JP2001109276A - Semiconductive belt for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive belt for an electrophotographic device which is less in elongation, is highly accurate and durability and is inexpensive. SOLUTION: This semiconductor belt has at least a three-layered structure including, successively from the side in contact a sheet body 12, the outermost layer 52, an elastic layer 53 and an arbor layer 54 and the moduli of elasticity of the respective layers are greater in order of the elastic layer 53, the outermost layer 52 and the arbor layer 54. The moduli of elasticity of the respective layers are preferably in a range of 1.0 to 60 Mpa for the elastic layer, 70 to 200 Mpa for the outermost layer and 250 to 2800 Mpa for the arbor layer. A composition having a release property is preferably incorporated into at least the outer peripheral part of the outermost layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive belt for an electrophotographic apparatus, and more particularly to an intermediate transfer belt and a transfer conveyance belt.

[0002]

2. Description of the Related Art Conventionally, an intermediate transfer belt for an electrophotographic apparatus,
As the transfer conveyance belt, a belt made of a synthetic resin such as a polyimide resin, a polyvinylidene fluoride resin, and a polycarbonate resin is used. Since the synthetic resin film is hard, the belt used for low elongation has an advantage that it does not crack. However, these synthetic resins are not only expensive but also difficult to extrude into a seamless structure, and have many problems in the process and high production cost. Further, with the recent improvement in image quality of electrophotographic apparatuses, it is required that the surface of the belt be an elastic body. The synthetic resin film belt has a hard surface, and is inferior in the ability to follow irregularities of the paper when transferring toner to paper or the like, and is inferior in reproducibility of fine images. In addition, if the surface is hard, the toner lacks the holding property to the surface, so that in the case of a color image in which four colors are superimposed, a color shift may occur, and there is a problem that quality requirements cannot be met.

It has been proposed that the belt itself be made of an elastomer having elasticity in order to make the surface elastic. However, since the elastomer has a large stiffness even at a low elongation, there is a problem that image unevenness due to the stiffness cannot be solved. . It has also been proposed to use a cord or canvas as the core layer, but the cord or canvas is made of a twisted yarn, and there is a problem that the belt meanders in a further direction.

In the prior art having a structure in which an elastic layer is further formed on the surface after forming a synthetic resin film, there is a problem that the cost is greatly increased since the forming process is doubled.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductive belt for an electrophotographic apparatus which solves the above-mentioned problems and has a small rivet, high precision, excellent durability and low cost. is there.

[0006]

According to the present invention, there is provided a semiconductive belt for an electrophotographic apparatus, comprising at least a three-layer structure including an outermost layer, an elastic layer and a core layer in order from the side in contact with the sheet member. A semiconductive belt for an electrophotographic apparatus, wherein the elastic modulus increases in the order of an elastic layer, an outermost layer, and a core layer.

According to the present invention, by providing an elastic layer having a low elastic modulus between the outermost layer and the core layer, the holding properties of the toner and the reproducibility of the image are remarkably improved as compared with the conventional hard surface of the resin belt. improves. It is necessary to impart semiconductivity to the belt having these structures, but any known method may be used for imparting semiconductivity.

Further, according to the present invention, the elastic layer has an elastic modulus of 1.0 to 1.0.
The elastic modulus of the outermost layer is 70 to 200 Mpa, and the elastic modulus of the core layer is 250 to 2800 Mpa.

According to the present invention, it is preferable that the elastic modulus of the elastic layer, the outermost layer and the core layer be in the above-mentioned range. When the elastic modulus of the elastic layer is less than 1.0 MPa, the elastic modulus is too low, and conversely, the image is disturbed. If it exceeds 60 Mpa, the toner holding effect is lost. However, even at 60 MPa, the belt cannot be cleaned because the elastic modulus is considerably lower than that of a conventional synthetic resin belt. Usually, the cleaning of the belt is performed by a cleaning blade. However, since the elastic modulus is low, the blade bites and the friction coefficient increases.

Therefore, an outermost layer having a higher elastic modulus than the elastic layer is provided outside the elastic layer. In this case, the thickness of the outermost layer is preferably 3 to 70 μm. The elastic modulus of the outermost layer is 70Mp
If it is less than a, the cleaning property is inferior and 200 MPa
When the ratio exceeds the above, the effect of the elastic layer is impaired.

With only the elastic layer having the above-mentioned elastic modulus and the outermost layer, the belt is stretched and the image is disturbed. In order to solve this problem, a layer having a higher elastic modulus than these two layers is provided as a core layer. As a result, it is possible to suppress stiffness. When the elastic modulus of the core layer is less than 250 MPa,
Nobi occurs. On the other hand, if it exceeds 2800 MPa, the core layer becomes too hard, so that it is not possible to cope with a layout having a small diameter shaft and a small winding angle, or a curl is formed.

Further, the present invention is characterized in that the elastic layer and the core layer are made of polyurethane or polyurea.

According to the present invention, the elastic layer and the core layer are preferably made of a polyurethane or polyurea resin which contains a small amount of chemicals and does not contaminate the mating material.

Further, the present invention is characterized in that at least the outer periphery of the outermost layer contains a composition having releasability.

According to the present invention, at least the outer peripheral portion of the outermost layer contains a composition that imparts releasability so that the toner is easily released. Thereby, the cleaning effect is further improved.

Further, the present invention is characterized in that the composition having release properties is one or more selected from the group consisting of fluororesins and silicones.

According to the present invention, a compound comprising fluorine and / or silicone is particularly preferred as a component imparting releasability. The compounds are also suitable for the requirement that the belt does not stretch.

The present invention is also characterized in that the toner image on the photosensitive member is transferred, and the intermediate transfer belt is further transferred to a sheet member.

Further, the present invention is characterized in that the transfer image is a transfer-conveying belt for transferring a toner image on a photoreceptor onto a sheet member and conveying the sheet member.

According to the present invention, the electroconductive semiconductive belt for electrophotography is suitably used for an intermediate transfer belt and a transfer conveyance belt. The intermediate transfer belt and the transfer conveyance belt are required to have a small stiffness and high precision, and the semiconductive belt of the present invention satisfies the requirements.

[0021]

FIG. 1 is a cross-sectional view of the periphery of a photoreceptor 1 of a color copying electrophotographic apparatus using a semiconductive belt for an electrophotographic apparatus as an intermediate transfer belt 6 according to the present invention.
The photoconductor 1 is uniformly charged by the charging roller 2.
The charged photoreceptor 1 is exposed by light reflected from a copy object (not shown). In the case of a color copy, the reflected light is separated into blue, green, and red by a color filter, and is separately exposed. For example, light transmitted through a blue color filter forms an electrostatic latent image on the photoreceptor 1 by yellow light, which is a complementary color of blue. The photoreceptor 1 rotates in the direction indicated by the arrow 3, comes into contact with the first developing roller 4Y, is supplied with yellow toner from the first developing roller 4Y, and the yellow component of the copy object is developed. Second to fourth developing rollers 4M, 4C, 4
B is not in contact with the photoconductor 1, and the photoconductor 1 is in contact with the transfer belt 6 by the first transfer roller 5. The transfer belt 6 is moved in the direction of arrow 9 by the two pulleys 7 and 8, and the yellow image on the photoconductor 1 is transferred onto the transfer belt 6. The photoreceptor 1 is removed from the remaining yellow toner by a cleaning blade, and is discharged.

When the exposure through the yellow color filter is completed, the color filter is changed to green, and an electrostatic latent image is formed on the photoconductor 1 by magenta light, which is a complementary color of green. At this time, the first, third, and fourth developing rollers 4
Y, 4C, and 4B do not contact the photoconductor 1, only the second developing roller 4M contacts the photoconductor 1, and a magenta image is developed on the photoconductor 1. When the transfer of the yellow image is completed, the transfer belt 6 separates the first transfer roller 5 from the photoreceptor 1 and is rotated by the pulleys 7 and 8 in the direction opposite to the arrow 9 direction, and returns to the original position. When the magenta image on the photoconductor 1 comes to a position where it contacts the transfer belt 6, the magenta image on the photoconductor 1 is transferred to the transfer belt 6 by the first transfer roller 5.
As a result, the yellow image and the magenta image are superimposed on the transfer belt 6.

Similarly, a cyan image passed through a red color filter is developed on the photoreceptor 1 and superposed on the transfer belt 6. Finally, a black image is developed on the photoreceptor 1 and superimposed on the transfer belt 6 by white reflected light without using a color filter. As a result, the same color image as the object to be copied is formed on the transfer belt 6. The color image on the transfer belt 6 is transferred onto a sheet, for example, paper 12 supplied between the second transfer roller 11 and the pulley 8. The color image on the paper 12 is fixed on the paper 12 by a fixing device (not shown). After the transfer belt 6 transfers the color image to the recording paper, the remaining toner is removed by the cleaning blade 13.

FIG. 2 is a cross-sectional view of the periphery of the photoreceptor 1 of the electrophotographic apparatus for monochrome copying using the semiconductive belt for the electrophotographic apparatus of the present invention as the transfer / conveying belt 21. The photoconductor 1 is uniformly charged by the charging roller 2. The charged photoreceptor 1 is exposed by light reflected from a not-shown copy body to form an electrostatic latent image. The electrostatic latent image is
The toner is developed by the black toner supplied from the developing roller 4, is transferred onto the paper 12 at the point of contact with the transfer / transport belt 21, and is further moved by the transfer / transport belt 21 to the point of contact between the heating roller 24 and the pressure roller 25. The toner image is conveyed and fixed. The heating roller 24 is provided with a heating means 26. The transfer conveyor belt 21 includes two pulleys 22,
23 moves in the direction of the arrow. The photosensitive member 1 is removed of toner by a cleaning blade 10 as in FIG.

The toner is stored in a toner box 31, stirred by a stirrer 32, and supplied to a developing roller 4 via a supply roller 33. Excess toner on the developing roller 4 is regulated by the regulating blade 34, and a constant toner is always supplied from the developing roller 4 onto the photoconductor 1. Such a toner supply unit 30 is provided also in each of the developing rollers 4Y, 4M, 4C, and 4B in FIG.
It is omitted because the drawing becomes complicated.

FIG. 3 is a sectional view of a fixing device 40 of an electrophotographic apparatus using the semiconductive belt for an electrophotographic apparatus of the present invention as a fixing belt 41. The developed paper 12 is heated and pressed between the fixing belt 41 and the pressure roller 42, and the developed image is fixed on the paper 12. Fixing belt 41
Moves in the direction of the arrow with two pulleys. Fixing belt 41
The pulley 43 on the contact side with the pressure roller 42 has a heating means 43 inside, and the fixing belt 41
Heated by

FIG. 4 is a cross-sectional view of a semiconductive belt 51 for an electrophotographic apparatus according to one embodiment of the present invention. Belt 51
Has a three-layer structure composed of an outermost layer 52, an elastic layer 53, and a core layer 54 in order from the side in contact with the sheet body, for example, the paper 12, and the elastic modulus of each layer is elastic layer 53, outermost layer 52, and core layer 5
The order of 4 is not large as described in the example below.

(Example 1) 99 parts of polyisoprene polyol (manufactured by Idemitsu Petrochemical Co., trade name of poly IP) and 1 part of conductive carbon were kneaded, mixed, dehydrated, and mixed with isophorosine isocyanate (Sumitomo). Made of Bayer urethane,
10.3 parts of Desmodur I), 0.05 parts of tin-based cibutyltin sialate as a catalyst and mixing for 2 to 3 minutes to obtain a thermosetting polyurethane having an elastic modulus of 1 MPa. The elastomer raw material was adjusted to obtain an elastic layer stock solution.

After kneading and mixing 99 parts of polyurethane (trade name, Takenate L2690, manufactured by Takeda Pharmaceutical Co., Ltd.) and 1 part of conductive carbon, the mixture was defoamed under reduced pressure, and a curing agent (trade name, MOCA trade name, manufactured by Ihara Chemical) 12.3 Parts, elastic modulus 25
The core layer stock solution was 0 Mpa.

Polyurethane (ME321 manufactured by Dainippon Seika Co., Ltd.)
100 parts of 8LP (trade name) and 10 parts of conductive carbon and 0.5 part of a fluororesin (trade name of MCF323 manufactured by Dainippon Ink and Chemicals, Inc.) were added and mixed to obtain an outermost layer stock solution having an elastic modulus of 70 Mpa.

In a centrifugal molding machine in which a mold heated to 140 ° C. rotates at 700 rpm, the elastic layer raw material is reduced to a thickness of 0.1 mm.
5 mm, the rotation speed was increased to 1000 rpm, an elastic layer was formed in a mold, and a core layer material was injected onto the elastic layer so as to have a thickness of 0.1 mm. rear,
The rotation was stopped, the mold was removed, and after-curing was performed at 110 ° C. for 12 hours. Further, the outermost layer stock solution was coated on the elastic layer by spraying and dried to obtain a semiconductive belt having a three-layer structure.

(Example 2) 11.6 parts of isocyanate (manufactured by BASF, trade name of Lupranate MI) was added to the above-mentioned polyisoprene polyol (poly IP) containing conductive carbon, and an elastic layer stock solution having an elastic modulus of 5 MPa was added. Obtained. Polyurea resin (Takeda L2790, manufactured by Takeda Pharmaceutical Co., Ltd.)
25 parts of curing agent (MOCA)
A core layer stock solution having an elastic modulus of 700 Mpa was obtained. Except that Dainichi Seika's Rezamine ME823LP (trade name) was used as the polyurethane, the elastic modulus was 1 in the same manner as in Example 1.
An outermost layer stock solution of 00 Mpa was obtained. A three-layered semiconductive belt was obtained in the same manner as in Example 1.

Example 3 An isocyanate (Sumitomo Bayer Urethane Industries, Sumidur N350) was added to the conductive carbon-containing polyisoprene polyol (poly IP).
(Trade name) was added to obtain an elastic layer stock solution having an elastic modulus of 60 Mpa. A core layer stock solution having an elastic modulus of 2800 Mpa was obtained in the same manner as in Example 1 except that a polyurea resin (manufactured by High Chemical Industries, trade name: Porea R603) was used. An outermost layer stock solution having an elastic modulus of 200 Mpa was obtained using a surface coating agent composed of a fluororesin composition (trade name: TR-310, manufactured by Dainippon Ink and Chemicals, Incorporated). A three-layered semiconductive belt was obtained in the same manner as in Example 1.

Comparative Example 1 100 parts of the above-mentioned conductive carbon-containing polyisoprene polyol (poly IP)
The procedure of Example 1 was repeated except that 8.3 parts of isophorosine isocyanate (Desmodur I) was added to obtain an elastic layer having an elastic modulus of 0.7 Mpa.

Comparative Example 2 The procedure of Example 1 was repeated except that RX801 (trade name) manufactured by Ihara Chemical Industry Co., Ltd. was used as the polyurea resin to obtain a core layer stock solution having an elastic modulus of 3000 Mpa.

(Comparative Example 3) Takeda L2705 (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) was used as a polyurethane, and 8.3 parts of a curing agent (MOCA) was used.
The procedure was the same as in Example 1 except that the stock solution for the core layer was obtained.

(Comparative Example 4) An outermost layer stock solution having an elastic modulus of 50 MPa was obtained in the same manner as in Example 1 except that Rezamine ME3148 (trade name) manufactured by Dainichi Seika was used as the middle elastic polyurethane.

Comparative Example 5 An outermost layer stock solution having an elastic modulus of 500 MPa was obtained in the same manner as in Example 1 except that ME3103 (trade name) manufactured by Dainichi Seika was used as the polyurethane.

(Comparative Example 6) Sumidur N3500 (trade name) manufactured by Sumitomo Bayer Urethane as an isocyanate
Was added to obtain an elastic layer stock solution having an elastic modulus of 80 Mpa. The core layer stock solution has the same elastic modulus of 700 Mp as in Example 2.
The urethane of a was used. The outermost layer stock solution used had the same elastic modulus of 70 Mpa as in Example 1.

(Comparative Example 7) The same procedure as in Example 1 was carried out except that the one containing no fluororesin composition was used as the outermost layer stock solution.

Tables 1 and 2 show the properties of the semiconductive belts obtained in the examples and comparative examples.

[0042]

[Table 1]

[0043]

[Table 2]

From the results shown in Table 1, the semiconductive belt of the present invention was suitable for use as a belt for an electrophotographic apparatus, particularly as an intermediate transfer belt without color shift. On the other hand, the semiconductive belt shown in the comparative example is not preferable because of the problems shown in the belt performance column.

[0045]

As described above, according to the present invention, the semiconductive belt for an electrophotographic apparatus has at least a three-layer structure including an outermost layer, an elastic layer and a core layer in order from the side in contact with the sheet member. Since the elastic modulus of each layer increases in the order of the elastic layer, the outermost layer, and the core layer, the holding properties of the toner and the reproducibility of the image are remarkably improved, and there is no need to use expensive raw materials.

Further, the semiconductive belt for an electrophotographic apparatus of the present invention can be suitably used as an intermediate transfer belt and a transfer conveyance belt.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the periphery of a photoconductor 1 of an electrophotographic apparatus using a semiconductive belt for an electrophotographic apparatus of the present invention as an intermediate transfer belt 6.

FIG. 2 is a cross-sectional view of the periphery of a photoreceptor 1 of an electrophotographic apparatus using a semiconductive belt for an electrophotographic apparatus of the present invention as a transfer / conveying belt 21.

FIG. 3 is a cross-sectional view of a fixing device 40 of an electrophotographic apparatus using a semiconductive belt for an electrophotographic apparatus of the present invention as a fixing belt 41.

FIG. 4 is a cross-sectional view of a semiconductive belt 51 for an electrophotographic apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 4, 4Y, 4M, 4C, 4B Developing roller 5, 11 Transfer roller 6 Intermediate transfer belt 10, 13 Cleaning blade 12 Paper (sheet body) 21 Transfer conveyor belt 24 Heating roller 25, 42 Pressure roller 26, 45 Heating means 40 Fixing device 41 Fixing belt 51 Semiconductive belt for electrophotographic device 52 Outermost layer 53 Elastic layer 54 Core layer

Continued on the front page F-term (reference) 2H032 AA05 BA09 BA18 BA23 4F100 AA37H AK17D AK36B AK36C AK51B AK51C AK52D AL05D AL09 AT00A AT00C BA03 BA04 BA07 BA10A BA10C BA10D BA26 CA21 EH31 EH2J00J06J06J00J06J07JJK01 CP032 DA036 FD116 GF00 GM01 GQ00 GQ02

Claims (7)

[Claims] 1. A semiconductive belt for an electrophotographic apparatus, which comprises at least a three-layer structure including an outermost layer, an elastic layer, and a core layer in order from the side in contact with the sheet member, wherein the elastic modulus of each layer is an elastic layer and an outermost layer. A semiconductive belt for an electrophotographic apparatus, wherein the size of the belt increases in the order of the core layer. 2. The elastic layer has an elastic modulus of 1.0 to 60 Mpa,
2. The semiconductive belt according to claim 1, wherein the outermost layer has an elastic modulus of 70 to 200 Mpa, and the core layer has an elastic modulus of 250 to 2800 Mpa. 3. The elastic layer and the core layer are made of polyurethane or
2. The semiconductive belt for an electrophotographic apparatus according to claim 1, wherein the semiconductive belt is made of polyurea. 4. The semiconductive belt for an electrophotographic apparatus according to claim 1, wherein at least the outer periphery of the outermost layer contains a composition having a releasing property. 5. The semiconductive belt for an electrophotographic apparatus according to claim 1, wherein the composition having release properties is one or more selected from the group consisting of a fluororesin and silicone. 6. The semiconductive belt for an electrophotographic apparatus according to claim 1, wherein the intermediate transfer belt transfers a toner image on a photoreceptor to a sheet member. 7. A semiconductive belt for an electrophotographic apparatus according to claim 1, wherein the transfer belt is a transfer conveyance belt for transferring a toner image on a photoreceptor onto a sheet member and conveying the sheet member.