JP3486429B2 - Image forming method and image forming toner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for developing an electrostatic charge image formed by an electrophotographic method, an electrostatic printing method or the like using a two-component developer.

More specifically, an image is formed by using an amorphous silicon photoconductor as a photoconductor in a direct or indirect electrophotographic development method and a developer containing at least toner particles obtained by an aqueous suspension polymerization method as a developer. Regarding the method.

[0003]

2. Description of the Related Art The electrophotographic method is described in US Pat. No. 2,297,
As described in Japanese Patent No. 691 etc., a number of methods are known. Generally, a photoconductive substance is used to form an electric latent image on a photoconductor by various means. Is developed with toner, and the toner image is transferred to a recording material such as paper, if necessary, and then fixed by heating, pressure, solvent vapor or the like to obtain a copy. Further, as a method of developing with toner or a method of fixing a toner image,
Conventionally, various methods have been proposed, and methods suitable for respective image forming processes have been adopted.

In recent years, high-speed copying and high image quality have been required for electrophotography. One of the approaches from the toner side to meet this requirement is to use a toner produced by an aqueous suspension polymerization method.

That is, in the conventional toners used for these purposes, a coloring agent composed of a dye and a pigment is generally melt-mixed in a thermoplastic resin and uniformly dispersed, and then a desired particle diameter is obtained by a fine pulverizer and a classifier. Manufactured by a grinding method to produce a toner having. Although this method of manufacture can produce fairly good toners, it has certain limitations, ie, the choice of toner materials. For example, the resin colorant dispersion must be sufficiently brittle to be comminuted in an economically feasible manufacturing apparatus. However, if the resin colorant dispersion is made brittle in order to satisfy such requirements, the particle size range of the particles formed when actually pulverized at a high speed tends to be wide, and in particular, a relatively large proportion of fine particles is The problem of inclusion arises. Further, such a brittle material is likely to undergo further fine pulverization or pulverization when used for developing such as a copying machine. Further, in this method, it is difficult to completely uniformly disperse solid fine particles such as a colorant in the resin, and depending on the degree of the dispersion, increase in fog,
Care must be taken to disperse it, as it may cause deterioration of image density and poor color mixing and transparency. In addition, the exposure of the colorant on the fracture surface may cause fluctuations in the developing characteristics.

On the other hand, in the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer. After forming a composition, this monomer composition is dispersed in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase, using a suitable stirrer, and a polymerization reaction is simultaneously performed to obtain a desired particle size. Obtaining toner particles.

Since this method does not include a crushing step at all, the toner does not need to be brittle, and the exposure of the colorant to the surface of the particles does not occur, which is required for high image quality. It has the advantage of having uniform triboelectric charging properties.

In addition, compared with the pulverization method, the polymerized toner is more likely to have a uniform shape, so that the toner rides on the latent image on the photosensitive drum at a high density, and an image more faithful to the latent image can be obtained. I have come to understand that. For this reason, the digital reversal development method has been attracting attention in recent years because halftone gradation is required in the trend of higher image quality. In this development method as well, toner faithfully adheres to the latent image on the photoconductor. Because of, the image with excellent gradation can be obtained.

Further, in order to improve the resolution, many researches and developments for reducing the particle size of the toner are currently underway. In this respect as well, the classification efficiency tends to decrease as the particle size becomes smaller in the pulverization method. On the other hand, in the polymerization method, a sharp particle size distribution is obtained regardless of the particle size, so that the production efficiency,
There are advantages such as saving energy.

Furthermore, in order to meet the demand for higher speed copying machines in recent years, further improvement in fixing property is required.
The polymerized toner has excellent properties also in this respect.

That is, as disclosed in Japanese Patent Laid-Open No. 61-46955, it is possible to include a large amount of release agent, which is impossible with pulverized toner, so that fixing in a wide temperature range is possible.

As described above, the polymerized toner has excellent characteristics in both high image quality and fixability.

On the other hand, as a commonly used photoreceptor,
Currently known are Se, CdS, OPC (organic photoconductor), amorphous silicon (hereinafter referred to as a-Si), and the like.

The Se type photoconductor is a traditional photoconductor that has been used since the earliest days of electrophotographic technology, and since it has excellent photosensitivity and durability as its characteristics, it is widely applied in practice. At present, SeTe, which has a higher color sensitivity and a higher photosensitivity than pure selenium, is mainly used. However, even with this, the heat resistance, abrasion resistance, mechanical strength, and aging properties of the Se photoconductor are inherently possessed. It has a stability problem. Further, since it is toxic, it is necessary to be careful when treating waste toner.

The OPC system has been practically used due to the discovery of an excellent sensitizer and the development of a sensitizing method. However, since the drum is easily scratched due to its durability, cleaning failure and toner adhesion on the OPC system occur. It has a drawback that (filming) is likely to occur.

As described above, the Se-based and OPC-based photoreceptors do not satisfy all of sensitivity, durability, and pollution-free property.
With respect to the movement of high-speed copying, it is necessary to compensate each defect by toner or process.

In contrast to these photoconductors, the a-Si photoconductor is essentially harmless, has a high photosensitivity over the entire visible region, and has a high hardness (as shown in Japanese Patent Publication No. 60-35059). The Se photoconductor has a Vickers hardness of 60 to 1,000 with respect to the Vickers hardness of 60, and is excellent in mechanical abrasion. Then, a surface protective layer for further improving the optical conductivity and durability of the a-Si photoconductor is provided as disclosed in Japanese Patent Publication No. 60-35059 and Japanese Patent Publication No. 3-15739. Therefore, there is a feature that the cleaning member can be sufficiently brought into pressure contact with the photosensitive member for cleaning.

For this reason, it is not necessary to greatly change the toner or the process in the pulverized toner due to problems such as filming and cleaning failure.

However, when a printing durability test is performed using a polymerized toner containing a release agent and an a-Si photoconductor, a phenomenon in which toner adheres to the photoconductor and fatigue deterioration (toner filming) is likely to occur. I understand. Further, since this phenomenon is likely to occur particularly in an environment of high temperature and high humidity, it has been speculated that the above-mentioned polymerized toner is likely to be fused due to impact.

[0020]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide an image forming method for visualizing an electrostatic latent image formed on an a-Si photoconductor. is there.

Another object of the present invention is to provide an image forming method capable of obtaining an image excellent in fine line reproducibility and image fidelity even at high speed copying.

A further object of the present invention is to provide an image forming method excellent in image quality stability.

A further object of the present invention is to provide an image forming method capable of obtaining an image having a stable fixing property.

[0024]

The object of the present invention is achieved by the following constitutions. That is, it consists of a developer carrier that carries a developer on the surface and silicon, carbon, and hydrogen.
A positively chargeable amorphous silicon photosensitive member having a surface layer of the amorphous film was placed with a certain distance in the developing unit, and carries the developer on the developer carrying member and conveyed to the developing unit, the positively charged positive developer digital latent image formed on the sex amorphous silicon photosensitive member has
In the image forming method of developing with a chargeable toner,
Positively chargeable toner consists of (a) colorant and (b) binder resin.
Styrene-based monomer and acrylic acid ester
Monomer classes, and, (c) a melting point of the polymerizable monomer composition having a polyalkylene 50 to 120 ° C. obtained by suspension polymerization in an aqueous medium, a colorant, a binder resin
And toner particles containing polyalkylene , and the toner particles
At least and an external additive is an external additive to the child,
If the content of the polyalkylene is styrene monomer and acetic acid.
Binder resin 10 produced from monomers of phosphoric acid esters
0 5 to 30 parts by weight per part by weight, and in XPS measurement of the toner surface component ratio is achieved by an image forming method, wherein the abundance ratio of the polyalkylene is less than 5 wt%.

One of the features of the present invention is to use an a-Si photosensitive member having an a-Si layer as a photosensitive layer on a conductive substrate as an electrostatic charge image carrier.

Since the a-Si photoconductor is excellent in heat resistance and abrasion resistance and excellent in durability, the image forming method of the present invention using the a-Si photoconductor is performed at high speed in a copying machine or the like. It has an advantage in realization.

Further, as a structure of the a-Si photosensitive member, a lower charge injection preventing layer may be provided below the photosensitive layer to prevent charges from entering from the substrate.

To further improve durability, a surface protective layer is provided on the photosensitive layer, and an upper charge injection preventing layer for preventing injection of latent image charges from the surface of the electrostatic image carrier is provided on the photosensitive layer, or
It can also be provided between the surface protective layer and the photosensitive layer.

A layer which also serves as a surface protective layer and an upper charge injection preventing layer may be provided on the photosensitive layer.

Further, a long-wavelength light absorbing layer may be provided to prevent the appearance of interference development of long-wavelength light.

At this time, in order to adapt the characteristics of each layer to practical use, hydrogen atoms, boron, aluminum,
Group III atoms of the periodic table such as gallium, germanium,
Atoms of Group IV of the periodic table such as tin, atoms of Group V of the periodic table such as nitrogen, phosphorus and arsenic, atoms of Group VI of the periodic table such as oxygen, sulfur and selenium, and halogen atoms such as fluorine, chlorine and bromine. , Or singly or in combination, can be introduced at the time of forming a-Si to control each characteristic.

By using such an electrostatic charge image carrier, a digital latent image at a laser spot from a semiconductor laser or the like can be formed on the electrostatic charge image carrier.

For example, hydrogenated a-Si is used for the photosensitive layer, phosphorus-doped hydrogenated a-Si is used for the lower charge injection prevention layer, and
If hydrogenated a-Si doped with boron is provided in the upper charge injection prevention layer, it can be used as a photosensitive drum that holds a negatively charged electrostatic charge image.

On the other hand, boron-doped hydrogenated a-Si
Can be used as a lower charge injection prevention layer, and an amorphous film composed of silicon, carbon, and hydrogen (hereinafter referred to as hydrogenated a-SiC) can be provided as a surface protection layer to form a photosensitive drum that holds positive charges. .

Another feature of the present invention is that a toner containing a large amount of polyalkylene and having almost no polyalkylene on the toner surface is used.

The toner in which polyalkylene is unevenly distributed, which is a feature of the present invention, can faithfully reproduce even dots and fine lines of a latent image formed on a photoconductor, and has gradation and resolution. Gives an excellent image to. Further, the effect of the polyalkylene, which is a release agent, is exerted at the time of fixing, so that an image having excellent fixability is obtained.

The reason why such effects, particularly filming under high temperature and high humidity, is suppressed in the toner according to the present invention is not clear, but it is presumed as follows.

[0038]

In order to provide the polymerized toner with a fixing property, a toner containing a large amount of wax, polyalkylene or the like has been conventionally obtained as disclosed in JP-A-61-46955. However, when these toners are repeatedly developed and transferred on a photoconductor having a very hard surface such as a-Si, the toners are destroyed by contact with a cleaning member or by contact of ears on the developer carrying member. It was found that the release agent adheres strongly to the surface of the photoconductor.

That is, it is estimated that the filming of the polymerized toner on the a-Si photosensitive member is caused by the adhesion of the release agent due to the destruction of the toner.

Therefore, when a direction for reducing the above-mentioned destruction or reducing the influence of the above-mentioned destruction is searched from the toner, if the polyalkylene component on the toner surface is within the range of the present invention, a great effect on filming is obtained. Has been found to be obtained.

Since the toner of the present invention has almost no polyalkylene in the surface layer even in an environment of high temperature and high humidity, the cohesive force between the toner and between the toner and the a-Si photoreceptor is small.
It is easily peeled off from the surface of the photoconductor, and the transferability and cleaning property are improved.

Further, since the polyalkylene is unevenly distributed inside the toner, the surface of the toner becomes relatively hard and strong against physical impact.

The present invention will be described in more detail.

As the constitution of the a-Si photosensitive member provided with the surface protective layer , any photosensitive member manufactured by a known method such as Japanese Patent Publication No. 60-35059 and Japanese Patent Publication No. 3-15739 can be used. It can be anything. However, since the amount of ozone, which is a by-product of corona charging used for forming an electrostatic latent image, is generally larger in the negatively charged photoreceptor , a positively charged photoreceptor is used.
It

A cleaning member may be attached to the a-Si photoconductor of the present invention. The cleaning method used for the a-Si photosensitive member of the present invention may be any of known techniques such as a blade method of cleaning with a blade of nylon, silicon or the like, or a brush method of cleaning with a brush. The blade method is preferable for reasons such as chemical conversion.

In the present invention, the binding of polyalkylene
The content with respect to 100 parts by weight of the resin may be 2 to 40 parts by weight from the viewpoint of imparting fixability, and more preferably 5 to 5 parts by weight.
It is preferably 30 parts by weight. When the amount of polyalkylene is less than 5 parts by weight, low-temperature fixability and offset resistance are deteriorated, and when the amount is less than 2 parts by weight, fixing becomes substantially difficult.

Further, when the amount of polyalkylene exceeds 30 parts by weight, the impact resistance against the a-Si drum is reduced, and thus the filming resistance in a high temperature and high humidity environment is reduced,
If the content exceeds 40 parts by weight, filming tends to occur.

Further, in the present invention, X on the toner surface is
In PS measurement, the amount of polyalkylene present may be less than 5% by weight, and more preferably 1% by weight or less.

When the amount of polyalkylene present on the toner surface is 5% by weight or more, the adhesive force of the polyalkylene to the a-Si photoconductor becomes large, and the impact of the developer spike on the developer carrying portion and the cleaning member, Since it is more susceptible to friction, filming is more likely to occur.

As means for preventing the presence of such polyalkylene on the toner surface, a method of seed polymerization using suspension-polymerized particles as nuclei, as in JP-A-59-62870, or JP-A-61-46955 is disclosed. Although many methods such as a method of adding a polar resin having poor compatibility with polyalkylene are disclosed, any means can be used as long as they fall within the scope of the present invention by these known methods. good.

The present inventors have found that among these known methods, the method of adding a polar resin promotes uneven distribution of polyalkylene and is more effective when combined with other known methods. In the present invention, the addition of polar substances is considered essential.

In the analysis of the toner surface by XPS of the present invention, the following measuring device and measuring conditions can be exemplified. (Method) X-ray photoelectron spectroscopy (XPS) (apparatus) ESCALAB5 manufactured by VG (measurement condition) X-ray source; MgKα _1.2 X-ray output; 8 kV, 20 mA analyzer mode; constant analysis
zer energy (CAE) mode pass energy wide scan 50 eV, narron scan 20 eV resolution; Ag3d _5/2 FWHM = 1.0 eV slit; A4 vacuum degree; 1 × 10 ^-9 Torr horizontal axis correction; Cls of neutral carbon value. 284.6 eV
I chose

Examples of the polymerizable monomer that can be used in the above-mentioned polymerized toner include styrene-based monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene and p-ethylstyrene. , Methyl acrylate / ethyl acrylate / n-butyl acrylate /
Isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, acrylates such as phenyl acrylate, methyl methacrylate, etc. Ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate. Examples thereof include methacrylic acid esters such as diethylaminoethyl methacrylate and other monomers such as acrylonitrile, methacrylonitrile and acrylamide. These monomers may be used alone or in combination. Among the above monomers,
It is preferable to use styrene or a styrene derivative alone or in combination with other monomers from the viewpoint of developing characteristics and durability of the toner.

The present invention requires a polar component. The structure containing a polar component in the monomer has a polar component in the monomer, contains a monomer, or contains a polymer containing a polar component shown below, or It is preferable to use them together.

Examples of the polymer or copolymer having a polar component contained in the monomer used in the present invention include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, or styrene / unsaturated Copolymers with carboxylic acid esters, etc., nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid / methacrylic acid,
Other examples include unsaturated dibasic acids / unsaturated dibasic anhydrides, polymers such as nitro monomers or copolymers with styrene monomers, polyesters, epoxy resins and the like.

The amount of the polar polymer / copolymer added is preferably 0.1 to 10% by weight based on the total amount of the toner resin.

As the coloring agent used in the present invention, known coloring agents can be used. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Mordant Red 30, C.I. I. Direct Blue 1, C.I.
I. Direct Blue 2, C.I. I. Acid Blue 9,
C. I. Acid Blue 15, C.I. I. Basic blue 3, C.I. I. Basic Blue 5, C.I. I. Modant Blue 7, C.I. I. Direct Green 6, C.I. I.
Basic green 4, C.I. I. Basic green 6
Dyes such as yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG,
Tartrazine Lake, Molybdenum Orange, Permanent Orange GTR, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Navy Blue, Cobalt Blue, Alkali Blue Lake, Victoria Blue. There are pigments such as lake, quinacridone, rhodamine lake, phthalocyanine blue, fast sky blue, pigment green B, malachite green lake and final yellow green G. In the present invention, since the toner is obtained by using the polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the water phase transfer property of the colorant. It is better to apply chemical treatment. In particular, since many dye-based dyes have a polymerization inhibitory property, caution is required when using them. A preferred method of surface-treating a dye system is a method of polymerizing a polymerizable monomer in the presence of these dyes in advance, and the obtained colored polymer is added to the monomer system.

The color toner is preferably selected from a disazo yellow pigment, a quinacridone magenta pigment and a phthalocyanine cyan pigment.

When the toner is used as a magnetic toner, it may contain magnetic powder. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used.
There are powders of ferromagnetic metals such as iron, cobalt and nickel, and compounds such as magnetite and ferrite. In particular, in the present invention, since a toner is obtained by using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the water phase transfer property of the magnetic material, and preferably surface modification, for example, there is no polymerization inhibitory property. It is better to give a hydrophobic treatment with a substance.

The polyalkylene used in the present invention includes
It is selected from waxes such as paraffins and olefins, but it is preferable that the melting point is 50 to 120 ° C. by the DSC method.

In the present invention, it is desirable to add a charge control agent to the toner material in order to control the chargeability of the toner. As these charge control agents, among known ones, those having almost no polymerization inhibitory property / water phase transfer property are used. For example, as positive charge control agents, nigrosine dyes, triphenylmethane dyes, quaternary ammonium salts, guanidines are used. Derivatives, imidazole derivatives, amine-based and polyamine-based compounds, and the like. As a negative charge control agent, metal-containing salicylic acid-based compounds, metal-containing monoazo-based dye compounds, urea derivatives, styrene-acrylic acid copolymers, styrene-methacrylic Examples thereof include acid copolymers.

The addition amount of these charge control agents is 0.
1 to 10% by weight is preferable.

As the polymerization initiator, any suitable polymerization initiator, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1, 1'-azobis (cyclohexane-1-
Carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobis or diazo polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide,
Examples thereof include peroxide-based polymerization initiators such as diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide. These polymerization initiators are preferably added in an amount of 0.5 to 20% by weight of the polymerizable monomer, and may be used alone or in combination.

In the present invention, in order to control the molecular weight, known crosslinking agents and chain transfer agents may be added, and the preferable addition amount is 0.001 to 15% by weight.
Is.

As an additive for imparting various toner characteristics, from the viewpoint of durability in the toner or when added to the toner, the particle diameter is 1/10 or less of the volume average diameter of the toner particles. Is preferred. What is the particle size of this additive?
It means the average particle size of the toner particles obtained by observing the surface of the toner particles with an electron microscope. As the additives for imparting these characteristics, for example, the following ones are used.

1) Flowability-imparting agents: metal oxides (silicon oxide, aluminum oxide, titanium oxide, etc.), carbon fluoride, etc. Those subjected to a hydrophobic treatment are more preferable.

2) Abrasive: metal oxide (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitride (silicon nitride, etc.), carbide (silicon carbide, etc.), metal salt (calcium sulfate, etc.) , Barium sulfate, calcium carbonate, etc.).

3) Lubricants: Fluorine-based resin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salt (zinc stearate, calcium stearate, etc.), etc.

4) Charge controllable particles: Metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.) and the like.

These additives are used in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner particles. These additives are
They may be used alone or in combination.

Any suitable stabilizer is used in the dispersion medium used in the present invention. For example, as an inorganic compound, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate. , Bentonite, silica, alumina and the like. As an organic compound, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salt, starch and the like can be dispersed in an aqueous phase and used.
It is preferable to use 0.2 to 20 parts by weight of these stabilizers with respect to 100 parts by weight of the polymerizable monomer.

When an inorganic compound is used among these stabilizers, a commercially available one may be used as it is, but the inorganic compound may be produced in a dispersion medium in order to obtain fine particles. For example, in the case of tricalcium phosphate, it is advisable to mix the sodium phosphate aqueous solution and the calcium chloride aqueous solution under high stirring.

In order to finely disperse these stabilizers, 0.001 to 0.001 to 100 parts by weight of the polymerizable monomer is added.
0.1 part by weight of surfactant may be used. This is for promoting the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, and lauric acid. Examples include sodium, potassium stearate, calcium oleate, and the like.

The polymerized toner used in the present invention is obtained by the following method. That is, the release agent in the polymerizable monomer
A monomer system in which a colorant, a charge control agent, a polymerization initiator, and other additives are added, and the mixture is uniformly dissolved or dispersed by a homogenizer or an ultrasonic disperser is usually stirred in an aqueous phase containing a dispersion stabilizer. Disperse using a machine or homomixer / homogenizer. Granulation is preferably carried out by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size, generally 30 μm or less. After that, stirring may be performed to the extent that the particle state is maintained and the particles are prevented from settling due to the action of the dispersion stabilizer. The polymerization temperature is set to 40 ° C. or higher, generally 50 to 90 ° C. to carry out the polymerization. In addition, the temperature may be raised in the latter half of the polymerization reaction, and further in the latter half of the reaction or the end of the reaction in order to remove unreacted polymerizable monomers and by-products that may cause odor during toner fixing. The aqueous medium may be partially distilled off later. After the reaction is completed, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

Next, the present invention will be specifically described with reference to examples.

[0077]

EXAMPLES Example 1 First, the polymerization toner will be described.

To 7100 g of ion-exchanged water, 0.1M-N
It was charged a ₃ PO ₄ aqueous solution 4500 g, followed by heating to 70 ° C., using a TK-type homomixer (manufactured by Tokushu Kika Kogyo), and stirred at 12000 rpm. 1.0M-
68 g of CaCl ₂ aqueous solution was gradually added, and Ca ₃ (PO
₄ ) An aqueous medium containing ₂ was obtained.

On the other hand,   Monomer: Styrene 1650g               350 g of n-butyl acrylate   Colorant: Copper phthalocyanine pigment 100g   Charge control agent: quaternary ammonium salt 20 g   Polar resin: Styrene-dimethylaminoethyl 80g                 Methacrylate copolymer   Release agent: Paraffin wax (melting point 70 ° C) 250g

The above formulation was heated to 60 ° C. and uniformly dissolved and dispersed at 200 rpm using an attritor (manufactured by Mitsui Miike Kakoki Co., Ltd.). In addition to this, the polymerization initiator 2,2 '
-Azobis (2,4-dimethylvaleronitrile) 100
g was dissolved and a polymerizable monomer composition was prepared. The above polymerizable monomer composition was added to the aqueous medium, and the temperature was changed to 70 ° C.
Under a N ₂ atmosphere, the polymerizable monomer composition was granulated by stirring for 20 minutes at 10,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, while stirring with a paddle stirring blade, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours. At this time, the particle size was about 7.2 μm in weight average diameter.

After that, the mixture was cooled, hydrochloric acid was added to dissolve calcium phosphate, and then filtered, washed with water and dried to obtain colored suspended particles. Specific surface area by BET method is 200m ²
0.8 parts by weight of positively-charged hydrophobic silica having an amount of / g was externally added to obtain a suspension-polymerized toner. 95 parts by weight of an acrylic-coated ferrite carrier was mixed with 5 parts by weight of this toner to obtain a developer. The abundance ratio of paraffin wax on the surface of the toner was 1.5% by weight as a result of XPS measurement.

On the other hand, the a-Si photosensitive drum was manufactured as follows. The a-Si photosensitive drum is a high frequency plasma C
Using a VD device, SiH ₄ , H ₂ , CH ₄ , PH ₃ ,
It was prepared by a glow discharge method using a gas such as B ₂ H ₆ or GeH ₄ .

Hydrogenation a in which a trace amount of boron is doped on a substrate which is an aluminum cylinder of 80φ × 360 mm
A lower charge injection blocking layer and a photosensitive layer were provided by depositing —Si, and an amorphous film (surface layer) made of silicon, carbon, and hydrogen was provided thereon.

The a-Si photosensitive drum thus obtained was mounted on a CLC500 (manufactured by Canon Inc.), and the laser light amount and the like were modified so that positively chargeable toner could be used.

The developing conditions were a surface dark portion potential of 400 V, a surface bright portion potential of 100 V, and a DC bias of 300 V.

Further, a rubber blade having a nylon coating on the surface is used as a cleaning member, and the pressing pressure 1 is applied to the drum.
The contact was made so as to be 3 [kg / cm].

600 g of the positive charge image developer thus obtained.
Was put in a developing machine and subjected to a printing durability test in a high temperature and high humidity (35 ° C. 90% RH) environment. Filming did not occur even after printing 1000 sheets, and the fixing property was the same as in the initial stage. The image obtained was stable. The results are shown in Table 1.

Comparative Example 1 A printing durability test was conducted in the same manner as in Example 1 except that the paraffin wax formulation amount was 850 g in the toner formulation of Example 1, and filming occurred on the 20th sheet. It caused a white spot on the image. The results are shown in Table 1.
It was shown to.

Comparative Example 2 A printing durability test was conducted in the same manner as in Example 1 except that the styrene-dimethylaminoethylmethacrylate resin was not formulated in the toner formulation of Example 1, and filming occurred on the 30th sheet. have done. The results are shown in Table 1.

Example 2 Three kinds of toner in which the colorant in the toner formulation of Example 1 was changed to quinacridone magenta pigment, azo yellow pigment and carbon black, and the formulation amount of paraffin wax was changed to 600 g each. Was prepared and combined with the cyan toner of Example 1 to obtain a 4-color developer. When a printing durability test was conducted using these four color developers, a sharp image faithful to the original image was obtained.
Filming did not occur even in the 0 sheet printing durability test.

Example 3 A printing durability test was conducted in the same manner as in Example 1 except that 10 g of styrene-dimethylaminoethyl methacrylate resin was used in the toner formulation of Example 1, and an image with excellent fixing properties was obtained. was gotten. However, filming occurred at the time of 1000 sheets.

[0092]

[Table 1]

[0093]

According to the present invention, by using the above-mentioned toner having polyalkylene unevenly distributed in an image forming method using an a-Si photoconductor, an electrostatic charge image is faithfully visualized and a fog-free floor is obtained. Not only an image having excellent tonality can be provided, but also filming is suppressed, so that a stable image can be provided even in a printing durability test under high temperature and high humidity.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tatsuya Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kasuya Rare 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Incorporated (72) Inventor Takao Ishiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-4-101163 (JP, A) JP-A-61-28957 (JP , A) JP 5-88409 (JP, A) JP 5-61243 (JP, A) JP 3-264961 (JP, A) JP 3-243956 (JP, A) JP 3-274060 (JP, A) JP-A-4-66955 (JP, A) JP-A-3-11363 (JP, A) JP-A-62-247378 (JP, A) JP-A-62-178273 (JP, A) JP 61-26048 (JP, A) JP 60-257453 (JP, A) JP 60-225854 (JP, A) JP 60-225853 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/087 G03G 9 / 08 G03G 15/08

Claims (2)

(57) [Claims] 1. A surface of a developer carrying member carrying a developer on its surface and an amorphous film made of silicon, carbon and hydrogen.
A positively chargeable amorphous silicon photosensitive member having a surface layer and arranged with a predetermined interval in the developing unit, and carries the developer on the developer carrying member and conveyed to the developing unit, the positively charged
An image forming method for developing a positively charged toner developer a digital latent image formed on the sex amorphous silicon photosensitive member has, the positively chargeable toner, (a) a colorant, (b ) Stilt for forming the binder resin
Monomers and acrylic acid ester monomers, and
(C) Colorant, binder resin and polyalkylene obtained by suspension polymerization of a polymerizable monomer composition having a polyalkylene having a melting point of 50 to 120 ° C. in an aqueous medium.
Toner particles having a, the toner particles are at least and an external additive is an external additive, the content of the polyalkylene styrenic monomer and Accession
Binder resin 10 produced from monomers of phosphoric acid esters
0 5 to 30 parts by weight per part by weight, and in XPS measurement of the toner surface component ratio, an image forming method, wherein the abundance ratio of the polyalkylene is less than 5 wt%. 2. The toner particles include (a) a colorant and (b) a binder.
Styrenic Monomer and Acrylic for Forming Adhesive Resin
A polymerizable monomer composition having an acid ester monomer , (c) a polyalkylene having a melting point of 50 to 120 ° C., and (d) a polar polymer or a polar copolymer is suspended in an aqueous medium. the image forming method according to claim 1, characterized in der Rukoto those obtained by polymerizing.