JPH05257328A - Carrier composition for electrostatic charge image developer - Google Patents

Abstract

PURPOSE:To provide the carrier composition for the electrostatic charge image prevented from attaching to nonimage areas by dispersing or distributing a magnetic material uniformly and stably into the carrier resin. CONSTITUTION:The carrier composition for the electrostatic charge image developer is characterized by containing the magnetic material and a phthalocyanine derivative represented by the formula in which Pc is a phthalocyanine residue optionally substituted by a halogen; A is -CH2-, -CO-, or -CH2NHCOCH2-; R' is H, a lower alkyl, or (-CH2CHR<2>-O-)kH; R<2> is H or methyl; each of k and m is an integer of 1-30; and n is an integer of 1-4.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a carrier composition used for developing an electrostatic latent image by electrophotography, electrostatic recording or the like.

[0002]

2. Description of the Related Art In recent years, electrophotography, electrostatic recording, and electrostatic printing (hereinafter abbreviated as electrophotography) have made remarkable progress.
As described in M. Schaffert, Focal Press, etc.), the surface of the photoconductor is uniformly charged, and then an image corresponding to the original is exposed to eliminate or reduce the charge in the exposed portion. An electrostatic latent image is formed. Next, electrostatic charge developing toner (hereinafter also abbreviated as toner) is electrostatically adhered to the electrostatic latent image to develop the electrostatic latent image so that the electrostatic latent image is visualized. In this case, the amount of adhered toner changes according to the magnitude of the amount of electric charge on the surface of the photoconductor, and as a result, a toner image with light and shade is formed. This toner image is transferred onto a support such as paper, cloth, polymer film, etc. depending on the purpose, and is generally directly or indirectly heated and fixed on the surface of the support.

Many methods are known as a developing method in the electrophotographic method, but when roughly classified, a mixture of a carrier made of fine particles (20 to 400 μm) of iron powder, ferrite, glass and the like and a toner is used as a developer. There are a two-component developing method used as the above and a one-component developing method using a developer consisting of only toner. However, in the one-component developing method, there are problems that the charging property of the toner is likely to be unstable due to the influence of the environment and that highly accurate developing device conditions are required. The two-component developing method is widely used in order to obtain a required high quality image and high reliability.

Typical examples of the two-component developing method are the cascade method described in US Pat. No. 2,618,552 and the magnetic brush method described in US Pat. No. 2,874,063. According to these methods, a relatively stable image can be obtained. However, particularly in the general magnetic brush method, since the allowable range of the mixing ratio of the toner and the carrier in the developing device is narrow, it is difficult to control the mixing ratio, and accordingly, the device for stabilizing the charge amount of the toner should be devised. It was necessary to have it on its own, so the developing device was complicated and easy to be large. In addition, the so-called developer brush (magnetic brush), in which carrier particles are arranged in the direction of the magnetic force line formed by the developer on the developer carrier, is strongly pressed against the surface of the photoconductor due to the strong magnetic force, The life of the developer and photoconductor was shortened. The developer carrying member here is generally a cylindrical one having a plurality of magnetic poles inside. Further, in terms of image quality, the uniformity of the solid image portion was deteriorated by the hard developer ears.

For example, Japanese Patent Publication No. 59-24446 discloses a method of solving the above-mentioned problems by using a so-called resin carrier containing 70 to 90% of magnetic powder in this carrier. That is, the resin carrier has a higher electric resistance than the carrier of iron powder or ferrite due to its composition, and the magnetic binding force is weakened, so that the developer spikes on the developer carrier can be softly brought into contact with the photoreceptor. it can. Further, because of this, the latent image on the photoconductor is uniformly contacted, and the reproducibility of the image is improved. Further, since the particle size can be set arbitrarily, the surface area can be increased, the toner mixing ratio can be increased, the allowable range of the mixing ratio control can be widened, and the developing device can be downsized. Can be simplified and simplified. However, conversely, as a problem caused by the weak magnetic force, there is carrier adhesion to the photoconductor. That is, since the magnetic binding force with the developer carrying member is weaker than that of the carrier such as iron powder or ferrite, the phenomenon that the carrier adheres to the non-image portion of the photoconductor occurs. In particular, when the content of the magnetic material in the carrier is small or the magnetic material is ubiquitous, the phenomenon of carrier adhesion tends to occur, which is a major problem of this developing method.

In order to solve this problem, it is necessary to improve the dispersibility or dispersibility of the magnetic material in the resin, and one of the methods is surface treatment of the magnetic material. That is, in order to improve the wettability and affinity of the magnetic material surface and the resin system to be kneaded, the magnetic material surface is used, for example, a magnetic material which has been subjected to pretreatment such as coating with a coupling agent or a fatty acid, Further, it is to improve the dispersibility by using a surfactant at the time of kneading the magnetic material and the resin. However, in this method, the stability due to environmental changes is poor due to the influence of hydrophilic groups such as carboxyl groups, hydroxyl groups, and sulfonic acid groups at the terminal groups of the surface treatment agent. Was making things worse. In addition, this surface treatment agent is expensive, and the number of steps for surface treatment must be increased, leading to an increase in cost.

[0007]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive studies on the relationship between the structural formula of a compound and the binding / aggregation preventing action of a magnetic material, the present inventors have added a certain compound as a resin carrier composition. By doing so, dispersibility or dispersibility in the resin is improved without adding a pretreatment step such as the above-mentioned surface treatment to the magnetic material, and no carrier is attached to the non-image area. It was found that a resin carrier can be obtained, and the present invention was completed.

An object of the present invention is to provide a carrier for an electrostatic charge image developer, in which a magnetic material in a resin carrier is uniformly and stably dispersed or distributed in a carrier resin, and the carrier does not adhere to a non-image area. It is in.

Another object of the present invention is to provide a resin carrier composition having excellent productivity at low cost.

[0010]

The present invention provides a carrier composition for developing an electrostatic charge image, which comprises a magnetic material and a phthalocyanine derivative represented by the following general formula (1) in a resin. is there. General formula (1)

[Chemical 2] (However, Pc is a phthalocyanine residue which may be substituted with a halogen atom, A is —CH ₂ —, —CO—,
—SO ₂ — or —CH ₂ NHCOCH ₂ —, R ′ is a hydrogen atom, a lower alkyl group, or (—CH ₂ CHR ²
-O-) _k H, R ² is a hydrogen atom or a methyl group, k, m is from 1 to 30 integer, n is an integer of 1-4. )

The binder resin for the resin carrier may be any resin which has been conventionally used as a resin for toner capable of being melt-kneaded, and examples thereof include polystyrene and styrene.
Butadiene copolymers, styrene-based polymers such as styrene-acrylic copolymers and polyethylene, ethylene-vinyl acetate-based copolymers, ethylene-based copolymers such as ethylene-vinyl alcohol-based copolymers and phenolic resins,
A thermoplastic resin such as an epoxy resin or a polyester resin can be used.

As the magnetic material, various ferrites, magnetite, hematite and other iron, zinc, cobalt, nickel, manganese and other alloys or compounds, and various fine metal powders can be used.

The amount of the magnetic material used is 30 to 95% by weight of the carrier weight, and more preferably 45 to 90%.
% By weight. The phthalocyanine derivative having the structural formula shown in the present invention is 0.1 to 20% by weight of the magnetic material used.
Addition improves dispersibility in the resin.
From the economical point of view, the addition amount of 0.1 to 10% by weight is more preferable. The average particle size of the resin carrier is preferably 20 to 400 μm, more preferably 30 to 200 μm in consideration of the influence on the photoreceptor.

The phthalocyanine derivative of the present invention can be synthesized by a known method using phthalocyanine as a raw material. The central metal of the phthalocyanine derivative includes copper, zinc, aluminum, iron, etc., but may be a metal-free phthalocyanine. Specific examples of the phthalocyanine derivative include the following.

[0015]

[Chemical 3]

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

Further, the resin carrier according to the present invention includes:
An internal additive material that imparts the chargeability of the carrier itself may be used.For example, in order to impart a positive chargeability, a nigrosine-based oil-soluble dye, crystal violet, triphenylamine, a quaternary ammonium salt, etc. You may use.
Further, a metal complex salt dye such as a balatin dye or an azole dye may be used in order to impart a negative charging property.

In the method for producing the resin carrier according to the present invention, the above-mentioned carrier constituent materials are hot melt kneaded by using a kneader such as a twin-screw extrusion kneader, a single-screw extrusion kneader, a two-roll mill or a pressure kneader. After that, it is cooled and solidified by roll crusher, disintegrator, screw mill, stamp mill, pin mill, hammer mill, centrifugal classification type mill, ball mill, vibrating ball mill, planetary crusher,
It is crushed using a crusher such as a jet mill, and an airflow classifier,
It is preferable to adjust the particle size distribution to a desired one with a sieve or the like for production.

[0018]

EXAMPLES The carrier according to the present invention will be described below. After thoroughly mixing the materials shown in the respective examples and comparative examples, they were heated and melted at 150 to 170 ° C., kneaded by a twin-screw extrusion kneader, cooled and solidified, and then pulverized by a hammer mill, and then classified by air flow. The particles were classified by a machine to have an average particle size of about 50 μm, and the particle size distribution was made uniform to about 4% of 25 μm or less and about 1% of 80 μm or more to obtain a sample. Thereafter, the toner described below was added to 100 parts by weight of the carrier at a ratio of 10 parts by weight of the toner, and mixed by a rotary mixer for 30 minutes to prepare a developer, and the suitability was evaluated. Further, regarding the suitability evaluation of this sample, a commercially available copying machine (trade name, FP-1300,
It was performed by modifying Matsushita Electric Industrial Co., Ltd.

Example 1 Styrene-acrylic resin (trade name: S-REC P-502, manufactured by Sekisui Chemical Co., Ltd.) 20 parts Styrene-acrylic resin (trade name: Lunaper 912, manufactured by Arakawa Chemical Co., Ltd.) 5 parts Ferrite magnetic material (trade name: PP-7, manufactured by Kanto Denka Kogyo Co., Ltd.) 75 parts Phthalocyanine derivative (the structural formula (a)) 3 parts

Comparative Example 1 The same as Example 1 except that the phthalocyanine derivative was not added.

Example 2 Polyester resin (trade name: Tuffton NE-382, manufactured by Kao Corporation) 25 parts Charge control agent (trade name: Bontron N-02, manufactured by Orient Industry Co., Ltd. 75 parts) Phthalocyanine derivative (the above-mentioned Structural formula (b)) 3 parts

Comparative Example 2 The same as Example 2 except that the phthalocyanine derivative was not added.

Example 3 Styrene-acrylic resin (trade name: S-REC P-502, manufactured by Sekisui Chemical Co., Ltd.) 20 parts Magnetite magnetic material (trade name: EPT-500, manufactured by Toda Kogyo Co., Ltd.) 80 Part Phthalocyanine derivative (the structural formula (c)) 4 parts

Comparative Example 3 The procedure of Example 2 was repeated except that the phthalocyanine derivative was not added.

Example 4 Polyester resin (trade name: NE-382, manufactured by Kao Co., Ltd.) 20 parts Magnetite magnetic material (trade name: EPT-500, manufactured by Toda Kogyo Co., Ltd.) 80 parts Phthalocyanine derivative (described above) Structural formula (d)) 4 parts

Comparative Example 4 The same as Example 2 except that the phthalocyanine derivative was not added.

The following toners were used for the evaluation developers produced in the respective examples. Toner A: Negatively charged magnetic black toner (Matsushita Electric Industrial Co., Ltd.)
Toner B: positively chargeable non-magnetic cyan toner (Toner for FP-C1 manufactured by Matsushita Electric Industrial Co., Ltd.)

Since the toner and the carrier are charged with opposite polarities,
Comparative evaluation with Comparative Example was carried out by using the positively chargeable carrier described in Examples 1 and 2 as the toner A and the toner B as the negatively charged carrier in Examples 3 and 4. The evaluation results are shown in Table-1 and Table-2. The evaluation criteria in the table are represented by ◯: 5 particles or less Δ: 5 to 20 particles ×: 20 particles or more according to the number of carriers attached between image lines. If the number of attached carriers is 5 or less,
There is no problem in practical use.

[0029]

[0030]

[0031]

INDUSTRIAL APPLICABILITY In the present invention, by adding the phthalocyanine derivative as a dispersant to the resin carrier composition, the dispersibility of the magnetic material in the resin is improved, and a resin carrier excellent in magnetic binding force is obtained. Therefore, it is possible to reduce the carrier adhesion to the non-image area, which is seen in the conventional resin carrier. Further, the addition of the phthalocyanine derivative requires less energy to disperse the magnetic material in the resin, and a resin carrier composition having excellent productivity can be provided at low cost.

Claims (1)

[Claims] 1. A magnetic material in a resin and the following general formula (1):
A carrier composition for an electrostatic image developer, comprising a phthalocyanine derivative represented by: General formula (1) (However, Pc is a phthalocyanine residue which may be substituted with a halogen atom, A is —CH ₂ —, —CO—,
—SO ₂ — or —CH ₂ NHCOCH ₂ —, R ′ is a hydrogen atom, a lower alkyl group, or (—CH ₂ CHR ²
-O-) _k H, R ² is a hydrogen atom or a methyl group, k, m is from 1 to 30 integer, n is an integer of 1-4. )