JP2000089507A - Polymerized toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymerized toner which does not reduce its powder flowability or cause fogging, blurring, filming and the occurrence of white streaks even after repeated continuous printing by sticking plural specified silica modifications and a specified electrically conductive metal oxide as additives to the surface of a polymerized toner. SOLUTION: Silica having a surface made hydrophobic with an aminosilane and/or a silicone oil and having 10-50 nm particle diameter when added to the top of a toner and silica having a surface made hydrophobic with an aminosilane and/or a silicone oil and having 50-200 nm particle diameter when added to the top of a toner are stuck to the surface of a polymerized toner containing a bonding resin and a colorant. An electrically conductive metal oxide having <=100 Ωcm resistance is also stuck to obtain the objective polymerized toner which exhibits good image quality and stable durability in a simultaneous developing-cleaning system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and an electrostatic recording apparatus which perform cleaning simultaneously with development.
The present invention relates to an improvement in a polymerized toner used in a developing method in which a rotation direction at a contact portion between a photoconductor and a developing roller is rotated in the same direction.

[0002]

2. Description of the Related Art An electrostatic latent image formed in an electrophotographic apparatus or an electrostatic recording apparatus is developed by a developer, and then the formed developer image is transferred onto a transfer material such as paper.
It is fixed by various methods such as pressurization and solvent vapor. In this process, since a residual developer is left on the photoreceptor, a cleaning device for removing the residual developer is generally provided.

[0003] For example, an image forming apparatus having a configuration as schematically shown in section in FIG. 1 is generally used. In this apparatus, a cleaning device (2) including a photoconductor (1) and a cleaning blade (2a) disposed around the photoconductor (1), a charging device (3), an exposure device (4), a developing device, A device (5), a developing roller (8), a transfer device (6), and the like are provided. The surface of the photoreceptor (1) on which the required charging has been performed by the charging device (3) is selectively exposed by the exposure device (4), and an electrostatic latent image is formed. The latent image area is developed with a developer (toner) using the developing device (5). The developed toner image is transferred to a transfer paper (7) by a transfer device (6). After the transfer step, the toner remaining on the photoconductor is removed by a cleaning blade (2a) of the cleaning device (2).

However, in the above-described apparatus, since the residual toner accumulated in the cleaning apparatus has to be discarded, there is a problem that the maintenance is complicated and the surroundings of the apparatus and the environment are contaminated. Further, the photoreceptor is worn due to friction with the cleaning blade, and the image forming characteristics decrease with the number of prints. Further, when the cleaning device is installed, the size of the image forming apparatus is increased, and the degree of freedom in design is reduced.

In order to solve such a problem, cleaning is performed by suctioning and removing the residual developer adhering to the non-exposed area of the photoreceptor to the developing roller by the same developing device using a one-component developer. A method of simultaneously performing development and cleaning (hereinafter, may be simply referred to as a simultaneous development cleaning method) has been proposed (JP-A-62-203182 and JP-A-3-7972). In this method, the apparatus does not require a cleaning blade or the like. FIG. 2 shows a schematic sectional view of an example of such an image forming apparatus. In FIG. 2, reference numeral (9) denotes a toner layer thickness regulating member, and other reference numerals denote members or devices corresponding to those in FIG.

In the simultaneous developing and cleaning method using the apparatus shown in FIG. 2, the residual toner on the photoreceptor after the transfer step is collected in the developing apparatus according to the following principle. That is, the surface potential of the unexposed portion (non-latent image region) of the photoconductor (1) is Vo, the surface potential of the exposed portion (latent image region) is Vq, and the developing bias voltage applied to the developing roller (8) is Vb. ,
The surface potential Ve of the developing roller (8) is assumed to be equal to the developing bias voltage Vb. The electrostatic latent image on the photoreceptor is reversely developed with a one-component developer (toner) charged to the same polarity as the electrostatic latent image.

In this reversal development, the above surface potentials are set so as to satisfy the relationship of | Vo |> | Ve |> | Vq | (where Vo, Ve and Vq have the same polarity). In the latent image area of the photoconductor, a force in the direction of the photoconductor due to the potential difference | Ve−Vq | acts on the toner on the developing roller to perform development. After the transfer process, in the non-latent image area, the residual toner on the photosensitive member is subjected to a force in the direction of the developing roller due to the potential difference | Vo-Ve |, whereby the residual toner is collected, that is, the cleaning is performed. According to the simultaneous development cleaning method, a conventional cleaning device is not required.

In this developing method, a toner layer having a uniform thickness and a small thickness is formed on the developing roller (8) by the toner layer thickness regulating member (9). Further, as the toner, a non-magnetic one-component developer containing a binder resin and a colorant, containing no magnetic powder, and having high electric resistance is used.

However, according to the experimental results of the present inventors, in the above method, if the potential difference | Ve-Vq | is increased to obtain a sufficient image density, the potential difference | Vo-Ve | As the size becomes smaller, cleaning becomes incomplete and a ghost image appears. If the potential difference | Vo-Ve | is increased in order to improve the cleaning property, a satisfactory image density cannot be obtained because the potential difference | Ve-Vq | When the transferability of the toner on the photoreceptor to transfer paper is poor and the amount of residual toner is large, the above surface potentials Vo, Ve and Vq are appropriately controlled in order to satisfy both image density and cleaning performance. And the thickness of the toner layer formed on the developing roller,
In addition, it is necessary to reduce the amount of toner remaining after the transfer by controlling the rotation ratio between the photosensitive member and the developing roller to maintain the amount of developed toner properly. The range of these appropriate conditions was narrow and control was difficult.

In order to solve such a problem, there has been proposed a method using a spherical suspension polymerization toner having good transferability (Japanese Patent Application Laid-Open No. Hei 5-188637). However,
Although there were no problems with the initial image properties, repeated printing reduced the powder fluidity of the toner itself, increased fog and caused blurring, and a practically satisfactory non-magnetic one-component developer was obtained. Did not.

Regarding the stability to continuous printing, a method of sharing functions of fluidity and adhesion prevention by using silica having different particle diameters in combination has been conventionally used (Japanese Patent Laid-Open No. 7-26144).
No. 6) Further, a long-life toner capable of reproducing good image quality by using a combination of large-diameter silica whose surface is different and whose surface is treated with aminosilane and small-particle silica whose surface is hydrophobized. (See JP-A-10-39534)
However, in durable printing under a high-temperature and high-humidity environment, there has been a problem that the chargeability of the toner becomes insufficient and fogging increases. Further, by using a silica, a silane compound and a reactant of TiO (OH) ₂ treated with a silicone oil or the like in combination, it is possible to obtain fluidity and stable environmental characteristics as a positively charged toner (Japanese Patent Application Laid-Open No. 10-26841). However, there has been a problem that external additives are buried during durable printing and fogging occurs due to a decrease in fluidity. These are all manufactured by melt-mixing a colorant, a charge control agent, a release agent, and the like in a thermoplastic resin to uniformly disperse the composition, pulverizing and classifying the composition. It has only been confirmed that the effect is exhibited in the pulverized toner, and when the toner is necessarily applied to a polymer toner having a high sphericity, the effect is sufficiently exerted, particularly in a developing device adopting a simultaneous development cleaning method. The fact is that they have not.

[0012] The phenomenon that the fluidity is reduced and the fog and fuzz are increased by repeating the continuous printing using the polymerized toner are caused by the simultaneous development and cleaning method. The process units disposed around the body include a charging device, an exposure device, a developing device, a transfer device, and a cleaning device. Of these, if the cleaning device is removed, the toner remaining on the photoconductor after transfer until now is removed. Will be collected and reused in the developing device. As a result, as the number of printed sheets increases, toner that is difficult to transfer, toner with low charge,
A large amount of abnormal toner such as toner charged to the opposite polarity remains in the developing device and is developed, so that fog increases.

In a toner produced by suspension polymerization, conductive fine particles such as titanium oxide particles subjected to tin oxide / antimony treatment and silica fine particles subjected to hydrophobic treatment are each added to a colored resin particle (toner) in an amount of 0.1%. 05
There is known a toner to which about 3 parts by weight is added (Japanese Patent Laid-Open No.
-83096). However, this method does not solve the above-mentioned problem of the polymerized toner because it is an improvement in chargeability such as a time until a charge rise reaches a saturated charge amount and uniformity of charge amount distribution.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to improve a non-magnetic one-component developer used in a developing device employing a simultaneous development cleaning method so that the toner itself has reduced powder fluidity even when continuous printing is repeated. An object of the present invention is to provide a polymerized toner (hereinafter, may be simply referred to as a toner) free from generation of fogging and blurring and free from filming and white streaks.

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a photoreceptor employing a simultaneous development and cleaning system using toner having three types of specific external additives adhered to its surface. The present inventors have found that an image with stable image quality can be obtained even when continuous printing is repeated in a developing method in which the rotation direction of the developing roller is rotated in the same direction as the rotation direction of the contact portion.

[0016]

Thus, according to the present invention, a developing roll carrying a developer charged to the same polarity as the electrostatic latent image on the photoreceptor is arranged in contact with the photoreceptor, At the same time as developing the exposed area, the residual developer adhering to the non-exposed area of the photoreceptor is suctioned off to the developing roll side to be cleaned, and the rotation direction at the contact portion between the photoreceptor and the developing roll is rotated in the same direction. A polymerized toner containing at least a binder resin and a colorant used in a developing method, wherein the surface of the polymerized toner is (1) its surface is hydrophobized with aminosilane and / or silicone oil, and is externally added to the toner. When the particle size is 1
Silica A having a thickness of 0 nm to 50 nm (2) The surface of the silica A is hydrophobized with aminosilane and / or silicone oil to have a particle size of 5 when externally added to the toner.
Provided is a polymerized toner to which a conductive metal oxide C 2 having a silica B of 0 to 200 nm and a resistance value of 100 Ωcm or less is adhered.

Preferred embodiments include the following. (2) The adhesion amount of silica A to the polymerized toner is 0.1 to 2.0% by weight, and the adhesion amount of silica B is 0.3 to 2.0%.
% By weight, and the amount of the conductive metal oxide C deposited is 0.1 to 1.
The polymerized toner of 0% by weight. (3) The polymerized toner, wherein the conductive metal oxide comprises tin-antimony-doped titanium oxide. (4) The polymerized toner, wherein the conductive metal oxide comprises antimony-doped tin oxide. Hereinafter, the present invention will be described in detail.

The polymerized toner of the present invention is a so-called polymerized toner produced by a suspension polymerization method, and is obtained by adhering a predetermined external additive to polymer colored fine particles produced by a suspension polymerization method. is there. As a particularly preferred polymerizable monomer used for obtaining such a toner, a monovinyl monomer can be exemplified. The most preferred example of the monovinyl monomer is a monovinyl monomer. Specifically, styrene monomers such as styrene, vinyltoluene and α-methylstyrene; acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic Acrylic acid or methacrylic acid such as dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, etc. Derivatives of ethylene; ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; vinyls such as vinyl acetate and vinyl propionate Monovinyl compounds such as vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; nitrogen-containing vinyl compounds such as 2-vinyl pyridine, 4-vinyl pyridine and N-vinyl pyrrolidone; Monomers. These monovinyl monomers may be used alone, or a plurality of monomers may be used in combination. Of these monovinyl monomers, styrene monomers or derivatives of acrylic acid or methacrylic acid are preferably used.

In the present invention, any optional oil-soluble polymerization initiator and molecular weight modifier can be used as required.

Examples of the oil-soluble polymerization initiator include 4,4-azobis (4-cyanovaleric acid), 2,2-azobis (2-amidinopropane) dihydrochloride, and 2,2-azobis-2-methyl-N -1,1-bis (hydroxymethyl) -2-hydroxyethylpropioamide, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 Azo compounds such as' -azobis (1-cyclohexanecarbonitrile); methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxide -2-ethylhexanoate, di-isopropylperoxydicarbonate, di-t-butylperoxyisophthalate, etc. And the like can be exemplified oxides.

Of these, oil-soluble polymerization initiators, in particular,
A 10 hour half-life temperature of 60-80 ° C, preferably 65 ° C
An oil-soluble polymerization initiator selected from organic peroxides having a molecular weight of not more than 250 ° C. and having a molecular weight of 250 or less, in particular, t-butylperoxy-2-ethylhexanoate is an environment caused by volatile components such as odor during printing. It is suitable because it has little destruction. The amount of the polymerization initiator used is usually based on the polymerizable monomer,
It is 0.01 to 20% by weight. If the amount is less than 0.01% by weight, the polymerization rate is low, and if it is more than 20% by weight, the molecular weight is low, which is not preferable.

Examples of the molecular weight modifier used as needed in the present invention include, for example, t-dodecyl mercaptan, n
Mercaptans such as -dodecylmercaptan and n-octylmercaptan; and halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide. These molecular weight regulators can be added before the start of the polymerization or during the polymerization. The molecular weight modifier is generally used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the monomer.

The use of a crosslinkable monomer is effective for improving hot offset. The crosslinkable monomer is a monomer having two or more polymerizable carbon-carbon unsaturated double bonds. Specifically, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof; diethylenically unsaturated carboxylic esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N, N-divinylaniline, divinyl ether and the like A divinyl compound; a compound having three or more vinyl groups; and the like. These crosslinkable monomers can be used alone or in combination of two or more. These crosslinkable monomers are
It is used in an amount of usually 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of a non-crosslinkable monomer such as a monovinyl monomer.

In the present invention, it is preferable to use a macromonomer as a monomer in order to improve the balance between the preservability, the offset property and the low-temperature fixability. The macromonomer has a vinyl polymerizable functional group at a terminal of a molecular chain and has a number average molecular weight of usually 1,000 to 30,000.
0 oligomer or polymer. When a polymer having a small number average molecular weight is used, the surface portion of the polymer particles becomes soft, and the storage stability decreases. Conversely, when a polymer having a large number average molecular weight is used, the meltability of the macromonomer is deteriorated, and the fixability is lowered.

The macromonomer preferably has a glass transition temperature higher than the glass transition temperature of the polymer obtained by polymerizing the monovinyl monomer. Incidentally, the Tg of the macromonomer is calculated by using a conventional differential scanning calorimeter (DS
This is a value measured by a measuring device such as C).

Specific examples of the macromonomer used in the present invention include polymers obtained by polymerizing styrene, styrene derivatives, methacrylates, acrylates, acrylonitrile, methacrylonitrile, etc., alone or in combination of two or more. A macromonomer having a polysiloxane skeleton, which has a polymerizable double bond at the polymer terminal disclosed on pages 4 to 7 of JP-A-3-203746;
Examples having an arbitrary repeating structural unit can be given.

Among these macromonomers, polymers having a high glass transition temperature, in particular, polymers obtained by polymerizing styrene, methacrylate or acrylate alone or in combination thereof are suitable for the present invention. When a macromonomer is used, its amount is usually 0.01 to 100 parts by weight of the monovinyl monomer.
To 1 part by weight, preferably 0.03 to 0.8 part by weight.
If the amount of the macromonomer is too small, the preservability and the offset property are not improved. When the amount of the macromonomer is extremely large, the fixing property is reduced.

The polymer particles for the developer usually contain a colorant, and if necessary, a charge controlling agent, a release agent (wax), a dispersant for a colorant, and the like.

As the colorant, in the case of black pigment carbon black, it is particularly preferable to use one having a primary particle size of 20 to 40 nm. If it is less than 20 nm, dispersion of carbon black cannot be obtained, resulting in a toner with a lot of fog. On the other hand, if it is more than 40 nm, the amount of the polyvalent aromatic hydrocarbon compound becomes large, and a safety problem may occur. . Other black pigments include magnetic particles such as triiron tetroxide, iron manganese oxide, iron zinc oxide and iron nickel oxide.

Further, as dyes for magnetic color toners, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modant Red 30, C.I.
I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modant Blue 7, C.I. I.
Direct Gulin 6, C.I. I. Basic Green 4,
C. I. Basic Glin 6 etc. are pigments such as graphite, cadmium yellow, mineral first yellow, navel yellow, neftol yellow S, hanziero G, permanent yellow NCG, tartrazine lake, red mouth graphite,
Molybdenum orange, permanent orange GTR, pyrazolone orange, benzidine orange G, cadmium red, permanent red 4R, watching red calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, navy blue, cobalt blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Fast Sky Blue, Induslen Blue B
C, chrome grin, chromium oxide, pigment grin B,
Malachite green lake, final yellow logulin G and the like.

Examples of the magenta coloring pigment for full-color toner include C.I. I. Pigment Red 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 1
5, 16, 17, 18, 19, 21, 22, 23, 3
0, 31, 32, 37, 38, 39, 40, 41, 4
8, 49, 50, 51, 52, 53, 54, 55, 5
7, 58, 60, 63, 64, 68, 81, 83, 8
7, 88, 89, 90, 112, 114, 122, 12
3, 163, 202, 206, 207 and 209;
C. I. Pigment Violet 19, C.I. I. Butt Red 1, 2, 10, 13, 15, 23, 29 and 3
5 etc. are magenta dyes as C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 4
9, 81, 82, 83, 84, 100, 109 and 1
21, C.I. I. Disperse Red 9, C.I. I. Solvent violet 8, 13, 14, 21 and 27,
C. I. Oil-soluble dyes such as Disperse Violet 1;
C. I. Basic Red 1, 2, 9, 12, 13, 1
4, 15, 17, 18, 22, 23, 24, 27, 2
9, 32, 34, 35, 36, 37, 38, 39 and 40; I. Basic violet 1, 3, 7, 1
And basic dyes such as 0, 14, 15, 21, 25, 26, 27 and 28.

Cyan color pigments for full-color toners include C.I. I. Pigment Blue 2, 3, 15, 16 and 17, C.I. I. Bat Blue 6, C.I. I. Acid Blue 45 and a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton.

The yellow color pigments for full-color toners include C.I. I. Pigment Yellow 1, 2, 3, 4,
5, 6, 7, 10, 11, 12, 13, 14, 15, 1,
6, 17, 23, 65, 73, 83, 138 and 18
0, C.I. I. Bat Yellow 1, 3, and 20 and the like.

In the present invention, for the purpose of, for example, uniformly dispersing the colorant in the toner particles (polymer colored fine particles),
Fatty acids such as oleic acid and stearic acid or Na,
K, Ca, Mg, fatty acid metal salts composed of metals such as Zn,
A dispersing aid such as a silane or titanium coupling agent;
May be used. Such lubricants and dispersants are usually 1/1000 to 1/1 based on the weight of the colorant.
Used in proportions.

It is desirable to add various charge control agents and release agents as a polymerizable monomer composition in addition to the colorant and the polymerizable monomer for the purpose of controlling the chargeability of the toner.

Examples of the charge control agent include commonly used nigrosine compounds having a positively-charged nitrogen-containing group, triphenylmethane, quaternary ammonium salts, and hydrogen halide salts of alkylamines. More specifically, Bontron N1, N4, N21 (Nigrosine, manufactured by Orient Chemical), Nigrosine EX (manufactured by Orient Chemical),
Copy Blue PR (manufactured by Hoechst), quaternary ammonium salt-containing resin (manufactured by Fujikura Kasei, FCA-201-PS),
Isostatic control resins can be mentioned. In the present invention, a negatively chargeable charge control agent can be used as necessary. Metal complexes of organic compounds, metal-containing dyes such as Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.), T-
77 (manufactured by Hodogaya Chemical), Bontron S-34 (manufactured by Orient Chemical), Bontron E-84 (manufactured by Orient Chemical), or a sulfonic acid group-containing resin (FCA-1001-NS manufactured by Fujikura Kasei) Can be mentioned. The charge control agent is usually 0.01 to 10 parts by weight, preferably 0.0 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer.
Use 3-5 parts by weight.

Specific examples of the release agent include low-molecular-weight polyolefin waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, and low-molecular-weight polybutylene; low-molecular-weight oxidized polypropylene having a low molecular weight; Terminal-modified polyolefin waxes such as terminal-modified polypropylene and block polymers of these and low-molecular-weight polyethylene, molecular-end-oxidized low-molecular-weight polyethylene, low-molecular-weight polyethylene having molecular terminals substituted with epoxy groups and block polymers of these and low-molecular-weight polypropylene; candelilla, Carnauba,
Plant natural waxes such as rice, wood wax, jojoba, etc .; petroleum waxes such as paraffin, microcrystalline, petrilactam and modified waxes; mineral waxes such as montan, ceresin, ozokerite; synthetic waxes such as Fischer-Tropsch wax; One type or two or more types such as functional ester compounds are exemplified. Among them, synthetic waxes, especially trade names “FT-100”, “FT-0030”, “FT-300” manufactured by Shell MDS Co., Ltd.
0050 "," FT-0070 "," FT-016
5 "," FT-1155 "," FT-60S ", etc.
"Viscol 660P" and "Viscol 5" of low molecular weight polypropylene wax such as Fischer-Tropsch wax such as Sasol wax manufactured by Sasol.
50P "(both trade names, manufactured by Sanyo Kasei Co., Ltd.), microcrystalline wax, and polyfunctional ester compounds such as pentaerythritol tetramyristate and pentaerythritol tetrastearate are preferred. Among them, DSC curves measured by a differential scanning calorimeter , The endothermic peak temperature at the time of temperature rise is 30 to 200 ° C, preferably 50 to 200 ° C.
Those in the range of 180 ° C and 80 to 160 ° C are particularly preferred. The endothermic peak temperature is ASTM D3418-82.
Is the value measured by The release agent is monomer 100
It is used in a proportion of usually 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight, based on parts by weight.

The polymerization of the polymerizable monomer is usually performed by a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, or the like. In the present invention, it is particularly preferable to carry out the polymerization by a suspension polymerization method.

The dispersant used in the suspension polymerization method includes:
It contains a colloid of a poorly water-soluble metal compound.
Examples of poorly water-soluble metal compounds include sulfates such as barium sulfate and calcium sulfate; barium carbonate, calcium carbonate,
Carbonates such as magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide and ferric hydroxide; it can.
Among these, a dispersant containing a colloid of a poorly water-soluble metal hydroxide is preferable because it can narrow the particle size distribution of the polymer particles and improves the sharpness of the image. After completion of the polymerization reaction, toner particles can be obtained by removing water-soluble metal salts remaining on the particle surface by usual pickling and washing with water, followed by dehydration and drying.

The method of preparing a dispersion stabilizer containing a colloid of a poorly water-soluble metal hydroxide is based on the pH of an aqueous solution of a water-soluble polyvalent metal salt.
Is preferably adjusted to 7 or more with an aqueous solution of an alkali metal hydroxide, and a colloid of a poorly water-soluble metal hydroxide is preferably used.

The dispersion stabilizer is used usually in a proportion of 0.1 to 20 parts by weight based on 100 parts by weight of the monomer. If this ratio is less than 0.1 part by weight, it is difficult to obtain sufficient droplet dispersion stability of the polymerizable monomer composition, and aggregates of polymer particles are easily generated. Conversely, if it exceeds 20 parts by weight, the viscosity in the aqueous dispersion medium increases, and the distribution of the particle diameter of the polymerized toner broadens, so that the yield decreases. The reaction ratio between the water-soluble polyvalent metal salt and the alkali metal hydroxide is such that the chemical equivalent ratio A of the alkali metal hydroxide to the water-soluble polyvalent metal salt is in the range of 0.4 ≦ A ≦ 1.0.

In the present invention, if necessary, a dispersant containing a water-soluble polymer can be used. Examples of the water-soluble polymer include polyvinyl alcohol, methyl cellulose, gelatin and the like. In the present invention, it is not necessary to use a surfactant,
It can be used to stably carry out polymerization within a range where the environmental dependence of the charging characteristics does not increase.

The colloid of the poorly water-soluble metal compound used in the present invention has a number particle size distribution D50 (50% cumulative value of the number particle size distribution) of 0.5 μm or less and a D90 (9% of the number particle size distribution).
(0% cumulative value) is preferably 1 μm or less.

The production of the colored fine particles is specifically performed by the following method. That is, raw materials for colored fine particles such as a colorant, a release agent, a charge control agent, and other additives are mixed in a polymerizable monomer (preferably a vinyl-based monomer) using a mixing and dispersing machine such as a bead mill. Disperse in an aqueous medium containing a dispersion stabilizer and stir the suspension to form droplets. Next, a polymerization initiator is added thereto, and the droplets are further granulated to be reduced to the size of the toner to obtain colored fine particles. The granulation method is
Although not particularly limited, a method in which a rotor that rotates at a high speed and a stator that surrounds the rotor and has a small hole or a comb-tooth and that is circulated is preferably used.

The dispersion state of the monomer composition dispersion is such that the volume average particle diameter of the monomer composition droplets is usually 4 to 9 μm, preferably 5 to 8 μm. If the particle size of the droplet is too large, the size of the toner particles increases, and the resolution of the image decreases. The volume average particle diameter / number average particle diameter of the droplet is usually 1 to 3.0, preferably 1 to 2.0. If the particle size distribution of the droplets is wide, variation in fixing temperature occurs, fog,
Problems such as filming occur. The droplets preferably have a particle size distribution of 30% by volume or more, preferably 60% by volume or more in the range of the volume average particle size ± 1 μm.

In the present invention, it is preferred that after the monomer composition dispersion liquid is obtained, it is charged into a polymerization reactor and polymerized. Specifically, the monomer composition is added to the aqueous medium in a dispersion preparation container to prepare a monomer composition dispersion, and the monomer composition is placed in another container (polymerization reaction container). ), Charged in the container, and polymerized. In a method in which a dispersion is obtained in a polymerization reactor and the polymerization reaction is carried out as it is, as in the conventional suspension polymerization method, scale is generated in the reactor, and large amounts of coarse particles are easily generated.

The timing of adding the oil-soluble initiator is determined by adding a colorant, a releasing agent, a charge controlling agent, and other additives to a vinyl monomer and dispersing the monomer uniformly by a bead mill or the like. An equal composition is prepared, and then the mixture is poured into an aqueous dispersion medium, stirred well, and after the droplet particles become uniform, an oil-soluble polymerization initiator is added, mixed, and further rotated at high speed. After granulating to a particle size close to the toner particles using a shearing stirrer, at a temperature of 5 to 120C, preferably 35 to 9C.
The suspension polymerization is carried out at a temperature of 5 ° C. If the temperature is lower than this, a polymerization initiator having high catalytic activity is used, so that it becomes difficult to control the polymerization reaction. Conversely, at higher temperatures,
The stability of the polymer particles is reduced, the particle size distribution is disturbed, and scale adheres to the polymer can wall.

The polymer particles thus obtained have a volume average particle size of usually 2 to 10 μm, preferably 2 to 9 μm.
m, particularly preferably 3 to 8 μm. Further, volume average particle diameter (dv) / number average particle diameter (dp) is usually
1.7 or less, preferably 1.5 or less, more preferably 1.3 or less colored fine particles are obtained. Further, the particles obtained in this way, further polymerizable monomer, polymerization initiator,
It is also possible to obtain a polymerized toner having a core-shell structure, that is, a so-called capsule type polymerized toner, by adding a charge control agent and polymerizing.

In the present invention, as described above, the shell monomer can be further reacted. The colored fine particles obtained by the above-described method are core particles, and a polymer having a glass transition temperature higher than the glass transition temperature (Tg) of the polymer constituting the core particles is defined as a shell. As a monomer constituting the monomer for the shell, it is possible to use a monomer which forms a polymer having a glass transition temperature exceeding 80 ° C., such as styrene and methyl methacrylate, alone or in combination of two or more. it can. It is necessary to set the glass transition temperature of the polymer composed of the shell monomer at least higher than the glass transition temperature of the polymer forming the core particles. The glass transition temperature of the polymer obtained from the shell monomer is generally higher than 50 ° C. and 120 ° C. or lower, preferably higher than 60 ° C. and 110 ° C. or lower, more preferably 80 ° C. in order to improve the storage stability of the polymerized toner. ° C
Exceed 105 ° C or less. The difference in glass transition temperature between the polymer forming the core particles and the polymer comprising the shell monomer is usually 10 ° C. or higher, preferably 20 ° C. or higher, more preferably 30 ° C. or higher.

When the shell monomer is polymerized in the presence of the core particles (colored fine particles), it is preferable that the shell monomers be formed into droplets smaller than the number average particle diameter of the core particles. If the particle diameter of the droplets of the monomer for the shell is large, the shell cannot be uniformly attached, so that the storage stability tends to decrease. To make the shell monomer small droplets, a mixture of the shell monomer and the aqueous dispersion medium, for example, using an ultrasonic emulsifier,
Perform fine dispersion processing. It is preferable to add the obtained aqueous dispersion to a reaction system in which core particles are present.

The monomer for shell is not particularly limited by the solubility in water at 20 ° C., but the monomer having high solubility in water having a solubility in water at 20 ° C. of 0.1% by weight or more is rapidly added to the core particles. , It is easy to obtain polymer particles having good storage properties. Monomers having a solubility in water at 20 ° C. of 0.1% by weight or more include (meth) acrylates such as methyl methacrylate and methyl acrylate; amides such as acrylamide and methacrylamide; and cyanides such as acrylonitrile and methacrylonitrile. Vinyl compounds; nitrogen-containing vinyl compounds such as 4-vinylpyridine; vinyl acetate, acrolein and the like.

On the other hand, the solubility in water at 20 ° C. is 0.1
When the monomer is used in an amount of less than% by weight, the transfer to the core particles becomes slow. Therefore, as described above, it is preferable to polymerize the monomer into fine droplets. Even when a monomer having a solubility in water at 20 ° C. of less than 0.1% by weight is used, an organic solvent having a solubility in water at 20 ° C. of 5% by weight or more is added to the reaction system to prepare a single monomer for the shell. The body moves to the core particles quickly, and it becomes easier to obtain polymer particles having good storage stability. The solubility in water at 20 ° C. is 0.
Less than 1% by weight of the shell monomer includes styrene, butyl acrylate, 2-ethylhexyl acrylate,
Examples include ethylene and propylene.

The solubility in water at 20 ° C. is 0.1% by weight.
Examples of the organic solvent preferably used when less than the shell monomer is used include lower alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butyl alcohol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; Cyclic ethers such as dioxane; ethers such as dimethyl ether and diethyl ether; amides such as dimethylformamide. The organic solvent has a solubility of the shell monomer in a dispersion medium (total amount of water and the organic solvent) of 0.1.
An amount of 1% by weight or more is added. Although the specific amount of the organic solvent varies depending on the type and amount of the organic solvent and the shell monomer, it is usually 0.1 to 100 parts by weight of the aqueous dispersion medium.
It is 1 to 50 parts by weight, preferably 0.1 to 40 parts by weight, more preferably 0.1 to 30 parts by weight. The order of adding the organic solvent and the shell monomer to the reaction system is not particularly limited, but in order to facilitate the transfer of the shell monomer to the core particles and to easily obtain polymer particles having good storability, It is preferable to add the organic solvent first, and then add the shell monomer.

The solubility in water at 20 ° C. is 0.1% by weight.
When a monomer having less than 0.1% by weight and a monomer having less than 0.1% by weight are used in combination, a monomer having a solubility in water at 20 ° C. of 0.1% by weight or more is added and polymerized. Preferably, a solvent is added, and a monomer having a solubility in water at 20 ° C. of less than 0.1% by weight is added for polymerization. According to this addition method, the Tg of the polymer obtained from the monomer polymerized in the presence of the core particles in order to adjust the fixing temperature of the polymerized toner is adjusted.
Alternatively, the amount of the monomer added can be appropriately controlled.

In the present invention, it is preferable to mix the charge controlling agent with the monomer for the shell, and then add the mixture to the reaction system and polymerize the mixture to improve the positive or negative chargeability of the toner. Specific examples of the positive charge control agent include Bontron N
1, N4, N21 (Nigrosine, manufactured by Orient Chemical), Nigrosine EX (manufactured by Orient Chemical), quaternary ammonium salt-containing resin (FCA-201-, manufactured by Fujikura Kasei)
PS).

Specific examples of the negative charge control agent include Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.), T-77 (manufactured by Hodogaya Chemical Co., Ltd.), Bontron S-34 (manufactured by Orient Chemical Company), Bontron E-84 (manufactured by Orient Chemical Co., Ltd.). Orient Chemical Co., Ltd.), sulfonic acid group-containing resin (FCA-1 manufactured by Fujikura Kasei)
001-NS). The charge controlling agent is usually 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the shell monomer.
Used in a proportion of 5 parts by weight.

As a specific method for polymerizing the shell monomer in the presence of the core particles, the shell monomer is added to the reaction system of the polymerization reaction performed to obtain the core particles, and the shell monomer is continuously added. Or a method in which core particles obtained in another reaction system are charged, a monomer for a shell is added thereto, and polymerization is carried out in a stepwise manner. The monomer for the shell component can be added to the reaction system all at once, or can be added continuously or intermittently using a pump such as a plunger pump.

In the polymerized toner of the present invention, it is preferable to add a water-soluble radical initiator when adding the shell monomer, in order to easily obtain core-shell type polymer particles. When a water-soluble polymerization initiator is added during the addition of the shell monomer, the water-soluble radical initiator enters near the outer surface of the core particle to which the shell monomer has migrated, and the polymer ( It is considered that this is because a shell is easily formed.

Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 4,4-azobis (4-cyanovaleric acid) and 2,2-azobis (2-amidinopropane) dihydrochloride Azo initiators such as 2,2,2-azobis-2-methyl-N-1,1-bis (hydroxymethyl) -2-hydroxyethylpropioamide; oil-soluble initiators such as cumene peroxide and redox catalysts Combinations; and the like. The amount of the water-soluble polymerization initiator is usually 0.01 to 20 parts by weight based on the polymerizable monomer B.

In the case of the polymerized toner of the present invention having a core-shell structure, the weight ratio of the monomer for core particles (polymer forming the core particles) to the monomer for shell is usually from 80/20 to 80/20. 99.9 / 0.1. Within this range, the storage stability will be extremely good. The shell has an average thickness of 0.001 to 1.0 μm, preferably 0.001 to 1.0 μm.
3 to 0.5 μm, more preferably 0.005 to 0.2 μm
It is considered to be. As the thickness increases, the fixability decreases, and as the thickness decreases, the storability decreases. In the developer having the core-shell structure of the present invention, it is not necessary that the entire core portion is covered with the shell. When the core particle size and shell thickness can be observed with an electron microscope, the core size and shell thickness can be obtained by directly measuring the particle size and shell thickness selected at random from the observation photograph. When it is difficult to observe the above, it can be calculated from the particle size of the core particles and the amount of the monomer forming the shell.

The polymer colored fine particles thus obtained have a volume average particle size of 5 to 10 μm, preferably 6 to 9 μm.
m. If the volume average particle size is too small, the powder flowability will decrease if the number of printed sheets increases, and fog will increase. Conversely, if it is too large, the resolution will decrease, which is not preferable. The volume average particle size is a value measured by a multisizer (manufactured by Coulter Inc.). In addition, the longest diameter (d
l) and the shortest diameter (ds) ratio (dl / ds) is 1.0 to
When a toner having a substantially spherical shape in the range of 1.3, preferably 1.0 to 1.2 is used, the transfer efficiency to transfer paper becomes as high as 90% or more, so that both image density and cleaning property are satisfied. Appropriate conditions for the surface potentials Vo, Ve and Vq, the thickness of the toner layer formed on the developing roller, and the rotation ratio between the photosensitive member and the developing roller are widened. The longest diameter and the shortest diameter were measured by taking a photograph of 100 toner particles with a scanning electron microscope, reading the photograph with a Nexus 9000 type image processing apparatus, and dividing the long diameter of the toner by the short diameter (dl).
/ Ds).

The external additives used in the polymerized toner of the present invention are as follows: (1) The surface of the external additive is hydrophobized with aminosilane and / or silicone oil, and the particle size when externally added to the toner is 1
Silica A having a thickness of 0 nm to 50 nm (2) The surface of the silica A is hydrophobized with aminosilane and / or silicone oil to have a particle size of 5 when externally added to the toner.
Silica B having a thickness of more than 0 nm and 200 nm or less (3) Resistance value 100 Ωcm or less, preferably 60 Ωcm
At least three kinds of the following conductive metal oxides C 1 are used.

The ratio of each of these three types is silica A / silica B / conductive metal oxide C = 0.1 to weight ratio.
2.0 / 0.3-2.0 / 0.1-1.0, preferably 0.2-1.0 / 0.4-1.0 / 0.2-0.5 . Within this range, initially
An excellent toner that satisfies high image resolution, high ID, and low area fog can be obtained even in 10,000-sheet durable printing at high image resolution, high ID, low ground fog, and at normal temperature and normal humidity, high temperature, high humidity, and low temperature and low humidity. The amount of each component adhered to the polymer colored particles is 0.1 to 2.0% by weight, preferably 0.2 to 1.0% by weight for silica A, and 0.3 to 2.0% for silica B. % By weight, preferably 0.4 to 1.0% by weight, and the conductive metal oxide C is 0.1 to 1.0, preferably 0.2 to 0.6.

(1) The silica A is preferably obtained by subjecting the surface of colloidal silica to a hydrophobic treatment. An aminosilane-based coupling agent or silicone oil is used alone as a hydrophobizing agent, or a coating is made using both agents. Preferably, the following treatment methods using both treatment agents are suitable. The coating method is as follows. The colloidal silica to be treated is placed in a closed Henschel mixer heated to 70 ° C., and aminosilane diluted with alcohol is added so that the treatment amount of the aminosilane-based coupling agent with respect to the colloidal silica is 5% by weight. In addition, the mixture was stirred at high speed.
After drying the obtained colloidal silica at 120 ° C., it is again put into a Henschel mixer, and while stirring, silicone oil is added to the colloidal silica so as to be 2% by weight, followed by high-speed stirring at room temperature for 2 hours. 1 at 160 ° C
By subjecting the surface of the colloidal silica to a hydrophobizing treatment by performing a heat treatment for 5 hours, the hydrophobizing treatment can be performed. Examples of the aminosilane-based coupling agent include γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -γ-aminopropylmethoxydimethoxysilane,
γ-anilinopropyltrimethoxysilane and the like. Examples of the silicone oil include polydimethylsiloxane, amino-modified polydimethylsiloxane, alkyl-modified polydimethylsiloxane, and fluorine-modified polydimethylsiloxane. Examples of such silica include H
DKH2150, HDKH2050EP, HDKH30
50EP (all trade names; Clariant), RE
A200, NAG200Y, and NA90H (all of which are trade names; manufactured by Nippon Aerosil Co., Ltd.) and the like.

(2) Like silica A, silica B is silane that has been subjected to a hydrophobizing treatment by aminosilanization.
A specific example of such silica is NEA50 (trade name; manufactured by Nippon Aerosil Co., Ltd.). The treating agent used for the hydrophobic treatment of silica A and the treating agent used for the hydrophobic treatment of silica B may be the same or different.

(3) The conductive metal oxide C has the above-mentioned electric resistance, and has a particle size of 0.05 to 3 μm.
m, preferably 0.1 to 1 μm. If the particle size is too large, the adhesive force to the toner becomes small, and it becomes a free external additive and transfers from the toner to the photoconductor at the contact portion between the developer carrier and the photoconductor, and adheres to the photoconductor without being transferred and collected. However, there is a problem that adverse effects such as inhibiting the primary potential of the photoreceptor occur.If too small, the toner is buried in the toner surface layer during durable printing, and the auxiliary effect of triboelectric charging near the toner empty is not recognized. There's a problem. The electric resistance value of the conductive metal oxide is a value measured by a dielectric loss measuring device. If the resistance value is too high, the conductivity will decrease, and it tends to be difficult to obtain a desired charge amount.

Preferred examples of such a conductive metal oxide include transition metal oxides surface-treated with antimony, such as tin / antimony-doped titanium oxide and antimony-doped tin oxide. A specific example of tin / antimony-doped titanium oxide is EC-300.
(Trade name; manufactured by Titanium Industry Co., Ltd.), ET-300, HJ-
1, HI-2 (all trade names; manufactured by Ishihara Sangyo), W-
P (trade name; manufactured by Mitsubishi Materials Corporation) and the like.
Specific examples of antimony-doped tin oxide include SN-1
00P (trade name; manufactured by Ishihara Techno), T-1 (trade name;
Examples are SH-S (trade name; manufactured by Nippon Chemical Industry Co., Ltd.) and the like.

The attachment of these external additives is usually carried out by stirring the external additives and toner particles in a mixer such as a Henschel mixer. Before mixing with the toner particles, the three types of external additives can be individually or arbitrarily combined and pulverized. Further, the external additive may be brought into contact with the toner particles at the same time, or may be brought into contact sequentially.
Three of the external additives may be mixed in advance.

The above-described image forming apparatus using the polymerized toner of the present invention includes a photoreceptor, a unit for charging the surface of the photoreceptor, a unit for forming an electrostatic latent image on the surface of the photoreceptor, and a housing for the polymerized toner. Means for supplying the polymerized toner and developing the electrostatic latent image on the surface of the photoconductor to form a toner image, and means for transferring the toner image from the surface of the photoconductor to a transfer material.

An image forming apparatus using the polymerized toner of the present invention will be described in detail based on an embodiment shown in the drawings. As shown in FIG. 2, in the image forming apparatus according to the present embodiment, a photosensitive drum 1 as a photosensitive member is rotatably mounted in the direction of arrow A. The photosensitive drum 1 has a photoconductive layer provided on the outer peripheral surface of a conductive support drum. The photoconductive layer is made of, for example, an organic photoconductor, a selenium photoconductor, a zinc oxide photoconductor, an amorphous silicon photoconductor, or the like.

Around the photosensitive drum 1, along a circumferential direction thereof, a charging roller 3 as a charging unit, a laser beam irradiation device 4 as a latent image forming unit, a developing roller 8 as a developing unit, and a developing roller 8 as a transferring unit. A transfer roller 6 is provided.

The charging roller is used to uniformly charge the surface of the photosensitive drum positively or negatively. By applying a voltage to the charging roller and bringing the charging roller into contact with the photosensitive drum, the surface of the photosensitive drum is charged. It is charged. The charging roller 3 can be replaced with charging means using corona discharge.

The laser beam irradiation device 4 irradiates the surface of the photosensitive drum with light corresponding to the image signal, and irradiates the uniformly charged surface of the photosensitive drum with light in a predetermined pattern.
The purpose is to form an electrostatic latent image on a portion irradiated with light (in the case of reversal development) or to form an electrostatic latent image on a portion not irradiated with light (in the case of regular development). As another latent image forming unit, there is a unit formed of an LED array and an optical system.

The developing roller is for attaching toner to the electrostatic latent image on the photosensitive drum 1. In the reversal development, the toner adheres only to the light-irradiated portion. A bias voltage is applied between the developing roller and the photosensitive drum so that the toner adheres.

Next to the developing roller, a developing roller 8 and a supply roller 1 are provided in a casing 11 in which the toner 10 is stored.
2 are provided. The developing roller is disposed so as to be in partial contact with the photosensitive drum, and is in a direction B opposite to the photosensitive drum.
It is designed to rotate. The supply roller 12 contacts the developing roller, rotates in the same direction C as the developing roller, and supplies toner to the outer periphery of the developing roller.

Around the developing roller, at a position between the point of contact with the supply roller and the point of contact with the photosensitive drum,
A developing roller blade 9 as a layer thickness regulating means is provided. The blade 9 is made of conductive rubber or stainless steel, and is used to inject electric charge into the toner.
A voltage of 200 V | to | 600 V | is applied. Therefore, the electric resistance value of the blade 9 is 10 6 Ωcm.
The following is preferred.

The casing 10 of the image forming apparatus of the present invention contains the toner 10 of the present invention. Toner 10
Contains the polymer particles. Further, since the toner of the present invention has a relatively sharp particle size distribution, when the layer of the developing roller is formed, it can be substantially formed into one or two layers by the layer thickness regulating means. Excellent reproducibility.

The transfer roller 6 is for transferring the toner image on the surface of the photosensitive drum formed by the developing roller to the transfer material 7. Examples of the transfer material include paper and OHP sheets. Examples of the transfer unit include a corona discharge device and a transfer belt other than the transfer roller.

The toner image transferred to the transfer material is fixed to the transfer material by fixing means. The fixing unit usually includes a heating unit and a pressing unit. The toner transferred to the transfer material is heated by a heating unit to melt the toner, and the melted toner is pressed and fixed to the surface of the transfer material by a pressing unit.

As a method for improving the chargeability of a low-charged toner, the developing device uses the same rotation direction at the contact portion between the photosensitive member and the developing roller, and the peripheral speed of the developing roller is the peripheral speed of the photosensitive member. At least 1.1 times, preferably at least 1.3 times.

Further, the nip width of the developing roller with respect to the photosensitive member is preferably 1 mm or more. If it is less than this, the sliding force is weak. The surface hardness of the developing roller is 40 or more (JIS
A) is preferred. If it is lower than this, the sliding force is weak.

It is preferable that at least the surface of the developing roller is made of a rubber elastic material, and that the circumferential surface roughness is 10 μm or less and the axial surface roughness is 10 μm or less. If the surface roughness is larger than 10 μm, unevenness in the thickness of the toner thin layer tends to occur due to unevenness of the surface of the developing roller, and the charge amount of the toner particles varies due to the difference in the triboelectric charging property between the thick and thin portions. Printing quality will be degraded.

The elastic body constituting the surface of the developing roller is not particularly limited, but includes styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, silicone Rubber or the like is used.

The means for controlling the surface roughness of the developing roller to the above range is not particularly limited, but a method of polishing the outer peripheral surface of the developing roller with a cylindrical cutting machine or the like, or a method of polishing the surface and then using a rubber elastic body. A coating method or the like is used.

[0085]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to only these examples. Parts and percentages are by weight unless otherwise specified.

The methods for measuring physical properties in the examples and comparative examples are as follows.

(1) Particle Size and Shape of Toner The volume average particle size and the number average particle size of the polymer particles were measured using a Multisizer (manufactured by Coulter Inc.). The measurement with this multisizer was performed with an aperture diameter of 100 μm.
m, medium: Isoton II, concentration: 10%, number of measured particles: 50,000. The shape of the toner is photographed with a scanning electron microscope, and the photograph is taken with Nexus 900.
The image was read by a 0-type image processing apparatus, and a value (dl / ds) obtained by dividing the major axis of the toner by the minor axis was measured. The measurement number of the toner at this time was 100 pieces.

(2) Physical Properties and Particle Size of External Additive The particle size of the external additive was measured by mixing a single external additive with the toner, and measuring 100 externally added toners with a scanning electron microscope. It is a value obtained by taking a photograph, reading the photograph with a Nexus 9000 type image processing apparatus, and measuring the size of the external additive particles on the toner surface. -Electric resistance value The volume specific resistance of the external additive is obtained by pressing the external additive into a disk having a diameter of 55 mm and a thickness of 2 mm, and measuring the dielectric loss (trade name: TRS-10, manufactured by Ando Electric Co., Ltd.). ) And temperature 3
The measurement was performed at 0 ° C. and a frequency of 1 kHz.

(3) Evaluation of Initial Image Quality Measurement of Print Density (ID) The print density (ID) was evaluated using a Macbeth reflection densitometer.
The “solid black portion” was measured, and 1.4 or more was evaluated as “○”, 1.3 or more as “Δ”, and less than 1.3 as “x”.・ Measurement of photoreceptor fog The toner in the fog area on the photoreceptor drum is transferred to paper with a mending tape, and the reflectance value measured with a whiteness meter is reflected when only the mending tape is affixed to the paper. The ratio was subtracted from the value measured by a whiteness meter, and a developer of 2 or less was evaluated as ○, 5 or less as Δ, and 10 or more as x. -The resolution was evaluated by printing a one-dot line and a one-dot white line, observing whether or not the image quality was reproduced by an optical microscope, and evaluating the following criteria. ○: One dot line and one dot white line are reproduced. Δ: One-dot line and one-dot white line cannot be reproduced, but two-dot line and two-dot white line can be reproduced. X: A 2-dot line and a 2-dot white line could not be reproduced. (4) Continuous printing evaluation Continuous printing was performed from the beginning at 30 ° C. × 80% (relative humidity) with the above-mentioned printer, and the print density was 1.35 or more with a reflection densitometer (manufactured by Macbeth). A toner with a fog of 5% or less measured by a whiteness meter (manufactured by Nippon Denshoku Co., Ltd.) can continue for 10,000 sheets or more (○). A toner that can continue for 5,000 sheets or more (△). ).

Example 1 83 parts of styrene, 17 parts of n-butyl acrylate, 7 parts of carbon black (trade name “# 25B”, manufactured by Mitsubishi Chemical Corporation, primary particle size 40 nm), charge control agent “N1” (product) Name; manufactured by Orient Chemical Co., Ltd.)
03 parts, divinylbenzene 0.6 parts, t-dodecylmercaptan 1.5 parts, and pentaerythritol tetramitistylate 5 parts were dispersed at room temperature by a bead mill to obtain a uniform mixed solution. While stirring the mixture, 5 parts of t-butylperoxy-2-ethylhexanoate was added, and stirring was continued until the droplets became uniform.

On the other hand, in an aqueous solution obtained by dissolving 9.5 parts of magnesium chloride (a water-soluble polyvalent metal salt) in 250 parts of ion-exchanged water, 4.8 parts of sodium hydroxide (alkali metal hydroxide) was added to 50 parts of ion-exchanged water. The aqueous solution in which was dissolved was gradually added under stirring to prepare a magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) dispersion. The polymerizable monomer composition was charged into the colloid, and the mixture was subjected to high shear stirring at a rotation speed of 12000 rpm using a TK homomixer to granulate droplets of the polymerizable monomer mixture. The aqueous dispersion of the granulated polymerizable monomer mixture is put into a reactor equipped with a stirring blade, a polymerization reaction is started at 90 ° C., polymerization is performed for 8 hours, and then cooling is performed. I got

While stirring the aqueous dispersion of the polymer particles obtained above, the pH of the system was adjusted to 4 or less with sulfuric acid, and acid washing was performed. After water was separated by filtration, 500 parts of ion-exchanged water was newly added. In addition, the slurry was reslurried and washed with water. After that, dehydration and water washing were repeated several times again, and the solid content was separated by filtration, followed by drying at 45 ° C. for one day and night with a dryer to obtain polymer particles. The volume average particle diameter of the polymer particles was 9.5 μm, the volume average particle diameter (dv) / number average particle diameter (dp) was 1.28, and dl / ds was 1.1, which was almost spherical.

To 100 parts of the toner thus obtained, 0.6 part of colloidal silica (trade name “HVK2150”, manufactured by Clariant) and 0.6 part of colloidal silica (trade name “NE”)
A50 ", manufactured by Nippon Aerosil Co., Ltd.) 1.0 part and" EC30
0 "(trade name; manufactured by Titanium Industry Co., Ltd., electric resistance value: 46Ωc)
m, particle size: 400 nm) and 0.3 parts by weight.
Using a L Henschel mixer for 2.5 minutes at a rotation speed of 14
The mixture was mixed at 00 rpm to obtain a polymerized toner.

The toner obtained as described above is rotated in the same direction at the contact portion between the photoconductor and the developing roll, and the non-magnetic toner whose peripheral speed of the developing roll is 1.5 times the peripheral speed of the photoconductor. When the printing was evaluated using a one-component contact developing cleaner-less positive charging printer, good image quality was obtained in the initial stage. Further, continuous printing evaluation was performed on 10,000 sheets at normal temperature, normal humidity, and high temperature, high humidity, low temperature, and low humidity environments, respectively. As a result, good image quality without fog was obtained, and no filming occurred on the developing roller and the photoconductor. Table 1 shows the results.
It was shown to.

[Examples 2 to 5, Comparative Examples 1 to 9] Example 1
, The charge control agent "Bontron N1" (trade name; manufactured by Orient Chemical Co., Ltd.) and 0.03 part were changed to 1 part of charge control resin (trade name "# 207"; manufactured by Fujikura Kasei Co., Ltd.) Was evaluated as a toner in the same manner as in Example 1. The results are shown in Table 1. In Example 1, evaluation as a toner was performed in the same manner as in Example 1 except that the external additives used were changed to those shown in Table 1. The results are shown in Tables 1 to 4.

[0096]

[Table 1]

[0097]

[Table 2]

[0098]

[Table 3]

[0099]

[Table 4]

[0100]

[Table 5]

[0101]

The polymerized toner of the present invention exhibits good image quality and stable durability in a cleaning system simultaneously with development.

[Brief description of the drawings]

FIG. 1 shows a conventional image forming apparatus.

FIG. 2 is a diagram illustrating one embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

 1. Photoconductor 2. Cleaning device 2a Cleaning blade 3. Charging roller 4. Laser beam irradiation device 5. Developing device 6. Transfer roller 7. Transfer paper 8. Developing roller 9. Developing Roller blade 10. Toner 11. Casing 12. Supply roller

Claims (4)

[Claims] 1. A developing roll carrying a developer charged to the same polarity as an electrostatic latent image on a photoreceptor is arranged in contact with the photoreceptor to develop an exposed area of the photoreceptor and simultaneously expose the photoreceptor to non-exposure. At least a binder resin used in a developing method in which the residual developer adhering to the area is removed by suction to the developing roll side and cleaned, and the rotation direction at the contact portion between the photoconductor and the developing roll is rotated in the same direction. And a colorant, wherein the surface of the polymerized toner is externally added as an external additive by: Diameter 1
Silica A having a thickness of 0 to 50 nm (2) The surface of which is hydrophobized with aminosilane and / or silicone oil to have a particle size of 5 when externally added to the toner.
Silica B having a thickness of more than 0 nm and 200 nm or less (3) A polymerized toner having a conductive metal oxide C 2 having a resistance value of 100 Ωcm or less adhered thereto. 2. The amount of silica A attached to the polymerized toner is 0.1 to 2.0% by weight, the amount of silica B attached is 0.3 to 2.0% by weight, and the conductive metal oxide C is attached. Quantity is 0.1
2. The polymerized toner according to claim 1, wherein the content of the polymerized toner is from 1.0 to 1.0% by weight. 3. The polymerized toner according to claim 1, wherein the conductive metal oxide comprises tin-antimony-doped titanium oxide. 4. The method according to claim 1, wherein the conductive metal oxide is made of antimony-doped tin oxide.
Item 7. The polymerized toner according to item 1.