JPH0322982B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrostatic image developing toner for heat roller fixation for developing electrostatic images formed in electrophotography, electrostatic printing, electrostatic recording, etc. be. [Prior Art] The process of developing an electrostatic image is a process in which charged fine particles are attracted by electrostatic attraction and adhered to the surface of an electrostatic image support, thereby visualizing the electrostatic image. Specific methods for carrying out such a development process include a wet development method using a liquid developer in which a pigment or dye is finely dispersed in an insulating organic liquid;
cascade method, which uses a powder developer consisting of a toner containing a colorant such as carbon black dispersed in a binder made of natural or synthetic resin;
There are dry developing methods such as the bristle brush method, magnetic brush method, impression method, and powder cloud method. The image visualized in the developing step may be fixed on the support as it is, but usually it is transferred to another support such as transfer paper and then fixed. In this way, the toner is not only subjected to the development process, but also to the subsequent processes, that is, the transfer process and the fixing process, so the toner has not only good developability but also the following processes: It is required to have good transfer and fixing properties. Among these, the conditions related to fixing properties are the most severe, and many studies and results have been published in the past on improving the fixing properties of this toner. It is generally advantageous to use a heat fixing method to fix the toner image formed in the developing process or the image to which this is transferred, and this heat fixing method includes the following steps:
There are non-contact heat fixing methods such as open fixing, and contact heat fixing methods such as heat roller fixing. The contact heating fixing method is excellent in that it has high thermal efficiency, and is particularly capable of high-speed fixing and is suitable for fixing in high-speed copying machines. Furthermore, since a relatively low-temperature heat source can be used, this method requires less power consumption, making it possible to make the copying machine smaller and save energy. Furthermore, there is no risk of fire even if paper remains in the fixing device, which is also preferable. Although the contact heating fixing method is preferable in various respects as described above, this method has a serious problem of occurrence of an offset phenomenon. This is a phenomenon in which a portion of the toner constituting the image is transferred to the surface of the heat roller during fixing, and this is transferred again to the transfer paper or the like that is fed next, staining the image.
In order to prevent this offset phenomenon, various proposals have been made and some have been put into practical use. One is to perform fixing while applying a release oil such as silicone oil to the surface of a heated roller, and the other is to provide the toner itself with offset prevention performance. The latter method is superior in that the structure of the fixing device is simple because a silicone oil application mechanism and the like are not required, and maintenance such as replenishment of silicone oil is not required. Therefore, the offset phenomenon occurs when the temperature of the heat roller increases, and therefore, the higher the minimum temperature at which the offset phenomenon occurs (hereinafter referred to as "offset occurrence temperature"), the better the non-offset property is. It can be called toner, but in order for toner to be fixed, it must be heated to a temperature above its softening point. Therefore, in an actual heat roller fixing device, the temperature of the heat roller is lower than that of the toner. The temperature is set at a specific temperature within the fixable temperature range, which is above the softening point and below the offset generation temperature. However, in reality, it is not possible to maintain the temperature of the heat roller completely uniformly at the set temperature, and there are other temperature-related considerations that must be taken into consideration. It is desirable to use a toner that does not impair the advantages of the heat fixing method. Generally, in order to raise the temperature at which offset occurs in a toner, it is effective to use a binder resin containing a high molecular weight component. Then, since the resin has a high softening point, the minimum temperature required for fixing the toner (hereinafter referred to as "minimum fixing temperature") becomes high.
The advantages of the contact heat fixing method are lost.
Naturally, it is desirable that this minimum fixing temperature be low, and in order to achieve the formation of visible images on both sides of a single sheet of transfer paper, which has recently become a high demand, the toner used for development must be It is necessary that the material can be fixed at a low temperature. In view of the above-mentioned background, a means has been developed for lowering the minimum fixing temperature by incorporating a low softening point wax made of a release agent such as polypropylene wax or polyethylene wax into toner particles. However, in this method, since the fluidity of the powdered toner is reduced, the developability and transferability are reduced, a good visible image cannot be formed, and there is a tendency for the toner to become cohesive.
Moreover, in order to obtain the effect of adding wax, the content ratio of the wax must be increased considerably, and as a result, wax components may adhere to the developing sleeve or electrostatic image support and form a film. , and there are drawbacks that impede its function. In order to improve the fluidity of toner, it is effective to add a fluidity improver made of fine hydrophobic silica powder to toner powder. In order to obtain this, it is necessary to add a large amount of hydrophobic silica fine powder, and as a result, the surface of the electrostatic image support is damaged by the highly hard hydrophobic silica fine powder, and the support is This becomes a serious problem when the electrostatic image support is a photoconductive photoreceptor, and when the surface of the electrostatic image support is cleaned with a rubber blade, the blade is subject to severe wear. In thermographic image forming apparatuses that have a recycling system in which toner that does not participate in the formation of toner images is returned to the developing device for reuse, fine particles of hydrophobic silica are embedded in the surface of the toner particles, and the toner The fluidity of the liquid decreases, and the resulting visible image becomes of low quality. Further, toners containing wax as described above usually include a polymer as a binder, a colorant, and a colorant.
It is produced by melt-kneading together with wax, a charge control agent and other toner components, and finely pulverizing the resulting agglomerates. In such a method,
Due to compatibility issues, the proportion of wax that can be included is limited, and even if a sufficient proportion of wax is included, it cannot be dispersed sufficiently uniformly in the toner particles, resulting in the wax being liberated on the surface of the toner particles. As a result, the fluidity of the toner is hindered. [Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its object is to provide a film having sufficient non-offset properties, a low minimum fixing temperature, and high fluidity and non-cohesiveness. An object of the present invention is to provide an electrostatic image developing toner for heat roller fixation, which can always form stable and good visible images. [Structure of the Invention] The toner for developing an electrostatic image for heat roller fixing of the present invention is characterized by having a softening point of 90 to 160°C as a result of block copolymerization with an aromatic vinyl monomer.
The polyethylene wax contains a polymer obtained by polymerizing a polymerizable monomer containing styrene in the presence of a polyethylene wax, and the ratio of the polyethylene wax to the polymerizable monomer is 1 to 20% by weight. ,
The ratio of the aromatic vinyl monomer in the polyethylene wax is 1 to 10% by weight, and the ratio of the weight average molecular weight to the number average molecular weight of the polymer is 3.5 or more and 15.6 or less. The present invention will be specifically explained below. In the present invention, a wax made of a polymer obtained by block copolymerizing an aromatic vinyl monomer and polyethylene, that is, polyethylene modified with an aromatic vinyl monomer (hereinafter referred to as "modified polyethylene"), and a polymerizable monomer A polymeric composition is obtained by mixing the polymerizable monomer with other toner components such as a colorant, or by dissolving or dispersing them in a common medium, and this polymeric composition is polymerized to form the polymerizable monomer. is polymerized in the presence of the wax to obtain a number average molecular weight of
The particle size ( Particles (usually 1 to 50 microns) are obtained to produce a toner for developing electrostatic images. Here, the content of the wax is within the range of 1 to 20% by weight based on the polymerizable monomer. If this proportion is less than 1% by weight, the effect of the wax as a release agent is not exhibited and the non-offset property of the toner is not improved, while if this proportion is too large, the fluidity of the toner may be reduced. As a result, developability and transferability deteriorate, and a good visible image cannot be formed, and the wax adheres to the developing sleeve or electrostatic image support to form a film.
This will impede its function. In the above, any polymerization method such as a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method, or a solution polymerization method can be appropriately used as a polymerization treatment method for the polymer composition, and in the polymerization method, a polymerization initiator or If a catalyst is required, it can be added to the polymerization composition. Alternatively, a polymer composition containing the wax but not a coloring agent or a charge control agent is prepared and polymerized, and a coloring agent or a charge control agent is added to the resulting wax-containing polymer and melt-kneaded. Alternatively, the resulting agglomerate may be pulverized. Furthermore, by appropriately selecting the polymerization method and its conditions, it is also possible to directly obtain a polymer having the desired particle size. In this case, the wax, colorant, charge control agent, and other toner components may be added to the polymer composition. By incorporating the necessary components, it is possible to obtain the desired toner, which is composed of spherical particles with high fluidity, in substantially one step. Suspension polymerization is generally used as the polymerization method in such cases. In this polymerization method, the polymer composition is dispersed and suspended in a dispersion medium such as water as dispersed particles of a desired particle size by mechanical stirring, and polymerization is carried out, but as the polymerization progresses, the dispersed particles become sticky. It is necessary to prevent them from coalescing into large particles by increasing the number of particles.
Suspension stabilizers are used for this purpose. The suspension stabilizers used as such suspension stabilizers are generally divided into water-soluble polymeric substances and fine powders of poorly soluble inorganic compounds.The former includes gelatin, starch, polyvinyl alcohol, and others, and the latter includes These include sparingly soluble salts such as barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, and calcium phosphate, inorganic polymer substances such as talc, clay, silicic acid, and diatomaceous earth, and powders of metal oxides and others. In addition, when the polymer composition contains an ionic substance, for example, a cationic substance or anionic substance such as a nitrogen-containing polymerizable monomer or poorly water-soluble amines,
If the dispersed particles are charged to one polarity, positive or negative, when dispersed in water, an ionic dispersant that is charged to the other polarity when dispersed in water, such as negatively charged colloidal silica. , positively charged aluminum oxide, etc. can be effectively used as suspension stabilizers. In addition, in this suspension polymerization method, stirring of the suspension system is an important element, and the conditions thereof affect the particle size of the polymer particles and the stability of polymerization. Although it depends on the viscosity and interfacial tension of the polymer composition, in order to obtain polymer particles with a particle size of 1 to 50 microns, shear stress of 10 ³
Stirring at ~ ¹⁰⁶ dynes/ ^cm2 is sufficient. As the polymerizable monomer that can be used in the present invention, a polymerizable monomer containing styrene as an essential component is used. Other polymerizable monomers that can be used with styrene include, for example, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p -n-butylstyrene, p-tert-butylstyrene, p-n
-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3, Styrene monomers such as 4-dichlorostyrene are preferred. In addition, for example, ethylenically 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, and vinyl benzoate. , vinyl esters such as vinyl butyrate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate , stearyl acrylate, acrylic acid 2
-Chlorethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethyl methacrylate α-methylene aliphatic monocarboxylic acid esters such as aminoethyl and diethylaminoethyl methacrylate; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. Vinyl ethers; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes, Others can be mentioned. These monomers can be used alone or in combination, or can be polymerized to form a copolymer. For the polymerization of vinyl monomers containing styrene as described above, a polymerization initiator is usually used in an amount of 0.5 to 10% by weight based on the polymerizable monomer. Specific examples of typical polymerization initiators include acetylcyclohexylsulfonyl peroxide, isodibutyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, 2,4-dichlorobenzoyl peroxide, t -butyl peroxybivalate, 3,5,5-trimethylhexanonyl peroxide, octanoyl peroxide,
Decanonyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, succinic acid peroxide, acetyl peroxide, t-butyl peroxy-2-ethylhexanoate, benzoyl peroxide, parachlorobenzoyl peroxide , t-butylperoxyisobutyrate, t-butylperoxymale acid, t-butylperoxylaurate, cyclohexanone peroxide, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-
2,5-dibenzoylperoxyhexane, t-
Butyl peroxy acetate, t-butyl peroxybenzoate, diisobutyl diperoxy phthalate, methyl ethyl ketone peroxide,
Dicumyl peroxide, 2,5-dimethyl-
2,5-di-t-butylperoxyhexane, t-
Butylcumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide,
2,5-dimethyl-2,5-di-t-butylperoxyhexane, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, pinane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, Peroxide initiators such as cumene hydroperoxide, 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-
carbonitrile), 2,2'-azobis4-methoxy-2,4-dimethylvaleronitrile, 2,2'-
Examples include azo initiators such as azobis-2,4-dimethylvaleronitrile. In addition, in order to obtain a polymer with a ratio Mw/Mn of 3.5 or more and 15.6 or less, (a) polymerization using a crosslinking agent, (b) using multiple polymerization initiators with different half-lives, Examples include (c) a method in which polymerization is carried out by mixing a high molecular weight polymer, (d) a method in which polymerization is carried out in the presence of a reactive prepolymer, and others. In addition, the molecular weight of the polymer is
This is determined from the gel permeation chromatogram. As the crosslinking agent used in the method (a) above, any known crosslinking agent can be used as long as it crosslinks and polymerizes the monomers according to the present invention. This crosslinking agent is preferably a compound having at least two polymerizable vinyl groups. Specifically, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane triacrylate, allyl methacrylate t-butylaminoethyl Diethylenically unsaturated carboxylic acid esters such as methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, etc., all divinyl compounds such as N,N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, etc. and a compound having three or more vinyl groups alone or two
More than one species is used in combination. Furthermore, ethylene glycol, triethylene glycol, 1,
2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,
4-bis(hydroxymethyl)cyclohexane,
Bisphenol-A, hydrogenated bisphenol-
A, polyoxyethylated bisphenol-A,
Dihydric alcohols such as polyoxypropylenated bisphenol-A; maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid,
Dibasic acids and their derivatives such as cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, their anhydrides or their esters with lower alcohols; trivalent or higher hydric acids such as glycerin, trimethylolpropane, pentaerythritol, etc. Alcohols and carboxylic acids having a valence of 3 or more, such as trimellitic acid and pyromellitic acid, are used as crosslinking agents in the present invention. The amount of such a crosslinking agent added to the monomer is selected in the range of 0.005 to 20% by weight, preferably 0.1 to 5% by weight. In the method (b) above, at a certain polymerization temperature, a polymerization initiator with a short half-life forms a so-called rapid initiation system, and a polymerization initiator with a long half-life forms a so-called slow initiation system. formed,
In the rapid initiation system, a polymer with a low degree of polymerization and a low molecular weight is formed, and at the same time, in the slow initiation system, a polymer with a high degree of polymerization and a high molecular weight is formed, so that the ratio Mw/Mn value is 15.6 or more than 3.5. The following polymers are obtained. Preferred examples of polymerization initiators with short half-lives include 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-
Examples include azobis-2,4-dimethylvaleronitrile, and preferred examples of polymerization initiators with a long half-life include 1,1'-azobis(cyclohexane-1-carbonitrile). . The prepolymers used in the method (d) above include butadiene polymer, α,ω-polybutadiene homopolymer, α,ω-polybutadiene glycol, α,ω-polybutadiene dicarboxylic acid, maleated polybutadiene, terminal acrylic-modified polybutadiene, terminal Preferred examples include polybutadiene prepolymers such as half-ester modified polybutadiene, and these can be used alone or in appropriate combinations. Such a reactive prepolymer may be contained in the polymer composition in an amount of 1 to 40% by weight, preferably 5 to 20% by weight, based on the polymerizable monomer. Of course, the methods (a) to (d) above may be used in combination. In the present invention, modified polyethylene, which is a wax present in the polymerization reaction system of a polymerizable monomer containing styrene, is composed of a polyethylene component and a modified component, and the polyethylene component is blocked by the modified component. Aromatic vinyl monomers are used as the modifying component, and specific examples thereof include 1-phenylpropene, styrene, o-methylstyrene,
m-methylstyrene, p-methylstyrene, α-
Methylstyrene, p-ethylstyrene, 2,4-
Dimethylstyrene, p-n-butylstyrene, p
-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-
Dodecylstyrene, p-methoxystyrene, p-
phenylstyrene, p-chlorostyrene, 3,4
-Dichlorostyrene, etc. can be mentioned. A wax made of modified polyethylene can be obtained by carrying out block copolymerization using the above-mentioned aromatic vinyl monomer and polyethylene according to conventional methods and conditions. For block copolymerization, a method using a living polymer or a method in which radicals generated by mechanochemically dividing the wax are reacted with an aromatic vinyl monomer to obtain a block copolymer can be used. Here, the proportion of the modified component in the modified polyethylene is within the range of 1 to 10% by weight.
If this ratio is too small, the fluidity of the toner will be significantly reduced, and if it is too large, the minimum fixing temperature of the toner will become high. It is also desirable that such modified ethylene itself has a low softening point, such as
It is required that the softening point is 90 to 160°C when measured by the ring and ball method specified in JISK2531-1960. The toner of the present invention contains a polymer obtained by polymerizing a polymerizable monomer containing styrene in the presence of a wax made of the above-mentioned modified polyethylene.
It is a granular material containing a coloring agent, a magnetic material, a property improving agent, and other necessary additives. Coloring agents include carbon black, nigrosine dye (CI No. 50415B), and aniline blue (CI No.
50405), Calco Oil Blue (CINo.azoec
Blue3), Chrome Yellow (CINo.14090), Ultramarine Blue (CINo.77103), DuPont Oil Red (CINo.26105), Quinoline Yellow (CI
No.47005), methylene blue chloride (CINo.
52015), Phthalocyanine Blue (CINo.74160),
Malachite Green Oxalate (CINo.
42000), lampblack (CI No. 77266), rose bengal (CI No. 45435), mixtures thereof, and others. These colorants need to be contained in a sufficient proportion to form a visible image of sufficient concentration, and are usually used in binder resins.
The proportion is about 1 to 20 parts by weight per 100 parts by weight. The magnetic material may be a ferromagnetic metal or alloy such as iron, cobalt, or nickel, including ferrite and magnetite, or a compound containing these elements, or a material that does not contain a ferromagnetic element but is subjected to appropriate heat treatment. Alloys that become ferromagnetic, such as manganese-copper-aluminum,
Mention may be made of a type of alloy called Heusler alloy containing manganese and copper, such as manganese-copper-tin, or chromium dioxide, among others. These magnetic substances are uniformly dispersed in the binder in the form of fine powder with an average particle size of 0.1 to 1 micron. The content is 20 to 70 parts by weight per 100 parts by weight of toner.
Preferably it is 40 to 70 parts by weight. The property improving agents include charge control agents, anti-offset agents, lubricants for improving fluidity, and others. The toner of the present invention is mixed with a carrier made of iron powder, glass beads, etc. to make a two-component developer, but when it contains a magnetic material, it can be used as is for developing electrostatic images as a one-component developer. . [Effects of the Invention] The toner according to the present invention has a ratio Mw/Mn of 3.5.
Since the above polymer having a molecular weight of 15.6 or less is used as a binder, the polymer is composed of a high molecular weight component and a low molecular weight component, and itself basically has a high offset generation temperature and a low minimum fixing temperature.
Moreover, the toner according to the present invention contains a wax made of not just polyethylene but modified polyethylene as described above, and furthermore, the wax contains a polymerization reaction system of a polymerizable monomer that provides a polymer as a binder. Since it is contained in the polymer by being present, as is clear from the explanation of the examples below, the ratio Mw/of the polymer of the binder is
Low-temperature fixing properties and non-offset properties that are even better than those obtained when the Mn value is 3.5 or more and 15.6 or less can be obtained, and even though the offset generation temperature is high, the minimum fixing temperature is low and Suitable for high-speed fixing using a roller fixing device. In addition, there is almost no reduction in fluidity due to the addition of wax, and in order to obtain the necessary fluidity, it is unnecessary or necessary to add a fluidity improver such as hydrophobic silica fine powder. However, it is sufficient to add only a small amount of the hydrophobic silica fine powder, and therefore, the adverse effects caused by adding a large amount of hydrophobic silica fine powder can be avoided. Furthermore, it has high non-aggregation properties and excellent storage stability. Therefore, according to the toner of the present invention, it is possible to achieve good development by having high fluidity and non-cohesiveness, and also to be able to fix at low temperature and high speed, resulting in high image density and Excellent visible images can always be stably formed. In addition, since the toner of the present invention has a low minimum fixing temperature, it is possible to avoid exposing the paper serving as the toner image support to high temperatures during fixing, and as a result, the occurrence of wrinkles is suppressed. It becomes practically possible to form a visible image using toner. The reason why the toner of the present invention has the above-mentioned excellent properties has not been strictly elucidated, but in addition to the binder having basically excellent properties, the offset occurrence temperature is low because the binder basically has excellent properties and the wax made of polyethylene is contained. The minimum fixing temperature decreases while the temperature remains high; the polyethylene is modified polyethylene and has a modified component in its molecular structure that has an affinity for the binder, and therefore has high compatibility with its own binder resin; In addition, compared to unmodified polyethylene wax, the modified component has lower stickiness and greater fluidity, and the modified polyethylene wax is produced by polymerization of the polymerizable monomer that produced the polymer, which is called a binder. Because it is contained by being present in the reaction system, it is in a uniform and stable state in the polymer, and therefore, the wax does not exist freely on the surface of the toner particles. This is believed to be because the fluidity of the toner does not deteriorate, and the content ratio of the wax in the toner can be increased, so that its excellent properties can be fully exhibited. When toner is produced directly by suspension polymerization, the resulting particles are essentially spherical, resulting in a toner with better fluidity than toner produced by a method that includes a pulverization process. It will be done. [Examples] Examples of the present invention will be described below, but the present invention is not limited thereto. Note that "parts" represent parts by weight. Example 1 Styrene 85 parts n-butyl acrylate 15 parts Ethylene glycol dimethacrylate 0.4 parts Carbon black "Mitsubishi Carbon Black MA"
-600'' (manufactured by Mitsubishi Kasei Corporation) 10 parts 2,2'-azobis-(2,4-dimethylvaleronitrile) 4 parts modified wax 3 parts The above modified wax is polyethylene wax block copolymerized with styrene (styrene The content of the components is 4% by weight, and the softening point is 112°C). The above substances were sufficiently mixed using a sand stirrer to prepare a polymerizable composition containing a polymerization initiator. This polymerizable composition was mixed with 3% by weight of calcium phosphate and 0.04% by weight of sodium dodecylbenzenesulfonate.
% by weight while stirring at a rotation speed of 9500 r.pm using a stirrer "TK Homogenizer" (manufactured by Tokushu Kogyo Co., Ltd.), and then stirring at a rotation speed of 100 r.pm using an ordinary stirrer. The obtained polymer was subjected to a polymerization reaction at a temperature of 60℃ for 7 hours, with Mw=160000, Mn=15000, Mw/Mn
= 10.7. After the polymerization reaction was completed, the reaction system was cooled, treated with dilute hydrochloric acid, dehydrated, washed and dried to produce a toner having an average particle size of 10 microns and a softening point of 140°C. This is referred to as "toner 1". Example 2 Styrene 80 parts n-butyl acrylate 20 parts Carbon black "Mitsubishi Carbon Black MA"
-600'' 10 parts 2,2'-azobis(2,4-dimethylvaleronitrile) 1.0 part 1,1'-azobis(cyclohexane-1-carbonitrile) 0.2 part Modified wax (same modified wax as in Example 1)
3 parts Using the above substances, the temperature was adjusted in the same manner as in Example 1.
Polymerization reaction at 80℃ for 7 hours resulted in Mw=140000, Mn
= 9000, Mw/Mn = 15.6, a toner with an average particle size of 10 microns and a softening point of 138°C was produced.
This will be referred to as "toner 2". Example 3 Styrene 70 parts Methyl methacrylate 20 parts n-butyl acrylate 10 parts Carbon black "#30" 10 parts α,ω-Polybutadiene glycol "NISSO
-PB-G-1000'' (manufactured by Nippon Soda Co., Ltd.) 10 parts azobisisobutyronitrile 4 parts modified wax (same modified wax as in Example 1)
3 parts Using the above substances, the temperature was adjusted in the same manner as in Example 1.
Polymerization reaction at 70℃ for 6 hours resulted in Mw=120000, Mn
= 16000, Mw/Mn = 7.5, a toner with an average particle size of 10 microns and a softening point of 137°C was produced.
This will be referred to as "toner 3." Example 4 In Example 1, the amount of modified wax used was changed to 10
The average particle size was 10% in the same manner as in Example 1 except that
Manufactured micron toner. This will be referred to as "toner 4." Example 5 Same as Example 1 except that polyethylene wax block copolymerized with 1-phenylpropene (1-phenylpropene content: 4% by weight, softening point: 113°C) was used as the modified wax. A toner with an average particle size of 10 microns was produced in the same manner. This will be referred to as "toner 5". Example 6 Instead of carbon black in Example 1,
A toner having an average particle size of 10 microns was produced in the same manner as in Example 1, except that 50 parts of triiron tetroxide powder "Mapiko Black BL-100" (manufactured by Titan Kogyo Co., Ltd.) was used. This will be referred to as "toner 6". Example 7 A polymer was obtained in the same manner as in Example 1 except that carbon black was excluded from the formulation in Example 1. 100 parts of this polymer and 10 parts of carbon black "Mogal L" were mixed and melted, kneaded, cooled, crushed and classified to obtain an average particle size of 10.
Manufactured micron toner. This is called "Toner 7". Comparative Example 1 A comparative toner having an average particle size of 10 microns was produced in the same manner as in Example 1 except that the modified wax was removed. This is referred to as "comparison toner 1." Comparative Example 2 The average particle size was obtained in the same manner as in Example 1, except that unmodified polyethylene wax "Hiwax 220P" (softening point 113°C, manufactured by Mitsui Petrochemicals) was used instead of the modified wax in Example 1. A comparative toner having a diameter of 10 microns was produced. This is referred to as "comparison toner 2." Comparative Example 3 A comparative toner having an average particle size of 10 microns was produced in the same manner as in Example 6 except that the modified wax was removed. This is referred to as "comparison toner 3." Comparative Example 4 The average particle size was obtained in the same manner as in Example 6 except that an unmodified polyethylene wax "Hiwax 220P" (softening point 113°C, manufactured by Mitsui Petrochemicals) was used instead of the modified wax in Example 6. A comparative toner having a diameter of 10 microns was produced. This is referred to as "comparison toner 4." Comparative example 5 Styrene 80 parts n-butyl acrylate 20 parts Carbon black "Mitsubishi Carbon Black MA
-600'' 10 parts 2,2'-azobis(2,4-dimethylvarenitrile) 3 parts modified wax (same modified wax as in Example 1)
3 parts Using the above substances, the temperature was adjusted in the same manner as in Example 1.
Polymerization reaction was carried out at 60℃ for 6 hours to obtain Mw=60000, Mn=
20000, average particle size by polymer with Mw/Mn=3.0
A toner with a diameter of 10 microns and a softening point of 135°C was produced.
This is referred to as "comparative toner 5." Comparative Example 6 A crosslinked polymer (Mw=
160000, Mn=15000, Mw/Mn=10.7) 100 parts carbon black "Mitsubishi Carbon Black MA
-600'' 10-part modified wax (same wax as in Example 1)
A comparative toner having an average particle size of 10 microns was produced by mixing 3 parts or more of the above substances and using a conventional toner production method including melting, kneading, cooling, pulverization, and classification steps. This is referred to as "comparison toner 6." Toner 1 to Toner 7 obtained as above
The fluidity of each of Comparative Toner 1 to Comparative Toner 6 was examined. In other words, by taking advantage of the fact that the more fluid the powder or granule is, the higher the quietness density is, the diameter 28
A sample was loosely packed into a 100 ml container with a 100 mesh sieve from above, and the weight was measured to determine the quietness density. In addition, each of a total of 10 toners other than Toner 6, Comparative Toner 3, and Comparative Toner 4 was mixed with a carrier made of iron powder coated with a resin film, and the toner concentration was 2% by weight, and the toner charge amount was We adjusted the developer to be 20±1 microcoulomb/g, and each of them produced an electrophotographic copying machine "U-Bix3000".
(manufactured by Konishiroku Photo Industry Co., Ltd.) to develop an electrostatic charge image,
The toner image is transferred to the transfer paper and the toner image is fixed by a heat roller fixing device, and the primary adhesion amount of toner to the photoreceptor drum surface, the transfer rate to the transfer paper, and the image density of the obtained copied image are measured. did. Here, the primary adhesion amount of toner is the so-called solid black potential.
This is the amount of toner adhered per unit area at 800V. Furthermore, the minimum fixing temperature and offset generation temperature were determined for each of the toners, and the storage stability was also evaluated. Regarding the lowest bonding temperature, a heat roller whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by Dupont) and a pressure roller whose surface layer is made of silicone rubber "KE-1300RTV" (manufactured by Shin-Etsu Chemical Co., Ltd.) A fixing device is used to fix the toner image of the sample toner transferred onto a 64 g/m ² transfer paper at a linear speed of 120 mm/sec, with the heat roller set at a temperature of 100°C.
Kimwipe rubbing is applied to the formed fixed image repeatedly at each temperature raised stepwise by 5°C, and the lowest set temperature for a fixed image that exhibits sufficient rubbing resistance is determined as the minimum fixing temperature. And so.
Note that the fixing device used here does not have a silicone oil supply mechanism. In addition, to measure the offset generation temperature, the toner image is transferred and fixed using the above-mentioned fixing device, and then a blank transfer paper is sent to the fixing device under the same conditions. The operation of observing whether or not toner stains occur was repeated while the set temperature of the heat roller of the fixing device was successively increased, and the temperature at which offset occurred was determined. Regarding storage stability, each sample was left for 48 hours at a temperature of 55°C and a relative humidity of 40%, and the presence or absence of aggregation and its degree were evaluated. The above results are shown in Table 1. In the table, the values marked with an asterisk (*) indicate that the offset phenomenon did not occur at that temperature.

[Table] Also, each of Toner 1 to Toner 5 and Toner 7 was used using an electrophotographic copying machine "U-Bix3000".
After conducting a continuous copying test over 20,000 times,
No matter which toner was used, a clear and good copy image was formed until the end. As is clear from the above results, the toner according to the present invention has excellent non-offset properties and has a very low minimum fixing temperature, compared to toners containing conventional unmodified polyolefin waxes. It has a wide range, has high fluidity and can be put to practical use even without the addition of fluidity improvers, has excellent developability and transferability, and always produces stable and good visible images. can be formed. Furthermore, as can be understood from the comparison between Example 1 and Comparative Example 6, in the case of a polymer containing modified wax by polymerizing monomers in the presence of modified wax, it is possible to incorporate modified wax by kneading. Greater fluidity was obtained than in the case of using a polymer with a polyurethane, and as understood from Example 4,
According to the present invention, a large amount of modified wax is contained in the toner, thereby making it possible to significantly lower the minimum fixing temperature while maintaining sufficient fluidity.

Claims (1)

[Scope of Claims] 1. A polymer obtained by polymerizing a polymerizable monomer containing styrene in the presence of a polyethylene wax having a softening point of 90 to 160°C, which is block copolymerized with an aromatic vinyl monomer. The ratio of the polyethylene wax to the polymerizable monomer is 1 to 20% by weight, the ratio of the aromatic vinyl monomer to the polyethylene wax is 1 to 10% by weight, and 1. A toner for developing electrostatic images for heat roller fixation, characterized in that the ratio of the weight average molecular weight to the number average molecular weight of the aggregate is 3.5 or more and 15.6 or less.