JP6365042B2 - Polyester resin for toner, toner for developing electrostatic image, developer for electrostatic image, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

  The present invention relates to a polyester resin for toner, an electrostatic charge image developing toner, an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method.

  As a polyester for toner, a polyester obtained by polycondensation of rosin diol, which is a reaction product of rosin and an epoxy compound, and dicarboxylic acid is disclosed (for example, see Patent Documents 1 to 3).

Japanese Patent No. 4699559 Japanese Patent No. 5267701 Japanese Patent No. 5267702

  An object of this invention is to provide the polyester resin for toners which is excellent in low temperature fixability.

The above problem is solved by the following means. That is,
The invention according to claim 1
Phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipine At least one selected from the group consisting of acids, sebacic acid, azelaic acid, dimer acid, alkyl succinic acid having an alkyl group having 1 to 20 carbon atoms, and alkenyl succinic acid having an alkenyl group having 2 to 20 carbon atoms A dicarboxylic acid-derived repeating unit and a dialcohol-derived repeating unit represented by the following general formula (1):
A polyester resin for toner, wherein the content of the repeating unit derived from dialcohol represented by the following general formula (1) is 20% by mass or more and 50% by mass or less.

In general formula (1), R ¹ and R ² each independently represent hydrogen or a methyl group. L ¹ represents a divalent linking group selected from the group consisting of an ether group, a chain alkylene group, a cyclic alkylene group, and combinations thereof, and L ² and L ³ are each independently a carbonyl group, an ester group, Represents a divalent linking group selected from the group consisting of an ether group, a sulfonyl group, a chain alkylene group, a cyclic alkylene group, an arylene group, and combinations thereof, and the ring is represented by L ¹ and L ² or L ¹ and L ^3. It may be formed. A ¹ and A ² each independently represents a rosin ester group derived from hydrogenated rosin.

The invention according to claim 2
The polyester resin for toner according to claim 1, which satisfies the following condition (1) and condition (2).
Condition (1): Tetrahydroabietic acid-derived rosin ester groups occupy 20% or more of all rosin ester groups.
Condition (2): The total of rosin ester groups derived from tetrahydroabietic acid and rosin ester groups derived from dihydroabietic acid accounts for 60% or more of the total rosin ester groups.

The invention according to claim 3
The polyester resin for toner according to claim 1, wherein the glass transition temperature is 65 ° C. or less.

The invention according to claim 4
A toner for developing an electrostatic charge image, comprising toner particles containing the polyester resin for toner according to any one of claims 1 to 3.

The invention according to claim 5
An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 4.

The invention according to claim 6
Containing the electrostatic image developing toner according to claim 4;
A toner cartridge to be attached to and detached from the image forming apparatus.

The invention according to claim 7 provides:
A developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus.

The invention according to claim 8 provides:
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising:

The invention according to claim 9 is:
A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 5;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising:

According to the first aspect of the present invention, there is provided a polyester resin for a toner excellent in low-temperature fixability as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) is out of the above range. Provided.
According to the second aspect of the present invention, there is provided a polyester resin for toner that is superior in low-temperature fixability as compared with a case where at least one of the conditions (1) and (2) is not satisfied.
According to the third aspect of the present invention, there is provided a polyester resin for toner which is superior in low-temperature fixability as compared with a case where the glass transition temperature is outside the above range.

According to the invention of claim 4, the electrostatic charge is excellent in low-temperature fixability as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) in the polyester is outside the above range. An image developing toner is provided.
According to the invention of claim 5, the low temperature fixability of the toner is excellent as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) in the polyester is outside the above range. An electrostatic charge image developer is provided.

According to the invention of claim 6, the low temperature fixability of the toner is excellent as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) in the polyester is outside the above range. A toner cartridge is provided.
According to the seventh aspect of the invention, the low temperature fixability of the toner is excellent as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) in the polyester is out of the above range. A process cartridge is provided.
According to the eighth aspect of the invention, the low temperature fixability of the toner is excellent as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) in the polyester is out of the above range. An image forming apparatus is provided.
According to the ninth aspect of the invention, the low-temperature fixability of the toner is excellent as compared with the case where the content of the repeating unit derived from the dialcohol represented by the general formula (1) in the polyester is outside the above range. An image forming method is provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

  Embodiments of the present invention will be described below. These descriptions and examples are illustrative of the invention and are not intended to limit the scope of the invention.

<Polyester resin for toner>
The polyester resin for toner according to the exemplary embodiment includes a repeating unit derived from a dicarboxylic acid and a repeating unit derived from a dialcohol represented by the following general formula (1), and is represented by the following general formula (1). The content of the repeating unit derived from dialcohol is 20% by mass or more and 50% by mass or less.

In general formula (1), R ¹ and R ² each independently represent hydrogen or a methyl group. L ¹ represents a divalent linking group selected from the group consisting of an ether group, a chain alkylene group, a cyclic alkylene group, and combinations thereof, and L ² and L ³ are each independently a carbonyl group, an ester group, Represents a divalent linking group selected from the group consisting of an ether group, a sulfonyl group, a chain alkylene group, a cyclic alkylene group, an arylene group, and combinations thereof, and the ring is represented by L ¹ and L ² or L ¹ and L ^3. It may be formed. A ¹ and A ² each independently represents a rosin ester group derived from hydrogenated rosin.

  In this specification, the hydrogenated rosin is a rosin obtained by subjecting rosin to a hydrogenation reaction to eliminate unstable conjugated double bonds in the molecule, and includes tetrahydroabietic acid and dihydroabietic acid as main components.

In this specification, the rosin ester group refers to a residue obtained by removing a hydrogen atom from a carboxyl group contained in rosin, and the rosin ester group derived from a hydrogenated rosin refers to a hydrogen atom derived from a carboxyl group contained in a hydrogenated rosin. Refers to the residue removed. Hereinafter, a rosin ester group derived from a hydrogenated rosin may be referred to as a “hydrogenated rosin ester group”.
In the present specification, a rosin ester group derived from a disproportionated rosin and a rosin ester group derived from a purified rosin may be referred to as “disproportionated rosin ester group” or “purified rosin ester group”, respectively.

  In the present specification, rosin diol refers to a dihydric alcohol having at least one rosin ester group.

  Hereinafter, the dialcohol represented by the general formula (1) may be referred to as “specific rosin diol”. The polyester resin for toner according to the exemplary embodiment may be referred to as “specific polyester”.

  Conventionally, a polyester having a rosin ester group in a side chain (hereinafter referred to as “rosin ester group-containing polyester”) is known. A toner containing a rosin ester group-containing polyester is excellent in chargeability due to the high hydrophobicity of the rosin ester group and the difficulty in containing water. Further, the rigidity of the ring structure of the rosin ester group increases the toner hardness, prevents the external additive from being buried, and provides excellent cleaning properties. However, since the rosin ester group tends to increase the softening temperature of the polyester due to the rigidity exhibited by the ring structure, the toner containing the rosin ester group-containing polyester tends to increase the fixing temperature. Fixability (low temperature fixability) may be inferior when the temperature is set to ℃ or lower.

Therefore, the present embodiment provides the specific polyester as the polyester for toner. The specific polyester of this embodiment contains 20% by mass or more and 50% by mass or less of a repeating unit derived from a specific rosin diol, and therefore contains a hydrogenated rosin ester group in an amount corresponding to the content of the repeating unit.
Hydrogenated rosin ester groups are less rigid and less affected by increasing the softening temperature of polyester compared to purified rosin ester groups and disproportionated rosin ester groups. Therefore, the toner containing the specific polyester of the present embodiment contains 20% by mass or more of the repeating unit derived from the specific rosin diol, thereby ensuring the chargeability and cleaning property of the toner due to the rosin ester group. Also, the fixability (low temperature fixability) when the fixing temperature is set to 160 ° C. or less is good. On the other hand, even if it is a hydrogenated rosin ester group, if the content is too large, the fixing temperature of the toner is raised, so the content of the repeating unit derived from the specific rosin diol is 50% by mass or less.

  The specific polyester of the present embodiment is more desirably lower limit of the content of the repeating unit derived from the specific rosin diol is 22% by mass or more from the viewpoint of being excellent in chargeability, cleaning properties, and low-temperature fixability of the toner. More desirably, the content is 23% by mass or more. Further, from the viewpoint of excellent low temperature fixability, the upper limit of the content of the repeating unit derived from the specific rosin diol is more preferably 48% by mass or less, and further preferably 45% by mass or less.

  The specific polyester of this embodiment may include rosin diol other than the specific rosin diol as a dialcohol component. The total content of the repeating units derived from all rosin diols in the specific polyester is preferably 20% by mass or more and 60% by mass or less, and preferably 20% by mass or more and 50% by mass or less, from the viewpoint of achieving both toner charging properties, cleaning properties, and low-temperature fixability. More preferably, it is more preferably 25% by mass or more and 45% by mass or less.

  In the specific polyester of the present embodiment, the ratio of the specific rosin diol to the total content of rosin diol is desirably 50 mol% or more from the viewpoint of the compatibility of toner charging property, cleaning property, and low-temperature fixing property, and 60 mol. % Or more is more desirable, 70 mol% or more is more desirable, 80 mol% or more is further desirable, and 90 mol% or more is further desirable.

The specific polyester of the exemplary embodiment desirably satisfies the following condition (1) and condition (2) from the viewpoint of low-temperature fixability of the toner. In the following conditions (1) and (2), the percentage is based on the number.
Condition (1): Tetrahydroabietic acid-derived rosin ester groups occupy 20% or more of all rosin ester groups.
Condition (2): The total of rosin ester groups derived from tetrahydroabietic acid and rosin ester groups derived from dihydroabietic acid accounts for 60% or more of the total rosin ester groups.
Condition (1) is desirably 25% or more. Condition (2) is desirably 70% or more, more desirably 80% or more.
The rosin ester group derived from dihydroabietic acid preferably accounts for 20% or more of the total rosin ester group, more preferably 30% or more, still more preferably 40% or more, and 50% or more. Is more desirable.

  Hereinafter, the structural unit of the specific polyester of this embodiment, etc. are demonstrated in detail.

In the general formula (1), R ¹ and R ² each independently represent hydrogen or a methyl group. R ¹ and R ² may be the same or different, but are preferably the same.

In the general formula (1), L ¹ represents a divalent linking group selected from the group consisting of an ether group, a chain alkylene group, a cyclic alkylene group, and combinations thereof. The chain alkylene group and the cyclic alkylene group may have a substituent other than the aromatic group.
When L ¹ is the above linking group, it is easy to adjust the SP value (solubility parameter) of the polyester within an appropriate range, and the compatibility between the release agent (for example, various waxes) added to the toner and the polyester is high. Controlled to an appropriate range. If the SP value is too high, the polyester may not adhere well to the paper, and if the SP value is too low, it may easily be compatible with the wax and lose its releasability. The SP value of the polyester is desirably 8.5 to 10.0, and more desirably 8.5 to 9.5. In the present specification, the SP value of polyester is a value calculated by the Fedor method, in which the unit is (cal / cm ³ ) ^1/2 .

In the general formula (1), L ² and L ³ are each independently selected from the group consisting of a carbonyl group, an ester group, an ether group, a sulfonyl group, a chain alkylene group, a cyclic alkylene group, an arylene group, and combinations thereof. Represents a selected divalent linking group. The chain alkylene group, cyclic alkylene group, and arylene group may have a substituent. L ² and L ³ may be the same or different, but are preferably the same. A ring may be formed by L ¹ and L ² or L ¹ and L ³ .

Examples of the chain alkylene group represented by L ¹ , L ² and L ³ include linear or branched alkylene groups having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms).

Examples of the cyclic alkylene group represented by L ¹ , L ² and L ³ include a cyclic alkylene group having 3 to 7 carbon atoms (preferably 3 to 6 carbon atoms).

Examples of the arylene group represented by L ² and L ³ include a phenylene group, a naphthylene group, and an anthracene group.

  Examples of the substituent for the chain alkylene group, the cyclic alkylene group, and the arylene group include an alkyl group having 1 to 8 carbon atoms, an aryl group, and the like, and a linear, branched, or cyclic alkyl group is preferable. Specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, phenyl group and the like.

L ¹ is preferably —C—O—L ⁴ —O—C—. Here, L ⁴ represents a divalent linking group composed of an ether group, a chain alkylene group, a cyclic alkylene group, and a combination thereof. Examples of the chain alkylene group represented by L ⁴ include a linear or branched alkylene group having 1 to 8 carbon atoms (preferably 1 to 6 carbon atoms). Examples of the cyclic alkylene group represented by L ⁴ include a cyclic alkylene group having 3 to 6 carbon atoms.

L ² and L ³ are linear or branched chain alkylene groups having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), and cyclic alkylene groups having 3 to 7 carbon atoms (preferably 3 to 6 carbon atoms). A divalent linking group selected from the group consisting of a group and a combination thereof is desirable, and a linear or branched chain alkylene group having 1 to 4 carbon atoms is more desirable.

In the general formula (1), A ¹ and A ² each independently represent a rosin ester group derived from a hydrogenated rosin. That is, the specific rosin diol is a dialcohol containing two hydrogenated rosin ester groups in one molecule. A ¹ and A ² are each independently preferably a rosin ester group derived from tetrahydroabietic acid or a rosin ester group derived from dihydroabietic acid. A ¹ and A ² may be the same or different, but are preferably the same.

  Below, an example of the synthetic scheme of the specific polyester of this embodiment is shown. In the following synthesis scheme, a bifunctional epoxy compound and rosin are reacted to synthesize rosin diol, and rosin diol and dicarboxylic acid are subjected to dehydration polycondensation to synthesize polyester. Of the structural formula representing polyester, a portion surrounded by a dotted line corresponds to a rosin ester group.

  Polyester obtained by dehydration polycondensation of rosin diol and dicarboxylic acid is decomposed into monomers when hydrolyzed as shown in the following scheme example. The component of polyester can be estimated from the decomposition product.

  The specific rosin diol in the present embodiment can be synthesized by a known method, for example, by a reaction between a bifunctional epoxy compound and a hydrogenated rosin. Examples of the bifunctional epoxy compound include diglycidyl ether of aliphatic diol, diglycidyl ether of alicyclic diol, and alicyclic epoxide.

  Representative examples of diglycidyl ethers of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol as the aliphatic diol component, Examples include 1,6-hexanediol, neopentyl glycol, 1,9-nonanediol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

  Representative examples of diglycidyl ethers of alicyclic diols include hydrogenated bisphenol A as the alicyclic diol component, hydrogenated bisphenol A derivatives such as polyalkylene oxide adducts of hydrogenated bisphenol A, cyclohexanedimethanol, and the like. Can be mentioned.

  A representative example of the alicyclic epoxide is limonene dioxide.

  In this embodiment, the reaction between rosin and the bifunctional epoxy compound proceeds mainly by a ring-opening reaction between the carboxyl group of rosin and the epoxy group of the bifunctional epoxy compound. In this case, the reaction temperature is preferably higher than the melting temperature of the two components or a temperature at which uniform mixing is possible, and specifically, a range of 60 ° C. or higher and 200 ° C. or lower is common. In the reaction, a catalyst for promoting the ring-opening reaction of the epoxy group may be added.

  Examples of the catalyst include amines such as ethylenediamine, trimethylamine and 2-methylimidazole, quaternary ammonium salts such as triethylammonium bromide, triethylammonium chloride and butyltrimethylammonium chloride, and triphenylphosphine.

  For example, in a batch-type reaction, rosin and a bifunctional epoxy compound are charged into a flask equipped with a condenser, a stirrer, an inert gas inlet, a thermometer, and the like, and the reaction proceeds by heating. The degree of progress of the reaction can be confirmed by a decrease in the acid value of the reactant, and the reaction may be stopped when the stoichiometric end point of the reaction or the vicinity thereof is reached.

In the present specification, rosin is a general term for resin acids obtained from trees, and the main component is a substance derived from natural products including abietic acid, which is one of tricyclic diterpenes, and isomers thereof. Specific components include, for example, parastrinic acid, neoabietic acid, pimaric acid, dehydroabietic acid, isopimaric acid, sandaracopimalic acid in addition to abietic acid, and the rosin used in this embodiment is a mixture thereof. .
Rosin is roughly classified into three types according to the collection method: tall rosin with pulp as raw material, gum rosin with raw pine oil as raw material, and wood rosin with raw material as pine stump. Since the rosin used in this embodiment is easily available, gum rosin or tall rosin is desirable.
It is desirable to purify these rosins, and to remove high molecular weight substances thought to have arisen from the peroxide of the resin acid contained in the unpurified rosin and unsaponifiable substances contained in the unpurified rosin. To obtain purified rosin. The purification method is not particularly limited, and may be selected from various known purification methods.

  In the present specification, the purified rosin is obtained by subjecting rosin to purification treatment and contains abietic acid as a main component.

  In the present specification, disproportionated rosin is one in which unstable conjugated double bonds in the molecule are eliminated by heating rosin in the presence of a disproportionation catalyst, and mainly dehydroabietic acid and dihydro A mixture of abietic acid.

  The disproportionated rosin is obtained, for example, by heating an unpurified rosin or a purified rosin in the presence of a disproportionation catalyst. Examples of the disproportionation catalyst include known catalysts such as supported catalysts such as palladium carbon, rhodium carbon and platinum carbon, metal powders such as nickel and platinum, iodides such as iodine and iron iodide, and phosphorus compounds. The catalyst is usually used in an amount of 0.01% by mass or more and 5% by mass or less, preferably 0.01% by mass or more and 1% by mass or less, and the reaction temperature is 100 ° C. or more and 300 ° C. or less, preferably 150%. It is at least 290 ° C.

The hydrogenated rosin is, for example, unpurified rosin or purified rosin in the presence of a hydrogenation catalyst, usually under a pressure of hydrogen of 10 kg / cm ² or more and 200 kg / cm ² or less, preferably 50 kg / cm ² or more and 150 kg / cm ² or less. Obtained by heating at. Examples of the hydrogenation catalyst include known catalysts such as supported catalysts such as palladium carbon, rhodium carbon and platinum carbon, metal powders such as nickel and platinum, and iodides such as iodine and iron iodide. The catalyst is usually used in an amount of 0.01% by mass or more and 5% by mass or less, preferably 0.01% by mass or more and 1% by mass or less, and the reaction temperature is 100 ° C. or more and 300 ° C. or less, preferably 150%. It is at least 290 ° C.

  The rosin used in this embodiment may be a polymerized rosin obtained by polymerizing rosin, an unsaturated carboxylic acid-modified rosin obtained by adding an unsaturated carboxylic acid to rosin, or a phenol-modified rosin. Examples of the unsaturated carboxylic acid used for the preparation of the unsaturated carboxylic acid-modified rosin include maleic acid, maleic anhydride, fumaric acid, acrylic acid, and methacrylic acid.

  Although the exemplary compounds (1) to (20) of the specific rosin diol in the present embodiment are shown below, the present embodiment is not limited to these.

  The specific polyester of this embodiment may be configured using a dialcohol component other than the specific rosin diol. The content of the specific rosin diol in the specific polyester of this embodiment is preferably 10 mol% or more and 100 mol% or less, more preferably 20 mol% or more and 90 mol% or less in the dialcohol component from the viewpoint of chargeability.

  At least one selected from the group consisting of a disproportionated rosin ester group-containing rosin diol, a purified rosin ester group-containing rosin diol, an aliphatic diol, and an etherified diphenol is used as the dialcohol component other than the specific rosin diol. You may use in the range which does not drop.

  Examples of the disproportionated rosin ester group-containing rosin diol and the purified rosin ester group-containing rosin diol include compounds described in Japanese Patent Nos. 5267701 and 5267702.

  Examples of the aliphatic diol include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3 -Butanediol, 1,4-butenediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 2-ethyl-2-methylpropane-1,3-diol, 2- Butyl-2-ethylpropane-1,3-diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-1, 5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1, -Nonanediol, 1,10-decanediol, 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2-dimethylpropanoate, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol Etc. These aliphatic diols may be used alone or in combination of two or more.

  Etherified diphenol is a diol obtained by addition reaction of bisphenol A and alkylene oxide. Examples of the alkylene oxide include ethylene oxide and propylene oxide. The average added mole number of the alkylene oxide is 1 of bisphenol A. What is 2 mol or more and 16 mol or less with respect to mol is desirable.

  The specific polyester of the present embodiment may be configured using a trivalent or higher polyol as long as the effects of the present embodiment are not impaired. Examples of the trivalent or higher polyol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and the like. These may be used alone or in combination of two or more. As the trivalent or higher polyol, glycerin and trimethylolpropane are desirable from the viewpoint of availability and reactivity.

  In the present embodiment, examples of the dicarboxylic acid used for the synthesis of the polyester include at least one selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids. For example, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid; oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid , Glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dimer acid, alkyl succinic acid having 1 to 20 carbon atoms having a branched chain, alkenyl having an alkenyl group having 1 to 20 carbon atoms having a branched chain Aliphatic dicarboxylic acids such as succinic acid; anhydrides of these acids and alkyl (1 to 3 carbon atoms) esters of these acids. Among these, aromatic carboxylic acids such as isophthalic acid and terephthalic acid, and aliphatic carboxylic acids such as succinic acid, sebacic acid and azelaic acid from the viewpoint of toner durability and fixing properties, dispersibility of colorants, and availability. Acid is desirable.

  These aromatic carboxylic acids and aliphatic carboxylic acids may be used alone or in combination of two or more. In addition, trivalent or higher aromatic carboxylic acids may be used as long as the effects of the present embodiment are not impaired. Examples of trivalent or higher valent aromatic carboxylic acids include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, and anhydrides thereof, which are used alone. Also, two or more kinds may be used in combination. The trivalent or higher aromatic carboxylic acid is preferably trimellitic anhydride from the viewpoint of availability and reactivity.

  The specific polyester of this embodiment is prepared by a known and commonly used production method using an acid component and an alcohol component as raw materials. As the reaction method, either a transesterification reaction or a direct esterification reaction can be applied. Further, polycondensation may be promoted by a method of increasing the reaction temperature by pressurization, a method of reducing the pressure, or a method of flowing an inert gas under normal pressure. Depending on the reaction, a known and commonly used reaction catalyst such as at least one metal compound selected from antimony, titanium, tin, zinc, aluminum and manganese may be used to accelerate the reaction. The addition amount of these reaction catalysts is preferably 0.01 parts by mass or more and 1.5 parts by mass or less, more preferably 0.05 parts by mass or more and 1.0 parts by mass or less, with respect to 100 parts by mass of the total amount of the acid component and the alcohol component. desirable. The reaction temperature is, for example, a temperature of 180 ° C. or higher and 300 ° C. or lower.

The softening temperature of the specific polyester of the present embodiment is preferably 80 ° C. or higher and 160 ° C. or lower, and more preferably 90 ° C. or higher and 150 ° C. or lower, from the viewpoints of toner fixability, storage stability, and durability.
The glass transition temperature of the specific polyester of the present embodiment is preferably 35 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 50 ° C. or higher, from the viewpoints of low-temperature fixability, storage stability, and durability of the toner. The upper limit is preferably 80 ° C. or lower, more preferably 70 ° C. or lower, and further preferably 65 ° C. or lower.
The softening temperature and glass transition temperature of the specific polyester of this embodiment can be adjusted by adjusting the monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

  The acid value of the specific polyester according to the exemplary embodiment is preferably 3 mgKOH / g or more and 20 mgKOH / g or less, more preferably 5 mgKOH / g or more and 18 mgKOH / g or less, and 9 mgKOH / g or more and 16 mgKOH / g or less from the viewpoint of toner chargeability. Is more desirable.

The weight average molecular weight (Mw) of the specific polyester of this embodiment is preferably 10,000 or more and 100,000 or less, and more preferably 30,000 or more and 80,000 or less, from the viewpoint of chargeability, cleaning properties, and low-temperature fixability of the toner. More desirable.
The number average molecular weight (Mn) of the specific polyester of this embodiment is preferably 3,000 or more and 10,000 or less, and 4,000 or more and 8,000 or less from the viewpoint of chargeability, cleaning properties, and low-temperature fixability of the toner. More desirable.

  The specific polyester of this embodiment may be a modified polyester. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Polyester.

  By using the specific polyester of this embodiment as a binder resin for toner, a toner having excellent fixability is obtained. To the toner of the present embodiment, a known binder resin, for example, a vinyl resin such as styrene-acrylic resin, an epoxy resin, a polycarbonate, a polyurethane, or the like is used in combination as long as the effects of the present embodiment are not impaired. However, the content of the specific polyester of this embodiment is desirably 70% by mass or more, more desirably 90% by mass or more, and further desirably substantially 100% by mass in the binder resin.

<Toner for electrostatic image development>
The electrostatic image developing toner (also referred to as “toner”) according to the present embodiment contains the specific polyester of the present embodiment, and if necessary, a polyester other than the specific polyester (hereinafter referred to as “second polyester”). )), Other binder resins, colorants, release agents, charge control agents, external additives, and the like.

The second polyester used in the present embodiment is an amorphous or crystalline polyester, and includes a condensation polymer of a known polyvalent carboxylic acid and a known polyhydric alcohol.
As the second polyester, a crystalline polyester resin is desirable, and in particular, a polycondensation product of an aliphatic dicarboxylic acid (including its acid anhydride and acid chloride) and an aliphatic diol from the viewpoint of realizing low-temperature fixability. It is good that it is.

  Examples of the aliphatic diol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,4-butenediol, neopentyl glycol, 1 , 5-pentane glycol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogen Additive bisphenol A etc. are mentioned.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutamic acid. N-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, acid anhydrides or acid chlorides thereof.

Examples of the crystalline second polyester include a polyester that is a condensation polymer of 1,4-cyclohexanedimethanol and adipic acid, a polyester that is a condensation polymer of 1,6-hexanediol and sebacic acid, and ethylene glycol. Polyesters which are condensation polymers of succinic acid and succinic acid, polyesters which are condensation polymers of ethylene glycol and sebacic acid, and polyesters which are condensation polymers of 1,4-butanediol and succinic acid. Also preferred is polyester which is a condensation polymer of 1,4-cyclohexanedimethanol and adipic acid.
As the crystalline second polyester, for example, a polyester that is a condensation polymer of 1,10-decanediol and sebacic acid, or a polyester that is a condensation polymer of 1,9-nonanediol and dodecanoic acid is also suitable. Of these, polyesters obtained by reacting 1,9-nonanediol with dodecanoic acid are the best.

  The weight average molecular weight of the second polyester is preferably 5,000 or more and 50,000 or less, and more preferably 10,000 or more and 20,000 or less.

When the second polyester is crystalline, the melting temperature thereof is, for example, 50 ° C. or higher and 100 ° C. or lower, and preferably 60 ° C. or higher and 80 ° C. or lower.
The melting temperature is a value obtained as a peak temperature of an endothermic peak obtained by differential scanning calorimetry (DSC). The crystalline polyester resin may show a plurality of melting peaks, but in the present embodiment, the maximum peak is regarded as the melting temperature.

The content of the second polyester is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the total binder resin.
The content ratio of the second polyester to the first polyester (specific polyester) (second polyester / first polyester) is desirably 0.01 or more and 0.25 or less, and 0.05 or more and 0.18. The following is more desirable.

-Colorant-
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Pigments such as malachite green oxalate; acridine, xanthene, azo, benzoquinone , Azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo dyes, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, dye thiazole like; and the like. A colorant may be used individually by 1 type and may use 2 or more types together.

  As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant.

  The content of the colorant is desirably 1% by mass or more and 30% by mass or less of the toner particles, and more desirably 3% by mass or more and 15% by mass or less.

-Release agent-
Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. And so on. The release agent is not limited to this.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature of the release agent is determined by the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Method for measuring the transition temperature of plastic” from the DSC curve obtained by differential scanning calorimetry (DSC). Ask.

  The content of the release agent in the toner particles is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less.

-Other additives-
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner particles as internal additives.

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

Various average particle diameters and various particle size distribution indexes of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman-Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman-Coulter).
In the measurement, 0.5 mg to 50 mg of a measurement sample is added to 2 ml of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is obtained using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the measured particle size distribution, and the cumulative particle size of 16% is the volume particle size D16v. D16p, the particle size that is 50% cumulative is defined as the volume average particle size D50v, the number average particle size D50p, and the particle size that is cumulative 84% is defined as the volume particle size D84v and the number particle size D84p.
Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

  The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.

The shape factor SF1 is obtained by the following equation.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.
Specifically, the shape factor SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope image using an image analyzer, and is calculated as follows. That is, by capturing an optical microscope image of particles dispersed on the surface of a slide glass into a Luzex image analyzer using a video camera, obtaining the maximum length and projected area of 100 particles, calculating by the above formula, and obtaining the average value can get.

(External additive)
Examples of the external additive include inorganic particles. As the inorganic particles, SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO. _{SiO 2, K 2 O · (} TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like.

The surface of the inorganic particles as an external additive is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the hydrophobizing agent is, for example, 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the inorganic particles.

  Examples of external additives include resin particles (resin particles such as polystyrene, PMMA, and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, particles of a fluorine-based high molecular weight substance), and the like. Can be mentioned.

  The external additive amount of the external additive is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2% by mass or less with respect to the toner particles.

[Toner Production Method]
The toner according to the exemplary embodiment may be produced by producing toner particles, and the toner particles may be used as a toner, or an external additive may be externally added to the toner particles.

  The toner particles may be produced by any of a dry production method (for example, a kneading pulverization method) and a wet production method (for example, an aggregation coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). There is no restriction | limiting in particular in these manufacturing methods, A well-known manufacturing method is employ | adopted. Among them, it is desirable to obtain toner particles by an aggregation coalescence method.

Specifically, for example, when toner particles are produced by an aggregation coalescence method,
A step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation step); and a dispersion in which other particle dispersions are also mixed in the resin particle dispersion (if necessary) A process of aggregating resin particles (and other particles as necessary) to form aggregated particles (aggregated particle formation process); heating the aggregated particle dispersion in which the aggregated particles are dispersed, and aggregating The toner particles are manufactured through a step of fusing and coalescing the particles to form toner particles (fusing and coalescing step).

  Hereinafter, the detail of each process of the aggregation coalescence method is demonstrated. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described. The colorant and the release agent are used as necessary. Of course, you may use other additives other than a coloring agent and a mold release agent.

-Preparation step of resin particle dispersion-
First, for example, a colorant dispersion in which colorant particles are dispersed and a release agent dispersion in which release agent particles are dispersed are prepared together with a resin particle dispersion in which resin particles to be a binder resin are dispersed.

  The resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

Examples of the dispersion medium used for the resin particle dispersion include an aqueous medium.
Examples of the aqueous medium include water such as distilled water and ion exchange water; alcohols. These may be used individually by 1 type and may use 2 or more types together.

Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an anionic surfactant and a cationic surfactant are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.
Surfactant may be used individually by 1 type and may use 2 or more types together.

  As a method for dispersing the resin particles in the dispersion medium, for example, a general dispersion method using a rotary shearing homogenizer, a ball mill having media, a sand mill, a dyno mill, or the like can be given. Depending on the type of the resin particles, the resin particles may be dispersed in the dispersion medium using, for example, a phase inversion emulsification method. The phase inversion emulsification method is a method in which a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, neutralized by adding a base to the organic continuous phase (O phase), and then water (W phase). Is used to perform phase inversion from W / O to O / W and disperse the resin in an aqueous medium in the form of particles.

The volume average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less. .
The volume average particle size of the resin particles is a volume with respect to a divided particle size range (channel) using a particle size distribution obtained by measurement with a laser diffraction particle size distribution measuring apparatus (for example, LA-700 manufactured by Horiba, Ltd.). A cumulative distribution is drawn from the side of the small particle diameter, and the particle diameter of 50% in volume with respect to all particles is defined as the volume average particle diameter D50v. The volume average particle size of particles in other dispersions is also measured in the same manner.

  5 mass% or more and 50 mass% or less are preferable, and, as for content of the resin particle contained in the resin particle dispersion liquid, 10 mass% or more and 40 mass% or less are more preferable.

  Similar to the resin particle dispersion, for example, a colorant dispersion and a release agent dispersion are also prepared. That is, the dispersion medium, the dispersion method, the volume average particle diameter of the particles, and the content of the particles in the resin particle dispersion are the same in the colorant dispersion and the release agent dispersion.

-Aggregated particle formation process-
Next, the resin particle dispersion, the colorant dispersion, and the release agent dispersion are mixed.
Then, in the mixed dispersion, resin particles, colorant particles, and release agent particles are hetero-aggregated to have resin particles, colorant particles, and release agent particles having a diameter close to the diameter of the target toner particles. Aggregated particles are formed.

Specifically, for example, a flocculant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, pH 2 to 5), and a dispersion stabilizer is added as necessary. The glass particles are heated to a temperature close to the glass transition temperature (specifically, for example, the glass transition temperature of the resin particles is −30 ° C. or higher and the glass transition temperature is −10 ° C. or lower), and the particles dispersed in the mixed dispersion are agglomerated. To form aggregated particles.
In the agglomerated particle forming step, for example, the agglomerated agent is added at room temperature (for example, 25 ° C.) while stirring the mixed dispersion with a rotary shear homogenizer, and the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5) In addition, heating may be performed after adding a dispersion stabilizer as necessary.

Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant contained in the mixed dispersion, such as an inorganic metal salt and a bivalent or higher-valent metal complex. When a metal complex is used as the flocculant, the amount of the flocculant used is reduced and the charging characteristics are improved.
An additive that forms a complex or similar bond with the metal ion of the flocculant may be used together with the flocculant. As this additive, a chelating agent is preferably used.

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salts such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide Polymer; and the like.
A water-soluble chelating agent may be used as the chelating agent. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); .
For example, the addition amount of the chelating agent is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass with respect to 100 parts by mass of the resin particles.

-Fusion / unification process-
Next, the agglomerated particle dispersion in which the agglomerated particles are dispersed is heated to, for example, a glass transition temperature or higher of the resin particles (for example, a temperature of 10 ° C. to 30 ° C. higher than the glass transition temperature of the resin particles). Are fused and united to form toner particles.

Through the above steps, toner particles are obtained.
In addition, after obtaining the aggregated particle dispersion liquid in which the aggregated particles are dispersed, the aggregated particle dispersion liquid and the resin particle dispersion liquid in which the resin particles are dispersed are further mixed, and the resin particles are further added to the surface of the aggregated particles. A process of aggregating to adhere to form second aggregated particles, and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles. The toner particles may be manufactured through a step of forming toner particles having a core / shell structure.

After completion of the coalescence / union process, the toner particles formed in the solution are subjected to a known washing process, solid-liquid separation process, and drying process to obtain dried toner particles.
In the washing step, it is preferable to sufficiently perform substitution washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, or the like is preferably performed from the viewpoint of productivity. Also, the drying process is not particularly limited, but from the viewpoint of productivity, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying, or the like is preferably performed.

  The toner according to the exemplary embodiment is manufactured, for example, by adding an external additive to the dry toner particles and mixing them. Mixing is preferably performed by, for example, a V blender, a Henschel mixer, a Ladyge mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibration classifier, a wind classifier, or the like.

<Electrostatic image developer>
The electrostatic charge image developer according to the exemplary embodiment includes at least the toner according to the exemplary embodiment. The electrostatic charge image developer according to this embodiment may be a one-component developer including only the toner according to this embodiment, or may be a two-component developer in which the toner and a carrier are mixed.

  There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. Examples of carriers include a coated carrier in which the surface of a core made of magnetic powder is coated with a resin; a magnetic powder-dispersed carrier in which magnetic powder is dispersed in a matrix resin; and a porous magnetic powder impregnated with resin. Resin impregnated type carriers; and the like. The magnetic powder-dispersed carrier and the resin-impregnated carrier may be carriers in which the constituent particles of the carrier are used as a core and the surface is coated with a resin.

  Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; magnetic oxides such as ferrite and magnetite.

  Examples of the conductive particles include metals such as gold, silver, and copper; particles such as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

  Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include an acid copolymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin. The coating resin and the matrix resin may contain an additive such as a conductive material.

  In order to coat the surface of the core material with a resin, a method of coating with a coating layer forming solution in which a coating resin and various additives (used as necessary) are dissolved in an appropriate solvent may be mentioned. The solvent is not particularly limited, and may be selected in consideration of the type of resin used, application suitability, and the like. Specific resin coating methods include a dipping method in which a core material is immersed in a coating layer forming solution; a spray method in which the coating layer forming solution is sprayed on the surface of the core material; A fluidized bed method in which a coating layer forming solution is sprayed; a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater, and then the solvent is removed;

  The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, and more preferably 3: 100 to 20: 100.

<Image Forming Apparatus / Image Forming Method>
An image forming apparatus and an image forming method according to the present embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, and an electrostatic charge. Development means for containing an image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, and the toner image formed on the surface of the image carrier as a recording medium Transfer means for transferring to the surface of the recording medium, and fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic charge image developer according to this embodiment is applied as the electrostatic charge image developer.

  In the image forming apparatus according to this embodiment, a charging process for charging the surface of the image carrier, an electrostatic charge image forming process for forming an electrostatic image on the surface of the charged image carrier, and an electrostatic charge according to this embodiment. A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with an image developer; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the recording medium; An image forming method (an image forming method according to the present embodiment) including a fixing step of fixing the toner image transferred onto the surface of the recording medium is performed.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member An intermediate transfer type apparatus that primarily transfers the toner image transferred to the surface of the intermediate transfer body and then secondary transfer the toner image to the surface of the recording medium; after the toner image is transferred, the surface of the image carrier before charging is cleaned. A known image forming apparatus such as an apparatus provided with a cleaning unit; an apparatus provided with a charge removing unit that discharges the surface of the image holding member with a discharge light before charging after transferring the toner image;
In the case where the image forming apparatus according to this embodiment is an intermediate transfer type apparatus, for example, the transfer unit intermediately transfers an intermediate transfer body on which a toner image is transferred onto the surface and a toner image formed on the surface of the image holding body. A configuration having primary transfer means for primary transfer onto the surface of the body and secondary transfer means for secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium is applied.

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge that accommodates the electrostatic charge image developer according to this embodiment and includes a developing unit is preferably used.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited to this. In the following description, the main part shown in the figure will be described, and the description of other parts will be omitted.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first electrophotographic system that outputs an image of each color of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. To fourth image forming units 10Y, 10M, 10C, and 10K (image forming means). These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be process cartridges that can be attached to and detached from the image forming apparatus.

Above each unit 10Y, 10M, 10C, 10K, an intermediate transfer belt (an example of an intermediate transfer member) 20 is extended through each unit. The intermediate transfer belt 20 is provided around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20, and travels in a direction from the first unit 10Y to the fourth unit 10K. Yes. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer body cleaning device 30 is provided on the image holding surface side of the intermediate transfer belt 20 so as to face the drive roll 22.
Each unit 10Y, 10M, 10C, 10K developing device (an example of developing means) 4Y, 4M, 4C, 4K has yellow, magenta, cyan, black in toner cartridges 8Y, 8M, 8C, 8K, respectively. Each toner is supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, operation, and action, the yellow image disposed upstream in the intermediate transfer belt traveling direction is displayed here. The first unit 10Y to be formed will be described as a representative.

The first unit 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y for charging the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on a color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A primary transfer roll (an example of a primary transfer unit) 5Y that transfers a toner image onto the intermediate transfer belt 20, and a photoconductor cleaning device (an example of a cleaning unit) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer. Are arranged in order.
The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. A bias power source (not shown) for applying a primary transfer bias is connected to the primary transfer rolls 5Y, 5M, 5C, and 5K of each unit. Each bias power source changes the value of the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.
First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive base (for example, a volume resistivity of 1 × 10 ⁻⁶ Ωcm or less at 20 ° C.). This photosensitive layer usually has a high resistance (general resin resistance), but has a property of changing the specific resistance of the portion irradiated with the laser beam when irradiated with the laser beam. Therefore, the laser beam 3Y is irradiated from the exposure device 3 on the surface of the charged photoreceptor 1Y in accordance with yellow image data sent from a control unit (not shown). Thereby, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is developed and visualized as a toner image by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged electric charge on the photoreceptor 1Y, and has a developer roll (a developer holding member). Example) is held on. Then, as the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. The The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y acts on the toner image. The toner image on the photoreceptor 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the polarity (−) of the toner, and is controlled to, for example, +10 μA by the control unit (not shown) in the first unit 10Y.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

The primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 onto which the four color toner images have been transferred in multiple ways through the first to fourth units includes the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and an image holding surface of the intermediate transfer belt 20. To a secondary transfer portion composed of a secondary transfer roll (an example of secondary transfer means) 26 arranged on the side. On the other hand, recording paper (an example of a recording medium) P is fed at a predetermined timing into a gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism, and the secondary transfer bias is supplied to the support roll. 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, so The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detecting means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

  Thereafter, the recording paper P is sent to a pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image. .

Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. As the recording medium, in addition to the recording paper P, an OHP sheet and the like are also included.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. Preferably used.

  The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

<Process cartridge / toner cartridge>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment accommodates the electrostatic image developer according to the present embodiment, and develops the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer. And a process cartridge that can be attached to and detached from the image forming apparatus.

  The process cartridge according to the present embodiment is not limited to the above configuration, and is selected from a developing device and other means such as an image carrier, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one of the above may be provided.

  Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. In the following description, the main part shown in the figure will be described, and the description of other parts will be omitted.

FIG. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 2 is provided around the photoconductor 107 and the photoconductor 107 by, for example, a housing 117 provided with an attachment rail 116 and an opening 118 for exposure. A charging roller 108 (an example of a charging unit), a developing device 111 (an example of a developing unit), and a photoconductor cleaning device 113 (an example of a cleaning unit) are integrally combined and held to form a cartridge. Yes.
In FIG. 2, 109 is an exposure device (an example of an electrostatic charge image forming unit), 112 is a transfer device (an example of a transfer unit), 115 is a fixing device (an example of a fixing unit), and 300 is a recording paper (an example of a recording medium). Is shown.

Next, the toner cartridge according to this embodiment will be described.
The toner cartridge according to the present exemplary embodiment is a toner cartridge that accommodates the toner according to the present exemplary embodiment and is detachable from the image forming apparatus. The toner cartridge contains toner for replenishment to be supplied to the developing means provided in the image forming apparatus.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached. The developing devices 4Y, 4M, 4C, and 4K are toner cartridges corresponding to respective colors. And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

  Hereinafter, the present embodiment will be specifically described with reference to examples, but the present embodiment is not limited to the following examples. In the following, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

<Method for measuring physical properties of polyester resin>
[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
An apparatus HLC-8120GPC, SC-8020 (manufactured by Tosoh) and a column TSKgel SuperHM-H (6.0 mm ID × 15 cm × 2) (manufactured by Tosoh) were used, and THF (tetrahydrofuran) was used as an eluent. The measurement conditions were a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a temperature of 40 ° C., and detection was performed using an RI detector. The calibration curve is “Polystyrene standard sample TSK standard” manufactured by Tosoh: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”, “F-4”, “F”. It produced from 10 samples of "-40", "F-128", and "F-700".

[Acid value]
The acid value was measured according to the neutralization titration method described in JIS K0070. That is, an appropriate amount of sample was taken, 100 ml of a solvent (diethyl ether / ethanol mixed solution) and a few drops of an indicator (phenolphthalein solution) were added, and the mixture was shaken sufficiently until the sample was dissolved on a water bath. This was titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point was when the indicator was light red for 30 seconds. The acid value was calculated from the formula: A = (B × f × 5.611) / S. Here, A: acid value, B: amount of 0.1 mol / l potassium hydroxide ethanol solution used for titration (ml), f: factor of 0.1 mol / l potassium hydroxide ethanol solution, S: mass of sample (G).

[Glass-transition temperature]
Using a thermal analyzer DSC-20 (manufactured by Seiko Denshi Kogyo), 10 mg of a sample was heated at a constant rate of temperature increase (10 ° C./min) and measured.

[Percentage of total rosin ester groups]
The rosin used for the synthesis of rosin diol was analyzed, and the molar ratio of tetrahydroabietic acid, dihydroabietic acid and other abietic acids was determined. From this molar ratio and the composition ratio of rosin diol used for polyester synthesis, the ratio of the number of rosin ester groups derived from tetrahydroabietic acid and the number of rosin ester groups derived from dihydroabietic acid in the total rosin ester groups in the polyester The percentage was calculated.
The number ratio of rosin ester groups can be obtained by analyzing a sample obtained by hydrolyzing polyester by NMR or the like. The analytical value is approximately the same as the calculated value, although there may be a slight numerical difference due to the reaction rate of rosin diol and analytical errors.

<Synthesis of rosin diol>
[Hydrogenated rosin-derived rosindiol (1)]
97 parts of neopentyl glycol diglycidyl ether (Denacol EX211 manufactured by Nagase ChemteX) as bifunctional epoxy compound, 215 parts of hydrogenated rosin (FORAL AX manufactured by Pinova) as the rosin component, and tetraethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.4 parts are charged into a stainless steel reaction vessel equipped with a stirrer, a heating device, a cooling tube, and a thermometer, the temperature is raised to 160 ° C., and the ring-opening reaction between the carboxyl group of rosin and the epoxy group of the epoxy compound is carried out. went. The reaction was continued at the same temperature for 4 hours, and when the acid value reached 0.5 mg KOH / g, the reaction was stopped to obtain hydrogenated rosin-derived rosin diol.
The hydrogenated rosin used here is tetrahydroabietic acid: dihydroabietic acid: other abietic acids = 30: 60: 10 (molar ratio).
The hydrogenated rosin-derived rosin diol (1) includes exemplary compound (6) and exemplary compound (16).

[Hydrogenated rosin-derived rosindiol (2)]
97 parts neopentyl glycol diglycidyl ether (Nagase Chemtex Denacol EX211) as a bifunctional epoxy compound, 215 parts hydrogenated rosin (FORAL NC purified product from Pinova) as a rosin component, and tetraethylammonium bromide (Tokyo Chemical Industry) as a reaction catalyst 0.4 parts) was charged into a stainless steel reaction vessel equipped with a stirrer, heating device, cooling tube and thermometer, the temperature was raised to 160 ° C., and the ring opening of the carboxyl group of rosin and the epoxy group of the epoxy compound Reaction was performed. The reaction was continued at the same temperature for 4 hours, and when the acid value reached 0.5 mg KOH / g, the reaction was stopped to obtain hydrogenated rosin-derived rosin diol.
The hydrogenated rosin used here is tetrahydroabietic acid: dihydroabietic acid: other abietic acids = 40: 25: 35 (molar ratio).
The hydrogenated rosin-derived rosin diol (2) includes exemplary compound (6) and exemplary compound (16).

[Rosin rosin derived from disproportionated rosin]
Using disproportionated rosin (Disproportionated rosin manufactured by Wuzhou) instead of hydrogenated rosin, disproportionated rosin-derived rosin diol was synthesized in the same manner as the above-described synthesis of hydrogenated rosin-derived rosin diol.

[Purified rosin-derived rosin diol]
Using purified rosin obtained by subjecting gum rosin (Pine Crystal KR614, manufactured by Arakawa Chemical Industries, Ltd.) to purification (distillation conditions: 6.6 kPa, 220 ° C.) instead of hydrogenated rosin, In the same manner as in the synthesis, purified rosin-derived rosin diol was synthesized.

<Synthesis of polyester>
[Synthesis Example 1]
An acid component and an alcohol component shown in Table 1 and 0.3 part of tetra-n-butyl titanate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a reaction catalyst, a stirring device, a heating device, a thermometer, a fractionation device, and nitrogen gas introduction A stainless steel reaction vessel equipped with a tube was charged and subjected to a polycondensation reaction at 230 ° C. for 7 hours with stirring in a nitrogen atmosphere to synthesize polyester (1).
2 g of polyester (1) was taken and hydrolyzed by heating at 150 ° C. for 3 hours in 10 ml of deuterated dimethyl sulfoxide and 2 ml of a sodium methanol solution of sodium hydroxide (7N). Then, heavy water was added, ¹ H-NMR measurement was performed, and it was confirmed that the resin was constituted according to the charged values. Table 1 shows the measurement results of the molecular weight, acid value, and glass transition temperature of the polyester (1).

[Synthesis Examples 2 to 4]
Polyesters (2) to (4) were synthesized using the acid component and alcohol component shown in Table 1 in the same manner as in Synthesis Example 1. Table 1 shows the measurement results of the molecular weight, acid value, and glass transition temperature of the polyesters (2) to (4).

[Comparative Synthesis Examples 1 to 4]
Comparative polyesters (C1) to (C4) were synthesized in the same manner as in Synthesis Example 1 using the acid component and alcohol component shown in Table 1. Table 1 shows the measurement results of the molecular weight, acid value, and glass transition temperature of the polyesters (C1) to (C4).

<Example 1>
[Preparation of amorphous resin particle dispersion]
After putting 3000 parts of polyester (1), 10000 parts of ion-exchange water, and 90 parts of surfactant sodium dodecylbenzenesulfonate into an emulsification tank of a high-temperature / high-pressure emulsifier (Cabitron CD1010, slit 0.4 mm) After heating and melting, the dispersion was carried out at 110 ° C. and a flow rate of 3 L / min at 10,000 rpm for 30 minutes, passed through a cooling tank, and the resin particle dispersion was recovered to obtain an amorphous resin particle dispersion.

[Preparation of crystalline resin particle dispersion]
In a heat-dried three-necked flask, 160 parts of 1,9-nonanediol, 138 parts of 1,10-dodecanoic acid, and 0.05 part of dibutyltin oxide as a catalyst were added, and the air in the container was reduced by a vacuum operation. Was placed in an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 2 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 5 hours. When it became viscous, it was air-cooled, the reaction was stopped, and a crystalline polyester resin was synthesized. The melting temperature Tm of this resin was 74 ° C.
Thereafter, a crystalline resin particle dispersion was obtained using a high-temperature, high-pressure emulsification apparatus under the same conditions as the preparation of the amorphous resin particle dispersion.

[Preparation of colorant dispersion]
The following materials were mixed and dispersed for about 1 hour using a high-pressure impact disperser (HJP 30006 manufactured by Sugino Machine) to prepare a colorant dispersion (colorant concentration 20%, average particle size 0.13 μm).
・ Cyan pigment (Pigment Blue 15: 3 manufactured by Dainichi Seika Kogyo): 100 parts ・ Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku): 15 parts ・ Ion-exchanged water: 400 parts

[Preparation of release agent dispersion]
The following materials are mixed, heated, and dispersed using a homogenizer (Ultra Turrax T50, manufactured by IKA), then dispersed with a Menton Gorin high-pressure homogenizer (produced by Gorin), and a release agent dispersion (release agent). A concentration of 20% and an average particle size of 0.21 μm) were prepared.
・ Fatty acid ester (Nippon WEP-5): 50 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Neogen RK): 5 parts ・ Ion-exchanged water: 200 parts

[Production of toner particles]
The following materials are placed in a round stainless steel flask, dispersed using a homogenizer (Ultra Talax T50, manufactured by IKA), heated to 42 ° C. in a heating oil bath, held for 30 minutes, and then aggregated. When it was confirmed that the particles were formed, 100 parts of an additional amorphous resin particle dispersion was added, and the mixture was further held for 30 minutes.
Amorphous resin particle dispersion: 90 parts Crystalline resin particle dispersion: 10 parts Colorant dispersion: 50 parts Release agent dispersion: 60 parts 0.3M aqueous nitric acid solution: 50 parts Ion exchange Water: 500 parts

  Subsequently, nitrilotriacetic acid sodium salt (Chirest 70 manufactured by Chubu Kirest Co., Ltd.) was added so as to be 3% of the total liquid. Thereafter, a 1N aqueous sodium hydroxide solution was gently added until pH 7.2 was reached, and then the mixture was heated to 85 ° C. while maintaining stirring and maintained for 3 hours. Thereafter, the reaction product was filtered, washed with ion exchange water, and then dried using a vacuum dryer to obtain toner particles. When the particle size of the toner particles was measured with a Coulter Multisizer, the volume average particle size D50 was 3.9 μm, and the particle size distribution coefficient GSD was 1.22.

[Production of toner]
To 100 parts of toner particles, add 3 parts of silica particles (5% surface treatment with hexamethyldisilazane, average primary particle size 120 nm) obtained by the sol-gel method, and 1 part of silica particles (R972, manufactured by Nippon Aerosil). After a mixing process for 15 minutes at a peripheral speed of 30 m / sec using a Henschel mixer, coarse particles were removed using a sieve having an opening of 45 μm to obtain a toner.

[Production of developer]
As a carrier, ferrite (average particle size 50 μm) coated with methyl methacrylate / styrene copolymer was prepared. 7 parts of toner was added to 100 parts of the carrier and mixed with a tumbler shaker mixer to obtain a developer. The environmental conditions for mixing the toner and the carrier were two ways: summer environment (30 ° C., relative humidity 85%) and winter environment (5 ° C., relative humidity 10%).

<Examples 2-4, Comparative Examples 1-4>
Toner particles, a toner, and a developer were obtained in the same manner as in Example 1 except that the polyester (1) was changed to any one of the polyesters (2) to (4) and (C1) to (C4).

<Evaluation>
For Examples 1 to 4 and Comparative Examples 1 to 4, toners were evaluated as follows. The results are shown in Table 2.

[Low temperature fixability]
Developer was loaded into a modified machine from which the fixing device of DocuCenter Color 500 manufactured by Fuji Xerox was removed, and an unfixed image (solid image of 40 mm × 50 mm, toner carrying amount 0.5 mg / cm ² ) was formed on mirror-coated platinum paper.
The DocuCentreColor 500 fixing device was modified so that the fixing temperature was variable, and the image was fixed using this modified fixing device while increasing the fixing temperature stepwise from 130 ° C. by 5 ° C. step by step. The fixed image was observed with the naked eye, and the temperature at which the fixing offset disappeared was defined as the minimum fixing temperature. Fixing offset is a phenomenon in which an image defect occurs due to transfer of toner from an image to a member such as a fixing roller or a paper feed roller. The minimum fixing temperature is preferably 155 ° C. or lower, and more preferably 150 ° C. or lower.

[Chargeability]
Using a Toshiba blow-off charge measuring device, measure the charge amount (μC / g) of each toner for the developer mixed in the summer environment and the developer mixed in the winter environment, and determine the ratio between the two. It was. The closer the ratio of both is to 1, the more desirable result.
A: 0.65 or more B: 0.60 or more and less than 0.65 C: Less than 0.60

[Cleanability]
A developer was loaded into Fuji Xerox DocuCentreColor 500, and a full-scale halftone image having a density of 20% was formed on A4 size paper, and the last 100 images were observed with the naked eye.
A: No streaks or missing images are observed.
B: Slight streaks are observed.
C: Streaks and missing images are clearly recognized.

1Y, 1M, 1C, 1K, photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K, charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
28 Fixing device (an example of fixing means)
30 Intermediate transfer member cleaning device P Recording paper (an example of a recording medium)

107 photoconductor (an example of an image carrier)
108 Charging roll (an example of charging means)
109 Exposure apparatus (an example of electrostatic charge image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 photoconductor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Mounting rail 117 Housing 118 Opening 200 for exposure Process cartridge 300 Recording paper (an example of a recording medium)

Claims (9)

Phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipine At least one selected from the group consisting of acids, sebacic acid, azelaic acid, dimer acid, alkyl succinic acid having an alkyl group having 1 to 20 carbon atoms, and alkenyl succinic acid having an alkenyl group having 2 to 20 carbon atoms A dicarboxylic acid-derived repeating unit and a dialcohol-derived repeating unit represented by the following general formula (1):
A polyester resin for toner, wherein the content of the repeating unit derived from dialcohol represented by the following general formula (1) is 20% by mass or more and 50% by mass or less.

In general formula (1), R ¹ and R ² each independently represent hydrogen or a methyl group. L ¹ represents a divalent linking group selected from the group consisting of an ether group, a chain alkylene group, a cyclic alkylene group, and combinations thereof, and L ² and L ³ are each independently a carbonyl group, an ester group, Represents a divalent linking group selected from the group consisting of an ether group, a sulfonyl group, a chain alkylene group, a cyclic alkylene group, an arylene group, and combinations thereof, and the ring is represented by L ¹ and L ² or L ¹ and L ^3. It may be formed. A ¹ and A ² each independently represents a rosin ester group derived from hydrogenated rosin. The polyester resin for toner according to claim 1, which satisfies the following condition (1) and condition (2).
Condition (1): Tetrahydroabietic acid-derived rosin ester groups occupy 20% or more of all rosin ester groups.
Condition (2): The total of rosin ester groups derived from tetrahydroabietic acid and rosin ester groups derived from dihydroabietic acid accounts for 60% or more of the total rosin ester groups.   The polyester resin for toner according to claim 1, wherein the glass transition temperature is 65 ° C. or less.   A toner for developing an electrostatic charge image, comprising toner particles containing the polyester resin for toner according to any one of claims 1 to 3.   An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 4. Containing the electrostatic image developing toner according to claim 4;
A toner cartridge to be attached to and detached from the image forming apparatus. A developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 5;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: