JP7283131B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses (hereinafter often referred to as "image forming apparatuses") are required to have a long service life and stable image quality. The life of the photoreceptor constituting the image forming apparatus is roughly determined by the degree of wear of the photoreceptor layer. Therefore, in recent years, in order to reduce wear and tear of the photoreceptor, a protective layer made of a curable resin has been provided as the outermost layer of the photoreceptor.

However, when a photoreceptor having a protective layer made of a curable resin is charged by the proximity charging method, the speed of deterioration of the surface of the photoreceptor becomes faster than the speed of surface polishing, and discharge occurs. The product tends to adhere to the surface of the photoreceptor. The adhered discharge products increase the torque, and cleaning defects and toner filming tend to occur due to curling or chipping of the cleaning blade.

As a means for solving such problems, for example, Patent Document 1 describes applying a filler surface-treated with a silicone treatment agent to the outermost layer of a photoreceptor in order to impart lubricity to the photoreceptor. ing. Moreover, Patent Document 2 describes the use of a fatty acid metal salt, which is less likely to be deteriorated by charging, as a lubricant.

Further, in an image forming apparatus, a negatively charged toner and a photoreceptor whose surface is charged by a charging means and has the same negatively charged polarity as the toner are normally used. Visualization (development) is performed by attaching charged toner to a portion where the absolute value of the potential is lowered by image exposure from the surface potential of the surface of the photosensitive member charged by the charging means. Here, in some cases, a lubricant is applied to the surface of the photoreceptor before the photoreceptor and the toner come into contact with each other in order to improve the cleanability of the photoreceptor.

JP-A-5-265244 JP 2009-282078 A

According to research by the present inventors, when printing is performed while applying a fatty acid metal salt as a lubricant to a photoreceptor to which a filler (such as metal oxide particles) whose surface has been treated with a silicone treatment agent is applied, a problem called lubricant memory occurs. occurs remarkably. Lubricant memory is a phenomenon in which there is a large difference in image density between a non-strip area with a large amount of lubricant and a band area with a small amount of lubricant on the surface of a photoreceptor. The image density has increased.

By reducing the amount of lubricant applied to the surface of the photoreceptor, the difference in surface potential between the band and non-band portions was reduced, and the lubricant memory could be suppressed. However, a decrease in the amount of lubricant applied resulted in a decrease in cleanability.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that maintains cleanability over a long period of time and suppresses the occurrence of lubricant memory.

An image forming apparatus of the present invention for solving the above problems comprises a photoreceptor having a protective layer as an outermost layer, charging means for charging the surface of the photoreceptor, and exposing the photoreceptor charged by the charging means. exposure means, developing means for supplying toner to the photoreceptor exposed by the exposure means to form a toner image, transfer means for transferring the toner image formed on the photoreceptor, and the surface of the photoreceptor. and a lubricant applying means for applying a lubricant to the surface of the photoreceptor, wherein the outermost layer of the photoreceptor comprises a polymerizable monomer and at least one At least one of the metal oxide particles is surface-treated with a surface treatment agent, and the lubricant comprises a fatty acid metal salt and boron nitride include.

The present invention provides an image forming apparatus that maintains cleanability over a long period of time and suppresses the occurrence of lubricant memory.

1 is an explanatory sectional view showing an example of the configuration of an image forming apparatus according to the present invention; FIG. 1 is an explanatory cross-sectional view showing an example of the configuration of a main part of an image forming apparatus according to the present invention; FIG. FIG. 2 is an explanatory cross-sectional view showing an example of the configuration of charging means in the image forming apparatus of the present invention; 1 is a schematic configuration diagram showing an example of a production apparatus used for producing composite particles (core-shell particles). FIG.

The present invention will be specifically described below.

One embodiment of the present invention is an image forming apparatus. In the image forming apparatus of the present invention, the protective layer of the photoreceptor is the outermost layer, and the outermost layer is a resin composition containing a polymerizable monomer and at least one metal oxide particle surface-treated with a surface treatment agent. It consists of a polymerized and cured product. Furthermore, the lubricant applied to the surface of the photoreceptor contains a fatty acid metal salt and boron nitride. By combining a photoreceptor having such a specific outermost layer and a specific lubricant, the image forming apparatus of the present invention achieves both long-term cleanability and suppression of lubricant memory. Although the action mechanism (mechanism) by which the above effects are obtained is not clear, it is speculated as follows.

As a result of intensive studies by the present inventors on substances contained in the outermost layer of the photoreceptor and substances contained in the lubricant, it was found that the surface treatment agent (especially silicone treatment agent) for the surface of the metal oxide particles contained in the outermost layer of the photoreceptor is , the triboelectrification sequence was found to be on the negatively charged side, whereas the triboelectrification sequence of fatty acid metal salts contained in conventional lubricants was found to be on the positively charged side. On the surface of the photoreceptor during image formation, there are a non-band portion with a large amount of lubricant and a band portion with a small amount of lubricant. . However, when the toner and the photoreceptor are rubbed by the developing means, the rubbing electrification sequence of the surface treatment agent contained in the outermost layer of the photoreceptor is on the negative charge side in the belt portion where the lubricant is not present much. The surface potential of the strip increases. On the other hand, in the non-stripped area where a large amount of lubricant is present, the triboelectric charge sequence of the fatty acid metal salt contained in the lubricant is on the positive charge side, so the surface potential is significantly lowered. As a result, the surface potential difference between the strip and the non-stripe increases, causing lubricant memory in which the image density of the non-stripe is high.

At this time, in addition to the fatty acid metal salt, if the lubricant contains boron nitride, which has a negative charge order in the triboelectrification order and has a lubricating function, when the toner and the photoreceptor are rubbed, a large amount of the lubricant is present. A decrease in the surface potential of the band is suppressed. As a result, the surface potential difference between the band portion and the non-band portion is reduced, and the occurrence of lubricant memory is suppressed.

When the lubricant contains only boron nitride, the surface potential of the non-band portion where a large amount of the lubricant is present remarkably increases when the toner is rubbed against the photoreceptor. As a result, the surface potential difference between the band and the non-band becomes large, and the image density of the band where the surface potential is lower becomes higher (the image density of the non-band becomes lighter). Lubricant memory occurs. .
The present invention has been completed based on the above findings.

The image forming apparatus of the present invention comprises a photoreceptor having a protective layer as the outermost layer, charging means for charging the surface of the photoreceptor, exposure means for exposing the photoreceptor charged by the charging means, and the exposure means. developing means for supplying toner to the photoreceptor exposed to light to form a toner image; transfer means for transferring the toner image formed on the photoreceptor; and removing toner remaining on the surface of the photoreceptor. The image forming apparatus includes cleaning means and lubricant applying means for applying a lubricant to the surface of the photoreceptor.

FIG. 1 is an explanatory sectional view showing an example of the configuration of the image forming apparatus of the present invention.
This image forming apparatus 100 is called a tandem type color image forming apparatus, and has four sets of image forming units 110Y, 110M, 110C, and 110Bk, paper feeding/conveying means 150, and fixing means 170. FIG. A document image reading device SC is arranged on the upper part of the main body of the image forming apparatus 100 .

The image forming units 110Y, 110M, 110C, and 110Bk are arranged side by side in the vertical direction. The image forming units 110Y, 110M, 110C, and 110Bk include rotating drum-shaped photoreceptors 111Y, 111M, 111C, and 111Bk, and lubricant supply means sequentially arranged along the rotation direction of the photoreceptors in the outer peripheral surface area. 116Y, 116M, 116C, 116Bk; charging means 113Y, 113M, 113C, 113Bk; exposure means 115Y, 115M, 115C, 115Bk; developing means 117Y, 117M, 117C, 117Bk; 133Y, 133M, 133C and 133Bk, cleaning means 119Y, 119M, 119C and 119Bk, and lubricant removing means 114Y, 114M, 114C and 114Bk. Toner images of yellow (Y), magenta (M), cyan (C), and black (Bk) are formed on the photoreceptors 111Y, 111M, 111C, and 111Bk, respectively. Since the image forming units 110Y, 110M, 110C, and 110Bk are configured in the same manner except that the colors of the toner images formed on the photoreceptors 111Y, 111M, 111C, and 111Bk are different, an example of the image forming unit 110Y will be described below. .

[Photoreceptor]
The photoreceptor 111Y is a drum-shaped one having a protective layer made of a polymerized and cured resin composition as the outermost layer. Specifically, the photoreceptor 111Y of this example has an intermediate layer on a conductive support, and a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance are formed on the intermediate layer. It has a layer structure in which a photosensitive layer is formed by laminating layers in this order, and a protective layer is formed as the outermost layer on the photosensitive layer (charge transport layer). The photosensitive layer may have a single-layer structure containing a charge-generating substance and a charge-transporting substance. The electrophotographic photoreceptor having such a structure will be described in detail below.

(Conductive support)
The conductive support is a member that supports the photosensitive layer and has conductivity. Preferred examples of the conductive support include a metal drum or sheet, a plastic film with a laminated metal foil, a plastic film with a deposited conductive material film, a conductive material, or a conductive material and a binder. A metal member, a plastic film, a paper, etc. having a conductive layer formed by applying a paint made of a resin can be used. Preferred examples of the metal include aluminum, copper, chromium, nickel, zinc and stainless steel, and preferred examples of the conductive substance include the above metal, indium oxide and tin oxide.

(Photosensitive layer)
The photosensitive layer is a layer for forming an electrostatic latent image of a desired image on the surface of the photoreceptor by exposure means described later. The photosensitive layer may be a single layer, or may be composed of a plurality of laminated layers. Preferred examples of the photosensitive layer include a single layer containing a charge-transporting substance and a charge-generating substance, and a laminate of a charge-transporting layer containing a charge-transporting substance and a charge-generating layer containing a charge-generating substance. mentioned.

(protective layer)
The protective layer is a layer made of a polymerized cured product of a resin composition for improving the mechanical strength of the surface of the photoreceptor and improving the scratch resistance and abrasion resistance. In the image forming apparatus of the present invention, the protective layer is the outermost layer. A preferable example of the protective layer is a layer containing a cured product of a composition containing a polymerizable monomer.

(outermost layer)
In this specification, the outermost layer of the photoreceptor means the outermost layer on the side in contact with the toner, and the protective layer is the outermost layer. In one embodiment of the present invention, the outermost layer comprises a cured polymer of a resin composition containing a polymerizable monomer and at least one metal oxide particle, and at least one of the metal oxide particles is a surface treatment agent. surface treated with
The constituent components of the outermost layer are described in detail below.

<Metal oxide particles>
The outermost layer contains a cured resin composition containing metal oxide particles, and at least one of the metal oxide particles is surface-treated with a surface treatment agent. Metal oxide particles surface-treated with a surface treatment agent are considered to be coated particles containing chemical species (coating layer) derived from the surface treatment agent and metal oxide particles. The surface-treated metal oxide particles may have a chemical species (coating layer) derived from the surface treatment agent on at least part of the surface.

As used herein, the term "metal oxide particles" refers to particles at least the surface of which is composed of a metal oxide. Examples of metal oxides constituting metal oxide particles are not particularly limited, but are alumina, silica, magnesium oxide, zinc oxide, lead oxide, tin oxide, tantalum oxide, indium oxide, bismuth oxide, yttrium oxide, and cobalt oxide. , copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, tin oxide, titanium oxide, niobium oxide, molybdenum oxide, vanadium oxide, copper aluminum oxide, antimony ion-doped tin oxide, and the like. . These metal oxide particles can be used alone or in combination of two or more. Moreover, the metal oxide particles may be synthetic products or commercially available products.

Among these, alumina particles, tin oxide particles, and silica particles are preferred.

The number average primary particle size of the metal oxide particles is preferably 50 nm or more and 500 nm or less, more preferably 65 nm or more and 400 nm or less, and even more preferably 80 nm or more and 300 nm or less. When the number-average primary particle size of the metal oxide particles is 50 nm or more, the metal oxide particles provide an appropriate unevenness, which stabilizes the posture of the cleaning blade during cleaning and improves cleaning performance. In addition, when the number average primary particle diameter of the metal oxide particles is 500 nm or less, the protrusions are too large to be caught by the cleaning blade, so there is little risk of deterioration in cleaning performance due to stick-slip of the blade. .

In this specification, the number average primary particle size of metal oxide particles is defined as the number average primary particle size measured by the following method.

First, a 10,000-fold enlarged photograph taken with a scanning electron microscope (manufactured by JEOL Ltd.) is loaded into a scanner. Next, from the obtained photographic image, 300 particle images excluding agglomerated particles were randomly analyzed using an automatic image processing analysis system Luzex (registered trademark) AP software Ver. 1. 32 (manufactured by Nireco Co., Ltd.) is used to perform binarization processing to calculate the horizontal Feret diameter of each particle image. Then, the average value of the Feret diameters in the horizontal direction of each of the particle images is calculated as the number average primary particle diameter. Here, the horizontal Feret diameter refers to the length of the side parallel to the x-axis of the circumscribed rectangle obtained by binarizing the particle image. Also, the number average primary particle size of the metal oxide particles is measured for metal oxide particles that do not contain chemical species (coating layer) derived from the surface treatment agent.

At least one of the metal oxide particles according to the present invention is surface-treated with a surface treatment agent. The surface treatment agent is not particularly limited, but examples include a silicone surface treatment agent having a silicone chain, a surface treatment agent having a polymerizable functional group, and the like. ) is preferred.

The silicone surface treatment agent is not particularly limited, but preferably has a silicone chain in the side chain of the polymer main chain, and more preferably has a reactive functional group. Reactive functional groups include carboxylic acid groups, hydroxyl groups, —Rd—COOH (Rd is a divalent hydrocarbon group), alkylsilyl groups, halogenated silyl groups, and metal oxide particles such as alkoxysilyl groups. possible groups. Among these, a carboxylic acid group, a hydroxyl group or an alkoxysilyl group is preferred.

The polymer main chain of the silicone surface treatment agent is preferably a poly(meth)acrylate main chain or a silicone main chain, more preferably a silicone main chain. Metal oxide particles surface-treated with a surface-treating agent having silicone chains in both the main chain and side chains have more silicone chains, so that the dispersibility in the outermost layer is further enhanced, and the outermost layer is more durable. Abrasion resistance is further improved.

The side chain and the silicone chain of the main chain preferably have a dimethylsiloxane structure as a repeating unit, and the number of repeating units is preferably 3 to 100, more preferably 3 to 50. Thirty is more preferred.

Although the weight average molecular weight of the silicone surface treatment agent is not particularly limited, it is preferably 1,000 or more and 50,000 or less. The weight average molecular weight of the silicone surface treatment agent can be measured by gel permeation chromatography (GPC).

The silicone surface treatment agents can be used alone or in combination of two or more. Also, the silicone surface treatment agent may be a synthetic product or a commercially available product. Specific examples of commercially available surface treatment agents having a silicone chain in the side chain of the poly(meth)acrylate main chain include Saimac (registered trademark) US-350 (manufactured by Toagosei Co., Ltd.), KP-541, and KP. -574, and KP-578 (manufactured by Shin-Etsu Chemical Co., Ltd.). Specific examples of commercially available surface treatment agents having a silicone chain in the side chain of the silicone main chain include KF-9908 and KF-9909 (manufactured by Shin-Etsu Chemical Co., Ltd.).

In addition, the above metal oxide particles are particles (composite particles) having a core-shell structure having a core made of a metal oxide and an outer shell made of a surface treatment agent. is preferred. When the particle diameter of a single particle that does not have a core-shell structure is increased, the difference in refractive index with the polymerizable monomer increases, and the transmission of active energy rays (especially ultraviolet rays) used for curing the outermost layer is reduced. diminished sexuality. As a result, the film strength of the outermost layer after curing may be insufficient. Therefore, by providing a core material, it is possible to reduce the sea area by improving the dispersibility and secure the film strength by improving the light transmission.

The material constituting the core of the composite particles is not particularly limited, and examples thereof include barium sulfate, alumina, and silicon oxide. Among these, particles having barium sulfate as a core material are preferable from the viewpoint of ensuring the light transmittance of the outermost layer. In addition, the material constituting the outer shell (shell) of the composite particles is the same as those given as examples of the metal oxides constituting the metal oxide particles. Preferred examples of composite particles having a core-shell structure include composite particles having a core made of barium sulfate and an outer shell made of tin oxide. The ratio between the number-average primary particle size of the core material and the thickness of the outer shell may be appropriately set according to the types of core material and outer shell used and their combination.

- Surface treatment method with a surface treatment agent (silicone surface treatment agent) The surface treatment method with a surface treatment agent is not particularly limited, and is a method that allows the surface treatment agent to adhere (or bond) to the surface of the metal oxide particles. If it is Such methods are generally classified into two types, a wet processing method and a dry processing method, and either method may be used.

When the metal oxide particles after the reactive surface treatment, which will be described later, are subjected to surface treatment, the surface treatment agent adheres (or bonds) to the surface of the metal oxide particles or to the reactive surface treatment agent.

The wet treatment method is a method in which the metal oxide particles and the surface treatment agent are dispersed in a solvent so that the surface treatment agent adheres (or bonds) to the surface of the metal oxide particles. The method is preferably a method of dispersing the metal oxide particles and the surface treatment agent in a solvent, drying the resulting dispersion to remove the solvent, and then further heat-treating to separate the surface treatment agent and the metal. More preferred is the method of attaching (or bonding) the surface treatment agent onto the surface of the metal oxide particles by reacting with the oxide particles. Moreover, after dispersing the surface treatment agent and the metal oxide particles in a solvent, the resulting dispersion may be subjected to wet pulverization to make the metal oxide particles finer and simultaneously to advance the surface treatment.

The means for dispersing the metal oxide particles and the surface treatment agent in the solvent is not particularly limited and known means can be used. Examples thereof include general dispersing means such as homogenizers, ball mills and sand mills. be able to.

The solvent is not particularly limited and known solvents can be used. Preferred examples thereof include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol (2-butanol), tert-butanol, Examples include alcohol solvents such as benzyl alcohol, and aromatic hydrocarbon solvents such as toluene and xylene. These may be used alone or in combination of two or more. Among these, more preferred are methanol, 2-butanol, toluene, and a mixed solvent of 2-butanol and toluene.

Although the dispersion time is not particularly limited, it is preferably 1 minute or more and 600 minutes or less, more preferably 10 minutes or more and 360 minutes or less, and more preferably 30 minutes or more and 120 minutes or less.

A method for removing the solvent is not particularly limited, and a known method can be used. Examples thereof include a method using an evaporator, a method of volatilizing the solvent at room temperature, and the like.

The heating temperature is not particularly limited, but is preferably 50° C. or higher and 250° C. or lower, more preferably 70° C. or higher and 200° C. or lower, and even more preferably 90° C. or higher and 150° C. or lower. The heating time is not particularly limited, but is preferably 1 minute or more and 600 minutes or less, more preferably 10 minutes or more and 300 minutes or less, and even more preferably 30 minutes or more and 90 minutes or less. A heating method is not particularly limited, and a known method can be used.

The dry treatment method is a method of adhering (or bonding) the surface treatment agent to the surface of the conductive metal oxide by mixing and kneading the surface treatment agent and metal oxide particles without using a solvent. be. In this method, the surface treatment agent and the metal oxide particles are mixed and kneaded, and then heat-treated to react the surface treatment agent and the metal oxide particles, thereby converting the surface treatment agent into a metal oxide. It may be a method of adhering (or bonding) on the surface of the particles. In addition, when the metal oxide particles and the surface treatment agent are mixed and kneaded, they may be dry-pulverized to make the metal oxide particles finer and simultaneously advance the surface treatment.

The amount of the surface treatment agent used is 100 parts by mass of the metal oxide particles before treatment (the metal oxide particles after the reactive surface treatment when the metal oxide particles after the reactive surface treatment described below are surface-treated). On the other hand, it is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more. Within this range, the abrasion resistance of the outermost layer and the anti-fogging effect are further improved.

In addition, the amount of the surface treatment agent used is 100 of the metal oxide particles before the surface treatment (the metal oxide particles after the reactive surface treatment when the metal oxide particles after the reactive surface treatment described below are surface-treated). It is preferably 100 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less. Within this range, the decrease in film strength of the outermost layer due to unreacted surface treatment agent is suppressed, and the abrasion resistance of the outermost layer is improved.

The surface treatment of untreated metal oxide particles or metal oxide particles after reactive surface treatment can be confirmed by thermogravimetric and differential thermal (TG/DTA) measurements, scanning electron microscopy (SEM) or transmission electron microscopy. It can be confirmed by observation with a microscope (TEM), analysis by energy dispersive X-ray spectroscopy (EDX), or the like.

The surface-treated particles preferably have groups derived from polymerizable groups. The abrasion resistance of the outermost layer is improved by the surface-treated particles having a group derived from a polymerizable group. The reason for this is presumed to be that the surface-treated particles and the polymerizable monomer are in a state of being chemically bonded in the cured product constituting the outermost layer, thereby improving the film strength of the outermost layer. Although the type of the polymerizable group is not particularly limited, radically polymerizable groups are preferred. The method for introducing the polymerizable group is not particularly limited, but a method of surface-treating the metal oxide particles with a surface-treating agent having a polymerizable group is preferable.

The fact that the surface-treated particles have a polymerizable group and that the surface-treated particles in the outermost layer have a group derived from a polymerizable group can be confirmed by thermogravimetric/differential thermal (TG/DTA) measurement and scanning electron microscope (SEM). Alternatively, it can be confirmed by observation with a transmission electron microscope (TEM), analysis by energy dispersive X-ray spectroscopy (EDX), mass spectrometry, or the like.

- A surface treatment method using a surface treatment agent having a polymerizable group (reactive surface treatment agent) The metal oxide particles subjected to the surface treatment (silicone surface treatment) described above are further surface treated with a reactive surface treatment agent. is preferred. The polymerizable groups are carried on the surface of the metal oxide particles by reactive surface treatment, and as a result, the surface-treated particles further have polymerizable groups. Then, in the outermost layer, the surface-treated particles are polymerized with the polymerizable monomer through the polymerizable group, forming the outermost layer with higher film strength and further improving the abrasion resistance of the outermost layer. At this time, the silicone surface-treated particles exist as a structure having a group derived from a polymerizable group in the outermost layer.

A reactive surface treatment agent has a polymerizable group and a reactive functional group. Although the type of the polymerizable group is not particularly limited, radically polymerizable groups are preferred. Here, the radically polymerizable group represents a radically polymerizable group having a carbon-carbon double bond. Examples of radically polymerizable groups include vinyl groups and (meth)acryloyl groups, among which methacryloyl groups are preferred. Moreover, the reactive functional group represents a group having reactivity with a polar group such as a hydroxyl group present on the surface of the metal oxide particles. Examples of reactive functional groups include carboxylic acid groups, hydroxyl groups, —R′—COOH (R′ is a divalent hydrocarbon group), alkylsilyl groups, halogenated silyl groups, alkoxysilyl groups, and the like. Among these, alkylsilyl groups, halogenated silyl groups, and alkoxysilyl groups are preferred.

The reactive surface treatment agent is preferably a silane coupling agent having a radically polymerizable group, and examples thereof include compounds represented by the following formulas S-1 to S-32.
S-1: CH ₂ =CHSi(CH ₃ )(OCH ₃ ) ₂
S-2: _CH2 =CHSi( _OCH3 ) ₃
S-3: _CH2 = _CHSiCl3
S-4: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 )( _OCH3 ) ₂
S-5: _CH2 =CHCOO( _CH2 ) _2Si ( _OCH3 ) ₃
S-6: _CH2 =CHCOO( _CH2 ) _{2Si ( OC2H5} )( _OCH3 ) ₂
S-7: _CH2 =CHCOO( _CH2 ) _3Si ( _OCH3 ) ₃
S-8: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 ) _Cl2
S-9: _CH2 =CHCOO _{( CH2} ) _2SiCl3
S-10: _CH2 =CHCOO( _CH2 ) _3Si ( _CH3 ) _Cl2
S -11: _CH2 =CHCOO( _CH2 ) _3SiCl3
S-12: _CH2 =C( _CH3 )COO( _CH2 ) _2Si ( _CH3 )( _OCH3 ) ₂
S-13: _CH2 =C( _CH3 )COO( _CH2 ) _2Si ( _OCH3 ) ₃
S-14: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _CH3 )( _OCH3 ) ₂
S-15: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _OCH3 ) ₃
S-16: _CH2 =C( _CH3 )COO( _CH2 ) _2Si ( _CH3 ) _Cl2
S-17: _CH2 =C( _CH3 ) _COO ( _CH2 ) _2SiCl3
S-18: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _CH3 ) _Cl2
S-19: _CH2 =C( _CH3 ) _COO ( _CH2 ) _3SiCl3
S-20 _{: CH2} =CHSi( _C2H5 )( _OCH3 ) ₂
S-21: _CH2 =C( _CH3 )Si( _OCH3 ) ₃
S- ₂₂ : _CH2 =C( _CH3 )Si( _OC2H5 ) ₃
S-23: _CH2 =CHSi( _OCH3 ) ₃
S-24: _CH2 =C( _CH3 )Si( _CH3 )( _OCH3 ) ₂
S-25: _CH2 =CHSi( _CH3 ) _Cl2
S-26: _CH2 =CHCOOSi( _OCH3 ) ₃
S-27: _CH2 = _CHCOOSi ( _OC2H5 ) ₃
S-28: _CH2 =C( _CH3 )COOSi( _OCH3 ) ₃
S- ₂₉ : _CH2 =C( _CH3 )COOSi( _OC2H5 ) ₃
S- ₃₀ : _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _OC2H5 ) ₃
S-31: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 ) ₂ ( _OCH3 )
S-32: _CH2 =C( _CH3 )COO( _CH2 ) _8Si ( _OCH3 ) ₃

Reactive surface treatment agents can be used alone or in combination of two or more. Also, the reactive surface treatment agent may be a synthetic product or a commercially available product. Specific examples of commercially available products include KBM-502, KBM-503, KBE-502, KBE-503, and KBM-5103 (manufactured by Shin-Etsu Chemical Co., Ltd.).

When performing both silicone surface treatment and reactive surface treatment, it is preferable to perform silicone surface treatment after performing reactive surface treatment. By performing the surface treatment in this order, the wear resistance of the outermost layer is further improved. The reason for this is that the silicone chains having an oil-repellent effect do not prevent the contact of the reactive surface treatment agent with the metal oxide particle surface, so that the introduction of the polymerizable group into the metal oxide particles is more efficient. for it is done.

The method of reactive surface treatment is not particularly limited, and the same methods as those described for the silicone surface treatment can be employed except that a reactive surface treatment agent is used. Also, a known surface treatment technique for metal oxide particles may be used.

When using a reactive surface treatment by a wet treatment method, the solvent is preferably methanol, ethanol or toluene, more preferably methanol or toluene.

The amount of the reactive surface treatment agent used is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the metal oxide particles before the reactive surface treatment. It is more preferably 1.5 parts by mass or more. Within this range, the wear resistance and anti-fogging effect of the outermost layer are further improved. The amount of the reactive surface treatment agent used is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and 8 parts by mass with respect to 100 parts by mass of the metal oxide particles before treatment. More preferably: Within this range, the amount of the reactive surface treatment agent does not become excessive with respect to the number of hydroxyl groups on the particle surface, and it is a more appropriate range, and the decrease in the film strength of the outermost layer due to the unreacted reactive surface treatment agent does not occur. It is suppressed, and the wear resistance of the outermost layer is further improved.

<Polymerizable Monomer>
The resin composition for forming the outermost layer contains a polymerizable monomer. In this specification, the polymerizable monomer has a polymerizable group, and is polymerized (cured) by irradiation with active energy rays such as ultraviolet rays, visible light, and electron beams, or by addition of energy such as heating. It represents a compound that becomes the binder resin of the outermost layer. The term "polymerizable monomer" as used herein does not include the above-mentioned reactive surface treatment agent. shall not be included.

Although the type of polymerizable group possessed by the polymerizable monomer is not particularly limited, a radically polymerizable group is preferred. Here, the radically polymerizable group represents a radically polymerizable group having a carbon-carbon double bond. Examples of radically polymerizable groups include vinyl groups and (meth)acryloyl groups, with (meth)acryloyl groups being preferred. When the polymerizable group is a (meth)acryloyl group, the wear resistance and antifogging effect of the outermost layer are improved. It is presumed that the reason for the improvement in abrasion resistance of the outermost layer is that efficient curing can be achieved with a small amount of light or a short time.

Examples of polymerizable monomers include styrene-based monomers, (meth)acrylic-based monomers, vinyltoluene-based monomers, vinyl acetate-based monomers, and N-vinylpyrrolidone-based monomers. These polymerizable monomers can be used alone or in combination of two or more.

The number of polymerizable groups in one molecule of the polymerizable monomer is not particularly limited, but is preferably 2 or more, more preferably 3 or more. Within this range, the wear resistance of the outermost layer is improved. The reason for this is presumed to be that the crosslink density of the outermost layer increases and the film strength is further improved. Further, the number of polymerizable groups in one molecule possessed by the polymerizable monomer is not particularly limited, but is preferably 6 or less, more preferably 5 or less, and further preferably 4 or less. preferable. Within this range, the uniformity of the outermost layer is enhanced, and the effect of suppressing fogging is enhanced. The reason for this is presumed to be that the crosslink density is below a certain level, and cure shrinkage is less likely to occur. From these points of view, the number of polymerizable groups in one molecule of the polymerizable monomer is most preferably three.

Specific examples of the polymerizable monomer include, but are not particularly limited to, the following compounds M1 to M11. Among them, the following compound M2 is particularly preferred. In each formula below, R represents an acryloyl group (CH ₂ =CHCO-) and R' represents a methacryloyl group (CH ₂ =C(CH ₃ )CO-).

The polymerizable monomers may be used alone or in combination of two or more. Moreover, the polymerizable monomer may be a synthetic product or a commercially available product.

<Polymerization initiator>
The resin composition for forming the outermost layer preferably further contains a polymerization initiator. The polymerization initiator is used in the process of producing a curable resin (binder resin) obtained by polymerizing the polymerizable monomers. The polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator, but is preferably a photopolymerization initiator. Moreover, when the polymerizable monomer is a radically polymerizable monomer, it is preferably a radical polymerization initiator. The radical polymerization initiator is not particularly limited, and known ones can be used, and examples thereof include alkylphenone-based compounds and phosphine oxide-based compounds. Among these, compounds having an α-aminoalkylphenone structure or an acylphosphine oxide structure are preferred, and compounds having an acylphosphine oxide structure are more preferred. An example of a compound having an acylphosphine oxide structure is IRGACURE (registered trademark) 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) (manufactured by BASF Japan Ltd.).

These polymerization initiators may be used alone or in combination of two or more.

The amount of the polymerization initiator used is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, per 100 parts by mass of the polymerizable monomer.

<Charge transport material>
The resin composition for forming the outermost layer may further contain a charge transport material. The charge transport material is not particularly limited, and known materials can be used. Examples include 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, oxazolones. derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives and the like. Among these, triarylamine derivatives are preferred. As the triarylamine derivative, one represented by the following chemical formula 1 is preferable.

In Chemical Formula 1, R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 7 carbon atoms or an alkoxy group having 1 to 7 carbon atoms. k, l and n each independently represent an integer of 0-5, and m represents an integer of 0-4. However, when k, l, n or m is 2 or more, a plurality of R ₁ , R ₂ , R ₃ and R ₄ may be the same or different. . Among these, R ₁ , R ₂ , R ₃ and R ₄ are each independently preferably an alkyl group having 1 to 3 carbon atoms. Also, k, l, n and m are each independently preferably an integer of 0 to 1.

As the compound represented by the chemical formula 1, for example, those described in JP-A-2015-114454 can be used, and a known synthesis method, for example, the method disclosed in JP-A-2006-143720. etc. can be synthesized.

<Other ingredients>
The resin composition for forming the outermost layer may further contain components other than the components described above. Examples of other components include, but are not particularly limited to, lubricants and the like when the outermost layer is a protective layer. There are no particular restrictions on the lubricant, and any known lubricant can be used, examples of which include polymerizable silicone compounds and polymerizable perfluoropolyether compounds.

(Manufacturing method of electrophotographic photoreceptor)
The electrophotographic photoreceptor according to one embodiment of the present invention is not particularly limited except that the resin composition for forming the outermost layer containing the resin composition for forming the outermost layer according to the present invention is used. can be manufactured by the manufacturing method of Among them, a step of applying a coating liquid containing a resin composition for forming an outermost layer to the surface of a photosensitive layer formed on a conductive support, and exposing the applied resin composition for forming an outermost layer to an active energy ray. or heating the coated resin composition for forming the outermost layer to obtain a cured product of the resin composition for forming the outermost layer.

The resin composition for forming the outermost layer includes a resin composition for forming the outermost layer containing a polymerizable monomer and metal oxide particles (and/or surface-treated particles). The resin composition for forming the outermost layer may further contain other components such as a polymerization initiator. In addition, the resin composition for forming the outermost layer can contain a dispersion medium.

As the dispersion medium used in the resin composition for forming the outermost layer, a polymerizable monomer, metal oxide particles (and/or surface-treated particles), and a polymerization initiator to be added as necessary are dissolved or dispersed. You can use any of them if you can. Specifically, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol (sec-butanol), tert-butanol, benzyl alcohol, toluene, xylene, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate , methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1,3-dioxane, 1,3-dioxolane, pyridine and diethylamine. The dispersion medium can be used alone or in combination of two or more.

The content of the dispersion medium with respect to the total mass of the resin composition for forming the outermost layer is not particularly limited, but is preferably 1% by mass or more and 99% by mass or less, and preferably 40% by mass or more and 90% by mass or less. More preferably, it is 50% by mass or more and 80% by mass or less.

The content of the polymerizable monomer in the resin composition for forming the outermost layer is not particularly limited, but is preferably 30% by mass or more, more preferably 40% by mass or more, and 50% by mass or more. is more preferred. Within this range, the crosslink density of the outermost layer is increased, the film strength is further improved, and the wear resistance of the outermost layer is further improved. The content of the polymerizable monomer in the resin composition for forming the outermost layer is not particularly limited, but is preferably 80% by mass or less, more preferably 70% by mass or less, and 60% by mass or less. is more preferable.

The content of the metal oxide particles in the resin composition for forming the outermost layer is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, and 40% by mass or more. It is even more preferable to have Within this range, the crosslink density of the outermost layer is increased, the mechanical strength is further improved, and the abrasion resistance of the outermost layer is further improved. The content of the polymerizable monomer in the resin composition for forming the outermost layer is not particularly limited, but is preferably 70% by mass or less, more preferably 60% by mass or less, and 50% by mass or less. is more preferable.

When the resin composition for forming the outermost layer contains a polymerization initiator, the content is not particularly limited, but it is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the polymerizable monomer. It is more preferably 5 parts by mass or more, and even more preferably 5 parts by mass or more. Within this range, the wear resistance of the outermost layer is improved. The reason for this is that the crosslink density of the outermost layer is increased, the mechanical strength is further improved, and the abrasion resistance of the outermost layer is further improved. The content of the polymerization initiator in the resin composition for forming the outermost layer is not particularly limited, but is preferably 40 parts by mass or less, and 30 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. more preferably 20 parts by mass or less.

The method of preparing the resin composition for forming the outermost layer is also not particularly limited, and various additives such as polymerizable monomers, metal oxide particles, and optionally a polymerization initiator are added to the dispersion medium, Stir and mix until dissolved or dispersed.

The outermost layer according to the present invention can be formed by applying the resin composition for forming the outermost layer prepared by the above method onto the photosensitive layer, followed by drying and curing.

In the process of coating, drying, and curing, the reaction between the polymerizable monomers, the reaction between the polymerizable monomer and the reactive surface-treated metal oxide particles, and the reaction between the reactive surface-treated metal oxide particles. Reaction and the like proceed to form the outermost layer (protective layer) containing the cured resin composition for forming the outermost layer.

The method of applying the resin composition for forming the outermost layer is not particularly limited, and examples thereof include dip coating, spray coating, spinner coating, bead coating, blade coating, beam coating, slide hopper coating, and circular coating. A known method such as a slide hopper coating method can be used.

After the application of the coating liquid, natural drying or heat drying is performed to form a coating film, which is then cured by irradiating active energy rays. As the active energy ray, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, flash (pulse) xenon lamps, and the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of ultraviolet rays (accumulated light amount) is preferably 5 to 5000 mJ/cm ² , more preferably 10 to 2000 mJ/cm ² . The illuminance of ultraviolet rays is preferably 5-500 mW/cm ² , more preferably 10-100 mW/cm ² .

The irradiation time for obtaining the necessary irradiation dose (integrated light dose) of active energy rays is preferably 0.1 seconds to 10 minutes, more preferably 0.1 seconds to 5 minutes from the viewpoint of work efficiency.

In the process of forming the protective layer, drying can be performed before and after irradiation with active energy rays, or during irradiation with active energy rays, and the timing of drying can be appropriately selected by combining these.

Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably 20 to 180°C, more preferably 80 to 140°C, and the drying time is preferably 1 to 200 minutes, more preferably 5 to 100 minutes.

The thickness of the outermost layer is preferably 1 to 10 μm, more preferably 1.5 to 5 μm.

In addition, the fact that the outermost layer contains a cured product of the above composition is performed by known analysis methods such as pyrolysis GC-MS, nuclear magnetic resonance (NMR), Fourier transform infrared spectrophotometer (FT-IR), and elemental analysis. can be confirmed by

[Lubricant supply means]
Lubricant supply means 116Y is means for supplying lubricant to the surface of photoreceptor 111Y. A lubricant film is formed on the surface of the photoreceptor 111Y by the lubricant supplying means 116Y. The lubricant supplying unit 116Y is arranged downstream of the lubricant removing unit 114Y and upstream of the charging unit 113Y in the rotation direction of the photoreceptor 111Y.

The lubricant supply means 116Y in this example is composed of a solid lubricant and an application member consisting of a brush roller. Specifically, as shown in FIG. 2, the lubricant supply means 116Y includes a housing 20, a lubricant stock 22 accommodated in the housing 20 and made of solid lubricant having a cuboid shape, A brush roller 21 that contacts the surface of the photoreceptor 111Y and rubs the surface of the lubricant stock 22 to apply the scraped lubricant to the surface of the photoreceptor 111Y; , and a driving mechanism (not shown) for rotating the brush roller 21 . The tip of the brush roller 21 is in contact with the surface of the photoreceptor 111Y. In addition, the brush roller 21 is rotationally driven at a constant speed in a direction opposite to the rotational direction of the photoreceptor 111Y.

As the brush roller 21, for example, a bundle of fibers is woven into the base fabric as pile threads to form a ribbon-like fabric, which is spirally wound around a metal shaft with the raised surface facing outward and adhered. is mentioned. The brush roller 21 of this example is formed on the peripheral surface of the roller base with a long woven fabric in which brush fibers made of a resin such as polypropylene are planted at a high density.

From the viewpoint of coating ability, the straight bristles of the bristles are preferably raised in the direction perpendicular to the metal shaft. The thread used for brush bristles is preferably a filament thread, and the material includes synthetic resins such as 6-nylon, 12-nylon, polyester, acrylic, and vinylon. Metals such as carbon and nickel are used for the purpose of increasing conductivity. It may be kneaded. The thickness of the brush fiber is, for example, 3 to 7 denier, the hair length of the brush fiber is 2 to 5 mm, the electric resistivity of the brush fiber is 1×10 ¹⁰ Ω or less, the Young's modulus of the brush fiber is 4900 to 9800 N/mm ² , The fiber planting density (the number of brush fibers per unit area) is preferably, for example, 50,000 to 200,000/square inch (50k to 200k/inch ² ). The amount of bite of the brush roller 21 into the photosensitive member is preferably 0.5 to 1.5 mm. The rotation speed of the brush roller is, for example, 0.3 to 1.5 relative to the peripheral speed of the photoreceptor, and may rotate in the same direction as or in the opposite direction to the rotation direction of the photoreceptor.

The pressure spring 23 presses the lubricant stock 22 toward the photoreceptor 111Y so that the pressing force of the brush roller 21 against the photoreceptor 111Y is, for example, 0.5 to 1.0N.

In the lubricant supplying means 116Y, for example, the brush roller of the lubricant stock ²² is used so that the coating amount per 1 cm ² of the surface of the photoreceptor 111Y is 0.5×10 ⁻⁷ to 1.5×10 ⁻⁷ g/cm 2 . 21 and the rotation speed of the brush roller 21 are adjusted.

[Fatty acid metal salt]
Lubricants include fatty acid metal salts. As the fatty acid metal salt, for example, zinc oleate, zinc stearate, calcium stearate and the like can be used. Among these, it is preferable to use zinc stearate from the viewpoint of lubricity and spreadability. These can be used individually by 1 type or in combination of 2 or more types.

The number average particle size of the powdery fatty acid metal salt used as a raw material is preferably 500 μm or less, more preferably 0.5 to 40 μm. If the number average particle diameter is 500 µm or less, there is little possibility that the moldability will deteriorate when producing a solid lubricant stock.

[boron nitride]
The lubricant further includes boron nitride. The number average particle size of boron nitride is preferably 0.07 to 500 μm, more preferably 0.5 to 40 μm.

When boron nitride having a number average particle size of 0.07 μm or more is used, sufficient lubricity can be obtained. Further, when boron nitride having a number average particle size of 500 μm or less is used, there is little possibility that the formability of the solid lubricant stock will be deteriorated.

The content ratio of boron nitride in the lubricant is preferably in the range of Mb/Ma from 50/50 to 1/99, more preferably from 50/50 to 1/99, where Ma is the mass of the fatty acid metal salt and Mb is the mass of the boron nitride. 50/50 to 5/95. When the content of boron nitride in the lubricant is 1% by mass or more (that is, Mb/Ma=1/99), it is possible to prevent lubricant memory, which increases the image density of the non-striped area. Further, when the content is 50% by mass or less (that is, Mb/Ma = 50/50), the lubricant can be sufficiently removed by the lubricant removing means, and the occurrence of filming due to the lubricant on the surface of the photoreceptor can be suppressed. can do.

[Inorganic lubricant]
The lubricant may contain an inorganic lubricant other than boron nitride as long as it does not interfere with the effects of the present invention. As such an inorganic lubricant, it is preferable to use a substance having a cleavage property, and examples thereof include molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, and mica. Among these, it is preferable to use boron nitride. These can be used individually by 1 type or in combination of 2 or more types.

[Charging means]
The charging unit 113Y is a unit that charges the surface of the photoreceptor 111Y with a charging roller. The charging means 113Y in this example comprises a charging roller arranged in contact with the surface of the photoreceptor 111Y and a power supply for applying voltage to the charging roller.

In the present invention, the charging means employs a proximity charging method in which charging is performed while the charging roller is in contact with or close to the surface of the photoreceptor.

As shown in FIG. 3, the charging roller 11 includes an elastic layer 11b laminated on the surface of the core metal 11a for reducing charging noise and imparting elasticity to obtain uniform adhesion to the photoreceptor 111Y. A resistance control layer 11c is laminated on the surface of the charging roller 11 as necessary to obtain a highly uniform electric resistance as a whole, and a surface layer 11d is laminated on the resistance control layer 11c, The photosensitive member 111Y is biased in the direction of the photosensitive member 111Y by the pressing spring 11e and pressed against the surface of the photosensitive member 111Y with a predetermined pressing force to form a charging nip portion. is rotated following the rotation of .

The metal core 11a is, for example, metals such as iron, copper, stainless steel, aluminum and nickel, or the surfaces of these metals are plated to the extent that the electrical conductivity is not impaired in order to obtain rust prevention and scratch resistance. and has an outer diameter of, for example, 3 to 20 mm.

The elastic layer 11b is made of, for example, an elastic material such as rubber to which conductive fine particles such as carbon black or carbon graphite or conductive salt fine particles such as alkali metal salt or ammonium salt are added. Specific examples of elastic materials include natural rubber, ethylene propylene diene methylene rubber (EPDM), styrene-butadiene rubber (SBR), silicone rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), and butadiene rubber (BR). , synthetic rubbers such as nitrile-butadiene rubber (NBR) and chloroprene rubber (CR); resins such as polyamide resins, polyurethane resins, silicone resins and fluorine resins; and foams such as foamed sponges. The amount of elasticity can be adjusted by adding process oils, plasticizers, etc. into the elastic material.

The elastic layer 11b preferably has a volume resistivity in the range of 1×10 ¹ to 1×10 ¹⁰ Ω·cm. Also, the layer thickness is preferably 500 to 5000 μm, more preferably 500 to 3000 μm.
The volume resistivity of the elastic layer 11b is a value measured according to JIS K6911.

The resistance control layer 11c is provided for the purpose of making the charging roller 11 as a whole have a uniform electric resistance, but it is not necessary. This resistance control layer 11c can be provided by coating a material having appropriate conductivity or covering a tube having appropriate conductivity.

Specific materials constituting the resistance control layer 11c include resins such as polyamide resins, polyurethane resins, fluororesins, and silicone resins; basic materials such as rubbers such as epichlorohydrin rubbers, urethane rubbers, chloroprene rubbers, and acrylonitrile rubbers; conductive fine particles such as carbon black and carbon graphite; conductive metal oxide fine particles such as conductive titanium oxide, conductive zinc oxide, and conductive tin oxide; conductive fine particles such as alkali metal salts and ammonium salts; Examples include those to which a conductive agent such as salt fine particles is added.

The resistance control layer 11c preferably has a volume resistivity in the range of 1×10 ⁻² to 1×10 ¹⁴ Ω·cm, more preferably 1×10 ¹ to 1×10 ¹⁰ Ω·cm. Also, the layer thickness is preferably 0.5 to 100 μm, more preferably 1 to 50 μm, further preferably 1 to 20 μm.
The volume resistivity of the resistance control layer 11c is a value measured according to JIS K6911.

The surface layer 11d is provided for the purpose of preventing the plasticizer in the elastic layer 11b from bleeding out onto the surface of the charging roller obtained, or for the purpose of obtaining slipperiness or smoothness on the surface of the charging roller, or for the purpose of preventing pins on the photoreceptor 10. It is provided for the purpose of preventing leakage even if there is a defect such as a hole, and is coated with a material having appropriate conductivity, or covered with a tube having moderate conductivity. It is established by

When the surface layer 11d is provided by coating materials, specific materials include resins such as polyamide resin, polyurethane resin, acrylic resin, fluororesin and silicone resin, epichlorohydrin rubber, urethane rubber, chloroprene rubber and acrylonitrile rubber. A conductive agent such as conductive fine particles made of carbon black, carbon graphite, etc.; conductive metal oxide fine particles made of conductive titanium oxide, conductive zinc oxide, conductive tin oxide, etc. things are mentioned. Examples of coating methods include dip coating, roll coating, and spray coating.

Further, when the surface layer 11d is provided by coating a tube, as a specific tube, nylon 12, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), polyvinylidene fluoride, tetrafluoroethylene-6 Polypropylene fluorinated copolymer resin (FEP): Thermoplastic elastomer such as polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyester, and polyamide to which the above-mentioned conductive agent is added is molded into a tubular shape. What was done is mentioned. This tube may be heat-shrinkable or non-heat-shrinkable.

The surface layer 11d preferably has a volume resistivity in the range of 1×10 ¹ to 1×10 ⁸ Ω·cm, more preferably 1×10 ¹ to 1×10 ⁵ Ω·cm. Also, the layer thickness is preferably 0.5 to 100 μm, more preferably 1 to 50 μm, further preferably 1 to 20 μm.
The volume resistivity of the surface layer 11d is a value measured according to JIS K6911.

The surface layer 11d preferably has a surface roughness Rz of 1 to 30 μm, more preferably 2 to 20 μm, still more preferably 5 to 10 μm.

In the charging roller 11 as described above, the surface of the photoreceptor 111Y is charged to a predetermined potential with a predetermined polarity by applying a charging bias voltage from the power supply S1 to the metal core 11a of the charging roller 11. FIG. Here, the charging bias voltage may be, for example, only a DC voltage, but it is preferable to use an oscillating voltage in which an AC voltage is superimposed on a DC voltage because charging uniformity is excellent.
The charging bias voltage can be, for example, about -2.5 to -1.5 kV.

An example of charging conditions by the charging roller 11 shown in FIG. 3 is as follows. , the surface of the photoreceptor 10 is uniformly charged to -500 V by applying this charging bias voltage.

[Exposure means]
The exposure unit 115Y exposes the surface of the photoreceptor 111Y to which a uniform potential is applied by the charging unit 113Y based on an image signal (yellow image signal) to form an electrostatic latent image corresponding to the yellow image. It is a means to The exposure means 115Y is composed of an LED in which light-emitting elements are arranged in an array in the axial direction of the photoreceptor 111Y and an imaging element, or a laser optical system or the like is used.

[Development means]
The developing means 117Y is means for supplying toner to the surface of the photoreceptor 111Y and developing an electrostatic latent image formed on the surface of the photoreceptor 111Y to form a toner image. Specifically, the developing means 117Y in this example includes a developing sleeve that incorporates a magnet and holds a developer and rotates, and a voltage application that applies a DC and/or AC bias voltage between the photosensitive member and the developing sleeve. It consists of a device.

[Transfer Means]
A primary transfer roller 133</b>Y forming a transfer unit is a unit that transfers the toner image formed on the photoreceptor 111</b>Y to the endless belt-like intermediate transfer member 131 . The primary transfer roller 133Y is arranged in contact with the intermediate transfer member 131. As shown in FIG.

In this image forming apparatus 100, the toner images formed on the photosensitive members 111Y, 111M, 111C, and 111Bk are transferred onto the intermediate transfer member 131 by primary transfer rollers (primary transfer means) 133Y, 133M, 133C, and 133Bk. An intermediate transfer method is adopted in which each toner image transferred on the transfer body 131 is transferred onto the transfer material P by a secondary transfer roller (secondary transfer means) 217. A direct transfer method may be adopted in which the image is directly transferred onto the transfer material by a transfer means.

[Cleaning means]
The cleaning unit 119Y is a unit for removing toner remaining on the surface of the photoreceptor 111Y. The cleaning means 119Y in this example is composed of a cleaning blade. As shown in FIG. 2, this cleaning blade comprises a support member 31 and a blade member 30 supported on the support member 31 via an adhesive layer (not shown). The blade member 30 is arranged such that its tip faces in the opposite direction (counter direction) to the rotation direction of the photoreceptor 111Y at the contact portion with the surface of the photoreceptor 111Y.

The support member 31 is not particularly limited, and conventionally known members can be used. Examples thereof include those made of rigid metal, elastic metal, plastic, ceramic, and the like. Among them, a rigid metal is preferable.

As the blade member 30, for example, a multi-layer structure in which a base layer and an edge layer are laminated can be used. The base layer and the edge layer are each preferably composed of polyurethane. Polyurethanes include those obtained by reacting polyols, polyisocyanates and, if necessary, cross-linking agents.

[Lubricant removal means]
The lubricant remover 114Y is a means for removing the lubricant attached to the surface of the photoreceptor 111Y. The lubricant removing unit 114Y is arranged downstream of the cleaning unit 119Y and upstream of the lubricant supplying unit 116Y in the rotation direction of the photoreceptor 111Y.

Lubricant removing means 114Y is preferably a means for removing the lubricant by a mechanical action when a removing member comes into contact with the surface of photoreceptor 111Y. Here, removing the lubricant by mechanical action means removing the lubricant by mechanically rubbing the surface of the photoreceptor. As the lubricant removing means, a removing member such as a brush roller or a foam roller can be used, and a brush roller is preferable from the viewpoint of removing ability and durability. Specifically, the lubricant removing means 114Y in this example includes a removing member consisting of a brush roller that contacts the surface of the photoreceptor 111Y and that is driven to rotate at a constant speed in a direction opposite to the rotation direction of the photoreceptor 111Y, and a driving mechanism. Consists of

As a brush roller as a removing member, for example, a bundle of fibers is woven into a base fabric as pile thread to form a ribbon-like fabric, which is spirally wound around a metal shaft with the raised surface facing outward. Glued ones are included. The brush roller of this example has a long woven fabric in which brush fibers made of a resin such as polyester are planted at a high density and formed on the peripheral surface of a metal shaft.

From the standpoint of removing ability, the bristles of the straight bristles are preferably raised in the direction perpendicular to the metal shaft. The thread used for brush bristles is preferably a filament thread, and the material includes synthetic resins such as 6-nylon, 12-nylon, polyester, acrylic, and vinylon. Metals such as carbon and nickel are used for the purpose of increasing conductivity. It may be kneaded. The thickness of the brush fibers is preferably 3 to 15 denier, and the hair length of the brush fibers is preferably 2 to 5 mm. In addition, by setting the planting density of the brush fibers in the range of 40,000 to 500,000/square inch (40k to 500kF/inch ² ), the rigidity necessary for removal is secured, and the sparse brush bristles are removed. Therefore, it is possible to prevent uneven removal of the lubricant from occurring. The electric resistivity of the brush fibers is preferably 1×10 ⁷ Ω or less, and the Young's modulus of the brush fibers is preferably 1500 to 9800 N/mm ² . The amount of bite of the brush roller into the photosensitive member is preferably 0.5 to 1.5 mm. The rotation speed of the brush roller is, for example, 0.3 to 1.5 in terms of the photoreceptor speed ratio, and may rotate in the same direction as or in the opposite direction to the rotation direction of the photoreceptor.

In the configuration shown in FIG. 2, a leveling blade 118Y for uniformly applying the lubricant supplied to the surface of the photoreceptor 111Y by the lubricant supplying means 116Y is provided downstream of the lubricant supplying means 116Y and upstream of the charging means 113Y. is provided.

In the image forming apparatus 100 of the present invention, A (atm %), and B (atm %) is the abundance ratio of the lubricant per unit area of the surface of the photoreceptor 111Y after the lubricant is removed by the lubricant removing unit 114Y and before the lubricant is supplied by the lubricant supplying unit 116Y. It is preferable to satisfy formulas (1) and (2).
Formula (1): A≧8B
Formula (2): A≧1.7

By satisfying both the above formulas (1) and (2), sufficient lubricant exists on the surface of the photoreceptor 111Y before charging by the charging unit 113Y, so that deterioration of the surface of the photoreceptor 111Y can be prevented. Since the resistance of the surface of the photoreceptor 111Y can be maintained high, it is possible to more reliably suppress the occurrence of image deletion in a high-temperature and high-humidity environment. Since a sufficient amount of lubricant exists on the surface of the photoreceptor 111Y, good toner cleaning properties can be reliably obtained. Furthermore, after the toner is removed by the cleaning unit 119Y, the deteriorated lubricant is removed from the surface of the photoreceptor 111Y, so the occurrence of image deletion due to deterioration of the lubricant can be more reliably suppressed.

In the measurement of the lubricant existence ratio A, any position on the surface of the rotating photoreceptor 111Y on the downstream side of the lubricant supplying means 116Y and on the upstream side of the charging means 113Y can be selected. In particular, an arbitrary portion on the surface of the photosensitive member 111Y on the downstream side of the leveling blade 118Y and the upstream side of the charging means 113Y is preferable.

In addition, in the measurement of the lubricant existence ratio B, in the rotating photoreceptor 111Y, an arbitrary portion on the surface of the photoreceptor 111Y on the downstream side of the lubricant removing means 114Y and the upstream side of the lubricant supplying means 116Y can be selected. .

Lubricant existence ratio A is set to 1.7 atm % or more, more preferably 2.0 to 2.5 atm %. Also, A/B is 8 or more, more preferably 20-30.

Here, the lubricant existence ratio means the degree of existence of the lubricant per unit area of the surface of the photoreceptor. In the present invention, the existence ratio of the metal derived from the fatty acid metal salt constituting the lubricant on the surface of the photoreceptor measured by X-ray photoelectron spectroscopy (ESCA) is used as an alternative amount. Since the ratio of the fatty acid metal salt and boron nitride in the lubricant is considered to be substantially constant over time, the abundance ratio of the metal derived from the fatty acid metal salt can be used as an alternative to the lubricant abundance ratio in the lubricant as a whole. . The unit is "atm%". The selected elements to be detected are (1) elements (C, O, etc.) of the crosslinked polymer constituting the protective layer, (2) metal oxides (such as Sn), and (3) fatty acid metals supplied to the photoreceptor surface. Metals derived from salts (for example, Zn, Al, etc.). As for these selective elements, it is necessary to extract all the elements that are thought to exist on the surface of the photoreceptor depending on the type of material forming the protective layer and the type of lubricant used. From the viewpoint of detectability, in order to differentiate between the metal derived from the metal oxide contained in the protective layer and the metal derived from the fatty acid metal salt, the metal oxide used and the metal derived from the fatty acid metal salt are Choose a different kind.

Specifically, in a high-temperature and high-humidity environment (temperature of 30° C., humidity of 80% RH), only the protective layer is cut off from the photoreceptor after printing 2000 sheets, and this is used as a measurement sample. Using an X-ray photoelectron spectrometer "K-Alpha" (manufactured by Thermo Fisher Scientific), the selected elements are quantitatively analyzed under the following measurement conditions, and the surface element concentration is determined using the relative sensitivity factor from each atomic peak area. calculate. Treat the measured quantity of the metal detected as a surrogate quantity.
Measurement conditions X-ray: Al monochrome radiation source Acceleration: 12 kV, 6 mA
Resolution: 50eV
Beam system: 400 μm
Step size: 0.1 eV

The lubricant abundance ratio A can be controlled by the amount of lubricant supplied by the lubricant supplying means and the pressing force of the lubricant supplying means (for example, the amount of bite of the brush roller into the photosensitive member, etc.). Also, the lubricant abundance ratio B can be controlled by the pressing force of the lubricant removing member (for example, the amount of bite of the brush roller into the photosensitive member) and the planting density of the brush fibers of the lubricant removing member.

The intermediate transfer member 131 is wound around a plurality of rollers 137A, 137B, 137C, and 137D and rotatably supported.
A cleaning unit 135 for removing toner remaining on the intermediate transfer member 131 is arranged on the intermediate transfer member 131 .

In this image forming apparatus 100, the photoreceptor 111Y, developing means 117Y, cleaning means 119Y, lubricant removing means 114Y, lubricant supplying means 116Y, etc. are integrally connected, and a process cartridge (image forming apparatus) detachably attached to the apparatus main body. forming unit). Alternatively, one or more members selected from the group consisting of charging means 113Y, exposure means 115Y, development means 117Y, lubricant removal means 114Y, lubricant supply means 116Y, primary transfer roller 133Y, and cleaning means 119Y are integrated with the photoreceptor 111Y. It may also be a process cartridge (image forming unit) that is configured in the same manner.

The process cartridge 200 has a housing 201, a photoreceptor 111Y housed therein, a charging means 113Y, a developing means 117Y, a lubricant supplying means 116Y, a cleaning means 119Y and a lubricant removing means 114Y, and a primary transfer roller 133Y. Further, the apparatus main body is provided with support rails 203L and 203R as means for guiding the process cartridge 200 into the apparatus main body. As a result, the process cartridge 200 can be attached to and detached from the apparatus main body. These process cartridges 200 can be a single image forming unit detachably attached to the main body of the apparatus.

The paper feed transport means 150 is provided so as to be able to transport the transfer material P in the paper feed cassette 211 to the secondary transfer roller 217 via a plurality of intermediate rollers 213A, 213B, 213C, and 213D and the registration roller 215 .

A fixing unit 170 fixes the color image transferred by the secondary transfer roller 217 . The paper discharge rollers 219 are provided so as to be able to be placed on the paper discharge tray 221 while sandwiching the transfer material P that has undergone the fixing process.

In the image forming apparatus 100 configured as described above, toner images are formed by the image forming units 110Y, 110M, 110C, and 110Bk. Specifically, first, the lubricant is supplied to the surfaces of the photosensitive members 111Y, 111M, 111C, and 111Bk by the lubricant supply means 116Y, 116M, 116C, and 116Bk. After that, the surfaces of the photosensitive members 111Y, 111M, 111C and 111Bk are discharged to be negatively charged by the charging means 113Y, 113M, 113C and 113Bk. Next, exposure units 115Y, 115M, 115C, and 115Bk expose the surfaces of the photoreceptors 111Y, 111M, 111C, and 111Bk based on image signals to form electrostatic latent images. Next, developing means 117Y, 117M, 117C and 117Bk apply toner to the surfaces of the photoreceptors 111Y, 111M, 111C and 111Bk to form toner images.

Next, primary transfer rollers (primary transfer means) 133Y, 133M, 133C, and 133Bk are brought into contact with the rotating intermediate transfer body 131 . As a result, the toner images of respective colors formed on the photoreceptors 111Y, 111M, 111C, and 111Bk are sequentially transferred onto the rotating intermediate transfer member 131 to transfer (primary transfer) a color image. During the image forming process, the primary transfer roller 133Bk is always in contact with the photoreceptor 111Bk. On the other hand, the other primary transfer rollers 133Y, 133M and 133C are in contact with the corresponding photoreceptors 111Y, 111M and 111C only during color image formation.

After the primary transfer rollers 133Y, 133M, 133C and 133Bk are separated from the intermediate transfer member 131, the toner remaining on the surfaces of the photosensitive members 111Y, 111M, 111C and 111Bk is removed by cleaning means 119Y, 119M, 119C and 119Bk. to remove. Next, the lubricants on the surfaces of the photoreceptors 111Y, 111M, 111C and 111Bk are removed by lubricant removing means 114Y, 114M, 114C and 114Bk. After that, in preparation for the next image forming process, lubricant is supplied to the surfaces of the photoreceptors 111Y, 111M, 111C, and 111Bk by lubricant supply means 116Y, 116M, 116C, and 116Bk, and if necessary, the photoreceptors 111Y, 111M, and 111C are supplied with lubricant. , 111Bk are neutralized by a neutralizing means (not shown), and then negatively charged by charging means 113Y, 113M, 113C, and 113Bk. As described above, in the image forming apparatus 100, the lubricant having a history of charging is removed from the surface of the photoreceptor 111 after the toner is removed, and then a new lubricant is supplied before being charged, in each image forming process. is configured as follows.

On the other hand, a transfer material P (for example, a support for carrying a final image, such as plain paper or a transparent sheet) accommodated in a paper feed cassette 211 is fed by a paper feed/conveyance means 150, and is fed by a plurality of intermediate rollers 213A and 213B. , 213 C, 213 D, and a registration roller 215 to a secondary transfer roller (secondary transfer means) 217 . Then, the secondary transfer roller 217 is brought into contact with the rotating intermediate transfer member 131 to collectively transfer the color image onto the transfer material P (secondary transfer). The secondary transfer roller 217 contacts the intermediate transfer member 131 only when secondary transfer is performed onto the transfer material P. As shown in FIG. After that, the transfer material P on which the color image has been collectively transferred is separated at a portion of the intermediate transfer member 131 having a high curvature.

After the transfer material P onto which the color image has been collectively transferred in this way is fixed by the fixing means 170, it is nipped by the paper discharge rollers 219 and placed on the paper discharge tray 221 outside the apparatus. Further, after separating the transfer material P on which the color image has been collectively transferred from the intermediate transfer body 131 , residual toner on the intermediate transfer body 131 is removed by the cleaning means 135 .

[toner]
The toner used in the image forming apparatus of the present invention is not particularly limited, but is composed of toner particles containing a binder resin and a colorant, and the toner particles may optionally contain other components such as a release agent. may be contained.
Toner particles constituting the toner preferably have a volume average particle diameter of 2 to 8 μm from the viewpoint of achieving high image quality.

The method for producing the above toner is not particularly limited, but known examples include a conventional pulverization method, a wet melting spheronization method in which the toner is prepared in a dispersion medium, a suspension polymerization method, a dispersion polymerization method, an emulsion polymerization aggregation method, and the like. and the like.

Inorganic fine particles such as silica and titania having an average particle diameter of about 10 to 300 nm and abrasives having an average particle diameter of about 0.2 to 3 μm can be externally added in appropriate amounts to the toner particles as external additives.

The toner can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
When the toner is used as a two-component developer, the carrier may be a conventionally known material such as a ferromagnetic metal such as iron, an alloy of ferromagnetic metal with aluminum or lead, or a compound of ferromagnetic metal such as ferrite and magnetite. can be used, and ferrite is particularly preferred.

Although the embodiments of the present invention have been specifically described above, the embodiments of the present invention are not limited to the above examples, and various modifications can be made.

The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. In the following examples, unless otherwise specified, operations were performed at room temperature (25°C). Moreover, unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass" respectively.

The number average primary particle size of various particles was measured as follows. First, a 10,000-fold enlarged photograph taken with a scanning electron microscope (manufactured by JEOL Ltd.) was loaded into a scanner. Next, from the obtained photographic image, 300 particle images excluding agglomerated particles were randomly analyzed using an automatic image processing analysis system Luzex (registered trademark) AP software Ver. 1.32 (manufactured by Nireco Co., Ltd.) was used to perform binarization processing, and the horizontal Feret diameter of each particle image was calculated. Then, the average value of the Feret diameters in the horizontal direction of each of the particle images was calculated as the number average primary particle diameter. At this time, the number average primary particle size of the metal oxide particles was measured for metal oxide particles that did not contain chemical species (coating layer) derived from the surface treatment agent.

[Synthesis Example 1: Preparation of composite particles (core-shell particles)]
(Composite particle 1)
Composite particles in which a coating layer (shell) of tin oxide (SnO ₂ ) was formed on the surface of a barium sulfate (BaSO ₄ ) core material (core) were produced using the production apparatus shown in FIG.

Specifically, 3500 cm ³ of pure water was put into the mother liquor tank 41, and then 900 g of spherical barium sulfate core material having a number average primary particle diameter of 80 nm was put in and circulated for 5 passes. The flow rate of the slurry flowing out from the mother liquor tank 41 was 2280 cm ³ /min. Moreover, the stirring speed of the strong dispersion device 43 was set to 16000 rpm. After completion of circulation, the slurry was diluted with pure water to a total volume of 9,000 cm ³ , and 1,600 g of sodium stannate and 2.3 cm ³ of sodium hydroxide aqueous solution (concentration: 25 N) were added and circulated for 5 passes. A mother liquor was thus obtained.

20% sulfuric acid was added to a homogenizer “magic LAB (registered trademark)” (manufactured by IKA Japan Co., Ltd.) as a strong dispersion device 43 while circulating the mother liquor so that the flow rate S2 flowing out from the mother liquor tank 41 was 200 cm ³ . supplied. The supply speed S3 was set to 9.2 cm ³ /min. The volume of the homogenizer was 20 cm ³ and the stirring speed was 16000 rpm. Circulation was carried out for 15 minutes, during which sulfuric acid was continuously fed to the homogenizer to obtain a slurry containing particles.

The resulting slurry was repulped and washed until its conductivity became 600 μS/cm or less, and then subjected to Nutsche filtration to obtain a cake. The cake was dried in air at 150° C. for 10 hours. The dried cake was then pulverized, and the pulverized powder was reduced and calcined at 450° C. for 45 minutes under a 1 vol % H ₂ /N ₂ atmosphere. In this way, composite particles 1 having a number average primary particle size of 100 nm, which consisted of a core of barium sulfate and a shell of tin oxide formed on the surface of the core, were produced.

Here, in the manufacturing apparatus shown in FIG. Reference numeral 41a indicates a stirring blade, reference numeral 43a indicates a stirring portion, reference numerals 41b and 43b indicate shafts, and reference numerals 41c and 43c indicate motors, respectively.

(Composite particle 2)
Composite particles 2 (number average primary particle size: 300 nm).

(Composite particle 3)
Composite particles 3 (number average primary particle size: 500 nm).

[Synthesis Example 2: Preparation of metal oxide particles (surface-treated particles) surface-treated with a surface-treating agent]
(Synthesis Example 2-1: Preparation of surface-treated particles 1)
5 g of untreated metal oxide particles of tin oxide (number average primary particle diameter: 50 nm) was added to 10 mL of methanol and dispersed at room temperature for 30 minutes using a US homogenizer. Then, 0.25 g of 3-methacryloxypropyltrimethoxysilane (“KBM-503”, manufactured by Shin-Etsu Chemical Co., Ltd.; formula S-15 below), which is a reactive surface treatment agent, and 10 mL of toluene are added, and the mixture is heated at room temperature for 60 minutes. Stirred. After removing the solvent with an evaporator, the mixture was heated at 120° C. for 60 minutes to obtain metal oxide particles having reactive functional groups.
S-15: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _OCH3 ) ₃

5 g of the metal oxide particles obtained above were added to 40 g of 2-butanol and dispersed using a US homogenizer at room temperature for 60 minutes. Next, 0.15 g of a surface treatment agent having a silicone chain on the side chain of the silicone main chain ("KF-9908", manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and further dispersed at room temperature for 60 minutes using a US homogenizer. did After dispersion, the solvent is evaporated at room temperature and dried at 120° C. for 60 minutes to obtain metal oxide particles surface-treated with a reactive surface treatment agent and a surface treatment agent having a silicone chain in the side chain (hereinafter , also referred to as surface-treated particles) 1 was produced.

(Synthesis Example 2-2: Production of surface-treated particles 2)
Surface-treated particles 2 were prepared in the same manner as in Synthesis Example 2-1, except that the composite particles 1 obtained above were used instead of tin oxide having a number average primary particle size of 100 nm.

(Synthesis Example 2-3: Production of surface-treated particles 3)
Surface-treated particles 3 were produced in the same manner as in Synthesis Example 2-1, except that the composite particles 2 obtained above were used instead of tin oxide having a number average primary particle size of 100 nm.

(Synthesis Example 2-4: Production of surface-treated particles 4)
Surface-treated particles 4 were prepared in the same manner as in Synthesis Example 2-1, except that the composite particles 3 obtained above were used instead of tin oxide having a number average primary particle size of 100 nm.

(Synthesis Example 2-5: Production of surface-treated particles 5)
In the same manner as in Synthesis Example 2-1, except that instead of tin oxide having a number average primary particle size of 100 nm, aluminum oxide (Al ₂ O ₃ ) having a number average primary particle size of 300 nm was used, the surface A treated particle 5 was produced.

(Synthesis Example 2-6: Production of surface-treated particles 6)
Surface-treated particles 6 were prepared in the same manner as in Synthesis Example 2-1, except that silica (SiO ₂ ) having a number average primary particle size of 100 nm was used instead of tin oxide having a number average primary particle size of 100 nm. was made.

(Synthesis Example 2-7: Production of surface-treated particles 7)
Instead of KF-9908, a surface treatment agent having a silicone main chain and not having a silicone chain in the side chain ("KF-9901", manufactured by Shin-Etsu Chemical Co., Ltd.) was used. Synthesis Example 2 Surface-treated particles 7 were produced in the same manner as in -3.

(Synthesis Example 2-8: Preparation of surface-treated particles 8)
Instead of KF-9908, Synthesis Example 2- Surface-treated particles 8 were produced in the same manner as in 3.

(Synthesis Example 2-9: Production of surface-treated particles 9)
Same as Synthesis Example 2-2, except that 3-methacryloxypropylmethyldimethoxysilane (“KBM-502”, manufactured by Shin-Etsu Chemical Co., Ltd.) (formula S-14 below) was used instead of KBM-503. Then, surface-treated particles 9 having reactive functional groups were produced.
S-14: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _CH3 )( _OCH3 ) ₂

(Synthesis Example 2-10: Production of surface-treated particles 10)
Same as Synthesis Example 2-2, except that 3-acryloxypropyltrimethoxysilane (“KBM-5103”, manufactured by Shin-Etsu Chemical Co., Ltd.) (formula S-7 below) was used instead of KBM-503. Then, surface-treated particles 10 having reactive functional groups were produced.
S-7: _CH2 =CHCOO( _CH2 ) _3Si ( _OCH3 ) ₃

(Synthesis Example 2-11: Production of surface-treated particles 11)
5 g of aluminum oxide (number average primary particle size: 300 nm) was added to 10 mL of 2-butanol, and dispersed at room temperature for 60 minutes using a US homogenizer. Then, 0.15 g of 3-methacryloxypropyltrimethoxysilane (“KBM-503”, manufactured by Shin-Etsu Chemical Co., Ltd.), which is a reactive surface treatment agent, is added, and further at room temperature for 60 minutes using a US homogenizer. distributed. After dispersion, the solvent was volatilized at room temperature and dried at 120° C. for 60 minutes to produce surface-treated particles 11 surface-treated with a reactive surface-treating agent.

The structures of the surface-treated particles 1 to 11 are summarized in Table 1 below.

[Preparation of Electrophotographic Photoreceptor]
(Example 1)
A. Preparation of Conductive Support A conductive support was prepared by cutting the surface of a cylindrical aluminum support.

B. Preparation of Intermediate Layer The following components were mixed in the following amounts and dispersed batchwise for 10 hours using a sand mill as a disperser to prepare a coating solution for forming an intermediate layer. The coating solution was applied to the surface of the conductive support by dip coating and dried at 110° C. for 20 minutes to form an intermediate layer having a thickness of 2 μm on the conductive support. X1010 (manufactured by Daicel-Evonik Co., Ltd.) was used as the polyamide resin, and SMT-500SAS (manufactured by Tayca Corporation, number average primary particle size: 0.035 μm) was used as the titanium oxide particles:
Polyamide resin 10 parts by mass Titanium oxide particles 11 parts by mass Ethanol 200 parts by mass.

C. Preparation of Charge Generating Layer The components below were mixed in the amounts shown below, and the mixture was heated to 0.5% with a circulation ultrasonic homogenizer (RUS-600TCVP, manufactured by Nippon Seiki Seisakusho Co., Ltd.) at 19.5 kHz and 600 W at a circulation flow rate of 40 L/hour. A coating liquid for forming a charge generation layer was prepared by dispersing for 5 hours. The resulting coating solution was applied to the surface of the intermediate layer by dip coating and air-dried to form a charge generation layer having a thickness of 0.3 μm on the intermediate layer. The charge-generating substances include titanyl phthalocyanine and (2R, A mixed crystal of 1:1 adduct of 3R)-2,3-butanediol and unadducted titanyl phthalocyanine was used. Also, S-LEC (registered trademark) BL-1 (manufactured by Sekisui Chemical Co., Ltd.) was used as the polyvinyl butyral resin. Also, as a mixed solvent, 3-methyl-2-butanone/cyclohexanone = 4/1 (volume ratio) was used:
Charge-generating substance 24 parts by mass Polyvinyl butyral resin 12 parts by mass Mixed solvent 400 parts by mass.

D. Preparation of charge transport layer A charge transport layer coating solution containing the following components in the following amounts was applied to the surface of the charge generation layer by dip coating and dried at 120°C for 70 minutes to obtain a charge layer having a thickness of 24 µm. A transport layer was formed on the charge generating layer. Iupilon (registered trademark) Z300 (manufactured by Mitsubishi Gas Chemical Company, Inc., bisphenol Z-type polycarbonate) was used as the polycarbonate resin. Also, as an antioxidant, IRGANOX (registered trademark) 1010 (manufactured by BASF Japan Ltd.) was used:
Charge transport material represented by the following chemical formula 2 60 parts by mass Polycarbonate resin 100 parts by mass THF (tetrahydrofuran) 800 parts by mass Toluene 200 parts by mass Antioxidant 4 parts by mass.

E. Formation of Protective Layer (Outermost Layer) A protective layer-forming coating solution (outermost layer-forming coating solution) obtained by mixing the following components in the following amounts was applied to the surface of the charge transport layer using a circular slide hopper applicator. The obtained film of the coating liquid is irradiated with ultraviolet rays (main wavelength: 365 nm) using a metal halide lamp for 1 minute (ultraviolet illuminance: 16 mW/cm ² , integrated light amount: 960 mJ/cm ² ) to cure the film. Thus, a protective layer having a thickness of 3.0 μm was formed on the charge transport layer. Photoreceptor 1 was thus produced. The polymerization initiator used was IRGACURE (registered trademark) 819 (manufactured by BASF Japan Ltd.):
Polymerizable monomer (compound represented by the following chemical formula M2) 120 parts by mass Surface treated particles 1 100 parts by mass Polymerization initiator 10 parts by mass 2-butanol 400 parts by mass THF 100 parts by mass Charge transport material 30 parts by mass.

式中のＲ’は、メタクリロイル基（ＣＨ_２＝Ｃ（ＣＨ_３）ＣＯ－）を表す。

R' in the formula represents a methacryloyl group (CH ₂ =C(CH ₃ )CO-).

(Examples 2-9, 12-14, Comparative Examples 1-2)
Photoreceptors 2 to 9, 12 to 14, and comparative photoreceptors 1 to 2 were produced in the same manner as in Example 1, except that the types of surface-treated particles were changed as shown in Table 1 below.

(Examples 10 and 11)
Photoreceptors 10 and 11 were produced in the same manner as in Example 2, except that the types of polymerizable monomers were changed to compounds represented by the following chemical formulas M1 and M3, respectively.

式中のＲは、アクリロイル基（ＣＨ_２＝ＣＨＣＯ－）を表す。

R in the formula represents an acryloyl group (CH ₂ =CHCO-).

(Comparative Example 3)
As the metal oxide particles, non-surface-treated aluminum oxide (Al ₂ O ₃ ) particles having a number average primary particle size of 300 nm are used, and a dispersant (BYK-P105, manufactured by Big Chemie Japan Co., Ltd.) is used. Thus, a comparative photoreceptor 3 was produced. Specifically, coating and curing were performed in the same manner as in Example 1, except that a coating solution for forming a protective layer in which the following components were mixed in the following amounts was used.
Polymerizable monomer (compound represented by the following chemical formula M2) 120 parts by mass Surface treated particles 11 100 parts by mass Dispersant (BYK-P105) 3 parts by mass Polymerization initiator 10 parts by mass 2-butanol 400 parts by mass THF 100 parts by mass Charge Transport substance 30 parts by mass.

(Comparative Example 4)
A comparative photoreceptor 4 was produced by changing the type of the surface-treated particles as shown in Table 1 below and by changing the polymerizable monomer to a polycarbonate resin (Iupilon Z300, manufactured by Mitsubishi Gas Chemical Company, Inc.). Specifically, a coating solution for forming a protective layer (coating solution for forming an outermost layer) obtained by mixing the following components in the following amounts was applied to the surface of the charge transport layer using a circular slide hopper applicator and heated at 120°C. By drying for 70 minutes, a protective layer having a thickness of 3.0 μm was formed on the charge transport layer.
Charge-transporting material represented by Chemical Formula 2 60 parts by mass Polycarbonate resin 100 parts by mass THF (tetrahydrofuran) 1600 parts by mass Toluene 400 parts by mass Antioxidant 4 parts by mass.

[Evaluation method]
The charging means of a full-color printer (bizhub PRESS C1070; Konica Minolta Co., Ltd., "bizhub" is a registered trademark of the same company) was modified to a charging roller system, and the photoreceptor of the above example or comparative example was mounted as a photoreceptor. An image forming apparatus was prepared.

As the lubricant stock provided in the lubricant supplying means, 80% by mass of fatty acid metal salt (zinc stearate) and 20% by mass of boron nitride were homogeneously mixed and molded. Used in Examples 3 to 5, and used in Example 7 was molded by uniformly mixing 80% by mass of fatty acid metal salt (zinc stearate) and 10% by mass of boron nitride. Moreover, in Comparative Examples 1 and 2, only fatty acid metal salt (zinc stearate) was molded.

An image was formed using each image forming apparatus, and its performance was evaluated.

(lubricant memory)
At 20°C and 50% RH, after printing 5,000 sheets of cyan solid vertical band images with coverage of 50% in A4 landscape orientation, a full half image was output, and the density difference between the band and non-band portions (lubricant memory ) occurred.
A: No density difference (no practical problem)
B: Very slight difference in concentration (no practical problem)
C: Density difference (no practical problem)
D: Density difference exists (practical problem)
E: There is a clear density difference (practical problem)

(Cleanability)
A durability test was conducted in which a solid cyan vertical band image with a coverage of 50% was continuously printed on 300,000 A4 sheets in a horizontal feed direction in a low temperature and low humidity environment (LL environment) of 10° C. and 15% RH. Cleanability was evaluated before and after the durability test.
Specifically, using the photoreceptor and cleaning blade before and after the durability test, 5,000 cyan solid vertical band images with 50% coverage in a low temperature and low humidity environment (temperature of 10° C., humidity of 15% RH) were printed in the direction of A4 vertical feed. After continuous printing, a full-surface half image was output. After that, the photoreceptor and the image were visually observed and evaluated according to the following criteria.
A: No residue left on front surface (practically no problem)
B: Chipping or filming occurred, but no effect on the image (no practical problem)
C: Unwiped or filming occurred only at the blade chipping portion, but the effect on the image was slight (practically no problem)
D: Influences such as unwiped or filming occurred in the image only at the blade chipping portion (practical problem)
E: The entire surface was left unwiped or filming occurred, and the image was also affected (problematic in practice).

(wear resistance)
A durability test was carried out in which 300,000 sheets of A4 paper were continuously printed with a cyan solid vertical band image having a coverage of 50% in a low temperature and low humidity environment (LL environment) of 10° C. and 15% RH. The wear resistance of the photoreceptor was evaluated by measuring the amount of loss in film thickness of the outermost layer of the photoreceptor before and after the durability test.

The amount of film thickness loss was calculated by the following method.
The film thickness of the outermost layer of the photoreceptor was obtained by randomly measuring 10 uniform film thickness portions (film thickness profile was prepared and excluding film thickness variation portions at the leading end and trailing end of coating) and averaging the results. The value was taken as the film thickness of the outermost layer. An eddy current type film thickness measuring device "EDDY560C" (manufactured by HELMUT FISCHER GMBTE CO) was used as the film thickness measuring instrument, and the difference in the film thickness of the outermost layer before and after the durability test was calculated as the amount of film thickness loss (μm). , and the amount of wear was evaluated according to the following criteria.
A: 1.0 μm or less (no practical problem)
B: More than 1.0 μm and 2.0 μm or less (no practical problem)
C: more than 2.0 μm and 3.0 μm or less (no practical problem)
D: more than 3.0 μm and 4.0 μm or less (practical problem)
E: more than 4.0 μm (problematic in practice)

The evaluation results are shown in Table 1 below.

As is clear from Table 1 above, the outermost layer of the photoreceptor is a polymerized cured product of a resin composition containing a polymerizable monomer and at least one metal oxide particle surface-treated with a surface treatment agent, In addition, when an image is formed by the image forming apparatus of Examples 1 to 14, in which the lubricant contains a fatty acid metal salt and boron nitride, the occurrence of lubricant memory is suppressed, the cleanability is good, and the wear resistance of the photoreceptor is improved. was also good. In particular, Example 3, in which the main chain and side chains of the surface treatment agent are silicone species, has excellent cleaning properties compared to Examples 8 and 9, in which only the main chain or only the side chains of the surface treatment agent are silicone species. was In addition, the image forming apparatus of Example 14, in which a photoreceptor containing metal oxide particles treated without using a surface treatment agent having a silicone chain and a lubricant containing a fatty acid metal salt and boron nitride are combined, is practicable. However, the evaluation results were lower than those of other examples.

On the other hand, the outermost layer of the photoreceptor is a polymerized cured product of a resin composition containing a polymerizable monomer and at least one metal oxide particle surface-treated with a surface treatment agent, but the lubricant is only a fatty acid metal salt. When an image was formed by the image forming apparatus of Comparative Example 1, lubricant memory occurred and the density difference of the image was large. In addition, when an image was formed by the image forming apparatus of Comparative Example 2 in which a lubricant consisting only of a fatty acid metal salt was used, the cleanability was very low in both cases.

Furthermore, when an image was formed by the image forming apparatus of Comparative Example 3 using a photoreceptor containing metal oxide particles that were not subjected to any surface treatment, lubricant memory, cleanability, and wear resistance of the photoreceptor were all poor. Further, the image forming apparatus of Comparative Example 4, in which the outermost layer of the photoreceptor is a cured polymer of a resin composition containing a polymer and at least one metal oxide particle surface-treated with a surface treatment agent, was used to form an image. Once formed, the abrasion resistance of the photoreceptor was very poor.

According to the image forming apparatus of the present invention, it is possible to form images while maintaining cleanability over a long period of time and suppressing the occurrence of lubricant memory. Therefore, the present invention is expected to expand the range of application of electrophotographic image forming apparatuses and contribute to the development and spread of technology in the same field.

11 Charging roller 11a Core metal 11b Elastic layer 11c Resistance control layer 11d Surface layer 11e Pressure spring 20 Case 21 Brush roller 22 Lubricant stock 23 Pressure spring 30 Blade member 31 Support member 41 Mother liquid tank 41a Stirring blades 41b, 43b Shaft 41c, 43c motors 42, 44 circulation pipe 43 strong dispersion device 43a stirring units 45, 46 pump 100 image forming apparatuses 110Y, 110M, 110C, 110Bk image forming units 111Y, 111M, 111C, 111Bk photoconductors 113Y, 113M, 113C, 113Bk charging means 114Y, 114M, 114C, 114Bk Lubricant removal means 115Y, 115M, 115C, 115Bk Exposure means 116Y, 116M, 116C, 116Bk Lubricant supply means 117Y, 117M, 117C, 117Bk Development means 118Y Leveling blades 119Y, 119M, 119C, 11 9Bk cleaning Means 131 Intermediate transfer bodies 133Y, 133M, 133C, 133Bk Primary transfer rollers (transfer means)
135 Cleaning Means 137A, 137B, 137C, 137D Roller 150 Paper Feed Conveyance Means 170 Fixing Means 200 Process Cartridge 201 Case 203R, 203L Support Rail 211 Paper Feed Cassette 213A, 213B, 213C, 213D Intermediate Roller 215 Registration Roller 217 Secondary Transfer Roller (transfer means)
219 Paper discharge roller 221 Paper discharge tray A Portion B where lubricant abundance ratio A was measured Portion P where lubricant abundance ratio B was measured Transfer material SC Document image reader S1 Power source S2 Flow speed S3 Supply speed

Claims (9)

a photoreceptor having a protective layer as the outermost layer;
charging means for charging the surface of the photoreceptor;
an exposure means for exposing the photosensitive member charged by the charging means;
a developing means for supplying toner to the photosensitive member exposed by the exposing means to form a toner image;
a transfer means for transferring the toner image formed on the photoreceptor;
cleaning means for removing toner remaining on the surface of the photoreceptor;
An image forming apparatus comprising a lubricant applying unit for applying a lubricant to the surface of the photoreceptor,
The outermost layer of the photoreceptor contains a polymerized cured product of a resin composition containing a polymerizable monomer and at least one kind of metal oxide particles, and at least one kind of the metal oxide particles contains silicone in a side chain. surface-treated with a surface-treating agent having chains ,
An image forming apparatus, wherein the lubricant contains a fatty acid metal salt and boron nitride. 2. The image forming apparatus according to claim 1 , wherein the surface treatment agent having a silicone chain in its side chain is a surface treatment agent having a poly(meth)acrylate main chain or a silicone main chain. 3. The metal oxide particles according to claim 1 , wherein the metal oxide particles are at least one selected from the group consisting of composite particles having barium sulfate as a core material and being coated with tin oxide, alumina particles, tin oxide particles, and silica particles. image forming device. 4. The image forming apparatus according to claim 1, wherein the metal oxide particles have a number average primary particle diameter of 50 nm or more and 500 nm or less. The image forming apparatus according to any one of claims 1 to 4 , wherein the metal oxide particles have reactive functional groups. The image forming apparatus according to any one of claims 1 to 5 , wherein the fatty acid metal salt is zinc stearate. The content ratio of the boron nitride in the lubricant is in the range of Mb/Ma from 50/50 to 1/99, where Ma is the mass of the fatty acid metal salt and Mb is the mass of the boron nitride. 7. The image forming apparatus according to any one of 1 to 6 . 8. The presence ratio of the lubricant per unit area of the surface of the photoreceptor after application of the lubricant by the lubricant application unit and before charging by the charging unit is 1 atm % or more. 10. The image forming apparatus according to claim 1. The image forming apparatus according to any one of claims 1 to 8 , wherein the charging means is proximity charging means.

Images