JPH08146660A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE: To provide a toner excellent in fixing property, anti-offset property and anti-blocking property. CONSTITUTION: This toner contains a binder resin and a colorant. The binder resin consists of a low molecular weight component in which weight average molecular weight is >=50,000, glass transition point is 50-60 deg.C and a molecular weight peak is 3×10<3> -1×10<5> by gel permeation chromatography and a high molecular weight component in which a molecular weight peak is 1×10<5> -1×10<7> , and the glass transition point of a resin whose weight average molecular weight is 2.0×10<5> and having the same monomer composition as the low molecular weight component is lower than that of a resin whose weight average molecular weight is 2.0×10<5> and having the same monomer composition as the high molecular weight component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge developing toner. More specifically, it relates to a toner for developing an electrostatic charge image, which is excellent in fixability (low temperature fixability, fix strength, offset resistance), blocking resistance and aging resistance using a resin having a specific molecular weight distribution and a monomer composition as a binder. .

[0002]

2. Description of the Related Art An electrostatic image developing toner does not cause a so-called offset phenomenon in which a toner is rapidly fixed, the toner is transferred to the surface of a fixing roller, and a transfer material that subsequently passes through a fixing step is contaminated by the toner on the roller. It is necessary. Further, the toner should not block during storage or transportation. In general, the blocked toner has markedly deteriorated fluidity and chargeability, and can no longer function as a developer. Moreover,
The toner needs to show good fluidity without generating fine powder due to mechanical impact due to agitation in the developing device, and also shows good fluidity without aggregation of the toner itself. It is necessary that the molten toner melts and that the molten toner exhibits a cohesive property when melted. Therefore, the binder resin, which is the main component of the toner, is required to have delicate hardness and heat melting characteristics, and it is extremely difficult to design a binder resin that satisfies all of these performances.
In particular, since low-temperature fixability / fixing strength and offset resistance / blocking resistance are contradictory performances, it is extremely difficult to achieve both performances at the same time.

Many proposals have hitherto been made regarding the molecular weight and molecular weight distribution of polymers used as binder resins. For example, the number average molecular weight is 1000-4
A toner containing 50 to 95% by weight of a low-melting high-fluidity resin having a low temperature of 000 has been proposed (Japanese Patent Publication No. 59-1073).
No. 60) still has problems in offset resistance and blocking resistance. In addition, Japanese Examined Japanese Patent Publication 63-32180
In the publication, the molecular weight is 10 ³ to 8 × 10 ⁴ and 1
It has been proposed to use a styrene copolymer binder resin having at least one local maximum in each region from 0 ^{5 to} 2 × 10 ⁶ .

[0004]

However, the toner by the conventional method has not yet been able to obtain satisfactory results in terms of fixing property to a transfer material, particularly both fixing strength and blocking resistance / aging resistance. That is, according to this method, the content of the low molecular weight component must be increased in order to improve the low-temperature fixing property and fixing strength, which causes problems in blocking resistance and aging resistance. On the contrary, in order to improve blocking resistance and aging resistance, it is necessary to increase the content of the high molecular weight component,
In this case, there are problems in low temperature fixability and fix strength.

[0005]

The present inventors have solved the above problems and provided a toner having excellent fixability (low temperature fixability, fix strength, offset resistance), blocking resistance and aging resistance. As a result of intensive studies to achieve the above, a toner satisfying the above-mentioned performance has been completed by using a specific binder resin. That is, the gist of the present invention is that the weight average molecular weight (hereinafter abbreviated as “Mw”) is 50,000 or more, the glass transition temperature (hereinafter abbreviated as “Tg”) is 50 to 60 ° C., and the molecular weight in a gel filtration chromatogram. 3 x 10
^It consists of a low molecular weight component having a peak at ³ to 1 × 10 ⁵ and a high molecular weight component having a peak at a molecular weight of 1 × 10 ⁵ to 1 × 10 ⁷ , and has a weight average molecular weight of 2.0 × 10 ⁵ and is the same as the low molecular weight component. The resin having a monomer composition contains a binder resin and a colorant having a glass transition temperature lower than the glass transition temperature of a resin having a weight average molecular weight of 2.0 × 10 ⁵ and the same monomer composition as the high molecular weight component. In the toner for developing an electrostatic image,

The contents of the present invention will be described in detail below. The binder resin of the present invention has Mw of 50,000 or more. When it is less than 50,000, even if the other conditions are satisfied, the hot offset generation temperature becomes low and it is difficult to use. It is preferably 120,000 or more, and particularly preferably
It is 150,000 or more and 700,000 or less.

Furthermore, the binder resin of the present invention has a Tg of 50.
It is essential that the temperature is in the range of ℃ to 65 ℃. Tg is 50
If the temperature is less than ℃, the blocking resistance is poor and the Tg is 65.
If the temperature is higher than 0 ° C, the lower limit fixing temperature cannot be lowered. Furthermore, the binder resin of the present invention has one or more peaks between the molecular weight of 3 × 10 ³ to 1 × 10 ⁵ and the molecular weight of 1 × 10 ⁵ to 1 × 10 ^{7 in} the gel filtration chromatogram. If the molecular weight distribution has only a single peak,
A binder resin having a well-balanced lower limit fixing temperature, hot offset temperature, and blocking resistance cannot be obtained. The binder resin of the present invention may have a molecular weight peak other than the above range, and the low molecular weight component and the high molecular weight component may have different types of resins. The binder resin is 4 × 10 ^{3 to} 5 × 10 ⁴ and 4 × 10 ^{5 to} 5 ×
It is desirable to have one or more peaks each between 10 ⁶ .

According to the present invention, 3 × 10 ³ to 1 × 10 ⁵
The monomer composition of the resin component (low molecular weight component) having a peak at is defined as a monomer composition that lowers the Tg (Tg ') of the resin when a resin having an Mw of 2.0 x 10 ⁵ is made with this monomer composition. By doing, 3 × 10 ³ to 1 × 10
Within the range of ^5, the fixability will not be impaired even if the peak is set on the high molecular weight side. Further, by setting the amount to the high molecular weight side, the amount of toner adhered to the carrier (spent toner) can be suppressed to a low level, and the aging property of the developer is improved. In addition to this, 1 × 10 ⁵ to 1 × 10
The monomer composition of the resin component (high molecular weight component) having a peak at ⁷ is set so that the Tg when a resin having an Mw of 2.0 × 10 ⁵ is made from this monomer composition is higher than the above Tg ′. As a result, a resin having excellent strength can be obtained. That is, by using the binder resin, a toner excellent in fixing property, blocking resistance and aging resistance can be obtained.

In the present invention, the binder resin is preferably a styrene resin. The styrene-based resin in the present invention means a (co) polymer of at least styrene or styrene having a substituent and, if necessary, other vinyl monomer. The monomer used in the synthesis of the styrene resin of the present invention is not particularly limited as long as it satisfies the constituent requirements of the present invention. For example, as the styrene having a substituent, α-methylstyrene, p-chlorostyrene, o- Chlorostyrene, p-methylstyrene, o-methylstyrene and the like can be mentioned. As a monomer to be copolymerized with styrene or a styrene having a substituent as required, (meth) acrylic acid esters such as alkyl acrylate and methacrylic acid alkyl ester; acrylonitrile; maleic acid such as maleic acid and maleic acid ester. Acids; vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl benzoate; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl propyl ether. Vinyl group-containing monomers such as

The styrene resin used in the present invention is a known method, for example, suspension polymerization method, emulsion polymerization method, solution polymerization method,
It is synthesized by a bulk polymerization method or the like. Further, in order to control the molecular weight, known chain transfer agents, for example, mercaptans such as lauryl mercaptan, phenyl mercaptan, butyl mercaptan, dodecyl mercaptan, carbon tetrachloride, carbon halides such as carbon tetrabromide are used. be able to.

The binder resin of the present invention may have different monomer compositions for the low molecular weight component and the high molecular weight component. In this case, the binder resin can be made at once by adding a monomer during the synthesis, or different. It can also be made by separately synthesizing two or more kinds of resins having different monomer compositions and different molecular weight peaks and mixing them by a known method. Generally, it can be produced by a method known as a two-step polymerization method, melt mixing, and melt mixing.

The binder resin of the present invention described above may be mixed with a small amount of another known resin. For example, when the binder resin is a styrene resin, a small amount of polyester resin, epoxy resin, silicone resin, polyamide resin, polyurethane resin, (meth) acrylic resin or the like may be mixed, but the amount thereof is 30% of the total amount of the resin. weight%
The following are preferred. In the present invention, a usual known method is used to measure the molecular weight distribution of the binder resin. For example, an appropriate method in ordinary gel filtration chromatography may be used as follows.

[0013]

[Table 1] 1. Measurement conditions Temperature: 40 ° C. Solvent: Tetrahydrofuran Flow rate: 0.5 ml / min Sample concentration: 0.1 wt% Sample injection amount; 100 μl

2. Column In order to appropriately measure the molecular weight region of 10 ³ to 1 × 10 ⁷ , the column used is a combination of a plurality of commercially available polystyrene gel columns. In the measurement of the present invention, GMHXL (30 cm ×, manufactured by Tosoh Corporation)
2) were used.

3. Calibration curve Standard polystyrene is used to prepare the calibration curve. The standard polystyrene is, for example, Pressure.
chemical Co. Manufactured by Tosoh Co., Ltd. and having a molecular weight of, for example, 6 × 10 ² , 2.8 × 10 ³ , 6.2.
^{× 10 3, 1.03 × 10 4} , 1.67 × 10 4, 4.
39 × 10 ⁴ , 1.02 × 10 ⁵ , 1.86 × 10 ⁵ ,
4.22 x 10 ⁵ , 7.75 x 10 ⁵ , 1.26 x 10
^It is suitable to use ⁶ and use at least about 10 standard polystyrenes. 4. Detector A RI (refractive index) detector is used as the detector.

On the other hand, the Tg is measured by a known method. For example, a differential thermal analyzer may be used. Also,
The method for polymerizing the resin having Mw of 2.0 × 10 ⁵ used for the measurement of Tg is not particularly limited as long as it is an ordinary radical polymerization, and the weight average molecular weight measured by the gel filtration chromatography is The number average molecular weight ratio (so-called Mw / Mn) is usually 1.8 to 3.5.

As the colorant used in the toner of the present invention together with the above-mentioned binder resin, all known colorants can be used, and examples thereof include carbon black, nigrosine, benzidine yellow, quinacridone, rhodamine B and phthalocyanine blue. Further, the toner of the present invention can be used in both a dry one-component developer and a two-component developer, and as the one-component magnetic material, it is possible to use ferromagnetism such as iron, cobalt, nickel, etc., such as ferrite, magnetite, etc. The alloy shown, or an alloy containing no compound or ferromagnetic element but exhibiting ferromagnetism by appropriate heat treatment, for example, Heusler containing manganese and copper such as manganese-copper-aluminum or manganese-copper-tin. Examples include alloys of the type called alloys, chromium dioxide, and the like. The magnetic material has an average particle size of 0.
It is uniformly dispersed in the binder resin in the form of a fine powder of 3 to 30 μm. The content of the magnetic particles is 100% by weight of the binder.
20 to 70 parts by weight, especially 40 to 70 parts by weight, is particularly preferable.

The charge control of the toner may be performed by the binder resin and the colorant itself, but a charge control agent may be used if necessary. Quaternary ammonium salts, basic / electron-donating organic substances as positive charge control agents, metal chelates, metal-containing dyes, acidic or electron-withdrawing organic substances etc. as negative charge control agents. Can be used. The addition amount of the charge control agent can be determined in consideration of the chargeability of the binder resin, the manufacturing method including the addition amount / dispersion method of the colorant, and the chargeability of other additives. 0.1 to 10 parts by weight is suitable. In addition, inorganic particles such as metal oxides or inorganic substances surface-treated with the organic substance may be used. These charge control agents may be mixed and added to the binder resin, or may be used in the form of being attached to the surface of the toner particles.

Furthermore, a solid electrolyte, a polymer electrolyte, a charge transfer complex, a conductor such as a metal oxide such as tin oxide,
The electrical properties of the toner can be controlled by adding a semiconductor, a ferroelectric substance, a magnetic substance, or the like. In addition, auxiliary agents such as various plasticizers and release agents may be added to the toner for the purpose of adjusting thermal characteristics and physical characteristics. The appropriate amount of addition is 0.1 to 10 parts by weight.

Further, for the toner particles, TiO ₂ ,
By adding fine powder such as Al ₂ O ₃ or SiO ₂ and coating the surface of the toner particle with these, the fluidity and aggregation resistance of the toner can be improved. The addition amount is preferably 0.1 to 10 parts by weight. Various conventionally used toner production methods can be applied to the toner production method of the present invention. For example, the following examples can be given as general production methods. First, a resin and a colorant (such as a charge control agent in some cases) are uniformly dispersed using a ball mill, a V-type mixer, an S-type mixer, a Henschel mixer, or the like. Next, the dispersion is melt-kneaded with a double-arm kneader, a pressure kneader, or the like. The mixture is crushed by a crusher such as a hammer mill, a jet mill and a ball mill, and the obtained powder is classified by an air classifier. The obtained toner can be mixed with a carrier to form a developer for electrophotography, if necessary, and can be used for copying by a conventional electrophotographic method.
As the carrier, it is preferable to use 10 to 100 parts by weight of a known magnetic substance such as an iron powder type carrier, a ferrite type carrier or the like, or a material having a surface coated thereon with respect to 1 part by weight of the toner.

[0021]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, "part" in an Example represents a "weight part." Example 1 Styrene-n-butyl acrylate having a peak at 2.2 × 10 ⁴ synthesized using propylene glycol monomethyl ether as a solvent and benzoyl peroxide as a radical polymerization initiator (monomer weight ratio: 5
0/50, Tg in the case of producing a resin having an Mw of 2.0 × 10 ⁵ : 21.3 ° C.), 60 parts of potassium persulfate as a radical polymerization initiator and potassium laurate as an emulsifier at 60 ° C. Styrene homopolymer having a peak at 6.0 × 10 ⁵ synthesized by emulsion polymerization (Tg at Mw of 2.0 × 10 ⁵ : 108.3
40 ° C.) 40 parts of melt-blended polymer (Mw: 25.6 ×
10 ⁴ , Tg: 55.3 ° C) 100 parts, polypropylene wax ("Viscole 550P" manufactured by Sanyo Kasei Co., Ltd.)
3 parts, carbon black ("# 3" manufactured by Mitsubishi Kasei Co., Ltd.)
0 ") and 2 parts of nigrosine dye (" Bontron N-04 "manufactured by Orient Chemical Co., Ltd.) were dispersed and mixed, and then melt-kneaded using a twin-screw extruder. After cooling, it was coarsely pulverized by a hammer mill and then finely pulverized by a supersonic jet mill pulverizer. The obtained powder is classified with an air classifier, and the average particle size is 1
Toner A of 0.3 μm was obtained. In the examples below,
The low molecular weight component was synthesized by solution polymerization as in Example 1, and the high molecular weight component was synthesized by emulsion polymerization.

Example 2 Styrene-n-butyl acrylate having a peak at 1.0 × 10 ⁴ in GPC (gel filtration chromatogram) (monomer weight ratio: 60/4)
0, Tg at Mw of 2.0 × 10 ⁵ : 31.3 ° C.)
Styrene-n having peaks at 60 parts and 6.0 × 10 ⁵
Butyl acrylate (monomer weight ratio: 90/10, M
Tg when w is 2.0 × 10 ⁵ : 81.0 ° C.) 40 parts of melt-blended polymer (Mw: 24.1 × 10 ⁴ , T
(g: 52.1 ° C.), a toner B having an average particle size of 10.3 μm was obtained in the same manner as in Example 1.

(Embodiment 3) 1.5 × 10 in GPC
Styrene-n-lauryl methacrylate having a peak at ⁴ (monomer weight ratio: 70/30, Mw 2.0 × 10
Tg at ⁵ : 52.3 ° C.) 60 parts and 1.0 × 10 ⁶
Styrene homopolymer (Mw is 2.0
Tg at × 10 ⁵ : 108.3 ° C.) 40 parts of melt-blended polymer (Mw: 38.1 × 10 ⁴ , Tg: 5)
Toner C having an average particle size of 10.3 μm was obtained in the same manner as in Example 1 except that the temperature was 8.1 ° C.).

(Example 4) 2.0 × 10 in GPC
Styrene-phenoxyethyl acrylate having a peak at ⁴ (monomer weight ratio: 50/50, Mw 2.0 ×)
Tg at 10 ⁵ : 40.1 ° C.) 50 parts and 2.0 × 1
Styrene-methyl methacrylate having a peak at 0 ⁶ (monomer weight ratio: 80/20, Mw 2.0 × 10 ⁵
Tg at 109.3 ° C.) 50 parts melt blended polymer (Mw: 19.1 × 10 ⁴ , Tg: 60.3 ° C.)
Average particle size 10.3
Toner D of μm was obtained.

Comparative Example 1 4.3 × 10 in GPC
Styrene homopolymer having a peak at ³ (Mw is 2.
Tg at 0 × 10 ⁵ : 108.3 ° C.) 60 parts and 6.
Styrene homopolymer having a peak at 0 × 10 ⁵ (M
Tg when w is 2.0 × 10 ⁵ : 108.3 ° C.) 40
Part of melt-blended polymer (Mw: 20.1 × 10 ⁴ ,
A toner E having an average particle size of 10.3 μm was obtained in the same manner as in Example 1 except that (Tg: 65.1 ° C.) was used.

Comparative Example 2 1.0 × 10 in GPC
Styrene-n-butyl acrylate having a peak at ⁴ (monomer weight ratio: 90/10, Mw 2.0 × 10 ⁵
Styrene-n-butyl acrylate having a peak at 6.0 × 10 ⁵ (Tg: 81.0 ° C.) (monomer weight ratio: 60/40, Mw: 2.0 × 10 ⁵ Tg: 31.3 ° C.). ) A toner F having an average particle size of 10.3 μm was obtained in the same manner as in Example 1 except that 40 parts of the melt blended polymer (Mw: 22.1 × 10 ⁴ , Tg: 51.2 ° C.) was used.

(Comparative Example 3) 5.2 × 10 in GPC
Styrene homopolymer having a peak at ³ (Mw is 2.
Tg at 0 × 10 ⁵ : 108.3 ° C.) 60 parts and 1.
Styrene-n-lauryl methacrylate having a peak at 0 × 10 ⁶ (monomer weight ratio: 70/30, Mw: 2.
Tg at 0 × 10 ⁵ : 52.3 ° C.) 40 parts of melt-blended polymer (Mw: 36.2 × 10 ⁴ , Tg: 4)
A toner G having an average particle size of 10.3 μm was obtained in the same manner as in Example 1 except that (6.3 ° C.) was used.

(Comparative Example 4) 2.0 × 10 in GPC
Styrene-phenoxyethyl acrylate having a peak at ⁴ (monomer weight ratio: 50/50, Mw 2.0 ×)
Tg at 10 ⁵ : 40.1 ° C.) 50 parts and 9.0 × 1
Styrene-methyl methacrylate having a peak at 0 ⁴ (monomer weight ratio: 80/20, Mw: 2.0 × 10 ⁵
(Tg at 109.3 ° C.) 50 parts melt blended polymer (Mw: 10.1 × 10 ⁴ , Tg: 62.1 ° C.)
Average particle size 10.3
Toner H of μm was obtained.

Using the above toners A to H, a fixing test and a blocking resistance test were conducted according to the following methods. Fixing test: Unfixed toner was passed through a fixing roller of 400 mm / sec, and the lower limit temperature for fixing and the temperature at which hot offset occurred were examined. Anti-blocking test: 50% by applying a constant load to the toner
Whether the blocking property was good or bad after standing for 5 hours in an environment of ° C was judged. The results are shown in Table 1. Toners A to
D was a toner excellent in all of fixing property, anti-offset property and anti-blocking property.

[0030]

[Table 2] ○ Very good × Bad × × Extremely bad

[0031]

According to the present invention described above, the fixability,
A toner having excellent offset resistance and blocking resistance can be obtained.

Claims (6)

[Claims] 1. A glass transition having a weight average molecular weight of 50,000 or more.
The temperature is 50-60 ° C, and the gel filtration chromatogram
The molecular weight is 3 × 10³~ 1 × 10^FiveHas a peak at
Low molecular weight component and molecular weight 1 × 10^Five~ 1 × 10⁷On
It has a weight average molecular weight
2.0 x 10^FiveHas the same monomer composition as the low molecular weight component.
The glass transition temperature of the resin to be used has a weight average molecular weight of 2.0.
× 10 ^FiveWith the same monomer composition as the high molecular weight component
Binder resins and coloring below the glass transition temperature of fats
A toner for developing an electrostatic charge image, which comprises an agent. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the binder resin is a styrene resin. 3. The toner for developing an electrostatic charge image according to claim 1, wherein the low molecular weight component and the high molecular weight component have different monomer compositions. 4. The weight average molecular weight of the binder resin is 12
The toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein the toner has an amount of 10,000 or more. 5. The low molecular weight component has a molecular weight of 4 × 10 ^{3 to} 5 ×.
5. The toner for developing an electrostatic charge image according to claim 1, which has a peak at 10 ⁴ . 6. The high molecular weight component has a molecular weight of 4 × 10 ^{5 to} 5 ×.
^{6. The} toner for developing an electrostatic charge image according to claim 1, which has a peak at 10 ⁶ .