JP2006056972A - Conductive seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a conductive seamless belt causing no problem of image quality decline(color drift, image blur) through improving its creep quality required for improvement while using a polyamideimide and making the best use of its characteristics including excellent initial modulus and flame retardancy inherent therein. <P>SOLUTION: The conductive seamless belt is obtained by compounding the polyamideimide, polyethersulfone and a conductive filler. In this conductive seamless belt, the polyamideimide and the polyethersulfone are made into a polymer alloy. For this belt, it is preferable that the polyamideimide and the polyethersulfone be compounded in the weight ratio of (95:5) to (50:50) and the conductive filler be compounded at 1-50 pt(s). wt. based on a total of 100 pts. wt. of the polyamideimide and the polyethersulfone. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive seamless belt used for an image forming apparatus using an electrophotographic system such as an electrophotographic copying machine, a laser printer, a facsimile, and a composite apparatus thereof, and more particularly a conductive seamless belt that can be suitably used for a color image forming apparatus. About.

  An image forming apparatus using an electrophotographic system forms a uniform charge on a photoconductor composed of an inorganic or organic conductive material, and forms an electrostatic latent image on the photoconductor with writing light from an exposure unit. Thereafter, the electrostatic latent image is developed with toner from the developing unit to form a toner image on the photoreceptor. Next, the toner image formed on the photosensitive member is transferred to the intermediate transfer member. In the case of mono-color, this operation is performed once. In the case of full-color image formation, a multicolor image other than full-color is formed four times with yellow (Y), magenta (M), cyan (C), and black (K). In this case, the number of times corresponding to the two or three toner colors to be used is repeated, and the toner formed after primary transfer to the intermediate transfer member (so that the toner images are sequentially superimposed in the case of a multicolor image) The images are collectively transferred to a recording medium such as paper. Finally, the toner image transferred to the recording medium is fixed on the recording medium by the fixing unit and output. In addition to the cycle type apparatus as described above, the color image forming apparatus includes a tandem type in which a plurality of image carriers on which toner images of different colors are formed are arranged in series on an intermediate transfer body. There is a color image forming apparatus.

  As a seamless belt used as an intermediate transfer member or the like of such an image forming apparatus, it is necessary to play a role of accurately superimposing toner of 2 to 4 colors on the belt so that accurate rotation performance can be obtained. In order to achieve this, the dimensional stability of the belt is required.

  Recently, in the field of color printers and the like, high image quality similar to that of inkjet has been demanded, and a polyamideimide seamless belt has been proposed as a belt that satisfies the requirements of dimensional stability for high image quality. (For example, refer to Patent Document 1). This belt has a high initial elastic modulus, and even if the tensioned state continues, the decrease from the initial elastic modulus is small and the elongation is small, which leads to prevention of color misregistration and image blurring. . Also, the use of polyamideimide matches the industry trend for requiring flame resistance of OA equipment because polyamideimide itself has flame retardancy.

However, when a seamless belt made of polyamideimide is used in the image forming apparatus, the seamless belt is inferior in creep properties, so that the portion in contact with the roll is fixed in a roll shape when the image forming apparatus is stopped. As a result, there is a problem in that the belt is likely to have a roll-shaped wrinkle, and as a result, the image quality is deteriorated (color shift, image blur).
JP 2003-261768 A

  Therefore, the present invention uses a polyamide-imide to improve the creep properties that are required to be improved while taking advantage of its excellent initial elastic modulus and flame retardancy, thereby reducing the image quality (color shift, image blur). An object of the present invention is to provide a conductive seamless belt that does not cause the above problem.

  As a result of diligent research to achieve the above object, when blending polyethersulfone and a conductive filler in polyamideimide and making both polymers into a polymer alloy, the creep property is improved and the above-mentioned problem of image quality deterioration is solved. The present inventors have found that a conductive seamless belt can be obtained and completed the present invention.

  That is, the first invention of the present invention is a polyamide imide (hereinafter referred to as PAI), polyethersulfone (hereinafter referred to as PES), and a conductive filler, wherein the PAI and the PES are polymerized. A conductive seamless belt characterized by being alloyed.

  The PAI used in the present invention is not particularly limited as long as it is a so-called polyamideimide (a polymer having a repeating unit containing an amide group and an imide group), but it is a reaction between trimellitic anhydride and diisocyanate or diamine, or trimellitic anhydride. It is preferable to use a polyamideimide obtained by the reaction between chloride and diamine.

  In this case, the diisocyanate has a ring structure of phenyl group, diphenyl group, naphthalene group as a basic skeleton, and two isocyanates directly bonded to these basic skeletons, such as tolylene diisocyanate, 3,3′-dimethylbiphenyl. -4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, It is preferable to use naphthalene-1,5-diisocyanate or naphthalene-2,6-diisocyanate, and the diamine has a ring structure corresponding to these diisocyanates (a compound in which an amino group is substituted instead of an isocyanate group). To use preferable. That is, as PAI, N of an imide group and N of an amide group contained in the repeating unit are bonded by a ring structure of a phenyl group, a diphenyl group, or a naphthalene group (that is, via these ring structures). It is preferable to use those that are used.

  In addition, the conductive filler is not particularly limited as long as it is a filler that can be used to impart conductivity to the belt, but a metal or alloy such as carbon black, graphite, aluminum, copper, iron, nickel, a copper alloy, Alternatively, fine powders of metal oxides such as tin oxide, zinc oxide, titanium oxide, tin oxide-indium oxide or tin oxide-antimony oxide composite oxide are exemplified. These metals, alloys or metal oxides can be used alone or in admixture of two or more. Among them, it is preferable to use carbon black because it is inexpensive and versatile.

  The polymer alloy as used in the present invention is used in a broad sense, and it is a narrowly-defined polymer in a blend of different types of polymers (a state in which they are uniformly mixed without causing phase separation (completely compatible state and / or interfacial affinity phase separated state)). It includes not only alloys but also blends in an incompatible phase separation state), block copolymers and graft copolymers of different polymers, and an interpenetrating polymer network (IPN) in which different polymers are intertwined in a network.

  Examples of the use of the conductive seamless belt of the present invention used in an image forming apparatus using an electrophotographic method include use as a photoreceptor belt, use as an intermediate transfer belt, use as a conveyance transfer belt, and the like. .

  A second aspect of the present invention is the conductive seamless belt according to the first aspect, wherein the PAI and the PES are blended in a weight ratio of 95/5 to 50/50. It is.

  PAI and PES are used in a weight ratio of 95/5 to 50/50 when PAI exceeds 95/5 when such a seamless belt is used in an image forming apparatus. The obtained image has sufficiently improved the problem of image quality degradation such as color misregistration caused by aging of the belt when using a PAI single seamless belt without PES (hereinafter referred to as “PAI single seamless belt”). When the belt is less than 50/50, a high-quality image (equivalent to an image obtained by a PAI single seamless belt at the beginning of use) tends not to be obtained. Because. This is because when the PAI exceeds 95/5, the creep property of the seamless belt is not sufficiently improved by PES. On the other hand, when the PAI is less than 50/50, the elastic modulus of the seamless belt is greatly reduced compared to the PAI single seamless belt, This is considered to be due to insufficient dimensional stability of the belt.

  Of the present invention, the third invention is characterized in that the blending amount of the conductive filler is 1 to 50 parts by weight with respect to 100 parts by weight of the total amount of the PAI and the PES. A conductive seamless belt according to the second invention.

  The conductive filler is used in an amount of 1 to 50 parts by weight with respect to 100 parts by weight of the total amount of the PAI and the PES. The conductive filler exceeds 50 parts by weight. On the other hand, if the conductive filler is less than 1 part by weight, the electric resistance of the belt becomes high and sufficient static electricity is not generated on the belt. This is because a high-quality image may not be formed because it causes a transfer failure.

  1. The seamless belt of the first invention has improved creep properties as compared with the PAI single seamless belt by converting PAI and PES into a polymer alloy. As a result, when the PAI single seamless belt is used for the image forming apparatus, this belt is inferior in creep property, and therefore, the part in contact with the roll is fixed in the roll shape when the apparatus is stopped. Then, there was a problem that the roll-shaped wrinkles were likely to occur on the belt, leading to a decrease in image quality (color shift, image blur), but this problem was improved or eliminated. Further, since PES also has flame retardancy, this belt sufficiently maintains the flame retardancy of the PAI single seamless belt without impairing the flame retardancy of PAI.

  2. In the seamless belt of the second invention, PAI and PES are used in a weight ratio of 95/5 to 50/50, so that the creep property of the seamless belt is sufficiently good and hardly wrinkled. Also, since the elastic modulus has a sufficient value, the deformation of the belt is small, and the image obtained when this belt is used in the image forming apparatus is equivalent to the image quality at the initial use when the PAI single seamless belt is used. In addition, in the case of a PAI single seamless belt, the problem of image quality deterioration such as the color shift caused by the change of the belt with time is improved or eliminated.

  3. Furthermore, the seamless belt of the third invention has found an appropriate blending amount of the conductive filler to the polymer alloyed PAI and PES, and the blending amount of the conductive filler is a total amount of PAI and PES of 100. When used at a ratio of 1 part by weight to 50 parts by weight with respect to parts by weight, the obtained image has higher quality than when used at a ratio outside this range.

  Hereinafter, the best mode for carrying out the present invention will be described, but the present invention is not limited to these modes. The seamless belt according to the present invention is manufactured as follows.

(Preparation of cast solution for centrifugal molding)
For example, the following PAI and PES are used in a weight ratio of 95/5 to 50/50, to which a polar solvent such as N-methyl-2-pyrrolidone (NMP), DMF or DMAc is added, and For the production of a belt by centrifugal molding, for example, carbon black is blended as a conductive filler in a proportion of 1 to 50 parts by weight with respect to 100 parts by weight of the total amount of PAI and PES, and thoroughly mixed with a ball mill or the like. Make a casting solution. In this case, the polymer concentration of the cast solution is preferably 1 to 30% by weight. In this case, various organic / inorganic additives such as other polymers, extenders, various pigments, ultraviolet absorbers, antistatic agents, dispersants, neutralizing agents, and the like can be added as additional components. Of course.

(PAI)
As described above, as PAI, N of an imide group and N of an amide group contained in the repeating unit are formed by a ring structure of a phenyl group, a diphenyl group, or a naphthalene group (that is, through these ring structures as a medium). It is preferable to use one that is bonded. Examples of commercially available products include Viromax HR-16NN (manufactured by Toyobo Co., Ltd.), Viromax HR-11NN (manufactured by Toyobo Co., Ltd.), Torlon 4203L (manufactured by Solvay Advanced Polymers), and the like.

(Seamless belt molding)
The conductive seamless belt according to the present invention can be obtained by injecting the cast solution into a drum of a centrifugal molding machine and performing centrifugal molding by a conventional method.

  The seamless belt of polymer components as described above is easy to centrifuge and is considered to be a polymer alloy in a narrow sense because PAI and PES are dissolved in a polar solvent and mixed uniformly. As a result of the greatly improved creep performance as compared with the belt, the problems such as color shift and image blur observed in the single seam level of PES were improved or eliminated. In addition, the flame retardancy of the PAI single seamless belt is sufficiently maintained.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples.

Example 1
PAI (trade name: Viromax HR-16NN, manufactured by Toyobo Co., Ltd.) and PES (trade name: SUMIKAEXCEL PES 4100P, manufactured by Sumitomo Chemical Co., Ltd.) are blended at a ratio of 70 parts by weight for the former and 30 parts by weight for the latter. After adding 16 parts by weight of acetylene black (trade name Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) to 100 parts by weight of this resin component, NMP was added as a solvent so that the resin component concentration was 15%. Then, this is sufficiently mixed with a ball mill or the like to prepare a cast solution for belt production by centrifugal molding. Subsequently, the cast solution was put into a centrifugal molding machine, heated at a rotor rotation speed of 300 rpm and a rotor internal temperature of 100 ° C. for 1 hour, and further heated at 200 ° C. for 6 hours, whereby a diameter of 150 mm, a length of 266 mm, and a thickness of A 100 μm conductive seamless belt (see FIG. 1 for the form, except for the dotted line portion) was obtained.

(Example 2)
PAI (trade name: Viromax HR-16NN, manufactured by Toyobo Co., Ltd.) and PES (trade name: Sumika Excel PES 4100P, manufactured by Sumitomo Chemical Co., Ltd.) are blended in a proportion of 50 parts by weight for the former and 50 parts by weight for the latter. After adding 16 parts by weight of acetylene black (trade name Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) to 100 parts by weight of this resin component, NMP was added as a solvent so that the resin component concentration was 15%. Then, this is sufficiently mixed with a ball mill or the like to prepare a cast solution for belt production by centrifugal molding. Subsequently, the cast solution was put into a centrifugal molding machine, heated at a rotor rotation speed of 300 rpm and a rotor internal temperature of 100 ° C. for 1 hour, and further heated at 200 ° C. for 6 hours, whereby a diameter of 150 mm, a length of 266 mm, and a thickness of A 100 μm conductive seamless belt was obtained (see FIG. 1 for the form, except for the dotted line portion).

(Comparative Example 1)
Only PAI (trade name: Viromax HR-16NN, manufactured by Toyobo Co., Ltd.) is used as the resin component, and 16 parts by weight of acetylene black (trade name, Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) is added to 100 parts by weight of the resin component. After adding NMP as a solvent so that the resin component concentration is 15%, the mixture is sufficiently mixed with a ball mill or the like to prepare a cast solution for belt production by centrifugal molding. Subsequently, the cast solution was put into a centrifugal molding machine, heated at a rotor rotation speed of 300 rpm and a rotor internal temperature of 100 ° C. for 1 hour, and further heated at 200 ° C. for 6 hours, whereby a diameter of 150 mm, a length of 266 mm, and a thickness of A 100 μm conductive seamless belt was obtained.

(Comparative Example 2)
Only PES (trade name Sumika Excel PES 4100P, manufactured by Sumitomo Chemical Co., Ltd.) is used as the resin component, and 16 parts by weight of acetylene black (trade name Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) is added to 100 parts by weight of the resin component. After adding NMP as a solvent so that the resin component concentration is 15%, the mixture is sufficiently mixed with a ball mill or the like to prepare a cast solution for belt production by centrifugal molding. Subsequently, the cast solution was put into a centrifugal molding machine, heated at a rotor rotation speed of 300 rpm and a rotor internal temperature of 100 ° C. for 1 hour, and further heated at 200 ° C. for 6 hours, whereby a diameter of 150 mm, a length of 266 mm, and a thickness of A 100 μm conductive seamless belt was obtained.

(Elastic modulus evaluation test)
The elastic modulus of the seamless belts of Examples 1 and 2 and Comparative Examples 1 and 2 was measured according to JIS K 7127. That is, measurement was performed at a test speed of 50 mm / min using a 10 mm × 150 mm strip test piece.

(Creep property evaluation test)
For the conductive seamless belts of Examples 1 and 2 and Comparative Examples 1 and 2, the creep rate was measured and the creep property was evaluated as follows.
1. Measurement conditions (1) A test piece (width 50 mm × length 80 mm) is cut from the belt so that the circumferential direction of the belt is the longitudinal direction (see the dotted line portion in FIG. 1) (state before being left in the tube in FIG. 2) reference).
(2) The test piece is placed in an aluminum tube (φ18 mm) so that the length direction is rounded.
(3) The aluminum tube containing the test piece is allowed to stand for 120 hours under the conditions of 40 ° C. and relative humidity of 95% (see the in-tube standing state in FIG. 2).
(4) The test piece is taken out from the aluminum tube under conditions of 23 ° C. and relative humidity 65% (see the state after being left in the tube in FIG. 2), and the creep rate after 1 minute is measured.
2. Calculation of creep rate Creep rate = (abx) / a × 100
a: Distance between end portions in the length direction before leaving the test piece in the tube (unit: mm).
x: distance between the end portions in the length direction when the test piece is left in the tube (distance of the overlapped portion, unit is mm).
b: Distance between end portions in the length direction after the test piece was left in the tube (unit: mm).

(Image quality (color shift) evaluation test)
In the color printer (LP-3000C, manufactured by Epson Corporation), the seamless belts of Examples 1 and 2 and Comparative Examples 1 and 2 were attached as intermediate transfer belts, respectively, after 1 day, after 30 days, after 90 days, Each was subjected to an image formation test. The copy image obtained at the beginning of each of these tests was observed with a magnifying lens, and color misregistration (that is, toner positional deviation) and image quality were visually evaluated according to the following criteria.
◎ There is no toner misalignment and the image quality is very good.
○ There is almost no toner misalignment and the image quality is relatively good.
Δ Some toner misalignment is observed, and the image quality is slightly inferior.
X Toner misalignment is noticeable and image quality is poor.

  For the conductive seamless belts of Examples 1 and 2 and Comparative Examples 1 and 2, the results of evaluation tests of the elastic modulus, creep property and image quality of these belts were summarized as shown in Table 1. Shown in

実施例１，２のシームレスベルトは、表１に示すように比較例１のＰＡＩ単独のシームレスベルトに比べ、クリープ率（癖のつきやすさの指標であり、この値が小さい程ベルトに癖がつきにくい。）がかなり小さくなっている。その結果、実施例１，２のシームレスベルトは、画像形成装置の停止状態においてロールに接触している部分がロール形状のままに固定されることになっても、比較例１のベルトに比べ、当該ベルトにロール形状の癖がつきにくく、そのため９０日を経ても、表１に示すように色ずれ等の画質低下を生じることなく、使用初期のＰＡＩ単独のシームレスベルトと同等の高画質を生み出すと考えられる。この場合、弾性率に着目しても、実施例１，２の弾性率は、比較例１より低下するものの、ＰＥＳ単独シームレスベルトの比較例２より十分大きく、画質を低下させない値となっている。

As shown in Table 1, the seamless belts of Examples 1 and 2 have a creep ratio (an index of ease of wrinkling, as compared with the seamless belt of PAI alone of Comparative Example 1, and the smaller this value, the more wrinkles the belt. It is hard to stick.) Is considerably small. As a result, the seamless belts of Examples 1 and 2 are compared with the belt of Comparative Example 1 even when the portion in contact with the roll is fixed in a roll shape when the image forming apparatus is stopped. The belt is not easily wrinkled in the roll shape, and therefore, even after 90 days, as shown in Table 1, it produces the same image quality as the PAI single seamless belt in the initial stage of use without causing image quality degradation such as color misregistration. it is conceivable that. In this case, even if paying attention to the elastic modulus, the elastic modulus of Examples 1 and 2 is lower than that of Comparative Example 1, but is sufficiently larger than Comparative Example 2 of the PES single seamless belt, and does not deteriorate the image quality. .

  On the other hand, Comparative Example 1 has a large creep rate and the belt is easily wrinkled. Therefore, after 30 days, the high image quality (equivalent image quality equivalent to the seamless PAI single seamless belt in the initial stage of use) cannot be maintained. The image quality is somewhat degraded. Further, in Comparative Example 2, since the value of the elastic modulus is not sufficient, the belt is easily deformed, and similarly, the high-quality image cannot be obtained.

  In addition, the seamless belts of Examples 1 and 2 can be said not to impair the flame retardancy of the PAI single seamless belt of Comparative Example 1, and thus can be said to be belts that make full use of the flame retardancy characteristics of PAI. .

(A) is a front view of the conductive seamless belt according to the present invention, (B) is a side view, (C) is a perspective view, and a portion surrounded by a dotted line in (C) is a creep rate measurement. It is an illustration of the part cut out as a test piece for. These are figures which show an example of each state after leaving in the aluminum pipe of the test piece for creep rate measurement of the conductive seamless belt which concerns on this invention, leaving in an aluminum pipe, and leaving in an aluminum pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive seamless belt 2 Example of the part cut out as a test piece for creep rate measurement 3 Test piece for creep rate measurement

Claims (3)

A conductive seamless belt comprising a polyamide imide, a polyether sulfone, and a conductive filler, wherein the polyamide imide and the polyether sulfone are polymer-alloyed. 2. The conductive belt according to claim 1, wherein the polyamideimide and the polyethersulfone are blended in a weight ratio of 95/5 to 50/50. The conductive amount according to claim 1 or 2, wherein the amount of the conductive filler is 1 to 50 parts by weight with respect to 100 parts by weight of the total amount of the polyamideimide and the polyethersulfone. Seamless belt.

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