JPS61258270A - Charge providing material for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To prevent deterioration in the performance of a charge providing material by use for a long period by holding a specified compound on at least the surface of the charge providing material. CONSTITUTION:A compound represented by the formula is held on at least the surface of a charge providing material. The compound is obtd. as a white precipitate by dissolving a halide of the corresponding ammonium salt and dropping an aqueous soln. of hexafluorophosphoric acid into the resulting soln. The compound represented by the formula is generally used in the form of particles of 10-0.01mum average particle size. Polystyrene, polyacrylate or the like can be used as a binding or molding resin, and the resin is used so that the amount of the compound is regulated to 0.5-200pts.wt. per 100pts.wt. resin. When the compound is applied to the surface of the charge providing material, it is preferably applied by 0.01-10mg/cm<2>. Thus, a satisfactory charge providing material having superior durability during use under friction with a toner is obtd.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides an improved function for imparting charge to toner used for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. Related to materials or members.

[Background of the invention]

Conventionally, as an electrophotographic method, U.S. Patent I12゜297.6
91, Special Publication No. 42-23910, and Special Publication No. 4
Various methods are described in Japanese Patent No. 3-24748, etc., but they basically involve applying a uniform electrostatic charge onto a photoconductive insulating layer and irradiating the insulating layer with a light image. to form an electrostatic latent image, and then this latent image is developed and visualized using fine powder called toner in this technology, and if necessary, after transferring the powder image to paper etc., heating, pressurization, solvent vapor, etc. Fixation is carried out by

The developing methods applied to these electrophotographic methods include:
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, depending on the type of carrier for conveying the toner, a magneto-two brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, and the like.

In addition, methods belonging to the -component development method include the powder cloud method, in which toner particles are sprayed, and the contact development method (contact development, or toner development method, in which toner particles are brought into direct contact with the electrostatic latent image surface for 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; magnetic conductivity; There is the MagneDry method, which develops by bringing toner into contact with the electrostatic latent image surface.

Conventionally, toners used in these development methods are fine powders in which dyes and pigments are dispersed in natural or synthetic resins. Finely pulverized particles of about 1 to 30 liters are used as toner. Also, as magnetic toners, those containing magnetic particles such as magnetite instead of or in addition to the dyes or pigments described above are used.

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

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

In order to charge the toner, it is also possible to use only the triboelectricity of the resin that is a component of the toner, but with this method, the toner's chargeability is small, so the image obtained by development is prone to fogging and is unclear. Become something. Therefore, in order to impart desired triboelectric charging properties to the toner, charge control agents such as dyes and pigments that enhance the charging properties are added.

However, in order to impart chargeability to the toner by adding these additives.

These additives must be present on the surface of the toner to some extent. Therefore, these additives fall off from the toner surface due to friction between the toners, collision with the carrier, friction with the electrostatic latent image holder, etc. Contamination of the carrier, etc., and contamination of the electrostatic latent image carrier, such as the photoreceptor belt or drum, etc. occur. As a result, the charging property deteriorates, and as development operations are repeated, the deterioration progresses, resulting in a decrease in image density, a decrease in fine line reproducibility, an increase in fog, and other practical problems.

The above problems can be improved by improving the compatibility and dispersibility of the toner binder with additives such as dyes and pigments that impart chargeability or charge control agents. Surface treatment to increase the toner often results in a decrease in charge imparting properties, and if mechanical shear is strongly applied and finely dispersed, the proportion of the additive that appears on the toner surface decreases, resulting in a tendency for insufficient chargeability to be imparted. . For these reasons, ``The number of additives that can impart chargeability to toner to a level that is sufficiently satisfactory for practical use is extremely limited, and only a few have been put into practical use, especially for monochrome images.'' Rather, in order to obtain a color image, it is preferable that the charge control agent added to the toner be colorless, and in this case, there are almost no practically satisfactory charge control agents.

In view of these circumstances, the improvement of the charge imparting characteristics to toner is not only achieved by toner additives, but also by improving the conveyance, regulation, or friction of carriers, sleeves, doctor blades, etc. that come into contact with toner during the development process. A member (hereinafter collectively referred to as a "charge-imparting material") that comes into contact with the toner during or prior to the development process, and can impart a charge necessary for development to the toner, or can provide an auxiliary charge to the toner. (collectively refers to materials or parts)
It has also been proposed to improve the charge imparting characteristics to toner.

With this method of actively imparting charge to the toner using a charge imparting material, there is almost no need to include additives in the toner to improve charging characteristics, so it is possible to improve the quality of the toner to address the above-mentioned problems. For example, contamination sources such as carrier particles and photoreceptors are reduced in a wood-based manner,
Therefore, the chargeability does not decrease or the latent image is not disturbed due to repeated development operations, and furthermore, the color toner can be easily charged without damaging its tone.

However, charge-imparting materials such as carriers, sleeves, and doctor blades must not only have strong charge-imparting ability, but also be durable and able to withstand friction with toner. For example, carriers must be replaced over a long period of time. In addition, the sleeve is required to have the same degree of durability as the main body of the developing machine.

[Purpose of the invention]

The present invention has been made in order to provide a charge imparting material that solves the above-mentioned problems, and its purpose is to provide a charge imparting material that imparts an appropriate negative charge to toner.

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

A further object of the present invention is to provide a charge-imparting material that provides images with excellent fine line reproducibility and gradation.

A further object of the present invention is to provide a charge imparting material suitable for charging color toners.

[Summary of the invention]

The charge imparting material for developing electrostatic images according to the present invention, which has been made to preferably achieve the above-mentioned various objects, is characterized by a compound 1+ R2-N-R4py6 (in the formula , R1-R4 represent hydrogen, an alkyl group, an aralkyl group, or an aryl group having 30 or less carbon atoms, or a derivative having these as the basic skeleton, and may be the same or different from each other). It's on the surface.

Typical specific examples of compounds used in the charge-imparting material of the present invention include the following compounds (1) to (10).

" 2H5 M3 These compounds are synthesized by known methods.

For example, compound (1) is produced as follows.

That is, an aqueous solution of hexafluorophosphoric acid is added dropwise to a solution in which a halide of the corresponding ammonium salt is dissolved, and
Obtain the object by scuttling it.

The above compound generally has an average particle size of 10 to 0.011L, particularly 2 to 0.01L, although it depends on the form of the charge imparting material to be applied.
It is preferable to use the particles of IIL to form a charge imparting material.

These compounds can be dissolved or dispersed in a solvent or dispersion medium together with a binder resin if necessary, and then a coating liquid obtained is applied to the base material of the charge imparting material by dipping, spraying,
It can be applied by brushing, etc., or if the base material is in the form of carrier particles, it can be immersed and mixed with the above-mentioned coating liquid and then dried, or it can be coated with a fluidized bed of a direct mixture of this and the above-mentioned compound. The charge-imparting material of the present invention can be obtained by forming a coating layer of the compound on a base material by the method described above. Alternatively, the charge imparting material may be directly melted and kneaded with a binder resin and extruded and laminated onto a base material to obtain a charge imparting material having a coating layer containing the material.Further, these compounds may be contained in a moldable resin. This may be formed into the shape of carrier particles, sleeves, or doctor blades to serve as a charge-imparting material.

As the binder resin or molding resin, common resins can be used. For example, polystyrene, polyacrylic ester, polymethacrylic ester, polyacrylonitrile, rubber resins such as isoprene and butadiene, polyester, polyurethane, polyamide. , epoxy resin, rosin, polycarbonate, phenolic resin, chlorinated paraffin, polyethylene, polypropylene, silicone resin, Teflon, derivatives thereof, copolymers thereof, or mixtures thereof can be used.

After coating or molding, these resins can be made to have a crosslinked structure as necessary to improve the durability of the surface layer of the charge-imparting material.

When a binder resin or a molding resin is used, it is preferable to use the compound in a ratio of 0.5 to 200 parts, particularly 2 to 100 parts, based on 100 parts by weight (the same applies hereinafter).

When coating the surface of the charge imparting material, it is necessary to appropriately control the coating or coating amount of the compound, but
The above material is 0.0! ~ IOB/crn', preferably 0.1 to 2 mg/ctn''.

'Also, throughout the above series of cases, along with the compound,
Ceramic powders such as silica powder, aluminum oxide, cerium oxide, and silicon carbide may be used as fillers, and conductivity imparting agents such as carbon black and tin oxide may be used to adjust conductivity. In order to prevent the spent toner from being deposited on the sleeve or carrier surface, a release agent such as a fatty acid metal salt, vinylidene fluoride, etc. may be used.

All known carriers can be used as the base material for the charge imparting material in carrier form.

Powder or particles of metals or alloys such as iron, nickel, aluminum, copper, or metal compounds including metal oxides, and even glass.

Ceramic powder or particles such as Sic, BaTiO2, 5rTi02, etc. are used. Further, examples include those whose surfaces have been treated with a resin, resin powder, or resin powder containing a magnetic material. The average particle size is preferably about 20 to 250 IL.

Furthermore, the base material of the charge imparting material in the form of a sleeve or doctor blade may generally be metals or alloys such as iron, aluminum, stainless steel, or nickel, or non-metallic compounds such as ceramics or plastics, which can be used as a sleeve or doctor blade. can be used.

On the other hand, as toners to be used in combination with the charge imparting material of the present invention as described above, substantially all toners that have been used as conventional toners for developing electrostatic images can be effectively used. That is, both non-magnetic and magnetic toners can be used. More specifically, the toner is a colored fine particle containing a colorant in a binder resin, and if necessary,
These toners may contain magnetic powder, and may also contain small amounts of charge-imparting substances such as dyes, pigments, or so-called charge control agents in order to impart more effective charge. It may contain a fluidizing agent such as silica, an abrasive agent such as cerium oxide, strontium titanate, and silicon carbide, a lubricant such as metal stearate, and vinylidene fluoride, and a conductive material such as carbon black and tin oxide. It may also contain a imparting agent.

As the developing method using the charge imparting material and toner of the present invention described above, substantially all developing methods using a two-component developer or a single-component developer can be used.

For example, magnetic brush development method, cascade development method, fur brush development method, so-called microtoning development method using magnetic substance-containing resin powder as a carrier, development method using resin powder as a carrier, so-called jumping development method, or non-magnetic This is a jumping development method that develops toner.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a charge imparting material for imparting charge to an electrostatic image developing toner, which has a compound having a specific structure as a charge control agent on its surface. In particular, one compound of the present invention not only has excellent charge control properties and stability against heating and moisture absorption, as shown in the following examples, but also has the ability to coat or knead into the surface of a charge-imparting material. When present by dispersion or the like, a good charge imparting material with excellent durability when used in friction with toner can be obtained. Therefore, by using this charge-imparting material, it is possible to obtain a physical improvement over the various problems that occur when the charge-imparting material is mixed only into toner to improve its charging characteristics.

[Examples of the invention] Example 1 The above compound (
1) was dissolved and dispersed, and Ikg of iron powder carrier (particle size: 250-400ve+h) was dispersed therein, followed by stirring in a ball mill for about 30 minutes.

After drying this iron powder carrier mixture to completely remove the solvent, light agglomerations were loosened to obtain a carrier-like charge imparting material according to the present invention.

In addition, in order to compare with the product of the present invention, a comparative amount carrier was prepared without adding compound (1) in the above operation.

Separately, a toner was prepared according to the following formulation without adding any charge control agent.

Styrene 100 parts (trade name D-125, manufactured by Esso Chemical Co., Ltd.) Carbon black 6 parts (trade name Raven 3500, manufactured by Capot Co., Ltd.) The above materials were mixed, crushed, and classified to have a particle size of 1 to 30 pm.

This toner and each of the above carriers were mixed in a weight ratio of 10:100.
was mixed to prepare a developer.

The amount of triboelectric charge of these developers was measured by the blow-off method and was as follows.

Comparative amount -2 kclg When images were produced using a Canon MP-5000 copying machine using these developers, the product of the present invention had a value of 50.0.
Even in a durability test of 00 sheets, there was no change in image density, fine line reproducibility was good, and gradation was also good. There was also no fog. On the other hand, with the comparative amount, a change in image density occurred after 3,000 sheets.

Example 2 100% polymethyl methacrylate resin in 1 bottle of xylene
g was dissolved, and 50 g of compound (2) was further mixed therein. This was mixed with the same iron powder carrier as in Example 1 and dried to obtain a carrier having a charge imparting effect.

When this was used in combination with a toner in the same manner as in Example 1, the amount of triboelectric charge of the toner was 113 C/g, and when an image was produced using this, the resulting image was 50
Even in a durability test of ,000 sheets, the image density, fine line reproducibility, and gradation were as good as the initial state, and there was no fog.

Example 3 100% polymethyl methacrylate resin in 1 bottle of xylene
A solution was prepared by dissolving 50 g of compound (3). A developing sleeve (made of stainless steel) for Canon NP-40QRE was dipped in this solution, and a coating of 0.1 to 0.6 mg/cm'' was applied onto the sleeve.

In addition, in order to compare with the product of the present invention, a comparative sleeve was prepared without adding compound (3) in the above procedure.

These sleeves were placed in the original developing machine. The toner was prepared according to the following recipe using a general kneading and pulverizing method.

Poly (styrene-butyl methacrylate) 100
Part Flow = 30.0.000 Mold release agent (trade name PE-130: manufactured by Hoechst) 4
Part magnetic powder (trade name BL-200: manufactured by Titan Kogyo Co., Ltd.) 80
The particle sizes of the prepared toners were adjusted to 1 l to 30 l.

Using this toner, an image printing durability test was conducted using Canon MP-40ORE. After 50,000 sheets of durability, there was no change in the image from the beginning, fine line reproducibility and gradation were good, and there was no fog.

On the other hand, with the comparative amount, a change in image density occurred after 3,000 sheets.

Further, when the surface potential on the sleeve was measured, it was -29V for the product of the present invention (comparison with Example 3) -7V, confirming that the toner of the product of the present invention was completely negatively charged.

Example 4 80g of polycarbonate resin was dissolved in 1 bottle of xylene, and 20g of compound (4) was further mixed to make Kaya Shukuda: lf
+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 sleeve was coated with O91 to 0.5 g/crf.

This sleeve was placed in the original developing machine.

On the other hand, a toner was prepared according to the following recipe.

Poly(styrene-butyl methacrylate) 100 parts Mw
= 150.000 Mold release agent (trade name PE-130: manufactured by Hoechst) 4
Part Blue colorant (phthalocyanine pigment) 6 parts The prepared toner had a particle size of 1 p to 30 g.

Using this toner, a PC-20 was modified to enable reversal development using a developing machine equipped with the above-mentioned sleeve, and durable images were produced.

As a result, there is no change in one image until the toner runs out.
A clear blue image with good fine line reproducibility and single gradation was obtained. Furthermore, when we measured the surface potential of the toner on the sleeve, we found that -
It was 33V and negatively charged.

Examples 5 to 8 Examples 5 to 8 were carried out in accordance with the procedures of Examples 1 to 4, with the respective compounds used in Examples 1 to 4 being replaced as shown below.

Compound (1) → (5) Example 5 tt (2) → ([j) // 5〃(3)
→(7) tt 7 〃(4)→(8) // 8 The results were good, and the correspondingly measured triboelectric charge amount and surface potential were as follows.

Example 5 -11kC/g //6 -14 Cog 7-35V per house //8 -32V

Claims (4)

[Claims] (1) Compounds represented by the chemical structural formula below ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 to R_4 are hydrogen or have 3 carbon atoms.
0 or less alkyl group, aralkyl group, or aryl group, or a derivative having these as a basic skeleton, which may be the same or different) on at least the surface. Charge imparting material for use. (2) The charge imparting material for developing an electrostatic image as set forth in claim (1), wherein the charge imparting material is carrier particles. (3) The charge imparting material for developing an electrostatic image as set forth in claim (1), wherein the charge imparting material is a cylindrical sleeve. (4) The charge imparting material for developing an electrostatic image as set forth in claim (1), wherein the charge imparting material is a doctor blade.