JP2012181241A - Toner and manufacturing method of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner which contains rosin originated from biomass, and in which charging amount of the toner is constant even when carbon black is used as a coloring agent, and scattering of toner and fogging are reduced, and to provide a manufacturing method of the toner.SOLUTION: The toner includes a binder resin containing 60 to 75 wt.% of disproportionate rosin as a monomer component, carbon black, and a reaction component of the disproportionate rosin and polyalcohol.

Description

  The present invention relates to a toner and a method for producing the toner.

  The toner that visualizes the latent image is used in various image forming processes, for example, an electrophotographic image forming process.

  In an image forming apparatus using an electrophotographic image forming process, generally, a charging process, an exposure process, a developing process, a transfer process, a fixing process, and a cleaning process are performed to form a desired image on a recording medium. To do.

  In the charging step, the photosensitive layer on the surface of the photosensitive drum, which is a latent image carrier, is uniformly charged. In the exposure step, the electrostatic latent image is formed by projecting the signal light of the original image onto the surface of the charged photosensitive drum. In the developing step, the toner is agitated and charged, and the charged toner is supplied to the surface of the photosensitive drum to visualize the electrostatic latent image. In the transfer step, the toner image on the surface of the photosensitive drum is transferred to a recording medium such as paper or an OHP sheet. In the fixing step, the toner image is fixed on the recording medium by heating, pressing, or the like. In the cleaning step, the toner remaining on the surface of the photosensitive drum after the toner image is transferred is removed by a cleaning blade and cleaned. The transfer of the toner image to the recording medium may be performed via an intermediate transfer medium.

The electrophotographic toner used for such image formation is produced by a polymerization method represented by, for example, a kneading and pulverizing method, a suspension polymerization method, and an emulsion polymerization aggregation method.
Among these, in the kneading and pulverization method, the toner raw material, which is mainly composed of a binder resin and a colorant and is added with a release agent and a charge control agent as necessary, is melt-kneaded, cooled and solidified. The toner is produced by pulverization and classification.

  In recent years, many efforts have been made in various technical fields from the viewpoint of global environmental conservation. At present, many product materials are produced from petroleum, but energy is required and carbon dioxide is generated when these materials are produced or incinerated. Such efforts to reduce energy and carbon dioxide are very important as a countermeasure against global warming.

  As a new approach to reducing carbon dioxide as a measure against global warming, the use of plant-derived resources called biomass has attracted much attention. Since carbon dioxide generated when burning biomass is originally atmospheric carbon dioxide taken by plants by photosynthesis, it is thought that the balance of atmospheric carbon dioxide is zero.

Thus, the property that does not affect the increase or decrease of carbon dioxide in the atmosphere is called carbon neutral, and the use of biomass that is carbon neutral is considered not to increase the amount of carbon dioxide in the atmosphere.
Biomass materials produced from such biomass are called biomass polymers, biomass plastics, non-petroleum polymer materials, etc., and such biomass materials are made from monomers called biomass monomers. .

In the field of electrophotography, efforts are being made to use biomass, which is an excellent resource for environmental safety and is an effective resource for suppressing an increase in carbon dioxide.
For example, Patent Document 1 contains a polyester resin having a softening point of 80 to 120 ° C. obtained by using rosin as an essential component, and a polyester resin having a softening point of 160 ° C. or more obtained by using a polyvalent epoxy compound as an essential component. A resin composition for an electrophotographic toner capable of obtaining a toner having both fixing property, hot offset resistance and development durability is disclosed.

JP 2008-122509 A

However, the melt-kneading method toner using carbon black as a colorant according to the method described in Patent Document 1 has a problem that fog occurs when the content of rosin in the binder resin is increased.
Accordingly, the present invention provides a toner containing a biomass-derived rosin and having a constant charge amount of toner even when carbon black is contained as a colorant and having reduced fog and toner scattering, and a method for producing the same. The task is to do.

  The inventors of the present invention have intensively studied, and as a result, the toner contains a binder resin containing 60 to 75% by weight of disproportionated rosin, carbon black, and a reaction product of disproportionated rosin and polyhydric alcohol. As a result, it has been found that the occurrence of fog and toner scattering can be suppressed, and the present invention has been completed.

Thus, according to the present invention, a binder resin containing 60-75% by weight of disproportionated rosin as a monomer component; carbon black; and a reaction product of disproportionated rosin and a polyhydric alcohol;
A toner characterized in that it is included is provided.

  Further, according to the present invention, the binder resin is obtained by polycondensing a polyester resin A obtained by polycondensation of an aromatic dicarboxylic acid, a disproportionated rosin and a polyhydric alcohol with an aromatic dicarboxylic acid and a polyhydric alcohol. A toner that is a mixture with the polyester resin B thus obtained is provided.

Further, according to the present invention, the binder resin comprises 20 to 60 parts by weight of the polyester resin A with respect to 100 parts by weight of the toner and a polyester having a viscosity of 10 ³ to 10 ⁵ Pa · S at the softening temperature of the polyester resin. A toner comprising resin B is provided.

  In addition, according to the present invention, there is provided a toner that contains the reaction product in a proportion of 0.1 to 5.0 parts by weight with respect to the binder resin, and is a carbon black dispersant.

  In addition, according to the present invention, there is provided a toner in which the reaction product has a molecular weight of 1000 to 8000 and is contained in a proportion of 0.4 to 15% by weight with respect to the carbon black.

Furthermore, according to the present invention, in a toner containing at least a binder resin, carbon black, and a release agent, the binder resin is a polyester resin A produced from an aromatic dicarboxylic acid, a disproportionated rosin, and a polyhydric alcohol; A mixing step of preparing a mixture by mixing a binder resin obtained by mixing with a polyester resin B produced from an aromatic dicarboxylic acid and a polyhydric alcohol, carbon black, and a release agent;
A melt-kneading step in which a reaction product of disproportionated rosin and polyhydric alcohol is mixed in the mixture, and melt-kneaded to produce a mixture;
A cooling and pulverizing step in which the kneaded product is cooled and solidified and pulverized to produce a pulverized product;
There is provided a method for producing a toner, comprising: a classification step of classifying the pulverized product; and an external addition step.

According to the present invention, a reaction product of a disproportionated rosin and a polyhydric alcohol is added to a melt-kneaded toner containing 60 to 75% by weight of a disproportionated rosin as a monomer component and carbon black. Therefore, occurrence of fog and toner scattering can be suppressed.
The mechanism for obtaining this effect is estimated as follows. That is, since the compatibility between the rosin component and the carbon black in the resin is low, it is considered that the carbon black is less likely to be uniformly mixed into the resin when the content of the rosin component is increased.
Therefore, just kneading the toner material using an open roll or a biaxial kneader, without performing a master batch process that imparts a high shearing force to the mixture of the binder resin and carbon black. It was difficult to uniformly disperse carbon black in the resin.

  On the other hand, when a reaction product of disproportionated rosin and polyhydric alcohol is added to a melt-kneaded toner containing carbon black and a binder resin containing 60 to 75% by weight of disproportionated rosin as a monomer component, carbon It is considered that the affinity between black and the rosin component in the resin is increased, and the carbon black is easily dispersed uniformly in the binder resin. As a result, it is presumed that the charge amount of the toner was stabilized and fogging could be prevented.

FIG. 6 is a process diagram illustrating an example of a procedure of a toner manufacturing method according to the present invention.

The toner according to the present invention contains, as a binder resin, Poeriester A obtained by polycondensation of aromatic dicarboxylic acid, rosin and polyhydric alcohol, and Polyester B obtained by polycondensation of polybasic acid and polyhydric alcohol.
The rosin used in the production of the above polyester A is a tall rosin obtained by steam distillation of raw tall oil produced as a by-product in the production process of pulping pine wood by the kraft method; There is a gum rosin obtained by steam-distilling the raw pine sprout; and a wood rosin obtained by distilling the harvested pine root stock into a chip and extracting it with an organic solvent, followed by further distillation. These rosins are obtained by a conventionally known production method.
About 90% of the rosin is a resin acid, and is mainly composed of a mixture of resin acids such as abietic acid, parastrinic acid, neoabietic acid, pimaric acid, dehydroabietic acid, isopimaric acid and sandaracopimalic acid.

The disproportionation reaction of rosin is usually performed by using a palladium activated carbon catalyst (US Pat. No. 2,177,530), a sulfur catalyst (Japanese Patent Publication No. 49-5360) or an iodine catalyst (Japanese Patent Laid-Open No. 51-34896). Done with.
By the above disproportionation reaction, two molecules of rosin react, one molecule increases to 3 double bonds and becomes an aromatic compound, and the other molecule hydrogenates one double bond of a conjugated double bond. Thus, these disproportionated rosins are characterized by being less susceptible to alteration than rosins having unstable conjugated double bonds.
Therefore, the rosin used for the polyester resin A in the present invention is preferably a disproportionated rosin from the viewpoint of stability.

The main component of disproportionated rosin is a mixture of dehydroabietic acid and dihydroabietic acid. Since the disproportionated rosin contains a bulky and rigid skeleton of the hydrophenanthrene ring, by introducing the disproportionated rosin as a component of the polyester, it appears more apparent than when using a rosin other than the disproportionated rosin. An increase in glass transition temperature can be promoted, and a toner having good storage stability can be obtained.
Therefore, the term “rosin” used in the present invention includes disproportionated rosin obtained by disproportionation of these rosins in addition to the above-mentioned tall rosin, gum rosin and wood rosin.

1. Toner Manufacturing Method FIG. 1 is a process diagram showing an example of the procedure of a toner manufacturing method of the present invention. The toner of the present invention contains a binder resin and a colorant as main components and is manufactured by the toner manufacturing method according to the present invention. The toner manufacturing method according to the present invention is a dry particle forming method, and includes a mixing step S1, a melt-kneading step S2, a cooling and pulverizing step S3, a classification step S4, and an external addition step S5.

(1) Mixing step S1
In the mixing step S1, the binder resin and the colorant are dry-mixed by a mixer to produce a mixture. At this time, additives are added as necessary. Examples of the additive include magnetic powder, release agent, charge control agent and the like.

Binder resin (binder resin)
The toner of the present invention contains polyester resin A and polyester resin B as binder resins.
A polyester resin is suitable as a raw material for a color toner because it is excellent in transparency and can impart good powder fluidity, low-temperature fixability and secondary color reproducibility to toner particles.
Polyester resin A and polyester resin B are obtained by polycondensing an acid component such as a polybasic acid and a polyhydric alcohol as a starting material.

Polyester resin A and polyester resin B are produced by a known polycondensation reaction method.
As the reaction method, transesterification or direct esterification can be applied. Also, polycondensation can be promoted by increasing the reaction temperature by pressurization, or by flowing an inert gas under reduced pressure or normal pressure. In the above reaction, the reaction may be promoted using a known and commonly used reaction catalyst such as at least one metal compound among antimony, titanium, tin, zinc, aluminum, and manganese. The addition amount of these reaction catalysts is preferably 0.01 to 1.0 part by weight based on 100 parts by weight of the total amount of the acid component and the polyhydric alcohol.

  In the production of the polyester resin A, aromatic dicarboxylic acid and rosin are used as the acid component of the starting material, and trivalent or higher alcohol is used as the polyhydric alcohol of the starting material. A polyol structure having an appropriate branch is formed by the reaction of the aromatic dicarboxylic acid and the trivalent or higher alcohol. By including an appropriate branched structure in the polyester resin, the low temperature fixability of the toner can be maintained without extremely increasing the softening temperature of the resin, and the molecular weight distribution of the resin can be broadened. Since a wide resin can be obtained, the offset resistance of the toner is improved.

  Examples of the aromatic dicarboxylic acid used in the polyester resin A include phthalic acid, terephthalic acid, isophthalic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid and the like. Further, as the acid component of the polyester resin A, an aromatic dicarboxylic acid derivative such as an aromatic dicarboxylic acid anhydride or a lower alkyl ester may be used instead of the aromatic dicarboxylic acid. Of the above aromatic dicarboxylic acid compounds, it is preferable to use at least one of terephthalic acid, isophthalic acid, and lower alkyl esters thereof.

  Terephthalic acid and isophthalic acid have a high electron resonance stabilization effect due to the aromatic ring skeleton, and are excellent in charging stability and can provide a resin having an appropriate strength. Examples of lower alkyl esters of terephthalic acid and isophthalic acid include dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, and dibutyl isophthalate. Of these, dimethyl terephthalate or dimethyl isophthalate is preferably used from the viewpoint of cost and handling.

  These aromatic dicarboxylic acid compounds can be used individually by 1 type, or can use 2 or more types together.

  Examples of the polyhydric alcohol used in the polyester resin A include trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol. At least one of these polyhydric alcohols can be used. Among these, glycerin is more preferable because a technique for producing from plant-derived raw materials has been established industrially, is easily available, and an effect of promoting utilization of biomass is obtained.

In the polyester resin A, the molar ratio of the polyhydric alcohol to the aromatic dicarboxylic acid compound is preferably 1.05 to 1.65.
When the molar ratio of the polyhydric alcohol to the aromatic dicarboxylic acid compound is less than 1.05, the molecular weight distribution on the high molecular weight side of the resin is broadened, and the Tm is increased to lower the low-temperature fixability of the toner. As a result of the inability to control the spread of the distribution, toner gelation occurs.
When the molar ratio of the polyhydric alcohol exceeds 1.65, since the polyester resin contains few branched structures, the softening temperature and the glass transition temperature are lowered, and as a result, the storage stability of the toner is lowered.

  As described above, the polyester resin A is obtained by polycondensation of aromatic dicarboxylic acid, rosin, and polyhydric alcohol as starting materials. In the present invention, in order to obtain a toner excellent in environmental safety, the content of the rosin in the total amount of the starting material is set to 60% by weight or more as a precondition of the polyester resin A.

The content of rosin is preferably 60 to 75 parts by weight with respect to 100 parts by weight of polyester resin A.
When the content of rosin is less than 60 parts by weight, the effect of protecting the global environment by using biomass is low, and when the content of rosin exceeds 75 parts by weight, the mechanical strength of the toner decreases and the powder flow Sexual deterioration occurs.

  Polyester resin A can further use an aliphatic polycarboxylic acid or an aromatic polycarboxylic acid having a carboxy group of three or more basic acids as the acid component, in addition to the above-mentioned aromatic dicarboxylic acid compound and rosin.

  Examples of the aliphatic polycarboxylic acid include alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid, succinic acid substituted with an alkyl group having 16 to 18 carbon atoms, fumaric acid, maleic acid, citraconic acid, and itaconic acid. Examples thereof include unsaturated dicarboxylic acids such as acid and glutaconic acid, and dimer acid.

  The content of the aliphatic polycarboxylic acid in the polyester resin A is preferably 0.5 to 15 mol, and more preferably 1 to 13 mol, per 100 mol of the aromatic dicarboxylic acid compound. When the content of the aliphatic polycarboxylic acid in the polyester resin A is in the above range, the low-temperature fixability of the toner is improved.

  Examples of the aromatic polycarboxylic acid having a carboxy group having three or more basic acids include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, and anhydrides thereof. These aromatic polycarboxylic acids can be used individually by 1 type, or may use 2 or more types together. Of these aromatic polycarboxylic acids, trimellitic anhydride is preferably used from the viewpoint of reactivity.

  The content of the aromatic polycarboxylic acid having a carboxy group having three or more basic acids in the polyester resin A is preferably 0.1 to 5 mol with respect to 100 mol of the aromatic dicarboxylic acid compound, and is preferably 0.5 to 0.5 mol. More preferably, it is 3 moles. If the content of the trivalent or higher valent aromatic polycarboxylic acid in the polyester resin A is less than 0.1 mol, the branched structure of the polyester resin A is not sufficient, and a polyester resin A having a broad distribution on the high molecular weight side is obtained. Therefore, the offset resistance of the toner may be reduced. On the other hand, when it exceeds 5 mol, the softening temperature of the polyester resin A becomes high, so that the low-temperature fixability of the toner may be lowered.

  Polyester resin A can further use at least one of an aliphatic diol and an etherified diphenol as a polyhydric alcohol, in addition to trihydric or higher alcohols.

  Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2,3- Butanediol, 1,4-butenediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 2-ethyl-2-methylpropane-1,3-diol, 2-butyl-2- Ethylpropane-1,3-diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-1,5-pentanediol, 2, 2,4-trimethyl-1,3-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-de Njioru, 3-hydroxy-2,2-dimethylpropyl over 3-hydroxy-2,2-dimethyl propanoate, diethylene glycol, triethylene glycol, dipropylene glycol, and the like. Of these aliphatic diols, ethylene glycol, 1,3-propanediol, or neopentyl glycol is preferably used from the viewpoint of reactivity with acids and the glass transition temperature of the resin. These aliphatic diols can be used alone or in combination of two or more.

  It is preferable that content of the aliphatic diol in the polyester resin A is 5-20 mol with respect to 100 mol of aromatic dicarboxylic acid compounds.

  Etherified diphenol is a diol obtained by addition reaction of bisphenol A and alkylene oxide. Examples of the alkylene oxide include ethylene oxide and propylene oxide. The alkylene oxide is preferably added so that the average number of added moles is 2 to 16 moles with respect to 1 mole of bisphenol A.

  The content of etherified diphenol in the polyester resin A is preferably 5 to 35 mol with respect to 100 mol of the aromatic dicarboxylic acid compound.

The content of the polyester resin A is preferably 20 to 60 parts by weight with respect to 100 parts by weight of the toner.
When the content of the polyester resin A is less than 20 parts by weight, the viscosity of the toner increases and the low-temperature fixability of the toner is impaired. On the other hand, when the content of the polyester resin A exceeds 60 parts by weight, the content of rosin is increased, so that the mechanical strength of the toner and the powder fluidity are decreased.

  The polyester resin B is a polyester resin substantially free of rosin and preferably has a high molecular weight and a high viscosity in order to impart high temperature offset resistance to the toner.

  As an acid component of the polyester resin B, the same aromatic dicarboxylic acid compound as that of the polyester resin A can be used. The aromatic dicarboxylic acid compound contained in the polyester resin A and the polyester resin B may be the same or different. In addition to the above aromatic dicarboxylic acid compound, the polyester resin B contains an aliphatic polycarboxylic acid similar to the polyester resin A or an aromatic polycarboxylic acid having a carboxy group of three or more basic acids as an acid component of the starting material. Further, it can be used. These acid components may be the same or different in polyester resins A and B.

  Further, as the acid component of the polyester resin B, polybasic acids such as saturated polybasic acids and unsaturated polybasic acids, acid anhydrides thereof, and lower alkyl esters thereof can be used.

  Saturated polybasic acids, saturated polybasic acids, and lower alkyl esters of saturated polybasic acids include, for example, adipic acid, sebacic acid, orthophthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, succinic anhydride, carbon Dibasic acids such as alkyl succinic acid, alkyl succinic anhydride, alkenyl succinic acid, alkenyl succinic anhydride; trimellitic acid, trimellitic anhydride, cyanuric acid, pyromellitic acid, pyromellitic anhydride, etc. Is mentioned.

  Examples of the unsaturated polybasic acid include maleic acid, maleic anhydride, fumaric acid and the like.

  A saturated polybasic acid and an unsaturated polybasic acid can be used individually by 1 type, or may use 2 or more types together. Moreover, you may use monobasic acids, such as benzoic acid and p-tert- butyl benzoic acid, as needed.

  As the polyhydric alcohol of the polyester resin B, trivalent or higher alcohols, aliphatic diols and etherified diphenols can be used in the same manner as the polyester resin A, and the same one as the polyester resin A may be used. Different ones may be used. In addition, alicyclic diols such as cyclohexanedimethanol may be used. A polyhydric alcohol may be used independently and may use 2 or more types together. Furthermore, you may use monoalcohols, such as a stearyl alcohol, in the range which does not impair the effect of this invention as needed.

The viscosity of the polyester resin B is preferably 10 ³ to 10 ⁵ Pa · s at the softening temperature of the polyester resin A.
When the viscosity of the polyester resin B at the softening temperature of the polyester resin A is less than 10 ³ Pa · s, the hot offset resistance of the toner cannot be obtained.
In addition, when the viscosity B of the polyester resin B at the softening temperature of the polyester resin A exceeds 10 ⁵ Pa · s, the difference in melt viscosity between the polyester resin A and the polyester resin B during kneading is large, and the resin mixing property becomes poor. Further, the dispersibility of the polyester resin A and the polyester resin B in the toner becomes non-uniform. As a result, in the toner particles, the portion where the ratio of the polyester resin A is high is easily destroyed, and fine particles having a small particle diameter are generated by the destruction. Such fine powder widens the particle size distribution and charge distribution, and causes problems such as image fogging.

  The glass transition temperatures of the polyester resin A and the polyester resin B are not particularly limited and can be appropriately selected from a wide range. However, considering the storage stability and low-temperature fixability of the obtained toner, 45 to 80 ° C. is preferable, and 50 to 65 is preferable. More preferably, it is ° C. When the glass transition temperatures of the polyester resin A and the polyester resin B are less than 45 ° C., the storage stability of the toner becomes insufficient, so that the toner is likely to thermally aggregate inside the image forming apparatus, resulting in development failure. In addition, the temperature at which hot offset begins to occur (hereinafter referred to as “hot offset start temperature”) decreases.

  “Hot offset” means that when a toner is heated and pressed by a fixing member and fixed on a recording medium, the cohesive force of the heated toner particles is less than the adhesive force between the toner and the fixing member, so that the toner layer This is a phenomenon in which the toner is divided and a part of the toner adheres to the fixing member and is removed. On the other hand, when the glass transition temperatures of the polyester resins A and B exceed 80 ° C., the low-temperature fixability of the toner is lowered and fixing failure occurs.

  As long as the object of the present invention can be achieved, the binder resin includes a polystyrene polymer, a polystyrene copolymer such as a styrene-acrylic resin, a polyester resin other than the polyester resin, and the like. A resin used as a landing resin may be used together with the polyester resin.

Colorant As the colorant contained in the toner of the present invention, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field may be used. Of the dyes and pigments, it is preferable to use a pigment. Since the pigment is superior in light resistance and color developability compared to the dye, a toner excellent in light resistance and color developability can be obtained.

  In order to uniformly disperse the colorant in the polyester resin, the disproportionated rosin and the polyhydric alcohol are used in a melt-kneading toner containing a binder resin containing 60 to 75% by weight of disproportionated rosin as a monomer component and carbon black. And the reaction product was added. It is considered that the affinity between the carbon black and the rosin component in the resin is increased, and the carbon black is easily dispersed uniformly in the binder resin.

  As the kneading machine, a known kneading machine can be used. For example, a general kneading machine such as a kneader, a twin-screw extruder, a two-roll mill, a three-roll mill, or a lab blast mill can be used. More specifically, for example, TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (all of which are trade names, manufactured by Ikegai Co., Ltd.), etc. Extruder, Needex (trade name, manufactured by Mitsui Mining Co., Ltd.) and other open roll type kneaders. The melt kneading may be performed using a plurality of kneaders.

In the case of a black colorant such as carbon black, the concentration of the colorant in the toner is preferably 5 to 12% by weight, and more preferably 6 to 8% by weight.
The colorant concentration other than black is preferably 3 to 8% by weight, and more preferably 4 to 6% by weight. When using a masterbatch, it is preferable to adjust the amount of the masterbatch so that the colorant concentration in the toner falls within the above range. When the colorant concentration is within the above range, it is possible to obtain a toner that suppresses the filler effect due to the addition of the colorant and has high coloring power, and has a sufficient image density and high color developability. A good image with excellent image quality can be formed.

Magnetic powder Examples of the magnetic powder contained in the toner of the present invention include magnetite, γ-hematite, and various ferrites.

Release Agent As the release agent contained in the toner of the present invention, those commonly used in this field can be used, and examples thereof include wax. As waxes, petroleum waxes such as paraffin wax, carnauba wax (carnauba wax), natural wax such as rice wax, synthetic wax such as polypropylene wax, polyethylene wax, and Fischer-Tropsch wax, and coal-based wax such as montan wax Examples thereof include waxes, alcohol waxes, and ester waxes.

  The release agent contained in the toner of the present invention may be used alone or in combination of two or more. The addition amount of the release agent is not particularly limited, and is appropriately selected from a wide range according to various conditions such as the type and content of other components such as a binder resin and a colorant and the characteristics required for the toner to be produced. Although it can be selected, it is preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin. When the addition amount of the release agent is less than 3 parts by weight, the low-temperature fixability and the hot offset resistance are not sufficiently improved. When the addition amount of the release agent exceeds 10 parts by weight, the dispersibility of the release agent in the kneaded product is lowered, and a toner having a certain performance cannot be obtained stably. In addition, a phenomenon called filming occurs in which the toner is fused in the form of a film (film) on the surface of an image carrier such as a photoreceptor.

The melting point (Tm) of the release agent is preferably 50 to 180 ° C.
When the melting point is less than 50 ° C., the release agent melts in the developing device, the toner particles aggregate, and filming on the surface of the photoreceptor occurs.
On the other hand, if the melting point exceeds 180 ° C., the release agent cannot be sufficiently eluted when the toner is fixed on the recording medium, and the hot offset resistance is not sufficiently improved.

Charge Control Agent As the charge control agent contained in the toner of the present invention, a charge control agent for positive charge control and negative charge control commonly used in this field can be used.

  Examples of charge control agents for positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, triphenylmethane Derivatives, guanidine salts, amidine salts and the like can be mentioned.

  The charge control agents for controlling negative charges include chromium azo complex dyes, iron azo complex dyes, cobalt azo complex dyes, chromium complexes of salicylic acid and salicylic acid derivatives, zinc complexes, aluminum complexes and boron complexes, salicylate compounds, naphtholic acid and naphtholic acid. Surfactants such as chromium complexes, zinc complexes, aluminum complexes and boron complexes of derivatives, naphtholate compounds, benzylate compounds, long chain alkylcarboxylates, and long chain alkylsulfonates can be mentioned.

  The addition amount of the charge control agent is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the binder resin.

  A known mixer can be used in the mixing step S1, for example, a Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), a super mixer (trade name, manufactured by Kawata Co., Ltd.), a mechano mill (trade name, Henschel type mixing devices such as Okada Seiko Co., Ltd., Ongmill (trade name, manufactured by Hosokawa Micron Co., Ltd.), Hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo System (trade name, Kawasaki Heavy Industries Ltd.) Company-made).

(2) Melt-kneading step S2
In the melt-kneading step S2, the mixture produced in the mixing step is melt-kneaded by a kneader to produce a melt-kneaded product in which an additive having a colorant added as necessary is dispersed in a binder resin. .

  As a kneader used in the melt-kneading step, a known one can be used, and the same one as the above-mentioned kneader used for preparing a masterbatch can be used. Melt kneading may be performed using a plurality of kneaders.

  The temperature of the melt kneading depends on the kneader used, but is preferably 80 to 200 ° C. By performing melt-kneading at a temperature in such a range, an additive to which a colorant is added as necessary can be uniformly dispersed in the binder resin.

(3) Cooling and grinding step S3
In the cooling and pulverizing step S3, the melt-kneaded product obtained in the melt-kneading step is cooled and solidified and pulverized to obtain a pulverized product.

  The cooled and solidified melt-kneaded product is coarsely pulverized into a coarsely pulverized product having a volume average particle size of about 100 μm to 5 mm by a hammer mill or a cutting mill, and the obtained coarsely pulverized product has, for example, a volume average particle size of 15 μm or less. Until further pulverization. For finely pulverizing the coarsely pulverized product, for example, a jet pulverizer using a supersonic jet stream, or a coarsely pulverized product in a space formed between a rotor (rotor) rotating at high speed and a stator (liner) An impact type pulverizer that introduces and pulverizes can be used.

(4) Classification process S4
In the classification step S4, the pulverized product obtained in the cooling and pulverization step S3 is classified by a classifier to remove excessively pulverized toner particles and coarse toner particles, thereby obtaining an unexternally added toner. The excessively pulverized toner particles and coarse toner particles can be collected and reused for the production of other toners.

  For the classification, a known classifier capable of removing excessively pulverized toner particles by classification using centrifugal force and wind force can be used. For example, a swirl type wind classifier (rotary wind classifier) or the like can be used.

The volume average particle diameter of the non-externally added toner obtained after classification is preferably 3 to 15 μm. In order to obtain a high-quality image, the volume average particle diameter of the non-externally added toner is preferably 3 to 9 μm, and more preferably 5 to 8 μm.
When the volume average particle size of the non-externally added toner is less than 3 μm, the toner has a small particle size, so that high charging and low fluidization occur. Due to the high charging and low fluidization of the toner, the toner is not stably supplied to the photoreceptor, and background fogging and a decrease in image density occur. When the volume average particle size of the non-externally added toner exceeds 15 μm, the particle size of the toner is large and a high-definition image cannot be obtained. In addition, as the particle size increases, the specific surface area of the toner decreases and the charge amount of the toner decreases. As a result, the toner is not stably supplied to the photoreceptor, and internal contamination due to toner scattering occurs.

(5) External addition process S5
In the external addition step S5, the toner is obtained by mixing the non-external addition toner obtained in the classification step S4 and the external additive. By adding the external additive, the fluidity of the toner and the cleaning property of the residual toner on the surface of the photoreceptor are improved, and filming on the photoreceptor can be prevented. Non-externally added toner to which no external additive is added can also be used as the toner.

  External additives include inorganic oxides such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, compounds such as acrylates, methacrylates, and styrene, or copolymer resins of these compounds Examples thereof include fine particles, fluororesin fine particles, silicone resin fine particles, and higher fatty acids such as stearic acid, or metal salts of these higher fatty acids, carbon black, graphite fluoride, silicon carbide, boron nitride, and the like.

  The external additive is preferably surface-treated with a silicone resin, a silane coupling agent or the like. Moreover, it is preferable that the addition amount of an external additive is 0.5-5 weight part with respect to 100 weight part of binder resin.

The number average particle diameter of primary particles of the external additive is preferably 10 to 500 nm.
When the number average particle diameter of the primary particles of the external additive is within such a range, the fluidity of the toner is further improved.

The BET specific surface area of the external additive is preferably 20 to ²⁰⁰ m ² / g.
When the BET specific surface area of the external additive is in such a range, appropriate fluidity and chargeability can be imparted to the toner.

2. Toner The toner of the present invention is manufactured by the toner manufacturing method according to the above embodiment. The toner obtained by the above toner production method has sufficient mechanical strength and is excellent in hot offset resistance and charging stability.

3. Developer The toner according to the present invention can be used as a one-component developer composed only of toner, or can be mixed with a carrier and used as a two-component developer.

  As the carrier, a known carrier can be used. For example, a resin-coated carrier or a resin in which iron or copper, zinc, nickel, cobalt, manganese, chromium or the like alone or a composite ferrite and carrier core particles are coated with a coating material. And a resin-dispersed carrier in which magnetic particles are dispersed.

  Known coating materials can be used, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin , Polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, and the like.

  The resin used for the resin-dispersed carrier is not particularly limited, and examples thereof include styrene acrylic resin, polyester resin, fluorine resin, and phenol resin. Either of them is preferably selected according to the toner component, and one kind can be used alone, or two or more kinds can be used in combination.

The shape of the carrier is preferably a spherical shape or a flat shape. The particle diameter of the carrier is not particularly limited, but is preferably 10 to 100 μm, and more preferably 20 to 50 μm, in consideration of high image quality.
When the carrier particle size is 100 μm or less, the chance of contact between the toner and the carrier is increased, each toner particle can be appropriately charged, non-image area fog is not generated, and a high-quality image is formed. Can do.

Furthermore, the volume resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, more preferably 10 ¹² Ω · cm or more.
The volume resistivity of the carrier is determined by putting carrier particles in a container having a cross-sectional area of 0.50 cm ² and tapping, then applying a load of 1 kg / cm ² to the particles packed in the container and placing the load between the load and the bottom electrode. It is a value obtained from a current value when a voltage generating an electric field of 1000 V / cm is applied. When the resistivity is low, the carrier is charged when a bias voltage is applied to the developing sleeve, and the carrier particles easily adhere to the photoreceptor. Further, breakdown of the bias voltage is likely to occur.

The magnetization strength (maximum magnetization) of the carrier is preferably 10 to 60 emu / g, more preferably 15 to 40 emu / g.
Under a general developing roller magnetic flux density condition, if it is less than 10 emu / g, the magnetic binding force does not work, which causes carrier scattering.
On the other hand, if the magnetization strength exceeds 60 emu / g, the carrier spikes become too high in the non-contact development, and it becomes difficult to maintain the non-contact state between the image carrier and the toner. Further, in the contact development, a sweep is likely to appear in the toner image.

  The use ratio of the toner and the carrier in the two-component developer is not particularly limited, and can be appropriately selected according to the kind of the toner and the carrier. Further, the coverage of the carrier with the toner is preferably 40 to 80%.

Example 1
[Preparation of polyester resin A]
In a reaction vessel equipped with a stirrer, a heating device, a thermometer, a condenser, a fractionator, and a nitrogen introduction tube, 305 g of terephthalic acid, 55 g of isophthalic acid, 30 g of trimellitic anhydride and disproportionated rosin as acid components (Product name Longis R, manufactured by Arakawa Chemical Industries, Ltd .: acid value 157.2 mg KOH / g) 1400 g, 300 g of glycerin and 150 g of 1,3-propanediol as alcohol components, 1.79 g of tetra-n-butyl titanate as a reaction catalyst (Equivalent to 0.080 parts by weight with respect to 100 parts by weight of the total amount of the acid component and the alcohol component) The raw materials were stirred under a nitrogen atmosphere, and the water produced was distilled off at 250 ° C. while distilling off the generated water. After the polycondensation reaction for a period of time, confirming that the predetermined softening temperature has been reached with a flow tester, the reaction is terminated, and the polyester resin 2000 g of A (glass transition temperature 60 ° C., softening temperature 112 ° C., weight average molecular weight 2800, Mw / Mn = 2.3, acid value 24 mgKOH / g) was obtained.

[Preparation of polyester resin B]
In a reaction vessel equipped with a stirrer, a heating device, a thermometer, a cooling tube, a fractionation device, and a nitrogen introduction tube, 350 g of terephthalic acid, 400 g of isophthalic acid, and 50 g of trimellitic anhydride as an alcohol component as an alcohol component , 125 g of glycerin, PO2 molar adduct of bisphenol A (trade name Newpol BP-2P, Sanyo Chemical Industries) 350 g, and PO3 molar adduct of bisphenol A (trade name Newpol BP-3P, Sanyo Chemical Industries) 450 g, and 1.38 g of tetra-n-butyl titanate were added as a reaction catalyst These materials were agitated in a nitrogen atmosphere and subjected to a polycondensation reaction at 220 ° C. for 10 hours while distilling off the generated water. Next, the reaction was carried out under a reduced pressure of 5 to 20 mmHg, and a predetermined softening temperature was reached by a flow tester. Then, the reaction was completed to obtain 1500 g of polyester resin B (glass transition temperature 61 ° C., softening temperature 147 ° C., weight average molecular weight 29500, Mw / Mn = 10.8, acid value 22 mmHg, THF insoluble content 40%). It was.

[Preparation of reaction product C]
In a reaction vessel equipped with a stirrer, a heating device, a thermometer, a condenser, a fractionator, and a nitrogen introduction tube, 305 g of terephthalic acid, 55 g of isophthalic acid, 30 g of trimellitic anhydride and disproportionated rosin as acid components (Product name Longis R, manufactured by Arakawa Chemical Industries, Ltd .: acid value 157.2 mg KOH / g) 1400 g, 400 g of glycerol and 200 g of 1,3-propanediol as alcohol components, 1.79 g of tetra-n-butyl titanate as a reaction catalyst (Corresponding to 0.080 parts by weight with respect to 100 parts by weight of the total amount of the acid component and the alcohol component) These raw materials were stirred under a nitrogen atmosphere and distilled off at 250 ° C. while distilling off the generated water. After the polycondensation reaction for a time, it was confirmed that the predetermined softening temperature was reached by a flow tester, the reaction was terminated, and polyester resin C 2050 g (glass transition temperature 55 ° C., softening temperature 111 ° C., weight average molecular weight 2520, Mw / Mn = 1.9, acid value 11 mgKOH / g) was obtained.

<Mixing step S1>
Polyester resin A1, polyester resin B, carbon black (trade name: MA-77, manufactured by Mitsubishi Chemical Corporation), reaction product C, and charge control agent (trade name: LR-147, manufactured by Nippon Carlit Co., Ltd.) And a silane coupling agent (trade name: Z-6040, manufactured by Toray Dow Corning Co., Ltd.) and a release agent (polyethylene wax, trade name: Licowax PE-130 Powder, manufactured by Clariant, melting point: 127 ° C.) :
Polyester resin A: 35.4 parts Polyester resin B; 53.2 parts Carbon black: 7.1 parts Reaction product C: 2.0 parts Charge control agent: 1.4 parts Release agent: 0.9 parts Were mixed for 10 minutes using a Henschel mixer (trade name: FM20C, manufactured by Mitsui Mining Co., Ltd.) to prepare 4900 g of a mixture.

<Melt-kneading step S2>
4900 g of the mixture obtained in the mixing step S1 was mixed with a kneader (trade name: biaxial kneader PCM-60, manufactured by Ikegai Co., Ltd.) at a cylinder set temperature of 80 ° C. to 120 ° C. (maximum temperature 120 ° C.), and the number of revolutions. The mixture was melt-kneaded at 250 rpm and a supply rate of 5 kg / h to obtain 4000 g of a melt-kneaded product.

<Cooling and grinding step S3>
After 4000 g of the melt-kneaded product obtained in the melt-kneading step S2 was cooled to room temperature and solidified, it was coarsely pulverized with a cutter mill (trade name: VM-16, manufactured by Orient Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized by a counter jet mill (trade name: AFG, manufactured by Hosokawa Micron Corporation).

<Classification step S4>
3500 g of the pulverized product obtained in the cooling and pulverizing step S3 was classified with a rotary classifier (trade name: TSP separator, manufactured by Hosokawa Micron Corporation) to obtain 3000 g of non-externally added toner.

<External addition process S5>
Hydrophobic silica fine powder A (trade name R974, manufactured by Nippon Aerosil Co., Ltd.) surface-treated with a silane coupling agent and dimethyl silicone oil with respect to 100 parts by weight (500 g) of the non-externally added toner obtained in the classification step S4. ) (BET specific surface area 170m ² / g) and titanium oxide (trade name T805, manufactured by Nippon Aerosil Co.) (BET specific surface area 50m ² /g)0.5 parts (2.5 g) was added, Henschel mixer (trade Name: FM mixer, manufactured by Mitsui Mining Co., Ltd., to obtain 2000 g of the toner of Example 1 (volume average particle size 6.7 μm, CV value 25%).

Example 2
The toner of Example 2 (volume average particle diameter of 6.7 μm, CV value of 25%) is the same as Example 1 except that the number of additions of the reaction product of polyhydric alcohol and polymer is changed to 0.05 parts. ) 2000 g was obtained.

Example 3
The toner of Example 3 (volume average particle diameter of 6.7 μm, CV value of 25%) was obtained in the same manner as in Example 1 except that the addition part of the reaction product of polyhydric alcohol and polymer was changed to 8.0 parts. ) 2000 g was obtained.

Comparative Example 1
Except that the disproportionated rosin was changed to 10% by weight as the monomer component, 2000 g of the toner of Comparative Example 1 (volume average particle diameter 6.7 μm, CV value 25%) was obtained in the same manner as in Example 1.

Comparative Example 2
The toner of Comparative Example 2 (volume average particle size 6.7 μm, CV value 25%) (2000 g) was obtained in the same manner as in Example 2 except that the disproportionated rosin was changed to 10% by weight as the monomer component. It was.

Comparative Example 3
Except that the disproportionated rosin was changed to 10% by weight as the monomer component, 2000 g of the toner of Comparative Example 3 (volume average particle size 6.7 μm, CV value 25%) was obtained in the same manner as Example 3.

[Fog density]
Using a whiteness meter (trade name: Z-Σ90 COLOR MEASURING SYSTEM, manufactured by Nippon Denshoku Industries Co., Ltd.), the whiteness of the non-image area (0% density) is measured and measured in advance. The difference from the degree was determined, and the difference was defined as the fog density, and the evaluation was performed according to the following criteria.

The evaluation standards for fog density are as follows.
“G”: good: The fog density is less than 0.5. There is almost no fogging with the naked eye.
“NB”: not bad (not bad): no problem in actual use. The fog density is 0.5 to less than 1.0. A little bit can be seen with the naked eye.
“B”: bad (bad): The fog density is 1.0 or more. The fog can be clearly confirmed with the naked eye.

Using the evaluation results of the charge amount ratio, image density, and fog density, charging stability was evaluated according to the following criteria.
“G”: good (good): evaluation results of charge amount ratio, image density, and fog density are “good”.
“NB”: not bad (not bad): Among the evaluation results of the charge amount ratio, the image density, and the fog density, at least one is Δ and there is no x.
“B”: bad (bad): At least one of the evaluation results of the charge amount ratio, the image density, and the fog density is “x”.

[Preservation]
Preservability was evaluated using the mesh-up rate. 100 g of toner was put in a polyethylene container and sealed, and left in a constant temperature bath at 50 ° C. for 48 hours. The left-to-stand toner was vibrated at 60 Hz for 1 minute using a vibration sieve equipped with a 200-mesh screen, and the weight of the toner remaining on the mesh screen was measured. The ratio of the toner remaining on the mesh screen is defined as a mesh-up rate, and the following formula (1):
Mesh up rate (%)
= {Weight of toner remaining on mesh screen (g) / 100 (g)} × 100 (1)
Based on the above, the mesh-up rate was calculated. The lower the mesh-up rate, the better the storage stability of the toner in a high temperature environment.

[Toner scattering]
Toner scattering was evaluated by aging in an actual machine.
The scattering was evaluated according to the following criteria.
"G": good (good): The fog is hardly confirmed with the naked eye.
“NB”: not bad (not bad): no problem in actual use. A little can be confirmed with the naked eye.
“B”: bad (defective): Visible to the naked eye.

“G”: good: all evaluation items are “G”.
“B”: bad (bad): There is at least one “B” in all evaluation items.
“NB”: No bad: Other than the above

  In Example 1, since the amount of glycerin added was moderate, results with good fog density and storage stability were obtained. However, in Example 3, the glycerin concentration with high hydration property was increased, so that the storage stability was considered to be deteriorated.

  From these results, when a reaction product of a disproportionated rosin and a polyhydric alcohol is added in a melt-kneaded toner containing 65 to 70 wt% of a disproportionated rosin as a monomer component and carbon black, It is considered that the affinity between the carbon black and the rosin component in the resin is increased, and the carbon black is easily dispersed uniformly in the binder resin. As a result, it is presumed that the charge amount of the toner was stabilized and fogging could be prevented.

  From these results, when a reaction product of a disproportionated rosin and a polyhydric alcohol is added in a melt-kneaded toner containing 65 to 70 wt% of a disproportionated rosin as a monomer component and carbon black, It is considered that the affinity between the carbon black and the rosin component in the resin is increased, and the carbon black is easily dispersed uniformly in the binder resin. As a result, it is presumed that the charge amount of the toner was stabilized and fogging could be prevented.

  According to the present invention, a reaction product of a disproportionated rosin and a polyhydric alcohol is added to a melt-kneaded toner containing 65 to 70% by weight of a disproportionated rosin as a monomer component and carbon black. Thus, a toner in which the occurrence of fogging and toner scattering is suppressed is provided.

Claims (9)

Binder resin containing 60 to 75% by weight of disproportionated rosin as a monomer component, carbon black, and reaction product of disproportionated rosin and polyhydric alcohol.
A toner comprising:   A polyester resin A obtained by polycondensing an aromatic dicarboxylic acid, a disproportionated rosin and a polyhydric alcohol, and a polyester resin B obtained by polycondensing an aromatic dicarboxylic acid and a polyhydric alcohol. The toner according to claim 1, which is a mixture. 2. The binder resin contains 20 to 60 parts by weight of polyester resin A and polyester resin B having a viscosity of 10 ³ to 10 ⁵ Pa · S at a softening temperature of the polyester resin with respect to 100 parts by weight of toner. Or the toner according to 2.   The toner according to claim 1, wherein the reaction product is contained at a ratio of 0.1 to 5.0 parts by weight with respect to the binder resin in the previous period.   The toner according to claim 1, wherein the reaction product is a carbon black dispersant.   The toner according to claim 1, wherein the reaction product has a molecular weight of 1000 to 8000.   The toner according to claim 1, wherein the reaction product is contained at a ratio of 0.4 to 15 wt% with respect to the carbon black.   The toner according to claim 1, wherein the polyhydric alcohol is glycerin. In a toner containing at least a binder resin, carbon black, and a release agent, the binder resin is a polyester resin A produced from an aromatic dicarboxylic acid, a disproportionated rosin and a polyhydric alcohol, and an aromatic dicarboxylic acid and a polyhydric alcohol. A mixing step of preparing a mixture by mixing a binder resin obtained by mixing with polyester resin B produced from the above, carbon black, and a release agent;
A melt-kneading step in which a reaction product of disproportionated rosin and polyhydric alcohol is mixed in the mixture, and melt-kneaded to produce a mixture;
A cooling and pulverizing step in which the kneaded product is cooled and solidified and pulverized to produce a pulverized product;
A method for producing a toner, comprising: a classification step of classifying the pulverized product; and an external addition step.

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