JPH0822145A - Electrostatic charge image developing toner and image forming method - Google Patents

Abstract

PURPOSE:To provide such an electrostatic charge image developing toner that can be fixed at a low temp. in a contact heating and fixing method, has a wide temp. range for fixing, gives excellent picture qualities such as high copy density with high initial picture quality and picture quality after many times of copying and no deposition of the toner on the background, and does not cause thermal aggregation during storage, and to provide an image forming method using that. CONSTITUTION:This electrostatic charge image developing toner contains a binder resin and a coloring agent. The binder resin contains a vinyl polymer, polyester resin and the reaction product of vinyl polymer and polyester resin. When the toner is a black toner, the coloring agent contains carbon black having at least one max. in each range of <=0.03mum particle size and 0.4 to 0.7mum in the distribution of particle size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic charge image for developing an electrostatic charge image in an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like, and an image forming method using the toner.

[0002]

2. Description of the Related Art In electrophotography and the like, when an electrostatic latent image is visualized by using a toner, a two-component developing system composed of a toner and a carrier, represented by a magnetic brush method, and a magnetic toner containing a magnetic material. Is known. Further, as a method of fixing the toner through development and transfer, a contact heating fixing method using a heat roll is generally used. Toners with lower temperature fixability are required to save energy and speed up, but such a toner is liable to cause offset to the heat roll in the contact heating fixing method, and low temperature fixability and offset resistance Balancing gender is an issue. Conventionally, for the purpose of improving the fixability, it is proposed to use a binder resin having a maximum value of particle size distribution in each of a low molecular weight region and a high molecular weight region (for example, JP-A-56-16144), Proposals have been made to use crystalline and sharp-melting polyester resins, but they do not satisfy the contradictory requirements of thermal agglomeration during storage and grindability during toner production, and are still satisfactory. It shouldn't be.

On the other hand, regarding the colorant, carbon black is used as a colorant for a black toner, but its dispersibility greatly affects the chargeability of the toner, so that the dispersed particle size of the carbon black is made uniform. (JP-A-3-18
862), and defining the particle size range of carbon black aggregates (see JP-A-2-103561) has been proposed. However, it is not possible to achieve both chargeability and charge exchangeability simply by making the dispersed particle size and the aggregate particle size of carbon black uniform. Especially, when the number of copies becomes large, a predetermined copy density is obtained. However, there is a problem in that the toner cannot be adhered or the toner adheres to the background portion.

[0004]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems in the prior art. An object of the present invention is that in a contact heating fixing system, it has an extremely wide feasible temperature range, that is, there is a wide range between the minimum fixing temperature for obtaining a satisfactory fixing degree and the maximum temperature at which hot offset does not occur, Moreover, it is to provide a toner for developing an electrostatic charge image that does not cause thermal aggregation during storage. Another object of the present invention is to provide a toner for developing an electrostatic charge image having good pulverizability. Another object of the present invention is to provide an electrostatic charge image developing toner having good storability that does not cause transfer of the toner to the vinyl chloride sheet when the toner fixed image and the vinyl chloride sheet are in close contact with each other and stored. To do. Further, an object of the present invention is to ensure a desired charge amount, have excellent charge exchange properties, have a sharp charge distribution even after adding toner, and have very little toner adhesion to the background portion, and durability. An object of the present invention is to provide a toner for developing an electrostatic charge image, which contains carbon black having excellent properties and stability of image quality.

[0005]

The toner for developing an electrostatic charge image of the present invention contains a binder resin and a colorant, and the binder resin is a vinyl polymer, a polyester resin,
And a chemical reaction product of a vinyl polymer and a polyester resin. In one embodiment of the electrostatic image developing toner of the present invention, the colorant has a particle size distribution of 0.
It is characterized by containing carbon black having at least one local maximum in the range of not more than 03 μm and in the range of 0.4 to 0.7 μm. In the image forming method of the present invention, a step of forming a latent image on a latent image carrier, a step of developing the latent image with a developer, a step of transferring a toner image onto a transfer body and thermally fixing the toner image. And is characterized in that the above-mentioned toner for developing an electrostatic charge image is used as a developer.

The present invention will be described in detail below.
In the present invention, the vinyl polymer, which is one of the components constituting the binder resin, is a homopolymer of vinyl monomers or a copolymer of two or more vinyl monomers. Typical vinyl monomers are styrene and p. -Chlorostyrene, vinylnaphthalene, for example, ethylene, propylene, butylene, ethylenically unsaturated monoolefins such as isobutylene, for example, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, Vinyl esters such as vinyl butyrate, vinyl formate, vinyl stearate, vinyl caproate, for example,
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, dodecyl acrylate,
Ethylenic monocarboxylic acids such as n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl-α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and their esters, such as acrylonitrile, Ethylenic monocarboxylic acid substitution products such as methacrylonitrile and acrylamide, for example, dimethyl maleate, diethyl maleate, dibutyl maleate and other ethylenic dicarboxylic acids and esters thereof, for example, vinyl methyl ketone, vinyl hexyl ketone, methyl Vinyl ketones such as isopropenyl ketone, for example, vinyl methyl ether, vinyl isobutyl ether, vinyl ethers such as vinyl ethyl ether, for example, vinylidene chloride,
Examples thereof include vinylidene halides such as vinylidene chlorfluoride, and N-vinyl heterocyclic compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone. The vinyl polymer can be synthesized using these monomers by a known method such as a solution polymerization method, a bulk polymerization method or a suspension polymerization method. The average molecular weight of the vinyl polymer is Mw = 3
50,000 to 800,000, Mn = 1,000 to 10
Those in the range of 10,000 can be preferably used.

Examples of the polyester resin include those obtained from a polyvalent hydroxy compound and a polyvalent carboxylic acid or a reactive acid derivative such as a lower alkyl ester thereof, an acid anhydride or an acid halide. As the polyhydric hydroxy compound, ethylene glycol, propylene glycol,
1,4-butanediol, 2,3-butanediol,
Polyethylene glycol such as 1,5-pentanediol, 1,6-hexanediol, neopentylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol and triethylene glycol, polypropylene glycol such as dipropylene glycol and tripropylene glycol, bisphenol A and its derivatives,
In addition to the alkylene oxide adducts, divalent hydroxy compounds such as hydrogenated bisphenol A, glycerin,
A trivalent or higher hydroxy compound such as sorbitol, 1,4-sorbitan, and trimethylolpropane can be used. Examples of the polyvalent carboxylic acid include malonic acid, succinic acid, glutaric acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid, n-octylsuccinic acid, 1, 3-dicarboxy-2
-Methyl-2-carboxymethylpropane, tetra (carboxymethyl) methane, maleic acid, fumaric acid, dodecenylsuccinic acid, 1,2,4-cyclohexanetricarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid Acid, 1,2,4-naphthalene tricarboxylic acid can be used. The polyester resin used in the present invention has a weight average molecular weight Mw of 7,000.
0-50,000, number average molecular weight Mn is 2,000-
In the range of 10,000, the Tg is preferably in the range of 50 to 70 ° C. In addition, polyester resin is 3 of all binder resins.
It is preferably in the range of 50% by weight.

The chemical reaction product of the vinyl polymer and the polyester resin can be obtained by various methods. For example, a vinyl polymer containing glycidyl methacrylate as a part of the monomer and the polyester resin described above. Can be synthesized by heating in solution. The chemical reaction product of the vinyl polymer and the polyester resin is Mw: 7,000 to 1
0,000, Mn: 2,000 to 30,000, T
The g is preferably in the range of 50 to 70 ° C. Also,
The chemical reaction product of the vinyl polymer and the polyester resin is preferably in the range of 2 to 20% by weight based on the total binder resin. If the amount is less than 2% by weight in the total binder resin, the compatibility between the vinyl polymer and the polyester resin is poor and the pulverizability is good, but the fixability is extremely poor. On the other hand, if it exceeds 20% by weight, it becomes difficult to achieve both crushability and fixability. The preferred blending ratio of the binder resin in the present invention is polyester resin 5
It is preferable that the content is ˜30 wt%, the chemical reaction product of vinyl polymer and polyester resin is 5 to 15 wt%, and the balance is vinyl resin.

As the colorant in the present invention, any known colorant can be used. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal,
C. I. Pigment Red 48: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 1
22, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15: 1, C.I.
I. Pigment Blue 15: 3 can be mentioned as a typical example. When the toner of the present invention is used as a magnetic toner, as the magnetic powder, known magnetic materials such as metals such as iron, cobalt, nickel and alloys thereof, Fe ₃ O ₄ , γ-Fe ₂ O _{3 can be used.} Metal oxides such as cobalt-added iron oxide, MnZn ferrite, magnetite, hematite, and the like can be used, and those obtained by treating these with a silane coupling agent, a titanium coupling agent, or the like can also be used. Generally, these colorants may be contained in the toner in the range of 2 to 30% by weight.

In the present invention, when carbon black is used as the colorant, in the toner, the peak of the particle size distribution of the primary particles is 0.03 μm or less, and the peak of the aggregate is 0.4 to 0. It is preferable that the particles are dispersed so as to be in the range of 7 μm. In that case, it is possible to achieve both the charge amount and the charge exchange property, the image quality is excellent, the toner is hardly adhered to the background portion, and the black is excellent in durability. Toner is obtained. As the carbon black used for dispersing in the present invention as described above, one having a pH of 3 or less, a primary particle diameter of 20 nm or less, and a dibutyl phthalate oil absorption of 80 cc / 100 g or more of carbon black is suitable. ing. The pH of carbon black exceeds 3,
If the primary particle size exceeds 20 nm, a sufficient charge amount cannot be obtained, and the dibutyl phthalate oil absorption is 80 cc /
When the amount of carbon black is less than 100 g, aggregates are not preferably formed, which causes a loss of charge exchange properties. The above-mentioned carbon black is preferably added to the toner particles in an amount of 5 to 15% by weight, particularly 7 to 12% by weight. 5% by weight
If it is less than the above range, the desired image density cannot be obtained, and if it exceeds 15% by weight, the conductivity becomes too large and the desired charge amount cannot be obtained.

The dispersed particle diameter and the primary particle diameter of carbon black in the resin in the present invention were measured by taking a photograph magnified 4500 to 30000 times with a transmission electron microscope. Also, dibutyl phthalate oil absorption is AST
EM-D2414, pH is measured by ASTEM-D1512.

In the present invention, various substances can be added for the purpose of charge control, electric resistance control and the like. For example, fluorine-based surfactants, salicylic acid, chromium-based dyes such as chromium complexes, maleic acid, charge control resins such as copolymers containing amino group-containing vinyl monomers as monomer components, and quaternary ammonium salts. , And azine dyes such as nigrosine can be added. Furthermore, a releasing agent may be added in order to make offset resistance more complete, and polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene, paraffin wax, candelilla wax, carnauba wax, montan wax, etc. Natural wax and its derivatives can be used.

In the present invention, the inorganic compound fine particles externally added to the toner particles include SiO ₂ , TiO ₂ , and Al.
₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂
O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, Z
rO ₂ , CaO.SiO ₂ , K ₂ O. (TiO ₂ ) _n ,
Al ₂ O ₃ .2SiO ₂ , CaCO ₃ , MgCO ₃ , B
Examples thereof include aSO ₄ , MgSO _4, etc., and those whose surface is treated with a resin or various coupling agents.

The toner for developing an electrostatic image of the present invention can be used in any method for visualizing an electrostatic latent image, such as a step of forming a latent image on a latent image carrier, It can be advantageously used in an image forming method having a step of developing a latent image with a developer and a step of transferring a toner image onto a transfer body and thermally fixing it.

[0015]

It is presumed that the effects of the present invention will be exhibited for the following reasons. By using the reaction product of the vinyl polymer and the polyester resin as a part of the binder resin, the compatibility of the vinyl polymer and the polyester resin is extremely improved, and the polyester resin is contained in the vinyl polymer. , Microdisperse. Since the vinyl polymer forms the continuous phase, the pulverizability is good, and the polyester resin, which is a low melt viscosity component, exhibits low-temperature fixability during fixing. Further, since the compatibility between the vinyl polymer and the polyester resin is good, the elasticity of the entire resin is not impaired even at a high temperature during fixing, and offset does not occur. Further, it is presumed that the image strength is maintained even after fixing and the image is not easily destroyed by ironing, rubbing, bending and the like. Regarding the dispersion of carbon black, it is considered that high dispersion is achieved due to the high affinity between carbon black and the polyester resin. Also,
Carbon black of 0.03 μm or less has an effect on chargeability / maintainability, while the presence of aggregates having a peak in the particle size distribution of 0.4 to 0.7 μm improves the charge exchangeability. Be done.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is in no way limited by these examples. In the following description, all “parts” represent “parts by weight”. Production Example 1 (Vinyl Polymer) First, as a polymerization initiator, 20 g of azobisisobutyronitrile, 450 g and 50 g of styrene and n-butyl acrylate, respectively, and a toluene solvent 300
It was charged in 100 ml of water, and the low molecular weight components were polymerized at 110 ° C. for 6 hours. After completion of the reaction, the solvent was once distilled off, and 1.2 g of azobisisobutyronitrile as a polymerization initiator and 182 g of styrene were added. -Adding 32 g of butyl acrylate and 1 g of divinylbenzene, polymerization of the high molecular weight component was carried out at 130 ° C for 8 hours by bulk polymerization to obtain a weight average molecular weight M
w = about 180,000, number average molecular weight Mn = about 3,70
A vinyl polymer having 0 and Tg = 61 ° C. was obtained.

Production Example 2 (Polyester Resin A) Bisphenol A-ethylene oxide 2 adduct 30 mol Bisphenol A-propylene oxide 2 adduct 20 mol Terephthalic acid 30 mol Fumaric acid 20 mol Stainless steel stirrer, glass nitrogen gas, The flask was placed in a four-neck round bottom flask equipped with an introduction tube and a flow-down condenser, and the temperature was raised by a mantle heater while introducing nitrogen gas. Then, the temperature of the reaction product was kept at 200 ° C., and the reaction was carried out for 6 hours while distilling off the produced water. The obtained polyester resin has a weight average molecular weight Mw of about 1
4,000, number average molecular weight Mn = about 4,000, Tg =
It was 61 ° C.

Production Example 3 (Polyester Resin B) The weight average molecular weight Mw is about 9,000 and the number average molecular weight Mn is about 3,500 in the same manner as in Production Example 2 except that the molar ratios of the charged monomers are as follows. , Tg = 65 ° C. was obtained. Bisphenol A-ethylene oxide 2 adduct 10 mol Bisphenol A-propylene oxide 2 adduct 15 mol Neopentyl glycol 24 mol Terephthalic acid 22 mol Isophthalic acid 20 mol

Production Example 4 (Polyester resin C) Bisphenol A-ethylene oxide 2 adduct 21 mol Bisphenol A-propylene oxide 2 adduct 21 mol Succinic acid derivative 7 mol Terephthalic acid 4 mol Trimellitic acid 25 mol Other than using the above components In the same manner as in Production Example 2, a polyester resin containing 20% of gel content was obtained. (Tg = 63
℃)

Production Example 5 (Chemical reaction product of vinyl polymer and polyester resin) Weight average molecular weight M consisting of 75 parts of styrene, 10 parts of n-butyl acrylate and 15 parts of glycidyl methacrylate.
60 parts of a vinyl-based polymer having w = 15,000 and a number average molecular weight Mn = 6,000 and 40 parts of the polyester resin obtained in Production Example 2 were added with 1 part of dibutyltin oxide in a toluene solvent and heated under reflux. Reaction for time, Mw = 2
A reaction product with 5,000 and Mn = 5,500 was obtained.

Production Example of Binder Resin The vinyl polymer, the polyester resin, and the chemical reaction product of the vinyl polymer and the polyester resin were mixed at a ratio of 1 shown in Table 1 at 80 ° C. in a toluene solvent. After mixing for a period of time, the solvent was distilled off and dried to obtain a binder resin A for toner.

Toner Production Example 1 (Examples 1 to 3 and Comparative Examples 1 to 3) -Binder Resin A 100 parts-Carbon Black 8 parts (BP-1300, manufactured by Cabot Corporation, pH 2.5, average primary particles) Diameter 13 nm, dibutyl phthalate oil absorption 95 to 100 cc / 100 g carbon black) -Low molecular weight polypropylene (Viscor 660P, Sanyo Kasei Co., Ltd.) 6 parts The above components were melted and kneaded by a Banbury mixer. After rolling and cooling, coarse crushing was performed with a hammer mill, and then fine crushing was performed with a jet mill to obtain a volume average particle diameter d ₅₀ of 10 μm.
Toner particles were obtained. Further classification, d ₅₀ is 10.5
μm toner particles were obtained. To 100 parts of this toner particle, 0.8 part of hydrophobic silica R-972 was added and dispersed and mixed using a Henschel mixer to prepare a toner having silica fine particles attached to the surface.

Preparation of Developer A carrier of the developer for FX-5039 was used as a carrier, and the above-prepared toner was mixed with a V blender to a toner concentration of 4 to 6% to obtain a developer. The developer was evaluated by the following evaluation methods. The results are shown in Tables 1 and 2.

(1) Minimum fixing temperature evaluation method (a) Electrophotographic copying machine Able 3300 (manufactured by Fuji Xerox Co., Ltd.) using a color developing device, the image density after fixing is constant (optical density is about 1.3). (4) Adjust the developing bias so that the image becomes, and collect an unfixed image on plain paper. (b) The plain paper from which the unfixed image has been collected is passed through a fixing device (roll speed: 250 mm / sec, nip pressure: 2.0 kg / cm ² ) with a variable heat roll temperature. (c) The fixed image thus fixed is rubbed 10 times with a rubbing tester with a load of 750 g. (d) Image density ratio before and after the rubbing test: The minimum fixing temperature is the heat roll temperature at which the value of (image density after test / initial image density) × 100% exceeds 70%. In addition, ◯ means excellent, and x means that there is a problem in practical use. (2) Hot offset occurrence temperature evaluation method (a) Unfixed images are sampled on two plain papers in the same manner as in (1) (a) above. (b) In the same manner as in (1) and (b) above, two plain sheets of paper on which an unfixed image has been collected are successively passed through the fixing device. (c) The hot offset temperature is the hot roll temperature at which it is possible to visually confirm that the first fixed image is offset on the second plain paper. In addition, ○ is excellent, ×
Means that there is a problem in practice. (3) Thermal cohesiveness evaluation method (a) Approximately 30 g of toner was placed in an aluminum container, and 5
It is left for 24 hours in an environment of 0 ° C. and 50% RH. (b) After allowing to cool to room temperature, sieving with a 106 μm sieve,
The amount remaining on the sieve is determined, and the value of (remaining amount on the sieve / amount charged) × 100% represents the thermal cohesiveness. In addition, ◯ means excellent, Δ means that some blocking was observed, and × means blocking occurred. (4) Evaluation Method of Grindability The jet feed grinder evaluated the feed rate of the toner when d ₅₀ = 10 μm of the toner was obtained with the same crushing pressure and the same air flow. In that case, the feed rate when the binder resin of Production Example 4 was used was 1.0, and the feed rate was expressed. In addition, ◯ means excellent, Δ means normal, and × means inferior. (5) Continuous Copy Test The above developer was applied to a copying machine (FX5031, manufactured by Fuji Xerox Co., Ltd.) to perform a continuous copy test on 10,000 sheets continuously to evaluate the copy density and toner adhesion to the background portion. The copy density was measured with a Macbeth densitometer, and the toner adhesion to the background portion was determined by comparison with a 5-step sample from G1 (good) to G5 (bad).

[0025]

[Table 1]

[0026]

[Table 2] As shown in Tables 1 and 2, the toner of the present invention has a wide fixing temperature range based on the characteristics of the binder resin, has no thermal agglomeration, has high pulverizability, and has carbon having the above particle size distribution. By using black, the initial image quality and the image quality after copying 10,000 sheets are excellent.

[0027]

EFFECT OF THE INVENTION The toner for developing an electrostatic image of the present invention has the above-mentioned constitution. Therefore, in the contact heat fixing method, the toner is fixed at a low temperature and has an extremely wide fixable temperature range. At the same time, it shows high productivity due to its good pulverizability, and during transportation and storage after production,
It has an excellent effect of not causing aggregation. Further, the toner does not migrate to the vinyl chloride sheet, and the storage stability is excellent. Further, in the present invention, the carbon black-containing black toner has both excellent initial image quality, high image quality after a large number of copies, and excellent image quality without toner adhesion on the background portion. Further, according to the image forming method of the present invention using this black toner, it is possible to secure a desired charge amount, has an excellent charge exchange property, has a sharp charge distribution even after the addition of the toner, and has a background portion. It is possible to form an image having very little toner adhesion to the toner, excellent durability, and stable image quality.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G03G 15/08 507 L G03G 9/08 325 331 361 (72) Inventor Yasunari Kishimoto Takematsu, Minamiashigara City, Kanagawa Prefecture 1600 Fuji Xerox Co., Ltd.

Claims (3)

[Claims] 1. A toner for developing an electrostatic charge image containing a binder resin and a colorant, wherein the binder resin is a vinyl polymer, a polyester resin, or a chemical reaction product of the vinyl polymer and a polyester resin. A toner for developing an electrostatic charge image, which comprises: 2. The colorant in the resin has a particle size distribution of 0.03 μm.
3. At least one local maximum value in each of m or less and 0.4 to 0.7 μm.
The toner for developing an electrostatic image as described in 1. 3. An image forming method comprising a step of forming a latent image on a latent image carrier, a step of developing the latent image with a developer, and a step of transferring a toner image onto a transfer body and thermally fixing the toner image. An electrostatic latent image developing toner according to claim 1 is used as a developer.