JP3042060B2 - Conductive roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine, a facsimile, a developing roll of a printer, a charging roll,
The present invention relates to a conductive roll used for a transfer roll and the like.

[0002]

2. Description of the Related Art In general, the copying method of an electrophotographic copying machine is as follows.
As shown in FIG. 3, the outer peripheral surface of the photosensitive drum 1 is uniformly charged, and then the outer peripheral surface is exposed through a copy image of the copy body, thereby forming an electrostatic latent image on the outer peripheral surface. Form. Next, a developer (toner) is supplied from a toner supply device (not shown) onto the developing roll 2 opposed to the photosensitive drum 1, and the outer peripheral surface of the developing roll 2 and the layer forming blade 3 are formed. The toner is frictionally charged by the frictional force between the two, and the toner is caused to fly by an electric attraction to the electrostatic latent image on the photosensitive drum 1 to form a toner image, which is transferred to the copy paper 5 and fixed. This is a method of making a copy.
In the above electrophotographic copying machine, the layer forming blade 3
In general, a rubber material is used, and a plate material 4 is used as a material for attaching the rubber material to a main body of an electrophotographic copying machine.

[0003]

The developing roll 2 includes (a) a roll formed only of a metal and (b) a roll formed of only a metal.
Two types of roll main bodies are made of metal, and a layer made of a resin composition (or rubber composition) is formed on the outer periphery of the roll main body. If the material of the developing roll 2 in (a) above is made of metal, the surface roughness of the roll cannot be kept constant due to friction with the layer forming blade 3 and the like, and charges charged on the surface escape. Problems arise. Further, the main body of the developing roll 2 of (b) is made of a metal such as aluminum or stainless steel, and a layer having various characteristics using a resin composition (or a rubber composition) or the like around the roll main body. Each of the rolls formed with has the following problems. When the conductive layer is formed, the charge on the surface of the conductive layer escapes, and the chargeability of the toner or the like is poor. When the semiconductive layer is formed, the charge itself is advantageous, but the semiconductive layer is advantageous. It is difficult to control the semiconductivity (electric resistance) to a constant value when forming the layer. If an insulating layer is formed, it is difficult for the charge generated by the triboelectric charge to escape, and therefore the charge is excessively accumulated. The toner adheres to the developing roll and the photosensitive drum 1
Difficult to fly. That is, there is a problem that the charge of the toner cannot be controlled to be constant.

[0004] Therefore, in order to solve the above-mentioned problems, the chargeability is generally controlled by dispersing a charge control agent in the resin composition (or rubber composition). However, simply adding a charge control agent in a dispersed manner as described above is not sufficient in controlling the chargeability. For example, if the charge control agent is too widely dispersed, no effect can be obtained at all, and if the charge control agent is poorly dispersible, on the other hand, there is a problem that the charge control agent oozes out on the roll surface. For this reason, it is desired to appropriately control the dispersion of the charge control agent. However, it is actually difficult to control the dispersion of the charge control agent in practice.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a conductive roll capable of obtaining a sufficient charge amount and having a uniform chargeability.

[0006]

Means for Solving the Problems In order to achieve the above object, a conductive roll according to the present invention is provided on the outer periphery of a shaft by a conductive composition comprising the following components (A) to (C). The conductive layer is formed, and the component (B) is impregnated with a charge controlling agent. (A) Organic polymer binder resin. (B) a porous filler. (C) conductive powder.

[0007]

In other words, the present inventors have conducted a series of studies to improve the uniform chargeability and charge amount of the conductive layer formed on the outer peripheral surface of a conductive roll such as a developing roll. As a result, a conductive layer is formed using a conductive composition in which a porous filler is dispersed and contained in an organic polymer-based binder resin, and when the conductive layer is impregnated with a charge control agent, the charge control agent has Impregnated into porous filler,
The present inventors have found that the charge control agent is uniformly dispersed in the conductive layer, and that uniform chargeability and a sufficient charge amount can be obtained.

Next, the present invention will be described in detail.

[0009] The conductive roll of the present invention comprises a shaft and a conductive layer formed on the outer periphery thereof.

The shaft is not particularly limited, and a metal core made of a solid metal or a metal cylinder hollowed out inside is used.

[0011] The conductive layer formed along the outer periphery of the shaft is made of a conductive composition in which a porous filler and a conductive powder are dispersed and contained in an organic polymer binder resin. Formed, and then formed by impregnating a conductive layer formed from the conductive composition with a charge controlling agent. The thickness is preferably set to 50 to 300 μm.

The organic polymer-based binder resin is not particularly limited, and includes conventionally known ones. Among them, it is preferable to use a polyamide resin or the like.

Examples of the porous filler include water-absorbing and oil-absorbing resins such as cellulose powder, wood flour, sepiolite, silicon powder (oil-absorbing), polyacrylate, starch, polyvinyl alcohol and polyethylene oxide. Can be These are used alone or in combination. The porous filler preferably has a particle size in the range of 20 to 200 μm and a porosity of 20 to 90%. The content ratio of such a porous filler is preferably set in the range of 5 to 50 parts with respect to 100 parts by weight of the organic polymer binder resin (hereinafter abbreviated as “parts”). That is, if the content of the porous filler is less than 5 parts, the effect of the charge control agent cannot be sufficiently obtained. If the content exceeds 50 parts, the electric resistance of the conductive composition containing the porous filler is high. This is because there is a tendency such as dampness or excessive charging.

Examples of the conductive powder include carbon black and metal oxide powder such as c-ZnO. Here, “c−” means having conductivity.
And the content ratio of the conductive powder is 5 to 5 in the conductive composition.
It is preferably set in the range of 30% by volume.

The charge controlling agent impregnated in the conductive composition may be an electron-donating dye such as a nigrosine dye, an alkoxylated amine, a quaternary ammonium salt, phosphorus, or the like when the toner is negatively charged. Tungsten alone and compounds, molybdate chelate pigments, fluorine-based activators, hydrophobic silica, polymers having a basic group such as an amino group, and the like. When the toner is positively charged, an electron-accepting dye such as a metal complex salt of a monoazo dye, an organic complex of an electron acceptor, a chlorinated polyolefin, a chlorinated polyester, a polyester having an excessive acid group, and a copper phthalocyanine are used. Sulfonylamine, metal salt of naphthenic acid,
Examples include metal salts of fatty acids, resin acid soaps, and polymers having carboxyl groups and nitro groups.

The conductive roll of the present invention can be manufactured using the above-mentioned raw materials, for example, as follows. That is, first, the organic polymer-based binder resin, the porous filler, and the conductive powder are blended, and the blend is mixed and stirred using a twin-screw extruder or the like to prepare a conductive composition. This conductive composition is poured into a molding die provided with a metal shaft, and is cured to form a conductive layer on the surface of the shaft (core metal). Then, the charge control agent is dissolved in a solvent, and the solution is applied to the surface of the conductive layer with a brush or the like, or the shaft on which the conductive layer is formed is immersed in a charge control agent-containing solution. The layer is impregnated with a charge control agent. Then, by removing the solvent,
A conductive roll having a structure as shown in FIG. 1 can be manufactured. In the figure, reference numeral 10 denotes a metal core, and 11 denotes a conductive layer.

Solvents for dissolving the charge control agent include toluene, methanol, acetone, xylene, water,
Methyl ethyl ketone and the like, and the concentration is 5 to 20.
It is preferable to set the weight%. Further, the use ratio of the charge control agent is preferably set to 1 to 30 parts with respect to 100 parts of the organic polymer binder resin.

The conductive roll thus obtained is
In the conductive layer 11, as shown in FIG. 2, a porous filler 13 is dispersed in a cured organic polymer binder resin 12 (conductive powder is omitted). Then, the charge control agent 14 is impregnated in the porous filler 13. This is because the charge control agent 14 containing solution penetrates into the cured organic polymer binder resin 12 to impregnate the charge control agent 14 into the porous filler 13, or is connected to the porous filler 13. Charge control agent 1 through connection
4 containing solution permeates and charge control agent 1 in porous filler 13
4 would be impregnated. Accordingly, the charge control agent 14 is uniformly dispersed and controlled in the conductive layer 11.

The conductive roll of the present invention is most suitable as a conductive roll for an electrophotographic copying machine, but is widely used not only as such a conductive roll but also as various conductive rolls such as a facsimile and a printer.

[0020]

As described above, in the conductive roll of the present invention, the conductive layer is formed by the conductive composition in which the porous filler is contained and dispersed in the organic polymer binder resin.
This conductive layer is impregnated with a charge control agent. For this reason,
The charge control agent is impregnated in the porous filler. Therefore, it has a uniform chargeability and a sufficient charge amount.

[0021]

Examples 1 to 6 Raw materials shown in Table 1 below were blended in the proportions shown in Table 1 as materials for forming a conductive layer, and kneading was performed by a twin-screw extruder to obtain a conductive composition. Next, the conductive composition was poured into a mold having a cored bar having a diameter of 20 mm, and heated and cured to form a conductive layer. On the other hand, toluene was used for the nigrosine dye and the monoazo dye as the solvent, and methanol was used for the aminosilane compound, and dissolved to prepare a solution containing a charge controlling agent having a concentration of 20% by weight. The target conductive roll having the structure shown in FIG. 1 was produced by polishing the surface of the resin conductive layer of the core metal having the conductive layer formed thereon with paper or the like in this solution containing the charge control agent, and then immersing it. In addition, the cellulose powder in Table 1 below has a particle size of 100 μm, and sepiolite has a fiber length of 50.
μm and a fiber diameter of 0.2 μm were used.

[0022]

[Table 1]

[0023]

Comparative Examples 1 to 3 Raw materials shown in Table 2 below were blended in the proportions shown in Table 2 as materials for forming a conductive layer, and kneaded with a twin-screw extruder to obtain a conductive composition. Next, the conductive composition was poured into a mold having a cored bar having a diameter of 20 mm, and heated and cured to form a conductive layer. On the other hand, toluene was used for the nigrosine dye and the monoazo dye as the solvent, and methanol was used for the aminosilane compound, and dissolved to prepare a charge control agent-containing solution. A conductive roll was manufactured by polishing the surface of the resin conductive layer of the core metal having the conductive layer formed thereon with paper or the like in the solution containing the charge control agent and then immersing the surface.

[0024]

[Table 2]

With respect to each of the conductive rolls thus obtained, the electric resistance and the charge index were measured and evaluated, and the results are shown in Tables 3 and 4 below. Note that the charge amount index is:
It was measured by the following method.

[Charge Amount Index] Under the condition of 25 ° C. × 55% RH, a toner 32 layer is formed on the surface of the conductive roll 30 as shown in FIG. 34 (Faraday cage method). In the figure, 35 is a filter, 36 is an insulator pipe, and 37 is an electrometer. The charge amount of each conductive roll was expressed as an index with the charge amount of Comparative Example 1 as 100.

[0027]

[Table 3]

[0028]

[Table 4]

From the results of Tables 3 and 4, it can be seen that all of the products of Examples have an increased electric charge while maintaining the conventional electric resistance value. On the other hand, both the comparative example 1 and the comparative example 2 have a small charge amount. Further, the product of Comparative Example 3 has a large charge amount, but the electric resistance value is abnormally increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a conductive roll of the present invention.

FIG. 2 is a schematic diagram of a cross section of a conductive layer of the conductive roll of the present invention.

FIG. 3 is a main part configuration diagram of an electrophotographic copying machine in which a conductive roll is incorporated.

FIG. 4 is a configuration diagram illustrating a measurement state of a Faraday cage method for evaluating toner charging properties.

[Explanation of symbols]

 Reference Signs List 10 core metal 11 conductive layer 12 cured organic polymer binder resin 13 porous filler 14 charge control agent

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Claims (2)

(57) [Claims] 1. A conductive layer is formed on the outer periphery of a shaft body by a conductive composition comprising the following components (A) to (C):
(B) A conductive roll, wherein the component is impregnated with a charge control agent. (A) Organic polymer binder resin. (B) a porous filler. (C) conductive powder. 2. The content of the porous filler (B) is higher than that of the organic polymer binder resin 1 (A).
The conductive roll according to claim 1, wherein the amount is set to 5 to 50 parts by weight with respect to 00 parts by weight.