JP2001109198A - Method for formation of full color image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a color image which gives excellent balance in the gloss between a color image and a black image, good electrification characteristics of the toner, good image characteristics such as image density and fog, stable and good durability characteristics even for continuous printing and good fixing property in thermal fixing and which shows an excellent effect. SOLUTION: The method of forming a full-color image has the following features. Each of three primary color toners and a black toner contains a binder resin, polyethylene wax, coloring agent and electrification controlling agent. All softening temperature the cyan toner, magenta toner and yellow toner are lower than the softening temperature of the black toner. All of the number average mol.wt. of the polyethylene wax in the cyan toner, of the polyethylene wax in the magenta toner and of the polyethylene wax of the yellow toner are lower than the number average mol.wt. of the polyethylene wax in the black toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming an electrostatic image in electrophotography, electrostatic charge recording, electrostatic printing, etc., and more particularly, to a method for forming a three primary color toner of cyan, magenta and yellow and a black toner. The present invention relates to a full-color image forming method for forming a multicolor image by using the method.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
No. 221776, No. 2297691, No. 2357
As described in the specification such as 809, the photoconductive insulating layer is uniformly charged (charging step), and then the layer is exposed (exposure step) to dissipate the charge in the exposed portion. An electrostatic latent image is formed thereon, and a colored charged fine powder called toner is made to adhere to the electrostatic latent image so as to be visualized (development step). After the image is transferred onto a transfer material (transfer step), the image is permanently fixed by heating, pressure or other appropriate means (fixing step). After the transfer of the toner image, the residual toner on the photoconductor is scraped off to clean the photoconductor surface (cleaning step). Also, a full-color electrophotographic method for obtaining a multicolor image of color is disclosed in US Pat. No. 2,962,374.
At least, the image is separated into three primary color signals of cyan, magenta and yellow and exposed, and the above process is performed at least a plurality of times using process colors such as cyan, magenta and yellow. This is to repeatedly develop and obtain a multicolor image in which toner images are superimposed.

In recent years, optical information processing such as masking processing and UCR processing (under color removal), which has been difficult with the conventional analog system, has been made easier by adopting the digital system. Conventionally, a portion expressing black by superimposing three primary color toners of cyan, magenta and yellow can be replaced by the black toner alone, so that the gray balance of the image is improved and the thickness of the toner layer is reduced. This is advantageous in terms of cost and image curl development during fixing. Therefore, as a recent full-color toner, a four-color toner obtained by adding a black toner to three primary colors of cyan, magenta, and yellow is used, but another color toner may be added as necessary. .

As a method of forming a full-color image using an electrophotographic method, various known methods can be used. For example, a toner image formed on a photoreceptor is wound around a transfer drum for each color. Intermediate transfer in which four color toner images are superimposed on an intermediate transfer body such as a transfer drum system, a belt shape, a drum shape, etc., which is transferred onto recording paper and four colors are superimposed on the recording paper, and then transferred onto recording paper in four colors There are a tandem system that has a photoconductor and a developing unit for each of the four colors and sequentially superimposes four colors on recording paper in one pass, and a multiple transfer system that superimposes four colors on the photoconductor and then transfers it to recording paper. . On the other hand, in digital full-color copying machines, printers, and the like, black and white images are still mainly used in general office applications, and so-called matte-tone toners having low image surface gloss are preferred as the black toner. In addition, high-quality glossy images are preferred for full-color images such as presentations and photographs.
It is desired that the image on the sheet has good light transmittance.

[0005] In particular, miniaturized digital full-color printers, which have been actively developed in recent years, are disclosed in US Pat. Nos. 2,895,847 and 3152012, Japanese Patent Publication Nos. 41-9475 and 45-2877.
And non-magnetic one-component developing methods described in Japanese Patent Application Laid-Open Nos. 54-3624 and tandem method have attracted attention as a full-color image forming method corresponding to high speed. As the size and speed of printers are reduced, the size of developing devices, photoconductors, fixing devices, and the like is reduced, and the process speed tends to increase. Therefore, in the developing device, the charge application to the toner is reduced, the charge rising property is deteriorated, the toner fog on the photoreceptor is increased, the white background fog of the printed matter is generated, and the toner charge amount is reduced, so that the image is reduced. If the density is too high, the toner consumption may be deteriorated. Further, in the fixing device, the fixing member is reduced in size and the paper passing speed is increased, so that the fixing strength is lowered, and the fixing property is deteriorated, such as a phenomenon in which the paper is curled and wrapped around the fixing roll.

[0006] To improve these, Japanese Patent No. 284133 is disclosed.
No. 2 proposes to make the viscoelasticity of the three primary color toners different from that of the black toner, and Japanese Patent No. 2768181 proposes to make the amount of fixing heat different between black and white image formation and color image formation. Japanese Patent Application Laid-Open No. Hei 8-23491 proposes that the softening point and the like of a color toner and a black toner are different. Examples of adding a wax include, for example, Japanese Patent Application Laid-Open Nos. 49-65231 and 49-65231. 58-1625
0, JP-A-50-27546, JP-A-55-153
No. 944, JP-A-9-73187 and the like have proposed the addition of a polyolefin wax such as polypropylene or polyethylene, but this has not been sufficient yet.

[0007]

Accordingly, the first aspect of the present invention is as follows.
The purpose of the present invention is to provide a sufficient charge imparting effect to the toner with a small developing device, a sufficient amount of charge can be secured by quickly charging, and unnecessary toner fog on the photoreceptor is reduced,
It is an object of the present invention to provide a full-color image forming method in which a printed matter does not have a stain on a white background portion and has good uniformity of a solid image. A second object of the present invention is to provide a full-color image forming method which has good durability when continuous printing is performed by a printer or the like, and stabilizes image characteristics such as image density and fog and toner consumption. A third object is to provide a full-color image forming method in which a black image has a matte tone with a low gloss and a multicolor image has a high gloss and has good light transparency. A fourth object of the present invention is to provide a full-color image forming method which is free from offset and curl phenomena and has good fixing performance such as sufficient fixing strength by heat fixing with a heating roll or the like.

[0008]

Means for Solving the Problems As a result of intensive studies in view of the above circumstances, the present inventors have found that the softening point of the color toner and that of the black toner and the melting point of the polyolefin wax are different from each other. Solve the problem,
In addition, they have found that they exhibit excellent characteristics, and have completed the present invention. That is, the gist of the present invention is to provide a full-color image forming method for forming a color image using a plurality of color toners and a black toner, wherein the plurality of color toners and the black toner are at least a binder resin, polyethylene wax, a colorant, and The softening temperature of the plurality of color toners containing a charge control agent is lower than the softening temperature of the black toner, and the number average molecular weight of the polyethylene wax in the plurality of color toners is all that of the polyethylene wax in the black toner. A full-color image forming method characterized by having a molecular weight smaller than the number average molecular weight.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The toner particles used in the present invention are a fine powder containing a polyester resin, a colorant, and a negatively chargeable charge control agent, and a dispersion-containing fine powder containing other additives as necessary.
The average particle size of the toner particles is 4 to 20 μm, preferably 4 to 1 μm.
2 μm. The particle size of the toner can be measured, for example, using a Coulter Counter manufactured by Coruter Co., Ltd., Multisizer, or the like.

As the binder resin used in the present invention, various known styrene / acrylic resins, polyester resins, epoxy resins and urethane resins suitable for toners can be used, and particularly linear or non-linear polyester resins. Is preferred. Further, it is preferable that the binder resin for the three-color primary color toner is a linear or non-linear polyester resin and the binder resin for the black toner is a non-linear polyester resin. More preferably, the three-primary color polyester resin tetrahydrofuran (hereinafter, THF) is used. It is preferable that the insoluble content is smaller than the insoluble content of the black polyester resin. Polyester resin is excellent in terms of both mechanical strength and fixability, especially when used as a non-magnetic one-component toner. Non-linear polyester resin for black toner containing THF-insoluble component has low gloss. Preferably, the polyester resin for the three primary colors is a linear resin containing no THF-insoluble matter or a non-linear polyester resin containing a small amount of THF-insoluble matter because of its high gloss. It is to be noted that linear and non-linear polyester resins may be mixed and used for the three color primary color toners and the black toner polyester resin, and by adjusting the mixing ratio thereof, the toner molecular weight, the softening point, and the like can be adjusted within a suitable range. Can be controlled freely.

The polyester resin is composed of a polyhydric alcohol and a polybasic acid. If necessary, at least one of the polyhydric alcohol and the polybasic acid contains a trifunctional or higher polyfunctional component (crosslinking component). It is obtained by polymerizing the product. In the above, examples of the dihydric alcohol used for the synthesis of the polyester resin include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
3-propylene glycol, 1,4-butanediol,
Neopentyl glycol, 1,4-butenediol,
Diols such as 1,5-pentanediol and 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A,
Examples thereof include bisphenol A alkylene oxide adducts such as polyoxypropylene-modified bisphenol A, and the like. Among these monomers, it is particularly preferable to use a bisphenol A alkylene oxide adduct as a main component monomer, and particularly preferably an adduct having an average number of addition of 2 to 7 alkylene oxides per molecule.

Examples of the trihydric or higher polyhydric alcohol involved in the crosslinking of polyester include sorbitol and
1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol , 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and the like.

On the other hand, polybasic acids include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid Examples thereof include acids, malonic acids, anhydrides of these acids, lower alkyl esters, alkenylsuccinic acids or alkylsuccinic acids such as n-dodecenylsuccinic acid and n-dodecylsuccinic acid, and other divalent organic acids. Examples of tribasic or higher polybasic acids involved in the crosslinking of polyester include 1,2,4-
Benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,2
4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetra Carboxylic acids, their anhydrides, and others can be mentioned.

These polyester resins can be synthesized by an ordinary method. Specifically, the reaction temperature (1
Conditions such as 70 to 250 ° C.) and reaction pressure (5 mmHg to normal pressure) may be determined according to the reactivity of the monomer, and the reaction may be terminated when predetermined physical properties are obtained. The softening temperature (Sp) of these polyester resins is 80 to
The temperature is 160 ° C, and among them, the one at 90 to 150 ° C is more preferable. The glass transition temperature (Tg) is
The temperature is 50 to 75 ° C, and among them, the one having a temperature of 55 to 70 ° C is more preferable. In this case, when Sp is lower than the above range, an offset phenomenon at the time of fixing is likely to occur, and when Sp is higher than the above range, fixing energy increases, and glossiness and transparency tend to deteriorate with color toner, which is not preferable. . When the Tg is lower than the above range, the toner tends to aggregate and fix, and when the Tg is higher than the above range, the fixing strength at the time of thermal fixing tends to decrease, which is not preferable. S
p can be controlled mainly by the molecular weight of the resin, and the number average molecular weight is preferably 2,000 to 20,000, more preferably 3,000 to 12,000. The Tg can be adjusted mainly by selecting a monomer component constituting the resin. Specifically, the Tg can be increased by using an aromatic polybasic acid as a main component as an acid component. That is, among the above-mentioned polybasic acids, phthalic acid, isophthalic acid, terephthalic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid and the like, and anhydrides and lower alkyl esters thereof are used. It is desirable to use it as a main component.

THF-insoluble content of polyester resin (%)
Is obtained by extracting the resin sample (W ₁ ) with THF using a Soxhlet extractor for 6 hours and then weighing (W ₂ ) the remaining amount without being extracted after drying, and obtaining the formula (W ₂ /
W ₁ ) × 100 (%). Sp of the polyester resin was measured using a flow tester described in JIS K7210 and K6719. Using a flow tester (CFT-500, manufactured by Shimadzu Corporation), about 1 g of a sample was heated at a rate of 3 ° C./min. 1c while heating with
A load of 30 kg / cm ² was applied by a plunger of m ² , extruded from a die having a hole diameter of 1 mm and a height of 10 mm, and a temperature corresponding to an intermediate point between a descent start temperature and a descent end temperature of the plunger was defined as a softening temperature. is there. The Tg was measured using a differential scanning calorimeter (DSC) at a heating rate of 10
The measurement was performed at a temperature of ° C./min, and a temperature corresponding to an intersection where a tangent line was drawn at the inflection point (shoulder).

On the other hand, if the acid value of the polyester resin is too high, it is generally difficult to obtain a stable and high charge amount, and the charge stability at high temperature and high humidity tends to be deteriorated. The value is 30 KOHmg / g
It is better to be less than 25KOHmg /
g. As a method for adjusting the acid value within the above range, other than a method of controlling the addition ratio of the alcohol-based and acid-based monomers used in the resin synthesis, for example, the acid monomer component is previously converted to a lower alkyl ester by a transesterification method. And a method of neutralizing residual acid groups by adding a basic component such as an amino group-containing glycol to the composition, but not limited thereto. Needless to say, it can be adopted. In addition,
The acid value and hydroxyl value of the polyester resin are determined according to JIS K00.
It is measured according to the method of No. 70. However, when the resin is difficult to dissolve in the solvent, a good solvent such as dioxane may be used.

Among these polyester resins, resins having different components from among known polyester resins may be used alone or in combination of two or more, or resins having different viscoelastic properties and thermal properties such as different molecular weight distributions among resins of the same kind may be used. You may use individually or in combination of 2 or more types. Known resins such as styrene resins, styrene-acrylic copolymer resins, epoxy resins, and urethane resins other than polyester resins may be used in combination.
It is preferably at least 0% by weight.

Next, the polyethylene wax used in the present invention will be described. In the present specification, the polyethylene wax includes, in addition to pure polyethylene, a commercially available polyethylene wax, commonly referred to as a polyethylene wax, such as an ethylene-propylene copolymer (ethylene is 51% by weight or more) and And copolymers of ethylene and other olefins, including oxidized and modified types. In the present invention, other polyolefin waxes can be used in addition to the polyethylene wax.

Examples of the polyolefin wax other than polyethylene used in the present invention include polypropylene, polybutene, polyhexene, ethylene-butene copolymer and the like. The melting points of polyethylene and other polyolefin waxes used in the present invention are 70 to 180.
C is preferable, and 80 to 160 C is more preferable. 180
If the melting point is higher than ℃, the polyolefin will not be sufficiently melted even when heated during production with a toner kneader, etc., and the compatibility and dispersibility in the resin will tend to be poor, and the minimum fixing temperature of the toner will deteriorate. Tend to. On the other hand, when the melting point is lower than 70 ° C., the toner is not easily sheared when produced by a toner kneader or the like, and the dispersibility of the colorant and other internal additives tends to deteriorate. The melting point of polyethylene wax is 8
Those having a temperature of 0 to 150 ° C are particularly preferred.

In the present invention, when polyethylene wax and another polyolefin wax are used in combination, the polyethylene wax is used in an amount of 5 to 5% of the total wax.
It is preferably at least 0% by weight, more preferably at least 65%. The polyolefin wax used in combination with the polyethylene wax has a melting point of 90-17.
0 ° C. polypropylene wax is particularly preferred. The number average molecular weight (Mn) of the polyethylene wax is 10
00 to 10000 is preferable, and 1000 to 7000 is more preferable. When the polyolefin wax used in combination is a polypropylene wax, the number average molecular weight is 200.
0-10000 is preferred. When the Mn is significantly lower than the above range, the filming phenomenon on the photoconductor and the developing member tends to occur easily, and when the Mn is extremely high, the one-component charging characteristic is inferior, and the fog on the photoconductor and the white background stain on plain paper are reduced. The improvement effect tends to be hardly exhibited.

The molecular weight of the polyolefin wax is determined by high-temperature gel permission chromatography (hereinafter referred to as
GPC), and there are some differences depending on the measurement conditions. For example, the measurement can be performed under the following conditions. That is, at a temperature of 135 ° C.,
Using dichlorobenzene (added with 0.1% ionomer), flow at a flow rate of 1 ml / min, and inject 400 μl of a 0.1% by weight sample solution to measure. In measuring the molecular weight of the sample, a value in terms of polystyrene is used from a calibration curve prepared using a monodisperse polystyrene standard sample. The column to be used is not limited at all, but for example, A-80M manufactured by Shodex Co., Ltd. is used.

The melting point of the polyolefin wax is determined from an endothermic pattern of thermal analysis (differential thermal analyzer, differential scanning calorimeter, etc.), and the peak position temperature is defined as the melting point. The added amount of polyethylene wax is preferably 0.1 to 6 parts by weight, more preferably 0.1 to 6 parts by weight, based on 100 parts by weight of the binder resin.
It is in the range of 2 to 5 parts by weight. If the addition amount is less than 0.1 part by weight, fogging on the photoreceptor or white paper stain of plain paper deteriorates, which is not preferable. If it exceeds 6 parts by weight, a filming phenomenon on the photoreceptor and the developing member is liable to occur. Poor transportability due to poor fluidity is likely to occur, which is not preferable.

In the toner used in the present invention, cyan
Among the polyethylene wax contained in the magenta yellow primary color toner and the polyethylene wax contained in the black toner, the number average molecular weight (Mnc) of the polyethylene wax contained in the cyan toner, the number average molecular weight of the polyethylene wax contained in the magenta toner ( Mn
m) and the number average molecular weight (Mny) of the polyethylene wax contained in the yellow toner are both the number average molecular weight (Mn) of the polyethylene wax contained in the black toner.
It is a requirement that it be lower than nb).

As the colorant used in the black toner of the present invention, various known dyes and pigments such as carbon black, magnetite and aniline black can be used. When used in a magnetic toner, magnetite is preferred. Particularly, when used in a non-magnetic one-component negatively chargeable toner, acidic carbon black is preferred. The term “acidic” means that the value obtained by measuring the pH of a suspension obtained by boiling carbon black and pure water is 6%. Refers to the following, more preferably 5
The following are preferred. If the carbon black is other than the acidic carbon black, the chargeability of the negative charge is not improved, which is not preferable. Further, the carbon black of the present invention is preferably produced by a furnace method. The carbon black preferably has a specific surface area of 20 to 500 m ² / g by adsorption of nitrogen by the BET method and a dibutyl phthalate (DBP) oil absorption of about 30 to 150 ml / 100 g. BET specific surface area is 20m
² / g smaller than particles become too dispersibility of carbon black is deteriorated greatly, also 500m ² / g higher than the share when the particles are kneaded finely - become poor dispersion of consuming less likely to be carbon black.

The carbur black may be subjected to a surface treatment with a metal soap or the like, if necessary, for the purpose of surface modification.
At the time of use, untreated and surface-treated ones may be used in combination. As the coloring material of the three primary colors (cyan, magenta, and yellow) toners of the present invention, various known dyes and pigments can be used, and the following are listed as examples. As the yellow toner, C.I. I. Pigment Yellow 1, 3, 74, 97, 98
Acetoacetic acid arylamide monoazo yellow pigments such as
C. I. Pigment Yellow 12, 13 and 14,
Azoacetate arylamide-based disazo yellow pigments such as those described in No. 17; I. Condensed monoazo yellow pigments such as CI Pigment Yellow 93 and 155; I. Other yellow pigments such as CI Pigment Yellow 180, 150 and 185;
C. I. Solvent Yellow 19, 77, 79
C. I. Examples include yellow dyes such as Disperse Yellow 164. As magenta toner, C.I. I. Pigment Red 48, 49: 1, 53: 1, 5
7, the same 57: 1, the same 81, the same 122, the same 5, the same 146,
184, 238; C.I. I. Red or red pigments such as CI Pigment Violet 19; I. Red dyes such as Solvent Red 49, 52, 58, and 8 can be exemplified. As the cyan toner, C.I. I. Pigment Blue 15: 3, 15: 4, etc., blue colourants of copper phthalocyanine and derivatives thereof; I. Pigment Green 7, 36 (phthalocyanine green)
And other green pigments.

Of these, cyan toner has C.I. I.
Pigment Blue 15: 3 and 15: 4 blue pigments are preferred. For magenta toner, magenta: C.I. I. Pigment Red 57: 1, 122, 146, 1
Red and red pigments of Pigment Violet 84, Pigment Violet 238 and Pigment Violet 19 are preferable. I. Pigment Yellow 13, 1
7, 74, 93, 150, 155, 180,
185 yellow pigments are preferred. These colorants for color may be used alone or in combination of two or more.
The amount of the colorant to be used is preferably about 1 to 15 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the binder resin.

In the toner of the present invention, it is preferable to use a charge control agent for imparting more charge. As the charge control agent for the negatively chargeable toner, a chromium azo complex dye, an iron azo complex dye, a cobalt azo complex dye, Chromium-zinc-aluminum-boron complex or salt compound of salicylic acid or a derivative thereof, chromium-zinc aluminum-boron complex or salt compound of naphtholic acid or a derivative thereof,
Chromium / zinc / aluminum / boron complex or salt compound of benzylic acid or its derivative, long-chain alkyl.
Surfactants such as carboxylate and long-chain alkyl sulfonate are used as charge control agents for positively charged toners.
Nigrosine dyes and derivatives thereof, derivatives such as triphenylmethane derivatives, quaternary ammonium salts, quaternary phosphonium salts, quaternary pyridinium salts, guanidine salts, amidine salts and the like are exemplified. These charge control agents may be used alone or in combination of two or more. However, as the charge control agent used in the three primary color toners, those which are colorless and have a color as light as possible without affecting the color tone are preferable. Further, as the charge control agent, a negatively chargeable charge control agent is preferable because the effect of the present invention can be effectively exhibited.

The charge control agent in the present invention is a boron-based charge control agent, particularly a compound represented by the following general formula [I], as a charge control agent for cyan, magenta and yellow toners. An azo metal compound is advantageously used as the charge control agent.

[0029]

Embedded image

(Wherein, R _{1 to} R ₄ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and X ⁺ represents a cation). R _{1 to} R ₄ represent a hydrocarbon group which may be substituted, and specific examples of the hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propylene group, and an isopropyl group. , Cyclohexyl group, cycloalkyl group such as cyclopentyl group, vinyl group, alkenyl group such as allyl group,
And aromatic hydrocarbon groups such as phenyl and naphthyl groups. These hydrocarbons may be substituted, but the substituent is preferably a halogen atom, a hydroxyl group, a sialic group, an alkyl group, an alkenyl group, or an alkoxy group. It is preferable that at least two of R _{1 to} R ₄ are aromatic hydrocarbon groups and X ⁺ is an alkali metal ion. Further, as a commercially available product, LR-147 manufactured by Nippon Carlit Co., Ltd. is known. Compound, that is, R ₁
It is particularly preferred that all R ₄ are phenyl groups and X ⁺ is a potassium ion. The addition amount of the charge control agent of the boron compound is preferably 0.05 to 8 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the binder resin.
1-5 weight parts is good.

The metal component of the azo-based metal compound used as the charge control agent for the black toner is preferably chromium or iron. The addition amount of the charge control agent of these azo-based metal compounds may be 0.0 to 100 parts by weight of the binder resin.
It is preferably 5 to 10 parts by weight, more preferably 0.1 to 6 parts by weight.

The chromium-azo compound used in the present invention is preferably a compound represented by the following general formula [II], and commercially available compounds include, for example, Bontron S manufactured by Orient Chemical Industries, Ltd. -34, S-54, T-95 manufactured by Hodogaya Chemical Co., and the like are known.

[0033]

Embedded image

(Wherein, A to D may be the same or different and represent an optionally substituted benzene ring.
X ⁺ represents a cation. In the general formula [II], the substituent of the benzene ring of A to D is preferably an alkyl group, a halogen atom, a cyano group, a nitro group, a hydroxyl group, or an alkoxy group, and more preferably a chlorine atom. X ⁺ represents a cation, and is preferably a hydrogen ion, an alkali metal ion, or an ammonium ion.

As the iron / azo compound used in the present invention, a compound represented by the following general formula [III] is preferable. -77 and the like are known.

[0036]

Embedded image

(Wherein, E to J may be the same or different and each represents an optionally substituted benzene ring.
X ⁺ represents a cation. In the general formula [III], when the benzene ring of E to J has a substituent, the substituent may be a halogen atom, a sulfonamide group, a mesyl group, a sulfonic group, a hydroxyl group, an amino group, an alkoxycarbonyl group. A acetylamino group, a benzoylamino group, a hydrocarbon group which may be substituted, an alkoxy group which may be substituted, and the substituent is an alkyl group, an alkenyl group, a halogen atom,
A cyano group, a hydroxyl group, an amino group and a nitro group are preferred, a halogen atom and an alkoxy group are more preferred, and a chlorine atom,
A methoxy group is particularly preferred. X + represents a cationic group, preferably a hydrogen ion, an alkali metal ion, or an ammonium ion, and more preferably a sodium ion or a potassium ion.

In order to improve the dispersibility and compatibility in the toner, the colorant and the charge controlling agent are preliminarily dispersed by pre-kneading with a resin, so-called master batch treatment, or the pigment dispersion after the pigment formation reaction. A high-concentration pigment dispersion treatment, that is, a so-called flushing treatment may be performed by adding a resin to the liquid and replacing and mixing the resin with the dispersion medium at the time of pigment production. By dispersing the pigment particle diameter in these processed products to about half wavelength (200 nm) of visible light, transparency of a color image and the like can be made advantageous. Further, the particle size of the treated product itself is preferably the same as the particle size of the binder resin. If the particle size is too large, the colorant in the toner tends to be unevenly distributed during continuous production. In general, the particle size of the master batch-treated product and the flushing-processed product is preferably one that has passed through a sieve having an opening of 3 mm, and preferably has passed a sieve having an opening of 2 mm or less. In the present invention, various known organic or inorganic fine particle powders may be used as additives for the purpose of improving the adhesiveness, cohesiveness, fluidity, chargeability, surface resistance and the like of the toner.

As the fine powder to be added to the toner surface, so-called external additive, an inorganic fine powder surface-treated with at least a silane coupling agent and silicone oil is preferable. These surface treatment agents add hydrophobicity, fluidity, and chargeability to the inorganic fine powder, so that the non-magnetic one-component toner has good negative charge buildup and good charge characteristics can be obtained. As the core of the inorganic fine powder, silica, titania, alumina, zinc oxide, magnesium oxide, magnetite, ferrite, and the like, which can be used by a known wet or dry method, can be used, but silica, titania, and alumina are preferably used. And more preferably silica.

In the case of a non-magnetic one-component toner, one kind of inorganic fine powder may be used.
It is preferable to use more than one kind in combination. In particular, when two or more inorganic fine powders are used together in a non-magnetic one-component negatively chargeable toner, at least a relatively coarse inorganic fine powder (a) and a relatively fine inorganic fine powder (b) are used. One of the inorganic fine powders may be surface-treated with silicone oil. The coarse inorganic fine powder (a) has a specific surface area of 80 m ² by the BET method.
/ G is preferably less than 5 to 79 m ² / g.
And the size of the fine inorganic fine powder (b) is BE.
T method specific surface area of 80 m ² / g or more, more preferably is suitable 80~500m ² / g. Further, it is more preferable that the surface treating agent of the inorganic fine powder (a) is silicon oil and the surface treating agent of the inorganic fine powder (b) is silicone oil or a coupling agent.

The relatively coarse inorganic powder (a) improves the anti-blocking property of the toner, suppresses agglomeration of the toner particles in the developing tank, suppresses the pulverization of the toner by mechanical impact relaxation, and reduces the use of external additives. It is estimated that there are effects such as suppression of embedding, prevention of filming of the toner component on the photoconductor, and suppression of the phenomenon of adhesion to the toner layer thickness regulating member. These effects provide excellent storage stability and continuous printing. , The durability performance is improved, for example, the image deterioration and the in-machine contamination due to toner scattering and leakage hardly occur. BET specific surface area is 80m ²
/ G or more, the role of the inorganic fine powder (a) as a partition wall between the toner and the developing tank member is hardly exhibited,
Blocking resistance tends to deteriorate, and durability performance during continuous printing tends to deteriorate. The use of silicone oil as a surface treatment agent for the inorganic fine powder (a) is preferable because it imparts a hydrophobizing function to improve environmental dependency and does not easily inhibit the chargeability of the toner. In the case of the inorganic fine powder (a) treated with silicon oil, the charge rise of the negatively charged toner is improved, and the fog on the photoreceptor and the fog on the plain paper white background are improved. Surface treatment agents other than silicone oil tend to inhibit the charging characteristics of the toner.

It is presumed that the relatively fine inorganic fine powder (b) has the effects of improving the fluidity of the toner and the transportability of the toner in the developing tank. Is excellent, the toner layer in the developing section is uniform,
A high quality printed matter such as a dense, uniform and good image portion can be obtained. When the BET specific surface area is less than 80 m ² / g, the effect of improving the fluidity of the inorganic fine powder (b) in the toner is weakened, and the toner replenishing property is deteriorated, so that a high-quality printed matter tends not to be obtained. As a surface treating agent for the inorganic fine powder (b), a hydrophobic function using a silane coupling agent or silicone oil is imparted to improve the environmental dependence and to be excellent in the fluidity improving function of the inorganic fine powder. .
Surface treatment agents other than silane coupling agents or silicone oils tend to have poor fluidity improving functions.

The cores of the inorganic fine powder (a) and the inorganic fine powder (b) may be of the same type or different types. A conventionally known method is used for the surface treatment of the inorganic fine powder with silicone oil. For example, as silicone oil, dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, and modified silicon which are common straight silicone oils are used. Oils include methacrylic acid-modified silicone oil, epoxy-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, amino-modified silicone oil, etc.
It is used in one kind or in a mixture of two or more kinds. Preferably, the silicone oil is a straight silicone oil, of which dimethyl silicone oil is preferred.

The surface treatment of the inorganic fine powder with a silane coupling agent may be carried out by a conventionally known method. For example, organosilanes such as methoxytrimethylsilane, dimethoxyalkoxylan, trimethoxymethylsilane, ethoxytrimethyl may be used as the silane coupling agent. Silanes), organochlorosilanes (trichloromethylsilane, dichlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, dichlorodiethylsilane, chlorotriethylsilane, trichlorophenylsilane, etc.), and organosilazanes (triethylsilazane, tripropylsilazane) , Triphenylsilazane, hexamethyldisilazane, hexaethyldisilazane, hexaphenyldisilazane, etc.), organodisilazane, organosilane and the like. Used in the seed or in combination of two or more. Preferred as the silane coupling agent are organochlorosilane and organosilazane.
Alternatively, the surface treatment of the silicon oil may be performed after the treatment with the silane coupling agent, or the surface treatment of the silicon oil may be used in combination with the silane coupling agent.

The BET specific surface area of the inorganic fine powder can be measured using a commercially available BET specific surface area measuring apparatus by nitrogen adsorption. For example, a fluid type specific surface area automatic measuring apparatus manufactured by Shimadzu Corporation. (Flow soap 2300
Shape). The average particle size of the inorganic fine powder may be determined by measuring the particle size from an image taken at a high magnification (for example, 50,000 or more) at which the particles can be identified with a transmission electron microscope.

The amount by weight (W ₀ ) of the inorganic fine powder added as an external additive is preferably 20 to 400%, more preferably 30 to 300%, when the toner particles are 100 parts by weight.
% Is preferred. When used in combination of two or inorganic fine powder of the total added weight sum of added parts by weight (W _b) of the added parts by weight (W _a) and fine inorganic fine powder (b) of coarse inorganic fine powder (a) The unit may be W ₀ . The total added parts by weight (W ₀ )
When the amount is less than this range, the original effect of the inorganic fine powder is not exerted, which is not preferable, and when the amount is too large, filming of the photoreceptor easily occurs, fogging on the photoreceptor, and fog on plain paper white background are easily deteriorated. It is not preferable because it is easy to cause. Furthermore, the addition weight of the added weight of the inorganic fine powder _(a) (W a) and inorganic fine powder _(b) (W b) is, W _a is W _b
Preferably can be exhibited strongly relatively coarse inorganic fine powder effect greater it is non-magnetic one-component toner, or more preferably W _a is at 0.2 part by weight versatile than W _b. As the added parts by weight of the inorganic fine powder (a) and the inorganic fine powder (b), the coverage f of each is calculated independently, and the coverage is f ≦ 300, preferably f ≦ 200. If it is more than this, it is difficult to exert the respective effects of the inorganic fine powders (a) and (b), and it tends to cause image defects and the like. The coverage f when one type of inorganic fine powder is mixed with the toner particles is calculated by the following formula [F1].

[0047]

(Equation 1)

In the formula [F1], f is the coverage (%), D
_t is the volume average particle diameter (μm) of the toner particles, d _a and d ₀ are the average particle diameters (μm) of the inorganic fine powder, and ρ _t and ρ ₀ are the true specific gravities of the toner particles and the inorganic fine powder. The coverage f when two types of inorganic fine powders (a) and (b) are mixed with the toner particles is calculated by the following formula [F2].

[0049]

(Equation 2)

In the formula [F2], f is the coverage (%), D
The volume average particle diameter of _t the toner particles _{(μm), d a, d} b are respectively the average particle diameter of the inorganic fine powder (a), the inorganic fine powder (b) (μm), ρ t, ρ a, ρ b Is the true specific gravity of each of the toner particles, the inorganic fine powder (a) and the inorganic fine powder (b). As other external additives of the toner, various known organic and inorganic fine particles for the purpose of a resistance adjusting agent, an abrasive, a charge adjusting agent, and the like, for example, fluorine-based resin powders such as polyvinylidene fluoride and polytetrafluoroethylene. , Zinc stearate, fatty acid metal salts such as calcium stearate, resin beads mainly containing polymethyl methacrylate or silicone resin, minerals such as talc, hydrotalcite, ferroelectric fine powder such as strontium titanate, Examples include conductive fine powder such as conductive titania. These amounts are preferably from 0.01 to 10 parts by weight based on 100 parts by weight of the toner particles.

The toner used in the present invention can be produced by various production methods including conventionally known methods, and the following examples are given as general production methods. (1) A resin, a charge control substance, a colorant, and additives to be added as needed are uniformly dispersed in a mixing apparatus having a rotating section such as a blade or a screw. As the mixing apparatus, a Henschel mixer manufactured by Mitsui Mining Co., a Ladige mixer manufactured by Matsubo, a Nauta mixer manufactured by Hosokawa Micron, a super mixer manufactured by Kawata, or a general V-type mixer in which the container itself rotates can be used. .

(2) The dispersion is melt-kneaded with a kneader, extruder, roll mill or the like. Examples of the kneading apparatus include continuous extruders such as a ZSP extruder manufactured by W & P, a co-kneader manufactured by BUSS, a TEM extruder manufactured by Toshiba Machine Co., a PCM extruder manufactured by Ikegai, and a Nidex manufactured by Mitsui Mining Co., Ltd. A general batch-type kneader can also be used. As a cooling device after the kneading, a drum cooler manufactured by Mitsui Mining Co./Mitsubishi Chemical Engineering Co., Ltd., a belt cooler manufactured by NBC Co., etc. can be used. (3) The kneaded material is coarsely pulverized by a coarse pulverizer and then finely pulverized by a fine pulverizer. Examples of the pulverizer include jet mills such as an I / IDS type jet mill manufactured by NPK and AFG / TJM manufactured by Hosokawa Micron;
The particles are pulverized stepwise to a predetermined toner particle size using an impact type pulverizer such as an ACM pulperizer, a turbo mill manufactured by Turbo Industries, a KTM manufactured by Kawasaki Heavy Industries, a super rotor manufactured by Nisshin Engineering, and a fine mill manufactured by NPK.

(4) The finely pulverized material is classified by a classifier. As a classifier, an air flow classifier having a rotary rotor in the machine, such as Alpine / Hosokawa Micron TSP, Nisshin Engineering Co., Ltd., Turboxifier, Condax / Mitsui Mining Co., CFS-HD, Donaldson Co., Ltd. Donasex, etc. Using a classifier DS / DSX manufactured by NPK, an elbow jet classifier manufactured by Nippon Mining Co., Ltd., a micron separator manufactured by Hosokawa Micron, etc., the toner is classified stepwise to a predetermined toner particle size. The coarse powder generated in the classification step may be reused after returning to the pulverization step or the first-stage classification step. Further, the toner fine powder may be reused by returning to the raw material mixing step and the kneading step. (5) In the case of further external addition treatment, a predetermined amount of the classified product and various known external additives are blended, and the mixture is stirred and mixed with a Henschel mixer, a super mixer or other high-speed stirrer that applies a shearing force to the powder. .

(6) Vibrating sieves such as a gyro shifter, a Sato type vibrating sieve, and an ultrasonic sieve for removing foreign matter and coarse particles;
After sieving using a rotary screen such as a turbo screener, a final toner can be obtained. Further, as a completely different method from the above production method, for example, a suspension polymerization method,
The toner particles may be formed by an emulsion polymerization method, a so-called polymerization toner method. The obtained toner has a softening temperature of 80 to 160 ° C. and a glass transition temperature of 50 to 7
A range of 5 ° C. is preferred. If the softening temperature is lower than 80 ° C., the hot offset property deteriorates and the mechanical strength becomes weak, which is not preferable. On the other hand, if it exceeds 160 ° C., the fixing property deteriorates, which is not preferable. When the glass transition temperature is lower than 50 ° C., toner aggregation and fixation are liable to occur. On the other hand, when the glass transition temperature is higher than 75 ° C., fixing strength is lowered, which is not preferable.

The softening temperature of the toner was measured using a flow tester (C
FT-500, manufactured by Shimadzu Corporation), and about 1 g of a sample was heated at a rate of 6 ° C./min. 1cm ² while heating with
A load of 20 kg / cm ² by the plunger of
It is extruded from a die having a hole diameter of 1 mm and a height of 1 mm, and a temperature corresponding to an intermediate point between the temperature at which the plunger starts to descend and the temperature at which it descends is defined as the softening temperature. Further, the glass transition temperature (hereinafter, referred to as Tg) of the toner is 100 ° C. at a rate of 10 ° C./min using a differential scanning calorimeter (DSC).
After the temperature is once increased as described above, the temperature is cooled to room temperature by air cooling with a fan, and the temperature is again set to a temperature corresponding to an intersection where a tangent is drawn to an inflection point (shoulder) when the temperature is increased.

In the present invention, the softening temperature of a plurality of color toners, for example, the softening temperature (Tc) of a cyan toner, the softening temperature (Tm) of a magenta toner, and the softening temperature (Ty) of a yellow toner are all softening temperatures of a black toner. Lower than the temperature (Tb) and the number average molecular weight of the polyethylene wax in the plurality of color toners, for example, the number average molecular weight (Mnc) of the polyethylene wax in the cyan toner, the number average molecular weight (Mn) of the polyethylene wax in the magenta toner
m) and the number average molecular weight (Mny) of the polyethylene wax in the yellow toner must be lower than the number average molecular weight (Mnb) of the polyethylene wax in the black toner.

At the toner softening temperature, when the black Tb is equal to or lower than any of cyan Tc, magenta Tm and yellow Ty, the gloss of the black image is increased and the matte tone cannot be obtained. It is not preferable. In order for a color image to have high gloss and excellent light transparency, and to obtain a matte tone for a black image, black Tb should have a higher temperature than cyan Tc, magenta Tm, and yellow Ty, and preferably in any case. It is preferable that the temperature is higher than 3 ° C. In order to obtain the softening temperatures of the three primary color toners and the black toner having such a relationship, the material and manufacturing aspects may be selected under appropriate conditions such as different softening temperatures of the three primary colors and the black binder resin.

It is not clear why the number average molecular weight of the polyethylene wax in the three primary color toners having a low toner softening temperature is low and the number average molecular weight of the ethylene wax in the black toner having a high toner softening temperature is preferably high. Except for the relationship, it is assumed that the compatibility, dispersibility, and the like of the components in the toner are deteriorated, and the balance of the charging characteristics, image characteristics, fixing characteristics, and the like is lost, which is not preferable.

The toner used in the full-color image forming method of the present invention may be used as a two-component developer obtained by mixing a toner and a magnetic carrier, or may be used as a one-component toner using no magnetic carrier. In particular, it is preferably used for a one-component toner, and more preferably used for a non-magnetic one-component toner. The full-color image forming method of the present invention is an electrophotographic method in which an image is formed by a thermal fixing method in which a toner is developed by a contact or non-contact non-magnetic one-component developing method, and then the toner is brought into contact with a fixing roll having a built-in heat heater to fix the toner. When used in a recording apparatus, it has a sufficient fixing strength, has no offset phenomenon on the low and high temperature sides, and exhibits useful fixing effects such as no phenomenon that the recording paper is wound around the heat roll.

In particular, the tandem type full-color image forming method is characterized in that the printing speed can be increased as compared with the intermediate transfer method, the multiple transfer method and the like. Therefore, as the toner used in the tandem system, a toner having a quick charge rising property, an appropriate charge amount can be secured, the toner fog on the photoconductor is small, the uniformity of a solid image is good, and the toner consumption is not deteriorated. It was desired, but not always enough. Therefore, the above problem can be solved by using the toner of the present invention in a tandem system.

Hereinafter, an electrophotographic recording apparatus using a non-magnetic one-component toner, which is an example of the full-color image forming method of the present invention, will be described. However, the present invention is not limited to this example. FIG. 1 is a schematic diagram of a main configuration of an electrophotographic recording apparatus, and includes a photoconductor 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6, and a fixing device 7.
have. The photoreceptor 1 is formed of a conductor such as aluminum, for example, and has a photosensitive layer formed by applying a photosensitive conductive material on the outer peripheral surface. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5 along the outer peripheral surface of the photoconductor 1.
Further, a cleaning device 6 is arranged.

The charging device 2 includes, for example, a well-known scorotron charger, roller charger, and the like, and uniformly charges the surface of the photoconductor 1 to a predetermined potential. The exposure device 3 includes the photoconductor 1
The photosensitive surface of the photosensitive member 1 is exposed by an LED, a laser beam, or the like to form an electrostatic latent image on the photosensitive surface. The developing device 4 includes an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45.
Is stored. If necessary, the developing device may be provided with a replenishing device 41 for replenishing toner, and the replenishing device can replenish toner from containers such as bottles and cartridges.

The supply roller 43 is made of a conductive sponge or the like, and is in contact with the developing roller 44. The developing roller 44 is disposed between the photoconductor 1 and the supply roller 43. The developing roller 44 is in contact with the photoconductor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism. The supply roller 43 carries the stored toner and supplies it to the developing roller 44. Developing roller 44
Carries the toner supplied by the supply roller 43 and contacts the surface of the photoconductor 1. Developing roller 44
Is made of a metal roll of iron, stainless steel, aluminum, nickel, or the like, or a resin roll in which a metal roll is coated with a silicon resin, a urethane resin, a fluororesin, or the like. The surface of the developing roll may be smoothed or roughened as necessary.

The regulating member 45 is formed by a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or the like, a metal blade coated with a resin, or the like. The regulating member 45 contacts the developing roller 44,
A predetermined force is applied to the developing roller 44 side by a spring or the like (a general blade linear pressure is 5 to 500 g / cm), and a function of imparting charge to the toner by frictional charging with the toner as necessary is provided. You may. Agitator 4
2 are respectively rotated by a rotation drive mechanism,
The toner is supplied to the supply roller 43 while stirring the toner.
To the side. A plurality of agitators may be provided with different blade shapes, sizes, and the like. The transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are arranged to face the photoconductor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charged potential of the toner, and transfers the toner image formed on the photoconductor 1 to the recording paper P.

The cleaning device 6 comprises a cleaning member such as a urethane blade or a fur brush.
The cleaning device removes the residual toner attached to the photoreceptor 1 and collects the residual toner. The fixing device 7 includes an upper fixing member 71 and a lower fixing member 72, and a heating device 73 is provided inside the upper or lower fixing member.
have. As the fixing member, a known heat fixing member such as a fixing roll in which a metal tube made of stainless steel, aluminum or the like is coated with silicone rubber, a fixing roll in which Teflon resin is coated, a fixing sheet, or the like can be used. Further, a releasing agent such as silicone oil may be supplied to the fixing member to improve the releasing property. Further, a mechanism for forcibly applying pressure to the upper fixing member and the lower fixing member by a spring or the like may be employed. When the toner transferred onto the paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state, cooled after passing through, and cooled on the recording paper P. Is fixed to the toner.

In the electrophotographic developing device configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoconductor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. continue,
The charged photosensitive surface of the photoreceptor 1 is exposed by the exposure device 3 in accordance with an image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, the developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photosensitive member 1. In the developing device 4, the toner supplied by the supply roller 43 is thinned by the developing blade 45, and is triboelectrically charged to a predetermined polarity (here, the same polarity as the charging potential of the photoreceptor 1, and negative polarity). Then, it is carried on the developing roller 44, transported, and brought into contact with the surface of the photoconductor 1.

From the developing roller 44, a toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive member 1 by a so-called reversal developing method. Then, the toner image is transferred to the sheet P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoconductor 1 without being transferred is removed by the cleaning device 6. The final image is obtained by passing the toner on the recording paper P through the fixing device 7 and thermally fixing the toner.

Next, an example of a tandem type electrophotographic recording apparatus using a non-magnetic one-component toner as a full color will be described. FIG. 2 is a schematic diagram of a main structure of a full-color tandem system, which includes a photosensitive member 1, a charging device 2, an exposure device 3, a black developing device 4k, a cyan developing device 4c, a yellow developing device 4y, a magenta developing device 4m, and a transfer device 5. , And a fixing device 7, and a cleaning device is omitted here. A color image can be obtained by superimposing magenta, yellow, cyan, and black toners in multiple layers and adjusting the color to a desired color. In the case of the tandem method, it is better that the color developing unit is located before the black developing unit, and that color mixing due to reverse transfer of black toner is reduced, and that the black developing unit is located behind the color developing unit is only black. When the image is formed in a single color, the color mixture due to the fog of the photoreceptor of the color toner is reduced, and the speed of the black image formation can be increased by conveying the recording paper by short-passing the color developing section. In the case of using the fixing process of the system, it is preferable that the black developing portion having a high toner softening temperature is located at the rearmost portion because the influence of heat of the fixing portion on toner fusion and fixation is small. The toner of the present invention
This is suitable for the tandem type in which the cyan, magenta, and yellow color developing sections are located at the front position, and the black developing section is located after the color developing section. Note that cyan,
The order in which the magenta and yellow color developing units are located can be freely changed at any time.

[0069]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In addition, in each of Examples and Comparative Examples, “parts” simply means “parts by weight”.

[0070]

Example 1 <Preparation of Black Toner K1> Nonlinear polyester resin A1 100 parts Sp: 150 ° C., Tg: 65 ° C. THF insolubles: 20% Acid value: 8 KOHmg / g, Hydroxyl value: 30 KOHmg / g Mn: 2400, Mw: 87,000 ・ 1 part of polyethylene wax a [Mn: 6000, melting point: 133 ° C., density 0.96 kg / m ³ ] ・ Carbon black 5 parts MA-100S manufactured by Mitsubishi Chemical Corporation ・ Charge control agent Orient Chemical Industries Bontron S-34 1 part

The above composition is premixed with a high-speed stirrer, kneaded with a twin-screw continuous extruder, and rapidly cooled while rolling with two rolls. The cooled material was coarsely powdered by a feather mill until it passed the 2 mm line, and then adjusted to a volume average particle size of about 8.7 μm by a jet pulverizer / airflow classifier to obtain a classified toner. The particle size was measured with a Coulter Multisizer. Sp of this toner is 140 ° C., Tg
Was 65 ° C. Next, 100 parts of the classified toner and 1.8 parts of RY50 silica manufactured by Nippon Aerosil Co., Ltd. were mixed with a Henschel mixer, and 0.2 part of R812 silica manufactured by Nippon Aerosil Co., Ltd. was further added and mixed to prepare black toner K1.

[0072]

<Preparation of Cyan Toner C1> 100 parts of linear polyester resin B1 Sp: 110 ° C., Tg: 65 ° C. THF insoluble matter: 0% Acid value: 7 KOH mg / g, Hydroxyl value: 30 KOH mg / g Mn: 4400, Mw: 45,000 ・ 1 part of polyethylene wax b [Mn: 3000, melting point: 129 ° C., density: 0.95 kg / m ³ ] ・ Polypropylene wax p: 2 parts [Mn: 3000, melting point: 132 ° C., density: 0.1. 89 kg / m ³ ] 7 parts of cyan master batch pigment Cyan pigment C.I. I. Pigment Blue 15: 3 40 parts and polyester resin B1 60 parts subjected to masterbatch treatment ・ Charge control agent LR-147 manufactured by Nippon Carlit Co. 1 part

Cyan toner C1 was prepared in the same manner as for black K1, except that the black K1 was formulated as described above. The toner had an Sp of 108 ° C. and a Tg of 65 ° C.

[0074]

[Table 3] <Preparation of magenta toner M1> 9 parts of magenta master batch pigment I. Pigment Red 57:
1 which has been subjected to a masterbatch treatment with 40 parts and polyester resin B1 with 60 parts.

A magenta toner M1 was prepared in the same manner as in cyan C1, except that the cyan C1 master batch pigment was changed from cyan to the above-mentioned magenta. S of this toner
p was 107 ° C and Tg was 65 ° C.

[0076]

<Preparation of Yellow Toner Y1> 9 parts of yellow master batch pigment Magenta pigment C. I. Pigment Yellow 17
40 parts and 60 parts of polyester resin B1 were subjected to master batch processing

The yellow toner Y1 was prepared in the same manner as the cyan C1 except that the cyan C1 master batch pigment was changed from cyan to the yellow color. S of this toner
p was 107 ° C and Tg was 65 ° C.

Using these K1, C1, M1, and Y1 toners, a full-color printer A (A
4 Color speed of plain paper 8 sheets / min; Non-magnetic one-component contact developing method for both primary color and black toner; Developing section order is yellow, magenta, cyan, black; photoreceptor is organic photoconductor; Fixing temperature of plain paper is 170 with fixing method
Table 1 shows the results of evaluation of the image characteristics at (° C.), but all were excellent and good.

[0079]

[Example 5] <Production of toner of cyan C2, magenta M2, and yellow Y2> • 1 part of polyethylene wax c [Mn: 1500, melting point: 103 ° C, density: 0.93]

The cyan C2, magenta M2, and yellow Y are operated in the same manner as the corresponding colors of the toners C1, M1, and Y1 except that the polyethylene b of cyan C1, magenta M1, and yellow Y1 in Example 1 is changed to the polyethylene c.
2 was produced. The Sp / Tg of these toners is such that C2 is 1
08 ° C / 65 ° C, M2 107 ° C / 65 ° C, Y2 10
7 ° C / 65 ° C. These three primary color toners C2 and M
2, Table 1 shows the results of evaluation of image characteristics using a full-color printer A using Y2 and the black toner K1, and all the results were excellent and good.

Example 3 <Preparation of Black Toner K2> Black toner K2 was prepared in the same manner as in toner K1 except that the number of polyethylene a added to black toner K1 in Example 1 was changed to 0.5 part.
Was prepared. The toner has an Sp of 140 ° C. and a Tg of 65.
° C.

<Cyan C3, Magenta M3, Yellow Y
Preparation of 3> Cyan C3, magenta by the same operation as the corresponding color of each of toners C1, M1, and Y1 except that the number of added parts of polyethylene b of cyan C1, magenta M1, and yellow Y1 was changed to 0.5 part. M3 and yellow Y3 were produced. The Sp / Tg of these toners is such that C2 is 108 ° C.
/ 65 ° C, M2 is 107 ° C / 65 ° C, Y2 is 107 ° C /
65 ° C.

The black toner K2 and the three primary color toners C
Table 1 shows the results of evaluating the image characteristics of the full-color printer A using Nos. 3, M3, and Y3. The results are all excellent and good.

[0084]

Comparative Example 1 <Preparation of Black Toner K3> 1 part of polyethylene wax b [Mn: 3000, melting point: 129 ° C., density: 0.95 kg / m ³ ]

The black toner K1 of the black toner K1 of Example 1 was replaced with the above-described polyethylene wax b, except that the polyethylene wax a was changed to the above-described polyethylene wax b.
3 was produced. The toner has an Sp of 140 ° C. and a Tg of 6
5 ° C. This black toner K3 and 3 of Example 1
Table 1 shows the results of evaluating the image characteristics of the full-color printer A using the primary color toners C1, M1, and Y1. The fog on the photoreceptor was high and the fog on the white background was slightly poor.

Comparative Example 2 <Preparation of Black Toner K4> A black toner K4 was prepared in the same manner as in Example 1 except that the polyethylene wax a of the black toner K1 was omitted. The Sp of this toner is 141
° C and Tg were 65 ° C.

Table 1 shows the results of evaluation of image characteristics with the full-color printer A using the black toner K4 and the three primary color toners C1, M1, and Y1 of Example 1. The fog on the photoreceptor is high and the fog on the white background is high. Was also bad.

Comparative Example 3 <Preparation of Black Toner K5> 100 parts of linear polyester resin B1 The procedure of Example 1 was repeated except that the nonlinear polyester resin A1 of the black toner K1 of Example 1 was changed to the linear polyester resin B1. A black toner K5 was produced in the same operation as K1. Sp of this toner is 108 ° C. and Tg is 65 ° C.
Met.

Table 1 shows the results of evaluating the image characteristics of the full-color printer A using the black toner K5 and the three primary color toners C1, M1, and Y1 of Example 1. The fog on the photosensitive member is high, and the fog on the white background is high. The image was inferior, was a glossy black image with high glaring, and had a high image density, which was not preferable.

[Evaluation Method] The test method for each evaluation item was as follows. 1. Image density The image area printed using plain paper with a given full-color printer is a spectral colorimeter X-Rit manufactured by Nippon Lithographic Equipment Co., Ltd.
The reflection density was measured using e938 (light source: D65 light source, viewing angle 2 °, response: T), and the result was used as the image density. 2. White background fog Printing is performed using plain paper with a predetermined full-color printer, and the white background, which is a non-image part, is a spectral colorimeter X-Rite938 manufactured by Nippon Lithographic Equipment Co., Ltd. (light source: D65 light source, viewing angle 2 °, response: T )), L ^* a ^* b ^* is measured, and the color difference (△) is calculated from the white background L ^* a ^* b ^* before and after printing by the following equation.
E ₁ ) was determined, and a fog on a white background was determined.

[0091]

## EQU3 ## Color difference (△ E ₁ ) = [(L ^* _i− L ^* _p ) ² + (a
^* _i- a ^* _p ) ² + (b ^* _i- b ^* _p ) ² ] ^1/2 L ^* _i , a ^* _i , b ^* _i : white background value L ^* _p , a ^* _p , b before printing ^* _p : White background value after printing

3. Fog on photoreceptor Print on plain paper with toner from a specified full-color printer, print in blank paper mode, forcibly stop during printing, and apply fog on the photoreceptor (from the transfer section after the development section on the photoconductor). The toner (front toner) is collected with a 3M company mending tape, and after collection, is attached to plain paper (white paper). Measure the L ^* a ^* b ^* of the fogged portion of the attached tape using a spectrophotometric densitometer X-Rite 938 (light source: D65 light source, viewing angle 2 °, response: T) manufactured by Nippon Lithographic Equipment Co., Ltd., and before and after fogging. The color difference (ΔE ₂ ) was determined from L ^* a ^* b ^* of the following formula according to the following equation, and the result was defined as a white background fog.

[0093]

## EQU4 ## Color difference (△ E ₂ ) = [(L ^* _j− L ^* _q ) ² + (a
^{_{* J -a * q) 2 +}} (b * j -b * q) 2] 1/2 L * j, a * j, b * j: tape value of the previous head collecting ^{_{L * q, a * q,}} b ^* _q : Tape value after fogging

4. Gloss The solid image was printed on plain paper with a predetermined full-color printer, and the gloss value measured with a gloss meter VG-2000 (angle 75 °) manufactured by Nippon Denshoku Industries Co., Ltd. was defined as the gloss.

[0095]

[Table 7]

[0096]

According to the present invention, in a full-color image forming method used in an electrophotographic recording apparatus or the like, an image having excellent gloss balance of a color image and a black image, good toner charging characteristics, image density, fog, etc. It has good characteristics, stable and good durability characteristics even when continuous printing is performed, and also has good fixability in thermal fixing, and exhibits excellent effects.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main configuration of an electrophotographic recording apparatus using a non-magnetic one-component toner which is an example of a full-color image forming method of the present invention.

FIG. 2 is a schematic diagram showing a main configuration of an electrophotographic recording apparatus used in a full-color tandem system which is an example of a full-color image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 charging device 3 exposure device 4 developing device 5 transfer device 6 cleaning device 7 fixing device 4k black developing device 4y yellow developing device 4c cyan developing device 4m magenta developing device 41 replenishing device 42 agitator 43 supply roller 44 developing roller 45 regulation Member 71 Upper fixing member 72 Lower fixing member 73 Heating device T Toner P Recording paper

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 15/20 101 G03G 9/08 346 365 (72) Inventor Takeshi Owada 1 Fukudacho, Joetsu-shi, Niigata Mitsubishi Chemical Corporation Naoetsu Office (72) Inventor Teruki Senoguchi 1 Fukudacho, Joetsu City, Niigata Prefecture Mitsubishi Chemical Corporation Naoetsu Office (72) Inventor Masakazu Sugihara 1 Fukudacho, Joetsu City, Niigata Mitsubishi Chemical Corporation Naoetsu Office F term (reference) 2H005 AA01 AA06 AA21 CA04 CA08 CA13 CA14 CA21 CA22 CA25 CB03 CB18 DA02 EA03 EA06 EA07 FB01 2H030 AA06 AB02 AD01 BB23 BB53 BB63 2H033 BA58 BB01 BB28

Claims (26)

[Claims] 1. A full-color image forming method for forming a color image using a plurality of color toners and a black toner, wherein the plurality of color toners and the black toner include at least a binder resin, polyethylene wax, a colorant, and charge control. The softening temperature of each of the plurality of color toners is lower than the softening temperature of the black toner, and the number average molecular weight of the polyethylene wax in each of the plurality of color toners is the number of polyethylene waxes in the black toner. A full-color image forming method characterized by having a molecular weight smaller than the average molecular weight. 2. A full-color image forming method for forming a multicolor image using at least three primary color toners of cyan, magenta and yellow and a black toner, wherein the three primary color toners and the black toner are at least a binder resin and a polyethylene wax, respectively. , A colorant, and a charge control agent, and the softening temperature (Tc) of the cyan toner, the softening temperature (Tm) of the magenta toner, and the softening temperature (Ty) of the yellow toner are all lower than the softening temperature (Tb) of the black toner. The number average molecular weight (Mnc) of the polyethylene wax in the cyan toner, the number average molecular weight (Mnm) of the polyethylene wax in the magenta toner, and the number average molecular weight (Mny) of the polyethylene wax in the yellow toner are all low. The polyethylene wax in the toner must have a number average molecular weight (Mnb) And a full-color image forming method. 3. The polyethylene wax has a number average molecular weight (Mnc, Mnm, Mny, and Mnb) of 1
3. The full-color image forming method according to claim 2, wherein the range is from 000 to 8000. 4. The melting point (MP) of the polyethylene wax.
c, MPm, MPy, and MPb) are all 80 to 15
4. The full-color image forming method according to claim 2, wherein the temperature is in a range of 0.degree. 5. The amount of addition in the polyethylene wax in the three primary color toners and the black toner is 10%.
5. The full-color image forming method according to claim 2, wherein the amount is 0.1 to 6 parts by weight with respect to 0 parts by weight. 6. The full-color image forming method according to claim 2, wherein the binder resin is a styrene-based resin or a polyester resin. 7. The full-color image forming method according to claim 6, wherein the binder resin is a linear or non-linear polyester resin. 8. The full color printer according to claim 6, wherein the binder resin for the three primary color toners is a linear or non-linear polyester resin, and the binder resin for the black toner is a non-linear polyester resin. Image forming method. 9. The softening temperature (Tc, Tm, Ty) of the three primary color toners and the softening temperature (Tb) of the black toner.
9. The full-color image forming method according to claim 2, wherein each of the temperature ranges from 80 to 160 [deg.] C. 10. The softening temperature of the three primary color toners (Tc,
10. The full-color image forming method according to claim 2, wherein each of Tm and Ty) is lower than the softening temperature (Tb) of the black toner by 3 ° C. or more. 11. The colorant of the cyan toner contains at least cyan: C.I. I. 11. The full-color image forming method according to claim 2, further comprising a blue pigment of CI Pigment Blue 15: 3 or 15: 4. 12. The colorant of the magenta toner contains at least magenta: C.I. I. Pigment Red 57:
The full-color image forming method according to any one of claims 2 to 10, wherein the method comprises any one of red, red and red pigments of 1, 122, 146, 184, 238, and Pigment Violet 19. 13. The colorant of the yellow toner, wherein at least yellow: C.I. I. Pigment Yellow 13,
17, 17, 74, 150, 155, 18
The full-color image forming method according to any one of claims 2 to 10, further comprising a yellow pigment of any one of (1) and (185). 14. The full-color image forming method according to claim 2, wherein the colorant of the black toner contains at least carbon black or magnetite. 15. The full-color image forming method according to claim 2, wherein the charge control agent is a negatively chargeable charge control agent. 16. The charge control agent for the three primary color toners of cyan, magenta and yellow contains at least the following general formula [
2. The charge control agent according to claim 1, wherein the charge control agent for the black toner is an azo metal compound.
6. The full-color image forming method according to 5. Embedded image (In the formula, R _{1 to} R ₄ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and X ⁺ represents a cation.) 17. The charge control agent for the three primary color toners, wherein in formula [I], R ^{1 to} R ⁴ are phenyl groups;
17. The full-color image forming method according to claim 2, wherein ⁺ is a potassium ion, and the metal component in the azo metal compound of the black toner is chromium or iron. 18. The full-color image forming method according to claim 16, wherein the azo-based metal compound charge controlling agent of the black toner is a compound represented by the following general formula [II]. Embedded image (Where A to D may be the same or different,
Represents an optionally substituted benzene ring. X ⁺ represents a cation. ) 19. The full-color image forming method according to claim 16, wherein the azo metal compound charge control agent of the black toner is a compound represented by the following general formula [III]. Embedded image (In the formula, E to J may be the same or different, and represent a benzene ring which may be substituted. X ⁺ represents a cation.) 20. The method according to claim 2, wherein the three primary color toners and the black toner are fixed by a heating contact method.
20. The full-color image forming method according to any one of Items 1 to 19. 21. When the three primary color toners and the black toner are 1
21. The full-color image forming method according to claim 2, wherein the image is developed by a component developing system. 22. The full-color image forming method according to claim 21, wherein the one-component developing method for the three primary color toners is a non-magnetic one-component developing method comprising at least a developing roll and a toner layer regulating member. . 23. The method according to claim 2, wherein the full-color image forming method is used in a tandem system.
3. The method for forming a full-color image according to item 1. 24. In the tandem system, cyan,
24. The full-color image forming method according to claim 23, wherein the developing unit for the three primary color toners of magenta and yellow is located in front, and the developing unit for the black toner is located after the developing unit for the three primary color toners. 25. The full-color image forming method according to claim 2, wherein the colorant of the black toner is acidic carbon black. 26. The full-color image forming method according to claim 2, wherein the three primary color toners and the black toner are fixed by a heating method.