JP2002072567A - Full-color image forming method and full-color image and electrostatic charge image developing toner, and two-component type developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the toners having superior preservation property and blocking resistance, without impairing density, color developability, transparency, etc., of fixed images by allowing the fixing at a temperature to be lower than heretofore and an image forming method and an image form method and to provide a two-component type developer which will not induce problems, such as filming to a photoreceptor, etc. SOLUTION: This full-color image forming method has a developing process step of developing the electrostatic latent image, formed on at least the surface of a latent image carrying member by using a layer of the developer formed on the surface of a developer-carrying member to obtain a toner image on the surface of the latent image carrying member, a transfer process step of obtaining the transferred image, by transferring this toner image to the surface of a material to be transferred and a fixing process step of obtaining the fixed image by fixing the transferred image. The developer described contains toners, composed of toner particles consisting of at least coloring agents and a binder resin consisting mainly of a crystalline resin. The melting point of the toners is 50 to 120 deg.C and the average size of the crystals of the crystalline resin in the fixed image is <=3 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image and a two-component developer used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like, and a method for forming a full-color image and the method. It relates to the resulting full-color image.

[0002]

2. Description of the Related Art Conventionally, as a fixing method of a toner for developing an electrostatic image, a pressure fixing method using only a pressure roll at normal temperature, a contact heating type fixing method using a heating roll, etc .; an oven fixing method using oven heating, a xenon lamp. A non-contact fixing method such as an electromagnetic fixing method using a microwave or a solvent fixing method using a solvent vapor. Among these, an oven fixing method using heat and a contact heating fixing method are mainly used from the viewpoint of reliability and safety. In particular, the contact heating type fixing method using a heating roll or a heating belt usually includes a heating roll or a heating belt provided with a heating source and a pressure roll or a pressure belt, and is transferred to the surface of the heating roll or the heating belt. The fixing is performed by passing the toner image surface of the material while making pressure contact with the material. Therefore, since the surface of the heating roll or the heating belt and the toner image surface of the transfer material are in direct contact with each other, it has high thermal efficiency and can be fixed quickly, and is widely used.

In these thermal fixing systems, the time from when the power is turned on until the temperature of the fixing machine rapidly rises to the operating temperature and becomes a state in which fixing is possible, that is, the so-called warm-up time is shortened, and the energy consumption is reduced. It is desired that the toner can be fixed at a lower temperature. Particularly in recent years, from the viewpoint of energy saving, it is desired to stop the power supply to the fixing device when not in use, and the temperature of the fixing device needs to reach the feasible temperature instantaneously with the power supply. Fixation is needed.

Further, in the contact heating type fixing system, by lowering the fixing temperature, the service life of a fixing member such as a heating roll can be extended, which is preferable from the viewpoint of cost. However, in the conventional method, lowering the fixing temperature of the toner also lowers the glass transition point of the toner particles at the same time, making it difficult to achieve compatibility with the storability of the toner.
In order to achieve both low-temperature fixing and toner storability, it is necessary that the toner has a so-called sharp melt property in which the viscosity of the toner rapidly decreases in a high temperature region while maintaining the glass transition point of the toner at a higher temperature.

The resin used for the toner usually has a certain degree of variation in glass transition point, molecular weight, and the like. Therefore, in order to obtain a sharp melt property, it is necessary to make the resin composition and molecular weight extremely uniform. In order to obtain a suitable resin, it is necessary to adjust the molecular weight of the resin by using a special production method or treating the resin by chromatography or the like. Therefore, the cost of resin production increases, and unnecessary resin is generated at that time, which is not preferable from the viewpoint of environmental protection in recent years.

In order to realize such low-temperature fixability, a method using a crystalline resin as a binder resin (JP-A-57-36586, JP-A-2-79049, etc.) has been studied. . By using the crystalline resin, the hardness of the toner is maintained below the melting point of the crystal, and when the temperature exceeds the melting point, the viscosity is sharply reduced together with the melting of the crystal, whereby low-temperature fixing is achieved. For the same effect, a method of combining a crystalline resin and a non-crystalline resin (JP-A-2-79860, JP-A-4-184)
358) and a method of combining two or more crystalline resins (Japanese Patent Laid-Open No. 62-129867). However, when these crystalline resins are used as binder resins, their light transmittance is greatly inferior to non-crystalline resins due to their crystalline structure. This is because light transmittance is impaired due to fluctuations in the average refractive index and optical anisotropy of the crystal of the crystalline resin, fluctuations in the size and orientation of the crystal, and the like. Further, even when a crystalline resin and a non-crystalline resin are combined, the same problem occurs not only when they are compatible or non-compatible. Therefore, even in a single color toner, O
In addition to the HP transmittance, the density is reduced and the reproducible color gamut is narrowed. Especially in full color copiers, cyan,
Since it is common to form a full-color image by superimposing each of the magenta and yellow toners, if the light transmittance of each color image is insufficient, the color reproducibility due to the superimposition of these images may be insufficient. turn into.

When the crystallinity of the crystalline resin used is low, the proportion of the amorphous portion contained in the crystalline resin increases. In addition, there is a problem in that the fluidity is reduced, filming on a photoreceptor (latent image carrier), and filming on a carrier is deteriorated in the case of the two-component developing method.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to solve the problems. In other words, an object of the present invention is to provide a full-color image forming method capable of fixing at a lower temperature than before, thereby greatly reducing energy in a fixing step and shortening a warm-up time. And Another object of the present invention is to provide a toner and an image forming method which are excellent in storability and blocking resistance without impairing the density, color developability, transparency and the like of a fixed image after fixing. Another object of the present invention is to provide a two-component developer which does not cause a problem such as filming on a photoreceptor or a carrier.

[0009]

The above object is attained by the following means. That is, in the full-color image forming method of the present invention, at least the electrostatic latent image formed on the surface of the latent image carrier is developed using the layer of the developer formed on the surface of the developer carrier, and the latent image is developed. A developing step of obtaining a toner image on the surface of the image carrier, a transferring step of transferring the toner image to the surface of the transfer material to obtain a transferred image, and a fixing step of fixing the transferred image to obtain a fixed image. In a full-color image forming method, the developer contains at least a toner composed of toner particles composed of a colorant and a binder resin containing a crystalline resin as a main component, and the toner has a melting point. 5
0 to 120 ° C., and the crystal size of the crystalline resin in the fixed image is 3 μm or less on average.

The crystalline resin preferably contains a nucleating agent, and the nucleating agent preferably contains one or more organic nucleating agents. The colorant is preferably a pigment, and the crystalline resin is preferably a polyester resin.

The full-color image of the present invention is obtained by the above-described full-color image forming method.

Further, the toner for electrostatic charge development of the present invention comprises:
A toner used in the full-color image forming method, wherein the crystalline resin contains a nucleating agent. The crystalline resin is preferably a polyester resin.

[0013] The two-component developer of the present invention is a two-component developer comprising a carrier and a toner, wherein the toner is the toner for electrostatic charge development.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with respect to each item. ≪A. Toner The toner for electrostatic charge development of the present invention is a toner used in a full-color image forming method described later, and a crystalline resin which is a main component of a binder resin contains a nucleating agent.

{1. Toner particles—Toner particles in the present invention are composed of at least a colorant and a binder resin containing a crystalline resin containing a nucleating agent as a main component, and further contain other components as necessary.

<1. Binder Resin> (1. Crystalline Resin) The binder resin used in the present invention contains a crystalline resin as a main component. The content of the crystalline resin is 50 to
It is preferably 100 parts by weight, more preferably 70 to 100 parts by weight. Note that a crystalline resin refers to a resin in which an endothermic peak due to a melting point is observed in differential scanning calorimetry (DSC).

The polymerizable monomer constituting the crystalline resin in the present invention is not particularly limited as long as it can constitute a crystalline resin. Specific examples of the polymerizable monomer and the resin composed of the polymerizable monomer include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecandioic acid, and long-chain alkyl such as tridecandioic acid. (Meth) acrylic acid; polyester resins using dicarboxylic acids of the above or long-chain alkyl or alkenyl diols such as butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and batyl alcohol; Amyl, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, tridecyl (meth) acrylate , Myristyl (meth) acrylate, (meth) acrylic Vinyl resins using long-chain alkyl or alkenyl (meth) acrylates such as cetyl, stearyl (meth) acrylate, oleyl (meth) acrylate, and behenyl (meth) acrylate; Polyester resins are preferred from the viewpoints of adhesion to paper and charging properties.

If necessary, a monohydric acid such as acetic acid or benzoic acid, or a monohydric alcohol such as cyclohexanol or benzyl alcohol may be used for the purpose of adjusting an acid value or a hydroxyl value. it can.

In the present invention, compounds having a shorter chain alkyl group, alkenyl group, aromatic ring and the like can be used in addition to the above-mentioned polymerizable monomers for the purpose of adjusting the melting point, molecular weight and the like. As a specific example, when dicarboxylic acids are used as the polyester resin, succinic acid, malonic acid, alkyldicarboxylic acids such as oxalic acid; phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 4,
4′-bibenzoic acid, 2,6-naphthalenedicarboxylic acid,
Aromatic dicarboxylic acids such as 1,4-naphthalenedicarboxylic acid; dipicolinic acid, dinicotinic acid, quinolinic acid;
Examples thereof include nitrogen-containing aromatic dicarboxylic acids such as 3-pyrazinedicarboxylic acid, and when diols are used as the polyester resin, diols of short-chain alkyl such as succinic acid, malonic acid, acetone dicarboxylic acid, and diglycolic acid. And when a short-chain alkyl vinyl polymerizable monomer is used, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
(Meth) acrylates of short-chain alkyl or alkenyl such as butyl (meth) acrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone and vinyl Ethyl ketone and vinyl isopropenyl ketone; olefins such as ethylene, propylene, butadiene and isoprene; and the like. These compounds may be used alone or in combination of two or more.

Further, a crosslinking agent can be added to the crystalline resin of the present invention, if necessary. Specific examples of the crosslinking agent include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, divinyl naphthalene dicarboxylate, Polyvinyl esters of aromatic polycarboxylic acids such as divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; unsaturated heterocyclic compounds such as pyrrole and thiophene; vinyl pyromutinate; Vinyl esters of carboxylic acids which are unsaturated heterocyclic compounds such as vinyl furancarboxylate, vinyl pyrrole-2-carboxylate and vinyl thiophenecarboxylate; butanediol methacrylate, hexanediol acrylate, octanediol (Meth) acrylates of linear polyhydric alcohols such as methacrylate, decanediol acrylate and dodecanediol methacrylate; branched or substituted polyvalents such as neopentyl glycol dimethacrylate, 2-hydroxy or 1,3-diacryloxypropane (Meth) acrylates of alcohols; polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di (meth) acrylates; divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, vinyl itaconate / Divinyl, divinyl acetone dicarboxylate,
Divinyl glutarate, divinyl 3,3′-thiodipropionate, trans-divinyl aconitate / trivinyl, divinyl adipate, divinyl pimerate, divinyl suberate, divinyl azelate, divinyl sebacate, divinyl dodecane diacid, brasilic acid Polyvinyl esters of polycarboxylic acids such as divinyl; and the like.

When the crystalline resin is a polyester resin, fumaric acid, maleic acid, itaconic acid, trans-
It is also possible to use a method in which unsaturated polycarboxylic acids such as aconitic acid are copolymerized in a polyester and then cross-linked by using a multiple bond portion in the resin or another vinyl compound. In the present invention, these crosslinking agents may be used alone or in combination of two or more.
Further, the polymerizable monomer can be polymerized by condensation polymerization. As the condensation polymerization catalyst, known catalysts can be used, and specific examples include titanium tetrabutoxide, dibutyltin oxide, germanium dioxide, antimony trioxide, tin acetate, zinc acetate, tin disulfide and the like. .

When the crystalline resin is a vinyl resin, the polymerizable monomer can be polymerized by radical polymerization. The radical polymerization initiator is not particularly limited as long as it is capable of emulsion polymerization. Specifically, hydrogen peroxide; acetyl peroxide, cumyl peroxide, tert-peroxide
Peroxides such as butyl, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide; ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate , Tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid
tert-butyl hydroperoxide; performic acid-ter
t-butyl, tert-butyl peracetate, perbenzoic acid
tert-butyl, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, perN- (3-
Peroxides such as tolyl) -tert-butyl carbamate; 2,2′-azobispropane, 2,2′-dichloro-2,2′-azobispropane, 1,1′-azo (methylethyl) Diacetate, 2,2′-azobis (2-
Amidinopropane) hydrochloride, 2,2'-azobis (2-
Amidinopropane) nitrate, 2,2′-azobisisobutane, 2,2′-azobisisobutylamide, 2,2 ′
-Azobisisobutyronitrile, 2,2'-azobis-
Methyl 2-methylpropionate, 2,2'-dichloro-
2,2'-azobisbutane, 2,2'-azobis-2-
Methylbutyronitrile, dimethyl 2,2'-azobisisobutyrate, 1,1'-azobis (sodium 1-methylbutyronitrile-3-sulfonate), 2- (4-methylphenylazo) -2-methylmalonodi Nitrile,

4,4'-azobis-4-cyanovaleric acid,
3,5-dihydroxymethylphenylazo-2-methylmalonodinitrile, 2- (4-bromophenylazo)-
2-allylmalonodinitrile, 2,2'-azobis-2
-Methylvaleronitrile, dimethyl 4,4'-azobis-4-cyanovalerate, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobiscyclohexanenitrile, 2,2'-azobis -2-propylbutyronitrile, 1,1'-azobis-1-chlorophenylethane, 1,1'-azobis-1-cyclohexanecarbonitrile, 1,1'-azobis-1-cycloheptanenitrile, 1,1 '-Azobis-1-phenylethane,
1,1′-azobiscumene, ethyl 4-nitrophenylazobenzylcyanoacetate, phenylazodiphenylmethane, phenylazotriphenylmethane, 4-nitrophenylazotriphenylmethane, 1,1′-azobis-
1,2-diphenylethane, poly (bisphenol A-
Azo compounds such as 4,4'-azobis-4-cyanopentanoate and poly (tetraethylene glycol-2,2'-azobisisobutyrate); 1,4-bis (pentaethylene) -2- Tetrazen, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazen; and the like. The above polymerization initiator can also be used as an initiator of a crosslinking reaction.

The non-crystalline resin optionally used together with the crystalline resin includes styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene and isoprene; vinyl acetate and vinyl propionate. And vinyl esters such as vinyl benzoate;
A such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, etc.
Homopolymers or copolymers of methylene aliphatic monocarboxylic acid esters; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone; A typical example of the binder resin is polystyrene, styrene-alkyl acrylate copolymer,
Styrene-methacrylic acid copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified Rosin, paraffins and the like can be mentioned, and among them, polyester resin is preferable.

The softening point of these non-crystalline resins is 80 to 15
0 ° C is preferable, and 90 to 130 ° C is more preferable. 80
If the temperature is lower than 150 ° C., the heat preservability is reduced. The glass transition point is preferably from 50 to 75C, more preferably from 55 to 70C. If the temperature is lower than 50 ° C., the heat preservability decreases,
If it is higher, the low-temperature fixability of the crystalline resin may be impaired.

(2. Crystal nucleating agent) When a crystal nucleating agent is added / dispersed in a crystalline resin, the crystal nucleating agent functions as a large number of active nuclei, promotes crystal formation, increases the number of crystals, and increases the crystal size. And homogenize the crystal size,
This is preferable because the transparency of the resin can be improved.
Further, the crystal nucleating agent also has the effect of improving the crystallinity of the crystalline resin, and since the ratio of the amorphous portion contained in the crystalline resin is reduced, the storage stability and the blocking resistance, or the fluidity are improved. , Filming on the photoreceptor, and in the case of the two-component developing method, preventing filming on the carrier,
In addition, long-term charging stability over time can be imparted.

As the nucleating agent that can be contained in the crystalline resin of the present invention, any known nucleating agent, either an inorganic nucleating agent or an organic nucleating agent, can be used. Specifically, examples of the inorganic crystal nucleating agent include silica, talc, kaolin, alumina, alum, and titanium oxide.
Dibenzylidene sorbitol; lower alkyl dibenzylidene sorbitol such as methyldibenzylidene sorbitol; metal benzoate such as aluminum hydroxy-di (t-butylbenzoate); bis (4-t-phosphate) represented by the following formula (I): -Butylphenyl) sodium, phosphate metal salts such as sodium 2,2'-methylenebis (4,6-di-t-butylphenyl) phosphate represented by the following formula (II); sodium montanate and the like. Straight-chain fatty acid metal salts; rosin acid partial metal salts; and the like. In particular, an organic crystal nucleating agent such as dibenzylidene sorbitol also acts as a gelling agent, and the crystal can be further refined / homogenized by a percolation network between the crystal nucleating agents.

[0028]

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[0029]

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Further, the organic crystal nucleating agent acts on the polymer chain which moves thermally in the polymer solution to reduce the degree of supercooling of the crystallinity, increase the number of crystals, and refine the crystals. .
Furthermore, the crystal particle diameter of the polyester resin in which the crystal nucleating agent was dispersed was 10 μm or more irrespective of the heat history before the dispersion by a polarizing microscope observation.
It is observed that the crystal is a fine crystal of μm or less.

As a method of dispersing the organic crystal nucleating agent, it is preferable to dissolve or sufficiently disperse the organic crystal nucleating agent in the solvent in which the crystalline resin is dissolved, and then distill off the solvent.

When the organic crystal nucleating agent is intended to be used as a resin for a color toner, the organic crystal nucleating agent is desirably white.
Further, the organic crystal nucleating agent is insolubilized below the melting point of the crystalline resin, and is desired to have good affinity with the crystalline resin.

The content of these nucleating agents is 0.1% with respect to 100 parts by weight of the crystalline resin in the case of the inorganic nucleating agent.
The content is preferably from 20 to 20 parts by weight, more preferably from 0.3 to 10 parts by weight. In the case of an organic crystal nucleating agent, the amount is preferably 0.005 to 10 parts by weight, and
-5 parts by weight is more preferred. In the case of an inorganic crystal nucleating agent, if the content is less than 0.1 part by weight, the function as a crystal nucleating agent is not sufficiently exhibited. Depending on the type of the agent, there is a concern about manufacturability and image gloss due to a remarkable improvement in the elastic modulus due to gelation. Further, in the case of titanium oxide or the like, the transparency and the coloring property are adversely reduced. When the content of the organic crystal nucleating agent is also less than 0.005 parts by weight, and
When the amount is more than 10 parts by weight, the same phenomenon as in the case of the inorganic crystal nucleating agent occurs. An organic crystal nucleating agent is preferable because an effect can be exhibited with a small amount as compared with an inorganic crystal nucleating agent, and a bad effect caused by adding a large amount of a crystal nucleating agent can be suppressed. Further, an inorganic crystal nucleating agent within the above content range,
Regardless of the organic nucleating agent, two or more nucleating agents may be used in combination. When both the inorganic crystal nucleating agent and the organic crystal nucleating agent are contained, the total amount of the crystalline resin 10
It is preferably 0.005 to 20 parts by weight with respect to 0 parts by weight.

(3. Colorant) The colorant for the toner particles in the present invention may be either a dye or a pigment, but is preferably a pigment from the viewpoint of light resistance and water resistance. Preferable pigments include inorganic pigments such as red iron, blue blue, and titanium oxide; azo pigments such as fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, and para brown; phthalocyanine pigments such as copper phthalocyanine and metal-free phthalocyanine; Condensed polycyclic pigments such as tron yellow, dibromoanthrone orange, perylene red, quinacridone red, and dioxazine violet; and the like.

More specifically, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green, lamp black, rose bengal, quinacridone, Benzidine yellow, C.I. I.
Pigment Red 48: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122,
C. I. Pigment Red 185, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 1
7, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 74, C.I. I. Pigment Blue 15: 1, C.I.
I. Pigment Blue 15: 3 and the like. These may be used alone or in combination of two or more. Further, disperse dyes, oil-soluble dyes and the like can also be used. The content of these colorants is preferably from 0.1 to 30 parts by weight, more preferably from 1 to 20 parts by weight, based on 100 parts by weight of the binder resin. By appropriately selecting the type of the colorant, a yellow toner, a magenta toner, a cyan toner, a black toner, and the like can be obtained.

(4. Other Components) The toner particles in the present invention contain the above-mentioned binder resin and colorant as essential components, but further contain other components as necessary. Other components that can be added to the toner particles include a release agent and a charge control agent.

Examples of the release agent include polyolefin waxes such as polyethylene and polypropylene; aliphatic hydrocarbon waxes such as microcrystalline wax and paraffin wax; fatty acid waxes such as carnauba wax and montanic acid ester wax; silicone resins; Known release agents such as rice wax and carnauba wax can be used. The content of the release agent is preferably 1 to 20 parts by weight based on 100 parts by weight of the binder resin,
10 parts by weight is more preferred. The melting point of the release agent is 50
-120 ° C is preferred, and 60-100 ° C is more preferred. When the melting point of the release agent is less than 50 ° C., the change temperature of the release agent is too low, and the blocking resistance is poor, and the developability is deteriorated when the temperature in the copying machine is increased. 120
When the temperature exceeds ℃, the change temperature of the release agent becomes high, and the low-temperature fixability of the crystalline resin is impaired.

As the charge control agent, a chromium azo dye,
Examples include iron-based azo dyes, aluminum-based azo dyes, and salicylic acid metal complexes. The addition amount of the charge control agent is 0.01 to 100 parts by weight of the crystalline resin.
5 parts by weight are preferred.

The surface of the toner particles may be covered with a surface layer. The surface layer desirably does not significantly affect the mechanical properties and melt viscoelastic properties of the entire toner. For example, if the non-melting or high-melting surface layer covers the toner thickly, the low-temperature fixability due to the use of the crystalline resin cannot be sufficiently exhibited. Therefore, the thickness of the surface layer is desirably small, and preferably 0.001 to 0.5 μm.

In order to form a thin surface layer having a thickness of 0.001 to 0.5 μm, a method of chemically treating the surface of the toner particles is preferably used. It is preferable that a polar group is introduced into a component constituting the surface layer, and the bonding strength between the toner and a transfer body such as paper increases by chemically bonding. The polar group may be any polar functional group, for example, a carboxyl group, a carbonyl group, an epoxy group, an ether group, a hydroxyl group, an amino group, an imino group, a cyano group, an amide group, an imide group, Examples include an ester group and a sulfone group.

As a method of chemically treating, for example,
Examples thereof include a method of oxidizing with a strong oxidizing substance such as a peroxide, ozone oxidation, and plasma oxidation, and a method of bonding a polymerizable monomer having a polar group by graft polymerization. By the chemical treatment, the polar group is firmly bonded to the molecular chain of the crystalline resin by a covalent bond.

As described above, by using a crystalline resin in which a crystal nucleating agent is dispersed as the binder resin in the toner particles, it is possible to obtain a toner for electrostatic charge development which can satisfy the fixability at a low temperature. When the shape of the toner particles is made spherical by a method for producing toner particles described later, transfer efficiency can be improved.

The volume average particle diameter of the toner particles in the present invention is preferably from 1 to 12 μm, more preferably from 3 to 9 μm, and the number average particle diameter is also from 1 to 12 μm.
μm is preferable, and 3 to 9 μm is more preferable.

The volume average particle diameter and the number average particle diameter can be determined, for example, by using a Coulter counter [TA-II] type (manufactured by Coulter) with an aperture diameter of 50 μm. The measurement is performed after the toner particles are dispersed in an aqueous electrolyte solution (aqueous isoton solution) and ultrasonically dispersed for 30 seconds or more.

The particle size distribution of the toner particles for electrostatic charge development of the present invention is preferably from 1.0 to 1.6, and more preferably from 1.0 to 1.6.
-1.3 is more preferable. For the measurement of the particle size distribution, for example, using a Coulter counter [TA-II] type (manufactured by Coulter Co., Ltd.), a 16% volume average particle diameter (d ¹⁶⁾ occupying 16% of the total volume integrated from the large particle side of the Coulter counter is used. ) And an 84% volume average particle diameter (d ⁸⁴ ) occupying 84% of the cumulative volume similarly integrated from the large particle side, and the square root of the ratio (d ¹⁶ / d ⁸⁴ ) is obtained. be able to.

<2. Method for Producing Toner Particles> The toner particles of the present invention can be produced by a kneading and pulverizing method, but are produced by a wet production method having at least a step of producing toner particles by a suspension polymerization method or an emulsion aggregation method. Is preferred. Here, the emulsion aggregation method is a method in which emulsion particles of a binder resin are aggregated and coalesced with a coloring agent, a nucleating agent to be added as necessary, and other components. In the case of the emulsion aggregation method, the emulsified particles may be those prepared by an emulsion polymerization method, or those obtained by dissolving a binder resin in a solvent and finely dispersing the same in an aqueous medium.

On the other hand, the suspension polymerization method is to prepare a dispersion suspension in which a binder resin monomer, a crystal nucleating agent, a colorant and other components are dispersed in an aqueous medium, and thereafter, the solvent is removed. It is preferable that the method includes the following steps.

A mixing step of dissolving or dispersing a crystalline resin as a binder resin and a colorant in a solvent to prepare a mixed solution, adding the mixed solution to an aqueous medium and using an emulsifying machine having rotating blades or the like; A dispersion suspension step of preparing a dispersion suspension in which particles are formed by dispersing and suspending the suspension, heating the dispersion suspension, and optionally forming a crosslinked structure on the particles (suspension droplets) by a radical reaction. A crosslinking step to be introduced, and a solvent removing step to remove a solvent from the dispersion suspension. Hereinafter, each of the above steps will be described.

Mixing step: The polymerizable monomer of the crystalline resin, the solvent, and the catalyst are reacted by an ordinary method in an inert atmosphere to prepare a crystalline resin. The crystalline resin is dissolved in a suitable solvent, and a nucleating agent is added and dissolved. After dissolution, the solvent is distilled off and dried to prepare a crystalline resin in which a nucleating agent is dispersed. The crystalline resin in which the nucleating agent is dispersed and the colorant are dispersed in a solvent using a sand mill or the like to prepare a dispersion.

When the crystalline resin is a polyester resin,
Examples of the solvent for dissolving the polymerizable monomer include alcohols such as methanol, ethanol, propanol and butanol; polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol and triethylene glycol; methyl cellosolve, ethyl cellosolve and the like. Cellosolves; ketones such as acetone, methyl ethyl ketone and ethyl acetate; ethers such as tetrahydrofuran; hydrocarbons such as benzene, toluene and hexane; water; These can be used alone or in combination of two or more. A solvent is appropriately selected and used depending on the type and particle size of the polyester-based resin and other components added as needed. The amount of the solvent used is, based on 100 parts by weight of the total amount of the polyester-based resin and other components added as needed.
It is preferably from 50 to 5,000 parts by weight, more preferably from 120 to 1,000 parts by weight.

Catalysts usable in the production of the crystalline polyester resin as the binder resin include sodium,
Alkali metal compounds such as lithium, magnesium, alkaline earth metal compounds such as calcium, zinc, manganese,
Examples thereof include metal compounds such as antimony, titanium, tin, zirconium, and germanium, phosphite compounds, phosphoric acid compounds, and amine compounds. Specific examples include the following compounds.

For example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate,
Zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony,
Tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, triphenylphosphite,
Tris (2,4-di-t-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, triphenylamine and the like can be mentioned.

Dispersion suspension step: A dispersant is added to the dispersion obtained in the mixing step, and the mixture is stirred at 60 to 80 ° C. to prepare a dispersion suspension in which droplets of the crystalline resin are dispersed. .

The suspension droplets of the crystalline resin in the dispersion suspension obtained in the dispersion suspension step were prepared by mixing an aqueous medium and a liquid mixture (polymer liquid) containing at least a crystalline resin and a colorant. It is formed by applying a shearing force to a solution. At this time, by heating or using a crystalline resin dissolved in an organic solvent, particles can be formed by lowering the viscosity of the polymer liquid. The size of the suspension droplet (particle) of the crystalline resin is 1 to 20 μm as an average particle size.
m is preferable, 1 to 12 μm is more preferable, and 3 to 9 μm
m is more preferable, and 3 to 8 m is particularly preferable. Further, a dispersant may be used for stabilizing the dispersed suspension droplets and increasing the viscosity of the aqueous medium. As a dispersant,
The same dispersants as those used in the crosslinking step described below can be used. The amount of the dispersant used is preferably 1 to 40 parts by weight based on 100 parts by weight of water.

Examples of the disperser used for dispersing the suspension droplets include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. Further, the particles collide with a target mechanically or under a jet stream, and are pulverized to a desired toner particle size, then a crosslinking reaction is performed, and a particle size distribution is further sharpened through a classification process. In addition to the manufacturing method based on the pulverization method described above, a method using a disk or a multi-fluid nozzle to atomize the molten mixture into air to obtain a spherical toner can also be used.

Cross-linking step: A cross-linking step can be provided if necessary. Crosslinking is performed by adding a polymerization initiator to the suspension obtained by the dispersion suspension step and reacting at 60 to 100 ° C. By providing the crosslinking step, the elasticity of the toner can be controlled, so that the offset resistance and the fixed image strength can be improved.

When the binder resin is a crystalline polyester resin, a radical reaction is caused in the crystalline resin to introduce a crosslinked structure. As a polymerization initiator, for example, t-butylperoxy-2-ethylhexaene is used. Noate, cumyl perpivalate, t-butyl peroxy laurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2 , 2'-azobisisobutyronitrile,
2,2′-azobis (2-methylbutyronitrile),
2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3, 3,5-trimethylcyclohexane,
1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl)
Cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, 1,3 -Bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-
Di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, Di-t-butylperoxy α-methyl succinate, di-t-butylperoxydimethyl glutarate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, 2,5-dimethyl -2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylperoxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t -Butylperoxy) silane and the like. These may be used alone or in combination of two or more. The amount of the polymerization initiator to be used depends on the amount of the crystalline polyester resin 10
It is preferably 0.1 to 2 parts by weight with respect to 0 parts by weight.

Examples of the dispersant used in the suspension polymerization include water-soluble polymers such as polyvinyl alcohol, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate , Sodium octadecyl sulfate, sodium oleate, sodium lauryl sulfate,
Anionic surfactants such as potassium stearate; laurylamine acetate, stearylamine acetate,
Cationic surfactants such as lauryl trimethyl ammonium chloride; zwitterionic surfactants such as lauryl dimethylamine oxide; nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine Surfactants such as tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate,
Inorganic salts (inorganic compounds) such as barium carbonate; and the like.

When an inorganic compound is used as a dispersant,
A commercially available product may be used as it is, but an embodiment in which fine particles of an inorganic compound are produced in a dispersion medium may be employed for the purpose of obtaining fine particles. The dispersant is preferably used in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the binder resin.

The crosslinked structure introduced by the crystalline polyester resin is such that at least one unsaturated site inside the polyester chain reacts with at least one reactive site inside the second polyester chain to form a crosslinked unit. (First mechanism). The formation of cross-linked structures between chains produces large, high molecular weight molecules, which ultimately form a gel. As a second mechanism, a crosslinked structure is formed by a reaction between the insides of the same polyester chain. For the purpose of controlling the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like may be added.

Solvent removal step: 2 to 50 times (volume basis) water is added to the dispersion suspension after the dispersion suspension step or the cross-linking step, and the water washing is repeated to prepare a mixture of water and toner particles. . Thereafter, the water is evaporated using a freeze-drying method or the like, and the toner particles of the present invention are manufactured. In addition, in order to remove excess dispersant, a substance that reacts with and can remove the dispersant during washing with water (an acidic solution such as hydrochloric acid) may be added.

The toner particles can be made spherical by appropriately selecting the manufacturing conditions. When the toner particles have a spherical shape, fluidity can be improved and power consumption after transfer can be improved, and the fixing temperature can be reduced, and the amount of untransferred toner remaining on the photoconductor after transfer can be reduced.

{2. External Additive—The toner of the present invention may be composed of only the toner particles described above, but may be subjected to an external additive treatment such as a fluidizing agent or an auxiliary agent on the surface of the toner particles. As the external additive, there are inorganic fine particles and organic fine particles, and as the inorganic fine particles, for example, silica, alumina,
Titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, carbon black, wollastonite, cerium chloride,
Examples include chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, and silicon nitride. Among them, silica and titanium oxide are preferable, and silica fine particles subjected to hydrophobic treatment are particularly preferable.

The inorganic fine particles are generally used for the purpose of improving fluidity. As the primary particle diameter of the inorganic fine particles,
The amount is preferably from 1 to 1000 nm, and the amount of addition is preferably from 0.01 to 20 parts by weight, more preferably from 0.03 to 10 parts by weight, based on 100 parts by weight of the toner.

The organic fine particles include, for example, fluorocarbon resins such as polycarbonate, polystyrene, polymethyl methacrylate and polytetrafluoroethylene, and silicone resins. Organic fine particles are generally used for the purpose of improving cleaning properties and transfer properties.
The amount of the organic fine particles to be added is preferably 0.01 to 20 parts by weight based on 100 parts by weight of the toner particles.
-10 parts by weight is more preferred.

In the present invention, on the surface of the toner particles,
Further, a chargeable substance may be chemically or physically attached. In addition, fine particles such as metals, metal oxides, metal salts, ceramics, resins, and carbon black are charged,
An external additive may be added for the purpose of improving conductivity, powder fluidity, lubricity, and the like.

When an external additive is added, the external additive may be added to the toner particles and mixed. The mixing can be performed by, for example, a V-type blender or a Henschel mixer. Further, if necessary, coarse particles of toner and aggregates of external additives are removed by using a vibration sieving machine, a wind sieving machine, an ultrasonic sieving machine or the like.

The melting point of the toner of the present invention is from 50 to 120 ° C., preferably from 60 to 120 ° C., and more preferably from 65 to 110 ° C. If the melting point is lower than 50 ° C., there is a case where the storage stability of the toner and the storage stability of the sample after fixing may be concerned. On the other hand, if the temperature is higher than 120 ° C., sufficient low-temperature fixability cannot be secured.

The melting point of the toner can be determined as the melting peak temperature of the input compensation differential scanning calorimetry shown in JIS K-7121. Note that a crystalline resin may have a plurality of melting peaks, and the maximum peak is regarded as the melting point.

It is desired that the electrostatic charge developing toner of the present invention has sufficient hardness at normal temperature. Specifically, the dynamic viscoelasticity is such that at an angular frequency of 1 rad / sec and 30 ° C., the storage elastic modulus G _L (30) is 1 × 10 ⁶ Pa or more, and the loss elastic modulus G _N (30) is 1 It is desirable that the pressure be at least 10 ⁶ Pa. Incidentally, the storage elastic modulus G _L and the loss modulus G _N has its details are specified in JIS K-6900.

At an angular frequency of 1 rad / sec and 30 ° C., if the storage elastic modulus G _L (30) is less than 1 × 10 ⁶ Pa or the loss elastic modulus G _N (30) is less than 1 × 10 ⁶ Pa. When mixed with a carrier in a developing machine, toner particles are deformed by pressure or shear force received from the carrier,
In some cases, stable charge development characteristics cannot be maintained. Further, when the toner on the latent image carrier (photoconductor) is cleaned, the toner may be deformed by the shearing force received from the cleaning blade, resulting in poor cleaning. When the storage elastic modulus G _L (30) and the loss elastic modulus G _N (30) are within the above ranges at the angular frequency of 1 rad / sec and 30 ° C., the characteristics at the time of fixing even when used in a high-speed electrophotographic apparatus. Is stable and preferred.

Further, the toner for electrostatic charge development of the present invention
When the variation of the value of the storage modulus G _L and the loss modulus G _N due to a temperature change, which increased the 2 digits or more to become the temperature of the zone (10 ° C. temperature in the temperature range of 10 ° C., G _L and It is preferable to have a temperature section in which the value of G _N changes to a value of 1/100 or less. The storage modulus G _L and the loss modulus G _N is a no section of the temperature, the fixing temperature is increased, as a result, fixed at a low temperature, reducing the energy consumption of the fixing step, the fixing latitude May be insufficient to widen.

{B. Developer The toner of the present invention may be used as either a one-component developer composed of only the toner or a two-component developer further containing a carrier, but may be used as a two-component developer. Is preferred. In particular, it is preferable to use as a two-component developer in combination with a carrier coated with a resin. By applying a resin coating to the carrier, it is possible to improve background contamination and density unevenness resulting from rising of charge, deterioration of charge distribution, and decrease in charge amount due to reduction in particle size of the toner.

When the toner of the present invention is used as a one-component developer containing magnetic powder, the magnetic powder to be contained may be a ferromagnetic metal such as cobalt, iron or nickel;
Known magnetic materials such as alloys or oxides of metals such as cobalt, iron, nickel, aluminum, lead, magnesium, zinc, and manganese;

<1. Carrier> When the toner of the present invention is used as a two-component developer, the carrier may be a carrier in which the surface of a core material such as iron powder, ferrite, magnetite, etc. is coated with a resin, or a melt-kneading method and a polymerization method. Resin-dispersed carriers, and carriers whose surfaces are coated with a resin. Further, the coating layer of the carrier used in the present invention may be selected from any resin that can be used in the art, and the resin may be used alone or in combination of two or more.

Typical resins used as the matrix resin of the carrier include polyolefin resins such as polyethylene and polypropylene; polyvinyl resins such as polystyrene, acrylic resin, polyacrylonitrile and polyvinyl alcohol; styrene-acrylic acid copolymer; Silicone resin, fluororesin, polyester, polyurethane, polycarbonate, phenolic resin, amino resin,
Melamine resin, urea resin, polyamide resin, epoxy resin, and the like can be given.

The particle size of the carrier is preferably 120 μm or less as a volume average particle size,
100 μm is more preferable, and 20 to 60 μm is further preferable.

<2. Method for Producing Developer> The developer of the present invention for forming a full-color image is a two-component developer produced by mixing the toner for electrostatic charge development of the present invention and a carrier. For mixing, a turbula mixer, a V-type blender, or the like can be used. The mixing ratio of the toner and the carrier is generally 0.5 to 15% by weight as a toner concentration with respect to the total mass, and preferably 1 to 13% by weight in consideration of developability and transportability.
When the toner concentration is less than 0.5% by weight, the solid portion becomes rough due to a decrease in the toner conveyance amount, the character portion is blurred,
In some cases, adverse effects on image quality, such as deterioration of halftone density reproduction, may occur. On the other hand, if the toner concentration exceeds 15% by weight, an increase in the amount of transported toner causes defective transport such as blowing out of the toner, dropping of the toner, and erosion. Poor charging may occur such as generation of toner.

{C. Image Forming Method≫The image forming method of the present invention comprises developing at least the electrostatic latent image formed on the surface of the latent image carrier using a developer layer formed on the surface of the developer carrier, A developing step of obtaining a toner image on the surface of the latent image carrier, a transferring step of transferring the toner image to the surface of the transfer-receiving material to obtain a transferred image, and a fixing step of fixing the transferred image to obtain a fixed image. A full-color image forming method, wherein the developer contains at least a toner composed of toner particles composed of a colorant and a binder resin having a crystalline resin as a main component, and has a melting point of the toner. Is 50 ~
120 ° C., wherein the crystalline size of the crystalline resin in the fixed image is 3 μm or less on average.

In the image forming method of the present invention, each of the steps can use a known one.
What is generally called an electrophotographic photosensitive member or a dielectric recording member can be used as the latent image carrier. In the case of an electrophotographic photosensitive member, for example, after being uniformly charged by a corotron charger or a contact charger, exposure is performed to form an electrostatic latent image. Thereafter, a latent image is developed by contacting or approaching a developer carrier such as a developing roll having a surface of a developer layer formed thereon to obtain a toner image. The formed toner image is transferred to the surface of a transfer material such as paper by a corotron charger or a contact charger, and is fixed on the surface of the transfer material by a fixing device. As the fixing device, a pressure fixing method using only a pressure roll at room temperature, a contact heating type fixing method using a heating roll, an oven fixing method using oven heating, a flash fixing method using a xenon lamp,
A non-contact fixing method such as an electromagnetic fixing method using a microwave or a solvent fixing method using a solvent vapor may be used, but a heat fixing method is preferable from the viewpoint of reliability and safety, and a contact fixing device is preferably used from the viewpoint of thermal efficiency. It is preferred to use. Here, the contact-type fixing device refers to a fixing device of a method of fixing a transfer image on a transfer material by pressing a transfer material on which a transfer image is formed on a fixing member such as a fixing roll. Known contact-type fixing devices can be widely used. As the pressure contact method, a transfer material on which a transfer image is formed is passed between two contacting rolls, or between a contacting roll and a belt, and is transferred at a nip region of a roll-roll or a roll-belt. For example, a method of pressing and fixing an image may be used.

FIG. 1 is a schematic configuration diagram of an image forming apparatus for explaining an image forming mechanism according to the image forming method of the present invention. The image forming apparatus shown in FIG. 1 includes a photoconductor (latent image carrier) 10 which is an electrophotographic photoconductor, a charging roll 12 which is a charging means of a contact charging system, a laser exposure optical system 14, and a development using powder toner. Device 16, transfer roll 18, static eliminator 1
9, a cleaning blade 20 as a mechanical cleaning means and a fixing roll 22 are provided.

The image forming mechanism according to the image forming method of the present invention will be described below by taking the image forming apparatus shown in FIG. 1 as an example. First, the surface of the photoconductor 10 is uniformly charged by the charging roll 12. The laser exposure optical system 14 irradiates light to a portion other than the image area, removes the charged electric charge in the light-irradiated area, and forms an electrostatic latent image with the electric charge left in the image area. In the developing device 16 using the powder toner, a toner charged to the opposite polarity to the electrostatic latent image is attached to the electrostatic latent image to form a visible image (toner image) (developing step). Next, the transfer material 17 is passed between the photoreceptor 10 on which the toner image is formed and the transfer roll 18, and the toner image is transferred onto the transfer material in a superimposed manner (transfer step). The transferred toner image moves to the two fixing rolls 22 in contact with each other, passes through the nip portion between the two fixing rolls 22, and is fixed by heat and / or pressure to form an image (fixing step).

On the other hand, the latent image charges on the surface of the photoreceptor 10 after the transfer are eliminated by the electric charge reduction device 19. Further, the toner (residual toner) on the surface of the photoconductor 10 remaining without being transferred is removed by the cleaning blade 20. An image is formed continuously by repeating a series of processes from the charging to the removal of the residual toner.

Here, the mechanical cleaning means is
This is to remove toner, paper dust, dust and the like adhering directly to the surface of the photoconductor 10 and remove the toner, paper dust, dust, and the like. Things can be applied.

FIG. 2 is a schematic diagram showing a specific example of an image forming apparatus for explaining a full-color image forming mechanism according to the image forming method of the present invention. In FIG.
Denotes a photosensitive drum as a latent image carrier, 102 denotes a transfer belt as an intermediate transfer member, and the transfer belt 102
The belt is stretched by belt rollers 121, 123 and 124 and a backup roller 122, and is disposed so as to be in contact with the surface of the photosensitive drum 101.

Around the photosensitive drum 101, developing units 105, 106, 107 corresponding to respective colors of BK (black), Y (yellow), M (magenta) and C (cyan)
A conductive roller 1 is provided at a position facing the photosensitive drum 101 with the transfer belt 102 interposed therebetween.
25 are provided.

Around the transfer belt 102, there are a bias roller 103 as a transfer electrode, an electrode roller 126, and a peeling claw 1.
13, belt cleaner 109, feed roller 143
Are arranged. The bias roller 103 includes a cleaning blade 131, and the transfer belt 102
Is disposed at a position facing the backup roller 122 with the. The electrode roller 126 is provided around the backup roller 122 and inside the transfer belt 102.
Are arranged.

A peeling claw 113 is provided between the backup roller 122 and the belt roller 124. A belt cleaner 109 is provided at a position facing the belt roller 124 with the transfer belt 102 interposed therebetween.

In the vicinity of the bias roller 103, there are provided a feed roller 143, a tray 104 for supplying a sheet 141 'from a sheet bundle 141 made of sheets to be transferred, and a pickup roller 142.

A full-color image forming mechanism according to the image forming method of the present invention will be described below with reference to the image forming apparatus shown in FIG. As the photosensitive drum 101 rotates in the direction of arrow A, its surface is uniformly charged by a charging device (not shown). An electrostatic latent image of the first color is formed on the charged surface of the photosensitive drum 101 by an image writing unit (not shown) such as a laser writing device. This electrostatic latent image is developed by any one of the developing devices, and a toner image T is formed. For example, if the electrostatic latent image written on the photosensitive drum 101 corresponds to black image information, the electrostatic latent image is developed by the developing device 105 containing black (BK) toner.
, And a black toner image T is formed on the surface of the photosensitive drum 101.

In the case of forming a monochromatic image, the toner image T moves to the primary transfer portion where the conductive roller 125 is disposed by the rotation of the photosensitive drum 101, and the toner image T has the opposite polarity to the toner image T from the conductive roller 125. By applying an electric field, the toner image T is electrostatically primarily transferred onto the surface of the transfer belt 102. Primary transferred unfixed toner image T
Is moved by the transfer belt 102 circling in the B direction,
The toner image T is secondary-transferred between the backup roller 122 and the bias roller 103 for applying a transfer voltage having a polarity opposite to the charge polarity of the toner to the sheet 141 ′ sent from the tray 104 by the pickup roller and the feed roller 143. You. After that, the toner image T is secondarily transferred to the sheet 141 ', and is fixed by a fixing device (not shown) to form an image.

On the other hand, when forming a full-color image in which a plurality of colors are superimposed, the steps of forming the toner image T on the surface of the photosensitive drum 101 and the primary transfer of the toner image T are repeated by the number of colors. The final color toner image T
Until the first transfer is performed on the transfer belt 102, the peeling claw 113 and the belt cleaner 109 are separated from the transfer belt 102.

For example, when a full-color image is formed by superimposing four color toner images T, the photosensitive drum 101
Black, yellow, magenta, and cyan toner images T are formed on the front surface every one rotation, and these toner images T are sequentially primary-transferred to the transfer belt 102 sequentially.

On the other hand, the transfer belt 102 circulates in the direction B in the same cycle as the photosensitive drum 101 while holding the first primary-transferred black toner image T on the surface of the transfer belt 102. Each time, the yellow, magenta and cyan toner images T are transferred so as to be superimposed on the black toner image T. In this way, toner images of four colors are sequentially formed and are superimposed on the transfer belt 102, so that a full-color image is formed on the surface of the transfer belt 102 before being transferred onto the paper 141 '. Then, the paper 141 '
The full-color image is secondary-transferred and fixed by a fixing device (not shown) to form a full-color image.

The full-color image obtained by the above-described full-color image forming method has an average crystal size (crystal diameter) of the crystalline resin in the fixed image of 3 μm or less, preferably 1 μm or less.
m or less. The crystal size of the crystalline resin can be measured with a polarizing microscope. In the present invention, the "average"
Means, for example, measuring the size of each of 100 crystals,
It means the average of these values.

The crystal size of the crystalline resin is 3 μm on average.
If it is larger, sufficient transparency cannot be obtained due to an increase in the scattering component.
Not only the P transmittance but also the density is reduced, and the reproducible color gamut is narrowed. Further, when images are superimposed in full color, color reproducibility becomes insufficient. In order to reduce the average crystal size after fixing to 3 μm or less, any method may be used. However, as described above, by adding a crystal nucleating agent to the crystalline resin of the toner particles constituting the toner, the crystal is formed. The crystal size of the conductive resin can be reduced.

[0097]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 [Production of Toner] A two-necked flask dried by heating was charged with 10 mol parts of dimethyl fumarate and 90 m of dimethyl sebacate.
ol part and ethylene glycol (3.5 m for the acid component)
ol times) and Ti (OBu) ₄ (0.01
mol part), the air in the container was replaced with nitrogen gas by a decompression operation to form an inert atmosphere, and the mixture was refluxed at 180 ° C. for 5 hours by mechanical stirring. Thereafter, excess ethylene glycol was removed by distillation under reduced pressure,
C. and gradually stirred for 2 hours. When the mixture became viscous, it was air-cooled to stop the reaction. Before the product solidifies, tetrahydrofuran (hereinafter referred to as "T
HF ". ) Was added, and the catalyst residue was removed with a pressure filtration device. The reprecipitate was recovered and purified using THF / MeOH, and dried under reduced pressure to obtain a polyester resin (1).

75 parts by weight of the obtained polyester resin (1) and Cyan pigment (CI Pigment Blue 1)
5: 3) A dispersion was prepared by dispersing 3.4 parts by weight, 0.5 parts by weight of dibenzylidene sorbitol as a nucleating agent, and 75 parts by weight of ethyl acetate by a sand mill (mixing step).

Carboxymethylcellulose 3.0% by weight
20 parts by weight of calcium carbonate was added to 300 parts by weight of the aqueous solution, and nitrogen bubbling was performed. 100 parts by weight of the dispersion obtained in the mixing step is added thereto at 50 ° C.
The mixture was stirred and suspended with a Turrax at 50 ° C. and 10,000 rpm for 3 minutes to obtain a suspension solution (dispersion suspension step).

Next, a solution prepared by dissolving 1.5 parts by weight of 2,2′-azobisisobutyronitrile (polymerization initiator) in 22 parts by weight of toluene was added to the suspension while heating and stirring under a nitrogen stream. And reacted at 80 ° C. for 1.0 hour (crosslinking step). While continuing to stir, 40
The suspension polymerization was completed by cooling to ℃, and a crosslinked particle dispersion was obtained.

About 5 times the amount of water was added to the obtained crosslinked particle dispersion, calcium carbonate was dissolved with an excessive amount of hydrochloric acid, and the resultant was repeatedly washed with water. Thus, a mixture of water and a toner was obtained. Finally, water was evaporated under reduced pressure and freeze drying to obtain cyan toner (1) for electrostatic charge development (solvent removal step).

The obtained cyan toner (1) for electrostatic charge development was subjected to a Coulter counter [TA-II].
The volume average particle diameter measured using a mold (aperture diameter: 50 μm; manufactured by Coulter) was 7.4 μm, and the number average particle diameter was 7.4 μm.

Obtained cyan toner for electrostatic charge development (1)
Was measured using a thermal analyzer of a differential scanning calorimeter (manufactured by Mac Science Corporation: DSC3110, thermal analysis system 001) (hereinafter abbreviated as “DSC”). The measurement was performed from room temperature to 150 ° C. at a rate of 10 ° C./min, and the melting point was obtained by analyzing according to JIS standards.
As a result of the measurement, the melting point was 72 ° C.

[Production of Carrier] The following components except ferrite particles were dispersed with a stirrer for 10 minutes to prepare a coating layer forming solution. Further, this coating layer forming liquid and ferrite particles were filled in a vacuum degassing type kneader, and stirred at a temperature of 60 ° C. for 30 minutes. Thereafter, toluene was distilled off under reduced pressure to obtain a carrier on which a coating layer was formed. (However, carbon black was diluted with toluene in a perfluorooctylethyl acrylate-methyl methacrylate copolymer as a carrier resin and dispersed in a sand mill.)

Ferrite particles (average particle size: 35 μm)
m): 100 parts by weight, toluene: 14 parts by weight, perfluorooctylethyl acrylate-methyl methacrylate copolymer (critical surface tension 24 dyn / c)
m): 1.6 parts by weight, carbon black (trade name; VXC-72, manufactured by Cabot Corporation, resistance 10 ⁸ Ωcm or less): 0.12 parts by weight, crosslinked melamine resin particles (average particle size: 0.3 μm) , Toluene insoluble): 0.3 parts by weight

[Production of Developer] A developer (1) was prepared by mixing 4.0 parts by weight of the toner with 95 parts by weight of the carrier using a V-type mixer (V-type blender).

Example 2 Crystal nucleating agents were 1,3; 2,4-
With the exception of replacing it with dimethyldibenzylidenesorbitol,
Cyan toner for electrostatic charge development (2) in the same manner as in Example 1.
Was prepared, and the volume average particle diameter and the melting point were measured in the same manner as in Example 1. As a result, 6.5 μm and 72 ° C. were obtained, respectively.
Met. Thereafter, the developer (2) was prepared in the same manner as in Example 1.
I got

Example 3 A crystal nucleating agent was silica fine powder (A
300; manufactured by Nippon Aerosil Co., Ltd.) A cyan toner (3) for electrostatic charge development was prepared in the same manner as in Example 1 except that the weight was changed to 5.0 parts by weight. Of 7.6 μm and 7
2 ° C. Thereafter, a developer (3) was obtained in the same manner as in Example 1.

Example 4 A cyan toner (4) for electrostatic charge development was prepared in the same manner as in Example 1, except that dimethyl sebacate was replaced with dimethyl succinate and ethylene glycol was replaced with butanediol, respectively. When the volume average particle diameter and the melting point were measured in the same manner as in Example 1, it was 7.2 μm and 92 ° C., respectively. Then, Example 1
In the same manner as in the above, a developer (4) was obtained.

Example 5 Cyan pigment (CI Pigment Blue 15: 3) was replaced with Magenta pigment (C.I.
I. Pigment Red 57: 1), except that a magenta toner for electrostatic charge development (5) was prepared in the same manner as in Example 1 and the volume average particle diameter and the melting point were measured in the same manner as in Example 1. 7.3 μm and 72 ° C. Thereafter, a developer (5) was obtained in the same manner as in Example 1.

Example 6 The procedure was carried out except that 3.4 parts by weight of Cyan pigment (CI Pigment Blue 15: 3) was replaced by 4.5 parts by weight of Yellow pigment (CI Pigment Yellow 17). A yellow toner (6) for electrostatic charge development was prepared in the same manner as in Example 1, and the volume average particle diameter and the melting point were measured in the same manner as in Example 1.
m and 72 ° C. Thereafter, a developer (6) was obtained in the same manner as in Example 1.

Comparative Example 1 A cyan toner (7) for electrostatic charge development was prepared and a developer was prepared in the same manner as in Example 1 except that the crystal nucleating agent was removed. The diameter and melting point were measured to be 7.6 μm and 72 ° C., respectively. Thereafter, a developer (7) was obtained in the same manner as in Example 1.

Comparative Example 2 A magenta toner for electrostatic charge development (8) was prepared in the same manner as in Example 5 except that the nucleating agent was omitted.
Was prepared, and the volume average particle diameter and the melting point were measured in the same manner as in Example 1. As a result, they were 7.5 μm and 72 ° C., respectively. Thereafter, a developer (8) was obtained in the same manner as in Example 1.

Comparative Example 3 A yellow toner for electrostatic charge development (9) was prepared in the same manner as in Example 6 except that the nucleating agent was omitted.
Was prepared, and the volume average particle diameter and the melting point were measured in the same manner as in Example 1. As a result, they were 7.5 μm and 72 ° C., respectively. Thereafter, a developer (9) was obtained in the same manner as in Example 1.

Comparative Example 4 Linear polyester resin (linear polyester obtained from terephthalic acid / bisphenol A / ethylene oxide adduct / cyclohexanedimethanol: glass transition temperature (Tg) = 62 ° C., number average molecular weight (Mn) ) = 4,000, weight average molecular weight (Mw) =
35,000, acid value = 12, hydroxyl value = 25) 75 parts by weight and cyan pigment (CI Pigment Blue 15:
3) 3.4 parts by weight and 75 parts by weight of ethyl acetate were dispersed by a sand mill to prepare a dispersion (mixing step).
Carboxymethylcellulose 1.0% by weight aqueous solution 300
20 parts by weight of calcium carbonate was added to parts by weight, and nitrogen bubbling was performed. The dispersion 1 obtained in the mixing step
00 parts by weight at 50 ° C., and Ultra Turrax
The suspension was stirred at 50 ° C. and 10,000 rpm for 3 minutes to obtain a suspension solution (dispersion suspension step).

Then, about 5 times the amount of water was added to the particle dispersion obtained by cooling the suspension solution to 40 ° C. in a water bath, calcium carbonate was dissolved with an excess amount of hydrochloric acid, and the water washing was repeated. Thus, a mixture of water and toner was obtained. Finally, water was evaporated under reduced pressure and freeze drying to obtain a cyan toner (10) for electrostatic charge development (solvent removal step). The volume average particle diameter of the cyan toner for electrostatic charge development (10) was measured in the same manner as in Example 1, and it was 7.2 μm. Thereafter, a developer (10) was obtained in the same manner as in Example 1.

Comparative Example 5 Cyan pigment (CI Pigment Blue 15: 3) was replaced with Magenta pigment (C.I.
I. Pigment Red 57: 1), and a magenta toner for electrostatic charge development (11) was prepared in the same manner as in Comparative Example 4. The volume average particle diameter was measured in the same manner as in Comparative Example 4, and found to be 7.3 μm. Met. Thereafter, a developer (11) was obtained in the same manner as in Example 1.

Comparative Example 6 Comparative Example was conducted except that 3.4 parts by weight of Cyan pigment (CI Pigment Blue 15: 3) was replaced with 4.5 parts by weight of Yellow pigment (CI Pigment Yellow 17). In the same manner as in Example 4, yellow toner (12) for electrostatic charge development was obtained. When the volume average particle diameter was measured in the same manner as in Comparative Example 4, it was 7.3 μm. Thereafter, a developer (12) was obtained in the same manner as in Example 1.

Examples 1 to 6 and Comparative Example 1 obtained above
Using the developers (1) to (12) obtained in the above-described Examples 6 to 6, image formation and various evaluations were performed. The specific evaluation items and their details are as follows.

<Evaluation of Fixing> Examples 1 to 6 and Comparative Example 1
The developers (1) to (12) obtained by the methods (1) to (6) were
color 935 full color copier (manufactured by Fuji Xerox Co., Ltd., modified so that fixing conditions can be adjusted)
, And a solid fixed image was formed on a fixing bench using a fixing device under the following fixing conditions.
Table 1 shows the results.

[0122] - fixing conditions - toner image: Solid images (40 mm × 50 mm), - toner amount: 0.65 mg / cm ² (monochrome), - Paper: manufactured by Fuji Xerox Co., a color copy paper (J
・ Conveying speed: 160 mm / sec ・ Release agent: silicone oil (silicone resin), coating amount 1.6 × 10 ⁻³ mg / cm ²・ Fixing temperature: 120 ° C. and 160 ° C.

When there is no problem such as image loss due to offset in the fixed image after fixing, ○, when there is a slight change but there is no problem in practical use, △ A certain level was marked as x.

<Measurement of Crystal Size in Fixed Image> The fixed image was embedded, cut with a microtome while cooling with liquid nitrogen, and the sample was dyed by holding it over ruthenium tetroxide vapor to prepare a sample. This sample was placed on a polarizing microscope (L
(manufactured by Aica Co., Ltd.), and the average size of 100 crystals was taken as the crystal size.

<Measurement of Image Density and Color Gamut>
6 and Comparative Examples 1 to 3, images formed at a fixing temperature of 120 ° C. under the above fixing conditions, and Comparative Examples 4 to 6
The image density and color gamut of the image formed at a fixing temperature of 160 ° C. under the above fixing conditions were measured by X-rite.

[0126]

[Table 1]

Example 7 With the developer (5) as the lower layer and the developer (1) as the upper layer, the toner amount was 0.65 mg /
A solid image was formed in the same manner as in Example 1 so as to give a cm ² , and the crystal size was measured and the color gamut of the image was measured. However, the color gamut was measured for images formed with the fixing temperature at 120 ° C. (Examples 8 and 9 and Comparative Examples 7 to 9).
9).

(Example 8) The developer (6) was used as a lower layer and the developer (1) was used as an upper layer.
A solid image was formed in the same manner as in Example 1 so as to give a cm ² , and the crystal size was measured and the color gamut of the image was measured.

(Example 9) The developer (6) was used as a lower layer and the developer (5) was used as an upper layer.
A solid image was formed in the same manner as in Example 1 so as to give a cm ² , and the crystal size was measured and the color gamut of the image was measured.

(Comparative Example 7) The developer (8) was used as a lower layer and the developer (7) was used as an upper layer.
A solid image was formed in the same manner as in Example 1 so as to give a cm ² , and the crystal size was measured and the color gamut of the image was measured.

Comparative Example 8 The developer (9) was used as a lower layer, and the developer (7) was used as an upper layer.
A solid image was prepared in the same manner as in Example 1 so as to obtain cm ² , and the crystal size was measured and the color gamut of the image was measured.

(Comparative Example 9) With the developer (9) as the lower layer and the developer (8) as the upper layer, the toner amount was 0.65 mg / each.
A solid image was prepared in the same manner as in Example 1 so as to obtain cm ² , and the crystal size was measured and the color gamut of the image was measured.

Table 2 shows the measurement results of Examples 7 to 9 and Examples 7 to 9.

[0134]

[Table 2]

As is clear from the results shown in Tables 1 and 2, by using a crystalline resin having a low melting point as the binder resin, fixing can be performed without problems even at 120 ° C., and fixing can be performed at a lower temperature than conventional resins. it can. When the size of the crystalline resin in the fixed image is 1 μm or less on average, the color gamut can be widened. Furthermore, by reducing the light scattering component, it is possible to secure the same color gamut as the density reproduction and the improved color developing property of the conventional binder resin, and it is also possible to reproduce the secondary colors by superimposing images. By using a nucleating agent, the crystal size of the crystalline resin can be reduced to an average of 1 μm.
m or less.

[0136]

The use of the toner for electrostatic charge development of the present invention can improve the storability and blocking resistance without impairing the density, color developability, transparency and the like of a fixed image after fixing. Further, according to the image forming method of the present invention, it is possible to perform fixing at a lower temperature than before, and it is possible to greatly reduce energy in a fixing process and shorten a warm-up time. Further, there is no problem such as filming on the photoconductor (latent image carrier) or the carrier.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus for explaining an image forming mechanism according to an image forming method of the present invention.

FIG. 2 is a schematic configuration diagram showing a specific example of an image forming apparatus for explaining a full-color image forming mechanism according to the image forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Photoconductor 12 ... Charging roll 14 ... Laser exposure optical system 16 ... Developing device 18 ... Transfer roll 19 ... Static eliminator 20 ... Cleaning blade 22 ... Fixing roll

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Norihito Fukushima 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Takashi Imai 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (Reference) 2H005 AA01 AA21 EA03 EA05 FA02

Claims (4)

[Claims] At least an electrostatic latent image formed on a surface of a latent image carrier is developed using a layer of a developer formed on the surface of a developer carrier, and a toner is formed on the surface of the latent image carrier. A full-color image forming method comprising: a developing step of obtaining an image; a transferring step of transferring the toner image to a surface of a transfer-receiving material to obtain a transferred image; and a fixing step of fixing the transferred image to obtain a fixed image. The developer contains at least a toner composed of toner particles composed of a colorant and a binder resin containing a crystalline resin as a main component, and the toner has a melting point of 50 to 120 ° C.
Wherein the crystal size of the crystalline resin in the fixed image is 3 μm or less on average. 2. A full-color image obtained by the full-color image forming method according to claim 1. 3. A toner for use in a full-color image forming method according to claim 1, wherein the crystalline resin contains a nucleating agent. 4. A two-component developer comprising at least a carrier and a toner, wherein the toner is the toner for electrostatic charge development according to claim 3.