JPH0199072A - Roll - Google Patents

Abstract

PURPOSE:To provide uniform electrical characteristics having reproducibility to the titled roll by forming the surface layer of a conductive roll of a conductive resin layer formed by dispersing and introducing a heterocyclic 5-membered ring polymer into a thermosetting resin matrix by utilizing a solvent. CONSTITUTION:The conductive resin layer 11 is formed directly or via an adhesive agent layer on the outside peripheral face of a metallic shaft 1. For example, the solvent which can dissolved both the thermosetting resin prepolymer and the heterocyclic 5-membered ring polymer is prepd. After the thermosetting resin prepolymer is dissolved in such solvent, the heterocyclic 5-membered ring compd. such as pyrrole is dissolved in the soln. and an oxidizing agent is dropped thereto to prepare the resin liquid polymerized with the heterocyclic 5-membered ring compd. in the thermosetting resin prepolymer soln. This resin liquid is applied on the outside peripheral face of the metallic shaft 10 and is cured by heating. Application of such resin liquid is adequately executed by using a dipping system, by which the uniform electrical conductivity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a conductive roll used as a developer component of an electrophotographic copying machine.

[Conventional technology]

2. Description of the Related Art Conductive rolls used as developing rolls of electrophotographic copying machines and the like are generally constructed from a cylindrical core metal and a conductive resin layer formed on its outer peripheral surface.

These conductive rolls, as mentioned above, are used in electrophotographic copying machines, such as triboelectric electrophotographic copying machines. Copying by this type of friction type electrophotographic copying machine is performed as follows. That is, as shown in Figure 4,
By uniformly charging the outer peripheral surface of the photosensitive drum 4 with a photoconductor surface layer and then exposing the outer peripheral surface to light through the image to be copied, an electrostatic latent image is formed on the outer peripheral surface. Form. Next, toner 8 is supplied from a toner supply device 7 between the friction roll 5 and the developing roll 6, and the toner 8 is supplied between the friction roll 5 and the developing roll 6.
The toner 8 is made to adhere to the outer circumferential surface of the developing roll 6 in a charged state by the frictional force, and the toner 8 is evened out by the layer forming blade 9. Then, the toner 8 is caused to fly against the electrostatic latent image on the photosensitive drum 4 by electric attraction and adhere to the electrostatic latent image to form a toner image, which is transferred to the copy paper 3 and fixed.

Copying is performed in this manner.

Therefore, if the electrical characteristics on the surface of the conductive roll used as the developing roll 6 are uneven depending on the part, the toner 8 will adhere unevenly and the quality of the obtained copy image will deteriorate. Strict requirements are placed on the uniformity of electrical properties on the surface of the rubber roll.

The electrical characteristics on the surface of the conductive roll are characterized by the conductive resin layer 11 (see FIG. 1) formed on the outer peripheral surface of the metal shaft 10 of the conductive roll.

This conductive resin layer 11 is usually made of molding resin powder,
After dispersing conductive substances such as metal particles, metal oxide powder, graphite, carbon black, etc. in various shapes (fibrous, flake, ribbon, powder, etc.), it is formed into a cylindrical shape by extrusion molding or molding. It can be obtained by molding into. The more uniform the dispersion state of the conductive particles in the resin matrix, the more uniform the electrical properties of the conductive resin layer 11 can be obtained.

[Problem that the invention seeks to solve]

However, it is difficult to make the dispersion state of the conductive material particles uniform in the resin matrix. This method has the disadvantage that careful attention is required in the manufacturing process and in the molding process of the conductive resin layer, resulting in a very high product cost.

The present invention was made in view of the above circumstances, and an object thereof is to provide a conductive roll having uniform and reproducible electrical characteristics.

[Means for solving problems]

In order to achieve the above object, the conductive roll of the present invention is made of a conductive resin composition mainly consisting of a dispersion in which a five-membered heterocyclic polymer is uniformly dispersed in a thermosetting resin matrix. The surface layer is formed of a synthetic resin layer.

That is, in order to obtain a conductive roll with uniform conductivity and high reproducibility, the present inventors believe that in order to obtain a conductive roll with uniform conductivity and high reproducibility, the conductive material and the resin that will become the matrix are both made of the same material, rather than simply mixing the conductive materials. The idea was that if the conductive material was dissolved in a solvent and a conductive resin layer was formed from this resin liquid, the conductive material would be uniformly dispersed in the matrix resin and a desirable result could be obtained. As a result of a series of research on the combination of resin and conductive material that constitutes the resin matrix, we used a 5-membered heterocyclic polymer as the conductive material, and discovered that the complex 5-membered ring polymer
When a thermosetting resin prepolymer that is soluble in a solvent that dissolves the membered ring polymer is used for the matrix composition, and both are mixed in a solution state and then cured to form the surface layer of the conductive roll, The inventors have discovered that it is possible to easily obtain a conductive roll of excellent quality that has uniform conductivity and is unaffected by temperature, etc., and has thus arrived at this invention. In addition, in this invention, "consisting mainly" is used to include the case where the conductive resin composition consists only of the above-mentioned dispersion.

Next, this invention will be explained in detail.

The conductive roll of the present invention can be applied directly to the outer circumferential surface of a metal shaft 10 or with an adhesive layer (as shown in FIG. 1).
A conductive resin layer 11 is formed with a conductive resin layer 11 interposed therebetween (not shown).

The conductive resin layer 11 is obtained as follows.

That is, for example, a thermosetting resin prepolymer and a complex
Prepare a solvent that can dissolve both membered ring polymers, dissolve the thermosetting resin prepolymer in the solvent, dissolve a 5-membered heterocyclic compound such as pyrrole in the solution, and then drop an oxidizing agent. A resin liquid is prepared by polymerizing a 5-membered heterocyclic compound in a thermosetting resin prepolymer solution to form a 5-membered heterocyclic polymer (in 5-itu method). Next, the resin liquid is applied to the outer peripheral surface of the metal shaft 10 and cured by heating. Thus, in this invention, the term 5-membered heterocyclic compound refers to a 5-membered ring compound such as pyrrole, and the term 5-membered heterocyclic polymer refers to a polymer thereof.

Note that in the above resin liquid, a five-membered heterocyclic polymer obtained by polymerization of a five-membered heterocyclic compound and a thermosetting resin prepolymer matrix are uniformly dispersed in the same solvent.
In some cases, a part of the five-membered heterocyclic compound as a raw material may remain as it is without polymerizing. However, the amount can be suppressed to none or to a very small amount by considering the polymerization conditions.

It is preferable to apply the resin liquid to the metal shaft 1o using a dip method. More specifically, a resin liquid containing the above five-membered heterocyclic polymer and a thermosetting resin prepolymer is stored as a dip liquid in a tank 12 as shown in FIG. A resin liquid film is formed on the outer peripheral surface of the metal shaft 10 by standing the metal shaft 10 vertically and repeatedly dipping it into the resin liquid in the tank 12. At this time, the lifting speed, the number of lifting and lowering,
Conditions such as drying time are such that the liquid film of the resin liquid film is 10 to 5
It is preferable to set the optimum conditions so that it falls within the range of 00 μm. Then, by drying this at a temperature of 25 to 80°C for 0.5 to 4 hours, the solvent is removed and the resin liquid film is solidified, and further heated to 100 to 150°C to remove the liquid derived from the resin liquid. The conductive resin layer 11 can be obtained by polymerizing and curing the thermosetting resin prepolymer. The conductive resin layer 11 is formed using a resin liquid obtained by polymerizing a five-membered heterocyclic compound in a uniform solution of a matrix resin prepolymer, and has uniform conductivity. That is, in the matrix resin solution, the five-membered heterocyclic compound is uniformly distributed, unlike in the case of powder mixture. Therefore, when the five-membered heterocyclic compound in this state is polymerized, a resin liquid in which the five-membered heterocyclic polymer is uniformly distributed can be obtained. Since the conductive resin layer 11 is formed by curing such a resin liquid, the conductivity is uniform and does not vary.

Incidentally, in the case where the conductive resin layer 11 is made thick, the conductive roll of the present invention can be obtained as a sleeve-shaped resin molded product in the following manner, without using the dip method described above. That is, a resin liquid was prepared in the same manner as above,
The solvent of this resin liquid is removed by drying and solidified into a sheet or block. A powdered resin is obtained by pulverizing this solid material and kneading it with a roll or the like. Of course, additives such as fillers may be added as necessary at the mixing stage. Then, the powdered resin is formed into pellets by tabletting or the like, and then formed into a cylindrical shape by ordinary extrusion molding or die molding. The cylindrical resin molded product may be used as it is as a conductive roll, or may be used by being fitted onto a metal shaft for a conductive roll.

Examples of the 5-membered heterocyclic compound used in this invention include pyrroles, thiophenes, selenophenes, tellurophenes, etc. as shown below, among which pyrrole,
N-substituted pyrrole, 3-substituted pyrrole, 4-substituted pyrrole, 3,4-disubstituted pyrrole, etc. have excellent reactivity and are suitable.

As a solvent that dissolves both the 5-membered heterocyclic polymer obtained from the 5-membered heterocyclic compound and the matrix resin,
Water, alcohol and 3 ethers.

Examples include ketones. These may be used alone or in combination.

As the oxidizing agent which is a polymerization catalyst for the above hetero5R ring compound, inorganic acids such as sulfuric acid, nitric acid, chlorosulfonic acid, A/2
．． Examples include chlorides of metals such as Fe, Cu, and Pt (so-called "Lewis acids"), metal compounds such as sulfates and nitrates, benzoquinone, diazonium salts, and organic acids such as succinic acid and citric acid, which can be used alone or in combination. It is used as Note that these oxidizing agents also act as doping agents for conductivity. 'The thermosetting resin prepolymer to be dissolved in a solvent together with the 5-membered heterocyclic polymer obtained from the 5-membered heterocyclic compound is assumed to be soluble in the above-mentioned solvent. (-0-), amide group (-CO
Examples include thermosetting resin prepolymers having functional groups such as NH).

Specifically, phenolic resin prepolymers, urea resin prepolymers, benzoguanamine resin prepolymers, etc. can be used alone or in combination.

Note that among these, it is particularly suitable to use a phenol resin prepolymer (number average molecular weight of about 500 to 2,000). The above-mentioned phenolic resin prepolymer may be either a phenol novolac type or a talesol novolac type.

When preparing a resin solution using these raw materials according to the method described above, the amount of the 5-membered heterocyclic compound such as pyrrole is adjusted to the total weight A of the 5-membered heterocyclic compound, the thermosetting resin prepolymer, and the oxidizing agent. It is preferable to set the amount of the thermosetting resin prepolymer to 0.5 to 90% by weight (hereinafter referred to as "%"), and it is preferable to set the amount of the thermosetting resin prepolymer to 10 to 99% with respect to A. be. In addition, the amount of the oxidizing agent, which is a polymerization catalyst, is A
It is preferable to set the amount to be 0.5 to 90% based on the weight of the five-membered heterocyclic compound and not to exceed five times the weight of the five-membered heterocyclic compound. Further, the polymerization reaction temperature when the oxidizing agent is added dropwise to perform the polymerization reaction of the five-membered heterocyclic compound is preferably set to 0 to 80'C.

Conductive resin layer 1 of the conductive roll obtained in this way
No. 1 (see FIG. 1) has a five-membered heterocyclic polymer uniformly dispersed at the molecular level in a thermosetting resin matrix.

Therefore, this conductive roll exhibits uniform conductivity at any location. The electrical conductivity can be varied over a wide range of 10' to 1012 Ωcm by changing the amount of the five-membered heterocyclic compound added, the amount of the oxidizing agent added, the reaction temperature during polymerization, the reaction time, etc. Can be easily controlled within.

Note that the conductivity can be further improved by adding conventionally used conductive material particles such as metal powder.

By the way, in the present invention, the resin liquid for forming the conductive resin layer 11 is prepared by dissolving the five-component compound in a solvent, adding an oxidizing agent dropwise to polymerize it, and then combining it with a separately prepared thermosetting resin prepolymer solution. It can also be obtained by uniformly mixing. Also in this resin liquid, since the hetero5-membered ring polymer solution is uniformly mixed with the resin prepolymer solution,
The resulting conductive resin layer 11 has uniform conductivity in which the five-membered heterocyclic polymer is uniformly dispersed in the matrix resin. However, in this method, the 5-membered heterocyclic polymer tends to grow into an excessively high molecular weight polymer and become insolubilized. It is more suitable to limit the molecular weight.

Further, as shown in FIG. 3, the conductive roll of the present invention includes a conductive resin layer 12a provided on the outer periphery of the metal shaft 10, and a semiconductive resin containing the above-mentioned five-membered complex ring polymer on the outer periphery. A laminated structure including the layer 11 may also be used.

Next, examples will be described together with comparative examples.

[Example 1] A conductive roll having the structure shown in Fig. 1 (metal shaft 10+
A conductive resin layer 11) containing a five-membered heterocyclic polymer was specifically produced, and its function as a developing roll was evaluated.

That is, first, 100 g of phenolic resin prepolymer (number average molecular weight 930, softening point 93°C) was mixed with methanol 5
00 ml? Dissolve and add 10 ml of pyrrole (0,144
mol) was added. Then, 100 ml of ferric chloride methanol solution with a concentration of 0.123 mol was prepared at O″C under a nitrogen gas atmosphere.
ml was slowly added dropwise under stirring to carry out a polymerization reaction for about 1 hour. Using this resin liquid, a dip liquid having the following composition was prepared and poured into a dip tank (see FIG. 2).

<Dip liquid composition> Resin liquid solid content 100 parts by weight Curing agent (hexamine) 13 Calcium hydroxide 2 Glass fiber 5 Clay 10 Zinc stearate 2 On the other hand, prepare a metal shaft with a shaft diameter of 8φ, After coating the resin liquid to a thickness of 500 μm and drying it at room temperature,
A conductive resin layer was formed by heating and curing at 00°C for 2 hours. In this way, the desired conductive roll was obtained.

[Example 2] A resin liquid was obtained in the same manner as in Example 1 above, and then heated to 70°C.
Methanol was removed from the residue and dried under vacuum at 70°C to obtain a black solid. Using this solid material, extrusion molding pellets having the following composition were made.

<Pellet composition> Resin solid 100 parts by weight Curing agent (hexamine) 13 Calcium hydroxide 2 Glass fiber 50 Clay 10 Zinc stearate 2 Then, using this pellet, extrusion molding was performed according to a conventional method, A resin sleeve with two wall thicknesses was obtained. and,
The intended conductive roll was obtained by fitting this sleeve onto the same metal shaft as above.

[Comparative example]

No 5-membered heterocyclic compound was added. A conductive roll was obtained in the same manner as in Example 2 except for the above. However, 30 parts of graphite was added when producing pellets for extrusion molding.

The distribution of volume resistivity in the axial direction of the thus obtained experimental and comparative products was investigated.

The results are shown in FIG.

As can be seen from this figure, all the products according to the implementation have the same resistivity, and the conductivity is uniform in the axial direction. On the other hand, the resistivity of the comparative products is uneven, and the difference between the two is obvious.

Further, each of the conductive rolls described above was used as a developing roll of an actual electrophotographic copying machine, and the image quality thereof was evaluated. The results are shown in the table below.

From the above results, 1. It was found that all copies made using the separate product were good.

[Effects of the Invention] As described above, the conductive roll of the present invention has a surface layer formed of a conductive resin layer in which a five-membered heterocyclic polymer is uniformly introduced into a resin matrix using a solvent. Because of this, it has excellent characteristics of uniform conductivity and high reproducibility. In addition, it is easy to keep the conductivity of the material within an appropriate range, and it is highly applicable. Therefore, when this conductive roll is used as a developer component of an electrophotographic copying machine, a copied image of excellent image quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating a method of forming a conductive resin layer of the present invention, and FIG. 3 is a diagram showing another embodiment of the present invention. 4 is an explanatory diagram for explaining the principle of copying, and FIG. 5 is a characteristic curve diagram showing the distribution state of volume resistivity in the axial direction of the conductive roll. 10... Metal shaft 11... Conductive resin layer Patent applicant Tokai Rubber Industries Co., Ltd. Agent Patent attorney Yukihiko Nishi Figure 3 Figure 5

Claims (1)

[Claims] (1) The surface layer is formed of a conductive resin layer made of a conductive resin composition mainly composed of a dispersion in which a five-membered heterocyclic polymer is uniformly dispersed in a thermosetting resin matrix. A roll characterized by: