JPS6278568A - Toner for developing electrostatic image - Google Patents

Abstract

PURPOSE:To provide a toner which has excellent offset preventive performance and excellent low-temp. fixability, hardly flocculates and is highly resistant to blocking by incorporating a polyester which is a non-linear polyester and of which the main chain has a long chain aliphat. hydrocarbon unit as a binder. CONSTITUTION:The polyester which is the non-linear polyester obtd. from a monomer component contg. a trihydric or higher hydric alcohol monomer and/or trihydric or higher hydric carboxylic acid monomer and of which the main chain has the long chain aliphat. hydrocarbon unit is used as the binder. The amt. of the trihydric or higher hydric alcohol to be used is preferably 1-30mol% by the total alcohol component. The ratio of the trihydric or higher hydric carboxylic acid monomer to be used is preferably 1-30mol% by the total acid component. The low-temp. fixability of the toner tends to be unsatisfactory if the ratio of use is excessive in either case. The non-linearization of the polyester is deficient and the offset preventive performance of the toner is unsatisfactory if the ratio of use is excessively low.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a toner for developing electrostatic latent images formed in electrophotography, electrostatic printing, electrostatic recording, etc. .

[Prior art]

For example, in electrophotography, an electrostatic latent image is usually formed on a latent image carrier made of a photoconductive photoreceptor by charging and exposure, and then this electrostatic latent image is developed with toner. After the toner image is transferred to a support such as transfer paper, it is fixed by heating, pressure, etc. to form a visible image.

Formation of a visible image via such an electrostatic image is preferably achieved at high speed, and from this point of view conventionally, thermal roller fixing, which has high thermal efficiency (and is more advantageous than other methods) in the fixing process, has been used. The method has been widely adopted.

However, in recent years, there has been a strong demand for even higher speeds, and in order to achieve this, it is essential to fix toner images at high speeds.

However, in order to fix a toner image at high speed in a hot roller fixing method, the toner used for development is required to have good low-temperature fixability. It is necessary to lower the softening point of However, if the softening point of the toner binder is lowered, part of the toner that makes up the image will transfer to the surface of the heat roller during fixing, and this will transfer again to the transfer paper that is sent next, staining the image. , the so-called offset phenomenon tends to occur more easily.

[Problem that the invention seeks to solve]

For this reason, monomers containing etherified bisphenol monomers, dicarboxylic acid monomers, trivalent or higher polyhydric alcohol monomers, and/or trivalent or higher polyvalent carboxylic acid monomers JP-A-57-37353 and JP-A-57-208559 have proposed a toner containing as a binder a non-linear polyester obtained from the following components.

Such technology uses etherified bisphenol monomer and dicarboxylic! 2!11. A polyester obtained by cross-crossing a linear polyester consisting of a 'fik body with a monomer component containing a trihydric or higher valent polyhydric alcohol monomer and/or a trivalent or higher valent polyhydric carboxylic acid monomer. The toner is made to have anti-offset performance by containing as a binder.

According to such toner, when performing continuous high-speed fixing at a fixing speed of 50 sheets/min or more on A3 size paper, for example, a large amount is transferred from the heat roller to the paper because the interval between sheets passing through the heat roller is extremely short. As a result, the temperature of the heat roller is significantly lowered, which causes the problem that some toners tend to be insufficiently fixed.

On the other hand, in order to improve the low-temperature fixing properties, it is possible to reduce the molecular weight of the binder and reduce the viscosity of the toner during fixing, but such measures also reduce the offset prevention performance of the toner, and furthermore, This has the problem that the toner tends to aggregate and has low blocking resistance, inhibiting the behavior of the toner as a unit particle and making it impossible to achieve good development.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to have excellent offset prevention performance, excellent low-temperature fixing properties, and to be able to satisfactorily achieve high-speed fixing. It is an object of the present invention to provide a toner for electrostatic image development that is resistant to agglomeration, has excellent blocking resistance, and can achieve good development.

[Means for solving problems]

The electrostatic image developing toner of the present invention is a non-linear polyester obtained from a monomer component containing a polyhydric alcohol monomer having a valence of 3 or more and/or a polyhydric carboxylic acid monomer having a valence of 3 or more. It is characterized in that it contains a polyester whose main chain has a long-chain aliphatic hydrocarbon unit as a binder.

According to such a toner, since the binder is a non-linear polyester whose main chain has a long-chain aliphatic hydrocarbon unit, the toner has excellent anti-offset performance and Since the toner has a low softening point, sufficient low-temperature fixing can be achieved, and furthermore, the decrease in the glass transition point Tg is suppressed, so that the toner has excellent anti-blocking properties and is less prone to agglomeration. Therefore, the toner can behave stably as a unit particle without agglomeration, and good development can be achieved.Furthermore, in fixing, the hot roller fixing method allows the toner to behave stably as a unit particle without causing an offset phenomenon at a sufficiently high speed. Good fixation can be achieved.

The present invention will be explained in detail below.

In the present invention, a non-linear polyester obtained from a monomer component containing a trihydric or higher polyhydric alcohol monomer and/or a trivalent or higher polyhydric carboxylic acid single star, the main chain of which is long. A toner for electrostatic image development is constructed by using a polyester containing a chain aliphatic hydrocarbon unit as a binder, and incorporating a coloring agent or additives as necessary into the binder.

The monomer components used in the synthesis of the polyester used as a binder in the present invention include the following (a) to (
The monomers shown in c) can be mentioned, and other monomers may be used if necessary.

(a) Divalent alcohol monomers and divalent carboxylic acid single stars as components that constitute the living body of the basic skeleton (bead chain) of polyester.

(b) Trivalent or higher polyhydric alcohol monomers and/or trivalent or higher polyvalent carboxylic acid monomers that participate in nonlinearization, that is, branching or network formation of polyester.

(c) A dihydric or higher alcohol monomer having a long chain aliphatic hydrocarbon unit to increase the number of long chain aliphatic hydrocarbon units constituting a part of the basic skeleton (main chain) of the polyester to six; / or a divalent or higher carboxylic acid monomer having the long-chain aliphatic hydrocarbon unit. In addition, the long chain in the long chain aliphatic hydrocarbon unit means that the number of carbon atoms constituting the straight chain is 3.
or more, preferably 3 to 30.

In particular, from the viewpoint of low-temperature fixability, those having 5 to 22 carbon atoms are preferred, and when those having an excessive number of carbon atoms are used, blocking resistance tends to decrease.

As the divalent alcohol monomer in (a) above,
Diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butynediol, neopentyl glycol, 1,4-butynediol; 1.4- Bis(hydroxymethyl)cyclohexane, bisphenol A, hydrogenated bisphenol A.

Examples include etherified bisphenol.

Among these, etherified bisphenol is particularly preferred, and specific examples include polyoxypropylene (2,
2) -2,2-bis(4'-hydroxyphenyl)propane, polyoxyethylene(2)-2,2-bis(4
゛-Hydroxyphenyl)propane, polyoxypropylene (6)-2,2-bis(4゛-hydroxyphenyl)propane, polyoxypropylene (1,3)-2,
Examples include 2-bis(4'-hydroxyphenyl)propane.

As the divalent carboxylic acid monomer in (a) above,
Examples include terephthalic acid, isophthalic acid, cyclohexanedicarboxylic acid, fumaric acid, maleic acid, citraconic acid, adipic acid, sebacic acid, and anhydrides or lower alkyl esters of these acids. Among these, aromatic dicarboxylic acid monomers are preferred, and by using this aromatic dicarboxylic acid monomer, a decrease in the glass transition point Tg of polyester can be suppressed.

Examples of such aromatic dicarboxylic acid monomers include terephthalic acid, isophthalic acid, cyclohexanedicarboxylic acid, and anhydrides or lower alkyl esters of these acids. The proportion of the aromatic dicarboxylic acid monomer used is preferably 30 mol % or more based on the entire acid component.

When the proportion of this aromatic dicarboxylic acid monomer is too small, the glass transition point Tg of the resulting polyester becomes too low, resulting in toner agglomeration that tends to be agglomerated, resulting in low blocking resistance and poor storage stability or developability. There are cases.

Examples of the trihydric or higher polyhydric alcohol monomer in (b) include sorbitol, 1,2,3.6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, Sucrose, 1,2,4-butanetriol, 1.2.
Examples include 5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3.5-trihydroxymethylbenzene. . The proportion of the polyhydric alcohol having a valence of 3 or more is preferably 1 to 30 mol % based on the total alcohol component. Non-linearity may be insufficient and the toner offset prevention performance may deteriorate.

Examples of the trivalent or higher polycarboxylic acid monomer in (b) above include 1,2,4-hexanetricarboxylic acid,
1,2.5-benzenetricarboxylic acid, l.

2,4-cyclohexanetricarboxylic acid, 2,5.7-
naphthalenetricarboxylic acid, 1,2.4-naphthalenetricarboxylic acid, 1,2.4-butanetricarboxylic acid, 1
．． 2.5-hexanetricarboxylic acid, 1.3-dicarboxyl-2-methyl-2-methylenecarboxylpropane, tetra(methylenecarboxyl)methane, 1.2,
7.8-Octane tetracarboxylic acid, embol trimer acid, anhydrides of these acids, etc.6
The proportion of the polyvalent carboxylic acid monomer having a valence of 3 or more is preferably 1 to 30 mol % based on the entire acid component. If the usage ratio is too high, the toner's low-temperature fixing properties tend to be insufficient.
If the proportion used is too small, the nonlinearity of the polyester may be insufficient, resulting in insufficient offset prevention performance of the toner.

2 having a long chain aliphatic hydrocarbon unit in the above (c)
Examples of alcohol monomers having higher valences include propylene glycol, 1,4-butanediol, 1,6-hexanediol, and the like. Also, the above (c)
Examples of the divalent or higher carboxylic acid monomer having a long-chain aliphatic hydrocarbon unit include glutaric acid, adipic acid, pimelic acid, superic acid, azelaic acid, and sebacic acid. These divalent or more alcohol monomers or divalent or more carboxylic acid monomers containing these long-chain aliphatic hydrocarbon units are added to the main chain of the nonlinear polyester in an amount of 1 to 60 moles of the constituent units of the main chain. %, preferably in the range from 5 to 50 mol %, of long chain aliphatic hydrocarbon units. If the proportion of long-chain aliphatic hydrocarbon units in the main chain of the nonlinear polyester is too small, sufficient low-temperature fixing properties may not be obtained in the toner, while if the S content is too large, the glass transition point 'Fg If the softening point is too low, the toner may tend to aggregate and have low blocking resistance, and at the same time, the softening point may also become too low, resulting in a decrease in the toner's anti-offset performance.

In the present invention, the main chain of the polyester used as the binder of the toner may contain, for example, an unsaturated aliphatic hydrocarbon unit in addition to the above-mentioned components. Monomers for introducing such unsaturated aliphatic hydrocarbon units include dihydric or higher alcohol monomers having unsaturated aliphatic hydrocarbon units and/or monomers having 2 or more unsaturated aliphatic hydrocarbon units. Examples of divalent or higher alcohol monomers having a carboxylic acid intermerium having a higher valence or higher, and an unsaturated aliphatic hydrocarbon unit in the former include butynediol, and the latter unsaturated aliphatic hydrocarbon unit. The carboxylic acid monomer having a valence of 2 or more and "ζ" can include fumaric acid, maleic acid, citraconic acid, mesaconic acid, itaconic acid, glutaconic acid, etc. These unsaturated aliphatic hydrocarbon units The monomer having the monomer is the sum of the unsaturated aliphatic hydrocarbon unit and the long chain aliphatic hydrocarbon unit (c),
One of the constituent units of the main chain is added to the main chain of the nonlinear polyester.
It is preferably used in proportions such that it will be present in the range 60 mol %, preferably 5 to 50 mol %.

When the proportion of unsaturated aliphatic hydrocarbon units is too large, the glass transition point "I'g" decreases too much, and the toner tends to aggregate, resulting in low blocking resistance. At the same time, the softening point also decreases. If the amount is too high, the toner offset prevention performance may deteriorate.

The electrostatic image developing toner of the present invention is a particle powder comprising a specific polyester as described above as a binder, and a coloring agent or additives used as necessary in the binder.

Examples of the colorant include carbon blank, nigrosine dye (C, 1, m50415B), aniline blue (C, 1, m50405), calco oil blue (C
, 1, Ugly azoec Blue3), Chrome Yellow (C, 1, It 14090), Ultramarine Blue (C, 1, m77103), DuPont Oil Red (C,
, 1,11k126105), quinoline yellow (C,
1, disease 47005), methylene blue chloride (C,
I.

52015), phthalocyanine blue (C, 1, patient 7)
4160), malachite green offsalate (C,1
, Kan 42000), lamp blank (C, 1, m77
266), Rose Hengar (C, 1, m45435),
Mixtures of these and others can be mentioned. It is preferable that these colorants are contained in an amount of 31 parts sufficient to form a visible image of sufficient l1 degree, and usually about 1 to 20 parts by weight per 100 parts by weight of the binder.

Examples of other additives include offset inhibitors, fluidity improvers, and charge control agents. Examples of the offset inhibitors include polyolefin waxes, carnauba wax, and alkylene bis fatty acid amide compounds. Examples of the fluidity improver include solica fine powder.

Further, when forming a magnetic toner, an IF material is contained in the binder together with or in place of the colorant. Such magnetic materials include metals or alloys that exhibit ferromagnetism such as iron, cobalt, and 2.7 Kel, including ferrite and magnetite, or compounds containing these elements, or compounds that do not contain ferromagnetic elements but are subjected to appropriate heat treatment. It is possible to use alloys that exhibit ferromagnetism by applying ferromagnetic properties, such as alloys called Heusler alloys containing manganese and copper such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, etc. can. These magnetic substances are uniformly dispersed in the binder in the form of fine particles with an average particle size of 0.1 to Ig. The content of the magnetic material is preferably 20 to 70 parts by weight, more preferably 40 to 70 parts by weight per 100 parts by weight of toner.

The electrostatic image developing toner of the present invention also has the ability to prevent the so-called toner filming phenomenon in which toner substances adhere to the surface of carrier particles or the surface of a latent image carrier and deteriorate these functions. A property improver may be included for the purpose of imparting various properties such as the ability to improve the pulverization property in the pulverization process, which is one of the normal toner manufacturing processes, or the ability to improve the triboelectric charging property of the toner. . As such a property improving agent, for example, a resin that is an uncrosslinked 1R aggregate and does not contain chloroform-insoluble matter can be preferably used. As such resin,
For example, styrenes such as styrene and parachlorostyrene; vinylnaphthalene: vinyl esters such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl henzoate, and vinyl butyrate; methyl acrylate, acrylic Ethyl acid, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-butyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid Methylene aliphatic carboxylic acid esters such as butyl; acrylonitrile; methacrylonitrile; acrylamide; vinyl ethers such as vinyl methyl ether, vinyl isobutyl ether, and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone;
N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; or a homopolymer obtained by polymerizing two or more of the above monomers. Copolymers obtained by combining and copolymerizing or mixtures of these homopolymers and copolymers, as well as non-vinyl thermoplastic resins such as rosin-modified phenol-formalin resins, oil-modified epoxy resins, polyurethane resins, cellulose resins, and polyether resins. Examples include non-vinyl resins, or mixtures of these and the above-mentioned vinyl resins.

These resins may be contained in a proportion of, for example, 90% by weight or less of the binder, as long as the effects of the present invention are not impaired.

According to the electrostatic image developing toner of the present invention, images can be formed using various developing methods. Specifically, for example, a magnetic brush of (a)-component or two-component developer is carried on a developer transporting carrier in a state where the layer I7 is larger than the gap in the developing area, and this magnetic brush is carried into the developing area. (b) A contact magnetic brush method in which development is carried out by adhering toner particles or particle groups in the magnetic brush to the electrostatic latent image while rubbing the electrostatic latent image with the magnetic brush.
- A magnetic brush of a component or two-component developer is supported on a developer transport carrier in a state where the layer thickness is smaller than the gap between the developing regions, and this magnetic brush is carried into the developing region, and the developing region is applied with, for example, an oscillating electric field. Jumping magnetic brush method, in which development is carried out by causing the toner particles or particle groups in the magnetic brush to fly and adhere to the electrostatic latent image, (c)
A developing method such as a cascade method can be applied.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited to these Examples.

(Manufacture of binder) (1) Binder A O polyoxypropylene (2,2)-2,2-bis(4
'-Hydroxyphenyl) Propane 688goSebacic acid 323g0Diisopropyl orthotitanate (esterification catalyst) 0.8g or more of the substance was transferred to an injector equipped with a thermometer, stainless steel stirrer, glass nitrogen gas inlet tube, and down-flow condenser. Place the flask in a round-bottomed flask with a volume of 4311, place the flask in a mantle heater, and use nitrogen gas from the nitrogen gas inlet tube to raise the temperature to 230°C while maintaining an inert atmosphere inside the flask. The reaction was carried out under stirring. When the water produced by the reaction stopped flowing out, the acid value was measured and found to be 1.5.

Furthermore, 38 g of 1.2.4-benzenetricarboxylic acid anhydride was added and reacted for about 8 hours until the acid value reached 1.
The reaction was terminated when the temperature reached 7.

The obtained resin was a pale yellow solid, and the softening point of this resin was measured with a Flow Tester CFT-500J (manufactured by LV+ Tsu Seisakusho) and was 125°C.

(2) Binder B Q polyoxypropylene (2,2)-2,2-bis(4
'-Hydroxyphenyl) propane 482go Polyoxyethylene (2)i, 2-bis(4'-hydroxyphenyl)propane 190go Terephthalic acid 133go Sebacic acid 182g0 Diisopropyl orthotitanate (esterification catalyst) 0.8g or more of the substance as a binder The reaction was carried out in the same manner as in the production of 1,2,4-benzenetricarboxylic acid anhydride 3.
8g was added and reacted for about 8 hours until the acid value reached 16.
The reaction was terminated when the

The obtained resin was a pale yellow solid, and the softening point of this resin was measured with a Flow Tester CFT-500J (manufactured by Shimabara Seisakusho) and was 124°C.

(3) Binder CO polyoxypropylene (2,2)-2,2-pis(4
'-Hydroxyphenyl) propane 482g0 Polyoxyethylene (2)-2,2-bis(4'-hydroxyphenyl)propane 190go Terephthalic acid 133go Adipic acid 77g0 Diisopropyl orthothicunate (esterification catalyst) 0.8g or more of the substance as a binder The reaction was carried out in the same manner as in the production of A, and further, 1,2,4-benzenetricarboxylic acid anhydride 3
8g was added and reacted for about 8 hours until the acid value reached 20.
The reaction was terminated when the

The obtained resin was a pale yellow solid, and the softening point of this resin was measured with a flow tester CFT-500J (manufactured by Shimabara Seisakusho) and was 128°C.

(4) Binder DO polyoxypropylene (2,2)-2,2-bis(4
゛-Hydroxyphenyl) propane 482goPolyoxyethylene(2)-2,2-bis(4'-hydroxyphenyl)propane 126g01.
6-hexanediol 24 g0 fumaric acid 174 gO diisopropyl orthotitanate (esterification catalyst) 0.8 g or more of the substance was reacted in the same manner as in the production of the binder, and further, 1.2.4-benzenetricarboxylic acid anhydride 7
7g was added and reacted for about 8 hours until the acid value reached 22.
The reaction was terminated when the

The obtained resin was a pale yellow solid, and the softening point of this resin was measured with a Flow Tester CFT-500J (manufactured by Shimabara Seisakusho) and was 125°C.

(5) Binder E O polyoxypropylene (2,2)-2,2-bis(4
'-Hydroxyphenyl) propane 619 go sebacic acid 404 gO diisopropyl orthotitanate (esterification catalyst) 0.8 g or more of the substance is reacted in the same manner as in the production of binder A,
Furthermore, 14 g of pentaerythritol was added and reacted for about 8 hours, and the reaction was terminated when the acid value reached 20.

The obtained resin is a pale yellow solid, and the softening point of this resin was measured using a flow tester CFT-5004 (manufactured by Shimabara Seisakusho).
When measured, the temperature was 130°C.

(6) Binder F (for comparison) 0 polyoxypropylene (2,2)-2,2-bis(4
-Hydroxyphenyl) propane 482goPolyoxyethylene (2)-2,2-bis(4'-hydroxyphenyl)propane 190goTerephthalic acid 120g0Diisopropyl orthotitanate (esterification catalyst) 0.8g The reaction was carried out in the same manner as in the production, and 138 g of 1,2.4-Hensentricarboxylic acid anhydride was added and the reaction was carried out for about 8 hours, and the reaction was terminated when the acid value reached 34.

The obtained resin was a pale yellow solid, and the softening point of this resin was measured with a flow tester CPR-500J (manufactured by Shimabara Seisakusho) and was 135°C.

(7) Binder G (for comparison) 0 polyoxypropylene (2,2) -2,2-bis(
4'-Hydroxyphenyl) Propane 688goTerephthalic acid 149g0Fumaru a
104g0 Diisopropyl orthotitanate (esterification catalyst) 0.8g or more of the material was reacted in the same manner as in the preparation of Binder A.

The obtained resin was a pale yellow solid, and the softening point of this resin was measured with a flow tester CFT-500J (manufactured by Shimabara Seisakusho) and was 107°C.

Example 1 Binder A 100-layer rack
Bomb black 10 parts by weight Example 2 Binder B 100 parts by weight Carbon black 10 parts by weight Example 3 Binder 0 100 parts by weight Carbon black 10 ffl parts by weight Example 4 Nender D 100 parts by weight Carbon black 10 parts by weight Example 5 Binder E 100 parts by weight Carbon black IO overlay part Example 6 Binder A 20 parts by weight Binder F 80 parts by weight Carbon blank 10 parts by weight Comparative example 1 Binder F (for comparison) 100! I! f
fi parts Carbon black 10 parts by weight Comparative Example 2 Binder G (for comparison) 100 parts by weight Carbon blank 1 offi Star parts In each of the Examples and Comparative Examples, materials of the indicated formulation were melted, kneaded, cooled, A toner consisting of particles with an average particle size of 10 μs was obtained by a conventional toner manufacturing method of pulverizing and classifying. The toners obtained in Examples 1 to 6 were
"Toner 1" to "Toner 6" respectively, and the toners obtained in Comparative Examples 1 and 2 were respectively designated as "Comparative Toner 1".
and "comparison toner 2".

For each of these toners, the minimum fixing temperature and offset generation temperature were determined, and the cohesiveness was also investigated.

Regarding the minimum fixing temperature, a backup is made of a heat roller whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by DuPont) and a rubber layer made of silicone rubber rKE-1300RTVJ (manufactured by Shin-Etsu Chemical Co., Ltd.) covered with a Teflon tube. Using an electrophotographic copying machine "U-Bix 5000J (manufactured by Konishiroku Photo Industries Co., Ltd.), which is equipped with a fixing device consisting of a roller, the linear speed of the heat roller was set to 200.
＋＊＋＊/second, and with the temperature of the heat roller initially set at 240°C, the toner image transferred to the 64g/cd transfer paper is continuously and repeatedly fixed at a temperature of 10°C. ℃ and relative humidity of 20% until the temperature of the heat roller drops to 140℃. The lowest temperature of the heat roller at which a fixed image exhibiting properties was obtained was defined as the lowest fixing temperature. Note that the fixing device used here has a solicone oil supply mechanism.

In addition, to measure the temperature at which offset occurs, the toner image is transferred in accordance with the measurement of the minimum fixing temperature, and then fixed using the above-mentioned fixing device, and then a blank transfer paper is sent to the fixing device under the same conditions. The operation of observing whether or not toner leakage occurs is repeated while the temperature of the heat roller of the fixing unit is successively lowered, and offset occurs at the lowest temperature of the heat roller when toner stains occur. Temperature.

Regarding blocking resistance, each sample was left for 48 hours at a temperature of 55°C and a relative humidity of 40%, and the presence or absence of aggregation and its degree were evaluated.

The above results are shown in Table 1.

In Table 1, "○" in the "blocking resistance" column.
"X" indicates that the blocking resistance is excellent and toner aggregation is less likely to occur, and "X" indicates that the blocking resistance is poor and toner aggregation is likely to occur.

As can be understood from the results in Table 1, toners 1 to 6 according to the present invention all have low minimum fixing temperatures, high offset generation temperatures, and excellent blocking resistance. As a result, the toner is less likely to aggregate and good development can be achieved, and good fixation can be achieved at a sufficiently high speed without causing image blurring.

Further, in toner 6, binder A used in the present invention
Although Binder F for comparison was also included, it was confirmed that the excellent effects of Binder A were fully exhibited.

On the other hand, Comparative Toner 1 has a polyester binder that does not have a long-chain aliphatic hydrocarbon unit in its main chain, so it has a high minimum fixing temperature and is not capable of high-speed fixing that is sufficient for practical use. cannot be achieved.

In addition, Comparative Toner 2 has anti-blocking properties because the polyester as a binder is composed of a filler component that does not contain a trihydric or higher polyhydric alcohol monomer and/or a trivalent or higher polyhydric carboxylic acid component. In addition, since the offset generation temperature is low, the image is likely to be stained due to the offset phenomenon, and as a result, it is difficult to achieve sufficiently high-speed fixing.

〔Effect of the invention〕

As explained above, according to the electrostatic image developing toner of the present invention, the binder contains a monomer containing a trihydric or higher polyhydric alcohol monomer and/or a trivalent or higher polyhydric carboxylic acid monomer. A non-green polyester obtained from body components,
Since the beads are made of polyester having long-chain aliphatic hydrocarbon units, the toner has excellent anti-offset performance and has a low softening point to achieve sufficient low-temperature fixing. Moreover, the decrease in the glass transition point Tg is suppressed, and the toner has excellent blocking resistance against agglomeration.

As a result, the toner is able to behave stably as unit particles without agglomeration, and good development can be achieved.Furthermore, in fixing, the hot roller fixing method allows the toner to behave stably as unit particles without causing any offset phenomenon and at a sufficiently high speed. good fixation can be achieved.

The reason why the electrostatic image developing toner of the present invention has such excellent properties as described above has not been strictly elucidated. Since it is a non-linear polyester whose main skeleton is an ester structure obtained from a AAA component containing the above-mentioned polyhydric carboxylic acid monomer, and a part of the skeleton is formed by long-chain aliphatic hydrocarbon units, It has a low softening point and can be fixed at a sufficiently low temperature. Part of the reason is thought to be that the toner has a property of being difficult to aggregate.

Claims (1)

[Claims] 1) Trivalent or higher polyhydric alcohol monomer and/or trihydric alcohol monomer
A non-linear polyester obtained from a monomer component containing a polycarboxylic acid monomer having a polyhydric acid monomer or higher, characterized in that it contains a polyester whose main chain has a long-chain aliphatic hydrocarbon unit as a binder. Toner for electrostatic image development.