JPH07120979A - Electric charge imparting material for development of electrostatic charge image - Google Patents

Abstract

PURPOSE:To increase the extent of triboelectric charge of a toner for developing an electrostatic charge image and to form a clear image having a satisfactory image density, thin line reproducibility and gradation and almost free from fog by using an electric charge imparting material whose performance is not deteriorated even at the time of use over a long period of time. CONSTITUTION:This electric charge imparting material has a compd. represented by the general formula on at least part of the surface. In the formula, each of R<1>-R<3> is H, an alkyl which may have a substituent, a cycloalkyl which may have a substituent or an aralkyl which may have a substituent, R<4> is a halogen or an alkyl and A is a residue of an arom. ring which may have a substituent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material or member having an improved function for imparting an electric charge to a toner used for developing an electrostatic charge image in an electronic copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, a uniform electrostatic charge is applied on a photoconductive insulating layer, and an electrostatic image is formed by irradiating the insulating layer with a light image. Then, the image is developed and visualized with a toner by the technique, a powder image is transferred to paper or the like as required, and then fixed on a copy paper surface by a fixing step. As the toner applied to these, fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin has been used. When a two-component developer is used, the toner is usually used as a mixture with carrier particles such as iron powder. In order to impart an electric charge to the toner, not only the triboelectric charging property of the resin in the toner component is utilized, but also a charge control agent such as a dye or a pigment that enhances the charging property is added. Currently, as charge control agents known in the art, nigrosine dyes, azine dyes, triphenylmethane dyes, quaternary ammonium salts, polymers having quaternary ammonium in the side chain, and the like are known.

[0003]

In order to impart chargeability to the toner, these charge control agents must be exposed to the toner surface to some extent. Therefore, due to friction between the toner particles, collision with the carrier, and the like, the charge control agent falls off from the toner surface, resulting in carrier contamination and the like, resulting in poor chargeability.
Practical problems such as image density reduction, fine line reproducibility reduction, and fog increase occur. The charge control agents capable of imparting the charging property to the toner to the extent that they are practically sufficiently satisfied are very limited, and few are practically used.

The improvement of the charge imparting property to the toner is not achieved only by the charge control agent of the toner, but the carrier, the sleeve, the layer forming blade, etc., which come into contact with the toner during the developing process, are conveyed, regulated, or rubbed. Including these, it is called a "charge-imparting material", and a material or member that contacts the toner prior to or during the development process to impart the charge necessary for the development to the toner, or to supplement the charge. It is also attempted to do so (see JP-A-61-258269). In the method of positively applying the charge-giving material to the toner by using the charge-giving material, the above-mentioned problems can be essentially improved. However, the charge-imparting material such as the carrier, the sleeve, and the layer-forming blade must be durable against friction with the toner and highly durable, and the carrier is particularly desired to be used without being replaced for a long period of time.

[0005]

Therefore, the inventors of the present invention have provided a charge-giving material for imparting an appropriate charge to a toner, and have no deterioration in performance after long-term use, and have fine line reproducibility and gradation. In order to provide a charge-imparting material for obtaining an excellent image, as a result of extensive studies, by using a compound having a specific structure, a charge opposite to the conventional technique, that is, a positive charge is imparted,
The present invention has been achieved by finding that the above-mentioned object can be achieved. That is, the gist of the present invention resides in the general formula (I)

[0006]

[Chemical 2]

[In the formula, R ¹ , R ² and R ³ each have a hydrogen atom, an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a substituent. Represents an optionally substituted aralkyl group, R ⁴ represents a halogen atom or an alkyl group, and A represents an aromatic ring residue which may have a substituent. ] The charge-giving material for developing an electrostatic charge image, which comprises a compound represented by the formula (hereinafter referred to as compound (I)) on at least a part of the surface. Hereinafter, the present invention will be described in detail.

In the above general formula (I), specific examples of R ¹ , R ² and R ³ are hydrogen atom; methyl group, ethyl group, n-propyl group, iso-propyl group, butyl group, pentyl group, Alkyl groups such as hexyl group, heptyl group, octyl group, nonyl group and decyl group; cycloalkyl such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group and cyclodecyl group Group; and aralkyl groups such as benzyl group, phenethyl group and naphthylmethyl group, and the like; hydrogen atom, alkyl group having 1 to 24 carbon atoms, cycloalkyl group having 5 to 8 carbon atoms, and aralkyl having 7 to 12 carbon atoms. Preferred are groups, especially methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group. Group, decyl group, lauryl group,
C1-C1 such as myristyl, cetyl and stearyl groups
Particularly preferred are the 18 alkyl, cyclohexyl and benzyl groups.

The substituent which R ¹ , R ² and R ³ may have is a cycloalkyl group having 5 to 12 carbon atoms;
C2-C18 alkenyl group; hydroxyl group; amino group; mono- or dialkylamino group; alkoxy group such as methoxyl group, ethoxyl group, propoxyl group and butoxyl group; halogen group such as chlorine group, bromine group and fluorine group A heterocyclic residue such as a furyl group and a nitro group are preferred. Specific examples of R ⁴ include halogen groups such as fluorine group, chlorine group and bromine group, and C 1-8 such as methyl group, ethyl group, n-propyl group, iso-propyl group, butyl group and pentyl group. Is preferable, and a chlorine group and an alkyl group having 1 to 4 carbon atoms are particularly preferable. The fourth ammonium ion in the compound (I) is represented by the general formula (II)

[0010]

[Chemical 3]

(Wherein R ⁴ is the same as in the above general formula (I) and R ⁷ represents an alkyl group having 6 to 14 carbon atoms, a cyclohexyl group or a benzyl group) or the general formula (III).

[0012]

[Chemical 4]

An ion represented by the formula (wherein R ⁴ is the same as in the above general formula (I) and R ⁸ represents an alkyl group having 1 to ⁸ carbon atoms) is particularly preferable. R for benzyl group
^The presence of a substituent such as ⁴ reduces the water solubility and facilitates the salt exchange reaction in water. A is an aromatic ring residue which may have a substituent, for example, a phenylene group, a naphthylene group, or an anthrylene group, and a naphthylene group is particularly preferable. As the substituent, an alkyl group, a halogen group,
A hydroxyl group or an amino group is mentioned, and a lower alkyl group or a hydroxyl group is particularly preferable.

Specific examples of compounds (I) that are particularly suitable for inclusion in the charge-imparting material for developing an electrostatic image of the present invention include specific combinations of cations and anions represented by the following structural formulas. However, the present invention is not limited to these. Exemplified compounds (hereinafter, compounds each consisting of a combination of the following cations and anions are referred to as Exemplified compounds (C1) (A1), Exemplified compounds (C1) (A2), ...)

[0015]

[Chemical 5]

[0016]

[Chemical 6]

[0017]

[Chemical 7]

[0018]

[Chemical 8]

[0019]

[Chemical 9]

The compound (I) can be used in the present invention regardless of its production method, and an example of its specific production method will be described below. The compound (I) is generally represented by the general formula (IV)

[0021]

[Chemical 10] (In the formula, R ¹ , R ² , R ³ and R ⁴ are the above general formula (I)
Which has the same meaning as in, X represents halogen) and a quaternary ammonium halide compound represented by the general formula (V)

[0022]

[Chemical 11]

(Wherein A has the same meaning as in the above general formula (I) and Y represents an alkali metal) and the compound is heated in water or alcohol at about 70 ° C. to react. Is obtained by Compound (I)
Although it depends on the form of the charge-providing material to be applied, it is preferable that the charge-providing material is generally provided as particles having an average particle diameter of 10-0.01 μm, and particularly 2-0.1 μm. The compound (I) is applied to the base material of the charge-imparting material by dipping, spraying, brush coating or the like with a coating liquid obtained by dissolving or dispersing it in a solvent or a dispersion medium together with a binder resin, if necessary. Alternatively, when the base material is in the form of carrier particles, the base material is dipped in the coating liquid, mixed and dried, or a method of coating a direct mixture of the base material and the compound (I) with a fluidized bed is used. The charge-imparting material of the present invention can be obtained by forming a coating layer of the compound (I) on the above. Alternatively, the binder resin and the compound (I) may be directly melt-kneaded and extrusion-laminated on the base material to obtain a charge imparting material having a coating layer containing the compound (I). Further, the compound (I) may be contained in a moldable resin, and the compound (I) may be molded into the shape of carrier particles, a sleeve or a layer-forming blade to be used as a charge imparting material.

As the binder resin or the molding resin component, various known ones can be used. For example, there are styrene resins, styrene acrylic copolymer resins, polyester resins, epoxy resins and mixed resins thereof, and those having an amino group in their alkyl side chains. After coating or molding, these resins may have a crosslinked structure, if necessary, to improve the durability of the surface layer of the charge-imparting material. When the binder resin or the molding resin is used, the content of the compound (I) is preferably 0.5-200 parts based on 100 parts of the resin, and particularly 2-100.
Part is particularly preferred.

When the base material is coated, the coating amount must be appropriately controlled, but the compound (I) is 0.01
The range of −10 mg / cm ² is preferable, and 0.1-
2 mg / cm ² is particularly preferred. Further, through the series of cases described above, silica powder, ceramic powder of aluminum oxide, cerium oxide, silicon carbide or the like may be used as a filler together with the compound (I). Further, a conductivity-imparting agent such as carbon black or tin oxide may be used for adjusting the conductivity. Furthermore, in order to prevent the accumulation of spent toner on the sleeve and carrier surface, for example, fatty acid metal salt,
A release agent such as vinylidene fluoride may be used.

All known carriers can be used as the base material of the carrier-type charge-imparting material, and powders of metals or alloys such as iron, nickel, aluminum and copper, or metal compounds containing metal oxides. Alternatively, particles, or ceramic powder or particles of glass, SiC, BaTiO ₂ , or the like is used. In addition, those whose surface is treated with a resin or the like, resin powder, or resin powder containing a magnetic material can be used. The average particle size is preferably about 10 to 200 μm. Further, as the base material of the charge-imparting material in the form of a sleeve or a layer-forming blade, metals or alloys such as iron, aluminum, stainless steel, nickel, etc., non-metallic compounds such as ceramics, plastics, etc. are generally used. What can be used as is can be used.

On the other hand, as the toner to be used in combination with the above-described charge-imparting material of the present invention, substantially the same toners as the conventional electrostatic image developing toners can be effectively used. That is, the toner may be either non-magnetic or magnetic toner. More specifically, it is a colored fine particle in which a colorant is contained in the binder resin, and may contain magnetic powder. Further, these toners may contain a small amount of a charge-imparting substance, for example, a dye, a pigment, or a charge control agent, and a fluidizing agent such as colloidal silica, an abrasive such as cerium oxide or silicon carbide. A lubricant such as metal stearate may be contained. Further, a conductivity imparting agent such as carbon black or tin oxide may be contained.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, "parts" simply means "parts by weight".

Example 1 Methyl ethyl ketone (ME
K) 10 parts of the exemplified compounds (C1) and (A5) in 1 liter of
0 g was dissolved and dispersed, and an iron powder carrier (particle size: 250-
400 mesh) Disperse 1 kg and about 3 in a ball mill.
Stirred for 0 minutes. Dry this iron powder carrier mixture,
After the solvent was completely erased, light agglomeration was loosened to obtain a carrier-like charge-imparting material according to the present invention. Separately, a toner was prepared according to the following formulation.

[0030]

[Table 1] Styrene resin 100 parts (manufactured by Sanyo Chemical Co., Ltd., trade name SBM-600) Carbon black 10 parts (Mitsubishi Chemical Co., Ltd. # 44) Quaternary ammonium salt compound 2 parts (Orient Chemical Co., trade name Bontron) P-51)

The above materials were kneaded, then pulverized and classified to obtain a toner having an average particle diameter of 11 μm. This toner and the carrier-like charge imparting material were mixed at a weight ratio of 4: 100 to obtain a developer. When the triboelectric charge amount of the toner was measured by the blow-off method, it was +32 μC / g. Next, when this developer was actually copied with a commercially available copying machine using an organic photoconductor as a photoconductor, the image density did not change from the initial stage up to 150,000 sheets, fine line reproducibility was good, gradation was also good, and fog also occurred. No clear image was formed.

Comparative Example-1 Exemplified Compound (C1) (A
A developer was prepared in the same manner as in Example 1 except that 5) was not dissolved and dispersed. Triboelectric charge of toner is + 20μC / g
Met. In addition, there was a change in the image density from the initial stage to 150,000 sheets, and the thin line reproducibility and gradation were also lacking. Fog also occurred.

(Example-2) Exemplified compound (C1) (A
A developer was prepared in the same manner as in Example-1, except that the exemplified compounds (C5) and (A6) were used instead of 5). The triboelectric charge amount of the toner was +28 μC / g. In addition, a clear image was formed from the initial stage up to 80,000 sheets.

Example 3 Instead of dissolving and dispersing 100 g of the exemplified compound (C1) (A5) in 1 liter of MEK, 100 g of styrene acrylic resin was dissolved in 1 liter of tetrahydrofuran (THF) to prepare the exemplified compound (C1).
0) A developer was prepared in the same manner as in Example 1 except that 20 g of (A5) was mixed. The toner triboelectric charge is +26
It was μC / g. In addition, a clear image was formed from the initial stage up to 50,000 sheets.

Example 4 Exemplified Compound (C10) (A
A developer was prepared in the same manner as in Example-3, except that the exemplified compounds (C6) and (A6) were used instead of 5). The triboelectric charge amount of the toner was +26 μC / g. Further, a clear image was formed from the initial stage up to 60,000 sheets.

Example 5 A solution was prepared by dissolving 100 g of a styrene acrylate resin in 1 liter of THF and mixing 10 g of the exemplified compounds (C4) and (A5), and applying this solution to a developing sleeve by dipping to form a layer. The thickness was 5 μm. This sleeve was mounted on a commercially available copying machine (magnetic single-component developing system) and a live-copy test was conducted. From the initial stage, clear images were formed on up to 5000 sheets.

Example 6 Exemplified Compound (C4) (A
5) Instead of 10 g, the exemplified compounds (C18) (A5)
A developer was prepared in the same manner as in Example-5 except that 30 g of was used. A clear image was formed from the initial stage up to 4000 sheets.

Example 7 A solution was prepared by dissolving 100 g of styrene acrylate resin in 1 liter of THF and mixing 10 g of Exemplified compounds (C13) and (A8), and spray-coating this solution on a metal blade to form a layer thickness. 20 μm
And This metal blade was mounted as a layer forming blade of a commercially available copying machine (magnetic-component type), and an actual copying test was conducted. A clear image was formed from the initial stage up to 6000 sheets.

(Example-8) Exemplified Compound (C13) (A
8) Instead of 10 g, the exemplified compounds (C11) (A3)
A developer was prepared in the same manner as in Example-7, except that 50 g was used. From the initial stage, clear images were formed on up to 3000 sheets.

[0040]

The charge imparting material for developing an electrostatic charge image of the present invention does not deteriorate in performance even when used for a long period of time, and by using the charge imparting material, the triboelectric charge of the toner for developing an electrostatic charge image is increased. It is possible to form a clear image with improved image density, fine line reproducibility, and gradation and less fog.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Ando 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd.

Claims (4)

[Claims] 1. A compound represented by the general formula (I): [In the formula, R ¹ , R ² and R ³ are each a hydrogen atom, an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a substituent Represents an optionally substituted aralkyl group, R ⁴ represents a halogen atom or an alkyl group, and A represents an aromatic ring residue which may have a substituent]. Charge imparting material for electrostatic image development. 2. The charge-giving material for developing an electrostatic charge image according to claim 1, which is a carrier particle. 3. The charge-giving material for developing an electrostatic charge image according to claim 1, which is a sleeve. 4. The charge-giving material for developing an electrostatic charge image according to claim 1, which is a layer-forming blade.