JP2007086492A - Method for manufacturing semiconductive member and endless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductive member, whereby a semiconductive coating material for obtaining a semiconductive member having a desired electric resistance value is efficiently prepared, load on a manufacturing process is reduced, and the semiconductive member with uniform electric resistance value is stably obtained, and to provide an endless belt using the semiconductive member. <P>SOLUTION: The method for manufacturing the semiconductive member includes: a step of mixing a carbon black dispersion liquid containing carbon black dispersed in a resin solution and a viscosity adjustment liquid containing no carbon black, thereby obtaining the semiconductive coating material; and a step of applying the semiconductive coating material, thereby forming the semiconductive member. In the manufacturing method for the semiconductive member, the carbon black dispersion liquid is prepared by dispersing the carbon black in the resin solution with a viscosity of 1 to 20 Pa s, and the carbon black dispersion liquid and the viscosity adjustment liquid with viscosity higher than that of the resin solution are mixed to obtain the semiconductive coating material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a semiconductive member used in an electrophotographic image forming apparatus such as a copying machine or a printer, and an endless belt using the same, and more particularly to a semiconductive member having a desired resistance value. It relates to a method for obtaining efficiently.

  In an electrophotographic apparatus, a rotating body made of metal, resin, or rubber is used for a photosensitive member, a transfer member, a fixing member, etc., but the rotating body can be deformed for downsizing or high performance of the apparatus. In some cases, a resin belt having a small thickness is used. The material is preferably a polyimide (hereinafter abbreviated as “PI”) resin or a polyamideimide (hereinafter abbreviated as “PAI”) resin in terms of strength, dimensional stability, heat resistance and the like. . In this case, if there is a seam in the belt, a defect due to the seam occurs in the output image. Therefore, an endless belt without a seam is preferable.

  As a method for producing an endless belt, for example, there is a method in which a film-forming resin solution is applied to the surface of a cylindrical core, dried, heated and reacted as necessary, and then the resin film is peeled from the core ( For example, see Patent Document 1).

On the other hand, when an endless belt is used for a photoconductor or a transfer body, the semiconductive property is adjusted to a value in a predetermined semiconductive region (a volume resistivity range of about 10 ⁵ to 10 ¹¹ Ωcm). It is necessary to use a member. The semiconductive member is formed by applying a semiconductive paint adjusted to obtain the predetermined resistance value.

  Semi-conductive paint is made by dispersing carbon black that imparts conductivity to the film-forming resin solution, but it is manufactured with the same composition ratio due to the influence of lots of materials used and variations in conditions when carbon black is dispersed. Even so, the resistance values of the obtained members may not be the same. Further, when carbon black is not finely dispersed, there is a problem that the resistance value is uneven or fluctuates.

  That is, the adjustment of the resistance value of the semiconductive paint can be controlled mainly by the amount of carbon black added, but due to the above-mentioned variation, the amount of carbon black added is expected to be constant or adjusted and dispersed. The street resistance value may not be obtained. Such deviation of resistance and poor dispersion greatly affect the electrical characteristics of the semiconductive member, that is, the endless belt, leading to deterioration of image characteristics.

  When the film-forming resin is a PI resin, in order to adjust the resistance value, carbon black is dispersed in polyamic acid, which is a PI precursor, and carbon black is dispersed in advance in a solvent or a monomer solution and polymerized and dispersed. There is a way to make liquid.

Regarding the above method, acidic carbon having a DBP absorption amount of 40 cm ³ or more and 90 cm ³ or less and a volatile content per specific surface area of 100 m ² / g in a polyamic acid solution is 2.5% by mass or more using a disperser using media. Although it is described that black is finely dispersed (see, for example, Patent Document 2), it is not sufficient to obtain resistance maintenance stability. In addition, the disperser using the media has a large amount of about 20% by mass remaining in the media and the container, and also causes film defects due to impurities entering from the media and the container. There is a problem that it cannot be applied to a highly viscous solution because the medium is rotated at a high speed.

  Further, a method of polymerizing polyamic acid by adding an acid anhydride and diamine after carbon black is dispersed in a solvent has been proposed (see, for example, Patent Document 3). Since these various functional groups cause problems in the polyamic acid polymerization reaction, there is a problem that it is necessary to deactivate carbon black in advance.

  On the other hand, as a transfer member, a PI resin endless belt is disclosed which is prepared by dividing a mixed liquid of carbon black into two or more and colliding with a pressure of 150 MPa or more (see, for example, Patent Document 4). Dispersing carbon black with such a collision type disperser eliminates the problems of the disperser using the above media, but the viscosity of the solution suitable for dispersion and the viscosity of the solution suitable for coating are not necessarily limited. Since they are not equivalent, there was a problem that they could not be processed under optimal conditions.

Furthermore, even if the carbon black dispersion liquid is prepared by various dispersion methods as described above, since the dispersion state varies from dispersion lot to dispersion lot, the electrical resistance value of the formed semiconductive member also varies, and the resistance value is subtle. This has been a serious problem in the production of a semiconductive member for an endless belt that requires careful adjustment.
JP 2002-91027 A JP 2001-342344 A JP 2000-355432 A JP 2004-279531 A

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, according to the present invention, it is possible to efficiently prepare a semiconductive paint for obtaining a semiconductive member having a desired electric resistance value, to reduce the load on the manufacturing process, and to increase the electric resistance. It is an object of the present invention to provide a method for producing a semiconductive member capable of stably obtaining a semiconductive member having a uniform value and an endless belt using the same.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> A step of preparing a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a viscosity adjusting liquid not containing carbon black, and applying the semiconductive paint to make the semiconductor conductive Forming a member, and a method for producing a semiconductive member comprising:
Carbon black is dispersed in a resin solution having a viscosity in the range of 1 to 20 Pa · s to prepare the carbon black dispersion, and the carbon black dispersion is mixed with a viscosity adjusting liquid having a higher viscosity than the resin solution. It is a manufacturing method of the semiconductive member which produces a semiconductive paint.

<2> The method for producing a semiconductive member according to <1>, wherein the dispersion of the carbon black is performed by causing a carbon black mixed liquid divided into two or more to collide with a pressure of 150 MPa or more.

<3> A step of preparing a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a resistance adjusting liquid not containing carbon black, and applying the semiconductive paint to make the semiconductive Forming a member, and a method for producing a semiconductive member comprising:
Two or more kinds of test paints having different mixing ratios of the carbon black dispersion liquid and the viscosity adjusting liquid are prepared in advance, each of the resistance check members is molded using the test paint, and the resistance value of each of the resistance check members To the semiconductive member manufacturing method for determining the mixing ratio of the carbon black dispersion liquid and the resistance adjusting liquid in the semiconductive paint.

<4> A step of preparing a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a resistance adjusting liquid not containing carbon black, and applying the semiconductive paint to make the semiconductor conductive Forming a member, and a method for producing a semiconductive member comprising:
A prepared semi-conductive paint B and a semi-conductive paint A having a known resistance value as a semi-conductive member are mixed at a constant mixing ratio to prepare a mixed paint, and the resistance confirmation member is prepared using the mixed paint Is formed, and the mixing ratio of the carbon black dispersion liquid and the resistance adjusting liquid in the semiconductive coating material B is readjusted from the resistance value of the resistance confirmation member.

<5> An endless belt using a semiconductive member obtained by the method for producing a semiconductive member according to any one of <1> to <4>.

  According to the present invention, it is possible to efficiently prepare a semiconductive paint for obtaining a semiconductive member having a desired electric resistance value, to reduce the load on the manufacturing process, and to increase the electric resistance. It is possible to provide a method for producing a semiconductive member capable of stably obtaining a semiconductive member having a uniform value and an endless belt using the same.

Hereinafter, the present invention will be described in detail.
<Method for producing semiconductive member>
The first method for producing a semiconductive member of the present invention (hereinafter referred to as “first present invention”) includes a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a viscosity adjusting liquid not containing carbon black. A method for producing a semiconductive member, comprising: mixing to produce a semiconductive paint; and applying the semiconductive paint to form a semiconductive member, wherein the viscosity is 1 to 20 Pa. The carbon black dispersion is prepared by dispersing carbon black in a resin solution in the range of s, and the semiconductive paint is prepared by mixing the carbon black dispersion and a viscosity adjusting liquid having a higher viscosity than the resin solution. It is characterized by producing.

  The second semiconductive member manufacturing method of the present invention (hereinafter referred to as “second present invention”) includes the same steps as the first manufacturing method, and the carbon black dispersion liquid is previously prepared. And two or more kinds of test paints having different mixing ratios of the resistance adjusting liquid not containing carbon black, each resistance confirmation member is molded using the test paint, and the surface resistivity of each of the resistance confirmation members is The mixing ratio of the carbon black dispersion liquid and the resistance adjusting liquid in the semiconductive paint is determined.

  Furthermore, the third method for producing a semiconductive member of the present invention (hereinafter referred to as “third invention”) includes the same steps as the first method for producing the semiconductive member produced in advance. A mixed paint by mixing the conductive paint B and the semiconductive paint A having a known surface resistivity as a semiconductive member at a constant mixing ratio, and forming a resistance confirmation member using the mixed paint, The mixing ratio of the carbon black dispersion liquid and the resistance adjustment liquid not containing carbon black in the semiconductive paint B is readjusted from the surface resistivity of the resistance confirmation member.

  When a semiconductive member is formed from a semiconductive paint, a semiconductive paint in which carbon black is dispersed is used. However, as described above, it is difficult to finely disperse carbon black in a resin solution. As a result, the dispersion state tends to vary from dispersion to dispersion. Therefore, even if a semiconductive paint is prepared with the same composition, the resistance value of the formed semiconductive member is not constant, and a semiconductive member having a uniform resistance value can be manufactured stably and efficiently. There wasn't. In particular, when preparing a dispersion using a high viscosity resin solution having a viscosity of 21 Pa · s or more, dispersion becomes more difficult, and the above problem becomes remarkable.

The inventors of the present invention have prepared a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed and a viscosity adjusting liquid not containing carbon black, and further, a dispersion state of the carbon black dispersion liquid. It has been found that the above-mentioned problems can be solved by examining the method for determining the mixing ratio of the carbon black dispersion liquid and the viscosity adjusting liquid.
Hereinafter, the first to third aspects of the present invention will be described.

(First invention)
As described above, the method for producing a semiconductive member according to the first aspect of the present invention includes a step of producing a semiconductive paint by mixing a carbon black dispersion and a viscosity adjusting liquid, and the semiconductive paint. And a step of forming a semiconductive member by coating. In the first aspect of the present invention, the carbon black dispersion is prepared by dispersing using a resin solution having a viscosity in the range of 1 to 20 Pa · s, and a viscosity adjusting solution having a viscosity higher than that of the resin solution is prepared. A semiconductive paint is produced by mixing.

  Thus, the dispersion of the carbon black into the resin solution is not performed in a high viscosity state close to the final semiconductive paint, but in a relatively low viscosity state suitable for the dispersion of the carbon black, and then By mixing a viscosity adjusting liquid having a higher viscosity to obtain a semiconductive coating material, a dispersion liquid having a smaller dispersed particle diameter of carbon black and a uniform particle diameter can be obtained.

  In addition, since the carbon black dispersion liquid has a uniform and stable dispersion state, there is less variation in resistance value among the dispersion lots, and even when mixed with the viscosity adjusting liquid, the carbon black dispersion liquid has a substantially constant mixing ratio. A semiconductive member having a resistance value can be obtained. Furthermore, since the liquid properties (dispersion state, viscosity, etc.) after production are stable, there is little change in resistance for each member during production, and there is no need to adjust the coating conditions.

-Semi-conductive paint manufacturing process-
First, the carbon black dispersion in the present invention will be described.
The carbon black dispersion is prepared by mixing a predetermined amount of carbon black in a resin solution and dispersing it with a disperser. Although it does not restrict | limit especially as resin used for a resin solution, From thermoplastic resins, such as a polyimide resin, an epoxy resin, an acrylic resin, a silicone resin, a polyester resin, a polycarbonate resin, a polyamide resin, a polyamide-imide resin, a thermosetting resin, etc. You can choose.

Among these, PI resin and PAI resin are particularly preferable in terms of ensuring the strength and flexibility as an endless belt.
In the present invention, a resin solution is prepared by dissolving the various resins in a solvent. The resin solution is not only a solution in which a high molecular weight resin is dissolved, but also a polyimide precursor solution to be described later. In addition, a solution of a resin precursor that reacts to become a resin is also included.

Here, the resin solution using PI resin and PAI resin which are preferable resin is explained in full detail.
PI resin is obtained by heating the precursor. The polyamic acid solution that is a PI precursor is synthesized from an anhydride of tetracarboxylic acid and a diamine. Examples of the tetracarboxylic acid anhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and mixtures thereof. Examples of the diamine include, for example, para Examples include phenylenediamine and 4,4′-diaminodiphenyl ether.

  In particular, polyamic acid composed of biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether, polyamic acid composed of biphenyltetracarboxylic dianhydride and paraphenylenediamine, pyromellitic dianhydride and 4,4 Polyamic acid composed of '-diaminodiphenyl ether is preferable because it can satisfy various properties as an endless belt such as film strength.

  On the other hand, PAI resins are acid anhydrides such as trimellitic anhydride, ethylene glycol bisanhydro trimellitate, propylene glycol bisanhydro trimellitate, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, 3, It can be obtained by combining 3 ′, 4,4′-biphenyltetracarboxylic acid anhydride and the like with the diamine and performing a polycondensation reaction in an equimolar amount. The PAI resin is preferably 100% imidized.

  In the precursor solution (resin solution), the above components are dissolved in an aprotic polar solvent such as N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide, acetamide, N, N-dimethylformamide and the like. It is prepared with. In addition, selection of the mixing ratio of the precursor in the case of this preparation is performed by adjusting suitably.

In the first aspect of the present invention, the resin solution has a viscosity of 1 to 20 Pa · s. By setting the viscosity of the resin solution within this range, the viscosity at the time of dispersion of the carbon black can be set to an appropriate range for dispersion, and the target dispersion state can be reached in a short time.
When the viscosity is less than 1 Pa · s, the Brownian motion of the carbon black is likely to occur, and therefore reaggregation due to particle bonding is likely to occur. Also, when the viscosity exceeds 20 Pa · s, the fluidity of the solution decreases, so the pressure during dispersion must be further increased, or more time is required for dispersion, and the number of passes is reduced. I have to increase it.

  The viscosity of the resin solution is preferably in the range of 1 to 18 Pa · s, and more preferably in the range of 2 to 15 Pa · s. The resin solution has a viscosity of 25 ° C., 55 ° C. under conditions of 5 rpm using a conical plate type viscometer (manufactured by Toki Sangyo Co., Ltd., model RE80U) using a rotor: 3 ° × R14. It was measured under the measurement environment of% RH. The same applies to the following viscosities.

  Although the density | concentration of a resin solution is suitably selected so that it may become the said viscosity range, the solid content concentration of a preferable solution is 10-40 mass%, More preferably, it is the range of 12-30 mass%.

  As the carbon black, those having a pH of 5 or less and a volatile content of 3.5% by mass or more can be preferably used, and examples thereof include general carbon blacks such as oil furnace black and channel black. From the viewpoint of properties, those obtained by oxidizing carbon black are preferable. Moreover, it is also possible to mix | blend multiple types instead of one type.

  The amount of carbon black to be mixed is not particularly limited as long as it can be dispersed. However, since the dispersion work described later takes time and effort, the carbon black is dispersed at as high a concentration as possible during dispersion. It is preferable to increase the amount by adding a resin solution (viscosity adjusting liquid or the like) after dispersion to adjust the content to a predetermined carbon black. Therefore, the mixing amount of carbon black at the time of dispersion is preferably in the range of 40 to 120 parts by mass, more preferably in the range of 50 to 100 parts by mass with respect to 100 parts by mass of the film-forming resin.

  The dispersion of carbon black can be performed by various methods used for ordinary coating preparation, for example, a method using a ball mill, a sand mill, a paint shaker or the like. However, unless carbon black is uniformly and finely dispersed, a semiconductive member having desired resistance characteristics and excellent surface resistivity maintenance property cannot be obtained.

From the above viewpoint, in the present invention, the number average particle diameter of carbon black after dispersion is preferably 500 nm or less, and more preferably 400 nm or less. When the number average particle diameter of carbon black is larger than 500 nm, the mechanical strength of the semiconductive member after molding may be lowered, and the amount of change in surface resistivity may be increased.
In addition, the number average particle diameter of carbon black can be measured using, for example, a dynamic light scattering type measuring device PAR-III manufactured by Otsuka Electronics. The measurement conditions are: clock rate: 100 μs, accumulate time: 10 times, correlate ch: 128, temperature: 20 ° C., solvent: N-methylpyrrolodon.

Hereinafter, as a method for uniformly and finely dispersing carbon black in the first aspect of the present invention, a preferred example will be described.
In the present invention, it is preferable to use a collision type disperser that does not use media as a dispersion method. The collision type disperser is a disperser that collides and disperses two or more divided solutions. As the solution, a carbon black mixed solution obtained by mixing a resin solution and carbon black is used.

  In order to disperse, carbon black is first mixed with the resin solution, and preliminary dispersion is performed. Pre-dispersion is to stir the carbon black mixture well with a stirrer to loosen the carbon black mass finely. Next, the preliminarily dispersed carbon black mixed liquid is passed through a collision type disperser.

  FIG. 1 is an explanatory view schematically showing the principle of a collision-type disperser, in which two first flow path pipes 50 connected at one point from upstream to downstream of a liquid flow indicated by arrows, and a connecting portion Is dispersed by flowing a carbon black mixed liquid in a flow path constituted by a connection pipe 52 constituting the first pipe and a second flow path pipe 54 branched into two or more from one end of the connection pipe 52.

  In the operation, first, the carbon black mixed solution is caused to flow through the two first flow path tubes 50 respectively. The fluid pressure is set to a certain level or more, and the solutions collide with each other in the vicinity of one end 52a of the connecting pipe 52 constituting the connecting portion. The collided liquid mixture passes through the connecting pipe 52 and flows into the second flow path pipe 54 branched into two or more, and is divided into two again. The mixed liquid divided into two parts can be further passed through the first flow path pipe 50, and the mixing / division can be repeated two or more times. In this way, by mixing and mixing the mixed liquid, it becomes possible to add a collision force with a strong pressure together with a shearing force to the carbon black mixed liquid, and uniformly and finely disperse the carbon black at a high concentration. Can do.

  The flow pressure is preferably 150 MPa or more, more preferably in the range of 150 to 250 MPa, and even more preferably in the range of 180 to 220 MPa. If the flow pressure is less than 150 MPa, carbon black may not be finely dispersed.

The mixed liquid that has collided passes through the connecting pipe 52, but the connecting part of the two first flow path pipes 50 (in the vicinity of one end 52a of the connecting pipe 52 in the figure), that is, the collision part where the two solutions collide. the minimum cross-sectional area of 0.07 mm ² or less (preferably 0.007～0.05Mm ² or less, more preferably 0.015~0.04mm ²⁾ preferably with. This is because the pressure can be efficiently applied to the mixed liquid by reducing the area where the mixed liquid collides. Here, the minimum cross-sectional area of the collision portion where the two solutions collide corresponds to the cross-sectional area of the flow channel pipe 50 in the vicinity of the inlet of the connecting pipe 52 in the drawing.

  Examples of the collision type disperser include “Geanus PY” manufactured by Genus, “Ultimizer” manufactured by Sugino Machine, “Nanomizer” manufactured by Nanomizer, and the like.

The dispersion time depends on the total amount of carbon black mixed liquid to be dispersed. For example, in order to disperse 100 L of carbon black mixed liquid to a preferable dispersion state with a flow pressure of 200 Pa · s, it may be dispersed for about 5 to 10 hours. preferable.
In addition, the solution viscosity after dispersion | distribution rises from the viscosity before dispersion | distribution by adding the finely disperse | distributed carbon black, and may be 3-30 Pa.s.

  Further, when there are impurities mixed in or carbon black aggregates during dispersion, coarse particles are removed by passing the solution through, for example, a filter having an aperture of 25 μm or less to obtain a carbon black dispersion in a uniform dispersion state. Is possible.

  Next, a viscosity adjusting liquid is added to and mixed with the obtained carbon black dispersion to prepare a semiconductive paint. The viscosity adjusting liquid increases the viscosity of the carbon black dispersion prepared at a low viscosity to disperse the carbon black up to the viscosity of the coating liquid used for actual coating, and at the same time, carbon black (P) and resin (B For the purpose of adjusting the P / B ratio. Therefore, a solution containing the same resin as that used for the resin solution is usually used.

  In the first aspect of the present invention, a solution having a higher viscosity than the resin solution used for the carbon black dispersion is used as the viscosity adjusting liquid. Specifically, it is preferable to have a viscosity of about 5 to 100 times the viscosity of the resin solution, and more specifically, the viscosity is preferably in the range of 50 to 1000 Pa · s, and is preferably 100 to 500 Pa · s. It is more preferable to set the range.

  If the viscosity of the viscosity adjusting liquid is lower than 50 Pa · s, the effect of increasing the viscosity of the carbon black dispersion may be small. If the viscosity is higher than 1000 Pa · s, the work when mixing with the carbon black dispersion is difficult. There is a case.

  As a combination of the viscosity of the resin solution and the viscosity adjusting liquid as described above, when the viscosity of the low viscosity resin solution is in the range of 1 to 20 Pa · s, the viscosity of the high viscosity adjusting liquid is 50 to 1000 Pa ·. The range of s is preferable. The mass ratio A / B of the mixed liquid amount A of the carbon black dispersion and the mixed liquid amount B of the viscosity adjusting liquid is preferably in the range of 1/5 to 5/1.

  In this way, carbon black is dispersed at a high concentration, and then a high viscosity solution is added to adjust the carbon black content, thereby reducing the amount of liquid during dispersion and improving the efficiency of the dispersion work. Can do.

  In consideration of the electric resistance value required for the semiconductive member for an endless belt used in the image forming apparatus described later, the carbon black content after mixing is 100 parts by mass of the resin for film formation. On the other hand, it is preferably in the range of 22 to 33 parts by mass, and more preferably in the range of 24 to 32 parts by mass.

  When the content of carbon black is less than 22 parts by mass, for example, when a semiconductive member is used as a transfer member, the resistance may increase and the toner may not be transferred. On the other hand, when it exceeds 33 parts by mass, the resistance becomes too low and the film becomes brittle and the flexibility may be lowered.

  Mixing of the carbon black dispersion and the viscosity adjusting liquid can be carried out under normal mixing conditions using a stirrer or the like used for normal liquid mixing. Considering the stability of carbon black dispersion, it is preferable to gradually add a predetermined amount of the viscosity adjusting liquid while stirring the carbon black dispersion.

  The viscosity of the semiconductive paint after mixing is preferably 5 to 100 Pa · s, and more preferably 10 to 50 Pa · s. Specifically, it is preferable to use a coating material having a solid content including resin and carbon black in the range of 20 to 40% by mass.

-Semiconductive member molding process-
In this step, the produced semiconductive paint is applied to a substrate such as a metal and dried, heat treated, etc., if necessary, to form a semiconductive member.
In the following, description will be given by taking an example of forming an endless belt in which the semiconductive member of the present invention is preferably used.

  First, the semiconductive paint is applied to the surface of a substrate such as a cylindrical core to form a coating film. As this coating method, there are a dip coating method and an annular coating method, but it is preferable to use an annular coating method in which the film thickness is adjusted using an annular body.

  The substrate is preferably a cylindrical core made of metal such as aluminum, stainless steel, or nickel. The length of the cylindrical core is required to be equal to or longer than the target endless belt, and when a plurality of endless belts are manufactured at the same time, a length equal to or more than the number is required. Further, in order to secure a margin for the invalid area generated at the end, it is desirable that the length is about 10 to 40% longer than the target length.

  The outer diameter of the cylindrical core body is adjusted to the diameter of the target endless belt, and the thickness is set to a thickness that can maintain the strength of the core body. In order to prevent the formed film from adhering to the surface of the cylindrical core body, the surface of the cylindrical core body is given releasability. For this purpose, the surface of the core body is covered with a fluororesin or a silicone resin. There is a method of applying a release agent to the surface.

  In the case of the PI resin, there is evaporation of residual solvent and water generated during the reaction at the time of imidation, and the film after the reaction may partially swell, particularly when the film thickness exceeds 50 μm. It is. In order to prevent this swelling, it is preferable to roughen the core surface as disclosed in JP-A-2002-160239. As the method, there are methods such as blasting, cutting, sandpaper peeling, etc., and the surface roughness is preferably about 0.2 to 2 μm in terms of arithmetic average roughness Ra. Thereby, the gas generated from the film can go out through a slight gap formed between the core and the film, and does not swell.

Next, an example of an annular coating method using the annular body will be described.
FIG. 2 is a schematic cross-sectional view of the coating apparatus during coating. However, only the main part of the application is shown, and the peripheral part such as the lifting / lowering means of the cylindrical core is omitted. In the present specification, “applying onto the cylindrical core” means that the coating liquid is applied onto the surface of the cylindrical core and, when the surface has a layer, the layer. Further, “rising the cylindrical core” is a relative relationship with the liquid level, and includes the case of “stopping the cylindrical core and lowering the coating liquid level”.

  In FIG. 2, when a solution (semi-conductive paint) 2 is put into an annular coating tank 7 and passed through the cylindrical core 1 from the lower part to the upper part, a coating film 4 is formed and coating is performed. Under the cylindrical core body 1, another cylindrical core body 1 ′ is overlaid. A sealing material 8 is attached to the bottom of the annular coating tank 7 so that the solution 2 does not leak. The sealing material 8 is made of a flexible plate material such as polyethylene, silicone rubber, or fluorine resin. On the liquid surface of the coating liquid 2, an annular body 5 having a circular hole 6 larger than the outer peripheral outer diameter of the axial cross section of the cylindrical core body 1 is installed in a freely movable state. The annular body 5 floats on the solution 2 during application, but if the buoyancy is insufficient at rest, the legs and arms that support the annular body 5 are provided on the outer peripheral surface of the annular body 5 or the application tank to prevent sinking. May be.

  At the time of application, the film thickness of the coating film 4 is adjusted by the gap between the cylindrical core body 1 and the circular hole 6, so the gap is adjusted in view of the desired coating film thickness. The rising speed of the cylindrical core body 1 is preferably about 0.1 to 1.5 m / min. When the cylindrical core body 1 is lifted through the circular hole 6, the cylindrical core body 1 is interposed by the solution 2. A frictional resistance is generated in the gap between the annular body 5 and the annular body 5 is lifted. When the annular body 5 is lifted in this way, the annular body 5 moves in the horizontal direction so that the frictional resistance with the cylindrical core body 1 is constant in the circumferential direction, and the gap is constant in the circumferential direction. Therefore, the annular body 5 does not come into contact with the cylindrical core body 1 and a constant gap is always maintained.

  The viscosity of the solution to which this coating method can be applied is in the range of 1 to 1000 Pa · s, but the viscosity of the solution suitable for coating the endless belt coating solution is in the range of 5 to 100 Pa · s. Therefore, as described above, the carbon black dispersion liquid in the present invention is prepared as a semiconductive paint by adding a viscosity adjusting liquid so as to increase the viscosity in accordance with the adjustment of the carbon black content.

  After the application to the cylindrical core 1, the coating film 4 is dried to remove the solvent. The drying conditions are preferably set so that the residual solvent contained in the coated film after drying is about 30 to 50% by mass, the temperature is in the range of 100 to 200 ° C., and the time is preferably about 10 to 60 minutes. In order to accelerate the drying of the solvent, hot air may be blown onto the surface of the coating film. When drying, the axial direction of the cylindrical core 1 is preferably horizontal and rotated at 2 to 20 rpm so that the coating film does not hang downward.

  Next, the cylindrical core body 1 is heated to form a film. When the film-forming resin is a PI resin, the heating temperature is generally in the range of 250 to 400 ° C, preferably in the range of 300 to 350 ° C. On the other hand, when the film-forming resin is a PAI resin, there is no reaction, but in order to completely dry the residual solvent, it is usually heated in the range of 220 to 320 ° C, preferably in the range of 250 to 300 ° C.

  Regarding the heating temperature of the PI resin, the imidation reaction of the PI resin mainly composed of biphenyltetracarboxylic dianhydride as an acid component is difficult to complete unless it is placed at a temperature of 250 ° C. or higher for a certain period of time. The imidization is almost completed when the temperature is kept for 2 hours or more. When time is less than 2 hours, imidation is inadequate and various characteristics are not fully exhibited.

  On the other hand, the bending resistance of the PI resin is improved when heated at a temperature of 300 ° C. or higher for 1 hour or longer. Therefore, combining the above two conditions and heating to a temperature of 250 ° C. for 2 hours or more and at a temperature of 300 ° C. or more for 1 hour or more completes imidation of the PI resin and obtains necessary bending resistance. Therefore, this is a preferable condition.

  The heating conditions will be specifically described with reference to the graph shown in FIG. The horizontal axis in FIG. 11 is time, and the vertical axis is the temperature of the core body. The temperature of the core body increases with time and then decreases. The core temperature on the vertical axis is a value obtained by measuring the actual temperature, and can be said to indicate the same temperature as the PI film, but the set temperature of the heating furnace and the furnace atmosphere temperature may be higher than this.

  In the figure, Condition A is an example in which the temperature is raised from room temperature to 300 ° C. in 2 hours, held at 300 ° C. for 1 hour and 20 minutes, and cooled to room temperature in 1 hour and 40 minutes. Condition B is from room temperature to 250 ° C. In this example, the temperature was raised in 1 hour, then raised from 250 ° C. to 300 ° C. in 30 minutes, held at 300 ° C. for 1 hour, and cooled to room temperature over 1 hour and 40 minutes. Further, the condition C is raised from room temperature to 250 ° C. over 30 minutes, held at 250 ° C. for 30 minutes, then raised from 250 ° C. to 300 ° C. over 20 minutes, held at 300 ° C. for 1 hour, and held at room temperature for 1 hour 30 This is an example of cooling over a minute.

  The heating conditions may be any of the above conditions. However, since the temperature of condition b was quickly raised to 250 ° C., the total time required was shorter than condition i, and condition c was further shorter than condition b. However, if it is heated too rapidly up to 250 ° C., not only will the temperature unevenness increase, but the residual solvent in the film may become foamed, so there is a limit. Moreover, when the heat capacity of the core is large, it may be difficult to heat rapidly.

  Note that the time at which the temperature is set to 250 ° C. includes the time in the cooling process after the temperature is set to 300 ° C. or higher. Specifically, in condition i, it is placed at 250 ° C. for 2 hours and 300 ° C. for 1 hour and 20 minutes as indicated by the dotted auxiliary line, and in condition b, it is placed at 250 ° C. for 2 hours and 300 ° C. for 1 hour, In Condition C, it is placed at 250 ° C. for 2 hours and 15 minutes and at 300 ° C. for 1 hour. In addition to various heating conditions, the present invention is required to be placed at a temperature of 250 ° C. for 2 hours or more and at a temperature of 300 ° C. or more for 1 hour or more.

  On the other hand, a time exceeding 4 hours as the temperature at 250 ° C. is unnecessary because it is not only inefficient as a manufacturing time but also may deteriorate the resin. In addition, it is not necessary to leave it at a temperature of 300 ° C. or more for more than 2 hours because it is inefficient and wastes heat energy. Furthermore, as the upper limit of the temperature, a temperature of 400 ° C. or higher is not preferable because the rigidity of the PI resin becomes too high and the bending resistance may be lowered. When the diamine component is a PI resin other than paraphenylenediamine, it is more preferable that the upper limit of the temperature is 350 ° C. or less.

  On the other hand, imidation tends to cause variation in reaction rate due to temperature unevenness during heating. In general, it is known that PI resin shrinks during imidation, but if there is a variation in reaction rate, the degree of shrinkage also varies, which is not preferable because it causes variations in film thickness and mechanical properties. . In particular, when conductive particles such as carbon black are dispersed in the PI resin, the resistance value tends to vary. When an endless belt is used as a transfer belt, a large variation in resistance value is not preferable because the density of the transferred image becomes uneven.

  In order to reduce the temperature unevenness, it is better not to apply hot air directly to the core surface when the PI precursor film after solvent drying is heated. As the method, for example, a heating furnace is preferably used that blows hot air from above. It is also preferable that the hot air does not hit the surface of the core body through the inside of the core body.

  In a heating furnace in which hot air is blown out from the side surface, for example, as shown in FIG. 13, there is a method in which a cylindrical core body 30 is covered with a cover 32 and placed in the heating furnace. In this case, the gap between the cylindrical core body 30 and the cover 32 is preferably about 20 to 100 mm. Even if hot air enters the gap, it does not hit the film strongly, so there may be such a gap. Heat transfer to the cylindrical core body 30 is performed not only by hot air entering the inside of the cylindrical core body 30 but also by radiant heat from heating the cover 32.

  After cooling, the cylindrical core is taken out, and the formed film (semiconductive member) is peeled from the core to obtain an endless belt. The endless belt may be cut to a predetermined length by cutting an unnecessary portion of the end, and may be subjected to drilling or ribbing as necessary.

When the semiconductive member in the present invention is formed into an endless belt used for a transfer belt or the like, the thickness is preferably in the range of 75 to 85 μm.
Further, the preferable surface resistivity is in the range of 1 × 10 ⁸ Ω / □ to 1 × 10 ¹⁵ Ω / □, more preferably in the range of 1 × 10 ¹⁰ Ω / □ to 1 × 10 ¹³ Ω / □, and more preferably. Is in the range of 1 × 10 ¹¹ Ω / □ to 1 × 10 ¹² Ω / □.

On the other hand, the preferred volume resistivity is in the range of 1 × 10 ⁶ Ω · cm to 1 × 10 ¹³ Ω · cm, more preferably in the range of 1 × 10 ⁸ Ω · cm to 1 × 10 ¹² Ω · cm, More preferably, it is in the range of 1 × 10 ⁹ Ω · cm to 1 × 10 ¹¹ Ω · cm.
If the surface resistivity or volume resistivity is too low, for example, when used as a transfer member, the current may flow too much during transfer and the transferred image may be disturbed. On the other hand, if the surface resistivity or volume resistivity is too high, Transfer may not be possible because no current flows.

  Further, according to the production method of the present invention, carbon black can be contained in the resin uniformly and finely, so when used as a transfer belt, the amount of change in surface resistivity before and after use of the semiconductive member ( The common logarithm value) can be within ± 0.8 logΩ, and the maintainability is excellent. If the amount of change (common logarithm) exceeds ± 0.8 logΩ, density unevenness may occur during transfer.

  The amount of change in surface resistivity is a value obtained when the surface resistivity value is expressed as a common logarithm, and the surface resistivity value before use is subtracted from the surface resistivity value after use. Moreover, before and after use means before and after being subjected to image output for about 1 hour under an applied voltage condition of about 100 to 1000V.

  For the surface resistivity, a circular electrode shown in FIG. 3 (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.) is used, and a voltage of 100 V is applied at 22 ° C. and 55% RH according to JIS K6911. The value obtained from the current value after 10 seconds. FIG. 3 is a schematic plan view (a) and a schematic cross-sectional view (b) showing an example of a circular electrode. The circular electrode includes a first voltage application electrode A and a plate-like insulator B. The first voltage application electrode A has a columnar electrode portion C and a cylindrical ring electrode having an inner diameter larger than the outer diameter of the columnar electrode portion C and surrounding the columnar electrode portion C at regular intervals. Part D is provided.

A test piece T is sandwiched between the cylindrical electrode part C and the ring-shaped electrode part D and the plate-like insulator B in the first voltage application electrode A, and the cylindrical electrode part C and the ring shape in the first voltage application electrode A. The current I (A) flowing when the voltage V (V) is applied between the electrode part D is measured, and the surface resistivity ρs (Ω / □) can be calculated by the following formula (1). Here, in the following formula (1), d (mm) indicates the outer diameter of the cylindrical electrode portion C, and D (mm) indicates the inner diameter of the ring-shaped electrode portion D.
ρs = π × (D + d) / (D−d) × (V / I) (1)

  In addition, the volume resistivity is determined by applying a voltage of 100 V at 22 ° C. and 55% RH in accordance with JIS K6911 using a circular electrode shown in FIG. 4 (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). The value obtained from the current value after 30 seconds. FIG. 4 is a schematic plan view (a) and a schematic cross-sectional view (b) illustrating an example of a circular electrode, and the circular electrode includes a first voltage application electrode A ′ and a second voltage application electrode B ′. The first voltage application electrode A ′ has a cylindrical electrode part C ′ and a cylindrical shape having an inner diameter larger than the outer diameter of the cylindrical electrode part C ′ and surrounding the cylindrical electrode part C ′ at a constant interval. Ring-shaped electrode portion D ′.

A test piece T is sandwiched between the cylindrical electrode portion C ′ and the ring-shaped electrode portion D ′ of the first voltage application electrode A ′ and the second voltage application electrode B ′, and the cylindrical shape of the first voltage application electrode A ′. The current I (A) that flows when the voltage V (V) is applied between the electrode portion C ′ and the second voltage application electrode B ′ is measured, and the volume resistance of the transfer member T ′ is calculated by the following equation (2). The rate ρv (Ωcm) can be calculated. Here, in the following formula (2), t represents the thickness of the transfer member T ′.
ρv = 19.6 × (V / I) × t (2)

(Second invention)
The method for producing a semiconductive member according to the second aspect of the present invention includes the same steps as in the first aspect of the present invention, and in the step of producing a semiconductive paint, the carbon black dispersion liquid and carbon black are included in advance. Two or more kinds of test paints having different mixing ratios of resistance adjusting liquids are prepared, and resistance check members are molded using the test paints, and carbon in the semiconductive paint is determined from the resistance values of the resistance check members. The mixing ratio of the black dispersion liquid and the resistance adjusting liquid is determined.
Here, the resistance value of the resistance confirmation member means either surface resistivity or volume resistivity. The same applies hereinafter.

  As described above, when a semiconductive member is manufactured using a semiconductive paint containing carbon black, the paint has the same composition ratio due to the influence of the lot of materials used in the paint and the variation in conditions when carbon black is dispersed. However, the resistance values of the obtained members are not almost the same. This is a serious problem when a semiconductive member is manufactured as a member that requires precise resistance control, such as a transfer member.

  Therefore, in the second aspect of the present invention, carbon black is previously dispersed at a high concentration to prepare a carbon black dispersion, and this is mixed with a resin solution not containing carbon black (resistance adjusting solution), and the mixing ratio is mixed. Two or more kinds of semiconductive paints having different from each other are prepared, a resistance confirmation member is molded for each, a resistance value is obtained, and a carbon black dispersion liquid and a resistance adjusting liquid for obtaining a desired resistance value from these resistance values; It has been found that a semiconductive member having a constant resistance value can be obtained with high accuracy by determining the mixing ratio.

  In this method, a semiconductive sample is formed using a carbon black dispersion dispersed at a high concentration in advance, and the mixing ratio of the carbon black dispersion and the resistance adjusting liquid not containing carbon black is determined from the resistance value. However, the error is reduced. The reason is that the sample using the carbon black dispersion dispersed at a high concentration finally shows a resistance value that is lower than the desired resistance value as a semiconductive member. This is because determining the mixing ratio with the resistance adjusting liquid increases the error.

-Semi-conductive paint manufacturing process-
Preferred materials used for the carbon black dispersion and resistance adjusting liquid in the second invention are the same as those preferably used for the carbon black dispersion and viscosity adjusting liquid described in the first invention, respectively. The same applies to the ratio of resin to carbon black in the carbon black dispersion.

  However, in the second aspect of the present invention, the viscosity of the resistance adjusting liquid is not necessarily higher than the viscosity of the resin solution for preparing the carbon black dispersion, and the resistance adjusting liquid and the resin solution have the same viscosity. There may be. However, as described in the first aspect of the present invention, it is preferable to carry out the dispersion at a low viscosity for the dispersion of carbon black, so that the viscosity of the resin solution is preferably lower than the viscosity of the resistance adjusting liquid (in this case, The resistance adjusting liquid in the second invention and the viscosity adjusting liquid in the first invention are functionally the same).

  Specifically, the viscosity of the resin solution is preferably in the range of 1 to 20 Pa · s, and the viscosity of the resistance adjusting liquid is preferably in the range of 50 to 1000 Pa · s. At this time, the solid content concentration of the resin solution is preferably in the range of 10 to 40% by mass, and the solid content concentration of the resistance adjusting liquid is preferably in the range of 10 to 40% by mass. Further, the dispersion of the carbon black is not particularly limited, but it is preferably performed using the collision type disperser described in the first aspect of the present invention.

In the second aspect of the present invention, the mixing ratio of the carbon black paint and the resistance adjusting liquid in the semiconductive paint is determined from the surface resistivity of the resistance confirmation member using, for example, two or more kinds of test paints.
That is, since the carbon black content in the paint and the surface resistivity of the member molded from the paint are in a proportional relationship, as shown in the relationship between the mixing ratio of the resistance adjusting liquid and the surface resistivity of the member in FIG. The relationship between the mixing ratio of the resistance adjusting liquid and the surface resistivity of the member is also proportional. Therefore, the optimum mixing ratio R can be determined by proportional calculation by adjusting the test paints having arbitrary mixing ratios P and Q so as to straddle the desired resistance value and confirming the surface resistivity as those members.

  In addition, although the method for determining the mixing ratio has been described based on the surface resistivity, it can be similarly performed by confirming the volume resistivity.

  When two or more kinds of test paints having different mixing ratios are prepared and a resistance confirmation member is molded for each, the target semiconductive member itself can be used as the resistance confirmation member, but the resistance values can be correlated. For example, a test piece smaller than the target member can be used, which is preferable for reducing the amount of paint used during sample preparation and ease of operation.

  When the test piece has a plate shape, the test paint can be applied by a simple method using a wire bar, a scraping blade, or a bar. Specifically, as shown in FIG. 6, for example, an adhesive tape 12 having a certain thickness is attached on a substrate 10 such as a metal so as to form a required test piece shape, and a liquid pool is collected at the end. The test paint 16 arranged as follows is spread in the direction of the arrow by the scraping bar 14 to produce a test coating film.

  FIG. 7 shows this state when viewed from the left side of FIG. FIG. 7A shows a state immediately before the coating film is formed, but the test paint 16 arranged at the left end of the substrate 10 is spread by sliding the scraping bar 14 in the arrow direction. As a result, as shown in the cross-sectional view of FIG. 7B, the portion surrounded by the adhesive tape 12 having a certain thickness (height) is filled with the test paint having a certain thickness. Finally, as shown in FIG. 7C, when the adhesive tape 14 is peeled off, a test coating film having a certain thickness is formed on the substrate 10. Then, if this is heated as it is, a test piece for resistance confirmation can be obtained.

By producing a test piece by such a method, a test piece of a constant size and thickness can always be easily obtained, and variations in resistance values as resistance confirmation members can be reduced. .
The area of the test piece is preferably about 50 mm × 200 mm, and the thickness is preferably about 2 to 10 mm.

On the other hand, a cylindrical test piece is also preferable to match an actual endless belt even if the size is smaller than a plate-like test piece.
In the case of a cylindrical test piece, as a simple coating method, as shown in FIG. 8, a method is used in which a cylindrical substrate 20 such as a metal to which a test paint 26 is attached is rotated and a scraping bar is pressed against the cylindrical substrate 20 for coating. Can be adopted. At that time, in order to obtain a desired film thickness, for example, a pressure-sensitive adhesive tape 22 having a desired thickness is wound around both ends of the surface of the cylindrical base body 20 so as to have a step from the surface of the cylindrical base body 20, and the test solution 26 is provided in the gap. It is preferable that the cylindrical substrate 20 is rotated and pressed with a scraping bar to scrape off.

  When this state is viewed from the left side of FIG. 8, it is as shown in FIG. FIG. 9A shows a state in which the scraping bar 24 is pressed against the rotating columnar base 20, but the test paint 26 adhered to the columnar base 20 has a certain film thickness when the scraping bar 24 is pressed. It is spread over a thick film (adhesive tape is omitted in the figure). As a result, as shown in FIG. 9B, the portion surrounded by the adhesive tape 12 having a certain thickness (height) is filled with the test paint having a certain thickness. Finally, as shown in FIG. 7C, if the adhesive tape 24 is peeled off, a test coating film having a certain thickness is formed on the cylindrical substrate 20. Then, if this is heated as it is, a test piece for resistance confirmation can be obtained.

By producing a test piece by such a method, a test piece having a constant thickness can be easily obtained under the same conditions as in actual endless belt manufacturing, and variation in resistance value as a resistance confirmation member. Can be reduced.
In this case, the cylindrical substrate 20 preferably has an outer diameter of 30 to 80 mm, a length of 100 to 500 mm, and a test piece thickness of about 1 to 5 mm.

In order to accurately correlate the resistance values, if the heat treatment of the test coating film for resistance confirmation is not performed under the same conditions as those of an actual endless belt or the like, an error may be caused. Therefore, by subjecting the substrate 10 or the cylindrical substrate 20 to which a test paint is applied, a heat treatment such as drying and firing under the same conditions as the step of forming the semiconductive member of the product, the resistance can be surely matched. Is preferable.
As the same conditions as the step of forming the semiconductive member, the conditions exemplified as the heat treatment conditions of the endless belt in the first invention are preferable.

-Semiconductive member molding process-
The details of the process of forming the semiconductive member using the semiconductive paint produced as described above are the same as those described in the first aspect of the present invention. The semiconductive member manufactured according to the second aspect of the present invention is precisely controlled to have a desired resistance value within the above-described preferable surface resistivity and volume resistivity ranges. If the carbon black dispersion liquid prepared in this way is used, it can be manufactured with a small amount of change in surface resistivity before and after use.

(Third invention)
The method for producing a semiconductive member according to the third aspect of the present invention includes the same steps as in the first aspect of the present invention. In the step of producing the semiconductive paint, the semiconductive paint B and the semiconductive material produced in advance are produced. A semi-conductive paint A having a known surface resistivity as a conductive member is mixed at a constant mixing ratio to produce a mixed paint, a resistance check member is formed using the mixed paint, and a resistance value of the resistance check member From the above, the mixing ratio of the carbon black dispersion liquid and the resistance adjusting liquid in the semiconductive paint B is readjusted.

  The third aspect of the present invention is a process for producing a semiconductive member using a semiconductive paint. For example, when a lot is switched from a semiconductive paint A that is already in use to the next semiconductive paint B, This is a useful method for fine adjustment of the resistance of the molded member. That is, when the semi-conductive paint B of the next lot is prepared with the same charging composition as the semi-conductive paint A of the previous lot, as described above, the lot of the material used for the paint and the conditions when dispersing the carbon black Even if a paint is produced with the same composition ratio due to the influence of variation, the resistance value of the obtained member is almost the same, so the resistance value of the member molded from the semiconductive paint of the next lot is the same as the previous lot. It will deviate from the resistance value of the member molded from the semiconductive paint.

  In order to avoid this problem, as in the second aspect of the present invention, the surface resistivity of the member obtained from two or more kinds of test paints using the carbon black dispersion liquid and the resistance adjusting liquid also for the semiconductive paint B of the next lot. It is sufficient to determine the mixing ratio of the carbon black dispersion and the resistance adjusting liquid from the above, but it is complicated to prepare a plurality of resistance confirmation members one by one in a continuous manufacturing process and to mix the semiconductive paint. There is also.

  Therefore, in the third aspect of the present invention, even if a semiconductive paint is prepared with the same composition of the carbon black dispersion and the resistance adjusting liquid for each lot, another lot is prepared using the semiconductive paint A in use. It has been found that by estimating the resistance value when the member of the semiconductive paint B is used, the resistance value between blending lots can be finely adjusted (readjusted) with a minimum number of man-hours.

-Semi-conductive paint manufacturing process-
Preferred materials used for the carbon black dispersion and the resistance adjusting liquid in the third aspect of the present invention are the same as those preferably used for the carbon black dispersion and the viscosity adjusting liquid described in the first aspect of the present invention. The same applies to the ratio of resin to carbon black in the carbon black dispersion.

  However, also in the third aspect of the present invention, as in the case of the second aspect of the present invention, it is not always necessary to make the viscosity of the resistance adjusting liquid higher than the viscosity of the resin solution for preparing the carbon black dispersion. Therefore, the preferred viscosity range and the preferred solid content concentration range of the resin solution and resistance adjusting solution used in the third invention are the same as the contents described in the second invention in the more preferred carbon black dispersion method. .

  In the third aspect of the present invention, for example, a semiconductive paint B is prepared with the same composition as the semiconductive paint A which is the preceding use lot, and a semiconductive paint A having a known resistance value as a member is used. The blending of the semiconductive paint B is readjusted so that the resistance value as a member is equivalent to that of the semiconductive paint A.

This will be specifically described with reference to the drawings.
FIG. 10 is a diagram schematically showing the surface resistivity of the molded member for each paint. In the figure, the surface resistivity [rho _A member according semiconductive coating material A are known are within the desired upper and lower limits. On the other hand, if the surface resistivity as a member of the semiconductive coating material B is ρ _B (it is unknown because it has not been confirmed), this value is out of the upper limit value, so readjustment is necessary.

In order to obtain the unknown surface resistivity ρ _B , for example, a semi-conductive paint A and a semi-conductive paint B are mixed at a mass ratio of 1/1 to prepare a mixed paint, and a resistance confirmation member is formed from the mixed paint The surface resistivity ρ _{A + B} is obtained. Accordingly, when the mixing amount of the semiconductive paint A in the mixed paint is a and the mixing amount of the semiconductive paint B is b, the surface resistivity ρ _B as a member of the semiconductive paint _B is expressed by the following formula ( It is obtained from 3).
ρ _B = {ρ _{A + B} × (a + b) / b} − {ρ _A × a / b} (3)

If ρ _B is obtained, the mixing ratio of the carbon black dispersion liquid and the resistance adjusting liquid in the semiconductive coating material B is known. Therefore, by adjusting the mixing ratio to make ρ _B equal to ρ _A , the semiconductivity can be obtained. The surface resistivity of the conductive paint member can be set to ρ _{B ′} which is within the upper and lower limit values. According to this method, the mixing ratio of the semiconductive coating material B of the next lot can be adjusted only by producing one resistance confirmation member.

  The method for adjusting the mixing ratio has been described based on the surface resistivity, but it can be similarly performed by confirming the volume resistivity.

  The confirmation of the resistance value may be performed on an endless belt as an actual product without producing a test piece, or may be carried out by similarly producing the test piece described in the second aspect of the present invention.

-Semiconductive member molding process-
The details of the process of forming the semiconductive member using the semiconductive paint produced as described above are the same as those described in the first aspect of the present invention. The semiconductive member manufactured according to the third aspect of the present invention is precisely controlled to a desired resistance value within the above-described preferable surface resistivity and volume resistivity ranges. If the carbon black dispersion liquid prepared in this way is used, it can be manufactured with a small amount of change in surface resistivity before and after use.

<Endless belt>
The endless belt of the present invention is formed using a semiconductive member produced by the above manufacturing methods. The preferred material constituting the endless belt and the preferred production method are as described above. The thickness of the endless belt is preferably in the range of 75 to 85 μm.

  Since the endless belt of the present invention uses the semiconductive member produced by each of the above manufacturing methods, the endless belt can always be obtained as having a resistance value within a desired range. Further, as described above, a semiconductive member having excellent carbon black dispersibility can also be obtained, so that even an endless belt has little change in resistance value and variation in resistance value before and after use.

  In addition, the semiconductive member made of PI resin, which is mainly composed of biphenyltetracarboxylic dianhydride as an acid component and is heat-treated under the above-mentioned preferable conditions, ensures a bending resistance of 1000 times or more by the MIT test. As a result, the endless belt produced in this way is strong against breakage.

  The film thickness can be measured with a dial gauge or an eddy current film thickness meter, etc., and the bending resistance by the MIT test can be measured with an off-the-shelf MIT tester (for example, manufactured by Ueshima Seisakusho or Toyo Seiki Seisakusho). . Usually, since there is a large error in the measurement of the number of bending resistances by the MIT test, in the present invention, 10 or more test pieces are taken from the endless belt, the number of bending resistances is measured, and the average value is 1000 times or more. Is a requirement. Furthermore, it is preferable that all the measured values are 1000 times or more.

When the endless belt of the present invention is used as a transfer belt, the resistance value is preferably about 10 ⁷ to 10 ¹³ Ωcm in terms of volume resistivity and about 10 ⁸ to 10 ¹³ Ω / □ in terms of surface resistivity. It is preferable to be within a range of one digit or less with respect to the center value. In the method for producing a semiconductive member of the present invention, the semiconductive member can be easily controlled to a desired resistance value within the above resistance range.

  In addition, as described above, a material heated by reducing the temperature unevenness at the time of imidization is preferable because the number of bending resistances and the resistance value unevenness are small.

  In order to produce a fixing belt from the endless belt of the present invention, a non-adhesive film is formed on the resin surface in order to prevent toner adhesion. Examples of non-adhesive materials include fluorine resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene / hexafluoropropylene copolymer (FEP). Is preferred. 5-50 micrometers is preferable and, as for the thickness of a fluororesin layer, 10-45 micrometers is more preferable.

  In order to form the fluororesin layer, it is preferable to apply a method in which the aqueous dispersion is applied and baked. As a coating method, the core body on which the PI precursor film is formed is dipped in a fluororesin dispersion and then raised to form a fluororesin coating film. It is preferable in terms of uniformity.

  After application, the solvent is dried and the fluororesin is baked. During the firing, the imidation treatment of the PI precursor film may be performed simultaneously.

  When the endless belt of the present invention is applied to a photoreceptor, a conductive layer is provided on the surface of the endless belt, and if necessary, an undercoat layer is formed, and then a photosensitive layer is formed. As the photosensitive layer, there are a single layer type and a laminated type in which a charge generation layer (CGL) and a charge transport layer (CTL) are functionally separated.

CGL is applied by dispersing a phthalocyanine pigment, a bisazo pigment, a trisazo pigment or the like in a binder resin such as polyvinyl butyral, polyester, or acrylic.
The CTL is applied by mixing a charge transport agent such as a hydrazone compound, a stilbene compound, a benzidine compound, a butadiene compound, or a triphenylamine compound with a binder resin such as polycarbonate, polyarylate, polymethyl methacrylate, or polyester.
The film thickness of CGL is generally about 0.05 to 1 μm, and the film thickness of CTL is generally about 15 to 40 μm. Each of the above layers may be formed by an annular coating method or other known methods. When forming each layer, as disclosed in Japanese Patent Application Laid-Open No. 2003-337434, it is preferable to apply each layer without removing the endless belt on the core, and remove it from the core after all the layers are formed.

Hereinafter, the present invention will be described more specifically with reference to examples.
<Measurement method for each characteristic>
First, the characteristic measurement method used in the following examples etc. will be described.
(Number average particle size of carbon black)
In each example, the dispersion obtained by dispersing carbon black in a polyamic acid varnish was measured using a dynamic light scattering type measuring device PAR-III manufactured by Otsuka Electronics. The measurement conditions are: clock rate: 100 μs, accumulate time: 10 times, correlate ch: 128, temperature: 20 ° C., solvent: NMP. The median value of the number-based average particle size at this time was defined as the number-average particle size.

(Surface resistivity)
The surface resistivity was measured using the circular electrode shown in FIG. 3 (HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd., outer diameter of cylindrical electrode portion C: 16 mm, inner diameter of ring electrode portion D: 30 mm, outer (Diameter: 40 mm), a voltage of 100 V was applied, and the current value after 10 seconds was calculated.

(Volume resistivity)
The volume resistivity is measured using the circular electrode shown in FIG. 4 (HR probe of HI-Lester IP manufactured by Mitsubishi Yuka Co., Ltd., outer diameter of the cylindrical electrode portion C: 16 mm, inner diameter of the ring-shaped electrode portion D: 30 mm, outer Diameter: 40 mm), a voltage of 100 V was applied, and a current value after 30 seconds was obtained and calculated.

[Test Example for First Invention]
<Example 1-1>
Low-viscosity varnish (NMP solution of polyamic acid containing equimolar amounts of biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether, solid fraction after imide conversion is 18% by mass, viscosity is 5 Pa · s) Carbon black (Degussa, Special Black 4, pH: 3, volatile content: 14% by mass) was added to 14.4 parts by mass and mixed to obtain a carbon black mixed solution. The carbon black mixed solution was collided after being divided into two at a pressure of 200 MPa using a Genus PY, the minimum cross-sectional area of the collision part of 0.032 mm ² , and dispersed again by passing through the path divided into two again. The time required for dispersion was 12 hours. Next, the mixture was filtered using a stainless sintered filter having an opening of 25 μm to remove coarse particles and obtain a carbon black dispersion. The yield of the dispersion was 93%.

In 100 parts by mass of the above carbon black dispersion, NMP solution of polyamic acid containing equimolar amounts of high-viscosity varnish (biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether), the solid fraction after imide conversion is 150 mass parts of 18 mass% and a viscosity of 140 Pa.s) were added, and it stirred for 30 minutes in the pressure reduction state using the planetary mixer. After stirring, vacuum degassing was performed for 2 hours to obtain a semiconductive paint having a viscosity of 46 Pa · s.
The properties of this semiconductive paint are shown in Table 1.

  Separately, an aluminum cylinder having an outer diameter of 366 mm, a wall thickness of 10 mm, and a length of 450 mm was prepared, and the surface was roughened to 1.0 μm with an arithmetic average roughness Ra by blasting. Next, a silicone release agent (trade name: Sepacoat, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the cylinder to obtain a cylindrical core.

  In the annular coating apparatus shown in FIG. 2, a rigid polyethylene having a thickness of 0.5 mm having an inner diameter of 386 mm and a bottom surface of the bottom surface of the annular coating tank 7 having an inner diameter of 500 mm and an inner height of 80 mm and an inner diameter of 362 mm. An annular sealing material 8 made of was attached. On the side surface of the annular coating tank 7, six supply ports to which a fluororesin tube having an inner diameter of 9 mm is attached at a position 20 mm from the bottom are installed at 60 ° intervals.

  As the annular body 5, an aluminum body having an outer diameter of 420 mm, an inner diameter of 367.1 mm at the smallest part of the circular hole 6 and a height of 50 mm was produced. The inner wall was linearly inclined, and the inclination angle with respect to the vertical line was 7 °. A portion parallel to the cylindrical core was formed at the upper end by 2 mm, and the roundness of the inner diameter was 8 μm.

  After the cylindrical core body 1 is passed through the center of the annular coating device and the annular body 5 is arranged, the semiconductive paint is injected into the annular coating tank 7 at a pressure of 0.5 MPa from a pressurized container (not shown). did. After the coating material filled the annular coating tank 7, the injection of the coating material was stopped when the liquid level reached 50 mm. Next, another cylindrical core body 1 ′ was placed under the cylindrical core body 1 and applied by pushing up at about 0.8 m / min. At that time, the annular body 5 was lifted by about 20 mm. Thereby, the PI precursor coating film 4 having a wet film thickness of about 500 μm was formed on the cylindrical core body 1.

  After the application, the cylindrical core body 1 was leveled and heated at 80 ° C. for 20 minutes and at 130 ° C. for 30 minutes while rotating at 6 rpm to dry the PI precursor coating film. As a result, a PI precursor film having a thickness of about 150 μm was obtained. Next, the cylindrical core body 1 was made vertical and placed in a heating device, and reacted by heating at 200 ° C. for 30 minutes and at 320 ° C. for 30 minutes to form a cylindrical PI resin film (semiconductive member).

  After cooling to room temperature, the film was extracted from the cylindrical core 1 to obtain an endless belt using the semiconductive member. Table 1 summarizes the initial surface resistivity and volume resistivity of the endless belt.

The obtained PI resin endless belt was incorporated in a color laser printer DocuPrint C2220 (made by Fuji Xerox Co., Ltd.) as a transfer belt, and 30000 copies were made using A4 vertical size paper in an environment of 10 ° C. and 15% RH. After copying the sheet, measure the surface resistivity of the endless belt where the paper did not pass by the method described above, and subtract the surface resistivity after the test from the surface resistivity before the test. Logarithmic value) was obtained.
The results are shown in Table 1. Note that if this amount of change (common logarithm value) exceeds ± 0.8 logΩ, density unevenness occurs during transfer.

<Example 1-2>
Low-viscosity varnish (NMP solution of polyamic acid containing equimolar amounts of biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether, solid fraction after imide conversion is 18% by mass, viscosity is 20 Pa · s) 100 11.2 parts by mass of carbon black (Degussa Special Black 4, pH: 3, volatile content: 14% by mass) is added to parts by mass, and the collision type disperser “Geanus PY”, the minimum cross-sectional area of the collision part. 0.032 mm < ² >", the pressure was 200 MPa, the solution was divided into two and then collided, and then again passed through the path divided into two and dispersed five times. The time required for dispersion was 12 hours. Next, the mixture was filtered using a stainless sintered filter having an opening of 25 μm to remove coarse particles, and a carbon black dispersion was obtained.

  In 100 parts by mass of the above carbon black dispersion, NMP solution of polyamic acid containing equimolar amounts of high-viscosity varnish (biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether), the solid fraction after imide conversion is 18 parts by mass and a viscosity of 80 Pa · s) were added, and the mixture was stirred for 30 minutes under reduced pressure using a planetary mixer. After stirring, vacuum degassing was performed for 2 hours to obtain a semiconductive paint having a viscosity of 49 Pa · s.

  Using this semiconductive paint, an endless belt was produced in the same manner as in Example 1, and the same evaluation was performed. Table 1 summarizes the characteristics of the semiconductive paint, the initial resistance value of the endless belt, and the amount of change in surface resistivity (common logarithm).

<Comparative Example 1-1>
Low-viscosity varnish (NMP solution of polyamic acid containing equimolar amounts of biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether, solid fraction after imide conversion is 18% by mass, viscosity is 35 Pa · s) 100 5.6 parts by mass of carbon black (Degussa Special Black 4, pH: 3, volatile content: 14% by mass) is added to parts by mass, and the collision-type disperser “Geanus PY, minimum cross-sectional area of collision part” 0.032 mm < ² >", the pressure was 200 MPa, the solution was divided into two and then collided, and then again passed through the path divided into two and dispersed five times. The time required for dispersion was 14 hours. Next, the mixture was filtered using a stainless sintered filter having an opening of 25 μm to remove coarse particles, and a carbon black dispersion was obtained.

Using this carbon black dispersion as it was as a coating solution, an endless belt was produced in the same manner as in Example 1, and the same evaluation was performed.
Table 1 summarizes the characteristics of the carbon black dispersion, the initial resistance value of the endless belt, and the amount of change in surface resistivity (common logarithm).

<Comparative Example 1-2>
Low-viscosity varnish (NMP solution of polyamic acid containing equimolar amounts of biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether, solid fraction after imide conversion is 18% by mass, viscosity is 35 Pa · s) 100 11.2 parts by mass of carbon black (Degussa Special Black 4, pH: 3, volatile content: 14% by mass) is added to parts by mass, and the collision type disperser “Geanus PY”, the minimum cross-sectional area of the collision part. 0.032 mm < ² >", the pressure was 200 MPa, the solution was divided into two and then collided, and then again passed through the path divided into two and dispersed five times. The time required for dispersion was 35 hours. Subsequently, it filtered using the stainless sintered filter with an opening of 25 micrometers, the coarse particle thing was removed, and the carbon black dispersion liquid was obtained.

  An NMP solution of polyamic acid containing equimolar amounts of high-viscosity varnish (biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether) in 100 parts by mass of the carbon black dispersion, and the solid fraction after imide conversion is 18 100 parts by mass of a mass% and a viscosity of 35 Pa · s) were added, and the mixture was stirred for 30 minutes under reduced pressure using a planetary mixer. After stirring, vacuum degassing was performed for 2 hours to obtain a semiconductive paint having a viscosity of 46 Pa · s.

Using this semiconductive paint, an endless belt was produced in the same manner as in Example 1, and the same evaluation was performed.
Table 1 summarizes the characteristics of the semiconductive paint, the initial resistance value of the endless belt, and the amount of change in surface resistivity.

<Example 1-3>
Using the same low-viscosity varnish and carbon black as used in Example 1, 100 parts by mass of low-viscosity varnish and 14 parts by mass of carbon black were added to a horizontal sand mill (Dynomill, Dynomill KDL) with a diameter of 2 mm. The zirconia beads were filled with about 60% by volume of the inner volume, and dispersion was carried out by passing the stirring blade having a diameter of 90 mm at a rotation speed of 1592 rpm five times. The dispersion time was 12 hours. Next, the mixture was filtered using a stainless sintered filter having an opening of 25 μm to remove coarse particles, and a carbon black dispersion was obtained. The yield of the dispersion was 78%.

  An NMP solution of polyamic acid containing equimolar amounts of high-viscosity varnish (biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether) in 100 parts by mass of the carbon black dispersion, and the solid fraction after imide conversion is 18 150 parts by mass of a mass% and a viscosity of 140 Pa · s) were added, and the mixture was stirred for 30 minutes under reduced pressure using a planetary mixer. After stirring, vacuum degassing was performed for 2 hours to obtain a semiconductive paint having a viscosity of 47 Pa · s.

Using this semiconductive paint, an endless belt was produced in the same manner as in Example 1, and the same evaluation was performed.
Table 1 summarizes the characteristics of the semiconductive paint, the initial resistance value of the endless belt, and the amount of change in surface resistivity (common logarithm). In Table 1, “dispersion time” is calculated as the dispersion time per 100 parts by mass of the final coating material. CB is an abbreviation for carbon black.

  As shown in Table 1, the semiconductive paint produced in the examples had good dispersibility of carbon black, and the amount of change in surface resistivity before and after use was small. On the other hand, in the comparative example, the dispersibility of the carbon black was slightly poor, and as a result, the stability of the surface resistivity was also deteriorated.

[Test Example for Second Invention]
<Example 2-1>
First, a carbon black dispersion was prepared in the same manner as in Example 1-1. In 100 parts by mass of this carbon black dispersion, varnish containing no carbon black as a resistance adjusting liquid (an NMP solution of polyamic acid containing equimolar amounts of biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether) Thereafter, the solid content ratio was 18% by mass and the viscosity was 140 Pa · s) at a mixing ratio of 141.9 parts by mass and 156.2 parts by mass, respectively, and defoamed to prepare two types of test paints.

  As shown in FIG. 6, an adhesive tape 12 having a thickness of about 500 μm was stretched around an aluminum plate having a thickness of 10 mm and a size of 150 mm × 150 mm, and a scraper bar 14 made of SUS304 having a diameter of 8 mm was disposed at the end. Next, a liquid pool of the test paint 16 is formed near the scraping bar 14, and the scraping bar 14 is slowly slid in the direction of the arrow, so that two coating films each having a wet film thickness of about 500 μm are provided for each paint. Formed. These were dried in a continuous dryer at 165 ° C. for 22 minutes, and then placed in a heating device and reacted by heating at 320 ° C. for 30 minutes to produce a PI resin resistance confirmation member.

When this PI resin film was peeled off from the plate and the surface resistivity was measured, the members mixed with 141.9 parts by mass of the resistance adjusting liquid were 2.14 × 10 ¹⁰ Ω / □ and 2.51 × 10 ¹⁰ Ω / □. Yes, 156.2 parts by mass of the mixed member was 2.24 × 10 ¹¹ Ω / □, 2.75 × 10 ¹¹ logΩ / □. From these results, when the mixing ratio of the resistance adjusting solution at which the desired resistance value was 6.31 × 10 ¹⁰ Ω / □ was calculated by the least square method, it was 147.7 parts by mass.

Based on the above results, 147.7 parts by mass of the resistance adjusting liquid was added to 100 parts by mass of the carbon black dispersion, and the mixture was stirred for 30 minutes under reduced pressure using a planetary mixer, and then vacuum-released for 2 hours. Foamed to obtain a semiconductive paint.
Using this semiconductive paint, a cylindrical semiconductive member was prepared in the same manner as in Example 1-1, and after cooling to room temperature, the coating was extracted from the cylindrical core to obtain an endless belt. Twenty endless belts were produced from the same coating solution by this method, and the average surface resistivity was determined.

The above-described preparation of the carbon black dispersion, determination of the mixing ratio of the resistance adjusting liquid, preparation of endless belts, and measurement of their surface resistivity were repeated a total of 5 times.
Table 2 summarizes the results of the determined mixing ratio and the average value of the surface resistivity of the semiconductive member.

<Comparative Example 2-1>
In Example 2-1, without preparing a resistance confirmation member for producing a semiconductive paint, an average of five dispersions in Example 2-1 was applied to the resistance adjusting solution with respect to 100 parts by mass of the carbon black dispersion. A coating material was prepared at a mixing ratio of 144.0 parts by mass, and an endless belt was prepared in the same manner, and the surface resistivity was measured.
The same processes from carbon black dispersion to endless belt production and surface resistivity measurement were repeated a total of 5 times. Table 3 summarizes the results of the average values of the surface resistivity of the respective semiconductive members.

  As shown in the results of Table 2, it can be seen that in the examples, the belt resistance variation between lots using the coating liquid of 5 dispersion lots is small. On the other hand, in the comparative example shown in Table 3, it can be seen that the surface resistivity varies considerably after five dispersions.

[Test Example for Third Invention]
<Example 3-1>
First, as the semiconductive paint A, the first dispersion paint of Example 2-1 was prepared. As described above, the average value of the surface resistivity when this paint member is used is 5.82 × 10 ¹⁰ Ω / □. Next, a semiconductive paint B was prepared in the same manner as in Example 2-1, with the blending ratio of the resistance adjusting liquid set to 147.7 parts by mass. In order to know the resistance value of the semiconductive paint B as a member, the following examination was performed.

100 parts by mass of the semiconductive paint A and 100 parts by mass of the semiconductive paint B were mixed to prepare a mixed paint, and two resistance confirmation members were molded using this paint in the same manner as in Example 2-1. The average value of the surface resistivity ρ _{A + B} of this resistance confirmation member was 6.07 × 10 ¹⁰ Ω / □. From the value of ρ _{A + B} , the surface resistivity ρ _B of the member made of the semiconductive paint B is obtained using the above formula (3), and is 6.31 × 10 ¹⁰ Ω / □.

From this ρ _B value, the mixing ratio in the semiconductive paint B ′ in which the surface resistivity as the member is equivalent to the surface resistivity as the member of the semiconductive paint A (of the resistance adjusting liquid with respect to 100 parts by mass of the carbon black dispersion liquid) Amount) was estimated to be 147.0 parts by weight.

From this result, for the semiconductive paint B whose mixing ratio is known, the mixing ratio was readjusted to 147.0 parts by mass using the carbon black dispersion and / or the resistance adjusting liquid, and the same as in Example 2-1. Thus, 20 endless belts were produced. Then, it was determined the average value of the surface resistivity was ^{10 Ω} / □ 5.82 × ^10.
Thus, by using the semiconductive paint A, the mixing ratio of the semiconductive paint B can be adjusted by a simple method so that the resistance value of the member is equivalent to the known semiconductive paint A. It was.

<Reference Example 1>
An aluminum tube having an outer diameter of 30 mm and a length of 400 mm was prepared as the core, and the surface was roughened to Ra: 0.3 μm by blasting with spherical alumina particles. A silicone release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface, and baked at 250 ° C. for 1 hour. Next, as shown in FIG. 2, the core body 1 was passed through the annular coating tank 7, and another core body 1 ′ was attached below the core body 1.

  As a PI precursor, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and paraphenylenediamine were reacted in an equimolar amount in N-methyl-2-pyrrolidone, a solid content concentration of 18%, A solution having a viscosity of about 50 Pa · s was prepared. This was put in an annular coating tank 7 having an inner diameter of 80 mm and a height of 50 mm. At the center of the annular coating tank, an annular sealing material 8 made of hard polyethylene having a thickness of 29 mm and having an inner diameter of 29 mm was attached.

  As the annular body 5, a hollow body made of polyacetal resin having a hole 6 with a height of 25 mm, an outer diameter of 60 mm, and an inner diameter of the narrowest part of 31.2 mm was prepared. The inner wall is an inclined surface, and the inclination angle formed with the vertical line is 7 °. The roundness of the hole 6 was 13 μm. Three arms made of stainless steel rods with a length of 30 mm and a thickness of 0.5 mm were attached to the outer surface of the annular body at equal intervals. The arm was placed on the upper edge of the annular coating tank 7 and placed on the coating solution.

  Next, the core body 1 was raised at a speed of 0.8 m / min while visually detecting the height of the annular body 5 from the liquid level, and the annular body 5 was immediately lifted by about 15 mm from the liquid level. Furthermore, the height of the annular body 5 increased. Therefore, the speed was gradually decreased, and when the core body 1 was raised by about 60 mm, the height of the annular body 5 was stabilized at 20 mm, so the ascent speed of the core body was made constant. The speed at that time was 0.6 m / min.

  During the rising of the core body 1, the annular body 5 did not contact the core body 1, and the coating film 4 having a wet film thickness of about 600 μm was formed. About 1 minute after coating, the core was taken out, leveled, and dried at 120 ° C. for 30 minutes while rotating at 10 rpm.

Next, the core body 1 was placed in a heating furnace in a vertical direction, and the core body was heated while a thermocouple wire was attached to the inner surface of the core body and the temperature was measured. As shown in FIG. 12D, the temperature was raised to 250 ° C. in 30 minutes, held at 250 ° C. for 30 minutes, then raised to 380 ° C. in 20 minutes, held at 380 ° C. for 40 minutes, and then 1 hour It returned to normal temperature over 30 minutes.
Under this condition, it is placed at 250 ° C. for 2 hours and 10 minutes and at a temperature of 300 ° C. or more for 1 hour and 15 minutes. Note that 380 ° C. is a temperature at which PFA described later can be fired.

  After the core 1 was cooled to room temperature, the film was taken out to obtain an endless belt made of PI resin. The film thickness was 80 μm and was almost uniform. The endless belt was cut open, and test specimens were cut out from 10 locations, and the number of flexing until rupture was measured with an MIT tester (FT701 model manufactured by Ueshima Seisakusho). The maximum value was 3900 times, the minimum value was 3150 times, and the average value A result of 3540 times was obtained.

  Separately, the core body 1 coated with the PI precursor solution and dried was coated with an adhesive tape at one end of the film. In addition, an aqueous paint of PFA (trade name: 710CL, manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd., concentration 60%, viscosity 400 mPa · s, containing ethanol and t-butanol as a solvent in addition to water), inner diameter 90 mm, height In a 480 mm coating tank, the core 1 was immersed in a vertical state with the coating on the bottom, leaving only 5 mm of the upper PI precursor film. Subsequently, it pulled up at a speed of 0.3 m / min to form a PFA coating film.

  After drying at 80 ° C. for 10 minutes, the coating was removed. Thereafter, the PI precursor was reacted by heating under the above conditions to form a PI resin film, and the PFA coating film was baked. After cooling to room temperature, the film was removed from the core 1 to obtain an endless belt. The adhesion between the PI resin and the PFA layer was strong. When the film thickness was measured, the PI resin was 80 μm and the PFA layer was 30 μm. This endless belt was cut into a length of 320 mm to obtain a fixing belt.

  This fixing belt was used in a fixing device described in JP-A No. 11-133776, and an image fixing test was conducted. In the fixing device, the fixing belt is repeatedly rotated while being deformed, but the fixing belt can be used without any trouble even when the durability test of 50,000 sheets of A4 paper is performed. However, due to the wear of the PFA layer, the life as a fixing belt was exhausted with about 100,000 sheets, but there was no problem with the PI resin layer.

<Reference Example 2>
In Reference Example 1, as shown in FIG. 12E, the heating condition of the PI resin was raised to 380 ° C. over 1 hour, then held at 380 ° C. for 40 minutes, and then returned to room temperature over 1 hour 20 minutes. It was. Under this condition, it is placed at 250 ° C. for 1 hour and 30 minutes and at a temperature of 300 ° C. or higher for 1 hour and 15 minutes, and the time at 250 ° C. is insufficient. In the same manner as in Example 1, when the number of flexing until the rupture occurred was measured with an MIT test machine, the maximum value was 1200 times, the minimum value was 750 times, and the average value was 940 times.

  When a fixing belt was formed by forming a PFA layer on the surface and evaluated in the same manner, the fixing belt cracked from the end of about 40,000 A4 sheets, and fractured. Since the fixing belt is repeatedly deformed, the inferior bending resistance results in a short life.

<Reference Example 3>
In the same manner as in Example 1, a coating film was formed on the cylindrical core. Next, the core was axially horizontal within 3 minutes and dried at 140 ° C. for 30 minutes while rotating at 6 rpm. In the dryer, hot air blows down from above at a speed of about 5 m / s and hits the core.

  Next, as shown in FIG. 13, the core body was placed vertically, and a cover 30 made of a stainless steel cylinder having a thickness of 0.5 mm and a diameter of 460 mm was attached to the outside of the core body 32 and placed in a heating furnace. Among them, hot air was flowing from the side surface at a speed of about 2 m / s. However, since the cover 30 was present, the hot air did not directly hit the core body 32. Next, as shown in condition (a) of FIG. 11, the temperature was raised from room temperature to 300 ° C. in 2 hours, held at 300 ° C. for 1 hour and 20 minutes, and cooled to room temperature in 1 hour and 40 minutes. In this case, it was placed at 250 ° C. for 2 hours and at 300 ° C. for 1 hour and 20 minutes. By removing the film after cooling to room temperature, an endless belt made of PI resin could be obtained.

  When the film thickness was measured, it was uniform at 80 μm except for 30 mm from the upper end. The film thickness within 30 mm from the upper end part had a thick part and a thin part in the circumferential direction, but this was a little until the annular body moved in the horizontal direction and the gap with the core body was evenly fitted. It is thought that it took time.

Next, in the same manner as in Reference Example 1, the belt was cut open and test pieces were cut out from 10 locations, and the number of flexing until rupture was measured with an MIT test machine. The maximum value was 1800 times and the minimum value was 1100. The average value was 1550 times.
In addition, FIG. 14 shows the result of measuring the volume resistance finely after cutting the endless belt. In the figure, the horizontal axis indicates the position of the endless belt in the circumferential direction, the vertical axis indicates the position of the endless belt in the axial direction, the scale is an arbitrary coordinate, and the numerical value in the figure indicates an index of volume resistance. According to this result, the volume resistance was in the range of 10 ^9.1 to 10 ^9.4 Ωcm, and the variation was small.
This endless belt can be used as an electrophotographic transfer belt. Even if the endurance test of 50,000 sheets of A4 paper is performed on a roll having a diameter of 20 mm, the transfer belt should be used without any problem. I was able to.

<Reference Example 4>
In Reference Example 3, as heating conditions for imidization, the temperature was raised from room temperature to 300 ° C. in 2 hours, held at 300 ° C. for 30 minutes, and cooled to room temperature in 1 hour and 40 minutes. In this case, it was placed at 250 ° C. for 1 hour and at 300 ° C. for 30 minutes. Otherwise, an endless belt was produced in the same manner, and the number of flexing until breakage was measured in the same manner as in Example 2. The maximum value was 1100 times, the minimum value was 700 times, and the average value was 850 times.
When this endless belt is stretched around a roll with a diameter of 20 mm and used as a transfer belt for electrophotography, when the endurance test of A4 paper is performed, the transfer belt breaks from the end of about 20,000 sheets, and durability The result was insufficient.

It is explanatory drawing which shows an example of the dispersion | distribution method of carbon black. It is a schematic block diagram which shows an example of a coating device. It is the schematic plan view (a) and schematic sectional drawing (b) which show the circular electrode which measures surface resistivity. It is the schematic plan view (a) and schematic sectional drawing (b) which show the circular electrode which measures volume resistivity. It is explanatory drawing which shows the determination method of the mixing ratio for setting it as a desired resistance value. It is explanatory drawing which shows an example of the method of producing a resistance confirmation member. It is explanatory drawing which shows an example of the method of producing a resistance confirmation member, (A) shows the state before coating-film formation, (B), (C) shows the state after coating-film formation. It is explanatory drawing which shows another example of the method of producing a resistance confirmation member. It is explanatory drawing which shows another example of the method of producing a resistance confirmation member, (A) shows the state before coating-film formation, (B), (C) shows the state after coating-film formation. It is a figure which shows the surface resistivity for every coating material. It is a graph which shows an example of the heating conditions of a coating film. It is a graph which shows another example of the heating conditions of a coating film. It is a schematic diagram which shows the cylindrical core body which provided the cover. It is a figure which shows distribution of the volume resistivity of an endless belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 32 ... Cylindrical core body, 2 ... Solution, 3 ... Axis, 4 ... Coating film, 5 ... Ring body, 6 ... Circular hole of an annular body, 7 ... Ring coating tank, 8 ... Sealing material, 10 ... Substrate, DESCRIPTION OF SYMBOLS 12, 22 ... Adhesive tape, 14 ... Scraping rod, 16, 26 ... Test paint, 20 ... Cylindrical base | substrate, 30 ... Cover, 50 ... 1st flow pipe, 52 ... Connection pipe, 54 ... 2nd flow pipe

Claims (5)

A step of preparing a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a viscosity adjusting liquid not containing carbon black, and applying the semiconductive paint to form a semiconductive member A process for producing a semiconductive member comprising the steps of:
Carbon black is dispersed in a resin solution having a viscosity in the range of 1 to 20 Pa · s to prepare the carbon black dispersion, and the carbon black dispersion is mixed with a viscosity adjusting liquid having a higher viscosity than the resin solution. A method for producing a semiconductive member, comprising producing a semiconductive paint.   The method for producing a semiconductive member according to claim 1, wherein the carbon black dispersion is performed by colliding a mixed liquid of carbon black divided into two or more at a pressure of 150 MPa or more. A process for preparing a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a resistance adjusting liquid not containing carbon black, and applying the semiconductive paint to form a semiconductive member A process for producing a semiconductive member comprising the steps of:
Two or more kinds of test paints having different mixing ratios of the carbon black dispersion liquid and the viscosity adjusting liquid are prepared in advance, each of the resistance check members is molded using the test paint, and the resistance value of each of the resistance check members A method for producing a semiconductive member, comprising: determining a mixing ratio of a carbon black dispersion liquid and a resistance adjusting liquid in the semiconductive paint. A process for preparing a semiconductive paint by mixing a carbon black dispersion liquid in which carbon black is dispersed in a resin solution and a resistance adjusting liquid not containing carbon black, and applying the semiconductive paint to form a semiconductive member A process for producing a semiconductive member comprising the steps of:
A prepared semi-conductive paint B and a semi-conductive paint A having a known resistance value as a semi-conductive member are mixed at a constant mixing ratio to prepare a mixed paint, and the resistance confirmation member is prepared using the mixed paint The method of manufacturing a semiconductive member is characterized in that the mixing ratio of the carbon black dispersion liquid and the resistance adjusting liquid in the semiconductive paint B is readjusted from the resistance value of the resistance confirmation member.   An endless belt using a semiconductive member obtained by the method for producing a semiconductive member according to any one of claims 1 to 4.

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