JPS63284565A - Developer for negative charge latent image - Google Patents

Abstract

PURPOSE:To obtain a sharp image having no foggings by incorporating a coated carrier, nonmagnetic toner, positive chargeable fine silica particles and fatty acid metal salt into a titled developer. CONSTITUTION:The positive chargeable fine silica particles subjected to a surface treatment in order to improve the flowability of the developer and to improve moisture resistance by imparting stable and high positive triboelectrostatic charge to the toner are added to the toners. Resistance to flawing is thereby imparted to a photosensitive body and the drop-out of the image and the sweeping seams of the image are greatly eliminated. The fatty acid metal salt is added in addition to the fine silica powder to the toner in order to improve cleanability, to stabilize triboelectrostatic chargeability and to improve the flowability and durability of the developer. The fluctuations in the triboelectrostatic charge are thereby decreased even after long-term use and the durability is improved. The reason for such improvement lies in that the fatty acid metal salt is preferentially adhered onto the carrier particles by addition of the fatty acid metal salt to exhibit the lubricity and to improve the flowability of the developer. Since the thin films are formed on the carrier particles, the adhesion of the other contaminating materials is prevented and the durability is improved.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to the use of electrophotographic methods, electrostatic recording methods, electrostatic printing methods, etc., in which a negative photoreceptor formed on the surface of an organic photoreceptor made of an organic photoconductive semiconductor is used. The present invention relates to a dry developer for developing a latent charge image.

[Background of the invention]

Generally, in electrophotography, a photoreceptor having a photosensitive layer made of a photoconductive material is given a uniform electrostatic charge, and then an electrostatic latent image is formed on the surface of the photoreceptor by performing image exposure. This electrostatic latent image is developed with a developer to form a toner image. The obtained toner image is transferred to a transfer material such as paper and then fixed by heating or pressure to form a copy image.

Selenium photoreceptors, zinc oxide photoreceptors, cadmium sulfide photoreceptors, organic photoreceptors, etc. are known as photoreceptors, but selenium photoreceptors tend to crystallize in high-temperature environments, have poor heat resistance, and have poor sensitivity and other characteristics. The problem is that the image deteriorates and becomes unclear. Furthermore, with zinc oxide photoreceptors and cadmium sulfide photoreceptors, the photosensitive characteristics tend to deteriorate early due to image exposure, resulting in fogging, resulting in unclear images and poor durability, and they are also accused of being toxic to the human body. .

On the other hand, organic photoreceptors made of organic semiconductors do not have the above-mentioned drawbacks, and have advantages such as good film forming properties, low manufacturing costs, high sensitivity, durability, heat resistance, and no toxicity to the human body. It is a preferred photoreceptor.

Generally, a one-component developing method and a two-component developing method are known as methods for developing an electrostatic latent image formed on the surface of a photoreceptor. In the former one-component development method, a one-component developer consisting of a magnetic toner containing a magnetic material etc. dispersed in a binder resin is used, but since it is made of magnetic toner and does not have a carrier, it has poor triboelectric charging properties and is not easily charged. Toner with small or opposite charge coexists,
Developability is unstable and stable images cannot be obtained. Further, it has the disadvantage that toner also adheres to non-image areas on the photoreceptor, causing fog.

In addition, the magnetic substance contained in the magnetic toner is hydrophilic,
Triboelectric charges tend to leak in humid environments. For this reason, in the transfer process, electrostatic transfer to the transfer material deteriorates and the toner transfer rate decreases. As a result, image disturbance occurs on the side where the image density decreases.

On the other hand, the two-component developer used in the latter two-component development method is composed of a toner and a carrier, and the carrier can impart triboelectric charges of appropriate polarity and appropriate amount to the toner. It is possible to impart significantly superior triboelectric charging properties compared to the above-mentioned -component developer. Furthermore, by selecting a carrier having desired characteristics, it becomes possible to control the amount of charge on the toner to a considerable extent, resulting in the stable acquisition of clearer images.

However, when using a two-component developer, there are inherent problems associated with using a two-component developer, such as deterioration of the carrier, deterioration of the photoreceptor and image quality due to carrier scratching on the photoreceptor surface, carrier scattering, and toner scattering. There is a problem.

That is, in a two-component developer, when toner and carrier are stirred and mixed in a developing device to make them homogeneous, mechanical impact force causes
Some of the toner particles are crushed to form toner slag, which accumulates on the surface of the carrier particles, impeding proper frictional charging of the carrier and toner, and causing fogging due to a decrease in the amount of charge on the toner during long-term use. This results in toner scattering due to a decrease in electrostatic adhesion between the toner and carrier, and a decrease in image density and image disturbance due to a decrease in transferability to a transfer material, resulting in a significant decrease in durability.

In addition, when a magnetic brush is formed on a developer carrier using a two-component developer to develop a latent image on a photoconductor, the developer easily scratches the photoconductor and scratches the photoconductor. Due to the scratching, a part of the image is missing (image dropout) or the developed toner image is scratched, resulting in a dark and light striped pattern (sweeping) along the development direction. This phenomenon becomes more pronounced when the fluidity of the developer is poor.

In a two-component developer using a negatively chargeable toner, problems caused by the two-component developer are addressed, for example, by adding negatively chargeable hydrophobic silica fine particles to the toner as described in JP-A No. 45-5782. A method of adding and mixing is adopted. However, when such negatively chargeable silica fine particles are added and mixed into a positively chargeable toner, the positive triboelectric chargeability of the toner is inhibited, resulting in an unclear image with a lot of fog.

In consideration of these circumstances, a method is known in which the surface of silica fine particles, which are originally negatively chargeable, is modified to be positively chargeable by treating the surface thereof, and then added to the toner. For example, Tokuko Sho 5
3-22447 and JP-A-58-185405 disclose inorganic fine particles treated with an aminosilane coupling agent, and JP-A-59-187359 discloses silicic acid fine particles treated with silicone oil having an amine in the side chain. It has been known. By adding and mixing such positively chargeable silica fine particles into toner, clear images with relatively little fogging can be obtained, but a fully satisfactory solution has not yet been reached. Furthermore, all of the problems caused by the interaction with carrier particles described above have not yet been solved.

That is, a charge control agent is usually added to a toner in order to impart desired polarity and triboelectric charge amount. The method of addition is to mix it with a binder resin, melt it, knead it, and disperse it into the toner. However, the charge control agents used as charge control agents are generally dyes and pigments, which are susceptible to thermal decomposition during melting and kneading, deterioration due to temperature and humidity, and are difficult to uniformly disperse in the binder resin, so they do not last long in toner. It is difficult to provide stable charging properties. When a two-component developer is prepared using a toner containing such a charge control agent, the triboelectricity of the toner decreases quickly during long-term use.
This causes fogging and a decrease in image density. Furthermore, when the toner and carrier are stirred in the developer container, crushed toner particles and poorly dispersed charge control agents are liberated, and these liberated substances adhere to the carrier particles, the surface of the photoreceptor, or the developer carrier. Accumulates and contaminates the toner, impairing its triboelectric properties (1
, and also cause deterioration of the characteristics of the photoreceptor, reducing their durability.

Addition of the positively chargeable silica fine particles may be considered as a means to solve the problems caused by such charge control agents, but the improvement is only slight. On the contrary, if the positively chargeable silica fine powder is used, the cleaning effect of the cleaning blade on residual toner on the photoconductor is reduced, and the initial chargeability of the toner and carrier under high temperature and humidity conditions is deteriorated, resulting in poor charging start-up. Therefore, fogging is likely to occur in the initial image.゛Furthermore, the positively charged silica fine particles are released from the toner surface and attached to the carrier particle surface due to the mechanical force received in the developing device, and especially in coated carriers, the positively charged silica fine particles are embedded in the carrier surface. The triboelectric chargeability of the carrier decreases, and the durability of the developer is significantly reduced.

[Purpose of the invention]

The present invention has been made in order to solve the above-mentioned conventional problems as much as possible.

That is, the purpose of the present invention is to provide (1) a developer for developing a negative charge latent image that has high triboelectric chargeability of the toner, is stable, and provides a clear image without fog; (2) has good transferability. A negative charge latent image developer with no image holes and high image density; (3) A negative charge latent image developer with good developer fluidity, which can achieve uniform development and produce images without sweeping marks; 4) Negative charge latent image developer with excellent environmental resistance and stable triboelectric chargeability with good initial rise even under high temperature, high humidity and low temperature and low humidity environmental conditions; (5) crushed toner particle slag (6) Negative charge latent image developer with good durability that avoids contamination of the carrier surface and photoreceptor surface by Our goal is to provide developers.

[Means to achieve the purpose]

The object of the present invention is achieved by a negatively charged latent image developer containing a coated carrier, a nonmagnetic toner, positively charged silica fine particles, and a fatty acid metal salt.

[Actions and effects of the present invention]

According to the developer of the present invention, negative charge latent images can be developed well without sacrificing the advantages of organic photoreceptors.
It is possible to obtain images of good quality, such as high image density without any blemishes, and the durability of operation is good.

In the present invention, surface-treated positively chargeable silica fine particles are added to the toner in order to improve the fluidity of the developer, impart a stable and high positive triboelectric charge to the toner, and improve moisture resistance. . This makes the photoreceptor less likely to be damaged, and it is possible to significantly eliminate image omissions and image sweeps.

In the present invention, in addition to the positively chargeable silica fine particles, a fatty acid metal salt is added to the toner in order to improve cleaning properties, stabilize triboelectric charging properties, improve fluidity of the developer, and provide high durability. By blending the developer in this manner, the developer exhibits even more excellent triboelectric charging properties, and even during long-term use, fluctuations in electrostatic charges are reduced, and durability can be improved. That is, by adding the fatty acid metal salt, the fatty acid metal salt preferentially adheres to the carrier particles, exhibits a lubricating effect, improves the fluidity of the developer, and forms a thin film on the carrier particles. This prevents the adhesion of other contaminants and improves durability.

Furthermore, the fatty acid metal salt adheres to the photoconductor to form a thin layer and exhibits a lubricating effect, reducing the coefficient of friction between the cleaning blade and the photoconductor and preventing cleaning failures due to adhesion of silica particles. In addition to improving cleaning performance, it is possible to prevent toner components and the like from adhering to the photoreceptor, and also to prevent damage to the photoreceptor. Furthermore, since the triboelectric charging efficiency between the toner and the carrier is improved, even under high humidity environmental conditions, the triboelectric charging property is good, and a clear image with high image density can be obtained without fogging.

Further, the present invention is directed to a coated carrier, which helps prevent the adhesion of loose toner scum and particulates added to the toner.

In addition, the developer of the present invention has a coated carrier, a non-magnetic toner, positively charged silica particles, and a fatty acid metal salt as constituent elements, so that the developer has good fluidity and charging stability, and the developer has a magnetic brush. As the abrasion of the photoreceptor due to
Good images that are as good as the initial images can be obtained, and the developer has excellent environmental resistance and durability.

[Specific structure of the invention]

The positively chargeable silica fine particles in the present invention belong to the following categories. That is, 0.2 g of silica fine particles left overnight under the environmental conditions of a temperature of 20 ° C. and a relative humidity of 60% and 19.8 g of uncoated ferrite particles (for example, F-150 manufactured by Nippon Tetsuko Co., Ltd.) were mixed. In the above environment, the amount of triboelectric charge on the silica particles was determined by shaking for 5 minutes in a glass sample container with a volume of about 20 cc, and then using a stainless steel cell with a 635 mesh screen by the usual blow-off method. The result is a positive triboelectric charge.

The positively chargeable silica fine particles have a triboelectric charge of +10 μC/g or more, particularly +30 μC in the above measurement.
/g or more is preferable. When the amount of triboelectric charge is too small, the positive triboelectricity of the non-magnetic toner deteriorates and the amount of triboelectricity decreases, resulting in the occurrence of frizz, or
The durability of the developer may decrease.

The positively chargeable silica fine particles are surface-treated silica fine particles. Examples of substances that can be used for the surface treatment include amino-modified silane coupling agents, amino-modified silicone oils, amino-modified silicone varnishes,
Amino-modified silicone compounds such as amino-modified silicone rubber, amino-modified silicone resin, or cured products thereof can be preferably used. Amino-modified silicone varnishes, amino-modified silicone rubbers, amino-modified silicone resins, or cured products thereof are preferred because they provide particularly excellent positive chargeability, moisture resistance, and durability. According to the silica fine particles surface-treated with such an amino-modified silicone compound, the presence of amino groups results in silica fine particles with excellent positive chargeability, and moreover, the functional groups of the silicone compound and the surface of the silica fine particles Since the existing hydrophilic groups such as hydroxyl groups are strongly bonded, the silica fine particles have excellent moisture resistance and durability, and have stable positive triboelectric charging properties that are not affected by environmental conditions.

As the amino-modified silicone varnish preferably used to obtain positively chargeable silica fine particles, for example, amino-modified methyl silicone varnish, amino-modified phenylmethyl silicone varnish, amino-modified phenyl silicone varnish, etc. can be used, and in particular, amino-modified Methyl silicone varnishes are preferred. Such an amino-modified silicone varnish has a T unit, a D'' unit, an M1' unit, and a part of the organic group present in each of these units has been substituted with a group having an amine 7 group as shown in the following structural formula. It is a three-dimensional polymer comprising 10 to 90 mol%, preferably 30 to 80 mol% of T'' units. If the proportion of the T'1 units is too small, the stability of triboelectric charging may decrease due to tackiness, and the carrier may be contaminated, resulting in a decrease in the durability of the developer.On the other hand, the T'1 When the ratio of units is too large, the cleaning blade becomes easily damaged due to excessive hardness, and as a result, cleaning failures are more likely to occur.

It's the office! □ [Tl1 unit: l CD l + unit]
ll [M1111 single R low Si -0- K... In each unit Rl l, Rl 2, R13, R
I 4 , )j 15 and R tsuta 6 each do not represent an alkyl group such as a methyl group or an ethyl group, an aromatic group such as a phenyl group, or an organic group such as a polyether group, a hydroxyl group, or an amino group.

Specifically, it is a substance having a chemical structure as shown by the following structural formula (1), for example.

Structural formula (1) %Formula% Here, Rl71R'' represents an organic group such as a methyl group or a phenyl group.

The amino-modified silicone rubber preferably used to obtain positively chargeable silica particles includes, for example, I) 21 units represented by the following structural formula, and some of the organic groups present in the units have amine 7 groups. It is a long chain polymer consisting of units substituted with groups.

-ゝ＼ [D2121 unit [:1) 22 units] R” R” In each unit, R21, R22, R23 are an alkyl group such as a methyl group or an ethyl group, an aromatic group such as a phenyl group, a polyether group, Represents a hydroxyl group, an amine group, etc.

Further, in order to make the silicone rubber have a crosslinked structure, it is preferable to copolymerize using a single amount of D2222 represented by the above structural formula.

The amino-modified silica resin preferably used to obtain positively chargeable silica particles includes the T1' unit, the D
1111 A polymer consisting of a single M'' unit and a unit in which a part of the organic group present in each of these units is substituted with a group having an amino group, and unlike silicone oil, it contains a large amount of T'' units. It is.

In the amino-modified silicone varnish, especially T”
The unit imparts good thermosetting properties, and furthermore, the T
It has a three-dimensional network structure with 11 units, and in amino-modified silicone rubber, it has a cross-linked structure especially from D2222 units, and in amino-modified silicone resin,
The Tll unit has many branches, resulting in a cross-linked structure, and a cyclic structure is formed within the molecule. As a result, the silica particles having the above-mentioned silicone compound on the surface form a tough coating on the surface, and have high impact resistance and
It has excellent moisture resistance and mold releasability.

In addition, amino-modified silicone varnishes, amino-modified silicone rubbers, and amino-modified silicone resins contain a considerable amount of silanol groups that do not form siloxane bonds and have OH groups, so these silanol groups are present on the surface of the silica particles. It reacts with functional groups such as dehydration condensation, or forms siloxane bonds during the curing stage.
As a result, the coating has stronger properties.

In addition, in the case of amino-modified silicone varnish, examples of curing accelerators that can be used to accelerate the curing reaction include fatty acid salts such as zinc, lead, cobalt, and tin;
Amines such as triethanolamine and butylamine 7;
etc. can be used. Among these, amines can be particularly preferably used. In addition, in the case of amino-modified silicone rubber, known vulcanizing agents can be used, such as 1r benzoyl peroxide, bis-
Organic peroxides such as 2,4-dichlorobenzoyl peroxide, di-butyl peroxide, and tsucumyl peroxide are preferably used.

In addition, as the group having 7 amino groups in the amino-modified silicone rubber, amino-modified silicone rubber, and amino-modified silicone resin, those represented by, for example, the following structural formula are preferable.

-CH2CH2-NH2 -CH2(CH2)2-NH2 -CH2(CH2)2-NH-(CH2), -NH2Amino/modified silane coupling agents used to obtain positively chargeable silica particles include, for example, the following: Compounds represented by the chemical formula are preferred.

H2N CH2CH2CH2S i (OCH3)3
H3 H2N CH-C! (2CH2S i (OC2H,)
2H3 H2NCH2CH2CH25i (OCH3) 2H3 H2N CH2CH2N HCH2CH2CH2S +
(OCH3)2H2N CH2CH2N HCH2C
H2CH2S + (OCH3)3-CH2CH2Si
(OCHz)z H5C20COCH2CH2NHCH2CH2CH2-
-3i(OCH3)3 (HsC2)2NCHzCH2CH2Si(OCHz)
Furthermore, as the amino-modified silicone oil, for example, one represented by the following general formula (A) can be used.

General formula (A) where R41 represents an alkylene group, 7-aryl group, aminoalkylene group, etc., R42 and R'3 each represent a hydrogen atom, a hydroxyl group, an alkyl group, an aryl group, etc., and x, y each represents an integer of 1 or more.

Further, as the amino-modified silicone oil, one having an amine 7 equivalent value within the range of 300 to 000 is preferable. If the value of the amine 7 equivalent is too small, the effect of imparting positive chargeability by the silica particles will be small, resulting in a foggy and unclear image. On the other hand, if the value of the amine 7 equivalent is too large, Silica fine particles tend to transfer and adhere to carrier particles, which may reduce the durability of the image forming agent.

Examples of commercially available Ami-7 modified silicone oils that can be preferably used include those listed in Table 1 below.

The primary particles of silica fine particles (particles separated into individual unit particles) whose surface is treated with the above-mentioned compound are:
It is preferable that the average particle size is within the range of 3 mμ to 2 μm.

Such silica fine particles are fine particles having a Si-〇-5i bond, and may be produced by either a dry method or a wet method, but they have the advantage of providing good developer fluidity and moisture resistance. Silica particles produced by a dry method are preferred, and silica fine particles produced by vapor phase oxidation of a silicon halogen compound are particularly preferred. Further, as the silica fine particles, in addition to silicon dioxide (silica), fine particles made of silicates such as aluminum silicate, thorium silicate, calcium silicate, potassium silicate, zinc silicate, and magnesium silicate may be used. Those containing at least % by weight are preferred.

As a method for treating the surface of silica fine particles with the above compounds, known techniques can be used. Specifically, for example, using a fluidization bed device, a solution of the above compound components dissolved in a solvent can be used. A method may be used in which the coating is spray-coated onto fine silica particles and then heated and dried to remove the solvent and cure the coating.

Hereinafter, in the lower margin, the particle size of the positively chargeable silica fine particles surface-treated (coated) with the above-mentioned compound is such that the average particle size of the primary particles is 3 mμ to 2 μm, particularly 5 mμ to 500 mμ.
It is preferably within the range of μ. Also, BET
The specific surface area determined by the method is preferably 20 to 500 i2/g. If the average particle diameter is too small or the specific surface area is too large, the silica particles may easily slip through during cleaning using a blade-type cleaning device, resulting in poor cleaning. On the other hand, when the average particle size is too large or the specific surface area is too small, the fluidity of the developer decreases, resulting in poor developability, which may result in a decrease in image density or the occurrence of streaks in the image.

The silica powder consisting of the positively charged silica particles is added to and mixed with the non-magnetic toner powder, thereby being attached and retained on the surface of the non-magnetic toner particles.

The content of the positively chargeable silica fine particles is preferably 0.1 to 5% by weight, particularly 0.1 to 5% by weight of the nonmagnetic toner.
Preferably it is 2% by weight. When the content of positively chargeable silica fine particles is too small, the fluidity of the developer may decrease, resulting in poor triboelectric charging properties of the nonmagnetic toner, and the nonmagnetic toner does not have an appropriate amount of positive charge. It becomes difficult to apply the image, and fogging and sweeping lines may occur in the image. In addition, when the content ratio is excessive, some of the positively charged silica particles may exist in a free state from the non-magnetic toner particles, and as a result, the free positively charged silica particles may adhere to and transfer to the carrier particles. Or, it adheres and accumulates on the developer carrier, regulating blade, etc., and eventually the triboelectric charging properties of the non-magnetic toner become poor, making it difficult to apply an appropriate amount of positive charge, or 1? ') or a decrease in image density may occur.

The fatty acid metal salt used in the present invention is preferably a metal salt of a saturated or unsaturated fatty acid having 8 to 35 carbon atoms. Examples of the above-mentioned fatty acids include stearic acid, palmitic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, tridecanoic acid, pentadecanoic acid, mystylic acid, cerotic acid, etc., and examples of the metal salts include lithium, Sodium, potassium, copper, magnesium, calcium, zinc, strontium, barium,
aluminum, tin, titanium, zirconium, nickel,
Examples include salts of cobalt, iron, and the like.

In particular, metal stearates such as zinc stearate are preferred in terms of obtaining good durability and image quality.

The fatty acid metal salt is attached and retained on the surface of the non-magnetic toner particles by being mixed as a powder with the non-magnetic toner particles.

The content ratio of the fatty acid metal salt is 0.01 in the non-magnetic toner.
It is preferably from 5% by weight, particularly preferably from 0.05 to 2% by weight. When the content of the fatty acid metal salt is too low, the fluidity of the developer may decrease, resulting in poor triboelectric charging properties of the non-magnetic toner and imparting an appropriate amount of positive charge to the non-magnetic toner. This makes it difficult to do both, and fogging and sweeping lines in the image may occur.

In addition, when the content ratio is excessive, a part of the fatty acid metal salt may exist in a free state from the non-magnetic toner particles, and as a result, the free fatty acid metal salt may adhere to and transfer to the carrier particles, or may be transferred during development. It adheres and accumulates on the agent carrier, regulating blade, etc., and as a result, the triboelectric charging properties of the non-magnetic toner become poor at an early stage, making it difficult to apply an appropriate amount of positive charge to the non-magnetic toner (R+) or a decrease in image density may occur.

The non-magnetic toner constituting the negative charge latent image developer of the present invention is
Basically, they are particles that contain colorants and other additives in a binder resin, and their average particle size is 5 to 5.
Preferably, it is 20 μm.

Other additives that can be used include, for example, fixability improvers, charge control agents, and the like.

The binding resin constituting the non-magnetic toner is not particularly limited, and various resins may be used.

Specifically, for example, polystyrene resin, styrene-acrylic copolymer, poly-styrene-butadiene resin,
Polyester resin, epoxy resin, polyamide resin, polyurethane resin, etc. can be used. In particular, styrene-acrylic copolymers can be preferably used, and among them, copolymers obtained by polymerizing styrene monomers with acrylic acid or its ester and/or metal acrylic acid or its ester are preferably used. be able to.

In the styrene-acrylic copolymer, the styrene component is preferably contained in an amount of 95 to 60% by weight of the copolymer. If the proportion of the styrene component is too large, the copolymer may become brittle and the durability of the non-magnetic toner may be reduced. On the other hand, if the proportion of the styrene component is too small, the copolymer tends to transfer and adhere to the wall of the developing device, and as a result, the triboelectric charging properties of the nonmagnetic toner may be inhibited.

Below (・□i' mark i, ,,,,,;/ Specific examples of styrene monomers that can be used to obtain the styrene-acrylic copolymer include styrene, 0-methyl, etc. Styrene, l-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-t-butylstyrene, p-n-hexylstyrene , p-n-octylstyrene, p-n-7nylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlor Examples include styrene, etc. These monomers may be used alone or in combination.

Furthermore, examples of the acrylic component that can be used to obtain the styrene-acrylic copolymer include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl a-chloroacrylate, methacrylic acid, methyl methacrylate, methacrylic acid Ethyl, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, 7enyl methacrylate, dimethylaminoethyl methacrylate, Examples include a-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate; acrylic acid or methacrylic acid derivatives; and others.

These monomers may be used alone or in combination.

As a method for producing the styrene-acrylic copolymer, for example, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, etc. can be used.

Examples of colorants include carbon black, 7-talocyanine blue, benzidine yellow, nigrosine dye, aniline blue, carfoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, malachite green offsalate, lamp. Dyes and pigments such as black and rose bengal can be used. These substances may be used alone or in combination, and the content of the colorant is usually preferably 1 to 15% by weight of the nonmagnetic toner.

As the fixing property improver, for example, polyolefins, fatty acid esters, fatty acid ester waxes, solid paraffin waxes, amide waxes, silicone varnishes, aliphatic 70 carbons, and the like can be used.

As the charge control agent, for example, nigrosine dyes, metal complex dyes, ammonium salt compounds, aminotriphenylmethane dyes, polymers having 7 amino groups such as styrene-dimethylaminoethyl methacrylate copolymer, etc. may be used. Can be done.

As the coated carrier constituting the developer used in the present invention, carriers having various configurations can be used. Specifically, a coated carrier in which the surface of magnetic particles is treated with a silicone compound or a fluorine resin is preferred.
Compounds used in the coated carrier include silicone compounds such as silane coupling agents, silicone oils, silicone varnishes, silicone rubbers, silicone resins, and cured products thereof; for example, vinylidene fluoride-ethylene tetrafluoride copolymers. , tetrafluoroethylene,
Use of fluorine-based resins such as methyl methacrylate-methacrylic acid-i, 1-dihydroxyperfluoroethyl copolymer, styrene-methacrylic acid-1,1,3-)rihydroxyperfluoro-propyl copolymer; is preferred. The above-mentioned substances may be used alone or in an appropriate combination of multiple types.

Among these substances, silicone compounds are particularly preferably used because they provide excellent developability and chargeability, and among them, silicone varnishes, silicone rubbers, silicone resins, or cured products thereof are particularly preferably used. can. In coated carriers obtained using such silicone compounds, the surface energy is considerably reduced, and as a result, transfer and adhesion of toner substances or positively charged silica particles to carrier particles occur, resulting in contamination of the carrier. This can be considerably suppressed, making it possible to obtain a developer with excellent durability.

Further, as the silicone varnish, silicone rubber, and silicone resin, those having an organic group such as an alkyl group or an aromatic group as a constituent unit are preferable, and those having an organic group such as a methyl group or a phenyl group are particularly preferable. Specific examples of silicone compounds having such organic groups include dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, and modified products thereof. In particular, polysiloxane having a methyl group or phenyl group has excellent negative charging properties, and when a coated carrier obtained using the polysiloxane and a non-magnetic toner are frictionally charged, the non-magnetic toner has a good positive charge. A triboelectric charge can be applied. By appropriately selecting the content ratio of methyl groups and phenyl groups among the above organic groups, it is possible to adjust the properties of the carrier coating, such as hardness, toughness, and triboelectric charging properties. There is an advantage that the conditions required for the non-magnetic toner used in combination are considerably relaxed, and the range of non-magnetic toners to be selected is wide.

Commercially available silicone varnishes include, for example, [5
R2101J, 1sH997J, [5H994J, [5
R2202J, [5E9140JrsH643J, [5
) 12047J, [JcR6100J, “JcR610
1J (manufactured by Toray Silicone), JKR27
1J, [KR272J, 1-KR274J, [KR21
6J, [KR280J, 1KR282J, "KR261
J, [KR260J, "KR255J," KR266J
, [KR251J, l"KR155J, [KR152J
, rKR214J, IKR220J, [X -40-1
71J, 1KR201J, "S^-4", "KR520
2J, l''KR3093J, rEcloolJ (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

Commercially available silicone rubbers include, for example, [5]
1410J, "5H432J, [5H433J, l'-
5H740J, [SH3511J, [511751J
J, s+1841UJ, ('5t(1125[IJ,
[S old 603tlJ, [S H665UJ, [5E95
5UJ, JSH502υ], rsRX-440UJ (
(manufactured by Toray Silicone), etc.

Further, when forming a coated carrier using the silicone compound as described above, a curing agent may be used as necessary. Examples of such curing agents include peroxides such as benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, ditertiary-butyl peroxide, and tertiary-butyl perbenzoate; octylic acid, naphthenic acid, etc. metal soaps such as lead, iron, cobalt, manganese, and zinc; organic amines such as ethylamine; and the like.

The magnetic particles constituting the carrier include materials that are strongly magnetized in the direction of a magnetic field, such as iron, ferrite,
Particles made of ferromagnetic metals or alloys such as magnetite, iron, nickel, and cobalt, or compounds containing these elements can be used, and ferrite particles, which do not cause carrier scattering, are particularly preferred.

The method for producing the coated carrier is not particularly limited, but for example, a coating solution prepared by dissolving the coating components and a curing agent used as necessary in a solvent is applied to the surface of the magnetic particles, and then heated. Dry to remove the solvent by volatilization,
It can be manufactured by thermally curing the coating layer, if necessary.

The coating method is not particularly limited, but includes, for example, a dipping method in which powder of magnetic particles is immersed in a coating solution, a spray method in which the coating solution is sprayed onto the magnetic particles, and a method in which the magnetic particles are suspended using fluidized air. A fluidized bed method or the like can be used in which a coating liquid is sprayed onto the magnetic particles in the state.

As the solvent for the coating liquid, for example, toluene, xylene, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, higher alcohol, or a mixed solvent thereof can be used.

The average particle diameter of the carrier is preferably 5 to 500 μm, particularly preferably 20 to 200 μm.

When the average particle size of the carrier is too small, a so-called carrier adhesion phenomenon occurs in which the carrier adheres to the electrostatic latent image and forms a fixed image, and as a result, the image may become unclear. When is excessive, image unevenness may occur. Note that the average particle diameter (weight) of the carrier is a value measured using "Microtrack" (manufactured by Nikkiso Co., Ltd.).

The organic photoreceptor according to the present invention is constructed by laminating a photosensitive layer in which a photoconductive semiconductor made of an organic compound is dispersed in a resin binder on a conductive support made of, for example, aluminum or stainless steel.

The photosensitive layer may be a carrier-generating substance that absorbs visible light and generates charge carriers, such as an anthurone compound, perylene derivative, bisazo compound, or phthalocyanine compound, or a styrene-methyl methacrylate copolymer, polycarbonate, or the like. ) A carrier generation layer dispersed in a binding resin such as tlH fat or silicone resin, and a carrier such as an oxadiazole derivative, a triarylamine derivative, a polyarylalkane derivative, a hydrazone derivative, a stilbene derivative, a styryltriarylamine derivative, etc. It is preferable to use a functionally separated photosensitive layer formed by combining a carrier transport layer containing a carrier transport substance that transports carriers generated in the generation layer.

〔Example〕

Hereinafter, specific examples and comparative examples of the present invention will be described, but the present invention is not limited to these examples.

(Manufacture of silica fine particles) (1) Silica fine particles Al (Example) have the following D1 unit, the following T1 unit, and the following T1 unit as constituent units,
The molar ratio of these is 4 = 1:5 and Of(
25 °C in a xylene solution with a concentration of 30% by weight
A treatment solution was prepared by dissolving a sulfur solution manufactured by Amino Modified Silicone Co., Ltd. having a viscosity of 50 to 200 cps in xylene.

Margin below (1) 1 unit] [TI unit] [Go to D
1 unit] Next, silica fine particles "Aerosil 200" (manufactured by Nippon Aerosil Co., Ltd.) were placed in a mixer, and the amino-modified silicone varnish was sprayed at a ratio of 20% by weight to the silica fine particles. was placed in a flask, and while stirring at a temperature of 200° C. for 5 hours, the solvent xylene was removed and the amino-modified silicone varnish was subjected to a curing reaction, thereby obtaining surface-treated positively chargeable silica fine particles. This is [Silica fine particles AI]
Let it be J.

The silica fine particles A1 have an average particle size of primary particles of 12
mμ, and the specific surface area measured by the BET method is 110 m2/g.

Further, the amount of triboelectrification with non-coated ferrite particles "F-1504 (manufactured by Nippon Tetsuko Co., Ltd.) is +72 μC/g.

(2) Silica fine particles A2 (Example) have the above D1 unit, the following D2 unit, and the following formula D2 unit as constituent units, the molar ratio of these is 5:2:3, and the viscosity at 25°C is 6X An Ami-7 modified silicone rubber having an average molecular weight of 10'cps and 7×10G and 2% by weight of benzoyl peroxide based on the 7-minomodified silicone rubber were dissolved in xylene to prepare a treatment solution.

[D2 unit] CI+3 -Q-Si-0- CH= C12 [^D2 unit] Hi -0-Si-0- CB2(CH2)2NH(CH,)3NH2 Next, silica fine particles "Aerosil 300J (Japan Aeronol Co., Ltd.) ) was placed in a mixer, and the silica particles were sprayed with a treatment solution such that the amino-modified silicone rubber accounted for 10% by weight, followed by surface treatment in the same manner as in the production of silica particles A1. Positively charged silica fine particles were obtained.These are referred to as "silica fine particles A2." The silica fine particles A2 have an average primary particle diameter of 7 mμ, BET
The specific surface area by method is 1.45m27g. Further, the amount of triboelectrification with uncoated ferrite particles [F-1504 (manufactured by Nippon Tetsuko Co., Ltd.) is +162 μC/g.

(3) Silica fine particles A3 (Example) have the above D' unit, the above D2 unit, the following ^D3 unit, and the above T' unit as constituent units, and the molar ratio of these is 4.5: 1,5
: 2 : 2: Amino/modified silicone resin and 0.5% by weight based on this amino modified silicone resin
A treatment solution was prepared by dissolving benzoyl peroxide in xylene.

[To D3 units] CH3? Next, silica fine particles [Aerosil 200J (Nippon Aerosil Co., Ltd. g1) were placed in a □ mixer, and a treatment liquid was sprayed onto the silica fine particles in a proportion such that the ami7-modified silicone resin was 30% by weight. , surface-treated positively chargeable silica fine particles were obtained in the same manner as in the production of silica fine particles A1. This is [Silica fine particles A3J
shall be. The silica fine particles A3 have an average primary particle diameter of 12 mμ and a specific surface area of 8211+2/
It is g. In addition, “uncoated ferrite particles IF-t5o”
(manufactured by Nippon Tetsuko Co., Ltd.) and the amount of frictional electrification is +81 μC/g.

(4) Silica fine particles A4 (Example) Silica fine particles [
Aerosil 200J (manufactured by Nippon Aeronol Co., Ltd.) 100
A solution of amino-modified silicone oil dissolved in isopropyl alcohol (viscosity (25°C)) was added to the silica fine particles in a closed-type Henschel mixer heated to
= 1200 cps, Amide 7 equivalent = 3500) was stirred at high speed while spraying at a rate such that the treated amount of Amide/modified silicone oil was 2.0% by weight, and then dried at a temperature of 150 ° C. Positively chargeable silica fine particles surface-treated by the above method were obtained. This is [Silica fine particles A
4J. The silica fine particles A4 have an average primary particle diameter of 12 mμ and a specific surface area of 12011 by BET method.
12/ [? It is. In addition, uncoated ferrite particles [F-
The amount of frictional charge with 150J (manufactured by Nippon Tetsuko Co., Ltd.) is +110μ
C/g.

(5) Silica fine particles A5 (Example) Silica fine particles [Aerosil 300j (manufactured by Nippon Aerosil Co., Ltd.) were placed in a closed Henschel mixer heated to 70°C, and the silica fine particles were mixed with an Ami7-modified silane coupling agent. A solution of a certain γ-7 minobrobyltriethoxysilane dissolved in alcohol was stirred at high speed while being sprayed at a rate such that the amount of the amino-modified silane coupling agent treated was 5.0% by weight, and then temperature 1
It was dried at 20'C, thereby obtaining surface-treated positively chargeable silica fine particles. This is [Silica fine particles Ajl
shall be.

The silica fine particles A5 have an average primary particle diameter of 8 mμ.
, the specific surface area by BET method is 151 m2/g.

Further, the amount of frictional electrification with uncoated ferrite particles rF-150J (manufactured by Nippon Tetsuko Co., Ltd.) is +94 μC/g.

(6) Silica fine particles A6 (comparative example) Negatively chargeable silica particles rR-972J (manufactured by Nippon Aerosil Co., Ltd.) were used as silica fine particles A6. The silica fine particles A6 have a frictional charge amount of 1200 μC/g with the uncoated ferrite particles rF-150J (manufactured by Nippon Tetsuko Co., Ltd.).

(fatty acid metal salt) (1) Fatty acid metal salt B1 "Zinc stearate" (manufactured by Kanto Kagaku Co., Ltd.) is designated as B1.

(2) Fatty acid metal salt B2 "Copper stearate" (manufactured by Kanto Kagaku Co., Ltd.) is designated as B2.

(Manufacture of carrier) (1) 8 parts by weight of carrier C1 silicone varnish rSR-2101J (manufactured by Torre Silicone) was added using a fluidized bed device.
10 of spherical copper-zinc ferrite particles (manufactured by Nippon Tetsuko Co., Ltd.)
0 parts by weight was spray coated and further heat treated at 200° C. for 5 hours to sinter, and then the aggregates were sieved to produce a carrier having a coating layer made of sintered silicone varnish. This will be referred to as "carrier C1."

This carrier C1 has an average particle size of 102 μm.

(2) Carrier C2 In manufacturing carrier C1, silicone rubber rsll
-2047J (manufactured by Le Silicone Co., Ltd.), 0.05 parts by weight of benzoyl peroxide, and 100 parts by weight of spherical copper-zinc ferrite particles (manufactured by Nippon Tetsuko Co., Ltd.) were used. A carrier having a coating layer made of a sintered product of silicone rubber was manufactured in the same manner. This is called [carrier C2J]. This carrier C2 has an average particle size of 81 μm.

(3) Carrier C3 Spherical copper-zinc ferrite particles (manufactured by Nippon Tetsuko Co., Ltd.) were added to a coating solution prepared by dissolving 2 parts by weight of silicone resin rsR-2400J (manufactured by Le Silicone Co., Ltd.) in 50 parts by weight of xylene. ) 100 parts by weight was immersed, heated to volatilize and remove the solvent xylene, further heat-treated at 200°C for 5 hours and sintered, and then the aggregates were sieved and separated from the sintered silicone resin. A carrier having a coating layer was manufactured.

This is referred to as carrier C3J. This carrier C3 has an average particle size of 60 μI.

(4) Carrier C4 A coating liquid was prepared by dissolving 158 of the above polymer in 500 ml of a mixed solvent of acetone and methyl ethyl ketone (mixed volume ratio -1:1), and this coating liquid was mixed using a fluidized bed apparatus. Then, 1 kg of magnetic particles made of spherical copper-zinc ferrite particles were coated and further heated at 200°C for 5 minutes.
After heat treatment for a period of time, the agglomerate was then sieved to produce a carrier with a coating layer. Let's call this "Carrier C4J."

This carrier C4 has an average particle size of 80 μm.

(5) Carrier C5 Styrene-methylethacrylate-1 copolymer (monomer composition ratio -30:70) 15g of methyl ethyl ketone 3
Prepare a coating solution by dissolving it in
The above-mentioned coating liquid was applied onto 1 kg of spherical copper-zinc ferrite particles using a coating solution (manufactured by Kaida Seiko Co., Ltd.), and then heated and dried to produce a carrier having a coating layer. This will be referred to as "Carrier C5." This carrier C5 has an average particle size of 110 μm.

(Production of non-magnetic 1 to toner) (1) Toner T1 Poly-styrene-n-butyl acrylate-1 copolymer (
Monomer composition ratio -82.18) 100 parts by weight, carbon black [Mocal LJ (manufactured by Cabo Soto)
After mixing 10 parts by weight and 2 parts by weight of "Nigrosine SO" (manufactured by Orient Chemical Industry Co., Ltd.) using a ■-type flender,
Melt kneading is performed using two rolls, then cooled, coarsely pulverized using a hammer mill, further finely pulverized using a jet mill, and then classified using an air classifier to obtain an average particle size of 11.
A non-magnetic toner of 0 μ[n was obtained. Let this -l fu- be [toner TIJ].

(2) Toner T2 In the production of toner T1, styrene-n-butyl acrylate-methyl methacrylate copolymer (monomer composition ratio = 70:20:10) 100 instead of styrene-n-butyl acrylate copolymer. A nonmagnetic toner having an average particle size of 10.5 μm was obtained in the same manner except that parts by weight were used. This is called ``Toner T2J.''

(3) Toner T3 In the production of toner T1, styrene-n-butyl methacrylate copolymer (monomer composition ratio -65:35) was used instead of styrene-n-butyl acrylate copolymer.
In the same manner except that 100 parts by weight was used, the average particle size was 1.
A non-magnetic toner with a diameter of 1.3 μm was obtained. This [Toner T
3J.

(Preparation of developer) A developer was prepared in the following manner using carrier, toner, silica fine particles, and fatty acid metal salt in combinations and amounts shown in Table 2 below.

First, silica particles are added to the toner,
By mixing these with a Henschel mixer,
A developer was prepared by depositing silica fine particles on the surface of toner particles, followed by depositing a fatty acid metal salt in the same manner, and then mixing these with a carrier.

(Organic latent image carrier) (1) Organic latent image carrier P1 A photosensitive layer with a negatively charged two-layer structure formed using an anthurone pigment as a carrier generating substance and a carbazole derivative as a carrier transporting substance, An organic latent image carrier was constructed by laminating it on a rotating drum-shaped aluminum conductive support. This is referred to as "organic latent image carrier PIJ."

(2) Organic latent image carrier P2 An organic latent image carrier was constructed in the same manner as organic latent image carrier P1, except that a bisazo pigment was used as the carrier generating substance and a hydrazone derivative was used as the carrier transporting substance. This is referred to as [organic latent image carrier P2J].

(3) Organic latent image carrier P3 An organic latent image was produced in the same manner as organic latent image carrier P1 except that a bisazo pigment was used as the carrier generating substance and a styryl triarylamine derivative was used as the carrier transport substance. A carrier was constructed. This is referred to as "organic latent image carrier P3."

Below is the bottom margin <Live-action test> (1) Test 1 (Live-action test under room temperature environmental conditions)
g) An electronic device comprising an organic latent image carrier for forming a negatively charged latent image, a magnetic brush developing device, a corona transfer device for generating corona discharge, and a cleaning device having a cleaning blade made of urethane rubber. Photocopy machine "U-B"
Using a modified machine of ix1550MRJ (manufactured by Konishi Roku Photo Industry Co., Ltd.), a live-action test was conducted to form an image on an organic latent image carrier at 80,000 cm under room temperature environmental conditions of 20°C and 50% relative humidity. Each of the following items was evaluated.

In each Example and Comparative Example, the developer used is as shown in Table 2 above.

In addition, in the above-mentioned live-action test, other developing conditions were as follows. That is, the surface potential (highest potential) of the organic latent image carrier during charging is -500V, the magnet roll is a rotating type, the magnetic flux density on the surface of the developing sleeve is 800 Gauss, and the moving direction of the organic latent image carrier and the developing sleeve is In the same direction, the ratio of the peripheral speed of the organic latent image carrier to the peripheral speed of the developing sleeve was 1:2, and the DC bias voltage applied to the developing sleeve was -150V.

The results are shown in Table 3 below.

■ Fog The fog was determined by measuring the relative density of the white background portion of the copied image with the IrX draft density of OoO using a Sakura densitometer (manufactured by Konishi Roku Photo Industry Co., Ltd.).The white background reflection density was taken as OoO. In the evaluation, when the relative concentration was less than 0.01, it was evaluated as "○", when it was 0.01 or more and less than 0.03, it was evaluated as "△", and when it was 0.03 or more, it was evaluated as rXJ.

(2) Image Density [Sakura Densitometer] (manufactured by Konishiroku Photo Industry Co., Ltd.) was used to measure the relative density of a white background portion with an original density of 0.0 to the copied image.

0 image quality copy image, image dropout, image disturbance, image sweeping, gradation,
Visual judgment was made from five viewpoints of sharpness. Evaluation,
A score of "○" indicates a good score, a score of "△" indicates a slight defect but still at a practical level, and a score of "×1" indicates a case of a poor score that is practically problematic.

"Image dropout" refers to the phenomenon in which part of the image is missing, and "image disturbance" refers to the phenomenon of irregular shading differences in the entire image and toner adhering to the periphery of the image. "Eye" refers to the phenomenon in which a linear difference in shading appears in an image.

■Resolution Following JIS Z 4916, the blade has 4.0, 5.0, 3 6° horizontal lines, 8.
Using a chart with 0 lines, the blades with discernible horizontal lines were displayed as resolution.

(2) Transfer rate After the transfer process, it was calculated by measuring the weight of the toner transferred to the transfer paper and the weight of the toner remaining on the organic latent image carrier.

■Toner scattering Visually observe the inside of the copying machine and the copied image. If the condition is good with almost no toner scattering, mark it as "○." If there is some toner scattering, but it is at a practical level, mark it as "○."
Δ", and cases where a lot of toner scattering was observed and there was a practical problem were designated as 1×".

■Cleanability After repeatedly forming an image, the surface of the organic latent image carrier was visually observed immediately after being cleaned with a cleaning blade, and the judgment was made based on the presence or absence of deposits on the surface of the organic latent image carrier. . The evaluation is "○" if the product is in good condition with almost no deposits observed, "Δ" if some deposits are observed but at a practical level, and "Δ" if there are many deposits found and it is of practical use. was set as [x].

(2) Test 2 (live photo test under high temperature environmental conditions)
) A photo test was conducted in the same manner as in Test 1, except that the environmental conditions were a high temperature and high humidity environment of 33° C. and 85% relative humidity, and the above items were evaluated. The results are shown in Table 4 below.

As can be understood from the results in Tables 3 and 4 below, according to the developer of the present invention, in the development process, the negative charge latent formed on the organic latent image carrier by the magnetic brush development method is Development with good gradation and resolution can be achieved without image fogging, image deletion, image sweeping, toner scattering, or decrease in image density, and in the transfer process, the electrostatic transfer means eliminates image disturbance. It is possible to transfer at a high transfer rate without deteriorating gradation or resolution, and in the cleaning process, it can be cleaned well using a cleaning blade with a simple structure. It is possible to form a clear image with high image density, good gradation, and resolution, with no image disturbance, image sweeping, or glaring phenomenon.

Further, even when performing the image forming process many times, it is possible to stably form a good image.

In addition, good images can be stably formed many times even in high-temperature environments.

In addition, Examples 4 and 5 give much better results than the comparative examples, but the results are inferior in gradation and resolution between the Examples, and the amino-modified surface treatment of the silica particles Amino-modified silicone oil, rather than silane coupling agent and silicone oil
This indicates that silicone rubber and silicone resin are preferred.

It is clear from the table that the comparative examples have many practical problems compared to the above examples.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an electrostatic image developing apparatus that can be suitably used to carry out development using the developer of the present invention. 10--One organic latent image carrier 10^---Conductive support 10B-m-Photosensitive layer 11-m-Developing sleeve 12--Magnet roll 13-m-Regulation blade 17--Developer layer ( magnetic brush) 18-m-DC bias power supply

Claims (1)

[Claims] A negatively charged latent image developer containing a coated carrier, a nonmagnetic toner, positively charged silica fine particles, and a fatty acid metal salt.