JPS61120168A - Element of supplying charge for electrostatic charge image development - Google Patents

Abstract

PURPOSE:To prevent a deterioration of a performance of the title element for a long period by coating a carrier and a sleeve for supplying the charge to the toner with a specific bismuthine compd., thereby supplying a negative charge to the toner. CONSTITUTION:A surface of the title element is coated with the compd. shown by formula I wherein Ar is an aryl group or its derivative, and is preferably coated with a compd. shown by formula II. By coating the title element with said compds., the above describec characteristics of the element is obtd. The toner is charged by the title element contg. the prescribed compd. and then developed, thereby obtaining an image having less a change of an image concentration and a good reproducibility of a fine line and also a good gradient and less tendency for a fog.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a member that charges toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Prior Art] As a conventional electrophotographic method, US Pat. No. 2,297,81
No. 11, Special Publication No. 42-23910 and Special Publication No. 43
Various methods are described in Japanese Patent No. 24748, etc., but in short, these methods apply a uniform electrostatic charge to a photoconductive insulating layer and irradiate the insulating layer with a light image to remove the electrostatic charge. An image is formed, the latent image is developed and visualized using fine powder called toner in the art, and if necessary, the powder image is transferred to paper or the like, followed by heating and pressing.1. Alternatively, fixing is performed using solvent vapor or the like.

The developing methods applicable to these electrophotographic methods are:
Broadly speaking, there are dry development methods and wet development methods. The former method is further divided into a method using a two-component developer and a method using a -component developer.

Two-component developing methods include a magnetic brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, etc., depending on the type of carrier that transports the toner.

In addition, the -component type development methods include the powder cloud method, in which toner particles are sprayed, and the contact development method, in which toner particles are brought into direct contact with the electrostatic latent image surface for development. (also referred to as toner development), jumping development method in which toner particles are not brought into direct contact with the electrostatic latent image surface, but are charged and flown toward the latent image surface by the electric field of the electrostatic latent image; There is the MagneDry method, which develops by bringing a conductive toner into contact with the electrostatic latent image surface.

As toners applied to these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used.

For example, particles obtained by dispersing a coloring agent in an adhesive resin such as polyethylene and pulverizing the particles into particles with about 1 to 30 corners are used as toner. As the magnetic toner, one containing magnetic particles such as magnetite is used.

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

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

In order to make the toner retain an electric charge, it is also possible to use the triboelectricity of the resin that is a component of the toner, but with this method, the toner's chargeability is small, so the images obtained by development are likely to fog and become unclear. becomes. Therefore,
In order to impart desired triboelectric charging properties to the toner, dyes, pigments, and even charge control agents that impart electrostatic properties are added to the toner.

[Problems to be Solved by the Invention] However, these additives must be present on the toner surface to some extent in order to impart charging properties, and as a result, friction between the toners, collision with the carrier, and electrostatic latent These additives fall off from the toner surface due to friction with the image carrier, resulting in contamination of the carrier, etc., and contamination of the electrostatic latent image carrier, such as the photoreceptor belt or drum. As a result, the charging property deteriorates, and as the number of durable sheets increases, the deterioration progresses, the image density decreases, and fine line reproducibility, fogging, etc. 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 chargeability, but if surface treatment is performed to increase the affinity of these additives, In many cases, the charge imparting properties are reduced, and if mechanical shear is strongly applied and finely dispersed, the proportion of additives that appear on the toner surface decreases.
There is a tendency that sufficient chargeability is not imparted. For these reasons, the number of charge-imparting additives that are sufficiently satisfactory for practical use is extremely limited, and only a small number of them have been put into practical use, especially in order to cope with the increasing demand for not only black and white images but also color images in the future. For this reason, it is preferable that the additive added to the toner be colorless, and there are currently almost no additives that have been put to practical use that meet this requirement.

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present inventors did not adopt a method of applying a charge using toner additives, but instead used means for controlling transport of the carrier, sleeve, doctor blade, etc., or using charging members. We conducted intensive studies to determine whether this would be possible.

The charge imparting member is a member that comes into contact with the toner and imparts a charge necessary for development, or is capable of imparting an auxiliary charge. In this method, there is almost no need to include charge-imparting additives in the toner, so the problems mentioned above, such as contamination of the carrier, photoreceptor, etc., do not occur, and chargeability decreases during image printing. , does not disturb the latent image, and can easily charge color toner.

Therefore, in order to control the conveyance of carriers, sleeves, doctor blades, etc., or to make charging members have chargeability, it is necessary to use materials that have strong chargeability and can be applied, coated, and dispersed on the member. Furthermore, since the carrier does not need to be replaced for a long period of time and the sleeve is often used until the main body of the developing machine becomes unusable, the charge imparting member must be able to withstand long-term use.

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

A further object of the present invention is to provide a charge imparting member that imparts appropriate negative chargeability to toner.

A further object of the present invention is to provide a charge-imparting member that does not deteriorate in performance even after long-term use.

A further object of the present invention is to provide a charge-imparting member capable of producing images with excellent fine line reproducibility and gradation.

A further object of the present invention is to provide a charge imparting member suitable for coloring.

That is, the present invention resides in a charge-imparting member for developing an electrostatic image, which is characterized by having a bismuthin compound represented by the following formula on its surface.

Ar -Br -Ar Ar (However, Ar represents an aryl group or a derivative thereof) The aryl group is usually a monocyclic ring, a fused ring, or a monocyclic aggregate,
In addition, its derivatives usually have CI ''' Co on the above aryl group.
An alkyl group consisting of o, a halogen group, a NO2 group, an alkoxy group, and an acyl group each having 1 to 5 partial substitutions are used.

Typical specific examples of bismuthine compounds used in the charge-imparting member of the present invention include the following.

[Compound example] These compounds are synthesized by known methods.

That is, it is synthesized by a reaction between an aromatic Grignard reagent and a bismuth halide.

[EL Application] The above compound may be used 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.

In addition, ceramic powder such as silica powder, aluminum oxide, cerium oxide, and silicon carbide may be used as a filler, and conductivity imparting agents such as carbon black and tin oxide may be used to adjust conductivity. Further, in order to prevent the accumulation of spent toner on the sleeve or carrier surface, a release agent such as a fatty acid metal group, vinylidene fluoride, etc. may be mixed and used.

Further, as the resin for dispersion, common resins can be used. For example, rubber resins such as polystyrene, polyacrylic ester, polyacrylic ester, polyacrylonitrile, isoprene, and butadiene, polyester, polyurethane, polyamide, Epoxy resins, rosins, polycarbonates, phenolic resins, chlorinated paraffins, polyethylene, polypropylene, silicone resins, Teflon and derivatives, copolymers and mixtures thereof can be used.

Furthermore, the sleeve to which the above compound can be applied is made of materials that can generally be used as sleeves, such as metals such as iron, aluminum, stainless steel, and nickel, or alloys containing these metals, and non-metallic materials such as ceramics and plastics. It is fine as long as it was there.

Furthermore, the toner used when using the member of the present invention can be either non-magnetic or magnetic toner, and is suitable for all methods of developing by charging the toner, regardless of whether it is a two-component development method or a -component development method. Applicable.

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

When the charge-imparting compound is mixed and deposited on a carrier, the amount of adhesion is 1 g to 100 g, preferably 5 g to 20 g, per IKg of carrier, and when it is applied to a sleeve, etc., the amount of adhesion is G-01 m per effective surface area IC12.
g~1111 mg, preferably 0.1a+g~2 mg
If it is less than the above am, the charge imparting power and lifespan will not be sufficient, and even if it is used beyond the above range, the benefits such as charge imparting power and life will be saturated and it will be useless.

The carrier to which the above compound can be applied is not particularly limited, but includes, for example, powders or particles of metals such as iron, nickel, aluminum, copper, and alloys thereof, powders or particles of metal compounds containing metal oxides, glass, To Si,
Examples include ceramic powders or particles such as BaTiO2 and 5rTi03, the surfaces of the above powders or particles treated with resin, resin powders, and resin powders containing magnetic materials.

These toners provide more efficient charging, so
Small amounts of charge-imparting substances such as dyes, pigments, or so-called charge control agents may be included as long as they do not adversely affect the practice of the invention, and fluidizing agents such as colloidal silica, cerium oxide, strontium titanate, etc. , an abrasive such as silicon carbide, a detergent such as a metal salt of stearate, or vinylidene fluoride, and a conductivity imparting agent such as carbon black or tin oxide.

In order to manufacture the member of the present invention, it is preferable to hold the compound on the surface of a material or equipment that has a sufficient opportunity to come into contact with the toner before the development stage, specifically, a carrier, a sleeve, a doctor blade, etc. That is, in the carrier treatment, a conventional method is employed, such as dipping a solution in which the above-mentioned compound is dissolved or dispersed in a tank, or applying the solution to the surface of the carrier core using a spray or a fluidized bed.

Further, when coating a sleeve or the like, a similar method such as using a solution, dipping, spraying, or brushing can be used.

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

[Example] Example 1 100g of compound example (1) in 1n of methyl ethyl ketone
Dissolve and disperse, and add iron powder carrier (particle size: 250 to 40
0mesh) Disperse IKg and mill in a ball mill for about 30
The mixture was stirred and mixed for several minutes. After drying this iron powder carrier mixture to completely remove the solvent, the agglomeration was slightly loosened to obtain an electrostatic charge developing member of the present invention.

Separately, toners were prepared with the following formulation using conventional materials and methods. No charge imparting substance was contained (the following parts indicate parts by weight).

Polystyrene (trade name D-125: Esso Chemical) 10
0 parts Carbon black (trade name Sieben 3500, manufactured by Cabot) 8 parts The above toner material was mixed, crushed and classified to have a particle size of 1 to 30 jua. The weight ratio of this toner and the carrier is 10:
It was mixed with lGO to prepare a developer. When the triboelectricity of this developer was measured by the blow-off method, it was -9.14c/g.
Met. Using this developer, Canon MP-500
When the image was produced using a 0 copy machine, even in a durability test of 50,000 sheets, fine line reproducibility was good, gradation was good, and there was no fogging at all.

Example 2 Polymethyl methacrylate resin 10 in xylene 11
0 g was dissolved, and 50 g of Compound Example (2) was mixed therewith. This was processed into an iron powder carrier IKg 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 carrier were mixed in the same weight ratio as in Example 1 to prepare a developer.

When the triboelectricity of this developer was measured by the blow-off method, it was -10.04 c/g. Using this developer,
When the image was produced using a Canon MP-5000 copying machine, even in a durability test of 50,000 sheets, it showed good fine line reproducibility and gradation, which were exactly the same as the initial condition, and no fogging was observed.

Example 3 10 parts of polymethyl methacrylate resin in 1 part of xylene
A solution was prepared by dissolving 0 g of the compound and mixing it with 50 g of Compound Example (3). Add Canon MP-400RE to this solution.
Dip the developing sleeve (made of stainless steel) for
The amount of compound example (3) attached to the sleeve surface is O, 1 mg/
am'' to 0.8 mg/c Peng2 to obtain a member of the present invention.

This sleeve was placed in the original developing machine.

The toner is conventionally kneaded and pulverized according to the following formulation.

Through a process such as classification, the particle size was adjusted to 1 to 30 #L.

Poly(styrene-butyl methacrylate) F&1-30
0.000 100 parts #type agent (trade name PH-130: manufactured by Hoechst) 4 parts magnetic powder (
80 copies (trade name: BL-200, manufactured by Titan Kogyo Co., Ltd.) Using this toner, an image printing durability test was conducted using MP-40ORE manufactured by Canon. After 50,000 sheets of durability, there was little change in the image from the beginning, fine line reproducibility and gradation were good, and there was no fog.

Furthermore, when the surface potential of the toner on the sleeve was measured after the end of the durability test, it was found to be -23V, confirming that the toner was completely negatively charged.

Example 4 A solution was prepared by dissolving 80 g of polycarbonate resin in 1 liter of xylene and further mixing 208 g of Compound Example (4). A developing sleeve (made of aluminum) of a developing machine for a blue cartridge for Canon PC-20 was dipped in this solution, and the amount of compound example (4) attached to the sleeve surface was 0.
．． The members of the present invention were obtained by coating at a concentration of 1 g/am2 to 0.5 g/c+s2. This sleeve was placed in the original developing machine.

On the other hand, the toner was prepared according to the following formulation, and the particle size was adjusted to 1 to 30 mm.
I finally got it together.

Poly(styrene-butyl methacrylate) FJkII-
150,ff'oo
100 parts mold release agent (trade name PH-130: manufactured by Hoechst)
4 parts Blue colorant (phthalocyanine pigment) 8 parts Using this toner, using a developing machine equipped with the above sleeve,
PC-20 was modified to enable reversal development, and durable images were produced.

When 190 g of toner was charged and a test was conducted until the toner ran out, there was no change in the image, and a clear blue image with good fine line reproducibility and gradation was obtained. Furthermore, the surface potential of the toner on the sleeve was measured and found to be -27 V, confirming the charge imparting effect.

Examples 5 to 8 Experiments were repeated in exactly the same manner as in Example 1, except that the above compound examples were changed.

[Effects of the Invention] By using the charge imparting member according to the present invention, images obtained by developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. have extremely little change in density over a long period of time, and have excellent fine line reproducibility. It has good gradation, little fogging, and can be effectively used for color development, producing extremely clear images.

Claims (2)

[Claims] (1) A charge-imparting member for developing an electrostatic image, characterized in that it has a bismuthin compound represented by the following general formula on at least its surface. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, Ar represents an aryl group or its derivative.) (2) The compound according to claim 1 is a carrier,
The charge imparting member for developing an electrostatic image according to claim 1, which is coated on a sleeve and a doctor blade.