JP2000147824A - Near infrared absorber for electrophotographic toner and toner containing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a near infrared absorber for the electrophotographic toner capable of enhancing the efficiency of absorption of light energy and conversion of light energy into heat energy and fixation strength in flash fixation by using the specified near infrared absorber. SOLUTION: The near infrared absorber to be used is represented by the formula in which each of R1 and R2 is, independently, an optionally substituted alkyl group; R3 is an H atom or a nitro or NH2 group optionally substituted by R4 and 5; each of R4 and R5 is, independently, an optionally substituted alkyl or such aryl or such alkyol- or aryl-carbonyl or such alkyl- or aryl-sulfonyl group; and M is 2 H atoms, or divalent metal atom, or tri- or tetra-valent substituted metal atom or oxy-metal atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a near-infrared absorber for electrophotographic toner used for developing an electrostatic latent image in electrophotography, and an electrophotographic toner containing the near-infrared absorber. More specifically, the present invention relates to a near-infrared absorbing agent for an electrophotographic toner and an electrophotographic toner which give a fixed image having particularly high fixing strength in a flash fixing method.

[0002]

2. Description of the Related Art Conventionally, electrophotography uses a photoconductive insulator, applies a uniform electrostatic charge to the photoconductive insulator by corona discharge or the like, and uses various means to form the photoconductive insulator. Forming an electrostatic latent image by irradiating a light image on the insulator,
Next, the latent image is developed and visualized using toner, and if necessary, a toner image is transferred onto a recording medium such as paper, and then the recording medium is pressed, heated, irradiated with solvent vapor, light, or the like. A copy is obtained by fixing the toner image thereon. The toner image transferred onto the recording medium adheres to the recording medium in a powder state to form an image. For example, the image is destroyed by rubbing with a finger. In order to fix a toner image on a recording medium, it is necessary to melt the toner and fix it on the recording medium. As the method, the above-mentioned pressurization, heating,
There are means such as irradiation with solvent vapor and light. Among them, flash fixing, which is a light fixing method, is a method of fixing by flash light (800 to 1000 nm) of a discharge tube such as a xenon flash lamp, and has the following features.

[0005] Because of non-contact fixing, the resolution of an image during development is not degraded. Quick start is possible without waiting after power-on. It does not fire even if the recording medium is clogged in the fixing unit due to the system down. Glued paper, preprinted paper, paper of different thickness, etc.
Fixing is possible regardless of the material and thickness of the recording medium.

In this flash fixing method, when a flash of a discharge tube of a xenon flash lamp is irradiated, the toner absorbs the light energy of the flash and the temperature rises to soften and melt.
Adheres and penetrates the recording medium. After the flash irradiation is over,
The temperature drops and solidifies to form a fixed image, and fixing is completed.
The image is fixed on the recording medium, and the collapse of the image is eliminated.

[0005] In this flash fixing method, in the conventional color toner, although the colorant has absorption in the visible region, absorption in the near infrared region is weak, conversion efficiency into heat energy is poor, and sufficient fixing cannot be obtained. . Further, in the black toner, although a black coloring material such as carbon black as a colorant has an absorbing ability also in a near-infrared region, its conversion efficiency to heat energy is not sufficient, and various problems are caused. Have.

One of the important characteristics in fixing a flash fixing toner is that the toner needs to efficiently absorb flash light and convert light energy into heat energy. Such absorption of light energy and light energy /
In order to obtain properties relating to thermal energy conversion, toners have been proposed in which an inorganic compound such as carbon black or an organic compound near-infrared absorbing dye is added and dispersed.

For example, in JP-A-58-102247, a cyanine dye is disclosed, and in JP-A-60-57858, a benzenedithiol-based metal complex dye is disclosed in JP-A-Hei.
JP-A-191492 discloses an aminium-based dye. These dyes have poor heat resistance of the dye itself, for example, are thermally decomposed when heated and melt-kneaded with a binder resin to produce a toner, and the near-infrared absorbing ability is reduced. It has various problems, such as insufficient light-to-heat conversion, and has not reached a satisfactory fixing strength. Other near-infrared absorbing dyes have also been proposed, but some dyes are colored because they themselves absorb in the visible region. However, there was a problem that the recording of No. was not obtained, and the fixing strength was poor due to insufficient light-to-heat conversion.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a near-infrared absorber for toner for electrophotography, which has improved light energy absorption and light / heat energy conversion efficiency, and has enhanced fixing strength by flash fixing. An object of the present invention is to provide an electrophotographic toner containing an absorbent.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, a near-infrared ray absorber represented by the following general formula (1) is used as a near-infrared ray absorber for electrophotographic toner. It has been found that the use of an absorber has excellent properties of light energy absorption and light energy / thermal energy conversion efficiency, and the present invention has been completed.

That is, the near-infrared absorber for electrophotographic toner of the present invention is a near-infrared absorber represented by the following general formula (1).

[0011]

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(Wherein, R ₁ and R ₂ each independently represent an optionally substituted alkyl group; R ₃ represents a hydrogen atom, a nitro group or a nitrogen atom substituted with R ₄ or R ₅ ; R ₄ and R ₅ may be the same or different, and each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkylcarbonyl group , An optionally substituted arylcarbonyl group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl group, and M represents two hydrogen atoms, a divalent metal atom, trivalent or It represents a tetravalent substituted metal or an oxymetal.) Further, the present invention relates to an electrophotographic toner containing the near-infrared absorbing agent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The near-infrared absorbing agent for an electrophotographic toner of the present invention is a near-infrared absorbing agent represented by the general formula (1). In the general formula (1), R ₁ and R ₂ each independently represent an optionally substituted alkyl group; R ₃ represents a hydrogen atom, a nitro group or a nitrogen atom substituted with R ₄ or R ₅ ; May be the same or different from each other,
R ₄ and R ₅ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkylcarbonyl group, an optionally substituted arylcarbonyl group Represents an optionally substituted alkylsulfonyl group or an optionally substituted arylsulfonyl group, and M represents two hydrogen atoms, a divalent metal atom, a trivalent or tetravalent substituted metal, or an oxymetal. Show.

The near-infrared absorbing agent of the present invention includes isomer compounds having different substituent positions of the substituent R ₃ and substituents R ₁ , R ₂ , R ₃ , R ₄ and R _{5 which} are by-produced in the synthesis. May also be included.

Hereinafter, the present invention will be described in detail.
It is not limited to these.

In the general formula (1), in R ₁ and R ₂ , the alkyl group which may be substituted includes a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group. -Butyl group, sec-butyl group, tert
-Butyl group, n-pentyl group, iso-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group,
sec-hexyl group, n-heptyl group, iso-heptyl group, sec-heptyl group, n-octyl group, alkyl group such as 2-ethylhexyl group, chloroethyl group, bromoethyl group, halogenoalkyl group such as trifluoromethyl group, Methoxymethyl group, methoxyethyl group, ethoxyethyl group, propoxyethyl group, alkoxyalkyl group such as butoxyethyl group, hydroxyethyl group, hydroxyalkyl group such as hydroxypropyl group, hydroxyethoxyethyl group, hydroxyethoxyethoxyethyl group etc. Examples thereof include an alkoxy polyether group such as a hydroxypolyether group, a methoxyethoxyethyl group, an ethoxyethoxyethyl group, a propoxyethoxyethyl group, and a butoxyethoxyethyl group.

In R ₄ and R ₅ , the alkyl group which may be substituted includes methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl. Group, tert-butyl group, n-
Pentyl group, iso-pentyl group, neopentyl group, n
-Hexyl group, iso-hexyl group, sec-hexyl group, n-heptyl group, iso-heptyl group, sec-heptyl group, n-octyl group, alkyl group such as 2-ethylhexyl group, and halogenoalkyl group such as chloroethyl group ,
Examples thereof include an alkoxyalkyl group such as a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group, a propoxyethyl group, and a butoxyethyl group. Examples of the optionally substituted aryl group include a phenyl group, a naphthyl group, and 4-methylphenyl. Group, 4-ethylphenyl group, 4-propylphenyl group, 4-tert-butylphenyl group, 4-methoxyphenyl group, 4-ethoxyphenyl group, 4-chlorophenyl group, 4-bromophenyl group, 2-methylphenyl Group, 2-ethylphenyl group, 2-propylphenyl group, 2-t-butylphenyl group, 2-methoxyphenyl group, 2-ethoxyphenylthio group, 2-hydroxyphenylthio group, 2-chlorophenyl group, 2-bromo A phenyl group and the like are exemplified, and as the alkylcarbonyl group which may be substituted, Acetyl group, a propionyl group, a butyryl group, iso- butyryl group, valeryl group, iso- valeryl, trimethylacetyl group, a hexanoyl group, t
tert-butylacetyl group, heptanoyl group, octanoyl group, alkylcarbonyl group such as 2-ethylhexanoyl group, cyclopentanecarbonyl group, 6-chlorohexanoyl group, 6-bromohexanoyl group, trifluoroacetyl group, pentafluoro Examples include a propionyl group, a halogenoalkylcarbonyl group such as a perfluorooctanoyl group, an alkoxyalkylcarbonyl group such as a methoxyacetyl group, and the like, and an optionally substituted arylcarbonyl group includes a benzoyl group, an o-chlorobenzoyl group, m-chlorobenzoyl group, p-chlorobenzoyl group, o-fluorobenzoyl group, m-fluorobenzoyl group, p-fluorobenzoyl group, o-acetylbenzoyl group, m-acetylbenzoyl group, p-acetylbenzoyl group, o- Me Kishibenzoiru group, m- methoxybenzoyl group, p- methoxybenzoyl group, o- methylbenzoyl group, m- methylbenzoyl group, p- methylbenzoyl group, o- trifluoromethylbenzoyl group, p
A trifluoromethylbenzoyl group, a pentafluorobenzoyl group, a 4- (trifluoromethyl) benzoyl group, and the like. Examples of the alkylsulfonyl group which may be substituted include a methanesulfonyl group, an ethanesulfonyl group, a propanesulfonyl group, Alkylsulfonyl groups such as butanesulfonyl group, heptanesulfonyl group, hexanesulfonyl group, 2-chloroethanesulfonyl group, 2,
Examples thereof include a halogenoalkylsulfonyl group such as a 2,2-trifluoroethanesulfonyl group and a trifluoromethanesulfonyl group, and a benzylsulfonyl group. Examples of the optionally substituted arylsulfonyl group include a benzenesulfonyl group and an o-chlorobenzenesulfonyl group. M-chlorobenzenesulfonyl group, p-chlorobenzenesulfonyl group, o-fluorobenzenesulfonyl group, m-fluorobenzenesulfonyl group, p-fluorobenzenesulfonyl group, pentafluorobenzenesulfonyl group, o-methoxybenzenesulfonyl group, m-methoxy Benzenesulfonyl group, p-methoxybenzenesulfonyl group, o-
Examples thereof include a methylbenzenesulfonyl group, an m-methylbenzenesulfonyl group, a p-methylbenzenesulfonyl group, a 2-mesitylenesulfonyl group, a 4-tert-butylbenzenesulfonyl group, and an N-acetylsulfanylyl group.

In particular, a near-infrared absorbing agent having a linear or branched alkyl group as R ₁ and R _{2 and a} hydrogen atom, a nitro group or an amino group as R ₃ is preferable.

The divalent metal represented by M is Cu
(II), Zn (II), Fe (II), Co (II), Ni
(II), Ru (II), Rh (II), Pd (II), Pt
(II), Mn (II), Mg (II), Ti (II), Be
(II), Ca (II), Ba (II), Cd (II), Hg
(II), Pb (II), Sn (II) and the like.

As the monosubstituted trivalent metal, Al—Cl,
Al-Br, Al-F, Al-I, Ga-Cl, Ga-
F, Ga-I, Ga-Br, In-Cl, In-Br,
In-I, In-F, Tl-Cl, Tl-Br, Tl-
I, Tl-F, Al- C 6 H 5, Al-C 6 H 4 (C
_{H 3), In-C 6} H 5, In-C 6 H 4 (CH 3), In-
C ₆ H ₅ , Mn (OH), Mn (OC ₆ H ₅ ), Mn [OS
i (CH ₃ ) ₃ ], Fe—Cl, Ru—Cl and the like.

The disubstituted tetravalent metal includes CrCl ₂ ,
SiCl ₂ , SiBr ₂ , SiF ₂ , SiI ₂ , ZrC
l ₂ , GeCl ₂ , GeBr ₂ , GeI ₂ , GeF ₂ , Sn
Cl ₂ , SnBr ₂ , SnF ₂ , TiCl ₂ , TiBr ₂ ,
TiF ₂ , Si (OH) ₂ , Ge (OH) ₂ , Zr (O
H) ₂ , Mn (OH) ₂ , Sn (OH) ₂ , Ti (R) ₂ ,
Cr (R) ₂ , Si (R) ₂ , Sn (R) ₂ , Ge (R) ₂
[R represents an alkyl group, a phenyl group, a naphthyl group, and derivatives thereof], Si (OR ′) ₂ , Sn (O
R ') ₂ , Ge (OR') ₂ , Ti (OR ') ₂ , Cr
(OR ′) ₂ [R ′ represents an alkyl group, a phenyl group, a naphthyl group, a trialkylsilyl group, a dialkylalkoxysilyl group and a derivative thereof], Sn (SR ″) ₂ ,
Ge (SR ″) ₂ [R ″ represents an alkyl group, a phenyl group, a naphthyl group, and derivatives thereof] and the like.

Examples of oxymetals include VO, MnO,
TiO and the like are exemplified.

Particularly preferred M is two hydrogen atoms, N
i, Cu, Zn, Pd, AlCl, InCl, TiO,
VO.

The near-infrared absorbing agent represented by the general formula (1) of the present invention is produced, for example, by reacting a dicyanonaphthalene derivative represented by the following formula (2) with a metal or a metal compound in a solvent. it can. Further, a metal-free near-infrared absorber in which M is two hydrogen atoms is, for example,
It can be produced by reacting a dicyanonaphthalene derivative represented by the following formula (2) in a solvent in the presence of a base. The starting compound (2) is preferably a dicyanonaphthalene derivative in which R ₃ is a hydrogen atom, or a dicyanonaphthalene derivative in which a nitro group is substituted at the 5-position, in terms of availability and ease of synthesis. .

As a specific method for synthesizing a dicyano naphthalene derivative in which a nitro group is substituted at the 5-position, dichloronaphthoquinone is used as a raw material, followed by nitration described in Synthetic Organic Chemistry, Vol. 16, No. 10 (1958), followed by nitration. The Chemical Society of Japan No. 12 (198
The dicyano compound is synthesized by the method described in 1), and the obtained diol is easily alkylated to be easily obtained. A dicyano naphthalene derivative having a nitro group substituted at the 6-position can be obtained in the same manner. A dicyano naphthalene derivative in which R ₃ is a hydrogen atom can be easily obtained by subjecting dichloronaphthoquinone as a raw material to a cyanation or alkylation reaction after the above-mentioned nitration reaction.

[0026]

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(In the formula, R _{1 to} R ₃ have the same meaning as in the general formula (1).) In the general formula (1), a method for producing a near-infrared absorbing agent in which M is a metal or a metal compound will be described. .

As the metal or metal compound, Al,
Si, Ti, V, Mn, Fe, Co, Ni, Cu, Z
n, Ge, Ru, Rh, Pd, In, Sn, Pt, P
b, Mg, Ca, Ba, Be, Cd, Hg and their halides, carboxylate, sulfate, nitrate, carbonyl compound, oxide, complex and the like. In particular, metal halides or carboxylate salts are preferably used,
Examples of these are copper chloride, copper bromide, copper iodide, nickel chloride, nickel bromide, nickel acetate, cobalt chloride, cobalt bromide, cobalt acetate, iron chloride, zinc chloride, zinc bromide, zinc iodide, Zinc acetate, vanadium chloride, vanadium oxytrichloride, palladium chloride, palladium acetate, aluminum chloride, manganese chloride, manganese acetate, manganese acetylacetone, manganese chloride, lead chloride, lead acetate, indium chloride, titanium chloride, tin chloride, etc. .

The amount of the metal or metal compound used is 0.2 to 0.2 with respect to the dicyanonaphthalene derivative of the general formula (2).
It is 0.6 mole, preferably 0.25 to 0.4 mole.

The solvent used for the reaction has a boiling point of 100
An organic solvent having a temperature of at least 130 ° C, preferably at least 130 ° C, is used. Examples include n-amyl alcohol, n-hexanol, cyclohexanol, 2-methyl-1-pentanol, 1-heptanol, 2-heptanol, 1-octanol, 2-ethylhexanol, benzyl alcohol, ethylene glycol, propylene glycol, Alcohol solvents such as ethoxyethanol, propoxyethanol, butoxyethanol, dimethylaminoethanol and diethylaminoethanol, trichlorobenzene, chloronaphthalene, sulfolane, nitrobenzene, quinoline, N, N-dimethylformamide, N-methyl-2
-Pyrrolidone, N, N-dimethylimidazolidinone,
High-boiling solvents such as N, N-dimethylacetamide and urea are exemplified.

The amount of the solvent to be used is 1 to 100 times by weight, preferably 5 to 20 times by weight, relative to the dicyanonaphthalene derivative.

In the reaction, ammonium molybdate or DBU (1,8-diazabicyclo [5.4.0] undecene) may be added as a catalyst. The addition amount is 0.1 to 1 mol of the dicyano naphthalene derivative.
It is 10 mol, preferably 0.5 to 2 mol.

[0033] The reaction temperature is 100 to 300 ° C, preferably 130 to 220 ° C.

In the general formula (1), a method for producing a metal-free near-infrared absorbing agent in which M is two hydrogen atoms will be described.

As the base, DBU (1,8-diazabicyclo [5.4.0] undecene), KOCH ₃ , N
Examples include, but are not limited to, alcoholates of alkali metals such as aOCH ₃ .

The amount of the base used is 0.1 to 2 moles, preferably 0.2 to 0.8 moles, per mol of the dicyanonaphthalene derivative of the general formula (2).

The solvent used in the reaction is a boiling point of 60 ° C.
Or more, preferably 90 ° C. or more, more preferably 130 ° C.
An organic solvent having a temperature of not less than ° C is used. Examples are n-propanol, iso-propanol, n-butanol, is
o-butanol, n-amyl alcohol, n-hexanol, cyclohexanol, 2-methyl-1-pentanol, 1-heptanol, 2-heptanol, 1-octanol, 2-ethylhexanol, benzyl alcohol, ethylene glycol, propylene glycol Alcohol solvents such as ethoxyethanol, propoxyethanol, butoxyethanol, dimethylaminoethanol, diethylaminoethanol, trichlorobenzene, chloronaphthalene, sulfolane, nitrobenzene, quinoline, N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl -2-pyrrolidone, N, N
-High-boiling solvents such as dimethylimidazolidinone and urea.

The amount of the solvent to be used is 1 to 100 times by weight, preferably 5 to 20 times by weight, relative to the dicyanonaphthalene derivative.

In the reaction, ammonium molybdate may be added as a catalyst. The addition amount is 0.01 to 10 mol, preferably 0.1 to 2 mol, per 1 mol of the dicyano naphthalene derivative.

The reaction temperature is 60-250 ° C., preferably 1
The temperature is from 00 to 200C, more preferably from 130 to 180C.

As a post-treatment after completion of the reaction, the target compound can be obtained by distilling off the solvent after the reaction or discharging the reaction solution into a poor solvent for the near-infrared absorbent and filtering the precipitate. Further, a higher purity near-infrared absorbing agent can be obtained by further recrystallization or purification by column chromatography.

Further, the electrophotographic toner of the present invention will be described.

The electrophotographic toner of the present invention comprises at least a binder resin, the above-mentioned near-infrared absorbing agent, and a coloring agent.

The binder resin to be used is not particularly limited, but generally used polymer resins can be used. Examples thereof include polystyrene, a copolymer of styrene and acrylate or methacrylate, and polyester. Resins, epoxy resins, polyamide resins, phenolic resins, hydrocarbon resins, petroleum resins and the like,
These may be used alone or as a mixture.

The near-infrared absorbing agent is as described above, and the amount of addition depends on the flash fixing strength of the toner and the like, but is preferably 0.01 to 50% by weight based on the binder resin. Furthermore, in order to control the fixing strength, other near-infrared absorbing dyes, for example, anthraquinone dyes, cyanine dyes, squarylium dyes, aminium dyes, immonium dyes, nickel dithiol dyes, phthalocyanine dyes, naphthalocyanine A system dye or the like may be added.

The colorant is not particularly limited, but may be a commonly used pigment or dye. For example, in the case of a black toner, carbon black and a nigrosine dye may be used. Examples include quinophthalone dyes, azo dyes, azomethine dyes, anthraquinone dyes, benzidine dyes, quinacridone dyes, rhodamine dyes, quinoimine dyes, xanthene dyes, phthalocyanine dyes, triphenylmethane dyes, and the like. Can be These amounts are determined by the binder resin 10
0.1 to 50 parts by weight with respect to 0 parts by weight is preferred.

Further, as necessary, various plasticizers, mold release agents, ultraviolet absorbers, etc. may be added to the electrophotographic toner for the purpose of adjusting a charge control agent, a fluidity modifier, a thermal property, a physical property and the like. Can also be added.

Examples of the charge control agent include a quaternary ammonium salt, a guanamine derivative, an amine-modified styrene-acryl resin, and a benzothiazole derivative as the positive charge control agent, and a metal complex of alkyl salicylic acid as the negative charge control agent. And polycyclic salicylic acid metal salts, metal complexes of dicarboxylic acids, and the like, whereby the charge can be adjusted. The amount of addition is determined in consideration of conditions such as the chargeability of the resin, the content of the colorant, and the chargeability of other additives.
-5 parts by weight is preferred.

Further, as the fluidity modifier, for example, colloidal silica can be mentioned, and its addition amount is preferably 0.01 to 5 parts by weight based on 1 part by weight of the colored toner resin. Further, a polyolefin-based wax and a natural wax can be used in combination.

The toner can be produced by a known method. For example, a binder resin, a near-infrared absorbing agent, and a coloring agent are melt-kneaded by a kneader for pressure, a roll mill, an extruder, etc., uniformly dispersed, finely pulverized by a pulverizer, a jet mill, etc., and classified by a classifier. Thus, a desired toner can be obtained.

The toner thus produced can be used by any of the known fixing methods such as hot roll, pressure fixing, solvent fixing, and light fixing. Great effect. The electrophotographic toner of the present invention can be mixed with a carrier and used as a two-component developer. Examples of the carrier include a ferrite powder, a fine powder magnetic substance dispersed in a resin, and a resin-coated carrier in which the carrier surface is coated with a resin.

[0052]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. The term “parts” means parts by weight, and in the near-infrared absorbing agent, the substitution position of the substituent R ₃ is 1 or 4, 10 or 13, 19, as shown in the following formula.
Or the position at 22, 28 or 31 position is referred to as α position, and 2 or 3, 11 or 12, 20 or 21,
The case of 9th or 30th position is expressed as β position.

[0053]

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Example 1 Synthesis Example of Near Infrared Absorber (b) 4.0 parts of the following compound (a), 0.3 parts of copper (I) chloride, D
After mixing 1.5 parts of BU and 20 parts of n-amyl alcohol, the mixture was stirred under reflux for 6 hours. After cooling, methanol 100
Then, the precipitate was separated by filtration and purified by column chromatography to obtain 2.8 parts of a near-infrared absorbent (b) in which a nitro group was substituted at the α-position.

[0055]

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[0056]

Embedded image Preparation Method of Toner 95 parts of a binder resin (styrene-acrylic acid copolymer; manufactured by Sanyo Chemical Industries, "Hymer TB-1000F" (trade name)), 10 parts of the above near-infrared absorbing agent (b), and 5 parts of C. I. Pigment Blue 15: 1 (manufactured by Dainippon Ink and Chemicals, Inc., “FASTOGEN Blue 5”).
050 "(trade name)) was roughly pulverized by a ball mill and then finely pulverized by a jet mill pulverizer. After further classification,
20 μm was selected, and 90 parts of carrier iron (“EFV250 / 400” (trade name), manufactured by Nippon Iron Powder Co., Ltd.) were uniformly mixed with 10 parts thereof to obtain a developer. This blue toner was set in a commercially available copying machine, and after recording an unfixed image, it was flash-fixed using a xenon flash lamp. The recorded image obtained from this is transferred to a cellophane tape (Sumitomo 3M
Manufactured by "Scotch Mending Tape" (trade name)), the residual ratio of the recorded image after peeling off the tape was calculated by the following formula, and evaluated as the fixing strength. As a result, the residual rate was 90%
And good fixing strength.

Residual rate (%) = {(image density after tape removal) / (image density before tape removal)} × 100

Example 2 Synthesis Example of Near-Infrared Absorber (c) To 30 parts of n-amyl alcohol, 1.0 part of 28% sodium methylate was added, heated to 130 ° C., and stirred for 30 minutes. After cooling to 30 ° C., 3 parts of the compound (a) was added, and the mixture was heated and stirred under reflux for 7 hours. After cooling, the mixture was discharged into 200 parts of methanol, and the precipitate was separated by filtration and purified by column chromatography to obtain 1 part of a near-infrared absorbent (c) in which a nitro group was substituted at the α-position.

[0059]

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Preparation Method of Toner A toner and a developer were prepared in the same manner as in the preparation method of the toner of Example 1, except that the near-infrared absorbing agent (b) was changed to the near-infrared absorbing agent (c). When a peeling test was performed on the toner thus manufactured in the same manner as in Example 1, the residual ratio was 91%, and the fixing strength was good.

Example 3 Method for Preparing Toner Binder resin (polyester resin; NE-21, manufactured by Kao Corporation)
50 (ART-2009) "(trade name) 1320 copies,
30 parts of the above-mentioned near-infrared absorbing agent (b), coloring agent C.I. I. P
Ignition Yellow 81 (manufactured by Dainippon Ink and Chemicals, Inc., "FASTOGEN SUPER YELL")
“OW GRO” (trade name)) 80 parts, charge control agent (Nippon Kayaku, “Kayacharge N-4” (trade name)) 20 parts,
After melt-kneading 50 parts of wax (manufactured by Sanyo Chemical Co., Ltd., “Viscol 550P” (trade name)), the mixture was roughly pulverized by a ball mill and then finely pulverized by a jet mill pulverizer. After further classification, 1 to 20 μm was selected to prepare a toner. Next, a ferrite carrier ("KBN-100" (trade name) manufactured by Hitachi Metals, Ltd.) was uniformly mixed to obtain a developer. The toner thus produced was subjected to a peeling test in the same manner as in Example 1. As a result, the residual ratio was 87%, and the fixing strength was good.

Example 4 Toner Preparation Method 95 parts of a binder resin (epoxy resin; "Epiclon 1191" (trade name), manufactured by Dainippon Ink Industries, Ltd.), 10 parts of the above near-infrared absorbing agent (b), and a colorant ( Toyo Ink, Li
onol Red CP-A "(trade name), 5 parts, a charge adjusting agent (" Bontron P-5 ", manufactured by Orient Chemical Industries, Ltd.)
1) (trade name) was melt-kneaded, coarsely pulverized with a ball mill, and then finely pulverized with a jet mill pulverizer. After further classification, 1 to 20 μm was selected to prepare a toner. Next, a ferrite carrier ("KBN-10" manufactured by Hitachi Metals, Ltd.)
0 "(trade name)) was uniformly mixed to obtain a developer. The toner thus produced was obtained in the same manner as in Example 1.
When a peeling test was performed, the residual ratio was 90%, and the fixing strength was good.

Examples 5 to 40 In the same manner as in Example 1, except that the near-infrared absorbing agent shown in Table 1 was used instead of the near-infrared absorbing agent (b), the toner and the developer were used. Was prepared and subjected to a peel test. Table 1 shows the results. In a peel test using toners containing all near-infrared absorbers, the residual ratio was high and the fixing strength in flash fixing was excellent.
In the table, in the evaluation of fixability, those having a residual ratio of 80% or more are indicated by “○”.

[0064]

[Table 1]

[0065]

[Table 2]

Comparative Example A toner and a developer were prepared in the same manner as in Example 1 except that the following compound (d) was used, and the fixability was evaluated. As a result, the residual ratio of the recorded image in the tape peeling test was 30%.
The results were as follows, and the fixing strength was lower and the fixing was insufficient as compared with the toner using the near-infrared absorbing agent of the present invention.

[0067]

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[0068]

The near-infrared absorber for electrophotographic toner according to the present invention has excellent properties of light energy absorption and light energy / heat energy conversion efficiency. It can be suitably used for the toner used in the system.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryu Ooi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa F-term in Mitsui Chemicals, Inc. 2H005 AA06 CA25 FB03

Claims (5)

[Claims] 1. A near-infrared absorbent for toner for electrophotography represented by the following general formula (1). Embedded image (Wherein R ₁ and R ₂ are each independently an alkyl group which may be substituted, R ₃ is a hydrogen atom, a nitro group or R ₄ , R
₅ represents a nitrogen atom substituted by ₅ and may be the same or different from each other, and R ₄ and R ₅ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl A group, an optionally substituted alkylcarbonyl group, an optionally substituted arylcarbonyl group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl group, and M represents 2
Hydrogen atom, divalent metal atom, trivalent or tetravalent substituted metal, or oxymetal. ) 2. The near-infrared absorbing agent for an electrophotographic toner according to claim ₁ , wherein R ₁ and R ₂ are a linear or branched alkyl group, and R ₃ is a hydrogen atom, a nitro group or an amino group. 3. M is two hydrogen atoms, Ni, Cu, Z
3. The near-infrared absorbing agent for an electrophotographic toner according to claim 1, which is any one of n, Pd, AlCl, InCl, TiO, and VO. 4. An electrophotographic toner comprising the near-infrared absorbing agent for an electrophotographic toner according to claim 1. 5. The electrophotographic toner according to claim 4, wherein the toner is for flash fixing electrophotography.