JP3276915B2 - Electrostatic toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrostatic charge developing toner used in an image forming apparatus such as an electrophotographic method, an electrostatic recording method, and an electrostatic printing method. More specifically, a toner for electrostatic charge development having a wide non-offset temperature range, excellent low-temperature fixability, good flowability and storage stability, and capable of obtaining a uniform transfer image even after copying a large number of sheets. About.

[0002]

2. Description of the Related Art In an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like, an electrostatic image formed on a support (recording layer) is composed of toner particles containing a binder resin and a colorant as main components. Is visualized by This visible image is fixed on the support as it is, or is fixed after being transferred to an adherend such as paper. For this reason, the toner for electrostatic charge development is required to have not only developability but also good transferability and fixability. In recent years, copiers and printers using the electrophotographic method have become widespread, and are also spreading to ordinary households. In addition, multi-functionalization is progressing, and accordingly, there is an increasing demand for low-energy fixing for the purpose of reducing power consumption and simplifying a fixing mechanism. In recent copiers and printers, a contact heating system such as a hot roll has been widely adopted. This method has the advantages that the thermal efficiency is higher than that of the conventional method, the power of the fixing unit can be reduced, and the size can be reduced. In order to prevent the offset phenomenon, the toner used in this method requires the addition of a synthetic wax such as a low molecular weight paraffin wax / polyolefin wax or a vegetable wax such as carnauba wax as an anti-offset agent. . However, these conventional wax-based offset inhibitors have the following problems. For example, in the case of low molecular weight paraffin wax / polyolefin wax, the non-offset temperature width increases and the fixing strength tends to improve with an increase in the amount of addition. However, due to poor compatibility with the binder resin, these wax particles are exposed on the toner surface, deteriorating the fluidity of the toner, increasing the spent on the carrier,
The problem of fusion to the developing sleeve and the photoconductor is likely to occur. In the case of the vegetable wax, the offset does not occur even at a low temperature as the amount of addition increases, and the fixing strength tends to increase. However, since the releasability is inferior to that of the synthetic wax, the offset at a high temperature is deteriorated.
At the same time, the storage stability and fluidity of the toner deteriorate due to the large amount of the oligomer component. The toner having poor fluidity adheres to the inside of the pulverizing and classifying machine at the time of pulverizing and classifying, and significantly impairs productivity.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention has a wide non-offset temperature range, excellent low-temperature fixability, good flowability and storage stability, and can be used after copying a large number of sheets. Another object of the present invention is to provide a toner for electrostatic charge development capable of obtaining a uniform transferred image.

[0004]

[MEANS FOR SOLVING THE PROBLEMS] A polyester resin and
At least a copolymer represented by the formula (1) and a colorant
The problem described above is solved by the contained electrostatic charge developing toner.
And completed the present invention. (Wherein R is a hydrogen atom, a benzoic acid residue or a carbon atom number)
4 or less fatty acid residues;¹Is 11 or more carbon atoms
Represents an aliphatic group of k, m, and n indicate copolymerization ratios, and k is
0 to 0.60, m and n are both greater than 0
The value of n / (m + n) is in the range of 0.20 to 0.85
And k + m + n = 1.0. X is the average weight
Indicates the degree. )

Hereinafter, the present invention will be described in detail. In the present invention, the electrostatic charge developing toner is used to include both a one-component developing toner and a two-component developing toner. The copolymer of the present invention has the following formula (2)
And the fatty acid of the formula (3) can be synthesized by condensation. (In the formula, R represents a hydrogen atom, a benzoic acid residue or a fatty acid residue having 4 or less carbon atoms. K, m, and n represent a copolymerization ratio, and k is in a range of 0 to 0.60; m and n are both greater than 0, and the value of n / (m + n) is 0.20 to 0.8.
5 and k + m + n = 1.0. Also, x
Indicates an average degree of polymerization. R ¹ —COOH (3) (wherein, R ¹ represents an aliphatic group having 11 or more carbon atoms.) Further, a side chain component OCO is added to the radical polymerizable monomer.
It may be synthesized by radical polymerization by introducing R ^1, but the above condensation method is preferred because side reactions are easily suppressed. In the formula (3), the number of carbon atoms of the aliphatic group for R ¹ is more preferably 11 to 40.

The copolymer represented by the formula (1) has a number average molecular weight Mn in the range of 2,000 to 50,000. If Mn is less than 2,000, problems tend to occur in the storage characteristics of the toner. If it exceeds 50,000, the melt viscosity increases, so that the low-temperature fixability of the toner cannot be improved. Preferred Mn is 4,000 to 45,000, more preferably 1
It is in the range of 0000 to 40,000. The copolymerization ratio of ethylene, which is the main chain portion of the copolymer represented by the formula (1), that is, k in the formula (1) is in the range of 0 to 0.60.
When the ethylene copolymerization ratio exceeds 0.60, the endothermic peak temperature of a differential scanning calorimeter (hereinafter abbreviated as DSC) sharply decreases. Further, the copolymerization ratio m of the vinyl alcohol portion,
For n, the value of n / (m + n) indicates the degree of grafting and is in the range of 0.20 to 0.85. The preferred value of the grafting ratio is 0.30 to 0.85, more preferably 0.40 to 0.85. If the value of n / (m + n) is less than the lower limit of the above range, the melting start temperature of the copolymer increases, and the low-temperature fixability deteriorates. If the upper limit of the above range is exceeded, the crystallinity of the main chain portion of the copolymer due to intermolecular hydrogen atom bonding becomes high, so that the melting temperature and the thermal decomposition temperature become close to each other, making it difficult to produce the intended electrostatic charge developing toner. Become.

The side chain OCO of the copolymer represented by the formula (1)
R ¹ (R ¹ represents an aliphatic group having 11 or more carbon atoms) is a residue obtained by condensing the fatty acid represented by the formula (3). Further, the copolymer of the formula (1) preferably has a temperature difference between an endothermic peak temperature in a differential scanning calorimeter (DSC) and a melting start temperature in a Koka type flow tester of 50 ° C. or less, more preferably. 40 ° C. or lower, more preferably 35 ° C.
It is below ° C. If the temperature difference is larger than 50 ° C., the low-temperature fixability deteriorates. Further, the toner obtained by the present invention is
Fixing method is hot roll, heat belt, hot plate, flash,
And an image forming apparatus comprising a combination thereof.

The main chain portion of the copolymer represented by the formula (1), that is, the polymer represented by the formula (2) is a partially saponified polyvinyl alcohol, polyethylene vinyl alcohol and a precursor thereof. In this case, the partially saponified polyvinyl alcohol, polyethylene vinyl alcohol and their precursors have a number average molecular weight Mn of 2,000 or more and 5 or more.
Those having a glass transition temperature (hereinafter abbreviated as Tg) in DSC of not more than 000 are preferably 40 to 70 ° C. When the Tg of the polymer represented by the formula (2) is lower than 40 ° C., the selection range of the fatty acid represented by the formula (3) is limited in order to satisfy the storage stability of the toner. Tg is 7
If the temperature is higher than 0 ° C., the low-temperature fixability deteriorates, which is not preferable. The precursor may have a benzoic acid residue or a fatty acid residue having 4 or less carbon atoms as a substituent. The degree of polymerization x of the polymer is 200 to 1,000.
0, the partially saponified polyvinyl alcohol preferably has a saponification degree of 80 mol% or less, more preferably 70 mol% or less. When the degree of saponification of the partially saponified polyvinyl alcohol exceeds 80 mol%, the melting temperature of the partially saponified polyvinyl alcohol and the value of the thermal decomposition onset temperature are close to each other. Coalescence is likely to be uneven.

The polymer represented by the formula (2) may have a main chain portion composed of only partially saponified polyvinyl alcohol,
In that case, n = 0. The polymer is on the market,
Commercially available ones can also be used. Partially saponified polyvinyl alcohol is specifically obtained from Nippon Synthetic Chemical Company: Gosefimer NK-05, Gosefimer KP-08, etc., as well as from Denki Kagaku Kogyo Co., Ltd., Shin-Etsu Chemical Co., Unitika Chemical Co., Kuraray Co., Ltd. Polyethylene vinyl alcohol is commercially available from Kuraray Co., Ltd. in addition to Soarnol E3803 from Nippon Synthetic Chemical Co., Ltd., and those having the above characteristics can be used.

The fatty acids represented by the formula (3) used in the present invention include saturated and unsaturated fatty acids having 12 or more carbon atoms. Specifically, lauric acid, myristic acid,
Myristoleic acid, palmitic acid, palmitoleic acid,
Beef tallow which is a natural mixture thereof such as oleic acid, linoleic acid, linolenic acid (including α- and γ-), ricinoleic acid, stearic acid, 12-hydroxystearic acid, arachidic acid, behenic acid, erucic acid, lignoceric acid, etc. Fatty acids, tallow hardened fatty acids, palm oil fatty acids, palm oil hardened fatty acids, sugar fatty acids, vegetable oil fat fatty acids, fish oil hardened fatty acids, soybean hardened fatty acids, esterified products such as montanic acid derived from coal, etc. Can be used together. In addition, long-chain synthetic fatty acids are also commercially available from Petrolite under the trade name: UNISID up to a molecular weight of about 800 and can be used. When the unsaturated fatty acid among the fatty acids represented by the formula (3) is condensed and grafted, side reactions such as an oxidation reaction and a cross-linking reaction may occur. A side reaction can be prevented by adding a radical reaction inhibitor, an antioxidant, or the like, if necessary, but it is premised that the additive does not hinder the condensation reaction.

As the fatty acid represented by the formula (3), the above-mentioned saturated and unsaturated fatty acids can be used, but those having a melting point of 65 to 120 ° C. measured by DSC are preferred. The copolymer represented by the formula (1) of the present invention can be produced by any of a melting method and a solution method, and the polymer represented by the formula (2) and the fatty acid represented by the formula (3) are produced under a nitrogen atmosphere at 150 to By conducting the condensation reaction at 290 ° C., a copolymer represented by the formula (1) is obtained. The residue obtained by the condensation reaction of the fatty acid represented by the above formula (3) is represented by OCOR ¹ (R ¹ represents an aliphatic group having 11 or more carbon atoms) as a side chain component.

For the production of the copolymer represented by the formula (1), a catalyst used for esterification and transesterification can be used. For example, when the reactive group of the polymer represented by the formula (2) is a hydroxyl group, that is, when R is a hydrogen atom, a known esterification catalyst, specifically, lithium acetate, sodium acetate, magnesium acetate, Potassium acetate, calcium acetate, nickel acetate, cobalt acetate, barium acetate,
Manganese acetate and hydrates thereof are preferably used. When the reactive group is a lower ester typified by an acetate ester, that is, when R is a fatty acid residue having 1 to 4 carbon atoms or a benzoic acid residue, a known ester exchange reaction catalyst, specifically, Specifically, organic tin compounds such as dibutyltin oxide, organic titanium compounds such as titanium tetrapropoxide, zinc acetate and hydrates thereof are preferably used. Among the above catalysts, alkali metal acetates, alkaline earth metal acetates, and transition metal acetates are preferable because of their high reactivity, and more preferable catalysts are sodium acetate, potassium acetate, calcium acetate, magnesium acetate, barium acetate, and acetic acid. Zinc, nickel acetate,
Manganese acetate, cobalt acetate and their hydrates are used.

The toner for developing an electrostatic charge of the present invention contains at least a polyester resin, the above-mentioned copolymer and a colorant as main components, and appropriately contains additives that are added as necessary. Particles having an average particle size of 5 to 20 μm. An external additive composed of fine particles such as silica may be mixed with the particles obtained in this manner to form a toner for electrostatic charge development. The ratio of the copolymer of the formula (1) contained in the toner is determined based on the ratio of the polyester resin 1
1 to 60 parts by weight to 00 parts by weight is preferred. If the amount is less than 1 part by weight, not only no improvement in low-temperature fixing property is observed, but also an offset phenomenon easily occurs in a contact-type fixing machine such as a hot roll system, which is not preferable. If the amount exceeds 60 parts by weight, the dispersion of the polyester resin and other additives such as a colorant and a charge controlling agent in the copolymer tends to be non-uniform, and it is difficult to obtain a uniform image. Further, the mechanical strength of the toner is reduced, and the toner is pulverized when the toner is stirred in a developing machine for a long period of time, so that the image density is easily reduced and the fog is increased.
A more preferred content is 2 to 40 parts by weight. In some cases, a known release agent such as a low molecular weight paraffin wax, a polyolefin wax, or a vegetable wax may be contained in a range that does not cause any harm. Examples of the coloring agent include carbon black, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate lamp black, rhodamine B, quinacridone, and rose bengal. And mixtures thereof. These colorants need to be contained in a sufficient ratio to form a visible image with a sufficient density.

[0014] Other optional additives include a magnetic agent and an external additive. Examples of the release agent include natural waxes such as carnauba wax, candelilla wax and montan wax, synthetic hydrocarbon atom waxes such as low molecular weight polypropylene, low molecular weight polyethylene and Fischer-Tropsch wax, and synthetic ester waxes. Examples of the charge control agent include a positive charge control agent such as a nigrosine dye, a quaternary ammonium salt, a triphenylmethane type, a resin type, a pyridinium salt, and an azine; and a negative charge control type such as a chromium or iron type metal complex salt and a resin type. There are agents. Usually, 0.01 to 10 parts by weight is used per 100 parts by weight of the binder resin. Examples of the magnetic agent include iron oxide, ferrite, magnetite, and other ferromagnetic substances such as cobalt and nickel, and alloys that exhibit ferromagnetism by heat treatment such as Heusler alloys.
Magnetic powder having an average particle size of 1 μm or less is preferably used. The magnetic powder imparts magnetism to the toner to form a magnetic toner, and also has a coloring action and a polishing action, and is used as needed. The amount of the magnetic powder varies greatly depending on the developing system, but is usually used in the toner in an amount of 0.01 to 90% by weight. External additives include inorganic fine particles such as silica, titanium oxide, and alumina, fine resin particles, and magnetic powder.
Fine particles and magnetic powder having a diameter of not more than μm are preferably used, and inorganic particles having an average particle diameter of not more than 0.1 μm are more preferable. Silica, alumina, inorganic fine particles such as titanium oxide,
Those whose surfaces have been subjected to a hydrophobic treatment are more preferably used. Generally, these external additives are used with an expectation of an improvement in fluidity and storage stability and a polishing effect, and the amount of these additives is 0.01 to 3 parts by weight based on 100 parts by weight of the toner.

The toner of the present invention is used as a two-component developer or a one-component developer which is not mixed with a carrier by mixing with a carrier comprising iron particles, ferrite, granulated magnetite, resin particles containing magnetic powder, and the like. You. The carrier generally has an average particle size of 30 to 200 μm, and the carrier surface may be coated with an acrylic resin, a silicone resin, a fluororesin, or the like. The carrier subjected to the coating treatment is preferably used because the spent resistance is improved.

The electrostatic charge developing toner of the present invention is preferably used in a heat fixing system comprising at least a hot roll, a heat belt or a hot plate. The heat roll, the heat belt and the heat plate in contact with the toner of the fixing device are preferably those whose surfaces are treated with a resin having releasability such as a silicone resin or a fluororesin. Further, a small amount of a release agent such as silicone oil may be adhered to the surface of the fixing device in contact with the toner.

In the present invention, the endothermic onset temperature, endothermic peak temperature and Tg are DSC: DSC manufactured by Seiko Denshi Kogyo KK
Using -120, heating and quenching at 10 ° C./min were repeated twice, and the temperature was obtained from an endothermic curve at the time of the second heating. Tg is a midpoint value, which is the midpoint between the endothermic start temperature and the endothermic peak temperature. The melting start temperature and the flow softening point were measured by using a high rise type flow tester: CFT-500 manufactured by Shimadzu Corporation, and the plunger descent temperature under the following measurement conditions was calculated from the melting start temperature, the descent start temperature to the descent end temperature. The point was taken as the flow softening temperature. Measurement conditions; plunger: 1 cm ² die Diameter × length: 1 × 1 mm Load: 20 kgf Preheating temperature, time: 50-80 ° C., 300 seconds Heating rate: 6 ° C./min The molecular weight is measured by the osmotic pressure method. And polystyrene was used as a standard.

Hereinafter, the present invention will be described in more detail with reference to examples.

EXAMPLES Examples of the synthesis of the copolymer of the present invention are shown below. Synthesis Example 1 [Synthesis example using polyethylene vinyl alcohol and behenic acid (graft rate: 40 mol%)] In a 500 ml round bottom separable flask, polyethylene vinyl alcohol (trade name, manufactured by Nippon Synthetic Chemical Company; Soarnol E)
3803, Tg 58 ° C) 18.98 g, behenic acid (endothermic peak temperature 77 ° C) 42.35 g, and calcium acetate 0.80 g were added, and the contents were heated to 150 ° C under a nitrogen gas atmosphere to melt the contents. Next, while raising the temperature from 150 ° C. by 20 ° C. in increments of 20 ° C., a condensation reaction is performed at each temperature for 1 hour until the temperature reaches 270 ° C., and the reaction is performed at 270 ° C. until no by-product water and acetic acid are generated. 22 containers
The mixture was allowed to cool to 0 ° C. and the melt was taken out. The endothermic onset temperature of the obtained copolymer of the present invention is 53.2 ° C, the endothermic peak temperature is 60.2 ° C, the melting onset temperature is 71.4 ° C, the flow softening point is 89.2 ° C, and the melting onset temperature is The difference from the endothermic peak temperature is 11.2 ° C., Mn is 34,300, and the graft ratio is 4
It was 0 mol%.

Synthesis Example 2 [Synthesis example using polyethylene vinyl alcohol and behenic acid (graft rate: 60 mol%)] 18.98 g of polyethylene vinyl alcohol (trade name, manufactured by Nippon Synthetic Chemical Company; Soarnol E3803), 63.34 g of behenic acid, A copolymer of the present invention was obtained in the same manner as in Synthesis Example 1 except that calcium acetate was replaced with 1.26 g. The endothermic start temperature of the obtained copolymer is 53.1 ° C, the endothermic peak temperature is 60.6 ° C, the melting start temperature is 63.0 ° C, the flow softening point is 79.44 ° C, the melting start temperature and the endothermic peak temperature. Was 2.4 ° C., Mn was 44,200, and the grafting ratio was 60 mol%.

Synthesis Example 3 [Synthesis Example Using Polyethylene Vinyl Alcohol and Behenic Acid (Grafting Ratio: 40 mol%)] 55
g, catalyst: The reaction was carried out under melting in the same manner as in the synthesis example except that 1.61 g of calcium acetate was used until no by-product water was distilled off. The collected water was 97% of the theoretical amount. Further, the graft resin was pulverized in the same manner as in Synthesis Example 1, and the thermophysical properties were evaluated. The endothermic onset temperature by DSC was 53.7 ° C., the endothermic peak temperature was 60.1 ° C., the flow onset temperature by flow tester was 65.4 ° C., and the flow softening point was 79.2 ° C. Mn was 2,100.

[0021]

[Synthesis method of main chain resin] Ethylene vinyl acetate copolymer (copolymerization ratio: ethylene / vinyl acetate = 0.38 / 0.
62) Synthesis In a 1 L stainless steel autoclave equipped with a stirring blade, 100 ml of dehydrated methanol and 20.0 g of a vinyl acetate monomer distilled and purified by a conventional method were charged, and nitrogen gas was bubbled into this solution from a nitrogen inlet tube. After the dissolved oxygen has been sufficiently removed, benzoyl peroxide
After adding 0.01 g, an autoclave was assembled. Then, introduction and exhaust of nitrogen gas at 120 atm were repeated 5 times until the inside was completely replaced with nitrogen gas. further,
Ethylene gas is introduced from the inlet, and gas pressure is 45kgf
/ Cm ^2, and then reacted at 60 ° C. for 18 hours. After cooling to room temperature, remove residual gas,
The contents were poured into a large amount of water and precipitated. 35 g of a crude ethylene vinyl acetate copolymer was obtained. GPC analysis (solvent THF, column: Shodex KF-80M) was performed to evaluate the number average molecular weight in terms of polystyrene. As a result, Mn was 2,400, Mw was 4,200, and Mw / Mn was 1.75. Total amount of crude ethylene-vinyl acetate copolymer obtained by adjusting ethylene-vinyl alcohol copolymer: 35
g equipped with a reflux condenser and a mechanical stirrer.
L 3 neck round bottom separable flask, 5% NaOH
Then, 1 L of an ethanol / ethanol solution was added, and a saponification reaction was performed for 4 hours under reflux to deacetylate. Four times the amount of water was added to an alcohol solution of the ethylene vinyl alcohol copolymer to precipitate the ethylene vinyl alcohol copolymer. After filtration,
After repeated washing with water, the by-produced sodium acetate was sufficiently washed, and dried at 50 ° C. overnight. The yield was 24.0 g.

Using the copolymers obtained in the above Synthesis Examples 1 to 3, a toner for electrostatic charge development of the present invention was prepared according to the following composition and procedure. Example 1 100 parts by weight of polyester resin (product name FC-664, manufactured by Mitsubishi Rayon Co., Ltd.) 5 parts by weight of copolymer obtained in Synthesis Example 1 6 parts by weight of carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Corporation) 6 parts by weight Charge control 1 part by weight of the agent (trade name: TRH, manufactured by Hodogaya Chemical Industry Co., Ltd.) The above formulation was mixed with a Henschel mixer (manufactured by Mitsui Miike Industry Co., Ltd.). The mixture was kneaded with a twin-screw kneader to a temperature of about 14
After melt kneading at 5 ° C, jet pulverization
Airflow classification was performed to obtain toner particles having an average particle size of 9.2 μm.
0.5 parts by weight of hydrophobic silica (trade name: H2000 / 4, manufactured by Hoechst) was mixed with 100 parts by weight of the toner particles using a Henschel mixer to obtain a toner for electrostatic charge development of the present invention.

Examples 2-3 The procedure of Example 1 was repeated, except that the copolymer obtained in Synthesis Examples 1 and 2 was used instead of the copolymer obtained in Synthesis Example 1. 2-3 toners were obtained. Example 4 A toner was obtained in the same manner as in Example 1 except that the amount of the copolymer in Synthesis Example 1 was changed to 20 parts by weight and kneading was performed so that the temperature of the kneaded product became about 120 ° C.

Comparative Example 1 Comparative Example 1 was carried out in the same manner as in Example 1 except that a commercially available polypropylene wax (trade name: Viscol 550P, manufactured by Sanyo Chemical Industries, Ltd.) was used instead of the copolymer of Synthesis Example 1. Toner was obtained.

Comparative Example 2 In Example 1, a commercially available polyethylene wax (PE-13 manufactured by Hoechst) was used instead of the copolymer of Synthesis Example 1.
A comparative toner was obtained in the same manner as in Example 1 except that 0) was used.

Comparative Example 3 Comparative Example 3 was carried out in the same manner as in Example 1 except that a commercially available caster wax (hardened castor oil manufactured by Ito Oil Co., Ltd.) was used instead of the copolymer of Synthesis Example 1. A toner was obtained. Further, 5 parts by weight of the toners obtained in Examples 1 to 4 and Comparative Examples 1 to 3 and 95 parts by weight of a ferrite carrier (FL-1025 manufactured by Powder Tech) were mixed to obtain a two-component developer.

Next, the following items were tested for the two-component developer. (1) Non-offset temperature range The above two-component developer is supplied to a commercially available copying machine (trade name ED, manufactured by Toshiba Corporation).
-3810) on A4 transfer paper, 2cm long, 12c wide
A plurality of m-shaped unfixed images were prepared. Next, a paper feed speed of 190 m was applied to the hot roll type fixing device of the copying machine SF-2022 manufactured by Sharp Co. using an external fixing machine modified so that the roller surface temperature and the paper feed speed can be freely set.
m / sec, and the roller surface temperature was changed stepwise to fix the toner image on the transfer paper having the unfixed image. At this time, observation was made as to whether or not toner stains occurred in the blank portion, and a temperature range where no stains occurred was defined as a non-offset temperature range.

(2) Fixing Strength The roller surface temperature of the fixing machine is set to 170 ° C. and 190 ° C.
C., and the toner image was fixed on the transfer paper on which the unfixed image was formed. Next, the image density of the fixed image was measured with a reflection densitometer RD-914 manufactured by Macbeth Co., and then the fixed image was rubbed with an eraser (load 1 k).
g, 3 round trips), and after measuring the image density after rubbing,
The fixing strength was calculated by the following equation and used as an index of low energy fixing. Fixing strength (%) = (image density after rubbing / image density before rubbing) × 100

(3) Fluidity The toner obtained in Examples 1 to 4 and Comparative Examples 1 to 3 was used as an index indicating the fluidity of the toner.
The apparent density was measured according to No. 01.

(4) Evaluation of Storage Stability Toner 20 obtained in Examples 1-4 and Comparative Examples 1-3
g in a polyethylene bottle and 4
Stored for 8 hours. After cooling to room temperature, the toner was taken out of the bottle and the degree of aggregation was confirmed. The lump is loosely touched with a finger lightly and loose enough for practical use;
Was determined. Table 1 shows the test results of the above items.

[0031]

[Table 1] Non-offset fixing strength (%) Fluidity storage temperature range (° C) 170 ° C 190 ° C (g / cm ³ ) Stability Example 1 155 to 230 or more 60 85 0.401 ○ Example 2 150 to 230 63 86 0.392 ○ Example 3 150 to 230 or more 64 89 0.395 ○ Example 4 150 to 230 or more 66 91 0.391 ○ Comparative Example 1 165 to 230 or more 50 72 0.394 ○ Comparative Example 2 160 to 210 54 78 0.386 ○ Comparative Example 3 155 to 200 58 80 0.341 ×

[0032]

According to the present invention, there is provided an electrostatic charge developing toner having a wide non-offset temperature range, excellent fixing strength even at a low temperature, and excellent flow stability and storage stability.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-61239 (JP, A) JP-A-6-202375 (JP, A) JP-A-6-308762 (JP, A) JP-A-8-208 184986 (JP, A) JP-A-7-98511 (JP, A) JP-A-8-328296 (JP, A) JP-A-8-278663 (JP, A) JP-A-59-53593 (JP, A) JP-A-6-128524 (JP, A) JP-A-6-202267 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08 CA (STN)

Claims (3)

(57) [Claims] 1. A polyester resin having the following formula (1) (Wherein R is a hydrogen atom, a benzoic acid residue or a carbon atom number)
4 or less fatty acid residues;¹Is 11 or more carbon atoms
Represents an aliphatic group of k, m, and n indicate copolymerization ratios, and k is
0 to 0.60, m and n are both greater than 0
The value of n / (m + n) is in the range of 0.20 to 0.85
And k + m + n = 1.0. X is the average weight
Indicates the degree. )) And at least a colorant.
For developing electrostatic charge. 2. The copolymer of the formula (1) is a compound of the formula (2) (In the formula, R represents a hydrogen atom, a benzoic acid residue or a fatty acid residue having 4 or less carbon atoms. K, m, and n represent a copolymerization ratio, and k is in a range of 0 to 0.60; m and n are both greater than 0, and the value of n / (m + n) is 0.20 to 0.8.
In the range of 5, k + m + n = 1.0. X indicates the average degree of polymerization. And a polymer represented by formula (3): R ¹ —COOH (3) (wherein, R ¹ represents an aliphatic group having 11 or more carbon atoms). 2. A compound obtained by condensation with a fatty acid represented by the formula:
The toner for electrostatic charge development according to the above. 3. The toner according to claim 1, wherein the copolymer of formula (1) is contained in an amount of 1 to 60 parts by weight based on 100 parts by weight of the polyester resin.