JP2002323783A - Device for forming image and method for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for forming images so that images with high gradation and high resolution can be obtained. SOLUTION: In the device for forming images equipped with at least a photoreceptor and a toner, the outermost layer of the photoreceptor contains a polysiloxane compound having 1a long-chain hydrocarbon-modified siloxane units and 1b alkoxy-modified siloxane units in the molecule. The toner has 3 to 8 μm volume average particle size Dv and manufactured by a wet polymerization method. This device is used for the method for forming images.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus and an image forming method. More specifically,
The present invention relates to an image forming apparatus and an image forming method using an electrophotographic photosensitive member containing a polysiloxane compound in an outermost layer.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors are generally subjected to repeated electrostatographic cycling operations,
Wear of the exposed layer of the photoreceptor results in gradual degradation of the mechanical and electrical properties of the exposed layer. For example, repeated cycling adversely affects the exposed surface of the outermost layer of the photoreceptor, such as the charge transport layer, charge generation layer, overcoating layer.

For example, when the charge transport layer is the outermost layer,
Reduction of the charge transport layer thickness due to abrasion increases the electric field across the layer, thereby increasing dark decay and reducing the electrophotographic operating life of the imaging member. Attempts to correct wear of the imaging member by increasing the thickness of the charge transport layer have caused a reduction in the electric field, thereby changing the photoelectric performance and also degrading the print finish of the copy,
This requires a rather complicated device to correct the thicker charge transport layer. Furthermore, changes in the thickness of the charge transport layer as the charge transport layer wears will change the electrical properties of the photoreceptor, and consequently the quality of the formed image. To address such problems, many attempts have been made to reduce the friction by including specific fine particles in the outermost layer of the photoreceptor. For example, a method in which metal fine particles are dispersed in the outermost layer (Japanese Patent Application Laid-Open No. 57-154250) JP-A-62-250460, JP-A-63-91667, JP-A-63-118754, and those containing oxide fine particles.
And Japanese Patent Application Laid-Open No. 1-183666) and those containing fine particles of silicone resin (Japanese Patent Application Laid-Open No. 2-1562).
No. 46, Japanese Patent Application No. 5-224438, etc.). Japanese Patent Application Laid-Open No. 10-171135 discloses an electrophotographic photoreceptor in which a photosensitive layer is added with a silicone oil compatible with the material constituting the photosensitive layer in an amount exceeding the limit of compatibility with the material constituting the photosensitive layer. Is disclosed. Further, Japanese Patent Application Laid-Open No. 10-268545 discloses an electrophotographic photosensitive member containing a specific polysiloxane compound in the outermost layer.

[0004] However, according to the above prior art,
The effect of reducing friction on the outermost layer surface of the photoreceptor is not always sufficient, and further improvement is expected to solve the above problems. In recent years, the demand for high-definition images has become stronger.
Japanese Patent No. 37678 discloses an invention relating to an image forming method using a specific charge generating agent and a small particle size toner. However, in practice, the above-mentioned problem is not always sufficiently solved if the toner has a small particle size. Because
Even if the electrostatic latent image on the photoreceptor is high-definition, toner rides on this electrostatic latent image, and the image on the photoreceptor remains faithful even when it is finally transferred to paper. Otherwise, the resulting image will not be high definition. Further, the toner having a high degree of circularity may not be removed from the photoreceptor even by a photoreceptor cleaning device such as blade cleaning, and the transferability of the pulverized toner tends to be poor. Also, when the wax content in the toner is increased to improve the fixing performance, the filming on the photoreceptor by the wax tends to occur,
In some cases, high-definition image formation was hindered.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art. That is, an object of the present invention is that the transferability of the toner is good, the filming of the wax on the photoconductor is small,
It is another object of the present invention to provide an image forming apparatus and an image forming method capable of obtaining an image having excellent fine line reproducibility and gradation.

[0006]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems, and as a result, have found that the above problems can be solved by a combination of a specific photoreceptor and toner, and have reached the present invention. That is, the gist of the present invention is to provide an image forming apparatus including at least a photoconductor and a toner.
The outermost layer of the photoreceptor contains a polysiloxane compound having a structural unit represented by the following general formula (1a) and a structural unit represented by the following general formula (1b) in a molecule, and the toner comprises:
An image forming apparatus having a volume average particle diameter (Dv) of 3 to 8 μm and manufactured by a wet polymerization method.

[0007]

Embedded image

(In the general formulas (1a) and (1b), R ¹ and R ³ each independently represent a hydrocarbon group which may have a substituent, and R ² represents a substituted or unsubstituted hydrocarbon group having 3 or more carbon atoms. Represents a hydrocarbon group which may have a group, R ⁴ represents a divalent hydrocarbon group having 1 to 3 carbon atoms, and R ⁵ may have a substituent having 3 or more carbon atoms. Further, another gist of the present invention is to provide an image forming method using at least a photoreceptor, an exposure device, and an image forming apparatus including a toner, wherein the outermost layer of the photoreceptor has the general formula (1a)
A polysiloxane compound having in its molecule a structural unit represented by and a structural unit represented by the general formula (1b),
The photoreceptor is subjected to digital image exposure by the exposing device to form an electrostatic latent image on the photoreceptor, and in the development of the electrostatic latent image, a volume average particle diameter manufactured by a wet polymerization method ( Dv), which uses a toner having a particle size of 3 to 8 μm.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an outline of an image forming method and an image forming apparatus used in the present invention will be described for an electrophotographic recording apparatus using a non-magnetic one-component toner which is an example of a full-color image forming method. However, the present invention is not limited to this example. FIG. 1 is a schematic view of a main configuration of an embodiment of an electrophotographic recording apparatus used in the present invention, and includes a photoconductor 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6, and Fixing device 7
have.

The photosensitive member 1 is formed of a conductor such as aluminum, for example, and has a photosensitive layer formed by coating a photosensitive conductive material on the outer peripheral surface. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the photoreceptor 1, respectively.

The charging device 2 uniformly charges the surface of the photoconductor 1 to a predetermined potential. The exposure device 3 applies L to the photosensitive surface of the photoconductor 1.
This is to form an electrostatic latent image on the photosensitive surface of the photoconductor 1 by performing exposure with ED, laser light, or the like.

The developing device 4 comprises an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45.
The toner T is stored therein. If necessary, the developing device may be provided with a replenishing device (not shown) for replenishing the toner, and the replenishing device can replenish the toner from a container such as a bottle or a cartridge.

The supply roller 43 is made of a conductive sponge or the like, and is in contact with the developing roller 44. The developing roller 44 is disposed between the photoconductor 1 and the supply roller 43. The developing roller 44 is in contact with the photoconductor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism. The supply roller 43 carries the stored toner and supplies it to the developing roller 44. Developing roller 44
Carries the toner supplied by the supply roller 43 and contacts the surface of the photoconductor 1.

The developing roller 44 is made of iron, stainless steel,
It is made of a metal roll of aluminum, nickel, or the like, or a resin roll in which a metal roll is coated with a silicon resin, a urethane resin, a fluororesin, or the like. The surface of the developing roll is
If necessary, the surface may be smoothed or roughened.

The regulating member 45 is formed of a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or the like, or a metal blade coated with a resin. The regulating member 45 contacts the developing roller 44,
A predetermined force is applied to the developing roller 44 side by a spring or the like (a general blade linear pressure is 5 to 500 g / cm), and a function of imparting charge to the toner by frictional charging with the toner as necessary is provided. You may.

The agitator 42 is rotated by a rotary drive mechanism, and agitates the toner and conveys the toner to the supply roller 43 side. A plurality of agitators may be provided with different blade shapes, sizes, and the like.

The transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like, which are arranged to face the photosensitive member 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charged potential of the toner, and transfers the toner image formed on the photoconductor 1 to the recording paper P.

The cleaning device 6 comprises a cleaning member such as a urethane blade or a fur brush.
The cleaning device removes the residual toner attached to the photoreceptor 1 and collects the residual toner.

The fixing device 7 comprises an upper fixing member 71 and a lower fixing member 72, and has a heating device 73 inside the upper or lower fixing member. As the fixing member, a known heat fixing member such as a fixing roll in which a metal tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet can be used. Further, a releasing agent such as silicone oil may be supplied to the fixing member to improve the releasing property. Further, a mechanism for forcibly applying pressure to the upper fixing member and the lower fixing member by a spring or the like may be employed.

When the toner transferred onto the paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state, cooled after passing through, and recorded. The toner is fixed on the paper P.

In the electrophotographic recording apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoconductor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. continue,
The charged photosensitive surface of the photoreceptor 1 is exposed by the exposure device 3 in accordance with an image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, the developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photosensitive member 1.

The developing device 4 thins the toner supplied by the supply roller 43 by the developing blade 45, and also has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1 and a negative polarity). It is charged, carried on the developing roller 44, transported, and brought into contact with the surface of the photoconductor 1.

From the developing roller 44, a toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive member 1 by a so-called reversal developing method. Then, the toner image is transferred to the sheet P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoconductor 1 without being transferred is removed by the cleaning device 6. The final image is obtained by passing the toner on the recording paper P through the fixing device 7 and thermally fixing the toner.

Next, the toner used in the present invention will be described. The toner used in the present invention contains at least a binder resin and a colorant, and may contain a charge controlling agent, a wax, and other additives as necessary. The toner used in the present invention is manufactured by a wet polymerization method such as an emulsion polymerization / aggregation method and a suspension polymerization method. Among them, the emulsion polymerization / aggregation method is preferable in order to achieve the suitable particle size distribution of the present invention. The emulsion polymerization / aggregation method has an advantage that the circularity of the toner can be appropriately controlled.

The binder resin used for the toner can be selected from a wide range including conventionally known ones. Preferably, a styrene-based polymer such as a styrene-acrylate copolymer, a styrene-methacrylate copolymer, or an acrylic copolymer of these resins, a saturated or unsaturated polyester-based polymer, and an epoxy-based polymer are exemplified. be able to. Further, the binder resin is not limited to being used alone, and two or more kinds may be used in combination. When a toner is manufactured by an emulsion polymerization / aggregation method, at least styrenes are used as a copolymer component, and at least one of acrylic acid, methacrylic acid, an alkyl ester of acrylic acid or methacrylic acid is used as a copolymer component. It is preferably used.

The colorant may be any of an inorganic or organic pigment, an organic dye, or a combination thereof. Specific examples of these include carbon black,
Aniline blue, phthalocyanine blue, phthalocyanine green, hansa yellow, rhodamine dye, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo dye,
Any known dyes and pigments such as disazo and condensed azo dyes can be used alone or in combination. In the case of a full-color toner, it is preferable to use benzidine yellow, a monoazo-based, condensed azo-based dye and pigment as yellow, quinacridone and monoazo-based dye and pigment as magenta, and phthalocyanine blue as cyan, respectively.

Of these, cyan colorants include C.I.
I. Pigment Blue 15: 3, and C.I. I. Pigment yellow 74, C.I. I. Pigment Yellow 93 and magenta colorants include C.I. I. Pigment Red 238, C.I. I. Pigment Red 26
9, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 48: 2, C.I. I. Pigment Red 12
2 is preferably used. The amount of the colorant added is preferably in the range of 2 to 25 parts by weight based on 100 parts by weight of the binder resin.

The toner used in the present invention has a charge amount,
For imparting charge stability, a charge control agent may be added.
As the charge control agent, a conventionally known compound is used.
Examples thereof include metal complexes of hydroxycarboxylic acids, metal complexes of azo compounds, naphthol compounds, metal compounds of naphthol compounds, nigrosine dyes, quaternary ammonium salts, and mixtures thereof. The addition amount of the charge control agent is preferably in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the binder resin.

It is preferable to add a wax to the toner used in the present invention in order to impart releasability from a fixing roll. Any wax can be used as long as it has a releasing property. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymerized polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanic acid ester, and stearyl stearate; Vegetable waxes such as castor oil and carnauba wax; ketones having a long-chain alkyl group such as distearyl ketone; silicones having an alkyl group; higher fatty acids such as stearic acid; long-chain aliphatic alcohols such as eicosanol; glycerin and pentaerythritol Carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols and long-chain fatty acids; higher fatty acid amides such as oleic amide and stearic acid amide; and low molecular weight polyesters.

In order to improve the fixability among these waxes, the melting point of the wax is preferably 30 ° C. or more,
0 ° C. or higher is more preferable, and 50 ° C. or higher is particularly preferable.
Further, the temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and particularly preferably 80 ° C. or lower. If the melting point is too low, the wax is likely to be exposed on the surface after fixing and sticky,
If the melting point is too high, the fixability at low temperatures is poor. Further, as the compound type of the wax, a higher fatty acid ester wax is preferable. Specific examples of the higher fatty acid ester wax include, for example, behenyl behenate, stearyl stearate, stearic acid ester of pentaerythritol, glyceride montanic acid, etc. Esters are preferred. The alcohol component constituting the ester preferably has 10 to 30 carbon atoms in the case of a monohydric alcohol, and preferably has 3 to 10 carbon atoms in the case of a polyhydric alcohol.

The above waxes may be used alone or as a mixture. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature at which the toner is fixed. The amount of the wax used in the toner is usually 0.1 to 4
0%, preferably 1-40%, more preferably 5-35
%, Particularly preferably 7 to 30%.

Next, the production of a toner by a wet polymerization method will be described. In the emulsion polymerization / aggregation method, a colorant dispersion, a charge control agent dispersion, a wax dispersion, and the like are mixed with a dispersion of polymer primary particles, and these are aggregated by appropriately controlling the temperature, salt concentration, pH, and the like. To produce toner.

The emulsifier used in the wet polymerization method is selected from a cationic surfactant, an anionic surfactant and a nonionic surfactant. Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and the like. Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium lauryl sulfate and the like. Further, specific examples of the nonionic surfactant include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, and monodecanoyl. And sucrose. Among these surfactants, alkali metal salts of linear alkylbenzene sulfonic acids are preferred.

In the suspension polymerization method, a colorant,
The charge control agent, wax and the like are mixed and subjected to a dispersion treatment using a disperser such as a disperser, and the monomer composition after the dispersion treatment is dispersed in a water-miscible medium using a suitable stirrer. After granulating to a diameter, the polymerizable monomer is polymerized to produce a toner.

When a suspension stabilizer is used, it is preferred to select a neutral or alkaline water-soluble one which can be easily removed by acid washing of the toner after polymerization.
Further, it is preferable to select a toner capable of obtaining a toner having a narrow particle size distribution. As a suspension stabilizer satisfying these,
Examples include calcium phosphate, tricalcium phosphate, magnesium phosphate, calcium hydroxide, magnesium hydroxide and the like. Each can be used alone or in combination of two or more. These suspension stabilizers are usually used in an amount of 1 to 10 based on 100 parts by weight of the radical polymerizable monomer.
Parts by weight can be used.

As the polymerization initiator used in the wet polymerization method, known polymerization initiators can be used alone or in combination of two or more. For example, potassium persulfate, 2,
2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, lauroyl peroxide, a redox initiator, and the like can be used. Of these,
In the emulsion polymerization / aggregation method, a redox initiator is preferable,
In the suspension polymerization method, an azo initiator is preferred. After the toner is manufactured by the above method, a toner having a capsule structure may be obtained by adding a polymer emulsion, a colorant dispersion, a charge control agent dispersion, a wax dispersion, and the like, and coating the toner surface.

Next, the emulsion polymerization / aggregation method, which is a preferred method for producing the toner of the present invention, will be described in more detail. When a toner is produced by an emulsion polymerization / aggregation method, it usually has a polymerization step, a mixing step, an aggregation step, an aging step, and a washing / drying step. That is, a dispersion containing primary particles of a polymer obtained by emulsion polymerization is mixed with a dispersion of each particle such as a colorant, a charge control agent, and wax, and the primary particles in the dispersion are aggregated to obtain a volume average particle size. A particle aggregate having a diameter of about 3 to 8 μm is formed, and if necessary, resin fine particles and the like are adhered to the particle aggregate, and if necessary, the particle aggregate or the particle aggregate to which the resin fine particles are adhered is fused, and thus obtained. The resulting toner particles are washed and dried to obtain toner particles of the product.

Polymer Primary Particles The polymer primary particles used in the emulsion polymerization / aggregation method preferably have a glass transition temperature (Tg) of 40 to 80 ° C.
And the average particle size is usually from 0.02 to 3 μm. The polymer primary particles are obtained by emulsion polymerization of a monomer.

In the emulsion polymerization, a monomer having a Bronsted acidic group (hereinafter sometimes simply referred to as an acidic group) or a Bronsted basic group (hereinafter sometimes simply referred to as a basic group) is successively used. The polymerization proceeds by adding a monomer and a monomer having neither a Bronsted acidic group nor a Bronsted basic group (hereinafter, sometimes referred to as other monomers). At this time, the monomers may be added separately, or a plurality of monomers may be mixed in advance and then added. Further, the monomer composition can be changed during the addition of the monomer. Further, the monomer may be added as it is, or may be added as an emulsified liquid which is previously mixed and adjusted with water or an emulsifier. As the emulsifier, one or a combination of two or more of the above surfactants is selected.

Examples of the monomer having a Bronsted acidic group include acrylic acid, methacrylic acid, maleic acid,
Examples thereof include monomers having a carboxyl group such as fumaric acid and cinnamic acid, monomers having a sulfonic acid group such as sulfonated styrene, and monomers having a sulfonamide group such as vinylbenzenesulfonamide.

Examples of the monomer having a Brönsted basic group include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocyclic monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, and diethylamino. (Meth) acrylic acid esters having an amino group such as ethyl methacrylate;

The monomer having an acidic group and the monomer having a basic group may each be present as a salt with a counter ion. The blending ratio of the monomer having a Bronsted acidic group or a Bronsted basic group in the monomer mixture constituting the polymer primary particles is preferably 0.05% by weight or more, more preferably 1% by weight or more. And it is preferably at most 10% by weight, more preferably at most 5% by weight. Among monomers having a Bronsted acidic group or a Bronsted basic group, acrylic acid or methacrylic acid is particularly preferred.

Other comonomers include styrene,
Methyl styrene, chlorostyrene, dichlorostyrene,
pt-butylstyrene, pn-butylstyrene, p
-Styrenes such as n-nonylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl (Meth) acrylates such as propyl acrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxyethyl methacrylate, ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropyl Acrylamide, N, N-dibutylacrylamide and acrylamide can be mentioned. Among them, styrene, butyl acrylate and the like are particularly preferred.

Further, when a cross-linking resin is used for the polymer primary particles, a polyfunctional monomer having radical polymerizability is used as a cross-linking agent shared with the above-mentioned monomers, for example, divinylbenzene, hexanediol diacrylate, Examples include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, diallyl phthalate, and the like. It is also possible to use a monomer having a reactive group in the pendant group, for example, glycidyl methacrylate, methylolacrylamide, acrolein and the like.

Preferably, a radically polymerizable bifunctional monomer is used, and more preferably, divinylbenzene and hexanediol diacrylate are used. The blending ratio of such a polyfunctional monomer in the monomer mixture is preferably at least 0.005% by weight, more preferably at least 0.1% by weight, particularly preferably at least 0.3% by weight. Preferably 5% by weight or less, more preferably 3% by weight or less,
It is particularly preferably at most 1% by weight.

These monomers may be used alone or as a mixture. In this case, the polymer has a glass transition temperature of 40.
~ 80 ° C is preferred. Glass transition temperature 80
If the temperature exceeds 100 ° C., the fixing temperature may become too high, or the OHP transparency may deteriorate. On the other hand, if the glass transition temperature of the polymer is lower than 40 ° C., the storage stability of the toner may deteriorate. is there.

The polymerization initiator may be added to the polymerization system at any time before, simultaneously with, or after the addition of the monomer, and these addition methods may be combined as necessary. In the emulsion polymerization, a known chain transfer agent can be used if necessary. Specific examples of such a chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, Examples thereof include carbon chloride and trichlorobromomethane. The chain transfer agent may be used alone or in combination of two or more kinds, and is usually used in an amount of 0 to 5% by weight based on the polymerizable monomer. In the emulsion polymerization, the above monomers are mixed with water and polymerized in the presence of a polymerization initiator. The polymerization temperature is usually 50 to 150 ° C, preferably 60 to 120 ° C, more preferably 70 to 100 ° C.
° C.

The volume average particle size of the thus obtained polymer primary particles is usually in the range of 0.02 to 3 μm, preferably 0.05 to 3 μm, more preferably 0.1 to 2 μm.
And particularly preferably 0.1 to 1 μm. In addition,
The average particle size can be measured using, for example, UPA. When the particle size is smaller than 0.02 μm, it is difficult to control the agglomeration rate, which is not preferable. On the other hand, if it is larger than 3 μm, the particle size of the toner obtained by aggregation tends to be large, which is unsuitable for producing a toner having a particle size of 3 to 8 μm.

○ Colorant In the emulsion polymerization / aggregation method, a dispersion of primary polymer particles and colorant particles are mixed to form a mixed dispersion, which is then aggregated to form a particle aggregate. The emulsion is preferably emulsified in water in the presence of an emulsifier (the above-described surfactant) and used in the form of an emulsion. The volume average particle size of the colorant particles is preferably from 0.01 to 3 μm. The amount of the colorant used is usually 1-2 parts per 100 parts by weight of the polymer primary particles.
It is 5 parts by weight, preferably 3 to 20 parts by weight.

○ Wax In the emulsion polymerization / aggregation method, it is preferable to use a wax which has been dispersed in the presence of an emulsifier (the above-mentioned surfactant) and emulsified into a wax fine particle dispersion. The wax is present in the agglomeration step. Examples of the wax include a case where the wax fine particle dispersion is coagulated with the polymer primary particles and the colorant particles, and a case where the wax is obtained by subjecting the monomer to seed emulsion polymerization in the presence of the wax fine particle dispersion. In some cases, a polymer primary particle containing the above is prepared and this and the colorant particles are aggregated. Of these, in order to uniformly disperse the wax in the toner, it is preferable that the wax fine particle dispersion is present at the time of producing the above-mentioned polymer primary particles, that is, at the time of polymerizing the monomer.

The average particle size of the wax fine particles is from 0.01 to
3 μm is preferred, more preferably 0.1 to 2 μm,
In particular, those having a size of 0.3 to 1.5 μm are preferably used. The average particle diameter can be measured using, for example, LA-500 manufactured by Horiba. When the average particle size of the wax emulsion is larger than 3 μm, it tends to be difficult to control the particle size during aggregation, and when the average particle size of the emulsion is smaller than 0.01 μm, a dispersion is prepared. Difficult to do.

○ Charge control agent In the emulsion polymerization / aggregation method, a charge control agent is used as a seed simultaneously with wax when obtaining polymer primary particles, or a charge control agent is used as a monomer or wax when obtaining primary particles of a polymer. Used or dissolved in or dispersed in the polymer, the primary particles of the charge control agent and the primary particles of the colorant are agglomerated together with the colorant to form a particle aggregate, or the primary particles of the polymer and the colorant are agglomerated, almost as a toner. After the particles have an appropriate particle size, primary particles of the charge control agent can be added to cause aggregation. In this case, the charge control agent is also dispersed in water using an emulsifier (the above-mentioned surfactant), and the average particle size is 0.01 to 3
It is preferably used as a μm emulsion (primary particles of a charge control agent).

In the aggregating step of the above-mentioned production method, the above-mentioned particles of the blending components such as the polymer primary particles, the colorant particles, the charge control agent, and the wax, if necessary, are mixed simultaneously or sequentially. A dispersion liquid of each component, that is, a polymer primary particle dispersion liquid, a colorant particle dispersion liquid, a charge control agent dispersion liquid, and a wax fine particle dispersion liquid are prepared beforehand, and these are mixed. To obtain a mixed dispersion. Further, it is preferable that the wax is contained in the toner by using polymer primary particles encapsulated in the polymer primary particles, that is, polymer primary particles obtained by emulsion polymerization using the wax as a seed. In this case, the polymer primary particles are used. The wax encapsulated in the, can be used in combination with wax particles not encapsulated, more preferably,
Substantially all of the wax is used in a form encapsulated in the primary polymer particles.

Aggregation step The above-mentioned mixed dispersion of particles is aggregated in the aggregation step to form a particle aggregate. In this aggregation step, 1) a method of performing aggregation by heating and 2) adding an electrolyte There is a method of performing aggregation.

When performing aggregation by heating, the aggregation temperature is specifically in the temperature range of 50 ° C. to Tg (where Tg is the glass transition temperature of the primary polymer particles) and Tg−10.
C. to Tg-5 C. are preferred. Within the above temperature range, the toner can be aggregated to a preferable toner particle size without using an electrolyte. When performing aggregation by heating,
When the aging step is performed subsequent to the aggregating step, the aggregating step and the aging step are performed continuously, and the boundary may be ambiguous, but the temperature is maintained in a temperature range of Tg-20 ° C to Tg for at least 30 minutes. If there is a step to perform, this is regarded as an aggregation step. The aggregation temperature is preferably maintained at a predetermined temperature for at least 30 minutes to obtain toner particles having a desired particle size. The temperature may be raised at a constant rate up to a predetermined temperature, or may be raised stepwise. The retention time is T
The temperature is preferably from 30 minutes to 8 hours, more preferably from 1 hour to 4 hours, in the range of g-20 ° C to Tg. By doing so, a toner having a small particle size and a sharp particle size distribution can be obtained.

Further, an electrolyte is added to the mixed dispersion to coagulate.
The electrolyte used when performing the reaction is either an organic salt or an inorganic salt.
, But is preferably monovalent or divalent or more polyvalent
Metal salts are preferably used. Specifically, NaCl,
KCl, LiCl, Na_TwoSO_Four, K_TwoSO_Four, Li_TwoS
O_Four, MgCl_Two, CaCl_Two, MgSO_Four, CaSO_Four,
ZnSO_Four, Al_Two(SO_Four)_Three, Fe_Two(SO_Four)_Three, CH_Three
COONa, C₆H_FiveSO _ThreeNa and the like.

The amount of the electrolyte to be added varies depending on the type of the electrolyte, but usually 0.05 to 25 parts by weight based on 100 parts by weight of the solid component of the mixed dispersion. Preferably 0.1 to 15 parts by weight, more preferably 0.1 to 10 parts by weight
Parts by weight. When the amount of the electrolyte added is significantly less than the above range, the progress of the agglutination reaction is slowed down, fine powder of 1 μm or less remains even after the agglutination reaction, or the average particle diameter of the obtained particle aggregate becomes 3 μm or less. Tends to cause problems. Further, when the amount of the electrolyte added is significantly larger than the above range, the aggregation tends to be rapid and difficult to control, and coarse particles of 25 μm or more are mixed in the obtained particle aggregate, or the shape of the aggregate is distorted. It tends to cause problems such as irregular shapes. In addition, when performing aggregation by adding an electrolyte to the mixed dispersion, the aggregation temperature is preferably in a temperature range of 5 ° C. to Tg.

○ Other Components Next, according to the present invention, the surface of the particle aggregate after the above-mentioned aggregation treatment is coated (adhered or fixed) with resin fine particles as necessary to form toner particles. preferable. When the above-described charge control agent is added after the aggregation treatment, resin fine particles may be added after the charge control agent is added to the dispersion containing the particle aggregate.

The resin fine particles are dispersed in water or a liquid mainly composed of water with an emulsifier (the above-mentioned surfactant) and used as an emulsion. The resin fine particles used for the outermost layer of the toner do not contain wax. Is preferred. As the resin fine particles, preferably, the volume average particle size is from 0.02 to
Those having a size of 3 μm, more preferably 0.05 to 1.5 μm, obtained by polymerizing a monomer similar to the monomer used for the above-mentioned polymer primary particles can be used. When the toner is formed by coating the particle aggregate with resin fine particles, the resin used for the resin fine particles is preferably cross-linked.

Aging Step In the emulsion polymerization / aggregation method, Tg + 20 ° C. is used to increase the stability of the particle aggregate (toner particles) obtained by aggregation.
It is preferable to add a ripening step of causing fusion between aggregated particles in the range of Tg + 80 ° C. (where Tg is the glass transition temperature of the primary polymer particles). In the aging step, it is preferable to maintain the temperature in the above-mentioned temperature range for 1 hour or more. By adding the aging step, the shape of the toner particles can be made nearly spherical, and the shape can be controlled. This aging step is usually performed for 1 hour to 24 hours, preferably 1 hour to 10 hours. Although the particle aggregate before the aging step is considered to be an aggregate due to electrostatic or other physical aggregation of the primary particles, after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. And
Preferably it is substantially spherical. In addition, according to such a method for producing a toner, various shapes such as a grape type in which primary particles are aggregated, a potato type in which fusion has progressed halfway, a spherical shape in which fusion has further progressed, and the like according to purposes. A toner can be manufactured.

Washing / Drying Step The particle aggregate obtained through each of the above steps is subjected to solid-liquid separation according to a known method, and the particle aggregate is recovered, and then, if necessary, washed. Thereafter, by drying, desired toner particles can be obtained. In this manner, a toner having a relatively small volume average particle diameter of 3 to 8 μm can be manufactured. Moreover, the toner thus obtained has a sharp particle size distribution and is suitable as a toner for developing an electrostatic image for achieving high image quality and high speed.

A known external additive may be added to the toner used in the present invention to control fluidity and developability.
As the external additive, various inorganic oxide particles such as silica, alumina and titania (which may be subjected to a hydrophobic treatment if necessary), vinyl polymer particles and the like can be used. The amount of the external additive is preferably in the range of 0.05 to 5 parts by weight based on the toner particles.

The toner used in the present invention can be applied to a two-component developer, a magnetic one-component developer such as a magnetite-containing toner, and a non-magnetic one-component developer. When used as a two-component developer, known carriers such as iron powder-based, ferrite-based, and magnetite-based carriers or resin coatings on their surfaces are used as carriers for forming the developer by mixing with the toner. Or a magnetic resin carrier can be used.

As the coating resin for the carrier, generally known styrene resins, acrylic resins, styrene-acryl copolymer resins, silicone resins, modified silicone resins, fluorine resins and the like can be used. It is not limited. The average particle size of the carrier is not particularly limited, but preferably has an average particle size of 10 to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by weight based on 1 part by weight of the toner.

A method for measuring the particle size of the toner is as follows.
A commercially available particle size measuring apparatus can be used, but typically, a precision particle size distribution measuring apparatus manufactured by Beckman Coulter KK Coulter Counter Multisizer II
Is used. The toner used in the present invention has a volume average particle size (Dv) of 3 to 8 μm. Volume average particle size is 4 ~
8 μm is preferred, and 4-7 μm is more preferred. If the volume average particle diameter is too large, it is not suitable for forming a high-resolution image, and if it is too small, handling as a powder becomes difficult.

As the circularity of the toner, a toner having a 50% circularity of 0.9 to 1 is preferable. However, 50% circularity is typically measured by measuring the toner with a flow particle image analyzer FPIA-2000 manufactured by Sysmex Corporation, and the formula: circularity = perimeter of a circle having the same area as the projected area of the particle / particle The perimeter of the projected image corresponds to the cumulative particle size distribution value at 50% of the value obtained from this. More preferably, the 50% circularity is 0.92 to 1, especially when used in an image forming apparatus provided with a device (cleaning device) for removing the toner on the photoreceptor. A value of 0.92 to 0.96, which facilitates scraping by the apparatus, is particularly preferable. In the case of designing an image forming apparatus without a cleaning device, for example, an apparatus without a cleaning device by increasing the transferability of toner, the 50% circularity indicates the contact point between the toner and the photoconductor. Particularly preferred is a value of 0.96 to 0.995 which can be minimized. Whether or not the image forming apparatus has a cleaning device is appropriately selected depending on the durability of the photoconductor and other conditions.

In order to achieve a suitable particle size distribution of the toner of the present invention, an emulsion polymerization / aggregation method is particularly preferred. A toner having a sharp particle size distribution is advantageous for forming a high-definition image by uniformly distributing the colorant and the charge control agent and the like, thereby making the chargeability uniform. Specifically, in the image forming method and apparatus of the present invention, the volume average particle diameter (D
v) and the number average particle diameter (Dn) are 1.0 ≦ Dv
Those satisfying /Dn≦1.3 are preferably used. Dv
The value of / Dn is more preferably 1.25 or less,
1.20 or less is more preferable. Further, the lower limit of Dv / Dn is 1, which means that all particle diameters are equal, which is difficult in production. Therefore, it is preferably 1.03 or more, more preferably 1.05 or more.

It is preferable that the toner has few fine particles (fine powder). When the number of fine particles is small, the fluidity of the toner is improved, and the colorant, the charge control agent, and the like are uniformly distributed, and the chargeability is likely to be uniform. For measuring fine particles, for example, a flow particle image analyzer FPIA-2000 manufactured by Sysmex Corporation is preferably used. In the present invention, 0.6 to 2.1 by a flow type particle image analyzer.
It is preferable to use a toner whose measured value (number) of 2 μm particles is 15% or less of the total number of particles. This means that the fine particles are less than a certain amount,
2. The number of 12 μm particles is more preferably 10% or less,
Particularly preferred is 5% or less. The lower limit of the fine particles is not particularly limited, and it is most preferable that the fine particles do not exist at all. However, it is difficult to produce the fine particles, and usually 0.5% or more, preferably 1% or more.
% Or more.

Next, the photosensitive member used in the present invention will be described. The photoreceptor used in the present invention has at least a photosensitive layer on a conductive support, and the photosensitive layer is preferably a laminated photoreceptor in which a charge generation layer and a charge transport layer are laminated. The charge generation layer and the charge transport layer usually have a configuration in which the charge transport layer is laminated on the charge generation layer,
The reverse configuration may be used. Further, in addition to the photosensitive layer, an intermediate layer such as an adhesive layer and a blocking layer, and a layer for improving electric characteristics and mechanical characteristics such as a protective layer may be provided. As the conductive support, any of those used in known electrophotographic photoreceptors can be used.

As the conductive support, any of those used for known electrophotographic photosensitive members can be used. Specific examples include metal drums and sheets of aluminum, stainless steel, copper, and the like, and laminates and vapor-deposits of these metal foils. Further, plastic films, plastic drums, paper, paper tubes, and the like, which have been subjected to a conductive treatment by applying a conductive substance such as metal powder, carbon black, copper iodide, and a polymer electrolyte together with a suitable binder, may be mentioned. Further, a plastic sheet or drum containing a conductive substance such as a metal powder, carbon black, or carbon fiber to become conductive may be used. Further, plastic films and belts which have been subjected to conductive treatment with a conductive metal oxide such as tin oxide or indium oxide may be used. When used in a small-sized, high-speed electrophotographic apparatus, the conductive support is preferably in the form of a drum.
It is 0 to 40 mm, preferably 13 to 35 mm, and more preferably 16 to 30 mm. Further, in the case of a small-sized device, it is particularly preferable that the length is 13 to 25 mm. The above-described small-diameter drum is particularly advantageous in the case of a color electrophotographic apparatus, in which a photoconductor is used for each of the four color toners of cyan, magenta, yellow, and black.

A blocking layer is provided between the conductive support and the charge generation layer, if necessary. As the blocking layer, an alumite layer or an undercoat layer (also referred to as an intermediate layer) made of a resin or an undercoat layer may be used. Those used in combination are used.

When the undercoat layer is provided on the conductive support, the binder resin may be polyvinyl methyl ether, poly-N-vinyl imidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein. Resin materials such as gelatin, polyethylene, polyester, phenolic resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, polyvinylpyrrolidone, polyvinylpyridine, polyurethane, polyglutamic acid, polyacrylic acid, and polyamide resin can be used.

The charge generation layer contains at least a binder resin and a charge generation agent. As the charge generating agent, known ones are used, but oxytitanium phthalocyanine is preferably used for application to a small, high-speed, high-sensitivity device. Examples of the binder resin used for the charge generation layer include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylates, methacrylates, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, and polyester. , Polyamide, polyurethane, cellulose ester, cellulose ether, phenoxy resin,
Silicon resin, epoxy resin and the like can be mentioned. The ratio between the oxytitanium phthalocyanine and the binder polymer is not particularly limited, but is generally 5 to 500 parts by weight, based on 100 parts by weight of the oxytitanium phthalocyanine.
Preferably, 20 to 300 parts by weight of a binder polymer is used.

The thickness of the charge generation layer is 0.05 to 5 μm,
Preferably it is 0.1 to 2 μm. The charge transport layer into which charge carriers are injected from the charge generation layer contains a charge transport agent having high carrier injection efficiency and transfer efficiency.

Next, the photoreceptor used in the present invention contains a polysiloxane compound having a specific structure in the outermost layer. In a photoreceptor having a protective layer on the photosensitive layer, the outermost layer is a protective layer, and in a photoreceptor having no protective layer in the photosensitive layer, the outermost layer is a photosensitive layer. Furthermore, when the photosensitive layer is the outermost layer and the photosensitive layer is a laminate of a charge generation layer and a charge transport layer, the charge transport layer is usually the outermost layer. Hereinafter, as a preferred embodiment of the present invention, a charge transport layer containing a polysiloxane compound, for example, in the case where there is no protective layer on the photosensitive layer and the photosensitive layer is a stacked type of a charge generation layer and a charge transport layer Will be described as an example.

The charge transport layer comprises at least a binder, a structural unit represented by the following general formula (1a) and a general formula (1
b) a polysiloxane compound having both structural units in the molecule together with a charge transport agent,
If necessary, various additives such as an antioxidant, a sensitizer, a plasticizer, a fluidity-imparting agent, and a crosslinking agent may be contained.

[0077]

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(In the general formulas (1a) and (1b), R ¹ and R ³ each independently represent a hydrocarbon group which may have a substituent, and R ² is a substituted or unsubstituted hydrocarbon group having 3 or more carbon atoms. Represents a hydrocarbon group which may have a group, R ⁴ represents a divalent hydrocarbon group having 1 to 3 carbon atoms, and R ⁵ may have a substituent having 3 or more carbon atoms. R ¹ and R ³ each independently represent a hydrocarbon group which may have a substituent. The hydrocarbon group is preferably an alkyl group, and is preferably an alkyl group having 1 to 30 carbon atoms. Groups are more preferred.
If the number of carbon atoms exceeds 30, the compatibility with the binder tends to decrease.

R ² represents a hydrocarbon group having 3 or more carbon atoms and which may have a substituent. As the hydrocarbon group, an alkyl group having 5 to 30 carbon atoms is preferable, and a hydrocarbon group having 8 to 20 carbon atoms is preferable. Alkyl groups are more preferred. If the carbon number is larger than the above range, the compatibility with the binder tends to decrease, and if it is smaller than the above range, the effect of reducing the friction of the outermost layer tends to be insufficient.

R ⁴ represents a divalent hydrocarbon group having 1 to 3 carbon atoms, preferably a divalent alkylene group having 1 to 3 carbon atoms, specifically, a methylene group, an ethylene group or a propylene group. A propane-1,3-diyl group. Among them, a methylene group and an ethylene group are more preferred.

R ⁵ represents a hydrocarbon group having 3 or more carbon atoms and which may have a substituent. As the hydrocarbon group, an alkyl group having 3 to 8 carbon atoms is preferable.
Alkyl groups having isopropyl or tertiary butyl units are preferred. Here, the isopropyl unit means that part or all of the alkyl group is an isopropyl [(CH ₃ ) ₂ CH] atomic group.
Specifically, for example, isopropyl group, isobutyl group, 3
-Methylbutyl group, 3-methyl-2-butyl group and the like correspond to an alkyl group having 3 to 8 carbon atoms having an isopropyl unit.

Similarly, a tertiary butyl unit means that part or all of an alkyl group is a tertiary butyl [(CH ₃ ) ₃ C] atomic group. Specifically, for example, a tertiary butyl group, a dimethylpropyl group, a 3,3-dimethyl-2-butyl group and the like correspond to an alkyl group having 3 to 8 carbon atoms having a tertiary butyl unit. Among these, an isopropyl group, an isobutyl group and a tertiary butyl group are particularly preferred.

Preferred substituents on the hydrocarbon group represented by R ¹ , R ² , R ³ and R ⁵ include a halogen atom, an alkoxy group, an alkylthio group, a mercapto group, a cyano group and a nitro group. However, unsubstituted ones are preferred.

In particular, when R ⁵ has an isopropyl unit [(CH ₃ ) ₂ CH] or a tertiary butyl unit [(CH ₃ ) ₃ C], it has an affinity for a binder, especially benzene in the binder resin molecule. Considering the affinity for the ring, at least the isopropyl unit
[(CH ₃ ) ₂ CH] or tertiary butyl unit
[(CH ₃ ) ₃ C] is preferably unsubstituted. Also, R
^The total number of carbon atoms of ² and R ⁵ is preferably 6 to 25, and more preferably 8 to 5 in consideration of compatibility between the compatibility with the binder and the friction reducing effect.
20 is more preferred, and 10-18 is particularly preferred.

The polysiloxane compound used in the present invention may contain structural units other than the structural units represented by the general formulas (1a) and (1b) (hereinafter referred to as other structural units). From the viewpoint of securing the reduction effect,
The proportion of the structural unit represented by the general formula (1a) is preferably at least 1% by number, and more preferably 3%, of all the structural units.
To 90% by number, particularly preferably 10 to 70% by number
It is.

From the viewpoint of ensuring the affinity with the binder resin, the ratio of the structural unit represented by the general formula (1b) is preferably 1% by number or more, more preferably 3 to 3%, of all the structural units. 90% by number, particularly preferably 10%
７０70% by number. The ratio (number ratio) between the structural unit (1a) and the structural unit (1b) is preferably 1: 9 to
9: 1, preferably 1: 4 to 3: 2, more preferably 1: 3.
１1: 1 is particularly preferred.

The ratio of the number of carbon atoms (N _C ) to the number of silicon atoms (N _Si ) in the polysiloxane compound (N _C / N _Si )
Is preferably 4 to 2 as a whole polysiloxane compound.
0, and more preferably 6 to 15. Further, the ratio of the number of oxygen atoms (N _O ) to the number of silicon atoms (N _Si ) (N _O /
N _Si ) is preferably from 1.1 to 2, and more preferably from 1.2 to 1.8. When the polysiloxane compound used in the present invention contains another structural unit, the other structural unit is preferably a dialkylsilyloxy structural unit, and more preferably a dimethylsilyloxy structural unit.

The terminal of the polysiloxane compound is preferably a trialkylsilyl group, more preferably a trimethylsilyl group. The content of the polysiloxane compound is 0.005 to 10% by weight based on the total solid content of the outermost layer.
Is preferable, and 0.01 to 1% is more preferable.

If the content is significantly larger than the above range, it is difficult to secure the required hardness of the layer. If the content is extremely small, the effect of reducing friction tends to be insufficient. Further, these polysiloxane compounds can be used in a state of being dispersed or compatible with the binder resin. However, it is preferable to use at least a part of the polysiloxane compound in a compatible state. A binder resin having high solubility is selected. The molecular weight of the polysiloxane compound is usually 100 to 7
0000, preferably 5,000 to 30,000, more preferably 10,000 to 20,000. When the molecular weight is significantly lower than the above range, the effect of the polysiloxane compound as a leveling agent tends to decrease, and when the molecular weight is significantly higher than the above range, the compatibility with the binder resin tends to decrease. .

As the charge transporting agent, a high molecular compound having a side chain of a heterocyclic compound or a condensed polycyclic aromatic compound such as poly-N-vinylcarbazole or polystyrylanthracene, and a low molecular compound such as pyrazoline or imidazole , Oxazole, oxadiazole, triazole,
Heterocyclic compounds such as carbazole, triarylalkane derivatives such as triphenylmethane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N-phenylcarbazole derivatives, stilbene derivatives, and hydrazone compounds. ,
Examples of the compound include an electron-donating group such as a substituted amino group or an alkoxy group, or a compound having a high electron-donating property substituted by an aromatic ring group having these substituents. Of these, compounds represented by the following general formula (2) are preferred.

[0091]

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(In the general formula (2), Ar ¹ represents an optionally substituted benzene ring, an optionally substituted naphthalene ring, or an optionally substituted biphenyl ring; Ar ^{2 to} Ar ⁵ each independently represent an aromatic ring which may have a substituent.) In the general formula (2), Ar ¹ represents a benzene ring which may have a substituent, Represents a naphthalene ring which may have a group, or a biphenyl ring which may have a substituent,
Of these, a biphenyl ring which may have a substituent is preferable. As the substituent, a halogen atom, an alkyl group having 4 or less carbon atoms, an alkoxy group having 3 or less carbon atoms, an alkylthio group having 3 or less carbon atoms, a cyano group, and a nitro group are preferable. Among them, a methyl group, a fluorine atom, and a chlorine atom are preferable. Atoms are more preferred. However, an unsubstituted aromatic ring is most preferred.

Ar ^{2 to} Ar ⁵ each independently represent an aromatic ring which may have a substituent. Examples of the aromatic ring include:
Any of an aromatic hydrocarbon ring and an aromatic heterocyclic ring may be used, and specifically, a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, a pyridine ring, a pyrrole ring, a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, etc. Is mentioned. Of these, a benzene ring, a naphthalene ring and a thiophene ring are preferred. The substituents on these aromatic rings include a halogen atom, an alkyl group having 4 or less carbon atoms, an alkoxy group having 3 or less carbon atoms,
The following alkylthio group, cyano group, nitro group, or substituent represented by the following general formula (3) is preferable.

[0094]

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(In the general formula (3), Ar ⁶ represents a phenyl group which may be substituted with a halogen atom or an alkyl group. R ¹¹ and R ¹² each independently represent a hydrogen atom or a methyl group. And n represents 1, 2 or 3.) Further, a compound having an atomic group represented by Formula (4), Formula (5), Formula (6), Formula (7), or Formula (8) in the molecule. Are also preferably used.

[0096]

Embedded image

[0097]

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The binder used for the charge transport layer is preferably a polymer which has good compatibility with the above charge transport material and does not crystallize or phase separate the charge transport material after forming the coating film. Examples thereof include styrene, vinyl acetate, vinyl chloride, acrylic acid esters, methacrylic acid esters, vinyl alcohol, polymers and copolymers of vinyl compounds such as ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester,
Examples thereof include polysulfone, polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, and epoxy resin.
Of these, polycarbonate resins or polyarylate resins are preferred. As the polyarylate, those containing a structural unit represented by the following general formula (9) are preferable.

[0099]

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(In the general formula (9), Ar¹¹And Ar¹²Is each
Each independently represents a benzene ring which may have a substituent.
X is a divalent aliphatic hydrocarbon which may have a substituent
A benzene ring, which may have a substituent,
May have a naphthalene ring or a substituent
Represents a biphenyl ring which may be substituted. R^{twenty one}And R^{twenty two}Are independent
Aryl group which may have a substituent,
An acyloxy group which may have a substituent
An arylsulfoxy group, R^{twenty one}And R^{twenty two}Are each other
They may be connected to form a ring structure. In the general formula (9), Ar¹¹And Ar¹²Are each independently substituted
Represents a benzene ring which may have a group,
Halogen, cyano, nitro, hydrocarbon
Group, hydrocarbon group substituted with halogen atom, alkoxy
Group, alkoxy group substituted with halogen atom, alkyl
Thio groups are preferred, of which methyl, cyclohexyl,
A sil group, a phenyl group and an allyl group are more preferred. Also,
The benzene ring is also preferably unsubstituted. Also, X
Preferred as a substituent of are a halogen atom, cyano
Group, nitro group, hydrocarbon group, substituted with halogen atom
Substituted with a hydrocarbon group, an alkoxy group, or a halogen atom
An alkoxy group and an alkylthio group.
Nitrogen, chlorine, bromine, methyl, methoxy
Group, trifluoromethyl group, trifluoromethoxy group
More preferred. Also, X is preferably unsubstituted.
No. R^{twenty one}And R^{twenty two}Each independently has a substituent
Good aryl group and optionally substituted acyloxy
Group, an arylsulfoxy group which may have a substituent
Represents, R^{twenty one}And R^{twenty two}Are connected to each other to form a ring structure
But R ^{twenty one}And R^{twenty two}The carbon number of
10 is preferable, and 1 to 8 are more preferable. Also, the substituent
Are halogen, cyano, nitro, alcohol
Xy group, alkoxy group substituted with halogen atom, al
A quinthio group is preferred, and an unsubstituted one is also preferred.

The amount of the binder resin used is usually 50 to 1000 parts by weight, preferably 100 to 500 parts by weight, per 100 parts by weight of the charge transporting agent. In addition to the above, various additives for improving the mechanical strength and durability of the coating film can be used in the charge transport layer. Examples of such additives include well-known plasticizers, various stabilizers, flowability-imparting agents, and crosslinking agents. The thickness of the charge transport layer is usually 10 to 60 μm, preferably 10 to 45 μm, and more preferably 27 to 40 μm.

Next, as an exposure apparatus for performing exposure for forming a latent image on a photoreceptor, an apparatus for performing digital exposure is used. When oxytitanium phthalocyanine is used as a charge generating agent, the absorbance is measured. Considering
An exposure apparatus that emits a laser beam of 600 to 850 nm is preferable. More specifically, around 635 nm, 650 nm
An exposure apparatus that emits a laser beam at around 780 nm is preferred.

The reason why the image forming method of the present invention exerts the above-mentioned effects is not necessarily clear, but is presumed as follows. That is, since the specific polysiloxane compound used in the present invention can be relatively uniformly distributed in the outermost layer of the photoreceptor, preferably in the charge transport layer, the adhesion of the outermost layer of the photoreceptor to the resin is low. Become. If the toner is manufactured by a wet polymerization method capable of reducing the number of contact points with the photoreceptor, even if the toner has a relatively small particle diameter of 3 to 8 μm, the transferability is good. Therefore, such a combination of the photoconductor and the toner is advantageous for forming a high-definition image.

Further, even when a toner having a high wax content of 5 to 40% is used, filming due to the wax on the photoreceptor can be suppressed. I can be satisfied.

[0105]

EXAMPLES Next, the embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. In the following examples, “parts” means “parts by weight”. The average particle size, the weight average molecular weight, and the 50% circularity were measured by the following methods.

Volume average particle number, number average particle diameter: Nikkiso Co., Ltd. Microtrac UPA (ultra particle analyze)
r), was measured using a Coulter Counter Multisizer Type II (hereinafter, abbreviated as Coulter Counter) manufactured by Coulter Corporation.

Weight average molecular weight (Mw): Measured by gel permeation chromatography (GPC) (apparatus: GPC apparatus HLC-8020 manufactured by Tosoh Corporation, column: PL-gel Mixed-B 10μ manufactured by Polymer Laboratory,
(Solvent: THF, sample concentration: 0.1 wt%, calibration curve: standard polystyrene)

Number of particles having a particle size of 0.6 to 2.12 μm: Measured by a flow particle image analyzer FPIA-2000 manufactured by Sysmex Corporation.

50% circularity: The toner was measured by a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation, and the circularity corresponding to the cumulative particle size distribution value at 50% of the value obtained from the following equation was used. .

[0110]

## EQU1 ## Circularity = perimeter of a circle having the same area as the particle projection area
Perimeter of particle projection image

[Production of toner for development-1 (T1)] (Preparation of wax dispersion-1) 68.33 parts of demineralized water, 30 parts of stearic acid ester of pentaerythritol (Unistar H-476, manufactured by NOF CORPORATION), 1.67 parts of sodium dodecylbenzenesulfonate (Neogen SC, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., active ingredient 66%) were mixed, and emulsified by applying high-pressure shear at 90 ° C. to obtain a dispersion of ester wax fine particles.

(Preparation of Polymer Primary Particle Dispersion-1) 30 parts of wax dispersion-1 were placed in a reactor equipped with a stirrer, a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device.
1.2 parts of a 5% neogen SC aqueous solution and 393 parts of demineralized water are charged, and the temperature is raised to 90 ° C. under a nitrogen stream, and 1.6 parts of an 8% aqueous hydrogen peroxide solution and 1.6 parts of an 8% ascorbic acid aqueous solution are added. did. Thereafter, a mixture of the following monomers and an aqueous solution of an emulsifier was added over 5 hours from the start of the polymerization, and an aqueous solution of the initiator was added over 6 hours from the start of the polymerization, and the mixture was further maintained for 30 minutes.

[0113]

[Table 1] [Monomers] Styrene 79 parts Butyl acrylate 21 parts Acrylic acid 3 parts Bromotrichloromethane 0.45 parts 2-mercaptoethanol 0.01 parts Hexanediol diacrylate 0.9 parts [Emulsifier aqueous solution] 15% Neogen SC aqueous solution 1 part Demineralized water 25 parts [Initiator aqueous solution] 8% Hydrogen peroxide aqueous solution 9 parts 8% Ascorbic acid aqueous solution 9 parts

After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer dispersion. The weight-average molecular weight of the THF-soluble component of the polymer is 193,000, and the average particle size measured by UPA is 16
It was 3 nm.

(Preparation of Resin Fine Particle Dispersion-1) A reactor equipped with a stirrer, a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device was charged with 5 parts of a 15% neogen SC aqueous solution and 376 parts of deionized water. , The temperature was raised to 90 ° C under a nitrogen stream,
1.6 parts of an 8% aqueous hydrogen peroxide solution and 1.6 parts of an 8% aqueous ascorbic acid solution were added. Thereafter, a mixture of the following monomers / emulsifier aqueous solution was added over 5 hours from the start of polymerization, and the aqueous initiator solution was added over 6 hours from the start of polymerization,
Hold for another 30 minutes.

[0116]

[Table 2] [Monomers] Styrene 88 parts Butyl acrylate 12 parts Acrylic acid 3 parts Bromotrichloromethane 0.5 parts 2-mercaptoethanol 0.01 parts Hexanediol diacrylate 0.4 parts [Emulsifier aqueous solution] 15% Neogen SC aqueous solution 2.5 parts Demineralized water 23 parts [Initiator aqueous solution] 8% hydrogen peroxide aqueous solution 9 parts 8% ascorbic acid aqueous solution 9 parts

After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer dispersion. The weight-average molecular weight of the polymer soluble in THF is 87,000, and the average particle size measured by UPA is 123 n.
m.

(Preparation of Colorant Fine Particle Dispersion-1) Pigment Blue 15: 3 aqueous dispersion (EP-700)
Blue GA, manufactured by Dainichi Seika, solid content 35%) UPA
The average particle size measured by was 150 nm.

(Production of Developing Toner-1)

Table 3 Polymer Primary Particle Dispersion-1 95 parts (as solid content) Resin Fine Particle Dispersion-1 5 parts (as solid content) Colorant Fine Particle Dispersion-1 6.7 parts (as solid content) 15% Neogen SC 1.5 parts of aqueous solution (as solid content)

Using the above-mentioned components, a toner was manufactured according to the following procedure. Polymer primary particle dispersion and 1
A 5% neogen SC aqueous solution was charged and uniformly mixed, and then, the coloring agent fine particle dispersion liquid 1 was added and uniformly mixed. While stirring the resulting mixed dispersion, an aqueous solution of aluminum sulfate was added dropwise (0.6 part as a solid content). Thereafter, with stirring, the temperature was raised to 60 ° C. over 1 hour and 25 minutes and maintained for 1 hour, and further raised to 66 ° C. over 1 hour and 30 minutes and maintained for 30 minutes. The dispersion of the resin fine particles and the aqueous solution of aluminum sulfate (0.07 parts as solid content) were added in this order, and the mixture was maintained for 1 hour, and heated to 68 ° C. over 30 minutes. 15% Neogen S
After the addition of the aqueous solution C (3.5 parts as a solid content), the temperature was raised to 93 ° C. over 1 hour and 42 minutes and maintained for 3 hours. Thereafter, the mixture was cooled, filtered, washed with water, and dried to obtain a toner.

To 100 parts of this toner, 2 parts of silica subjected to hydrophobic surface treatment were mixed and stirred, and a developing toner (T
1) was obtained. (Evaluation of Toner-1) The volume average particle diameter of the developing toner (T1) measured by a Coulter counter was 7.4 μm, and Dv /
Dn = 1.19 and the 50% circularity was 0.95.

[Production of Developing Toner-2 (T2)]

Table 4 Polymer Primary Particle Dispersion-1 95 parts (as solid content) Resin Fine Particle Dispersion-1 5 parts (as solid content) Colorant Fine Particle Dispersion-1 6.7 parts (as solid content) 15% Neogen SC 1.5 parts of aqueous solution (as solid content)

A toner was manufactured using the above-mentioned components according to the following procedure. Polymer primary particle dispersion and 1
A 5% neogen SC aqueous solution was charged and uniformly mixed, and then, the coloring agent fine particle dispersion liquid 1 was added and uniformly mixed. While stirring the resulting mixed dispersion, an aqueous solution of aluminum sulfate was added dropwise (0.6 part as a solid content). Thereafter, with stirring, the temperature was raised to 60 ° C. over 35 minutes and maintained for 1 hour, and further raised to 67 ° C. over 1 hour and 14 minutes and maintained for 15 minutes. Next, a resin fine particle dispersion liquid 1 and an aqueous solution of aluminum sulfate (0.07 part as a solid content) were added in this order, and added.
The temperature was raised to 69 ° C. over 30 minutes. After adding a 15% aqueous solution of Neogen SC (3.5 parts as a solid content), the temperature was raised to 98 ° C. over 24 minutes and maintained for 2 hours. Thereafter, the mixture was cooled, filtered, washed with water, and dried to obtain a toner. To 100 parts of this toner, 2 parts of silica subjected to hydrophobic surface treatment were mixed and stirred to obtain a developing toner (T2).

(Evaluation of Toner-2) Toner for development (T
The volume average particle diameter by the Coulter counter of 2) is 7.
8 μm, Dv / Dn = 1.18, and the 50% circularity was 0.95.

[Production of photoreceptor-1] (Preparation of charge generation layer) 10 parts of β-type oxytitanium phthalocyanine and 5 parts of polyvinyl butyral (trade name # 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) -500 parts of dimethoxyethane was added, and pulverized and dispersed by a sand grind mill. This dispersion was dip-coated on an aluminum cylinder having an alumite-finished surface and an outer diameter of 30 mm, a length of 254 mm and a wall thickness of 1.0 mm, and the weight after drying was 0.4 g / m ² (about 0.4 μm ) To form a charge generation layer. (Preparation of charge transport layer) Next, on this charge generation layer, 60 parts of the following charge transport agent (A), 8 parts of a phenolic compound (B) as an antioxidant, and 0.1 part of a cyano compound (C)
5 parts, alkyl / alkoxy-modified polysiloxane (D)
A solution prepared by dissolving 0.3 part and 100 parts of the polyarylate resin (E) in a mixed solvent of tetrahydrofuran and toluene is applied by dip coating, and air-dried at room temperature to obtain a dry film thickness of about 17.5 μm.
The charge transport layer was provided such that The electrophotographic photosensitive member thus obtained is designated as A1.

[0126]

Embedded image

[0127]

Embedded image

[0128]

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[Production of Photoreceptor-2: Comparative Photoreceptor] In Production of Photoreceptor-1, dimethylpolysilicone (trade name KF96, manufactured by Shin-Etsu Silicone Co., Ltd.) was used instead of the alkyl / alkoxy-modified polysiloxane (compound D). ) 0.
A photoconductor was prepared in the same manner as in Production-1 of photoconductor except that 3 parts were used. This electrophotographic photosensitive member is designated as B1.

[Preparation of photoreceptor-3: Comparative photoreceptor] The same procedure as in Preparation of photoreceptor-1 was carried out except that alkyl / alkoxy-modified polysiloxane (compound D) was not blended in Preparation of photoreceptor-1. To produce a photoreceptor. This electrophotographic photosensitive member is designated as B2.

Example 1 A laser printer (LP-1900; manufactured by Epson Corporation) was used for electrophotographic photosensitive member A1 and toner T2.
, And an image was displayed. The measurement image was formed by printing a band image at image densities of 13 (black solid), 6 (halftone 1), and 3 (halftone 2), which were obtained by dividing white solid to black solid into 13 stages. In the measurement of the image density, the printer is stopped before the fixing process of the image, and the density (X1) of the toner on the paper before the image fixing and the electrophotographic photosensitive member corresponding to the image transferred to the paper remain. The toner density (X2) was measured using a Macbeth densitometer. The densities (X1, X2) thus obtained were calculated according to the following formulas, and used as transfer rates. When measuring the concentration, the background concentration was measured in advance, and the respective values (X
The value obtained by subtracting the background value from (1, X2) was defined as (X1 ′, X2 ′).

[0132]

## EQU2 ## Transfer rate (%) = [X1 ′ / (X1 ′ + X)
2 ′)] × 100 The results are shown in Table 1.

[Comparative Example 1] In Example 1, the photosensitive member was changed to A
Image transfer was performed in the same manner except that B1 was used instead of 1, and the transfer rate was measured. The results are shown in Table 1. [Comparative Example 2] In Example 1, the photosensitive member was replaced with B instead of A1.
Image transfer was performed in the same manner except that the transfer rate was set to 2, and the transfer rate was measured. The results are shown in Table 1.

[0134]

[Table 5]

Example 2 Using the photoreceptor A1 and the toner T1, an image was printed in black solid (density 13) in the same manner as in Example 1, and the transfer rate was calculated. The transfer rate was 93%. [Comparative Example 3] Photoreceptor A1 and LP-1900 genuine kneading /
Using a toner obtained by the pulverization method, an image was printed in black solid (density 13) in the same manner as in Example 1, and the transfer rate was calculated.
The transfer rate was 90%. [Comparative Example 4] Photosensitive member B2 and LP-1900 genuine kneading /
Using a toner obtained by the pulverization method, an image was printed in black solid (density 13) in the same manner as in Example 1, and the transfer rate was calculated.
The transfer rate was 88%.

From Example 1 and Comparative Examples 1 and 2, the transfer rate of the toner produced by the wet polymerization method is higher and better when the photosensitive member in which the specific polysiloxane is blended in the outermost layer is used. . Further, from Examples 1 and 2 and Comparative Examples 3 and 4, when the photoconductors are the same, the toner manufactured by the wet polymerization method has a higher transfer rate and is better than the toner manufactured by the kneading / pulverizing method. Further, by comparing Example 1 with Comparative Example 2 and Comparative Example 3 and Comparative Example 4, the outermost layer containing a specific polysiloxane compound was more effective when the toner produced by the wet polymerization method was used. It can be seen that there is a large difference between the transfer rate when using the photoreceptor having the formula (1) and the transfer rate when using the photoreceptor having the outermost layer containing no polysiloxane compound. That is, it is shown that a special effect is exhibited by combining a photoreceptor having an outermost layer containing a polysiloxane compound and a toner produced by a wet polymerization method.

[0137]

As described above, by using a photoreceptor using the above-mentioned polysiloxane compound having a specific structural unit for the outermost layer and a toner produced by a wet polymerization method, the transferability is good, and It is possible to provide an image forming method and an image forming apparatus in which the filming of the toner on the toner is small. Also,
According to the apparatus and method of the present invention, a high-gradation, high-resolution image can be obtained, and the present invention can be advantageously applied to a small, high-speed image forming apparatus.

[0138]

[Brief description of the drawings]

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 charging device 3 exposure device 4 developing tank 5 transfer device 6 cleaning device 7 fixing device 42 agitator 43 supply roller 44 developing roller 45 regulating member 71 upper fixing member 72 lower fixing member T toner P recording paper

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 9/08 G03G 9/08 365 365 9/087 384 15/04 15/04 120 15/043 21/00 312 21/10 (72) Inventor Shunichiro Kurihara 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 2H005 AA06 AA15 AB06 CA14 EA03 EA05 EA10 2H068 AA03 AA13 AA19 AA20 BA12 BA39 BB27 BB33 2H076 AB02 AB09 AB42 DA37 2H134 GA01 GB02 GB08 HB00 HD00 KG07 KG08 KH01

Claims (21)

[Claims] 1. An image forming apparatus comprising at least a photoreceptor and a toner, wherein the outermost layer of the photoreceptor has a structural unit represented by the following general formula (1a) and a structural unit represented by the following general formula (1b) Having a volume average particle size (Dv) of 3 to 8 μm.
m, wherein the image forming apparatus is manufactured by a wet polymerization method. Embedded image (In the general formulas (1a) and (1b), R ¹ and R ³ each independently represent a hydrocarbon group which may have a substituent;
² represents a hydrocarbon group having 3 or more carbon atoms, which may have a substituent, R ⁴ represents a divalent hydrocarbon group having 1 to 3 carbon atoms, and R ⁵ represents 3 or more carbon atoms. Represents a hydrocarbon group which may have a substituent. ) 2. The image forming apparatus according to claim 1, wherein in the general formula (1b), R ⁵ is an alkyl group having an isopropyl unit or a tertiary butyl unit. 3. The image forming apparatus according to claim 1, wherein the toner has a 50% circularity of 0.9 to 1. However, 50
The% circularity is expressed by the formula: circularity = perimeter of a circle having the same area as the projected area of the particle / perimeter of the projected image of the particle, which is 50, which is a value obtained from the formula.
% Corresponds to the cumulative particle size distribution value in%. 4. The toner according to claim 1, wherein the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the toner is 1 to 1.3. Image forming apparatus. 5. A toner according to claim 1, wherein a flow particle analyzer measures the number (number) of particles having a particle size of 0.6 to 2.12 μm,
The image forming apparatus according to claim 1, wherein the number of particles is 5% or less of the total number of particles. 6. The image forming apparatus according to claim 1, wherein the toner contains 1 to 30% of wax. 7. The image forming apparatus according to claim 1, wherein the toner is obtained by an emulsion polymerization / aggregation method. 8. The image forming apparatus according to claim 6, wherein the melting point of the wax is 30 to 100 ° C. 9. The ratio of the number of carbon atoms (N _C ) to the number of silicon atoms (N _Si ) in the polysiloxane compound (N _C / N _Si )
The image forming apparatus according to any one of claims 1 to 8, wherein the number is from 4 to 20. 10. The image forming apparatus according to claim 1, wherein the photoconductor is obtained by laminating at least a charge generation layer and a charge transport layer on a conductive support in this order. 11. The image forming apparatus according to claim 10, wherein the outermost layer of the photoconductor is a charge transport layer. 12. The image forming apparatus according to claim 11, wherein the binder resin of the charge transport layer contains polyarylate. 13. The polyarylate represented by the following general formula (9)
The image forming apparatus according to claim 12, further comprising a structural unit represented by: Embedded image (In the general formula (9), Ar ¹¹ and Ar ¹² each independently represent a benzene ring which may have a substituent, and X represents a divalent aliphatic hydrocarbon which may have a substituent. R ²¹ and R ²² each independently represent a group, a benzene ring which may have a substituent, a naphthalene ring which may have a substituent, or a biphenyl ring which may have a substituent. Represents an aryl group which may have a substituent, an acyloxy group which may have a substituent, and an arylsulfoxy group which may have a substituent, wherein R ²¹ and R ²² are To form a ring structure.) 14. The image forming apparatus according to claim 10, wherein the charge transport layer contains a compound represented by the following general formula (2). Embedded image (In the general formula (2), Ar ¹ represents an optionally substituted benzene ring, an optionally substituted naphthalene ring, or an optionally substituted biphenyl ring;
^{2 to} Ar ⁵ each independently represent an aromatic ring which may have a substituent. ) 15. The image forming apparatus according to claim 10, wherein the charge generation layer contains oxytitanium phthalocyanine. 16. An image forming method using at least a photoconductor, an exposure device, and an image forming apparatus provided with a toner, wherein the outermost layer of the photoconductor includes a structural unit represented by the following general formula (1a) and a general formula: A polysiloxane compound having a structural unit represented by (1b) in the molecule is contained, and the photoreceptor is subjected to digital image exposure by the exposure apparatus,
An electrostatic latent image is formed on a photoreceptor, and in the development of the electrostatic latent image, a volume average particle diameter (Dv) produced by a wet polymerization method
An image forming method using a toner having a particle size of 3 to 8 μm. Embedded image (In the general formulas (1a) and (1b), R ¹ and R ³ each independently represent a hydrocarbon group which may have a substituent;
² represents a hydrocarbon group having 3 or more carbon atoms, which may have a substituent, R ⁴ represents a divalent hydrocarbon group having 1 to 3 carbon atoms, and R ⁵ represents 3 or more carbon atoms. Represents a hydrocarbon group which may have a substituent. ) 17. The image forming method according to claim 16, wherein a digital image exposure having a recording dot density of 600 dots / inch or more is performed by an exposure device. 18. The image forming method according to claim 16, wherein the charge generation layer contains oxytitanium phthalocyanine. 19. The image forming method according to claim 16, wherein the exposure device emits a laser beam having a wavelength of 600 to 850 nm. 20. A toner having a 50% circularity of 0.96 to 0.96.
The image forming method according to any one of claims 16 to 19, wherein the value is 0.995, and the method does not include a step of removing residual toner on the photosensitive member by a cleaning device. 21. A toner having a 50% circularity of 0.92 to
2. The cleaning device according to claim 1, further comprising a step of removing residual toner on the photosensitive member by a cleaning device.
20. The image forming method according to any one of 6 to 19.