Electrostatic charge image development toner

Abstract

To provide an electrostatic charge image development toner excellent in low-temperature fixability and thermostability of an image.SOLUTION: An electrostatic charge image development toner includes a binder resin and a coloring agent. The binder resin includes an amorphous polyester resin and a crystalline polyester resin. The amorphous polyester resin includes an amorphous polyester resin A being a polycondensation product of a raw material monomer including an aromatic hydroxycarboxylic acid-based compound of 50-100 mol%. A content of the amorphous polyester resin A is 3-25 mass% in the binder resin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an electrostatic charge image developing toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

Background Art

[0002] In recent years, with the increasing use of printers for industrial printing applications, the demand for an electrostatic charge image developing toner having excellent low-temperature fixability and image heat resistance has been increasing.

[0003] On the other hand, from the viewpoints of low-temperature fixability and heat-resistant storage stability, a toner has been studied which contains at least a binder resin and a release agent, and the binder resin contains a side-chain type liquid crystalline polyester resin having a liquid crystalline expression site having an aromatic hydroxycarboxylic acid as a basic skeleton in a side chain (see Patent Document 1).

[0004] Further, a polyester resin using an aromatic hydroxycarboxylic acid is also used as fine particles insoluble in a polymer and its monomer (see Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Conventionally, a crystalline polyester resin has been used as a binder resin effective for low-temperature fixability, but there is a problem that the image heat resistance decreases due to insufficient crystallization of the crystalline polyester resin after printing.

[0007] The present invention relates to an electrostatic charge image developing toner having excellent low-temperature fixability and image heat resistance.

Means for Solving the Problems

[0008] The present invention is an electrostatic charge image developing toner containing a binder resin and a colorant, wherein the binder resin contains an amorphous polyester resin and a crystalline polyester resin, and the amorphous polyester resin contains an amorphous polyester resin A which is a polycondensate of raw material monomers containing 50 mol% or more and 100 mol% or less of an aromatic hydroxycarboxylic acid-based compound, and the content of the amorphous polyester resin A is 3% by mass or more and 25% by mass or less in the binder resin.

Effects of the Invention

[0009] The electrostatic charge image developing toner of the present invention exhibits excellent effects in improving low-temperature fixability and image heat resistance.

Modes for Carrying Out the Invention

[0010] The electrostatic charge image developing toner of the present invention (hereinafter also simply referred to as "toner") contains a binder resin and a colorant, and has a major feature in that it contains an amorphous polyester resin A obtained by using a predetermined amount of an aromatic hydroxycarboxylic acid-based compound and a crystalline polyester resin as the binder resin. The reason why the toner of the present invention is effective in improving low-temperature fixability and image heat resistance is not clear, but it is presumed as follows. The following mechanism is a presumption and is not limited thereto.

[0011] The molecular chains of conventional amorphous polyester resins formed by polycondensation of diols and dicarboxylic acids have alternating orientations of ester groups between monomers, that is, -CO-O- and -O-CO- are arranged alternately, and the intermolecular aromatic ring interaction is weak. In contrast, the molecular chains of amorphous polyester resins formed by polycondensation of aromatic hydroxycarboxylic acid-based compounds have a unidirectional orientation of ester groups and regular molecular arrangements. Due to the strong aromatic ring interaction, the molecular mobility during melting is low, and amorphous polyester resin A acts as a crystallization nucleating agent for crystalline polyester resins. As a result, the recrystallization rate of the crystalline polyester resin is improved, and the image heat resistance is improved while maintaining the low-temperature fixing property. As a crystallization nucleating agent for general crystalline polyester resins, for example, fatty acid bisamides are used. However, fatty acid bisamides have high hygroscopicity and poor chargeability. In contrast, amorphous polyester resin A obtained using aromatic hydroxycarboxylic acid-based compounds has low hygroscopicity and good chargeability due to strong aromatic ring interaction.

[0012] The binder resin contains an amorphous polyester resin and a crystalline polyester resin, and the amorphous polyester resin contains amorphous polyester resin A, which is a polycondensate of a raw material monomer containing an aromatic hydroxycarboxylic acid-based compound. Amorphous polyester resin A is preferably a resin having liquid crystallinity, which passes through a liquid crystal phase having a regular arrangement structure of molecular chains during melting in the transition from the amorphous phase to the crystalline phase.

[0013] Examples of aromatic hydroxycarboxylic acid-based compounds include benzoic acid derivatives such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid, and 4-hydroxy-3,5-dimethoxybenzoic acid; naphthoic acid derivatives such as 6-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, and 3-hydroxy-2-naphthoic acid; phenylacetic acid derivatives such as 2-hydroxy-2-phenylacetic acid and hydroxydiphenylacetic acid; and acetylated products thereof. Among these, from the viewpoint of image heat resistance, it is preferable to contain 4-hydroxybenzoic acid. The content of 4-hydroxybenzoic acid in the aromatic hydroxycarboxylic acid-based compound is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, and preferably 80 mol% or less, more preferably 70 mol% or less, still more preferably 60 mol% or less.

[0014] The content of the aromatic hydroxycarboxylic acid-based compound is 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more in the raw material monomers, and is 100 mol% or less, preferably 95 mol% or less, more preferably 90 mol% or less.

[0015] As the raw material monomers other than the aromatic hydroxycarboxylic acid-based compound, an alcohol component and a carboxylic acid component are preferable.

[0016] As the alcohol component, an aromatic diol is preferable.

[0017] Examples of the aromatic diol include hydroquinone, catechol, resorcinol, an alkylene oxide adduct of bisphenol A represented by the following formula (I), etc. Among these, hydroquinone is preferable.

[0018] The content of the alcohol component, preferably the aromatic diol, is preferably 2 mol% or more, more preferably 4 mol% or more, still more preferably 6 mol% or more in the raw material monomers, and is preferably 20 mol% or less, more preferably 17 mol% or less, still more preferably 14 mol% or less.

[0019] As the carboxylic acid component, an aromatic dicarboxylic acid-based compound is preferable.

[0020] Examples of the aromatic dicarboxylic acid-based compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, alkyl esters of these acids having 1 to 3 carbon atoms, etc.

[0021] The content of the carboxylic acid component, preferably an aromatic dicarboxylic acid-based compound, in the raw material monomers is preferably 2 mol% or more, more preferably 4 mol% or more, still more preferably 6 mol% or more, and preferably 20 mol% or less, more preferably 17 mol% or less, still more preferably 14 mol% or less.

[0022] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid-based compound.

[0023] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and the carboxylic acid component.

[0024] The equivalent ratio of the carboxy group to the hydroxyl group (COOH group / OH group) in the raw material monomers of the amorphous polyester resin A is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less, from the viewpoint of adjusting the softening point of the polyester resin.

[0025] The amorphous polyester resin A preferably contains a structural unit derived from an aromatic hydroxycarboxylic acid-based compound in the main chain. When producing the amorphous polyester resin A, it is preferable to subject the raw material monomers to a polycondensation reaction at once. For example, the raw material monomers are in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and further, if necessary, in the presence of a cocatalyst, a polymerization inhibitor, etc., preferably at a temperature of 120°C or higher, more preferably 140°C or higher, and preferably 270°C or lower, more preferably 250°C or lower, to carry out polycondensation to produce an amorphous polyester resin containing a structural unit derived from an aromatic hydroxycarboxylic acid-based compound in the main chain.

[0026] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolamineate). The amount of the esterification catalyst used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the raw material monomer (when using the acetylating agent described below, based on 100 parts by mass of the total of the raw material monomer and the acetylating agent, the same applies hereinafter). Examples of the co-catalyst for the esterification catalyst include gallic acid and its hydrates. The amount of the co-catalyst used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, based on 100 parts by mass of the raw material monomer. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, based on 100 parts by mass of the raw material monomer.

[0027] In the present invention, from the viewpoint of increasing the reactivity of the aromatic hydroxycarboxylic acid-based compound, the amorphous polyester resin A preferably has an acetyl group at its terminal. For this purpose, it is preferable to use an acetylated product of the aromatic hydroxycarboxylic acid-based compound or to carry out the polycondensation reaction of the raw material monomers in the presence of an acetylating agent such as acetic anhydride or acetyl chloride to acetylate at least a part of the aromatic hydroxycarboxylic acid-based compound.

[0028] When it has an acetyl group, the amount of the acetyl group in the amorphous polyester resin A can be adjusted by the amount of the acetylated product of the aromatic hydroxycarboxylic acid-based compound or the acetylating agent used. The molar ratio (CH3CO group / OH group) of the acetyl group to the hydroxyl group in the amorphous polyester resin A is preferably 50 / 50 or more, more preferably 70 / 30 or more, still more preferably 90 / 5 or more, and even more preferably 95 / 5 or more, and it is even more preferable that all the hydroxyl groups are acetylated. Incidentally, the amount of the acetyl group in the amorphous polyester resin A can be determined from the values of the acid value and the hydroxyl value.

[0029] In the present invention, the polyester resin may be a polyester resin modified to such an extent that its properties are not substantially impaired. Examples of the modified polyester resin include polyester resins grafted or blocked with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, a urethane-modified polyester resin obtained by extending a polyester resin with a polyisocyanate compound is preferable.

[0030] From the viewpoint of heat-resistant storage stability, the softening point of the amorphous polyester resin A is preferably 90°C or higher, more preferably 100°C or higher, still more preferably 110°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 150°C or lower, more preferably 145°C or lower, still more preferably 140°C or lower.

[0031] Incidentally, the crystallinity of the resin is represented by a crystallinity index defined by the ratio of the softening point to the maximum peak temperature of endotherm measured by a differential scanning calorimeter, that is, the value of [softening point / maximum peak temperature of endotherm]. The amorphous resin is a resin in which no endothermic peak is observed, or when an endothermic peak is observed, the crystallinity index exceeds 1.4, preferably exceeds 1.5, more preferably is 1.6 or more, or is less than 0.6, preferably 0.5 or less. On the one hand, the crystalline resin has a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and is a resin of 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and production conditions (for example, reaction temperature, reaction time, cooling rate), etc. The maximum peak temperature of endotherm refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In the crystalline resin, the maximum peak temperature of endotherm is taken as the melting point.

[0032] From the viewpoint of heat-resistant storage stability, the glass transition temperature of the amorphous polyester resin A is preferably 50°C or higher, more preferably 60°C or higher, still more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 95°C or lower, more preferably 91°C or lower, still more preferably 87°C or lower.

[0033] From the viewpoint of image heat resistance, the weight average molecular weight of the amorphous polyester resin A is preferably 2,000 or more, more preferably 3,000 or more, still more preferably 3,500 or more, still more preferably 4,000 or more, and from the viewpoint of low-temperature fixability, it is preferably 10,000 or less, more preferably 9,000 or less, still more preferably 8,000 or less, still more preferably 7,000 or less.

[0034] The content of the amorphous polyester resin A is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more in the amorphous polyester resin, and is preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less.

[0035] The content of the amorphous polyester resin A is 3% by mass or more in the binder resin, preferably 5% by mass or more, more preferably 7% by mass or more, and from the viewpoint of low-temperature fixability, it is 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less.

[0036] Also, from the viewpoint of image heat resistance, the content of the amorphous polyester resin A is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, still more preferably 80 parts by mass or more, and preferably 220 parts by mass or less, more preferably 180 parts by mass or less, still more preferably 140 parts by mass or less with respect to 100 parts by mass of the crystalline polyester resin.

[0037] The amorphous polyester resin preferably further contains an amorphous polyester resin B which is a polycondensate of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing an aromatic dicarboxylic acid compound.

[0038] As the alkylene oxide adduct of bisphenol A, the formula (I):

[0039]

Chemical formula

[0040] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y represent the average number of moles of alkylene oxide added, and are positive numbers respectively. The value of the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, still more preferably 4 or less) The compound represented by the formula is preferred. Examples of the alkylene oxide adduct of bisphenol A represented by the formula (I) include polyoxypropylene adduct of 2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene adduct of 2,2-bis(4-hydroxyphenyl)propane, etc. It is preferable to use one or more of these.

[0041] The content of the alkylene oxide adduct of bisphenol A represented by formula (I) is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 100 mol% in the alcohol component from the viewpoint of heat storage stability.

[0042] Examples of other alcohol components include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, neopentyl glycol; and polyhydric alcohols having a valency of 3 or more such as bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, trimethylolpropane.

[0043] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0044] The content of the aromatic dicarboxylic acid compound is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 100 mol% in the carboxylic acid component from the viewpoint of heat storage stability.

[0045] Examples of other carboxylic acid components include aliphatic dicarboxylic acids such as fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, glutaric acid, adipic acid, sebacic acid; polyvalent carboxylic acids having a valency of 3 or more such as trimellitic acid, pyromellitic acid; anhydrides of these acids; and alkyl esters of these acids having 1 to 3 carbon atoms.

[0046] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0047] The equivalent ratio of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less, from the viewpoint of adjusting the softening point of the polyester resin.

[0048] The polycondensation reaction conditions of the alcohol component and the carboxylic acid component of the amorphous polyester resin B are the same as those of the amorphous polyester resin A, except that a suitable reaction temperature is 160°C or higher, more preferably 180°C or higher, and 250°C or lower, more preferably 240°C or lower.

[0049] The softening point of the amorphous polyester resin B is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, from the viewpoint of charge stability, and preferably 170°C or lower, more preferably 160°C or lower, still more preferably 150°C or lower, from the viewpoint of low-temperature fixability.

[0050] Note that the amorphous polyester resin B may be composed of resins having different softening points, from the viewpoints of low-temperature fixability and fixing width. The difference in the softening points of the two resins is preferably 10°C or more, more preferably 20°C or more, and preferably 60°C or less, more preferably 40°C or less.

[0051] The softening point of the amorphous polyester resin with a higher softening point (resin BH) is preferably 100°C or higher, more preferably 110°C or higher, still more preferably 120°C or higher, from the viewpoint of fixing width, and preferably 170°C or lower, more preferably 160°C or lower, still more preferably 150°C or lower, from the viewpoint of low-temperature fixability.

[0052] Also, from the viewpoint of charge stability, the softening point of the amorphous polyester resin (resin BL) with a lower softening point is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 130°C or lower, more preferably 125°C or lower, still more preferably 120°C or lower.

[0053] The mass ratio of resin BH to resin BL (resin BH / resin BL) is preferably 10 / 90 or more, more preferably 20 / 80 or more, still more preferably 30 / 70 or more, and preferably 90 / 10 or less, more preferably 80 / 20 or less, still more preferably 75 / 25 or less.

[0054] From the viewpoint of hot offset resistance, the weight average molecular weight of the amorphous polyester resin BH is preferably 60,000 or more, more preferably 80,000 or more, still more preferably 100,000 or more, and from the viewpoint of low-temperature fixability, it is preferably 250,000 or less, more preferably 200,000 or less, still more preferably 150,000 or less.

[0055] From the viewpoint of hot offset resistance, the weight average molecular weight of the amorphous polyester resin BL is preferably 4,000 or more, more preferably 4,500 or more, still more preferably 5,000 or more, and from the viewpoint of low-temperature fixability, it is preferably 7,000 or less, more preferably 6,500 or less, still more preferably 6,000 or less.

[0056] From the viewpoint of heat storage stability, the glass transition temperature of the amorphous polyester resin B is preferably 40°C or higher, more preferably 50°C or higher, and from the viewpoint of charge stability, it is preferably 80°C or lower, more preferably 70°C or lower.

[0057] The content of the amorphous polyester resin B is preferably 75% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, and preferably 96% by mass or less, more preferably 94% by mass or less, still more preferably 92% by mass or less in the amorphous polyester resin.

[0058] The mass ratio of the amorphous polyester resin A to the amorphous polyester resin B (amorphous polyester resin A / amorphous polyester resin B) is preferably 3 / 97 or more, more preferably 7 / 93 or more, and preferably 25 / 75 or less, more preferably 20 / 80 or less, still more preferably 15 / 85 or less.

[0059] The content of the amorphous polyester resin B is preferably 55% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, and preferably 90% by mass or less, more preferably 88% by mass or less, still more preferably 85% by mass or less in the binder resin.

[0060] The total content of the amorphous polyester resin A and the amorphous polyester resin B is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass in the amorphous polyester resin.

[0061] As the crystalline polyester resin, a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component is preferred.

[0062] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, etc. Among these, from the viewpoint of low-temperature fixing property, ethylene glycol or 1,6-hexanediol is preferred.

[0063] The number of carbon atoms of the aliphatic diol is 2 or more, and from the viewpoint of low-temperature fixability, it is preferably 12 or less, more preferably 6 or less, and still more preferably 4 or less.

[0064] The content of the aliphatic diol is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably 95 mol% or more in the alcohol component, and is 100 mol% or less. When the alcohol component contains a monoalcohol, it is preferably 98 mol% or less, more preferably 95 mol% or less.

[0065] Examples of other alcohol components include alkylene oxide adducts of bisphenol A, aromatic diols such as bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and polyhydric alcohols such as trimethylolpropane having 3 or more valences.

[0066] The carboxylic acid component preferably contains an aliphatic dicarboxylic acid-based compound.

[0067] Examples of the aliphatic dicarboxylic acid-based compound include succinic acid (number of carbon atoms: 4), fumaric acid (number of carbon atoms: 4), adipic acid (number of carbon atoms: 6), suberic acid (number of carbon atoms: 8), azelaic acid (number of carbon atoms: 9), sebacic acid (number of carbon atoms: 10), dodecanedioic acid (number of carbon atoms: 12), tetradecanedioic acid (number of carbon atoms: 14), succinic acid having an alkyl group or alkenyl group in the side chain, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0068] The number of carbon atoms of the aliphatic dicarboxylic acid-based compound is preferably 4 or more, more preferably 8 or more, still more preferably 10 or more, and still more preferably 12 or more from the viewpoint of hydrophobicity, and is preferably 16 or less, more preferably 14 or less from the viewpoint of low-temperature fixability. Here, when the aliphatic dicarboxylic acid-based compound is an alkyl ester, the number of carbon atoms of the alkyl group is not included in the above number of carbon atoms.

[0069] The content of the aliphatic dicarboxylic acid-based compound is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less in the carboxylic acid component. When the carboxylic acid component contains a monocarboxylic acid-based compound, it is preferably 98 mol% or less, more preferably 95 mol% or less.

[0070] Examples of other carboxylic acid components include aromatic dicarboxylic acid-based compounds such as phthalic acid, isophthalic acid, and terephthalic acid, and polyvalent carboxylic acid-based compounds such as trimellitic acid and pyromellitic acid.

[0071] Furthermore, from the viewpoint of image heat resistance, it is preferable that the alcohol component and / or carboxylic acid component of the crystalline polyester resin contain a monofunctional monomer.

[0072] Examples of the monofunctional monomer contained in the alcohol component include aliphatic monoalcohols such as caprylic alcohol, capric alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

[0073] Examples of the monofunctional monomer contained in the carboxylic acid component include aliphatic monocarboxylic acids such as caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and aliphatic monocarboxylic acid-based compounds such as alkyl esters in which the alkyl group of these acids has 1 to 3 carbon atoms.

[0074] From the viewpoint of improving hydrophobicity, the monofunctional monomer is preferably an aliphatic monocarboxylic acid-based compound and / or an aliphatic monoalcohol.

[0075] From the viewpoint of hydrophobicity, the number of carbon atoms of the aliphatic monoalcohol is preferably 6 or more, more preferably 9 or more, still more preferably 10 or more, and even more preferably 12 or more. From the viewpoint of low-temperature fixability, it is preferably 24 or less, more preferably 23 or less, and still more preferably 22 or less.

[0076] From the viewpoint of hydrophobicity, the number of carbon atoms of the aliphatic monocarboxylic acid compound is preferably 6 or more, more preferably 9 or more, still more preferably 10 or more, and from the viewpoint of low-temperature fixability, it is preferably 24 or less, more preferably 23 or less, still more preferably 22 or less. Here, when the aliphatic monocarboxylic acid compound is an alkyl ester, the number of carbon atoms of the alkyl group is not included in the above number of carbon atoms.

[0077] The content of the monofunctional monomer is preferably 2 mol% or more, more preferably 3 mol% or more in the total amount of the alcohol component and the carboxylic acid component, and from the viewpoint of low-temperature fixability, it is preferably 10 mol% or less, more preferably 8 mol% or less, still more preferably 6 mol% or less.

[0078] The equivalent ratio of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.7 or more, more preferably 0.8 or more from the viewpoint of heat-resistant storage stability, and from the viewpoint of low-temperature fixability, it is preferably 1.2 or less, more preferably 1.1 or less.

[0079] The polycondensation reaction conditions of the crystalline polyester resin between the alcohol component and the carboxylic acid component are the same as those of the amorphous polyester resin A except that the suitable reaction temperature is 120°C or higher, more preferably 180°C or higher, and 230°C or lower, more preferably 220°C or lower.

[0080] From the viewpoint of heat-resistant storage stability, the softening point of the crystalline polyester resin is preferably 50°C or higher, more preferably 65°C or higher, still more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 120°C or lower, more preferably 110°C or lower.

[0081] From the viewpoint of heat-resistant storage stability, the melting point of the crystalline polyester resin is preferably 60°C or higher, more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 130°C or lower, more preferably 120°C or lower.

[0082] From the viewpoint of hot offset resistance, the weight average molecular weight of the crystalline polyester resin is preferably 10,000 or more, more preferably 12,000 or more, still more preferably 14,000 or more. From the viewpoint of low-temperature fixing property, it is preferably 24,000 or less, more preferably 22,000 or less, still more preferably 20,000 or less.

[0083] From the viewpoint of low-temperature fixing property, the content of the crystalline polyester resin in the binder resin is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less.

[0084] The mass ratio of the crystalline polyester resin to the amorphous polyester resin (crystalline polyester resin / amorphous polyester resin) is preferably 4 / 96 or more, more preferably 6 / 94 or more, still more preferably 8 / 92 or more, and is preferably 20 / 80 or less, more preferably 17 / 83 or less, still more preferably 14 / 86 or less.

[0085] Examples of other binder resins include amorphous polyester resins other than amorphous polyester resins A and B, vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins.

[0086] The total content of the amorphous polyester resin and the crystalline polyester resin in the binder resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass.

[0087] The content of the binder resin in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, and is preferably less than 100% by mass, more preferably 98% by mass or less, still more preferably 95% by mass or less.

[0088] As the colorant, dyes, pigments, magnetic materials, etc. that are used as colorants for toners can be used. For example, carbon black, copper phthalocyanine pigment, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. can be mentioned. In the present invention, the toner may be either a black toner or a color toner. In the present invention, a colorant having an aromatic ring is preferable and a copper phthalocyanine pigment is more preferable because the interaction with the aromatic ring of the amorphous polyester resin A is strong and the effect of enhancing the image density is more remarkable.

[0089] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and still more preferably 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0090] In addition to the binder resin and the colorant, the toner of the present invention may contain additives such as a release agent, a charge control agent, magnetic powder, a fluidity improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver.

[0091] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and their oxides; ester waxes such as carnauba wax, montan wax, and their deacidified waxes, fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc. These can be used alone or in combination of two or more.

[0092] From the viewpoint of the transferability of the toner, the melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 160°C or lower, more preferably 140°C or lower, still more preferably 120°C or lower, and even more preferably 110°C or lower.

[0093] From the viewpoints of the low-temperature fixability and offset resistance of the toner and the dispersibility in the binder resin, the content of the release agent is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, still more preferably 1.5 part by mass or more, with respect to 100 parts by mass of the binder resin, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, still more preferably 7 parts by mass or less.

[0094] The charge control agent is not particularly limited, and may contain either a positive-chargeable charge control agent or a negative-chargeable charge control agent.

[0095] Examples of the positive-chargeable charge control agent include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", "Bontron N-07", "Bontron N-09", "Bontron N-11" (manufactured by Orient Chemical Industries, Ltd.); triphenylmethane dyes containing a tertiary amine in the side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries, Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant); polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industries, Ltd.); imidazole derivatives such as "PLZ-2001", "PLZ-8001" (manufactured by Shikoku Kasei Kogyo Co., Ltd.); styrene-acrylic resins such as "FCA-701PT", "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.).

[0096] In addition, examples of the negatively charged charge control agent include metal-containing azo dyes such as "Vari Fast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", "Bontron S-36" (manufactured by Orient Chemical Industries, Ltd.), "Eisen Spiron Black TRH", "T-77" (manufactured by Hodogaya Chemical Co., Ltd.), etc.; metal compounds of benzoic acid compounds such as "LR-147", "LR-297" (manufactured by Nippon Carlit Co., Ltd.), etc.; metal compounds of salicylic acid compounds such as "Bontron E-81", "Bontron E-84", "Bontron E-88", "Bontron E-304" (manufactured by Orient Chemical Industries, Ltd.), "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.), etc.; copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives, etc.; and organometallic compounds, etc.

[0097] From the viewpoint of the charging stability of the toner, the content of the charge control agent is preferably 0.01 part by mass or more, more preferably 0.2 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0098] The toner of the present invention may be a toner obtained by any known method such as a melt-kneading method, an emulsion aggregation method, a polymerization method, etc. However, from the viewpoint of more significantly exhibiting the effects of the present invention, a pulverized toner by a melt-kneading method is preferred. By the melt-kneading method, high dispersion of the crystalline polyester resin in the amorphous polyester resin becomes possible. In the case of a pulverized toner by a melt-kneading method, for example, raw materials such as a binder resin, a colorant, a release agent, a charge control agent, etc. are uniformly mixed by a mixer such as a Henschel mixer, and then melt-kneaded by a closed kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc., and can be manufactured by cooling, pulverizing, and classifying.

[0099] In the toner of the present invention, in order to improve transferability, it is preferable to use an external additive. Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles, and two or more kinds may be used in combination. Among these, silica is preferable, and from the viewpoint of the transferability of the toner, hydrophobic silica subjected to a hydrophobization treatment is more preferable.

[0100] Examples of the hydrophobization treatment agent for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0101] From the viewpoints of the chargeability, fluidity, and transferability of the toner, the average particle diameter of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0102] The external addition treatment by mixing toner particles and an external additive can be performed according to a conventional method, and a mixer such as a Henschel mixer can be used.

[0103] From the viewpoints of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more, and even more preferably 0.3 part by mass or more with respect to 100 parts by mass of the toner particles before being treated with the external additive, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

[0104] The volume median particle diameter (D 50 ) of the toner of the present invention is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. In this specification, the volume median particle diameter (D 50It means the particle size at which the cumulative volume frequency calculated by volume fraction reaches 50% when calculated from the smaller particle size. When the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is defined as the volume median particle size of the toner.

[0105] The toner of the present invention can be used in an image forming apparatus of a one-component development system or a two-component development system as a one-component development toner as it is or as a two-component development toner used by mixing with a carrier.

Examples

[0106] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. Physical properties such as resins can be measured by the following methods.

[0107] 〔Softening point of resin〕 Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating 1 g of the sample at a heating rate of 6 °C / min, a load of 1.96 MPa is applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. Plot the plunger drop amount of the flow tester against the temperature, and the temperature at which half of the sample flows out is defined as the softening point.

[0108] 〔Maximum peak temperature of endotherm of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample into an aluminum pan, cool it from room temperature (25 °C) to 0 °C at a cooling rate of 10 °C / min, and maintain it at 0 °C for 1 minute. Then, measure it at a heating rate of 10 °C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is defined as the maximum peak temperature of endotherm.

[0109] 〔Glass transition temperature of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan, heated from room temperature (25°C) to 200°C at a heating rate of 10°C / min, and then cooled from that temperature to 0°C at a cooling rate of 10°C / min. Next, the sample is heated at a heating rate of 10°C / min, and the endothermic peak is measured. The temperature at the intersection of the extension line of the baseline below the maximum peak temperature of the endotherm and the tangent line showing the maximum slope from the rising part of the peak to the apex of the peak is defined as the glass transition temperature.

[0110] [Weight-average molecular weight (Mw) of the resin] The molecular weight distribution is measured by gel permeation chromatography (GPC) method and the weight-average molecular weight is determined by the following method. (1) Preparation of sample solution The sample is dissolved in a solvent (amorphous resin containing an aromatic hydroxycarboxylic acid compound: pentafluorophenol / chloroform = 1 / 2 (mass ratio), amorphous resin not containing an aromatic hydroxycarboxylic acid compound: tetrahydrofuran, crystalline resin: chloroform) at 40°C so that the concentration becomes 0.5 g / 100 mL. Then, this solution is filtered using a PTFE type membrane filter "DISMIC-25JP" (manufactured by Toyo Roshi Kaisha, Ltd.) with a pore size of 0.20 μm to remove insoluble components, and a sample solution is obtained. (2) Molecular weight measurement Using the following measuring apparatus and analytical column, an eluent (amorphous resin containing an aromatic hydroxycarboxylic acid compound: pentafluorophenol / chloroform = 1 / 2 (mass ratio), amorphous resin not containing an aromatic hydroxycarboxylic acid compound: tetrahydrofuran, crystalline resin: chloroform) is flowed at a flow rate of 1 mL per minute, and the column is stabilized in a constant temperature bath at 40°C. 100 μL of the sample solution is injected there and measurement is carried out. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time uses several types of monodisperse polystyrene (A-500 (5.0×10 2 ) manufactured by Tosoh Corporation, A-1000 (1.01×10 3 ), A-2500 (2.63×10 3)、A-5000 (5.97×10 3 )、F-1 (1.02×10 4 )、F-2 (1.81×10 4 )、F-4 (3.97×10 4 )、F-10 (9.64×10 4 )、F-20 (1.90×10 5 )、F-40 (4.27×10 5 )、F-80 (7.06×10 5 )、F-128 (1.09×10 6 )) are used as standard samples. The values in parentheses indicate the molecular weights. Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation) Analysis column: TSKgel GMH XL + TSKgel G3000H XL (manufactured by Tosoh Corporation)

[0111] 〔Melting point of the mold release agent〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 - 0.02 g of the sample into an aluminum pan, heat it up to 200 °C at a heating rate of 10 °C / min, and then cool it down to -10 °C at a cooling rate of 5 °C / min from that temperature. Next, heat the sample up to 180 °C at a heating rate of 10 °C / min and measure it. The maximum peak temperature of the endotherm observed from the resulting melting endotherm curve is taken as the melting point of the mold release agent.

[0112] 〔Average particle diameter of the external additive〕 The average particle diameter refers to the number-average particle diameter. Measure the particle diameters (average value of the major axis and minor axis) of 500 particles from a scanning electron microscope (SEM) photograph, and take their number-average value.

[0113] 〔Volume median diameter (D 50 ) of the toner〕 · Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) · Aperture diameter: 50 μm · Analysis software: "Multisizer (registered trademark) III Version 3.51" (manufactured by Beckman Coulter, Inc.) · Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) · Dispersion liquid: A solution prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to adjust to 5% by mass · Dispersion conditions: Add 10 mg of the measurement sample to 5 mL of the dispersion liquid, disperse it with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W) for 1 minute, then add 25 mL of the electrolyte, and further disperse it with the ultrasonic disperser for 1 minute to prepare a sample dispersion liquid. · Measurement conditions: By adding the sample dispersion liquid to 100 mL of the electrolyte, adjust to a concentration at which the particle size of 30,000 particles can be measured in 20 seconds, then measure 30,000 particles, and determine the volume median diameter (D 50 ) from its particle size distribution.

[0114] Resin production example 1 Put the raw material monomers, acetylating agent, and esterification catalyst shown in Table 1 into a 10-liter four-necked flask equipped with a thermometer, a stainless-steel stirring rod, a dehydrating tube, a cooling tube, and a nitrogen introduction tube, and heat it up to 150°C in a mantle heater under a nitrogen atmosphere over 1 hour. Then, hold at 150°C for 30 minutes, then heat up to 210°C, and hold at 210°C for 30 minutes. Then, heat up to 240°C over 1 hour, and further carry out the reaction at 40 kPa until the desired softening point is reached to obtain an amorphous polyester resin (resins A1 to A7).

[0115]

Table 1

[0116] Resin production example 2 The raw material monomers and esterification catalyst shown in Table 2 were placed in a 10-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a water removal tube, a cooling tube, and a nitrogen introduction tube, and heated in a mantle heater under a nitrogen atmosphere to 235°C over 2 hours. Then, a polycondensation reaction was carried out at 235°C for 8 hours, and the reaction was further carried out at 8 kPa until the desired softening point was reached, to obtain an amorphous polyester resin (resin BL1).

[0117] Resin Production Example 3 The raw material monomers and esterification catalyst other than adipic acid and trimellitic anhydride shown in Table 2 were placed in a 10-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a water removal tube, a cooling tube, and a nitrogen introduction tube, and heated in a mantle heater under a nitrogen atmosphere to 235°C over 2 hours. Then, after confirming that the reaction rate reached 95% or more at 235°C, it was cooled to 180°C. Then, adipic acid and trimellitic anhydride shown in Table 2 were added, and the temperature was raised to 220°C over 2 hours. Then, after reacting at 220°C for 1 hour, the reaction was carried out at 8 kPa until the desired softening point was reached, to obtain an amorphous polyester resin (resin BH1). Here, the reaction rate refers to the value of (mol of generated reaction water volume) / (mol of theoretical generated water volume)×100.

[0118]

Table 2

[0119] Resin Production Example 4 The raw material monomers and esterification catalyst shown in Table 3 were placed in a 10-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a water removal tube, a cooling tube, and a nitrogen introduction tube, and kept at 140°C for 1 hour in a mantle heater under a nitrogen atmosphere, then heated from 140°C to 200°C at 10°C / h, and then a polycondensation reaction was carried out at 200°C for 1 hour, and the reaction was further carried out at 200°C and 8 kPa until the desired softening point was reached, to obtain crystalline polyester resins (resins C1, C2).

[0120]

Table 3

[0121] Examples 1 to 9 and Comparative Examples 1 to 3 100 parts by mass of the binder resin shown in Table 4, 1 part by mass of the negative charge control agent "Bontron E-81" (manufactured by Orient Chemical Industries, Ltd.), 5 parts by mass of the copper phthalocyanine pigment "Pigment blue 15:3" (manufactured by Dainichi Seika Kogyo Co., Ltd.), and 2 parts by mass of the release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 80°C) were thoroughly mixed with a Henschel mixer. Then, using a co-rotating twin-screw extruder with a total kneading length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm, melt-kneading was performed at a roll rotation speed of 200 r / min and a heating temperature inside the roll of 100°C. The supply rate of the mixture was 20 kg / h, and the average residence time was about 18 seconds. After cooling and coarsely pulverizing the obtained melt-kneaded product, it was pulverized with a jet mill and classified to obtain toner particles with a volume median diameter (D 50 ) of 8 μm.

[0122] To 100 parts by mass of the obtained toner particles, 1 part by mass of hydrophobic silica "AEROSIL NAX 50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: HMDS, average particle diameter: about 30 nm) was added as an external additive and mixed with a Henschel mixer to obtain toner.

[0123] Reference Example 1 A toner was obtained in the same manner as in Example 1, except that 5 parts by mass of the crystal nucleating agent shown in Table 4 was used instead of Resin A, and the amount of Resin BL1 used was changed to 55 parts by mass.

[0124] Test Example 1 [Low-temperature Fixing Property] The toner was mounted on a non-magnetic one-component developing device "OKI MICROLINE 5400" (manufactured by Oki Electric Industry Co., Ltd.), and the toner adhesion amount was 0.45 ± 0.03 mg / cm 2Adjusted to obtain a solid image of 4.1 cm × 13 cm, and printed it on "J paper" (manufactured by Fujifilm Business Innovation). The solid image was taken out before passing through the fuser to obtain an unfixed image. The obtained unfixed image was fixed on an external fuser with the fuser roll temperature set to 100°C and a fixing speed of 240 mm / sec using an external fuser obtained by modifying the fuser of "Microline3010" (manufactured by Oki Electric Industry Co., Ltd.). Subsequently, the fuser roll temperature was set to 105°C, and the same operation was performed. While increasing the temperature by 5°C up to 200°C, the unfixed image was fixed at each temperature to obtain a fixed image. After attaching a mending tape (manufactured by Sumitomo 3M Limited) to the images fixed at each temperature, a weight on a 500 g cylinder was placed on it to sufficiently attach the tape to the fixed image. Then, 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 of the image before attaching the tape in advance was also measured, and the temperature of the fuser roll at which the ratio ([reflection density after tape peeling / reflection density before tape attachment] × 100) first exceeded 90% was defined as the minimum fixing temperature and used as an index for low-temperature fixability. The results are shown in Table 4.

[0125] Test Example 2 [Image Heat Resistance] The toner was mounted on a device obtained by modifying the fuser of a copying machine "AR-505" (manufactured by Sharp Corporation) so that fixing outside the device was possible, and a printed matter was obtained in an unfixed state (printing area: 2 cm × 12 cm, toner adhesion amount: 0.5 mg / cm 2 ). Then, using an external fixing device (fixing speed 300 mm / sec) obtained by modifying "OKIMICROLINE3010" (manufactured by Oki Electric Industry Co., Ltd.), it was adjusted so that the total fixing pressure became 40 kgf, the temperature of the fuser roll was set to the minimum fixing temperature + 15°C, and the unfixed printed matter was fixed. The paper used for printing was "CopyBond SF-70NA" (manufactured by Sharp Corporation, 75 g / m 2 ). The fixed images were overlapped, and 100 g / cm 2Under a load, at a temperature of 60°C and a humidity of 50%, it was left standing for 1 day, and the reflection image density of the printed matter when peeled off after 1 day was measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, light irradiation conditions; standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). The average value of the measured values at any three points on the image was taken as the image density, and the change rate of the image density before and after image overlay [((image density after overlay) / (image density before overlay)) × 100] was calculated. The results are shown in Table 4. The smaller the change amount of the image density before and after overlay, the better the heat resistance of the image.

[0126] Test Example 3 [Charge stability] The toner was left standing for 72 hours in an environment with a temperature of 25°C and a relative humidity of 50%. 0.6 g of the standing toner and 19.4 g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle diameter: 90 μm) were placed in a 50 mL polyethylene container, and mixed at 250 r / min using a ball mill. The charge amount of the toner after mixing for 60 seconds and 3600 seconds was measured using a Q / M meter (manufactured by EPPING) by the following method. After a predetermined mixing time, a specified amount of the mixture of toner and carrier was put into the cell attached to the Q / M meter, and only the toner was suctioned for 90 seconds through a sieve with an opening of 32 μm (made of stainless steel, twill weave, wire diameter: 0.0035 mm). The voltage change on the carrier generated at that time was monitored, and the value of [total charge amount (μC) after 90 seconds / amount of toner suctioned (g)] was taken as the charge amount (μC / g). The ratio of the charge amount after 60 seconds of mixing time to the charge amount after 3600 seconds of mixing time (charge amount after 3600 seconds of mixing time / charge amount after 60 seconds of mixing time) was calculated. The results are shown in Table 4. The closer the ratio of the charge amount is to 1, the better the charge stability.

[0127]

Table 4

[0128] From the above results, it can be seen that compared with Comparative Examples 1 to 3, the toners of Examples 1 to 9 have good low-temperature fixing properties and image heat resistance. In addition, in Reference Example 1 in which a fatty acid bisamide generally used as a crystal nucleating agent for crystalline polyester resins was used instead of the amorphous polyester resin A in the present invention, although the low-temperature fixing properties and image heat resistance are good, it can be seen that there is a significant lack of charge stability.

Industrial Applicability

[0129] The electrostatic charge image developing toner of the present invention is suitably used for developing latent images formed in electrostatic charge image developing methods, electrostatographic recording methods, electrostatic printing methods, and the like.

Claims

1. An electrostatic charge image developing toner containing a binder resin and a colorant, wherein the binder resin contains an amorphous polyester resin and a crystalline polyester resin, the amorphous polyester resin contains an amorphous polyester resin A which is a polycondensate of raw material monomers containing 50 mol% or more and 100 mol% or less of an aromatic hydroxycarboxylic acid-based compound, and the content of the amorphous polyester resin A is 3% by mass or more and 25% by mass or less in the binder resin. An electrostatic charge image developing toner.

2. The electrostatic charge image developing toner according to claim 1, wherein in the amorphous polyester resin A, the main chain contains a structural unit derived from an aromatic hydroxycarboxylic acid-based compound.

3. The electrostatic charge image developing toner according to claim 1 or 2, wherein the amorphous polyester resin A has an acetyl group at the terminal.

4. The electrostatic charge image developing toner according to any one of claims 1 to 3, wherein the aromatic hydroxycarboxylic acid-based compound contains 4-hydroxybenzoic acid.

5. The electrostatic charge image developing toner according to any one of claims 1 to 4, wherein the colorant contains a copper phthalocyanine pigment.

6. The electrostatic charge image developing toner according to any one of claims 1 to 5, wherein the crystalline polyester resin is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component.

7. The electrostatic charge image developing toner according to any one of claims 1 to 6, which is a pulverized toner.

Images