JP2002156786A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method, in which the electrifying property and the carrying ability of toner in development are stable and the deterioration of image quality is reduced, even in the case of repeatedly forming an image over a long term. SOLUTION: In an image forming system, where nonmagnetic toner, consisting of at least resin, a releasing agent and a colorant, is used to form a thin layer on the surface of a toner carrier, and carried to a developing area so as to develop the image the surface roughness of the toner carrier is 1 to 10 μm and the toner obtained by salting out/fusing resin particles, constituted by including the releasing agent in binding resin and the colorant, is used as the toner in this image forming method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic one-component image forming method used for a copying machine, a printer, and the like.

[0002]

2. Description of the Related Art A non-magnetic one-component developing system is disclosed in, for example, JP-A-63-21946 and 63-27137.
Japanese Patent No. 4 and Japanese Patent No. 2774534 are known. This method includes a toner conveying member (also referred to as a toner carrier), a toner layer regulating member and a toner replenishing auxiliary member, and the toner replenishing auxiliary member and the toner conveying member, and the toner layer regulating member and the toner conveying member contact each other. In this method, a non-magnetic toner having a reduced thickness is supplied to the surface of the electrostatic latent image forming body to develop the latent image by a developing device having the above configuration. In this method, the non-magnetic toner is charged by frictional charging between the non-magnetic toner and the toner conveying member or the toner layer regulating member.

However, when this method is used, fogging or the like occurs when used for a long time as a major problem, and a solution to this problem is required. One of the main reasons why this phenomenon occurs is that the toner is apt to fuse to the members for transporting the toner and the members for regulating the toner layer, and as a result, the triboelectric charging property is reduced. It is considered that this is because the charge amount of the toner decreases.

Further, in the case of the conventional pulverized toner, fine powder of the toner is generated at the time of pulverization, and it is difficult to classify and remove it, so that it remains in the final toner. When a toner containing such fine powder is used, since the fine powder itself has a strong adhesive property, the fine powder itself does not move while adhering to the surface of the toner conveying member, and is repeatedly subjected to stress by the toner layer regulating member, and as a result, the toner It fuses and lowers the ability of the toner conveying member to provide charge. As a result, fog or the like is likely to occur due to a decrease in the charge amount of the non-magnetic toner or an increase in the charge amount distribution (such as an increase in the amount of weakly chargeable toner). In addition, if the toner constituents are fused to the surface of the toner conveying member, defective conveyance of the toner occurs, causing a problem such as a reduction in image density.

As a measure for solving the problem of the fine powder toner, JP-A-60-31147 and JP-A-60-10765 are known.
JP-A-6-117255 and JP-A-60-117255 propose the use of a suspension polymerization toner which is spherical and has a small particle size distribution. However, since the suspension polymerization toner is a true sphere, it is difficult to regulate the toner by the toner layer regulating member, and there is a strong tendency that the amount of the toner is excessively conveyed. In addition, there is also a problem that cleaning is difficult in the case of a true spherical shape because of its strong adhesion to the photoreceptor.

[0006] In order to solve the above-mentioned problem, there has been proposed a method in which the shape of the toner is changed from a true spherical shape to a shape having irregularities on the toner surface. For example, JP-A-7-
Japanese Patent No. 36207 proposes an image forming method in which the level of toner deformation is defined by a shape factor to solve these problems.

However, the toner deforming means disclosed therein is a conventional method in which resin particles are adhered to the surface of a suspension-polymerized toner to deform the toner, or the suspension-polymerized toner is swollen by immersion in a solvent. Then, it is a method of drying under reduced pressure and deforming. In the deforming of the surface of the suspension polymerization toner due to the adhesion of resin particles, the resin particles adhered to the surface are separated from the toner surface due to frictional stress with the toner conveying member and the toner layer regulating member, or the charged charges are concentrated on the resin particles on the surface. In addition, the charge amount distribution tends to be broad, and the resolution of characters is degraded. Further, a toner whose surface is deformed by swelling the suspension polymerization toner by immersion in a solvent tends to have a large difference in toner characteristics due to a difference in production lot, and therefore has a problem that image quality is not stable. As a result, although a non-magnetic one-component developing method is a simple and useful technique, it is not recognized as a technique capable of forming a stable image over a long period of time.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed by making the surface roughness of a toner carrier specific, and making the toner have a specific surface property and shape. Another object of the present invention is to provide an image forming method in which even when an image is repeatedly formed over a long period of time, the chargeability and transportability of the toner during development are stable, and the image quality is hardly deteriorated.

[0009]

Means for Solving the Problems The present inventors have intensively studied and analyzed the image deterioration phenomenon in non-magnetic one-component development, and as a result, have completed the present invention.

That is, the object of the present invention is achieved by adopting one of the following constitutions. [1] In an image forming method in which a non-magnetic toner comprising at least a resin, a release agent and a colorant is used, a thin layer is formed on the surface of the toner carrier, and is conveyed to a development area for development. It is characterized in that the toner has a roughness of 1 to 10 μm and is obtained by salting out / fusing resin particles containing a release agent in a binder resin and a colorant. Image forming method.

[2] In an image forming method in which a thin layer is formed on the surface of a toner carrier using a non-magnetic toner comprising at least a resin, a release agent and a colorant, the toner is transported to a development area and developed. The surface roughness of the body is 1 to 10 μm, and the shape factor of the toner is 0.930 to 0.98
0, and the coefficient of variation of the shape factor is less than 10%.

Although the reason why the object of the present invention is achieved by each of the above-mentioned structures is not fully understood, it is considered as follows.

When the release agent is exposed on the surface of the toner or when the release agent is free in the toner, filming of the release agent on the surface of the toner carrier is likely to occur. Further, when the shape of the toner particles is not uniform, it is susceptible to mechanical stress due to agitation or the like inside the developing device,
By generating parts where excessive stress is applied,
The toner composition adheres to the surface of a triboelectric charging member such as a toner carrier. As a result, toner transportability is reduced,
It is estimated that the chargeability changes.

The difference in the manner in which the stress is applied also depends on the surface roughness of the toner carrier and the particle size of the toner particles. A smaller particle size has a higher adhesive force than its mass. However, when subjected to stress, the result is easy to cause contamination. If the toner particle size is large, such contamination is unlikely to occur, but if the particle size is increased to such a range, there arises a problem that the image quality such as resolution deteriorates.

By adjusting the surface roughness of the toner carrier to 1 to 10 μm, the toner transportability can be made appropriate. If the surface roughness exceeds 10 μm, the toner transportability becomes excessive. As a result, poor charging of the toner occurs. On the other hand, if the surface roughness is less than 1 μm, the transportability of the toner is too low, the developability is insufficient, and the stress on the toner is increased to cause filming on the surface of the toner carrier.

The surface roughness of the toner carrier of the present invention is 1 to 10 μm, preferably 2 to 7 μm as a center line average roughness (hereinafter referred to as Ra). If the surface roughness is less than 1 μm, the toner transportability is reduced, and a sufficient image density may not be obtained. If the surface roughness is more than 10 μm, the toner transport amount becomes too large and the chargeability of the toner becomes insufficient.

Incidentally, Ra is the Japanese Industrial Standard (JIS) B0.
601-1982.

The surface roughness of the toner carrier can be adjusted by previously roughening the surface of the mold forming the developer carrying member to a desired roughness.

According to the present invention, since the toner is obtained by salting out / fusing resin particles containing a release agent in a binder resin and a colorant, filming on a toner carrier is achieved. Since the easy release agent is not exposed on the toner surface and there are no large release agent particles free in the toner, it is considered that filming hardly occurs and the transportability is stabilized. In addition, it is considered that fogging hardly occurs because the toner surface is appropriately uniform, and since there is no corner unlike a pulverized toner, the chargeability is also uniform.

On the other hand, the shape factor of the toner is set to 0.930.
By setting the coefficient of variation of the shape factor to less than 10%, the shape of the toner can be made somewhat irregular, and the transportability of the toner to the surface of the toner carrier can be improved. it can.

When the shape factor is 0.980 or more, the degree of sphericity of the toner itself is high, so that a sufficient shear stress cannot be applied when conveying the toner, and the conveyance is not stable. Further, in the case of a shape factor of 0.930 or less, the degree of irregular shape is large, so that it is easy to receive stress during transportation, the toner corner is easily worn, and the problem of fusing to the surface of the toner carrier is easily caused. .

Further, it is preferable that the distribution of the shape coefficient is sharp, and a toner having a uniform shape can be obtained by setting the variation coefficient of the shape coefficient to less than 10%. Since the difference in performance such as the difference in chargeability can be reduced, the developability can be stabilized for a long time.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

<Non-Magnetic Toner> As described above, the toner of the present invention is a toner containing at least a resin, a colorant, and a release agent, wherein resin particles containing a release agent in a binder resin; It is composed of associative particles obtained by salting out / fusing colorant particles. Alternatively, the toner is any one of toner whose shape factor is 0.930 to 0.980 and whose coefficient of variation of the shape factor is less than 10%.

<Release Agent> The release agent constituting the toner of the present invention is not particularly limited, but a crystalline ester compound represented by the following general formula (1)
It is referred to as “specific ester compound”. ) Is preferable.

General formula (1) R _1- (OCO-R ₂ ) _n (wherein R ₁ and R ₂ are each a hydrocarbon group having 1 to 40 carbon atoms which may have a substituent. And n is 1
-4. In the general formula (1) representing a specific ester compound,
₁ and R ₂ each represent a hydrocarbon group which may have a substituent.

The hydrocarbon group R ₁ has 1 to 40 carbon atoms, preferably 1 to 20, more preferably 2 to 5 carbon atoms.

The hydrocarbon group R ₂ has 1 to 40 carbon atoms, preferably 16 to 30, more preferably 18 to 26.
It is said.

In the general formula (1), n is 1 to 4
And preferably 2 to 4, more preferably 3
To 4, particularly preferably 4.

The specific ester compound can be suitably synthesized by a dehydration condensation reaction between an alcohol and a carboxylic acid.

The most preferred specific ester compound is pentaerythritol tetrabehenate.

Specific examples of the specific ester compound include:
Compounds represented by the following formulas 1) to 22) can be exemplified.

[0033]

Embedded image

[0034]

Embedded image

The content of the release agent in the toner of the present invention is usually 1 to 30% by mass, preferably 2 to 30% by mass.
The content is 20% by mass, more preferably 3 to 15% by mass.

<Resin Particles Having a Release Agent Encapsulated in a Binder Resin> In the present invention, “resin particles having a release agent included in a binder resin” is a monomer for obtaining a binder resin. A release agent is dissolved therein, the resulting monomer solution is dispersed in an aqueous medium, and this system is subjected to a polymerization treatment to obtain latex particles.

The weight average particle size of the resin particles is 50 to 2
It is preferably 000 nm. Examples of a polymerization method for obtaining resin particles containing a release agent in a binder resin include a granulation polymerization method such as an emulsion polymerization method, a suspension polymerization method, and a seed polymerization method.

As a preferred polymerization method for obtaining resin particles containing a release agent, a release agent is contained in a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. A method of preparing a dispersion by dispersing the dissolved monomer solution in oil droplets using mechanical energy, adding a water-soluble polymerization initiator to the obtained dispersion, and subjecting the resulting dispersion to radical polymerization (hereinafter referred to as a radical polymerization). , "Mini-emulsion method").

Instead of adding the water-soluble polymerization initiator, or together with the addition of the water-soluble polymerization initiator, an oil-soluble polymerization initiator may be added to the monomer solution. .

Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirrer “CLEARMIX” (CLEARMIX) equipped with a high-speed rotating rotor is used. M-Technic Co., Ltd.), an ultrasonic disperser, a mechanical homogenizer, a Menton-Gaulin and a pressure homogenizer. Further, the dispersion particle diameter is 1
0 to 1000 nm, preferably 30 to 300 nm
It is said.

Hereinafter, the constituent materials and the preparation method (polymerization method) of the resin particles will be described. [Monomer] As the polymerizable monomer used to obtain the resin particles, a radical polymerizable monomer is an essential component, and a crosslinking agent can be used as necessary. Further, at least one radical polymerizable monomer having an acidic group or the following radical polymerizable monomer having a basic group is used.
It is preferable to contain them.

(1) Radical Polymerizable Monomer The radical polymerizable monomer is not particularly limited, and a conventionally known radical polymerizable monomer can be used. In addition, one kind or a combination of two or more kinds can be used so as to satisfy required characteristics.

Specifically, aromatic vinyl monomers, (meth) acrylate monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers Monomers, halogenated olefin monomers and the like can be used.

As the aromatic vinyl monomer, for example,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n- Styrene-based monomers such as octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, 2,4-dimethylstyrene, and 3,4-dichlorostyrene, and derivatives thereof. .

(Meth) acrylate monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate Butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl benzoate and the like.

Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

Examples of the monoolefin-based monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

Examples of the diolefin-based monomer include butadiene, isoprene, chloroprene and the like.

Examples of the halogenated olefin monomer include:
Vinyl chloride, vinylidene chloride, vinyl bromide and the like.

(2) Crosslinking Agent A radical polymerizable crosslinking agent may be added to the monomer solution in order to improve the properties of the toner. Examples of the radical polymerizable crosslinking agent include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Radical polymerizable monomer having an acidic group or a basic group Examples of the radical polymerizable monomer having an acidic group or the radical polymerizable monomer having a basic group include a carboxyl group. Compound, sulfonic acid group-containing compound, primary amine, secondary amine, tertiary amine, quaternary amine
An amine compound such as a quaternary ammonium salt can be used.

Examples of the radical polymerizable monomer having an acidic group include carboxylic acid group-containing monomers such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monobutyl maleate, And monooctyl maleate.

Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfosuccinic acid, octyl allyl sulfosuccinate and the like.

These may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium.

Examples of the radical polymerizable monomer having a basic group include amine compounds, such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the quaternary of the above four compounds. Ammonium salt, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, acrylamide, N-butylacrylamide, N, N-dibutylacrylamide,
Piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N-octadecylacrylamide, vinylpyridine, vinylpyrrolidone, vinyl N-methylpyridinium chloride, vinyl N-ethylpyridinium chloride, N, N-diallylmethylammonium chloride, N, N- Diallylethylammonium chloride and the like can be mentioned.

As the radical polymerizable monomer used in the present invention, a radical polymerizable monomer having an acidic group or a radical polymerizable monomer having a basic group may be used in an amount of 0.1 to 15% of the whole monomer. The radical polymerizable cross-linking agent is preferably used in an amount of 0.1 to 10% by mass with respect to the total radical polymerizable monomer, although it depends on its properties.

[Chain Transfer Agent] For the purpose of adjusting the molecular weight of the resin particles, it is possible to use a commonly used chain transfer agent.

The chain transfer agent is not particularly restricted but includes, for example, mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, carbon tetrabromide and styrene dimer.

[Polymerization Initiator] The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble.
For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4'-azobis-4-cyanovaleric acid and its salts, 2,2'-azobis (2-amidinopropane) salts, etc.), peroxides And the like.

Further, the above radical polymerization initiator can be combined with a reducing agent, if necessary, to form a redox initiator. By using a redox-based initiator, the polymerization activity is increased, the polymerization temperature can be reduced, and a further reduction in the polymerization time can be expected.

As the polymerization temperature, any temperature may be selected as long as it is equal to or higher than the minimum radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, by using a polymerization initiator started at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (such as ascorbic acid), polymerization can be performed at room temperature or higher.

[Surfactant] In order to carry out polymerization using the above-mentioned radical polymerizable monomer, it is necessary to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used at this time is not particularly limited, but the following ionic surfactants can be mentioned as preferred examples.

Examples of the ionic surfactant include sulfonates (sodium dodecylbenzene sulfonate, sodium arylalkyl polyether sulfonate, 3,3-
Sodium disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline,
2,2,5,5-tetramethyl-triphenylmethane-
4,4-diazo-bis-β-naphthol-6-sulfonate, etc.), sulfates (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, laurin) Sodium, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.).

Further, a nonionic surfactant can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, an ester of polyethylene glycol and higher fatty acid, an alkylphenol polyethylene oxide, an ester of higher fatty acid and polyethylene glycol, an ester of higher fatty acid and polypropylene oxide, a sorbitan ester And the like.

<Colorant> Examples of the colorant constituting the toner of the present invention include inorganic pigments, organic pigments and dyes.

Conventionally known inorganic pigments can be used. Specific inorganic pigments are exemplified below.

Examples of black pigments include furnace black, channel black, acetylene black,
Carbon black such as thermal black and lamp black is also used.

These inorganic pigments can be used alone or in combination of two or more as desired. The amount of the pigment to be added is 2 to 20% by mass, preferably 3 to 15% by mass, based on the polymer.

Conventionally known organic pigments and dyes can also be used. Specific examples of organic pigments and dyes are shown below.

The pigments for magenta or red include:
C. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16,
C. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57:
1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139,
C. I. Pigment red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I.
I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 and the like.

Examples of pigments for orange or yellow include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I.
I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I.
Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment Yellow 185, C.I.
I. Pigment yellow 155, C.I. I. Pigment Yellow 156 and the like.

The pigments for green or cyan include:
C. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3,
C. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111,
122, C.I. I. Solvent Yellow 19, 44
77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93
95 and the like, and mixtures thereof can also be used.

These organic pigments and dyes can be used alone or in combination of two or more as desired. The amount of the pigment to be added is 2 to 20% by mass, preferably 3 to 15% by mass, based on the polymer.

The colorant can be used after surface modification. As the surface modifier, a conventionally known one can be used, and specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like can be preferably used.

<Manufacturing Process of Toner> As an example of a method for manufacturing the toner of the present invention, (1) a dissolving process of dissolving a release agent in a monomer to prepare a monomer solution; Dispersion step of dispersing monomer solution in aqueous medium (3) A dispersion (latex) of resin particles containing a release agent is prepared by polymerizing the aqueous dispersion of the obtained monomer solution. Polymerization step (4) Salting out / fusing step of salting out / fusing the obtained resin particles and the colorant particles in an aqueous medium to obtain associated particles (toner particles). A filtration / washing step of filtering out from the aqueous medium and washing and removing a surfactant and the like from the associated particles; (6) a drying step of the washed associated particles; and (7) an external additive to the dried associated particles. A step of adding an external additive to be added may be included.

[Dissolution Step] The method for dissolving the release agent in the monomer is not particularly limited.

With respect to the amount of the release agent dissolved in the monomer, the content of the release agent in the finally obtained toner is 1 to 3
The amount is 0% by mass, preferably 2 to 20% by mass, more preferably 3 to 15% by mass.

Incidentally, an oil-soluble polymerization initiator and other oil-soluble components can be added to the monomer solution.

[Dispersion Step] The method of dispersing the monomer solution in the aqueous medium is not particularly limited, but is preferably a method of dispersing by means of mechanical energy. It is preferable to disperse the monomer solution in oil droplets using mechanical energy in an aqueous medium in which a surfactant is dissolved (an essential mode in the miniemulsion method).

Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, “CLEARMIX”, an ultrasonic disperser, a mechanical homogenizer, a Menton-Gaulin and a pressure Examples include a formula homogenizer. Further, the dispersed particle diameter is set to 10 to 1000 nm, preferably 30 to 300 nm.

[Polymerization Step] In the polymerization step, a conventionally known polymerization method (a granulation polymerization method such as an emulsion polymerization method, a suspension polymerization method, or a seed polymerization method) can be basically used.

An example of a preferred polymerization method is a mini-emulsion method, that is, a method in which a monomer solution is converted into an oil-based medium using mechanical energy in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. A method in which a water-soluble polymerization initiator is added to a dispersion obtained by drop dispersion to carry out radical polymerization can be exemplified.

[Salt-out / fusion step] In the salt-out / fusion step, a dispersion of colorant particles is added to a dispersion of resin particles obtained by the above-mentioned polymerization step, and the resin particles and the colored The agent particles are salted out / fused in an aqueous medium.

In the salting-out / fusion step, internal additive particles such as a charge control agent can be fused together with the resin particles and the colorant particles.

The “aqueous medium” in the salting-out / fusion step refers to a medium whose main component (50% by mass or more) is water. Here, examples of the component other than water include an organic solvent soluble in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran.
Of these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, are particularly preferable.

The colorant particles used in the salting out / fusion step can be prepared by dispersing the colorant in an aqueous medium. The colorant dispersion treatment is performed in a state where the surfactant concentration is equal to or higher than the critical micelle concentration (CMC) in water.

The disperser used for dispersing the colorant is not particularly limited, but is preferably "Clearmix", an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as Menton Gorin or a pressure homogenizer, or a sand grinder. And a media type disperser such as a Getzman mill or a diamond fine mill. Examples of the surfactant used include the same surfactants as described above.

The colorant (particle) may be surface-modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the dispersion, and the system is reacted by raising the temperature of the system. After completion of the reaction, the colorant is separated by filtration, washed and filtered repeatedly with the same solvent, and then dried to obtain a colorant (pigment) treated with a surface modifier.
Is obtained.

In the salting-out / fusing method, a salting-out agent comprising an alkali metal salt and / or an alkaline earth metal salt is coagulated in water in which resin particles and colorant particles are present. This is a step in which salting out is advanced by simultaneously heating the resin particles to a temperature equal to or higher than the glass transition point of the resin particles, and simultaneously performing fusion. In this step, an organic solvent that is infinitely soluble in water may be added.

Here, the alkali metal salt and alkaline earth metal salt as salting-out agents include lithium, potassium, sodium and the like as alkali metals, and magnesium, calcium, strontium, barium and the like as alkaline earth metals. And preferably potassium, sodium, magnesium, calcium and barium. Examples of the salt include chloride, bromide, iodine, carbonate, sulfate and the like.

Further, the organic solvent infinitely soluble in water includes methanol, ethanol, 1-propanol,
2-propanol, ethylene glycol, glycerin,
Acetone and the like can be mentioned, and alcohols of methanol, ethanol, 1-propanol and 2-propanol having 3 or less carbon atoms are preferable, and 2-propanol is particularly preferable.

In the salting-out / fusion step, it is preferable to minimize the time for which the salting-out agent is left after the addition (the time until the start of heating). That is, it is preferable that the heating of the dispersion of the resin particles and the colorant particles is started as soon as possible after the addition of the salting-out agent, so that the temperature is equal to or higher than the glass transition temperature of the resin particles.

Although the reason for this is not clear, the aggregation state of the particles fluctuates depending on the standing time after salting out, the particle size distribution becomes unstable, and the surface property of the fused toner fluctuates. Problems occur.

Time until heating starts (leaving time)
Is usually within 30 minutes, preferably within 10 minutes.

The temperature at which the salting-out agent is added is not particularly limited, but is preferably equal to or lower than the glass transition temperature of the resin particles.

In the salting-out / fusion step, it is necessary to rapidly raise the temperature by heating, and the rate of temperature rise is preferably 1 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing generation of coarse particles due to rapid salting out / fusion.

Further, after the dispersion of the resin particles and the colorant particles reaches a temperature equal to or higher than the glass transition temperature, the temperature of the dispersion is maintained for a certain period of time, so that the salting-out / fusion can be continued. It is important. Thereby, the growth of the toner particles (aggregation of the resin particles and the colorant particles) and the fusion (the disappearance of the interface between the particles) can be effectively advanced, and the durability of the finally obtained toner is improved. can do.

Also, after stopping the growth of the associated particles,
The fusion by heating may be continued.

[Filtration / Washing Step] In this filtration / washing step, a process of filtering the toner particles from the dispersion liquid of the toner particles obtained in the above step and a step of filtering the toner particles (a cake-like aggregate) are performed. ) Is subjected to a washing treatment for removing extraneous matter such as a surfactant and a salting-out agent from the material.

Here, the filtration method is not particularly limited, such as a centrifugal separation method, a reduced pressure filtration method using a Nutsche or the like, and a filtration method using a filter press or the like.

[Drying Step] This step is a step of drying the washed toner particles.

[0104] Examples of the dryer used in this step include a spray dryer, a vacuum freeze dryer, and a reduced-pressure dryer. A stationary shelf dryer, a moving shelf dryer, a fluidized bed dryer, and a rotary dryer It is preferable to use a dryer, a stirring dryer, or the like.

The water content of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less.

Incidentally, the dried toner particles are
In the case where the aggregates are aggregated by a weak attraction between particles, the aggregates may be crushed. Here, as the crushing device,
A mechanical pulverizer such as a jet mill, a Henschel mixer, a coffee mill, and a food processor can be used.

[Step of Adding External Additive] This step is a step of adding an external additive to the dried toner particles.

Examples of the device used for adding the external additive include a turbulent mixer, a Hensiel mixer,
Various known mixing devices such as a Nauta mixer and a V-type mixer can be used.

Here, the particle size of the toner is preferably 3 to 9 μm in number average particle size because of good image quality. The number average particle size of the toner can be measured using a Coulter Counter TA-II, a Coulter Multisizer, a SLAD1100 (a laser diffraction particle size measuring device manufactured by Shimadzu Corporation), or the like. In the Coulter Counter TA-II and the Coulter Multisizer, those measured using an aperture having an aperture diameter of 100 μm and a particle size distribution in the range of 2.0 to 40 μm are shown.

In the toner of the present invention, a material capable of imparting various functions as a toner material may be added in addition to the colorant and the release agent. Specific examples include a charge control agent. These components can be added simultaneously with the resin particles and the colorant particles in the above-mentioned salting-out / fusion step, and can be added by various methods such as a method of including in the toner and a method of adding to the resin particles themselves.

The charge control agents are also various known ones,
What can be dispersed in water can also be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof.

<External Additives> As described above, so-called external additives can be added to the toner of the present invention for the purpose of improving fluidity, chargeability, and cleaning properties. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles, and lubricants can be used.

As the inorganic fine particles, conventionally known inorganic fine particles can be used. Specifically, silica, titanium, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic. Specifically, as silica fine particles, for example, commercial products R-805, R-976, R-974, and R-97 manufactured by Nippon Aerosil Co., Ltd.
2, R-812, R-809, HVK- manufactured by Hoechst
2150, H-200, commercial product TS- manufactured by Cabot Corporation
720, TS-530, TS-610, H-5, MS-
5 and the like.

Examples of titanium fine particles include commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercially available products MT-100S, MT-100B and MT-5 manufactured by Teica.
00BS, MT-600, MT-600SS, JA-
1. Commercial products TA-300SI, TA-
500, TAF-130, TAF-510, TAF-5
10T, commercial products IT-S, IT-OA manufactured by Idemitsu Kosan Co., Ltd.
IT-OB, IT-OC, TTO manufactured by Ishihara Sangyo Co., Ltd.
-55 and the like.

Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd.

As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. As this, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

Examples of the lubricant include salts of zinc, aluminum, copper, magnesium, calcium and the like of stearic acid, salts of zinc, manganese, iron, copper and magnesium of oleic acid, and zinc, copper, magnesium and calcium of palmitic acid. Metal salts of higher fatty acids such as salts of linoleic acid such as zinc and calcium, and salts of ricinoleic acid such as zinc and calcium.

The addition amount of these external additives is preferably 0.1 to 5% by mass based on the toner. The toner of the present invention is an associative toner obtained by salting out / fusing resin particles containing a release agent and colorant particles in an aqueous medium. As described above, by salting out / fusing the resin particles containing the release agent, a toner in which the release agent is finely dispersed can be obtained.

The toner of the present invention has a shape having irregularities on its surface from the time of its production, and further has an association type obtained by fusing resin particles and colorant particles in an aqueous medium. Since the toner is a toner, the difference in shape and surface property between toner particles is extremely small, and as a result, the surface property tends to be uniform. For this reason, there is little difference in fixability between toners, and good fixability can be maintained.

<Shape Factor of Toner> As the shape of the toner according to the second aspect of the present invention, the average value (average circularity) of the shape factor (circularity) represented by the following equation is 0. .930 to 0.980. More preferably 0.9
40 to 0.975.

Shape factor = (circumferential length of circle obtained from equivalent circle diameter) / (perimeter of particle projected image) The variation coefficient of the shape factor is represented by the following, and the requirement in the second invention is 10 %.

Coefficient of variation (%) of shape coefficient = (standard deviation of circularity / average circularity) × 100 The method of measuring the shape coefficient is not limited.
For example, the average circularity is calculated by taking a photograph in which the toner particles are magnified 500 times with an electron microscope, measuring the circularity of 500 or more toners using an image analyzer, and calculating an arithmetic average value thereof. can do. In addition, as a simple measurement method, it can be measured by FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.).

In order to control the shape factor and the distribution of the shape factor, it is a preferable method to control the temperature or time for fusing the associated particles in the salting-out / fusing step in the above-described toner manufacturing process. .

<Image Forming Method Using Non-Magnetic Toner of the Present Invention> A developing device used in the image forming method of the present invention will be described. The developing device used in the present invention includes a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member,
In addition, the toner replenishing auxiliary member and the toner conveying member are in contact with each other, and the toner layer regulating member and the toner conveying member are in contact with each other. In this method, the non-magnetic toner thinned by using the apparatus is supplied to the surface of the electrostatic latent image forming body to develop the latent image.

The toner conveying member supplies a non-magnetic one-component toner to an electrostatic latent image forming member (in many cases, an electrophotographic photosensitive member). This is preferably a member having elasticity in order to secure a sufficient developing area by the elasticity of the member in contact with the electrostatic latent image forming body.

In the present invention, an elastic roller provided with a high-resistance thin layer on the surface is used as the toner conveying member.

As a material constituting the base of the elastic roller, for example, a rubber material such as ethylene-propylene-diene-methylene copolymer rubber (EPDM), silicone rubber, urethane rubber, etc. is used. Disperse carbon black such as acetylene black, furnace black, etc. to make the volume resistivity 10 ⁶ Ω
-What is smaller than cm is preferable.

On the other hand, as a material constituting the high-resistance thin layer provided on the surface of the substrate, a resin material such as nylon or urethane having a volume resistivity of 10 ¹⁰ Ω · cm or more is used. It is preferable to set the thickness of the high resistance layer in the range of 50 to 100 μm from the viewpoint of developing performance.

The toner layer regulating member has a function of uniformly applying toner to the toner conveying member and imparting triboelectric charging. This is urethane rubber,
An elastic body such as a metal plate is used, and this is brought into contact with the toner conveying member to form a thin layer of toner on the toner conveying member.
A thinned layer means that a maximum of 10
It is a layer formed by overlapping layers, preferably 5 layers or less.
It should be noted that the toner layer regulating member is set at 0.
The contact is preferably performed at a pressure of 1 N / cm to 5.0 N / cm. More preferably, 0.2 to 4.0 N /
cm. When the pressure is less than 0.1 N / cm, the toner conveyance becomes non-uniform, the conveyance unevenness is apt to occur, and the problem that white stripes appear on the image is apt to occur. Further, the toner conveying member preferably has a diameter of 10 to 50 mm.

The toner replenishment assisting member is a unit for stably supplying toner to the toner conveying member. As this, a water wheel-shaped roller or a sponge-shaped roller with stirring blades can be used.
It is preferable that the diameter of the toner conveying member is in the range of 0.2 to 1.5 times the diameter of the toner conveying member. If the diameter is too small, the supply of the toner becomes insufficient. If the diameter is too large, the supply becomes excessive, so that the toner supply is not stabilized in any case, and streak-like image defects are likely to occur.

Hereinafter, the developing device of the image forming method of the present invention will be specifically described. FIG. 1 is a schematic sectional view of a developing device of the image forming method of the present invention.

In FIG. 1, the non-magnetic one-component toner 16 contained in the toner tank 17 is forcibly conveyed and supplied onto a sponge roller 14 also serving as a toner supply assisting member by a stirring blade 15 serving as a toner supply assisting member. You. The toner incorporated on the sponge roller in this way is conveyed onto a rubber roller 12 as a toner conveying member by the rotation of the roller 14 in the direction of the arrow, and the surface of the sponge roller is electrostatically and physically rubbed by friction with the roller 12. Adsorbed. On the other hand, the toner adhering to the rubber roller 12 is rotated by the roller 12 in the direction of the arrow and a steel elastic blade 13 as a toner layer thickness regulating member.
, And is triboelectrically charged. Next, the latent image is developed by contacting or approaching the thin toner layer on the rubber roller 12 with the surface of the electrophotographic photosensitive drum 11 as an electrostatic latent image carrier.

The developing device used in the present invention is shown in FIG.
Of course, the present invention is not limited to this.

[0134]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the following, “parts” means “parts by mass”.

[Preparation Example of Latex] 5000 m equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device.
6. Anionic surfactant (sodium dodecylbenzenesulfonate: SDS) is placed in a 1 l separable flask.
A surfactant solution (aqueous medium) prepared by dissolving 08 g in ion-exchanged water (2760 g) was charged under a nitrogen stream at 230 rpm.
The internal temperature was raised to 80 ° C. while stirring at a stirring speed of.

On the other hand, 72.0 g of a compound represented by the above formula (19) (hereinafter referred to as “exemplary compound (19)”) was obtained.
120.0 g of styrene, n-butyl acrylate
0 g and 11.0 g of methacrylic acid were added to a monomer mixture, and the mixture was heated to 80 ° C. and dissolved to prepare a monomer solution.

The monomer solution (8) was introduced into the surfactant solution (82 ° C.) by a mechanical disperser having a circulation path.
0 ° C.) to prepare a dispersion liquid of emulsified particles (oil droplets) having a uniform dispersed particle diameter.

Next, 0.84 g of a polymerization initiator (potassium persulfate: KPS) was added to this dispersion liquid in 200 parts of ion-exchanged water.
g of an initiator solution, and the system is heated and stirred at 80 ° C. for 3 hours to polymerize (first polymerization).
Stage polymerization) to prepare a latex.

Next, to this latex was added an initiator solution obtained by dissolving 7.73 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water, and after 15 minutes, 384.0 g of styrene and n-butyl were added at 80 ° C. Acrylate 140.
A monomer mixture consisting of 0 g, 36.0 g of methacrylic acid, and 13.7 g of t-dodecylmercaptan was added dropwise over 126 minutes. After completion of the dropping, polymerization (second-stage polymerization) is carried out by heating and stirring for 60 minutes, and then cooled to 40 ° C., and latex (dispersion liquid of resin particles having a core shell structure containing a release agent in a core portion) I got This latex is referred to as “latex (1)”.

[Preparation Example of Colorant Dispersion] 9.2 g of sodium n-dodecyl sulfate was dissolved in 160 ml of ion-exchanged water with stirring. While stirring this solution, 20 g of carbon black “REGAL 330R” (manufactured by Cabot Corporation) is gradually added, and then a stirrer “CLEARMIX” (M · M) equipped with a high-speed rotating rotor.
A dispersion of the colorant particles (hereinafter, referred to as “colorant dispersion (1)”) was prepared by performing a dispersion treatment using a technique (manufactured by Technic Co., Ltd.). The particle size of the colorant particles in the colorant dispersion liquid (1) was measured by using an electrophoretic light scattering photometer “ELS-8”.
As a result of measurement using "00" (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 112 nm.

[Production of Toner 1] 1250 g of the latex (1) obtained in the preparation example of latex, 2000 ml of ion-exchanged water, and the colorant dispersion liquid (1) obtained in the preparation example of the colorant dispersion liquid were used. Into a 5-liter four-necked flask equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device. After adjusting the internal temperature to 30 ° C., a 5 mol / liter aqueous sodium hydroxide solution was added to the solution to adjust the pH to 10.0. Next, an aqueous solution in which 52.6 g of magnesium chloride hexahydrate was dissolved in 72 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, heating was started, and the system was heated to 90 ° C. over 6 minutes (heating rate = 10 ° C. /
Minutes). In that state, "Coulter counter TA-II"
The particle size of the associated particles is measured at
At the time when the temperature reached m, particle growth was stopped by adding an aqueous solution in which 115 g of sodium chloride was dissolved in 700 ml of ion-exchanged water, and further, fusion was performed by heating and stirring at a liquid temperature of 92 ° C. ± 2 ° C. for 5 hours. Was continued. Thereafter, the mixture was cooled to 30 ° C. under the condition of 6 ° C./min, the pH was adjusted to 2.0 by adding hydrochloric acid, and the stirring was stopped. The formed associated particles were filtered, washed repeatedly with ion-exchanged water, and then dried with warm air at 40 ° C. to obtain colored particles.

The thus obtained colored particles of 100
1 part by mass of silica fine particles is externally added and mixed with the mass part by a Henschel mixer, and a toner obtained by salting out / fusing resin particles having a release agent included in a binder resin and colorant particles is used. Obtained. This is referred to as toner 1.

[Production of Toners 2 to 4] In the production of the toner 1, the shape factor and the shape factor were changed in the same manner except that the liquid temperature and the time for continuing the fusion after stopping the particle growth were variously changed. Of toner having different coefficients of variation. These are referred to as toners 2 to 4.

[Production of Toner 5] 100 parts of styrene / acrylic resin and carbon black "REGAL 330R"
10 parts (manufactured by Cabot Corporation) and Exemplified Compound (19) 10
Were dry-mixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, pulverized with a mechanical pulverizer, and classified with an airflow classifier to obtain colored particles by a pulverization method.

The thus obtained colored particles of 100
Was externally mixed with 1 part of silica fine particles using a Henschel mixer to obtain a toner by a pulverization method. This is referred to as toner 5.

[Production of Toner 6] In the production of toner 5, the toner was produced in the same manner as in the pulverization method except that the number of revolutions of the mechanical pulverizer and the amount charged into the pulverizer were adjusted in order to change the coefficient of variation of the shape factor. I got This is referred to as toner 6.

[Production of Toner 7] In the production of toner 5, in order to change the shape coefficient and the variation coefficient of the shape coefficient,
A toner was obtained by a pulverization method in the same manner except that the mechanical pulverizer was changed to a jet air pulverizer and the pulverization conditions were adjusted. This is referred to as toner 7.

[Production of Toner 8] In a four-necked flask equipped with a high-speed stirring device (TK homomixer), 710 parts of ion-exchanged water and 450 parts of a 0.1 mol / L aqueous solution of trisodium phosphate were added. This system was heated to 65 ° C., and 68 parts of a 1.0 mol / L calcium chloride aqueous solution was gradually added under stirring conditions at a rotation speed of 12,000 rpm to prepare an aqueous medium comprising a dispersion containing colloidal tricalcium phosphate. did.

On the other hand, 14 parts of carbon black "REGAL 330R" (manufactured by Cabot Corporation) was added to a monomer mixture composed of 160 parts of styrene and 40 parts of n-butyl acrylate, and the mixture was dispersed by a sand grinder. 60 parts of Exemplified Compound (19) was added to the resulting dispersion and dissolved at 80 ° C. 2,2 ′ as a polymerization initiator in this solution
A monomer composition was prepared by adding 10 parts of azobis (2,4-dimethylvaleronitrile).

The thus obtained monomer composition was
The monomer composition was gradually added to the aqueous medium under stirring conditions at a rotation speed of 12000 rpm to disperse the monomer composition in the aqueous medium. Next, the TK homomixer was replaced with a normal stirring blade, and a polymerization reaction was performed under a nitrogen stream at 67 ° C. and 200 rpm for 10 hours. At the end of the polymerization reaction, hydrochloric acid was added to remove tricalcium phosphate as a dispersion stabilizer, and then filtered, washed and dried to obtain colored particles.
To 100 parts of the thus obtained colored particles, 1 part of silica fine particles was externally added and mixed with a Henschel mixer to obtain a toner by a suspension polymerization method. This is referred to as toner 8.

For each of the toners 1 to 8 obtained as described above, the shape coefficient (average circularity), the coefficient of variation of the shape coefficient, and the number average particle diameter were measured. The results are shown in Table 1 below.

[0152]

[Table 1]

In Table 1, the shape factor of the toner is
Using “FPIA-2000” (manufactured by Toa Medical Electronics Co., Ltd.), sample analysis volume = 0.3 μl, number of detected particles = 15
It was measured under the condition of 00 to 5000 pieces.

<Examples 1 to 4 and Comparative Examples 1 to 6> A digital copying machine Konica 7033 manufactured by Konica was remodeled.
An image was formed using the developing device shown in FIG.

As a toner conveying member of the developing device, 25 mm
EPDM rubber roller (add carbon black,
A thin layer of nylon (volume resistivity of 10 ¹³ Ω · cm, layer thickness of 80 μm) is provided on the surface with a volume resistivity of 10 ⁵ Ω · cm, and the surface roughness is changed. did. The diameter of the toner replenishment auxiliary member was 20 mm. An elastic blade made of steel was used as the toner layer regulating member, and the contact pressure was 0.6 N / cm. The copying speed was changed to A4, 20 sheets / min (ppm), and the actual copying was evaluated. A laminated organic photoreceptor was used as the photoreceptor.

A recording material (also referred to as a transfer paper or an image support) used was a paper having a continuous weight of 55 kg, and an image was formed in the vertical direction.

As for the image forming conditions, a line drawing having a pixel ratio of 5% was used in a high-temperature and high-humidity environment (30 ° C., 85% RH) where filming is likely to occur, and printing of 100,000 sheets was performed intermittently. The printing method was used. The images at the initial stage and after 100,000 copies were evaluated. The image prints solid black, thin line image, halftone image, solid white image, image density, fog density,
The line width reproducibility, the presence or absence of unevenness in the halftone image, and the filming of the toner carrier surface were evaluated.

[Evaluation Method] (1) Image Density Using a Macbeth reflection densitometer “RD-918”, the absolute reflection density of a solid black portion was measured.

(2) Fog Density With respect to blank paper on which no printing has been performed, absolute image densities at 20 locations are measured using a Macbeth reflection densitometer "RD-918" and averaged to obtain a blank paper density. Next, the absolute image densities of 20 places were similarly measured and averaged for the white background portion of the evaluation formed image, and the value obtained by subtracting the white paper density from the average density was evaluated as the fog density.

(3) Line Width Reproducibility The line width of a line image corresponding to a 2-dot line image signal was measured by a print evaluation system "RT-2000" (manufactured by Yarman).

If both the line width of the first formed image and the line width of the 100,000th formed image are 200 μm or less and the change in the line width is 10 μm or less, fine line reproducibility is not a problem. It can be said that.

(4) Halftone Unevenness The halftone image unevenness was visually evaluated with the following rank.

Rank A: Uniform image without unevenness Rank B: Streak-like thin unevenness present Rank C: Several streak-like thin unevenness present (problematically practical) Rank D: Clear streak-like unevenness (5) Filming of Surface of Toner Carrier The surface of the toner carrier was visually observed every 10,000 sheets, and evaluated at the time of occurrence of filming.

The results are shown in Table 2 below.

[0165]

[Table 2]

As described above, according to the results of the evaluation, it can be understood that all of Examples 1 to 4 in the present invention have characteristics that can be put to practical use. However, Comparative Examples 1 to 6 outside the present invention have a problem in at least one of the characteristics.

That is, according to the image forming method of the present invention, a high quality image can be stably formed over a long period of time with excellent developability and fine line reproducibility.

[0168]

As described above, according to the present invention, there is provided an image forming method in which even when images are repeatedly formed for a long period of time, the chargeability and transportability of the toner during development are stable and the image quality is hardly deteriorated. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a developing device used for an electrostatic latent image developing method according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 electrophotographic photosensitive drum 12 rubber roller 13 steel elastic blade 14 sponge roller 15 stirring blade 16 non-magnetic one-component toner 17 toner tank

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiroyuki Yamada 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H005 AA06 AA15 AB03 FA06 2H077 AC04 AD06 AD13 AD17 AD23 CA04 EA14 EA15 EA16 FA01 FA13 FA22

Claims (2)

[Claims] 1. An image forming method in which a thin layer is formed on a surface of a toner carrier using a non-magnetic toner comprising at least a resin, a release agent, and a colorant, and is conveyed to a development area for development. Has a surface roughness of 1 to 10 μm,
Further, the image forming method is characterized in that the toner is a toner obtained by salting out / fusing resin particles having a release agent in a binder resin and a colorant. 2. An image forming method in which a thin layer is formed on the surface of a toner carrier using a non-magnetic toner comprising at least a resin, a release agent, and a colorant, and is conveyed to a development area for development. Has a surface roughness of 1 to 10 μm,
And a shape coefficient of the toner is 0.930 to 0.980, and a coefficient of variation of the shape coefficient is less than 10%.