JPH0638171B2 - Charging member for electrostatic image development - Google Patents

Description

TECHNICAL FIELD The present invention relates to a member for imparting a charge to a toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Conventional technology]

Conventionally, as electrophotography, various methods are described in U.S. Pat.No. 2,297,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, but in short, they are photoconductive insulator layers. An electrostatic latent image is formed by applying a uniform electrostatic charge on the surface and irradiating the insulator layer with a light image, and then the latent image is developed and visualized by fine powder called toner in the art, After transferring the powder image to paper, etc.,
Fixing is performed by heating, pressurizing, or solvent vapor.

As a developing method applied to these electrophotographic methods,
It is roughly classified into a dry development method and a wet development method. The former is further divided into a method using a two-component developer and a method using a one-component developer. The two-component developing method includes a magnet brush method using an iron powder carrier, a cascade method using a bead carrier, and a fur brush method using a fur, depending on the type of carrier that carries the toner.

Further, the one-component developing method includes a powder cloud method in which toner particles are sprayed, and a contact developing method in which toner particles are directly brought into contact with an electrostatic latent image surface for development (contact development or toner (Also referred to as development), a jumping development method in which toner particles are not directly contacted with the electrostatic latent image surface, but the toner particles are charged and fly toward the latent image surface by the electric field of the electrostatic latent image, magnetic conductivity. There is a magnetic dry method in which toner is brought into contact with the electrostatic latent image surface to develop the toner.

As a toner applied to these developing methods, a fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin is conventionally used.

For example, particles in which a colorant is dispersed in an adhesive resin such as polystyrene and finely pulverized to about 1 to 30 μm are used as a toner. A magnetic toner containing magnetic particles such as magnetite is used.

In the case of using a so-called two-component developer, the toner is usually mixed with carrier particles such as glass beads and iron powder before use.

Further, the toner has a positive or negative charge depending on the polarity of the electrostatic latent image to be developed.

To retain the electric charge in the toner, it is possible to utilize the triboelectric chargeability of the resin, which is a component of the toner, but in this method the toner chargeability is small, so the image obtained by development is easily fogged and is not clear. Becomes Therefore,
In order to impart a desired triboelectric charging property to a toner, a dye, a pigment, or a charge control agent that imparts the charging property is added.

[Problems to be solved by the invention]

However, these additives have to be exposed to the toner surface to some extent in order to impart chargeability. Therefore, these additives fall off from the toner surface due to friction between toners, collision with a carrier, friction with an electrostatic latent image holding member, contamination of the carrier, electrostatic latent image holding member such as a photoconductor belt. Alternatively, contamination of the drum etc. occurs. As a result, the charging property deteriorates, the deterioration progresses as the number of durable sheets increases, the image density decreases, and fine line reproducibility and fog properties become practical problems.

This can be improved by improving the affinity and dispersibility of the toner binder and the dye, pigment or charge control agent that imparts the charging property, but if the surface treatment is performed to increase the affinity of these additives. In many cases, the charge imparting property decreases, and when the mechanical shear is applied strongly and finely dispersed, the proportion of the additive that appears on the toner surface decreases,
There is a tendency that the chargeability is not sufficiently imparted. For these reasons, the charge imparting additives that are sufficiently satisfactory in practice are extremely limited, and only a few have been put into practical use. In particular, in order to cope with an increase in demand for not only black and white images but also color images in the future, it is preferable that the additive to be added to the toner is colorless, and at present, there are few practical additives that meet this condition.

[Means for solving problems]

In view of the above-mentioned circumstances, the present inventors have made earnest studies to carry out charging by means of carrier regulation such as carriers, sleeves, doctor blades, or charging members, without taking the means of carrying out addition of toner.

The charge imparting member is a member capable of being in contact with the toner and imparting an electric charge necessary for development, or an auxiliary charge. In this method, the toner does not need to contain a charge-imparting additive, and therefore the above-mentioned problems such as contamination of the carrier and the photoconductor do not occur, the chargeability is lowered during image formation, and the latent image is not formed. Do not disturb. Further, the color toner can be easily charged.

However, in order to regulate the transportation of carriers, sleeves, doctor blades, etc., or to make the charging member possess the charge imparting property, a material having a strong charge imparting ability and capable of being applied, coated or dispersed on the member must be used.
Further, the carrier is often used without replacement for a long period of time, and the sleeve is often used until the main body of the developing machine becomes unusable. Therefore, the charging member must be durable for a long period of time.

An object of the present invention is to provide a charging member that solves the above-mentioned problems.

A further object of the present invention is to provide a charging member that imparts a proper negative charging property to the toner.

A further object of the present invention is to provide a charge imparting member that is less likely to deteriorate in performance after long-term use.

A further object of the present invention is to provide a charging member that can obtain an image with excellent fine line reproducibility and gradation.

A further object of the present invention is to provide a charging member suitable for colorization.

That is, the present invention is a charge imparting member for imparting a negative triboelectric charge, which has a phosphine compound represented by the following formula (I) on at least the surface thereof. It is in.

(However, R ₁ , R ₂ , and R ₃ represent a substituent having a hydrocarbon as a basic skeleton such as an alkyl group, a cyclic alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aralkyl group, and an acyl group.) R ₁ To R ₃ are usually the above groups having 1 to 20 carbon atoms and may be the same or different from each other. Cyclic alkyl group,
The aryl group and aralkyl group may be a single ring or a single ring aggregate. It may be a ring structure having an electron donating group substituent such as an amino group.

The following are typical specific examples of the compound used in the charging member of the present invention.

[Compound example]

(1) (2) (3) (Four) (Five) (6) (7) (8) (9) (Ten) These compounds are synthesized by known methods. Compound
(1) is created as follows.

P-tert-butyl-phenoxysodium [synthesized by reacting metallic sodium with p-tert-butylphenol (Tokyo Chemical Industry Co., Ltd.)] on phosphorus trichloride (Kishida Chemical Co., Ltd.) to form phosphorous acid Tris (p-tert-butylbenzene) is obtained. Next, phenylmagnesium bromide was allowed to act on the above substance in ether, and tris (p-tert-butylbenzene) phosphine was obtained by the substitution reaction.

The compound may be used as it is as a charge-imparting material by being dispersed in a solvent or a dispersion medium as it is, or may be used by being dispersed in a resin.

A ceramic powder such as silica powder, aluminum oxide, cerium oxide, or silicon carbide may be used as a filler. Further, a conductivity-imparting agent such as carbon black or tin oxide may be used for adjusting the conductivity. Further, a releasing agent or the like, for example, a fatty acid metal salt, vinylidene fluoride, or the like may be mixed and used in order to prevent accumulation of the spent toner on the sleeve or the carrier surface.

Moreover, as the resin for dispersion, a general resin can be used. For example, polystyrene, polyacrylic acid ester, polymethacrylic acid ester, polyacrylonitrile, rubber resin such as isoprene and butadiene, polyester, polyurethane, polyamide, epoxy resin, rosin, polycarbonate, phenol resin, chlorinated paraffin, polyethylene, polypropylene, Silicone resin, Teflon and their derivatives, copolymers,
Mixtures can be used.

When the charge-imparting compound is mixed and attached to a carrier, the weight is 1 g to 100 g, preferably 5 g per 1 kg of the carrier.
g~20g good adhesion amount when attaching the like sleeve, the effective surface area of 1 cm ² per 0.01Mg～10mg, preferably
0.1mg-2mg is good. If it is less than the above range, the charge imparting power and life are insufficient, and even if it is used beyond the above range, the effects such as charge imparting power and life are saturated and useless.

The carrier to which the compound can be applied is not particularly limited, but examples thereof include powders or particles of metals such as iron, nickel, aluminum, and copper and alloys thereof, powders or particles of metal compounds including metal oxides, glass, SiC. ， BaTi
O _3, ceramic powder or particles, such as SrTiO _3, the surface of the powder or particulate those treated with resin or the like, can be cited resin powder, resin powder containing a magnetic material, and the like.

Further, the sleeve to which the compound can be applied can be generally used as a sleeve such as metal materials such as metals such as iron, aluminum, stainless steel, nickel or alloys containing these, and non-metal materials such as ceramics and plastics. Any material may be used.

Further, the toner used when using the member of the present invention is effective for both non-magnetic and magnetic toners, and is applicable to all systems in which toner is charged and developed regardless of the two-component developing method or the one-component developing method. Applicable.

For example, magnetic brush developing method, cascade developing method, fur brush developing method, so-called microtoning developing method using magnetic substance-containing resin powder as a carrier, or developing method using resin powder as a carrier, so-called jumping developing method, or non-magnetic toner It can be applied to a jumping development method for developing.

These toners may contain a small amount of a charge-imparting substance, for example, a dye, a pigment, or a so-called charge control agent, in order to more efficiently provide the charge, as long as it does not adversely affect the practice of the present invention. A fluidizing agent such as colloidal silica, an abrasive such as cerium oxide, strontium titanate, and silicon carbide, a metal stearate, and a lubricant such as polyvinylidene fluoride may be contained. Further, a conductivity imparting agent such as carbon black or tin oxide may be contained.

In order to manufacture the member of the present invention, it is advisable to hold the above compound on the surface of a material or equipment that has a chance to make sufficient contact with the toner before development, specifically, the surface of a carrier, a sleeve, a doctor blade or the like. That is, in the carrier treatment, a usual method such as immersing a solution in which the above compound is dissolved or dispersed in a tank and adhering it to the carrier core surface by using a spray or a fluidized bed is adopted.

When the sleeve is coated, the same solution is used, and a method such as a dipping method, a spray method, or a brush coating method can be used.

Further, the member of the present invention can be manufactured by incorporating the above compound into a moldable resin by a known method and then molding the carrier, sleeve, doctor blade and the like.

〔Example〕

Example 1 100 g of the compound (1) was dissolved and dispersed in methyl ethyl ketone 1 and 1 kg of an iron powder carrier (particle size: 250 to 400 mesh)
Were dispersed and mixed by stirring in a ball mill for about 30 minutes. After drying this iron powder carrier mixture and completely removing the solvent,
After lightly agglomerating, an electrostatic charge developing member of the present invention was obtained.

Separately, a toner was prepared according to the following formulation by a conventional material and method. The charge-imparting substance was not included (the following parts indicate parts by weight).

Polystyrene (Brand name D-125: Shell Chemical Co., Ltd.) 100 parts Carbon Black (Brand name Raven 3500: Cabot Company) 6
Parts The above toner materials are kneaded, crushed, and classified to have a particle size of 1 to
Aligned to 30 μm. This toner and the carrier were mixed at a weight ratio of 10: 100 to obtain a developer. When the tribo of this developer was measured by the blow-off method, it was -9.4 μc / g. Using this developer, an image was printed on a Canon NP-5000 copier, and it showed good fine line reproducibility, good gradation, and no fog even in the durability test of 50,000 sheets.

Example 2 100 g of polymethylmethacrylate resin in xylene 1
Was dissolved, and 50 g of Compound Example (2) was mixed therein. This was treated into an iron powder carrier of 1 kg in the same manner as in Example 1 to obtain a carrier having a charge imparting effect which is a member of the present invention.

Separately, a toner exactly the same as in Example 1 was prepared, and the toner and the carrier were mixed in the same weight ratio as in Example 1 to obtain a developer.

When the tribo of this developer was measured by the blow-off method, it was -8.7 μc / g. Using this developer, an image was printed on a Canon NP-5000 copier, and it showed good fine line reproducibility and gradation even at the endurance test of 50,000 sheets, and no fog was observed. .

Example 3 100 g of polymethylmethacrylate resin in xylene 1
Was dissolved and 50 g of the compound example (3) was mixed to prepare a solution. Dipping the developing sleeve for Canon NP-400RE (stainless steel) to the solution, as the amount of deposition of compound examples on the surface of the sleeve (3) is 0.1mg / cm ² ~0.6mg / cm ² of the coated invention The member was obtained. This sleeve was set in the original developing machine.

The toner was made to have a particle size of 1 μm to 30 μm according to the following formulation through general kneading, pulverizing, classifying and the like.

Poly (styrene-butyl methacrylate) w = 300,000 100 parts Release agent (trade name PE-130: manufactured by Hoechst) 4 parts Magnetic powder (trade name BL-200: manufactured by Titanium Industry Co., Ltd.) 60 parts Using this toner, Canon Images were produced and a durability test was performed using a NP-400RE manufactured by the company. At 50,000 sheets, there was no change in the image from the beginning, good fine line reproducibility and gradation, and no fogging.

Further, when the surface potential of the toner on the sleeve was measured after the end of the durability test, it was −32 V, and it was confirmed that the toner was completely negatively charged.

Example 4 80 g of a polycarbonate resin was dissolved in xylene 1,
Further, a solution was prepared by mixing 20 g of the compound example (4). Dip the developing sleeve (made of aluminum) of the developing machine of the blue cartridge for PC-20 made by Canon to this solution,
The amount of Compound Example (4) deposited on the sleeve surface is 0.1 mg / cm ^{2 to} 0.
The material of the present invention was obtained by coating as much as 5 mg / cm ² .

This sleeve was set in the original developing machine.

On the other hand, the toner is prepared by the following formulation, and the particle size is 1μ to 30μ.
I prepared it.

Poly (styrene-butylmethacrylate) w = 150,000 100 parts Release agent (trade name PE-130: manufactured by Hoechst) 4 parts Blue colorant (phthalocyanine pigment) 6 parts Using this toner, a developing machine equipped with the above sleeve is used. A modified PC-20 was used to enable reversal development, and a durable image was printed.

190 g of toner was charged, and the test was conducted until the toner ran out. However, there was no change in the image, and a clear blue image with good fine line reproducibility and gradation was obtained. Further, the surface potential of the toner on the sleeve was measured and found to be -21V, confirming the charging effect.

Examples 5-8 The experiment was repeated exactly as in Example 1 except that the compound was replaced.

[Advantages of the Invention] By using the charging member according to the present invention, an image obtained by developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, etc. has very little change over a long period of time, and fine line reproducibility and level. Good tonality and less fogging. Further, it can be effectively used for color development, and an extremely clear image can be obtained.

Front page continuation (72) Takeshi Ikeda Inventor Takeshi Ikeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-59-124347 (JP, A) "Coloring Material" Volume 50 9 (1977) 517-519, 522

Claims (2)

[Claims] 1. A charge imparting member for imparting a negative triboelectric charge to a toner, which has a phosphine compound represented by the following general formula on at least the surface thereof. . (However, R ₁ , R ₂ and R ₃ are an alkyl group, a cyclic alkyl group,
Alkenyl group, aryl group, acyl group, aralkyl group,
A substituent having a hydrocarbon of an alkoxy group as a basic skeleton is shown. ) 2. A charge imparting member for developing an electrostatic charge image according to claim 1, wherein the compound according to claim 1 is coated on a carrier, a sleeve or a doctor blade.