JPS5921024B2 - Developer for electrostatic images and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer for electrostatic images for hot roll fixing and a method for producing the same, and more particularly, the present invention relates to a developer for electrostatic images for hot roll fixing, and more specifically, a developer having a combination of fluidity and charging characteristics during development and offset resistance during fixing. This invention relates to an electrostatic image developer for heat roll fixing and a method for producing the same.

BACKGROUND ART Conventionally, a so-called magnetic brush method has been widely used as a developing method for developing an electrostatic latent image formed by electrostatic photography.

The developer used in this magnetic brush development method is a so-called two-component developer consisting of a blend of a powdered magnetic carrier such as iron powder and toner particles in which pigment is dispersed in a fixing medium, and a so-called two-component developer consisting of a powder magnetic carrier such as iron powder and toner particles in which pigments are dispersed in a fixing medium, and tetraoxide. A so-called one-component developer is generally used, which consists of conductive magnetic particles in which a fine powder of magnetic material such as iron is dispersed in a fixing resin together with other pigments if necessary, and the surface of which is subjected to conductive treatment if desired. There is. The toner particles or one-component developer particles applied on the electrostatic image are directly transferred to an electrostatic photographic photosensitive sheet or, if desired, transferred onto a transfer sheet and then fixed by a suitable heating means. For thermally fixing developer particles, the heat-pressing method using a roller is advantageous in terms of thermal efficiency, prevention of fire accidents, and speed of fixing operation, but the fixing roller surface and the image of the developer particles are heated and heated. Due to the contact under pressure, a so-called offset phenomenon occurs in which some of the developer particles adhere to and transfer to the surface of the fixing roller, and these particles transfer again onto the sheet to be fixed, causing stains on the photosensitive substrate and transfer sheet. It is known.

In order to prevent such defects, conventionally the surface of the fixing roller is made of a material with excellent mold releasability or stain resistance, such as fluororesin, and the surface is coated with an offset prevention liquid such as silicone oil. A method of forming a thin film is used, but this complicates the mechanism of the fixing device.
Another drawback is that it is difficult to supply offset prevention liquid in accordance with copying or printing operations accurately. In order to improve this drawback, a substance that acts as a release agent is pre-contained in the developer particles, and the substance is released in liquid form on the surface of the developer particles during fixation by a roller. Attempts have already been made to prevent the offset phenomenon. For example, Japanese Patent Publication No. 52-3304 discloses a toner for developing electrostatic images containing a colorant, a styrene resin, and a low molecular weight polypropylene. Such toner has the advantage that it is possible to perform an efficient and good fixing operation without causing the toner offset phenomenon by using a fixing roller that does not supply offset prevention liquid to the surface. The various properties during development are still not fully satisfactory. That is, in this type of toner, it is essential to liquefy and liberate the release agent substance on the surface of the toner particles during the fixing operation, and for this purpose, a relatively large amount of the release agent substance is contained in the toner particles. It is necessary to contain it.

Therefore, when toner particles contain a relatively large amount of release agent material, the fluidity and charging characteristics of the toner particles are significantly reduced. For example, most release agent substances are normally soft, and toner particles containing such release agents on their surfaces generally have a strong tendency to agglomerate. (The toner does not have sufficient fluidity to be evenly and uniformly applied on the sleeve surface, causing clumps on the sleeve surface, causing background stains due to toner particles falling off, and Due to uneven adhesion of toner particles on the surface, there is often a tendency for image force deviation to occur.Furthermore, the electrostatic image formed in commercial electrophotographic copying or printing operations is generally a negative charge image; Therefore, toner particles having a positive charge polarity are generally used.However, the release agent substance contained in a relatively large amount in the toner particles has a negative effect on the charge polarity. The present inventors have confirmed that many materials, such as the aforementioned polypropylene, act to reduce the positive charging characteristics. The disadvantage is that the toner image formed on the electrostatographic photosensitive substrate is transferred to the transfer sheet,
This phenomenon is more noticeable in electrostatographic copying methods in which this photosensitive substrate is repeatedly used.

That is, the release agent substance present on the surface of the toner particles is transferred to the surface of the photosensitive substrate and gradually accumulates to form an electrically insulating layer on the surface of the photosensitive substrate. Thus,
If such toner is used, even if the photosensitive substrate is used repeatedly a small number of times, residual charges will cause fogging of copies and electrical damage to the photosensitive substrate, significantly shortening the life of the photosensitive substrate. become. The inventors of the present invention have proposed that the developer composition contains a specific... The containing polymer (A) and the vinyl aromatic resin or acrylic resin fixing agent (B) having a lower melting temperature than the halogen-containing polymer are mixed in a specific dispersion form, that is, the fixing agent (B) is mixed into a continuous phase, When a developer with a fine structure containing the halogen-containing polymer (A) in the form of a dispersed particle phase is used, the offset phenomenon during fixing can be effectively eliminated, and the above-mentioned drawbacks observed in conventional developers can be avoided. I found that it was resolved all at once.

That is, in the present invention, the halogen-containing polymer (A) present in the form of a dispersed particle phase in the developer composition is
It is rather difficult to liquefy (melt) than B),
It is completely different in physical properties and functions from conventional mold release agent substances, and the fact that such a dispersed halogen-containing polymer has a function of preventing offset phenomenon is completely unknown to the knowledge of the present inventors. .

In addition, this halogen-containing polymer (A) is a polymer compound that is completely different from the mold release agent substance, and therefore has excellent fluidity during development according to the present invention, has little tendency to agglomerate, and has magnetic properties. It has the advantage that it has little tendency to contaminate electrophotographic photosensitive substrates that are used repeatedly and has excellent charging characteristics. According to the present invention, in an electrostatic image developer comprising particles in which a pigment is dispersed in a fixing medium,
The adhesion promoter comprises a thermoplastic or rubbery polymer (A) containing halogen atoms at a concentration of at least 100 milligram atoms/1007 polymer and a vinyl aromatic polymer having a lower melting temperature than the halogen-containing polymer. resin or acrylic resin fixing agent (B) in a weight ratio of A:B-1:20 to 1:1, and the halogen-containing polymer (A)
) is present in the form of dispersed particles dispersed in the continuous phase of the fixing agent (B), thereby providing an electrostatographic developer for heat roller fixing having excellent offset resistance.

The developer of the present invention can be used as a two-component developer, i.e., a developer consisting of toner particles used in combination with a carrier consisting of fine powder of magnetic material such as iron powder, or as a one-component developer, i.e., four-component developer. It can also be widely applied to developers in which fine powder of magnetic material such as iron oxide is pre-contained in particles.

In this specification, developer is a concept that includes these two-component and one-component developers, and toner particles refer to particles used in combination with a carrier to distinguish them from one-component developer. Please understand that this is a concept. The invention will be explained in detail below.

Developer Components An important feature of the present invention is that when a specific halogen-containing polymer is included in a specific dispersion form in combination with a specific fixing agent in the composition of a dry developer, it contains a release agent material. The offset phenomenon at the time of fixing is prevented by a function different from the conventional idea that the toner has an anti-offset property. This method is based on the new finding that the contamination tendency for photosensitive substrates is significantly improved.

About 10 halogen atoms as the halogen-containing polymer (A)
Any thermoplastic or rubbery polymer having a concentration of 0 milligram atoms/1007 polymer or greater, especially 300 to 4000 milligram atoms/1007 polymer or greater may be used.

When the concentration of halogen atoms is lower than the above range, satisfactory offset prevention properties cannot be obtained compared to the case of the present invention. As an example of the halogen-containing polymer (A),
Mention may be made of any polymer containing chlorine, fluorine, bromine, etc., in particular chlorine.

Suitable examples 11ζ Halogen-containing ethylenically unsaturated monomers such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, vinyl bromide, tetrafluoroethylene, chlorotrifluoroethylene, tetrachlorethylene, hexafluoropropylene, etc. Homopolymers and copolymers of these monomers and copolymers of other ethylenically unsaturated monomers; Homopolymers and copolymers of halogen-containing diolefin monomers such as 2-chlorobutadiene Coalescing or copolymers of these monomers with other ethylenically unsaturated monomers;
Examples include halides of hydrocarbon polymers or halogenated hydrocarbon polymers, and among these polymers, those satisfying the above-mentioned requirements can be used for the purpose of the present invention. More specifically, polyvinyl chloride, vinyl chloride copolymer, vinylidene chloride resin, vinyl chloride/vinylidene chloride copolymer, polyvinyl fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, chlorinated polyethylene, chlorinated Polypropylene, chlorinated polyvinyl chloride, chloroprene, chlorinated polyisobutylene,
Examples include tetrafluoroethylene/hexafluoropropylene copolymer.

Examples of monomers that can be copolymerized with the halogen-containing daughter ethylenically unsaturated monomer or diolefin monomer include vinyl esters such as vinyl acetate, vinyl formate, and vinyl propionate, acrylic acid, methacrylic acid, and maleic anhydride. acids, ethylenically unsaturated carboxylic acids such as fumaric acid, crotonic acid, itaconic acid; ethyl acrylate, methyl methacrylate,
Esters thereof such as 2-ethylhexyl acrylate and 3-hydroxyethyl acrylate; Amides thereof such as acrylamide and methacrylamide; Ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; N
- N-vinyl compounds such as vinylpyrrolidone, N-vinylindole, and N-vinylcarbazole; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketones and vinyl hexyl ketones such as vinyl methyl ketone and vinyl hexyl ketone. vinyl ketones such as; vinyl aromatic compounds such as styrene, α-methylstyrene, and vinyltoluene; ethylene, propylene,
Examples include olefins such as 4-methylbenzene; and diolefins such as butadiene and isoprene.

From the viewpoints of anti-offset properties, moldability into developer particles, stability of performance, etc., halogen-containing polymers that are particularly useful for the purpose of the present invention include copolymers of vinyl chloride and other monomers mentioned above. Or post-processed products (saponified, acetalized products)
Among them, vinyl chloride/vinyl acetate copolymer, partially or completely saponified vinyl chloride/vinyl acetate copolymer,
Saponified/acetalized vinyl chloride/vinyl acetate copolymer, vinyl chloride/vinyl acetate/maleic anhydride copolymer, vinyl chloride/vinyl acetate/acrylic ester copolymer, vinyl chloride/acrylonitrile copolymer, chloride These include vinyl/acrylic ester copolymer, vinyl chloride/acrylic ester/maleic acid copolymer, and the like.

The above-mentioned halogen-containing polymer (A) may be used alone or in combination of two or more.

In addition, for the purpose of improving its thermal stability, a p-stabilizer known per se, consisting of an inorganic acid salt, an organic acid salt, or an organometallic compound of calcium, magnesium, barium, zinc, cadmium, lead, or tin, is added per polymer. It can be used for the purpose of the present invention in an amount of 0.01 to 10% by weight. The molecular weight of the halogen-containing polymer (A) to be used is not particularly limited as long as it has a softening point of 180° C. or lower and generally has a molecular weight that allows film formation.

For example, in the case of vinyl chloride resins such as polyvinyl chloride and vinyl chloride monovinyl acetate copolymer, commercially available resins with an average degree of polymerization (15) in the range of 200 to 4000 are preferably used. Of course, even those with a lower or higher degree of polymerization can be used for the purpose of the present invention as long as they satisfy the above conditions. The above halogen-containing polymer (A) generally has a molecular weight of 60 to 170
It is preferable that the halogen-containing polymer (A
), it becomes possible to easily obtain a desired dispersion form in combination with the fixing agent (B) described below.

From the standpoint of preventing offset, the fixing agent (B) used in combination with the above-mentioned chlorogen-containing polymer (A) must have a lower melting temperature than the halogen-containing polymer (A). No.

That is, when a fixing agent having a melting temperature higher than that of the halogen-containing polymer (A) is used, it becomes difficult to obtain the dispersion form defined in the present invention, and satisfactory anti-offset properties cannot be obtained. In the present invention, a vinyl aromatic resin or an acrylic resin is used as the fixing agent (B).
As a vinyl aromatic resin, in the following formula, R1 is a hydrogen atom or lower (hereinafter lower means 4 carbon atoms).
(as used in the following meanings) is an alkyl group,
R2 is a lower alkyl group, a lower alkoxy group, a nitro group,
A substituent such as an amino group or a halogen atom, and n is O
or an integer of 1 to 2, such as styrene, α-methylstyrene, vinyltoluene (0-, m-,
Homopolymers and copolymers of p-methylstyrene), o-, m- or p-ethylstyrene, tert-butylstyrene, cyclohexylstyrene, phenylstyrene, methoxystyrene, chlorostyrene, nitrostyrene, aminostyrene, etc. Or it is a copolymer of these and other ethylenically unsaturated monomers.

Monomers that can be copolymerized with vinyl aromatic monomers include vinyl esters such as vinyl acetate, vinyl formate, and vinyl propionate; acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. ethylenically unsaturated carboxylic acids such as; ethyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, 3-acrylate
Its esters such as hydroxyethyl, its amides such as acrylamide and methacrylamide, ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; N-vinylpyrrolidone, N-vinylindole, N
- N-vinyl compounds such as vinyl carbazole; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl aromatic compounds such as styrene, α-methylstyrene, and vinyl toluene; ethylene , propylene, 4-methylbenzene, and diolefins; butadiene, isoprene, and other diolefins.

The vinyl aromatic copolymer mentioned above may be a so-called random copolymer, a block copolymer or a graft copolymer.

Examples of suitable copolymers are styrene/butadiene copolymers, vinyltoluene/butadiene copolymers, styrene/acrylic ester copolymers, vinyltoluene/acrylic ester copolymers, styrene/acrylic ester/
These include butadiene copolymer, vinyltoluene/acrylic acid ester/butadiene copolymer, styrene/ethylene copolymer, and the like. From the above-mentioned viewpoint, it is desirable that the vinyl aromatic resin used in the present invention contains vinyl aromatic units in an amount of at least 15 mol%, particularly 50 mol% or more.

Acrylic resins include homopolymers or copolymers of acrylic acid, acrino L ester, acrylamide, acrylonitrino, methacrylate, and methacrylic acid ester, preferably polyacrylic ester,
Examples include polymethacrylic ester, acrylic ester/methacrylic ester copolymer, acrylic ester/vinyl acetate copolymer, and the like.

The above-mentioned fixing agent resin (B) generally has a molecular weight of 500 to 150
00, particularly those with a relatively low molecular weight of 1,000 to 10,000 are desirable.

It is also particularly desirable for the purposes of the present invention that the melting temperature of the fixing agent resin (B) is at least 5° C., especially at least 10° C. lower than the melting temperature of the halogen-containing polymer (A). Furthermore, when selecting and combining the halogen-containing polymer (A) and the fixing agent (B), the melting temperature of the fixing agent (B) should be equal to or higher than the softening temperature of the halogen-containing polymer (A). It is particularly desirable to do so from the viewpoint of offset prevention. In the present invention, the halogen-containing polymer (A) and the fixing agent (B
) in a weight ratio of A:B-1:20 to 1:1, especially 1:10 to 1:2.

That is, if the amount of the halogen-containing polymer (A) is less than the above range, a satisfactory effect in terms of offset prevention cannot be obtained, while on the other hand, if the amount of the fixing agent (B) is less than the above range. In such cases, it becomes difficult to obtain the dispersion form specified in the present invention, and a satisfactory effect in terms of anti-offset property cannot be obtained, and furthermore, the fixing property of the developer itself tends to deteriorate. In the present invention, as the pigment, one type or a combination of two or more types of coloring pigments, extender pigments, magnetic pigments, and conductive pigments can be used.

These pigments may be pigments that have two or more of the above-mentioned functions; for example, carbon black has the function of a conductive pigment as well as a black pigment;
Triiron tetroxide functions not only as a magnetic pigment but also as a black pigment, as is clear from its name, so-called iron black. Suitable examples of colored pigments are:

Black pigment carpon black, acetylene black, lamp black, aniline black.

Yellow pigments yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, naples yellow, naphthol yellow, Hanser yellow G1
Visor Yellow-10G, Benzidine Ero-1 G1 Benzidine Ero-1 GRl Quinoline Yellow Lake, Permanent Ero-1 NCGl Tartrazine Lake.

Orange pigment red yellow lead, molybdenum orange, permanet orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RKl benzidine orange G, indanthrene brilliant orange GKO red pigment red pigment, cadmium red, red lead, mercury cadmium sulfide , Permanet Ret 4R1 Risol Ret - Pyrazolone Ret, Watching Ret Calcium Salt, Lake Ret D1 Brilliant Carmine 6B1 Eosin Lake, Rhodamine Lake B1 Alizarin Lake, Priliant Carmine 3B0 Purple Pigment Manganese Purple, Fast Violet B1 Methyl Bio Let's Lake.

Blue pigments navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated,
First Sky Bull 1, Indan Stramble 1 BCO
Green pigment chrome green, chromium oxide, pigment green B1
Malachite green lake, Huanal Yellow Green GO white pigment zinc white, titanium oxide, antimony white, zinc sulfide.

Extender pigment barite powder, barium carbonate, clay, silica,
White carbon, talc, alumina white.

As a magnetic material pigment, conventionally, for example, triiron tetroxide (Fe3
O4), iron sesquioxide (γ-Fe2O3), iron zinc oxide (
ZnFe2O4), iron yttrium oxide (Y3Fe,O
l2), iron cadmium oxide (CdFe2O4), iron gadolinium oxide (Gd3Fe5O,2), iron copper oxide (Cu
Fe2O4), iron lead oxide (PbFel2OlO), iron nickel oxide (NiFe2O4), iron neodymium oxide (N
dFeO3), barium iron oxide (BaFel2OlO)
, magnesium iron oxide (MgFe2O4), manganese iron oxide (MnFe2O4), lanthanum iron oxide (LaFeO
3), iron powder (Fe), cobalt powder (CO), nickel powder (Ni), etc. are known, but any of these known fine powders of magnetic materials can be used in the present invention. A particularly suitable magnetic material pigment for the purposes of the present invention is triiron tetroxide. As a conductive pigment! ζIn addition to the above-mentioned carbon black, any material such as inorganic fine powder or various metal powders which are non-conductive in themselves and which have been subjected to conductive treatment may be used.

The amount of pigment to be blended can vary widely depending on the use of the developer, and generally ranges from 1 to 300% by weight per fixer.

Within these ranges, for use as a toner in combination with a two-component developer, i.e., a magnetic carrier, it is recommended to use 1 to 15% by weight, especially 2 to 10% by weight, of color pigment per fixer. Often, for use as a one-component developer magnetically conductive developer, 50 to 300% by weight, especially 100 to 250% by weight of magnetic material pigment per fixer is used.
It is preferable to use it in combination with a colorant pigment or a conductive agent pigment if necessary. Other compounding agents known per se can be added to the developer of the present invention according to known formulations.
For example, charge control agents known per se as 4ζ for use as two-component developers, such as nigrosine base (CI5O4
15), oil-soluble dyes such as oil black (CI26l5O), spirone black, naphthenic acid metal salts, fatty acid metal soaps, resin acid soaps, etc., in an amount of 0.1 to 5% by weight per fixing agent. Can be done. The developer of the present invention is
A thermoplastic or rubbery polymer (A) containing halogen atoms at a concentration of 100 mg atoms/100'It polymer or more and a vinyl aromatic resin having a melting temperature lower than that of the halogen-containing polymer (A). Alternatively, a composition containing an acrylic resin fixing agent (B) in a weight ratio of A:B-1:20 to 1:1 and further containing a pigment (C) is used to soften the halogen-containing polymer (A). Kneading at a temperature higher than the melting temperature of the fixing agent (B) and lower than the melting temperature of the chlorogen-containing polymer (A); molding the kneaded composition into particles. Manufactured by.

That is, in order to produce a developer in the dispersed form defined in the present invention, the above-mentioned halogen-containing polymer (A) and fixing agent (
In addition to using combinations with B), these compositions can also be used in combinations above the softening temperature of the halogen-containing polymer (A) and the fixing agent (B).
) It is extremely important to knead at a temperature higher than the melting temperature of the halogen-containing polymer (A) and lower than the melting temperature of the halogen-containing polymer (A). By adopting such a kneading method, the continuous phase of the fixing agent (B) A composition in which the halogen-containing polymer (A) is finely dispersed is formed.

In an experiment different from the production method of the present invention, the halogen-containing polymer (A) and the fixing agent (B) were mixed without adding a pigment under normal crosstalk conditions, that is, at a temperature higher than the melting temperature of both. When kneading with The developer particles do not exhibit any offset prevention effect during roller fixing. On the other hand, when kneading the halogen-containing polymer (A) and the fixing agent (B) under the temperature conditions specified in the present invention, that is, at a temperature lower than the melting temperature of the halogen-containing polymer (A), A kneaded composition having a milky white appearance as a whole was obtained, and in this kneaded composition, it was observed that the behalogen-containing polymer (A) was finely dispersed in the fixing agent (B), and such a dispersion form was observed. The particles exhibit a significantly superior offset prevention effect.
The kneading operation can be carried out by means known per se, except for using the above-mentioned temperature conditions.

For example, a heat roll, mixer, kneader, etc. can be used as the device. The degree of kneading is not particularly limited, but generally the dispersed particle size of the halogen-containing polymer (A) is 3.
Any material that has a thickness of μ or less, particularly 0.5 μ or less may be used. To form developer particles from this kneaded composition, the kneaded composition is generally cooled to room temperature or a lower temperature, and then pulverized with a fine grinder such as a dinit mill, ball mill, roll mill, or vibration mill. The particles are sieved to obtain developer particles.

Instead of kneading under heat, each developer component is stirred in a high-speed stirrer such as a spur mixer under conditions that generate frictional heat, melting the fixing agent (B) and melting the halogen-containing polymer (A). It is also possible to obtain developer particles that are softened and unified.

Alternatively, instead of pulverizing the cooled material, a molten mixture of developer components can be directly formed into developer particles by means of spray granulation, centrifugal granulation, or the like.

The developer of the present invention can also be produced by the following alternative method.

According to this alternative method, a thermoplastic or rubbery polymer (A) containing halogen atoms at a concentration of 100 milligram atoms/100y polymer or more, and the halogen-containing polymer (A)
A vinyl aromatic polymer fixing agent (B) having a melting temperature lower than that of A:B' is dissolved or dispersed in an aromatic solvent at a weight ratio of 1:20 to 1:1, and then a pigment (C ) is sprayed into a dry atmosphere and dried to form particles.

That is, the vinyl aromatic polymer (B') serving as the fixing agent is extremely easily dissolved in aromatic solvents, whereas the halogen-containing polymer has poor solubility in aromatic solvents, and thus When both are dissolved in , a dispersion liquid is formed in which the fixing agent (B') becomes a continuous phase and the halogen-containing polymer (A) becomes a dispersed phase.

This fact is also confirmed by the fact that the dispersion exhibits a milky white color similar to that of an emulsion. Thus, when this dispersion is sprayed into a dry atmosphere and dried, a developer having the dispersion form similarly defined in the present invention can be obtained. As the aromatic solvent, benzene, toluene, xylene, tetrahydronaphthalene, ethylbenzene, or a mixed solvent thereof can be used. For the purpose of reducing the dispersion stability and particle size of halogen-containing polymers, aromatic solvents such as ketones such as acetone, methylethynoleketone, and methyl isobutyl ketone; and ethers such as tetrahydrofuran and dioxane are used. Polar solvents which are miscible with each other can be used in combination in an amount of up to 20%, in particular up to 10% by weight of the aromatic solvent. These organic solvents are preferably used in an amount of 1 to 50 times the weight of the fixing agent, and within this, the solid content concentration of the final stock solution containing the pigment should be in the range of 2 to 50% by weight. .

When spray drying this stock solution, heat the stock solution at a temperature of 5 to 100°C.
The stock solution is poured into a gas heated to a temperature of 50 to 150 °C, such as air, nitrogen, carbon dioxide, or combustion gas, using a one-fluid or two-fluid nozzle, a centrifugal spray nozzle, a rotary desk, etc. It is sprayed through a mechanism and formed into granules. Developer The developer of the present invention preferably has a number average particle size in the range of 2 to 80 microns (μ), particularly 5 to 50 μ, although it varies depending on the manufacturing method and the intended use. Among these, it is preferable to have a particle size distribution such that particles with a particle size of 50 μ or more account for 20% or less of the total, and particles with a particle size of 5 μ or less account for 15% or less of the total.

It is desirable that the developer particles have a substantially spherical shape, but this developer does not contain a so-called release agent material, but instead contains a high molecular weight halogen-containing polymer. A related advantage is that excellent fluidity and blocking resistance (non-agglomeration tendency) are maintained even if the material has an amorphous or angular granular morphology such as sand grains, crushed grains, or granules. There is.

The developer of the present invention can be subjected to various post-treatments depending on the intended use. For example, when used as a one-component developer, that is, a conductive magnetic developer, conductive fine particles (B) are attached to the surface of particles containing a magnetic material pigment (fixable magnetically sensitive particles A), and the necessary It is possible to impart good conductivity. Examples of the conductive fine particles (B) include various carbon blacks such as fanace black and channel black, among others, conductive black CO1Ox-L manufactured by Dexa Co., Ltd.
Vulcan Xc-72R manufactured by Gearpot Co., Ltd. is particularly desirable, but inorganic fine particles, metal powder, etc. treated with a conductive agent can also be used. These conductive fine particles (B) may be physically adsorbed and retained on the surfaces of the particles (A) by dry blending, for example, or may be actively embedded in the surfaces of the particles (A) by fusion or the like. The conductive fine particles (B) are 0.01 to 5% by weight, particularly 0.1% by weight, based on the particles (A).
It is preferable to use it in an amount of 2% to 2% by weight. The developer of the present invention can be widely used in applications for developing electrostatic images such as electrophotographic copying, electrostatic printing, and electrostatic recording.

The development of the electrostatic image can be carried out by development methods known per se, in particular by magnetic brush removal.

As is clear from the fact that the developer of the present invention generally has an angle of repose (tilt method) in the range of 10 to 70 degrees, particularly 30 to 60 degrees, it has extremely high fluidity, and in the following formula: XO is the weight (7) of the developer particles that passed through the 200 mesh sieve, and The agglomeration rate (Rc) defined by the weight (7) is 10% or less, particularly 5% or less, and is characterized by very little tendency for particles to aggregate with each other.

Thus, when the developer of the present invention is used, it is possible to effectively eliminate problems such as background contamination due to falling particles and image force deviation due to uneven adhesion of particles, and also to reduce the temperature in the developer storage section of the device. The agglomeration tendency of developer particles due to the rise can also be eliminated. When the developer of the present invention is used, an offset prevention effect can be obtained without using a so-called mold release agent, and it is also remarkable in terms of preventing staining of magnetic carriers and electrostatographic photosensitive substrates (masters). Benefits are achieved.

In known anti-offset toners containing release substances or lubricants, these substances gradually adhere to and accumulate on the magnetic carrier, causing deterioration of the magnetic carrier. Also,
Even in copying or printing methods in which toner particles or developer particles are transferred from a photosensitive substrate to a transfer sheet and the photosensitive substrate is used repeatedly, these substances gradually adhere to and accumulate on the photosensitive substrate, causing the various drawbacks mentioned above. arise. On the other hand, there is no fear that these release agent substances will be transferred to the developer Gζ carrier and the photosensitive substrate of the present invention and will be deposited and accumulated, making it possible to significantly extend the life of the carrier and the photosensitive substrate. . Furthermore, when release substances conventionally blended into toners are blended in amounts effective for preventing offset, they often have a negative effect on charge characteristics such as charge polarity and charge amount of toner particles, causing so-called fog and image damage. On the other hand, since the developer of the present invention does not use any of these releasing substances,
It also does not affect the charging characteristics of the developer particles.

The image of the developer particles formed by the development is fixed by a heat roller, either as is or after being transferred onto a transfer paper if necessary.

For heat fixing, a polytetrafluoroethylene coated roller equipped with an internal heating mechanism can be used, and heat fixing differs depending on the type of fixing agent, but generally 140
This is possible over a relatively wide temperature range from 200°C to 200°C. The reason why the developer of the present invention exhibits excellent anti-offset properties during fixing is still not fully clear. However, considering that a halogen-containing polymer existing in the form of a dispersed particle phase is effective in preventing offset, it is believed that such a granular halogen-containing polymer acts to repel the fixing roller due to the electronegativity of the halogen atoms. This is presumed to be due to the fact that the fixing agent (B) in a molten state is more strongly attracted to the particles of the rogen-containing polymer than to the fixing roller. The invention is illustrated by the following example.

Comparative Example 1 The developer for electrostatic development containing the rogen-containing polymer of the present invention is significantly superior in copying development characteristics compared to the developer containing a known release agent. is shown below.

(1) Comparative developer composition (a) Developer for electrostatic development of the present invention (b) Developer using a known release agent Vinyl chloride/vinyl acetate in the above developer of the present invention (a) A developer composition having the same composition as the composition of the present invention except that 12 parts of low molecular weight polypropylene (Viscol 550-P; manufactured by Sanyo Chemical Co., Ltd.) was used instead of 30 parts of the copolymer resin.

(c) Developer composition containing no release agent A developer composition that does not use the vinyl chloride V vinyl acetate copolymer in the developer composition of the present invention.

Each of the above compositions is mixed in advance, and this mixture is melt-kneaded in a three-roll hot roll mill at 150±5° C. for 25 minutes, and then the mixture is cooled to room temperature (10 to 20° C.) and solidified.

Subsequently, this kneaded material was roughly pulverized in a feather mill, then finely pulverized in a supersonic jet mill (manufactured by Nippon Neumatic Co., Ltd.; Type I jet mill), and a developer with a particle size distribution of 5 to 30 μ was obtained in a classifier. Ta. The copy development characteristics of each of the obtained developers were compared using the following measuring method. (2) Measurement method O Offset resistance sample developer 50f and carrier iron powder (manufactured by Nippon Iron Powder Co., Ltd.: EF
■ After uniformly mixing 950 tons of 200 to 300 tons, put it into a developer bottle of an electrostatic copying machine manufactured by Sanda Kogyo Co., Ltd. (built-in heat fixing roller coated with tetrafluoroethylene resin).
A document containing an image was copied at a fixing temperature of 180° C.±3° C., and the staining state of the fixing roller and the offset state of the image on the copy were visually observed and compared.

O Developer fluidity (angle of repose) * When a sample developer is filled into a glass cylindrical container (capacity 600y), the free surface is leveled, and the container is tilted, the developer particles on the surface begin to slide. The inclination angle was measured using a protractor and compared.

Accurately collect 30 f7 of the O-cohesive sample developer, sieve it through a 200-mesh sieve, accurately measure the weight of the developer that has passed through the 200-mesh sieve, and then place the passed material into a glass sample container (
After heating and drying in a dryer at 50°C for 60 minutes, the developer was sieved again through a 200-mesh sieve, and the weight of the developer remaining on the 200-mesh sieve was measured to determine whether each developer was agglomerated. compared gender.

0 Continuous copyability (stains on master and fog on copies)
Sample developer 507 and carrier iron powder (EF manufactured by Nippon Tetsuko Co., Ltd.)
■ After uniformly mixing 200~300) 950y to use as a starting agent, put it into the developing bottle of an electrostatic copying machine model 251 manufactured by Sanda Kogyo Co., Ltd. (built-in heat fixing roller coated with tetrafluoroethylene resin), and print the image. Continuous copying was carried out at a fixing temperature of 180° C.±3° C. using a manuscript containing the original material, and after each copying of a certain number of sheets, the copying was stopped, and the staining state of the master, the fogging state of the copies, and the replenishment state of the developer were visually observed and compared.

1) To replenish the developer, an appropriate amount of the developer was replenished into the replenishment vat, and the developer was continuously replenished.

Results: As shown in Table 1 below.

As is clear from the above results, it is clear that the developer for electrostatic development of the present invention is significantly superior to conventional developers in its copy development properties.

Comparative Example 2 The following experiment was conducted to demonstrate that the halogen atom content of the halogen-containing polymer of the present invention must be 100 W atoms/1007 or more.

As a developer composition for comparative experiments, each of the above compositions was mixed appropriately, and a three-roll hot roll mill (1
Knead and disperse uniformly for 25 minutes at 50±5℃) and leave at room temperature (1
After sufficiently cooling at 0 to 20°C), it was roughly pulverized using a feather mill (manufactured by Hosokawa Iron Works Co., Ltd.), and then finely pulverized using a supersonic jet mill (type I jet mill; manufactured by Nippon Two-Yumatic Co., Ltd.), and then classified. 5-30μ developer N. B'
, C', D5, E(F(G and w were obtained.

For each developer obtained, iron powder (carrier;
Nippon Iron Powder Co., Ltd.; EFV 200-300) (at a ratio of 950y of iron powder to 50f7 of developer), and then filled into a fixing tester made by Sanda Kogyo Co., Ltd. equipped with a built-in Teflon roller for heat fixing, and then fixed. Copied images were prepared at a temperature of 180° C.±5° C., and the fixing properties and offset development of the developer onto the Teflon roller were compared. Measuring method O Fixability: The image area of the obtained copy was rubbed 50 times using a rubbing fastness tester (crokmeter), and the fixability was visually observed and compared.

Offset property to O fixing roller: Performed in exactly the same manner as in Comparative Example 1. Results: Table 2 below shows the results.

Comparative Example 3 The following experiment was conducted to demonstrate that there is a limit to the amount of the halogen-containing polymer of the present invention used in the fixing resin.

As a developer composition for comparative experiments ― 3.

The above composition was prepared in exactly the same manner as in Comparative Example 1 to obtain developers a'', b'', c', d'', e'' and f''.

Each of the obtained developers was compared using the same measuring method as in Comparative Examples 1 and 2, and the glossiness of the images of the obtained copies was also visually observed. Results: As shown in Table 4.

The above results show that halogen polymers are flexible by their own nature, but because they are firmly fixed, they are difficult to crush, making it difficult to obtain the optimum particle size as a developer, and causing gloss in copied images. If the amount used is small, the offset prevention effect will be lost.

Comparative Example 4 A developer for electrostatic development containing the halogen-containing polymer of the present invention lζ The morphology of the particle surface changes depending on the manufacturing conditions, and this changes the adhesion state of the developer to the fixing roller and the copying process. The following experiment was conducted to demonstrate the difference in fixability to sheets.

o Comparative experimental developer composition (1) Composition for hot roll mill production The above compositions were mixed appropriately, and the heating conditions of three hot rolls were set to 110±5°C, 150±5°C and 190±5°C. After kneading each mixture at a temperature for 25 minutes and uniformly dispersing the mixture, a comparative developer was prepared using the same pulverization method as in Comparative Example 1 for each of the kneaded products.

Separately, the above composition was placed in a three-roll hot roll mill, and kneaded at a heating temperature of 150°C ± 5°C for 3 minutes, 5 minutes, and 10120 minutes.
After kneading for 30 minutes and 30 minutes, the mixture was pulverized in the same manner as above to prepare a comparative developer. 2) Composition for spray granulation o Composition (■); (Halogen polymer solution) The amount of methyl ethyl ketone used in the above composition (1) was 400 parts,
Composition (1) except that the amount of toluene used was 400 parts
The composition is exactly the same.

Each of Doki compositions (1) and (■) was placed separately in a KVM dispersion machine and uniformly dispersed for about 30 minutes at a liquid temperature of 30 to 50°C. Air pressure 2.5kg/cr! 11 Spray granulation was performed using a spray nozzle diameter of 1671L1Lφ, and developer particles (1
'') and (■') were obtained. The obtained developer particles were classified into particle diameters of 5 to 30 μm using a classifier, and used as a comparative developer.

The fixing properties and offset properties to the fixing roller of the developers obtained by the methods (1) and (2) above were measured and compared using the same measuring method as in Comparative Examples 1 and 2.

Results: As shown in Table-5. From the above Q results, it is certain that the dispersion form of the halogen-containing polymer in the developer changes due to changes in the kneading temperature and kneading time depending on the kneading means, and that the copying characteristics of the developer differ significantly. The kneading temperature must be lower than the melting temperature of the halogen-containing polymer, and the kneading time must be sufficient to uniformly disperse the halogen-containing polymer.

Furthermore, in the spray granulation method, it is necessary to not completely dissolve the halogen-containing polymer, but to uniformly disperse it in a milky white dispersion state before spray granulation. Example 1 After melt-mixing a mixture having the above composition at 150°C in a heated roll mill and kneading it uniformly, the kneaded product was heated at room temperature (10 to
The developer was solidified by cooling to a temperature of 20° C.) and then pulverized using a jet mill to obtain a developer having an average particle size of about 5 to 30 μm.

This obtained developer was used in electronic copister 25 manufactured by Sanda Kogyo Co., Ltd.
As a result of copying with a 1R copying machine (equipped with a Teflon-coated heat fixing roller), a clear image was obtained with no stains on the heat fixing roller surface and no offset development. This operation was continued and even after 1000 copies were made, clear images were obtained with no stains on the fixing roller or occurrence of offset phenomenon. Example 2 A developer was obtained from a mixture having the above composition as a two-component electrostatic image developer composition in the same manner as in Example 1.

The obtained developer was copied using an electronic copier 251R copying machine, and the same results as in Example 1 were obtained. Example 3 A mixture having the above composition was subjected to the same operations as in Example 1 to obtain a developer as a two-component electrostatic image developer composition.

The obtained developer was copied using an electronic copier 251R copying machine, and as a result, the same results as in Example 1 were obtained.
Example 4 A mixture having the above composition as a two-component electrostatic image developer composition was melted and mixed at 160° C. in a heated Nigga oven to uniformly dissolve and disperse, and then the dispersion was heated at room temperature (
After solidifying by cooling to 10 to 20[deg.] C.), the developer was pulverized in a dinit mill to obtain a developer having an average particle size of about 5 to 30 microns.

This obtained developer was used in an electronic copister 125 manufactured by Sanda Kogyo Co., Ltd.
As a result of copying with a 1R copying machine, there was no dirt on the heat fixing roller, and a clear image without any offset phenomenon was obtained. Furthermore, even if this operation was continued, exactly the same results were obtained. Example 5 A mixture having the above composition as a two-component electrostatic image developer composition was dissolved and dispersed in a ball mill for 24 hours, and then this dispersion was spray-dried (drying temperature: 15
A developer having an average particle size of about 5 to 30 microns was obtained by spray drying at 0°C.

When the obtained developer was copied using an electronic copier 251R copying machine, a clear image was obtained with no stains on the heat fixing roller and no offset phenomenon. Furthermore, even if this operation was continued, exactly the same results were obtained. Example 6 As a two-component electrostatic image developer composition, a mixture having the above composition was subjected to the same operation as in Example 5 to obtain a developer.

The obtained developer was copied using an electronic copier 251R copying machine, and the same results as in Example 5 were obtained. Example 7 = Component-based electrostatic image developer composition A mixture having the above composition was melt-mixed at 150° C. using a hot roll and kneaded uniformly.

This composition was cooled and further cooled to room temperature (10 to 2'C), and then ground in a pin mill type grinder to obtain powder image particles of 5 to 50 microns. This powder image particle is sent to Sanda Kogyo Co., Ltd.
As a result of copying with a copying machine manufactured by Electronic Copystar 700D (using a Teflon-coated heat fixing roller), there was no dirt on the surface of the heat fixing roller, and clear copies with no offset phenomenon were obtained. Even after repeated continuous copying of 1,000 sheets, clear images were obtained with no stains on the fixing roller or any offset phenomenon. Example 8 As a composition for a one-component electrostatic image developer, a mixture having the above composition was melt-mixed at 160° C. in a kakun-dama and uniformly kneaded.

This composition was cooled, further cooled to room temperature (10 to 20°C), and then ground in a pin mill type grinder to obtain a developer having a diameter of 5 to 50 microns. Use this developer with Electronic Copystar 70.
As a result of copying with 0D (using a Teflon coated heat fixing roller), a clear copy was obtained with no dirt on the surface of the heat fixing roller and no offset phenomenon. Example 9 As a composition for a one-component electrostatic image developer, a mixture having the above composition was stirred with an attritor to uniformly dissolve and disperse the mixture.

Spray this dispersion using a dryer (hot air temperature: 150°C).
The particles obtained by spray drying were classified to obtain a developer having a size of 5 to 50 microns. After developing an electrostatic image formed by ordinary electrophotography using this developer, the powder image was transferred to transfer paper and fixed using a Teflon-coated heat fixing roller. A clear image with no surface stains and no offset phenomenon was obtained. Example
10 A developer of 5 to 50 microns was obtained in the same manner as in Example 13, except that the Q inhibitor was not used as a composition for a one-component electrostatic image developer.

When this developer was copied using an electronic copier 700D copying machine (using a silicone rubber-treated heat fixing roller), a clear image was obtained with no stains on the heat fixing roller and no offset phenomenon. Example 11 As a composition of a one-component electrostatic image developer, the above Q composition was prepared in the same manner as in Example 13 to obtain a 5 to 50%
A micron developer was obtained.

Claims (1)

[Scope of Claims] 1. A one-component developer for electrostatic images consisting of particles in which magnetic material pigments are dispersed in a fixing medium, wherein the fixing medium contains halogen atoms of 100 milligram atoms/100 g of polymer or more. a thermoplastic or rubber-like polymer (A) containing at a concentration of , and a vinyl aromatic resin or acrylic resin fixing agent (B) having a lower melting temperature than the halogen-containing polymer.
and A:B in a weight ratio of 1:20 to 1:1, and the halogen-containing polymer (A) is a fixing agent (B).
A developer for electrostatic images for hot roll fixing, which has excellent anti-offset properties and is characterized by being present in the form of dispersed particles dispersed in a continuous phase. 2. The developer according to claim 1, wherein the halogen-containing polymer (A) is a chlorine-containing polymer. 3. The developer according to claim 1, wherein the halogen-containing polymer (A) is a vinyl chloride homopolymer or copolymer. 4. The developer according to claim 1, wherein the halogen-containing polymer (A) is a vinyl chloride/vinyl acetate copolymer or a vinyl chloride/vinyl acetate/ethylenically unsaturated carboxylic acid copolymer. 5 The melting temperature of the fixing agent (B) is higher than that of the halogen-containing polymer (A
) The developer according to claim 1, wherein the temperature is higher than the softening temperature of the developer. 6. The developer according to claim 1, which contains a magnetic material pigment in an amount of 50 to 300% by weight based on the fixing medium. 7 Magnetic material pigment is 100 to 250% by weight per fixer
A developer according to claim 1, wherein the developer is present in an amount of . 8. A two-component developer for electrostatic images comprising particles in which colored pigments are dispersed in a fixing medium and a magnetic carrier,
The fixing agent medium comprises a thermoplastic or rubbery polymer (A) containing halogen atoms at a concentration of 100 milligram atoms/100 g polymer or more and a vinyl aromatic resin having a lower melting temperature than the halogen-containing polymer. or an acrylic resin fixing agent (B) in a weight ratio of A:B=1:20 to 1:1, and the halogen-containing polymer (A) is contained in the continuous phase of the fixing agent (B). A developer for electrostatic images for hot roll fixing that has excellent offset resistance and is characterized by being present in the form of dispersed particles. 9. A developer according to claim 8, wherein the colored pigment is present in an amount of 1 to 15% by weight per fixer. 10 100 milligram atoms/100g of halogen atoms
A thermoplastic or rubbery polymer (A) contained in a concentration higher than that of the polymer and a vinyl aromatic resin or acrylic resin fixing agent (B) having a lower melting temperature than the halogen-containing polymer (A). A composition containing A:B in a weight ratio of 1:20 to 1:1 and further containing a pigment (C) is heated to a temperature equal to or higher than the softening temperature of the halogen-containing polymer (A) and of the fixing agent (B). above the melting temperature and the halogen-containing polymer (
A method for producing an electrostatic image developer for hot roll fixing, which comprises kneading at a temperature lower than the melting temperature of A); forming the kneaded composition into developer particles, and optionally classifying the composition. 11 100 milligram atoms/100g of halogen atoms
A thermoplastic or rubbery polymer (A) contained at a temperature higher than that of the polymer, and a fixing agent (B) of a vinyl aromatic polymer having a lower melting temperature than the halogen-containing polymer (A). A composition prepared by dissolving or dispersing in an aromatic solvent at a weight ratio of A:B = 1:20 to 1:1 and further dispersing the pigment (C) is sprayed into a dry atmosphere and dried to form particles. A method for producing an electrostatic image developer for hot roll fixing, characterized by: