JPH0962027A - Electrostatic charge image developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert an electrostatic latent image having negative polarity into a visible image with high image quality and grade and to form a superior image having the optimum density and almost free from fog by incorporating a resin binder, a colorant, a quat. ammonium salt, a specified toner and a specified carrier. SOLUTION: A resin binder, a colorant, a quat. ammonium salt, a toner contg. a lubricant and a ferrite or magnetite carrier are incorporated. The lubricant in the toner has a peak of heat absorption by measurement with a differential scanning calorimeter(DSC) in the range of 50-130 deg.C and the half- width of the peak is <=15 deg.C. The kind of the used lubricant is not especially limited if the lubricant satisfies prescribed characteristics but it is preferably selected from among fatty acid amides such as lauric acid amide and myristic acid amide, aliphatic ketones such as di-n-decyl ketone and di-n-dodecyl ketone, fatty acid diesters such as didodecyl sebacate and distearyl sebacate and fatty acid monoesters such as behenyl laurate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrostatic image developer. More specifically, the present invention relates to an electrostatic charge image developer that visualizes a negative electrostatic latent image with high image quality by a specific combination of toner and carrier and provides an excellent image with optimum density and less fog.

[0002]

2. Description of the Related Art Conventionally, in a copying machine utilizing an electrophotographic method, in order to visualize an electrostatic latent image formed on a photoconductor having selenium or an organic photoconductor by a dry development method,
A toner in which an additive such as a colorant is dispersed in a binder resin is used. The developing method is to develop an electrostatic latent image formed on a photoconductor by charging and exposure with a toner, transfer the developed toner image to a support such as transfer paper, and heat the toner with a heating roller or a pressure roller. The image is fixed on a support to visualize the electrostatic latent image. After the toner image is transferred to the support, the cleaning member scrapes off the toner remaining on the photosensitive member in order to clean the toner remaining on the photosensitive member, and prepares for the next image forming process.

The above toner is a binder resin containing a colorant,
Resin particles having an average particle size of 1 to 30 μm, in which a charge control agent and a toner property imparting agent such as magnetic particles are dispersed as necessary. In order to faithfully reproduce the original image in the developing process, the toner exhibits excellent fluidity in the developing device, the toner particles have a uniform charge amount, and toner other than latent images due to uncharged and weakly charged particles is used. It is necessary to prevent the generation of fog due to the adherence of the toner and the reduction of the image density due to the accumulation of the toner in the developing device due to the excessively charged particles and the reduction of the adhered amount to the latent image.

[0004]

Generally, in producing a positively chargeable toner, a positive charge control agent such as a nigrosine dye or a quaternary ammonium salt is used in order to reach a desired charge amount as quickly as possible. In many cases, the surface of the carrier used is coated with a fluororesin such as polytetrafluoroethylene or polyvinylidene fluoride or a silicone resin. However, the developer prepared with this formulation has problems such as poor image quality, uniform density of solid black portions, and poor stability of toner charge amount. An object of the present invention is to provide an electrostatic charge image developer which can visualize a negative electrostatic latent image with high image quality and obtain an excellent image with optimum density and less fog.

[0005]

That is, the gist of the present invention is that a binder resin, a colorant, a quaternary ammonium salt, and a differential scanning calorimeter (DSC) measurement of 50 to 13 are used.
A toner containing a lubricant having an endothermic peak in the range of 0 ° C. and having a half-value width of the endothermic peak of 15 ° C. or less, and an electrostatic charge image containing a ferrite carrier or a magnetite carrier. It exists in the developer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The lubricant used in the present invention has an endothermic peak in the range of 50 to 130 ° C. in DSC measurement, and the half width of the endothermic peak is 15 ° C. or less. , Particularly preferably an endothermic peak of 65 to 90 ° C
It is. If the endothermic peak in the DSC measurement is lower than 50 ° C., the toner charge amount will not be stable during continuous copying. It is considered that this is because the lubricant bleeds during continuous copying. On the other hand, when the endothermic peak in the DSC measurement is higher than 130 ° C. or the half width of the endothermic peak is 15 ° C. or more, the toner charge amount is not stable when continuously copied. It is considered that this is because the dispersibility of the lubricant is deteriorated and the toner is not uniformly charged. The lubricant used in the present invention is not particularly limited to the type as long as the above properties are satisfied, but lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide,
Fatty acid amides such as arachidic acid amide, behenic acid amide, oleic acid amide, eicoic acid amide, erucic acid amide, elaidic acid amide, linoleic acid amide, linoleic acid amide, ridinoleic acid amide, and methylenebisamide; di-n-decyl ketone, Di-n-dodecyl ketone,
Di-n-stearyl ketone, di-n-icosyl ketone,
Aliphatic ketones such as di-n-behenyl ketone and di-n-tetracosyl ketone; fatty acid diesters such as didodecyl sebacate, distearyl sebacate and dibehenyl sebacate; stearyl laurate, behenyl laurate, stearic acid Stearyl, behenyl stearate,
Fatty acid monoesters such as stearyl behenate and behenyl behenate are preferred.

In the present invention, two or more kinds of the above lubricants may be combined and contained in the toner. The content of the lubricant is usually 0.5 to 30 with respect to 100 parts by weight of the binder resin.
Parts by weight, preferably 1 to 15 parts by weight, particularly preferably 2 to 10 parts by weight. In the present invention, DSC measurement was performed at a temperature rising rate of 10 ° C./min using DSC7000 (manufactured by Vacuum Riko Co., Ltd.). As the binder resin used in the present invention, known resins such as styrene resins, polyester resins and epoxy resins are used.

As the colorant used in the toner of the present invention,
All known substances can be used, for example, carbon black, nigrosine, benzidine yellow, quinacridone,
Rhodamine B and phthalocyanine blue are available. The colorant is preferably contained in an amount of 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the binder resin. The quaternary ammonium salt preferably used in the present invention is represented by the following general formula (I):
Examples thereof include compounds represented by (VII).

[0009]

Embedded image

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ may be the same or different from each other, and each is a substituted or unsubstituted aromatic carbocyclic group or a substituted or unsubstituted aromatic heterocyclic group. , Or a substituted or unsubstituted aliphatic hydrocarbon group,
X ^n- represents an anion and n represents a natural number. In addition, R ₁ ~
The carbon number of R ₄ is preferably 1 to 22 each. )

[0011]

Embedded image

(Wherein R ₅ and R ₆ are each independently hydrogen or a substituted or unsubstituted hydrocarbon group, or R ₅ and R ₆ are linked to each other to form a substituted or unsubstituted aromatic group. R ₇ represents hydrogen or a substituted or unsubstituted hydrocarbon group, R ₈ and R ₉ independently represent a substituted or unsubstituted hydrocarbon group, and X ^n- is an anion. And n represents a natural number, and when R ₅ , R ₆ or R ₇ is a hydrocarbon group, the number of carbon atoms is preferably 22 or less,
In the case of R ₈ and R ₉ , each is preferably 8 or less. )

[0013]

Embedded image

(In the formula, R ₁₀ and R ₁₁ may be the same or different from each other, and each is a substituted or unsubstituted aromatic carbocyclic group, a substituted or unsubstituted aromatic heterocyclic group, a hydrogen atom (R
₍ Excluding the case of ₁₀ ), or a substituted or unsubstituted aliphatic hydrocarbon group, X ^n- represents an anion, and n represents a natural number. The carbon number of R ₁₀ and R ₁₁ is preferably 22 or less. )

[0015]

Embedded image

(Wherein R₁₂, R₁₃And R₁₄Are identical to each other
Alternatively, they may be different, and the substituted and unsubstituted
Aromatic carbocyclic group, substituted or unsubstituted aromatic heterocyclic group, hydrogen source
Child (R ₁₄Except), or substituted or unsubstituted aliphatic
Represents a hydrocarbon group, Y represents C, O or S (C
In the case of, may have a substituent), X^n-Is anion
And n represents a natural number. Note that R₁₂And R₁₃Carbon of
Each number is preferably 22 or less. )

[0017]

Embedded image

(Where R_Fifteen, R₁₆And R₁₇Are identical to each other
Alternatively, they may be different, and the substituted and unsubstituted
Aromatic carbocyclic group, substituted or unsubstituted aromatic heterocyclic group, hydrogen source
Child (R _FifteenExcept), or substituted or unsubstituted aliphatic
Represents a hydrocarbon group, X^n-Is an anion and n is a natural number
Represent. Note that R_Fifteen, R₁₆And R₁₇The carbon number of
22 or less is preferable. )

[0019]

[Chemical 6]

(In the formula, R ₁₈ and R ₁₉ may be the same or different from each other, and each is a substituted or unsubstituted aromatic carbocyclic group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted,
It represents an unsubstituted aliphatic hydrocarbon group, X ^n- represents an anion, and n represents a natural number. The carbon number of R ₁₈ and R ₁₉ is preferably 22 or less. )

[0021]

[Chemical 7]

(In the formula, R ₂₀ represents a substituted or unsubstituted aromatic carbocyclic group, a substituted or unsubstituted aromatic heterocyclic group or a substituted or unsubstituted aliphatic hydrocarbon group, and X ^n- is an anion. , N
Represents a natural number. The carbon number of R ₂₀ is preferably 22 or less. ) Examples of the substituent that the aromatic ring formed by R _{1 to} R ₂₀ , and R ₅ and R ₆ may have include an alkyl group (excluding substitution with an alkyl group), an aryl group, an aralkyl group, Examples thereof include a hydroxyl group, an amino group, a halogen group, and a heterocyclic residue. Furthermore, ether bond, thioether bond,
Or, via an amide bond or the like, an alkyl group, an aryl group,
It may have a substituent such as an aralkyl group or a heterocyclic residue.

As the anion of the quaternary ammonium salt that can be used in the present invention, various known anions can be used and are not particularly limited, but halogen ions such as chloride ion and bromide ion, methane sulfonate ion, ethane sulfonate ion. Ion, propanesulfonate ion, propanedisulfonate ion, propanetrisulfonate ion, benzenesulfonate ion, benzenedisulfonate ion, benzenetrisulfonate ion, naphthalenesulfonate ion, naphthalenedisulfonate ion, naphthalenetrisulfonate ion, Organic sulfonate ions such as quinoline sulfonate ion; methyl organic sulfonate ion, ethyl organic sulfonate ion, propyl organic sulfonate ion, hydroxy organic sulfonate ion, anilino organic sulfonate ion, etc. An organic polysulfonate ion; an isopolyacid ion such as a dimolybdate ion, a tetramolybdate ion, a hexamolybdate ion, and an octamolybdate ion; and an anion such as a heteropolyacid ion such as a tungstophosphate ion, a halogen ion, Organic sulfonate ions and substituted organic sulfonate ions are preferred. Among the compounds represented by formulas (I) to (VII), acyclic quaternary ammonium salts are particularly preferable, and specific examples thereof are shown below, but the invention is not limited thereto.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

The quaternary ammonium salt is a binder resin 1
The content is preferably 0.1 to 10% by weight, more preferably 0.5 to 5 parts by weight, based on 00 parts by weight. In addition, inorganic particles such as metal oxides or inorganic substances surface-treated with organic substances may be used for the toner. These may be used by being mixed and added to the binder resin, or may be used by being attached to the surface of the toner particles. Further, the electrical properties of the toner can be controlled by adding a solid electrolyte, a polymer electrolyte, a charge transfer complex, a conductor such as a metal oxide such as tin oxide, a semiconductor, a ferroelectric substance, a magnetic substance or the like. . In addition, various additives such as plasticizers and release agents may be added to the toner for the purpose of adjusting thermal characteristics or physical characteristics. The appropriate addition amount is 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. Furthermore, for the toner particles, TiO ₂ , A
It is possible to improve the fluidity and aggregation resistance of the toner by adding fine powder such as 1 ₂ O ₃ or SiO ₂ and coating the surface of the toner particle with these powders. The amount of addition is 0.1-10 with respect to 100 parts by weight of the binder resin.
Parts by weight are preferred. Further, a charge control agent other than the quaternary ammonium salt is mixed and added to the binder resin, or
The toner particles may be used in a form of being attached to the surface of the toner particles, but in this case, it is preferable to use a positively chargeable charge control agent together. The toner in the present invention is preferably a positively chargeable toner.

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, a colorant, a quaternary ammonium salt, a lubricant, and, if necessary, other raw materials are uniformly dispersed with 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 or a ball mill, and the obtained powder is classified by an air classifier or the like. The particle size of the toner is usually 1 to 30 μm.

The obtained toner can be mixed with a carrier to form a developer for electrophotography, and can be used for copying by a conventional electrophotographic method. In the present invention, a magnetite carrier or a ferrite carrier is used as the carrier. Both may be used as a mixture,
It is preferably used alone. The ferrite carrier used in the present invention includes CuOFe ₂ O ₃ ZnO and NiOF.
Although e ₂ O ₃ ZnO can be given as an example, all known ones can be used and are not particularly limited. Both carriers may be used with their surfaces coated with a resin or the like. The coating resin in the case of coating, polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, a fluorine-based polymer such as vinylidene fluoride-trifluoroethylene copolymer, silicone resin, styrene -Acrylic copolymers are mentioned, but not limited thereto. Further, it may be covered with a metal oxide. The particle size of the carrier is usually 50 μm to 300 μm. The carrier is usually used in an amount of 10 to 100 parts by weight with respect to 1 part by weight of the toner.

[0030]

Hereinafter, embodiments of the present invention will be described.
The present invention is not limited to these examples.
In addition, "part" in an Example represents a "weight part." The molecular weight means a weight average molecular weight unless otherwise specified. (Example 1) Cross-linking type styrene / n-butyl acrylate resin (composition: 80/20 weight ratio, insoluble matter in tetrahydrofuran 30% by weight, soluble matter molecular weight distribution is 1.0 × 10 ⁴ and 2 ×). Resin having a weight average molecular weight of 8.0 × 10 ⁴ each having a peak at 10 ⁵ ) 100
Part, 5 parts of di-n-stearyl ketone (endothermic peak in DSC measurement: 87.5 ° C., full width at half maximum: 6 ° C.), 3 parts of “Viscor 550P” manufactured by Sanyo Kasei Co., Ltd., carbon black (Mitsubishi Chemical Corporation )) "# 30") and 4 parts of a quaternary ammonium salt (exemplified compound (6)) are dispersed and mixed,
Melt kneading was performed 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,
A toner having an average particle size of 10.3 μm was obtained. 5 parts of this toner is used as a ferrite carrier (“F” manufactured by Powder Tech Co., Ltd.).
L96-100 ") was mixed with 100 parts of a V-type mixer to obtain a developer A.

(Example 2) Styrene / n-butyl acrylate resin (composition: 80/20 weight ratio, molecular weight distribution:
Developer B was obtained in the same manner as in Example 1 except that 100 parts of each having a molecular weight of 4.5 × 10 ³ and a peak of 6.5 × 10 ⁵ were used. (Example 3) The same procedure as in Example 1 was repeated except that 5 parts of sebacic acid distearyl ester (endothermic peak in DSC measurement: 70.5 ° C, full width at half maximum: 6 ° C) was used instead of di-n-stearyl ketone. Developer C is obtained.

(Example 4) Styrene used in Example 2 /
Developer D was obtained in the same manner as in Example 3 except that the n-butyl acrylate resin was used. (Example 5) Behenyl behenate was used instead of di-n-stearyl ketone (endothermic peak in DSC measurement: 76.0).
C., full width at half maximum: 8 ° C.) A developer E was obtained in the same manner as in Example 1 except that 5 parts were used.

Example 6 Developer F was prepared in the same manner as in Example 1 except that 2 parts of the quaternary ammonium salt of Exemplified compound (4) was used instead of the quaternary ammonium salt of Exemplified compound (6).
I got (Example 7) A developer G was obtained in the same manner as in Example 1 except that a magnetite carrier coated with a silicone resin was used instead of the ferrite carrier.

Comparative Example 1 A developer H was obtained in the same manner as in Example 1 except that a nigrosine dye (“Bontron N-04” manufactured by Orient Chemical Co., Ltd.) was used in place of the quaternary ammonium salt. (Comparative Example 2) Hydrogenated castor oil in place of di-n-stearyl ketone (endothermic peak in DSC measurement: 85.0 ° C,
Full width at half maximum: 24.8 ° C.) Developer I was obtained in the same manner as in Example 1 except that 5 parts was used.

Comparative Example 3 Example 1 was repeated except that 5 parts of low molecular weight polyethylene (endothermic peak in DSC measurement: 135.0 ° C., full width at half maximum: 11.0 ° C.) was used instead of di-n-stearyl ketone. Developer J was obtained in the same manner. (Comparative Example 4) The same as Example 1 except that 5 parts of ethylenebisstearic acid amide (endothermic peak in DSC measurement: 141.5 ° C, full width at half maximum: 10.1 ° C) was used instead of di-n-stearyl ketone. To obtain a developer K. Using the above developers A to K, a continuous copy test was conducted with an SF-9700 copying machine (manufactured by Sharp Corporation) to examine changes in image density (ID) and fog. The results are shown in the table below.

[0036]

[Table 4]

RD-917 (manufactured by Macbeth Co.) was used to measure the image density, and Z-II OP was used to measure the fog.
TICAL SENSOR (manufactured by Nippon Denshoku Industries Co., Ltd.) was used.

[0038]

By using the developer according to the present invention, a stable toner charge amount can be obtained, and an excellent image can be obtained without a change in image quality such as a decrease in image density and an increase in fog during continuous copying.

Claims (2)

[Claims] 1. A binder resin, a colorant, a quaternary ammonium salt, and 50 to 13 in a differential scanning calorimeter measurement.
A toner containing a lubricant having an endothermic peak in the range of 0 ° C. and having a half-value width of the endothermic peak of 15 ° C. or less, and an electrostatic charge image containing a ferrite carrier or a magnetite carrier. Developer. 2. A binder resin 100 containing a lubricant.
The electrostatic image developer according to claim 1, which is 0.5 to 30 parts by weight with respect to parts by weight.