JP2003173060A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology that uses transparent toner and faint color toner, enhances glossiness and transferability, improves gradation, and decreases toner consumption. <P>SOLUTION: The image forming device forms, on an image forming body, transparent toner images and color toner images overlaid in that order, and then transfers the images all at once onto a transfer material or an intermediate transfer member. In the image forming device, in the case where transparent toner that form the transparent toner images is flat toner in which the diameter Dt of the equivalent of a circle viewed in a direction where an projection area is the maximum is 5 to 15 (μm), thickness Ht is 1 to 4 (μm), and flatness Ft expressed by Dt/Ht is 2 to 6, an amount of the transparent toner attached to the area where the toner images are formed so as to be overlaid one on another on the image carrier is M/At (mg/cm<SP>2</SP>), and the density of the transparent toner is ρt (g/cm<SP>3</SP>), the following relationship, 0.02×ρt×Ht≤M/ At≤0.06×ρt×Ht, is satisfied. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used as a copying machine, a printer or the like.

[0002]

2. Description of the Related Art Recently, with the advent of the information age, the demand for office machines such as copying machines, printers, and facsimiles has increased rapidly, and now, the speed of copying machines, the improvement in image quality, etc. The characteristics of are now required. Further, with the spread of colorization in copying machines and the like, improvement of characteristics such as high speed and high image quality has become an important issue.

To improve the image quality of a copying machine or the like, it is necessary to improve the characteristics of the toner. Particularly, it is preferable to use a toner having a small particle size of 5 to 10 μm and a sharp particle size distribution. It has turned out to be important. Such a toner can be obtained by classifying a crude toner in the above particle size range even by a conventional pulverization and granulation method, but a large amount of toner is removed in the classifying step, so that the yield is low and the productivity is poor. There was a problem. Therefore, in recent years, a polymerized granulated toner obtained by polymerization by a suspension polymerization method or an emulsion polymerization method has been developed and is about to be put into practical use. The polymerized granulated toner has a relatively small particle size and a sharp particle size distribution, and high image quality can be achieved by using the polymerized granulated toner.

Further, as a method for improving the characteristics of the copying machine and the like, a method of forming an image using flat toner has been proposed. For example, Japanese Patent Application Laid-Open No. 5-127420 proposes a technique of a flat toner obtained by causing spherical toner particles dispersed in a dispersion medium to collide with a rotating disk at high speed. Further, in Japanese Patent Application Laid-Open No. 11-167226, spherical toner particles are collided with a rotating disk at a high speed to obtain a diameter of 5 to 10 μm.
m, the thickness is 0.5 to 3 μm, and the thickness / diameter ratio is 0.1 to 0.
The technology of flat toner for color in the range of 4 has been proposed. According to the above publications, by using the flat toner, the heat at the time of heat fixing is received by the flat surface of the toner particles, so that the heat efficiency becomes large, the fixing time can be shortened, and the speed of the copying machine can be increased. Is achieved. Further, when the flat toner is used for forming a color image, each color toner does not become bulky, and it is easy to obtain a high-quality image having smoothness and gradation like a silver salt photograph.

On the other hand, by forming a transparent toner layer between the colored toner image and the image forming body, the transferability to the image support or the intermediate transfer body is improved, or on the image support, on the colored toner. A technique of forming a transparent toner layer to improve glossiness after fixing is known.

However, a large amount of transparent toner is required in order to exert a sufficient effect, which is disadvantageous in terms of cost and may lead to cracking of the toner image due to bending, resulting in peeling from the image support. . The same thing can be said when light color toner and dark color toner are used to improve the image quality.

[0007]

Therefore, there is a demand for a technique capable of reducing the consumption amount of toner by using a transparent toner or a light-colored toner, while being able to enjoy the effect of improving glossiness and transferability. The present invention is to meet such a demand.

An object of the present invention is to provide a technique in which transparent toner or light-color toner is used and the effects such as improvement in glossiness, transferability, and gradation are obtained, and the toner consumption is reduced. is there.

[0009]

Means for Solving the Problems The inventors of the present invention have diligently studied and found that the object of the present invention can be achieved by adopting any of the following constitutions.

[1] After forming a transparent toner image and a color toner image on an image forming body in this order, the transparent toner image and the color toner image are collectively formed on a transfer material or an intermediate transfer body. In the image forming apparatus for transferring, as the transparent toner forming the transparent toner image, the equivalent circle diameter Dt viewed from the direction in which the projected area is maximum is 5 to 15 (μm) and the thickness H is H.
Flatness Ft expressed by Dt / Ht, where t is 1 to 4 (μm)
Using a flat toner having a particle size of 2 to 6 and a toner adhesion amount M / At (mg / cm ² ) of the transparent toner in a region where the both toner images are superposed on the image forming body, and a density of the transparent toner is ρt. An image forming apparatus satisfying the following relation when (g / cm ³ ) is satisfied.

0.02 × ρt × Ht ≦ M / At ≦ 0.0
6 × ρt × Ht [2] As the colored toner forming the colored toner image, the equivalent circle diameter Dc viewed from the direction in which the projected area is maximum is 6 to 15 (μm), and the thickness Hc is 5 to 11 (μm). , Dc
The maximum value M / Ac _max (mg / cm ² ) of the adhered amount of the color toner formed on the image forming body and the density of the color toner are used by using a toner having a flatness Fc represented by / Hc of 2 or less. Is ρc (g / cm ³ ) and the number of colored toners when a plurality of colored toners are superposed is N, the image forming apparatus described in [1] is satisfied.

0.06 × ρc × Hc × N ≦ M / Ac _max
≦ 0.12 × ρc × Hc × N [3] The equivalent circle diameter Dt of the transparent toner and the equivalent circle diameter Dc of the colored toner satisfy the following relationship: [1] or [2] Image forming device.

Dc <Dt [4] The image forming apparatus as described in [1] or [2], wherein the thickness Ht of the transparent toner and the thickness Hc of the colored toner satisfy the following relationship.

Ht <Hc [5] After forming a color toner image and a transparent toner image on the image forming body in this order, the color toner image and the transparent toner image are collectively transferred onto a transfer material or an intermediate transfer. In an image forming apparatus for transferring onto a body, the transparent toner forming the transparent toner image has a circle equivalent diameter Dt of 5 to 15 (μm) and a thickness Ht of 1 to 4 when viewed from the direction in which the projected area is maximum.
(Μm), a flat toner having a flatness Ft represented by Dt / Ht of 2 to 6 is used, and the adhesion amount M / of the transparent toner in the area where the both toner images are superposed and formed on the image forming body. At (mg / cm ² ), the density of the transparent toner is ρt
An image forming apparatus satisfying the following relation when (g / cm ³ ) is satisfied.

0.02 × ρt × Ht ≦ M / At ≦ 0.0
6 × ρt × Ht [6] As the colored toner forming the colored toner image, the equivalent circle diameter Dc viewed from the direction in which the projected area is maximum is 6 to 15 (μm), and the thickness Hc is 5 to 11 (μm). , Dc
The maximum value M / Ac _max (mg / cm ² ) of the adhered amount of the color toner formed on the image forming body and the density of the color toner are used by using a toner having a flatness Fc represented by / Hc of 2 or less. Is ρc (g / cm ³ ) and the number of colored toners when a plurality of colored toners are superposed is N, the image forming apparatus described in [5] is satisfied.

0.06 × ρc × Hc × N ≦ M / Ac _max
≦ 0.12 × ρc × Hc × N [7] The circle equivalent diameter Dt of the transparent toner and the circle equivalent diameter Dc of the colored toner satisfy the following relationship [5] or [6]. Image forming device.

Dc <Dt [8] The image forming apparatus as described in [5] or [6], wherein the thickness Ht of the transparent toner and the thickness Hc of the colored toner satisfy the following relationship.

Ht <Hc

[9] After forming a light-color toner image and a dark-color toner image of similar colors on the image forming body in this order, the light-color toner image and the dark-color toner image are collectively formed on a transfer material or an intermediate transfer member. In the image forming apparatus for transferring the image onto the upper surface, the light-colored toner forming the light-colored toner image has a circle equivalent diameter Dl of 5 to 15 (μm) and a thickness Hl of 1 to 4 (μm) as viewed from the direction in which the projected area is maximum. ), The flatness Fl represented by Dl / Hl is 2
Using flat toner is 6, the two toner images of light color toner in a region which is formed by superimposing on the image forming body deposition amount ^{M / Al (mg / cm 2} ), the density of the light-colored toner Lowell (g / Cm ³ ), the image forming apparatus satisfies the following relationship.

0.02 × ρl × Hl ≦ M / Al ≦ 0.0
6 × ρl × Hl [10] As the dark color toner forming the dark color toner image, the equivalent circle diameter Dd viewed from the direction in which the projected area is maximum is 6 to 15 (μm), and the thickness Hd is 5 to 11 ( μm), Dd
The maximum value M / Ad _max (mg / cm ² ) of the adhered amount of the color toner formed on the image forming body and the density of the color toner are used by using a toner having a flatness Fd represented by / Hd of 2 or less. Is defined as ρd (g / cm ³ ), the following relation is satisfied.

The image forming apparatus according to [9].

0.06 × ρd × Hd ≦ M / Ad _max ≦
0.12 × ρd × Hd [11] The equivalent circle diameter Dl of the light color toner and the equivalent circle diameter Dd of the dark color toner satisfy the following relationship.

The image forming apparatus according to [9] or [10].

Dd <Dl [12] The thickness Hl of the light color toner and the thickness Hd of the dark color toner satisfy the following relationship.

The image forming apparatus according to [9] or [10].

Hl <Hd [13] After a plurality of color toner images and transparent toner images are formed on the image forming body, the transparent toner images are transferred to the intermediate transfer body so as to be lower layers, and then collectively. In an image forming apparatus for transferring onto a transfer material, the transparent toner forming the transparent toner image has a circle equivalent diameter Dt of 5 to 15 (μm) and a thickness Ht of 1 to 4 when viewed from the direction in which the projected area is maximum. (Μ
m), a flat toner having a flatness Ft represented by Dt / Ht of 2 to 6 is used, and the transparent toner adhesion amount M / At (m
g / cm ² ) and the density of the transparent toner is ρt (g / cm ³ ), an image forming apparatus satisfying the following relationship.

0.02 × ρt × Ht ≦ M / At ≦ 0.0
6 × ρt × Ht [14] As the colored toner forming the colored toner image, the equivalent circle diameter Dc viewed from the direction in which the projected area is maximum is 6 to 15 (μm), and the thickness Hc is 5 to 11 (μm). , Dc
The image forming apparatus according to [13], wherein a toner having a flatness Fc represented by / Hc of 2 or less is used.

[15] Equivalent circle diameter Dt of the transparent toner
And the equivalent circle diameter Dc of the colored toner satisfy the following relationship: [13] or [14].

Dc <Dt [16] The image forming apparatus as described in [13] or [14], wherein the thickness Ht of the transparent toner and the thickness Hc of the colored toner satisfy the following relationship.

Ht <Hc That is, a transparent toner or a light-colored toner is used as a specific flat type toner, and the amount of the toner used is appropriately selected so that the covering power is exerted on the image forming body, the image support, and the intermediate body. It was found that the transfer member, the color toner image, etc. can be effectively covered. As a result, the amount of transparent toner or light color toner used can be significantly reduced,
The present invention has been completed.

Further, when the flat transparent toner or the light color toner of the present invention is used, it is also clear that it is preferable to use a near spherical toner as the colored toner or the dark color toner in consideration of the image quality. It was

Since the present invention has a slightly different basic structure, the first invention has the structure of [1] to [4] and the first structure has the structure of [5] to [8]. Two inventions,

A structure having the configurations [9] to [12] is a third invention, [1
Those having the configurations of 3] to [16] may be referred to as a fourth invention.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The specific examples of the flat toner, spherical toner, photoconductor, intermediate transfer member, and image forming apparatus of the present invention will be described below.

<Construction of Flat Toner and Spherical Toner of the Present Invention> If the particle size of the toner is too small, it easily scatters and is harmful if inhaled into the human body. If it is too large, it causes deterioration of image quality. It was already known that there is.

When the flatness d / t represented by the ratio of the equivalent circle diameter d (μm) of the toner and the thickness t is close to 1.0,
The characteristics as a flat toner cannot be exhibited. However, it has been known that if the flatness is too large, the toner is likely to be crushed, and the background stain is likely to occur. However, in order to achieve the object of the present invention,
Furthermore, it has been found that the range must be strictly defined.

The flat toner for achieving the object of the present invention has the following characteristics. The equivalent circle diameter d (μm) is 5 ≦ d ≦ 15 and the thickness t (μm) is 1 ≦ t ≦ 4 when viewed from the direction in which the projected area of the toner is maximum, and the equivalent circle diameter d and the thickness t are The toner flatness d / t represented by the ratio is 2 ≦ d / t ≦ 6.

FIG. 1 shows a plan view and a side view of the flat toner of the present invention. P1 is the flat toner of the present invention, and P2 is the projected area of the flat toner when viewed from the direction in which the projected area of the flat toner is maximum. A circle having the same area is represented, d is a diameter (equivalent circle diameter) (μm) of the circle P2, and t is a maximum thickness (μ of the flat toner as viewed from a direction perpendicular to the projection direction of the flat toner P1.
represents m). In the present invention, as a method of expressing the size of the flat toner, the reason why it is determined from the equivalent circle diameter d (μm) of the projection surface when viewed from the direction in which the projection area of the flat toner is maximum is This means that the toner is measured in a lying state on a smooth measurement surface.

The equivalent circle diameter d (μm) and the thickness t (μm) when viewed from the direction in which the projected area of the flat toner according to the present invention is maximum can be measured, for example, by the following method. That is, the flat toner is uniformly dispersed and adhered so as to lie on a smooth measurement surface, and the flat toner particles 500
About individual, color laser microscope "VK-8500"
(Keyence Co., Ltd.) magnifying 500 times,
The circle-equivalent diameter d (μm) and the maximum height (thickness) t (μm) of 0 toner particles can be measured and calculated from their arithmetic average values.

(Toner Production Method) In order to produce the flat toner of the present invention, resin particles (containing a colorant and the like if necessary) obtained by a conventional pulverization and granulation method are spherically shaped by, for example, a spray drying method. It may be formed by applying heat and mechanical shearing force to the resin particles that have been made into a spherical shape and subjected to a flattening treatment. However, the resin particles obtained by the pulverization and granulation method have a broad particle size distribution and an irregular shape, and a large amount of unqualified resin particles are removed by a classification operation, resulting in poor productivity. However, it is preferable to manufacture by a polymerization granulation method.

That is, the flat toner of the present invention uses resin particles obtained by fusing resin fine particles prepared by an emulsion polymerization method, a suspension polymerization method or the like in an aqueous medium, or directly.
Using resin particles prepared by the suspension polymerization method, these resin particles are further heat-treated to be spheroidized, and the spheroidized resin particles are subjected to a flattening treatment by applying heat and mechanical shearing force. Is preferred.

The resin particles (former) obtained by fusing resin fine particles prepared by the emulsion polymerization method or suspension polymerization method in an aqueous medium have a uniform surface, and a flat toner obtained from the resin particles is also available. It also has the advantage that the surface is uniform. Further, since the resin particles (latter) directly prepared by the suspension polymerization method are also spherical, the surface shape becomes smooth even when the resin particles are flattened to obtain a flat toner. However, the resin particles obtained by fusing the former resin fine particles have a sharper particle size distribution than the latter resin particles obtained directly by suspension polymerization, so the former resin fine particles are fused in an aqueous medium. It is more preferable to use resin particles obtained by deposition.

As the method for producing the flat toner of the present invention, the former production method using resin particles obtained by fusing resin particles in an aqueous medium will be described below.

<Polymerizable Monomer> As the polymerizable monomer as the material of the flat toner of the present invention, a radical polymerizable monomer is a main constituent component, and a crosslinking agent is added if necessary. In addition, at least one kind of radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group may be contained.

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

Specifically, aromatic vinyl monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers. A monomer, a halogenated olefin-based monomer or the like can be used. Examples of aromatic vinyl monomers include styrene, o-methylstyrene, m-
Methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene,
p-ethylstyrene, pn-butylstyrene, pt
ert-butyl styrene, pn-hexyl styrene,
pn-octyl styrene, pn-nonyl styrene,
pn-decylstyrene, pn-dodecylstyrene,
Examples thereof include styrene-based monomers such as 2,4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
Examples of the (meth) acrylic acid ester-based monomer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid. Butyl, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like can be mentioned. Examples of vinyl ester-based monomers include vinyl acetate, vinyl propionate, and vinyl benzoate. Examples of vinyl ether-based monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, and the like. Mono-olefin monomers include ethylene, propylene,
Examples include isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like. Examples of the diolefin-based monomer include butadiene, isoprene and chloroprene. As the halogenated olefin-based monomer,
Examples thereof include vinyl chloride, vinylidene chloride, vinyl bromide and the like.

(2) Cross-linking agent As the cross-linking agent added to improve the properties of the toner, a radical-polymerizable cross-linking agent is used. Examples of the radical-polymerizable cross-linking 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.

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 monomers, although it depends on its characteristics.

(3) Radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group Radical polymerizable monomer having an acidic group or radical polymerizable monomer having a basic group For example, an amine compound such as a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, a primary amine, a secondary amine, a tertiary amine, or a quaternary ammonium salt may be used. it can.

As the radically polymerizable monomer having an acidic group, for example, a carboxyl group-containing monomer, a sulfonic acid group-containing monomer and the like can be used. Examples of the carboxylic acid group-containing monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid monooctyl ester and the like, and also a sulfonic acid group containing As a monomer,
Examples thereof include styrene sulfonic acid, allyl sulfosuccinic acid, and octyl allyl sulfosuccinate. These may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium.

As the radical-polymerizable monomer having a basic group, for example, amine compounds such as primary amine, secondary amine, tertiary amine and quaternary ammonium salt can be used. . Specifically, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and quaternary ammonium salts of these four compounds, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxy. Propyltrimethylammonium salt, acrylamide, N-
Butyl acrylamide, N, N-dibutyl acrylamide, piperidyl acrylamide, 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. The radical polymerizable monomer having an acidic group or the radical polymerizable monomer having a basic group is preferably used in the range of 0.1 to 15% by mass based on the whole radical monomer.

<< Chain Transfer Agent >> A commonly used chain transfer agent can be used for the purpose of adjusting the molecular weight. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, and styrene dimer.

<< Polymerization Initiator, Dispersion Stabilizer, Surfactant >>
When resin fine particles are prepared by a so-called emulsion polymerization method and then the resin fine particles are salted out and fused to form resin particles as toner base particles, a water-soluble radical polymerization initiator is used. Examples of the water-soluble radical polymerization initiator include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-).
Cyanovaleric acid and salts thereof, 2,2′-azobis (2-amidinopropane) salt, etc.), peroxide compounds and the like. These radical polymerization initiators can be used as a redox-type initiator in combination with a reducing agent if necessary. By using the redox type initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and further shortening of the polymerization time can be expected.

The amount of the polymerization initiator added is determined by the molecular weight of the resin that will be the final toner, but is generally 0.1 to 10% by mass, preferably 0 based on the radical-polymerizable monomer. 2 to 5% by mass. The polymerization temperature may be selected at any temperature as long as it is at least the minimum radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C to 90 ° C is used. However, it is also possible to carry out the polymerization at room temperature or higher by using a combination of a polymerization initiator started at room temperature, for example, hydrogen peroxide-reducing agent (ascorbic acid etc.).

The surfactant that can be used in the emulsion polymerization is not particularly limited, but it is necessary to disperse the above-mentioned radically polymerizable monomer in an aqueous medium as oil droplets. An ionic surfactant can be mentioned as a suitable example. As the ionic surfactant, sulfonates (sodium dodecylbenzene sulfonate, sodium arylalkyl polyether sulfonate, 3,3-disulfone diphenylurea-4,4-
Sodium 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.), sulfate ester salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, caprylic acid) Sodium, sodium caproate, potassium stearate, calcium oleate, etc.) and the like. In addition to these, nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester. Etc. can be mentioned.

Although these surfactants are mainly used as an emulsifier during emulsion polymerization, they may be used for other steps or purposes.

When resin fine particles are prepared by a so-called suspension polymerization method and then the resin fine particles are salted out and fused to form resin particles as toner base particles, an oil-soluble radical polymerization initiator is used. It is preferable. Specific examples of the oil-soluble radical polymerization initiator include benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, cumene hydroperoxide, acetyl peroxide, and propionyl. Peroxides such as peroxides, 2,2'-azobisisobutyronitrile, 2,2 '
-Azobis (2,4-valeronitrile), 2,2'-azobis-2-methylvaleronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, and other azobis-based polymerization initiators. it can. The addition amount of the polymerization initiator is determined by the molecular weight of the resin that becomes the final toner, but is generally 0.
It is 1 to 10% by mass, preferably 0.2 to 5% by mass.

In the suspension polymerization method, a dispersion stabilizer is used by dispersing it in an aqueous medium. As the dispersion stabilizer, those that can be easily removed in the final stage of filtration and washing are preferable, and particularly, an inorganic sparingly water-soluble dispersion stabilizer is preferably used. Specifically, calcium carbonate, tricalcium phosphate, aluminum oxide, barium carbonate, magnesium carbonate, barium sulfate, aluminum hydroxide, titanium oxide,
Examples thereof include silicon oxide and iron hydroxide, and a particularly preferable dispersion stabilizer is tricalcium phosphate. In addition,
In addition to this poorly water-soluble inorganic dispersion stabilizer, a small amount of surfactant may be used as a dispersion aid. In this case, nonionic
Any of anionic type, cationic type and amphoteric type can be used, but anionic type surfactant is more preferable.

The dispersion stabilizer is preferably used in an amount of about 1 to 10% by mass based on the oil phase component to be dispersed. When it is less than this range, dispersion stability is lowered and particle agglomeration occurs. When it is more than this range, dispersion is promoted and small particle size components are excessively generated. . Further, the surfactant is 0.05 to 1 with respect to the inorganic dispersion stabilizer.
It is preferable to add about mass%. If it is less than this range, the effect of improving dispersion stability cannot be exhibited, and if it is used beyond this range, emulsification of the radically polymerizable monomer occurs, and so-called latex particles are present in the system. Occurs, and there is a problem that the particle size distribution spreads,
It becomes difficult to remove the surfactant, and there is a problem that water adsorption occurs.

<< Colorant >> When a colorant is used instead of the transparent toner, a conventionally known inorganic pigment, organic pigment or dye can be used as the colorant. When a light color toner is used in addition to the normal dark color toner (toner having a normal density), the colorant concentration thereof is 1 of that of the dark color toner (the colorant concentration is 3 to 15 mass% of the total toner mass). /
A concentration of about 10 to 1/3 is suitable.

Specific examples of the inorganic pigment include carbon black such as furnace black, channel black, acetylene black, thermal black and lamp black as a black pigment, and magnetic such as magnetite and ferrite. Powder is also used.

Specific examples of the organic pigment include magenta or red pigments such as C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I.
Pigment Red 5, C.I. I. Pigment Red 6,
C. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 5
3: 1, C.I. I. Pigment Red 57: 1, C.I. I.
Pigment Red 122, C.I. I. Pigment Red 1
23, C.I. I. Pigment Red 139, C.I. I. Pigment Red 144, C.I. I. Pigment Red 14
9, C.I. I. Pigment Red 166, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178,
C. I. Pigment Red 222 and the like. As an orange or yellow pigment, C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 4
3, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14,
C. 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 and the like. Pigments for green or cyan include C.I. I. Pigment Blue 15, C.I.
I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 16, C.I.
I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

Specific examples of the dye include 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,
No. 93, No. 95, etc., and a mixture thereof can also be used.

These inorganic pigments, organic pigments, and dyes may be used alone or in combination of two or more as desired. The amount of pigment added is 2 to 20% by mass, preferably 3 to 15% by mass, based on the total toner, for a normal toner (the same applies to dark color toner). When the toner is used as a magnetic toner, the above-mentioned magnetite is usually added, and in this case, from the viewpoint of imparting predetermined magnetic characteristics, it is preferable to add 20 to 60% by mass to the toner.

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

<< Other Internal Additives >> In addition to the colorant, other components such as a release agent and a charge control agent may be added to the toner. As the release agent, various known ones can be used, for example, olefin wax such as low molecular weight polypropylene and polyethylene, modified products thereof, natural wax such as carnauba wax and rice wax, and fatty acid bisamide. Examples of the amide waxes include Similarly, various known charge control agents can be used, for example, nigrosine dye, metal salt of naphthenic acid or higher fatty acid, alkoxylated amine,
Examples thereof include quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof. It is preferable that the particles of the release agent and the charge control agent have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.

<External Additive> A so-called external additive may be added to the flat toner used in the present invention for the purpose of improving fluidity and cleaning property.
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 ones can be used. Specifically, silica, titanium, alumina fine particles and the like can be preferably used. The inorganic fine particles are preferably hydrophobic. Specifically, as the silica fine particles, for example, commercially available products R-805, R-976, R-974, and R-97 manufactured by Nippon Aerosil Co., Ltd.
2, R-812, R-809, Hovst HVK-
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 commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B and M manufactured by Teika.
T-500BS, MT-600, MT-600SS, J
A-1, commercial product TA-300SI, manufactured by Fuji Titanium Co., Ltd.
A-500, TAF-130, TAF-510, TAF
-510T, commercial products IT-S, IT-O manufactured by Idemitsu Kosan Co., Ltd.
A, IT-OB, IT-OC, etc. are mentioned. Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products TTO manufactured by Ishihara Sangyo Co., Ltd.
-55 etc. are mentioned.

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. Specifically, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

As the lubricant, for example, zinc stearate, aluminum, copper, magnesium, calcium and the like salts, oleic acid zinc, manganese, iron, copper, magnesium and the like salts, palmitic acid zinc, copper and magnesium, Examples thereof include salts of calcium and the like, salts of zinc linoleic acid, salts of calcium and the like, and metal salts of higher fatty acids such as salts of zinc and calcium of ricinoleic acid.

The addition amount of these external additives is preferably about 0.01 to 5% by mass with respect to the toner.

<< Manufacturing Process >> The manufacturing process of the flat toner preferably used in the present invention includes the steps of manufacturing resin particles as toner base particles, the step of spheroidizing the resin particles, and the spherical resin particles. And a step of adding an external additive to the particles subjected to the flattening treatment.

<Production Process of Resin Particles> As described above, the production of resin particles as the toner base particles is performed by fusing resin fine particles prepared by a polymerization method such as emulsion polymerization or suspension polymerization in an aqueous medium. It is preferably used.

When the resin fine particles prepared by a polymerization method such as emulsion polymerization or suspension polymerization are fused in an aqueous medium to produce resin particles as a toner base, the production process is emulsion polymerization, suspension polymerization or the like. Polymerization step for preparing resin fine particles by the polymerization method of, the step of obtaining resin particles by fusing resin fine particles in an aqueous medium using the obtained resin fine particle dispersion, obtained by fusing in an aqueous medium It comprises a step of further heating the resin particles to make them spherical, and a washing step of removing the surfactant and the like by filtering from an aqueous medium. Here, the aqueous medium is composed of water as a main component, and indicates a water content of 50% by mass or more. Examples of substances other than water include organic solvents that dissolve in water, such as methanol and
Examples of the solvent include ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, but an organic solvent that does not dissolve the resin, preferably an alcohol-based organic solvent such as methanol, ethanol, isopropanol, or butanol is preferable.

The resin particles as the toner base particles may optionally contain a colorant, a release agent, a charge control agent and the like as toner constituents. These toner constituents are polymerized in the polymerization step for preparing resin fine particles. In the resin fine particles, or after preparing resin fine particles not containing these toner constituents, a liquid obtained by dispersing or dissolving a colorant, a release agent, a charge control agent or the like in the dispersion liquid of the resin fine particles. Although any of the methods of adding and melting the resin particles in the aqueous medium may be included in the resin particles, it is preferable to include the release agent in the polymerization step, and the colorant is included in the step of melting the resin particles. Preferably.

The polymerization step for preparing the resin fine particles is carried out, for example, by mechanical energy of a solution prepared by dissolving a releasing agent in a polymerizable monomer into an aqueous medium in which a surfactant having a critical micelle concentration or less is dissolved. A method in which oil droplets are dispersed and a water-soluble polymerization initiator is added to this dispersion to perform radical polymerization can be mentioned. In this case, an oil-soluble polymerization initiator may be added to the monomer before use. The disperser for dispersing the oil droplets is not particularly limited, and examples thereof include Clearmix, an ultrasonic disperser, a mechanical homogenizer, Manton-Gaulin, and a pressure homogenizer.

As a method for fusion, a method is preferably used in which the resin fine particles produced in the polymerization step and, if necessary, the colorant particles are fused while salting out in an aqueous medium.

In the salting-out / fusing step, a salting-out agent composed of an alkali metal salt, an alkaline earth metal salt or the like is coagulated in water containing the resin fine particles and the colorant particles to a concentration higher than the critical coagulation concentration. This is a step of adding salt as an agent and then heating it to a temperature not lower than the glass transition point of the resin fine particles to promote salting out and simultaneously perform fusion. In this step, a method may be used in which an organic solvent that is infinitely soluble in water is added to substantially lower the glass transition temperature of the resin fine particles to effectively perform fusion.

Examples of the alkali metal salt and the alkaline earth metal salt which are salting out agents include lithium, potassium and sodium as the alkali metal, and magnesium, calcium, strontium, barium and the like as the alkaline earth metal. And preferably potassium, sodium, magnesium, calcium, or barium. Examples of the salt include chlorine salt, bromine salt, iodine salt, carbonate salt, and sulfate salt. Examples of the organic solvent infinitely soluble in water include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, and acetone. However, methanol, ethanol, 1-propanol having 3 or less carbon atoms, The alcohol of 2-propanol is preferable, and 2-propanol is particularly preferable.

The colorant particles are prepared by dispersing the colorant in an aqueous medium having a surfactant concentration of the critical micelle concentration (CMC) or more. The disperser at the time of dispersing the colorant is not particularly limited, but is preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as Manton-Gaulin or a pressure homogenizer, a sand grinder, a medium type such as a Getzmann mill or a diamond fine mill. A disperser can be used. The colorant may be used after surface modification.In this case, the surface modifier is added to the dispersion liquid in which the colorant is dispersed, the temperature is raised to carry out the reaction, and after the reaction is completed, filtration and washing are performed. Then, the pigment treated with the surface modifier can be obtained by drying.

When the fusion is carried out by salting-out / fusion, it is preferable that the time after leaving the salting-out agent is left as short as possible. The reason for this is not clear, but depending on the standing time after salting out, the aggregation state of the particles fluctuates, the particle size distribution becomes unstable, and the surface properties of the fused resin particles fluctuate. Occurs. The temperature at which the salting-out agent is added is preferably below the glass transition temperature of the resin particles. If the temperature at which the salting-out agent is added is equal to or higher than the glass transition temperature of the resin fine particles, salting out / fusion of the resin fine particles will proceed rapidly, but the particle size cannot be controlled and particles having a large particle size will be obtained. May occur. The range of this addition temperature may be not higher than the glass transition temperature of the resin, but is generally 5 ° C to 55 ° C, preferably 10 ° C to 45 ° C.
℃.

After adding the salting-out agent at a temperature not higher than the glass transition temperature of the resin fine particles, it is preferable to use a method of raising the temperature as quickly as possible and heating the glass transition temperature not lower than the glass transition temperature of the resin fine particles. The heating rate at this time is preferably 1 ° C./minute or more, and the time until the temperature is raised is preferably less than 30 minutes, particularly preferably less than 10 minutes. The upper limit of the rate of temperature increase is not particularly clear, but from the viewpoint of suppressing the generation of coarse particles due to the rapid progress of salting out / fusion, 15 ° C./min or less is preferable. As a particularly preferable form, by allowing salting out / fusion to proceed continuously even when the glass transition temperature is reached or higher, it is possible to effectively advance fusion with particle growth.

Then, in the process of continuously advancing salting-out / fusion, the temperature of the resin particles grown by fusion is monitored, and when the desired size is reached, the temperature is further raised to be spherical. Is preferred. By this spheroidization, the flatness of the flattened toner obtained by the flattening process described later has a large circularity described later, and the toner image on the photoconductor tends to adhere to the surface of the photoconductor in a lying state.

The resin particles thus obtained preferably have a volume average particle diameter of 3 to 9 μm. The volume average particle diameter of the resin particles can be measured using a Coulter Counter TA-II, a Coulter Multisizer, SLAD1100 (manufactured by Shimadzu Corporation, laser diffraction particle size measuring apparatus), or the like.
When Coulter Counter TA-II and Coulter Multisizer are used, the values measured using a particle size distribution in the range of 2.0 to 40 μm using an aperture having an aperture diameter of 100 μm are shown.

The shape of the resin particles obtained by fusing and spheroidizing is preferably such that the average value (average circularity) of the shape factors represented by the following equation is 0.95 to 1.00.

Shape factor = (circumferential length of circle determined from equivalent circle diameter) / (perimeter of particle projection image) Further, the distribution of the shape factor is preferably sharp, and the standard deviation of circularity is 0.10 or less. The CV value of the shape factor calculated by the following equation is preferably less than 10%.

CV value = (standard deviation of circularity) / (average circularity) × 100 The above shape factor was taken with a scanning electron microscope to photograph a photograph of resin particles of 500 resin particles. Image analysis device "SCANNINGIMAG
This can be calculated by analyzing the photographic image using "E ANALYSER" (manufactured by JEOL Ltd.), measuring the circularity, and calculating the arithmetic mean value. As a simple measuring method, "FPIA-1000" (manufactured by Toa Medical Electronics Co., Ltd.) can be used for measurement.

The resin particle dispersion is cooled at the stage where particles having a desired particle size and shape are obtained, and the obtained particles are filtered from an aqueous medium and washed with water to obtain wet cake resin particles.

When used as a normal spherical toner, an external additive is added if necessary, but it is used as it is without any special processing. However, when it is desired to use it as a flat toner, it is necessary to flatten it by performing the following processing, for example.

<Flatization Step> The flattening treatment of the resin particles is
It can be performed by applying heat and mechanical shearing force to the liquid in which the resin particles are dispersed. Specifically, the wet cake-like resin particles obtained above are redispersed in an aqueous medium, and in this dispersion, polyethylene, polymethylmethacrylate, polytetrafluoroethylene, polystyrene having a particle size of about 100 μm to 2000 μm, Polystyrene
Synthetic resin fine particles composed of acrylonitrile copolymer,
A method of adding glass beads, zirconia beads or the like as a medium and then stirring the dispersion while heating it at a temperature not lower than the glass transition point of the resin particles is preferably used. On this occasion,
A viscosity increasing agent such as methyl cellulose may be added to the dispersion liquid of the resin particles to increase the viscosity of the resin particle dispersion liquid, and an antifoaming agent may be added if necessary.

As an apparatus for heating and stirring the resin particle dispersion, a conventionally known disperser can be used, and specific examples thereof include a medium grinder, a sand grinder, a Getzman mill, a diamond fine mill and the like. .

The temperature of the dispersion must be above the glass transition point of the resin particles, and the upper limit is below the treatment temperature for salting out / fusing the resin particles in the resin particle manufacturing process or It is preferable that the temperature is not higher than the melting point of the release agent contained in the resin particles, and the flattening treatment temperature is preferably in the range of not less than the glass transition point of the resin particles and not more than + 20 ° C. of the glass transition point. If the flattening treatment temperature is too low, the flattening treatment of the resin particles is not sufficiently performed, and if the flattening treatment temperature is too high, the resin particles aggregate or the release agent contained in the resin particles elutes from the resin particles. To do The flattening time of the resin particles depends on the temperature of the resin particle dispersion, the particle size and specific gravity of the medium used, the stirring speed, the shape of the stirring tank, etc., but is usually about 10 minutes to 10 hours.

The resin particles in the dispersion liquid are subjected to the flattening treatment by the above heating and stirring treatment. In order to make the surface of the flattened resin particles smooth, a medium such as a sieve is used to remove the medium from the resin particle dispersion liquid. After separating, the dispersion may be subsequently heated and stirred. The heating temperature in this case is preferably in the same range as the flattening temperature.

After the flattening treatment, the resin particle dispersion is cooled, and the flattened resin particles are filtered, washed and dried to obtain a flat toner.

The shape of the flat toner of the present invention is almost uniquely determined by the particle size and shape of the resin particles as the toner base particles before the flattening treatment and the degree of flattening in the subsequent flattening step. The degree of flattening can be easily controlled by changing the flattening processing time.

FIG. 2 is a diagram showing an example of the relationship between the flattening processing time and the shape of the flattened toner, which is shown in FIGS.
(C) is 3.0 μm as toner base particles,
FIG. 6 is a diagram showing changes in equivalent circle diameter and thickness with respect to flattening time when flattening is performed using spherical particles of 6.5 μm and 8.5 μm. For example, the toner base particles have a particle size of 3.
When spherical particles of 0 μm are used, as shown in FIG. 2A, the equivalent circle diameter d and the thickness t are (3.
4 μm, 2.3 μm), (3.8 μm, 1.9 μm),
(4.3 μm, 1.4 μm), (4.8 μm, 1.2 μ
m), (5.1 μm, 1.0 μm), (5.5 μm,
2 (b) when spherical particles having a particle size of 6.5 μm are used as the toner base particles.
As shown in, the equivalent circle diameter d and thickness t
Are (7.4 μm, 5.0 μm), (8.2 μm, 4.1
μm), (9.4 μm, 3.1 μm), (10.3 μm
m, 2.6 μm), (11.1 μm, 2.2 μm),
(11.8 μm, 2.0 μm), ..., When spherical particles having a particle size of 8.5 μm were used as the toner base particles, as shown in FIG. The equivalent diameter d and the thickness t are (9.7 μm, 6.5 μm), (1
0.7 μm, 5.4 μm), (12.3 μm, 4.1 μm
m), (13.5 μm, 3.4 μm), (14.5 μm
m, 2.9 μm), (15.4 μm, 2.6 μm),
.. changes.

<Developer> The flat toner according to the present invention is
It can be used as it is as a non-magnetic or magnetic one-component developer, but it is preferably mixed with a carrier and used as a two-component developer.

As the particles used as a carrier, conventionally known magnetic particles such as metals such as iron, ferrite and magnetite and alloys of these metals with metals such as aluminum and lead can be used, and ferrite particles are particularly preferable. Used. The volume average particle diameter of the magnetic particles is 15 to 100 μm, and more preferably 25 to 60 μm. The volume average particle diameter of the carrier is typically measured by a laser diffraction type particle size distribution measuring apparatus "HELOS" equipped with a wet disperser (SYMPATIC (SYMP).
(Made by ATEC)). As the carrier, the above magnetic particles can be used as they are,
A resin-coated carrier or a so-called resin-dispersed carrier in which magnetic particles are dispersed in the resin is preferable. The resin composition for coating is not particularly limited, but for example, an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used.
The resin for forming the resin-dispersed carrier is not particularly limited, and known resins can be used,
For example, styrene / acrylic resin, polyester resin,
Fluorine-based resin, phenolic resin and the like can be used.

<Image Forming Body> The image forming body in the present invention is
Typically, it is an electrophotographic photoreceptor (also simply referred to as a photoreceptor).

The electrophotographic photosensitive member is obtained by laminating or vapor-depositing a thin metal layer of aluminum, palladium or the like on a support such as a metal plate or metal drum of aluminum or stainless steel, paper or plastic film, or paper or plastic film. Of a conductive polymer, indium oxide, tin oxide or the like coated or vapor-deposited on a support of a photo-conductive substance is vapor-deposited on the conductive support or the photo-conductive substance is dispersed and contained in a binder. It is obtained by providing a photosensitive layer coated with a liquid and a protective layer on the photosensitive layer.

(Photosensitive layer) As the photosensitive layer of the photosensitive material of the present invention, an inorganic photosensitive material using selenium, amorphous silicone, cadmium sulfide, or the like, or an organic charge generating substance (CGM) and charge transport on the above-mentioned conductive support. An organophotoreceptor containing a substance (CTM) is used. In the case of the above-mentioned inorganic photoconductor, there is a method of polishing the surface with a hard abrasive such as cerium oxide, silicon oxide or zirconium oxide to finish the surface roughness of the photoconductor of the present invention. However, it is preferable to use an organic photoreceptor having excellent processability and excellent electrophotographic performance, and to form a rough surface by incorporating hard inorganic fine particles or organic fine particles described later in the surface layer of the organic photoreceptor. preferable.

The inorganic particles are preferably hydrophobized with a hydrophobizing agent such as titanium coupling agent, silane coupling agent, polymeric fatty acid or metal salt thereof.

In the present invention, of the organic and inorganic particles contained in the outermost surface layer of the photoreceptor, methylmethacrylate resin particles and silica particles are particularly preferably used. Furthermore, the hygroscopicity is small and the active hydroxyl group on the surface is small. Silica particles having a low content are preferably used.

In the present invention, these organic and inorganic particles are contained in at least the outermost surface layer of the photoreceptor together with the binder, but the ratio of the organic and inorganic particles in the outermost surface layer is usually 1 to 200% by mass, preferably the binder. Is used at 5-100% by weight. The outermost surface layer of the present invention is a layer located on the outermost surface of the photoreceptor.

The photosensitive layer of the photoreceptor of the present invention containing the above-mentioned organic and inorganic particles in the outermost surface layer may be an inorganic photoreceptor using selenium, amorphous silicon, cadmium sulfide, etc., but is preferable. Organic charge generation material (CG
M) and a charge transport material (CTM).

<< Charge Generating Material (CGM) and Charge Transporting Material (CTM) >> CG contained in the photosensitive layer of the photoreceptor of the present invention.
Examples of M include phthalocyanine pigments, polycyclic quinone pigments, azo pigments, perylene pigments, indigo pigments, quinacridone pigments, azurenium pigments, squarylium dyes, cyanine dyes, pyrylium dyes, thiopyrylium dyes, xanthene dyes, triphenylmethane dyes, styryl dyes. Etc., and these CGMs are used alone or together with a suitable binder resin to form a layer.

The CTM contained in the photosensitive layer is as follows.
For example, oxazole derivative, oxadiazole derivative,
Thiazole derivative, thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative,
Imidazoline derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, benzidine compound, pyrazoline derivative, stilbene compound, amine derivative, oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, amino Examples thereof include stilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc. These CTMs are usually layered with a binder.

<< Binder >> As the binder resin contained in the charge generating layer (CGL), charge transporting layer (CTL), protective layer and the like having the above-mentioned laminated structure, polyester resin, polystyrene resin, methacrylic resin, acrylic resin, polychlorinated resin can be used. Vinyl resin, polyvinylidene chloride resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl acetate resin, styrene-butadiene resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-maleic anhydride copolymer resin, urethane resin, silicone resin, Epoxy resin, silicone-alkyd resin, phenol resin, polysilane resin, polyvinylcarbazole and the like can be mentioned.

<Intermediate Transfer Member> Generally, in electrophotography, the toner image formed on the photosensitive member is temporarily transferred onto the intermediate transfer member without being directly transferred to the transfer material, and the toner image on the intermediate transfer member is transferred. In some cases, the image may be re-transferred onto the transfer material. In this case, a high quality image can be formed by selecting and using an intermediate transfer member suitable for transferring the toner image. In particular, when a color image is formed by superposing a plurality of color toners, it is easier to obtain a good color image by using the intermediate transfer member.

Here, the quality of the transfer of the toner image between the intermediate transfer body and the transfer material is the same as the quality of the transfer of the toner image between the photoreceptor and the transfer material.

The intermediate transfer member of the present invention may have a drum shape, an endless belt shape or the like, but normally an endless belt shape is preferably used and has a surface roughness Ra '(center line average roughness) of 0.01. × a d / t ≦ Ra '≦ 0.5 , a volume resistivity of ^{10 8 ~10 1 5 Ω · cm} , a surface resistivity of 1
It is an endless belt having a thickness of 0 ⁸ to 10 ¹⁵ Ω / □, and a conductive material is dispersed in an engineering plastic such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, nylon alloy, etc. The outer surface of the semiconductive film substrate having a thickness of 1 to 0.5 mm was coated with fluorine having a thickness of 5 to 50 μm, preferably as a toner filming prevention layer.
A seamless belt having a layer structure is preferably used. In addition to this, the intermediate transfer body 14b has a thickness of 0.5 to 0.5 obtained by dispersing a conductive material in silicone rubber or urethane rubber.
A 2.0 mm semi-conductive rubber belt can also be used.

As a preferable manufacturing method for manufacturing the above-mentioned flexible endless belt-shaped intermediate transfer member, there is, for example, a centrifugal polymerization method. According to the above-mentioned centrifugal polymerization method, particularly preferably, a resin monomer of polyimide or polyamide-imide is put in a cylinder having an inner surface having a surface roughness corresponding to the surface roughness Ra 'in the present invention, and the cylinder is rotated under heating. Then, a resin monomer is adhered and polymerized on the inner surface of the cylinder by the action of centrifugal force to manufacture an intended endless belt-shaped intermediate transfer member. Further, a solution prepared by dissolving a resin in an organic solvent is put in a cylinder, the cylinder is rotated under heating, and the resin solution is applied to the inner surface of the cylinder by the action of centrifugal force and dried to form an endless belt-shaped intermediate product. A transfer body can be manufactured.

Examples of the additive for making the intermediate transfer member semiconductive are carbon black, metal powder, conductive polymer and the like.

<Image Forming Apparatus of the Present Invention> In the image forming apparatus of the present invention, as a first example, the flat toner image of the present invention is successively formed on the photoconductor of the present invention, and a colored toner image is formed. An image forming apparatus that transfers a toner image onto a transfer material by a pressure transfer method and fixes the image to form an image. The toner image is formed on a photoconductor so that a flat portion of the toner lies on the photoconductor. The toner image of No. 1 is a roller member or a belt member to the transfer material, to which a constant voltage of DC 300 to 3000V is applied from the back surface of the transfer material, 9.8 × 10 ² to 9.8 × 10 ^4.
It is characterized in that they are brought into contact with each other with a contact pressure of (Pa) and transferred in that state (so that the flat portion of the toner lies down).

In the image forming apparatus of the present invention, the second
As an example, a colored toner image is formed on the photoconductor of the present invention subsequent to the flat toner image of the present invention, and the toner image is transferred onto the intermediate transfer member by a pressure transfer method. Is an image forming apparatus that re-transfers the toner image of No. 1 onto a transfer material by a pressure transfer method, and fixes the image to form an image.The toner image is formed on the photoconductor so that the flat portion of the toner lies, In this state, the toner image is transferred onto the intermediate transfer member, and the toner image on the intermediate transfer member is retransferred onto the transfer material as it is.

In the pressure transfer system of the second image forming apparatus, the pressure transfer from the photosensitive member to the intermediate transfer member is performed by using a roller member or a blade member to which a constant voltage of DC 300 to 3000V is applied from the back surface of the intermediate transfer member. 5 x 9.8 x 10
^The intermediate transfer body is pressed against the transfer material at a contact pressure of ^{1 to} 5 × 9.8 × 10 ³ (Pa), and pressure transfer from the back surface of the transfer material is performed at a low voltage of DC 300 to 3000V. The applied roller member or belt member is set to 9.8 × 10 ² to 9.8.
The contact is performed with a contact pressure of × 10 ⁴ (Pa).

Embodiments of the image forming apparatus of the present invention will be specifically described below with reference to FIGS.

FIG. 3 illustrates the image forming apparatus of the present invention 1
FIG. 4 is a sectional configuration diagram showing an example image forming apparatus, FIGS. 4 and 5 are sectional configuration diagrams showing another example of a color image forming apparatus for explaining the image forming apparatus of the present invention, and FIGS. FIG. 9 is a cross-sectional configuration diagram showing still another example of the color image forming apparatus for explaining the image forming apparatus of the invention.

(Image Forming Apparatus of FIG. 3) In the image forming apparatus of FIG. 3, a plurality of sets of chargers, exposing devices (internal exposure type) and developing devices are arranged on the periphery of a cylindrical photosensitive drum, and one pass To form a superimposed toner image on the photosensitive drum,
The superposed toner images are collectively transferred onto the transfer material P which is fed from the paper feeding device at the same timing by the pressure transfer method of the present invention and fixed by the heat roller fixing device to form a color image. Here, the photosensitive drum 10 includes a transparent conductive layer on the outer periphery of a cylindrical transparent substrate formed of a transparent member such as glass or transparent acrylic resin, and an organic photosensitive layer ( (Also referred to as a photosensitive layer).

The photosensitive drum 10 is rotated clockwise by the power from a driving source (not shown) with the transparent conductive layer being grounded.

In the present invention, the light transmittance of the light-transmissive substrate of the photosensitive drum 10 does not have to be 100%, but it is preferable that the light transmittance required for image formation is 70% or more. As a material of the light-transmitting substrate, an acrylic resin, particularly a polymer of methacrylic acid methyl ester, is preferably used since it is excellent in light-transmitting property, strength, accuracy, surface property and the like. In addition, various translucent resins such as acrylic, fluorinated polyester, polycarbonate, and polyethylene terephthalate used for general optical members can be used. As the translucent conductive layer, for example, a translucent metal thin film made of indium tin oxide (ITO), tin oxide, lead oxide, indium oxide, copper iodide, Au, Ag, Ni, Al or the like is used. As a film forming method,
Vacuum deposition method, active reaction deposition method, various sputtering methods,
Various CVD methods, dip coating methods, spray coating methods and the like can be used. As the photosensitive layer, various organic photosensitive layers can be used.

A scorotron type charger 11 having a corona discharge electrode 11a and a control grid 11b, an exposure optical system 12 as an image writing means, and a developing device 13 as a developing means are prepared for the image forming process. And is arranged in the rotation direction of the photoconductor drum 10 indicated by the arrow.

The charger 11 is in a direction orthogonal to the moving direction of the photosensitive drum 10 (the direction perpendicular to the paper surface in FIG. 3).
The control grid 11b, which is attached to the photosensitive drum 10 so as to face the photosensitive drum 10 and is held at a predetermined potential with respect to the photosensitive layer of the photosensitive drum 10, and a corona discharge electrode 11a, for example, a sawtooth electrode The charging action (negative charging in the present embodiment) is performed by corona discharge having the same polarity as in (1) to apply a uniform potential to the photoconductor drum 10. Other wire electrodes or needle electrodes can be used as the corona discharge electrode 11a.

The exposure optical system 12 is a linear exposure element (not shown) in which a plurality of LEDs (light emitting diodes) as light emitting elements for image exposure light are arranged in an array parallel to the axis of the photosensitive drum 10. And a SELFOC lens (not shown) as an equal-magnification imaging element are configured as an exposure unit attached to a holder. Each exposure optical system 12 is attached to a cylindrical holder 20 as an exposure optical system holding member and housed inside the base of the photoconductor drum 10.
The exposure means is, of course, not limited to this, and F,
A linear one is used in which a plurality of light emitting elements such as L (fluorescent substance light emission), EL (electroluminescence), PL (plasma discharge) are arranged in an array.

Exposure optical system 1 as each image writing means
2 indicates the exposure position on the photosensitive drum 10 by the charger 11
Between the developing device 13 and the developing device 13, it is disposed inside the photosensitive drum 10 in a state of being provided on the upstream side in the rotation direction of the photosensitive drum 10 with respect to the developing device 13.

The exposure optical system 12 timings out an image signal obtained by image-processing the image data sent from a separate computer (not shown) and stored in the memory, and the photosensitive drum uniformly charged. Image exposure to 10,
An electrostatic latent image is formed on the photosensitive drum 10.

Each of the developing devices 13 internally has a color of yellow (Y), magenta (M), cyan (C) or black (K), a transparent toner, a light color toner of any color, or the like for the purpose of forming an image thereof. A two-component (or one-component) developer containing the combined toner is contained, and each is formed of, for example, a cylindrical non-magnetic stainless steel or aluminum material having a thickness of 0.5 to 1 mm and an outer diameter of 15 to 25 mm. It also includes a developing sleeve 13a which is a developer carrying member.

In the developing area, the developing sleeve 13a is kept in non-contact with the photoconductor drum 10 by abutting rollers (not shown) with a predetermined gap, for example, 100 to 1000 μm, and the rotation direction of the photoconductor drum 10 is kept. The developing roller is configured to rotate in the forward direction at the closest position, and at the time of development, the developing sleeve 13a has a DC voltage of the same polarity as the toner (negative polarity in this embodiment) or an AC voltage superimposed on a DC voltage. By applying a bias voltage, non-contact reversal development is performed on the exposed portion of the photosensitive drum 10. At this time, the development interval accuracy needs to be about 20 μm or less in order to prevent image unevenness.

As described above, the developing device 13 causes the electrostatic latent image on the photosensitive drum 10 formed by the charging by the charging device 11 and the image exposure by the exposure optical system 12 to be carried out in a non-contact state on the photosensitive drum 10. Reversal development is performed with toner having the same polarity as the charging polarity (in the present embodiment, the photosensitive drum is negatively charged and the toner has a negative polarity).

In the actual image formation, the photosensitive drum 10 is rotated clockwise by the start of the drive motor for driving the photosensitive drum 10 (not shown), and at the same time, the charging operation of the charger 11 causes the photosensitive drum 10 to rotate. Application of electric potential to the photoconductor drum 10 is started. After the photoconductor drum 10 is applied with an electric potential, the exposure optical system 12 starts exposure (image writing) by an image signal corresponding to the first image, and the surface of the photoconductor drum 10 is scanned by rotation to form an original image. First image (for example, transparent toner image or light color toner image)
An electrostatic latent image corresponding to is formed. This latent image is the developing device 1
3 is subjected to reversal development in a non-contact state by the photosensitive drum 1
The first toner image is formed on 0.

Next, the photosensitive drum 10 is given a potential on the toner image by the charging action of the second charger 11, and corresponds to the second image signal of the second exposure optical system 12. Exposure (image writing) is performed by the image signal to perform the second developing process, and the second toner image is formed on the first toner image by non-contact reversal development by the second developing device 13. To be done.

By the same process, if necessary, a toner image corresponding to the third image signal and a toner image corresponding to the fourth image signal are sequentially superposed and formed,
Within one rotation of the photosensitive drum 10, a superposed toner image is formed on the peripheral surface thereof.

On the other hand, the transfer paper P as the transfer material is sent out from the paper feed cassette 15 as the transfer material accommodating means by the sending-out roller (no reference numeral) and is sent by the feeding roller (no reference numeral) to the timing roller. It is transported to 16.

The transfer material P is synchronized with the toner image carried on the photosensitive drum 10 by driving the timing roller 16, and the endless belt is charged by the charging of the paper charger (not shown) as the paper charging means. It is adsorbed by the sheet-shaped conveying member 14a and fed to the transfer area. A voltage (300 to 3000 V) is applied to the transfer material P, which has been conveyed in close contact by the transfer member 14a, by a bias electrode (not shown) having a polarity opposite to that of the toner (positive polarity in this embodiment) in the transfer area, and 9.8 ×. The primary transfer roller 14 that transfers by pressing from the back surface of the transfer material P with a pressing force of 10 ^{2 to} 9.8 × 10 ⁴ (Pa).
By the action of c, the superposed toner images on the peripheral surface of the photosensitive drum 10 are collectively pressed and transferred onto the transfer material P.

The transfer material P on which the toner image is transferred is neutralized by the static eliminator 14h as a transfer material separating means, separated from the endless belt-shaped conveying member 14a, and fixed by the fixing device 17.
Be transported to.

The fixing device 17 is a fixing roller 1 as an upper roll-shaped fixing rotating member for fixing a toner image.
7a and a pressure roller 17b as a lower roll-shaped fixing member that is provided so as to face the upper fixing roller 17a. At the inner center of the fixing roller 17a, infrared rays containing visible light may be included depending on the light source. Alternatively, a halogen lamp or the like that emits heat rays such as far infrared rays is provided as the heat ray irradiation means.

The transfer material P is sandwiched by the nip portion N formed between the fixing roller 17a and the pressure contact roller 17b, and the toner image on the transfer material P is fixed by applying heat and pressure, and the transfer material P is fixed. Is sent by the discharge roller 18 and discharged to the tray above the apparatus.

The toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is cleaned by the cleaning blade provided in the cleaning device 19 as the photosensitive member cleaning means. The photoconductor drum 10 from which the residual toner has been removed is uniformly charged by the charger 11 and enters the next image forming cycle.

The above-mentioned image forming apparatus is the first and second embodiments of the present invention.
It is often used to implement the second or third invention. In that case, in order to reduce the amount of transparent toner used, the areas of the transparent toner image and the colored toner image may be exactly matched. However, it is also a good method to make the transparent toner image area larger than the colored toner image area by 1 to 3 dots.

(Color Image Forming Apparatus of FIG. 4) FIG. 4 is a cross-sectional structural view of a color image forming apparatus for explaining another embodiment of the image forming method of the present invention. Is attached.

In the color image forming apparatus shown in FIG. 4, an original placing table including an original table made of a transparent glass plate and an original cover for covering the original D placed on the original table is provided on the image forming apparatus. There is a section 111, which is below the platen and in the main body of the apparatus, a first mirror unit 112 and a second mirror unit 112
Mirror unit 113, main lens 120, color CCD
An image reading unit A including 123 and the like is provided.
The first mirror unit 112 is provided with an exposure lamp 114 and a first mirror 115 and is mounted parallel to the document table and linearly movable in the horizontal direction of the drawing, and optically scans the entire surface of the document D. The second mirror unit 113 integrally includes a second mirror 116 and a third mirror 117, and the first mirror unit 112 always maintains a predetermined optical path length.
It moves linearly in the same direction left and right at a speed of 1/2 Of course, the movement of the second mirror unit 113 is parallel to the platen as in the case of the first mirror unit 112. The image of the document D on the document table illuminated by the exposure lamp 114 passes through the first lens 115, the second mirror 116, and the third mirror 117 by the main lens 120, and the color CCD 12 is displayed.
An image is formed on top of the image. When scanning is completed, the first mirror unit 112 and the second mirror unit 113
Returns to its original position and waits for the next copy.

The image data obtained by the color CCD 123 is subjected to image processing in the image processing section, and laser writing is performed as an image signal in the image forming section E described below.

The image forming apparatus shown in FIG. 4 is a tandem type color image forming apparatus using the intermediate transfer body 14b as the image forming section E, and transparent (T), yellow ( Y), magenta (M), cyan (C), and black (K) four sets of process units 100 are provided, and each process unit 100 forms Y, M, C, and K toner images, The respective color toner images are transferred in an overlapping manner on the intermediate transfer body 14b, and the transferred color toner images are collectively transferred onto the transfer material P, fixed and discharged to the outside of the apparatus.

Five sets of process units 100T, 100
Since Y, 100M, 100C, and 100K have a common structure, one set thereof will be described as the process unit 100. The photosensitive drum 10 is obtained by providing a photosensitive layer on the outer circumference of a cylindrical conductive substrate, and the photosensitive drum 10 is indicated by an arrow in a state where the conductive substrate is grounded by power from a driving source (not shown). It is rotated counterclockwise as shown.

Reference numeral 11 denotes a scorotron type charger, which is mounted in a direction orthogonal to the moving direction of the photoconductor drum 10 so as to face and be close to the photoconductor drum 10 and to discharge the photoconductor by corona discharge having the same polarity as the toner. A uniform electric potential is applied to the drum 10.

Reference numeral 12 denotes T, Y, M, C based on the image signal.
And K is an exposure optical system for performing image exposure, for example, a scanning optical system for performing scanning in parallel with the rotation axis of the photoconductor drum 10 by a polygon mirror or the like. An electrostatic latent image is formed on the uniformly charged photosensitive drum 10 by image exposure by the exposure optical system 12.

At the periphery of the photosensitive drum 10, there is provided a developing device 13 containing a two-component developer composed of the negatively charged toner of the present invention and a magnetic carrier, and contains a magnet body to hold the developer. Then, reversal development is performed by the rotating developing sleeve 13a.

The developer is a mixture of a carrier having a ferrite core coated with an insulating resin around the core and the flat toner of the present invention, and is regulated to a layer thickness of 0.1 to 0.6 mm on the developing sleeve 13a. And transported to the development area.

The developing sleeve 13a and the photosensitive member in the developing area
The gap with the body drum 10 is larger than the layer thickness of the developer.
2 to 1.0 mm, the developing sleeve 13a and the photosensitive drum
DC voltage V between the ram 10_DCAC voltage V_ACSuperimpose
The generated AC bias voltage is applied. Toner charge
DC voltage V_DCSince it has the same polarity (negative) as AC voltage V _AC
Was given the opportunity to leave his career by
The DC voltage V_DCV with higher absolute value of electric potential_HPart of
V which has a low absolute value of electric potential_LPart of that
Toner amount corresponding to the potential difference adheres and visualizes (reverse development)
It Also, between the developing sleeve 13a and the photosensitive drum 10.
DC voltage V_DCOnly may be applied. The development is
Touch development is also acceptable. This toner image is transferred
Intermediate transfer member having the surface roughness Ra 'of the present invention
On 14b, preferably 5 × 9.8 × 10¹~ 2x9.
8 x 10³(Pa) Transferred by pressing force. After the transfer
Transfer residual toner remaining on the drum is
Cleaning is performed by the cleaning device 19 equipped with a card.
Be done.

The intermediate transfer member 14b in which the five-color process units 100T, 100Y, M, C, and K composed of T, Y, M, C, and K face each other in parallel is preferably a belt-shaped member having the above-mentioned characteristics. The drive roller 14d, the driven roller 14e, the tension roller 14k, and the backup roller 14j are stretched by being circumscribed around the drive roller 14d, and the drive roller 14d is rotated by the drive of a drive motor (not shown) during image formation. At the transfer position, the intermediate transfer body 14b is pressed against the photosensitive drum 10 by the primary transfer roller 14c and rotated in the direction shown by the arrow in the figure. The primary transfer roller 14c, which is a transfer unit for each color, is used for the intermediate transfer member 1.
4b is provided so as to face the photoconductor drums 10 for each color, and a transfer area for each color is formed between the intermediate transfer body 14b and the photoconductor drums 10 for each color. A DC voltage having a polarity opposite to that of the toner (plus polarity in the present embodiment) is applied to the primary transfer roller 14c for each color, and a transfer electric field is formed in the transfer area, so that each color on the photoconductor drum 10 is transferred. The toner image is transferred onto the intermediate transfer body 14b.

When the image recording is started, the photosensitive drum 10 of the process unit 100T is rotated in the direction shown by the arrow by the start of the photosensitive member driving motor (not shown), and at the same time, the charging action of the T scorotron charger 11 causes the T Application of electric potential to the photoconductor drum 10 is started.

After the potential is applied to the T photoconductor drum 10, image writing is started by the electric signal output from the control unit by the T exposure optical system 12, and the control unit is formed on the surface of the T photoconductor drum 10. An electrostatic latent image corresponding to the output image from is formed.

The latent image of T is subjected to reversal development in a non-contact or contact state by the developing unit 13 for T toner, and a T toner image is formed according to the rotation of the photosensitive drum 10 of T.

The T toner image formed on the T photoconductor drum 10 which is the image forming body by the above image forming process is transferred onto the intermediate transfer body 14b by the primary transfer roller 14c in the T transfer area. It

The photoconductor drum 10 of the process unit 100Y is rotated in the direction indicated by the arrow in the figure slightly after the operation of the T process unit 100T, and at the same time, the Y photoconductor drum is charged by the Y charger 11. Application of electric potential to 10 is started.

After the potential is applied to the Y photoconductor drum 10, the Y exposure optical system 12 starts the image writing by the electric signal corresponding to the Y image data in synchronization with the T toner image. An electrostatic latent image corresponding to the Y image of the original image is formed on the surface of the photosensitive drum 10.

The latent image of Y is subjected to reversal development in a non-contact or contact state by the Y developing device 13 to form a Y toner image in accordance with the rotation of the Y photosensitive drum 10. The Y toner image formed on the Y photoconductor drum 10 which is the image forming body by the above image forming process is transferred onto the T toner image of the intermediate transfer body 14b by the primary transfer roller 14c in the Y transfer area. Transcribed.

Next, the intermediate transfer body 14b is synchronized with the toner images of T and Y, and M, C corresponding to the image data of M and C formed on the photosensitive drums 10 of M and C by the process unit 100M. The C toner images are formed by the primary transfer rollers 14c in the M and C transfer areas so that the M and C toner images are superposed on the T and Y toner images.

By a similar process, the toner images of T, Y, M, and C are synchronized with each other, and are formed on the photosensitive drum 10 of K by the process unit 100K.
The K toner image using the K toner corresponding to the K image data is superposed on the T, Y, M, and C toner images by the primary transfer roller 14c in the K transfer area. T, Y, M, formed on the intermediate transfer body 14b.
A superimposed color toner image of C and K is formed.

The transfer residual toner remaining on the peripheral surface of the photosensitive drum 10 for each color after the transfer is cleaned by the cleaning device 19 which is a cleaning means for the image forming body for each color.

In synchronism with the formation of the superimposed color toner images on the intermediate transfer member 14b, the transfer material P is transferred to the second transfer material P from the paper feed cassette 15 which is the transfer material storage means and the timing roller 16 which is the transfer material feeding means. The superposed color toner image on the intermediate transfer member 14b is transferred onto the transfer material P by the secondary transfer roller 14g which is conveyed to the transfer area of the secondary transfer roller 14g which is a transfer unit and to which a DC voltage having a polarity opposite to that of the toner is applied. It is transcribed all at once on top. On the transfer material P, T, Y,
The M, C, and K color toner images are present.

The transfer material P on which the color toner image has been transferred is
The toner image on the transfer material P is fixed by being conveyed to the fixing device 17 and subjected to heat and pressure between the fixing roller 17a and the pressure bonding roller 17b, and then the discharge roller 18
And then discharged to the tray above the device.

The transfer residual toner remaining on the peripheral surface of the intermediate transfer body 14b after the transfer is a cleaning device 19 which is a cleaning means for the intermediate transfer body 14b which is provided so as to face the driven roller 14e with the intermediate transfer body 14b interposed therebetween. To be cleaned.

The intermediate transfer member 14b in which five sets of process units 100 of T, Y, M, C and K face each other in parallel is a semiconductive endless belt having the above-mentioned characteristics, and includes a driving roller 14d, a driven roller 14e, and The tension roller 14k and the backup roller 14j are wound around and stretched. The drive roller 14d is rotated by the drive of a drive motor (not shown) during image formation, and the primary transfer roller 14c exposes each color at a transfer position for each color. The intermediate transfer body 14b is pressed against the body drum 10, and the intermediate transfer body 14b is rotated in the direction shown by the arrow in the figure. The pressing force during the primary transfer (transfer from the photosensitive member to the intermediate transfer member) is 5 × 9.8 × 10 ^1.
˜2 × 9.8 × 10 ³ (Pa) The pressing force during transfer from the transfer body to the transfer material is 9.8 × 10 ^{2 to} 9.8 × 10 ⁴ (Pa).
Is preferred.

The fixing method used in the present invention is a so-called contact heating method. In particular, the contact heating method may be a heat pressure fixing method, a heat roll fixing method, or a pressure contact heat fixing method in which fixing is performed by a rotating pressure member containing a fixedly arranged heating body.

In the heat roll fixing system, an elastic layer made of silicone rubber or the like having a surface coated with tetrafluoroethylene, polytetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer or the like has a heat source inside in many cases. It is composed of an upper roller formed on the outer circumference of a metal cylinder made of iron or aluminum, and a lower roller having an elastic layer made of silicone rubber or the like formed on the outer circumference of the metal cylinder. As a heat source, a linear heater is used, and the surface temperature of the upper roller is 120 to 20.
A typical example is heating to about 0 ° C. In the fixing unit, pressure is applied between the upper roller and the lower roller to deform the upper and lower rollers to form a so-called nip. The nip width is 1 to 10 mm, preferably 1.5 to 7 mm.
The fixing linear velocity is preferably 40 mm / sec to 600 mm / sec. If the nip is too narrow, heat cannot be uniformly applied to the toner, resulting in uneven fixing.
On the other hand, when the nip width is too wide, the melting of the resin is promoted, causing a problem of excessive fixing offset. A fixing cleaning or oil coating mechanism may be added for use. As this method, a method of supplying silicone oil to the roller after fixing or a method of cleaning with a pad, roller or web impregnated with silicone oil can be used.

(Example of Color Image Forming Apparatus of FIG. 5)
4 is a cross-sectional configuration diagram of a color image forming apparatus for explaining still another embodiment of the image forming method of the present invention, and the same contents as those in FIG. 4 are denoted by the same reference numerals.

The color image forming apparatus shown in FIG. 5 is similar to the color image forming apparatus shown in FIG. 4, but in FIG. 4, an endless belt-shaped intermediate transfer member 14b is used.
On the other hand, the color image is formed by superposing each color toner image on 4b to form a color toner image, and the color toner image is transferred onto the transfer material P and fixed to form a color image. The difference is that a color toner image is formed by superimposing the toner images of respective colors directly on the transfer material P conveyed by the endless belt-shaped conveying member 14a, and the color toner image is fixed to form a color image. is doing. The endless belt-shaped conveying member 14a in FIG. 5 is not particularly limited as long as it is a member that can easily convey the transfer material.
A rubber or plastic endless belt-shaped member having a thickness of 5 to 2 mm is used. Reference numeral 150 in FIG. 5 is an electrode for attaching the transfer material to the endless belt-shaped transport member 14a.

(Example of Color Image Forming Apparatus of FIGS. 6 and 7) FIG. 6 shows an example of a color image forming apparatus different from the above. This is provided with a plurality of image forming means on the same photosensitive drum. In FIG. 6, except for the process unit 100T for forming a transparent toner image, two image forming means, that is, chargers 11 (L) and 11 (H), and exposure optical systems 12 (L) and 12 ( H), developing unit 13 (L) and 1
It has 3 (H).

By doing so, for example, toner images of Y, M, C, and K can be formed by using two kinds of toner of the same color, dark and light, and a color image with high gradation can be obtained. I can. It should be noted that the above (L) and (H) refer to light color toner and dark color toner, respectively, and the color image forming apparatus in FIG. 6 is, for example, the third invention or the fourth invention of the present invention. The image forming apparatus can be preferably used in the invention.

Further, the color image forming apparatus of FIG. 7 has a similar form to the above, but does not have an intermediate transfer member, and directly transfers a toner image of each color onto the transfer material P conveyed by the endless belt-shaped conveying member 14a. It is an example of an image forming apparatus of a type that transfers and forms a superimposed color toner image.

The numbers assigned to these members are the same as those used in FIGS. A detailed description of the process of forming a superimposed color image is omitted. However, since it is almost the same as the case of FIGS. 3 to 5 except that both the light color toner image and the dark color toner image of the same color are formed on the same photosensitive drum 10, it can be easily understood.

[0168]

EXAMPLES The present invention will be specifically described with reference to Examples.
Embodiments of the present invention are not limited to these.

[1] Example 1 (Example of the First Invention) << Toner Production >> (Transparent Toner) A solution containing 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 L of ion-exchanged water was used as an anionic surfactant. Solution A ".

0.014 kg of nonylphenol polyethylene oxide adduct and 4.0 L of deionized water
Was used as "Nonionic surfactant solution B".
223.8 g of potassium persulfate, 12.0 L of ion-exchanged water
The solution dissolved in was designated as "initiator solution C".

In a 100 L glass-lined (GL) reaction kettle equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device, W
AX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration = 29.9%) 3.41 kg, "anionic surfactant solution A" whole amount and "nonionic surfactant solution B""
The total amount was added and stirring was started. Next, deionized water 4
4.0 L was added.

Next, heating was started, and when the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Then, while controlling the liquid temperature to 75 ± 1 ° C, styrene 1
2.1 kg, n-butyl acrylate 2.88 kg, methacrylic acid 1.04 kg and t-dodecyl mercaptan 5
48 g of premixed solution was added dropwise. After completion of the dropping, the liquid temperature was raised to 80 ± 1 ° C. and the mixture was heated and stirred for 6 hours to complete the polymerization. Then, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and the mixture was filtered with a pole filter to obtain “latex 1-A”.

The resin particles in "latex 1-A" had a glass transition point of 57 ° C., a softening point of 121 ° C., a weight average molecular weight of 127,000 and a weight average particle diameter of 120 nm.

A solution prepared by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 L of ion-exchanged pure water was designated as "anionic surfactant solution D". Further, a solution prepared by dissolving 0.014 kg of a 10-mol addition product of nonylphenol polyethylene oxide in 4.0 L of ion-exchanged water was designated as "nonionic surfactant solution E".

Potassium persulfate (manufactured by Kanto Chemical Co., Inc.) 200.
A solution prepared by dissolving 7 g in 12.0 L of ion-exchanged water was designated as "initiator solution F".

In a 100 L GL reaction kettle equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a comb-shaped baffle, a WAX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter = 120 nm, solid content concentration = 29) (1.9%), 3.41 kg, the total amount of "anionic surfactant solution D" and the total amount of "nonionic surfactant solution E" were added, and stirring was started. Next, ion-exchanged water 44.0
L was added. Heating was started, and when the liquid temperature reached 70 ° C., “initiator solution F” was added. Next, 11.0 kg of styrene and 4.00 k of n-butyl acrylate
g, 1.04 kg of methacrylic acid and 9.02 g of t-dodecyl mercaptan were pre-mixed and added dropwise. After completion of the dropping, the liquid temperature was controlled at 72 ° C. ± 2 ° C. and heating and stirring were performed for 6 hours, and then the liquid temperature was raised to 80 ° C. ± 2 ° C. and heating and stirring were performed for 12 hours to complete the polymerization. Next, the liquid temperature is 40 ° C.
The mixture was cooled to below, stirring was stopped, and the mixture was filtered through a pole filter to obtain "latex 1-B".

The resin particles in "latex 1-B" had a glass transition point of 58 ° C., a softening point of 132 ° C., a weight average molecular weight of 245,000 and a weight average particle diameter of 110 nm.

5.36 kg of sodium chloride as a salting-out agent
Was dissolved in 20.0 L of ion-exchanged water to be referred to as "sodium chloride solution G".

100 L of S equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a particle size and shape monitoring device.
Into a US reactor, 20.0 kg of "latex 1-A" prepared above, 5.2 kg of "latex 1-B" and 20.0 kg of ion-exchanged water were placed and stirred.

After standing for 10 minutes, the temperature rise is started, the temperature is raised to 85 ° C. in 60 minutes, and the mixture is heated and stirred at 85 ± 2 ° C. to grow the grain size while salting out / fusing, and fusing. When the average particle size of the transparent particles reached 3 μm, “sodium chloride solution G” was added to stop the particle size growth. This liquid was designated as "fusion-bonded transparent particle dispersion liquid 1".

Similarly, a solution in which the average particle size of the fused transparent particles was grown to 6.5 μm and 8.5 μm was prepared, and these were prepared as “fusion transparent particle dispersion 2” and “fusion transparent particle dispersion liquid 2”. Transparent particle dispersion 3 ".

Next, 5 equipped with a temperature sensor and a cooling pipe
In the L reaction vessel, the above-mentioned “fusion-bonded transparent particle dispersion liquid 1”
"Fusionable transparent particle dispersion liquid 3" (5.0 kg) was added, and the liquid temperature was 9
While observing the change in shape of the fused particles at 2 ± 2 ° C., heating and stirring were performed until the average value of the shape factor was 0.98 or more, and the fused particles were spheroidized. These are “spherical transparent particle dispersion 1” (average particle size 3 μm), “spherical transparent particle dispersion 2” (average particle size 6.5 μm) and “spherical transparent particle dispersion 3” (average particle size 8.5 μm) And

Next, 1 kg of "spherical transparent particle dispersion liquid 1" to "spherical transparent particle dispersion liquid 3" and 1 kg of glass beads having an average particle size of 0.6 mm were respectively sand grinder (medium type disperser; inner diameter 200 mm, stirring). Disk diameter 18
0 mm) at 85 ± 2 ° C. and 500 rpm.
A flattening treatment was carried out by continuously stirring for 5 to 5 hours. After the treatment for a predetermined time, it is cooled to 40 ° C or lower, and after stirring is stopped,
After removing the glass beads through a 200-mesh sieve, wet cake-like flat transparent particles were collected by using a nutsche filter. Washing with ion-exchanged water and filtration 3
After repeating, the wet cake-shaped flat transparent particles were pre-dried at a suction temperature of 50 ° C. using a flash jet dryer, and further dried at a temperature of 55 ° C. using a fluidized bed dryer to obtain “flat transparent particles”. Was manufactured.

Hydrophobic silica fine particles were externally added to and mixed with the obtained "flat transparent particles" in a Henschel mixer to produce "flat transparent toners 1 to 12".

(Toner Shape, etc.) Flat transparent toners 1-1
Table 1 shows the shape of No. 2, the particle size (d, t, d / t), and the amount of the external additive treated.

The equivalent circle diameter d and the thickness t when viewed from the direction in which the projected area of the toner particles in the table is the maximum are such that the toner particles are uniformly dispersed and adhered on the smooth surface, and the toner particles 500
Each piece was magnified 500 times from the upper surface with a laser microscope to measure the equivalent circle diameter and the maximum height, and the arithmetic mean value was calculated.

[0187]

[Table 1]

The amount of the external additive in the table is the amount (% by mass) added to the toner, and the amount of the external additive per unit area of the toner was set to be the same.

(Spherical black toner) 0.90 kg of sodium n-dodecylsulfate and 10.0 L of pure water were put and stirred and dissolved. To this solution, 1.20 kg of Regal 330R (Carbon Black manufactured by Cabot Corporation) was gradually added, and 1
After stirring well for a long time, a sand grinder (medium type disperser) was used for continuous dispersion for 20 hours. This was designated as "colorant dispersion liquid 1".

A solution containing 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 L of ion-exchanged water was designated as "anionic surfactant solution A".

0.014 kg of nonylphenol polyethylene oxide adduct 0.014 kg and ion-exchanged water 4.0 L
Was used as "Nonionic surfactant solution B".
223.8 g of potassium persulfate, 12.0 L of ion-exchanged water
The solution dissolved in was designated as "initiator solution C".

In a 100 L glass-lined (GL) reaction kettle equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device, W
AX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration = 29.9%) 3.41 kg, "anionic surfactant solution A" whole amount and "nonionic surfactant solution B""
The total amount was added and stirring was started. Next, deionized water 4
4.0 L was added.

Next, heating was started, and when the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Then, while controlling the liquid temperature to 75 ± 1 ° C, styrene 1
2.1 kg, n-butyl acrylate 2.88 kg, methacrylic acid 1.04 kg and t-dodecyl mercaptan 5
48 g of premixed solution was added dropwise. After completion of the dropping, the liquid temperature was raised to 80 ± 1 ° C. and the mixture was heated and stirred for 6 hours to complete the polymerization. Then, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and the mixture was filtered with a pole filter to obtain “latex 1-A”.

The resin particles in "latex 1-A" had a glass transition point of 57 ° C., a softening point of 121 ° C., a weight average molecular weight of 127,000 and a weight average particle diameter of 120 nm.

Further, a solution prepared by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 L of ion-exchanged pure water was designated as "anionic surfactant solution D". Further, a solution prepared by dissolving 0.014 kg of a 10-mol addition product of nonylphenol polyethylene oxide in 4.0 L of ion-exchanged water was designated as "nonionic surfactant solution E".

Potassium persulfate (manufactured by Kanto Chemical Co., Inc.) 200.
A solution prepared by dissolving 7 g in 12.0 L of ion-exchanged water was designated as "initiator solution F".

In a 100 L GL reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle, a WAX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter = 120 nm, solid content concentration = 29) (1.9%), 3.41 kg, the total amount of "anionic surfactant solution D" and the total amount of "nonionic surfactant solution E" were added, and stirring was started. Next, ion-exchanged water 44.0
L was added. Heating was started, and when the liquid temperature reached 70 ° C., “initiator solution F” was added. Next, 11.0 kg of styrene and 4.00 k of n-butyl acrylate
g, 1.04 kg of methacrylic acid and 9.02 g of t-dodecyl mercaptan were pre-mixed and added dropwise. After completion of the dropping, the liquid temperature was controlled at 72 ° C. ± 2 ° C. and heating and stirring were performed for 6 hours, and then the liquid temperature was raised to 80 ° C. ± 2 ° C. and heating and stirring were performed for 12 hours to complete the polymerization. Next, the liquid temperature is 40 ° C.
The mixture was cooled to below, stirring was stopped, and the mixture was filtered through a pole filter to obtain "latex 1-B".

The resin particles in "latex 1-B" had a glass transition point of 58 ° C., a softening point of 132 ° C., a weight average molecular weight of 245,000 and a weight average particle diameter of 110 nm.

5.36 kg of sodium chloride as a salting-out agent
Was dissolved in 20.0 L of ion-exchanged water to be referred to as "sodium chloride solution G".

100 L of S equipped with a temperature sensor, cooling pipe, nitrogen introducing device, particle size and shape monitoring device
In a US reactor, 20.0 kg of the "latex 1-A" prepared above, 5.2 kg of "latex 1-B", 0.4 kg of "colorant dispersion 1" and 20.
0 kg was added and stirred.

After standing for 10 minutes, the temperature rise was started, the temperature was raised to 85 ° C. in 60 minutes, and the mixture was heated and stirred at 85 ± 2 ° C. to grow the grain size while salting out / fusing and fusing. When the average particle size of the particles reached 6.5 μm, “sodium chloride solution G” was added to stop the particle size growth. This liquid was designated as "fusion black particle dispersion liquid".

Next, 5 equipped with a temperature sensor and a cooling pipe
In the L reactor, 5.0 k of the above "fusion black particle dispersion liquid"
g, and while observing the shape change of the fused particles at a liquid temperature of 92 ± 2 ° C., the mixture is heated and stirred until the average value of the shape factor becomes 0.98 or more, and the fused particles are spheroidized. went. These are “spherical black particle dispersion” (average particle size 6.5μ
m). The equivalent circle diameter of this product was 6.6 μm, and the thickness was 6.4 μm.

Wet cake-like black particles were collected by filtration using a Nutsche. After washing with ion-exchanged water and filtration three times, the black particles were pre-dried at a suction temperature of 50 ° C using a flash jet dryer, and further dried at a temperature of 55 ° C using a fluidized bed drier. Spherical black particles "were manufactured.

To the obtained "spherical black particles", 1.5% by mass of hydrophobic silica fine particles was externally added and mixed with a Henschel mixer to produce "spherical black toner".

(Preparation of Developer) In the case of producing a developer of spherical toner of each color and a 65 μm ferrite carrier coated with a silicone resin, the addition amount of the toner to the carrier was set to 8% by mass.

As a result, the "transparent developer" for evaluation,
A "black developer" was prepared. (Production of Internal Exposure Type Photosensitive Drum) An internal exposure type photosensitive drum of an organic photoconductor having the following constitution was incorporated in the image forming apparatus shown in FIG. The conductive support is a cylindrical transparent substrate made of polymethylmethacrylate and provided with an indium tin alloy (ITO) layer of 0.5 μm, and the following undercoat layer (intermediate layer) and charge generation layer are provided on the substrate. (CG
L), a lower layer charge transport layer (lower layer CTL), and an upper layer charge transport layer (upper layer CTL).

<< Undercoat Layer >> Titanium chelate compound (TC-750: manufactured by Matsumoto Pharmaceutical Co., Ltd.) 30 g Silane coupling agent (KBM-503: manufactured by Shin-Etsu Chemical Co., Ltd.) 17 g 2-propanol 150 ml Cylindrical using the above coating liquid An undercoat layer 6 having a thickness of 0.5 μm was formed on the substrate.

<< CGL >> Y-type titanyl phthalocyanine (maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-rays is 27.3 degrees at 2θ) 60 g Silicone-modified butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co., Ltd.) 700 g 2-butanone 2000 ml were mixed and dispersed using a sand mill for 10 hours.
A coating liquid was prepared. This coating solution was applied on the undercoat layer by a dip coating method to form a CGL having a dry film thickness of 0.2 μm.

<< Lower Layer CTL >> CTM [3N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine] 225 g polycarbonate (viscosity average molecular weight 30,000) 300 g dichloromethane 2000 ml The mixture was dissolved to prepare a coating liquid for CTL. This coating solution was applied onto the CGL by a dip coating method to give a dry film thickness of 1
A 5 μm lower layer CTL was formed.

<< Upper Layer CTL >> CTM [N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine] 100 g Polycarbonate (viscosity average molecular weight 30,000) 300 g Dichloromethane 2000 ml Volume 25 g of silica fine particles having an average particle size of 0.1 μm were mixed and dissolved to prepare a coating liquid for the upper layer CTL. This coating solution was applied onto the lower layer CTL by a dip coating method to form an upper layer CTL having a dry film thickness of 5 μm, and an internal exposure type photosensitive drum was obtained.

(Performance Evaluation Test) Each experiment No. was set in the most upstream developing device of the image forming apparatus of FIG. A transparent developer using flat transparent toners 1 to 12 was loaded for each of them, and then a black developer was loaded in the upstream developing device to form an image in the same area on both sides to form a superposed image. . A comprehensive judgment was made by combining the transfer rate from the formed body onto the transfer material and the effect of reducing the transparent toner consumption amount. At the same time, the flat transparent toner 6
Was used to evaluate the characteristics when the amount of the transparent toner deposited was varied, in the same manner as above.

The evaluation method and criteria were as follows. 1) Transfer rate The amount shown in Table 2 as a transparent toner adhesion amount was developed and adhered on the photoconductor, and then spherical black toner was developed and adhered to the maximum image density (0.5 mg / cm ² ). This was transferred onto a transfer material (plain paper) and calculated by the following.

Transfer rate = {Amount of transferred toner (mg / c
m ² ) /0.5 mg / cm ² } × 100 ○: 92% or more, Δ: less than 92% 80% or more, ×: 80
%) 2) Effect of reducing the amount of transparent toner used ○: 30% or more than spherical transparent toner, Δ: less than 30%, but somewhat, ×: equivalent to spherical transparent toner, XX: no effect compared to spherical transparent toner Is shown in Table 2 below, and it can be seen that only those within the present invention show good results in a comprehensive view.

[0214]

[Table 2]

[2] Example 2 (Example of the Second Invention) The flat transparent toner and the spherical black toner used in Example 1 were tested in the same manner and the performance was evaluated.

However, the second developer from the upstream side of the image forming apparatus of FIG. Flat transparent toner 1 to 12 for each
Was loaded with a transparent developer. Further, the transfer section of the image forming apparatus was used after being modified so that it was once transferred to a belt-shaped intermediate transfer member made of polyimide and then transferred to a transfer material of plain paper.

The evaluation method and criteria were as follows. 1) It was visually judged by looking at the image after fixing the glossiness.

[0218] ○: good, △: effective but slightly insufficient, ×: no effect 2) Reduction effect of transparent toner usage The evaluation was performed in the same manner as in Example 1.

The results are shown in Table 3 below, and it can be seen that only those within the present invention generally show good results.

[0220]

[Table 3]

[3] Example 3 (Example of the third invention) <Toner manufacturing> Manufacture of flat light toner of each color The flat transparent toner was manufactured as follows.

After the flat light black toners "latex 1-A" and "latex 1-B" were prepared, "fusion transparent particle dispersion 1", "fusion transparent particle dispersion 2", and "fusion transparent particle dispersion 2" in Example 1 were prepared. The case of producing the fused transparent particle dispersion 3 "was changed as follows. 20.0 kg of "latex 1-A" prepared above and "latex 1" were placed in a 100 L SUS reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a particle size and shape monitoring device.
-B "was added to 5.2 kg and ion-exchanged water 20.0 kg, and 0.1 kg of" colorant dispersion liquid 1 "using carbon black was added and stirred.

Flat light yellow toner, flat light magenta toner Flat light cyan toner was prepared in the same manner as above except that the colorant was changed to 1/4 amount of spherical dark toner described later.

(Toner shape, etc.) Flat transparent toner 1-1
The shape and particle size (d, t, d / t) of No. 2 were measured in the same manner as in Example 1, but substantially the same result as that of the flat transparent toner was obtained. Therefore, the external additive treatment amount was also added in the same manner as in Table 1. The same applies to the flat light-colored toners of yellow, magenta, and cyan.

Manufacture of Spherical Dark Color Toner of Each Color A colorant was added in the following manner according to the spherical black toner.

(Spherical Yellow Toner) In the manufacture of spherical black toner, a colorant is C.I. instead of carbon black.
I. "Spherical yellow toner" was manufactured in the same manner except that 1.05 kg of Pigment Yellow 17 was used.

(Spherical Magenta Toner) In the production of spherical black toner, a colorant was used instead of carbon black.
I. "Spherical magenta toner" was manufactured in the same manner except that 1.2 kg of Pigment Red 122 was used.

(Spherical Cyan Toner) In the manufacture of spherical black toner, a colorant is C.I. instead of carbon black. I.
Pigment Blue 15: 3 was used in the same manner except that 0.6 kg of "Blue spherical toner" was manufactured.

(Toner shape, etc.) The measured values were substantially the same as those of the spherical black toner.

The color image forming apparatus of FIG. 6 was used, and the shade developers of the respective colors were used in combination. Table 4 shows the results of determining the transfer rate and the image gradation at that time by the following methods. The results were the same for all the dark and light black developers, cyan developers, magenta developers, and yellow developers, and therefore Table 4 below shows the results for the black developers.

Evaluation of the transfer rate and the effect of reducing the amount of transparent toner used was carried out in the same manner as in Example 1.

Regarding the image gradation property, the gradation property of the low density portion is visually judged, and ◯: good, Δ: there is a problem in a particularly delicate gradation image, ×: there is no effect of using the dark and light toner, Was written as.

[0233]

[Table 4]

As shown in Table 4, it can be seen that all the properties within the present invention are good, but those outside the present invention have problems with any of the properties.

[4] Example 4 (Example of Fourth Invention) The flat transparent toner and the spherical dark color toner produced in Examples 1 and 3 were loaded into the image forming apparatus shown in FIG. The characteristics were evaluated.

1) Transfer Rate from Intermediate Transfer Body to Transfer Material (Plain Paper) The transfer rate from the image forming body to the transfer material is represented by the following.

◯: 92% or more, Δ: less than 92%, 80% or more, x: less than 80% 2) Effect of reducing the amount of transparent toner used.

[0238]

[Table 5]

As is clear from Table 5, all of the materials within the present invention show good characteristics, while those outside the present invention have problems in any of the characteristics.

[0240]

According to the present invention, it is possible to provide a technique in which a transparent toner or a light-colored toner is used and the effects such as improvement of glossiness, transferability, and gradation are obtained, and the consumption of toner is reduced. I can.

[Brief description of drawings]

FIG. 1 is a plan view and a side view of a flat toner.

FIG. 2 is a diagram showing an example of the relationship between the flattening processing time and the shape of flattened toner.

FIG. 3 is a sectional configuration diagram of an image forming apparatus according to the present invention.

FIG. 4 is a sectional configuration diagram of an example of a color image forming apparatus according to the present invention.

FIG. 5 is a cross-sectional configuration diagram of a color image forming apparatus according to an example of the present invention.

FIG. 6 is a cross-sectional configuration diagram of a color image forming apparatus according to an example of the present invention.

FIG. 7 is a cross-sectional configuration diagram of a color image forming apparatus according to an example of the present invention.

[Explanation of symbols]

10 Photoconductor Drum 11 Charging Device 12 Exposure Optical System 13 Developing Device 14a Conveying Member 14b Intermediate Transfer Body 14c Primary Transfer Roller 14g Secondary Transfer Roller 16 Timing Roller 17 Fixing Device 19 Cleaning Device P Transfer Material (Transfer Paper) 100T, 100Y , 100M, 100C, 100K
Transparent, yellow, magenta, cyan, black process units

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H005 AA15 AA21                 2H030 AB02 AD01 BB02 BB22 BB42                       BB43

Claims (16)

[Claims] 1. A transparent toner image and a color toner image are superposed in this order on an image forming body, and then the transparent toner image and the color toner image are collectively transferred onto a transfer material or an intermediate transfer body. In the image forming apparatus, the transparent toner forming the transparent toner image has a circle equivalent diameter Dt of 5 to 15 (μm) and a thickness Ht of 1 when viewed from the direction in which the projected area is maximum.
-4 (μm), the flatness Ft expressed by Dt / Ht is 2
The flat toner of No. 6 is used, and the adhesion amount M / At (mg / cm ² ) of the transparent toner and the density of the transparent toner is ρt (g / cm ³ ), the image forming apparatus satisfies the following relationship. 0.02 × ρt × Ht ≦ M / At ≦ 0.06 × ρt × H
t 2. A circle-equivalent diameter D as seen from the direction in which the projected area is maximum, as the colored toner forming the colored toner image.
c is 6 to 15 (μm), thickness Hc is 5 to 11 (μm),
Using a toner having a flatness Fc represented by Dc / Hc of 2 or less, the maximum adhesion amount M / Ac _max (mg / cm ² ) of the color toner formed on the image forming body, The image forming apparatus according to claim 1, wherein the following relations are satisfied, where ρc (g / cm ³ ) is the density and N is the number of colored toners when a plurality of colored toners are superposed. 0.06 × ρc × Hc × N ≦ M / Ac _max ≦ 0.12 ×
ρc × Hc × N 3. The image forming apparatus according to claim 1, wherein a circle equivalent diameter Dt of the transparent toner and a circle equivalent diameter Dc of the colored toner satisfy the following relationship. Dc <Dt 4. The image forming apparatus according to claim 1, wherein the thickness Ht of the transparent toner and the thickness Hc of the colored toner satisfy the following relationship. Ht <Hc 5. A color toner image and a transparent toner image are superposed in this order on an image forming body, and then the color toner image and the transparent toner image are collectively transferred onto a transfer material or an intermediate transfer body. In the image forming apparatus, the transparent toner forming the transparent toner image has a circle equivalent diameter Dt of 5 to 15 (μm) and a thickness Ht of 1 when viewed from the direction in which the projected area is maximum.
-4 (μm), the flatness Ft expressed by Dt / Ht is 2
The flat toner of No. 6 is used, and the adhesion amount M / At (mg / cm ² ) of the transparent toner and the density of the transparent toner is ρt (g / cm ³ ), the image forming apparatus satisfies the following relationship. 0.02 × ρt × Ht ≦ M / At ≦ 0.06 × ρt × H
t 6. A circle-equivalent diameter D as seen from the direction in which the projected area is maximum, as the colored toner forming the colored toner image.
c is 6 to 15 (μm), thickness Hc is 5 to 11 (μm),
Using a toner having a flatness Fc represented by Dc / Hc of 2 or less, the maximum value M / Ac _max (mg / cm ² ) of the adhesion amount of the color toner formed on the image forming body, The image forming apparatus according to claim 5, wherein the following relationship is satisfied, where the density is ρc (g / cm ³ ), and the number of color toners when a plurality of color toners are superposed is N. 0.06 × ρc × Hc × N ≦ M / Ac _max ≦ 0.12 ×
ρc × Hc × N 7. The image forming apparatus according to claim 5, wherein a circle equivalent diameter Dt of the transparent toner and a circle equivalent diameter Dc of the colored toner satisfy the following relationship. Dc <Dt 8. The image forming apparatus according to claim 5, wherein the thickness Ht of the transparent toner and the thickness Hc of the colored toner satisfy the following relationship. Ht <Hc 9. A light-colored toner image and a dark-colored toner image of similar colors are formed in this order on the image forming body in this order, and then the light-colored toner image and the dark-colored toner image are collectively formed on the transfer material or in the intermediate. In an image forming apparatus for transferring onto a transfer body, the equivalent circle diameter Dl is 5 to 15 (μm) and the thickness Hl is 1 to 4 as the light color toner forming the light color toner image when viewed from the direction in which the projected area is maximum. (Μm), flatness F expressed by Dl / Hl
Using a flat toner having l of 2 to 6, the adhesion amount M / Al (mg / cm ² ) of the light-color toner and the density of the light-color toner in the area where the both toner images are formed in an overlapping manner on the image forming body. An image forming apparatus characterized by satisfying the following relation when ρl (g / cm ³ ). 0.02 × ρl × Hl ≦ M / Al ≦ 0.06 × ρl × H
l 10. The dark color toner forming the dark color toner image has a circle equivalent diameter Dd of 6 to 15 (μm) and a thickness Hd of 5 to 11 (μ) as viewed from the direction in which the projected area is maximum.
m), a toner having a flatness Fd represented by Dd / Hd of 2 or less is used, and the maximum value M / Ad _max (mg / cm ² ) of the adhered amount of the colored toner formed on the image forming body is The image forming apparatus according to claim 9, wherein the following relationship is satisfied when the density of the color toner is ρd (g / cm ³ ). 0.06 × ρd × Hd ≦ M / Ad _max ≦ 0.12 × ρd
× Hd 11. The image forming apparatus according to claim 9, wherein a circle equivalent diameter Dl of the light color toner and a circle equivalent diameter Dd of the dark color toner satisfy the following relationship. Dd <Dl 12. The image forming apparatus according to claim 9, wherein a thickness Hl of the light color toner and a thickness Hd of the dark color toner satisfy the following relationship. Hl <Hd 13. A plurality of color toner images and a transparent toner image are formed on an image forming body, and then the transparent toner images are transferred to an intermediate transfer body so as to be a lower layer, and then collectively transferred onto a transfer material. In an image forming apparatus for transfer, as a transparent toner forming the transparent toner image, a circle equivalent diameter Dt viewed from a direction in which a projected area is maximum is 5 to 15 (μm) and a thickness Ht is 1 to 1.
4 (μm), the flatness Ft represented by Dt / Ht is 2 to 6
And the amount of the transparent toner adhered in the region formed by superimposing the toner on the intermediate transfer member M / A.
t (mg / cm ² ), the density of the transparent toner is ρt (g / c
m ³ ), an image forming apparatus satisfying the following relationship. 0.02 × ρt × Ht ≦ M / At ≦ 0.06 × ρt × H
t 14. The color toner forming the color toner image has a circle equivalent diameter Dc of 6 to 15 (μm) and a thickness Hc of 5 to 11 (μ) as viewed from the direction in which the projected area is maximum.
The image forming apparatus according to claim 13, wherein a toner having a flatness Fc represented by m) and Dc / Hc of 2 or less is used. 15. The image forming apparatus according to claim 13, wherein the circle equivalent diameter Dt of the transparent toner and the circle equivalent diameter Dc of the colored toner satisfy the following relationship. Dc <Dt 16. The image forming apparatus according to claim 13, wherein the thickness Ht of the transparent toner and the thickness Hc of the colored toner satisfy the following relationship. Ht <Hc