JPH10193469A - Semiconductive plastic endless belt and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductive plastic endless belt not provided with a bending habit even if not used over a long period of time in a state stretched across rollers and capable of realizing the enhancement of the quality of a copy image. SOLUTION: Two layers extracted in the order of larger thickness among many layers of a multi-layered endless belt are set so as to satisfy a condition (A) that a conductive filler is contained in at least the inside layer among two layers and a condition (B) that the compounding ratio of a conductive filler with respect to the whole of the forming material of the inside layer among two layers is larger than that of the conductive filler with respect to the whole of the forming material of the outside layer by 3-27wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive plastic endless belt used as a transfer intermediate for copying toner on a photoreceptor in an electrophotographic copying machine, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, with the practical use of electrophotographic copying machines such as full-color copying machines, when a toner image developed on a photoreceptor is transferred to copying paper, the toner is temporarily transferred to a transfer intermediate. Thereafter, a process of transferring the image to a copy sheet is adopted.

One example is shown in FIG. That is, in this process, after the surface of the photosensitive drum 1 is charged by the charging roll 2, the slit exposure 4 of the light image of the original reaches the surface of the photosensitive drum 1 via the exposure mechanism 3, and the static light corresponding to the original image is formed. An electrostatic latent image is formed on the surface of the photosensitive drum 1 and the developing device 5
As a result, a toner image is formed. An endless belt 6, which is a transfer intermediate, is stretched over a primary transfer roller 7 and pressed against the photosensitive drum 1 under the photosensitive drum 1, and the developed toner image is formed on the photosensitive drum 1. Are transferred on the surface of the endless belt 6 in the order of each color by the repetitive running of the endless belt 6 in both the forward and reverse directions. When the endless belt 6 travels in the forward direction (the same direction as the photosensitive drum 1), the toner image is transferred to the copy paper 9 sandwiched between the endless belt 6 and the secondary transfer roller 8. . Note that the toner remaining on the surface of the endless belt 6 after the secondary transfer is collected by the cleaning blade 10, and the endless belt 6 is prepared for the next transfer. Further, the toner remaining on the surface of the photosensitive drum 1 after the primary transfer is
After that, the surface of the photosensitive drum 1 is discharged by the eraser lamp 12.

[0004]

The endless belt 6 has the following features.
Since it is stretched over several rollers such as the primary transfer roller 7 and the secondary transfer roller 8, the portion in contact with each of the rollers 7 and 8 is bent in an arc shape (see FIG. 5). If the electrophotographic copying machine incorporating the endless belt 6 is not used for a long time in this state, the bent form is given to the endless belt 6, and the endless belt 6 becomes bent. Further, if the endless belt 6 having the bending habit is used as it is, a defect such as white spots occurs in a copied image. Therefore, recently, in order to prevent the bending habit from being imparted to the endless belt 6, when the power of the electrophotographic copying machine is turned off, a mechanism for loosening the stretching force of the endless belt 6 is provided in the electrophotographic copying machine. Improvements have been made such as providing them.

[0005] However, in an electrophotographic copying machine whose size is being reduced in size and thickness, the provision of the above-described mechanism requires extra space, which is a major obstacle to size reduction and thickness reduction. Further, there is also a demand for higher quality of copied images of the electrophotographic copying machine, and it is necessary to eliminate a system which causes the above-mentioned problems such as white spots.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and even if it is not used for a long time in a state of being hung over a roller, it does not have a bending habit and can improve the quality of a copied image. It is an object of the present invention to provide a semiconductive plastic endless belt that can be realized and a method for producing the same.

[0007]

In order to achieve the above object, the present invention relates to an endless belt composed of multiple layers, wherein two layers extracted in order of thickness from among the above multilayers have the following requirements (A). ) And (B) are set as the first gist. (A) Of the two layers, at least the inner layer contains a conductive filler. (B) Among the two layers, the blending ratio of the conductive filler to the whole forming material of the inner layer is 3 to 27% by weight larger than the blending ratio of the conductive filler to the whole forming material of the outer layer.

A method for producing a multilayer endless belt provided with at least one layer containing a conductive filler, wherein a shaft body is prepared and a solvent solution of a material for forming each layer in the multilayer is prepared for each layer. Then, in a state where the shaft is vertical, the solvent solution for the material forming the innermost layer of the multilayer is repeatedly immersed and pulled up to repeatedly form the innermost layer forming material on the outer periphery of the shaft. Form a liquid film consisting of a solvent solution, then through a drying step to evaporate the solvent from the liquid film to form an innermost layer, this shaft with innermost layer, the material forming the other layers other than the innermost layer The solvent solution is sequentially immersed and pulled up to form a liquid film of each layer, and then, through a drying process, a multilayer including the innermost layer is formed on the outer periphery of the shaft, and then the shaft is removed. That the second point To.

That is, the present inventors have conducted a series of studies on a multi-layer endless belt used in an electrophotographic copying machine such as a full-color copying machine. In the process, when the multilayer endless belt is incorporated in an electrophotographic copying machine and used, the multilayer endless belt has an arc-shaped bending habit toward the inside of the belt because of the shrinkage force of each layer of the multilayer endless belt. Was found to be due to no difference between the two. That is, when the above-mentioned multilayer endless belt is used by being incorporated in an electrophotographic copying machine, it is stretched over several rollers, so as shown in FIG. 5, the outer layer 30 is pulled while the inner layer 30 is pulled. Layer 31 is compressed. If this state is maintained for a long period of time, the contraction force of the inner layer 31 and the contraction force of the outer layer 30 are substantially the same, so that the inward bending state of the multilayer endless belt does not return to the original state, It becomes a bending habit and is applied to the multilayer endless belt. Therefore, by setting the compounding ratio of the conductive filler in the inner layer to be greater than the compounding ratio of the conductive filler in the outer layer by a specific range, and by reducing the shrinkage force of the inner layer, the expected value is obtained. It has been found that the object can be achieved, and the present invention has been achieved.

[0010]

Next, an embodiment of the present invention will be described.

As shown in FIG. 1, for example, the semiconductive plastic endless belt of the present invention comprises an inner layer 13, an intermediate layer 14 adjacent thereto, and an outer layer 1 adjacent to the intermediate layer 14.
5 three-layer structure. The thickness of each of the above layers is the largest for the outer layer 15, then for the inner layer 13,
The intermediate layer 14 is set to be the smallest. Such a semiconductive plastic endless belt composed of multiple layers, when two layers are extracted in order of thickness from among the above multilayers, the outer layer 15
And the inner layer 13 are extracted.

The material for forming the inner layer 13 and the outer layer 15 is a fluororesin, a vinyl chloride resin, an ABS resin,
Polymethyl methacrylate (PMMA) or the like is used,
Among them, vinyl chloride resins are preferred. These can be used in combination of two or more. The materials for forming the inner layer 13 and the outer layer 15 may be the same or different.

The above-mentioned fluororesin is not particularly limited, but vinylidene fluoride-ethylene tetrafluoride copolymer (hereinafter abbreviated as "Poly (VdF-TFE)"), ethylene-tetrafluoroethylene copolymer Merging (ETF
E), polychlorotrifluoroethylene (PCTF
E), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA)
Are used. Among them, as a solvent-soluble,
Poly (VdF-TFE) is preferred. That is,
This is because the production method is advantageous.

As the solvent for the solvent-soluble fluororesin, methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, ethyl acetate, tetrahydrofuran and the like are used. Above all, Poly (VdF-TFE)
And acetone are preferred.

As a material for forming the intermediate layer 14 provided between the inner layer 13 and the outer layer 15, a polyamide resin or the like is used. Examples of the polyamide resin include N-methoxymethylated nylon (hereinafter abbreviated as “nylon 8”),
Nylon 12, copolymer nylon, and the like. In particular, nylon 8 is used to improve the adhesion strength between the inner layer 13 and the outer layer 15 and to prevent the two layers from mixing.
It is preferred to use

As the solvent for the polyamide resin, a single solvent such as methanol or ethanol, or a mixed solvent obtained by mixing water, toluene or the like with these single solvents,
Propanol, 2-propanol and the like are used. Among them, a combination of nylon 8 and a mixed solvent of methanol / water (methanol / water = 3/1) is preferable.

The inner layer 13, the intermediate layer 14, and the outer layer 1
5, at least one layer contains a conductive filler.
There must be. As the conductive filler, Al
Metal powder such as minium powder and stainless steel powder, c-Zn
O, c-TiO_Two, C-Fe _ThreeO_Four, C-SnO_TwoEtc.
Conductive metal oxide, graphite, carbon black, etc.
Conductive powder, quaternary ammonium salt, phosphate ester,
Sulfonate, aliphatic polyhydric alcohol, aliphatic alcohol
Ionic conductive agents such as rusulfate salts.
These conductive fillers may be used alone or in combination of two or more.
Used. Among these conductive fillers,
From the point of dispersibility, c-TiO_TwoAnd c-SnO_TwoIs preferred
New Note that the above “c−” means having conductivity.
Meaning.

In the two layers (in this case, the inner layer 13 and the outer layer 15) extracted in order of the thickness, the mixing ratio of the conductive filler contained in the material forming the inner layer 13 is determined by It must be set to be 3 to 27% by weight larger than the mixing ratio of the conductive filler to be used. That is, by maintaining this relationship, it is possible to prevent the resulting semiconductive plastic endless belt from bending inward. This is a major point of the present invention.

Therefore, when the outer layer 15 does not contain a conductive filler, the compounding ratio of the conductive filler to be contained in the inner layer 13 is in the range of 3 to 27% by weight based on the whole forming material of the inner layer 13. Must be set as follows. When the conductive filler is contained in the outer layer 15 in a predetermined ratio, the compounding ratio of the conductive filler to be contained in the inner layer 13 is 3% less than that of the outer layer 15.
It must be formulated to be up to 27% by weight. By satisfying such requirements, the shrinking force of the inner layer 13 can be made smaller than the shrinking force of the outer layer 15 and the inward bending of the semiconductive plastic endless belt can be prevented.

However, the compounding ratio of the conductive filler contained in the material for forming the inner layer 13 is preferably 50% by weight or less, and more preferably 30% by weight or less based on the entire material for forming the inner layer 13. It is. That is, if not within the above range, the mechanical properties of the inner layer 13 are significantly reduced,
Therefore, it is likely to be brittle and easily cracked. Needless to say, the blending ratio of the conductive filler in the outer layer 15 needs to be set in consideration of that of the inner layer 13.

The inner layer 13, the intermediate layer 14, and the outer layer 15 may contain an appropriate filler such as an antistatic agent and a crosslinking agent, if necessary.

The above-mentioned semiconductive plastic endless belt comprises:
For example, it can be manufactured as follows. That is, first, a material for forming each of the layers 13 to 15 and a solvent thereof are appropriately blended, kneaded by a ball mill or the like, and then stirred to prepare each coating liquid. The concentration of the coating solution thus prepared is appropriately set according to the thickness of the layer. That is, the thickness of the layer is largely determined by adjusting the viscosity of the coating liquid, and is set by adjusting the viscosity. The viscosity is determined by the concentration of the coating liquid.

Next, as shown in FIG. 2, each of the above coating liquids is stored in a tank 16, a tank 17, and a tank 18, respectively. On the other hand, a metal shaft (for example, aluminum, stainless steel, etc.) 19 is prepared, and the shaft 19 is set upright.
First, it is repeatedly immersed in the coating liquid contained in the tank 16. Then, after repeating the immersion a predetermined number of times,
The shaft 19 is pulled up from the coating liquid. Then
The same operation is performed to form a three-layer structure. Next, after drying and removing the solvent, a heat treatment (for example, 60 to 150 ° C.)
× 60 minutes), and the shaft body 19 is removed.
The semiconductive plastic endless belt shown in FIG.

In addition to the above-mentioned manufacturing method, a multilayer extrusion molding method,
A semiconductive plastic endless belt can be obtained by a method such as a spray coating method and an inflation method.

The semiconductive plastic endless belt obtained in this manner is prepared so that the compounding ratio of the conductive filler in the inner layer and the compounding ratio of the conductive filler in the outer layer satisfy specific requirements. Since it is set, the contraction force on the inside becomes smaller than the contraction force on the outside, and no bending habit is formed. Therefore, the copy image of the electrophotographic copying machine incorporating this semiconductive plastic endless belt is
The image quality is high without causing defects such as white spots on the image.

The semiconductive plastic endless belt of the present invention is preferably set so that the bending angle measured by the following method (X) is in the range of 40 to 140 °. That is, if the endless belt is not within the above range, the endless belt may be bent when the belt is stretched over the roller. This is because there is a possibility that a defect such as white spots in an image may occur in a portion corresponding to the pitch.

(X) As shown in FIG. 3A, a sheet (length 150 mm × width 50 mm) 20 cut from an endless belt is first suspended from above a roller 21 having a diameter of 30 mm. After both ends are closed and fixed, the fixed portion is placed downward at 100 g / cm.
(500 g) was applied, and then left for 16 hours under the conditions of a temperature of 45 ° C. and a humidity of 90%. afterwards,
The load is removed, and then the sheet 20 is removed from the roller 21. After doing so, as shown in FIG.
It is assumed that the surface of the left and right sheet portions sandwiching the arc portion of the sheet 20 that is in contact with the roller 21 at the time of the suspension is extended upward, and the angle formed by the left and right virtual extension portions 23 Measure θ. This is defined as a bending angle.

The semiconductive plastic endless belt having the specific bending angle described above can be obtained by a method other than the above-described manufacturing method.

That is, for example, in the same manner as described above, a coating liquid for each layer is prepared and stored in each of the tanks 16-18. On the other hand, a metal shaft 19 is prepared, and the shaft 19 is set upright, and is first dipped repeatedly in a coating liquid for a material for forming the inner layer 13 which is the innermost layer contained in the tank 16. After repeating the immersion a predetermined number of times, the shaft 19 is pulled up from the coating solution. A liquid film of the coating liquid for the inner layer 13 is formed on the shaft 19. Next, the entire shaft with the liquid film is dried to evaporate the solvent in the liquid film to form the inner layer 13 as the innermost layer on the outer periphery of the shaft 19. Next, the shaft body with the inner layer is
After repeatedly immersing in the coating liquid contained in 7 and repeating the immersion a predetermined number of times, the shaft with the inner layer is pulled up from the coating liquid for forming the intermediate layer 14.
Then, in this state, after repeatedly immersing in the coating liquid contained in the tank 18 and repeating immersion a predetermined number of times, the shaft with the inner layer is pulled up from the coating liquid for the forming material of the outer layer 15, and the shaft is To form a three-layer structure on the outer periphery of. Next, after drying to remove the solvent from the intermediate layer 14 and the outer layer 15, a heat treatment (for example, 60 to 150 ° C. × 6)
0 minutes), and by extracting the shaft body 19,
The semiconductive plastic endless belt shown in FIG. 1 is obtained.

In the semiconductive plastic endless belt obtained by the above-described method, the blending ratio of the conductive filler in the inner layer and the conductive layer in the outer layer are determined as described above in the two layers extracted in order of thickness. It is not necessary to increase the content of the filler by a specific range. That is, even if the mixing ratio of the two layers is the same, according to this manufacturing method, the innermost layer is provided in advance, and then the outer layers are sequentially provided, so that the shrinking force of the inner layer can be suppressed. Therefore, it is possible to suppress a curl inward of the endless belt. This is a major feature of this manufacturing method.

In the semiconductive plastic endless belt, the total thickness of the inner layer 13, the intermediate layer 14, and the outer layer 15 is preferably 50 to 250 μm. More preferably, it is 100 to 200 μm. That is,
If the thickness is less than 50 μm, the strength may be insufficient, and if it exceeds 250 μm, the bending fatigue resistance may be poor.

The semiconductive plastic endless belt has an inner peripheral length of about 90 to 600 mm and a length of 10 to 10 mm.
Those having a thickness of about 0 to 500 mm are preferable. That is, if the shape is within the above range, the size becomes suitable for being incorporated in an electrophotographic copying machine.

Further, a semiconductive plastic endless belt
As a whole characteristic, its volume resistivity is 10⁶-10¹⁴Ω
-It is preferable to set to cm. More preferred
Is 10⁸-10¹²Ω · cm. That is, 10⁶
If it is less than Ω · cm, the charge will decay too quickly,
It may be necessary to increase¹⁴Ω · cm
Exceeds the charge decay too slow and requires a static elimination system
This is because In addition, the semiconductive
The surface resistivity of the endless belt is 10⁶-10¹⁴Ω
/ □ is preferably set. More preferred
Is 10⁸-10 ¹⁴Ω / □. That is, 10⁶Ω
If it is less than / □, the charge will decay too quickly and the capacity of the power supply will increase.
May need to be¹⁴Over Ω / □
Charge decay too slow and requires a static elimination system
This is because there is a fear.

The semiconductive plastic endless belt of the present invention is not limited to the above three-layer structure, but includes a silicone resin or the like on the surface of the outer layer 15 for the purpose of improving toner releasability. Provide a surface layer with the material to be
It may have a laminated structure of three or more layers. Further, the intermediate layer in the three-layer structure may be removed to form a two-layer structure.

The semiconductive plastic endless belt of the present invention is not limited to use as a transfer belt of an electrophotographic copying machine such as the above-described full-color copying machine.
It can also be used for a transfer belt of a monochromatic electrophotographic copying machine, which is not full color. Further, since the semiconductive plastic endless belt of the present invention can eliminate the bending habit when the belt is stretched over a roller, it can be used for all belts stretched over a roller.

Next, examples will be described together with comparative examples.

[0037]

Examples 1 to 4 and Comparative Examples 1 and 2 Each layer forming material and its solvent were mixed in the mixing ratio shown in Table 1 below, kneaded with a ball mill, and then stirred to prepare each coating liquid. did. Table 1 also shows the viscosities (measured by a B-type viscometer) of each coating solution. Next, each coating solution prepared as described above was stored in a separate tank (see FIG. 2). Then, in accordance with the above-described method, the inner layer, the intermediate layer, and the outer layer are sequentially laminated around the aluminum shaft body, dried, the solvent is removed, and then heat treatment (80 ° C. × 60 minutes) is performed. Thereby, each layer was formed. Next, the shaft body made of aluminum was extracted to obtain a desired semiconductive plastic endless belt. For the semiconductive plastic endless belt thus obtained, the thickness of each layer and the overall thickness, volume resistivity, surface resistivity, bending angle,
The image quality of the copied image was measured and evaluated, and the results were shown in Table 2 below.
It was shown to. In addition, each measurement was performed by the following method.

[Thickness] The thickness was measured using a micrometer.

[Volume resistivity and surface resistivity] JIS
According to the resistivity test method of K 6911, the applied voltage 100
The volume resistivity and surface resistivity at V were calculated.

[Bending Angle] The bending angle was measured by the method described above.

[Image quality of copied image] With the obtained semiconductive plastic endless belt assembled to the roller unit, it was left under high temperature and high humidity conditions (45 ° C. × 90%) for 3 days, and then this was subjected to full color It was incorporated into an electrophotographic copying machine (Pretail 500, manufactured by Ricoh Co., Ltd.), started up under normal temperature and normal humidity conditions (23 ° C. × 50%), and the obtained copied image was evaluated. In addition, those in which no disturbance was confirmed in the copied image were represented by ○, and those in which disturbance was confirmed were represented by x.

[0042]

[Table 1]

* 1: NEOFLON VT-100 (manufactured by Daikin Industries, Ltd.) * 2: Titanium black 13M (manufactured by Mitsubishi Materials Corporation) * 3: Toresin EF-30T (manufactured by Teikoku Chemical Industry Co., Ltd.) * 4: Conductive tin oxide T -1 (Mitsubishi Materials Corporation)

[0044]

[Table 2]

[0045]

Examples 5 to 7 The materials for forming the inner layer and the intermediate layer and their solvents were mixed in the mixing ratio shown in Table 3 below, kneaded with a ball mill, and then stirred to prepare each coating liquid. Table 3 also shows the viscosities (measured by a B-type viscometer) of each coating solution. Next, each coating solution prepared as described above was stored in a separate tank. Then, in the same manner as in Example 1, an inner layer and a layer serving as an intermediate layer are sequentially formed around the aluminum shaft body, dried, and the solvent is removed. Then, heat treatment (80 ° C. × 60 minutes) is performed. By performing this, an inner layer and an intermediate layer were formed. Then, the material for forming the outer layer was mixed in the same mixing ratio as shown in Table 3, and the outer layer was formed on the outer periphery of the intermediate layer using an extruder or the like. Next, the shaft body made of aluminum was extracted to obtain a desired semiconductive plastic endless belt. For the semiconductive plastic endless belt thus obtained, the thickness of each layer and the overall thickness, volume resistivity, surface resistivity, bending angle, and image quality of the copied image were measured and evaluated in the same manner as in Example 1. The results are shown in Table 4 below.

[0046]

[Table 3]

* 1: NEOFLON VT-100 (manufactured by Daikin Industries, Ltd.) * 2: Titanium black 13M (manufactured by Mitsubishi Materials Corporation) * 3: Toresin EF-30T (manufactured by Teikoku Chemical Industry Co., Ltd.) * 4: Conductive tin oxide T -1 (Mitsubishi Materials) * 5: Europion E2000 (Mitsubishi Gas Chemical) * 6: Zenoi 1731 (GE Plastics) * 7: Victrex 450G (Mitsui Toatsu Chemical) * 8: Shu Black N330 (Showa Cabot)

[0048]

[Table 4]

In all of the above Examples 1 to 7, since the compounding ratio of the conductive filler in the inner layer is larger than the compounding ratio of the conductive filler in the outer layer, the endless belt does not bend.
Therefore, when this endless belt is incorporated in an electrophotographic copying machine and used, the obtained copied image is of high image quality without defects such as white spots corresponding to the roll pitch. On the other hand, in the products of Comparative Examples 1 and 2, since the compounding ratio of the conductive filler in the inner layer is not larger than the compounding ratio of the conductive filler in the outer layer, the endless belt is bent. Therefore, the obtained copied image has a defect such as white spots in a portion corresponding to the roll pitch.

[0050]

Examples 8 to 10 Each layer forming material and its solvent shown in Table 5 below were prepared, blended in the mixing ratio shown in the same table, kneaded by a ball mill, and then stirred to obtain each coating. A liquid was prepared. Table 5 also shows the viscosities (measured by a B-type viscometer) of each coating solution. Next, each coating solution prepared as described above was stored in a separate tank (see FIG. 2). Then, a liquid film serving as an inner layer was formed around the aluminum shaft, and after drying and removing the solvent, a heat treatment (80 ° C. × 60 minutes) was performed to form an inner layer. Then, a liquid film serving as an intermediate layer and an outer layer is sequentially formed around the aluminum shaft body with the inner layer, dried, and the solvent is removed. Then, a heat treatment (80 ° C. × 60 minutes) is performed. Each layer including the above inner layer was formed on the outer periphery of. Then, pull out the aluminum shaft,
The intended semiconductive plastic endless belt was obtained. For the semiconductive plastic endless belt thus obtained, the thickness of each layer and the overall thickness, volume resistivity, surface resistivity, bending angle, and image quality of the copied image were measured and evaluated in the same manner as in Example 1. The results are shown in Table 6 below.

[0051]

[Table 5]

* 1: NEOFLON VT-100 (manufactured by Daikin Industries, Ltd.) * 2: Titanium Black 13M (manufactured by Mitsubishi Materials Corporation) * 3: Toresin EF-30T (manufactured by Teikoku Chemical Industry Co., Ltd.) * 4: Conductive tin oxide T -1 (Mitsubishi Materials Corporation)

[0053]

[Table 6]

In all of the products of Examples 8 to 10, the inner layer, which is the innermost layer, is formed in advance, and then the intermediate layer and the outer layer are sequentially formed. Therefore, the endless belt does not have a bending tendency. Therefore, when this endless belt is incorporated in an electrophotographic copying machine and used, the obtained copied image is of high image quality without defects such as white spots corresponding to the roll pitch.

[0055]

As described above, the semiconductive plastic endless belt of the present invention is a multi-layer endless belt, and in the two layers extracted in order of thickness from among the above-mentioned multi-layers, the material of the inner layer forming material Since the compounding ratio of the conductive filler is set to be larger than the compounding ratio of the conductive filler in the forming material of the outer layer by a specific range, the semiconductive plastic endless belt does not have a bending habit. . Therefore, when the endless belt is used as a transfer belt of an electrophotographic copying machine or the like, the obtained copied image has a very high image quality, and the excellent image quality can be obtained for a long period of time.

In particular, when the bending angle of the semiconductive plastic endless belt is set in a specific range, it can be used in an extremely good condition when used in an electrophotographic copying machine or the like. In addition, the obtained copied image is further improved.

Further, in the method for producing the semiconductive plastic endless belt, the innermost layer is provided in advance, and then the layers other than the innermost layer are sequentially formed, whereby the inward shrinkage of the entire endless belt can be suppressed. Therefore, the endless belt obtained by this manufacturing method is unlikely to bend. Therefore, when this endless belt is used as a transfer belt of an electrophotographic copying machine or the like, the obtained copied image has a very high image quality, and the excellent image quality can be obtained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a semiconductive plastic endless belt of the present invention.

FIG. 2 is an explanatory diagram showing an example of a method for producing a semiconductive plastic endless belt of the present invention.

FIG. 3A is an explanatory diagram illustrating a method of measuring a bending angle of an endless belt, and FIG. 3B is an explanatory diagram illustrating a bending angle to be measured.

FIG. 4 is an explanatory diagram showing a copying mechanism of the electrophotographic copying machine.

FIG. 5 is an explanatory diagram showing a state where an endless belt is stretched over rollers.

[Explanation of symbols]

 13 inner layer 14 middle layer 15 outer layer

Claims (3)

[Claims] 1. An endless belt comprising a plurality of layers, wherein two layers extracted in order of thickness from among the plurality of layers are set so as to satisfy the following requirements (A) and (B). And a semiconductive plastic endless belt. (A) Of the two layers, at least the inner layer contains a conductive filler. (B) Among the two layers, the blending ratio of the conductive filler to the whole forming material of the inner layer is 3 to 27% by weight larger than the blending ratio of the conductive filler to the whole forming material of the outer layer. 2. The semiconductive plastic endless belt according to claim 1, wherein a bending angle measured by the following method (X) is set in a range of 40 to 140 °. (X) Sheet cut from endless belt (length 150m
m × width 50 mm) is suspended from above a roller having a diameter of 30 mm, and the hanging both ends of the sheet are closed together and fixed.
And then left for 16 hours under the conditions of a temperature of 45 ° C. and a humidity of 90%, then remove the load, remove the sheet from the roller, and make the sheet in contact with the roller at the time of the suspension arc-shaped. It is assumed that the surface of the left and right seat parts sandwiching this center part has been extended upward,
The angle made by the left and right virtual extensions. 3. A method for producing a multi-layer endless belt provided with at least one layer containing a conductive filler,
Along with preparing the shaft body, a solvent solution of the forming material of each layer in the multilayer is prepared for each layer, and in a state where the shaft body is vertical, the solvent solution for the forming material of the innermost layer of the multilayer is prepared. A liquid film composed of a solvent solution of the innermost layer forming material is formed on the outer periphery of the shaft by repeatedly immersing and pulling up, and then the solvent is volatilized from the liquid film through a drying step to evaporate the innermost layer. The shaft body with the innermost layer is sequentially immersed and pulled up in a solvent solution of a material for forming a layer other than the innermost layer, and a liquid film of each layer is formed by lamination. And forming a multilayer including the innermost layer on the outer periphery of the shaft body, and then extracting the shaft body.