JPH09204055A - Polysilane mixture, electrophotographic photoreceptor and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polysilane mixture suitable for use as a material for the carrier transferring layer of an electrophotographic photoreceptor. SOLUTION: This polysilane mixture consists of a polysilane compd. and a binder produced by polymerizing an anionic-polymerizable monomer in the presence of the polysilane compd. This photoreceptor has a photosensitive layer 2 formed by laminating an optical carrier exciting layer 3 and a carrier transferring layer 4 contg. the polysilane mixture on the electrically conductive substrate 1. This photoreceptor is fit for an image forming device adopting a rear exposure-development system and an external electrostatic latent image system, ensures high performance and high reliability for the device and reduces the size of the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilane mixture having enhanced film strength while maintaining the excellent properties of polysilane compounds, an electrophotographic photosensitive member using the polysilane mixture in a carrier transport layer, and an electrophotographic photosensitive member. The present invention relates to an image forming apparatus using a body.

[0002]

2. Description of the Related Art Polymer materials such as poly-N-vinylcarbazole (PVK) have been used as a material for a carrier transport layer of an electrophotographic photosensitive member, but recently, there has been a demand for improving carrier mobility. In order to comply, a low molecular weight resin-dispersed composite material in which a low molecular weight compound such as an arylamine derivative or a hydrazone derivative is dispersed in an inert polymer binder such as a polycarbonate resin has been proposed.

However, the recent demand for high carrier mobility in materials for carrier transport layers is not yet satisfactory, and higher carrier mobility is required especially for holes.

In response to such a demand, it has been proposed to employ a polysilane compound having a high carrier mobility as a material for a carrier transport layer of an electrophotographic photosensitive member. For example, according to JP-A-2-133416, polysilane is used. A hole-transporting substance comprising a block copolymer of a polymerizable block A and a block B of a polymer of an anionically polymerizable monomer, and according to JP-A-2-294654, a light-receiving layer containing a polysilane compound. Have been proposed respectively.

According to Japanese Patent Application No. 6-90138, when polysilane is used alone as a material for a carrier transport layer, the polysilane compound has a weight average molecular weight of 50,000.
It is also proposed that a hole mobility of 10 ⁻⁵ cm ² / V · sec or more, which is ˜2,500,000 and a ratio of 10 or less compared to the number average molecular weight, is suitable.

On the other hand, the Wurtz coupling reaction, which is the most general and practical method for synthesizing these polysilane compounds, has the problems that it is difficult to control the molecular weight, exhibits a polymodal molecular weight distribution, and has a low yield. .
Therefore, it is difficult to provide a large amount of a polysilane compound having a high molecular weight and a narrow molecular weight distribution at a low cost by the Wurtz coupling reaction method.

To address this, for example, a method of mixing polysilane with a polymer resin (see Japanese Patent Laid-Open No. 4-178652, etc.), a method of mixing polysilane with an organic low molecular carrier transporting agent and a polymer resin ( See JP-A-3-170940, JP-A-4-151669, and Japanese Patent Application No. 6-90138), and a method of forming a copolymer of polysilane and another polymer (JP-A-2-13).
3416, JP-A-2-153359, etc.) are proposed.

[0008]

However, even with the polysilane compounds proposed above, the compatibility between the polysilane and the polymer resin is very poor, and there is a problem that a uniform mixed film cannot be obtained.

Further, even with the above-mentioned proposed methods for synthesizing polysilane compounds, it is not possible to obtain a good compatibility by simple mixing. There are problems that the high mobility of a certain hole is lost and it is technically difficult to stably obtain the desired polysilane compound.

The present invention has been completed as a result of intensive research conducted by the present inventor in view of the above circumstances, and an object thereof is not to impair the excellent property of a polysilane compound that has a high carrier transporting ability and to provide a mechanical property. An object of the present invention is to provide a polysilane mixture suitable for a material for a carrier transport layer of an electrophotographic photoreceptor, which has excellent film properties such as high mechanical strength, high transparency, and good adhesion.

Another object of the present invention is to provide an electrophotographic photoreceptor using the above polysilane mixture, which has high carrier mobility and excellent characteristics such as mechanical strength and durability.

Still another object of the present invention is to provide an image forming apparatus using the above electrophotographic photosensitive member, which has high performance and high reliability and can be further downsized.

[0013]

The polysilane mixture according to claim 1 of the present invention comprises a polysilane compound represented by the following chemical formula 1 and the following (A) in the presence of the polysilane compound.
And a binder produced by polymerizing an anionic polymerizable monomer selected from the above.

[0014]

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(A) α-methylstyrene, butadiene,
Styrene, methacrylic acid ester, acrylic acid ester, acrylonitrile, nitrostyrene, ethyl α-cyanoacrylate, vinylidene cyanide The electrophotographic photoreceptor according to claim 2 of the present invention has a photocarrier excitation layer on a conductive substrate. And a carrier transport layer containing the polysilane mixture according to claim 1 are laminated to form a photosensitive layer.

The electrophotographic photoreceptor according to claim 3 of the present invention has a photosensitive layer comprising a carrier transporting material comprising the polysilane mixture according to claim 1 and a photocarrier excitation material on a conductive substrate. It is characterized by being formed.

An image forming apparatus according to a fourth aspect of the present invention is the electrophotographic photoreceptor according to the second aspect, wherein the conductive substrate is translucent, and the electrophotographic photoreceptor is provided on the side of the photosensitive layer. The developing means is provided and exposing means for irradiating the image exposing light from the side of the conductive substrate, and between the developing means and the conductive substrate for forming a toner image on the surface of the electrophotographic photosensitive member. The image exposing light is emitted from the exposing means while applying a voltage to.

Further, an image forming apparatus according to a fifth aspect of the present invention comprises an electrophotographic photosensitive member according to the second aspect, a charging unit for applying an electric charge to the surface of the electrophotographic photosensitive member, and an electrophotographic photosensitive member. And a toner corresponding to the electrostatic latent image as well as forming an electrostatic latent image on the surface of the electrophotographic photosensitive member by the charging means and the exposing means. Developing means for forming an image on the surface of the electrophotographic photosensitive member, transfer means for transferring the toner image to the transfer material, and removing residual toner on the surface of the electrophotographic photosensitive material after transferring the toner image to the transfer material. It is characterized in that cleaning means and charge removing means for removing the residual electrostatic latent image after the transfer are arranged.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A polysilane mixture according to claim 1 of the present invention is prepared by polymerizing an anionic polymerizable monomer selected from the above (A) in a system in which a polysilane compound represented by the above chemical formula 1 is present. It is produced by making a binder. Since the polysilane compound used in the present invention does not need to limit the molecular weight and the molecular weight distribution, it can be provided in a large amount and at a low cost even in a general synthetic method. Then, by polymerizing the anion-polymerizable monomer in the presence of the polysilane compound, the polysilane compound and the polymer of the anion-polymerizable monomer are compatible at the molecular level. An excellent polysilane-based carrier transport layer material can be obtained. Here, the amount of the polymer produced by anionic polymerization is 20 to 80% by weight of the entire polysilane mixture, because the photoreceptor characteristics are good, and the economy is also good. Is most suitable when considering.

(Structure of Polysilane Compound) R _{1 to} R ₆ of the polysilane compound represented by the above chemical formula ₁ are, in addition to hydrogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxy group and a substituted group. There is an alkoxy group. Examples of the alkyl group, aryl group and alkoxy group include methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, nonyl, decyl, pentadecyl, stearyl, cyclohexyl, phenyl, tolyl, xylyl, naphthyl, methoxy and ethoxy. Can be mentioned. Further, these substituents include alkyl, aryl, halogen, nitro, amino, alkoxy, cyano and the like.

The polysilane compound used in the present invention is
As shown in, x, y, and z are indicated by 0 or 1 to indicate the presence or absence of each unit. For example, if x = y = 1 and z = 0, the composition is such that two types of units are alternately and continuously arranged.

Further, the polysilane compound used in the present invention may be a copolymer of the polysilane compound of Chemical formula 1 as shown in Chemical formula 2 below. According to Formula 2, x,
It is possible to selectively set y, z, x ′, y ′, and z ′ to 0 or 1, and to combine various combinations depending on the presence or absence of each unit. That is, a compound of a polymer composed of monomers of three kinds of units and a polymer composed of monomers of three kinds of units, a compound of a polymer composed of monomers of three kinds of units and a polymer composed of monomers of two kinds of units, and three kinds , A compound of a polymer composed of a monomer of one unit and a polymer of a monomer of one kind of unit, a compound of a polymer of a monomer of two kinds of unit and a polymer of a monomer of two kinds of unit, a monomer of two kinds of unit There is a compound of a polymer consisting of the above and a polymer consisting of a monomer of one type unit, a polymer consisting of a monomer of one type unit and a polymer consisting of a monomer of one type unit. In addition, there are compounds that are combinations of these compounds.

[0023]

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(Production of Polysilane Mixture) The polysilane compound represented by the above Chemical Formula 1 or Chemical Formula 2 and the anionic polymerizable monomer selected from the above (A) are mixed in an organic solvent, and the reaction temperature is -80 to + 50 ° C. Polymerization of the monomer is carried out below. In the polymerization, light irradiation or an initiator may be added to accelerate the polymerization reaction. The polymerization reaction is completed within 1 to 5 hours, and as a result, a polysilane mixture composed of an anion-polymerized polymer (molecular weight: 5,000 to 100,000) and a polysilane compound is obtained.

(Structure of Electrophotographic Photosensitive Member) FIG. 1 is a sectional view showing a basic layer structure of an electrophotographic photosensitive member according to claim 2 of the present invention. FIG. 1 shows an example in which a laminated type photosensitive layer 2 is formed on a conductive substrate 1. The photosensitive layer 2 comprises a photocarrier excitation layer 3 and a carrier transport layer 4 made of a polysilane mixture. These layers 3 and 4 may be changed in the stacking order.

FIG. 2 is a sectional view showing the basic layer structure of an electrophotographic photosensitive member according to claim 3 of the present invention. FIG.
Is an example in which a single photosensitive layer 7 containing, for example, a granular photocarrier excitation material 6 in a carrier transport material 5 made of a polysilane mixture is formed on a conductive substrate 1.

The conductive substrate 1 is made of aluminum (A
1), SUS, copper (Cu), brass, nickel (Ni), or other metal conductors, or glass, ceramics, or other insulators whose surface is coated with a conductive thin film. Further, as the translucent conductive substrate 1, translucent glass,
Tin oxide (SnO ₂ ) and indium tin oxide (Indium tin oxide) are used on the surface of supports such as quartz, sapphire, and ceramics.
A transparent conductive layer such as Tin Oxide (ITO) or an organic conductive material coated by vapor deposition and subjected to a conductive treatment is used.

Although the conductive substrate 1 is generally in the form of a drum, it may be in the form of a sheet, a belt or a web-like flexible conductive sheet.
l, Ni or other metal sheet or polyester, nylon, polyimide or other polymer resin film on top of A
A metal, such as 1, Ni, or a transparent conductive material such as SnO ₂ or ITO, or an organic conductive material coated by vapor deposition or the like and subjected to a conductive treatment is used.

As a constituent material of the photocarrier excitation layer 3 and the photocarrier excitation material 6, an organic or inorganic photoconductive material known per se can be used. As the organic photoconductive material, for example, titanyl phthalocyanine, metal phthalocyanine pigments, metal-free phthalocyanines, perylene pigments, polycyclic quinone pigments, squarylium dyes, azurenium dyes, thiapyrylium dyes, high carrier generation efficiency using trisazo pigments, etc. The organic photo-semiconductor having is selected. Examples of the inorganic photoconductive material include amorphous Se, SeAs, SeTe, or Si (a-Se, a-).
SeAs, a-SeTe, a-Si), CdS, ZnO
Etc. Further, as a method for forming the photocarrier excitation layer 3, a vacuum vapor deposition method, an active reaction vapor deposition method, an ion plating method, an RF sputtering method, a DC sputtering method, an RF magnetron sputtering method, a DC magnetron sputtering method, a thermal CVD method, There is a plasma CVD method or the like.

When the photocarrier excitation layer 3 is formed of a-Si, carbon (C), nitrogen (N), oxygen (O) and germanium (Ge) are added to the photocarrier excitation layer 3 to amorphize SiC and SiN. , SiO, or SiGe layer may be used. Further, by forming a layer containing an element such as boron (B) or phosphorus (P), which is an impurity element for controlling the conductivity type, a function such as a carrier injection blocking layer can be provided.

Further, the photocarrier excitation material 6 of the photosensitive layer 7
When an a-Si-based powder is used as the
It can be produced similarly to the Si-based photocarrier excitation layer 3. The shape may be columnar, spherical, or flake-shaped, in addition to the granular shape. The diameter may be 0.05 to 5 μm, preferably 0.1 to 3 μm. 1-80 of the powder in the photocarrier excitation layer 3
The content of the carrier transporting material 5 is preferably in the range of 5% by weight, preferably 5 to 60% by weight, and the content thereof is dispersed in the carrier transport material 5 by a stirring method, an ultrasonic dispersion method or the like.

In addition, titanyl phthalocyanine (hereinafter,
The photosensitive layer 7 may be a dispersion of (abbreviated as TiOPc) in a polysilane compound, which can provide high sensitivity to image exposure particularly on the long wavelength side. This TiOPc is obtained by subjecting the raw material TiOPc pigment to a purification treatment such as sublimation purification or purification with an acid or an alkali together with a grinding aid or a solvent, or by collecting it in the form of fine particles by a vapor deposition method. The prepared product is kneaded together with various solvents using various dispersers and dispersed in the polysilane compound. Here, the content of TiOPc in the photosensitive layer 7 may be 1 to 80% by weight, preferably 10 to 60% by weight.

The electrophotographic photosensitive member according to claim 2 or 3 of the present invention is further improved or changed in accordance with the required electrophotographic characteristics based on the above basic layer structure. Good. For example, by providing an intermediate layer between the conductive substrate 1 and the photosensitive layers 2 and 7 thereon, the chargeability can be increased and the residual potential can be reduced. Alternatively, a surface layer may be provided on the photosensitive layers 2 and 7 to enhance the charging property and the durability.

(Formation of Carrier Transport Layer by Polysilane Mixture) The carrier transport layer 4 containing the polysilane mixture according to claim 1 of the present invention or the photosensitive layer 7 made of the polysilane mixture can be prepared by various known methods. Can be formed. For example, the polysilane mixture is made into a solution with an organic solvent, which is then subjected to bar coating, dipping,
It is formed by coating and drying by a coating method such as a melt extrusion method or a spray method. This organic solvent includes aromatic hydrocarbons such as benzene and toluene, alcohols such as methyl alcohol, ethyl alcohol and IPA (isopropyl alcohol), ethers such as tetrahydrofuran and dimethyl ether, ketones such as acetone and methyl ethyl ketone, and esters. The halogens, halogenated hydrocarbons and the like are used alone or in combination of two or more.

Since the polysilane mixture of the present invention is mixed with a polymer resin in addition to the polysilane compound, there is no limitation on the molecular weight and the molecular weight distribution conventionally required for polysilane. It can be supplied at low cost.

(Type of image forming apparatus) Claim 2 of the present invention
Alternatively, the image forming apparatus having the electrophotographic photosensitive member according to the third aspect employs an electrophotographic system in which an electrostatic latent image is formed on the surface of the photosensitive member by charging or voltage application and exposure. The image forming apparatus according to claim 4 is based on a so-called backside exposure simultaneous development system, and the image forming apparatus according to claim 5 is a Carlson method or a capacitive image method (NP method, K method).
This is based on a so-called external charge latent image method such as the IP method). According to the image forming apparatus of the present invention, the electrophotographic photosensitive member mounted on them can form a photosensitive layer having high carrier mobility by the polysilane mixture of the present invention, whereby the photocarriers excited inside the photosensitive layer are high. It becomes possible to move inside the photosensitive layer at high speed, and the time until the electrostatic latent image is formed is shortened. As a result, the rotation speed of the drum-shaped photosensitive member can be increased and high-speed image formation can be performed. You can Moreover, since the photocarriers excited inside the photosensitive layer immediately contribute to static elimination even in the static elimination due to the exposure after the transfer, the area of the photosensitive layer required for the static elimination can be narrowed, which is coupled with the speedup of the photosensitive drum. The diameter of the drum-shaped photosensitive member can be reduced, and the image forming apparatus can be downsized.

Any of these image forming apparatuses can be configured as a copying machine or a printer. Here, the copier has a structure for exposing the photosensitive layer of the electrophotographic photosensitive member to the light reflected from the original by using an optical system such as a lens and a mirror, and the printer is a laser controlled by an electric signal. Or a light emitting light source such as an LED array, a liquid crystal shutter array, or an EL array is used to expose the photosensitive layer of the electrophotographic photosensitive member.

(Image forming apparatus of rear exposure simultaneous development system)
Next, the image forming apparatus of the back exposure simultaneous development system according to claim 4 of the present invention will be specifically described in detail.

FIG. 3 is a schematic view showing an image forming section 8 of a back exposure simultaneous development type image forming apparatus according to claim 4 of the present invention. This is an electrophotographic system in which corona charging is unnecessary and exposure and development can be performed almost at the same time. In the figure, 9 is a light-transmitting substrate in which a light-transmitting conductive layer is coated on the light-transmitting conductive layer. Is a drum-shaped electrophotographic photosensitive member including a conductive conductive substrate 10 and a photosensitive layer 13 laminated thereon, and the photosensitive layer 13 includes a photocarrier excitation layer 11 and a carrier transport layer 12.
An example of stacking is shown. 14 is LE as an exposure means
The D array head, 15 is a developing machine as a developing means, and 16 is a transfer roller as a transfer means. LED array head
The developing device 15 and the developing device 15 are arranged substantially symmetrically with a part of the photoconductor 9 interposed therebetween. Such an LED array head 14 is a compact L type dynamic drive type L with low power consumption.
An ED array head is preferably used. Reference numeral 17 denotes an LED array as a light source for erase, which is a charge eliminating means, and may be arranged outside the photoconductor 9. Further, the LED array 17 is not always necessary.

The developing machine 15 comprises, for example, a columnar magnetic pole roller 18 having eight poles, a cylindrical conductive sleeve 19 arranged over the outer periphery thereof, and a toner receiver 20.
A one-component conductive magnetic toner or a two-component developer composed of a conductive magnetic carrier and an insulating toner, which is stored as a developer, is delivered to the outer periphery of the conductive sleeve 19 to form a magnetic brush 21.

A bias power source 22 is provided between the conductive sleeve 19 and the translucent conductive substrate 10.
・ Depending on the potential characteristics of the photoconductor 9 between 19 and + or-
A voltage of 500 V or less is applied.

Reference numeral 23 is a toner image formed on the surface of the photoconductor 9, 24 is a recording paper as a transfer material, and 25 is a residual toner after transfer. In addition to this, the rotation driving means of the developing machine 15 and the rotation means of the photoconductor 9 are provided. Although the LED array head is used here as the exposure means 14, it may be a laser, a liquid crystal shutter array, or an EL array head.

The erasing light source 17 as a charge eliminating means,
In addition to the LED array, a halogen lamp, a fluorescent lamp, a light source such as an EL array can be used.

Thus, according to the image forming apparatus 8 having the above-described structure, the LE from the light-transmissive conductive substrate 10 side of the rotating photoconductor 9 is LE.
When image exposure light is irradiated from the D array head 14 to generate holes and electrons as photocarriers inside the photocarrier excitation layer 11, if a negative bias voltage is applied to the developing device 15 side, the bias is applied. Holes are generated by the voltage and the carrier transport layer 12
Of the magnetic brush 21 and the negative charges at the end of the magnetic brush 21 to cancel each other, and toner adheres to the surface of the photoconductor 9 to form a toner image 23. Then, the toner is transferred onto the recording paper 24 by the transfer roller 16 and then fixed.

When the photocarrier excitation layer 11 and the carrier transport layer 12 made of a polysilane mixture are combined as the photosensitive layer 13, the carrier mobility of the carrier transport layer 12 is 10 ^−5.
It is as high as cm ² / Vt · sec or more and has excellent carrier transport characteristics. As a result, the photocarriers generated in the photocarrier excitation layer 11 are efficiently transferred to the surface of the carrier transport layer 12, so that a high image forming speed can be obtained.

Next, the specific contents of the image forming unit 8 having the above-mentioned structure will be described in more detail with reference to FIG.

FIG. 4 is a schematic view of the essential parts showing the developer pool 26 formed by the photoconductor 9 and the developing machine 15.

The developing machine 15 for holding the developer comprises a conductive sleeve 19 and a magnetic pole roller 18 disposed inside the conductive sleeve 19, and the developer is conveyed by fixing the magnetic pole roller 18 and rotating the sleeve 19. Or the sleeve 19 may be fixed and the magnetic pole roller 18 inside may be rotated.

Here, when the developer is conveyed in the direction opposite to that of the photoconductor 9, the friction between the two causes the conductive sleeve 19 of the developing device 15 and the photoconductor 9 to be located downstream of the closest position (the photoconductor 9 is the developer). A developer pool 26 is formed on the side of the developer. In other words, the portion that exceeds the original height of the developer is the developer pool.
26, the developer conveying speed for generating the developer pool 26, the height of the developer, the gap between the sleeve 19 and the surface of the photoconductor 9, and the like are the rotation speed of the photoconductor 9 and necessary. It is appropriately set according to the size of the developer pool 26.

Reference numeral 27 is a control electrode.
27 is provided on the conductive sleeve 19 at the closest position to the photoconductor 9, and is insulated from the conductive sleeve 19 by an insulator 28. Control electrode
A voltage is applied from the power supply 29 to the power source 27, which is formed in a strip shape along the lengthwise direction of the conductive sleeve 19 so that a uniform electric field is applied to the photoconductor 9 and the developer at that time. This control electrode 27
Are not indispensable and are adopted as appropriate.

As the developer, for example, a conductive magnetic toner is used, which may be a one-component developer as long as it forms the magnetic brush 21 and the developer reservoir 26 and has necessary conductivity. A carrier and an insulating toner may be mixed at a predetermined mixing ratio to obtain a required electric conductivity, and a two-component developer may be used.

Here, the position for image exposure is not the position A near the surface of the photoconductor 9 and the conductive sleeve 19, but the position of the developer pool 26 formed on the downstream side in the rotation direction of the photoconductor 9. B, and preferably in the downstream half of the developer pool 26. By performing the exposure at the position B of the developer pool 26, the photoreceptor 9 is sufficiently charged until the exposure, and the influence of the history of the potential of the photoreceptor 9 before the charging is suppressed, and the photoreceptor 9 is charged. Residual toner on the surface of 25
The toner on the image background portion is sufficiently collected. Further, since the photosensitive member 9 is sufficiently charged and then exposed to lose the electric charge, the electric attraction between the developer and the photosensitive member 9 is strong and a good toner image 23 is formed.

After the toner image 23 is formed, the photoconductor 9 is quickly separated from the developer pool 26, so that the toner image 23 on the surface of the photoconductor 9 is disturbed by mechanical force such as collision and friction of the developer. The toner image 23 having a good resolution can be obtained.

At the position of the developer pool 26, the distance between the surface of the photoconductor 9 and the magnetic pole roller 18 is larger than at the position A where the surface of the photoconductor 9 and the conductive sleeve 19 are closest to each other. Therefore, the magnetic force for attracting the developer to the magnetic pole roller 18 side is weak, and a part of the toner image 23 formed on the surface of the photoconductor 9 is collected by the magnetic force on the developing machine 15 side to lower the image density. Alternatively, it is possible to prevent the resolution from being deteriorated by being disturbed by the magnetic force.

Further, the strip-shaped control electrode 27 is grounded to a common potential with the transparent conductive substrate 1, or the sleeve 19 is used.
The potential is set lower or higher than the potential of.

When the control electrode 27 capable of applying a potential independently of the sleeve 19 is thus provided, the surface potential of the photoconductor 9 is neutralized via the developer, or the potential of the surface of the photoconductor 9 is made uniform. It is possible to cancel the influence of the history of the photoconductor 9 due to the charging and the presence or absence of the roller in the previous process. As a result, when repeatedly used, for example, when the photoconductor 9 is rotated several times to obtain one image, a stable development state and a recorded image can be obtained. Here, by adjusting the potential of the control electrode 27, it is possible to obtain the optimum image forming conditions by adjusting the image density, background fog, and the like. Further, by increasing the potential of the control electrode 27 and decreasing the potential of the conductive sleeve 19, it is possible to carry out so-called reversal development in which toner adheres to the non-exposed area and toner does not adhere to the exposed area.

The toner image 23 formed on the surface of the photoconductor 9 is then transferred onto the recording paper 24, fixed and becomes a recorded image, and the residual toner 25 left on the surface of the photoconductor 9 without being transferred.
Are collected by the developing machine 15 and reused in the next image forming process.

Furthermore, by erasing the charge-removing light from the erase light source 17 to the photoconductor 9 after transfer, the influence of the history of the photoconductor 9 due to the presence or absence of charging or exposure in the previous process can be more effectively canceled. Therefore, it is possible to suppress image problems such as an afterimage phenomenon during repeated use. Further, the charge trapped on the surface of the carrier transport layer 12 of the photoconductor 9 is erased, the electric attraction between the photoconductor 9 and the residual toner 25 on the surface is eliminated, and the residual toner 25 is collected in the developing machine 15. It can be easily done.

The carrier transport layer 12 is made up of the photoconductor 9
Good surface characteristics can be provided even when the surface layer also serves as the surface layer. That is, the layer of the polysilane mixture of the present invention has the features that the surface is hard and has appropriate slipperiness, it is excellent in abrasion resistance and printing durability, and the charging property is also good. It is also advantageous as a body surface layer.

(External Electrostatic Latent Image Type Image Forming Apparatus) Next, the external charge latent image type image forming apparatus according to claim 5 of the present invention will be described in detail by taking the Carlson method as an example.

FIG. 5 is a schematic view showing an image forming section 30 of an external charge latent image type image forming apparatus according to a fifth aspect of the present invention. In the figure, 31 is a drum-shaped electrophotographic photosensitive member according to claim 2 or 3 of the present invention. A corona charger 32 as a charging means is provided around the photosensitive member 31, and an image exposure light after charging. An exposure unit 33 that is an exposure unit that irradiates the
A developing device 35, which is a developing unit having a toner 34 for forming a toner image on the surface of 31, and a transfer for transferring the toner image 36 formed on the surface of the photoconductor 31 to a recording paper 37 which is a transfer material. A transfer device 38 as a means, a cleaning means 40 for removing the residual toner 39 on the surface of the photoconductor 31 after the transfer, and a discharging means 41 for removing the residual charge are arranged. Also,
The transfer toner image 42 transferred onto the recording paper 37 is fixed and fixed on the recording paper 37 by the fixing device 43 by heat or pressure to form a recorded image 44.

In this Carlson method, the following processes (1) to (4) are repeated.

The surface of the photoconductor 31 is charged by the corona charger 32.

By irradiating the image exposure light from the exposure device 33, an electrostatic latent image as a potential contrast is formed on the surface of the photoconductor 31.

This electrostatic latent image is developed by the toner 34 of the developing device 35. By this development, for example, black toner 34 adheres to the surface of the photoconductor 31 by electrostatic attraction with the electrostatic latent image,
The electrostatic latent image is visualized as a toner image 36.

An electric field having a polarity opposite to that of the toner 34 is applied from the back surface of the recording paper 37 to electrostatically transfer the toner image 36 on the surface of the photoconductor 31 onto the recording paper 37 to obtain a transferred toner image 42. This transfer toner image
The image 42 is fixed on the recording paper 37 by the fixing device 43 and the recorded image 44
Becomes

The residual toner 39 on the surface of the photoconductor 31 is removed by the cleaning means 40.

The entire surface of the photoconductor 31 is irradiated with the static elimination light by the static elimination means 41 to remove the residual electrostatic latent image.

Thus, according to the image forming apparatus 30 having the above structure, the photoconductor 31 according to claim 2 or 3 of the invention.
In, since the photocarriers generated inside the photosensitive layer by the light irradiation from the exposure device 33 move at a high speed inside the layer, the time when the electrostatic latent image is formed is shortened, and the drum-shaped photoreceptor 31 The rotation speed can be increased, and the image formation speed can be increased. Moreover, even in the charge removal by light irradiation after the transfer, the photocarriers generated inside the photosensitive layer immediately contribute to the charge removal, so that the area of the photosensitive layer required for the charge removal can be narrowed, which is combined with the speeding up of image formation. The diameter of the drum-shaped photoconductor 31 can be reduced, and the image forming apparatus can be downsized.

Although the image forming apparatus 30 is a printer, the image forming apparatus 30 can be used as a copying machine if an optical system such as a lens or a mirror for irradiating the reflected light from the original is used instead of the exposure device 33. It becomes an image forming apparatus.

[0071]

EXAMPLES Specific examples of the present invention will be described in detail below. The present invention is not limited to the following specific examples, and various modifications and improvements can be added without departing from the spirit of the present invention.

Example 1 89.1 g (3.88 mol) of sodium (Na) was put into 1.25 liter of toluene, and this was heated under reflux to prepare a sodium dispersion. When the reaction system was naturally cooled to about 65 ° C, 12.5 ml (0.0775 mol) of phenylmethyldichlorosilane, which is a starting material, was slowly added dropwise to carry out a polymerization reaction while maintaining the temperature at 65 ° C to obtain a polysilane compound. It was In the polysilane compound obtained by this polymerization reaction, x = 1, y = z
= 0, R ₁ = methyl group, R ₂ = phenyl group, degree of polymerization n =
It was 250. The chemical formula of this polysilane compound is
Shown in

[0073]

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The number average molecular weight Mn and the weight average molecular weight Mw were measured by gel permeation chromatography to find that Mw was about 30,000, and the ratio Mw of Mw and Mn was Mw.
/ Mn was about 4. The yield was 112 g,
The yield was 60%.

Example 2 Na7 in 1.25 liters of toluene
8.4 g (3.41 mol) and copper iodide (CuI) 2.95 g (15.5
(50 mmol) and heated to reflux, to which 250 ml of starting material phenylmethyldichlorosilane (1.55
(Mol) was added dropwise to carry out a polymerization reaction to obtain a polysilane compound represented by Chemical formula 3 having a polymerization degree different from that of [Example 1]. In the polysilane compound obtained by this polymerization reaction, x = 1, y = z = 0, R ₁ = methyl group, R ₂ =
The phenyl group had a degree of polymerization of n = 750, and its Mw was about 90,000 and Mw / Mn was about 10. The yield was 92 g, which was 49.4%.

[Example 3] In the same manner as in [Example 1] and [Example 2], toluene as a solvent was added to various dichlorosilanes as starting materials, and desorption with Na was performed at a reaction temperature of 65 to 110 ° C. Three kinds of polysilane compounds a-1 and a represented by the chemical formula 3 having different degrees of polymerization by carrying out a chlorination condensation reaction
-2, a-3, and x = 1 and y = displayed in the following chemical formula 4
polysilane compound b in which z = 0, R ₁ = methyl group, R ₂ = normal propyl group, x = y =
1, z = 0, polysilane compound c in which R ₁ , R ₂ , R ₃ = methyl group, R ₄ = phenyl group, x represented by Chemical formula 6
= 1, y = z = 0, x '= 1, y' = z '= 0, R ₁ ,
A polysilane compound d having R ₂ , R ₁ ′ = methyl group and R ₂ ′ = phenyl group was synthesized.

[0077]

Embedded image

[0078]

Embedded image

[0079]

[Chemical 6]

These polysilane compounds a-1, a-2, a
The carrier (hole) mobilities at −25 ° C. were calculated for Mw, Mw / Mn, and time of flight (TOF) for −3, b, c, and d, and the results are shown in Table 1.

[0081]

[Table 1]

From the results shown in Table 1, it can be seen that all the polysilane compounds have good carrier mobility.

[Example 4] The six kinds of polysilane compounds obtained in [Example 3] and polymethylmethacrylate (PMMA), which is an anionically polymerizable polymer, were each dissolved in toluene, and transparent 10 wt% toluene was used for each. A solution was made. When these 6 types of polysilane / toluene solutions and PMMA / toluene solutions were mixed, respectively, all of the mixed solutions rapidly turned cloudy to become opaque solutions. When a film was formed on the glass substrate by a bar coating method using these mixed solutions, a white turbid and opaque film was obtained although the film had the same components as the polysilane mixture of the present invention.

25 of each polysilane mixed film thus obtained
When the carrier mobility at ° C was measured, a decrease of 2 to 3 digits was observed from the value of the conventional polysilane compound, and even if the polysilane and the polymer resin were simply mixed, the compatibility between the two was poor, so that they were uniform. It was found that such a film could not be obtained and the function of polysilane could not be fully exhibited.

Example 5 Six types of polysilane compounds obtained in [Example 3] in toluene, methyl methacrylate as an anionically polymerizable monomer, and 1,1-diphenyl-3-dimethylpentyllithium as an initiator Was added, and a polymerization reaction of methyl methacrylate was performed at a reaction temperature of −78 ° C., respectively. After reacting for 3 hours, methanol was added to the reaction solution to stop the polymerization reaction. Then, these reaction solutions were taken out, and further methanol was added to obtain a polysilane / PMMA mixture. The molecular weight of this PMMA was about 200,000, and Mw / Mn showing the extent of the spread of the molecular weight was about 4. The weight ratio of polysilane to PMMA was about polysilane: PMMA = 1: 1.2.

When a film was formed using this polysilane mixture in the same manner as in [Example 4], a uniform transparent film was obtained in each mixed film.

The Mw and Mn of PMMA in each polysilane mixed film thus obtained were measured by gel permeation chromatography (detector: 254 nm). Moreover, the carrier mobility at 25 ° C. of each of the obtained polysilane mixed films was measured. Table 2 shows the results.

[0088]

[Table 2]

From the results in Table 2, it can be seen that carrier mobilities equal to or higher than those of conventional polysilane compounds were obtained in any of the polysilane mixtures.

It is considered that this is because polysilane and PMMA are sufficiently compatible at the molecular level.

[Example 6] Outer diameter of 30 mm as a translucent support
× Use a drum-shaped glass tube with a length of 300 mm and a wall thickness of 1.8 mm, and form an ITO layer as a transparent conductive layer on its peripheral surface by the active reactive vapor deposition method to a thickness of 1,000 Å to provide a transparent conductive layer. A permeable substrate 1 (10) was obtained. Next, this conductive substrate was immersed in a liquid in which titanyl phthalocyanine and a polyester resin were dispersed and mixed in chloroform, and then dried to form a photocarrier excitation layer 3 (11) made of titanyl phthalocyanine and having a thickness of 3 μm.

Next, a carrier-transporting layer 4 (12) composed of a mixture of 6 kinds of polysilanes of [Example 5] was laminated thereon to form a laminated type photosensitive layer 2 (13), and the electrophotographic image of the present invention was obtained. Photoconductors A to F were produced.

An electrophotographic photosensitive member G of Comparative Example was prepared in the same manner as above except that a carrier transport layer containing no polysilane compound was used for laminating the carrier transport layer.

This electrophotographic photosensitive member A was mounted in an image forming apparatus having an image forming section 8 having the structure shown in FIG. 3, and a two-component developer composed of a conductive magnetic carrier and an insulating toner was used as the developer. Also, the dynamic drive type LED array head with a resolution of 300 dpi (dots / inch)
14 is disposed, image exposure is performed at a wavelength of 660 nm while applying a voltage of Vs = + 400 V between the conductive sleeve 19 and the conductive substrate 10, and a toner image 23 is formed on the photoconductor 9. Then, the toner image 23 was transferred onto a plain paper recording paper 24 by the transfer roller 16 to which a transfer bias voltage of -400 V was applied, and heat fixing was performed to obtain a recorded image. In forming an image, the developer was rotated in the direction opposite to that of the photoconductor 9 to form the developer pool 26, and image exposure was performed on that portion.

When this image was evaluated, all of the electrophotographic photosensitive members A to F had an image density of 1.4 or more, no fog on the back, and a resolution of 300 dp.
It was a good image of i.

On the other hand, when the same image evaluation was performed using the electrophotographic photosensitive member G, in the photosensitive member B, since the carrier mobility in the carrier transporting layer was low, the photoresponsiveness was poor and a sufficient potential contrast was obtained. Since the toner image was not formed, a toner image having a sufficient density was not formed, and the image density was insufficient at 0.6.

[Example 7] In this example, an optical carrier excitation layer 3 (11) made of titanyl phthalocyanine was prepared in the same manner as in [Example 6] using a drum-shaped conductive substrate 1 (10) made of aluminum. The electrophotographic photosensitive material of the present invention having a photosensitive layer 2 (13) of a laminated type formed by laminating a carrier transporting layer 4 (12) having a thickness of 5 μm and comprising 6 kinds of polysilane mixture of [Example 5] thereon. The bodies A ′ to F ′ were produced.

The electrophotographic photoconductors A'to F'obtained as described above are mounted on the image forming apparatus 30 having the structure shown in FIG. 5, and charged by using the corona charger 32 to which a voltage of -6 kV is applied. Then, the surface potential of the dark part was measured and the initial charging potential was obtained. As a result, it was confirmed that each had a charging potential of −800 V and had a high charging ability.

Next, after charging so that the surface potential becomes -800 V, light having a wavelength of 650 nm is irradiated, and the exposure energy required to attenuate the surface potential from -500 V to -250 V ( half decay exposure) were measured, was determined half-light sensitivity its reciprocal, all exhibited about 2.0 cm ² / μJ, and the high light sensitivity.

Furthermore, when the exposure wavelength was changed over the range of 600 to 800 nm and the surface potential when the exposure amount twice the half exposure amount was given was obtained as the residual potential and the spectral sensitivity characteristics were examined. Also, it was as low as −10 V or less, and all showed excellent characteristics.

Next, the electrophotographic photoconductors A'to F'are mounted on the image forming apparatus 30 having the structure shown in FIG. 5, and a dynamic drive type LED array head 33 having a wavelength of 650 nm and a resolution of 400 dpi is used as an exposing means. An image was formed by using, and the image was evaluated for the image density, resolution, back fog, and afterimage (ghost).
As a result, in each of the electrophotographic photoconductors A ′ to F ′, the image density was as high as 1.4 and the resolution was 400 dp.
i was well resolved, there was no background fogging, and no afterimage was observed. The excellent photoresponsiveness made it possible to increase the rotation speed of the drum-shaped photoconductor 31. In addition, even when 10,000 sheets of images are continuously formed, no change in image quality such as a decrease in image density or resolution or an increase in background fog is observed, and the electrophotographic photoreceptors A ′ to F ′ are excellent. It was confirmed that it also has excellent durability.

[Example 8] The exposure means 33 of the image forming apparatus 30 shown in FIG. 3 is replaced with an optical system for irradiating the reflected light from the original, and an image forming apparatus configured as a copying machine has the same structure as that of [Example 7]. The electrophotographic photoconductors A ′ to F ′ were mounted and the image formation was performed in the same manner. As a result, image density, resolution, background fogging,
An image having excellent image quality in both gradation reproducibility and afterimage was obtained. Further, it was confirmed that the rotation speed of the drum-shaped photoconductor was increased due to the excellent photoresponsiveness, and that all had excellent properties as a photoconductor for a copying machine.

[0103]

As described in detail above, according to the polysilane mixture according to the first aspect of the present invention, anionic polymerization is carried out in the system in which the polysilane compound represented by Chemical formula 1 having no particular limitation on the molecular weight and the molecular weight distribution is present. It was possible to provide a polysilane mixture suitable for a material for a carrier transporting layer of an electrophotographic photosensitive member, which is excellent in electrophotographic properties, mechanical strength of a film, and film properties, by polymerizing a photosensitive monomer.

According to the polysilane mixture of the present invention, since the polysilane compound is mixed with the binder made of the polymer resin, the restriction on the molecular weight and the molecular weight distribution required for the conventional polysilane is eliminated, and a large amount and at a low cost. A polysilane mixture can be provided.

Further, according to the electrophotographic photosensitive member using the polysilane mixture of the present invention according to claim 2 or 3 of the present invention, it has a high hole mobility and further has a large film strength and adhesion. It was possible to provide an electrophotographic photosensitive member having excellent film characteristics.

The electrophotographic photosensitive member of the present invention could be suitably mounted in an image forming apparatus which requires high carrier mobility, for example, an image forming apparatus of the back exposure simultaneous development type.

Further, claim 4 or claim 5 of the present invention.
According to the image forming apparatus of the present invention, it is possible to provide an image forming apparatus using the above electrophotographic photosensitive member, which has high performance, high reliability, and can be further downsized.

Furthermore, according to the image forming apparatus of the present invention, the photocarriers generated inside the photosensitive layer by the light irradiation for image exposure move at a high speed inside the layer, so that an electrostatic latent image is formed. The time is shortened, and the rotation speed of the drum-shaped photoconductor can be increased, and the image formation can be performed at high speed. Moreover, the area of the photosensitive layer required for static elimination after transfer is narrowed, and the drum photosensitive drum can be made smaller in diameter in combination with the increase in rotation speed of the drum photosensitive member, thus achieving downsizing of the image forming apparatus. We were able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a layer structure of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a cross-sectional view showing another layer structure of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a schematic diagram showing an image forming unit of the image forming apparatus of the present invention.

FIG. 4 is a main part configuration diagram of an image forming unit of the image forming apparatus of the present invention.

FIG. 5 is a schematic diagram showing an image forming unit of another image forming apparatus of the present invention.

[Explanation of symbols]

1, 10 ... Conductive substrate, 2, 7, 13 ... Photosensitive layer,
3, 11 ... Photo carrier excitation layer, 4, 12 ... Carrier transport layer, 5 ... Carrier transport material, 6 ... Photo carrier excitation material, 8 ... Image forming part, 9, 31.・
.Electrophotographic photoreceptors, 14, 33 ... Exposure means, 15, 35
... Developing means, 16, 38 ... Transfer means, 17,41 ...
..Electrification removing means, 22 ... Bias power supply, 23, 36 ...
・ Toner image, 24,37 ・ ・ ・ Transfer material, 25,39 ・ ・ ・
Residual toner, 30 ... Image forming device, 40 ... Cleaning means

Claims (5)

[Claims] 1. A polysilane comprising a polysilane compound represented by the following chemical formula 1 and a binder produced by polymerizing an anionic polymerizable monomer selected from the following (A) in the presence of the polysilane compound. mixture. Embedded image (A) α-methylstyrene, butadiene, styrene, methacrylic acid ester, acrylic acid ester, acrylonitrile, nitrostyrene, ethyl α-cyanoacrylate, vinylidene cyanide 2. A photocarrier excitation layer on a conductive substrate,
An electrophotographic photoreceptor having a photosensitive layer formed by laminating the carrier transporting layer containing the polysilane mixture according to claim 1. 3. An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer comprising a carrier transport material comprising the polysilane mixture according to claim 1 and a photocarrier excitation material formed on the conductive substrate. 4. The conductive substrate is translucent.
The electrophotographic photoreceptor described above, a developing means disposed on the photosensitive layer side of the electrophotographic photoreceptor, and an exposing means for irradiating image exposure light from the conductive substrate side, and the electrophotographic photoreceptor. An image forming apparatus, wherein a voltage is applied between the developing means and the conductive substrate so that a toner image is formed on the surface of the surface, and the image exposing light is emitted from the exposing means. 5. The electrophotographic photosensitive member according to claim 2, a charging unit for applying a charge to the surface of the electrophotographic photosensitive member, and an exposure unit for irradiating the charged area of the electrophotographic photosensitive member with image exposure light. And an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member by these charging means and exposing means,
A developing unit that forms a toner image corresponding to the electrostatic latent image on the surface of the electrophotographic photosensitive member, a transfer unit that transfers the toner image to a transfer material, and a residual toner on the surface of the electrophotographic photosensitive member after the transfer. An image forming apparatus comprising: a cleaning unit that removes and a charge removing unit that removes a residual electrostatic latent image after the transfer.