JP2001356519A - One-component developer and developing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one component developer which prevents wear of a developer carrying body, has enough charge amount and enough carrying property even on a worn developer carrying body and provides high image density free from defects such as thinning and voids and to provide a method for developing using the one component developer. SOLUTION: The developer contains at least an inorganic particle external additive, in which the proportion of the free inorganic particle additives to the whole amount of the inorganic particle external additives is <=5 wt.%. The developer is used for the method for one component development.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing method used in an electrophotographic copying machine, a printer and an electrostatic recording apparatus, and more particularly, to image characteristics such as image density, resolution and gradation, and repetition. The present invention relates to a one-component developer and a one-component developing method having excellent durability in use.

[0002]

2. Description of the Related Art As a developing method used in an electrophotographic copying machine or an electrostatic recording apparatus, a developer is transported by a transport member, and an electrostatic latent image formed on a photoreceptor is visualized by the developer. Methods of imaging are well known. In this developing method, a one-component developer composed of only a toner or a two-component developer composed of a toner and a carrier is generally used. In recent years, various developing methods using a one-component developer consisting of toner alone have been proposed because of the advantage that the apparatus can be downsized and maintenance is easy (US Pat. No. 3,909,258, US Pat. etc).

In this developing method, it is important to form a thin developer layer having a uniform thickness and a uniform charge amount on the developer carrier. For this reason, the developer layer is provided on the developer carrier. A regulating member is provided which is in contact therewith. However, in this developing method, since the regulating member strongly presses the developer layer against the developer carrying member, there has been a problem that the developer carrying member is worn due to repeated actual photographing and the developing characteristics are significantly deteriorated. Specifically, the image density is reduced, the image density is reduced, blurring occurs, and a character portion is hollow due to an insufficient charging ability to the developer layer or an insufficient transporting ability of the developer.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent abrasion of a developer carrier and to provide a sufficient charge amount and sufficient transportability even for the worn developer carrier. , High image density, no defects such as blurring or voids,
An object of the present invention is to provide a one-component developer excellent in resolution and gradation. Another object of the present invention is to provide a developing method using a one-component developer having such excellent characteristics. Still another object of the present invention is to provide a developing method by a reversal developing method in which the polarity of a developer is the same as the polarity of an electrostatic latent image on a photoreceptor.

[0005]

Means for Solving the Problems The present inventors have studied various factors in order to solve such a problem, and found that the inorganic particle external additive in a free state among the inorganic particle external additives contained in the developer was freed. It has been found that the degree of the influence has an effect on the progress of wear of the developer carrying member, and that the above problems can be solved by reducing the amount of free inorganic particle external additives, thereby achieving the present invention. That is, the gist of the present invention is that, in a one-component developer comprising at least a colorant and a binder resin, the developer contains inorganic particles as an external additive, and free inorganic particles are contained with respect to the total amount of the inorganic particle external additive. A one-component developer, wherein the amount of the external additive is 5 wt% or less.

Another gist of the present invention is that a one-component developer is thinned by a regulating member which comes into contact with a developer carrier with a developer layer interposed therebetween to form a one-component developer layer. In the one-component developing method for developing the electrostatic latent image by supplying the developer layer to the latent image holding member, the developer is a one-component developer comprising at least a colorant and a binder resin, and the developer is an external developer. A one-component developer containing inorganic particles as an additive and having an amount of free inorganic particle external additives of 5 wt% or less with respect to the total amount of the inorganic particle external additives is used. In the developing method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The one-component developer of the present invention is a one-component developer comprising at least a colorant and a binder resin, wherein the developer contains inorganic particles as an external additive, and is free with respect to the total amount of the inorganic particle external additive. A developer characterized in that the amount of the external additive for inorganic particles is 5 wt% or less. Further, in the developing method of the present invention, the developer is formed into a one-component developer layer by regulating the thickness of the one-component developer with a regulating member contacting the developer carrier with the developer layer interposed therebetween. The present invention is applied to a developing method of supplying an agent layer to a latent image holding member to develop an electrostatic latent image.

[0008] In particular, the one-component developer of the present invention is not only in a state where the wear of the developer carrier has not progressed, but also when the abrasion progresses and the conventional one-component developer is used, the developing characteristics are remarkable. Even if the developer carrier deteriorates, sufficient image quality can be obtained without deteriorating the developing characteristics.

Here, the degree of wear of the developer carrier can be known from the surface roughness of the developer carrier. That is, it can be confirmed by comparing the surface roughness (Ra) of the developer carrying member with the initial value (Ra ¹ ) of the surface roughness of the developer carrying member. Specifically, (Ra / R
a ¹ ) It is calculated by the calculated value of X100. If this value is in the range of 70 to 100%, there is not much effect on the developing characteristics, but in the case of the developer carrier having this value of 70% or less, The development characteristics are significantly deteriorated. Even with the developer carrying member in such a state, if the one-component developer of the present invention is used, sufficient image quality can be achieved without deteriorating the developing characteristics. In the present invention, the lower limit of the degree of progress of wear of the developer carrier is not particularly limited,
If the wear has progressed remarkably, the image quality may be deteriorated. Therefore, the wear is usually 30% or more, preferably 40%.
With the developer carrier in the above state, the effects of the present invention can be sufficiently enjoyed. The measurement of the surface roughness of the developer carrying member in the present invention is carried out according to JIS B 0601-1982.
According to.

The one-component developer of the present invention comprises at least a colorant and a binder resin, and further contains inorganic fine particles as an external additive. Further, a charge control agent, a wax, and other additives can be included as needed. In the present invention, the amount of the inorganic particle external additive contained in the developer is 5 wt% or less, preferably 3 wt% or less, more preferably 2 wt% or less based on the total amount of the inorganic particle external additive.
% Is desirable. Here, the free inorganic fine particle external additive is one that exists without adhering to the developer, or that is easily detached from the developer because of its weak adhesion to the developer. The measurement is performed with a particle analyzer manufactured by Yokogawa Electric Corporation.
Specifically, the measurement is performed as follows. That is, the one-component developer of the present invention is sucked up by an aspirator using helium as a carrier gas, and is measured by a plasma emission analysis at a measurement unit. Since the free inorganic particle external additive does not emit light in synchronization with the emission of carbon atoms in the binder resin or the like, it is quantified by the emission intensity.

The inorganic particle external additive used in the present invention has a normal particle size, and preferably has a primary particle size of 30.
The inorganic particle external additive having a particle size of at least 50 nm is not more than 50%, more preferably 30% by weight, based on the total amount of the inorganic particle external additive contained in the developer.
% Is desirable. The primary particle diameter of the inorganic fine particle external additive is determined by collecting the inorganic fine particle external additive on a sample table at a density such that each particle can be distinguished, and observing the particles other than the particles clearly aggregated by observation with an electron microscope. The measurement is made with a population of 1000 particles. The particle size is determined by (projected area of particle / π) 1/2. When the inorganic particle external additive having a primary particle diameter of 30 nm or more among the inorganic particle external additives contained in the developer exceeds 50% by number with respect to the total amount of the inorganic particle external additive, particularly, the developer carrier is worn. When this is used, image defects such as a decrease in image density and blurring occur. This is presumed to be due to the fact that the inorganic fine particles having a relatively large particle size promote the abrasion of the developer carrier and reduce the efficiency of charging the developer by the regulating member in contact with the developer layer. You. The addition amount of the inorganic particle external additive is preferably from 0.3 to 5 parts by weight, more preferably from 0.5 to 4 parts by weight, based on 100 parts by weight of the developer before addition.

The inorganic particles used as the external additives include silica, alumina, titania, magnetite, ferrite, cerium oxide, strontium titanate, barium titanate, talc, talcites, silicon nitride, silicon carbide, and titanium nitride. And those obtained by subjecting them to a known hydrophobic treatment can be used. Of these, silica, alumina and titania are preferred, and silica is more preferred.
The hydrophobizing agent may be used by chemically fixing it to the surface of the external additive of inorganic particles using a coupling agent or the like, or may be used by physically fixing silicone oil or modified silicone oil. . The degree of hydrophobicity is preferably 10 or more, more preferably 20 or more. A so-called methanol titration method is used for measuring the degree of hydrophobicity. Further, the pH shown when these inorganic fine particle external additives are dispersed in water irrespective of the presence or absence of the hydrophobic treatment is not particularly limited, but is preferably in the range of 4 to 12.

Known methods can be used for adding the inorganic fine particle external additive without any limitation. For example, a mechanical fixing method represented by a Henschel mixer, a chemical mixer, a mechanofusion method, or a thermal fixing method represented by a surffusion method can be used.

As the binder resin used in the developer of the present invention, various known resins suitable for ordinary developers can be used. For example, styrene resin, vinyl chloride resin, rosin-modified maleic resin, phenol resin, epoxy resin, saturated polyester resin, unsaturated polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin , Ethylene-ethyl acrylate copolymer, xylene resin and polyvinyl butyral resin, and the like, but preferred resins for use in the present invention include:
Styrene resins, saturated or unsaturated polyester resins, epoxy resins and the like can be mentioned. These resins may be used alone or in combination. These resins are used as a non-crosslinked resin, a crosslinked resin, or a mixture thereof according to the fixing method.

Of these, the following styrene resins or polyester resins are preferred. As the styrene resin, polystyrene, polychlorostyrene, poly-α-
Methylstyrene, styrene-chlorostyrene copolymer,
Styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-
Vinyl acetate copolymer, styrene-maleic acid copolymer,
Styrene-acrylate copolymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, and styrene-phenyl acrylate Copolymers), styrene-methacrylate copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer) And styrene-phenyl methacrylate copolymer), styrene-α-methyl methyl acrylate copolymer, styrene-acrylonitrile-acrylate copolymer and the like. These styrene resins can be used as a crosslinked resin by copolymerizing a crosslinkable monomer as needed. As a method for producing the binder resin, there are bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, and the like, but any method can be used regardless of the polymerization method.

The polyester resin is a polycondensation of a divalent carboxylic acid monomer, a divalent alcohol monomer and, if necessary, a trivalent or higher polyvalent carboxylic acid monomer or a polyhydric alcohol monomer. Alternatively, it can be obtained by increasing the molecular weight by urethanization or a crosslinking reaction. As a dihydric alcohol monomer,
Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,
3-propylene glycol, 1,4-butanediol,
Examples include diols such as neopentyl glycol and 1,4-butenediol, etherified bisphenols such as bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylene bisphenol A, and other dihydric alcohol monomers. . The divalent carboxylic acid monomer is mainly composed of isophthalic acid, terephthalic acid, adipic acid, sebacic acid, diphenic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, and anhydrides or lower alkyl esters of these acids. Is mentioned. Examples of the trivalent or higher polycarboxylic acid include trimellitic acid, cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, butanetricarboxylic acid, hexanetricarboxylic acid, octanetetracarboxylic acid, anhydrides of these acids, and others. Trihydric or higher polyhydric alcohol monomers include trimethylolethane,
Trimethylolpropane, glycerin, pentaerythritol and the like.

The colorant used in the present invention is not particularly limited. For example, carbon black,
Lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine dye, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo dye, disazo Any known dyes and pigments, such as dyes and condensed azo dyes, can be used alone or in combination. No particular limitation is imposed on the full-color toner as long as known dyes and pigments are used.For example, yellow is benzidine yellow, monoazo dye or pigment, condensed azo dye or magenta is quinacridone, rhodamine dye or monoazo dye. It is preferable to use phthalocyanine blue for cyan and carbon black for black. The colorant is used in an amount of usually 1 to 20 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The developer of the present invention may have a magnetic powder as a coloring agent. Generally, magnetic particles of black or brown color are used as the colorant. Known magnetic particles used in the present invention can be used without particular limitation,
For example, it is a ferromagnetic substance showing ferrimagnetism or ferromagnetism at a use environment temperature (around 0 ° C. to 60 ° C.) of a copying machine or the like, for example, magnetite (Fe ₃ O ₄ ), maghematite (γ-Fe ₂ O ₃ ), an intermediate between magnetite and maghematite, ferrite (M _x Fe _3-x O ₄ ; where M is Mn,
Spinel ferrites such as Fe, Co, Ni, Cu, Mg, Zn, Cd, etc. or mixed crystal thereof, and BaO.6Fe
_{2 O 3, SrO · 6Fe 2} O 3 or the like of the hexagonal ferrite, Y ₃ F
_{e 5 O 12, Sm 3 Fe} 5 O garnet-type oxides such as _12, C
rutile oxide such as rO ₂ , Fe, Mn, Ni, Co,
Among metals such as Cr and other ferromagnetic alloys, 0 ° C to 6 ° C
Those exhibiting ferromagnetism and ferrimagnetism at around 0 ° C. are mentioned. Among them, magnetite, maghematite, intermediate particles of magnetite and maghematite and the like have an average particle size of 3 μm or less,
More preferably, fine particles of about 0.05 to 1 μm are preferable in terms of performance and cost. Further, the above magnetic fine particles are not limited to being used alone, and two or more kinds can be used in combination.
The shape of the magnetic powder can be used regardless of hexahedron, octahedron, irregular shape, polyhedron, and sphere. These magnetic powders are generally used in an amount of 0.1 to 150 parts by weight, preferably 30 to 120 parts by weight, based on 100 parts by weight of the binder resin.

When the developer contains a charge control agent, known charge control agents can be used. Examples of the charge control agent for a negatively chargeable developer include a chromium azo complex dye and iron. Azo complex dyes, cobalt azo complex dyes, chromium-zinc-aluminum-boron complexes or salt compounds of salicylic acid or its derivatives, chromium-zinc-aluminum-boron complexes or salt compounds of naphtholic acid or its derivatives, chromium of benzylic acid or its derivatives A zinc / aluminum / boron complex or salt compound, a long-chain alkyl carboxylate, a long-chain alkyl sulfonate, or the like can be used. Examples of the charge control agent for a positively-charged developer include a nigrosine dye and a derivative thereof, a triphenylmethane derivative, a quaternary ammonium salt, a quaternary phosphonium salt, a quaternary pyridinium salt, a guanidine salt, and an amidine salt. . These charge control agents may be used alone or in combination of two or more. However, when used in a color developer, a colorless one which does not affect the color tone is preferred. When the charge controlling agent is contained in the one-component developer of the present invention, preferably, based on 100 parts by weight of the binder,
It is used in the range of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight.

Preferred examples of the charge control agent include:
Compounds represented by the following general formulas (I) to (V), and metal complexes or salts of the compounds represented by the general formulas (I), (III) and (IV), represented by the general formula (IV) And boron complexes of the compounds.

[0021]

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(Wherein, A, B, C and D represent an aromatic ring which may have a substituent, and Q represents a direct bond or a divalent linking group). In the formula (I), examples of the aromatic ring represented by A, B, C, or D include a benzene ring, a naphthalene ring,
Examples thereof include an anthracene ring and a phenanthrene ring. Of these, a benzene ring or a naphthalene ring is preferable. When these aromatic rings have a substituent,
Examples of the substituent include a hydrocarbon group, an alkoxy group, an alkylthio group, a dialkylamino group, a nitro group, a cyano group, a hydroxyl group, and a halogen atom. Of these, a halogen atom is preferable. Q represents a direct bond or a divalent linking group, and examples of the divalent linking group include an oxygen atom, a sulfur atom, an alkylimino group, an alkylene group, and an alkylidene group. An alkylene group having 1 to 4 carbon atoms or an alkylidene group having 2 to 4 carbon atoms is preferable. When used as the metal salt of the formula (I),
The metal ion is preferably an alkali metal ion or an alkaline earth metal ion, and more preferably a sodium ion or a potassium ion.

[0023]

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(Wherein, n and m represent an integer of 0 or more;
n + m is 4-10. R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R ³ and R ⁴ each independently represent Represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms which may have a substituent. ) Wherein, R ¹ to R ⁴ is preferably an alkyl group having 1 to 5 carbon atoms which may have a hydrogen atom or a substituent, inter alia R ¹
And R ² is an alkyl group having 3 to 5 carbon atoms which may have a substituent, and R ³ and R ⁴ are more preferably hydrogen atoms. Further, n + m is preferably from 6 to 9, and most preferably 8.

[0025]

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Wherein R ⁵ and R ⁶ are each independently:
It represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. In the formula, R ⁵ and R ⁶ each have 3 to 3 carbon atoms which may have a substituent.
5 alkyl groups are preferred. When a metal complex or a salt of the compound of the formula (III) is used, the metal is preferably a divalent or trivalent metal, and more preferably chromium, aluminum or zinc.

[0027]

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(In the formula, E and F represent an aromatic ring which may have a substituent.) In the formula, the aromatic ring of E and F is preferably a benzene ring or an anthracene ring. More preferred. When these aromatic rings have a substituent, examples of the substituent include a hydrocarbon group, an alkoxy group, an alkylthio group, a dialkylamino group, a nitro group, a cyano group, a hydroxyl group, and a halogen atom. Are preferred. When a metal complex or salt of the compound of the formula (IV) is used, the metal is preferably divalent or trivalent, and more preferably chromium, aluminum or zinc. Further, a boron complex of the compound of the formula (IV) is also preferably used.

[0029]

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Where R⁷~ R^TenEach independently
Hydrogen atom, halogen atom, carbon number which may have a substituent
R 1 represents a hydrocarbon group, a nitro group, or a cyano group;¹¹
And R ¹²Are each independently a hydrogen atom or N-phenyl
Represents a carbamoyl group. M represents a trivalent metal, and X
⁺Is a proton, ammonium ion, or alkali gold
Represents a genus ion. Where R⁷~ R^TenAt least one of which is a nitro group or
Is preferably a chlorine atom. M is chromium or
Iron is preferred and X⁺Is a proton, sodium ion or
Potassium ions are preferred.

The developer of the present invention may further contain paraffin wax having a melting point of 50 ° C. to 100 ° C., higher fatty acid, fatty acid amide, ester wax, ketone wax, rice wax, Fischer-Tropsch wax and the like for the purpose of improving fixability. 0.1 to 30 parts by weight of synthetic and natural low melting point wax may be added to 100 parts of binder resin. The crystal morphology of these low-melting waxes in the developer is not particularly limited. The dispersion diameter is preferably 3.0 μm or less in the major axis. Also, polypropylene wax, polyethylene wax,
0.1 to 30 parts by weight of a modified polypropylene wax, a modified polyethylene wax or the like can be added.

It is also possible to add 0.01 to 20 parts by weight of various silicone oils, modified silicone oils, silicone varnishes and modified silicone varnishes. Further, a lubricant such as a metal soap or a metal stearate can be added internally or externally. Further, fine resin particles made of a styrene resin, an acrylic resin, a benzoguanamine resin, a melamine resin, or the like can be used as a fluidity adjusting agent or a charge adjusting agent. These additives are preferably used in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the binder.

The production of the one-component developer according to the present invention from the above-mentioned components can be carried out according to a conventional method.
When a developer is produced by a pulverization method, first, a binder resin, a colorant, and other components to be added as necessary are uniformly dispersed and mixed by a mixer, and then the mixture is sealed in a closed kneader or a uniaxial or twin screw. Melt kneading with a shaft extruder, etc., after cooling, crushing with a crusher, hammer mill, etc.
Finely crushed with a jet mill, high-speed rotor rotary mill, etc.
Wind classifier (eg, inertial classifier elbow jet,
A classification method using a microplex of a centrifugal classification method, a DS separator, or the like) is employed. Further, it can also be produced by dispersion polymerization such as suspension polymerization and emulsion polymerization. The particle size and particle size distribution of the toner can be used within a known range, but the volume average particle size is preferably 3 to 20 μm,
More preferably, it is in the range of 5 to 9 μm.

When the developer of the present invention is used as a developer for a single color, the storage elastic modulus is preferably 1 × 10 ² (Pa) ≦ G ′ _1% ≦ 1 × 10 in dynamic viscoelasticity measurement at 150 ° C.
⁴ (Pa) and 1 ≦ G ′ _1% / ≦ _G′30% ≦ 10 (G ′ _1% is the storage elastic modulus at 1% strain, and G ′ _30% is the strain 30%
When used as a full-color color developer, it is preferably 120
Storage elastic modulus is 1 × 10 in dynamic viscoelasticity measurement at 100 ° C.
² (Pa) ≦ G ′ _1% ≦ 1 × 10 ⁴ (Pa) and 1 ≦ G ′ _1% /
G ′ _30% ≦ 10 (G ′ _1% is the storage modulus at 1% strain, and G ′ _30% is the storage modulus at 30% strain). The storage elastic modulus can be set by appropriately selecting the binder resin described above, and may be adjusted for the purpose of conforming to the developing device and the fixing method. When the storage elastic modulus is within the above range, it is preferable in terms of fixability, storage stability, and durability when used as a developer for a single color. When used as a full-color color developer, in addition to the above characteristics, OH
P transparency is also good. The dynamic viscoelasticity of the developer was measured by MR-500 manufactured by UBM Co., Ltd. using a parallel plate at a frequency of 1 Hz.

The sphericity (specific surface area / BET specific surface area measured by a Coulter counter) of the developer of the present invention is preferably from 0.3 to 1, more preferably from 0.4 to 1. If the sphericity is significantly lower than the above range, the chargeability is degraded, and the developability and transferability tend to be undesirably reduced.

An example of the image forming method of the present invention will be specifically described using the image forming apparatus shown in FIG. The latent image holder 1 is formed by applying a photosensitive conductive material to an outer peripheral surface of a conductor such as aluminum to form a photosensitive layer. Latent image carrier 1
A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are respectively arranged along the outer peripheral surface of. The charging device 2 includes, for example, a well-known scorotron charger and a roller charger, and uniformly charges the surface of the latent image holding member 1 to a predetermined potential. The exposure device 3 forms an electrostatic latent image on the photosensitive surface of the latent image holding member 1 by exposing the photosensitive surface of the latent image holding member 1 with an LED or laser light.

The developing device 4 includes an agitator 42, a supply roller 43, a developer carrier 44 (hereinafter referred to as a developing roller 44),
The one-component developer T is stored inside the regulating member 45. If necessary, the developing device 4 may be provided with a replenishing device 41 (not shown) for replenishing the developer T. The replenishing device 41 replenishes the developer T from a container such as a bottle or a cartridge. Is what you can do. The supply roller 43 is made of a conductive sponge or the like,
It is in contact with the developing roller 44. The developing roller 44 is disposed between the latent image holding member 1 and the supply roller 43.
The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism. The supply roller 43 carries the stored developer T and supplies it to the developing roller 44. The developing roller 44 carries the developer T supplied by the supply roller 43 and contacts the surface of the latent image holding member 1. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, nickel or the like or a silicon storage roll made of silicon resin,
It is made of a resin roll coated with urethane resin, fluororesin or the like. The surface of the developing roll may be smoothed or roughened as necessary. The regulating member 45 is formed of 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, or a blade obtained by coating a metal blade with a resin. The restricting member 45 includes the developing roller 4
4 and pressed against the developing roller 44 with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / c).
m), and may have a function of imparting charge to the developer T by frictional charging with the developer T as necessary.
The agitator 42 is rotated by a rotation drive mechanism, and agitates the developer T and conveys the developer T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.

The transfer device 5 includes a transfer charger, a transfer roller, a transfer belt and the like which are arranged to face the latent image holding member 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charged potential of the developer T, and transfers an image formed of the developer formed on the latent image holding member 1 to the recording paper P. It is. The cleaning device 6 is composed of a cleaning member such as a urethane blade or a fur brush. The cleaning device scrapes the residual developer adhered to the latent image holding member 1 with the cleaning member, and collects the residual developer.

The fixing device 7 comprises an upper fixing member 71 and a lower fixing member 72, and has a heating device 73 inside the upper or lower fixing member. As the fixing member, a known heat fixing member such as a fixing roll in which a metal tube made of stainless steel or aluminum is coated with a silicone resin, a fixing roll in which a fluororesin is coated with a fluorine resin, a fixing sheet, or the like can be used. Further, a releasing agent such as silicone oil may be supplied to the fixing member in order to improve releasability. 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. Recording paper P
When the developer T transferred above passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the developer T is heated to a molten state, cooled after passing through, and cooled. The developer T is fixed on P.

In the electrophotographic developing device configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the latent image holding member 1 is
To a predetermined potential (for example, -600 V). Subsequently, the exposed surface of the charged latent image carrier 1 is exposed by the exposure device 3 in accordance with the image to be recorded.
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 latent image holding member 1.

In the developing device 4, the developer supplied by the supply roller 43 is thinned by the regulating member 45 and has a predetermined polarity (here, the same polarity as the charging potential of the latent image holding member 1, Is triboelectrically charged,
It is carried on the developing roller 44, transported, and brought into contact with the surface of the latent image holding member 1. An image of the developer T corresponding to the electrostatic latent image is formed on the surface of the latent image holding member 1 from the developing roller 44 by a so-called reversal developing method. Then, this image is transferred to the recording paper P by the transfer device 5. Thereafter, the developer remaining on the photosensitive surface of the latent image holding member 1 without being transferred is removed by the cleaning device 6. The final image is obtained by passing the developer T onto the recording paper P through the fixing device 7 and thermally fixing the developer T.

In the above developing method, the present invention uses the one-component developer described above in various ways. That is, a one-component developer comprising at least a colorant and a binder resin, wherein the developer contains inorganic particles as an external additive, and is free from the total amount of the inorganic particle external additive. It is important to use a one-component developer characterized by having an amount of 5 wt% or less. In particular, it is preferable to use a developer according to the reversal developing method in which the polarity of the electrostatic latent image on the latent image carrier and the polarity of the one-component developer used in the present invention are the same.

[0043]

The present invention will be more specifically described with reference to the following examples.
The present invention will be described with reference to the drawings.
However, the present invention is not limited to the embodiment. [Example 1] Styrene-butyl acrylate copolymer 100
Parts by weight, magnetic powder (“EPT-1000” manufactured by Toda Kogyo Co., Ltd.) 8
0 parts, charge control agent (“Phontron” manufactured by Orient Chemical Co., Ltd.)
S-34 ”) After dispersing and mixing 1 part by weight, use a twin-screw extruder.
And melt-kneaded. After cooling, coarse grinding with a hammer mill
And then pulverize with a supersonic jet mill pulverizer.
Was. The obtained powder was classified with an air classifier, and the particle size was 5 to 30.
A part of μm was obtained. This is referred to as a non-externally added developer. Next
A silica hydrophobic silica having a primary number average particle size of 30 nm;
And silica having a primary number average particle size of 7 nm
The number of particles having a secondary particle diameter of 30 nm is 10 in the entire silica particles.
% Of silica which has not been added to the external developer 100%
Mix with 1.2 parts by weight of Henschel mixer
It was added to obtain a developer having an average particle size of 8.5 μm. Of developer
Physical properties were as follows. Amount of free inorganic particle external additive: 0.9 wt% G ′_1% : 5.9 × 10^ThreePa  G '_30%: 4.7 × 10^ThreePa sphericity: 0.45 Glass transition temperature: 56 ° C

[Comparative Example] Using the non-externally added developer used in the examples
Primary as an external additive prepared in the same manner as in the Examples.
61 particles with a particle diameter of 30 nm based on the total amount of silica particles
A few percent of silica particles are added to 100 parts by weight of
Parts by weight using a Henschel mixer.
One-component developer of 8.5 μm was obtained. The physical properties of the developer are as follows.
It was as follows. Amount of free inorganic particle external additive: 6.3 wt% G ′_1% : 5.9 × 10^ThreePa  G '_30%: 4.7 × 10^ThreePa sphericity: 0.45 Glass transition temperature: 56 ° C

Using the above developer, LB manufactured by Canon Inc.
Table 1 shows the results of actual printing at a printing rate of 5% at P-740. In the case of using the developer of the embodiment, after the actual printing of 10 sheets,
The image density and image quality after actual photographing of 000 sheets were both at a level without any problem. The initial value of the surface roughness of the developer carrier (Ra
¹ ) and the surface roughness (Ra) of the developer carrier after actual copying of 30,000 sheets were 1.75 and 1.15, respectively. On the other hand, when the developer of the comparative example was used, the image density after actual shooting of 10 sheets,
Although the image quality was at a level without any problem, the image density was low after 15,000 actual shots, and image quality defects such as missing characters occurred. The initial value of the surface roughness of the developer carrier (R
a ¹ ) and the surface roughness (Ra) of the developer carrier after actual copying of 15,000 sheets are 1.75 and 1.17, respectively, and the wear rate of the developer carrier is faster than that of the developer of Example. It has been found. (Evaluation items) Image density: Measured by Macbeth RD-914 (Nippon Denshoku Co., Ltd.). Fog: ZΣ-80 (Nippon Denshoku Co., Ltd.) Z, Y, Z
Z value of color system. Image quality: visually inspected

[0046]

[Table 1]

[0047]

[Table 2]

The various physical properties in the present invention are measured by the following methods. 1. Degree of hydrophobicity of external additive of inorganic particles Methanol titration method (1) A 0.20 g (0.20 ± 0.01 g) sample is collected in a beaker, 50 ml of pure water is added, and the liquid surface is stirred with a magnetic stirrer. Inject methanol down. (2) The point at which the sample is no longer observed on the liquid surface is the end point. (3) The degree of hydrophobicity is calculated from the amount of methanol used at the end point by the following equation. 1. Hydrophobicity = Methanol usage X100 / (50 + Methanol usage) Particle Size Distribution of Inorganic Particle External Additives Particle Size Distribution Measurement Method (1) Use Coulter Counter Multisizer Type II (manufactured by Coulter). The aperture diameter is 100 μm. (2) A suitable amount of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to the electrolytic solution Isoton II, and 2 to 20 mg of a measurement sample is further added. (3) The electrolyte in which the sample was suspended
The dispersion treatment is performed for 60 seconds, and the particle size distribution is measured using the Coulter Counter Multisizer II. 3. Sphericity Sphericality of one-component developer (1) The volume average particle diameter D50 is determined by using a Coulter Counter Multisizer II (manufactured by Coulter). (2) The BET specific surface area is obtained by a nitrogen adsorption method using Flow Soap Model 2300 (manufactured by Shimadzu Corporation). (3) Calculate the degree of Wardell's sphericity based on the following equation. 3. Sphericity = Specific surface area / BET specific surface area assuming shape from volume average particle diameter D50 Melting point (1) Using DSC220U (manufactured by Shimadzu Corporation), the melting point is determined from the intersection of the tangent line having the largest slope and the base line among the tangent lines on the low temperature side of the endothermic curve measured at a heating rate of 10 ° C / min.

According to the present invention, the abrasion of the developer carrier is prevented, and the abraded developer carrier has a sufficient charge amount, a sufficient transportability, and a low image density. This makes it possible to provide a one-component developer and a one-component developing method which are high and free from defects such as blurring and voids.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of an image forming apparatus used in an image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 latent image carrier 2 charging device 3 exposure device 4 developing device 5 transfer device 6 cleaning device 7 fixing device 41 replenishing device (not shown) 42 agitator 43 supply roller 44 developer carrier (developing roller) 45 regulating member 71 upper part Fixing member 72 Lower fixing member 73 Heating device T One-component developer P Recording paper

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukihiro Sato 1-Fukudacho, Joetsu-shi, Niigata F-term in Naoetsu Works, Mitsubishi Chemical Corporation (reference) 2H005 AA02 AA08 AA15 AA21 CA21 CB13 EA05 EA07 EA10 FA06 2H077 AC04 AD06 AD13 AD17 EA13 FA01 FA22 FA25 FA26 GA17

Claims (10)

[Claims] 1. A one-component developer comprising at least a colorant and a binder resin, wherein the developer contains inorganic particles as an external additive, and free inorganic particles are added to the total amount of the inorganic particle external additive. A one-component developer, wherein the amount of the developer is 5 wt% or less. 2. The method according to claim 1, wherein the content of the inorganic particle external additive having a primary particle size of 30 nm or more is 50% by number or less based on the total amount of the inorganic particle external additive. Component developer. 3. The method according to claim 1, wherein the amount of the inorganic particle external additive is 0.3 to 5% by weight based on the developer.
A one-component developer according to any one of the above. 4. The one-component developer according to claim 1, wherein the one-component developer contains a magnetic powder. 5. The one-component developer according to claim 1, wherein the sphericity of the one-component developer is 0.3 to 1. 6. In a dynamic viscoelasticity measurement at 150 ° C.,
The storage elastic modulus of the one-component developer is 1 × 10 ² Pa ≦ G ′ _1% ≦ 1
× 10 ⁴ Pa and 1 ≦ G ′ _1% / G ′ _30% ≦ 10 (however, G ′
_1% represents a storage modulus at 1% strain, G _'30% one component developer according to any one of claims 1 to 5, characterized in that a showing a storage modulus at strain of 30%) . 7. In a dynamic viscoelasticity measurement at 120 ° C.,
The storage elastic modulus of the one-component developer is 1 × 10 ² Pa ≦ G ′ _1% ≦ 1
× 10 ⁴ Pa and 1 ≦ G ′ _1% / G ′ _30% ≦ 10 (however,
G ' _1% indicates the storage modulus at 1% strain, G' _30% indicates the storage modulus at _30% strain), and the developer is any one of magenta, cyan and yellow colorants. The one-component developer according to claim 1, further comprising: 8. The one-component developer has an initial value (Ra ¹ ) of the surface roughness of the developer carrying member (Ra).
The developer is used in a range of 70% or less, and the developer is regulated to a thin layer by a regulating member that comes into contact with the developer carrier with the developer interposed therebetween. The one-component developer according to claim 1, wherein the one-component developer is used in a one-component developing method for developing a latent image. 9. A one-component developer is formed into a one-component developer layer by regulating the thickness of the one-component developer with a regulating member which comes into contact with the developer carrier with the developer layer interposed therebetween. In the one-component developing method of supplying and developing an electrostatic latent image, as the developer, a one-component developer comprising at least a colorant and a binder resin, the developer containing inorganic particles as an external additive, And a developing method using a one-component developer, wherein the amount of the free inorganic particle external additive is 5 wt% or less based on the total amount of the inorganic particle external additive. 10. The developing method according to claim 9, wherein the developing is performed by a reversal developing method in which the polarity of the electrostatic latent image on the latent image holding member and the polarity of the one-component developer are the same.