JPS61259269A - Charge providing material for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a charge providing material capable of providing proper negative charges to a toner and having superior durability by holding a specified alkoxyguanidine on the surface of a charge providing material such as a carrier for electrostatically charging a toner. CONSTITUTION:Alkoxyguanidine represented by the formula (where R is 1-24C optionally branched alkyl) is held on the surface of a charge providing material such as iron powder, other carrier particles, a developing sleeve or a doctor blade for negatively charging a toner. The alkoxyguanidine or the compound and a resin binder are dissolved in an org. solvent, the charge providing material is dipped in the resulting soln., and the solvent is removed by evaporation to stick the compound to the surface of the charge providing material. Thus, a charge providing material withstanding friction with a toner and having superior durability is obtd., and a color image having superior fine-line reproducibility and high gradient is formed by using the charge providing material.

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 No. 2゜297.69
No. 1, #Publication No. 42-23910, and Special Publication No. 43
Various methods are described in Japanese Patent No. 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. An electrostatic latent image is formed, and then this latent image is developed and visualized using a fine powder called toner in this technology. After transferring the powder image to paper etc. as necessary, it is transferred by heat, pressure, or solvent vapor. This is to fix the problem.

The developing methods applied to these electrophotographic methods include:
Broadly speaking, there are dry development methods and wet development methods. The former is further divided into a method using a two-component developer and a method using a -component developer. Two-component developing methods include magnetic brush methods that use iron powder and carriers, depending on the type of carrier that transports the toner.

There is a cascade method using bead carriers, a fur brush method using fur, etc.

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. Particles obtained by finely pulverizing particles into particles of about 1 to 30 particles are used as toner. 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 exposed to some extent on the surface of the toner. Therefore, friction between the toners and friction between the toners and the carrier may be reduced. These additives fall off from the toner surface due to collision, friction with the electrostatic latent image carrier, etc., resulting in contamination of the carrier, etc., and contamination of the electrostatic latent image carrier 1, such as the photoreceptor belt or drum. 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-mentioned problems can be improved by improving the affinity and dispersibility of the toner binder and 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 purposes is extremely limited, and only a small number of them have been put to practical use. 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.

This method of actively imparting a charge to the toner using a charge imparting material almost eliminates the need for the toner to contain additives to improve its charging properties, thus providing an essential improvement over the above-mentioned problems. For example, sources of contamination of carrier particles, photoreceptors, etc. are essentially reduced,
Therefore, repeated development operations do not reduce the charging property or disturb the latent image, 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 electrostatic image development according to the present invention, which has been made to preferably achieve the various objects described above, is characterized by a γ-alkoxylated guanidine represented by the following chemical structural formula. (In the formula, R represents an optionally branched alkyl group having 1 to 24 carbon atoms) on at least the surface.

When the alkyl group has more than 25 carbon atoms, the effects of the present invention cannot be sufficiently obtained.

Typical specific examples of compounds used in the charge-imparting material of the present invention include the following compounds (1) to (8).

These compounds are synthesized by known methods.

For example, a methanol solution of guanidine is reacted with methylene chloride in a sealed tube, and chloromethylguanidine (Gt
By reacting H2-W-diH2-UL) with an alcohol corresponding to this chloromethylguanidine, alkoxylated methylguanidine can be obtained.

Compound Example (1) can be obtained by reacting methanol with chloroguanidine, and other compounds were obtained by a similar method.

Although it depends on the form of the charge imparting material to be applied, the compound generally has an average particle size of 10 to 0,000, particularly 2 to 0,000.
It is preferable that the charge imparting material is formed as particles of IIL, 0.01! Below 1O, the dispersibility is poor and 1O
If it exceeds IL, coating becomes difficult and causes inconvenience.

These compounds can be dissolved or dispersed in a solvent or dispersion medium together with a binder resin as necessary, and a coating solution obtained is applied to the base material of the charge-imparting material by dipping, spraying, coating, etc. When the base material is in the form of carrier particles, the above-mentioned particles are applied onto the base material by immersion mixing with the above-mentioned coating liquid and then drying, or by coating 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. In addition, it is melt-kneaded directly with the binder resin,
The charge-imparting material may be extrusion laminated onto a base material to obtain a charge-imparting material having a coating layer containing the material.Furthermore, these compounds may be incorporated into a moldable resin and then applied to carrier particles, sleeves or doctor blades. It may be formed into a shape and used as a charge imparting material.

As a binder resin or molding resin.

Common materials 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, phenol. Derivatives of resins, chlorinated paraffins, polyethylene, polypropylene, silicone resins, Teflon, etc., 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 material is 0. The range of O1 to 10 mg/crn' is good, preferably 0.1 to 2 B/ctn''.

In addition to the above-mentioned compounds, ceramic powders such as silica powder, aluminum oxide, cerium oxide, and silicon carbide may also be used as fillers, and conductive agents such as carbon black and tin oxide may be used as fillers. Further, 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 containing metal oxides, as well as glass, SiC, BaTiO2, 5R
Ceramic powder or particles such as TiO2 are used. Also, those whose surfaces are treated with resin etc.

Examples include resin powder or resin powder containing a magnetic substance. The average particle size is preferably about 20 to 250 l.

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,
Furthermore, these toners may contain magnetic powder for more effective charging.

It may contain small amounts of charge-imparting substances 1, such as dyes, pigments, or so-called charge control agents, as well as fluidizing agents such as colloidal silica, abrasives such as cerium oxide, strontium titanate, and silicon carbide, and metal stearates. It may contain lubricants such as salts and vinylidene fluoride, and may also contain conductivity imparting agents such as carbon black and tin oxide.

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, as shown in the examples below, the compound of the present invention not only has excellent charge control properties and stability against heating and moisture absorption, but also has the ability to be coated or kneaded onto 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 provided. Therefore, by using this charge-imparting material, it is possible to obtain a substantial improvement over the various problems that occur when the charge-imparting material is mixed only into toner to improve its charging characteristics.

[Embodiments of the invention]

Example 1 Methyl ethyl ketone (NEK Monthly Chinese Compound (1)
Dissolve and disperse 100g of iron powder carrier (particle size;
250-400mesh) was dispersed and stirred 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 product carrier was prepared without adding compound (1) in the above procedure.

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 kneaded, crushed, and classified to have a particle size of 1 to 30 mm.

This toner and each of the above carriers were mixed in a weight ratio of 10:100.
This 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 product -0.5 gc/g When images were produced using a Canon NP-5000 copying machine using these developers, the product of the present invention produced an image of 50.0 gc/g.
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, the comparative product showed a change in image density after several sheets.

Example 2 Polymethyl methacrylate resin 10 in xylene lfL
0 g was dissolved, and 50 g of compound (1) 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 -11.2hc/g, and when an image was created using this, the resulting image was as follows:
Even in a durability test of 50,000 sheets, it exhibited good image density, fine line reproducibility, and 5-tone gradation, the same as the initial condition, and no fogging.

Example 3 Polymethyl methacrylate resin 100 in xylene 1i
A solution was prepared by dissolving 50 g of compound (2). A developing sleeve (made of stainless steel) for Canon MP-400RE was dipped in this solution, and a coating of 0.1 to 0.8 g/crn' 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 (2) 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 mixing and pulverizing method.

Poly(styrene-butyl methacrylate) 100 parts Fa
w = 300,000 Mold release agent (trade name PE-130: manufactured by Hoechst) 4
Part magnetic powder (product name BL-200: manufactured by Titan Kogyo Co., Ltd.) BO
The particle size of the prepared toner was adjusted to 1 to 30 IL.

Using this toner, an image reproduction durability test was conducted using Canon NP-400RE. After 50,000 sheets of durability, there was no change in the image from the beginning, fine line reproducibility, single gradation performance was good, and there was no fog.

On the other hand, the comparative product showed a change in image density after several sheets.

In addition, when the surface potential on the sleeve was measured, it was -32V (inventive product) (Example 3), -32V (comparison product), and 5V (example 3), confirming that the toner in the inventive product was completely negatively charged. .

Example 4 A solution was prepared by dissolving 80 g of polycarbonate resin in one bottle of xylene and further mixing 20 g of compound (2).

A developing sleeve (made of aluminum) of a developing machine for a blue cartridge for Canon PC-20 was dipped in this solution, and a 0.1 to 0.5 layer g/cm'' coating was applied on the sleeve.

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 1IL to 30IL.

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, the image does not change until the toner runs out.
A clear blue image with good fine line reproducibility and gradation was obtained. Furthermore, when we measured the surface potential of the toner on the sleeve, we found that -
It was 40V and negatively charged.

Examples 5-8 Compound (1) used in Example 1.2 was converted into compound (
Example 5.6 was carried out in the same manner as in Example 1.2, except that compound (2) used in Example 3.4 was replaced with compound (4). , Example 7.8 was carried out in the same manner as Example 3.4. The results were good, and the corresponding triboelectric charge amount and surface potential were as follows.

Example 5 -8.2 Cog tt 6 -7.91 LC/g/l 7 -33 V // 8 -39 V Examples 9 to 12 The compound (1) used in Example 1.2 was converted to the compound (
Examples 9 and 10 were carried out in the same manner as in Example 1.2, except that compound (2) used in Example 3.4 was replaced with compound (6). , Example 11.12 was carried out in a similar manner to Example 3.4. The results were good, and the corresponding triboelectric charge amount and surface potential were as follows.

Example 9 -10.3Cog // 10 -7.11LC/g/l 11 -21 V // 12 -28 V Examples 13 to 16 Compound (1) used in Example 1.2 was converted to compound (
Example 13.14 was carried out in the same manner as in Examples 1 and 2, except that compound (2) used in Example 3.4 was replaced with compound (8). ,
Examples 15 and 16 were carried out in the same manner as in Examples 3 and 4. The results were good, and the corresponding triboelectric charge amount and surface potential were as follows.

Claims (4)

[Claims] (1) Alkoxylated guanidines represented by the chemical structural formula below ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents an optionally branched alkyl group having 1 to 24 carbon atoms) at least on the surface A charge imparting material for developing an electrostatic image, comprising: (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.