JP2000039777A - Semiconducting plastic belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconducting plastic belt which realizes a high quality copied image without causing voids. SOLUTION: This belt is an endless belt having at least a developer supporting layer 16, and the molecular structure of the surface of the developer supporting layer 16 satisfies the following conditions (X) and (Y). (X) Fluorine atoms are present by 35 to 45 atom.% to the total atoms present on the surface of the developer supporting layer 16. (Y) Oxygen atoms are present by 6 to 11 atom.% to the whole atoms present on the surface of the developer supporting layer 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive plastic belt used as a transfer intermediate for copying a toner image on a photoreceptor in an apparatus employing electrophotography such as a full-color copying machine.

[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 image is temporarily copied to a transfer intermediate. After that, a process of transferring the image to copy paper is adopted.

An 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 a static image 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
Supplies a developer to form a toner image. An endless belt 6 which is a transfer intermediate is pressed against the photosensitive drum 1 via a primary transfer roller 7 below the photosensitive drum 1, and a toner image developed on the photosensitive drum 1 is The repetitive running of the endless belt 6 in both the forward and reverse directions causes the color to be transferred to the surface of the endless belt 6 in the order of each color. As the endless belt 6 travels, the toner image is transferred onto the copy paper 9 sandwiched between the endless belt 6 and the secondary transfer roller 8. Note that the developer 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 developer remaining on the surface of the photosensitive drum 1 after the primary transfer is collected by the cleaning device 11, and thereafter, the surface of the photosensitive drum 1 is discharged by the eraser lamp 12.

In the above-described electrophotographic copying machine, in order to improve the quality of a copied image, the toner image formed on the photosensitive drum 1 or the endless belt 6 is uniformly transferred with a transfer efficiency of 90% or more. It is known that it is necessary to: For this reason, the endless belt 6 is strongly required to have toner filming resistance, and various attempts have been made. For example, an organic fluorine compound is supplied to the surface of the endless belt 6, a wetting control agent is added to a material for forming the endless belt 6, a protective film having lubricity such as zinc stearate is formed on the surface of the endless belt 6, silicone Controlling the surface roughness of the surface of the endless belt 6 using rubber;
Attempts have been made to physically grind the surface of the endless belt 6.

[0005]

However, when image formation is performed using the endless belt 6 as a transfer intermediate of a full-color copying machine, a part of the developer remains on the surface of the transfer intermediate, and a copy image is formed. However, there is a problem that a phenomenon in which the developer is not loaded, that is, a so-called hollow portion occurs, and a copied image that sufficiently satisfies the recent demand for higher image quality has not been obtained.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductive plastic belt which does not cause a hollow portion and can realize high quality of a copied image.

[0007]

In order to achieve the above object, a semiconductive plastic belt according to the present invention is an endless belt provided with at least a developer carrying layer, wherein a molecular surface of the developer carrying layer is provided. The structure has the following requirements (X),
(Y) is satisfied. (X) Fluorine atoms are present in an amount of 35 to 45 atom% based on all atoms existing on the surface of the developer carrying layer. (Y) Oxygen atoms are present in an amount of 6 to 11 atom% with respect to all atoms existing on the surface of the developer carrying layer.

That is, the present inventors have conducted a series of studies in order to obtain a semiconductive plastic belt capable of obtaining a high-quality copied image without a hollow portion. In the process, with respect to the endless belt 6, physical factors such as compatibility of the forming material and surface smoothness, and a local electrostatic force (Coulomb force) generated between the photosensitive drum 1, the endless belt 6 and the like and the developer. It has been found that when the electrical factors such as (1) and (2) satisfy certain conditions, the toner releasability is improved. Therefore,
In consideration of this knowledge, as a result of further research, it was found that the intended purpose can be achieved by providing a special developer carrying layer in which fluorine atoms and oxygen atoms are present at specific ratios, respectively. The invention has been reached.

In the present invention, "semiconductive" means that the measured value of the volume resistivity measured at an applied voltage of 100 V is 10 ⁶ to 10 ¹⁴ in accordance with the resistivity test method of JIS K 6911. It is within the range of Ω · cm. Further, the “developer” is for visualizing an electrostatic latent image, and is a general term including a toner that is an image forming substance and a substance other than the toner that is blended as needed. is there. Further, “atom%” is a unit indicating how many predetermined atoms are present when the total number of atoms existing on the surface of the developer carrying layer is 100.

[0010]

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

The semiconductive plastic belt of the present invention is an endless belt, for example, as shown in FIG.
It has a four-layer structure of an inner layer 13, an intermediate layer 14 adjacent thereto, an outer layer 15 adjacent to the intermediate layer 14, and a developer carrying layer 16 adjacent to the outer layer 15.

As a material for forming the inner layer 13, a fluorine resin, a vinyl chloride resin, an ABS resin, polymethyl methacrylate (PMMA), polycarbonate (PC),
Examples include polyethylene terephthalate (PET), acrylic rubber, and polyurethane (PU). These may be used alone or in combination of two or more. Especially, a fluororesin is preferable.

As the fluororesin, vinylidene fluoride-ethylene tetrafluoride copolymer [hereinafter referred to as “Poly (Vd
F-TFE)]], ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro Examples thereof include an alkyl vinyl ether copolymer (PFA). Above all, Poly (V
dF-TFE) is preferred. Examples of the solvent for the fluororesin include methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, ethyl acetate, tetrahydrofuran and the like. These may be used alone or in combination of two or more.

The material for forming the intermediate layer 14 formed adjacent to the inner layer 13 is not particularly limited, but may be N-methoxymethylated nylon, nylon 1
2. Polyamide resins such as copolymerized nylon.
Among them, N-methoxymethylated nylon is preferred.
Examples of the solvent for the polyamide resin include a single solvent such as methanol and ethanol or a mixed solvent obtained by mixing such a single solvent with water, toluene, and the like, 1-propanol, 2-propanol, and the like.

The material for forming the outer layer 15 formed adjacent to the intermediate layer 14 is not particularly limited, but may be the same material as that used for the inner layer 13.

The material for forming the developer carrying layer 16 formed adjacent to the outer layer 15 is not particularly limited as long as it satisfies requirements (X) and (Y) described later. Instead, for example, a fluorinated acrylic resin represented by the following general formula (1) obtained by polymerizing an acrylic monomer and a fluorinated acrylic monomer by a conventionally known method can be exemplified.

[0017]

Embedded image

In the general formula (1), R ¹ is a monovalent substituent and is not particularly limited as long as it can form an acrylic monomer. Specifically, a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group,
2,2-dimethylpropyl group, octyl group, dodecyl group, cyclohexyl group, phenyl group, 2-tert-butylphenyl group, methoxyphenyl group, 4-methoxyphenyl group, 2-methoxycarbonylphenyl group, 2-ethoxycarbonylphenyl Group, 2-chlorophenyl group,
4-chlorophenyl group, 4-cyanophenyl group, p-tolyl group, benzyl group, 2-cyanobenzyl group, 2-cyanoethyl group, 2-hydroxyethyl group, hydroxypropyl group, hydroxybutyl group, 3-oxabutyl group, 2
-A naphthyl group, an isobornyl group, a glycidyl group and the like.

In the above general formula (1), Rf is a fluorinated alkyl group, and a perfluoroalkyl group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms, or a part of hydrogen atoms of the alkyl group are fluorine atoms. Any of a partially fluorinated alkyl group substituted with an atom may be used.
Among them, a perfluoroalkyl group having 1 to 20 carbon atoms is preferable.

The specific fluorinated acrylic resin preferably has a number average molecular weight in the range of 1 × 10 ³ to 1 × 10 ⁶ . Above all, 1 × 10 ⁴ -5 × 10
The range is ⁵ . In addition, the said number average molecular weight is the number average molecular weight of polystyrene conversion by the gel permeation chromatography (GPC) method.

Examples of the solvent for the specific fluorinated acrylic resin include ketones such as acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone; esters such as methyl acetate and butyl acetate; polar solvents such as dimethyl formamide and dimethyl sulfoxide; Halogen solvents such as 1,1,1-trichloroethane and chloroform, ethers such as tetrahydrofuran and dioxane, aromatics such as benzene, toluene and xylene, and fluorine such as perfluorooctane and perfluorotri-N-butylamine And inert liquids. Of these, acetone is preferred.

In addition to the above specific fluorinated acrylic resin, ethylene and a fluorinated acrylic monomer are
Examples thereof include an ethylene-fluorinated acrylic copolymer represented by the following general formula (2), which is obtained by polymerizing by a conventionally known method.

[0023]

Embedded image

In the above formula (2), Rf is a fluorinated acrylic monomer, and examples thereof include the same type as the fluorinated alkyl group in the above formula (1).

The number average molecular weight of the specific fluorinated acrylic resin is preferably set in the range of 1 × 10 ³ to 1 × 10 ⁶ . Above all, 1 × 10 ⁴ -5 × 10
The range is ⁵ .

Further, ethylene-acryl represented by the following general formula (3) obtained by polymerizing ethylene, an acrylic monomer and a fluorinated acrylic monomer by a conventionally known method. -A fluorinated acrylic terpolymer can also be exemplified.

[0027]

Embedded image

In the general formula (3), R ¹ is a monovalent substituent, and Rf is a fluorinated acrylic monomer. The same type as the group can be exemplified.

The number average molecular weight of the specific ethylene-acryl-fluorinated acrylic terpolymer is from 1 × 10 ³ to 1
It is preferably set to a range of × 10 ⁶ . Especially, it is in the range of 1 × 10 ^{4 to} 5 × 10 ⁵ .

The inner layer 13, the intermediate layer 14, and the outer layer 1
The material for forming the developer layer 5 and the developer carrying layer 16 may contain a conductive agent, an antistatic agent, a cross-linking agent, and the like, if necessary. However, in order to prevent an abnormal image, the developer carrying layer 1
Preferably, No. 6 does not contain a conductive agent.

As the conductive agent, aluminum powder,
Metal powder such as stainless steel powder, c-ZnO, c-TiO
₂ , conductive metal oxides such as c-Fe ₃ O ₄ and c-SnO ₂ , graphite, conductive powders such as carbon black,
Quaternary ammonium salts, phosphate esters, sulfonates,
Ionic conductive agents such as aliphatic polyhydric alcohols and aliphatic alcohol sulfate salts; These may be used alone or in combination of two or more. Above all,
From the viewpoint of dispersibility, c-TiO ₂ and c-SnO ₂ are preferred. Note that “c−” means having conductivity.

The semiconductive plastic belt of the present invention can be manufactured, for example, as follows. That is, first, a synthetic resin as a material for forming each of the layers 13 to 16 and a solvent thereof, and as necessary, a conductive agent and the like,
Each coating solution is prepared by appropriately mixing and dispersing with a sand mill or the like.

Next, as shown in FIG. 2, the respective coating liquids are respectively stored in tanks 17, 18, 19 and 20. On the other hand, a metal shaft (for example, aluminum,
A shaft 21 is prepared vertically, and is dipped repeatedly in the coating liquid for forming the inner layer 13 housed in the tank 17. After repeating the immersion a predetermined number of times, the shaft 21 is removed from the coating solution.
Pull up. Next, using a coating liquid for forming the intermediate layer 14, a coating liquid for forming the outer layer 15, and a coating liquid for forming the developer carrying layer 16, the same operation is performed in this order to form a resin liquid film having four layers. I do. Then, after drying the resin liquid film and removing the solvent, a heat treatment (for example, 60 to 150 ° C. × 60 minutes) is performed, and the shaft 21 is extracted to obtain the semiconductive plastic belt shown in FIG. be able to.

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

The semiconductive plastic belt thus obtained has a molecular structure on the surface of the developer carrying layer 16.
The following requirements (X) and (Y) must be satisfied. (X) Fluorine atoms are present in an amount of 35 to 45 atom% based on all atoms existing on the surface of the developer carrying layer 16. (Y) Oxygen atoms are present in an amount of 6 to 11 atom% with respect to all atoms existing on the surface of the developer carrying layer 16.

The amount of the fluorine atoms and the number of the oxygen atoms can be determined according to the X-ray photoelectron spectroscopy (ESCA analysis method) of JIS H0211.
6 is a value calculated by analyzing the surface of No. 6 and examining the chemical bonding state of the surface. That is, the number of all atoms (α), the number of fluorine atoms (β), and the number of oxygen atoms (γ) present on the surface of the developer carrying layer are counted from the result of the above-mentioned Esca analysis, and the following formula (1) is obtained. ).

[0037]

Abundance (atom%) = [(β or γ) / α] × 100 (1)

As described above, the abundance of the fluorine atom and the abundance of the oxygen atom are specified in the specific ranges. This is because the toner image cannot be transferred with good reproducibility.

It is preferable that fluorine atoms and oxygen atoms are uniformly distributed on the surface of the developer carrying layer 16. Thereby, image unevenness can be prevented, and higher image quality can be further realized.

The semiconductive plastic belt is an endless belt composed of multiple layers including a developer carrying layer, and the molecular structure of the surface of the developer carrying layer satisfies specific requirements. For this reason, it is possible to prevent toner filming, which adversely affects the high quality of the copied image, and to carry the developer in an orderly manner, so that the toner image can be faithfully transferred. Therefore, high quality of the copied image can be realized.

In the semiconductive plastic belt, the total thickness of the inner layer 13, the intermediate layer 14, the outer layer 15, and the developer carrying layer 16 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 belt has an inner peripheral length of 90 to 600 mm and a width of 100 to 500 mm.
mm is preferable. With these dimensions,
The reason for this is that the size becomes appropriate for being incorporated in an electrophotographic copying machine or the like.

The semiconductive plastic belt of the present invention comprises:
The structure is not necessarily limited to the four-layer structure, but may be a single-layer structure or a stacked structure of two or more layers, and the molecular structure on the surface may satisfy the above requirements (X) and (Y).

Although the semiconductive plastic belt of the present invention is mainly used as a transfer intermediate for a full-color copying machine or the like, it can also be used as a transfer intermediate for a non-full-color, single-color electrophotographic copying machine or the like.

Next, examples will be described together with comparative examples.

First, prior to Examples and Comparative Examples, a coating liquid for forming an inner layer, a coating liquid for forming an intermediate layer, a coating liquid for forming an outer layer, and a coating liquid for forming a developer carrying layer were prepared.

[Preparation of Coating Solution for Forming Inner Layer] First, 100 parts by weight of Poly (VdF-TFE) and 36 parts by weight of c-TiO ₂ were prepared. Then P
After dissolving poly (VdF-TFE) in 400 parts by weight of acetone, the above-mentioned c-TiO ₂ was added, the mixture was stirred and dispersed by a sand mill, and a predetermined amount of a phosphate ester-based antistatic agent was added thereto to form an inner layer. A coating solution was prepared.

[Preparation of Coating Solution for Formation of Intermediate Layer] Subsequently, 100 parts by weight of N-methoxymethylated nylon and 64 parts by weight of c-SnO ₂ were prepared. Then N
After dissolving methoxymethylated nylon in 480 parts by weight of a mixed solvent of methanol / water (methanol / water = 3/1), the above c-SnO ₂ was added, and the mixture was stirred with a sand mill.
By dispersing, a coating liquid for forming an intermediate layer was prepared.

[Preparation of Coating Solution for Forming Outer Layer] Next, the same coating solution for forming the inner layer was used as the coating solution for forming the outer layer.

[Preparation of Coating Solution for Forming Developer-Supporting Layer] The materials shown in Tables 1 and 2 below are blended in the proportions shown in the same table, stirred by a sand mill, and dispersed to form a developer. A coating solution for forming a support layer was prepared.

[0051]

Examples 1 to 5 and Comparative Examples 1 to 7 First, the coating liquids for forming the respective layers prepared as described above were respectively housed in separate tanks (see FIG. 2). Then, in accordance with the above-described method, a resin liquid film serving as an inner layer, an intermediate layer, an outer layer, and a developer carrying layer is sequentially formed around the aluminum shaft, dried, and the solvent is removed. × 60 minutes) to form each layer. Then, the shaft was removed to produce an endless belt having four layers.

With respect to the endless belt thus obtained, the amount of fluorine atoms (F) and the amount of oxygen atoms (O) on the surface of the developer carrying layer were measured.
And Table 2 together. The image quality of the copied image was evaluated, and the results are shown in Tables 3 and 4 below. In addition, each measuring method is as follows.

[F, O] Esca Analyzer (5600C
i, manufactured by ULVAC-PHI). Then, as described above, the total number of atoms, the number of fluorine atoms, and the number of oxygen atoms were counted, and the F amount and the O amount were calculated.

[Evaluation of Image Quality] The obtained endless belt was assembled in a full-color copying machine, and this was subjected to normal temperature and normal humidity environment (23 ° C.).
× 50%), and the image quality of the copied image obtained after copying 20,000 sheets was evaluated. Then, the case where no void was confirmed in the copied image was displayed as ○, and the case where it was confirmed was displayed as x. In addition, abnormal images other than hollow images (image unevenness, etc.)
Were not confirmed, and those that could be confirmed were indicated by x.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 4]

In all of the above examples, the F amount on the surface of the developer carrying layer is within a specific range, and the O amount is within a specific range. For this reason, when copying is performed by being incorporated in a full-color copying machine, a blank image and other abnormal images do not occur, and the copied image has high image quality. On the other hand, in all of the above comparative example products, at least one of the F amount and the O amount is out of the specific range, so that the hollow portion occurs. Moreover, the comparative examples 3, 6, and 7 also have abnormal images other than the voids. Therefore, if both the F amount and the O amount are not within the specific ranges, it is understood that the hollowing out cannot be prevented and a high-quality copy image cannot be obtained.

[0060]

As described above, the semiconductive plastic belt of the present invention is an endless belt provided with at least a developer carrying layer, and the surface of the developer carrying layer has
Fluorine atoms and oxygen atoms are present at a specific ratio. Therefore, when used as a transfer intermediate of an electrophotographic copying machine such as a full-color copying machine, there is an excellent effect that a high-quality copied image can be obtained without generating an abnormal image such as a hollow image.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view showing an example of a method for producing the semiconductive plastic belt.

FIG. 3 is a configuration diagram illustrating a copying mechanism of the electrophotographic copying machine.

[Explanation of symbols]

 16 Developer carrying layer

Claims (1)

[Claims] 1. An endless belt having at least a developer carrying layer, wherein the molecular structure of the surface of the developer carrying layer satisfies the following requirements (X) and (Y). Conductive plastic belt. (X) Fluorine atoms are present in an amount of 35 to 45 atom% based on all atoms existing on the surface of the developer carrying layer. (Y) Oxygen atoms are present in an amount of 6 to 11 atom% with respect to all atoms existing on the surface of the developer carrying layer.