JPS60186852A - Developer - Google Patents

Abstract

PURPOSE:To prevent decrease of image density and increase of fog by incorporating a toner powder and a fine acrylic/styrene including its deriv. copolymer powder having an average particle diameter smaller than that of this toner powder to prepare a developer. CONSTITUTION:A developer contains a mixture of a toner powder, e.g., having an average particle diameter of 3-20mum and a fine acrylic/styrene including its deriv. copolymer powder having that of 0.05-5mum, preferably, 0.1-2mum in an amt. of this fine powder of 0.01-10wt%, preferably, 0.05-2.0wt% of the toner. Said acrylic/styrene including its deriv. copolymer to be used for this fine powder is prepared by dissolving a copolymer obtained by the various polymn. processes, such as emulsion or suspension polymn. process, in a solvent, and granulating it by the spray drying process to form fine granules, or said fine powder is prepared also by mechanical pulverization.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developer, and particularly to a developer that prevents deterioration of developer properties.

Conventional technology A developing method applied to the inkstone photography method or the electrostatic recording method uses a developer consisting of toner and carrier, and applies a charge to the toner by frictional charging between the toner and the carrier. Methods for visualizing images are known. The visualized toner image on the photoreceptor or electrostatic recording material is transferred to transfer paper and fixed to form a copy, while the residual toner on the photoreceptor or electrostatic recording material that could not be transferred after transfer is transferred to the next transfer paper. It is cleaned in preparation for the copying process. This residual toner is cleaned by various methods such as a blade method, a brush method, and a web method, but as the copying process 8 continues thousands or tens of thousands of times, the toner that cannot be removed by these cleaning methods is removed. gradually accumulates on the surface of the photoreceptor, etc., resulting in inconveniences such as so-called poor cleaning or toner filming. In order to improve this phenomenon, for example, Japanese Patent Publication Nos. 48-8141 and 51
-1130, JP-A-50-120631, JP-A No. 52-
No. 84741 and the like propose a method of mixing additives into a developer composition. That is, Japanese Patent Publication No. 48-8141 discloses organic polymers with low surface energy such as polytetrafluoroethylene and polyvinylidene fluoride.
JP-A-50-120631 describes a non-adhesive polymer with a triboelectric charge series smaller than that of sulfur, and abrasives such as colloidal Kurimoto. Further, in Japanese Patent Application Laid-Open No. 52-84741, polystyrene particles are added to each developer to prevent poor cleaning or toner filming on the surface of a photoreceptor etc. due to a reduction in adhesion ability or a polishing effect. Although these methods are somewhat useful in preventing poor cleaning or toner filming,
Developers mixed with such additives have a problem that the ability to form a friction band on the toner is lower than that of developers without such additives.In other words, the image density decreases after the number of copies is 10,000 to 20,000 sheets. This results in an increase in fog and an increase in copying, which ultimately results in the inability to make copies.This phenomenon is particularly noticeable in high-temperature, high-humidity environments.At this time, no toner filming phenomenon occurs on the photoconductor, so this This phenomenon is thought to be due to a decrease in triboelectric charging ability.

Purpose of the Invention The present invention has been made in view of the above circumstances, and it is an object of the present invention to prevent poor cleaning or toner filming on a photoreceptor or electrostatic recording medium, and to prevent a decrease in image density and an increase in capri. The purpose of the present invention is to provide a developer that is

Structure of the Invention In order to achieve the above-mentioned object, the present inventors have conducted repeated research and developed a developer containing a toner powder and an acrylic/styrenic copolymer fine powder having an average particle size smaller than the average particle size of the toner powder. found that the agent gave significantly better results,
The invention has been completed. That is, it has been confirmed that by using the developer according to the present invention, complete smearing can be performed without damaging the latent image forming member, and that there is no adverse effect on the lifespan or deterioration of the developer.

The fine acrylic/styrene copolymer powder having an average particle size smaller than the average particle size of the toner powder used in the present invention can be one that has been polymerized using various polymerization methods. That is, emulsion polymerization, soap-free emulsion f
f polymerization,? In addition to polymers made into particles by suspension polymerization, fine powders obtained by dissolving polymers obtained by each of the above polymerization methods, solution polymerization, bulk polymerization, etc. in a solvent and then granulating them by spray drying, and mechanically pulverized polymers. A fine powder obtained by a method such as the above can be used.

The molecular weight of the acrylic/styrene copolymer used in the fine powder according to the present invention is not particularly limited, and a polymer having any molecular weight can be used without departing from the purpose of the present invention.

The glass transition temperature of the acrylic/styrenic copolymer used in the fine powder according to the present invention is preferably at least room temperature, but within the allowable range of toner fluidity and blocking property, the glass transition temperature is at or below room temperature. Polymers can be used.

Specific examples of monomers constituting the acrylic/styrene copolymer used in the fine powder according to the present invention include the following compounds.

That is, acrylic monomers include esters of acrylic acid, methacrylic acid, and alkyl alcohols, halogenated alkyl alcohols, alkoxyalkyl alcohols, aralgyl alcohols, and alkenyl alcohols. Specific examples of the above alcohols include methyl alcohol, ethyl alcohol, flobyl alcohol, phthyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, and hexadecyl alcohol. Alkyl alcohol: halogenated alkyl alcohol, which is partially halogenated alkyl alcohol; methoxyethyl alcohol, ethoxyethyl alcohol,
Alkoxyalkyl alcohols such as ethoxyethoxyethyl alcohol, methoxypropyl alcohol, and ethoxypropyl alcohol; benzyl alcohol, phenyl ether alcohol, phenylpropyl alcohol)
Alkyl alcohol; Examples include allyl alcohol and crotonyl alcohol.

In addition, styrene and its derivatives as styrenic monomers,
For example, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, flobylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, alkyl styrene, 70 rostyrene, chlorostyrene, bromostyrene, dipromostyrene, iodostyrene, dihalogenated styrene, dinitrostyrene,
Examples include acetylstyrene and methoxystyrene.

The monomers used in the preparation of the fine powder according to the present invention include one or more of the above acrylic monomers and one or more of the above styrene monomers, and if necessary, one or more other copolymerizable monomers. Alternatively, two or more types may be used. In this case, it is preferable that the total of the acrylic monomer and the styrene monomer account for at least 25% by weight of all monomers, and if possible, 50% by weight or more.

Specific examples of other monomers include the following compounds.

For example, addition polymerizable unsaturated carboxylic acids, namely acrylic acid, methacrylic acid, α-ethyl acrylic acid, crotonic acid,
Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as α-methylcrotonic acid, α-ethylcrotonic acid, incrotonic acid, teglic acid, ungelic acid, or maleic acid, fumaric acid, itaconic acid, citraconic acid, medicinal acid addition-polymerizable unsaturated aliphatic dicarboxylic acids such as acid, glutaconic acid, and dihydromuconic acid.

Furthermore, metal salts of these carboxylic acids can also be used, and this metal salt formation can be carried out after the completion of polymerization.

Further, esterification products of the above-mentioned addition-polymerizable unsaturated carboxylic acids and alcohols such as alkyl alcohols, halogenated alkyl alcohols, alkoxyalkyl alcohols, aralkyl alcohols, and alkenyl alcohols may be mentioned.

Furthermore, amides and nitriles derived from the addition-polymerizable unsaturated carboxylic acids; ethylene, propylene, butene,
Aliphatic monoolefins such as inbutylene; vinyl chloride, vinyl bromide, vinyl iodide, 1,2-dichloroethylene, 1,2-dibromoethylene, 1,2-short ethylene, isopropenyl chloride, isobromide 1. Rogenated aliphatic olefins such as propenyl, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, vinylidene fluoride;
, 3-butadiene, 1,3-pentadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,4-hexadiene, 3-methyl-2,4
Conjugated diene aliphatic diolefins such as -hexadiene can be mentioned.

Further examples include vinyl acetates, vinyl ethers, and nitrogen-containing vinyl compounds such as vinyl carbazole, vinyl pyridine, and vinyl pyrrolidone.

The aforementioned acrylic/styrene copolymer fine powder is amorphous,
Any shape such as spherical, flat, granular, etc. can be used, but a substantially spherical shape is particularly preferred.

This fine powder is mixed into the developer.

That is, the fine powder is first mixed with toner particles or carrier particles, and then this mixture is mixed into the developer, or the fine powder is directly mixed into the developer.

The use of the fine powder according to the present invention is not limited to only one type, but a plurality of types can be used in combination. The fine powder according to the present invention can be used in combination with other additives.

The average particle size of the fine powder according to the present invention needs to be smaller than the average particle size of the toner powder, but is preferably 0.05 to 5 μm.
A particle having a particle diameter of 0.1 to 2 μm, more preferably 0.1 to 2 μm, gives good results.

The amount of fine powder added according to the present invention is 0.01-
It can be used at 100% by weight, but more preferably 0% by weight.
．． 05-2.0% by weight gives good results.

The developer of the present invention is made by mixing a known toner in addition to the above-mentioned acryl/styrene copolymer, and the binder resin used in this toner includes styrene, chlorostyrene, and vinylstyrene. Styrene compounds such as ethylene, propylene, butylene, imbutylene, etc.: Monoolefins such as ethylene, propylene, butylene, imbutylene, etc.: Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc.; Methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid α-Methylene aliphatic monocarboxylic esters such as dodecyl, octyl acrylate, phenyl acrylate, methyl methacrylate, methacrylic ether, butyl methacrylate, dodecyl methacrylate; vinyl methyl ether, vinyl ethyl ether, vinyl phther ether, etc. Novinyl ether: Examples include homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone. Particularly typical binder resins include polystyrene, styrene, etc.
Examples include alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, and polypropylene.

Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin, and waxes.

In addition, toner coloring agents include carbon black, nidarosine dye, aniline blue, calcoyl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxiplate, and lamp black 1. , Rose Bengal, etc. can be exemplified as representative examples.

The binder resin and colorant are not limited to those exemplified above.

Furthermore, a magnetic toner containing a magnetic material can also be used.

The toner may have an average particle size of less than about 30 Ijrn, preferably from 3 to 20 μm.

The developer of the present invention mixed with the above-mentioned additives may be a so-called two-component developer having a carrier and a toner, or a so-called one-component developer not using a carrier.

When the developer to which the fine powder according to the present invention is added is a two-component developer, carriers that can be mixed with the developer have an average particle size that is approximately the same as the toner particle size or up to 500 μm. Various known particles such as iron, nickel, cobalt, iron oxide, ferrite, glass beads, granular silicon, and magnetic powder-dispersed resin particles are used.

Further, the surfaces of these particles may be coated with a coating agent such as a fluororesin, an acrylic resin, or a silicone resin.

The developer of the present invention can be used to develop an electrostatic latent image formed on a photoreceptor or an electrostatic recording medium. That is, an electrostatic latent image is electrophotographically formed on a photoreceptor made of an inorganic photoconductive material such as selenium, zinc oxide, cadmium sulfide, or amorphous silicon, or an organic photoconductive material such as a phthalocyanine pigment or a bisazo pigment, or an electrostatic latent image is formed on a photoreceptor made of an organic photoconductive material such as a phthalocyanine pigment or a bisazo pigment. A silent latent image is formed on an electrostatic recording medium having a dielectric material such as terephthalate using a needle-shaped electrode or the like, and the electrostatic latent image ζζ is formed by a developing method such as a magnetic brush method, a cascade method, or a touchdown method. A developer is applied to form a toner image. After this toner image is transferred to a transfer material such as paper, it is fixed and becomes a copy, and the toner remaining on the surface of the photoreceptor etc. is cleaned. As the cleaning method, various methods such as a blade method, a brush method, a web method, and a roll method can be used.

Effects of the Invention The effects obtained by the developer of the invention are as follows.

1. Poor cleaning can be prevented.

When cleaning the toner remaining on the photoreceptor, etc., the developer containing the fine powder of the present invention will not cause cleaning defects even if 50,000 copies are made.

On the other hand, developers using conventionally known additives can achieve sufficient cleaning in the initial stage, but the cleaning performance gradually decreases, and when the number of sheets exceeds 20,000 to 30,000, the image quality on the photoconductor is reduced. The toner remains on the paper, resulting in afterimages or black band-like streaks on the next copy.

2. The lifespan of the developer can be extended.

The developing ability of a developer, particularly the triboelectric charging ability, gradually decreases, and this decrease is particularly likely to occur in developers using conventional additives. However, the developer according to the present invention is less likely to cause a decrease in developing ability, and even after 50,000 copies are made, there is almost no decrease in the copied image density, even for originals with an image density of 0.7, which is particularly susceptible to the effect. do not have. Furthermore, it is not affected by high temperature and high humidity environments.

3. No damage to the photoreceptor and no toner filming.

The present invention will be explained in more detail below with reference to Examples and Comparative Examples, but the scope of the present invention is not limited in any way by the following Examples. All parts in each example are parts by weight.

Example 1 1t equipped with stirrer, thermometer, nitrogen introduction pipe, and U cooler
Put 80 parts of methyl methacrylate, 20 parts of styrene, and 300 parts of distilled water into the fourth flask, and add a redox catalyst consisting of potassium persulfate and sodium thiosulfate as a buffering agent at a concentration of 5 x 10-3 mole/L. The mixture was reacted for 2 hours at 60°C in a nitrogen stream, and then the liquid temperature was cooled to 20°C, and fine particles according to the present invention having an average particle size of 9.9 μm were separated using an ultrajet filtration device and a hot air dryer. Obtained.

Example 2 Into the same apparatus as in Example 1, 5 parts of methyl methacrylate,
Styrene 30 parts, distilled water 280 parts, potassium persulfate 0.
3 parts were added and polymerization was carried out for 24 hours at 70υ in a nitrogen stream. After the polymerization was completed, the reaction solution was cooled to 20° C., and fine particles according to the present invention having an average particle size of 0.5 μm were obtained using an ultra sieve device and a hot air dryer.

Example 3 A copolymer of styrene and n-butyl methacrylate was used as the binder resin, and carbon black was used as the colorant. 0.5 parts of the fine particles polymerized in Example 1 were added to 100 parts of toner with an average particle diameter of 12 μm. The mixture was mixed using a Hencourt mixer to obtain a toner for a developer according to the present invention.

Example 4 0.5 parts of the fine particles obtained in Example 3 were mixed with 100 parts of the same toner as in Example 3 using the same method as in Example 3 to obtain a developer toner according to the present invention. .

Comparative Example 1 A control toner was obtained by mixing 100 parts of the same toner as in Example 3 with 0.5 part of Boria, vinylide IJden fine powder using the same method as in Example 3.

Comparative Example 2 0.5 parts of zinc palmitate was mixed with 100 parts of the same toner as in Example 3 using the same method as in Example 3,
A control toner was obtained.

Comparative Example 3 The toner used in Example 3 was used as it was without adding fine polymer powder.

For a carrier made of spherical iron oxide powder with an experimental average particle size of 100 μm coated with styrene-methyl methacrylate copolymer,
The toners from Example 3 to Comparative Example 3 were mixed to prepare a developer. When a continuous copying test of 100,000 sheets was conducted using a Fuji Zero Bay 4370 copying machine, the results shown in the following table were obtained, demonstrating the effectiveness of the present invention.

Note 1) An original with an image density of 0.7, an image with an image density of 0.7 or higher
& density, and the number of copies that can be reproduced with a Capri density of 0.02 or less.

Claims (1)

[Claims] A developer comprising a toner powder and a fine acrylic/styrene copolymer powder having a semi-uniform particle diameter smaller than the average particle diameter of the toner powder.