JP3300783B2 - Polysilane compound for photoconductor, photoconductor containing polysilane compound, and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilane compound for a photoreceptor having increased hole mobility, a polysilane compound-containing photoreceptor having increased hole mobility and enhanced film strength, and an image forming apparatus equipped with the photoreceptor. It is about.

[0002]

2. Description of the Related Art Poly-N-vinylcarbazole (PVK) is used as a material for a carrier transport layer of an electrophotographic photosensitive member.
In recent years, low molecular weight compounds such as an anneal amine derivative and a hydrazone derivative have been dispersed in an inert polymer binder such as a polycarbonate resin in order to meet the demand for high mobility carriers. Molecular resin dispersed composite materials have been proposed.

However, the recent demand for a high carrier mobility in the material for the carrier transport layer is not yet a satisfactory condition, and a higher carrier mobility, particularly a higher hole mobility, is required.

In response to such a demand, it has been proposed to employ a polysilane compound as a material for a carrier transport layer of an electrophotographic photoreceptor (JP-A-2-33416, JP-A-2-9466).
No. 54). According to JP-A-2-133416, a hole-transporting substance comprising a block copolymer of a polymer block A composed of polysilane and a block B of a polymer of an anionic polymerizable monomer has been proposed. In the issue
Photoreceptive layers containing polysilane compounds have been proposed.

[0005]

However, the former publication discloses that the number average degree of polymerization of the polysilane of the polymer block A is 10 to 50,000, and the latter publication discloses that the weight average molecular weight is 6,000. However, there is no mention of the relationship between the weight average molecular weight and the number average molecular weight of the polysilane compound for improving the hole mobility and the film strength.

That is, this polysilane compound is a polymer having a Si-Si σ bond as a main chain and having two kinds of organic substituents as shown in the chemical formula (2). Various polymers can be produced up to the same degree of compound, and various polymers can be produced by combining the weight average molecular weight and the number average molecular weight. However, there is no description of the conditions for these combinations. In addition, there is also a copolymer (copolymer) of a monomer represented by the chemical formula shown in Chemical formula 2, and the combination thereof is further increased.

[0007]

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The present inventors focused on this degree of polymerization and worked diligently to conduct research, and as a result of repeating a number of experiments, the degree of polymerization was related to the hole mobility and the film strength. However, it was found that hole mobility and film strength were improved by reducing the number of compounds having a low polymerization degree.

The present invention has been accomplished based on the above findings, and an object of the present invention is to provide a polysilane compound for a photoreceptor having an improved hole mobility.

It is another object of the present invention to provide a photoreceptor containing a polysilane compound having improved hole mobility and film strength (durability).

Another object of the present invention is to provide a polysilane compound-containing photoreceptor having excellent reliability by stably producing a required polysilane compound.

Still another object of the present invention is to provide an image forming apparatus using a highly reliable and high-performance photoconductor containing a polysilane compound as described above.

[0013]

The polysilane compound for a photoreceptor according to claim 1 has a weight average molecular weight of 50,000 to 2,500,000 represented by the following formula 1 and a ratio of 10 or less to the number average molecular weight. A polysilane compound, wherein R
_At least one of R _{1 to} R ₆ is an aryl group, has a hole mobility of 10 ⁻⁵ cm ² / V · sec or more, and is arranged at a position away from the aryl group so that dimer sites are not formed. It is characterized by the following.

[0014]

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According to a second aspect of the present invention, there is provided a photoreceptor containing a polysilane compound, wherein a photosensitive layer is formed by laminating a photocarrier excitation layer and a carrier transporting layer comprising the polysilane compound on a conductive substrate. .

The photoreceptor containing a polysilane compound according to a third aspect of the present invention is the photoreceptor according to the second aspect, wherein the photoreceptor is replaced with a photoreceptor layer comprising a lamination of a photocarrier excitation layer and a carrier transport layer.
A photosensitive layer containing a particulate photocarrier exciter in a carrier transporter made of a polysilane compound is formed.

According to a fourth aspect of the present invention, there is provided an image forming apparatus, comprising: the photoreceptor of claim 2 or 3; a developing unit disposed on the photosensitive layer side of the photoreceptor; Exposure means for irradiating light, and irradiating image exposure light from the exposure means while applying a voltage between the developing means and the conductive substrate to form a toner image on the surface of the photoreceptor. It is characterized by having done.

According to a fifth aspect of the present invention, there is provided an image forming apparatus according to the second or third aspect, a charging unit for applying a charge to the surface of the photoconductor, and an exposing unit for irradiating the charged area of the photoconductor with light. A developing unit for forming a toner image corresponding to the electrostatic latent image on the surface of the photoreceptor, while forming an electrostatic latent image on the surface of the photoreceptor by the charging unit and the exposing unit; The image forming apparatus is characterized in that a transfer means for transferring to a transfer material, a cleaning means for removing residual toner on the surface of the photoreceptor after transfer, and a charge removing means for removing residual electrostatic latent image after transfer are provided.

[0019]

According to the present invention, as described above, by reducing the number of compounds having a low degree of polymerization, the number of compounds having a high degree of polymerization is specified by the weight-average molecular weight Mw, and the molecular weight distribution is broadened. Is specified by specifying Mw / Mn, which is the ratio to the number average molecular weight Mn, and a polysilane compound for a photoconductor having excellent hole mobility can be obtained by these two limitations.

The polysilane compound of the present invention has a hole mobility of 10 ⁻⁵ cm ² / V · sec or more. Further, by appropriately selecting the molecular structure of the monomer and Mw and Mn, 10 ⁻⁴ cm ² / V. V · sec or more.

Further, the present inventors have determined that the weight average molecular weight Mw
It has also been found that the strength of this polysilane compound can be remarkably increased by increasing the molecular weight distribution to a narrow range. Based on this finding, the present invention provides a polysilane compound-containing photoconductor excellent in hole mobility and film strength by forming a carrier transport layer composed of the above-described photoconductor polysilane compound as a surface layer of the photoconductor. Can be provided.

According to experiments repeatedly conducted by the present inventors, the weight average molecular weight Mw was 50,000 to 2,500,
000, preferably 200,000 to 2,000,000
And the weight average molecular weight Mw is 50,000.
If it is less than the above, it has been found that the hole mobility is reduced, and further, excellent strength with high durability cannot be obtained. On the other hand, when the Mw exceeds 2,500,000, the polysilane compound is not completely dissolved in the solvent, and it is difficult to form a uniform film.

Further, Mw / M representing the spread of the molecular weight distribution.
The value of n is preferably 10 or less, and more preferably 5 or less, and within this range, the object of the present invention can be achieved advantageously.

Further, according to the image forming apparatus of the fourth and fifth aspects, the photosensitive member having a high carrier mobility is mounted, so that a high-speed image can be formed.
The device itself becomes smaller.

That is, the carriers generated in the photosensitive layer by the light irradiation of the exposure means move at a high speed inside the layer, so that the time for forming the electrostatic latent image is shortened, and as a result, the drum-shaped If the photosensitive member is used, the rotation speed of the drum can be increased, and the image formation can be performed at a high speed.
In addition, even in the charge removal by exposure after transfer, the carrier generated inside the photosensitive layer quickly contributes to charge removal, so the area of the photosensitive layer required for charge removal is narrowed, and the drum shape is increased in conjunction with the higher speed of the photosensitive drum. The diameter of the photoconductor can be reduced, and the size of the image forming apparatus can be reduced.

[0026]

The present invention will be described below with reference to examples. (Structure of Polysilane Compound) In addition to hydrogen, R _{1 to} R ₆ of the polysilane compound shown in Chemical Formula 1 represent an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxy group,
There are substituted alkoxy groups. Examples of the alkyl group, aryl group, and alkoxy group include, for example, methyl, ethyl,
Propyl, butyl, amyl, hexyl, octyl, nonyl, decyl, pentadecyl, stearyl, cyclohexyl, phenyl, tolyl, xylyl, naphthyl, methoxy, ethoxy and the like. These substituents include alkyl, aryl, halogen, nitro, amino, alkoxy, cyano and the like.

In the polysilane of the present invention, as shown in Chemical formula 1, x, y, and z are represented by 0 or 1 to indicate the presence or absence of each unit. For example, x = y
= 1 and z = 0, the composition is such that two types of units are alternately and continuously arranged.

The polysilane compound of the present invention is
As shown in the above, a copolymer (copolymer) of the polysilane compound of Chemical formula 1 may be used. According to Formula 3, x, y, z, x ′,
y 'and z' are selectively set to 0 or 1, and several combinations can be made depending on the presence or absence of each unit. That is, a polymer composed of three types of monomers and 3
Compounds with polymers consisting of three types of monomers, polymers consisting of three types of monomers and 2
Compounds with polymers consisting of three types of monomers, polymers consisting of three types of monomers and 1
Compound with a polymer consisting of two kinds of monomers, a polymer consisting of two kinds of monomers and 2
Compound with a polymer consisting of two types of monomers, a polymer consisting of two types of monomers and 1
Compounds with a polymer consisting of one type of monomer, a polymer consisting of one type of monomer and one
There are compounds with polymers consisting of monomers of different kinds. Furthermore, there are compounds obtained by combining these compounds.

[0029]

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The polysilane compound of the present invention has various monomers as described above. Especially, when intensive studies have been made on the molecular structures of some of the monomers, the reason that high hole mobility can be obtained is as follows. It has been found that a dimer site due to an aromatic ring is not formed, and a structural hole trap cannot be formed.

That is, the present inventors have experimentally confirmed that the presence of an aryl group is desirable in order to obtain a large carrier mobility. On the other hand, the aryl substituent has the effect of increasing the activation energy E _0. And E _{0 of} the aromatic substituent present on the adjacent Si is 0.34 to 0.36 e
V, and when E ₀ of the aliphatic substituents is 0.22 eV, a high structural regularity having an aromatic substituent in the Si atoms every is sure E ₀ is 0.26 eV, the The magnitude of E ₀ is an index indicating the depth of the trap of the Poole-Frenkel type hopping conduction. According to the experiment repeatedly performed by the present inventors, E 0 due to the presence of the aryl group is determined.
The increase of ₀ was found to be due to the formation of dimer sites by adjacent aromatic rings.

Therefore, the presence of an aryl group as a substituent of R _{1 to} R ₆ is desirable. On the other hand, in order to reduce the activation energy E ₀ , an aromatic substituent cannot be formed at a distant position where a dimer site cannot be formed. It was found that it should be placed in

(Structure of Photoconductor) FIGS. 1 and 2 show a basic layer structure of the photoconductor of the present invention. FIG. 1 shows an example in which a laminated photosensitive layer 2 is formed on a conductive substrate 1. The photosensitive layer 2 includes a photocarrier excitation layer 3 and a carrier transport layer 4 made of polysilane, and the order of the layers 3 and 4 may be changed. FIG. 2 shows a single photosensitive layer 7 in which a carrier carrier 5 made of polysilane contains a particulate photocarrier exciter 6.

The conductive substrate 1 is made of copper, brass, SUS,
In the image forming apparatus according to claim 4, there is a metal conductor such as Al or Ni, or an insulator such as glass or ceramic coated with a conductive thin film.
A configuration in which a transparent conductive layer is formed on a transparent insulating substrate is employed.

The substrate 1 may be a sheet-shaped, belt-shaped or web-shaped flexible conductive sheet. Such a sheet may be a metal sheet such as SUS, Al, Ni, or a polymer resin such as polyester, nylon, or polyimide. A film is used in which a metal such as Al or Ni, or a transparent conductive material such as indium tin oxide (ITO) or an organic conductive material is coated on the film by vapor deposition or the like and subjected to a conductive treatment.

As a constituent material of the photocarrier excitation layer 3 and the photocarrier excitation body 6, an organic or inorganic photoconductive material known per se can be used. Organic carriers having high carrier generation efficiency using, for example, titanyl phthalocyanine, metal phthalocyanine pigments, metal-free phthalocyanine, perylene pigments, polycyclic quinone pigments, squarylium dyes, azurenium dyes, thiapyrylium dyes, trisazo pigments, etc. as organic photoconductive materials An optical semiconductor is chosen.
In the case of an inorganic photoconductive material, for example, amorphous Se or S
eAs, SeTe or Si (a-Se, a-SeA
s, a-SeTe, a-Si), CdS, ZnO and the like. If the photocarrier excitation layer 3 is to be formed, a vacuum deposition method, an active reactive deposition method, an ion plating method, an RF sputtering method, a DC sputtering method,
It is performed by an RF magnetron sputtering method, a DC magnetron sputtering method, a thermal CVD method, a plasma CVD method, or the like.

When the photocarrier excitation layer 3 is formed of a-Si, carbon, nitrogen, oxygen, and germanium are added thereto to form amorphous SiC and Si.
It may be a layer of N, SiO, or SiGe. In addition, when a layer containing an element such as B or P which is an impurity element for controlling conductivity is formed in these layers, a function such as a carrier injection blocking layer can be provided.

When an a-Si-based powder is used as the granular photocarrier exciter 6 of the photosensitive layer 7, this powder can be prepared in the same manner as the a-Si-based photocarrier excitation layer 2.
Granules, columns, spheres, and flakes. Its diameter is 0.0
It may be 5 to 5 μm, preferably 0.1 to 3 μm, and the powder is 1 to 80% by weight in the layer, preferably 5 to 6%.
It is good to make it contain at 0% by weight.
It is dispersed by a stirring method, an ultrasonic dispersion method or the like.

In addition, titanyl phthalocyanine (TiO)
The photosensitive layer 7 may be prepared by dispersing Pc (abbreviated as Pc) in polysilane, and can have high sensitivity particularly to image exposure on the long wavelength side. This TiOPc is the raw material T
The iOPc pigment is subjected to a purification treatment such as sublimation purification or purification with an acid or alkali, and is kneaded with various kinds of dispersers together with a grinding aid, a solvent, or the like, or is recovered in fine particles by a steam method. , And then dispersed in polysilane using various solvents. The content of TiOPc is 1 to 80% by weight, preferably 10 to 60% by weight in the layer.

The photoreceptor of the present invention may be further improved or changed in accordance with the required electrophotographic characteristics based on the above basic constitution. For example, by providing an intermediate layer between the 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 these photosensitive layers 2 and 7 to enhance the chargeability and the durability thereof.

(Method of Forming Polysilane Layer) The carrier transporting layer 4 and the photosensitive layer 7, which are polysilane layers, can be formed by various known methods.
The polysilane is formed into a solution by an organic solvent, and the resulting solution is applied and dried by a coating method such as a bar coating method, a dipping method, a melt extrusion method, and a spray method. Examples of the organic solvent include aromatic hydrocarbons such as benzene and toluene, alcohols such as methyl alcohol, ethyl alcohol and IPA, ethers such as tetrahydrofuran and dimethyl ether, ketones such as acetone and methyl ethyl ketone, esters, and halogens. , Halogenated hydrocarbons and the like are used, and they are used alone or in combination of two or more.

Further, a solution in which a low molecular carrier transporting agent is added to polysilane together with the above organic solvent may be prepared, immersed in this solution, and then dried to form a layer. Examples of the transport agent include phenylenediamine compounds, oxadiazole compounds, styryl compounds, pyrazoline compounds, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, and thiazole compounds. ,
There are nitrogen-containing cyclic compounds such as thiadiazole compounds, imidazole compounds, pyrazole compounds and triazole compounds, and condensed polycyclic compounds.

These low molecular weight carrier transporting agents are preferably contained in an amount of 1 to 60% by weight, preferably 5 to 50% by weight, based on the polysilane layer. , Has a superior effect on light sensitivity and residual potential, and has relatively high charging ability, thereby improving sensitivity characteristics.

Furthermore, the polysilane compound of the present invention can provide high carrier mobility and high film strength. However, in order to further increase the strength and hardness, or to prevent light fatigue due to prolonged exposure to light (carrier mobility and film strength). Drop)
You may put a binder resin. As such a binder resin, those known per se, for example, polystyrene, polyvinyl chloride, polypropylene, polyamide, polyimide, polyester, polyether, polyurethane, epoxy resin, polycarbonate, polyacrylate, polyarylate, silicone resin, polyvinyl butyral and so on. These resins can be used alone or in combination of two or more. Except for a very transparent resin such as a methacrylate resin, many of the resins themselves absorb ultraviolet rays, so that deterioration of polysilane due to ultraviolet rays can be prevented.

(Type of Image Forming Apparatus) An image forming apparatus equipped with the photoreceptor of the present invention forms an electrostatic latent image on the surface of the photoreceptor by charging or voltage application and exposure to form an image. If the process is adopted, there are various types of apparatuses, for example, an optical backside exposure type, an external charge latent image type such as the Carlson method or the capacitance image method (NP method, KIP
Law). In these electrophotographic image forming apparatuses, a carrier transport layer having high mobility can be formed on the photoreceptor of the present invention mounted thereon, so that the carriers generated inside the photosensitive layer move at high speed inside the layer. , The time required to form an electrostatic latent image is shortened. As a result, the rotation speed of the drum-shaped photoconductor can be increased, and image formation can be performed at a high speed. In addition, even in the charge removal by exposure after transfer, the carrier generated inside the photosensitive layer quickly contributes to charge removal, so the area of the photosensitive layer required for charge removal is narrowed, and the drum shape is increased in conjunction with the higher speed of the photosensitive drum. The diameter of the photoconductor can be reduced, and the size of the image forming apparatus can be reduced.

Further, these various types of image forming apparatuses are
Either can be configured as a copier or printer. Here, a copying machine has a structure in which light reflected from a document is exposed to the surface of a photoreceptor using an optical system such as a lens or a mirror, and a printer is a light emitting light source controlled by an electric signal. (Laser, LED, LCD shutter,
EL, etc.) to expose the surface of the photoreceptor.

(Light Back Exposure Method) Next, an image forming apparatus (printer) of the light back exposure method to which the features of the present invention can be most applied will be described in detail. FIG. 3 is a schematic view showing the image forming apparatus 8 of the optical backside exposure method, which is an electrophotographic image forming apparatus in which corona charging is unnecessary and exposure and development can be performed almost simultaneously.
Reference numeral 9 denotes a drum-like structure in which a light-transmitting conductive layer 11, a photocarrier excitation layer 12, and a carrier transporting layer 13 having a mobility of 10 ⁻⁵ cm ² / V · sec or more are laminated on a light-transmitting support 10. A photoreceptor, 14 is an LED head as exposure means, 15 is a developing machine as developing means, and 16 is a transfer roller as transfer means. The LED head 14 and the developing device 15 are
Are arranged substantially symmetrically through a certain portion. As such an LED head 14, a small and low power consumption dynamic drive type LED head is preferably used. Reference numeral 17 denotes L as an erasing light source serving as a static elimination means.
It is an ED array and may be arranged outside the photoconductor 9.
Also, 17 is not always required. In the developing device 15, for example, an eight-pole cylindrical magnetic pole roller 18 is provided.
A one-component magnetic conductive toner or a conductive magnetic carrier as a developer stored in a toner receiver 20 and an insulating toner. Is delivered to the outer periphery of the sleeve 19 to form the magnetic brush 21.
Further, a bias power supply 22 is provided between the sleeve 19 and the light-transmitting conductive layer 11, and a positive or negative voltage (300 V) is applied between the two according to the potential characteristics of the photoconductor 9.
Below). Reference numeral 23 denotes a toner image formed on the surface of the photoconductor 9, reference numeral 24 denotes a recording sheet as a material to be transferred, and reference numeral 25 denotes residual toner after transfer. In addition, a rotation driving unit for the developing machine and a rotation unit for the photoconductor 9 are provided. Although an LED head is used here as the exposure means 14, a laser, a liquid crystal shutter, an EL head, or the like may be used. The erasing light source 17 also includes an LED array, a halogen lamp, a fluorescent lamp, and an EL.
Light sources such as arrays can be used.

Thus, according to the image forming apparatus 8 having the above-described configuration, the LED is disposed on the rotating photosensitive member 9 from the side of the translucent support 10.
When the head 14 irradiates light for image exposure to generate holes and electrons inside the photocarrier excitation layer 12, if a + bias voltage is applied to the developing device side, the electrons are generated by the bias voltage. Move to the surface side of the transport layer 13,
The positive charges at the ends of the magnetic brush 21 cancel each other, and the toner adheres to the surface of the photoconductor 9. Then, the toner is transferred onto the recording paper 24 by the transfer roller 16 and then fixed.

In the present invention, the photocarrier excitation layer 12
And the carrier transport layer 13 made of polysilane, and the mobility of the carrier transport layer 13 is 1
The carrier is set to 0 ^-5 cm ² / V · sec or more to provide high carrier transport characteristics, whereby carriers generated in the optical carrier excitation layer 12 are efficiently transported to the surface of the carrier transport layer 13. And a high image forming speed can be obtained.

Next, the specific contents of the image forming apparatus having the above configuration will be described in more detail with reference to FIG. FIG. 4 is an explanatory view showing a part of the photoconductor 9 and a developer reservoir 26 formed by the developing device 15. The developing device 15 for holding the developer includes a conductive sleeve 19 and the magnetic pole roller 1 disposed therein.
8, the developer may be transported by rotating the sleeve 19 while fixing the magnetic pole roller 18 or
9, the magnetic pole roller 18 inside may be rotated.

Here, when the developer is conveyed in the opposite direction to the photosensitive member 9, the friction between the two causes the developer to be located downstream (the side where the photosensitive member is separated from the developer) downstream of the closest part between the developing device 15 and the photosensitive member 9. A pool 26 is created. That is, the portion of the developer protruding beyond the original height is the developer reservoir 26, and the transport speed of the developer, the height of the developer, the gap between the sleeve 19 and the surface of the photoconductor 9, and the like are changed. Is appropriately set in accordance with the rotation speed of the developer and the required size of the developer reservoir 26.

Reference numeral 27 denotes a control electrode.
Is provided on the sleeve 19 at a position closest to the photosensitive member 9, and is insulated from the sleeve 19 by the insulator 28. The control electrode 27
The sleeve 19 has a belt-like shape along the length direction so that a uniform electric field is applied to the photoconductor 9 and the developer. This control electrode 2
7 is not indispensable, and is appropriately adopted.

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

The position where the image exposure is performed is not the closest position A between the surface of the photosensitive member 9 and the developing sleeve 19 but the position B of the developer reservoir 26 formed on the downstream side by the reverse rotation of the photosensitive member 9. Preferably, it is the latter half of the developer reservoir 26 on the downstream side. By performing the exposure at the position of the developer reservoir 26, the photosensitive member 9 is sufficiently charged before the exposure, and the influence of the potential history of the photosensitive member 9 before charging is suppressed. The toner remaining on the surface and the toner in the image background are sufficiently collected. Further, since the photosensitive member 9 is sufficiently charged and exposed to light to eliminate the charge, the electric attraction between the developer and the photosensitive member 9 is strong, and a good toner image 23 is formed. After the formation of the toner image 23, the photoconductor 9 is quickly separated from the developer reservoir 26, so that the toner image 23 on the surface of the photoconductor 9 is disturbed by mechanical force such as collision or friction of the developer. Without
A toner image 23 with good resolution is obtained.

At the position of the developer reservoir 26, the position of the developing sleeve 19 is smaller than the position A where the surface of the photosensitive member 9 is closest to the developing sleeve 19.
The distance between the surface of the photoconductor 9 and the magnetic pole roller 18 increases.
Therefore, the magnetic force for attracting the developer toward the magnetic pole roller 18 is weak, and a part of the toner image 23 formed on the surface of the photoreceptor 9 is collected by the magnetic force toward the developing unit, and the image density is reduced. In addition, it is possible to prevent the resolution from being lowered by being disturbed by the magnetic force. Further, a strip-shaped control electrode 27 is provided,
The potential is adjusted to a predetermined potential by the power supply 29. For example, the control electrode 27 is grounded and set to a common potential with the translucent conductive layer 11. Alternatively, the potential is set lower or higher than the potential of the sleeve 19.

By providing the control electrode 27 to which a potential can be applied independently of the sleeve 19 as described above, the surface potential of the photosensitive member 9 is neutralized through a developer, or the potential of the surface of the photosensitive member 9 is made uniform. The influence of the history of the photoconductor 9 due to the presence or absence of charging, exposure, and the like in the previous process can be canceled. As a result, when repeatedly used, for example, when the photoconductor 9 is rotated several times to obtain one image, a stable developed state and a recorded image can be obtained. Here, by adjusting the potential of the control electrode 27, it is possible to adjust and obtain the optimum image forming conditions for the image density, the background fog, and the like. In addition, control electrode 2
By raising the potential of the sleeve 7 and lowering the potential of the sleeve 19, the toner adheres to the non-exposed area and the toner does not adhere to the exposed area, so-called reversal development has become possible.

The toner image 23 formed on the surface of the photosensitive member 9
Is transferred to a recording paper 24 and fixed thereon to form a recorded image. The residual toner 25 remaining on the surface of the photoreceptor 9 without being transferred is collected and reused by the developing device 15 in the next image forming process. .

Further, by irradiating the photoreceptor 9 after transfer with static elimination light from the erase light source 17, the influence of the history of the photoreceptor 9 due to the charging or exposure in the previous process is more effectively canceled. It is possible to suppress a problem on an image such as an afterimage phenomenon at the time of repeated use. In addition, the charge trapped on the surface of the carrier transport layer 13 of the photoconductor 9 is erased, the electric attraction between the photoconductor 9 and the residual toner on the surface is eliminated, and the residual toner is easily collected by the developing device 15. can do.

This carrier transport layer 13 is
Good surface characteristics can be provided even when the surface layer also serves as the surface layer.

That is, the polysilane compound of the present invention has a feature that the surface is hard and has an appropriate slipperiness, and is excellent in abrasion resistance, printing durability and charging characteristics. This is advantageous as a surface layer for a photoreceptor.
When the carrier transport layer 13 contains a low-molecular carrier transport agent, the mechanical strength in the low content region can be increased by reducing the content of the carrier transport agent on the surface side. In addition, the carrier transport agent can be hardly deteriorated due to intrusion from the surface due to the chemical action, and the degree of the deterioration can be reduced. Characteristics are obtained.

According to experiments repeatedly conducted by the present inventors, when the polysilane-based carrier transporting layer 13 according to the present invention was formed, the hardness of the surface thereof was Rockwell hardness M60.
The above values were obtained. In addition, the relative dielectric constant becomes 3 or less, and the repetition durability and the response of charging and erasing become suitable.

(External Charge Latent Image Method) The external charge latent image method includes a Carlson method and a capacitance image method (NP method, KIP method).
As a typical example, this Carlson method is shown in FIG.
This will be described below. FIG. 1 shows an image forming apparatus 30 having a printer configuration. Reference numeral 31 denotes a drum-shaped photoreceptor according to the present invention. A corona charger 32 serving as a charging unit is provided on the peripheral surface of the photoreceptor 31. Exposure device 33, a developing device 35 having a toner 34 for forming a toner image on the surface of the photoreceptor 31, and a transfer device for transferring the toner image to a transfer material 36 , A cleaning unit 38 for removing the residual toner on the surface of the photoreceptor after the transfer, and a charge removing unit 39 for removing the residual electrostatic latent image after the transfer.
Reference numeral 40 denotes a fixing device for fixing the toner image transferred to the transfer material 36 by heat or pressure.

In the Carlson method, the following processes are repeated. The peripheral surface of the photoconductor 31 is charged by the corona charger 32. By exposing the image with the exposure device 33, an electrostatic latent image is formed on the surface of the photoconductor 31 as a potential contrast. This electrostatic latent image is developed by the developing device 35. By this development, the black toner adheres to the surface of the photoreceptor by electrostatic attraction with the electrostatic latent image and is visualized. The toner image on the surface of the photoreceptor is electrostatically transferred from the back surface of the transfer material 36 such as paper by applying an electric field having a polarity opposite to that of the toner, thereby obtaining an image on the transfer material 36. The cleaning unit 38 mechanically removes residual toner on the surface of the photoconductor. The entire surface of the photoreceptor is exposed to intense light, and the remaining electrostatic latent image is removed by the charge removing means 39.

Thus, according to the image forming apparatus 30 having the above structure, the carriers generated in the photosensitive layer by the light irradiation of the exposing device 33 move at a high speed in the layer, so that an electrostatic latent image is formed. The rotation time of the drum-shaped photoconductor 31 can be increased, and the image formation can be performed at a high speed. In addition, even in the charge removal by exposure after transfer, the carrier generated inside the photosensitive layer quickly contributes to charge removal, so the area of the photosensitive layer required for charge removal is narrowed, and the drum shape is increased in conjunction with the higher speed of the photosensitive drum. The diameter of the photoconductor can be reduced, and the size of the image forming apparatus can be reduced.

The image forming apparatus 30 has a printer configuration. However, if an optical system such as a lens or a mirror that transmits reflected light from a document is used instead of the exposure unit 33, the image forming apparatus 30 can be used as a copier. Become.

Hereinafter, embodiments of the present invention will be described. (Example 1) In this example, toluene as a solvent was added to various kinds of dichlorosilane as starting materials, and 110 ° C.
Thus, a dechlorination-condensation reaction with sodium was performed, whereby various polysilanes represented by Chemical Formulas 4 to 6 were synthesized. And the weight average molecular weight Mw of these polysilanes
And the number average molecular weight Mn were measured, and Mw / Mn was also determined. The results shown in Table 1 were obtained.

Each of these average molecular weights Mw and Mn is measured by gel permeation chromatography, and columns for that purpose are Asahipak GS-310, GS-510, G
SM-700 was used, and tetrahydrofuran (THF) was used as a mobile phase.
It was measured with a detector of nm absorption. The chromatographic waveform processing was performed using waveform processing software called a chromatographic coder.

In the chemical formula 4, x = 1, y = z = 0, R ₁ is a methyl group, R ₂ is a phenyl group, and three kinds of polysilane compounds a-1 and a -2,
a-3 was synthesized. In the chemical formula 5, x = y = 1, z =
0, R ₁ , R ₂ , and R ₃ are methyl groups, R ₄ is a phenyl group, and two kinds of polysilane compounds b-1 and b-2 having different degrees of polymerization n were synthesized. In the chemical formula 6, x = y
= Z = 1, R ₁ , R ₂ , R ₅ , R ₆ are methyl groups,
A polysilane compound c in which R ₃ and R ₄ are phenyl groups was synthesized.

[0069]

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[0070]

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[0071]

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[0072]

[Table 1]

The carrier mobilities (25 ° C.) of the six kinds of polysilane compounds thus obtained were measured.
As shown in FIG. The carrier mobility is measured by a time-off flight (TOF). According to the TOF, a parylene blocking electrode is provided on an Al substrate, and an a-Se layer as a carrier excitation layer is further formed. A layer of each of the above polysilane compounds (thickness: 10 μm) is applied and formed on a film substrate, and a DC pulse voltage having a pulse width of 10 m.sec is applied to a sample having such a configuration to apply a uniform electric field to the sample. After applying an electric field, the sample was irradiated with an N ₂ laser-excited dye (coumarin 481 nm) laser pulsed light at 4 m.sec onto the electrode side of the sample with an optical fiber. State that the carrier drifts due to the applied electric field,
This is a method of observing as a transient change of the external current.

Each of the polysilane compounds a-1 according to the present invention,
With b-1, b-2, and c, it is understood that high hole mobility is obtained. However, the polysilane compound a-2 whose Mw / Mn is out of the range of the present invention, Mw and Mw /
In the polysilane compound a-3 in which both Mn are out of the range of the present invention, high hole mobility was not obtained.

(Example 2) Next, a transparent conductive layer 11 was formed on the peripheral surface of a transparent cylindrical glass substrate or plastic.
A TO layer is formed with a thickness of 1000 A by an active reactive deposition method,
Next, a photocarrier excitation layer 12 of titanyl phthalocyanine having a thickness of 15 μm was formed thereon by dipping in a liquid obtained by dispersing and mixing titanyl phthalocyanine and a polyester resin in methylene chloride and then drying at 55 ° C. under reduced pressure. Next, on the film-formed cylindrical glass substrate, six types of 5 μm-thick polysilane-based carrier transport layers 13 corresponding to the six types of polysilane compounds of (Example 1) were formed. A-2, A-3, B-1, B-2, and C were produced.

For example, in the case of the photosensitive members B-1 and B-2,
The film-formed cylindrical glass substrate on which the photocarrier excitation layer 12 is formed is immersed in a solution obtained by dissolving poly (trimethylphenyldisilane) obtained by dechlorination polymerization of 1,2-dichlorotrimethylphenyldisilane in toluene, Then 1
It dried with the hot air of 00 degreeC. As a result, a 5 μm-thick polysilane-based carrier transporting layer 13 made of the polysilane compound b-1 or b-2 was formed.
1, B-2 were obtained.

Therefore, the photoreceptors A-1 and B of the present invention are
-1, B-2, and C are mounted in an image forming apparatus 8 as shown in FIG. 3, and a two-component developer including a conductive magnetic carrier and an insulating toner is used as a developer. 300 dpi resolution (dot / dot)
Inch) LED head and sleeve 19
A voltage of Vs = −70 V is applied between the light-transmitting conductive layer 11, image exposure is performed at a wavelength of 740 nm, a toner image is formed on a photoconductor, and a transfer bias voltage of +200 V is applied to the toner image. The image was transferred to a commercially available plain paper by the transfer roller and heat-fixed to obtain an image. In addition, the developing agent is
The developer reservoir 26 was formed by rotating in the opposite direction to that described above, and the portion was exposed.

When this image was evaluated, the optical density (hereinafter, referred to as OD) was 1.
The image had an image density of 4 or more, had no fogging of the background, and had a good resolution of 300 DPI.

The photosensitive members A-2 and A-2 of the comparative examples
When -3 was evaluated in the same manner as described above, the photo-response was poor due to low carrier mobility in the carrier transport layer, and a sufficient density contrast was not formed because a sufficient potential contrast was not formed. O. D. Was an insufficient image with an image density of 0.6.

(Example 3) In this example, the durability of the six types of photosensitive members of (Example 2) is determined by using an image forming apparatus 8 as shown in FIG.
Was evaluated using Image forming apparatus 8 equipped with each photoconductor
After printing 10,000 sheets, the occurrence of scratches on the surface of the photosensitive layer was visually checked. The results shown in Table 2 were obtained. In the same table, ○ indicates that no scratches occurred, and ○ indicates that slight scratches occurred, but there is no practical problem, and Δ indicates that scratches occurred. However, this is a case where a slight hindrance occurs in practical use, and a cross mark indicates a case where the flaw is remarkably generated and hinders in practical use.

[0081]

[Table 2]

As is evident from the results shown in Table 2, it can be seen that all the photosensitive members of the present invention have excellent film strength and excellent durability.

(Example 4) The transparent conductive layer 11 is formed on the peripheral surface of a transparent cylindrical glass substrate (or cylindrical plastic substrate).
The ITO layer was formed to a thickness of 1000A by active reaction deposition method as, then mounted in a glow discharge decomposition apparatus, after drawing completely vacuum the reaction vessel, and the first SiH ₄ gas B
_A discharge voltage was applied while flowing ₂ H ₆ gas at a constant rate to form a 0.5 μm thick a-Si · B · H carrier injection blocking layer. After that, the injection of the B ₂ H ₆ gas was stopped, and the SiH
_The photocarrier excitation layer 12 having a thickness of 2 μm was formed by controlling the _four gases at a constant flow rate. Next, this film-formed cylindrical glass substrate is
Similarly to the six types of photoconductors of (Example 2), six types of polysilane-based carrier transport layers 13 having a thickness of 5 μm corresponding to the six types of polysilane compounds of (Example 1) were formed.
1, A = 2, A = 3, B = 1, B = 2, C = 1.

Therefore, the photoreceptor of the present invention, A = 1, B
= 1, B = 2, and C = 1 are mounted on the image forming apparatus 8 as shown in FIG. 3, respectively, and a toner image is similarly formed on the photoconductor under the conditions described in (Example 2). The toner image was transferred to commercially available plain paper by a transfer roller, and heat-fixed to obtain an image.

When this image was evaluated, the O.D. D. Has an image density of 1.4 or more,
There was no fogging of the back, and the image had a good resolution of 300 DPI.

However, the photosensitive member of the comparative example A = 2, A
= 3, the image response was evaluated in the same manner as described above. As a result, the photo-responsiveness was poor due to the low carrier mobility in the carrier transport layer, and a toner image of a sufficient density was not formed because a sufficient potential contrast was not formed. O. D. Was an insufficient image with an image density of 0.7.

(Example 5) In this example, when the durability of the six types of photosensitive members of (Example 4) was evaluated in the same manner as in (Example 3), similar results were obtained. If any, it was found that each of them had excellent film strength and good durability.

(Example 6) The transparent conductive layer 11 is formed on the peripheral surface of a transparent cylindrical glass substrate (or cylindrical plastic substrate).
An ITO layer was formed to a thickness of 1000 A by an active reactive evaporation method, and then a 2 μm layer of a-Se was formed by a vacuum evaporation method.
An m-thick photocarrier excitation layer 12 was formed. Next, six 5 μm-thick polysilane-based carrier transport layers 13 corresponding to the six polysilane compounds of (Example 1) were formed on the film-formed cylindrical glass substrate in the same manner as the six photoconductors of (Example 2). Then, six types of photoreceptors were sequentially manufactured.

Therefore, the four types of photoreceptors of the present invention are mounted on the image forming apparatus 8, respectively, and toner images are formed on the photoreceptors under the conditions described in (Example 2). The image was transferred to a commercially available plain paper by a transfer roller and heat-fixed to obtain an image.
D. Had an image density of 1.4 or more, no fogging of the background, and a good image with a resolution of 300 DPI.

However, when the two types of photosensitive members of the comparative example were subjected to image evaluation in the same manner as described above, the photoresponsiveness was poor due to the low carrier mobility in the carrier transport layer, and a sufficient potential contrast was not formed. A toner image of a sufficient density is not formed, D. Was an insufficient image with an image density of 0.7.

Further, when the durability of these six types of photoreceptors was evaluated in the same manner as in (Example 3), similar results were obtained, and the photoreceptors of the present invention all had excellent film strength. It was found that the durability was good.

(Example 7) On a peripheral surface of a transparent cylindrical glass substrate (or cylindrical plastic substrate), an ITO layer, which is a light-transmitting conductive layer, is formed to a thickness of 1000 A by an active reaction vapor deposition method. Poly (trimethylphenyldisilane) obtained by dechlorination polymerization of 2,2-dichlorotrimethylphenyldisilane is dissolved in toluene, and a-Si
After being mixed with a solution containing a system powder, the film-formed cylindrical glass substrate was immersed, and then dried with hot air at 100 ° C. As a result, a photoconductor having a single layer was obtained in place of the stacked photoconductor 9.

Mw and Mw / Mw /
When Mn and Hall mobility were measured, respectively
2,000,000, 3, 6 × 10 ⁻⁴ cm ² / V · sec.

Then, this photoreceptor is mounted on the image forming apparatus 8, and a toner image is formed on the photoreceptor in the same manner under the conditions described in (Example 2). The image was transferred and heat-fixed to obtain an image. D. Has an image density of 1.4 or more, has no background fog, and has a resolution of 300 DP.
I was a good image. When the durability of this photoreceptor was evaluated in the same manner as in Example 3, it was found that the photoreceptor had excellent film strength and good durability.

(Example 8) On a peripheral surface of a transparent cylindrical glass substrate (or cylindrical plastic substrate), an ITO layer, which is a light-transmitting conductive layer, is formed to a thickness of 1000 A by an active reaction vapor deposition method. Poly (trimethylphenyldisilane) obtained by dechlorination polymerization of 2,2-dichlorotrimethylphenyldisilane is dissolved in toluene, and
After mixing with the solution containing the c powder dispersed and contained by the ultrasonic dispersion method, the film-formed cylindrical glass substrate is immersed,
Then, it dried with 100 degreeC hot air. As a result, a photoconductor having a single layer was obtained in place of the stacked photoconductor 9.

The Mw and Mw / Mw of the polysilane layer of this photoreceptor were
When Mn and Hall mobility were measured, respectively
1,700,000 and 3,6 × 10 ⁻⁴ cm ² / V · sec.

Then, this photoreceptor is mounted on the image forming apparatus 8 and a toner image is formed on the photoreceptor in the same manner under the conditions described in (Example 2), and the toner image is transferred to a commercially available plain paper by a transfer roller. The image was transferred and heat-fixed to obtain an image. D. Has an image density of 1.4 or more, has no background fog, and has a resolution of 300 DP.
I was a good image. When the durability of this photoreceptor was evaluated in the same manner as in Example 3, it was found that the photoreceptor had excellent film strength and good durability.

(Example 9) Next, in this example, an organic photoconductive material made of titanyl phthalocyanine was formed as a photocarrier excitation layer 12 on the peripheral surface of an Al cylindrical body in the same manner as in (Example 2). Similarly to the four types of photoreceptors of the present invention described in (Example 2) above, the four types of polysilane compounds (a-1, b-1, b-2, and c) of (Example 1) were used. A polysilane-based carrier transport layer 13 having a thickness of 5 μm was formed, and each photoconductor was manufactured.

The four types of polysilane photoreceptors thus obtained were charged using a corona charger to which a voltage of -6 kV was applied, and the surface potential of the dark area was measured to determine the initial charging potential. It showed a potential, and it was confirmed that it had high charging ability.

Next, after the surface potential was charged to -800 V, light having a wavelength of 650 nm was irradiated to reduce the surface potential to -5V.
The exposure energy (half-exposure amount) required to attenuate the voltage from 00 V to -250 V was measured, and the half-life was determined by its reciprocal. The half-life was 2.0 (cm ² / μJ), indicating high light sensitivity. Was.

Further, when the spectral sensitivity characteristics were examined by changing the exposure wavelength, it was found that the reciprocal of the half-reduced exposure amount was 2.0 (cm ² / μJ) or more over the range of 600 to 800 nm, indicating that the spectral sensitivity characteristics were excellent. Had.

Further, when an exposure amount twice as large as the above-mentioned half-exposure amount was given and the surface potential at that time was determined as a residual potential, it was as low as 10 V or less, showing excellent characteristics.

Next, these photosensitive members are mounted on a printer (image forming apparatus 30) according to the Carlson method having the structure shown in FIG.
An image was formed using a pi (dot / inch) dynamic drive type LED head, and the image was evaluated for image density, resolution, back fog, and afterimage (ghost). As a result, the image density was O.D. D. Was 1.4, the resolution was good at 400 dpi, there was no fogging of the back, no afterimage was observed, and the rotation speed of the drum-shaped photosensitive member was increased. Further, even when image formation was continuously performed on 10,000 sheets, no change in image quality such as a decrease in image density or resolution or an increase in fog of the back was observed, and it was confirmed that the image had excellent durability. .

(Example 10) Each photoconductor of (Example 9) is mounted on a commercially available copying machine according to the Carlson method, and an image is similarly formed using an optical system for irradiating the photoconductor with light reflected from a document as an exposure means. After forming, an image having excellent image quality in all of image density, resolution, back fog, gradation reproducibility, and afterimage was obtained, and the rotation speed of the drum-shaped photoreceptor was increased. It was confirmed that the photosensitive member had excellent characteristics. It should be noted that the present invention is not limited to the above-described embodiment, and improvements and modifications may be made without departing from the scope of the present invention.

[0105]

As described above, the polysilane compound for a photoreceptor of the present invention has a weight average molecular weight Mw of the polysilane compound of 50,000 to 2,500,000 and a ratio of 10 or less as compared with the number average molecular weight Mn. Thus, a hole mobility of 10 ⁻⁵ cm ² / V · sec or more was obtained.

According to the present invention, a photoconductor containing a polysilane compound having high hole mobility can be stably provided by forming a carrier transport layer from the polysilane compound. Moreover, if Mw is increased and the molecular weight distribution is set in a narrow range, the strength of the photosensitive layer can be significantly increased.
A highly reliable photoreceptor with excellent durability was provided.

Further, in the present invention, a desired polysilane compound can be easily produced by setting Mw and Mn, and a high-quality photoreceptor can be stably manufactured. There is an advantage that the yield is improved, and as a result, the manufacturing cost is reduced.

Furthermore, the photoreceptor of the present invention could be suitably mounted on an image forming apparatus requiring high carrier mobility, for example, an image forming apparatus of a light back exposure type.

Further, according to the image forming apparatus of the present invention, the carrier generated inside the photosensitive layer by the light irradiation of the exposure means moves at a high speed inside the layer, so that the time for forming the electrostatic latent image is reduced. Accordingly, the rotation speed of the drum can be increased if the photosensitive member is in the form of a drum, and the image formation can be performed at a high speed. In addition, even in the charge removal by exposure after transfer, the carrier generated inside the photosensitive layer quickly contributes to charge removal, so the area of the photosensitive layer required for charge removal is narrowed, and the drum shape is increased in conjunction with the higher speed of the photosensitive drum. Thus, the diameter of the photoconductor can be reduced, and the size of the image forming apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a photoconductor according to the present invention.

FIG. 2 is a cross-sectional view of a photoconductor according to the present invention.

FIG. 3 is a schematic view illustrating an electrophotographic method used in Examples.

FIG. 4 is a main part configuration diagram of an electrophotographic method used in Examples.

FIG. 5 is a schematic configuration diagram of an image forming apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive substrate 2 laminated photosensitive layer 3 photocarrier excitation layer 4 carrier transport layer 5 carrier transporter 6 photocarrier exciter 7 single photosensitive layer

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Ozawa 704-19, Matabe, Noshino, Tamashino-machi, Tamaki-cho, Mie Prefecture Inside the Mie Plant of Kyocera Corporation JP-A-3-245169 (JP, A) JP-A-61-170747 (JP, A) JP-A-3-109560 (JP, A) JP-A-2-109054 (JP, A) JP-A-63-264759 (JP, a) JP Akira 59-191043 (JP, a) JP flat 3-11353 (JP, a) JP flat 1-293349 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) G03G 5/00

Claims (5)

(57) [Claims] A weight average molecular weight represented by the following chemical formula 1 is 5:
0,000-2,500,000 and 10 in comparison to the number average molecular weight
A polysilane compound having the following ratio , wherein R _{1 to} R ₆
Is formed as an aryl group to form a hole mobility
To at least 10 ^-5 cm ² / V · sec.
Position that is not so far as dimer sites are formed
Polysilane compound for photoreceptor arranged in Embedded image 2. A photoreceptor containing a polysilane compound, wherein a photosensitive layer is formed by laminating a photocarrier excitation layer and a carrier transport layer comprising the polysilane compound of claim 1 on a conductive substrate. 3. The photoconductor according to claim 2, wherein a particulate photocarrier exciter is added to the carrier transporter comprising the polysilane compound according to claim 1 instead of the photoconductive layer having a photocarrier excitation layer and a carrier transport layer. A photosensitive member containing a polysilane compound, wherein a photosensitive layer comprising the same is formed. 4. A photosensitive member according to claim 2, wherein said developing member is provided on a photosensitive layer side of said photosensitive member, and an exposing means irradiates image exposure light from a conductive substrate having a light-transmitting property. And a device for irradiating image exposure light from the exposure unit while applying a voltage between the developing unit and the conductive substrate to form a toner image on the surface of the photoreceptor. Image forming device. 5. The photoconductor of claim 2 or 3, a charging device for applying a charge to the surface of the photoconductor, and an exposure device for irradiating a charged area of the photoconductor with light. Developing means for forming an electrostatic latent image on the surface of the photoreceptor by means and exposure means, and forming a toner image corresponding to the electrostatic latent image on the surface of the photoreceptor; An image forming apparatus comprising: a transfer unit for transferring; a cleaning unit for removing residual toner on the surface of the photoconductor after the transfer; and a charge removing unit for removing a residual electrostatic latent image after the transfer.