JPH11174735A - Toner for electrostatic charge development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the toner having anti-offsetting property over a wide temp. range, low-temp. fixability, good flowability and preservability and capable of giving a uniform transferred image by incorporating a styrene-acrylic ester copolymer resin, a specified copolymer and a colorant. SOLUTION: The toner contains a styrene-acrylic ester copolymer resin, a copolymer represented by the formula and a colorant. In the formula, R is H, the residue of benzoic acid or the residue of a <=4C fatty acid, R<1> is a >=11C aliphatic group, (k), (m) and (n) show copolymn. ratio, (k) is 0-0.60, (m) is >O, (n) is >O, n/(m+n)=0.20-0.85, k+m+n=1.0 and (x) shows the average degree of polymn. The proportion of the copolymer is preferably 1-60 pts.wt. to 100 pts.wt. of the styrene-acrylic ester copolymer resin. In the case of >60 pts.wt., the dispersibility of the additive is not uniform and it is difficult to form a uniform image.

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, the present invention relates to a toner for electrostatic charge development that has a non-offset width over a wide temperature range, has low-temperature fixability, has good fluidity and storability, and can obtain a uniform transferred image.

[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 before, the power of the fixing unit can be reduced, and the size can be reduced. As a binder resin of the toner used in this method, a styrene acrylate copolymer resin (hereinafter also referred to as St / AC resin) having a wide molecular weight distribution to prevent an offset phenomenon is known. I have. However, since the offset phenomenon cannot be sufficiently prevented, it is essential to add a synthetic wax such as a low molecular weight paraffin wax or a 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 temperature range in which offset can be prevented is widened and the fixing strength tends to be good as the amount of addition increases. However, since the compatibility with the St / AC resin system is poor, these wax particles are exposed on the toner surface, and the toner fluidity is likely to be deteriorated, spent on the carrier is increased, and fusion to the developing sleeve or the photoconductor is likely to occur. In the case of vegetable wax, the offset phenomenon is prevented at a low temperature and the fixing strength tends to be improved with an increase in the amount of addition, but the offset phenomenon occurs at a high temperature due to poor releasability as compared with the synthetic wax.
At the same time, since there are many oligomer components, the preservability and fluidity of the toner deteriorate. Further, the toner having poor fluidity adheres to the inside of the pulverizing classifier at the time of pulverizing and classifying, and remarkably deteriorates productivity.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to obtain a uniform transferred image having good non-offset width over a wide temperature range, low-temperature fixability, good fluidity and preservability. It is an object of the present invention to provide a one-component developing toner or a two-component developing toner for electrostatic charge development.

[0004]

SUMMARY OF THE INVENTION Styrene acrylate
Ter copolymer resin, copolymer represented by formula (1), and
In a toner for electrostatic charge development containing at least a coloring agent
It was found that the above problem was solved. (Wherein R is hydrogen, a benzoic acid residue or a compound having 4 or less carbon atoms)
Represents a fatty acid residue;¹Represents an aliphatic group having 11 or more carbon atoms.
Show. k, m, and n indicate a copolymerization ratio, and k is 0 to 0.60.
Where m and n are both greater than 0 and n /
The value of (m + n) is in the range of 0.20 to 0.85, and k + m
+ N = 1.0. X indicates the average degree of polymerization. )

Hereinafter, the present invention will be described in detail. The copolymer represented by the formula (1) can be synthesized by condensing a polymer represented by the following formula (2) and a fatty acid represented by the formula (3). (Wherein, R represents hydrogen, a benzoic acid residue or a fatty acid residue having 4 or less carbon atoms. K, m, and n represent copolymerization ratios,
k ranges from 0 to 0.60, m and n are both greater than 0, the value of n / (m + n) ranges from 0.20 to 0.85, and k + m + n = 1.0. X indicates the average degree of polymerization. ). R ¹ —COOH (3) (wherein, R ¹ represents an aliphatic group having 11 or more carbon atoms). Alternatively, the side chain component OCOR ¹ may be introduced into the radically polymerizable monomer to carry out radical polymerization to synthesize, but the condensation method is preferable because side reactions are easily suppressed. R ¹ in the formula (3) is more preferably an aliphatic group having 11 to 40 carbon atoms. 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
The range is from 000 to 45,000. 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. When 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. When the upper limit of the above range is exceeded, the crystallinity due to intermolecular hydrogen bonding of the main chain portion of the copolymer becomes high, so that the melting temperature and the thermal decomposition temperature become close to each other, and it becomes difficult to produce the intended electrostatic charge developing toner. .

The side chain moiety 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). Also,
The temperature difference between the endothermic peak temperature in the copolymer represented by the formula (1) of the present invention and the melting start temperature in the Koka flow tester is preferably 50 ° C. or less, more preferably 40 ° C. or less, and even more preferably. 35 ° C. or less. If the temperature difference is larger than 50 ° C., the low-temperature fixability deteriorates. Further, the toner of the present invention is preferably used in an image forming apparatus in which the fixing method includes a hot roll, a heat belt, a hot plate, a flash, and a combination thereof.

The main chain portion of the copolymer represented by the formula (1), that is, the polymer represented by the formula (2) comprises 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) of 40 to 70 ° C. as measured by DSC are preferred. 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. On the other hand, if the temperature is higher than 70 ° 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 represented by the formula (2) is 2
In the case of the partially saponified polyvinyl alcohol having a saponification degree of not more than 80 mol%, more preferably not more than 70 mol% is used. Degree of saponification of partially saponified polyvinyl alcohol is 8
If it exceeds 0 mol%, the value of the melting temperature of the partially saponified polyvinyl alcohol and the value of the thermal decomposition starting temperature are close to each other, so that the obtained copolymer represented by the formula (1) tends to be non-uniform.

[0008] 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 acid represented by the formula (3) used in the present invention is a saturated or unsaturated fatty acid having 12 or more carbon atoms.
Specifically, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, 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., and natural mixtures thereof such as tallow fatty acid, tallow hardened fatty acid, palm oil fatty acid, palm oil hardened fatty acid, sugar fatty acid, vegetable oil fatty acid, fish oil hardened fatty acid, soy hardened fatty acid, Examples thereof include esterified products and derivatives such as coal-derived montanic acid. These can be used alone or in combination depending on the physical properties. In addition, long chain synthetic fatty acids are also available from Petrolite under the trade name Unisid with a molecular weight of 80.
It is marketed to about 0 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 saturated and unsaturated fatty acids having a melting point of 6
Those having a temperature of 5 to 120 ° C are particularly preferred. The copolymer represented by the formula (1) can be produced by either a melting method or a solution method.
Further, it can be obtained by subjecting a polymer represented by the formula (2) and a fatty acid represented by the formula (3) to a condensation reaction at 150 to 290 ° C. in a nitrogen atmosphere.

In producing 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 hydrogen,
Known esterification catalysts, 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. Further, when the reactive group is a lower ester represented 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, 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 comprises at least a St / AC resin, a copolymer represented by the formula (1) and a colorant, and optionally further contains and disperses additives as necessary. Having an average particle size of 5
２０20 μm. An additive consisting 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 proportion of the copolymer of the formula (1) contained in the toner is preferably 1 to 60 parts by weight based on 100 parts by weight of the St / Ac resin. If the amount is less than 1% by weight, not only no improvement in low-temperature fixability 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 it exceeds 60 parts by weight, St / A
The dispersibility of the C-based resin and other additives such as a colorant and a charge control agent in the copolymer represented by the formula (1) tends to be non-uniform,
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 desirable ratio 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.

[0013] Other additives that are optionally added 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 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; 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 alloy. Magnetic powder having an average particle diameter of 1 μm or less is preferably used. You. 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.
Inorganic fine particles, resin fine particles and magnetic powder having a diameter of not more than μm are preferably used. As the inorganic fine particles such as silica, alumina and 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 action, and the amount of these additives is 0.01 to 100 parts by weight of the toner.
３3 parts by weight.

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 composed of resin particles containing iron powder, ferrite, granulated magnetite, 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 toner for electrostatic charge development of the present invention is preferably used in a heat fixing system using 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.

The endothermic onset temperature, endothermic peak temperature, and glass transition point (Tg) of the present invention were measured by using DSC: DSC-120 manufactured by Seiko Denshi Kogyo Co., Ltd. The temperature was raised and quenched at 10 ° C./min twice, and the second time Was determined from an endothermic curve at the time of temperature rise. 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 Shimadzu's CF-type flow tester: CF
Using T-500, the plunger descent temperature under the following measurement conditions was taken as the melting start temperature, and the midpoint from the descent start temperature to the descent end temperature 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 ratio: 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 was 11.2 ° C., the number average molecular weight Mn was 34,300, and the grafting ratio was 40 mol%.

Synthesis Example 2 [Synthesis Example Using Polyethylene Vinyl Alcohol and Behenic Acid (Grafting Ratio: 60 mol%)] The amounts of polyethylene vinyl alcohol, behenic acid, and calcium acetate were changed to polyethylene vinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd.). Name: Soarnol E380
3) The copolymer of the present invention was obtained in the same manner as in Synthesis Example 1, except that 18.98 g, 63.34 g of behenic acid and 1.26 g of calcium acetate were used. The endothermic onset temperature of the obtained copolymer is 53.1 ° C, the endothermic peak temperature is 60.6 ° C,
Melting start temperature is 63.0 ° C., and flow softening point is 79.44.
° C, the difference between the melting onset temperature and the endothermic peak temperature is 2.4 ° C,
Mn was 44,200, and the grafting ratio was 60 mol%.

Synthesis Example 3 [Polyethylene vinyl alcohol-
Example of synthesis with behenic acid and behenic acid (graft rate: 40 mol%)] Using 24.0 g of the low-molecular-weight ethylene-vinyl alcohol copolymer obtained below and 53.55 behenic acid
g, and the reaction was carried out in the same manner as in Synthesis Example 1 except that 1.61 g of calcium acetate was used as a catalyst, while melting under a nitrogen stream 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 is 53.7 ° C., and the endothermic peak temperature is 60.
1 ° C, flow start temperature by flow tester is 65.4
° C and the flow softening point was 79.2 ° C. Mn is 210
It was 0.

[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 an ordinary method were charged, and nitrogen gas was bubbled into this solution from a nitrogen introduction 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 Synthesis Examples 1 to 3, the toner of the present invention was prepared according to the following composition and procedure.

Example 1 100 parts by weight of St / AC resin (trade name: CPR-100 manufactured by Mitsui Toatsu Chemicals) 5 parts by weight of the copolymer obtained in Synthesis Example 1 carbon black (trade name: MA-100 manufactured by Mitsubishi Chemical Corporation) 6 parts by weight Charge control agent (trade name: TRH, manufactured by Hodogaya Chemical Industry Co., Ltd.) 1 part by weight Henschel mixer (manufactured by Mitsui Miike Kogyo Co., Ltd.)
And mixed. The mixture is kneaded with a twin-screw kneader to a temperature of about 1
After melt-kneading at 45 ° C., the resultant was subjected to jet pulverization and airflow classification 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 2 and 3 was used instead of the copolymer obtained in Synthesis Example 1. The toners of Examples 2 to 3 were obtained.

Example 4 A toner was obtained in the same manner as in Example 1 except that the copolymer of Synthesis Example 1 was changed to 20 parts by weight and kneaded so that the temperature of the kneaded product was about 120 ° C.

Comparative Example 1 Instead of the copolymer of Synthesis Example 1, an equal amount of a commercially available polypropylene wax (trade name: Viscol 55 manufactured by Sanyo Chemical Industries, Ltd.)
A comparative toner was obtained in the same manner as in Example 1, except that OH was used.

Comparative Example 2 A comparative toner was obtained in the same manner as in Example 1 except that the same amount of a commercially available polyethylene wax (PE-130 manufactured by Hoechst) was used in place of the copolymer of Synthesis Example 1. Was.

Comparative Example 3 A comparative toner was prepared in the same manner as in Example 1 except that the same amount of commercially available caster wax (hardened castor oil manufactured by Ito Oil Co., Ltd.) was used instead of the copolymer of Synthesis Example 1. 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 on the transfer paper on which the unfixed image was formed was fixed. Next, the image density of the fixed image was measured with a Macbeth reflection densitometer RD-914.
Rubbing of fixed image with eraser (load 1 kg, 3
(Reciprocation), and the image density after the rubbing was measured, and then the fixing strength was calculated by the following formula to be 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.

[0033]

[Table 1] Non-offset fixing strength (%) Fluidity storage temperature range (° C) 170 ° C 190 ° C (g / cm ³ ) Stability Example 1 150 to 220 or more 80 95 0.367 ○ Example 2 150 to 220 82 96 0.372 ○ Example 3 150 to 220 or more 81 97 0.369 ○ Example 4 150 to 220 or more 90 100 0.361 ○ Comparative Example 1 165 to 220 or more 60 81 0.352 ○ Comparative Example 2 160 to 210 66 88 0.341 ○ Comparative Example 3 155 to 205 72 90 0.312 ×

[0034]

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

Claims (3)

[Claims] 1. A styrene acrylate copolymer tree
Fat, a copolymer represented by the following formula (1), and a coloring agent
A toner for electrostatic charge development containing at least (In the formula, R is hydrogen, a benzoic acid residue or a carbon atom number of 4 or less.
The lower fatty acid residue¹Is a fat with 11 or more carbon atoms
Shows an aliphatic group. k, m, and n indicate the copolymerization ratio, and k is 0 to
0.60 where 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 degree of polymerization
Is shown. ). 2. The copolymer of the formula (1) is a compound of the formula (2) (Wherein, R represents hydrogen, a benzoic acid residue or a fatty acid residue having 4 or less carbon atoms. K, m, and n represent copolymerization ratios,
k ranges from 0 to 0.60, m and n are both greater than 0, the value of n / (m + n) ranges from 0.20 to 0.85, and 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 developing an electrostatic image according to the above. 3. The copolymer of formula (1) is used in an amount of 1 to 60 parts by weight per 100 parts by weight of the styrene acrylate copolymer resin.
The toner for developing an electrostatic image according to claim 1, which is contained in parts by weight.