JPH0611905A - Toner for developing electrostatic latent image - Google Patents

Abstract

PURPOSE:To provide a long-life toner that provides high picture quality at copying repeated over a long period and is excellent in charge characteristics by putting acidic carbon black and a specific compound in the toner. CONSTITUTION:A toner contains at least resin, acidic carbon black and a compound expressed by the formula. In the formula, R1-R4 each represents a substituted or unsubstituted alkyl or aralkyl group, preferably e.g. a dodecyl, tridodecyl, stearyl, benzyl or substituted benzyl group; (A) represents an aromatic ring residue that may have a substituted group, preferably a benzene or naphtalene ring, and, a hydroxyl, amino and alkyl group are mentioned as examples of the substituted group, among which the hydroxyl group is preferred; (N) represents an integer of two or more, preferably 2 or 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography and the like.

[0002]

BACKGROUND OF THE INVENTION Electrophotography is described in US Pat. No. 2,297,691.
Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-2
As disclosed in various publications such as Japanese Patent No. 4748, a toner in which an electrostatic latent image of electrostatic charge is formed on a photoconductor containing a photoconductive material by various means, and then the latent image is precharged in advance. It is developed as a powder image by means of, and if necessary, the powder image is transferred to paper or the like, and then fixed by heating, pressurizing or solvent vapor.

At this time, as a developer for developing the electrostatic latent image formed on the photoconductor, the toner is carried by the magnetic force to the vicinity of the photoconductor while carrying the toner on the surface with the electrostatic force. 30-200 particle size called carrier
Known are two-component developers consisting of iron powder of about μm, ferrite, magnetite, etc., and one-component developers consisting of only toner without the need for a carrier.

The toner is a powder in which a colorant (dye, pigment), a charge control agent and the like are dispersed in a binder resin such as styrene-acrylic and is finely pulverized to about 1 to 30 μm. Nigrosine type dyes, triaminophenylmethane type compounds, 4
Charge control agents such as primary ammonium salts have been known.

[0005]

However, these conventional charge control agents are not always sufficient in the effect of imparting chargeability, and in particular, fog (image stains on a white background), reduction in image density, etc., during repeated copying for a long period of time. However, there is a problem that the image quality deteriorates.

In order to solve these problems, it is needless to say that a proper charge amount is given at the initial stage, but a toner having a small charge change in repeated copying for a long time and having excellent charge characteristics is developed. is important. An object of the present invention is to provide a toner for developing an electrostatic charge image, which has high image quality in long-term repeated copying and has excellent charging characteristics.

[0007]

SUMMARY OF THE INVENTION As a result of intensive studies to solve such problems, the present invention has led to a compound having a specific structure with acidic carbon black, which has conventionally been avoided because it tends to be negatively charged. The present invention was found to provide a toner having high image quality, excellent charging properties, and long life by repeated addition in a toner for long-term repeated copying.

The present invention will be described in detail below. The compound having a specific structure according to the present invention is represented by the following general formula [1]. General formula [1]

[0009]

[Chemical 2]

(In the formula, R ¹ , R ² , R ³ and R ⁴ each represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group, and A is an aromatic group which may have a substituent. Represents a ring residue, and n represents an integer of 2 or more.) Specific examples of the substituents R ¹ , R ² , R ³ and R ^{4 in} the general formula [1] include a methyl group, an ethyl group and a propyl group. ,
Isopropyl group, n-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonanyl group, decyl group,
Undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, stearyl group, and other alkyl groups; benzyl group and other aralkyl groups; lower alkyl-substituted benzyl group, nitro-substituted benzyl group, halogen-substituted benzyl group And the like, and among them, dodecyl group, tridodecyl group, tetradecyl group, hexadecyl group, stearyl group, benzyl group, and substituted benzyl group are preferable. It is also preferred that R ¹ and R ² are methyl groups, and the total number of carbon atoms of R ³ and R ⁴ is 13 or more, preferably 19 or more, more preferably 30 or more. .

A in the general formula [1] represents an aromatic ring residue which may have a substituent, particularly preferably a benzene ring or a naphthalene ring, and the substituent is a hydroxyl group, an amino group or an alkyl group. And a hydroxyl group is particularly preferable.
It may have two or more substituents. n represents an integer of 2 or more, preferably 2 or 3.

Among the general formulas [1], those represented by the following general formulas are particularly preferable.

[0013]

[Chemical 3]

(Wherein R ³ and R ⁴ represent an alkyl group,
The total carbon number of R ³ and R ⁴ is 19 to 50, and the naphthalene ring may have a hydroxyl group as a substituent. Among these, those represented by the following general formula [3], [4] or [5] are particularly preferable.

[0015]

[Chemical 4]

[0016]

[Chemical 5]

[0017]

[Chemical 6] Among the compounds represented by the general formula [1], specific examples of the compounds suitable for being contained in the toner for developing an electrostatic image of the present invention include the compounds represented by the following structural formulas. It is not limited to these. Exemplified compound A

[0018]

[Chemical 7]

[0019]

[Chemical 8]

[0020]

[Chemical 9]

[0021]

[Chemical 10]

[0022]

[Chemical 11]

[0023]

[Chemical 12]

[0024]

[Chemical 13]

[0025]

[Chemical 14]

[0026]

[Chemical 15]

[0027]

[Chemical 16]

[0028]

[Chemical 17]

[0029]

[Chemical 18]

[0030]

[Chemical 19]

[0031]

[Chemical 20]

[0032]

[Chemical 21]

[0033]

[Chemical formula 22]

[0034]

[Chemical formula 23]

(18) In the general formula [I], R ¹ = CH
₃ , R ² = CH ₃ , R ³ = C ₈ H ₁₇ , R ⁴ = benzyl group, A = 1,5-naphthalenedisulfonate ion (19) In the general formula [I], R ¹ = CH ₃ , R ² = C
H ₃ , R ³ = benzyl group, R ⁴ = benzyl group, A = 1,
5-naphthalene disulfonate ion exemplified compound B

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

The compound represented by the general formula [1] can be used in the present invention irrespective of its production method, and an example of its specific production method will be described below. The compound represented by the general formula [1] is generally, for example, the following general formula [II]

[0043]

[Chemical formula 24]

The halogenated quaternary ammonium salt compound represented by the formula (I) is reacted with the compound represented by the following general formula (III) or general formula (IV) in water or alcohol by heating at about 70 ° C. It is obtained by

[0045]

[Chemical 25]

(In the formula, A has the same meaning as in the general formula [1], and Y represents an alkali metal such as sodium and potassium.) The content of the compound represented by the general formula [1] in the toner is a binder. The amount is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resin.

If the content of the compound represented by the general formula [1] is too small, the effect of imparting the charging property cannot be obtained, and if it is too large, the improvement of the charging property cannot be expected. Acidic carbon black is used as the colorant contained in the toner according to the present invention. The acidic carbon black means that the pH value of the suspension after boiling the carbon black and pure water is 6 or less, and the acidic carbon black having a pH of 2 to 5 is particularly suitable for the present invention. used. The amount of the colorant is preferably 3 to 20 parts by weight with respect to 100 parts by weight of the resin.

Conventionally, acidic carbon black tends to be negatively charged as compared with neutral or alkaline carbon black, so that it tends to be avoided by positively charged toner. The carbon black not only plays a role as a colorant but also plays a role as a resistance adjusting agent as an electric conductor, which also affects the charging property of the toner. It is important that the toner is uniformly dispersed in the toner for coloring power and stability of charging. Styrene acrylic resin, polyester resin, epoxy resin, etc., which are generally used as a binder resin for toner, have an inherently negative charge property, so acidic carbon black is more likely to be uniformly dispersed, which should be advantageous. The positively charged toner tends to have too low a charging characteristic. On the other hand, the compound represented by the general formula [1] has an excellent positive charge imparting property, so that the negative effect of the acidic carbon black can be offset, and the synergistic effect of the acidic carbon black and the general formula [1] can be offset. Therefore, it is presumed that a positively chargeable electrostatic image developer toner having excellent charging characteristics can be obtained.

Specific examples of commercially available acidic carbon blacks include MA7, MA8 and MA11 manufactured by Mitsubishi Kasei.
MA100, # 1000, # 2200B, # 2350,
# 2400B, Cabot MOGUL L, RE
GAL 400R, MONARCH 1000, etc. RAVEN series 1035, 104 made by Colombia
0, 1255, 3500, etc., the specific surface area by the BET method is 25 to 400 m ² / g, the dibutyl phthalate (DBP) oil absorption amount is preferably 40 to 140 ml / 100 g, and the specific surface area is particularly preferably 80 to 150 m ² / g. , Dibutyl phthalate (DBP) oil absorption is 50 ~ 120ml / 100
The range of g is more preferable. It is also preferable to add a small amount of acidic carbon black treated with a metal salt of a carboxylic acid having a melting point of 70 to 250 ° C., if necessary.

The binder resin to be contained in the toner according to the present invention can be selected from a wide range including known ones, for example, polystyrene, crotopoistyrene, poly-α-.
Methylstyrene, styrene-chlorostyrene copolymer,
Styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-
Vinyl acetate copolymer, styrene-maleic acid copolymer,
Styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-phenyl acrylate Copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer and styrene-phenyl methacrylate copolymer) ), Styrene-α-chloromethyl acrylate copolymers and styrene-acrylonitrile-acrylic acid ester copolymers and other styrene-based resins (styrene or styrene-substituted homopolymers or copolymers), vinyl chloride resin, Rosin-modified maleic acid resin,
There are phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, etc.,
A particularly preferred resin for use in the present invention is styrene-
Examples thereof include acrylic acid ester copolymers, styrene-methacrylic acid ester copolymer resins, saturated or unsaturated polyester resins and epoxy resins.

The above resins are not limited to being used alone, but may be used in combination of two or more kinds. If necessary, the toner according to the present invention may be added from a wide range including known materials such as a release agent. Known release agents can be used. For example, low molecular weight polypropylene resin and polyethylene resin. The amount used is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the resin.

In addition, TiO ₂ , Al
It is also possible to improve the fluidity and aggregation resistance of the toner by adding an inorganic fine powder such as ₂ O ₃ or SiO ₂ and coating the surfaces of the toner particles with these. The addition amount is 0.
About 0.1 to 3.0% by weight is preferable. The toner of the present invention can be used not only as a two-component developer but also as a so-called one-component developer such as an encapsulated toner, a polymerized toner and a magnetite-containing 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. Resin first
The colorant and the like are uniformly dispersed with a ball mill, a V-type mixer, an S-type mixer, a Henschel mixer, or the like. Then, the dispersion is melt-kneaded by a double-arm kneader, a pressure kneader, an extruder, a roll mill or the like. The kneaded product is crushed by a crusher such as a hammer mill, a cutter mill, a jet mill, a ball mill, and the obtained powder is classified by an air classifier to obtain a toner having a desired particle size distribution.

As the carrier for forming the developer by mixing with the toner of the present invention, known materials such as ferrite, magnetite and iron powder having a particle size of 20 to 500 μm, more preferably 30 to 200 μm can be used. Further, those whose surface is coated with a silicone resin, an acrylic resin, a fluororesin, a saran resin, or the like, or a mixture of these resins can be preferably used.

In order to prepare a developer by mixing the toner of the present invention with a carrier, it depends on the particle size and shape of the carrier and the particle size of the toner, but usually, the weight ratio is carrier: toner = 99: 1. It is good to do it in the range of about 9: 1. Various mixers such as a V blender, a ball mill type mixer, a reciprocal shaker, and a shaker can be used for mixing.

[0056]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, in each of the examples and the comparative examples, simply "part" means "part by weight".

[Production Example of (12) of Exemplified Compound A] 2 liters of demineralized water was placed in a 3 liter four-necked flask, and distearyl dimethyl ammonium chloride 1 was added.
00g (0.17mol) was added and the water temperature was raised to 80 ° C. 1
The solution was stirred at 220 to 250 rpm for dissolution.
A solution in which 34 g (0.10 mol) of sodium 1,5-naphthalenedisulfonate was dissolved in advance with 200 ml of demineralized water at 80 ° C. was mixed with the above chloride aqueous solution for 30 minutes.

After stirring the mixed solution at 80 ° C. for 2 hours to carry out the reaction, the mixture was allowed to cool while stirring for 2 hours, and then 1
I left it all day and night. To the granular crystals obtained by filtering the liquid, 1 liter of demineralized water was added, and the mixture was stirred at 170 rpm for 30 minutes for washing, and after filtration, the same washing operation was performed and filtration was performed again. , Target bis (distearyldimethylammonium) after drying for 12 hours
Crude crystals of 1,5-naphthalenedisulfonate were obtained as pale yellowish crystals (115.9 g, yield 97.9%). The powder X-ray diffraction pattern was as shown in FIG.

For recrystallization, 100 g of the crude crystal was placed in a 3 liter four-necked flask together with 1 liter of methanol.
After refluxing for 0 minutes, the mixture was cooled with ice and stirred at a liquid temperature of about 2 ° C. for 30 minutes. Precipitated crystals are filtered and dried with a vacuum dryer to 30
78 g of purified crystals after drying at ℃ for 6 hours (total yield 76.4
%) And a melting point of 272 ° C. (decomposition) were obtained. The powder X-ray diffraction pattern of the obtained bis (distearyldimethylammonium) 1,5-naphthalenedisulfonate is shown in FIG. 2, and the solid state C ¹³ -NMR measured under the following conditions is shown in FIG.

[0060]

Table 7 Equipment used: NMR Bruker MSL-3
00 Measurement condition: ¹³ C-CP / MAS method Wait time 5s Accumulation count 350 times Contact time 1ms Rotation speed 5.5kHz

Example 1

[Table 8] Styrene-n-butyl acrylate copolymer resin 100 parts (monomer ratio = 82/18) 5 parts acidic carbon black (MA8 pH = 3.0 manufactured by Mitsubishi Kasei Co., Ltd.) (1) 1 part Polypropylene wax 2 parts (550P Sanyo Kasei Co., Ltd.)

The above materials were heated to 150 using a hot roll mill.
The mixture was melt-kneaded at 0 ° C., cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The obtained fine powder was classified to select a particle size of 5 to 20 μm to obtain a toner having an average particle size of 10 μm. For this toner particle, silica fine powder (R972 Nippon Aerosil)
Was externally added by a Henschel mixer in an amount of 0.3% by weight to obtain a black toner.

This toner was mixed with a carrier obtained by coating a ferrite powder having an average particle diameter of 100 μm with a methyl silicone resin in a V blender at a ratio of 4 parts of toner to 96 parts of carrier to obtain a developer (positive charging property). . A continuous copying test of 100,000 sheets was conducted for this developer using a dry copying machine using a commercially available organic photoconductor as a photoreceptor. As a result, the charge amount was stable, the fog was small, the black portion of the copy had high density and uniformity, and a high-quality image having excellent gradation was obtained.

EXAMPLE 2 As acidic carbon black, MA-100 (pH = 3.5)
A toner and a developer were prepared in exactly the same manner as in Example 1 except that Mitsubishi Kasei Co., Ltd. was used. A continuous copying test of 100,000 sheets was conducted for this developer using a dry copying machine using a commercially available organic photoconductor as a photoreceptor. As a result, the charge amount remained stable, the fog was small, the black portion of the copy had high density and uniformity, and a high-quality copy having excellent gradation was obtained.

Example 3 As acidic carbon black, RAVEN1255 (pH =
2.5 Toner and developer were prepared in exactly the same manner as in Example 1 except that (12) of Exemplified Compound A was used. A continuous copying test of 100,000 sheets was conducted for this developer using a dry copying machine using a commercially available organic photoconductor as a photoreceptor. As a result, the charge amount remained stable, the fog was small, the black portion of the copy had high density and uniformity, and a high-quality copy having excellent gradation was obtained.

Comparative Example 1 A toner and a developer were prepared in the same manner as in Example 1 except that # 44 (pH = 8.0, manufactured by Mitsubishi Kasei Co., Ltd.) was used as the carbon black. This developer was used in a dry copying machine using a commercially available organic photoconductor as a photoconductor.
A continuous live-action test of 10,000 sheets was performed. As a result, the electrification amount was increased and the fog was not a problem, but the density of the black characters in the copy was decreased and the characters were blurred, so that a high quality image could not be obtained.

Comparative Example 2 A toner and a developer were prepared in the same manner as in Example 3 except that # 45 (pH = 8.0 manufactured by Mitsubishi Kasei Co., Ltd.) was used as carbon black. This developer was used in a dry copying machine using a commercially available organic photoconductor as a photoconductor.
A continuous live-action test of 10,000 sheets was performed. As a result, the initial image quality was not a problem, but the charge amount increased as the copying was repeated, the density of the black portion of the copy was low, and there was no uniformity and only a low-quality image was obtained.

[0068]

EFFECT OF THE INVENTION The toner of the present invention is a toner having an excellent charging property, which can maintain the initial high-quality image quality without deteriorating in repeated copying for a long time.

[Brief description of drawings]

FIG. 1 is a powder X-ray diffraction pattern of a crude crystal of exemplary compound (12).

FIG. 2 is a powder X-ray diffraction pattern of a purified crystal of Exemplified compound (12).

FIG. 3 Solid C ¹³ − of purified crystals of Exemplified Compound (12)
NMR diagram.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Ono 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd. Research Institute

Claims (1)

[Claims] 1. An electrostatic image developing toner comprising at least a resin, acidic carbon black and a compound represented by the following general formula [1]. General formula [1] (In the formula, R ¹ , R ² , R ³ and R ⁴ each represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group, and A is an aromatic ring residue which may have a substituent. Represents, and n represents an integer of 2 or more.)