JP2002357913A - Image forming method, image forming device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method, an image forming device and a process cartridge using a photoreceptor over a long term, which has such durability that the depletion of film thickness is >=15 μm by combination with an intermediate layer to which N type semiconductor particles are added, which does not cause a black spot, the lowering of image density, the occurrence of fogging and cracks, especially, under environmental characteristic such as high temperature and high humidity, and where the adhesion of the intermediate layer to a lower layer is excellent. SOLUTION: In this image forming method, at least electrification, exposure, development with toner and transfer are repeated by rotating an electrophotographic sensitive body having the intermediate layer between a conductive supporting body and a photoreceptive layer, and the intermediate layer incorporates the N type semiconductor particles and binder, then the variation coefficient of the shape factor of the toner is <=16% and the number variation coefficient in number particle size distribution thereof is <=27%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming method, an image forming apparatus, and a process cartridge, and more particularly, to an image forming method, an image forming apparatus, and a process cartridge used for forming an electrophotographic image.

[0002]

2. Description of the Related Art In order to eliminate moire and black spots by a digital method, an intermediate layer to which fine particles are added has been developed. For example, an electrophotographic photoreceptor having a configuration in which an intermediate layer is provided between a conductive support and a photosensitive layer, and the intermediate layer has titanium oxide particles dispersed in a resin is known. Also, a technique of an intermediate layer containing surface-treated titanium oxide is known. For example, JP-A-4-303846 discloses an iron oxide, titanium oxide surface-treated with tungsten oxide, and JP-A-9-9691.
No. 6, titanium oxide surface-treated with an amino group-containing coupling agent, JP-A-9-258469, titanium oxide surface-treated with an organosilicon compound, JP-A-8-328283
And titanium oxide surface-treated with methylhydrogenpolysiloxane.

In order to obtain high resolution, toners having a particle size distribution within a certain range are also being studied. For example, when polymerized toner is used, the photosensitive layer is
At a film thickness in the vicinity, black spots may occur in a severe environment of high temperature and high humidity or low temperature and low humidity, or the residual potential may increase due to repeated use, and the exposure area potential may increase. It cannot be obtained, and the electrophotographic performance is deteriorated due to weak adhesion to the lower layer. It is not well known that the amount of wear of the polymerized toner is large, but particles of uniform size behave like a sharpened blade, and the photosensitive layer is scraped, and the adhesion of the toner to the photoconductor Is considered to be performed under severe cleaning conditions.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the thickness loss by combining with an intermediate layer to which N-type semiconductor particles are added.
It has a durability of 5 μm or more, in particular, has no black spots, reduced image density, fog, cracks, etc. under environmental characteristics of high temperature and high humidity, has good adhesion to the lower layer, and can be used for a long time. An object of the present invention is to provide an image forming method, an image forming apparatus, and a process cartridge.

[0005]

The above object of the present invention has been attained by the following constitutions.

[0006] 1. In an image forming method in which an electrophotographic photosensitive member having an intermediate layer is rotated between a conductive support and a photosensitive layer, and at least charging, exposure, development with toner, and transfer are repeated, the intermediate layer includes N-type semiconductor particles and a binder. The toner has a shape coefficient variation coefficient of 16% or less and a number variation coefficient in the number particle size distribution of 27%.
An image forming method characterized by the following.

[0007] 2. 2. The image forming method according to item 1, wherein the N-type semiconductor particles have a number average primary particle size of 10 nm or more and 200 nm or less.

[0008] 3. 3. The image forming method according to the above item 1 or 2, wherein the N-type semiconductor particles are metal oxide particles.

4. 4. The image forming method according to any one of items 1 to 3, wherein the N-type semiconductor particles are titanium oxide particles.

[0010] 5. The method according to item 4, wherein the titanium oxide particles have been subjected to a surface treatment a plurality of times, and the final surface treatment is a surface treatment with a reactive organosilicon compound.
3. The image forming method according to 1.,

6. 6. The image forming method according to the above item 5, wherein the reactive organic silicon compound is methyl hydrogen polysiloxane.

7. 6. The image forming method according to the item 5, wherein the reactive organic silicon compound is an organic silicon compound represented by the following general formula (1).

General formula (1) R—Si— (X) ₃ (wherein R represents an alkyl group or an aryl group, and X represents a methoxy group, an ethoxy group, or a halogen group). 8. The image forming method according to the item 7, wherein R in the general formula (1) is an alkyl group having 4 to 8 carbon atoms.

9. The method according to any one of the above items 5 to 8, wherein at least one of the plurality of surface treatments is a surface treatment of at least one compound selected from alumina, silica, and zirconia. The image forming method as described in the above.

10. The image formation according to any one of the above items 4 to 9, wherein the titanium oxide particles are subjected to a surface treatment with both or one of silica and alumina, and then subjected to a surface treatment with a reactive organosilicon compound. Method.

11. 5. The image forming method according to the item 4, wherein the titanium oxide particles have been subjected to a surface treatment with an organosilicon compound having a fluorine atom.

[12] The image forming method according to any one of Items 1 to 11, wherein a binder of the intermediate layer is a polyamide resin.

13. The toner has a shape factor of 1.0 to
13. The image forming method according to any one of the above items 1 to 12, wherein the toner particles have a number of 65% by number or more in the range of 1.6.

14. The toner has a shape factor of 1.2 to
13. The image forming method according to any one of the above items 1 to 12, wherein the toner particles have a number of 65% by number or more in the range of 1.6.

15. Wherein the toner contains 50% by number or more of toner particles having no corners.
3. The image forming method according to any one of 2.

16. The number average particle diameter of the toner is 3 to 8
any one of the above items 1 to 15,
Item.

17. The particle size of the toner particles is D (μm)
, The natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23, and the relative frequency (m1) of the toner particles included in the most frequent class in the histogram showing the number-based particle size distribution Wherein the sum (M) of the relative frequency (m2) of the toner particles included in the class having the highest frequency after the mode is 70% or more.
17. The image forming method according to any one of items 16 to 16.

18. 18. The image forming method according to any one of items 1 to 17, wherein the toner is obtained from colored particles obtained by polymerizing at least a polymerizable monomer in an aqueous medium.

19. 19. The image forming method according to any one of items 1 to 18, wherein the toner is obtained from colored particles obtained by associating at least resin particles in an aqueous medium.

20. Wherein the toner contains a styrene- (meth) acrylate-based resin.
20. The image forming method according to any one of items 19 to 19.

21. 21. An image forming apparatus having at least a charging unit, an exposing unit, a developing unit, and a transferring unit around an electrophotographic photosensitive member and performing image formation repeatedly, wherein an image forming method according to any one of 1 to 20 above. An image forming apparatus, which is an image forming method.

22. A process cartridge used in an image forming apparatus that has at least a charging unit, an exposing unit, a developing unit, and a transferring unit around the electrophotographic photosensitive member, and that repeatedly performs image formation. The image forming apparatus includes at least one of a developing unit, a transfer unit, and a cleaning unit, and is configured to be able to be taken in and out of the image forming apparatus.
13. A process cartridge for use in the image forming method according to item 13.

The present invention will be described in more detail. The electrophotographic photoreceptor of the present invention (hereinafter, also simply referred to as a photoreceptor) is characterized in that particles are contained in an intermediate layer provided between a conductive support and a photosensitive layer.

The average particle size of the N-type semiconductor particles used in the present invention is preferably in the range of 10 nm to 200 nm in number average primary particle size, and more preferably 15 nm to 150 nm. If it is less than 10 nm, black spots cannot be prevented,
If it is larger than 200 nm, the dispersion stability is poor, and black spots increase. An intermediate layer coating solution using particles having a number average primary particle diameter in the above range has good dispersion stability, and an intermediate layer formed from such a coating solution has a sufficient black spot prevention function and environmental characteristics. Has cracking resistance.

The number average primary particle size of the N-type semiconductor particles is, for example, 1 in the case of titanium oxide by observation with a transmission electron microscope.
It is a measurement value as an average diameter in the Feret direction obtained by observing 100 particles as primary particles at a magnification of 10,000 times and randomly observing the particles.

The particles of the intermediate layer are N-type semiconductor particles, particularly preferably a metal oxide. Specifically, titanium oxide (T
Fine particles such as iO ₂ ), zinc oxide (ZnO), and tin oxide (SnO ₂ ) can be mentioned. Among them, titanium oxide is preferable, and furthermore, surface treatment is preferably performed to achieve good dispersibility. The content of the particles in the intermediate layer is preferably 10% to 90% by volume, and more preferably 25%.
To 75% is preferred.

The titanium oxide particles have dendritic, acicular and granular shapes, and the titanium oxide having such a shape includes anatase type, rutile type and amorphous type. However, any shape and crystal form may be used, and two or more kinds of shapes and crystal forms may be mixed and used.

Here, the N-type semiconductor particles are fine particles having the property of using the conductive carriers as electrons. That is,
The property that the conductive carrier is used as an electron means that by including the N-type semiconductor particles in an insulating binder, hole injection from the substrate is efficiently blocked, and electrons from the photosensitive layer are blocked. It has a property that does not show the property.

The surface treatment of the N-type semiconductor particles means that the surface of the N-type semiconductor particles is coated with a metal oxide, a reactive organosilicon compound, an organometallic compound or the like. Particularly preferred surface treatment of the N-type semiconductor particles used in the present invention will be described below.

One of the preferable surface treatments of the N-type semiconductor particles is that a plurality of surface treatments are performed, and the last one of the plurality of surface treatments is a surface treatment with a reactive organosilicon compound. It is characterized by having.

Another preferred surface treatment of the N-type semiconductor particles is characterized in that the surface treatment is performed with methyl hydrogen polysiloxane.

Another preferred surface treatment of the N-type semiconductor particles is characterized in that the surface treatment is carried out with an organosilicon compound having a fluorine atom.

By providing the intermediate layer between the conductive support and the photosensitive layer by containing the N-type semiconductor particles subjected to any one of the above three surface treatments, the residual potential, the charged potential, etc. The occurrence of black spots can be significantly suppressed without deteriorating the electrophotographic characteristics, and the occurrence of moire due to laser exposure can be improved.

One of the surface treatments performed on the N-type semiconductor particles of the present invention is to perform a plurality of surface treatments, and the last one of the plurality of surface treatments is a reactive organic compound. The surface treatment with a silicon compound is performed. At least one of the plurality of surface treatments uses at least one compound selected from alumina (Al ₂ O ₃ ), silica (SiO ₂ ), and zirconia (ZrO ₂ ). It is preferable that the surface treatment is performed by a reactive organosilicon compound. These compounds include those having a hydrate.

As another method of the surface treatment performed on the N-type semiconductor particles of the present invention, the surface treatment is performed a plurality of times, and the reactive is applied to the last surface treatment among the plurality of the surface treatments. The surface treatment is performed using an organic titanium compound or a reactive organic zirconium compound. Further, among the plurality of surface treatments, at least one surface treatment is performed using at least one compound selected from alumina, silica, and zirconia as described above, and finally, a reactive organic titanium compound or It is preferable to perform a surface treatment with a reactive organic zirconium compound.

As described above, by performing the surface treatment of the N-type semiconductor particles such as the titanium oxide particles at least twice, the surface of the N-type semiconductor particles is uniformly coated (treated), and the surface-treated N-type semiconductor particles are treated. When the type semiconductor particles are used for the intermediate layer, it is possible to obtain a good photoreceptor having good dispersibility of N type semiconductor particles such as titanium oxide particles in the intermediate layer and not generating image defects such as black spots. is there.

Further, the surface treatment is performed a plurality of times by using alumina and silica, followed by a surface treatment with a reactive organic silicon compound, or a reactive organic silicon compound is used after the surface treatment with alumina and silica. Those that perform a surface treatment using a titanium compound or a reactive organic zirconium compound are particularly preferable.

The above-mentioned treatment of alumina and silica may be carried out simultaneously. In particular, the treatment of alumina is carried out first,
Next, it is preferable to perform a silica treatment. In the case where alumina and silica are respectively treated, the amount of alumina and silica to be treated is preferably larger than that of alumina.

The surface treatment of the N-type semiconductor particles such as titanium oxide with a metal oxide such as alumina, silica, and zirconia can be performed by a wet method. For example, silica,
Alternatively, N-type semiconductor particles having been subjected to alumina surface treatment can be produced as follows.

When titanium oxide particles are used as the N-type semiconductor particles, titanium oxide particles (number average primary particle diameter: 50 n
m) is dispersed in water at a concentration of 50 to 350 g / L to obtain an aqueous slurry, to which a water-soluble silicate or a water-soluble aluminum compound is added. Then, an alkali or acid is added to neutralize the silica, and the surface of the titanium oxide particles is silica,
Alternatively, alumina is deposited. Subsequently, filtration, washing and drying are performed to obtain a target surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid or hydrochloric acid. on the other hand,
When aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.

The amount of the metal oxide used in the surface treatment is 0.1 to 5 parts by mass with respect to 100 parts by mass of the N-type semiconductor particles such as titanium oxide particles in the charged amount at the time of the surface treatment.
0 parts by mass, more preferably 1 to 10 parts by mass of a metal oxide is used. When the above alumina and silica are used, for example, in the case of titanium oxide particles, titanium oxide particles 10
It is preferable to use 1 to 10 parts by mass with respect to 0 parts by mass, and it is preferable that the amount of silica is larger than that of alumina.

The surface treatment with the reactive organic silicon compound, which is performed after the surface treatment with the metal oxide, is preferably performed by the following wet method.

That is, the titanium oxide treated with the metal oxide is added to a solution in which the reactive organosilicon compound is dissolved or suspended in an organic solvent or water, and the solution is stirred for several minutes to one hour. I do. In some cases, the liquid is subjected to a heat treatment, filtered, etc., and then dried to obtain titanium oxide particles whose surface is coated with an organosilicon compound. Note that the reactive organic silicon compound may be added to a suspension in which titanium oxide is dispersed in an organic solvent or water.

In the present invention, the fact that the surface of the titanium oxide particles is coated with the reactive organosilicon compound is as follows.
Photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Au
ger) is confirmed by combining surface analysis methods such as secondary ion mass spectrometry (SIMS) and diffuse reflection FI-IR.

The amount of the reactive organosilicon compound used in the surface treatment is such that the amount of the reactive organosilicon compound is 0 with respect to 100 parts by mass of the titanium oxide treated with the metal oxide at the amount charged during the surface treatment. 0.1 to 50 parts by mass, more preferably 1 to 10 parts by mass. If the surface treatment amount is less than the above range, the surface treatment effect is not sufficiently provided, and the dispersibility and the like of the titanium oxide particles in the intermediate layer deteriorate.
Further, when the value exceeds the above range, the electric performance is deteriorated, resulting in an increase in the residual potential and a decrease in the charged potential.

Examples of the reactive organosilicon compound used in the present invention include compounds represented by the following general formula (2), provided that the compound is capable of undergoing a condensation reaction with a reactive group such as a hydroxyl group on the surface of titanium oxide. Are not limited to the following compounds.

Formula (2) (R ₁ ) _n -Si- (X ₁ ) _4-n (wherein, Si represents a silicon atom, and R ₁ represents an organic group in which carbon is directly bonded to the silicon atom. , X ₁ represents a hydrolyzable group, and n represents an integer of 0 to 3.) In the organosilicon compound represented by the general formula (2), R
Examples of the organic group in which carbon is directly bonded to silicon represented by ₁ include an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and dodecyl, an aryl group such as phenyl, tolyl, naphthyl, and biphenyl; epoxy-containing groups such as γ-glycidoxypropyl and β- (3,4-epoxycyclohexyl) ethyl, (meth) acryloyl-containing γ-acryloxypropyl and γ-methacryloxypropyl, γ-hydroxypropyl,
Hydroxyl groups such as 2,3-dihydroxypropyloxypropyl, vinyl groups such as vinyl and propenyl, mercapto groups such as γ-mercaptopropyl, γ-aminopropyl, N-β (aminoethyl) -γ-aminopropyl And a halogen-containing group such as γ-chloropropyl, 1,1,1-trifluoropropyl, nonafluorohexyl and perfluorooctylethyl, and other nitro and cyano-substituted alkyl groups. Examples of the hydrolyzable group for X ₁ include an alkoxy group such as methoxy and ethoxy, a halogen group, and an acyloxy group.

Further, the organosilicon compounds represented by the general formula (2) may be used alone or in combination of two or more.

When n is 2 or more in the specific compound of the organosilicon compound represented by the general formula (2), a plurality of R
₁ may be the same or different. Similarly, when n is 2 or less, a plurality of X ₁ may be the same or different.
When two or more organosilicon compounds represented by the general formula (2) are used, R ₁ and X ₁ may be the same or different between the respective compounds.

Examples of the compound where n is 0 include the following compounds. Tetrachlorosilane, diethoxydichlorosilane, tetramethoxysilane, phenoxytrichlorosilane, tetraacetoxysilane, tetraethoxysilane, tetraallyloxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrakis (2-methoxyethoxy) silane, tetrabutoxysilane , Tetraphenoxysilane, tetrakis (2-ethylbutoxy) silane, tetrakis (2-ethylhexyloxy) silane and the like.

Examples of the compound where n is 1 include the following compounds. That is, trichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, ethyltrichlorosilane, allyltrichlorosilane, n-propyltrichlorosilane, n-butyltrichlorosilane, chloromethyltriethoxysilane, methyltrimethoxysilane, mercaptomethyltrimethoxysilane, Trimethoxyvinylsilane, ethyltrimethoxysilane, 3,3,4
4,5,5,6,6,6-nonafluorohexyltrichlorosilane, phenyltrichlorosilane, 3,3,3-
Trifluoropropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, triethoxysilane, 3
-Mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, benzyltrichlorosilane, methyltriacetoxysilane, chloromethyltriethoxysilane, ethyltriacetoxysilane, phenyltrimethoxysilane, 3-allylthiopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-allylaminopropyltrimethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, 3-aminopropyl Triethoxysilane, 3-methacryloxypropyltrimethoxysilane, bis (ethylmethylketoxime) methoxymethylsilane, pentyltriethoxysilane, octyl Triethoxysilane, a dodecyloxy triethoxy silane and the like.

Examples of the compound wherein n is 2 include the following compounds. Dimethyldichlorosilane, dimethoxymethylsilane, dimethoxydimethylsilane, methyl-3,
3,3-trifluoropropyldichlorosilane, diethoxysilane, diethoxymethylsilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3-chloropropyldimethoxymethylsilane, chloromethyldiethoxysilane, diethoxydimethyl Silane, dimethoxy-3-mercaptopropylmethylsilane, 3,3
4,4,5,5,6,6,6-nonafluorohexylmethyldichlorosilane, methylphenyldichlorosilane,
Diacetoxymethylvinylsilane, diethoxymethylvinylsilane, 3-methacryloxypropylmethyldichlorosilane, 3-aminopropyldiethoxymethylsilane, 3- (2-aminoethylaminopropyl) dimethoxymethylsilane, t-butylphenyldichlorosilane,
3-methacryloxypropyldimethoxymethylsilane,
3- (3-cyanopropylthiopropyl) dimethoxymethylsilane, 3- (2-acetoxyethylthiopropyl) dimethoxymethylsilane, dimethoxymethyl-2-
Piperidinoethylsilane, dibutoxydimethylsilane,
3-dimethylaminopropyldiethoxymethylsilane,
Diethoxymethylphenylsilane, diethoxy-3-glycidoxypropylmethylsilane, 3- (3-acetoxypropylthio) propyldimethoxymethylsilane, dimethoxymethyl-3-piperidinopropylsilane, diethoxymethyloctadecylsilane and the like. Can be

Examples of the compound in which n is 3 include the following compounds. Trimethylchlorosilane, methoxytrimethylsilane, ethoxytrimethylsilane, methoxydimethyl-3,3,3-trifluoropropylsilane, 3-
Chloropropylmethoxydimethylsilane, methoxy-3
-Mercaptopropylmethylsilane and the like.

As the organosilicon compound represented by the general formula (2), an organosilicon compound represented by the following general formula (1) is preferably used.

Formula (1) R-Si- (X) _{3 wherein} R is an alkyl group, an aryl group, X is a methoxy group,
Represents an ethoxy group or a halogen group.

In the organosilicon compound represented by the general formula (1), more preferably, an organosilicon compound in which R is an alkyl group having 4 to 8 carbon atoms is preferable. Examples include n-butylsilane, trimethoxy i-butylsilane, trimethoxyhexylsilane, and trimethoxyoctylsilane.

A preferred reactive organosilicon compound used for the final surface treatment is a hydrogenpolysiloxane compound. The hydrogen polysiloxane compound having a molecular weight of 1,000 to 20,000 is generally easily available, and has a good black spot prevention function. Particularly, when methyl hydrogen polysiloxane is used for the final surface treatment, a good effect can be obtained.

Another one of the surface treatments of the titanium oxide of the present invention is titanium oxide particles which have been surface-treated with an organosilicon compound having a fluorine atom. The surface treatment with the organosilicon compound having a fluorine atom is preferably performed by the above-mentioned wet method.

That is, the above-mentioned organosilicon compound having a fluorine atom is dissolved or suspended in an organic solvent or water, untreated titanium oxide is added thereto, and such a solution is stirred for several minutes to one hour. After the mixture is subjected to a heat treatment in some cases, it is dried through a step such as filtration, and the surface of the titanium oxide is coated with an organosilicon compound having a fluorine atom. The organic silicon compound having a fluorine atom may be added to a suspension in which titanium oxide is dispersed in an organic solvent or water.

The fact that the titanium oxide surface is coated with an organosilicon compound having a fluorine atom is as follows.
Photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Au
ger) can be confirmed compositely using a surface analyzer such as secondary ion mass spectrometry (SIMS) or diffuse reflection FI-IR.

The organosilicon compound having a fluorine atom used in the present invention includes 3,3,4,4,5,5,5
6,6,6-nonafluorohexyltrichlorosilane,
3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldichlorosilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3,3,4,4,5 , 5,6,6
6-nonafluorohexylmethyldichlorosilane and the like.

In the present invention, the surface treatment finally performed on the N-type semiconductor particles may be performed by using a reactive organic titanium compound or a reactive organic zirconium compound. The method is performed by a method according to the surface treatment method using the reactive organosilicon compound.

In addition, the fact that the surface of the N-type semiconductor particles is coated with a reactive organic titanium compound or a reactive organic zirconium compound is determined by photoelectron spectroscopy (ESCA).
It is confirmed with high accuracy by using a combination of surface analysis techniques such as Auger electron spectroscopy (Auger), secondary ion mass spectrometry (SIMS), and diffuse reflection FI-IR.

Specific reactive organotitanium compounds used for the surface treatment of the N-type semiconductor particles include metal alkoxide compounds such as tetrapropoxytitanium and tetrabutoxytitanium, diisopropoxytitanium bis (acetylacetate), diisopropoxide, and the like. Metal chelate compounds such as propoxytitanium bis (ethylacetoacetate), diisopropoxytitanium bis (lactate), dibutoxytitanium bis (octylene glycolate), and diisopropoxytitanium bis (triethanolaminate). Examples of the reactive organic zirconium compound include metal alkoxide compounds such as tetrabutoxyzirconium and butoxyzirconium tri (acetylacetate) and metal chelate compounds.

Next, N-type semiconductor particles such as the above-mentioned surface-treated titanium oxide particles (hereinafter also referred to as surface-treated N-type semiconductor particles. In particular, the surface-treated titanium oxide particles are subjected to the surface treatment. The structure of the intermediate layer using titanium oxide) will be described.

The intermediate layer according to the present invention is formed by dispersing a surface-treated N-type semiconductor particle such as a surface-treated titanium oxide obtained by performing the surface treatment a plurality of times in a solvent together with a binder resin in a conductive support. It is produced by coating on top.

The intermediate layer of the present invention is provided between the conductive support and the photosensitive layer, and has good adhesion between the conductive support and the photosensitive layer and good electron injection from the photosensitive layer to the conductive support. , Mobility, and a barrier function for preventing hole injection from the support. Examples of the binder resin for the intermediate layer include thermosetting resins such as polyamide resin, vinyl chloride resin, vinyl acetate resin, polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin and melamine resin, epoxy resin, and alkyd resin, and these resins. And copolymer resins containing two or more of the above repeating units. Among these binder resins, polyamide resins are particularly preferable, and alcohol-soluble polyamides such as copolymerization and methoxymethylol are particularly preferable. The amount of the surface-treated N-type semiconductor particles of the present invention dispersed in the binder resin is, for example, in the case of surface-treated titanium oxide, 10 to 10,000 parts by mass, preferably 50 to 50 parts by mass, per 100 parts by mass of the binder resin. １，1,000 parts by mass. By using the surface-treated titanium oxide in this range, the dispersibility of the titanium oxide can be kept good, and a good intermediate layer free of black spots can be formed.

The thickness of the intermediate layer of the present invention is 0.5 to 15 μm.
Is preferred. By using the film thickness in the above-mentioned range, an intermediate layer having good electrophotographic characteristics without black spots can be formed.

The coating solution for the intermediate layer prepared to form the intermediate layer of the present invention may be a surface-treated N
It is composed of semiconductor particles, a binder resin, a dispersion solvent, and the like. As the dispersion solvent, those similar to the solvents used for producing other photosensitive layers are appropriately used.

That is, the solvent or dispersion medium used for forming the intermediate layer, photosensitive layer and other resin layers of the present invention is n-
Butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylketone, methylisopropylketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, , 2-Dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolan, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, Methyl cellosolve and the like.

The solvent for the coating solution for the intermediate layer is not limited to these, but methanol, ethanol, butanol, 1-propanol, isopropanol and the like are preferably used. In addition, these solvents can be used alone or as a mixed solvent of two or more kinds.

As the solvent for coating the intermediate layer, it is preferable to use a mixed solvent of methanol and straight-chain alcohol having high resin solubility in order to prevent drying unevenness during coating of the intermediate layer. The ratio of the volume ratio of the linear alcohol to the methanol is 0.05 to 0.
A mixture of 6 is preferred. By using the coating solvent as a mixed solvent in this manner, the evaporation rate of the solvent is appropriately maintained, and the occurrence of image defects due to uneven drying during coating can be suppressed.

As a dispersing means of the surface-treated titanium oxide used for preparing the coating solution for the intermediate layer, any dispersing means such as a sand mill, a ball mill, and an ultrasonic dispersion may be used.

Coating processing methods for manufacturing the electrophotographic photoreceptor of the present invention including the intermediate layer include dip coating,
Coating methods such as spray coating and circular amount control type coating are used, but the coating process on the upper layer side of the photosensitive layer is performed by spray coating or circular coating to minimize the dissolution of the lower layer film and to achieve uniform coating processing. It is preferable to use a coating method such as a regulated type (a typical example is a circular slide hopper type). The spray coating is described in, for example,
No. 90250 and JP-A-3-269238, and the circular amount-control type coating is described in detail, for example, in JP-A-58-189061.

Hereinafter, the constitution of the photosensitive member preferably used in the present invention will be described. The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layered photosensitive layer configuration in which a charge generation function and a charge transport function are provided in one layer on the following conductive support.
It is more preferable to adopt a configuration in which the function of the photosensitive layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL).

<< Conductive Support >> The conductive support of the electrophotographic photoreceptor of the present invention includes: 1) a metal plate or a cylindrical tube of aluminum, stainless steel or the like; 2) aluminum on a support such as paper or plastic film; 3) A thin layer of metal such as palladium and gold laminated or deposited 3) A layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is coated or deposited on a support such as paper or plastic film. And the like provided. Preferably, a cylindrical tube made of aluminum is used. 4) Anodized aluminum or anodized alumite substrate.

<< Charge Generating Layer >> The charge generating layer of the present invention contains a charge generating substance and a binder resin, and is formed by dispersing and applying the charge generating substance in a binder resin solution.

The charge generating substance is a known phthalocyanine compound, preferably a titanyl phthalocyanine compound and a hydroxygallium phthalocyanine compound.
Furthermore, titanyl phthalocyanine Y type and A type (β type)
For example, a titanyl phthalocyanine compound having a main peak at a Bragg angle 2θ with respect to Cu-Kα characteristic X-rays (wavelength 1.54 °) is preferable. These oxytitanyl phthalocyanines are described in JP-A-10-69107. These charge generating substances may be used alone or in combination of two or more, for example, Y type and A type, or may be used by mixing with a polycyclic quinone such as a perylene pigment.

As the binder resin for the charge generation layer, known resins can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, Epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin,
Melamine resin, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin) and poly-vinyl carbazole resin And the like, but are not limited to these.

The charge generating layer is formed by dispersing a charge generating substance in a solution in which a binder resin is dissolved in a solvent using a dispersing machine to prepare a coating solution, and applying the coating solution to a constant film thickness by the coating machine. Then, it is preferable to produce the coating film by drying.

As a solvent for dissolving and applying the binder resin used for the charge generation layer, for example, toluene,
Xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolan, pyridine and diethylamine And the like, but are not limited thereto.

As a means for dispersing the charge generating substance, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, and the like can be used, but are not limited thereto.

Examples of the coater for forming the charge generating layer include a dip coater and a ring coater, but are not limited thereto.

The mixing ratio of the charge generating substance to the binder resin is preferably from 1 to 600 parts, more preferably from 50 to 5 parts, based on 100 parts of the binder resin.
00 parts. The thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 0.01 to 5 μm.

<< Charge Transport Layer >> The charge transport layer of the present invention contains a charge transport material and a binder resin, and is formed by dissolving and applying the charge transport material in a binder resin solution.

The charge transport material is disclosed in Japanese Patent Application No. 2000-3609.
No. 98, other than the charge-transporting materials mentioned in the general formula,
For example, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benz Imidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9 -Two or more kinds of vinyl anthracene may be mixed and used.

As the binder resin for the charge transport layer, known resins can be used. Polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic acid ester resin and styrene -Methacrylic acid ester copolymer resin, etc., and polycarbonate is preferable. Furthermore, BPA, BPZ, dimethyl BP
A, a BPA-dimethyl BPA copolymer and the like are preferred in view of cracking and abrasion charging characteristics.

The charge transport layer can be formed by dissolving a binder resin and a charge transport material to prepare a coating solution, applying the coating solution to a constant thickness by a coating machine, and drying the coating film. preferable.

Solvents for dissolving the binder resin and the charge transport material include, for example, toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, Butanol, tetrahydrofuran, 1,4-dioxane,
Examples include, but are not limited to, 1,3-dioxolane, pyridine, diethylamine, and the like.

The mixing ratio of the charge transporting substance to the binder resin is preferably 10 to 500 parts, more preferably 20 to 500 parts, based on 100 parts of the binder resin.
100 copies.

The thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin, the mixing ratio and the like, but is preferably 10 to 100 μm, and more preferably 1 to 100 μm.
5 to 40 μm. An AO agent (antioxidant), an EA agent (electron acceptor), a stabilizer and the like may be added to the charge transport layer. About AO agent, Japanese Patent Application No. 11-200135
And EA agents are disclosed in JP-A-50-137543 and JP-A-58-7.
No. 6483 is preferable.

<< Protective Layer >> To improve durability, a protective layer may be provided on the charge transport layer. As the binder resin for the protective layer, a known resin can be used, and a polycarbonate resin, a polyacrylate resin, a polyester resin, a polystyrene resin, a styrene-acrylonitrile copolymer resin, a polymethacrylate resin, and a styrene-methacrylate copolymer are used. Coalescing resin and the like. JP-A Nos. 9-190004 and 10-95787,
A siloxane-based resin described in 000-171990 is also good. << Toner >> As a result of extensive studies, the present inventors have solved the above problem by using a toner having a shape coefficient variation coefficient of 16% or less and a number variation coefficient in the number particle size distribution of 27% or less. I found that I can do it. That is, by making the shape distribution of the toner itself uniform, the distribution of the amount of charge at the time of transfer can be narrowed, the occurrence of image defects can be prevented, and the image quality can be improved.

Further, as a result of further investigations by the present inventors, the toner particles having no corners have no excessive charge accumulation due to the smoothness of the surface thereof. We found that it was effective. That is, it has been found that the problem of the present invention can be solved by using a toner in which the number of toner particles having no corners is 50% by number or more and the number variation coefficient in the number particle size distribution is 27% or less.

Further, as a result of the study by the present inventors, it has been found that even when the specific shape is made uniform, the chargeability of the toner can be made uniform and the same effect can be exhibited. That is, the problem of the present invention is solved by using a toner in which the number of toner particles having a shape coefficient in the range of 1.2 to 1.6 is 65% by number or more and the variation coefficient of the shape coefficient is 16% or less. I found that I can do it.

As a result of examining the charge amount distribution of the toner, in order to make the charge amount distribution of the toner extremely sharp, the variation in the particle size of the toner particles is controlled to be small, and the variation in the shape is also controlled to be small. It turned out to be necessary. By making the charge amount distribution of the toner extremely sharp, even when the toner charge amount is set low, stable chargeability can be obtained over a long period of time, and improved image quality can be maintained.

As a result of examination from the above viewpoints, the use of toner having a shape coefficient variation coefficient of 16% or less and a number variation coefficient of 27% or less in the number particle size distribution makes it possible to obtain the character dust and color shift. The present inventors have found that a high-quality image free of occurrence of an image can be formed for a long period of time, and have completed the present invention.

The inventors of the present invention have focused on the minute shape of each toner particle, and as a result, the shape of the corner portion of the toner particle has changed inside the developing device, and the shape has become round. Was found to be causing contamination.
Although the reason for this is not clear, it was presumed that stress was likely to be applied to the corners, which would change the chargeability of the toner. Further, when electric charge is applied to the toner particles by frictional charging, it is presumed that the electric charge tends to be concentrated particularly in the corner portions, and the electric charge of the toner particles tends to be uneven.

That is, even if the toner particles having no corners are set to 50% by number or more and the number variation coefficient in the number and particle size distribution is controlled to 27% or less, a high-quality image free from occurrence of character dust and color shift can be obtained. They have found that they can be formed over a long period of time, and have completed the present invention.

Further, it was also found that the charge amount distribution was sharp when the toner was made to have a specific shape and the shape was made uniform. That is, the use of a toner having a shape coefficient of 1.2% to 1.6% of toner particles in a range of 65% by number or more and a variation coefficient of the shape coefficient of 16% or less can also reduce the occurrence of character dust and color shift. The inventors have found that a high-quality image free of generation can be formed for a long period of time, and have completed the present invention.

The shape factor of the toner of the present invention is represented by the following equation, and indicates the degree of roundness of the toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projected area Here, the maximum diameter is defined as a parallel line when a projected image of a toner particle on a plane is sandwiched between two parallel lines. Means the width of the particle at which the distance between the particles becomes maximum. The projection area refers to the area of the projected image of the toner particles on the plane.

In the present invention, the shape factor is determined by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and referring to the “SCCANNING” based on the photograph.
The measurement was performed by analyzing a photographic image using "IMAGE ANALYZER" (manufactured by JEOL Ltd.). In this case, the shape factor of the present invention was measured by using the above formula using 100 toner particles.

In the present invention, the shape factor is 1.0
The content of the toner particles in the range of ~ 1.6 is preferably at least 65% by number, more preferably at least 70% by number. More preferably, the shape factor is 1.2 to 1.
The number of toner particles in the range of 6 is 65% by number or more, more preferably 70% by number or more.

When the number of toner particles having a shape coefficient in the range of 1.0 to 1.6 is at least 65% by number, excessively charged toner does not accumulate, and problems such as development ghosts hardly occur. . Further, the toner particles are hardly crushed, and the chargeability of the toner is stabilized.

The method for controlling the shape factor is not particularly limited. For example, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of adding a toner particle in a solvent that does not dissolve a toner to give a swirling flow, etc. To prepare a toner having a shape factor of 1.0 to 1.6 or 1.2 to 1.6, and then add it to a normal toner so as to fall within the range of the present invention. There is. Further, the whole shape is controlled at the stage of preparing a so-called polymerization toner, and the shape factor is set to 1.0 to 1.6,
Alternatively, there is a method of preparing a toner adjusted to 1.2 to 1.6.

Among the above methods, polymerization toners are preferred in that they are simple as a production method and that they have excellent surface uniformity as compared with pulverized toners.

The variation coefficient of the shape factor of the toner of the present invention is calculated from the following equation. Coefficient of variation = [S / K] × 100 (%) In the formula, S represents a standard deviation of the shape coefficient of 100 toner particles, and K represents an average value of the shape coefficient.

The variation coefficient of the shape factor is 16% or less, preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, the gap of the transferred toner layer is reduced, the fixing property is improved, and the offset is less likely to occur. Further, the charge amount distribution becomes sharp, and the image quality is improved.

In order to control the shape coefficient and the variation coefficient of the shape coefficient uniformly without extremely varying lots,
In the process of polymerizing, fusing, and controlling the shape of the resin particles (polymer particles), an appropriate process end time may be determined while monitoring the characteristics of the toner particles (colored particles) being formed.

The term “monitoring” means that a measuring device is incorporated in-line and the process conditions are controlled based on the measurement result. That is, for example, in the case of a polymerization toner formed by incorporating measurement of shape and the like in-line and associating or fusing resin particles in an aqueous medium, the shape and particle size are sequentially sampled in steps such as fusing. Is measured, and the reaction is stopped when the desired shape is obtained.

The monitoring method is not particularly limited, but a flow type particle image analyzer FPIA-
2000 (manufactured by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction site to constantly monitor and measure the shape and the like, and stop the reaction when the desired shape and the like are obtained.

The number particle size distribution and the number variation coefficient of the toner of the present invention are measured with a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter). In the present invention, a Coulter Multisizer was used by connecting an interface (manufactured by Nikkaki Co., Ltd.) for outputting a particle size distribution and a personal computer. The aperture used in the Coulter Multisizer is 100 μm and the aperture is 2 μm.
The volume and number of the above toners were measured to calculate the particle size distribution and the average particle size. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median size in the number particle size distribution.

The number variation coefficient in the number particle size distribution of the toner is calculated from the following equation. Number variation coefficient = (S / Dn) × 100 (%) where S represents a standard deviation in the number particle size distribution, and Dn
Indicates a number average particle size (μm).

The number variation coefficient of the toner of the present invention is 27% or less, preferably 25% or less. When the number variation coefficient is 27% or less, the gap of the transferred toner layer is reduced, the fixing property is improved, and the offset is less likely to occur. Further, the charge amount distribution is sharpened, the transfer efficiency is increased, and the image quality is improved.

The method of controlling the number variation coefficient of the present invention is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for further reducing the number variation coefficient. As a method of classifying in a liquid, there is a method of separating and collecting toner particles according to a sedimentation speed difference caused by a difference in toner particle diameter by controlling a rotation speed by using a centrifugal separator.

In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to reduce the number variation coefficient in the number particle size distribution to 27% or less. In the suspension polymerization method,
Before polymerization, it is necessary to disperse the polymerizable monomer in an aqueous medium into oil droplets of a desired size as a toner. In other words, mechanical shearing by a homomixer, a homogenizer, or the like is repeated on a large oil droplet of the polymerizable monomer to reduce the oil droplet to the size of toner particles. In the method by a gentle shear, the number and particle size distribution of the obtained oil droplets becomes broad, and therefore,
The particle size distribution of the toner obtained by polymerizing this becomes wide. For this reason, a classification operation is required.

The toner particles having no corners according to the present invention are toner particles having substantially no protrusions on which electric charges are concentrated or protrusions which are easily worn by stress. The toner particles are called cornerless toner particles.
That is, as shown in FIGS. 1A, 1B, and 1C,
A circle having a major axis of toner particles L and a radius R of L / 10,
When the inside is rolled while contacting the inside at one point with respect to the toner particle peripheral line, a case where a circle does not substantially extend outside the toner is called a toner particle having no corner. The case where the protrusion does not substantially protrude means that one or more protrusions have a protruding circle. Further, the major axis of the toner particle is defined as the projected image of the toner particle on the plane interposed between two parallel lines,
The width of the particle at which the interval between the parallel lines is maximum.

The measurement of the toner having no corner was performed as follows. First, a photograph in which toner particles are enlarged by a scanning electron microscope is taken, and further enlarged to obtain a photographic image of 15,000 times. Next, the presence or absence of the corners is measured for this photographic image. This measurement was performed for 100 toner particles.

In the toner of the present invention, the proportion of toner particles having no corners is at least 50% by number, preferably at least 70% by number. When the ratio of the toner particles having no corners is 50% by number or more, generation of fine particles and the like due to stress with the developer conveying member and the like are less likely to occur,
It is possible to prevent so-called excessively adherent toner from being adhered to the surface of the developer transport member, to suppress contamination of the developer transport member, and to sharpen the charge amount. In addition, the amount of toner particles that are easily worn or broken and the number of toner particles having a portion where charges are concentrated are reduced, the charge amount distribution is sharpened, the chargeability is stabilized, and good image quality can be formed over a long period of time.

The method for obtaining a toner having no corners is not particularly limited. For example, as described above, as a method of controlling the shape coefficient, a method of spraying toner particles into a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of dissolving a toner It can be obtained by adding to a solvent that does not contain and giving a swirling flow.

In a polymerization toner formed by associating or fusing resin particles, the surface of the fused particles has many irregularities at the stage of stopping the fusion, and the surface is not smooth. By setting conditions such as the temperature, the number of rotations of the stirring blade, and the stirring time, toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles.For example, at a temperature equal to or higher than the glass transition temperature of the resin particles, by setting a higher rotation speed,
The surface becomes smooth, and toner without corners can be formed.

The toner of the present invention preferably has a number average particle diameter of 3 to 8 μm. When toner particles are formed by a polymerization method, the particle diameter can be controlled by the concentration of the coagulant, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.

When the number average particle diameter is 3 to 8 μm, the presence of toner having excessively high adhesion to the developer conveying member or toner having low adhesion to the developer conveying member can be reduced in the fixing step. In addition to being able to stabilize for a long period of time, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

In the toner of the present invention, when the particle size of the toner particles is D (μm), the natural logarithm InD is plotted on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the particle size distribution, the sum (M1) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the class having the second highest frequency after the most frequent class. ) Is preferably 70% or more. The relative frequency (m1) and the relative frequency (m
When the sum (M) with 2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, by using the toner in the image forming step, it is possible to reliably suppress the occurrence of the selective development. it can.

In the present invention, the histogram showing the number-based particle size distribution is obtained by plotting a natural logarithm lnD (D: particle size of individual toner particles) at intervals of 0.23 in a plurality of classes (0 to 0).
0.23: 0.23 to 0.46: 0.46 to 0.69:
0.69 to 0.92: 0.92 to 1.15: 1.15
1.38: 1.38 to 1.61: 1.61 to 1.84:
1.84 to 2.07: 2.07 to 2.30: 2.30 to
(2.53: 2.53 to 2.76...) (In the above class, for example, 0.23 to 0.46 is 0.23 or more;
(Meaning less than 46) is a histogram showing the number-based particle size distribution divided by the Coulter Multisizer through the I / O unit according to the following conditions. The program is transferred to a computer and created by the computer using a particle size distribution analysis program.

Measurement conditions (1) Aperture: 100 μm (2) Sample preparation method: electrolytic solution [ISOTON R-1
1 (manufactured by Coulter Scientific Japan)
An appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml, and the mixture is stirred, and 10 to 20 mg of a measurement sample is added thereto. This system is prepared by subjecting it to a dispersion treatment with an ultrasonic disperser for 1 minute.

Next, regarding the numerical values according to the present invention, numerical values of conventionally known toners will be described. This value differs depending on the manufacturing method.

In the case of the pulverized toner, the shape factor is 1.2 to
The ratio of the 1.6 toner particles is about 60% by number. The variation coefficient of the shape factor is about 20%. Further, in the pulverization method, in order to reduce the particle size while repeating crushing, the toner particles have many corners, and the ratio of toner particles having no corners is 30% by number or less. Therefore,
In order to obtain a rounded toner having no corners and a uniform shape, it is necessary to perform a process of forming a spherical shape by heat or the like as described above as a method of controlling the shape coefficient. In addition, the number variation coefficient in the number particle size distribution is about 30% when the classification operation after the pulverization is performed once, and the classification operation needs to be further repeated to reduce the number variation coefficient to 27% or less. There is.

In the case of the toner obtained by the suspension polymerization method, the toner is conventionally polymerized in a laminar flow, so that substantially spherical toner particles are obtained. For example, in the case of the toner described in JP-A-56-130762, The proportion of toner particles having a coefficient of 1.2 to 1.6 is about 20% by number, the variation coefficient of the shape coefficient is also about 18%, and the proportion of toner particles having no corners is also about 85% by number. Further, as described above in the method for controlling the number variation coefficient in the number particle size distribution, mechanical shearing is repeated for a large oil droplet of a polymerizable monomer to reduce the oil droplet to a size of a toner particle. Therefore, the distribution of the oil droplet diameters is widened, and the particle size distribution of the obtained toner is wide, and the coefficient of number variation is as large as about 32%. If the toner is produced based on the classification, a classification operation is required.

Polymerized toners formed by associating or fusing resin particles are described in, for example, JP-A-63-163.
In the toner described in JP-A-186253, the ratio of the toner particles having a shape coefficient of 1.2 to 1.6 is 60% by number.
The variation coefficient of the shape factor is about 18%, and the ratio of toner particles without corners is about 44% by number. Further, the particle size distribution of the toner is wide and the number variation coefficient is 30%, and a classification operation is required to reduce the number variation coefficient.

The toner of the present invention is prepared by a suspension polymerization method or emulsion polymerization of a monomer in a liquid to which an emulsion of necessary additives is added.
It can be produced by a method of producing fine polymer particles, and then adding an organic solvent, a coagulant and the like to associate. A method of preparing by mixing and associating with a dispersion liquid such as a release agent or a colorant necessary for the composition of the toner at the time of association, or dispersing a toner component such as a release agent or a colorant in a monomer. And then emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

Incidentally, the aqueous medium in the present invention means a medium containing at least 50% by mass of water.

That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, and an ultrasonic disperser are added. Various constituent materials are dissolved or dispersed in the polymerizable monomer by a machine or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets of a desired size as a toner using a homomixer, a homogenizer, or the like. Thereafter, the stirring mechanism is moved to a reaction device, which is a stirring blade described later, and heated to cause the polymerization reaction to proceed. After completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying.

As a method of producing the toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can also be mentioned. Although this method is not particularly limited, for example, Japanese Unexamined Patent Application Publication No. 5-26525
No. 2, Japanese Unexamined Patent Publication No. 6-329947, Japanese Unexamined Patent Publication No.
No. 15904 can be mentioned.

A method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant, or a plurality of fine particles composed of a resin and a colorant, particularly by dispersing them in water using an emulsifier, At the same time as adding a coagulant over the concentration and salting out, the formed polymer itself is heated and fused at the glass transition temperature or higher to gradually grow the particle size while forming fused particles. At that point, a large amount of water was added to stop the growth of the particle size, and further heating and stirring were performed to smooth the surface of the particles while controlling the shape, and the particles were heated and dried in a fluid state while still containing water.
The toner of the present invention can be formed. Here, an organic solvent that is infinitely soluble in water may be added together with the coagulant.

As the polymerizable monomer constituting the resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Dimethylstyrene, p-tert-butylstyrene, p
-N-hexylstyrene, pn-octylstyrene,
pn-nonylstyrene, pn-decylstyrene, p
Styrene or a styrene derivative such as -n-dodecylstyrene, methyl methacrylate, ethyl methacrylate,
N-butyl methacrylate, isopropyl methacrylate,
Methacrylate derivatives such as isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate. , Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate,
N-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, acrylate derivatives such as phenyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, Vinyl fluoride,
Halogen vinyls such as vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc. Vinyl ketones, N-vinyl carbazole, N-vinyl indole,
There are N-vinyl compounds such as N-vinylpyrrolidone, vinyl compounds such as vinylnaphthalene and vinylpyridine, and acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide. These vinyl monomers can be used alone or in combination.

It is more preferable to use a polymerizable monomer constituting the resin in combination with one having an ionic dissociation group. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of a monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid. Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl methacrylate, 3
-Chloro-2-acid phosphooxypropyl methacrylate and the like.

Further, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. Can be used as a crosslinked resin.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As the oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo or diazo polymerization initiators such as nitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide , Dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-
Examples thereof include peroxide-based polymerization initiators such as (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in a side chain. .

When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. As the water-soluble radical polymerization initiator, potassium persulfate, persulfates such as ammonium persulfate, azobisaminodipropane acetate,
Azobiscyanovaleric acid and salts thereof, hydrogen peroxide and the like can be mentioned.

The dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, and calcium sulfate. , Barium sulfate,
Bentonite, silica, alumina and the like can be mentioned. Further, a surfactant generally used as a surfactant such as polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as a dispersion stabilizer.

As the resin excellent in the present invention, a resin having a glass transition point of 20 to 90 ° C. is preferable and a softening point of 8
The thing of 0-220 ° C is preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Furthermore, these resins have a number average molecular weight (Mn) of 10 as measured by gel permeation chromatography.
00 to 100000, weight average molecular weight (Mw) 200
Those having 0 to 1,000,000 are preferred. Further, as a molecular weight distribution, Mw / Mn is 1.5 to 100, particularly 1.8.
-70 are preferred.

The coagulant to be used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, a salt of an alkali metal such as sodium, potassium, and lithium, and as a divalent metal, for example, a salt of an alkaline earth metal such as calcium and magnesium, or a divalent metal such as manganese or copper Salt,
Examples include salts of trivalent metals such as iron and aluminum, and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Can be.
These may be used in combination.

The toner of the present invention contains at least a resin and a colorant, but may also contain a releasing agent or a charge control agent as a fixing property improving agent, if necessary. Further, an external additive composed of inorganic fine particles, organic fine particles, and the like may be added to the toner particles containing the resin and the colorant as main components.

As the colorant used in the toner of the present invention, carbon black, magnetic substance, dye, pigment and the like can be used arbitrarily. As the carbon black, channel black, furnace black, acetylene black, and the like can be used.
Thermal black, lamp black and the like are used. Ferromagnetic metals such as iron, nickel, and cobalt as magnetic materials,
Alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but show ferromagnetism by heat treatment, such as manganese-copper-
An alloy of a type called a Heusler alloy such as aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, 79, 81, 82, 93, 98, 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5,
48: 1, 53: 1, 57: 1, 122, 1
39, 144, 149, 166, 177, 1
78, 222, C.I. I. Pigment Orange 31, 43 and C.I. I. Pigment Yellow 14, 17, and 9
3, 94, 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60 and the like, and mixtures thereof can also be used. The number average primary particle size varies depending on the type, but
About 200 nm is preferable.

As a method of adding a colorant, a method of adding polymer particles prepared by an emulsion polymerization method at the stage of coagulation by adding a coagulant to color the polymer, or a process of polymerizing monomers. And a method of adding a colorant, polymerizing, and forming colored particles can be used. When the colorant is added at the stage of preparing the polymer, it is preferable to use the colorant after treating the surface with a coupling agent or the like so as not to inhibit the radical polymerizability.

Further, a low molecular weight polypropylene (number average molecular weight = 1500 to 9000), a low molecular weight polyethylene or the like may be added as a fixing property improving agent.

The charge control agents are also various known ones.
What can be dispersed in water can also be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof. The particles of the charge control agent and the fixability improving agent preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.

In a suspension polymerization method toner in which a toner component such as a colorant is dispersed or dissolved in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized to obtain a toner, a polymerization reaction is performed. By controlling the flow of the medium in the reaction vessel, the shape of the toner particles can be controlled. That is, when a large number of toner particles having a shape factor of 1.2 or more are formed, the flow of the medium in the reaction vessel is made turbulent, and the polymerization proceeds to be present in the aqueous medium in a suspended state. When the oil droplets gradually become polymerized, the oil droplets become soft particles, and when the oil droplets collide, the particles collide to promote the coalescence of the particles, resulting in particles with an irregular shape . When spherical toner particles having a shape factor smaller than 1.2 are formed, spherical particles can be obtained by using a medium flow in the reaction vessel as a laminar flow to avoid collision of the particles. By this method, the distribution of the toner shape can be controlled within the scope of the present invention.

In the suspension polymerization method, by using a specific stirring blade, a turbulent flow can be formed, and the shape can be easily controlled.

On the other hand, in the case of a polymerization toner in which resin particles are associated or fused in an aqueous medium, the flow and temperature distribution of the medium in the reaction vessel at the fusion stage are controlled to further improve the shape after fusion. By controlling the heating temperature, the number of rotations for stirring, and the time in the control step, the shape distribution and shape of the entire toner can be arbitrarily changed.

In the case of a polymerization toner for associating or fusing resin particles, the flow in the reactor is made laminar, and the agitating blade and the agitating tank capable of making the internal temperature distribution uniform are used. By controlling the temperature, the number of revolutions, and the time in the shape control step, it is possible to form a toner having a shape factor and a uniform shape distribution according to the present invention.

Further, in the toner of the present invention, more effects can be exhibited by adding and using fine particles such as inorganic fine particles and organic fine particles as an external additive. The reason for this is presumed that the embedding and detachment of the external additive can be effectively suppressed, so that the effect is remarkable.

As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania, and alumina. Further, it is preferable that these inorganic fine particles have been subjected to a hydrophobic treatment with a silane coupling agent or a titanium coupling agent. preferable.

The amount of the external additive to be added is 0.1 to 5.0% by mass, preferably 0.5 to 4.0% by mass in the toner. Various external additives may be used in combination.

As a preferred fixing method used in the present invention, a so-called contact heating method can be used. In particular, examples of the contact heating method include a heat and pressure fixing method, a heat roller fixing method, and a pressure heat fixing method in which fixing is performed by a rotating pressing member including a fixedly disposed heating element.

FIG. 4 is a sectional view of an image forming apparatus as an example of the image forming method of the present invention. In FIG. 4, reference numeral 50 denotes a photoreceptor drum (photoreceptor) serving as an image bearing member, which is a photoreceptor having an organic photosensitive layer applied on the drum and a surface layer of the present invention applied thereon. It is driven and rotated clockwise. 52
Is a scorotron charger (charging means) for uniformly charging the peripheral surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, in order to eliminate the history of the photoconductor in the previous image formation, exposure by the pre-charging exposure unit 51 using a light emitting diode or the like may be performed to remove the charge on the peripheral surface of the photoconductor.

After the photosensitive member is uniformly charged, an image exposing device (image exposing means) 53 performs image exposure based on the image signal. The image exposure device 53 in this figure uses a laser diode (not shown) as an exposure light source. Rotating polygon mirror 53
1. The light on the photosensitive drum is scanned by the light whose optical path is bent by the reflection mirror 532 via the fθ lens and the like, and an electrostatic latent image is formed.

Here, the reversal development of the present invention means that the surface of the photosensitive member is uniformly charged by the charger 52, and the region where image exposure has been performed, that is, the exposed portion potential (exposed portion region) of the photosensitive member is developed. Is an image forming method for visualizing the image. On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.

The electrostatic latent image is then developed (developing means)
Developed at. A developing device 54 containing a developer including a toner and a carrier is provided on the periphery of the photoreceptor drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer stirring / conveying members 544 and 543, a conveyance amount regulating member 542, and the like. The developer is agitated and conveyed to be supplied to the developing sleeve. Controlled by member 542. The transport amount of the developer varies depending on the linear velocity of the applied electrophotographic photosensitive member and the specific gravity of the developer, but is generally 20 to 200 m.
g / cm ² .

The developer includes, for example, a carrier having ferrite as a core and an insulating resin coated around the core, a colorant such as carbon black, a charge control agent, and a low molecular weight compound according to the present invention. The toner is composed of a toner in which silica, titanium oxide, or the like is externally added to colored particles of polyolefin, and the developer is transported to a development area with the layer thickness regulated by a transport amount regulating member, where development is performed. At this time, usually, the photosensitive drum 50
The development is performed by applying a DC bias and an AC bias voltage if necessary between the developing sleeve 541 and the developing sleeve 541. The developer is developed in a state of contact or non-contact with the photoconductor. To measure the potential of the photoconductor, the potential sensor 547 is used as shown in FIG.
As described above.

After the image is formed, the recording paper P is fed to the transfer area by the rotation of the paper feed roller 57 at the time when the transfer timing is adjusted.

In the transfer area, the toner on the photoreceptor is transferred to the fed recording paper P by a transfer electrode (transfer means) 58 which applies a charge of the opposite polarity to the toner.

Next, the recording paper P is separated from the separation electrode (separation means) 5.
9, the toner is removed from the peripheral surface of the photosensitive drum 50, conveyed to a fixing device (fixing unit) 60, and heated and pressed by the heat roller 601 and the pressure roller 602 to fuse the toner and then discharge the paper 61. Is discharged out of the apparatus via The transfer electrode 58 and the separation electrode 59 are retracted and separated from the peripheral surface of the photosensitive drum 50 after the recording paper P has passed to prepare for the formation of the next toner image.

On the other hand, the photosensitive drum 50 from which the recording paper P has been separated removes and cleans the residual toner by pressing the blade 621 of the cleaning device (cleaning means) 62.
Upon receiving the charge elimination by the pre-charge exposure unit 51 and the charging by the charger 52 again, the image forming process starts.

Reference numeral 70 denotes a detachable process cartridge in which a photosensitive member, a charger, a transfer device, a separator, and a cleaning device are integrated.

The image forming method and the image forming apparatus of the present invention are applicable to general electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers. , Light printing, plate making and facsimile.

[0174]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 (Toner 1: Example of Emulsion Polymerization Association Method) 0.90 kg of sodium n-dodecyl sulfate and 10.0 L of pure water are put and dissolved by stirring. To this solution, 1.20 kg of Regal 330R (carbon black, manufactured by Cabot Corporation) was gradually added, and the mixture was stirred well for 1 hour, and then continuously dispersed for 20 hours using a sand grinder (medium type disperser). This is referred to as “colorant dispersion liquid 1”. Also, 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 L of ion-exchanged water were used.
Is referred to as “anionic surfactant solution A”.

Nonylphenol polyethylene oxide 10 mol adduct 0.014 kg and ion exchanged water 4.0 L
Is referred to as “nonionic surfactant solution B”.
223.8 g of potassium persulfate was added to 12.0 L of deionized water.
Is referred to as "initiator solution C".

A stirring tank having a stirring blade which can be preferably used in the present invention will be described with reference to the drawings. FIG.
Is an example of a stirring tank provided with stirring blades. A rotating shaft 3 is suspended from the center of a vertical cylindrical stirring tank 2 having a heat exchange jacket 1 mounted on the outer periphery of the stirring tank, and the rotating shaft 3 is brought close to the bottom surface of the stirring tank 2. A lower stirring blade 4 disposed;
There is a stirring blade 5 arranged at an upper stage. Upper stage stirring blade 5
Is disposed at an intersection angle α that precedes the stirring blade 4 located in the lower stage in the rotation direction. In the present invention, the intersection angle α is preferably less than 90 degrees (°). The lower limit of the crossing angle is not particularly limited, but is preferably about 5 degrees or more, and more preferably 10 degrees or more.

With this configuration, the medium is first stirred by the stirring blades arranged in the upper stage, and a flow to the lower side is formed. Then, by the stirring blade arranged in the lower stage,
It is presumed that the flow formed by the upper stirring blade is further accelerated downward, and a downward flow is separately formed by the stirring blade itself, so that the flow is accelerated and proceeds as a whole. As a result, it is presumed that a basin having a large shear stress formed as a turbulent flow is formed, so that the shape of the toner can be controlled.

The shape of the stirring blade is not particularly limited, but may be a square plate, a notch in a part of the blade, and one or more middle holes, so-called slits, in the center. Things and the like can be used. These examples are described in FIG. In FIG. 3, (a) shows a stirring blade without a hole, (b) a large hole 6 at the center, (c) a horizontally long hole 6, and (d). There is a vertically long middle hole 6. Further, these may be different from each other in the upper hole and the lower hole, or may be the same.

In FIG. 2, the arrow indicates the rotation direction, 7 indicates the upper material inlet, and 8 indicates the lower material inlet.

A 100 L GL (glass lining) reactor equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device was charged with W
3.41 kg of AX emulsion (polypropylene emulsion having a number average molecular weight of 3,000: number average primary particle size = 120 nm / solid concentration = 29.9%), the whole amount of “anionic surfactant solution A” and “nonionic surfactant solution B” Add the whole amount and start stirring. The configuration of the stirring blade was the configuration shown in FIG. The angle and the overall size of the stirring blade are shown in a separate table. Next, 44.0 L of ion-exchanged water is added.

Heating was started, and when the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Then, while controlling the liquid temperature to 75 ° C. ± 1 ° C., the styrene 1
2.1 kg, n-butyl acrylate 2.88 kg, methacrylic acid 1.04 kg and t-dodecyl mercaptan 54
8 g are added dropwise. After completion of the dropwise addition, the temperature of the solution was raised to 80 ° C. ± 1 ° C., and the mixture was heated and stirred for 6 hours. Next, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and the mixture was filtered with a pole filter to obtain “latex-A”.

The resin particles in the latex-A had a glass transition temperature of 57 ° C., a softening point of 121 ° C., a molecular weight distribution of weight average molecular weight = 1270,000 and a weight average particle diameter of 12
It was 0 nm.

A solution obtained by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 L of ion-exchanged pure water is referred to as “anionic surfactant solution D”. Also,
A solution prepared by dissolving 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct in 4.0 L of ion-exchanged water is referred to as “nonionic surfactant solution E”.

Potassium persulfate (Kanto Chemical) 200.
A solution obtained by dissolving 7 g in 12.0 L of ion-exchanged water is referred to as “initiator solution F”.

A 100-L GL reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle (the structure of the stirring blade is shown in FIG. 3A) was mixed with a wax emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average). (Primary particle size = 120 nm / solids concentration 29.9%) 3.41
kg, the entire amount of “anionic surfactant solution D” and the entire amount of “nonionic surfactant solution E” are added, and stirring is started. Next, 44.0 L of ion-exchanged water is charged. Heating is started, and when the liquid temperature reaches 70 ° C., “Initiator solution F” is added. Then, 11.0 kg of styrene, 4.00 kg of n-butyl acrylate and 1.04 methacrylic acid were used.
kg and 9.02 g of t-dodecylmercaptan are added dropwise. After the completion of dropping, the temperature of
The mixture was heated and stirred for 6 hours while controlling at 2 ° C. ± 2 ° C. Further, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature is cooled to 40 ° C. or less, and the stirring is stopped. The solution was filtered through a Pall filter, and this filtrate was designated as "latex-B".

The glass transition temperature of the resin particles in latex-B was 58 ° C., the softening point was 132 ° C., and the molecular weight distribution was weight average molecular weight = 245,000 and mass average particle size was 11
It was 0 nm.

Sodium chloride as salting-out agent 5.36k
g in ion-exchanged water 20.0 L is referred to as “sodium chloride solution G”.

A solution obtained by dissolving 1.00 g of a fluorinated nonionic surfactant in 1.00 L of ion-exchanged water is referred to as "nonionic surfactant solution H". 100L SUS reactor equipped with temperature sensor, cooling tube, nitrogen introduction device, particle size and shape monitoring device (Fig. 3 (a) shows the configuration of the stirring blade)
In addition, latex-A = 20.0 kg, latex-B = 5.2 kg, and colorant dispersion 1 = 0.
4 kg and 20.0 kg of ion-exchanged water are added and stirred.
Then, the mixture is heated to 40 ° C., and sodium chloride solution G, 6.00 kg of isopropanol (manufactured by Kanto Chemical Co., Ltd.) and nonionic surfactant solution H are added in this order. Then, after leaving it to stand for 10 minutes, the temperature is raised and the temperature is raised to 85 ° C. by 60 ° C.
The temperature is raised in minutes and heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours to grow the particle size while salting out / fusing. Next, pure water2.
Add 1 L to stop grain size growth.

In a 5 L reaction vessel equipped with a temperature sensor, a cooling pipe, and a device for monitoring the particle size and shape (the structure of the stirring blade is shown in FIG. 2), 5.0 k of the fused particle dispersion prepared above was placed.
g was added and the mixture was heated and stirred at a liquid temperature of 85 ° C. ± 2 ° C. for 0.5 to 15 hours to control the shape. Thereafter, the mixture is cooled to 40 ° C. or less and the stirring is stopped. Next, classification is performed in the liquid by a centrifugal sedimentation method using a centrifugal separator, and the liquid is filtered through a sieve having openings of 45 μm, and the filtrate is used as an associated liquid. Next, non-spherical particles in the form of a wet cake were collected by filtration from the associated liquid using a Nutsche. Thereafter, the substrate was washed with ion-exchanged water.

The non-spherical particles were dried at a suction temperature of 60 ° C. using a flash jet drier, and then dried at a temperature of 60 ° C. using a fluidized bed drier. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain toner 1 by an emulsion polymerization association method.

In the monitoring of the salting-out / fusion step and the shape control step, the number of rotations of the stirring and the heating time are controlled to control the variation coefficient of the shape and the shape coefficient. And the coefficient of variation of the particle size distribution is arbitrarily adjusted to obtain toners 1-1 to 1 shown in Table 1.
1-5 was obtained. The composition is styrene / n-butyl acrylate / methacrylic acid = 0.758 / 0.162 / 0.08
0 mol%, Tg of the resin is about 57 ° C., and SP value is 1
0.04.

(Toner 2: Example of Emulsion Polymerization Association Method) As in the case of Toner 1, in the monitoring of the salting-out / fusion step and the shape control step, the shape and the shape are controlled by controlling the number of rotations of stirring and the heating time. The coefficient of variation of the coefficient was controlled, and the coefficient of variation of the particle size and the particle size distribution was arbitrarily adjusted by submerged classification to obtain Toner 2-1 shown in Table 1. The composition is styrene / n-butyl acrylate / methacrylic acid of toner 1 = 0.758 / 0.162 / 0.08.
From 0 mol%, styrene / n-butyl acrylate / n
-Butyl methacrylate = 0.87 / 0.035 / 0.
Changed to 095 mol%. The Tg of the resin was 67 ° C. and the SP value was 9.84.

(Toner 3: Example of Emulsion Polymerization Association Method) In the same manner as in toner 1, in the monitoring of the salting-out / fusion step and the shape control step, the shape and the shape are controlled by controlling the number of rotations of stirring and the heating time. The coefficient of variation of the coefficient is controlled, and the coefficient of variation of the particle size and the particle size distribution is arbitrarily adjusted by classification in a liquid.
2 was obtained. The composition is styrene / n-butyl acrylate / n-butyl methacrylate = 0.67 / 0.03 /
0.30 mol%. The SP value was 9.46.

(Production of Developer) Each of the toners 1-1 to 1-3-2 and a 45 μm ferrite carrier coated with a styrene-methacrylate copolymer are mixed at a ratio of 19.8 g and 200.2 g of the carrier, respectively. Thus, a developer for evaluation was manufactured.

[0196]

[Table 1]

Example 2 Intermediate layer dispersions of Examples of the present invention and Comparative Examples were prepared as follows. In the description, “parts” means “parts by mass”.

(Preparation of Intermediate Layer Dispersion Liquid 1) Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Titanium oxide SMT500SAS (manufactured by Teica; surface treatment: silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 0 parts methanol 10 parts The dispersion liquid was dispersed in a batch mode for 10 hours using a sand mill as a dispersing machine, to thereby prepare an intermediate layer dispersion liquid 1.

(Preparation of Intermediate Layer Dispersions 2 to 7) Titanium oxide and its surface treatment and particle size, binder resin, titanium oxide / binder resin mass ratio, solvent, and dispersion time were 10
~ 20 hours, except as shown in Table 2.
Intermediate layer dispersions 2 to 6 were prepared in the same manner as in the intermediate layer dispersion 1.

(Preparation of Intermediate Layer Dispersion 8) One part of polyamide resin CM8000 (manufactured by Toray Industries, Inc.) was mixed with 7 parts of methanol and 1-
It was added to and dissolved in a mixed solvent of 3 parts of propanol to prepare Interlayer Dispersion 8 (Comparative Example).

(Preparation of Intermediate Layer Dispersion 9) Intermediate layer dispersion 9 (Comparative Example) was prepared in the same manner as Intermediate Layer Dispersion 1 except that silica (Aerosil R805, Tegusa) was dispersed instead of titanium oxide. Produced.

Photoreceptor 1 The following intermediate layer dispersion coating solution 1 was prepared, applied on a washed cylindrical aluminum substrate by a dip coating method, and dried to a film thickness of 2 μm.
m of intermediate layers were formed.

<Intermediate Layer (UCL) Coating Solution> The intermediate layer dispersion 1 was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; Rigimesh filter manufactured by Nippon Pall Co., Ltd. Nominal filtration accuracy: 5 microns) , Pressure; 4.9033 Pa)
did.

The following coating solutions were mixed and dispersed using a sand mill to prepare a charge generating layer coating solution. This coating solution is applied by a dip coating method, and a dry film thickness of 0.3 μm is formed on the intermediate layer.
m of the charge generation layer was formed.

<Charge Generating Layer (CGL) Coating Solution> Y-type oxytitanyl phthalocyanine (the maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 27.3 at 2θ) 20 g polyvinyl butyral (# 6000-C, electricity 10 g t-butyl acetate 700 g 4-methoxy-4-methyl-2-pentanone 300 g The following coating solutions were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied on the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 24 μm, thereby producing a photoreceptor 1.

<Charge Transport Layer (CTL) Coating Solution> Charge transport agent (Compound A) 75 g Polycarbonate resin “Iupilon-Z300” (manufactured by Mitsubishi Gas Chemical Company) 100 g Methylene chloride 750 g

[0207]

Embedded image

Photoconductors 2 to 9 Photoconductors 2 to 9 were prepared in the same manner as photoconductor 1 except that intermediate layer dispersions 2 to 9 shown in Table 2 were used instead of intermediate layer dispersion 1 used for photoconductor 1. 2 to 9 were produced.

[0209]

[Table 2]

Photoreceptor 10 Photoreceptor 10 was prepared in the same manner as for photoreceptor 1, except that a cylindrical aluminum substrate subjected to anodizing and sealing was used as the substrate.

Evaluation The photosensitive members 1 to 10 obtained in Konica 7050 (laser digital copying machine manufactured by Konica Corporation: equipped with a cartridge in which the photosensitive member and a charger, a developing device, a cleaning device, and a static eliminator are integrated) were used. It was mounted and the following charging conditions and cleaning conditions were set. Table 3 shows the photoconductors and toners used in combination.

Charging condition Charging device: Initial charging potential is -650 V Development condition DC bias; -500 V Dsd (distance between photoconductor and developing sleeve); 600 μm Developer layer regulation; Magnetic H-Cut system Developer layer thickness: 700 μm Development Sleeve diameter: 40 mm Transfer pole: Corona charging method, transfer dummy current value: 45 μA Cleaning condition Elastic rubber blade; free length: 9 mm, thickness: 2 mm,
Hardness: 70 °, rebound resilience: 35, photosensitive member contact pressure (linear pressure): 15 g / cm (actual image evaluation)
Under the environment of 80 ° C. and 80% RH, the photosensitive layer thickness is 15 μm
Until, the actual copy was printed at a printing rate of 10% using A4 paper, and the fog, sharpness, image unevenness, black spots, etc. of the copied image were visually evaluated according to the following evaluation criteria.

In the evaluation, a character image having a pixel ratio of 7%, a portrait image of a person, a solid white image, and an original image in which a solid black image were each １ ／ equally divided were copied in A4.
The solid black image and the thin line image were evaluated.

In the crack test, the surface of the sample coated up to the intermediate layer was observed, and the presence or absence of cracks was checked. From this, a photoreceptor was formed, samples of various crack grades were obtained, 5000 copies were actually photographed, and cracks and the like not appearing in the image were converted, selected and evaluated.

Regarding fog, the absolute reflection density of each image was measured using RD-918 manufactured by Macbeth. As the rise in the residual potential increases, the image density decreases,
When the decrease in the charged potential is large, fog occurs. Further, when the uniformity of the charging potential is reduced, the image unevenness is increased.

On the other hand, the sharpness was visually determined by the number of fine lines per 1 mm that could be determined from the fifth generation copy image.

With respect to the black spots, the number of black spots having a major axis of 0.4 mm or more per A4 paper was determined. Incidentally, the length of the black spot is measured by a microscope equipped with a video printer.

Evaluation Criteria The criteria for each evaluation are as follows. Table 3 shows the obtained results.

Cracks 1: Cracks not appearing in the image remain as they are, and there is no practical problem. 2 ... Cracks appearing in the image slightly are practically used.
K3: cracks grow and grow, appear on the image, not practical.

Fog: Judgment based on solid white image density ・ ・ ・: 0.005 or less (good) ・ ・ ・: Larger than 0.005 and less than 0.01 (level that causes no practical problem) ×: 0.01 Above (practically problematic).

Sharpness: Judgment by fine line image ・ ・ ・: 8 lines / mm or more (good) ・ ・ ・: 6 lines / mm or more, 7 lines / mm or less (level that causes no problem in practical use) ×: 5 lines / mm mm or less (there is a problem in practice).

Image unevenness: Difference in density (Δ
HD = maximum density−minimum density) ◎ ・ ・ ・ 0.05 or less (good) ○ ・ ・ ・ More than 0.05 and less than 0.1 (level that causes no practical problem) × ・ ・ ・ 0.1 or more (There is a problem in practical use).

Black spots ・ ・ ・: Black spot frequency of 0.4 mm or more: all copied images are 3 / A4 or less ○: Black spot frequency of 0.4 mm or more: 4 / A4 or more, 19 / One or more sheets of A4 or less are generated (a level that does not cause a problem in practical use).... Frequency of black spots of 0.4 mm or more: 20 pieces / one or more sheets of A4 or more are generated (a problem occurs in practical use).

[0224]

[Table 3]

From Table 3, it can be seen that Experiment No. 1 in which the photosensitive member of the present invention and the toner of the present invention were combined. 1 to 8 are film thickness loss of 15 μm
m, with no black spots, reduced image density, fog, cracks, etc. under high temperature and high humidity environmental characteristics, and good adhesion to the lower layer, and can be used for a long time. is there. On the other hand, in Experiment No. 3 in which a photoreceptor outside the present invention and the toner of the present invention were combined. Experiment Nos. 9 and 10 combining the photoreceptor of the present invention with a toner other than the present invention. 11
And 12 show only poor results, as shown in Table 3.

[0226]

EFFECT OF THE INVENTION In combination with an intermediate layer to which N-type semiconductor particles are added, the film has a durability of 15 μm or more in film thickness loss, and particularly, black spots, reduced image density, fog, cracks and the like under high temperature and high humidity environmental characteristics No adhesion, good adhesion to the lower layer,
An image forming method, an image forming apparatus, and a process cartridge that can be used for a long time can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating toner particles having no corners.

FIG. 2 is a perspective view of an example of a stirring tank provided with the stirring blade of the present invention.

FIG. 3 is a schematic view of a shape of a stirring blade.

FIG. 4 is a sectional view of an image forming apparatus as an example of the image forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchange jacket 2 Stirring tank 3 Rotating shaft 4 Lower stirrer blade 5 Upper stirrer blade 6 Medium hole 7 Upper material input port 8 Lower material input port 50 Photoconductor drum (or photoconductor) 51 Exposure unit before charging 52 Charger 53 Image Exposure Device 54 Developing Device 541 Developing Sleeve 543, 544 Developer Agitating / Conveying Member 547 Potential Sensor 57 Feeding Roller 58 Transfer Electrode 59 Separating Electrode (Separator) 60 Fixing Device 61 Paper Discharge Roller 62 Cleaning Device 70 Process cartridge

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G03G 9/08 381 (72) Inventor Shinichi Hamaguchi 1 Konica Sakuracho, Hino City, Tokyo In-house F-term ( Reference) 2H005 AA01 AB06 CA04 EA05 EA10 2H068 AA21 AA43 AA44 BA58 BB28 CA06 CA29 CA33 CA60

Claims (22)

[Claims] 1. An image forming method comprising: rotating an electrophotographic photosensitive member having an intermediate layer between a conductive support and a photosensitive layer; and repeating at least charging, exposure, development with toner, and transfer, wherein the intermediate layer is an N-type. The toner contains semiconductor particles and a binder, and the toner has a shape coefficient variation coefficient of 16% or less and a number variation coefficient in a number particle size distribution of 27%.
An image forming method characterized by the following. 2. The image forming method according to claim 1, wherein the N-type semiconductor particles have a number average primary particle size of 10 nm or more and 200 nm or less. 3. The image forming method according to claim 1, wherein the N-type semiconductor particles are metal oxide particles. 4. The image forming method according to claim 1, wherein said N-type semiconductor particles are titanium oxide particles. 5. The method according to claim 4, wherein the titanium oxide particles have been subjected to a surface treatment a plurality of times, and the final surface treatment is a surface treatment with a reactive organosilicon compound.
3. The image forming method according to 1., 6. The image forming method according to claim 5, wherein the reactive organosilicon compound is methyl hydrogen polysiloxane. 7. The image forming method according to claim 5, wherein the reactive organic silicon compound is an organic silicon compound represented by the following general formula (1). General formula (1) R-Si- (X) ₃ (wherein, R represents an alkyl group or an aryl group, and X represents a methoxy group, an ethoxy group, or a halogen group.) 8. The compound of the general formula (1) wherein R has 4 to 8 carbon atoms.
The image forming method according to claim 7, wherein the alkyl group comprises 9. The method according to claim 5, wherein at least one of the plurality of surface treatments is a surface treatment of at least one compound selected from alumina, silica, and zirconia. The image forming method according to any one of the above items. 10. The method according to claim 4, wherein the titanium oxide particles are subjected to a surface treatment with silica or alumina and / or a surface treatment with a reactive organosilicon compound. Item. 11. The image forming method according to claim 4, wherein said titanium oxide particles have been subjected to a surface treatment with an organosilicon compound having a fluorine atom. 12. The image forming method according to claim 1, wherein the binder of the intermediate layer is a polyamide resin. 13. The toner according to claim 13, wherein the toner has a shape factor of 1.0 to 1.
The image forming method according to any one of claims 1 to 12, wherein the content of the toner particles in the range of 6 is 65% by number or more. 14. The toner according to claim 1, wherein the toner has a shape factor of 1.2 to 1.
The image forming method according to any one of claims 1 to 12, wherein the content of the toner particles in the range of 6 is 65% by number or more. 15. The toner according to claim 1, wherein the toner contains toner particles having no corners in an amount of 50% by number or more.
3. The image forming method according to any one of 2. 16. The number average particle diameter of the toner is 3 to 8 μm.
m.
Item. 17. When the particle size of the toner particles is D (μm), the natural logarithm lnD is plotted on the horizontal axis, and the horizontal axis shows the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class in the histogram and the relative frequency (m2) of the toner particles included in the class having the second highest frequency after the most frequent class is 70% or more. 2. The method according to claim 1, wherein
17. The image forming method according to any one of items 16 to 16. 18. The image forming method according to claim 1, wherein the toner is obtained from colored particles obtained by polymerizing at least a polymerizable monomer in an aqueous medium. . 19. The image forming method according to claim 1, wherein the toner is obtained from colored particles obtained by associating at least resin particles in an aqueous medium. 20. The toner according to claim 1, wherein the toner contains a styrene- (meth) acrylate resin.
20. The image forming method according to any one of items 19 to 19. 21. An image forming apparatus having at least a charging unit, an exposing unit, a developing unit, and a transferring unit around an electrophotographic photoreceptor and repeatedly forming an image, wherein the image forming method is any one of claims 1-20. An image forming apparatus according to any one of the preceding claims. 22. A process cartridge used in an image forming apparatus that has at least a charging unit, an exposing unit, a developing unit, and a transferring unit around an electrophotographic photosensitive member, and is used for an image forming apparatus that repeatedly forms an image. 21. The image forming apparatus according to claim 1, further comprising at least one of a unit, an exposing unit, a developing unit, a transferring unit, and a cleaning unit, configured to be able to be inserted into and removed from the image forming apparatus. A process cartridge used in an image forming method.