JPS61259262A - Charge providing material for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a charge providing material capable of providing proper electric charges to a toner and having superior durability by holding a specified dicyclohexylamine nitrite on the surface of a charge providing material such as carrier particles for providing electric charges to a toner. CONSTITUTION:Dicyclohexylamine nitrite represented by the formula (where each of R, R', R'' and R''' is <=20C alkyl, aryl, alkoxy, acyl, halogen or NO2, but the substituents may not by present) is held on at least the surface of a charge providing material such as carrier particles, a cylindrical sleeve or a doctor blade for providing electric charges to a toner which develops an electrostatic charge image in an electrophotographic process, an electrostatic recording process or other process. The dicyclohexyamine nitrite 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 attaining the proper electrostatic charging of a toner and having superior durability to friction with the 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 No. 2゜297.69
1, 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 on a photoconductive insulating layer and irradiate the insulating layer with a light image to generate static electricity. An electrostatic latent image is formed, and then this latent image is developed and visualized using a fine powder called toner using the relevant technology. After transferring the powder image to paper or the like as necessary, it is fixed by heating, pressure, or solvent vapor. This is what we do.

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. Depending on the type of carrier that transports the toner, there are two-component developing methods:
There are magnetic brush methods using iron powder and carriers, cascade methods using beads and carriers, and fur brush methods using fur.

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 an electrostatic latent image.

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 IL 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 impart charge to the toner, it is possible to utilize only the triboelectricity of the resin, which is a component of the toner, but with this method, the toner has a low chargeability, so the image obtained by development is prone to fogging. It becomes unclear. 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 holding member 1, such as the photoreceptor belt or drum, etc. occur. As a result, the charging property deteriorates, and as development operations are repeated, deterioration progresses, image density decreases, fine line reproducibility decreases, fog increases, etc., which pose practical problems.

The above-mentioned problems can be improved by improving the affinity 1 dispersibility of the toner binder with additives such as dyes and pigments that impart chargeability or charge control agents. Therefore, surface treatment often results in a decrease in charge imparting properties, and if mechanical shear is strongly applied and finely dispersed, the proportion of additives that appear 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, rather than improving the charge imparting characteristics to toner by using toner additives alone,
Conveyance, regulation, or friction members such as carriers, sleeves, and doctor blades that come into contact with toner during the development process (hereinafter referred to as "charge imparting materials") that come into contact with toner during or prior to the development process, A general term for materials or members that can provide the toner with the charge necessary for development or provide an auxiliary charge)
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, contamination sources such as carrier particles and photoreceptors are reduced in a wood-based manner,
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.

The 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 member suitable for charging color toner.

[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 above-mentioned various objects, is characterized by dicyclohexylamine nitrite represented by the following chemical structural formula [wherein R, R", R" Rst represents an alkyl group (not more than 20 carbon atoms), a 7-aryl group, an alkoxy group, an acyl group, a halogen atom, or a nitro group, but these substituents may not be present] on at least the surface. There it is.

Typical specific examples of compounds used on the surface of the charge imparting material of the present invention include the following compounds (1) to (8).
can be mentioned.

These compounds are extremely stable and can be synthesized by known methods.

For example, compound example (1) is dicyclohexylamine (
(manufactured by Kishida Chemical Co., Ltd.) by adding a nitrous acid aqueous solution, and commercially available f) T-V-IC'
JIRWR'14; ((C6J, 1)2NH-HIO
2) +Manufactured by Rest Kagaku Co., Ltd.) may be used. In the present invention, dicyclohexylamine nitrite represented by the above chemical structural formula has up to 20 carbon atoms when an alkyl group is used as a substituent, If the number of carbon atoms is more than that, a sufficient effect cannot be obtained.

The above compound generally has an average particle size of lθ to 0.01 g, particularly 2 to 0.01 g, although it depends on the form of the charge imparting material to be applied.
It is preferable to use the particles in the form of a charge imparting material in the form of particles of 1 liter.

These compounds can be dissolved or dispersed in a solvent or dispersion medium together with a binder resin if necessary, and a coating liquid obtained can be applied to the base material of the charge imparting material by dipping, spraying, coating, etc. Alternatively, if the base material is in the form of carrier particles, the base material may be coated on the base material by immersion mixing with the above coating liquid and then drying, or by coating with a fluidized bed of a direct mixture of this and the above compound. The charge-imparting material of the present invention can be obtained by forming a coating layer of the above-mentioned compound on the substrate. Alternatively, the material may be directly melt-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.

Furthermore, these compounds may be contained in a moldable resin and molded into the shape of carrier particles, sleeves, or doctor blades to form a charge-imparting material.

As a binder resin or molding resin.

For example, 8 common ones can be used.

Polystyrene, polyacrylic acid ester, polymethacrylic acid ester, polyacrylonitrile, rubber resins such as isoprene and butadiene, polyester, polyurethane, polyamide, epoxy resin, rosin, polycarbonate, phenolic resin, chlorinated paraffin, polyethylene.

Derivatives thereof such as polypropylene, silicone resin, Teflon, 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 content of the material is preferably in the range of 0.01 to 10g/c, but
Preferably it is 0.1 to 2 mg/crn'.

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.

As a base material for charge imparting material in carrier form.

All known carriers can be used; powders or particles of metals such as iron, nickel, aluminum, copper or alloys or metal compounds including metal oxides;
Furthermore, glass, SiC, BaTiO2, 5rTi02
, and other ceramic powders or particles 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 one aspect of the present invention, there is provided a charge imparting material for imparting a charge to a toner for developing an electrostatic image, 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 provided. 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.

[Embodiments of the invention]

Example 1 Methyl ethyl ketone (MEK) 1! 100 g of the compound (1) was dissolved and dispersed in L, 1 kg of iron powder carrier (particle size: 250 to 400 mesh) was dispersed therein, and the mixture was stirred in a ball mill for about 30 minutes.

After drying this iron powder carrier mixture and completely removing 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 m.

The weight ratio of this toner and each of the above carriers is 10:
The mixture was mixed with too much to prepare a developer.

When the amount of triboelectric charge of these developers was measured by the blow-off method, the results were as follows - Comparative product -
When images were produced using a Canon MP-5000 copying machine using these developers, the product of the present invention produced an image of 50.0 C/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 3,000 sheets.

Example 2 Polymethyl methacrylate resin 100 in xylene 11
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 -9 gC/g, and when an image was created using this, the resulting image was 50,
Even in a durability test of 1,000 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% xylene
A solution was prepared in which 50 g of compound (1) was mixed with 50 g of compound (1). A developing sleeve (made of stainless steel) for Canon MP-400RE was dipped in this solution, and the sleeve was coated at a concentration of 0.1 to 0.8 mg/arrI'.

In addition, in order to compare with the product of the present invention, a comparative sleeve was prepared without adding compound (1) 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 M = 300,000 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 IL.

Using this toner, a durability test was conducted using Canon MP-400RE. 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, the comparative product showed a change in image density after 3000 sheets.

Further, when the surface potential on the sleeve was measured, it was -30V for the product of the present invention (Example 3) and -7V for the comparative product, confirming that the toner in the product of the present invention was completely negatively charged.

Example 4 A solution was prepared by dissolving 80 g of polycarbonate resin in one drop of xylene and further mixing 20 g of compound (1).

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 coating of 0.1 to 0.5 g/am'' was applied onto 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) Part B: 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
'-30V and negatively charged φ Examples 5 to 8 Same as Examples 1 to 4 except that each compound (1) used in Examples 1 to 4 was replaced with compound (2). Examples 5 to 8 were carried out according to the order of operations. The results were good, and the amount of triboelectric charge and surface potential measured accordingly were as follows.

Example 5 -9 final C/g tt 6 - 71LC/g //7-32V //8-28V Examples 9-12 In Examples 1-4, each compound (1) used was replaced with compound (3) Examples 9 to 12 were carried out in the same order as in Examples 1 to 4, except that . The results were good, and the amount of triboelectric charge and surface potential measured accordingly were as follows.

Example 9 -10 Cog/l 10-8 Cog/l 11 -36 V // 12 -30 V Examples 13 to 16 In Examples 1 to 4, each compound (1) used was replaced with the compound Examples 13 to 15 were carried out in the same order as in Examples 1 to 4, except that (5) was replaced. The results were good, and the amount of triboelectric charge and surface potential measured accordingly were as follows.

Example 13 -111Lc/g //14-8 Cog /l 15 -33 V /l 16 -28 V

Claims (4)

[Claims] (1) Dicyclohexylamine nitrite represented by the chemical structural formula below ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ [In the formula, R, R', R'', R''' are alkyl groups (20 or less carbon atoms) , represents an aryl group, an alkoxy group, an acyl group, a halogen atom or a nitro group. However, these substituents may not be present in some cases. (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.