JP5419215B2 - toner - Google Patents

Description

  The present invention relates to a toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and an image forming method using the toner.

  To meet the recent demands for speeding up and downsizing, there is a demand for toner that can be fixed at a lower temperature. In order to meet this requirement, a toner using a crystalline resin and an amorphous resin as a binder resin has been proposed. A toner using such a crystalline resin and an amorphous resin improves the low-temperature fixability but tends to decrease the toner strength. As a result, with higher speed and smaller size, when more mechanical or thermal stress is applied, the charging stability is lowered, the photoreceptor is fogged, and the solid followability tends to be poor. It has become. Especially when used in a non-magnetic one-component developing device that charges toner by friction with the developing blade, or when used in an oil-less non-magnetic one-component developing device that requires the toner to contain a large amount of a release agent. The problem is a big issue.

  To solve these problems, it has been shown that non-magnetic one-component developing electrostatic charge developing toner containing benzoguanamine resin fine particles and inorganic particles and having a specific dielectric constant and dielectric loss tangent reduces fog (see Patent Document 1). ). Further, a polyester having an acid value of 5 mg KOH / g or more and a volume average particle size of 0.09 to 0.8 obtained by condensation polymerization of a carboxylic acid component and an alcohol component containing 5 mol% or more of an alkylene oxide adduct of bisphenol A. It has been shown that the toner used in the non-magnetic one-component development system containing melamine resin fine particles having a μm triazine skeleton has excellent charge start-up properties (see Patent Document 2).

  Further, a block copolymer comprising 3 to 50 parts by weight of crystalline polyester and 97 to 50 parts by weight of an ionically crosslinked amorphous vinyl polymer and having a chloroform insoluble content of 3 to 10% by weight. Alternatively, it is shown that a toner containing a graft copolymer as a binder resin is excellent in offset resistance and low-temperature fixability (see Patent Document 3).

JP 2000-3066 A JP 2003-57869 A JP-A-4-81770

  However, these toners have a problem in that fog suppression and improvement in solid follow-up are insufficient for higher speed and smaller machines.

  An object of the present invention is to provide a toner excellent in low-temperature fixability, suppressed in fog and white background stains, excellent in solid followability and halftone image density, and an image forming method using the toner.

The present invention
[1] A toner comprising toner base particles containing a binder resin and an external additive, wherein the binder resin comprises a crystalline resin and an amorphous resin, and the crystalline resin has a carbon number of 2 to Containing a composite resin comprising a polycondensation resin component obtained by condensation polymerization of an alcohol component containing 10 aliphatic diols and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and a styrene resin component The weight ratio of the condensation polymerization resin component to the styrene resin component (condensation polymerization resin component / styrene resin component) in the composite resin is 50/50 to 95/5, and the external additive is an average particle A toner comprising 0.1 to 0.8 μm in diameter of melamine resin fine particles, wherein the content of the melamine resin fine particles is 0.03 to 1.0 part by weight with respect to 100 parts by weight of the toner base particles, and [2] 1] Use of the toner described in a non-magnetic one-component developing device That, an image forming method.

  The toner of the present invention has excellent low-temperature fixability, suppresses fogging and white background stains, and exhibits excellent effects in solid followability and halftone image density. The toner of the present invention has an excellent effect even when used in a non-magnetic one-component developing device, particularly an oilless non-magnetic one-component developing device in which a toner needs to contain a large amount of a release agent.

  The toner of the present invention is a toner containing toner base particles including a binder resin including a crystalline resin and an amorphous resin and an external additive, wherein the crystalline resin is an aliphatic diol having 2 to 10 carbon atoms. A composite resin comprising a condensation polymerization resin component obtained by condensation polymerization of an alcohol component containing a carboxylic acid component containing an aromatic dicarboxylic acid compound, and a styrene resin component, and the external additive is It has a great feature in that it contains melamine resin fine particles with an average particle size of 0.1 to 0.8 μm. It has an excellent effect.

  Although the details of the reason why the effect of the present invention is achieved are not clear, the melamine resin fine particles having a specific average particle size used in the present invention are more suitable than other resin particles such as fluorine resin particles. Due to the hardness, even if mechanical or thermal stress is applied to the toner, detachment or deformation from the toner base particles hardly occurs, and excessive aggregation between the toner particles is suppressed. On the other hand, when the conventional binder resin is designed to have a low melt viscosity in order to achieve low-temperature fixability, the strength of the toner base particles is lowered and the effect of the resin fine particles is not exhibited. However, since the composite resin used in the present invention includes a styrene resin component having a high glass transition point and a crystalline polycondensation resin component, even if the melt viscosity is designed low to achieve low temperature fixability. The strength of the toner base particles including the composite resin is maintained, and the external additive including the melamine resin fine particles is prevented from being detached from the toner base particles or embedded in the toner base particles. Excessive aggregation is suppressed, and charging stability of the toner is maintained. As a result, it is considered that the low-temperature fixability of the toner is maintained, fogging and white background contamination are suppressed, and the solid followability and halftone image density are improved.

  In the present invention, the binder resin is composed of a crystalline resin and an amorphous resin from the viewpoint of improving the low-temperature fixability of the toner, and contains an aliphatic diol having 2 to 10 carbon atoms as the crystalline resin. It is preferable that a main component is a composite resin including a condensation polymerization resin component obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and a styrene resin component.

  Here, the crystallinity of the resin is represented by the crystallinity index defined by the ratio between the softening point and the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the value of [softening point / maximum endothermic peak temperature]. The crystalline resin has a crystallinity index of 0.6 to 1.4, preferably 0.7 to 1.2, more preferably 0.9 to 1.2, and the amorphous resin is a resin having a value of 1.4 or less than 0.6. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. The maximum peak temperature is the melting point if the difference from the softening point is within 20 ° C., and the peak due to the glass transition if the difference from the softening point exceeds 20 ° C.

  In the present invention, the polycondensation resin component constituting the composite resin improves the low-temperature fixability of the toner, suppresses fogging and white background stains, and improves the solid followability and halftone image density. A resin obtained by polycondensation of an alcohol component containing ˜10 aliphatic diols and a carboxylic acid component containing an aromatic dicarboxylic acid compound.

  Examples of the condensation polymerization resin component include polyester, polyester / polyamide, and the like. From the viewpoint of low-temperature fixability of the toner, polyester is preferable.

  In the present invention, the alcohol component of the condensation polymerization resin is an aliphatic diol having 2 to 10 carbon atoms, preferably 4 to 8 carbon atoms, more preferably 4 to 6 carbon atoms, from the viewpoint of enhancing the crystallinity of the composite resin. contains.

  Examples of the aliphatic diol having 2 to 10 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 1,4-butenediol, and the like, particularly from the viewpoint of enhancing the crystallinity of the composite resin, α, ω-linear alkanediol is preferred, 1,4-butanediol and 1,6-hexanediol are more preferred, and 1,6-hexanediol is more preferred.

  From the viewpoint of enhancing the crystallinity of the composite resin, the content of the aliphatic diol having 2 to 10 carbon atoms is preferably 70 mol% or more, more preferably 80 to 100 mol%, and still more preferably 90 to 100 mol in the alcohol component. Mol%. In particular, the proportion of one kind of the aliphatic diol having 2 to 10 carbon atoms in the alcohol component is preferably 50 mol% or more, more preferably 60 to 100 mol%.

  The alcohol component may contain a polyhydric alcohol component other than the aliphatic diol having 2 to 10 carbon atoms.

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, each being a positive number, and the sum of x and y. 1 to 16 is preferable, 1 to 8 is more preferable, and 1.5 to 4 is more preferable)
An aromatic diol such as an alkylene oxide adduct of bisphenol A represented by the formula: trivalent or higher alcohols such as glycerin, pentaerythritol, trimethylolpropane, sorbitol, and 1,4-sorbitan.

  In the present invention, the carboxylic acid component of the condensation polymerization resin contains an aromatic dicarboxylic acid compound from the viewpoint of suppressing fogging of the toner and improving solid followability and halftone image density.

  As the aromatic dicarboxylic acid compound, those having 8 to 12 carbon atoms are preferable. Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, anhydrides of these acids, and alkyls thereof (1 to 8 carbon atoms). ) Esters. In addition, although a dicarboxylic acid compound refers to dicarboxylic acid, its anhydride, and its alkyl (C1-C8) ester, in these, dicarboxylic acid is preferable. Moreover, a preferable carbon number means the carbon number of the dicarboxylic acid part of a dicarboxylic acid compound.

  The content of the aromatic dicarboxylic acid compound is preferably 70 to 100 mol%, more preferably 90 to 100 mol% in the carboxylic acid component, from the viewpoint of suppressing toner fogging and improving solid followability and halftone image density. Mol%.

  The carboxylic acid component may contain a polyvalent carboxylic acid compound other than the aromatic dicarboxylic acid compound. Examples of the polyvalent carboxylic acid compound include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, Aliphatic dicarboxylic acids such as itaconic acid, glutaconic acid, succinic acid, adipic acid, succinic acid substituted with an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms, and alicyclic rings such as cyclohexanedicarboxylic acid Dicarboxylic acid, trimellitic acid, trivalent or higher aromatic polyvalent carboxylic acid such as 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, etc., and their acid anhydrides and alkyl (C1-8) esters Etc.

  In addition, in this specification, the both reactive monomers mentioned later shall not be included in calculation of content of an alcohol component or a carboxylic acid component.

  The ratio of the total number of moles of the aromatic dicarboxylic acid compound and the aliphatic diol having 2 to 10 carbon atoms in the total number of moles of the carboxylic acid component and the alcohol component which are the raw material components of the condensation polymerization resin component is the composite resin From the viewpoint of enhancing crystallinity, it is preferably 75 to 100 mol%, more preferably 85 to 100 mol%, still more preferably 95 to 100 mol%.

  In the molar ratio of the carboxylic acid component to the alcohol component in the condensation polymerization resin component (carboxylic acid component / alcohol component), it is preferable that the amount of alcohol component is larger than that of the carboxylic acid component when increasing the molecular weight of the composite resin. The molar ratio is preferably 0.50 to 0.89, more preferably 0.70 to 0.85.

  The polycondensation reaction of the raw material monomer of the polycondensation resin component is carried out by polycondensation in an inert gas atmosphere at a temperature of about 180 to 250 ° C. in the presence of an esterification catalyst, a polymerization inhibitor, etc. Can be manufactured. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, titanium compounds such as titanium diisopropylate bistriethanolamate, and the esterification cocatalyst includes gallic acid. Etc. The amount of the esterification catalyst used is preferably 0.01 to 1.5 parts by weight, more preferably 0.1 to 1.0 parts by weight, based on 100 parts by weight of the total amount of the alcohol component, carboxylic acid component and both reactive monomer components. The amount of the esterification cocatalyst used is preferably 0.001 to 0.5 parts by weight, more preferably 0.01 to 0.1 parts by weight, with respect to 100 parts by weight of the total amount of the alcohol component, carboxylic acid component and both reactive monomer components.

  As a raw material monomer for the styrene resin component, styrene or styrene derivatives such as α-methylstyrene and vinyltoluene (hereinafter, styrene and styrene derivatives are collectively referred to as “styrene derivatives”) is used.

  The content of the styrene derivative is preferably 70% by weight or more in the raw material monomer of the styrene-based resin component from the viewpoint of improving the charge amount of the toner, suppressing fogging, and improving the solid followability and the halftone image density. More preferably, it is more than 90% by weight.

  Raw material monomers for styrene resin components used other than styrene derivatives include (meth) acrylic acid alkyl esters; ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; and halovinyls such as vinyl chloride. Vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic esters such as dimethylaminoethyl (meth) acrylate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; N-vinyl pyrrolidone N-vinyl compounds such as

  The raw material monomer of the styrene resin component used in addition to the styrene derivative can be used in combination of two or more. In the present specification, “(meth) acrylic acid” means acrylic acid and / or methacrylic acid.

  Among the raw material monomers of the styrene resin component used other than the styrene derivative, (meth) acrylic acid alkyl ester is preferable from the viewpoint of improving the low-temperature fixability of the toner. 1-22 are preferable from said viewpoint, and, as for carbon number of the alkyl group in (meth) acrylic-acid alkylester, 8-18 are more preferable. In addition, carbon number of this alkyl ester means carbon number derived from the alcohol component which comprises ester.

  Specific examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (iso or tertiary ) Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) decyl (meth) acrylate, (iso) stearyl (meth) acrylate, and the like. Here, “(iso or tertiary)” and “(iso)” mean that both of these groups are present and not present, and when these groups are not present Indicates normal. Further, “(meth) acrylate” indicates that both acrylate and methacrylate are included.

  The content of the (meth) acrylic acid alkyl ester is preferably 30% by weight or less in the raw material monomer of the styrenic resin component from the viewpoint of suppressing the fogging of the toner and improving the solid followability and the halftone image density. % By weight or less is more preferable, and 10% by weight or less is more preferable.

  A resin obtained by addition polymerization of a raw material monomer containing a styrene derivative and a (meth) acrylic acid alkyl ester is also referred to as a styrene- (meth) acrylic resin.

  The addition polymerization reaction of the raw material monomer of the styrenic resin component can be carried out by a conventional method, for example, in the presence of a polymerization initiator such as dicumyl peroxide, a crosslinking agent, etc., in the presence of an organic solvent or in the absence of a solvent. The temperature condition is preferably 110 to 200 ° C, more preferably 140 to 170 ° C.

  When an organic solvent is used in the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone or the like can be used. The amount of the organic solvent used is preferably about 10 to 50 parts by weight with respect to 100 parts by weight of the raw material monomer of the styrene resin component.

  The glass transition point (Tg) of the styrene resin component is preferably 60 to 130 ° C., more preferably from the viewpoint of improving low-temperature fixability of the toner, suppressing fogging, and improving solid followability and halftone image density. Is 80 to 120 ° C, more preferably 90 to 110 ° C.

Tg of styrene resin component is the empirical formula that predicts Tg called thermoadditive formula in the case of polymer, Fox formula (TGFox, Bull. Am. Physics Soc., Volume 1, No. 3, page 123 ( 1956)), the value obtained by calculation from the following formula (1) is used from the Tgn of the homopolymer of each monomer constituting each polymer.
1 / Tg = Σ (Wn / Tgn) (1)
(In the formula, Tgn is Tg represented by the absolute temperature of the homopolymer of each component, and Wn is the weight fraction of each component.)

  In the present specification, both reactive monomers described later are not included in the calculation of the content of the styrene resin component, and are not used in the calculation of Tg of the styrene resin component.

  For the calculation of the glass transition point (Tg) of the Fox formula used in the examples of the present invention, Tgn of styrene: 373 K (100 ° C.) and Tgn of 2-ethylhexyl acrylate: 223 K (-50 ° C.) are used.

  In the composite resin, the condensation polymerization resin and the styrenic resin component are preferably bonded directly or via a linking group. Examples of the linking group include a compound derived from an amphoteric monomer and a chain transfer agent described later, other resins, and the like.

  The composite resin is preferably in a state where the polycondensation resin component and the styrene resin component are dispersed in each other, and the dispersion state is determined by the following Tg of the composite resin measured by the method described in Examples. It can be evaluated by the difference from the calculated value of the Fox equation.

  That is, the composite resin in the present invention is a crystalline resin, but has an amorphous part derived from a styrene resin component and a condensation polymerization resin component, and has a Tg and a shrinkage derived from the styrene resin component. It has Tg derived from the polymerization resin component. The Tg of the styrene resin component and the Tg of the condensation polymerization resin component in the composite resin are values measured separately. As the degree of dispersion between the condensation polymerization resin component and the styrene resin component increases, When Tg approaches each other and the polycondensation resin component and the styrene resin component are dispersed to a substantially uniform state, both Tgs overlap and the measured value becomes almost one.

  Therefore, in a state where the styrene resin component and the condensation polymerization resin component are mutually dispersed, the Tg of the composite resin measured under the measurement conditions described later is different from the Tg calculated by the Fox equation of the styrene resin component. Value. Specifically, the absolute value of the difference between the glass transition point of the composite resin and the glass transition point calculated by the Fox formula of the styrene resin component in the composite resin is preferably 10 ° C or higher, more preferably 30 ° C or higher. Preferably, it is 50 ° C. or higher, more preferably 70 ° C. or higher. Generally, since the Tg of the condensation polymerization resin component is lower than the Tg of the styrene resin component, the measured value of Tg of the styrene resin component is often lower than the calculated Tg.

  Such a composite resin includes, for example, (1) a method in which a raw material monomer of a polycondensation resin component is polycondensed in the presence of a styrene resin having a carboxy group or a hydroxyl group, and the carboxy group or hydroxyl group has both reactivity described later. The thing derived from a monomer, a chain transfer agent, etc. can be used. (2) It can be obtained by a method such as addition polymerization of a raw material monomer of a styrene resin component in the presence of a condensation polymerization resin having a reactive unsaturated bond.

  The composite resin is added to the raw material monomer of the condensation polymerization resin component and the raw material monomer of the styrene resin component from the viewpoint of improving the low-temperature fixability of the toner, suppressing fogging, and improving the solid followability and the halftone image density. Further, a resin (hybrid resin) obtained by using both reactive monomers capable of reacting with both the raw material monomer of the condensation polymerization resin component and the raw material monomer of the styrene resin component is preferable. Therefore, when polymerizing the raw material monomer of the condensation polymerization resin component and the raw material monomer of the styrene resin component to obtain a composite resin, the condensation polymerization reaction and / or the addition polymerization reaction should be performed in the presence of both reactive monomers. Is preferred. As a result, the composite resin becomes a resin (hybrid resin) in which a condensation polymerization resin component and a styrene resin component are bonded via a structural unit derived from both reactive monomers, and the condensation polymerization resin component and the styrene resin component Becomes more finely and uniformly dispersed.

  From these, the composite resin is (a) a raw material monomer of a polycondensation resin component comprising an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms and a carboxylic acid component containing an aromatic dicarboxylic acid compound, It is a resin obtained by polymerizing a bi-reactive monomer capable of reacting with any of (a) a raw material monomer of a styrene resin component, and (c) a raw material monomer of a condensation polymerization resin component and a raw material monomer of a styrene resin component. Is preferred.

  As the both reactive monomers, at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group, preferably a hydroxyl group and / or in the molecule. A compound having a carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond is preferred, and by using such a bireactive monomer, the dispersibility of the resin that becomes the dispersed phase can be further improved. The both reactive monomers are preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and maleic anhydride, but from the viewpoint of the reactivity of the condensation polymerization reaction and the addition polymerization reaction. Therefore, acrylic acid, methacrylic acid or fumaric acid is more preferable. However, when used with a polymerization inhibitor, a polyvalent carboxylic acid such as fumaric acid may function as a raw material monomer for the condensation polymerization resin component.

  The amount of both reactive monomers used increases the dispersibility of the styrenic resin component and the condensation polymerization resin component, improves the low-temperature fixability of the toner, suppresses fogging and white background stains, and makes solid follow-up and halftone images. From the viewpoint of improving the concentration, 1 to 30 moles are preferable, 2 to 25 moles are more preferable, 2 to 20 moles are still more preferable, and styrene-based resin with respect to the total 100 moles of the alcohol component of the condensation polymerization resin component. 2 to 30 mol is preferable, 5 to 25 mol is more preferable, and 10 to 20 mol is more preferable with respect to 100 mol of the total raw material monomers (not including the polymerization initiator).

  Specifically, the composite resin is preferably produced by the following method. Both reactive monomers are used in addition polymerization reactions together with raw material monomers for styrenic resin components from the viewpoint of improving low-temperature fixability of toners, suppressing fogging and white background stains, and improving solid followability and halftone image density. Is preferred.

(i) A method in which the step (B) of the addition polymerization reaction with the raw material monomer and the both reactive monomers of the styrene resin component is performed after the step (A) of the condensation polymerization reaction with the raw material monomer of the condensation polymerization resin component. The step (A) is performed under a reaction temperature condition suitable for the condensation polymerization reaction, the reaction temperature is lowered, and the step (B) is performed under a temperature condition suitable for the addition polymerization reaction. It is preferable that the raw material monomer and the both reactive monomers of the styrene resin component are added to the reaction system at a temperature suitable for the addition polymerization reaction. Both reactive monomers react with the condensation polymerization resin component together with the addition polymerization reaction.
After the step (B), the reaction temperature is raised again, and if necessary, a raw material monomer of a polycondensation resin component such as a trivalent or higher that becomes a cross-linking agent is added to the polymerization system, and the polycondensation in the step (A). The reaction and reaction with both reactive monomers can be further advanced.

(ii) Method of performing the step (A) of the condensation polymerization reaction with the raw material monomer of the condensation polymerization resin component after the step (B) of the addition polymerization reaction with the raw material monomer of the styrene resin component and the amphoteric monomer. The step (B) is carried out under the reaction temperature conditions suitable for the addition polymerization reaction, the reaction temperature is raised, and the condensation polymerization reaction in the step (A) is carried out under the temperature conditions suitable for the condensation polymerization reaction. Both reactive monomers are involved in the condensation polymerization reaction as well as the addition polymerization reaction.
The raw material monomer of the condensation polymerization resin component may be present in the reaction system during the addition polymerization reaction, or may be added to the reaction system under temperature conditions suitable for the condensation polymerization reaction. In the former case, the progress of the condensation polymerization reaction can be controlled by adding an esterification catalyst at a temperature suitable for the condensation polymerization reaction.

(iii) A method in which the step (A) of the condensation polymerization reaction using the raw material monomer of the condensation polymerization resin component and the step (B) of the addition polymerization reaction using the raw material monomer and both reactive monomers of the styrene resin component are performed in parallel. In the method, the step (A) and the step (B) are carried out under reaction temperature conditions suitable for the addition polymerization reaction, the reaction temperature is increased, and a crosslinking agent is optionally added under temperature conditions suitable for the condensation polymerization reaction. It is preferable to add a raw material monomer of a polycondensation resin component having a valence of 3 or more to the polymerization system and further perform the polycondensation reaction in step (A). At that time, under a temperature condition suitable for the condensation polymerization reaction, a radical polymerization inhibitor can be added to advance only the condensation polymerization reaction. Both reactive monomers are involved in the condensation polymerization reaction as well as the addition polymerization reaction.

  In the above method (i), a prepolymerized polycondensation resin may be used in place of the step (A) of performing the polycondensation reaction. In the method (iii), when the step (A) and the step (B) are performed in parallel, the raw material monomer of the styrene resin component is contained in the mixture containing the raw material monomer of the condensation polymerization resin component. It is also possible to carry out the reaction by dropping the prepared mixture.

  The methods (i) to (iii) are preferably performed in the same container.

  In the composite resin, the weight ratio of the condensation polymerization resin component to the styrene resin component [condensation polymerization resin component / styrene resin component] (in the present invention, the raw material monomer of the condensation polymerization resin component is the raw material of the styrene resin component (The polymerization initiator is not included in the raw material monomer of the styrene resin component, which is the weight ratio to the monomer), that is, [total amount of raw material monomer of condensation polymerization resin component / total amount of raw material monomer of styrene resin component] The viewpoint that the continuous phase is a condensation polymerization resin and the disperse phase is a styrene resin improves the low-temperature fixability of the toner, suppresses fogging and white background stains, and improves the solid followability and halftone image density. From 50/50 to 95/5, 60/40 to 95/5 are preferable, 70/30 to 95/5 are more preferable, and 70/30 to 90/10 are more preferable. In the above calculation, the amount of both reactive monomers is included in the raw material monomer of the condensation polymerization resin component.

  In order to obtain a high molecular weight composite resin, the molar ratio of the carboxylic acid component and the alcohol component is adjusted as described above, the reaction temperature is increased, the amount of the catalyst is increased, the dehydration reaction is performed for a long time under reduced pressure, etc. The reaction conditions may be selected. Although a high-power motor can be used to stir the reaction raw material mixture to produce a high molecular weight crystalline resin, when the production equipment is not particularly selected, the raw material monomer is not used. A method of reacting with a reactive low-viscosity resin or a solvent is also an effective means.

  The softening point of the composite resin is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and even more preferably 100 ° C. or higher from the viewpoint of suppressing toner fogging and white background stain and improving solid followability and halftone image density. . Further, from the viewpoint of improving the low-temperature fixability of the toner, it is preferably 160 ° C. or lower, more preferably 140 ° C. or lower, and further preferably 135 ° C. or lower. Take these perspectives together. 80-160 degreeC is preferable, 90-140 degreeC is more preferable, 90-135 degreeC is further more preferable, 100-135 degreeC is still more preferable.

  In addition, the melting point of the composite resin (= maximum endothermic peak temperature) is preferably 80 ° C. or higher, and is preferably 90 ° C. or higher from the viewpoint of suppressing toner fogging and white background contamination and improving solid followability and halftone image density. Preferably, 100 ° C. or higher is more preferable. Further, from the viewpoint of improving the low-temperature fixability of the toner, 150 ° C. or lower is preferable, 140 ° C. or lower is preferable, and 130 ° C. or lower is more preferable. When these viewpoints are put together, it is preferably 80 to 150 ° C, more preferably 90 to 140 ° C, and further preferably 100 to 130 ° C.

  The softening point and melting point can be adjusted by adjusting the raw material monomer composition, polymerization initiator, molecular weight, catalyst amount, etc., or by selecting reaction conditions.

  The Tg of the composite resin is preferably −10 ° C. or higher, more preferably −5 ° C. or higher, and further preferably 0 ° C. or higher from the viewpoint of suppressing toner fogging and improving solid followability and halftone image density. Further, from the viewpoint of improving the low-temperature fixability of the toner and suppressing white background staining, it is preferably 50 ° C. or less, preferably 40 ° C. or less, and more preferably 30 ° C. or less. When these viewpoints are put together, Preferably it is -10-50 degreeC, More preferably, it is -5-40 degreeC, More preferably, it is 0-30 degreeC.

  In the present invention, the crystalline resin may contain a crystalline polyester or the like, but from the viewpoint of improving low-temperature fixability of the toner, suppressing fogging, and improving solid followability and halftone image density. The content of the composite resin in the crystalline resin is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 95% by weight or more in the crystalline resin.

  The content of the composite resin in the binder resin is preferably 5% by weight or more, more preferably 7% by weight or more, and further preferably 8% by weight or more from the viewpoint of improving the low-temperature fixability of the toner. In addition, from the viewpoint of suppressing toner fogging and improving solid followability and halftone image density, it is preferably 40% by weight or less, more preferably 30% by weight or less, further preferably 25% by weight or less, and more preferably 15% by weight or less. Is even more preferable. Taking these viewpoints together, 5 to 40% by weight is preferable, 5 to 30% by weight is more preferable, 7 to 25% by weight is further preferable, and 8 to 15% by weight is even more preferable.

  As the amorphous resin in the present invention, polyester, vinyl resin, epoxy resin, polycarbonate, polyurethane and the like are used. From the viewpoint of improving the low-temperature fixability of the toner, a polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component is preferable.

  The amorphous polyester used in the present invention improves the chargeability of the toner, and suppresses the embedding of the external additive into the toner base particles, thereby suppressing the fogging of the toner, and the solid followability and halftone. From the viewpoint of improving image density, the polyester may be obtained by polycondensation of an alcohol component containing 70 mol% or more of an alkylene oxide adduct of bisphenol A represented by the formula (I) and a carboxylic acid component. preferable.

  The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 80 to 100 mol%, still more preferably 90 to 100 mol%, from the same viewpoint as described above. .

  Examples of the alcohol component other than the alkylene oxide adduct of bisphenol A include polyhydric alcohols similar to those used for the crystalline resin.

  In the carboxylic acid component, the chargeability of the toner is improved and the embedding of the external additive into the toner base particles is suppressed, thereby suppressing the fogging of the toner and improving the solid followability and the halftone image density. In view of the above, it is preferable to contain the above-mentioned aromatic dicarboxylic acid compound, more preferably terephthalic acid. The content of the aromatic dicarboxylic acid compound is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, still more preferably 60 to 100 mol% in the carboxylic acid component.

  Examples of the polyvalent carboxylic acid compound that can be used other than the aromatic dicarboxylic acid compound include the same polyvalent carboxylic acid compounds as those used for the crystalline resin.

  Amorphous polyester, for example, is obtained by compressing an alcohol component and a carboxylic acid component at a temperature of about 180 to 250 ° C. in an inert gas atmosphere, if necessary, in the presence of an esterification catalyst, a polymerization inhibitor, or the like. It can be produced by polymerization. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate. Examples of the esterification promoter include gallic acid. The amount of the esterification catalyst used is preferably 0.01 to 1 part by weight, more preferably 0.1 to 0.6 part by weight, based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component. The amount of esterification promoter used is preferably 0.001 to 0.5 parts by weight, more preferably 0.01 to 0.1 parts by weight, based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  From the viewpoint of improving the transferability of the toner, the acid value of the amorphous polyester is preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less, and further preferably 20 mgKOH / g or less.

  In the present invention, the amorphous polyester having a polyester component obtained by condensation polymerization of an alcohol component and a carboxylic acid component includes not only the polyester but also a modified resin thereof.

  Examples of the polyester-modified resin include urethane-modified polyester in which polyester is modified with a urethane bond, epoxy-modified polyester in which polyester is modified with an epoxy bond, and a hybrid resin in which a polyester component and other resin components are combined. .

  The softening point of the amorphous resin is 70 ° C. or higher from the viewpoint of suppressing the embedding of the external additive into the toner base particles, thereby suppressing the fogging of the toner, and improving the solid followability and the halftone image density. Preferably, 90 ° C. or higher is more preferable. Further, from the viewpoint of improving the low-temperature fixability of the toner, it is preferably 180 ° C. or lower, and more preferably 150 ° C. or lower. When these viewpoints are put together, it is preferably 70 to 180 ° C, more preferably 90 to 150 ° C.

  Amorphous resin improves the low-temperature fixability of the toner and suppresses the embedding of external additives into the toner base particles, thereby suppressing toner fogging and improving the solid followability and halftone image density. From the viewpoint of making it, the softening point is preferably 5 ° C or higher, more preferably 10 to 50 ° C. From the viewpoint of improving the low-temperature fixability of the toner, the softening point of the low softening point polyester is preferably 80 to 125 ° C, more preferably 85 to 120 ° C. The softening point of the high softening point polyester is externally added. From the viewpoint of suppressing the embedding of the agent in the toner base particles, thereby suppressing the fogging of the toner, and improving the solid followability and the halftone image density, preferably 110 ° C. to 150 ° C., more preferably 115 to 145 ° C. It is. The weight ratio of the high softening point resin to the low softening point resin (high softening point resin / low softening point resin) suppresses embedding of the external additive in the toner base particles from the viewpoint of improving the low-temperature fixability of the toner. From the viewpoint of suppressing the fogging of the toner and improving the solid followability and the halftone image density, 10/90 to 90/10 is preferable, and 20/80 to 80/20 is more preferable.

  The Tg of the amorphous resin is preferably 45 ° C. or higher from the viewpoint of suppressing embedding of the external additive in the toner base particles, thereby suppressing the fogging of the toner, and improving the solid followability and the halftone image density. 55 ° C. or higher is more preferable. Further, from the viewpoint of improving the low-temperature fixability of the toner, it is preferably 80 ° C. or lower, and more preferably 75 ° C. or lower. Take these perspectives together. Preferably it is 45-80 degreeC, More preferably, it is 55-75 degreeC. In addition, Tg is a physical property peculiar to an amorphous phase, and is distinguished from the highest endothermic peak temperature.

  The weight ratio of crystalline resin to amorphous resin (crystalline resin / amorphous resin) improves the low-temperature fixability of the toner, suppresses fogging and white background stains, and improves solid follow-up and halftone image density. Therefore, 5/95 to 40/60 is preferable, 5/95 to 30/70 is more preferable, and 8/92 to 20/80 is further preferable.

  The toner base particles may contain a colorant, a release agent, a charge control agent and the like in addition to the binder resin.

  As the colorant, all of dyes and pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Isoindoline, Disazo Yellow and the like can be used. The content of the colorant is preferably 1 to 40 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The toner of the present invention may be either black toner or color toner.

  As the release agent, low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene polyethylene copolymer, aliphatic hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax and oxides thereof, carnauba wax, Examples thereof include montan wax, sazol wax and their deoxidized wax, ester waxes such as fatty acid ester wax, fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts and the like. These may be used alone or in admixture of two or more.

  The melting point of the release agent is preferably 60 to 160 ° C., more preferably 60 to 150 ° C., from the viewpoints of low-temperature fixability and offset resistance of the toner.

  The content of the release agent is preferably 10 parts by weight or less, more preferably 8 parts by weight or less, more preferably 7 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of preventing filming of the toner on the photoreceptor. The following is more preferable. Further, from the viewpoint of improving the high temperature offset resistance of the toner, 0.5 part by weight or more is preferable, 1.0 part by weight or more is more preferable, and 1.5 part by weight or more is further preferable. Therefore, taking these viewpoints together, 0.5 to 10 parts by weight is preferable, 1.0 to 8 parts by weight is more preferable, and 1.5 to 7 parts by weight is even more preferable. Further, from the viewpoint of oilless fixing of the toner, 3 parts by weight or more is preferable, 3.5 parts by weight or more is more preferable, and 4 parts by weight or more is more preferable. Therefore, taking these viewpoints together, it is preferably 3 to 10 parts by weight, more preferably 3.5 to 8 parts by weight, and even more preferably 4 to 7 parts by weight.

  The charge control agent is not particularly limited. Examples of the negative charge control agent include metal-containing azo dyes such as “Bontron S-28” (manufactured by Orient Chemical Co., Ltd.), “T-77” (Hodogaya Chemical Co., Ltd.). , "Bontron S-34" (Orient Chemical Co., Ltd.), "Eisenspiron Black TRH" (Hodogaya Chemical Co., Ltd.), etc .; copper phthalocyanine dyes, metal complexes of alkyl derivatives of salicylic acid, such as "Bontron" E-81 ”,“ Bontron E-84 ”,“ Bontron E-304 ”(manufactured by Orient Chemical Industry Co., Ltd.), etc .; Nitroimidazole derivatives; Boron benzylate complexes, such as“ LR-147 ”(manufactured by Nippon Carlit Non-metallic charge control agents such as “Bontron F-21”, “Bontron E-89” (manufactured by Orient Chemical Co., Ltd.), “T-8” (Hodogaya Chemical Co., Ltd.), “FCA- 2521NJ '', `` FCA-2508N '' (Fujikura Kasei Co., Ltd.) I can get lost.

  Examples of positively chargeable charge control agents include nigrosine dyes such as `` Bontron N-01 '', `` Bontron N-04 '', `` Bontron N-07 '' (above, manufactured by Orient Chemical Industries), `` CHUO CCA-3 '' ( Chuo Gosei Co., Ltd.), etc .; Triphenylmethane dyes containing tertiary amines as side chains; Quaternary ammonium salt compounds such as “Bontron P-51” (Orient Chemical Industries), “TP-415” And Tetsuya Chemical Industry Co., Ltd.), cetyltrimethylammonium bromide, “COPYCHARGEPXVP435” (manufactured by Cognis), and the like.

  The content of the charge control agent is not less than 0.1 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of making the toner charge amount appropriate, suppressing fogging, and improving solid followability and halftone image density. Preferably, it is 0.2 parts by weight or more. Further, from the viewpoint of making the charge amount of the toner appropriate and suppressing white background contamination, the amount is preferably 5 parts by weight or less, more preferably 3 parts by weight or less with respect to 100 parts by weight of the binder resin. That is, taking these viewpoints together, the content of the charge control agent is preferably 0.1 to 5 parts by weight and more preferably 0.2 to 3 parts by weight with respect to 100 parts by weight of the binder resin.

  The toner base particles of the present invention further include magnetic powder, fluidity improver, conductivity modifier, extender pigment, reinforcing filler such as fibrous substance, antioxidant, anti-aging agent, cleaning improver, etc. Additives may be contained as appropriate.

  In the present invention, the toner base particles can be produced by a known method such as a kneading and pulverizing method, a spray drying method, or a polymerization method. However, since the binder resin is excellent in pulverizing properties, the pulverized toner obtained by the kneading and pulverizing method is used. Is preferred. According to a general method of kneading and pulverization, for example, a raw material containing a binder resin and, if necessary, various additives such as a colorant is mixed with a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded. After cooling, coarsely pulverize using a hammer mill, etc., and further finely pulverize with a fine pulverizer or mechanical pulverizer using a jet stream, and with a classifier using a swirl stream or a classifier using the Coanda effect The toner base particles are obtained by classification to a desired particle size.

  Melting and kneading of raw materials can be performed using a known kneader such as a closed kneader, a single or twin screw extruder, a continuous open roll kneader, etc., but repeated kneading and use of a dispersion aid The continuous open roll type kneader equipped with a supply port and a kneaded product discharge port provided along the axial direction of the roll can efficiently and highly disperse the additive in the binder resin without the need for Is preferably used.

  The toner raw material is preferably mixed in advance using a Henschel mixer, a super mixer, etc., and then supplied to an open roll type kneader, and may be supplied to the kneader from one supply port. However, from the viewpoint of ease of operation and simplification of the apparatus, it is preferable to supply the kneader from one supply port.

  The continuous open roll type kneader refers to an open kneading unit that is not sealed, and can easily dissipate the kneading heat generated during kneading. Further, the continuous open roll type kneader is preferably a kneader equipped with at least two rolls, and the continuous open roll type kneader used in the present invention comprises two rolls having different peripheral speeds, That is, the kneading machine includes two rolls, a high rotation side roll having a high peripheral speed and a low rotation side roll having a low peripheral speed. In the present invention, from the viewpoint of dispersibility, it is desirable that the high rotation side roll is a heating roll and the low rotation side roll is a cooling roll.

  The temperature of the roll can be adjusted by, for example, the temperature of the heat medium passed through the inside of the roll, and each roll may be divided into two or more and the heat medium having different temperatures may be passed through each roll.

  The raw material charging side end temperature of the high rotation side roll is preferably 100 to 160 ° C, and the raw material charging side end temperature of the low rotation side roll is preferably 35 to 100 ° C.

  The high rotation side roll preferably has a set temperature difference between the raw material charging side end and the kneaded product discharge side end of 20 to 60 ° C. from the viewpoint of preventing detachment of the kneaded product from the roll. More preferably, it is 50 degreeC, and it is further more preferable that it is 30-50 degreeC. In the low rotation side roll, the difference in set temperature between the raw material charging side end and the kneaded product discharge side end is preferably 0 to 50 ° C., and 0 to 40 ° C. from the viewpoint of dispersibility of the release agent. It is more preferable that the temperature is 0 to 20 ° C.

  The peripheral speed of the high rotation side roll is preferably 2 to 100 m / min, more preferably 4 to 75 m / min, and further preferably 5 to 60 m / min. The peripheral speed of the low rotation side roll is preferably 1 to 90 m / min, more preferably 2 to 60 m / min, and further preferably 4 to 50 m / min. Further, the ratio of the peripheral speeds of the two rolls (low rotation side roll / high rotation side roll) is preferably 1/10 to 9/10, more preferably 3/10 to 8/10.

  The structure, size, material, etc. of the roll are not particularly limited, and the roll surface may be any of smooth, corrugated, uneven, etc., but in order to increase the kneading share, a plurality of roll surfaces are provided on the surface of each roll. It is preferable that the spiral groove is cut.

The volume median particle size (D ₅₀ ) of the toner base particles is preferably 5.0 μm or more from the viewpoint of maintaining fluidity during the external addition process. Further, from the viewpoint of maintaining the frictional force during the external addition treatment, 10.0 μm or less is preferable, and 9.0 μm or less is more preferable. In other words, from these viewpoints taken together, D ₅₀ of the toner mother particles is preferably 5.0~10.0μm, 5.0~9.0μm is more preferable. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  The toner of the present invention can be obtained by performing an external addition treatment for attaching an external additive to the toner base particles and externally adding the external additive to the toner base particles.

  The toner of the present invention contains melamine resin fine particles as an external additive. That is, the toner of the present invention is obtained by externally adding an external additive containing melamine resin fine particles to the toner base particles containing the binder resin, the release agent and the colorant.

  In the present invention, the melamine-based resin fine particles are those having a triazine skeleton, and include resin fine particles composed of a condensate of a compound having a triazine skeleton and an aldehyde. Examples of the compound having a triazine skeleton include melamine and benzoguanamine. Among these, melamine is preferable, and examples of aldehydes include formaldehyde, acetaldehyde, propionaldehyde, and glyoxal. Among these, formaldehyde is preferable. Accordingly, melamine-based resin fine particles suitable in the present invention include melamine / formaldehyde condensation-polymerized resin fine particles.

  The average particle size of the melamine resin fine particles is 0.1 μm or more, preferably 0.15 μm or more, from the viewpoint of suppressing the fogging of the toner and improving the solid followability and the halftone image density, and the solid followability of the toner. From the standpoint of improving whiteness and suppressing white background stains, it is 0.8 μm or less, preferably 0.6 μm or less, and more preferably 0.4 μm or less. That is, when these viewpoints are put together, it is 0.1-0.8 micrometer, Preferably it is 0.1-0.6 micrometer, More preferably, it is 0.15-0.4 micrometer. Here, the average particle size refers to the average primary particle size, and the particle size (average value of major axis and minor axis) of 500 particles is measured from a scanning electron microscope (SEM) photograph, and the average value is averaged. The particle size.

  Examples of commercially available melamine-based resin fine particles include Eposter S and Eposter S6 (manufactured by Nippon Shokubai Co., Ltd.).

  The addition amount of the melamine resin fine particles is 0.03 parts by weight or more with respect to 100 parts by weight of the toner base particles and 0.05 parts by weight or more from the viewpoint of suppressing the fogging of the toner and improving the solid followability and the halftone image density. Is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more. From the viewpoint of improving the halftone image density of the toner and suppressing white background staining, it is 1.0 part by weight or less, preferably 0.8 part by weight or less, more preferably 0.6 part by weight or less, and further preferably 0.5 part by weight or less. That is, when these viewpoints are put together, it is 0.03-1.0 weight part, 0.05-0.8 weight part is preferable, 0.1-0.6 weight part is more preferable, 0.2-0.5 weight part is further more preferable.

  Further, the toner of the present invention can be used in combination with an external additive other than melamine resin fine particles. From the viewpoint of suppressing the fogging and white background stain of the toner, and improving the solid followability and the halftone image density. The content of the resin fine particles is preferably from 0.3 to 70% by weight, more preferably from 1 to 50% by weight, more preferably from 4 to 40% by weight, and even more preferably from 8 to 30% by weight in all external additives.

  Examples of other external additives include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as resin fine particles other than melamine resin fine particles. Among these, silica is preferably used in combination from the viewpoints of preventing melamine resin fine particles from being buried, suppressing toner fogging, and improving solid followability and halftone image density, and silica having an average particle diameter of less than 20 nm. And 20 nm or more of silica are more preferred. When two types of silica are used in combination, the difference in average particle diameter is preferably 10 nm or more. In addition, in this invention, the average particle diameter of a silica is measured by the method as described in the below-mentioned Example.

  Although the toner of the present invention is suitable for speeding up and downsizing of the apparatus, even if the toner is used in an image forming apparatus of a non-magnetic one-component developing system that receives a lot of mechanical and thermal stress, Is suppressed, and good solid followability and halftone image density can be maintained. Accordingly, the present invention provides an image forming method using the toner of the present invention in a non-magnetic one-component developing device. Furthermore, the toner of the present invention can be suitably used in an oilless non-magnetic one-component developing device from the same viewpoint. The oilless fixing is a method using a fixing device having a heat roll fixing device that does not include an oil supply device. The oil supply device has an oil tank and has a mechanism for quantitatively applying oil to the surface of the heat roll, as well as a device having a mechanism for bringing a roll pre-impregnated with oil into contact with the heat roll, etc. including.

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample was heated at a heating rate of 6 ° C / min, and a 1.96 MPa load was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. . The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Maximum peak temperature and melting point of resin endotherm]
Using a differential scanning calorimeter (Q-100 Japan, Q-100), weigh 0.01 to 0.02 g of the sample into an aluminum pan and cool it from room temperature to 0 ° C at a rate of 10 ° C / min. Then, it was left still for 1 minute. Thereafter, the measurement was carried out at a heating rate of 50 ° C./min. Of the endothermic peaks observed, the peak temperature on the highest temperature side was defined as the highest endothermic peak temperature. If the maximum peak temperature is within 20 ° C of the softening point, the peak temperature is taken as the melting point.

[Glass transition point of amorphous resin]
Using a differential scanning calorimeter (Q-100 Japan, Q-100), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and decrease the temperature from that temperature. Cooled to 0 ° C at 10 ° C / min. Next, the sample was measured at a heating rate of 10 ° C./min. The glass transition point is defined as the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Glass transition point of crystalline resin (composite resin)]
Using a differential scanning calorimeter (Q-100 Japan, Q-100), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and decrease the temperature from that temperature. Cooled to -80 ° C at 100 ° C / min. Next, the sample was measured in a modulated mode at a heating rate of 1 ° C./min. The glass transition point is defined as the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Acid value of the resin]
Measured by the method of JIS K0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Melting point of release agent]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature was raised to 200 ° C, and the sample was cooled to 0 ° C at a temperature drop rate of 10 ° C / min. The maximum peak temperature of heat of fusion is taken as the melting point.

[Average particle diameter of external additive]
The average particle size refers to the average primary particle size, and the particle size (average value of major axis and minor axis) of 500 particles is measured from a scanning electron microscope (SEM) photograph, and the average value is referred to as the average particle size. To do.

[Volume Median Particle Size (D ₅₀ ) of Toner Base Particles]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) is dissolved in the electrolyte so as to have a concentration of 5% by weight.
Dispersion conditions: 10 mg of a measurement sample was added to 5 ml of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 25 ml of the electrolyte was added, and further dispersed for 1 minute with an ultrasonic disperser. Prepare sample dispersion.
Measurement conditions: The sample dispersion is added to 100 ml of the electrolytic solution so that the particle size of 30,000 particles can be measured in 20 seconds, and 30,000 particles are measured. Determine the median particle size (D ₅₀ ).

[Production Examples of Crystalline Resins (Composite Resins) A to F]
Put a specified amount of the raw material monomer of the polycondensation resin component other than acrylic acid, which is the amphoteric reaction monomer shown in Table 1, into a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. Heat to 160 ° C. to dissolve. A premixed solution of styrene, dicumyl peroxide and acrylic acid was added dropwise with a dropping funnel over 1 hour. Stirring was continued for 1 hour while maintaining at 170 ° C. to polymerize styrene and acrylic acid, and then unreacted styrene and acrylic acid were removed at 8.3 kPa for 1 hour. Thereafter, 40 g of tin (II) 2-ethylhexanoate and 3 g of gallic acid were added, the temperature was raised to 210 ° C., and the reaction was carried out for 8 hours. The reaction was further carried out at 8.3 kPa for 1 hour to obtain crystalline resins A to F. Table 1 shows the resin physical properties of the obtained crystalline resin.

[Production Example of Crystalline Resin (Polyester) G]
2,974 g of 1,6-hexanediol, 972 g of 1,4-butanediol, 5498 g of terephthalic acid, 40 g of tin (II) 2-ethylhexanoate, and 3 g of gallic acid The mixture was placed in a 10-liter four-necked flask equipped and allowed to react at 180 ° C. for 4 hours under a nitrogen atmosphere, and further heated to 210 ° C. for 10 hours. Furthermore, reaction was performed at 8.3 kPa for 1 hour, and crystalline resin G was obtained. The obtained crystalline resin G had a softening point of 126 ° C., a maximum endothermic peak temperature of 113 ° C. and a value of [softening point / endothermic maximum peak temperature] of 1.12.

[Production Example 1 of Amorphous Polyester]
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 1286 g, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 2218 g, terephthalic acid 1603 g, 2-ethylhexane 10 g of tin (II) oxide and 2 g of gallic acid were placed in a 10-liter four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple, and the reaction rate was 90% at 230 ° C. in a nitrogen atmosphere. Then, the reaction was continued at 8.3 kPa until the softening point reached 111 ° C. to obtain amorphous polyester (resin a). Resin a had a glass transition point of 69 ° C., a softening point of 111 ° C., a maximum endothermic peak temperature of 71 ° C., a ratio of [softening point / maximum endothermic peak temperature] of 1.6, and an acid value of 3.2 mgKOH / g. . The reaction rate means a value of the amount of produced reaction water / theoretical product water amount × 100.

[Production Example 2 of Amorphous Polyester]
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 3486 g, Polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 3240 g, Terephthalic acid 1881 g, Tetrapropenyl anhydride 269 g of acid, 30 g of tin (II) 2-ethylhexanoate and 2 g of gallic acid were placed in a 10-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple. After reacting at 90 ° C. until the reaction rate reached 90%, the reaction was allowed to proceed at 8.3 kPa for 1 hour. Next, 789 g of trimellitic anhydride was added, and a reaction was performed at 220 ° C. until the softening point reached 122 ° C. to obtain an amorphous polyester (resin b). Resin b had a glass transition point of 64 ° C., a softening point of 122 ° C., a maximum endothermic peak temperature of 65 ° C., a [softening point / maximum endothermic peak temperature] value of 1.9, and an acid value of 18.9 mgKOH / g. .

[Examples 1-8 and Comparative Examples 1-10]
A predetermined amount of resin a, resin b, crystalline resin, and negative charge control agent “Bontron E-304” (manufactured by Orient Chemical Co., Ltd.) 0.2 parts by weight, carnauba wax C1 (manufactured by Kato Yoko Co., Ltd.) 3 parts by weight of a melting point: 88 ° C., 3 parts by weight of paraffin wax “HNP-9” (manufactured by Nippon Seisaku Co., Ltd., melting point: 75 ° C.), a colorant “ECB-301” (manufactured by Dainichi Seika Co., Ltd., phthalocyanine blue : 3)) 5.0 parts by weight were mixed for 1 minute using a Henschel mixer and then melt-kneaded under the following conditions.

  A continuous two-open roll kneader “NIDEX” (manufactured by Mitsui Mining Co., Ltd., roll outer diameter: 14 cm, effective roll length: 80 cm) was used. The operating conditions of the continuous two open roll type kneader are: high rotation side roll (front roll) peripheral speed 75r / min (32.97m / min), low rotation side roll (back roll) peripheral speed 50r / min (21.98m) / min), the roll gap at the end of the kneaded product supply port was 0.1 mm. The heating medium temperature and cooling medium temperature in the roll are 135 ° C. on the raw material input side of the high rotation side roll and 90 ° C. on the kneaded material discharge side, 35 ° C. on the raw material input side of the low rotation side roll and 35 ° C. on the kneaded material discharge side. there were. The feed rate of the raw material mixture was 10 kg / hour, and the average residence time was about 6 minutes.

The obtained kneaded product is cooled to 20 ° C. or lower while being rolled with a cooling roll, and the cooled melt-kneaded product is coarsely pulverized to 3 mm with a Rotoplex (manufactured by Toa Machinery Co., Ltd.). -400 "was triturated with (Alpine Co.), and classified by a rotor type classifier" TTSP "(Alpine Co.), the volume-median particle size (D ₅₀₎ to obtain toner mother particles of 8.0 .mu.m. A predetermined amount of resin fine particles shown in Table 2 and hydrophobic silica “RY50” (manufactured by Nippon Aerosil Co., Ltd., average particle size: 40 nm) 1.0 part by weight of the toner base particles 100 parts by weight, hydrophobic silica “R972” (Nippon Aerosil Co., Ltd.) Manufactured, average particle size: 16 nm) 0.5 part by weight was mixed with a Henschel mixer (Mitsui Mining Co., Ltd.) at 1500 r / min for 1 minute to obtain a toner.

Test Example 1 [low temperature fixability]
Mount toner on the non-magnetic one-component developing device "OKI MICROLINE 5400" (Oki Data Co., Ltd.) and adjust the toner adhesion amount to 0.45 ± 0.03mg / cm ² to produce a solid image of 4.1cm x 13.0cm at Fuji Xerox Printed on J paper manufactured by Office Supply. A solid image was taken out before passing through the fixing machine to obtain an unfixed image. Fix the obtained unfixed image at a fixing speed of 240 mm / sec using an external fixing machine modified from the OKI MICROLINE 3010 (Oki Data) fixing machine, setting the temperature of the fixing roll to 100 ° C. It was. Thereafter, the fixing roll temperature was set to 105 ° C., and the same operation was performed. This was performed while increasing the temperature up to 200 ° C by 5 ° C.

After attaching mending tape (manufactured by Sumitomo 3M) to the image fixed at each temperature, it is sufficient to place a cylindrical weight (25.5g / cm ² ) of 5cm in diameter, 3cm in height and 500g in weight. A tape was attached to the fixed image. Thereafter, the mending tape was slowly peeled off from the fixed image, and the optical reflection density of the image after tape peeling was measured using a reflection densitometer “RD-915” (manufactured by Macbeth). The optical reflection density is also measured for the image before applying the tape in advance, and the temperature of the fixing roll whose ratio to the value (after tape peeling / before tape application) first exceeds 90% is set as the minimum fixing temperature. Fixability was evaluated. The results are shown in Table 2.

Test Example 2 [Photoconductor fog]
A non-magnetic one-component developer "OKI MICROLINE 710" (Oki Data Co., Ltd.) remodeled to a linear speed of 240 mm / sec (equivalent to A4 vertical 40 sheets / min) is mounted with toner, with a pattern that gives a print rate of 5%. After printing 10,000 sheets, a solid white image was printed on J paper made by Fuji Xerox Office Supply Co., and the printer power was turned off during the printing. The toner on the surface of the photoconductor is attached to a mending tape (manufactured by Sumitomo 3M), the color density is measured using a color difference meter “CR-221” (manufactured by Minolta), and the color density of the tape before the toner is attached. The difference was determined and fog was evaluated. The smaller the value, the better the fog. The results are shown in Table 2.

Test Example 3 [Solid Follow-up]
After printing 10,000 sheets as in Test Example 2, two black solid images were printed on J paper manufactured by Fuji Xerox Office Supply. The reflection density meter RD-915 (manufactured by Macbeth Co., Ltd.) is used to measure the image density (ID ₁ ) of the central part 5 cm from the top of the first printed sheet and the image density (ID ₂ ) of the central part 5 cm from the bottom of the second printed sheet. The solid followability was evaluated based on the difference in image density between the two. The smaller the value, the better the solid followability. The results are shown in Table 2.

Test Example 4 [Halftone image density]
After printing 10,000 sheets as in Test Example 2, print a halftone image (2 x 2 images) using J paper manufactured by Fuji Xerox Office Supply, and use a colorimeter (Spectroeye manufactured by Gretag-Macbeth) The image density of the central portion of 10 cm from the top of the printed paper was measured under the conditions of light emission with a standard light source D50, an observation field of view 2 °, and a density standard DIN NB with an absolute white standard. An image density of 0.80 or more and less than 1.10 is acceptable. The results are shown in Table 2.

Test Example 5 [white background dirt]
After printing 10,000 sheets in the same manner as in Test Example 2, using J paper manufactured by Fuji Xerox Office Supply Co., Ltd., and printing an entire white solid image, the presence or absence of image smear on the paper was visually confirmed. The results are shown in Table 2.

  From the above results, the toners of Examples 1 to 8 were compared with the toner of Comparative Example 1 in which no melamine resin fine particles were blended and the external addition amount and average particle size of the melamine resin fine particles were outside the predetermined range. Examples 2 to 4, toners of Comparative Examples 5 and 6 using resin particles other than melamine resin, and Comparative Examples in which the weight ratio of the polycondensation resin component and the styrene resin component of the composite resin is outside the predetermined range 7-9, in comparison with the toner of Comparative Example 10 containing no crystalline resin, it is good in any evaluation of low-temperature fixability, photoreceptor fog, solid followability, halftone image density, and white background stains. I understand that.

  The toner of the present invention is suitably used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, and the like.

Claims (6)

  A toner comprising toner base particles containing a binder resin and an external additive, wherein the binder resin comprises a crystalline resin and an amorphous resin, and the crystalline resin is a fat having 2 to 10 carbon atoms. A polycondensation resin component obtained by polycondensation of an alcohol component containing an aromatic diol and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and a composite resin comprising a styrene resin component, The weight ratio of the condensation polymerization resin component to the styrene resin component in the composite resin (condensation polymerization resin component / styrene resin component) is 50/50 to 95/5, and the external additive has an average particle size of 0.1 to A toner comprising 0.8 μm of melamine resin fine particles, wherein the content of the melamine resin fine particles is 0.03 to 1.0 part by weight with respect to 100 parts by weight of toner base particles.   A raw material monomer of a polycondensation resin component, wherein the composite resin comprises (a) an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms and a carboxylic acid component containing an aromatic dicarboxylic acid compound; 2. A resin obtained by polymerizing a raw material monomer of a resin component, and (c) a bi-reactive monomer capable of reacting with any of a raw material monomer of a polycondensation resin component and a raw material monomer of a styrene resin component. The toner described.   The toner according to claim 2, wherein the amount of the both reactive monomers used is 2 to 30 moles with respect to a total of 100 moles of raw material monomers of the styrenic resin component.   The toner according to claim 1, wherein the absolute value of the difference between the glass transition point of the composite resin and the glass transition point calculated by the Fox formula of the styrene resin component in the composite resin is 10 ° C. or more.   An image forming method in which the toner according to claim 1 is used in a non-magnetic one-component developing device.   6. The image forming method according to claim 5, wherein the non-magnetic one-component developing device is an oilless non-magnetic one-component developing device.