JP7089944B2 - Image formation method - Google Patents

Description

The present invention relates to a method for forming an image by an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., and a resin used in the method.

In the field of electrophotographic, with the development of electrophotographic systems, there is a demand for the development of toners for electrophotographics that can achieve high image quality and high speed.

In Patent Document 1, in a toner containing at least a binder resin and a wax, the binder resin contains at least a resin A having a polyester unit composed of an alcohol component containing an aromatic diol as a main component and an aliphatic diol as a main component. The polyester resin B and the aliphatic conjugated diene resin C obtained by shrink-polymerizing the alcohol component and the acid component containing an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid as a main component are contained in the binder resin. The content a (mass%) of the resin A is 50% by mass or more and 98% by mass or less, the content of the resin B in the binder resin is b (mass%), and the content of the resin C is c (mass). %), The relationship is "0.02 ≦ b / a <1.00" and "0.05 ≦ c / b ≦ 0.30". According to the toner, it is described that both low temperature fixing resistance, blocking resistance, high temperature offset resistance, and high temperature and high humidity conditions can suppress fluctuations in image density when used at a low printing ratio.

Japanese Unexamined Patent Publication No. 2010-210997

After forming an unfixed toner image on a print medium, heat is applied to fix the toner image on the print medium, but excellent low-temperature fixability is required in order to cope with high image quality and high speed. On the other hand, if the low temperature fixing property is improved, there is a problem that the hot offset resistance and durability are impaired.
The toner of Patent Document 1 cannot be said to be a toner excellent in all of low temperature fixing property, hot offset resistance, and durability.
The present invention relates to an image forming method and a resin used in the method, which are excellent in low temperature fixing property, hot offset resistance, and durability.

The present invention relates to the following [1] to [2].
[1] An alcohol component containing an ethylene oxide adduct of bisphenol A of 30 mol% or more and 80 mol% or less and 1,4-butanediol of 20 mol% or more and 70 mol% or less, and a carboxylic acid component containing an aromatic dicarboxylic acid. A step of forming an unfixed toner image on a print medium with a toner containing an amorphous polyester resin (A) which is a polycondensate of the above.
The fixing process of applying heat to the unfixed toner image to fix it,
Image forming method having.
[2] An alcohol component containing an ethylene oxide adduct of bisphenol A of 30 mol% or more and 80 mol% or less and 1,4-butanediol of 20 mol% or more and 70 mol% or less, and a carboxylic acid component containing an aromatic dicarboxylic acid. Acryid polyester resin which is a polycondensate of.

According to the present invention, it is possible to provide an image forming method and a resin used in the image forming method, which are excellent in low temperature fixing property, hot offset resistance, and durability.

FIG. 1 is a schematic configuration diagram of an image forming apparatus.

[Image formation method]
The image forming method of the present invention (hereinafter, also simply referred to as "image forming method") is
Polycondensation of an alcohol component containing 30 mol% or more and 80 mol% or less of an ethylene oxide adduct of bisphenol A and 20 mol% or more and 70 mol% or less of 1,4-butanediol and a carboxylic acid component containing an aromatic dicarboxylic acid. A step of forming an unfixed toner image on a print medium with a toner containing an amorphous polyester resin (A) (hereinafter, also simply referred to as "resin (A)"), which is a product.
The fixing process of applying heat to the unfixed toner image to fix it,
Have.
According to the above configuration, by using the toner containing the resin (A), it is possible to provide an image forming method having excellent low temperature fixing property, hot offset resistance, and durability, and a resin used in the method. Can be done.

The reason is not clear, but it can be considered as follows.
Since the ethylene oxide adduct of bisphenol A and 1,4-butanediol have relatively high molecular structure symmetry, they show strong orientation, and it is considered that the polyester resin containing them has a large intermolecular interaction. .. Therefore, the resin (A) has a small decrease in melt viscosity and can maintain a high viscosity even at a high temperature equal to or higher than the glass transition temperature. That is, it is considered that even a resin having a low glass transition temperature has a high melt viscosity at a high temperature, and can achieve both low temperature fixability and hot offset resistance. When the resin (A) is below the glass transition temperature, the molecular interaction is strong, and the resin (A) is a very hard resin, so that it is considered to be excellent in durability.

Definitions of various terms in the present specification are shown below.
Whether the resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined by the ratio of the softening point of the resin to the maximum endothermic temperature (softening point (° C.) / maximum endothermic temperature (° C.)) in the measuring method described in Examples described later. The crystalline resin is a resin having a crystallinity index of 0.6 or more and less than 1.4, preferably 0.7 or more, more preferably 0.9 or more, and preferably 1.2 or less. The amorphous resin is a resin having a crystallinity index of 1.4 or more, or less than 0.6, preferably 1.5 or more, or 0.5 or less, more preferably 1.6 or more, or 0.5 or less. The crystallinity index can be appropriately adjusted depending on the type and ratio of the raw material monomers, and the production conditions such as reaction temperature, reaction time, and cooling rate. The maximum endothermic temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. The crystallinity index can be calculated from the values obtained by the method for measuring the softening point of the resin and the maximum endothermic temperature described in the examples.
In the specification, the carboxylic acid component of the polyester resin includes not only the exemplified compound, but also an anhydrate that decomposes during the reaction to generate an acid, and an alkyl ester of each carboxylic acid (alkyl group having 1 or more carbon atoms 3). The following) is also included.
In the specification, the "binding resin" means a resin component contained in a toner containing an amorphous polyester resin (A), an amorphous polyester resin (B) and a crystalline polyester resin (C).

[toner]
The toner used in the present invention contains an amorphous polyester resin (A) from the viewpoint of realizing an image forming method excellent in low temperature fixing property, hot offset resistance, and durability.
The toner includes, for example, toner particles and an external additive.

[Toner particles]
The toner particles preferably contain an amorphous polyester resin (A).
From the viewpoint of further improving low temperature fixability and hot offset resistance, the toner particles preferably have an amorphous polyester resin (B) having a softening point different from the softening point of the amorphous polyester resin (A) by 5 ° C. or more. Is further contained.
The toner particles preferably further contain a crystalline polyester resin (C) from the viewpoint of further improving the low temperature fixability.
Toner particles include waxes, charge control agents, colorants, magnetic powders, fluidity improvers, conductivity modifiers, reinforcing fillers such as fibrous substances, antioxidants, antiaging agents, cleaning properties, etc. May contain the additive of.

<Amorphous polyester resin (A)>
The amorphous polyester resin (A) is an ethylene oxide adduct of bisphenol A having an amount of 30 mol% or more and 80 mol% or less and an ethylene oxide adduct of 30 mol% or more and 80 mol% or less from the viewpoint of realizing an image forming method excellent in low temperature fixability, hot offset resistance, and durability. It is a polycondensate of an alcohol component containing 1,4-butanediol of 20 mol% or more and 70 mol% or less and a carboxylic acid component containing an aromatic dicarboxylic acid.

（式中、ｘ及びｙはエチレンオキサイドの平均付加モル数を示し、それぞれ正の数であり、ｘとｙの和の値は、１以上、好ましくは1.5以上であり、そして、16以下、好ましくは8以下、より好ましくは4以下である）で表されるビスフェノールＡのエチレンオキサイド付加物である。
ビスフェノールＡのエチレンオキサイド付加物の量は、低温定着性、耐ホットオフセット性、及び耐久性に優れる画像形成方法を実現する観点から、アルコール成分中、30モル％以上であり、好ましくは40モル％以上、より好ましくは50モル％以上であり、そして、80モル％以下であり、好ましくは70モル％以下、より好ましくは60モル％以下である。 The ethylene oxide adduct of bisphenol A is preferably of formula (I) :.

(In the formula, x and y indicate the average number of moles of ethylene oxide added, each of which is a positive number, and the value of the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 16 or less. Is an ethylene oxide adduct of bisphenol A represented by 8 or less, more preferably 4 or less).
The amount of the ethylene oxide adduct of bisphenol A is 30 mol% or more, preferably 40 mol% or more in the alcohol component from the viewpoint of realizing an image forming method excellent in low temperature fixing property, hot offset resistance, and durability. The above is more preferably 50 mol% or more, and 80 mol% or less, preferably 70 mol% or less, and more preferably 60 mol% or less.

The amount of 1,4-butanediol is 20 mol% or more, preferably 30 mol% or more in the alcohol component from the viewpoint of realizing an image forming method excellent in low temperature fixing property, hot offset resistance, and durability. , More preferably 40 mol% or more, and 70 mol% or less, preferably 60 mol% or less, more preferably 50 mol% or less.

In addition to the above, as alcohol components, aromatic diols other than the ethylene oxide adduct of bisphenol A, linear or branched aliphatic diols other than 1,4-butanediol, alicyclic diols, and polyhydric alcohols of trivalent or higher. May include.
Examples of the aromatic diol other than the ethylene oxide adduct of bisphenol A include the propylene oxide adduct of bisphenol A [2,2-bis (4-hydroxyphenyl) propane]. One or more of these may be used.
Examples of the linear or branched aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. , 2,3-Butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1 , 12-Dodecanediol.
Examples of the alicyclic diol include hydrogenated bisphenol A [2,2-bis (4-hydroxycyclohexyl) propane] and alkylene oxide having 2 or more and 4 or less carbon atoms of hydrogenated bisphenol A (average number of moles of 2 or more and 12). The following) Additives are mentioned.
Examples of the trihydric or higher polyhydric alcohol include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.
These alcohol components may be used alone or in combination of two or more.

The carboxylic acid component contains an aromatic dicarboxylic acid from the viewpoint of realizing an image forming method excellent in low temperature fixing property, hot offset resistance, and durability.
Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable.
The amount of the aromatic dicarboxylic acid is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 90 mol% in the carboxylic acid component. The above, and 100 mol% or less, preferably 98 mol% or less.

Examples of the carboxylic acid component other than the aromatic dicarboxylic acid include other dicarboxylic acids and polyvalent carboxylic acids having a trivalent or higher valence.
Examples of other dicarboxylic acids include linear or branched aliphatic dicarboxylic acids and cyclic dicarboxylic acids.
Examples of the linear or branched aliphatic dicarboxylic acid include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, and tetradecanedi. Examples thereof include acid and succinic acid substituted with an aliphatic hydrocarbon group having 1 or more and 20 or less carbon atoms. Examples of the succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.

The trivalent or higher valent carboxylic acid is preferably a trivalent carboxylic acid, and examples thereof include trimellitic acid. Among these, trimellitic acid or its anhydride is preferable.
When a trivalent or higher polyvalent carboxylic acid is contained, the amount of the trivalent or higher polyvalent carboxylic acid is preferably 1 mol% or more, more preferably 2 mol% or more, and preferably 2 mol% or more in the carboxylic acid component. It is 30 mol% or less, more preferably 20 mol% or less, still more preferably 10 mol% or less, still more preferably 5 mol% or less.
As these carboxylic acid components, one kind or two or more kinds may be used.

The ratio of the carboxy 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, and preferably 1.3 or less, more preferably 1.2 or less.

[Physical characteristics of amorphous polyester resin (A)]
The acid value of the amorphous polyester resin (A) is preferably 2 mgKOH / g or more, more preferably 3 mgKOH / g or more, still more preferably 4 mgKOH / g or more, and preferably 45 mgKOH / g or less, more preferably. It is 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, still more preferably 10 mgKOH / g or less.

The hydroxyl value of the amorphous polyester resin (A) is preferably 5 mgKOH / g or more, more preferably 15 mgKOH / g or more, still more preferably 20 mgKOH / g or more, still more preferably 25 mgKOH / g or more, and preferably 25 mgKOH / g or more. It is 60 mgKOH / g or less, more preferably 50 mgKOH / g or less.

The softening point of the amorphous polyester resin (A) is preferably 70 ° C. or higher, more preferably 90 ° C. or higher, still more preferably 100 ° C. or higher, still more preferably 100 ° C. or higher, from the viewpoint of further improving durability and hot offset resistance. It is 110 ° C or higher.
The softening point of the amorphous polyester resin (A) is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, still more preferably 140 ° C. or lower, still more preferably 130 ° C. or lower, from the viewpoint of further improving low temperature fixability. It is more preferably 120 ° C. or lower, still more preferably 110 ° C. or lower.

The glass transition temperature of the amorphous polyester resin (A) is preferably 45 ° C. or higher, more preferably 48 ° C. or higher, still more preferably 50 ° C. or higher, and preferably 50 ° C. or higher, from the viewpoint of obtaining a toner having excellent low-temperature fixability. Is 70 ° C. or lower, more preferably 65 ° C. or lower, still more preferably 60 ° C. or lower.

The acid value, hydroxyl value, softening point, and glass transition temperature of the amorphous polyester resin (A) are appropriately adjusted according to the type and amount of the raw material monomer used, and the production conditions such as reaction temperature, reaction time, and cooling rate. And their values can be determined by the method described in the examples.
When two or more types of amorphous polyester resin (A) are used in combination, the acid value, hydroxyl value, softening point, and glass transition temperature of any of the resins must be within the above ranges. Is preferable.

[Manufacturing method of amorphous polyester resin (A)]
The method for producing the amorphous polyester resin (A) includes, for example, polycondensation of an alcohol component and a carboxylic acid component.
In the polycondensation, if necessary, an esterification catalyst such as di (2-ethylhexanoic acid) tin (II), dibutyl tin oxide, and titanium diisopropyrate bistriethanol aminated is used as the total amount of the alcohol component and the carboxylic acid component. 0.01 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass; 100 parts by mass of total amount of alcohol component and carboxylic acid component of esterification auxiliary catalyst such as galvanic acid (same as 3,4,5-trihydroxybenzoic acid) 0.001 part by mass or more and 0.5 part by mass or less; and if necessary, add a radical polymerization inhibitor such as 4-tert-butylcatechol to 0.001 part by mass or more and 0.5 part by mass with respect to 100 parts by mass of the total amount of alcohol component and carboxylic acid component. It may be polycondensed using the following.
The temperature of the polycondensation is preferably 120 ° C. or higher, more preferably 160 ° C. or higher, further preferably 180 ° C. or higher, and preferably 250 ° C. or lower, more preferably 230 ° C. or lower.
The polycondensation may be carried out in an inert gas atmosphere.
From the viewpoint of further advancing the reaction with the polycondensation and, if necessary, the bireactive monomer, a part of the carboxylic acid component is subjected to polycondensation, then addition polymerization is carried out, and then the reaction temperature is raised again, and the rest is reacted. It is preferable to add it to the system.

The content of the amorphous polyester resin (A) is preferably 20% by mass or more, more preferably 30% by mass, from the viewpoint of improving low temperature fixability, hot offset resistance, and durability in the binder resin of the toner. % Or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, and 100% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less.

The amorphous polyester resin (A) is an amorphous polyester resin for heat-fixing toner, as will be described later. The heat-fixing toner is a toner used in an image forming method for fixing an unfixed toner image by applying heat. The amorphous polyester resin (A) is used, for example, for the production of heat-fixing toner.

（式中、ＯＲ¹及びＲ²Ｏはオキシアルキレン基であり、Ｒ¹及びＲ²はそれぞれ独立にエチレン基又はプロピレン基であり、ｘ及びｙはアルキレンオキサイドの平均付加モル数を示し、それぞれ正の数であり、ｘとｙの和の値は、１以上、好ましくは1.5以上であり、そして、16以下、好ましくは8以下、より好ましくは4以下である）で表されるビスフェノールＡのアルキレンオキサイド付加物である。
ビスフェノールＡのアルキレンオキサイド付加物としては、例えば、ビスフェノールＡ〔2,2-ビス(4-ヒドロキシフェニル)プロパン〕のプロピレンオキサイド付加物、ビスフェノールＡのエチレンオキサイド付加物が挙げられる。これらの１種又は２種以上を用いてもよい。これらの中でも、ビスフェノールＡのプロピレンオキサイド付加物、ビスフェノールＡのエチレンオキサイド付加物の組合せが好ましい。
ビスフェノールＡのアルキレンオキサイド付加物の量は、アルコール成分中、好ましくは70モル％以上、より好ましくは90モル％以上、更に好ましくは95モル％以上であり、そして、100モル％以下であり、更に好ましくは100モル％である。
ビスフェノールＡのプロピレンオキサイド付加物とビスフェノールＡのエチレンオキサイド付加物とのモル比率は、ホットオフセット性及び耐久性をより向上させる観点から、好ましくは50/50以上、より好ましくは60/40以上、更に好ましくは65/45以上であり、そして、低温定着性をより向上させる観点から、好ましくは95/5以下、より好ましくは90/10以下、更に好ましくは80/20以下である。 <Amorphous polyester resin (B)>
The amorphous polyester resin (B) is a polycondensate of an alcohol component and a carboxylic acid component.
However, this does not apply to the case of the amorphous polyester resin (A).
Examples of the alcohol component include aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, aromatic diols are preferable.
The aromatic diol is preferably an alkylene oxide adduct of bisphenol A.
Preferably, equation (II):

(In the formula, OR ¹ and R ² O are oxyalkylene groups, R ¹ and R ² are independently ethylene groups or propylene groups, and x and y indicate the average number of adducts of alkylene oxide, respectively, which are positive. 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 4 or less) alkylene of bisphenol A. It is an oxide adduct.
Examples of the alkylene oxide adduct of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis (4-hydroxyphenyl) propane] and an ethylene oxide adduct of bisphenol A. One or more of these may be used. Among these, a combination of a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A is preferable.
The amount of the alkylene oxide adduct of bisphenol A is preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, further, in the alcohol component. It is preferably 100 mol%.
The molar ratio of the propylene oxide adduct of bisphenol A to the ethylene oxide adduct of bisphenol A is preferably 50/50 or more, more preferably 60/40 or more, and further, from the viewpoint of further improving hot offset property and durability. It is preferably 65/45 or more, and is preferably 95/5 or less, more preferably 90/10 or less, still more preferably 80/20 or less, from the viewpoint of further improving low temperature fixability.

Examples of other alcohol components include linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Examples of linear or branched aliphatic diols, alicyclic diols, and polyhydric alcohols having a valence of 3 or more are the same as those mentioned in the above-mentioned amorphous polyester resin (A).

Examples of the carboxylic acid component include a dicarboxylic acid and a polyvalent carboxylic acid having a valence of 3 or more. Examples of the dicarboxylic acid include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, aromatic dicarboxylic acids are preferable.
As the aromatic dicarboxylic acid, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable.
The amount of aromatic dicarboxylic acid is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, and preferably 98 mol% or less, more preferably 98 mol% or more, in the carboxylic acid component. It is 95 mol% or less, more preferably 90 mol% or less.

The carboxylic acid component preferably contains a polyvalent carboxylic acid having a valence of 3 or more, and preferably contains trimellitic acid or an anhydride thereof.
The amount of the trivalent or higher polyvalent carboxylic acid is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, and preferably 40 mol% or less in the carboxylic acid component. , More preferably 30 mol% or less, still more preferably 20 mol% or less.

Examples of the aromatic dicarboxylic acid, the linear or branched aliphatic dicarboxylic acid, and the trivalent or higher-valent polyvalent carboxylic acid are the same as those mentioned in the above-mentioned amorphous polyester resin (A).

[Physical characteristics of amorphous polyester resin (B)]
The acid value of the amorphous polyester resin (B) is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, still more preferably 4 mgKOH / g or more, and preferably 40 mgKOH / g or less, more preferably 40 mgKOH / g or less. It is 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, still more preferably 10 mgKOH / g or less.

The hydroxyl value of the amorphous polyester resin (B) is preferably 5 mgKOH / g or more, more preferably 15 mgKOH / g or more, still more preferably 20 mgKOH / g or more, still more preferably 25 mgKOH / g or more, and preferably 25 mgKOH / g or more. It is 60 mgKOH / g or less, more preferably 50 mgKOH / g or less.

The softening point of the amorphous polyester resin (B) is preferably different from the softening point of the amorphous polyester resin (A) by 5 ° C. or more, more preferably 10 ° C. or more, still more preferably 20 ° C. or more, and further. It is preferably different by 30 ° C. or higher, and is preferably different from the softening point of the amorphous polyester resin (A) by 60 ° C. or lower, more preferably 50 ° C. or lower, and further preferably 40 ° C. or lower.
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, still more preferably 110 ° C. or higher, from the viewpoint of further improving low temperature fixability. be.
The softening point of the amorphous polyester resin (B) is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, still more preferably 140 ° C. or lower, still more preferably 140 ° C. or lower, from the viewpoint of further improving durability and hot offset resistance. It is 130 ° C. or lower, more preferably 120 ° C. or lower, still more preferably 110 ° C. or lower.

The glass transition temperature of the amorphous polyester resin (B) is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, further preferably 60 ° C. or higher, and preferably 80 ° C. or lower, more preferably 75 ° C. or lower. , More preferably 70 ° C. or lower.

The acid value, hydroxyl value, softening point, and glass transition temperature of the amorphous polyester resin (B) are appropriately adjusted according to the type and amount of the raw material monomer used, and the production conditions such as reaction temperature, reaction time, and cooling rate. And their values can be determined by the method described in the examples.
When two or more kinds of amorphous polyester resin (B) are used in combination, the acid value, hydroxyl value, softening point, and glass transition temperature obtained as a mixture thereof are within the above ranges. Is preferable.

The amorphous polyester resin (B) is obtained, for example, by polycondensation of an alcohol component and a carboxylic acid component. As the conditions for polycondensation, for example, the conditions shown in the above-mentioned method for producing an amorphous polyester resin (A) can be applied.

When the amorphous polyester resin (B) is contained, the mass ratio [(A) / (B)] of the amorphous polyester resin (A) and the amorphous polyester resin (B) is low temperature fixability and resistance. From the viewpoint of improving hot offset property and durability, it is preferably 20/80 or more, more preferably 30/70 or more, still more preferably 40/60 or more, still more preferably 50/50 or more, and preferably. It is 90/10 or less, more preferably 80/20 or less.

When the amorphous polyester resin (B) is contained, the content of the amorphous polyester resin (B) is from the viewpoint of improving low temperature fixability, hot offset resistance, and durability in the binder resin of the toner. It is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, still more preferably 50% by mass or less. Is.

<Crystalline polyester resin (C)>
The toner preferably contains a crystalline polyester resin (C) from the viewpoint of obtaining a toner having excellent low temperature fixability.
The crystalline polyester resin (C) is, for example, a polycondensate of an alcohol component and a carboxylic acid component.
As the alcohol component, α, ω-aliphatic diol is preferable.
The number of carbon atoms of the α, ω-aliphatic diol is preferably 2 or more, more preferably 4 or more, still more preferably 6 or more, and preferably 16 or less, more preferably 14 or less, still more preferably 12 or less. be.
Examples of the α, ω-aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptanediol. 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol Can be mentioned. Among these, ethylene glycol, 1,6-hexanediol, or 1,10-decanediol is preferable, and 1,6-hexanediol is more preferable.

The amount of α, ω-aliphatic diol is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 in the alcohol component. It is less than or equal to mol%, more preferably 100 mol%.

The alcohol component may contain other alcohol components different from the α, ω-aliphatic diol. Examples of other alcohol components include aliphatic diols other than α and ω-aliphatic diols such as 1,2-propylene glycol and neopentyl glycol; aromatic diols such as alkylene oxide adducts of bisphenol A; glycerin and penta. Examples thereof include alcohols having a valence of 3 or more such as erythritol and trimethylol propane. These alcohol components may be used alone or in combination of two or more.

Examples of the carboxylic acid component include aliphatic dicarboxylic acids.
The aliphatic dicarboxylic acid has preferably 4 or more, more preferably 8 or more, still more preferably 10 or more, and preferably 14 or less, more preferably 12 or less.
Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid, dodecanedioic acid, or tetradecanedioic acid is preferable, and sebacic acid is more preferable. As these carboxylic acid components, one kind or two or more kinds may be used.

The amount of the aliphatic dicarboxylic acid is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol in the carboxylic acid component. % Or less, more preferably 100 mol%.

The carboxylic acid component may contain another carboxylic acid component different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; and polyvalent carboxylic acids having a valence of 3 or more. As these carboxylic acid components, one kind or two or more kinds may be used.

The ratio of the carboxy 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, and preferably 1.3 or less, more preferably 1.2 or less.

[Physical characteristics of crystalline polyester resin (C)]
The softening point of the crystalline polyester resin (C) is preferably 60 ° C. or higher, more preferably 65 ° C. or higher, still more preferably 70 ° C. or higher, and further improves low temperature fixability, from the viewpoint of further improving durability. From the viewpoint of improvement, it is preferably 150 ° C. or lower, more preferably 120 ° C. or lower, and further preferably 100 ° C. or lower.

The melting point of the crystalline polyester resin (C) is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 65 ° C. or higher, and further improves low temperature fixability, from the viewpoint of further improving durability. From the viewpoint of keeping the temperature, it is preferably 100 ° C. or lower, more preferably 90 ° C. or lower.

The acid value of the crystalline polyester resin (C) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and preferably 35 mgKOH / g or less from the viewpoint of further improving durability and low temperature fixability. , More preferably 25 mgKOH / g or less, still more preferably 20 mgKOH / g or less.

The hydroxyl value of the crystalline polyester resin (C) is preferably 1 mgKOH / g or more, more preferably 2 mgKOH / g or more, still more preferably 3 mgKOH / g or more, from the viewpoint of further improving durability and low temperature fixability. The amount is preferably 35 mgKOH / g or less, more preferably 30 mgKOH / g or less, and further preferably 20 mgKOH / g or less.

The softening point, melting point, acid value, and hydroxyl value of the crystalline polyester resin (C) can be appropriately adjusted depending on the type and ratio of the raw material monomers, and the production conditions such as reaction temperature, reaction time, and cooling rate. Those values are obtained by the method described in Examples described later. When two or more kinds of crystalline polyester resin (C) are used in combination, it is preferable that the softening point, melting point, acid value, and hydroxyl value obtained as a mixture thereof are within the above ranges. ..

The crystalline polyester resin (C) is obtained, for example, by polycondensation of an alcohol component and a carboxylic acid component. As the conditions for polycondensation, for example, the conditions shown for polycondensation in the above-mentioned amorphous polyester resin (A) can be applied.

The mass ratio [(A) / (C)] of the amorphous polyester resin (A) and the crystalline polyester resin (C) is preferably 1/99 or more, preferably 80, from the viewpoint of further improving the low temperature fixability. It is /20 or more, more preferably 85/15 or more, and from the viewpoint of further improving durability, it is preferably 98/2 or less, more preferably 95/5 or less, still more preferably 90/10 or less.

The mass ratio [(C) / ((A) + (B))] of the crystalline polyester resin (C) to the total of the amorphous polyester resin (A) and the amorphous polyester resin (B) is durable. From the viewpoint of further improving the property, it is preferably 1/99 or more, more preferably 2/98 or more, still more preferably 5/95 or more, still more preferably 8/92 or more, and further improve the low temperature fixability. From the viewpoint, it is preferably 50/50 or less, more preferably 40/60 or less, still more preferably 30/70 or less, still more preferably 20/80 or less, still more preferably 15/85 or less.

The content of the amorphous polyester resin (A), the amorphous polyester resin (B) and the crystalline polyester resin (C) in the binder resin of the toner is preferably 80% by mass or more, more preferably 90% by mass. The above is more preferably 95% by mass or more, 100% by mass or less, and preferably 100% by mass.

<Wax>
Examples of the wax include hydrocarbon wax, ester wax, silicone wax, and fatty acid amide wax.
Examples of the hydrocarbon wax include minerals such as paraffin wax and Fishertropush wax or petroleum-based hydrocarbon wax; synthetic hydrocarbon wax such as polyolefin wax such as polyethylene wax, polypropylene wax and polybutene wax.
Examples of the ester wax include minerals such as Montan wax or petroleum-based ester waxes; plant-based ester waxes such as carnauba wax, rice wax and candelilla wax; and animal-based ester waxes such as honey wax.
Examples of the fatty acid amide wax include oleic acid amide and stearic acid amide. These may be used alone or in combination of two or more.
Among these, hydrocarbon wax or ester wax is preferable, and hydrocarbon wax is more preferable.

The melting point of the wax is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, and preferably 160 ° C. or lower, more preferably 150 ° C. or lower, still more preferably 140 ° C. or lower.
When two or more kinds of waxes are used in combination, it is preferable that the melting point of each wax is within the above range.
The wax content is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, still more preferably 2 parts by mass or more, and preferably 20 parts by mass or less, based on 100 parts by mass of the binder resin. It is more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less.

<Charge control agent>
The charge control agent may contain either a positive charge control agent or a negative charge control agent.
Positive charge control agents include niglosin dyes such as "niglocin base EX", "oil black BS", "oil black SO", "bontron N-01", "bontron N-04", and "bontron N-07". , "Bontron N-09", "Bontron N-11" (all manufactured by Orient Chemical Industry Co., Ltd.), etc .; Triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds, for example, " Bontron P-51 "(manufactured by Orient Chemical Industry Co., Ltd.), cetyltrimethylammonium bromide," COPY CHARGE PX VP435 "(manufactured by Clariant), etc .; Polyamine resin, for example," AFP-B "(manufactured by Orient Chemical Industry Co., Ltd.), etc. Imidazole derivatives such as "PLZ-2001" and "PLZ-8001" (manufactured by Shikoku Kasei Kogyo Co., Ltd.); styrene-acrylic resins such as "FCA-701PT" (manufactured by Fujikura Kasei Co., Ltd.). Be done.

Negative charge control agents include metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" ( (Manufactured by Orient Chemical Industry Co., Ltd.), "Eisenspiron Black TRH", "T-77" (manufactured by Hodoya Chemical Industry Co., Ltd.), etc .; Metal compounds of benzylic acid compounds, for example, "LR-147", " LR-297 "(above, manufactured by Nippon Carlit Co., Ltd.), etc .; Metal compounds of salicylic acid compounds, for example," Bontron E-81 "," Bontron E-84 "," Bontron E-88 "," Bontron E-304 " (The above is manufactured by Orient Chemical Industry Co., Ltd.), "TN-105" (manufactured by Hodoya Chemical Industry Co., Ltd.), etc .; Copper phthalocyanine dye; Quadruple ammonium salt, for example, "COPY CHARGE NX VP434" (manufactured by Clariant), Nitro Imidazole derivatives and the like; examples include organic metal compounds and the like.
Among the charge control agents, a negative charge control agent is preferable, and a metal compound of a benzylic acid compound is more preferable.

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 with respect to 100 parts by mass of the binder resin. Hereinafter, it is more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less.

<Colorant>
As the colorant, all of the dyes and pigments used as colorants for toner can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, and Rhodamine-B base. Solvent Red 49, Solvent Red 146, Solvent Blue 35, Kinacridone, Carmine 6B, Disazoero and the like can be used, and the toner of the present invention may be any of black toner and other color toners.

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 with respect to 100 parts by mass of the binder resin from the viewpoint of improving the image density of the toner. Parts or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less.

[Toner manufacturing method]
The toner may be a toner obtained by any known method such as a melt-kneading method, an emulsification phase inversion method, a polymerization method, an emulsification aggregation method, etc., but from the viewpoint of productivity and dispersibility of the colorant, the toner is melted. Grinded toner by the kneading method is preferable.
In the case of crushed toner by the melt-kneading method, for example, raw materials such as amorphous polyester resin (A), amorphous polyester resin (B), crystalline polyester resin (C), wax, charge control agent, and colorant are used as Henshell. After uniformly mixing with a mixer such as a mixer, the resin can be melt-kneaded with a closed kneader, a single-screw or twin-screw extruder, an open roll type kneader, or the like, cooled, pulverized, and classified.
The method for producing the toner preferably includes a step of melt-kneading the mixture containing the above-mentioned binder resin composition at a temperature within the range of 80 ° C. or higher and 160 ° C. or lower. The melt-kneading temperature is preferably 90 ° C. or higher, more preferably 100 ° C. or higher, and preferably 160 ° C. or lower, more preferably 150 ° C. or lower.
The method for producing a toner preferably comprises a step of pulverizing and classifying the mixture obtained by melt-kneading to obtain toner particles. The pulverization and classification can be performed by a known method.

The volume median particle size (D ₅₀ ) of the toner particles is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, from the viewpoint of obtaining a high-quality image. It is preferably 8 μm or less, more preferably 6 μm or less.

The toner is preferably treated by adding a fluidizing agent or the like as an external additive to the surface of the toner particles.
Examples of the external additive include hydrophobic silica fine particles, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic material fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Of these, hydrophobic silica is preferred.
When an external additive is used, the amount of the external additive added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 5 parts by mass or less with respect to 100 parts by mass of the toner particles. It is more preferably 4.5 parts by mass or less, still more preferably 4 parts by mass or less.

The toner is used for developing a latent image formed by an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like. The toner can be used as a one-component developer or mixed with a carrier as a two-component developer.

[Image formation method]
Hereinafter, the image forming method according to the present invention will be described with reference to specific examples, but the image forming method according to the present invention is not limited to the method.
The image forming method according to the present invention can be performed using, for example, an image forming apparatus. FIG. 1 is a schematic configuration diagram of an image forming apparatus.
The image forming apparatus 1 includes, for example, a photosensitive drum 12, a charging unit 13, an exposure unit 14, a developing unit 15, a transfer roller 16, and a heat fixing unit 17.

The photosensitive drum 12 has a cylindrical shape that can rotate about the central axis.
The charging unit 13 is configured to charge the surface of the photosensitive drum 12. The charging unit 13 is, for example, a charging roller. The charging unit 13 may be a scorotron type charging device.
The exposure unit 14 is configured to expose the surface of the photosensitive drum 12 charged by the charging unit 13. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 12. The exposure unit 14 is, for example, a laser scan unit or an LED array.

The developing unit 15 is configured to supply toner to the surface of the photosensitive drum 12. As a result, the electrostatic latent image is developed, and an unfixed toner image is formed on the surface of the photosensitive drum 12. The developing unit 15 has a toner accommodating unit 151 and a developing roller 152. The toner accommodating unit 151 accommodates toner. The developing roller 152 is configured to supply the toner in the toner accommodating portion 151 to the surface of the photosensitive drum 12.

The transfer roller 16 is configured to transfer the unfixed toner image formed on the surface of the photosensitive drum 12 from the photosensitive drum 12 to the printing medium S. As a result, an unfixed toner image is formed on the print medium S. The transfer roller 16 comes into contact with the photosensitive drum 12 via the print medium S. The print medium S is, for example, paper.

The heat fixing unit 17 is configured to apply heat to the unfixed toner image on the print medium S to fix it. The heat fixing unit is, for example, a heat fixing roller.
The heat fixing temperature is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, further preferably 120 ° C. or higher, and preferably 180 ° C. or lower, more preferably 170 ° C. or lower, still more preferably 160 ° C. or lower. be.
As described above, by applying heat to fix the unfixed toner image formed by the toner according to the present invention, it is possible to realize an image forming method excellent in low temperature fixing property, hot offset resistance, and durability.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The physical properties of the resin and the like were measured by the following methods.

[measurement]
[Acid value and hydroxyl value of resin]
Measure based on the method of JIS K 0070: 1992. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K 0070: 1992 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Resin softening point, maximum endothermic temperature, glass transition temperature]
(1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), a 1 g sample is heated at a heating rate of 6 ° C / min, and a load of 1.96 MPa is applied by a plunger to a diameter of 1 mm. , Extrude from a 1 mm long nozzle. 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 used as the softening point.
(2) Temperature of the highest peak of heat absorption Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), cool from room temperature (20 ° C) to 0 ° C at a temperature lowering rate of 10 ° C / min. Hold the sample as it is for 1 minute, and then measure while raising the temperature to 180 ° C at a heating rate of 10 ° C / min. Of the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the maximum endothermic temperature.
(3) Glass transition temperature Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample in an aluminum pan, raise the temperature to 200 ° C, and then use the temperature. Cool from temperature to 0 ° C at a temperature drop 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 of the baseline below the maximum endothermic temperature and the tangent line indicating the maximum slope from the rising portion of the peak to the peak of the peak is defined as the glass transition temperature.

[Melting point of resin or wax]
Using the differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and then lower the temperature from 200 ° C to 10 ° C / min. Cool to 0 ° C. Next, the sample is heated at a heating rate of 10 ° C./min, the amount of heat is measured, and the maximum peak temperature of endotherm is taken as the melting point.

[Volume medium particle size of toner particles (D ₅₀ )]
The volume median particle size (D ₅₀ ) of the toner particles is measured as follows.
-Measuring machine: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter Co., Ltd.)
・ Aperture diameter: 50 μm
-Analysis software: "Multisizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter Co., Ltd.)
-Electrolytic solution: "Isoton (registered trademark) II" (manufactured by Beckman Coulter Co., Ltd.)
-Dispersion: Polyoxyethylene lauryl ether "Emargen (registered trademark) 109P" [HLB (Hydrophile-Lipophile Balance) = 13.6, manufactured by Kao Corporation) was dissolved in the electrolyte to obtain a dispersion with a concentration of 5% by mass. rice field.
-Dispersion conditions: Add 10 mg of the measured sample of toner particles after drying to 5 mL of the above dispersion, disperse for 1 minute with an ultrasonic disperser, then add 25 mL of electrolyte, and further add to the ultrasonic disperser. The mixture was dispersed for 1 minute to prepare a sample dispersion.
-Measurement conditions: By adding the sample dispersion to 100 mL of the electrolytic solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size is measured. The volume median particle size (D ₅₀ ) was determined from the distribution.

[Manufacturing of resin]
Production Examples A1-A5, A81-A83 (Amorphous polyester resin A-1-A-5, A-81-A-83)
Place the raw material monomers and esterification catalysts other than the trimellitic acid anhydride shown in Table 1 in a 10-liter four-necked flask equipped with a thermometer, stainless stir bar, flow-down condenser and nitrogen introduction tube to create a nitrogen atmosphere. The temperature was raised from 180 ° C to 230 ° C over 10 hours in a mantle heater. After that, trimellitic acid anhydride was added, and the reaction was carried out at 220 ° C. at 8.0 kPa until the softening point shown in the table was reached, and the amorphous polyester resins A-1 to A-5 and A-81 to A- Obtained 83.

Production Examples B1, B2 (Resin B-1, B-2)
Place the raw polyester monomers other than the trimellitic acid anhydride shown in Table 2 in a 10 L four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser equipped with a dehydration tube, and a nitrogen introduction tube, and place them in a nitrogen atmosphere. In a mantle heater, the mixture was hydrocondensed at 230 ° C. for 7 hours. After adding trimellitic acid anhydride at 200 ° C, the temperature is raised to 210 ° C, a polycondensation reaction is carried out, and the reaction is carried out until the softening point reaches the softening point shown in the table, and the resins B-1 to B-2 are reacted. Got

Production Example C1 (Crystalline Polyester Resin C-1)
The polyester monomers shown in Table 3 are placed in a 10 L four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser equipped with a dehydration tube, and a nitrogen inlet tube, and placed in a mantle heater in a nitrogen atmosphere for 200. The temperature was raised to ° C over 8 hours. Then, an esterification catalyst was added, and the reaction was carried out at 8.0 kPa until the softening point shown in Table 3 was reached to obtain a crystalline polyester resin C-1.

[Manufacturing of toner]
Examples 1 to 6 and Comparative Examples 1 to 3 (toners 1 to 6,81 to 83)
At the ratio shown in Table 4, 100 parts by mass of the binder resin, 5 parts by mass of the colorant "ECB-301" (manufactured by Dainichiseika Kogyo Co., Ltd.), and the charge control agent "LR-147" (manufactured by Nippon Carlit Co., Ltd.) 1 Mass part, mold release agent "Carnauba Wax C1" (manufactured by Hiroyuki Kato Co., Ltd., melting point: 80 ° C) After stirring well with a Henshell mixer, the total length of the kneaded part is 1560 mm, the screw diameter is 42 mm, and the barrel inner diameter is 43 mm. The mixture was melt-kneaded using the same-direction rotary twin-screw extruder. The rotation speed of the roll was 200 r / min, the set heating temperature in the roll was 90 ° C, the temperature of the kneaded product was 140 ° C, the supply speed of the kneaded product was 10 kg / hour, and the average residence time was about 18 seconds. The obtained kneaded product is cooled from 140 ° C. to 50 ° C. for 1.5 hours, rolled and cooled at 50 ° C. with a cooling roller, allowed to stand at 45 ° C. for 4 hours, and then subjected to a medium volume particle size ( _D50 ) by a jet mill. ) 5.5 μm toner particles were obtained.

For 100 parts by mass of the obtained toner particles, 1.5 parts by mass of the external additive "Aerosil R-972" (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd., number average particle diameter: 16 nm) and "SI-Y" (hydrophobicity) Silica, manufactured by Nippon Aerosil Co., Ltd., number average particle size: 40 nm) 1.0 part by mass is added and mixed with a Henshell mixer at 3600 r / min for 5 minutes to perform an external additive treatment, and toner 1 to 6,81 to Obtained 83.

[evaluation]
[Low temperature fixing property and high temperature offset resistance]
Toner was mounted on a device that was improved so that the fixing machine of the copying machine "AR-505" (manufactured by Sharp Corporation) could be fixed outside the device, and printed matter was obtained in an unfixed state (printed area: 2 cm). × 12 cm, adhesion amount: 0.5 mg / cm ² ). After that, using a fixing machine (fixing speed 300 mm / sec) adjusted so that the total fixing pressure becomes 40 kgf, the temperature of the fixing roll is gradually increased from 100 ° C to 240 ° C by 5 ° C, and unfixed at each temperature. A fixing test was performed on the printed matter in the state. Attach the cellophane adhesive tape "UNICEF Cellophane" (manufactured by Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z 1522) to the image part of the obtained printed matter, pass it through a fixing roller set at 30 ° C, and then peel off the tape. rice field. The paper used for printing was "CopyBond SF-70NA" (manufactured by Sharp Corporation, 75 g / m ² ).
The optical reflection density before and after the tape was applied was measured using a reflection densitometer "RD-915" (manufactured by Gretag Macbeth), and the ratio of the two (after peeling / before applying x 100) was initially 90%. The temperature of the fixing roller exceeding the above was set as the low fixing temperature. The results are shown in Table 4. The lower the low fixing temperature, the better the low temperature fixing property. The minimum fixing temperature is preferably 140 ° C. or lower, more preferably 130 ° C. or lower.
Further, the fixing image obtained above was visually judged, and the lowest temperature of the fixing roll in which the high temperature offset was observed was defined as the high temperature offset temperature. The results are shown in Table 4. The higher the high temperature offset temperature, the better the high temperature offset resistance. The high temperature offset temperature is preferably 160 ° C. or higher, more preferably 170 ° C. or higher.

〔durability〕
Toner is mounted on the laser printer "Page Presto N-4" (manufactured by Casio Computer Co., Ltd., fixing: contact fixing method, development: non-magnetic one-component development method, development roll diameter: 2.3 cm), temperature 40 ° C, relative humidity. Printing was performed with a diagonal stripe pattern with a blackening rate of 5.5% under the condition of 85%. On the way, a solid black image was printed every 500 sheets, and streaks on the image were confirmed. Durability was evaluated according to the following evaluation criteria, with the number of printed sheets up to the time when streaks were visually observed on the image as the number of sheets in which streaks were generated due to the fusion and adhesion of toner to the developing roll. The results are shown in Table 4. The greater the number of streaks, the better the durability of the toner. The number of sheets is preferably 4,000 or more, and more preferably 5,000 or more.

As described above, from Examples and Comparative Examples, it can be seen that according to the present invention, it is possible to provide an image forming method excellent in low temperature fixing property, hot offset resistance, and durability, and a resin used in the method.

1: Image forming device 12: Photosensitive drum 13: Charging part 14: Exposure part 15: Developing part 151: Toner accommodating part 152: Developing roller 16: Transfer roller 17: Heat fixing part S: Printing medium

Claims (8)

Alcohol component containing an ethylene oxide adduct of bisphenol A of 30 mol% or more and 60 mol% or less and 1,4-butanediol of 40 mol% or more and 70 mol% or less (however, it has an ester group and a carboxy group in the molecule. A method for producing a toner containing an amorphous polyester resin (A ) , which is a polycondensate of a carboxylic acid component containing an aromatic dicarboxylic acid.
The toner is a pulverized toner produced by a melt-kneading method.
A method for producing a toner, which comprises a step of melt-kneading the mixture containing the amorphous polyester resin (A) at a temperature within the range of 80 ° C. or higher and 160 ° C. or lower . The method for producing a toner according to claim 1, wherein the amorphous polyester resin (A) has a glass transition temperature of 45 ° C. or higher and 70 ° C. or lower, and an acid value of 2 mgKOH / g or higher and 45 mgKOH / g or lower. The toner according to claim 1 or 2, wherein the toner and the mixture further contain an amorphous polyester resin (B) having a softening point different from the softening point of the amorphous polyester resin (A) by 5 ° C. or more. Manufacturing method . The method for producing a toner according to any one of claims 1 to 3, wherein the toner and the mixture further contain a crystalline polyester resin (C). In the toner and the mixture , the mass ratio of the amorphous polyester resin (A) to the crystalline polyester resin (C) [acrystalline polyester resin (A) / crystalline polyester resin (C)] is 80/20 or more. The method for producing a toner according to claim 4, which is 98/2 or less. Alcohol component containing an ethylene oxide adduct of bisphenol A of 30 mol% or more and 60 mol% or less and 1,4-butanediol of 40 mol% or more and 70 mol% or less (however, it has an ester group and a carboxy group in the molecule. A toner containing an amorphous polyester resin (A ) which is a polycondensate of a carboxylic acid component containing an aromatic dicarboxylic acid and the toner is a pulverized toner obtained by a melt-kneading method . The toner according to claim 6, wherein the amorphous polyester resin has a softening point of 70 ° C. or higher and 160 ° C. or lower. Alcohol component containing an ethylene oxide adduct of bisphenol A of 30 mol% or more and 60 mol% or less and 1,4-butanediol of 40 mol% or more and 70 mol% or less (however, it has an ester group and a carboxy group in the molecule. A step of forming an unfixed toner image on a print medium with a toner containing an amorphous polyester resin (A) which is a polycondensate of a carboxylic acid component containing an aromatic dicarboxylic acid.
The fixing process of applying heat to the unfixed toner image to fix it,
It is an image forming method having
An image forming method in which the toner is pulverized toner by a melt-kneading method.

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