JPH06194862A - Developer - Google Patents

Abstract

PURPOSE:To prevent filming due to a developer on a photosensitive body or developing rollers and to prevent decrease of picture density or separation of additives by mixing coloring fine particles with a specified amt. of org. fine particles obtd. by copolymn. of styrene and acrylonitrile with specified mixing ratio. CONSTITUTION:The developer consists of 100 pts.wt. of coloring particles consisting of a binder resin and a coloring agent, and 0.01-5 pts.wt. of copolymerized org. fine particles containing 50-99wt.% styrene and 1-50wt.% acrylonitrile. The coloring fine particles are sphere having >=0.8 sphericity and are preferable that the charge potential is negative. The org. fine particles are produced by polymn. method and are spherical particles having 0.01-3mum particle size and preferably -40 to -100muc/g electrification. The developer 4 is uniformly applied on a developer roll 2 by pressing a developing blade 3 to the surface of the developing roll 2 and the developing roll 2 is brought into contact with an electrostatic latent image on a photosensitive body 1 to execute developing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer, and more specifically, a non-magnetic one-component developer for visualizing an electrostatic latent image formed on a photoconductor or a dielectric by an electrophotographic device or an electrostatic recording device. Regarding

[0002]

2. Description of the Related Art Conventionally, as a developing method applied to an electrophotographic apparatus, an electrostatic recording apparatus, etc., a developer comprising colored fine particles and a carrier is used, and an electric charge is applied to the colored fine particles by frictional charging between the colored fine particles and the carrier. However, there is known a method of visualizing an electrostatic latent image with the colored fine particles. The visualized colored fine particle image on the photoconductor or the electrostatic recording body is transferred onto the transfer paper and then fixed to be a copy or a printed matter. On the other hand, after the transfer, it cannot be transferred on the photoconductor or the electrostatic recording body. The remaining colored fine particles are cleaned in preparation for the next step.

Cleaning of the residual colored fine particles is carried out by various methods such as a blade method, a brush method, a web method and a roll method. Coloring fine particles that cannot be completely removed by these cleaning methods gradually accumulate on the surface of the photoconductor or the like during a large number of copying or printing steps, and so-called cleaning failure or developer filming occurs. There is.

In order to improve such a phenomenon, for example, Japanese Patent Publication Nos. 48-8141, 51-1130, and Japanese Patent Laid-Open No.
0-120631, No. 52-84741, No. 60-
No. 186851 proposes a method of mixing an additive with a developer composition. That is, JP-B-48-8141 discloses organic polymers having a low surface energy such as polytetrafluoroethylene and polyvinylidene fluoride, and JP-B-51-11.
No. 30 is a polymer having a triboelectrification sequence smaller than sulfur and having no coating property, and JP-A No. 50-120631 is a polymer having a triboelectrification sequence smaller than sulfur and not coating property and an abrasive such as colloidal silica. In JP-A-52-84741, polystyrene particles are added to the developer, and in JP-A-60-186851, an acrylic polymer fine powder is added to a developer to reduce a sticking ability or a polishing effect. It is intended to prevent defective cleaning or filming of the developer on the surface of the.

As described above, the prevention of the above-mentioned phenomenon was initially investigated in the two-component developing system, but it has been found that the same phenomenon is also present in the other one-component magnetic or non-magnetic one-component developing system. That is, the above-mentioned phenomenon occurs in the developing sleeve and the developing blade in the magnetic one-component developing system, and similarly in the developing roller and the developing blade in the non-magnetic one-component developing system.

The above-mentioned method is useful to some extent in terms of preventing cleaning failure or filming of the developer, but when these developers are used for a long period of time, the colored fine particles are separated from the additives. The phenomenon occurs. That is, by copying or printing 5000 to 10000 sheets, the image density is partially lowered, and finally, a phenomenon that copying or printing cannot be performed occurs. According to the knowledge of the present inventor, since this phenomenon changes depending on the difference in chargeability of the organic fine particles, it is considered that the phenomenon is caused by the electrostatic adhesive force between the colored fine particles and the organic fine particles.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent filming due to a developer on a photosensitive member, a developing roller or a developing blade, and to prevent the reduction of image density and the separation of additives. It is to provide a developer for electrographic recording.

[0008]

Means for Solving the Problems As a result of earnest research by the present inventors, in place of conventional additives, a specific amount of organic fine particles obtained by copolymerizing styrene and acrylonitrile in a specific ratio is mixed with colored fine particles. It has been found that this solves the problem of separation between the colored fine particles and the additive as described above.

The developer of the present invention is based on the above findings. More specifically, 50 to 9 styrene is added to 100 parts by weight of colored fine particles composed of at least a binder resin and a colorant.
It is a mixture of 0.01 to 5 parts by weight of organic fine particles obtained by copolymerizing 9% by weight and 1 to 50% by weight of acrylonitrile.

According to a preferred aspect of the present invention, the above-mentioned development is such that the colored fine particles have a spherical shape, the sphericity is 0.8 or more, and the charged polarity of the colored fine particles is negatively chargeable. An agent is provided.

According to a preferred embodiment of the present invention, the organic fine particles are fine particles produced by a polymerization method, and the fine particles have a spherical shape and a particle size of 0.01 to 3 μm. To be done.

According to a preferred embodiment of the present invention, there is provided the above developer, wherein the organic fine particles have a charge amount of -40 to -100 μc / g.

According to a preferred embodiment of the present invention, a developing blade for controlling the layer thickness of the developer is arranged so as to be in pressure contact with the surface of the developing roll, and the developer is evenly coated on the surface of the developing roll, and Directly contact the developing roller with the electrostatic latent image,
Alternatively, there is provided the above-mentioned developer used in a method of developing by contacting it in a non-contact manner.

The present invention will be described in detail below. (Organic fine particles) As the organic fine particles used in the present invention, those fine particles polymerized by various polymerization methods can be used. That is, organic fine particles formed into particles by emulsion polymerization, soap-free emulsion polymerization, suspension polymerization, or the like, or a polymer obtained by each of the above-mentioned polymerization methods or solution polymerization, bulk polymerization, etc. is dissolved in a solvent, and then spray-dried or the like. Granulated organic particles or organic particles obtained by a method such as mechanical pulverization can be used.

The molecular weight of the copolymer constituting the organic fine particles according to the present invention is not particularly limited, and a copolymer having any molecular weight can be used within a range not departing from the object of the present invention.

The glass transition point of the copolymer constituting the organic fine particles is preferably room temperature (25 ° C.) or higher,
Furthermore, 50 ° C. or higher is preferable.

The organic fine particles according to the present invention are styrene 5
Organic fine particles obtained by copolymerizing a monomer composition of 0 to 99% by weight and acrylonitrile 1 to 50% by weight are preferable. If the amount of acrylonitrile is less than 1% by weight, the charge amount of the organic fine particles themselves becomes too low in absolute value, and the effect of preventing separation of the organic fine particles becomes insufficient. If the amount of acrylonitrile is more than 50% by weight, the absolute value of the charge amount becomes too high and the above effect becomes insufficient.

In the present invention, when the monomer composition is polymerized, the following monomers can coexist as long as the object of the present invention is not impaired.

Examples of such monomers include ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate. , Vinyl propionate, vinyl benzoate, and other vinyl esters; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, n-octyl methacrylate,
Α-Methylene aliphatic monocarboxylic acid esters such as dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, Acrylic esters such as propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl Vinyl ethers such as ethyl ether and vinyl isobutyl ether;
Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; methacryloyl Examples thereof include vinyl monomers such as acrylic acid or methacrylic acid derivatives such as nitrile and acrylamide.

In the present invention, the above-mentioned "other monomer"
When used, this monomer is preferably used in an amount of 30% by weight or less (further 20% by weight or less) based on the total amount of styrene and acrylonitrile monomers.

In the present invention, when the monomer composition is polymerized, the following cross-linking agent may be present to polymerize to form a cross-linked polymer.

As the crosslinking agent, divinylbenzene,
Divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1, 6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, propylene glycol dimethacrylate, 2,2 '
-Bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate,
Tetramethane tetraacrylate, dibromoneopentyl glycol dimethacrylate, diallyl phthalate, etc.
A general crosslinking agent can be used as appropriate.

For the organic fine particles according to the present invention, a copolymer obtained by polymerizing one or more of the above-mentioned "other monomer" or a crosslinking agent can be used.

The cross-linking agent is used in an amount of 0.0 based on the total amount of the monomers.
01 to 15% by weight, more preferably 0.1 to 10% by weight
It is preferable to use it in the amount used.

As the organic fine particles, those produced by a polymerization method are preferably used, and the shape thereof is preferably spherical. It is preferable that the organic fine particles have a spherical shape because the fluidity of the developer is not significantly deteriorated.

The organic fine particles have an average particle size (B).
Is smaller than the average particle diameter (A) of the colored fine particles, the average particle diameter of the organic fine particles is preferably 0.01 to 3 μm. If the particle size is smaller than 0.01 μm, it is difficult to exert the polishing effect, and if it is larger than 3 μm, the fluidity is deteriorated and the image quality is easily deteriorated. The ratio (B / A) of these average particle diameters is preferably 1/200 to 1/2. If B / A is less than 1/200, the polishing effect tends to be insufficient, and if B / A exceeds 1/2, the fluidity as a developer tends to be insufficient.

When the organic fine particles are negatively charged, the charge amount is preferably in the range of -40 to -100 μc / g. When the absolute value of the charge amount is smaller than −40 μc / g, the organic fine particles are easily separated from the colored fine particles, and the amount of −100 μc
If the absolute value is larger than / g, the image quality is easily fogged.

With respect to the amount of the organic fine particles used, it is preferable to mix 0.01 to 5.0 parts by weight, more preferably 0.1 to 5.0 parts by weight, with respect to 100 parts by weight of the colored fine particles composed of at least a binder resin and a colorant. It is preferable to mix 3 parts by weight. If the amount of the organic fine particles used is less than 0.01 part by weight, the polishing effect is difficult to obtain, and if it is more than 5 parts by weight, the fluidity is lowered and the image quality is apt to be lowered.

(Colored Fine Particles) In the present invention, fine particles containing at least a binder resin and a colorant are used as the colored fine particles.

The monomer composition of the binder resin which constitutes the colored fine particles is not particularly limited, and those generally used as the binder resin for toner (for example, the same monomers as those mentioned above for the organic fine particles are used). Stuff) can be used. In the present invention, it is preferable to use a copolymer of styrene and an acrylic acid ester or a methacrylic acid ester as the binder resin from the viewpoint of stable chargeability and prevention of desorption of organic fine particles based on the stability.

As the colorant, dyes and pigments are used, and those generally used as toner colorants can be used. In order to obtain good dispersion in the colored fine particles, a dispersion aid having a polar group introduced into a part of the polymer chain may be dyed and about half the amount of the pigment may be added for polymerization.

The colored fine particles contain at least a binder resin and a colorant as described above, but in addition, if necessary, for example, a charge control agent or an offset preventive agent composed of wax or polyethylene, polypropylene or other low molecular weight substance. Can be used (for example, internally added) if necessary.

The colored fine particles described above may be obtained by a polymerization method, a granulation method such as a spray drying method, or a pulverization method.

When colored fine particles are obtained by a polymerization method, fine particles polymerized by various polymerization methods can be used.
For example, emulsion polymerization, soap-free emulsion polymerization, suspension polymerization, etc. may be performed while maintaining the liquid monomer component in the form of droplets in a spherical state.

In the present invention, the polymer obtained by the above-mentioned polymerization method or solution polymerization, bulk polymerization, etc.
Colored fine particles may be obtained by granulating by a granulation method such as a spray drying method.

When colored fine particles are obtained by a pulverization method, for example, a usual toner formulation is blended, melted and mixed by a kneader,
After cooling, it may be roughly crushed, finely pulverized, and classified.

In the present invention, the average particle size of the colored fine particles is preferably 2 to 20 μm, more preferably 6 to 12 μm.

The colored fine particles produced by the above-mentioned methods such as the polymerization method, the granulation method and the pulverization method are preferably spheroidized by a mechanical or thermal treatment.

To make the shape spherical, (1) in order to increase the fluidity of the developer, (2) electrostatically develop the electrostatic latent image on the photoconductor onto the image holding material such as paper. In order to increase the transfer rate at the time of transfer (3), when it is used for a long period of time, the developer film is formed on the developing roller, the developing blade, and the photoreceptor by the adhesion of the developer. It is preferable from the viewpoint of obtaining a small amount of developer.

The degree of spheroidization of the colored fine particles is preferably 0.8 or more (more preferably 0.9 or more) in terms of sphericity as described later.

(External Additive) The developer of the present invention is composed of the colored fine particles and the organic fine particles as described above, but the developer of the present invention may contain silicone as another external additive, if necessary. It is preferable to mix fine silica particles that have been hydrophobized with oil or hexamethylene disilazane. These hydrophobizing agents are preferable because they improve the fluidity of the developer and do not adversely affect fog. The amount of the external additive used is preferably 2.0 parts by weight or less, more preferably 0.1 to 2.0 parts by weight, based on 100 parts by weight of the colored fine particles. If the amount used is less than 0.1 part by weight, the fluidity is not sufficiently improved, and if it is more than 2.0 parts by weight, fog tends to occur.

(Developing Method) The developer of the present invention is effective in both the two-component developing system and the magnetic one-component developing system, but the non-magnetic one-component developing system, that is, the layer thickness of the developer. The developing blade that regulates the pressure is arranged so as to come into pressure contact with the surface of the developing roll, the developer is evenly applied to the surface of the developing roll, and the developing roller is brought into direct contact with the electrostatic latent image on the photoconductor, or in a non-contact manner. In the developing method, it is particularly preferably used from the viewpoint of filming prevention.

An example of a developing device and a developing method in which the developer of the present invention can be used will be described with reference to FIG. As shown in FIG. 1, the developer 4 in the developer container 5 is
It is moved between the developing roll 2 and the developing blade 3 by the stirring rod 6, where the developer is forcibly thinned and charged.

The photoconductor 1 is precharged with the charger wire 9, and an optical signal or an optical image 10 is irradiated onto the photoconductor 1 to form an electrostatic latent image. Then, the photoconductor 1 is coated with the developer on the developing roll 2. Contact is made to develop the electrostatic latent image. Next, by using the transfer charger wire 11, the developed developer (visualized image made of the developer) on the photoreceptor is transferred to a support member 13 such as paper, and the developer is passed through a fixing roll 12 so that the developer is Are fixed on the support member 13.

The developer or toner on the photoconductor after transfer is removed by a blade method, a web method, a roll method or the like. The removed toner may be discarded or may be collected and reused.

As described above, the use of the developer of the present invention is particularly effective from the viewpoint of filming prevention in the system in which the developing roller is brought into direct contact with the electrostatic latent image on the photoreceptor to develop the film.

Further, the rubber-made developing blades that have been conventionally used may cause blurring or scraping, which is considered to be caused by deterioration or bleeding of low molecular weight oligomers, when used for a long period of time. It was. Recently, in consideration of this point, a developing blade made of metal has been increasingly used. When such a metal developing blade is used, the use of the developer of the present invention is particularly effective from the viewpoint of filming prevention.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The evaluation of the physical properties in the present invention was performed by the following methods.

(Fluidity) The fluidity of the developer was measured and evaluated using a powder tester device manufactured by Hosokawa Micron Co., Ltd. That is, a certain amount of developer is weighed, and 6
It was placed on a 0-mesh sieve, vibrated with a constant amplitude (scale of sliderac = 2.5) for 15 seconds, and the amount of toner passing through was converted into the weight per minute and displayed.

(Blow-off charge amount) The charge amount of the organic fine particles was measured by the following method. That is, Powder Tech Co., Ltd.
Carrier TEFV150 / 250, 59.7 g, and organic fine particles, 0.3 g, were weighed and put in a 200 cc SUS pot, and friction charged by rotating at 150 rpm for 30 minutes, using a Toshiba Chemical Co. blow-off meter.
The organic fine particles were blown off at a pressure of 1 kg / cm ² of nitrogen gas, and the charge amount was measured.

(Sphericality) In measuring the sphericity of the colored fine particles, several electron micrographs of the fine particles are taken to select the place where the whole volume of one powder is revealed, and the sphericity of the powder is determined. From the inside, the longest diameter (longest diameter) and the shortest diameter (shortest diameter)
Was selected and measured, 100 values obtained by dividing the minor axis by the major axis were determined, the average value of these values was determined, and this value was defined as the sphericity.

(Image characteristics) As a durability test, 20,000 sheets were printed using the developing device shown in FIG. 1, and the image density, the presence or absence of fog, and the presence or absence of toner film adhesion on the developing blade were visually observed and evaluated. .

The image density (ID) was evaluated by measuring the "black solid part" using a Macbeth reflection densitometer, and the image characteristics were evaluated in the following three stages.

(Image Density) O: High image density (Image density exceeds 1.3) Δ: Image density is slightly low (Image density = 1.1 to 1.3) X: Image density is low (Image Density less than 1.1) (Fog) ○: No fog △: Fogging is slightly observed ×: Fog occurs (Durability) ○: No blur after printing 20,000 sheets △: Little when printing 20,000 sheets Scratching x: Scratching in the middle of printing 20,000 sheets

Example 1 (Production of Colored Fine Particles by Polymerization Method) First, a dispersion aid used for producing colored fine particles was produced.

(Production of Dispersion Aid) A dispersion aid was produced by introducing a compound having a> C═N ⁺ <bond into a polymer having an unsaturated bond. Styrene / butadiene = 9
100 g of a styrene-butadiene random copolymer having a molecular weight of 0/10 and a MW of 50,000 was dissolved in 500 mL of benzene, placed in a reaction vessel equipped with a stirrer, a thermometer reflux condenser and a reagent inlet, and then stirred. While warming up to 60 ° C.

Benzylidenebutylamine (Ph-CH =
N-C ₄ and H _9), acetyl chloride (CH ₃ COC
0.1 mol each of 1) and tin tetrachloride were added to the above reaction vessel and reacted for 1 hour. After completion of the reaction, the reaction product was poured into 1 liter of methanol to completely solidify it. Next, this product was dried in a vacuum dryer to obtain a dispersion aid.

(Production of colored fine particles) 70 parts by weight of styrene, 30 parts by weight of butyl methacrylate, 4 parts by weight of the dispersion aid obtained above, 8 parts by weight of carbon black (Printex 150T, trade name, manufactured by Degussa), Cr Type dye (Bontron S-34, trade name, manufactured by Orient Chemical Industry Co., Ltd.) 0.5
By weight, 2 parts by weight of 2,2'-azobis (2,4-dimethylvaleronitrile) were dispersed in a ball mill at room temperature to obtain a uniform mixed solution.

Next, the above mixed solution is mixed with calcium phosphate 5
A dispersion was obtained by adding to 350 parts by weight of distilled water in which parts by weight were finely dispersed. The above-mentioned dispersion liquid was subjected to high-shear stirring by a rotor-stator type homomixer under conditions of pH 9 or higher, and the above-mentioned mixed liquid was atomized and dispersed in water.

Next, the aqueous dispersion of this monomer was put into a 1 L (liter) four-necked flask equipped with a stirrer, a thermometer, a nitrogen introduction tube, and a reflux condenser, and stirred at 65 ° C. for 4 hours. Was polymerized.

The polymer dispersion thus obtained was sufficiently washed with acid and washed with water, and then separated and dried to obtain a toner material as colored fine particles. The particle diameter of the obtained colored fine particles was 12.0 μm in volume average particle diameter, and the sphericity was 0.97.

(Production of Organic Fine Particles) 50 parts by weight of styrene monomer, 50 parts by weight of acrylonitrile, and 0.5 parts of divinylbenzene were placed in a 1 L four-necked flask equipped with a stirrer, a thermometer, a nitrogen introducing tube, and a reflux cooling tube. 4 parts by weight of distilled water, 200 parts by weight of distilled water, 0.6 parts by weight of potassium persulfate, 4 parts by weight of polyoxyethylene nonylphenol, and 1 part by weight of sodium lauryl sulfate, and put in a nitrogen stream at 80 ° C. for 4 hours.
Emulsion polymerization was performed for a time.

After completion of the polymerization, the reaction solution was cooled to 20 ° C., and the average particle size was 0.3 μm using an ultrafiltration device and a hot air dryer.
m spherical organic fine particles were obtained. The charge amount of the obtained organic fine particles was −96 μc / g.

(Production of Developer) 100 parts by weight of the colored fine particles obtained as described above, 0.3 parts by weight of the organic fine particles, and 0.3 parts of colloidal silica hydrophobized with silicone oil.
Parts by weight were added and mixed with a Henschel mixer to obtain a developer. The fluidity of the obtained developer was as good as 54 g / min.

(Evaluation) A commercially available non-magnetic single-component developing type laser beam printer shown in FIG. 1 (manufactured by Oki Electric Industry Co., Ltd.,
LP-800) was used and evaluated by incorporating the developer obtained above. Even after printing 20,000 sheets, the initial print quality was maintained and good results were obtained.

Example 2 Organic fine particles were obtained in the same manner as in Example 1 except that the styrene / acrylonitrile monomer composition was changed to 99% by weight of styrene and 1% by weight of acrylonitrile in the production of the organic fine particles of Example 1. It was The obtained organic fine particles had a particle diameter of 0.3 μm and a charge amount of −46 μc / g.

0.3 part by weight of these organic fine particles was used in Example 1
To 100 parts by weight of the colored fine particles obtained in step 3, along with 0.3 parts by weight of colloidal silica, a developer was obtained. The fluidity of the thus obtained developer was 64 g / min.
When this developer was evaluated in the same manner as in Example 1, the same good results as those in Example 1 were obtained.

Example 3 Similar to Example 1, except that the styrene / acrylonitrile monomer composition was 90% by weight of styrene and 10% by weight of acrylonitrile in the production of the organic fine particles of Example 1, and that divinylbenzene was not used. As a result, organic fine particles were obtained. The obtained organic fine particles had a particle size of 0.4 μm and a charge amount of −73 μc / g.

0.3 part by weight of the organic fine particles was used in Example 1
To 100 parts by weight of the colored fine particles obtained in step 3, along with 0.3 parts by weight of colloidal silica, a developer was obtained. The fluidity of the developer thus obtained was 58 g / min.
When this developer was evaluated in the same manner as in Example 1, the same good results as those in Example 1 were obtained.

Comparative Example 1 A developer was prepared and evaluated in the same manner as in Example 1 except that the organic fine particles were not mixed. As a result, the image density was reduced after printing 2000 sheets, the occurrence of blurring was observed, and the formation of a film due to the adhesion of the developer to the developing blade was observed.

Comparative Example 2 Organic fine particles were polymerized in the same manner as in Example 1 except that the styrene / acrylonitrile monomer composition was changed to 40% by weight of styrene and 60% by weight of acrylonitrile in the production of the organic fine particles of Example 1. Got

The particle size of the obtained organic fine particles is 0.3 μm.
The absolute value of the charge amount was -115 μc / g, which was high. 0.3 parts by weight of these organic fine particles were added to 100 parts by weight of the colored fine particles used in Example 1 together with 0.3 parts by weight of colloidal silica to prepare a developer. Liquidity at this time is 46
It was g / min. When the developer thus obtained was evaluated in the same manner as in Example 1, the fog which was a problem in practical use was initially generated.

Comparative Example 3 Organic fine particles were obtained by polymerizing in the same manner as in Example 1 except that acrylonitrile was not used in the production of the organic fine particles of Example 1 and the monomer composition was 100% by weight of styrene. The obtained organic fine particles have a particle size of 0.3 μm and a charge amount of −3.
The absolute value was as low as 3 μc / g.

0.5 part by weight of the organic fine particles was used in Example 1
To 100 parts by weight of the colored fine particles used in step 3, 0.3 parts by weight of colloidal silica was added to obtain a developer. The fluidity at this time was 44 g / min. When the developer thus obtained was evaluated in the same manner as in Example 1, there was no problem at the initial stage, but after printing 5,000 sheets, filming occurred on the developing blade and the image was blurred. When the developing roll was examined, organic fine particles were aggregated and separated from the colored fine particles.

The results obtained above are summarized in Table 1.

[0076]

[Table 1]

The abbreviations used in Table 1 above have the following meanings.
It is as follows. Abbreviations; ST: Styrene AN: Acrylonitrile BMA: Butyl Methacrylate DVB: Divinylbenzene

[0078]

As described above, according to the present invention, it is possible to prevent filming due to the developer on the photoconductor, the developing roller or the developing blade, and to prevent the reduction of the image density and the separation of the additive. An electrographic developer is provided.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a developing device and a developing method in which a non-magnetic one-component developer can be used.

[Explanation of symbols]

 1 Photoconductor 2 Development Roll 3 Development Blade (Rubber) 4 Developer 5 Developer Container 6 Stirring Bar 7 Cleaning Blade 8 Waste Toner Box 9 Charger Line 10 Optical Signal, Optical Image 11 Transfer Charger Line 12 Fixing Roll 13 Developer Support Material (paper etc.)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Hasegawa 1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa Inside the Zeon Corporation R & D Center (72) Inventor Jun Saito, Koichi Yozaki, Kawasaki-ku, Kawasaki-shi, Kanagawa 2-1-1 Nihon Zeon Co., Ltd. Research and Development Center

Claims (5)

[Claims] 1. 0.01 to 5 parts by weight of organic fine particles obtained by copolymerizing 50 to 99% by weight of styrene and 1 to 50% by weight of acrylonitrile with respect to 100 parts by weight of colored fine particles composed of at least a binder resin and a colorant. A developer obtained by mixing. 2. The colored fine particles have a spherical shape,
The developer according to claim 1, wherein the sphericity is 0.8 or more, and the charged fine particles have a negative charging property. 3. The organic fine particles are fine particles produced by a polymerization method, and the fine particles have a spherical shape and a particle diameter of 0.01.
The developer according to claim 1, which has a particle size of 3 μm. 4. The charge amount of the organic fine particles is −40 to −1.
The developer according to claim 1, wherein the developer is 00 μc / g. 5. A developing blade for controlling the layer thickness of the developer is arranged so as to be in pressure contact with the surface of the developing roll, the developer is uniformly applied to the surface of the developing roll, and the developing roll is formed on the electrostatic latent image on the photoreceptor. The developer according to claim 1, which is used in a method of developing by direct contact or confronting without contact.