JP3042061B2 - 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 generally includes (a) a roll formed of only metal;
(B) 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, It is difficult to control the semiconductivity (electrical resistance) to a constant value when forming the layer. When an insulating layer is formed, the charge generated by frictional charging is difficult to escape, and therefore the charge is excessively accumulated. Therefore, the toner is less likely to adhere to the developing roll and fly to the photosensitive drum 1. That is, there is a problem that charging of the toner or the like 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]

In order to achieve the above object, a conductive roll according to the present invention is a conductive roll having a conductive layer formed on an outer periphery of a shaft, wherein the conductive layer is formed of an organic material. The composition is such that it is formed of a conductive composition in which the following components (A) and (B) are dispersed and contained in a polymer binder resin. (A) Conductive powder. (B) A porous filler impregnated with a charge control agent.

[0007]

In other words, the present inventors have made a series of studies to improve the uniform chargeability and charge amount of a conductive layer formed on the outer peripheral surface of a conductive roll such as a developing roll. As a result, when a conductive layer is formed using a conductive composition in which a porous filler impregnated with a charge controlling agent is dispersed and contained in an organic polymer binder resin, uniform chargeability and a sufficient charge amount are obtained. We have found what we can achieve and arrived at this invention.

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.

The conductive layer formed along the outer periphery of the shaft body is made of a special porous filler in which a conductive powder (A component) and a charge controlling agent are impregnated in an organic polymer binder resin. It is formed using a conductive composition in which the agent (component B) is dispersed and contained, and its thickness is preferably set to 50 to 300 μm.

The organic polymer binder resin is not particularly limited and may be appropriately selected and used according to the purpose. Among them, a polyamide resin or the like is preferable.

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

The special porous filler (component B) used together with the conductive powder (component A) is obtained by impregnating the pores of the porous filler with a charge controlling agent. 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. These are used alone or in combination. The porous filler has a particle size of 20 to 200 μm.
And a porosity of 20 to 90% is preferably used.

As the charge control agent impregnated in the porous filler, an electron-donating dye such as a nigrosine dye, an alkoxylated amine, a quaternary ammonium salt, phosphorus and Tungsten alone and these compounds, molybdate chelate pigment,
Examples include fluorine-based activators, hydrophobic silica, and 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, and a copper phthalocyanine are used. Examples thereof include sulfonylamine, metal salts of naphthenic acid, metal salts of fatty acids, fatty acid soaps, and polymers having carboxyl groups and nitro groups.

The porous filler impregnated with the charge control agent can be prepared in the same manner as a general coupling treatment. For example, it can be prepared by adding a required amount of a charge control agent dissolved in a solvent (evaporable substance such as methanol, methyl ethyl ketone (MEK) or water) while stirring the porous filler at a high speed. At this time, it is necessary to add excessively in order to impregnate the inside of the porous filler.

The content ratio of the special porous filler (component B) impregnated with such a charge control agent is 5 to 100 parts by weight (hereinafter abbreviated as "parts") of the organic polymer binder resin. It is preferable to set in the range of 50 parts. That is, if the content ratio of the special porous filler is less than 5 parts, the sufficient effect of the charge control agent cannot be obtained, and if it exceeds 50 parts, the electric resistance of the resin composition in which the porous filler is blended becomes low. This is because there is a tendency that the height is increased and the charge is excessively increased.

In addition, a dispersant or the like is appropriately added to the conductive composition, if necessary, in addition to the above components.

The conductive roll of the present invention can be manufactured using the above-mentioned components, for example, as follows. That is, the organic polymer binder resin, conductive powder,
A porous filler impregnated with a charge controlling agent is blended, and this blend is mixed and stirred using a twin-screw extruder or the like to form a conductive composition. Then, the conductive composition is poured into a predetermined mold having a metal shaft (core bar), and cured to produce a conductive roll having a structure as shown in FIG. be able to. In the figure, 10 is a core metal, 11
Is a conductive layer.

Such conductive rolls include not only conductive rolls for electrophotographic copying machines but also facsimile,
Widely used for various conductive rolls such as printers.

[0021]

As described above, according to the conductive roll of the present invention, the conductive layer is made of an organic polymer binder resin in which the conductive powder (component A) and the charge control agent are impregnated with a porous material. Since it is formed of a special conductive composition in which the agent (component (B)) is dispersed and contained, it has a uniform chargeability and a sufficient charge amount.

Next, examples will be described together with comparative examples.

Prior to the examples, porous fillers A and B impregnated with two kinds of charge control agents were prepared according to the following method.

[Porous Filler A Impregnated with Charge Control Agent] While rotating sepiolite powder (Milcon LS) with a Hensiel mixer, aminosilane was made into a methanol solution, and 10% of the sepiolite powder was added.
After evaporating the methanol, the mixture was treated at 120 ° C. for 1 hour, and then loosened again with a Hensiel mixer to prepare a porous filler A impregnated with a charge controlling agent.

[Porous Filler B Impregnated with Charge Control Agent] 10% of an azo dye dissolved in toluene was added to sepiolite powder while rotating with a Hensiel mixer in the same manner as in the above-mentioned porous filler A. After evaporating the toluene, the mixture was loosened with a Hensiel mixer to prepare a porous filler B impregnated with a charge control agent.

[0026]

Examples 1 to 6 A charge controlling agent impregnated porous filler produced according to the above-mentioned production method and raw materials shown in the following Table 1 were blended in the ratio shown in the same table, and the conductive composition was kneaded by a twin screw extruder. I got something. Next, a conductive layer was formed on the outer periphery of the core by injecting the conductive composition into a mold having a core having a diameter of 20 mm. Thus, a conductive roll as shown in FIG. 1 was manufactured.

[0027]

[Table 1]

[0028]

Comparative Example 1 A porous filler impregnated with a charge control agent was not used. Otherwise in the same manner as in Example 1, a conductive roll was manufactured.

[0029]

Comparative Examples 2 and 3 Each component containing a charge controlling agent shown in Table 2 below was used in the proportion shown in the same table without using a porous filler.
Otherwise in the same manner as in Example 1, a conductive roll was manufactured.

[0030]

[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.

[0033]

[Table 3]

[0034]

[Table 4]

From the results shown in Tables 3 and 4, all of the products of the 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 configuration diagram illustrating a measurement state of a Faraday cage method for evaluating toner charging properties.

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

[Explanation of symbols]

 10 core metal 11 conductive layer

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Claims (1)

(57) [Claims] 1. A conductive roll having a conductive layer formed on the outer periphery of a shaft, wherein the conductive layer comprises the following components (A) and (B) in an organic polymer binder resin. A conductive roll formed of a conductive composition dispersed and contained. (A) Conductive powder. (B) A porous filler impregnated with a charge control agent.