyl-1,2-epoxypropane as a fluorine-containing epoxide was added to the solid content of the polyamic acid resin solution. % Concentration was added and stirred. An endless belt was produced in the same manner as in Example 1, and the contact angle with pure water on the outer peripheral surface was measured. As a result, it was 114 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 32%.
As shown in Table 2, the obtained polyimide endless belt had excellent wear resistance and releasability as compared with Comparative Example.

(Comparative Example 4)
A polyamic acid resin solution was prepared in the same manner as in Example 1. To this polyamic acid resin solution, hexafluoroepoxypropane (produced by Daikin Industries) as a fluorine-containing epoxide was 2% of the solid content of the polyamic acid resin solution. Added to a concentration and stirred. An endless belt was produced in the same manner as in Example 1, and the contact angle with pure water on the outer peripheral surface was measured. As a result, it was 78 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 3.5%.
As shown in Table 2, the obtained polyimide endless belt had insufficient wear resistance and release properties.

(Example 7)
A polyamic acid resin solution was prepared in the same manner as in Example 1. In this polyamic acid resin solution, hexafluoroepoxypropane (produced by Daikin Industries) as a fluorine-containing epoxide was 5% of the solid content of the polyamic acid resin solution. Added to a concentration and stirred. An endless belt was produced in the same manner as in Example 1, and the contact angle with pure water on the outer peripheral surface was measured. As a result, it was 98 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 6%.
As shown in Table 2, the obtained polyimide endless belt had excellent wear resistance and releasability as compared with Comparative Example.

(Example 8)
A polyamic acid resin solution was prepared in the same manner as in Example 1. To this polyamic acid resin solution, hexafluoroepoxypropane (produced by Daikin Industries) as a fluorine-containing epoxide was 45% of the solid content of the polyamic acid resin solution. Added to a concentration and stirred. As a result of producing an endless belt in the same manner as in Example 1 and measuring the contact angle of the outer peripheral surface with pure water, it was 120 degrees.
The fluorine atom content of the outer peripheral surface of the obtained polyimide endless belt was 55%.
As shown in Table 2, the obtained polyimide endless belt had excellent wear resistance and releasability as compared with Comparative Example.

1Y, 1M, 1C, 1K Image forming unit 10 Primary transfer unit 11 Photoconductor 12 Charger 13 Laser exposure unit 14 Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Photoconductor mcleaner 20 Secondary transfer unit 22 Secondary transfer roll 25 Back roll 26 Power supply roll 31 Drive roll 32 Support roll 33 Tension applying roll 34 Cleaning back roll 35 Intermediate transfer belt cleaner 40 Control unit 42 Reference sensor 43 Image density sensor 50 Paper storage unit 51 Paper feed roll 52 Transport roll 53 Transport guide 55 Transport Belt 56 Fixing entrance guide 60 Fixing device 61 Heating roll 611 Core 612 Heat resistant elastic layer 613 Release layer 62 Pressure belt 63 Belt running guide 64a Front clamping member 64 Pressure pad 64b Peeling clamping member 65 Holding member 66 Halogen lamp 68 Sliding sheet 6 Temperature sensitive element 70 separating member 71 separation claw 72 holding member 80 the edge guide 82 ceramic heater 90 the fixing device 91 the pressure roll 911 core 912 heat-resistant elastic layer 913 release layer 92 heating belt 95 retaining member 100 an image forming apparatus

Claims (6)

A surface comprising a polyimide resin having a repeating structural unit represented by the following general formula (1) and having a structural unit represented by the following general formula (2) partially interposed between the structural units of the repeating structural unit A member for an image forming apparatus.

(In the general formulas (1) and (2), Ar represents a tetravalent organic group having one or more aromatic rings.
Y represents a divalent organic group.
R represents an organic group having a hydroxyl group.
X represents an organic group having a fluorine atom.
n represents an integer of 1 or more. )   The image forming apparatus member according to claim 1, wherein X in the general formula (2) represents an organic group having 3 to 20 fluorine atoms.   3. The member for an image forming apparatus according to claim 1, wherein a fluorine atom content measured by X-ray photoelectron spectroscopy on the surface of the layer containing the polyimide resin is 5% or more and 60% or less.   A member for an image forming apparatus, comprising a layer containing a polyimide resin obtained by imidizing a polyamic acid resin obtained by reacting an epoxy compound having a fluorine atom with some structural units of a repeating structural unit. A heating member, and a pressure member disposed in contact with the heating member,
5. A fixing device in which at least one of the heating member and the pressure member includes the image forming apparatus member according to claim 1. An image carrier,
Latent image forming means for forming a latent image on the surface of the image carrier;
Developing means for developing the latent image with toner to form a toner image;
Transfer means for transferring the toner image to a recording medium;
Fixing means for fixing the toner image to the recording medium;
With
The image forming apparatus according to claim 5, wherein the fixing unit is a fixing device.