JPH08194328A - Electrostatic charge developing toner composition and image forming method - Google Patents

Abstract

PURPOSE: To provide an electrostatic charge image developing toner compsn. which does not impart damage to the surface of a latent image carrying member, drastically suppresses its wear, does not induce filming, etc., on the surface of the latent image carrying member and cleaning member and has stable repeating characteristics and an image forming method capable of forming images having high reliability over a long period of time without troubles in image quality, such as drop-outs, fogging, degradation in density, image blur and black stripes. CONSTITUTION: This electrostatic charge image developing toner compsn. consists of toner particles contg. a binder resin and coloring agents, resin particulates and mica particulates. At least either of the resin particulates or the mica particulates are treated with a silicone oil. This image forming method has a stage for forming a latent image on the latent image carrying member, a stage for developing this latent image by using the electrostatic charge image developing toner compsn., a stage for transferring the developed toner image onto a transfer medium and a stage for heat fixing the toner image on this transfer medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner composition for developing an electrostatic charge image for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like, and an image forming method using the same. .

[0002]

2. Description of the Related Art An electrostatic latent image formed on a photoconductor, such as an electrophotographic method, is developed with a developer, and a toner image on the photoconductor is transferred to a transfer medium such as paper or sheet, and then heated. It is used to obtain a permanent image by fixing using pressure, solvent, etc.
Further, at that time, the toner remaining on the photoconductor is removed from the photoconductor by the cleaning device. Therefore, in order for the electrophotographic method to be completed as a system having stable repeating characteristics, it is necessary that each process for forming an image be fully functional. Among these processes, in the cleaning process, the photoconductor and the cleaning member are in direct contact with each other, which causes damage such as scratches and abrasion on the photoconductor surface, filming, and image quality defects due to poor cleaning. May occur. Therefore, a high cleaning property is required in the cleaning process. In recent years, the use of recycled paper has increased to save resources. Generally, recycled paper produces a large amount of paper dust. Therefore, there is a problem of causing cleaning failure such as the above, and further higher cleaning performance is required.

Conventionally, it has been proposed to externally add various additives to toner particles in order to improve fluidity, durability, or cleaning property. For example, it has been proposed to obtain a toner by adding fine powder of an inorganic compound such as silica, alumina or titania (Japanese Patent Laid-Open No. 59-226).
355, JP 61-23160, JP 63-118757, JP 2-1870, JP 2-90175, etc.). However,
Since fine powders of inorganic compounds such as silica, alumina, and titania have high hardness, there are problems that the surface of the photoconductor is likely to be indented or scratched, and that toner is likely to stick to the scratched portion.

In order to solve these problems, a method of externally adding a fatty acid metal salt, polyolefin or the like as an additive to the toner particles has been studied (Japanese Patent Laid-Open No. 54-16219).
JP, JP-A-60-198556, JP, JP-A-61
-231562, JP-A-61-231563, etc.). However, all of the fatty acid metal salts and polyolefins disclosed in the above publications have an initial effect, but since the additive itself has a property of easily filming on the photoreceptor, repeated cleaning is performed. In the meantime, due to the pressure between the photoconductor and the cleaning member, non-uniform filming occurs on the photoconductor surface, resulting in a decrease in density due to the decrease in the sensitivity of the photoconductor, fog, white spots in the image, image defects such as image blurring. There is a problem of causing.

On the other hand, when copying is repeated for a long time using an organic photoconductor, the surface layer of the photoconductor wears, causing a leak when the organic photoconductor is charged, a black spot appears on an image, and a film of the surface layer. There is a problem in that the thickness is reduced due to wear, electrical characteristics are changed, and it becomes difficult to maintain the image quality of a copied image.

[0006]

However, the present situation is that no effective means has been found for the above problems. The present invention has been made for the purpose of solving the above-mentioned problems in the prior art. That is, the object of the present invention, in the cleaning step, without damaging the surface of the latent image carrier such as the photoconductor or the dielectric,
Another object of the present invention is to provide a toner composition for developing an electrostatic charge image, in which abrasion is remarkably controlled, a filming phenomenon or the like does not occur on the surface of a latent image carrier or a cleaning member, and the repeating characteristics are stable. Another object of the present invention is to provide an image forming method capable of forming a highly reliable image for a long period of time without causing image defects such as white spots, fog, density reduction, image blur, and black streaks. .

[0007]

The electrostatic charge image developing toner composition of the present invention comprises toner particles containing a binder resin and a colorant, and resin particles and mica particles.
At least one of the resin fine particles and the mica fine particles is treated with silicone oil. The image forming method of the present invention comprises a step of forming a latent image on a latent image carrier, a step of developing the latent image with a developer, a step of transferring the developed toner image onto a transfer body, and a transfer body. Comprising a step of heating and fixing the above toner image,
The above toner composition for developing an electrostatic image is used as a developer.

The present invention will be described in detail below. The binder resin and the colorant, which are the constituent components of the toner particles of the present invention,
A conventionally known one is used. Typical binder resins used are styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate. Α-methylene fats such as vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate. Homopolymers and copolymers of vinyl ethers such as group 1 monocarboxylic acid esters, vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, etc. It can be exemplified the body. Particularly typical binder resins include polystyrene resin, polyester resin, styrene-
Examples thereof include alkyl acrylate copolymers, styrene-alkyl methacrylate copolymers, styrene-acrylonitrile copolymers, polyethylene resins and polypropylene resins. Furthermore, polyurethane resin, epoxy resin, silicone resin, polyamide resin, modified rosin, paraffins, waxes and the like can be mentioned. Among these resins, styrene resin and polyester resin are particularly preferably used.

Known pigments, dyes and the like are used as the colorant, and typical examples thereof include carbon black, aniline blue, calcoil blue, chrome yellow, DuPont oil red, quinoline yellow and phthalocyanine. Blue, Rose Bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 1
22, C.I. I. Pigment Red 57: 1, C.I. I.
Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow Blue 1
5: 1, C.I. I. Pigment Blue 15: 3 and the like. The content of these colorants is preferably in the range of 2% by weight to 8% by weight with respect to the toner particles. Further, the coloring agent may be formed of a magnetic material, and a part or all of the coloring agent can be replaced with the magnetic material. Examples of the magnetic material include ferrite having an average particle size of 0.1 to 2 μm, magnetite, γ-iron sesquioxide, chromium oxide, various fine metal powders, and the like. Especially ferrite,
Magnetite is preferably used. The content of the magnetic material is preferably 20 to 70% by weight with respect to the toner particles.

A charge control agent may be added to the toner particles, if desired. As the charge control agent, known compounds can be used, but it is preferable to use an azo metal complex, a salicylic acid metal complex, nigrosine or a quaternary ammonium salt. Further, an offset preventive agent such as low molecular weight polypropylene, low molecular weight polyethylene, or wax can be added. The toner particles comprising the above components in the present invention may be capsule toner. The average particle size of the toner particles is preferably in the range of 3 to 20 μm.

In the present invention, resin particles and mica particles are added to the toner particles as external additives, but it is necessary that at least one of the resin particles and the mica particles is treated with silicone oil. . Examples of the resin fine particles include acrylic resin,
Styrene resin, silicone resin, and fluorine resin can be used. Acrylic resins and styrene resins are preferable, and those containing methyl acrylate as a monomer component are particularly preferable from the viewpoint of maintainability. The particle size of the resin fine particles is preferably in the range of 0.05 to 5 μm, and particularly preferably in the range of 0.1 to 2 μm. Further, as the mica fine particles, aluminum, potassium,
Silicic acid compounds such as magnesium, sodium and iron are preferable, and those having a size of 0.005 to 0.002 μm are preferably used.

The resin fine particles can be produced by a known method. For example, it can be produced by suspension polymerization using a dispersion aid, emulsion polymerization using an emulsifier, and the like. Examples of the silicone oil that can be used for treating the resin fine particles and the mica fine particles include dimethyl silicone oil, methylphenyl silicone oil, amino group-containing silicone oil, fluorine-modified silicone oil, and mercapto-modified silicone oil.

In order to produce fine resin particles treated with silicone oil, the fine resin particles are added to silicone oil dissolved in a solvent such as alcohol, mixed and dispersed, and then dried by an evaporator to remove the solvent. However, the resin fine particles containing the silicone oil may be prepared by using the resin as the silicone oil during the synthesis of the resin. For example, silicone oil may be added to a monomer for resin synthesis or may be added at the time of polymerization to prepare fine resin particles. When the mica fine particles are treated with silicone oil, as in the case of the resin fine particles, the mica fine particles can be added to silicone oil dissolved in a solvent, mixed and dispersed, and then dried. .

The amount of silicone oil treated is in the range of 5 to 40% by weight, preferably 10 to 30% by weight, based on the resin fine particles or mica fine particles. When the treatment amount is lower than 5% by weight, the desired effect of the present invention cannot be sufficiently obtained, and when the treatment amount is higher than 40% by weight, the resin fine particles or mica fine particles treated with silicone oil are likely to aggregate. The fluidity of the toner particles is impaired.

In the present invention, the above resin fine particles and mica fine particles are each contained in an amount of 0.1 to 0.1 with respect to the toner particles.
It is added in the range of 2.0% by weight and 0.1 to 1.0% by weight. The mixing ratio of the resin fine particles and the mica fine particles is in the range of 20:90 to 90:10.

In the present invention, in addition to the above resin fine particles and mica fine particles, other external additives for improving the fluidity of the toner may be added to the toner particles. For example, addition of inorganic oxide fine particles such as SiO ₂ , TiO ₂ , and Al ₂ O ₃ , or those obtained by treating the surface of the fine particles with a silane coupling agent, titanium coupling agent, resin, charge control agent, etc. You can

Next, the image forming method of the present invention will be described. As the latent image bearing member used in the step of forming a latent image on the latent image bearing member, an electrophotographic photosensitive member having an outermost surface made of an organic material and a dielectric substance are used. As the electrophotographic photosensitive member, known ones such as one having a surface layer made of an organic photosensitive layer in which a photoconductive material is dispersed in a binder resin and one having a protective layer formed of a synthetic resin are used. Specifically, a charge transport layer in which a charge transport agent is dispersed in a polycarbonate resin is used. As the dielectric whose outermost surface layer is made of an organic material, a dielectric having a dielectric layer made of a synthetic resin such as polyester or polycarbonate on a substrate is used. The latent image can be formed by a conventional method. For example, in the case of an electrophotographic photoreceptor, it can be uniformly charged by contact with a corona charger or a bias roll, and then imagewise exposed. The step of developing the formed latent image with a developer is performed using the above-described toner composition for developing an electrostatic charge image, and the toner composition for developing an electrostatic charge image is used as a one-component developer. May also be used as a two-component developer. The developed toner image is transferred onto a transfer body such as transfer paper by a corotron or a bias applying transfer roller in a transfer process, and then is heat-fixed in a fixing process to form an image. On the other hand, the toner remaining on the latent image carrier is cleaned by the cleaning member and is used in the next copying operation.

[0018]

In the toner composition for developing an electrostatic image of the present invention, the externally added resin fine particles have a hardness lower than that of the inorganic oxide fine particles and have a relatively large average particle diameter of 0.05 μm or more. The contact between the latent image carrier surface and the toner particles, or when the inorganic oxide fine particles are externally added, the contact between the latent image carrier surface and the inorganic oxide fine particles can be controlled. Mica has the effect of reducing the friction coefficient of toner particles, but since the resin particles and / or mica is treated with silicone oil, the friction coefficient between the surface of the latent image carrier and the toner particles is significantly reduced. Is considered to be retained over a long period of time. Therefore, when the toner composition for developing an electrostatic image of the present invention is used, the transfer efficiency at the time of transfer is improved, and there is an effect that a part of an image is not lost even when transferring by a bias transfer roll.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. All "parts" mean parts by weight. Example 1 <Production of Magnetic Toner Particles> Styrene-butyl acrylate copolymer (80/20) 100 parts (Mw = 2.0 × 10 ⁵ , Mn = 4,000, Tg = 62 ° C.) Magnetic substance (EPT1000, Toda Kogyo Co., Ltd.) 45 parts Low molecular weight polypropylene 3 parts (Viscole 660p, Sanyo Chemical Co., Ltd.) Charge control agent (Spiron Black TPH, Hodogaya Chemical Co., Ltd.) 2 parts The above components are melt-kneaded by a twin-screw extruder. After cooling, it was finely pulverized by a jet mill and further classified by a classifier to obtain magnetic toner particles having an average particle size (volume) of 10 μm.

<Production of Silicone Oil Treated Resin Fine Particles> 20 parts of dimethyl silicone oil is mixed with 50 parts of ethanol.
It was dissolved in 0 part, and this solution was mixed with 100 parts of polymethylmethacrylate resin having an average particle diameter of 0.5 μm and stirred, and then ethanol was distilled off using an evaporator and dried. Next, the obtained dried product was disintegrated using a mortar and sieved with a 105 μm mesh sieve to obtain resin fine particles treated with dimethyl silicone oil.

<Production of mica fine particles treated with silicone oil> 20 parts of dimethyl silicone oil was mixed with 5 parts of ethanol.
It is dissolved in 100 parts and the average particle size is 0.01 μm.
The mixture was mixed with 100 parts of the mica fine particles (1) and stirred, and then ethanol was distilled off using an evaporator and dried. Next, the obtained dried product is crushed using a mortar,
Sieving with a sieve having a mesh of μm gave mica fine particles treated with dimethyl silicone oil.

<Production of Magnetic Toner Composition> To 100 parts of the above magnetic toner particles, hydrophobic silica (R) is added as an external additive.
972, manufactured by Nippon Aerosil Co., Ltd.), 0.5 part of the silicone oil-treated resin fine particles, and 0.2 part of the silicone oil-treated mica fine particles are added and mixed by a Henschel mixer to obtain a magnetic toner composition. It was

Example 2 A magnetic toner composition was obtained in the same manner as in Example 1, except that untreated mica fine particles were used in place of the silicone oil-treated mica fine particles. Example 3 A magnetic toner composition was obtained in the same manner as in Example 1, except that untreated polymethylmethacrylate resin fine particles were used in place of the silicone oil-treated resin fine particles.

Comparative Example 1 In Example 1, as an external additive, hydrophobic silica (R9
72, manufactured by Nippon Aerosil Co., Ltd.) was used, and a magnetic toner composition was obtained in exactly the same manner. Comparative Example 2 In Example 1, as an external additive, hydrophobic silica (R97
2, manufactured by Nippon Aerosil Co., Ltd.), and the addition amount is
A magnetic toner composition was obtained in exactly the same manner except that 5 parts was changed to 1.0 part. Comparative Example 3 Except that in Example 1, untreated mica fine particles were used in place of the silicone oil-treated mica fine particles, and untreated polymethylmethacrylate resin was used in place of the silicone oil-treated resin fine particles. A magnetic toner composition was obtained in the same manner. Comparative Example 4 A magnetic toner composition was obtained in the same manner as in Example 1, except that the resin particles treated with silicone oil were not used. Comparative Example 5 A magnetic toner composition was obtained in the same manner as in Example 1 except that the silicone oil-treated mica fine particles were not used.

A continuous copying test was conducted on the above magnetic toner composition. That is, the above magnetic toner composition was introduced into a copying machine (Vivace 200, manufactured by Fuji Xerox Co., Ltd.) modified to enable bias roll charging, bias roll transfer, and reversal development, and the temperature was kept at 20 ° C. and 50% RH.
The continuous copying test of 100,000 sheets was conducted under the environment. The image density and transfer efficiency at the initial stage and after copying 100,000 sheets, the amount of wear of the photoconductor (μm) after copying 100,000 sheets, the toner adhesion to the photoconductor, and the image quality defect were evaluated. Table 1 shows the evaluation results. In the evaluation of the image density, ◯ means that there is no fog and that a density of 1.4 or more can be obtained by the Macbeth densitometer. The transfer efficiency is a value calculated by measuring the weight of the transferred toner amount by performing tape transfer of the toner image on the photoreceptor before and after transfer to plain paper using a solid patch. 95% or more, △ 90% or more, 9
Less than 5%, x means less than 90%.

[0026]

[Table 1]

[0027]

As described above, the toner composition for developing an electrostatic image of the present invention uses resin fine particles and mica fine particles as external additives, and at least one of them is treated with silicone oil. Thus, in the cleaning step, the surface of the latent image carrier such as the photoconductor and the dielectric is not damaged, and the wear is remarkably suppressed, and the filming phenomenon or the like does not occur on the surface of the latent image carrier and the cleaning member. Thus, it becomes possible to obtain an image with stable repeatability for a long period of time. Therefore, according to the image forming method of the present invention, high image density, white spots,
There are no image defects such as fog, density loss, image blur, and black streaks.
It is possible to obtain a highly reliable image for a long period of time.

Front page continuation (72) Inventor Atsuhiko Eguchi 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture, Fuji Xerox Co., Ltd.

Claims (2)

[Claims] 1. A toner particle containing a binder resin and a colorant, resin particles and mica particles, wherein at least one of the resin particles and the mica particles is treated with silicone oil. And a toner composition for developing an electrostatic image. 2. A step of forming a latent image on a latent image carrier, a step of developing the latent image with a developer, a step of transferring the developed toner image onto a transfer body, and a toner on the transfer body. An image forming method comprising a step of heating and fixing an image, wherein the toner composition for developing an electrostatic image according to claim 1 is used as the developer.