JPS61260256A - Electric charge applying material for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain an electric charge applying material which applies adequate negative charge to a toner by incorporating a specific guanidine at least into the surface thereof. CONSTITUTION:This material has the guanidine expressed by the formula at least on the surface. (In the formula, R1, R2 denote a hydrogen atom, halogen atom, alkyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, aralkyloxy group, aralkylthio group, arylthio group, aralkylthio group or nitro group which may be the same or different). The alkyl chain or aryl ring may be substd. Such compd. is exemplified by the compds. expressed by formulas (1)-(4). The compd. is preferably used in the form of particles having generally 10-0.01mu, more particularly 2-0.1mu average grain size for forming the electric charge applying material although the grain size varies with the form of the charge applying material for which the compd. is to be applied. General resins are usable as the binder resin or molding resin to be used with the compds.

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 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 for conveying the toner.

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 liters are used as toner. Also, as a magnetic toner, instead of the dye or pigment described above.

Alternatively, in addition to this, a material containing magnetic particles such as magnetite is 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 exposed to some extent on the surface of the toner. Therefore, friction between the toners, collision with the carrier, and static These additives fall off from the toner surface due to friction with the electrostatic latent image carrier, 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, deterioration progresses, image density decreases, fine line reproducibility decreases, fog increases, etc., which pose practical problems.

The problem mentioned above is with the toner binder.

This can be improved by improving the affinity and dispersibility with additives such as dyes and pigments that impart chargeability or charge control agents; however, surface treatment to increase affinity for these additives reduces chargeability. In many cases, if strong mechanical shearing is applied to finely disperse the toner, the proportion of the additive appearing on the toner surface decreases, and there is a tendency that sufficient charging properties are not imparted. For these reasons, the number of additives that can impart chargeability to toner to a level that satisfies the needs of practical use is extremely limited, and only a few have been put into practical use, especially for monochrome images. In addition, 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 the charge necessary for development to the toner or provide an auxiliary charge to the toner. It has also been proposed to improve the charge imparting characteristics to the toner by using (hereinafter referred to as a general term for all members).

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 member suitable for charging color toner.

[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 guanidine compound represented by the following chemical structural formula [where RI + R2 is hydrogen atom, halogen atom,
represents an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, an arylthio group, an aralkylthio group, or a nitro group, which may be the same or different; chain, aryl ring may be substituted] on at least the surface.

The substituents R1+R2 in the structural formula (1) include a hydrogen atom, a halogen atom such as a chlorine atom, a bromine atom, and an iodine atom, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and a dodecyl group. Alkyl groups that may be branched such as groups, substituted alkyl groups such as methoxyethyl group, ethoxyethyl group, butoxyethyl group, chloroethyl group, dimethylaminoethyl group, phenyl group, tolyl group, butylphenyl group, butoxyphenyl group , heptaryl groups such as chlorphenyl groups, heptaralkyl groups such as benzyl groups, phenethyl groups, methylbenzyl groups, alkoxy groups such as methoxy groups, ethoxy groups, propoxy groups, butoxy groups, octoxy groups, phenoxy groups, chlorophenoxy groups 7-aryloxy groups such as benzyloxy groups, methylbenzyloxy groups, chlorobenzyloxy groups, aralkyloxy groups such as phenethyloxy groups, alkylthio groups such as methylthio groups, propylthio groups, hexylthio groups, phenylthio groups, methylphenylthio groups , ethylphenylthio group, 7-arylthio group such as chlorphenylthio group, benzylthio group.

Representative substituents include aralkylthio groups such as chlorobenzylthio group and methylbenzylthio group, and nitro group.

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

These compounds are synthesized by known methods.

That is, it is generally synthesized by reacting a 2-chlorobenzol derivative corresponding to guanidine (H2N-C-Nl2).

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 form the charge imparting material in the form of particles of 1 h. If the particle size is less than 1 h, the dispersibility will be poor and the effect will be reduced. Further, if the amount is 1 OIL or more, coating becomes difficult and causes inconvenience.

These compounds can be dissolved or dispersed in a solvent or dispersion medium together with a binder resin if necessary, and a coating solution obtained is applied to the base material of the charge-imparting material by dipping, spraying, brushing, etc. Alternatively, if the base material is in the form of carrier particles, it can 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. By forming a coating layer of the above compound, the charge imparting material of the present invention can be obtained. Alternatively, the charge-imparting material may be directly melt-kneaded with a binder resin and extrusion laminated onto a base material to obtain a charge-imparting material having a coating layer containing the material. This may be formed into the shape of carrier particles, sleeves, or doctor blades to be used as a charge-imparting material.

As the binder resin or molding resin, common resins can be used, such as polystyrene, polyacrylic ester, polymethacrylic ester, polyacrylonitrile, rubber resins such as isoprene and butadiene, polyester, polyurethane, polyamide,
Epoxy resins, rosins, polycarbonates, phenolic resins, chlorinated paraffins, polyethylene, polypropylene, silicone resins, 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 material is 0. O is preferably in the range of 1 to 10 mg/am'', preferably 0.1 to 2 mg/am''.

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 of the charge imparting material in carrier form, and metals such as iron, nickel, aluminum, copper, alloys, or powders of metal compounds containing metal oxides can be used. Particles, and further ceramic powders or particles such as glass, 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, as the base material of the charge imparting material in the form of a sleeve or doctor blade, materials such as gold or alloys such as iron, aluminum, stainless steel, and nickel, non-metallic compounds such as ceramics and plastics, etc. can generally be used as the 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, 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 obtained. 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 1 100 g of the compound (1) was dissolved and dispersed in 1 i of methyl ethyl ketone (MEK), and 1 kg of iron powder carrier (particle size: 25 G to 40 Omesh) 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 350O: manufactured by Capot Co., Ltd.) The above materials were mixed, crushed, and classified to have a particle size of 1 to 30 ILm.

The weight ratio of this toner and each of the above carriers is 10:
100 to prepare a developer.

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

Comparison amount -0.5 final Cog When images were produced using a Canon MP-5000 copying machine using these developers, the product of the present invention had a final Cog 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, the comparative amount caused a change in image density after several sheets.

Example 2 Polymethyl methacrylate resin 10 in 1 xylene
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 -7.31LC/g, and when an image was created using this, the obtained image was as follows.
Even in a durability test of 50,000 sheets, it exhibited good image density, fine line reproducibility, and single gradation, just like the initial state, and no fogging.

Example 3 100% polymethyl methacrylate resin in 1 bottle of xylene
A solution was prepared in which 50 g of compound (2) was mixed with 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/c rn' was applied onto the sleeve.

In addition, in order to compare with the product of the present invention, a sleeve was prepared in a comparative amount 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 Mw = 300,000 Mold release agent (trade name PH-130: manufactured by Hoechst) 4
Part magnetic powder (product name BL-200: manufactured by Titan Kogyo Co., Ltd.) 60
The particle sizes of the prepared toners were adjusted to 1IL to 30IL.

Using this toner, an image reproduction 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, single gradation performance was good, and there was no fog.

On the other hand, the comparative amount caused a change in image density after several sheets.

Further, when the surface potential on the sleeve was measured, it was -42V for the product of the present invention (Example 3) -5V for comparison, and it was confirmed that the toner of 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 bottle of xylene and further mixing 20 g of compound (2).

A developing sleeve (made of aluminum) of a developing machine for blue cartridge for Canon PC-20 was dipped in this solution, and the sleeve was coated with O0l~Q, 5 B/crn'.

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) ioo
Part M support = 150,000 Mold release agent (product name PE-130: manufactured by Hoechst) 4
Part Blue colorant (phthalocyanine pigment) 8 parts The prepared toner had a particle size of 1 to 30 L.

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 28V and negatively charged.

Examples 5 to 8 Examples 5 and 6 were carried out in the same manner as in Examples 1 and 2, except that each compound (1) used in Example 1.2 was replaced with compound (3), Further, Examples 7 and 8 were carried out in the same manner as in Examples 3 and 4, except that each compound (2) used in Examples 3 and 4 was replaced with compound (4). The results were good, and the amount of triboelectric charge and surface potential measured accordingly were as follows.

Example 5 -11.2 μC/g tt 5 -9.3 pot C/g //7-42V //8-28V Examples 9 to 12 In Example 1.2, each compound (1) used was Examples 9 and 1o were carried out in the same manner as in Example 1.2 except that compound (5) was substituted, and in Example 3.4, each compound (2) used was replaced with compound (6). Example 11.1 was carried out in the same manner as in Example 3.4 except that
2 was carried out. The results were good, and the amount of triboelectric charge and surface potential measured accordingly were as follows.

Example 9 -13.31Lc/g // 10 - 9.8HiroC/g // 1l-40V // 12 -33V Examples 13 to 16 Each compound (1) used in Example 1.2 Example 13.14 was carried out in the same manner as in Example 1.2, except that , was replaced with compound (7), and in Example 3.4, each compound (2) used was replaced with compound (7). Example 15.8) was prepared in the same manner as in Example 3.4 except that 8) was replaced.
16 was carried out. The results were good, and the amount of triboelectric charge and surface potential measured accordingly were as follows.

Example 13 -9.2 Cog/l 4 -7.8 1LC/g/l
15-29V //16-33V

Claims (4)

[Claims] (1) Guanidines represented by the chemical structural formula below ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R_1 and R_2 are hydrogen atoms, halogen atoms, alkyl groups, aryl groups, aralkyl groups, alkoxy groups,
They represent an aryloxy group, an aralkyloxy group, an alkylthio group, an arylthio group, an aralkylthio group, or a nitro group, and may be the same or different, and the alkyl chain and aryl ring may be substituted. ] A charge-imparting material for developing an electrostatic image, characterized in that it has at least the following on its surface. (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.