JPH0535086A - Conductive roll - Google Patents

Abstract

PURPOSE:To obtain the conductive roll with which a sufficient electrostatic charge quantity is obtainable and which has a uniform electrical conductivity by forming a conductive layer of a conductive compsn. contg. a porous packing material and impregnating a charge control agent into the porous packing material. CONSTITUTION:The conductive layer 11 is formed on the outer periphery of an arbor 10 by using the conductive compsn. consisting of an org. high-polymer binder resin, the porous packing material and conductive powder and the charge control agent is impregnated into the porous packing material. Cellulose powder, wood meal, sepiolite, etc., are used as the porous packing material. The content of such porous packing material is preferably set in a 5 to 50 pts.wt. range per 100 pts.wt. org. high-polymer binder resin. The conductive powder is exemplified by metal oxide powder, etc., such as carbon black and the content ratio thereof is preferably in a 5 to 30vol.% range in the conductive compsn. The charge control agent to be impregnated into the porous packing material is selected from various kinds of polymers, etc., according to the electrostatic charging of toners to minus and plus.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, the copying method of an electrophotographic copying machine is
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 the image to be copied of the object to be copied, whereby an electrostatic latent image is formed on the outer peripheral surface. Form. Next, a developer (toner) is supplied from a toner supply device (not shown) onto the developing roll 2 that is provided opposite to the photosensitive drum 1, and the outer peripheral surface of the developing roll 2 and the layer forming blade 3 are connected to each other. The toner is triboelectrically charged by the frictional force between the toner and the electrostatic latent image on the photosensitive drum 1 to fly by electric attraction to form a toner image, which is transferred to the copy paper 5 and fixed. This is a method of copying by doing.
In the electrophotographic copying machine, the layer forming blade 3
In general, a rubber material is used, and the plate member 4 is used as a material for attaching it to the main body of the electrophotographic copying machine.

[0003]

In the developing roll 2 described above, (a) a roller formed of only metal, and (b)
There are two types, one in which the roll main body is made of metal and a layer made of a resin composition (or a rubber composition) or the like is formed on the outer circumference thereof. If the material of the developing roll 2 of (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 the charges charged on the surface escape. The problem arises. In addition, the main body of the developing roll 2 of (b) is made of metal such as aluminum or stainless steel, and a layer having various characteristics by using a resin composition (or a rubber composition) or the like on the outer periphery of the roll main body. Each of the rolls formed with has the following problems. If a conductive layer is formed, the charged charge escapes to the surface of the conductive layer and the chargeability of toner or the like is poor.If a semi-conductive layer is formed, the charging itself is advantageous. It is difficult to control the semi-conductivity (electrical resistance) to a constant value during layer formation. When an insulating layer is formed, it is difficult for the electric charge generated by frictional charging to escape, and therefore too much electric charge accumulates. , The toner adheres to the developing roll and the photosensitive drum 1
Difficult to fly to. That is, there is a problem that the charge of the toner cannot be constantly controlled.

Therefore, in order to solve the above problems, the chargeability is generally controlled by dispersing and containing a charge control agent in the resin composition (or rubber composition). However, the effect of controlling the charging property is not sufficient if the charge control agent is simply dispersed and contained as described above. For example, if the charge control agent is too widely dispersed, no effect will be obtained, and conversely, if the dispersibility is poor, there will be a problem of bleeding on the roll surface. For these reasons, proper dispersion control of the charge control agent is desired, but in reality, it is very difficult to control the dispersion of the charge control agent.

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

[0006]

In order to achieve the above object, the conductive roll of the present invention comprises a conductive composition comprising the following components (A) to (C) on the outer periphery of a shaft body. A conductive layer is formed and the component (B) is impregnated with a charge control agent. (A) Organic polymer binder resin. (B) Porous filler. (C) Conductive powder.

[0007]

That is, 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 was formed using a conductive composition in which a porous filler was dispersed and contained in an organic polymer-based binder resin, and when the conductive layer was impregnated with a charge control agent, the charge control agent was Permeated and impregnated into a porous filler,
It has been found that the charge control agent is uniformly dispersed in the conductive layer to obtain uniform chargeability and a sufficient charge amount, and the present invention has been reached.

Next, the present invention will be described in detail.

The conductive roll of the present invention comprises a shaft and a conductive layer formed around the shaft.

The shaft body is not particularly limited, and a metal core made of a solid metal body or a metal cylindrical body having a hollow hollow inside is used.

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. It is formed by impregnating a conductive layer formed by the above conductive composition with a charge control agent. The thickness is preferably set to 50 to 300 μm.

The organic polymer binder resin is not particularly limited and may be any conventionally known one. Among them, it is preferable to use a polyamide resin or the like.

Examples of the above-mentioned porous filler include cellulose powder, wood powder, sepiolite, silicon powder (oil absorbability), water-absorbing and oil-absorbing resins such as polyacrylate, starch, polyvinyl alcohol and polyethylene oxide. To be These may be 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 “part”). That is, when the content ratio of the porous filler is less than 5 parts, a sufficient effect of the charge control agent cannot be obtained, and conversely, when it exceeds 50 parts, the electrical resistance of the conductive composition containing the porous filler is high. This is because there are tendencies such as dullness and excessive charging.

Examples of the above-mentioned conductive powder include carbon black and metal oxide powder such as c-ZnO. The above "c-" means that it has 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 control agent impregnated in the conductive composition is an electron-donating dye such as a nigrosine dye, an alkoxylated amine, a quaternary ammonium salt, phosphorus and Examples include simple substances and compounds of tungsten, molybdic acid chelate pigments, fluorine-based activators, hydrophobic silica, polymers having basic groups such as amino groups. 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, an acid group excess polyester, or a copper phthalocyanine is used. Sulfonylamine, naphthenic acid metal salt,
Examples thereof include metal salts of fatty acids, resin acid soaps and polymers having a carboxyl group or a nitro group.

The conductive roll of the present invention can be manufactured using the above raw materials, for example, as follows. That is, first, the organic polymer binder resin, the porous filler, and the conductive powder are mixed, and this mixture 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 in which a metal shaft body is arranged and cured to form a conductive layer on the surface of the shaft body (core metal). Then, the charge control agent is dissolved in a solvent and applied to the surface of the conductive layer with a brush or the like, or the shaft body on which the conductive layer is formed is immersed in a solution containing the charge control agent to conduct electrical conductivity. The layer is impregnated with a charge control agent. And by removing the solvent,
A conductive roll having a structure as shown in FIG. 1 can be manufactured. In the figure, 10 is a core metal, and 11 is a conductive layer.

Solvents for dissolving the charge control agent include toluene, methanol, acetone, xylene, water,
Methyl ethyl ketone and the like are included, and the concentration thereof is 5 to 20.
It is preferable to set it to the weight percent. Furthermore, it is preferable that the charge control agent is used in an amount of 1 to 30 parts per 100 parts of the organic polymer binder resin.

The conductive roll thus obtained is
As shown in FIG. 2, the conductive layer 11 has a porous filler 13 dispersed in an organic polymer binder resin cured body 12 (conductive powder is omitted). The charge control agent 14 is impregnated in the porous filler 13. This is because the solution containing the charge control agent 14 permeates the organic polymer-based binder resin cured body 12 to impregnate the charge control agent 14 into the porous filler 13 or the porous filler 13 is connected to the porous filler 13. Charge control agent 1 through the connecting part
4 containing solution permeates and the charge control agent 1 is introduced into the porous filler 13.
4 is considered to be impregnated. Therefore, 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 it is widely used not only as such a conductive roll but also as various conductive rolls such as facsimiles and printers.

[0020]

As described above, in the conductive roll of the present invention, the conductive layer is formed by the conductive composition in which the organic polymer binder resin contains the porous filler dispersed therein.
This conductive layer is impregnated with a charge control agent. For this reason,
A 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 As raw materials for forming a conductive layer, the raw materials shown in Table 1 below were mixed in the proportions shown in the same table, and kneaded by a twin-screw extruder to obtain conductive compositions. Next, a conductive layer was formed by injecting the conductive composition into a mold having a cored bar with a diameter of 20 mm and curing it by heating. On the other hand, toluene was used for the nigrosine dye and monoazo dye as a solvent, and methanol was used for the aminosilane compound, and dissolved to prepare a charge control agent-containing solution having a concentration of 20% by weight. The target conductive roll having the structure shown in FIG. 1 was manufactured by polishing the surface of the resin conductive layer of the core metal on which the conductive layer was formed with paper or the like in this solution containing the charge control agent and then immersing it. The cellulose powder in Table 1 below has a particle size of 100 μm, and sepiolite has a fiber length of 50.
μm and fiber diameter 0.2 μm were used.

[0022]

[Table 1]

[0023]

[Comparative Examples 1 to 3] As the conductive layer forming material, the raw materials shown in Table 2 below were mixed in the proportions shown in the same table and kneaded with a twin-screw extruder to obtain a conductive composition. Next, a conductive layer was formed by injecting the conductive composition into a mold having a cored bar with a diameter of 20 mm and curing it by heating. On the other hand, toluene was used for the nigrosine dye and monoazo dye as a 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 on which the conductive layer was formed with paper or the like in the solution containing the charge control agent, and then immersing it.

[0024]

[Table 2]

The electrical resistance and charge index of each conductive roll thus obtained were measured and evaluated, and the results are shown in Tables 3 and 4 below. The charge amount index is
It was measured by the following method.

[Charge Amount Index] Under the condition of 25 ° C. × 55% RH, as shown in FIG. 4, a toner 32 layer is formed on the surface of the conductive roll 30, and the suction pump 33 sucks the toner 32 to suck the toner 32. 34 (Faraday cage method). In the figure, 35 is a filter, 36 is an insulator pipe, and 37 is an electrometer. Then, the charge amount of Comparative Example 1 product was set to 100, and the charge amount of each conductive roll was expressed as an index.

[0027]

[Table 3]

[0028]

[Table 4]

From the results shown in Tables 3 and 4, the electrical resistance values of all the example products were the same as before, and the amount of charge increased. On the other hand, the charge amount of both Comparative Example 1 and Comparative Example 2 is small. Further, the product of Comparative Example 3 has a large charge amount, but the electric resistance value is abnormally increased.

[Brief description of drawings]

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

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

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

FIG. 4 is a configuration diagram showing a measurement state of a Faraday cage method for evaluating toner chargeability.

[Explanation of symbols]

10 core metal 11 Conductive layer 12 Organic polymer binder resin cured product 13 Porous filler 14 Charge control agent

Claims (2)

[Claims] 1. A conductive layer is formed on the outer circumference of a shaft by a conductive composition comprising the following components (A) to (C):
A conductive roll obtained by impregnating the component (B) with a charge control agent. (A) Organic polymer binder resin. (B) Porous filler. (C) Conductive powder. 2. An organic polymer-based binder resin 1 in which the content ratio of the porous filler which is the component (B) is the component (A).
The conductive roll according to claim 1, which is set to 5 to 50 parts by weight with respect to 00 parts by weight.