JP2003316051A - Organic photoreceptor, image forming method, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor improved in the transferability of toner and cleaning performance, further realizing the prevention of the occurrence of image blur and environmental memory, and improved in wear and abrasion resistance, and to provide an image forming apparatus and a process cartridge using the organic photoreceptor. <P>SOLUTION: The organic photoreceptor provided with at least a photoreceptive layer on a conductive supporting body is set so that its surface layer incorporates inorganic particles whose number average primary particle diameter is ≥1 nm and <100 nm, and humidity is adjusted under relative humidity environment being 80% at 20°C, and the endothermic energy variation ΔH of differential scanning thermal analysis measured in the range of 40 to 200°C is 0 to 10 J/g. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic photoconductor used in the field of copying machines and printers, an image forming method using the organic photoconductor, an image forming apparatus and a process cartridge.

[0002]

2. Description of the Related Art In recent years, an organic photoconductor containing an organic photoconductive substance has been most widely used as an electrophotographic photoconductor. Organic photoconductors are advantageous over other photoconductors because it is easy to develop materials for various exposure light sources from visible light to infrared light, materials that do not cause environmental pollution can be selected, and manufacturing costs are low. However, in particular, the organic photoconductor has a stable charge,
It has excellent potential holding properties and is most suitable for high resolution required in recent digitalization.

However, there are some problems required for the organic photoconductor in order to realize the high image quality. One of the problems is a problem related to toner cleaning property. An organic photoconductor (hereinafter also referred to as a photoconductor) tends to have a large adhesive force with a toner composed of the same organic substance, and removal of residual toner adhering to the surface of the photoconductor tends to be insufficient. In particular, when polymerized toner, which has been adopted for high image quality in recent years, is used, the adhesion of the toner to the surface of the photoconductor becomes high, and in a cleaning method using a rubber blade (hereinafter, blade cleaning), The phenomenon that "toner slips through" when the toner passes through the blade, "blade curl" when the blade is reversed, or friction noise between the photoconductor and the blade, that is, "blade squeal" occurs easily. Further, if the contact pressure of the blade with respect to the photoconductor is increased in order to solve the above-mentioned "toner slip-through", the organic photoconductor will be worn and the durability will be insufficient.

To solve the above problems, a method for improving the cleaning property of the residual toner on the organic photoconductor and the abrasion resistance of the organic photoconductor is disclosed in JP-A-56-117245.
No. 63-916666 and JP-A-1-205171.
It is described in each of the publications that hydrophobic silica can be contained in the outermost surface layer of the photoconductor to increase the mechanical strength of the photoconductor surface and improve the durability. Further, in JP-A-57-176057, JP-A-61-117558, JP-A-3-155558 and the like, hydrophobic silica particles obtained by treating the hydrophobic silica with a silane coupling agent or the like are used as photoreceptors. It is described that it is contained in the outermost surface layer to increase the mechanical strength of the photoconductor and impart lubricity to the photoconductor to obtain a photoconductor having higher durability.

Further, as a method for improving the above-mentioned insufficient hydrophobization of the hydrophobized silica particles, Japanese Patent Application No. 7-9957 discloses a technique of applying sintered silica to the surface layer of a photoreceptor. That is, in the differential scanning calorimetry analysis when the humidity is controlled in an environment of 80% relative humidity, the endothermic energy change amount ΔH in the range of 40 ° C. or higher and 200 ° C. or lower is 0 to 20 joules / g.
And a photosensitive body containing hydrophobic silica having a volume average particle size of 0.05 μm or more and 2 μm or less, and sinterable silica is used as the hydrophobic silica particles used in the photosensitive body. .

However, with respect to the high resolution required in the recent digitization, in the case of the photoconductor using the above-mentioned hydrophobized silica, minute fluctuations and variations in the potential of the photoconductor which have not been a problem in the past have been considered. Was faithfully reproduced in the image, and it was recognized as a new image defect. When the surface layer of the organic photoconductor contains the above-mentioned hydrophobic silica, abrasion property of the photoconductor and cleaning failure are improved, but image blur easily occurs under a high temperature and high humidity condition, or it is abrupt. When the humidity changes and the environment changes from high humidity to low humidity, a memory phenomenon (hereinafter, referred to as an environmental memory) that causes a black belt-shaped image defect in reversal development is caused. As a result of studying this phenomenon, the inventors of the present invention have found that the toner in the developer has a slower adaptation to the environment than the photoreceptor and peripheral members. We found that there was a humidity difference with other parts, which caused image blurring and environmental memory.

At the same time, it has been found that when such a photoreceptor is used repeatedly, the surface of the photoreceptor becomes rough and the image becomes rough. That is, by using the above-mentioned hydrophobic silica for the surface layer of the photoconductor, image blurring occurs, the humidity dependency of the photoconductor becomes larger, environmental memory occurs, and the surface wear due to cleaning or the like does not occur. It is considered that homogenization appears.

That is, even in the case of the hydrophobic silica as described above, the photosensitive layer has a built-in portion for adsorbing water molecules inside the silica and is less susceptible to humidity change, that is, the humidity is less likely to be taken into the photosensitive body. It is considered that the above configuration is necessary for solving the above-described image blurring, environmental memory, and the like.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. That is, the object of the present invention is to improve the transferability of toner, the cleaning property, and prevent the occurrence of image blur and environmental memory.
To provide an organic photoreceptor having improved wear resistance,
An object is to provide an image forming apparatus and a process cartridge using the organic photoconductor.

[0010]

As a result of intensive studies by the present inventors, it was found that the object of the present invention can be achieved by adopting any one of the following constitutions.

1. In an organic photoreceptor having at least a photosensitive layer provided on a conductive support, the surface layer of the organic photoreceptor contains inorganic particles having a number average primary particle diameter of 1 nm or more and less than 100 nm, and a relative temperature of 20 ° C. 80%. An organophotoreceptor characterized in that the amount of change in endothermic energy ΔH in differential scanning calorimetry measured in the range of 40 to 200 ° C. is 0 to 10 J / g, the humidity being controlled in a humidity environment.

2. In an organic photoreceptor having an intermediate layer, a charge generation layer, a charge transport layer and a surface layer on a conductive support, the surface layer has a number average primary particle diameter of 1 nm or more, 100
containing inorganic particles of less than nm, and conditioned under the relative humidity environment of 20 ° C. and 80%, and the endothermic energy change ΔH of the differential scanning calorimetry measured in the range of 40 to 200 ° C. is 0 to 1
The organic photoconductor is 0 J / g, and the water absorption of the binder resin used for the intermediate layer is 5.0% or less.

3. The inorganic particles are hydrophobic silica,
3. The organophotoreceptor as described in 1 or 2 above, wherein the hydrophobic silica has a hydrophobicity of 50% or more.

4. 4. The organic photoreceptor according to any one of 1 to 3, wherein the binder resin used in the surface layer has a water absorption rate of 0.5% or less.

5. The charge generation layer is used as a charge generation material and has a Bragg angle 2θ of an X-ray diffraction spectrum of Cu-Kα X-rays.
(5) The organophotoreceptor as described in (3) or (4) above, which contains a titanyl phthalocyanine pigment having a main peak at (± 0.2 °) and 27.2 °.

6. Using the organic photoconductor according to any one of 1 to 5 above, at least a charging step, an image exposure step,
An image forming method comprising forming an electrophotographic image through each step of a developing step and a cleaning step.

7. An image forming apparatus, wherein an electrophotographic image is formed by using the image forming method described in 6 above.

8. The organic photoconductor according to any one of 1 to 5 is integrally combined with any one of a charger, an image exposure device, a developing device, and a cleaning device, and is freely designed to be taken in and out of an image forming apparatus. Process cartridge characterized in that

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The organic photoreceptor of the present invention is an organic photoreceptor having at least a photosensitive layer provided on a conductive support, and the surface layer of the organic photoreceptor has a number average primary particle diameter of 1 nm or more and 1
40 to 20 containing inorganic particles of less than 00 nm, and the organic photoreceptor is conditioned under a relative humidity environment of 20 ° C. and 80%.
The endothermic energy change amount ΔH of the differential scanning calorimetry measured in the range of 0 ° C. is 0 to 10 J / g.

The organic photoreceptor of the present invention is an organic photoreceptor having an intermediate layer, a charge generation layer, a charge transport layer and a surface layer on a conductive support, wherein the surface layer has a number average primary particle diameter of 1 nm or more. 40 to 200, containing inorganic particles of less than 100 nm and conditioned under a relative humidity environment of 20 ° C. and 80%.
The amount of change in endothermic energy ΔH in differential scanning calorimetry measured in the range of 0 ° C. is 0 to 10 J / g, and the water absorption of the binder resin used in the intermediate layer is 5.0% or less. .

The organic photoreceptor of the present invention having the above-mentioned constitution improves the transferability of the toner formed on the organic photoreceptor and the cleaning performance of the residual toner on the photoreceptor,
Further, it is possible to prevent the occurrence of environmental memory and improve wear resistance.

The number average primary particle diameter of the inorganic particles contained in the surface layer of the present invention is 1 nm or more and less than 100 nm, preferably 10 nm or more and 90 nm or less, and most preferably 10 nm or more and less than 50 nm. When the number average primary particle size of the inorganic particles contained in the surface layer is less than 1 nm, fine irregularities are not formed on the surface of the photoconductor, and the effect of improving the transferability and cleaning property of the above toner is small, and 100 nm
In the above inorganic particles, the amount of change in endothermic energy ΔH in the differential scanning calorimetry measured in the range of 40 to 200 ° C. is 10
It tends to be larger than J / g. This increases the amount of substances that cause carrier traps such as water molecules, and as a result, tends to cause environmental memory. Further, the abrasion of the blade is increased, and defective cleaning is likely to occur. The amount of change in endothermic energy ΔH of the present invention is 0 to 10 J / g, and more preferably 0 to 8.0 J / g.

1 nm or more and 100 n used in the present invention
As the inorganic particles of less than m, fine particles of silica, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony or tantalum-doped tin oxide, zirconium oxide and the like are used. It can be preferably used. Among these, silica is preferable, and hydrophobic silica having a hydrophobic surface is particularly preferable in terms of cost, adjustment of particle size, easiness of surface treatment, and the like.

The number average primary particle diameter of the inorganic particles of the present invention is magnified 10,000 times by observation with a transmission electron microscope, 300 particles are randomly observed as primary particles, and the number average diameter of Feret's diameter is determined by image analysis. The measured value is calculated as.

The hydrophobicity of the above-mentioned hydrophobic silica is preferably 50% or more in terms of the degree of hydrophobicity represented by a measure of wettability with methanol (methanol wettability). If the degree of hydrophobicity is less than 50%, the amount of change in endothermic energy ΔH tends to be larger than 10 J / g, and as a result, environmental memory is likely to occur. The more preferable degree of hydrophobicity is 65% or more, and the most preferable degree of hydrophobicity is 70% or more.

Methanol wettability, which represents the degree of hydrophobicity, is an evaluation of the wettability of silica fine powder with respect to methanol. The wettability is measured by the following method.
50mL distilled water in a beaker with an internal capacity of 250mL
Then, 0.2 g of silica fine powder to be measured is added and stirred. Next, methanol is slowly added dropwise from a buret whose tip is immersed in a liquid until the silica fine powder is wholly wet. The amount of methanol required to completely wet the silica fine powder was a (mL).
Then, the hydrophobicity is calculated by the following formula (1).

Formula (1) Hydrophobicity = a / (a + 50) × 100 The above-mentioned hydrophobic silica can be obtained by hydrophobizing silica powder produced by a known wet method or dry method. In particular, a so-called fumed silica produced by a dry method (vapor-phase oxidation of a silicidized halogen compound) treated with a hydrophobizing agent is preferable because it has few water adsorption sites. This is manufactured by a conventionally known technique. For example, the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxyhydrogen flame is utilized, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl Further, in this manufacturing process, for example, by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound, silica and another metal oxide are mixed. It is also possible to obtain fine powder.

The hydrophobizing treatment of the silica powder is carried out by spraying a solution of the hydrophobizing agent dissolved in alcohol or the like on a dispersion of fine silica powder in a cloud shape by stirring or contacting the vaporized hydrophobizing agent. It can be carried out by a conventionally known method such as a dry treatment for adhering the silica powder, or a wet treatment for dispersing a silica powder in a solution and dropping a hydrophobizing agent into the solution for adhesion.

As the hydrophobizing agent, known compounds can be used, and specific examples are given below. Further, these compounds may be used in combination.

Examples of titanium coupling agents include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzene sulfonyl titanate and bis (dioctyl pyrophosphate) oxyacetate titanate.

As the silane coupling agent, γ- (2-
Aminoethyl) aminopropyltrimethoxysilane, γ
-(2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-vinylbenzylaminoethyl-N-γ-
Aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltri Examples thereof include methoxysilane, o-methylphenyltrimethoxysilane and p-methylphenyltrimethoxysilane.

Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil and amino-modified silicone oil.

These hydrophobizing agents are preferably added in an amount of 1 to 40% by mass with respect to the silica powder for coating.
3-30 mass% is more preferable.

A hydrogen polysiloxane compound may be used as the surface hydrophobizing agent. The molecular weight of the hydrogen polysiloxane compound is 1000 to 200.
Those of No. 00 are generally easily available, and have a good black spot prevention function. In particular, when methylhydrogenpolysiloxane is used for the final surface treatment, good effects can be obtained.

In the present invention, the above hydrophobicized hydrophobic silica is contained in the surface layer of the organic photoreceptor together with the binder. The ratio of the hydrophobic silica in the surface layer is 1 to 20% by mass, preferably 2% by mass of the binder. ˜15% by weight, most preferably 2 to 10% by weight. When it exceeds 20% by mass, the amount of change in endothermic energy ΔH of the photoconductor is set to 1
It becomes difficult to reduce the amount to 0 J / g or less, the transferability of the environmental memory and toner is deteriorated, and cleaning failure easily occurs. On the other hand, if it is less than 1% by mass, the abrasion resistance of the photoconductor tends to be lowered.

Amount of change in endothermic energy Δ of the photoconductor of the present invention
To reduce H to 10 J / g or less, the hydrophobic silica contained in the photoreceptor surface layer has a number average primary particle size of 1 nm or more and 10
It is necessary to use particles of less than 0 nm and reduce the water absorption of the binder resin used in each layer constituting the photoconductor. In particular, it is necessary to select a binder resin that reduces the water absorption of the surface layer and the intermediate layer. That is, under high temperature and high humidity, water molecules travel along the surface and the conductive support and easily enter the photosensitive layer, and in order to prevent this, it is important to reduce the water absorption of the surface layer and the intermediate layer.
It is also important to reduce the water absorption of the binder resin in the charge transport layer, which has the largest occupied volume in the photosensitive layer.

In the present invention, the inorganic fine particles in the surface layer are made hydrophobic, and at the same time, the water absorption rate of the binder resin in these surface layers is made small, so that the amount of change in endothermic energy Δ of the photoconductor is obtained.
It becomes possible to set H to 10 J / g or less.

That is, it is preferable that the binder resin used in the surface layer is selected from binder resins having a water absorption of 0.5% or less, preferably 0.3% or less and having substantially no hygroscopicity. As such a binder resin, resins such as polycarbonate, polyester and polyarylate are preferable, and polycarbonate having particularly good electrophotographic characteristics is preferable.

The water absorption rate of the binder resin in the surface layer means the mass average of the water absorption rates of all the binder resins capable of forming a film contained in the surface layer. The water absorption rate when it is contained above is
The weight average water absorption of each binder resin is 1.0% or less,
It is preferable to select the resin so that it is preferably 0.5% or less. For example, 5 g of resin A having a water absorption rate of 1.5% and 1 g of resin B having a water absorption rate of 0.5% are used as the binder resin of the surface layer.
When the mixed resin of 0 g was used, the water absorption of the binder resin in the surface layer was (1.5 × 5 + 0.5 × 10) /
(5 + 10) = 0.83% water absorption.

The definition of the water absorption of the binder resin for the intermediate layer is the same as that for the binder resin for the surface layer.

Measurement Condition of Water Absorption Rate The mass of a measurement sample which has been sufficiently dried in advance is precisely weighed. Next, the sample is put into ion-exchanged water maintained at 20 ° C., and after a certain period of time, the sample is pulled up and the water on the sample surface is wiped with a clean cloth to measure the mass. The above operation was repeated until the mass increase became saturated, and the value obtained by dividing the increased mass (increase) of the resulting sample by the initial mass was taken as the water absorption rate.

On the other hand, the binder resin for the intermediate layer is required to have properties such as adhesiveness with the conductive support, adhesiveness with the charge generating layer, and blocking properties of free carriers from the conductive support. , Volume resistance is 10
A resin having a polar group of ⁹ to 10 ¹³ Ωcm is preferable. A polyamide resin is preferably used as the resin having such resistance characteristics and improved dissolution solvent property. The water absorption rate is preferably 5% or less, preferably 3.0% or less. When the water absorption rate of the binder of the intermediate layer is more than 5%, the hygroscopicity in the photosensitive layer through the intermediate layer is increased, and the environmental memory and the like are increased. As a polyamide resin satisfying such characteristics, resins having the following chemical structures are listed.

[0045]

[Chemical 1]

[0046]

[Chemical 2]

Next, the layer structure of the organic photoreceptor of the present invention will be described. In the present invention, the organic photoconductor means an electrophotographic photoconductor constituted by giving an organic compound at least one of a charge generation function and a charge transport function, which are indispensable for the construction of the electrophotographic photoconductor, All known organic electrophotographic photoconductors such as a photoconductor composed of the organic charge generating substance or the organic charge transporting substance, a photoconductor having a charge generating function and a charge transporting function formed of a polymer complex are included.

The layer structure of the above-mentioned organic photoreceptor is not particularly limited, but basically, the charge generation layer, the charge transport layer, or the charge generation / charge transport layer (having the functions of charge generation and charge transport in the same layer). Although it is composed of a photosensitive layer such as a layer), a surface layer may be coated thereon. Further, the surface layer preferably has the function of a protective layer and the function of transporting charges.

The specific constitution of the photoconductor used in the present invention will be described below. Conductive Support As the conductive support used in the photoreceptor of the present invention, a sheet-shaped or cylindrical conductive support is used.

The cylindrical conductive support of the present invention means a cylindrical support required to form an image endlessly by rotating, and has a straightness of 0.1 mm or less and a shake of 0.1 mm or less. A conductive support in the range of is preferable. If the straightness and the shake range are exceeded, good image formation becomes difficult.

As the material of the conductive support, a metal drum of aluminum, nickel or the like, a plastic drum on which aluminum, tin oxide, indium oxide or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. it can. It is preferable that the conductive support has a specific resistance of 10 ³ Ωcm or less at room temperature.

The conductive support used in the present invention may have a surface on which a pore-treated alumite film is formed. The alumite treatment is usually carried out in an acidic bath of chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, it is preferable that the sulfuric acid concentration is 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is around 20 ° C., and the applied voltage is about 20 V. It is not limited. The average thickness of the anodized film is usually 2
It is preferably 0 μm or less, and particularly preferably 10 μm or less.

Intermediate Layer In the present invention, the above-mentioned intermediate layer having a barrier function is provided between the conductive support and the photosensitive layer.

In the intermediate layer of the present invention, it is preferable that titanium oxide is contained in the binder resin having a small water absorption rate. The number average primary particle diameter of the titanium oxide particles is preferably 10 nm or more and 400 nm or less,
m-200 nm is preferable. If it is less than 10 nm, the effect of preventing moire due to the intermediate layer is small. On the other hand, 400 nm
When it is larger than the above range, the titanium oxide particles in the coating solution for the intermediate layer are liable to settle, and as a result, the uniform dispersibility of the titanium oxide particles in the intermediate layer is poor and black spots are also likely to increase. The intermediate layer coating solution using titanium oxide particles having a number average primary particle size in the above range has good dispersion stability, and the intermediate layer formed from such a coating solution has a black spot prevention function and environmental characteristics. Has good crack resistance.

The shape of the titanium oxide particles used in the present invention may be dendritic, acicular or granular. Titanium oxide particles having such a shape are, for example, in the case of titanium oxide particles, the crystalline form is anatase. Type, rutile type, amorphous type and the like, any crystal type may be used, and two or more crystal types may be mixed and used. Among them, the rutile type and granular type are the best.

The titanium oxide particles of the present invention are preferably subjected to a surface treatment. One of the surface treatments is that the surface treatment is carried out a plurality of times, and the last surface treatment among the plurality of surface treatments is carried out. The surface treatment is carried out using a reactive organosilicon compound. Further, among the plurality of surface treatments, at least one surface treatment is at least one surface treatment selected from alumina, silica, and zirconia, and finally a surface treatment using a reactive organosilicon compound. Is preferably performed.

Alumina treatment, silica treatment, and zirconia treatment are treatments for depositing alumina, silica, or zirconia on the surface of titanium oxide particles. Alumina, silica, and zirconia are deposited on these surfaces. Also included are hydrates of zirconia. Further, the surface treatment of the reactive organic silicon compound means that the reactive organic silicon compound is used in the treatment liquid.

Thus, the surface treatment of titanium oxide particles such as titanium oxide particles is performed at least twice or more, whereby the surface of titanium oxide particles is uniformly coated (treated), and the surface treated titanium oxide particles are treated. When is used for the intermediate layer, it is possible to obtain a good photoconductor in which the dispersibility of titanium oxide particles such as titanium oxide particles in the intermediate layer is good and image defects such as black spots do not occur.

Examples of the above-mentioned reactive organosilicon compound include compounds represented by the following general formula (1). If the compound can undergo a condensation reaction with a reactive group such as a hydroxyl group on the surface of titanium oxide, the following compound can be used. Not limited.

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

The organosilicon compound represented by the general formula (1) may be used alone or in combination of two or more kinds.

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

As a preferred reactive organosilicon compound used for the surface treatment, a polysiloxane compound can be mentioned. The molecular weight of the polysiloxane compound is 1000 to 20.
Those of 000 are generally easily available, and have a good black spot preventing function.

Particularly, when methylhydrogenpolysiloxane is used for the final surface treatment, good effects can be obtained.

Photosensitive Layer The photosensitive layer structure of the photoconductor of the present invention may be a single-layer photosensitive layer structure in which one layer has a charge generating function and a charge transporting function on the intermediate layer, but it is more preferable that the photosensitive layer is photosensitive. It is preferable that the function of the layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, the charge generation layer (C
GL) and a charge transport layer (CTL) thereon. In the case of the photoconductor for positive charging, the order of the layers is the reverse of that of the photoconductor for negative charging. The most preferable photosensitive layer structure of the present invention is a negatively charged photosensitive member structure having the above-mentioned function separation structure.

The constitution of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below. Charge Generation Layer The charge generation layer contains a charge generation material (CGM). If necessary, a binder resin and other additives may be contained as other substances.

In the organic photoreceptor of the present invention, as the charge generating substance, for example, other phthalocyanine pigment, azo pigment, perylene pigment, azurenium pigment or the like can be used alone or in combination.

When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is formal resin, butyral resin, silicone resin, silicone modified butyral resin, phenoxy resin. Resin etc. are mentioned. The ratio of the binder resin to the charge generating substance is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.1 μm to 2 μm.

Charge Transport Layer The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing CTM to form a film. Other substances may optionally contain additives such as antioxidants.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Of these, CTM that can minimize the increase in residual potential due to repeated use has high mobility and has a characteristic that the difference in ionization potential with the combined CGM is 0.5 (eV) or less, and preferably 0. It is not more than 30 (eV).

The ionization potentials of CGM and CTM are measured by a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

The binder resin used in the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, 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 resins and copolymer resins containing two or more of the repeating unit structures of these resins. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinylcarbazole may be mentioned. Of these, a polycarbonate resin having a low water absorption rate, good CTM dispersibility, and good electrophotographic characteristics is most preferable.

The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. Also, the thickness of the charge transport layer is 10 to 40 μm.
m is preferred.

Surface Layer As the surface layer of the present invention, the surface layer containing the above-mentioned inorganic particles is used. Further, it is preferable that the surface layer contains a charge-transporting substance to impart a charge-transporting property. That is, it is most preferable that the charge transport layer has a plurality of layers and the uppermost layer thereof is the surface layer of the present invention.

Although the most preferable layer constitution of the photoconductor of the present invention has been described above, a photoconductor layer constitution other than the above may be used in the present invention.

The solvent or dispersion medium used for forming the photosensitive layer, the protective layer and the like includes n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-.
Dimethylformamide, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-
Examples thereof include trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve and the like. The present invention includes, but is not limited to, dichloromethane, 1,2
-Dichloroethane, methyl ethyl ketone and the like are preferably used. Further, these solvents can be used alone or as a mixed solvent of two or more kinds.

Next, as a coating processing method for producing an organic photoreceptor, a coating processing method such as dip coating, spray coating, or circular amount regulation type coating is used. The coating processing on the upper layer side of the photosensitive layer is a lower layer. It is preferable to use a coating processing method such as spray coating or circular amount control type (a circular slide hopper type is a typical example) coating in order to prevent the film from being dissolved as much as possible and to achieve uniform coating processing. It is most preferable to use the circular amount regulation type coating processing method for the protective layer. The circular amount control type coating is described in, for example, JP-A-58-1890.
This is described in detail in Japanese Patent No. 61.

Next, an image forming apparatus using the organic photoconductor of the present invention will be described. FIG. 1 is a sectional configuration diagram of an image forming apparatus as an example of the image forming method of the present invention.

In FIG. 1, reference numeral 50 is a photosensitive drum (photosensitive member) which is an image bearing member, and an organic photosensitive layer is applied onto the drum.
A photosensitive member having the resin layer of the present invention applied thereon is grounded and driven and rotated clockwise. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the peripheral surface of the photosensitive drum 50 by corona discharge. This charger 5
Prior to the charging by 2, the exposure may be performed by the pre-charge pre-exposure unit 51 using a light emitting diode or the like to eliminate the history of the photo conductor in the pre-image formation to eliminate the charge on the peripheral surface of the photo conductor.

After uniform charging of the photosensitive member, image exposure based on the image signal is performed by the image exposure device 53 as the image exposure means. 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 whose optical path is bent by the reflection mirror 532 through the f.theta. Lens, etc., scans the photosensitive drum to form an electrostatic latent image.

The reversal development process of the present invention means that the surface of the photoconductor is uniformly charged by the charger 52 to develop the image-exposed region, that is, the exposed portion potential (exposed portion region) of the photosensitive member. It is an image forming method that visualizes by a step (means). 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 by the developing device 54 as a developing means. A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and holds the developer and rotates.
Inside the developing unit 54, the developer stirring and conveying members 544, 543,
The developer is constituted by a conveyance amount regulating member 542 and the like, and the developer is agitated and conveyed to be supplied to the developing sleeve, and the supply amount thereof is controlled by the conveyance amount regulating member 542. The amount of the developer conveyed varies depending on the linear velocity of the organic photoconductor applied and the specific gravity of the developer, but is generally 20 to 200 mg.
The range is / cm ² .

The developer is, for example, a carrier in which an insulating resin is coated around the above-mentioned ferrite as a core, a coloring agent such as carbon black, a charge control agent, and a low-molecular-weight polyolefin whose main material is the above-mentioned styrene-acrylic resin. The toner is formed by externally adding silica, titanium oxide, or the like to the colored particles made of, and the developer is transported to the developing area with the layer thickness regulated by the transport amount regulating member, and development is performed. At this time, normally, a DC bias is applied between the photosensitive drum 50 and the developing sleeve 541, and if necessary, an AC bias voltage is applied to develop. Further, the developer is developed in a state of being in contact with or non-contacting with the photoreceptor. The potential of the photoconductor is measured by providing a potential sensor 547 above the developing position as shown in FIG.

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

In the transfer area, the transfer electrode (transfer means: transfer device) 58 operates on the peripheral surface of the photosensitive drum 50 in synchronization with the transfer timing, and the recording paper P fed is charged with the opposite polarity to the toner. To transfer the toner.

Next, the recording paper P is separated by a separating electrode (separator) 59.
Is discharged by the peripheral surface of the photoconductor drum 50 and conveyed to the fixing device 60. The heat roller 601 and the pressure roller 602 heat and pressurize the toner to fuse the toner, and then the paper is discharged from the outside of the device via the paper discharge roller 61. Is discharged to. The transfer electrode 58 and the separation electrode 59 stop the primary operation after passing the recording paper P and prepare for the next toner image formation. In FIG. 1, a transfer band electrode of a corotron is used as the transfer electrode 58. The setting condition of the transfer electrode varies depending on the process speed (peripheral speed) of the photoconductor and cannot be specified unconditionally. For example, the transfer current is +
100 to +400 μA, transfer voltage +500 to +
2000V can be used as the set value.

On the other hand, the photosensitive drum 50 after separating the recording paper P removes and cleans the residual toner by pressing the blade 621 of the cleaning device (cleaning means) 62.
The pre-charging pre-exposure unit 51 again removes electricity and the charger 52 charges, and the next image forming process starts.

Reference numeral 70 denotes a detachable process cartridge in which a photoconductor, a charging device, a transfer device, a separator and a cleaning device are integrated.

The organic photoreceptor of the present invention is generally applied to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers and liquid crystal shutter type printers. It can be widely applied to devices such as plate making and facsimile.

[0090]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto. In addition, "part" in a sentence represents a "mass part."

Example Preparation of photoconductor 1 Photoreceptor 1 was prepared as described below.

The surface of a cylindrical aluminum support having a diameter of 100 mmφ and a length of 346 mm was cut to obtain a surface roughness R.
A conductive support having z = 1.5 (μm) was prepared.

<Intermediate layer> The following intermediate layer dispersion liquid was diluted 2-fold with the same mixed solvent and allowed to stand overnight, followed by filtration (filter;
Rigimesh 5 μm filter manufactured by Nippon Pall Co., Ltd.) was applied to prepare an intermediate layer coating solution.

Polyamide Resin (Exemplified Polyamide N-1) 1 Part Titanium oxide SMT500SAS (manufactured by Teika Co., Ltd .: titanium oxide particles having a number average primary particle diameter of 35 nm are subjected to a primary treatment of silica / alumina and a secondary treatment of methylhydrogenpolysiloxane What was carried out) 3 parts Methanol 10 parts Dispersion was carried out for 10 hours by a batch method using a sand mill as a disperser.

The above-mentioned coating solution for the intermediate layer was applied onto the above support so as to give a dry film thickness of 2 μm.

<Charge Generation Layer> Y-type titanyl phthalocyanine (titanyl phthalocyanine having a maximum peak at 27.2 degrees of Bragg angle 2θ (± 0.2) of Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts Polyvinyl butyral Resin (# 6000-C: manufactured by Denki Kagaku Kogyo Co., Ltd.) 10 parts t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts are mixed and dispersed for 10 hours using a sand mill to form a charge generation layer. A coating liquid was prepared. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.3 μm.

<Charge Transport Layer> Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl) triphenylamine) 225 parts Polycarbonate (Polycarbonate Z having the following structure: molecular weight 30,000, water absorption 0 23%) 300 parts Antioxidant (Irganox 1010: manufactured by Ciba Geigy) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part is mixed and dissolved to prepare a charge transport layer coating liquid. did. This coating solution is applied onto the charge generation layer by a dip coating method to obtain a dry film thickness of 2
A 0 μm charge transport layer was formed.

<Surface Layer> Charge Transport Material (4,4′-Dimethyl-4 ″-(α-phenylstyryl) triphenylamine) 225 Parts Polycarbonate (Polycarbonate A having the following structure: molecular weight 30,000, water absorption: 0. 25%) 300 parts Hydrophobic silica (Table 1) Antioxidant (LS2626: manufactured by Sankyo) 6 parts 1,3-Dioxolane 2000 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) Circulation dispersion was performed by a circulation dispersion device capable of irradiating sound waves to prepare a surface layer coating solution. A dry film thickness of 5 is obtained by applying this coating solution onto the charge transport layer by a circular amount regulation type coating method.
It was applied so as to have a thickness of μm, and dried at 110 ° C. for 70 minutes to prepare a photoconductor 1.

[0099]

[Chemical 3]

Preparation of Photoreceptors 2 to 20 Photoreceptors 2 to 20 were prepared in the same manner as the photoreceptor 1 except that the hydrophobic silica of the surface layer and the binder of the intermediate layer were changed as shown in Table 1. did.

[0101]

[Table 1]

In Table 1, N-9 is methoxymethylated nylon 6 (the number of carbons between acid bonds is 5, the degree of methoxymethylation is 25%). Measurement of change in endothermic energy ΔH Differential scanning calorimetry (DSC) of a photoconductor is a method of adding energy necessary for canceling a temperature difference between a thermally stable standard substance and a sample heated at a constant rate. Since the peak area of DSC is proportional to the endothermic amount, it can be quantified according to the following equation.

MΔH = KA Here, M is the mass of the sample, ΔH is the amount of energy change per unit mass of the sample, K is the device constant, and A is the peak area.

For the measurement, the photoconductor prepared in the example was allowed to stand for 24 hours in an environment having a relative humidity of 80% to adjust the humidity. Then, the sample was stored in a sealed container until the DSC measurement, and the measurement was performed under the following conditions within 60 minutes after the completion of the humidity control.

Apparatus: Differential scanning calorimeter DSC-20 Thermal controller SSC-580 (manufactured by Seiko Denshi Kogyo Co., Ltd.) Measurement conditions: Measurement temperature 35 to 300 ° C. Temperature increase temperature 10 ° C./min Measurement environment Air Still atmosphere 2. Konica7 digital copying machine made by Konica Corporation as an image evaluation and evaluation machine
075 (having corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, blade cleaning, cleaning auxiliary brush roller adoption process) was used, and photoconductors 1 to 20 were mounted on the copying machine and evaluated. The cleaning property and the image evaluation were carried out by copying an original image in which a character image having a pixel ratio of 7%, a human face photograph, a solid white image, and a solid black image are each divided into quarters on A4 neutral paper. High temperature and high humidity environment (HH: 30)
Continuous 100,000 copies were made at 80 ° C and 80% RH, and the following evaluations were performed.

Evaluation reference image blur (total inspection of 100,000 copies: visual judgment) ⊚: Image blur is 30 or less: Good ○: Image blur is 31 to 100: Practically no problem △: 101-500 sheets of image blurring: Re-evaluation of practicability is required ×: 501 or more sheets of image blurring: Level that poses a practical problem Environmental memory: Konica 7075 copy machine under HH After standing for 24 hours, low humidity and low temperature (LL: 20% RH, 1
(0 ° C.) and after 30 minutes, copied. A halftone image with a density of 0.3 in the original image is copied to a density of 0.3 and judged by the density difference (ΔHD = maximum density-minimum density) of the copied image ◎: ΔHD is less than 0.02: good ○: ΔHD Is 0.02 or more and less than 0.04: practically no problem level Δ: ΔHD is 0.04 or more and less than 0.06: re-evaluation of practicability is required ×: ΔHD is 0.06 or more: practically problematic Level cleaning property (100,000 copies are all inspected) ◎: Image defects due to toner slippage are 30 or less: Good ○: Image defects due to toner slippage are 31 to 31
100 sheets: No problem in practical use Δ: Image defects due to toner slippage are 101 to 500 sheets: Re-evaluation of practicability is required ×: Image defects due to toner slippage are 501 sheets or more: Practical use Level 3, which is a problem. Depletion amount of photoconductor film thickness The depletion amount of the photoconductor film was determined by calculating the difference between the average film thickness of the photoconductor film measured at the start of actual copying evaluation and at the end of copying 100,000 sheets.

Film Thickness Measuring Method The film thickness of the photosensitive layer is measured at random at 10 uniform film thickness portions, and the average value is taken as the film thickness of the photosensitive layer. The film thickness measuring device is an eddy current type film thickness measuring device EDDY560C (HELMUT
FISCHER GMBTE CO.), And the difference in the thickness of the photosensitive layer before and after the actual copying test is taken as the amount of film thickness loss.

Other Evaluation Conditions The other evaluation conditions using the above 7075 were set to the following conditions.

Charging conditions Charging device: Scorotron charger, initial charging potential of -750
V exposure condition Set the exposure amount to make the exposed portion potential -50V.

Development conditions DC bias: -550V The developer is composed of a carrier having ferrite as a core and coated with an insulating resin, a styrene acrylic resin as a main material, a colorant such as carbon black, a charge control agent, and a low molecular weight polyolefin. A toner developer was used in which silica and titanium oxide were externally added to colored particles having a volume average particle diameter of 7.3 μm produced by a polymerization method.

Transfer condition Transfer pole: Corona charging method Cleaning condition Hardness 70 °, impact resilience 65%, thickness 2 in cleaning part
(Mm) and a cleaning blade having a free length of 9 mm were brought into contact with each other by a weight load method in the counter direction so as to have a linear pressure of 18 (N / m).

The evaluation results are shown in Table 2.

[0113]

[Table 2]

As is clear from Table 2 above, the surface layer contains hydrophobic silica having a number average primary particle size of 1 nm or more and less than 100 nm, and the endothermic energy change amount ΔH is 0 to 0.
Photosensitive members 1 to 9, 14, and 1 in the present invention within 10 J / g
Nos. 6, 17 and 19 show good characteristics in each image evaluation of image blur, environmental memory, cleaning property and film thickness wear amount, whereas the endothermic energy change amount ΔH is 10 J /
Image blur, environmental memory, and cleaning property deterioration are caused in the photoconductors 10, 11, and 15 larger than g, and cleaning property and image blurring are remarkable in the photoconductors 12 and 13 whose number average primary particle size is larger than 100 nm. Is. Further, the image blur and the evaluation of the environmental memory of the photoconductor 18 in which the water absorption of the binder of the intermediate layer is larger than 5% are deteriorated. On the other hand, the image blur of the photoconductor 20 having the surface layer containing no hydrophobic silica is reduced and the amount of film thickness loss is also increased.

[0115]

As is apparent from the examples, by using the constitution of the present invention, it is possible to provide a highly durable electrophotographic photosensitive member with improved image blur, environmental memory and cleaning property. Further, it is possible to provide an image forming method, an image forming apparatus and a process cartridge which can achieve a good electrophotographic image using the electrophotographic photosensitive member.

[Brief description of drawings]

FIG. 1 is a sectional view of an image forming apparatus as an example of an image forming method of the present invention.

[Explanation of symbols]

50 photoconductor drum (or photoconductor) 51 Pre-charge exposure unit 52 Charger 53 Image exposure device 54 Developer 541 Development sleeve 543,544 developer stirring and conveying member 547 potential sensor 57 Paper Feed Roller 58 transfer electrode 59 Separation electrode (separator) 60 fixing device 61 Paper ejection roller 62 cleaning device 70 Process cartridge

Claims (8)

[Claims] 1. An organic photoreceptor having at least a photosensitive layer provided on a conductive support, wherein the surface layer of the organic photoreceptor contains inorganic particles having a number average primary particle diameter of 1 nm or more and less than 100 nm, and 20 An organophotoreceptor characterized in that the amount of change in endothermic energy ΔH in differential scanning calorimetry measured in the range of 40 to 200 ° C. is 0 to 10 J / g, the humidity being controlled in a relative humidity environment of 80 ° C. and 80%. 2. An intermediate layer, a charge generation layer, and a conductive support,
In an organic photoreceptor having a charge transport layer and a surface layer, the surface layer contains inorganic particles having a number average primary particle diameter of 1 nm or more and less than 100 nm, and is conditioned under a relative humidity environment of 20 ° C. and 80%, 40 The endothermic energy change amount ΔH of the differential scanning calorimetry measured in the range of ˜200 ° C. is 0 to 10 J /
The water absorption of the binder resin used for the intermediate layer is 5.0% or less, and the organophotoreceptor is characterized by being g. 3. The organophotoreceptor according to claim 1, wherein the inorganic particles are hydrophobic silica, and the hydrophobicity of the hydrophobic silica is 50% or more. 4. The organophotoreceptor according to claim 1, wherein the binder resin used in the surface layer has a water absorption rate of 0.5% or less. 5. The charge generation layer comprises C as a charge generation material.
Bragg angle 2θ of X-ray diffraction spectrum of u-Kα X-ray
The organophotoreceptor according to claim 3 or 4, further comprising a titanyl phthalocyanine pigment having a main peak at 27.2 ° (± 0.2 °). 6. Using the organic photoconductor according to claim 1, at least a charging step, an image exposure step,
An image forming method comprising forming an electrophotographic image through each step of a developing step and a cleaning step. 7. An image forming apparatus, wherein an electrophotographic image is formed using the image forming method according to claim 6. 8. The organic photoconductor according to claim 1 and any one of a charging device, an image exposing device, a developing device, and a cleaning device are integrally combined to form an image. A process cartridge that is designed to be freely inserted into and removed from the device.