JPS61259271A - Charge providing material for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a charge providing material capable of attaining the proper electrostatic charging of a toner and having superior durability by holding a metallic complex of benzoylacetone on the surface of a charge providing material such as a carrier for providing electric charges to a toner in an electrophotographic process. CONSTITUTION:A metallic complex of benzoylacetone represented by the formula (where each of R1, R2 and R3 is H, halogen, alkyl, alkoxy, aryloxy, alkylthio, NO2 or the like, R1 and R2 may form a ring which may have a substituent, M is Na, Ni, Al, Pb or the like, X is a neutral ligand selected among H2O, NH3 and ethylenediamine, m=1-3, and n=0, 2 or 4) or the complex and a binder are coated on the surface of a charge providing material such as carrier particles or a doctor blade for providing electric charges to a toner which develops an electrostatic charge image. Thus, an excellent toner image 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 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, and if necessary, the powder image is transferred to paper, etc., and then heated, pressurized, or by solvent vapor, etc. 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 method can be further refined 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 the electrostatic latent image surface.

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

The toner is made by finely pulverizing particles of 1 to 30 IL of a colorant dispersed in a binder resin such as polystyrene.
It is used as 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 method using a so-called two-component developer,
The above toners are 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 toner surface, so these additives fall off from the toner surface due to friction between the toners, collision with the carrier, and friction with the electrostatic latent image carrier. 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 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, contamination sources such as carrier particles and photoreceptors are reduced due to wood quality,
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 benzoylacetone metal represented by the following chemical structural formula. complex (where RI, R2+ R3 are a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, an arylthio group).

represents an aralkylthio group or a nitro group, and these Rs
, R2 and R3 may be the same or different, and R1 and R2 may form a ring, and the ring may have a substituent. M is Na, Li, Zn, C
a, Cu, Co, Cr, Mg.

Mn, Ni, AJI or pb, X is R20
° Indicates a neutral coordination molecule selected from NH3 or ethylenediamine. Grave is an integer from 1 to 3, n is 0. ) representing an integer of 2.4 on at least the surface.

The substituents R,,R2R3 in the structural formula [I] include a hydrogen atom, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, 7 such as optionally branched alkyl groups such as dodecyl group, substituted alkyl groups such as methoxyethyl group, ethoxyethyl group, butoxyethyl group, chloroethyl group, dimethylaminoethyl group, benzyl group, phenethyl group, methylbenzyl group, etc. Alkoxy groups such as ralkyl group, methoxy group, engineered toxy group, propoxy group, butoxy group, octoxy group, 7-aryloxy group such as phenoxy group, methylphenoxy group, butoxyphenoxy group, chlorophenoxy group, benzyloxy group,
Aralkyloxy groups such as methylbenzyloxy group, chlorobenzyloxy group, phenethyloxy group, furkylthio group such as methylthio group, propylthio group, hexylthio group, phenylthio group, methylphenylthio group, ethylphenylthio group, chlorphenylthio group, etc. arylthio group, benzylthio group.

7 such as chlorobenzylthio group, methylbenzylthio group, etc.
Typical substituents include a ralkylthio group and a nitro group.

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

(1) C2) (3
> (4)(s)
(6) These compounds are synthesized by known methods.

For example, compound (1) is produced as follows. When lithium is allowed to act as a cement in ether, an anhydride is obtained, and when the anhydride is recrystallized from water-containing ethyl acetate, a binary product is obtained.

Moreover, compound (2) is produced as follows.

When metallic sodium reacts with benzoylacetone in dry ether, an anhydride is obtained, and recrystallization from water-containing ethanol yields a hydrated product.

The above compound generally has an average particle size of 10 to 0, particularly 2 to 0, although it depends on the form of the charge imparting material to be applied. I
It is preferable to use it as particles of IL to form a charge imparting material.
If it exceeds g, coating becomes difficult and causes inconvenience.

These compounds can be applied by dipping, spraying, brushing, etc. into the base material of the charge-imparting material with a coating solution obtained by dissolving or dispersing them in a solvent or dispersion medium together with a binder resin, or by applying the coating solution to the base material by dipping, spraying, brushing, etc. When the material is in the form of carrier particles, the compound is applied onto 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 compound. The charge imparting material of the present invention can be obtained by forming a coating layer of. 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 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 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 content of the material is preferably in the range of 0.01 to 10 g/crn', preferably 0.1 to 2 mg/cm'.

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. Furthermore, 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, including metals or alloys such as iron, nickel, aluminum, and copper, or powders or particles of metal compounds containing metal oxides, Furthermore, ceramic powder 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 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,
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, the compound of the present invention not only has excellent charge control properties and stability against heat and moisture absorption, but also has the ability to be coated or kneaded onto the surface of a charge-imparting material, as shown in the following examples. 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 l The above compound (
1) was dissolved and dispersed, 1 kg of iron powder carrier (particle size: 25G to 400 mesh) was dispersed therein, and the mixture was stirred in an eel 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 Cabot Corporation) The above materials were mixed, crushed, and classified to have a particle size of 1 to 30 ILm.

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.

Comparison amount -〇, 5 Final C/g When images were produced using a Canon MP-5000 copying machine using these developers, the product of the present invention showed no change in image density even after a durability test of 50,000 sheets. , good fine line reproducibility,
The 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 Xylene 1! ;1 polymethyl methacrylate resin in L
00g was dissolved, and 50g of compound (1) was further mixed therein. This was mixed with the same iron powder carrier as in Example 1,
By drying, a carrier having a charge imparting effect was obtained.

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 -9.1p, C/g, and when an image was produced using this, the obtained image was as follows. Even in a durability test of 50,000 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 (2). A developing sleeve (made of stainless steel) for Canon NP-400RE was dipped in this solution, and the sleeve was coated at 0.1 to 6 rag/crrf.

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 kneading and pulverizing method.

Poly(styrene-butyl methacrylate) 100 parts Wi
w = 300.000 Release agent (trade name PE-130: manufactured by Hoechst) 4 parts Magnetic powder (trade name BL-200: manufactured by Titanium Kogyo Co., Ltd.) 80 parts The prepared toner has a particle size of 1 = ~ 30p. I fainted.

Using this toner, an image printing durability test was conducted using Canon Acid 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 product showed a change in image density after several sheets.

Further, when the surface potential on the sleeve was measured, it was -37V for the product of the present invention (Example 3) and -5V for the comparative product, confirming 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 xylene 1i 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 ML to 30p.

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 41V and was 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 Examples 1 and 2, except that compound (2) used in Examples 3 and 4 was replaced with compound (0). Examples 7 and 8 were carried out in the same manner as in Examples 3 and 4. The results were good, and the correspondingly measured triboelectric charge amount and surface potential were as follows.

Example 5 -4.8 lC/gtt 6 -6.8 lC/gtt 7
-31V//8
-29 V Examples 9 to 12 Compound (1) used in Example 1.2 was converted into compound (
Example 9.10 was carried out in the same manner as in Example 1.2, except that compound (2) used in Examples 3 and 4 was replaced with compound (6). , Examples 11 and 12 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.

Example 9 -8.8pC/g ttl O-7,3gC/g // 11 -41 V // 12 -37 V Examples 13 to 16 Compound (1) used in Examples 1 and 2 was converted to compound (
Example 13.14 was carried out in the same manner as in Example 1.2, except that compound (2) used in Examples 3 and 4 was replaced with compound (8). ,
Examples 15.16 were 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.

Claims (4)

[Claims] (1) A charge-imparting material for developing electrostatic images, which has a metal complex of benzoylacetones represented by the chemical structural formula below (numerical formula, chemical formula, table, etc.) on at least its surface. (In the formula, R_1, R_2, R_3 are a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an alkylthio group,
It represents an arylthio group, an aralkylthio group, or a nitro group, and these R_1, R_2, and R_3 may be the same or different. Further, R_1 and R_2 may form a ring, and the ring may have a substituent. M is Na, L
i, Zn, Ca, Cu, Co, Cr, Mg, Mn, Ni
, Al or Pb, and X represents a neutral coordination molecule selected from H_2O, NH_3 or ethylenediamine. m represents an integer of 1 to 3; n represents an integer of 0, 2, or 4; ) (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.