JPH0962070A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high hole mobility by incorporating a specified amt. of polysilane into a carrier transfer layer of a photoreceptor. SOLUTION: The laminar type photosensitive layer formed on a conductive substrate consists of a photocarrier exciting layer and a carrier transfer layer containing 0.1-5.0wt.% polysilane expressed by formula. In formula, R1 -R4 are hydrogen atom, alkyl groups, etc., x-z are 0 or 1 to represent whether each unit is present or not, (n) is a polymn. degree. In the image forming zone, a rotating photoreceptor is irradiated with light from a LED head through a light-transmitting supporting side for image exposure to produce holes and electrons in the inside of a photocarrier exciting layer. When positive bias voltage is applied on a developing device, electrons move to the surface side of the carrier transfer layer by the bias voltage and are compensated with the positive charge on the edge of a magnetic brush to deposit the toner on the surface of the photoreceptor. Further, the toner is transferred to a recording paper by a transfer roller and then fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is equipped with a photoconductor containing a polysilane compound comprising a novel polysilane compound having a high hole mobility, and the photoconductor containing the polysilane compound is applied to an optical back exposure method. The present invention relates to an image forming apparatus in which each of the two is disposed on both sides of the transfer material.

[0002]

2. Description of the Related Art Poly-N-vinylcarbazole (PVK) is used as a material for a carrier transport layer of an electrophotographic photoreceptor.
Polymeric materials such as are used recently, but in order to meet the demand for high mobility carriers, low molecular compounds such as arylamine derivatives and hydrazone derivatives have recently been dispersed in an inert polymer binder such as polycarbonate resin. Molecular resin dispersed composite materials have been proposed.

However, the recent demand for high carrier mobility for the material for the carrier transport layer is not yet satisfactory, and higher carrier mobility,
Particularly high 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 (see JP-A-2-133416 and JP-A-2-294654). JP-A-2-133416
JP-A-2-294654 proposes a hole-transporting substance composed of a block copolymer of a polymer block A made of polysilane and a block B made of a polymer of an anionically polymerizable monomer. A light-receiving layer containing is proposed.

However, according to the former proposal, the number average degree of polymerization of the polysilane of the polymer block A is 10 to 50000.
The latter proposal has a weight average molecular weight of 6,0.
Although it is described that it is from 00 to 200,000,
No mention is made 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-Siσ bond as the main chain and having two kinds of organic substituents as shown in the chemical formula shown in Chemical formula 2, and depending on the degree of polymerization, a compound having a low degree of polymerization is highly polymerized. Various polymers can be produced up to various compounds, and various polymers can be produced by combining the weight average molecular weight and the number average molecular weight, but there is no description of the conditions for these combinations. Moreover, it should be noted that there are copolymers (copolymers) of monomers having the chemical formula shown in Chemical formula 2, and the combination thereof is further increased.

[0007]

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The present inventor has made an earnest study paying attention to this degree of polymerization, and as a result of repeating many experiments, this degree of polymerization is related to the hole mobility and the film strength. Although related, it was found that the hole mobility and the film strength are improved by reducing the compound having a low polymerization degree.

Based on the above findings, the present inventor has been able to provide a polysilane compound-containing photosensitive member which has improved hole mobility and film strength (durability) and is excellent in reliability (Japanese Patent Application No. Hei 5 (1999) -135242).
-216582).

On the other hand, the inventor of the present invention divides an upper main body and a lower main body along a recording material conveyance path and provides a toner image generating means using a conductive toner for each of them. Method printer, facsimile,
In a copying machine, an image forming apparatus has also been proposed, which is provided with transfer means for transferring a toner image generated by each toner image generating means onto a recording material and can transfer the toner image on both sides thereof (see Japanese Patent Laid-Open No. 4-307575). ).

According to the above proposal, the toner can be stably conveyed without disturbing the image, and the toner image generating means can be constituted by the back exposure device having the exposing means inserted in the photoconductor. A more compact image forming apparatus can be provided.

[0012]

However, according to the proposed image forming apparatus, since two toner image generating means are provided in the same apparatus along the recording material conveying path,
Even if it is aimed at downsizing, there is a problem that it is inevitable that the size of the image forming apparatus becomes larger than that of an existing image forming apparatus provided with one toner image generating unit.

As a result of intensive studies conducted by the inventor in view of the above circumstances, according to the polysilane compound-containing photoreceptor proposed by the inventor in Japanese Patent Application No. 6-90136, the hole mobility and the film strength ( It has been found that when the photoconductor is mounted on the image forming apparatus as described above, the diameter of the diameter of the photoconductor can be reduced, and accordingly, the image forming apparatus itself can be downsized.

Therefore, the present invention has been completed based on the above findings, and an object thereof is to dispose image forming portions made of a photoconductor containing a polysilane compound on both sides of a material to be transferred (recording material), thereby forming an image forming apparatus. There is a further miniaturization.

Another object of the present invention is to provide a high-performance and high-reliability image forming apparatus capable of obtaining an image having excellent optical density, no fog on the back, and good resolution. is there.

[0016]

In the image forming apparatus of the present invention, a photocarrier excitation layer is formed on a transparent conductive substrate, and a polysilane compound represented by the following chemical formula 1 is used as a carrier transport material. An exposing means for irradiating the conductive substrate side of the polysilane compound-containing photoconductor having a photosensitive layer formed by laminating a carrier transport layer containing 1 to 5.0% by weight with image exposure light, and a developing means for the photosensitive layer side. And a voltage applying means for applying a voltage between the developing means and the conductive substrate, and an image is formed from the exposing means while applying a voltage by the voltage applying means to form a toner image on the surface of the photoreceptor. An image forming unit including a mechanism for irradiating exposure light and a transfer unit for transferring the toner image onto the transfer material is arranged on both sides of the transfer material.

[0017]

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In another image forming apparatus of the present invention, in the image forming apparatus of the present invention, the carrier transporting material is replaced by a polysilane compound of 0.1 to 0.1 in place of the polysilane compound-containing photoreceptor. It is a photoconductor containing a polysilane compound, which is formed by forming a photosensitive layer containing 5.0% by weight and containing a photocarrier generating substance on a transparent conductive substrate.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(Structure of Polysilane Compound) R _{1 to} R ₆ of the polysilane compound shown in 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,
There are substituted alkoxy groups. Examples of the alkyl group, aryl group and alkoxy group include methyl, ethyl,
Examples thereof include propyl, butyl, amyl, hexyl, octyl, nonyl, decyl, pentadecyl, stearyl, cyclohexyl, phenyl, tolyl, xylyl, naphthyl, methoxy and ethoxy. Further, 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 in order to represent 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
It may be a copolymer of the polysilane compound of Chemical formula 1 as shown in. According to Formula 3, x, y, z, x ′,
By selectively setting y ′ and z ′ to 0 or 1, various combinations can be made depending on the presence or absence of each unit. That is, a polymer composed of three types of units of monomers and 3
A compound with a polymer consisting of three types of units of monomers, a polymer consisting of three types of units of monomers and 2
Compounds with polymers consisting of monomers of three types of units, Polymers consisting of monomers of three types of units and 1
Compounds with polymers consisting of monomers of two types of units, Polymers consisting of monomers of two types of units and two
A compound with a polymer consisting of two types of units of monomers, a polymer consisting of two types of units of monomers and 1
Compounds with polymers consisting of monomers of one kind unit, polymers with monomers consisting of one kind of unit and one
There are compounds with polymers that consist of monomers of a class of units. Further, there are compounds obtained by combining these compounds.

[0022]

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The polysilane compound of the present invention has various monomers as described above, but among others, when intensive research was conducted on the molecular structures of some of the monomers, the reason why high hole mobility was obtained was that It was discovered that it is necessary to prevent structural hole traps by not forming dimer sites due to aromatic rings.

That is, the present inventor has 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 a function of increasing the activation energy E _0. And E _{0 of} the aromatic substituent existing on the adjacent Si is 0.34 to 0.36 eV,
When E _{0 of the} aliphatic substituent is 0.22 eV and the aromatic ring has an aromatic substituent at every other Si atom and the structural regularity is high, E
It is confirmed that ₀ is 0.26 eV, and this E ₀
Is an index indicating the trap depth of the Poole-Frenkel type hopping conduction. According to the experiment conducted by the present inventor, the increase of E ₀ due to the presence of the aryl group is due to the adjacent aromatic ring. It was found that the cause was the formation of dimer sites.

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

(Structure of Photoreceptor) FIGS. 1 and 2 show the basic layer structure of the photoreceptor according to the present invention. FIG. 1 shows a conductive substrate 1.
This is an example in which a laminated type photosensitive layer 2 is formed on top of the photosensitive layer 2.
The carrier transport layer 4 containing 0% by weight, and the layers 3 and 4 may be laminated in different orders. FIG.
Is a single photosensitive layer 7 comprising a carrier transporter 5 containing 0.1 to 5.0% by weight of polysilane and a granular photocarrier exciter 6.

The conductive substrate 1 has a structure in which a transparent conductive layer is formed on a transparent insulating substrate. For example, there is one in which a conductive thin film is coated on the surface of an insulating material such as transparent glass or ceramic. The substrate 1 may be a sheet-shaped, belt-shaped or web-shaped flexible conductive sheet,
Such sheets include metal sheets such as SUS, Al and Ni, or metal such as Al and Ni or tin oxide, indium tin oxide (IT) on a polymer resin film such as polyester, nylon and polyimide.
A transparent conductive material such as O) or an organic conductive material coated by vapor deposition or the like and subjected to conductive treatment is used.

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 materials having high carrier generation efficiency using, for example, titanyl phthalocyanine, metal phthalocyanine pigments, metal-free phthalocyanines, perylene pigments, polycyclic quinone pigments, squarylium dyes, azurenium dyes, thiapyrylium dyes, and trisazo pigments as organic photoconductive materials. Optical semiconductors are selected.
If it is 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. Then, in the case of 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,
The RF magnetron sputtering method, the DC magnetron sputtering method, the thermal CVD method, the plasma CVD method or the like is used.

When the photocarrier excitation layer 3 is formed of a-Si, carbon, nitrogen, oxygen and germanium are added thereto to make it amorphous and SiC.
It may be a layer of N, SiO, or SiGe. Further, by forming a layer containing an element such as B or P, which is an impurity element for controlling the conductivity type, it is possible to provide a function such as a carrier injection blocking layer.

For the photosensitive layer 7, when an a-Si-based powder is used as the granular photocarrier excitation body 6, this powder can be produced in the same manner as the a-Si-based photocarrier excitation layer 2 and is granular. , Columnar, spherical, and flake-shaped. Its diameter may be 0.05 to 5 μm, preferably 0.1 to 3 μm, and the powder may be contained in the layer in an amount of 1 to 80% by weight, preferably 5 to 60% by weight. When it is contained, it is dispersed by a stirring method, an ultrasonic dispersion method, or the like.

In addition, titanyl phthalocyanine (TiO 2
Pc) may be dispersed in polysilane as the photosensitive layer 7, and high sensitivity can be obtained particularly for image exposure on the long wavelength side. This TiOPc is a raw material T
The iOPc pigment is subjected to a purification treatment such as sublimation purification or purification with an acid or an alkali, and is kneaded with various dispersers together with a grinding aid, a solvent or the like, or is recovered in the form of fine particles by a steam method. The particles are adjusted into particles and 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 photoconductor according to the present invention may be further improved or changed in accordance with the required electrophotographic characteristics based on the above-mentioned basic structure. For example, by providing an intermediate layer between the substrate 1 and the photosensitive layers 2 and 7 on the substrate 1, the charging property can be enhanced 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 thereof.

(Method of Forming Polysilane-Containing Layer) For the carrier transport layer 4 and the photosensitive layer 7 which are polysilane-containing layers, for example, polysilane is dissolved in an organic solvent, and the solution is prepared by bar coating, dipping, melt extrusion or spraying. It is formed by coating and drying by a coating method such as a coating method. In this organic solvent,
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, halogens, halogenated hydrocarbons and the like are used, and one kind or a mixture of two or more kinds thereof is used.

Further, a solution prepared by mixing a low-molecular-weight carrier-transporting substance, polysilane, and a binder resin in the above organic solvent is prepared, and the substrate for coating is dipped in this solution and then dried to form a layer. Good. Examples of the low-molecular-weight carrier transport material include phenylenediamine compounds, oxadiazole compounds, styryl compounds, pyrazoline compounds, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds,
There are nitrogen-containing cyclic compounds such as isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds and triazole compounds, and condensed polycyclic compounds.

With respect to these low-molecular-weight carrier-transporting substances, polysilane is contained in an amount of 0.1 to 5.0% by weight, preferably 0.1.
It is advisable to contain the compound in an amount of 1 to 2.0% by weight. Within this range, the carrier transporting function is enhanced, the photosensitivity and the residual potential are predominantly acted, and the charging ability is relatively increased. The characteristics are improved. Moreover, since there is no particular limitation on the molecular weight and the molecular weight distribution of polysilane, a large amount of polysilane used for this photoreceptor can be supplied at low cost.

Furthermore, polysilane having a high molecular weight of more than 2,500,000 and a narrow molecular weight distribution (the film strength is high,
Solubility in a solvent is not good), and polysilane having good solubility may be used.
A layer can be easily formed by a coating method or the like. In addition, a desired film strength can be obtained by appropriately selecting the binder resin containing polysilane.

Examples of the binder resin include polystyrene, polyvinyl chloride, polypropylene, polyamide, polyimide, polyester, polyether, polyurethane, epoxy resin, polycarbonate, polyacrylate, polyarylate, silicone resin and polyvinyl butyral. These resins are used alone or in combination of two or more. Further, except for a resin having a very high transparency such as a methacrylate resin, most of the resin itself absorbs ultraviolet rays, and these resins can prevent deterioration of polysilane due to ultraviolet rays.

(Light Back Exposure Method) Next, the light back exposure method of the image forming apparatus (printer) of the present invention will be described in detail. FIG. 3 is a schematic diagram showing the image forming unit 8 of the light back exposure type, which is an electrophotographic image forming apparatus combined so that exposure and development can be performed almost simultaneously without the need for corona charging. In the figure, 9 is a transparent conductive layer 11 and a photocarrier excitation layer 12 and 10 ^-5 c on a transparent support 10.
Carrier transport layer 13 having a mobility of at least m ² / V · sec
A drum-shaped photosensitive member in which and are stacked, 14 is an LED head as an exposing unit, 15 is a developing device as a developing unit, 1
Reference numeral 6 is a transfer roller as a transfer means. The LED head 14 and the developing device 15 are arranged substantially symmetrically with a part of the photoconductor 9 interposed therebetween. As such an LED head 14, a small and low power consumption dynamic drive type LED 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 (the light source 17 for erase is not always necessary). In the developing device 15,
For example, a one-component magnetic conductive toner as a developer, which is composed of a cylindrical magnetic pole roller 18 having eight poles and a cylindrical conductive sleeve 19 arranged around the outer circumference of the magnetic pole roller 18, is further stored in a toner receiver 20. Alternatively, the two-component developer including the conductive magnetic carrier and the insulating toner is delivered to the outer circumference of the sleeve 19 to form the magnetic brush 21. A bias power source 22 is provided between the sleeve 19 and the transparent conductive layer 11, and a + or − voltage (300 V or less) is applied between the bias power source 22 and the transparent conductive layer 11 depending on the potential characteristics of the photoconductor 9. Apply. 23 is a toner image formed on the surface of the photoconductor 9;
Is a recording paper as a material to be transferred, and 25 is a residual toner after the transfer. In addition to this, rotation driving means for the developing device and rotation means for the photoconductor 9 are provided. It should be noted that the exposure unit 14 has an L
Although the ED head is used, a laser, a liquid crystal shutter, an EL head or the like may be used. As the erase light source 17, a light source such as a halogen lamp, a fluorescent lamp, and an EL array can be used in addition to the LED array.

Thus, according to the image forming section 8 having the above-described structure, the LED is mounted on the rotating photosensitive member 9 from the transparent support 10 side.
When light for image exposure is irradiated from the head 14 to generate holes and electrons inside the photocarrier excitation layer 12, when a + bias voltage is applied to the developing device side, the electrons are caused by the bias voltage to the carrier transport layer 13 Of the magnetic brush 21 and the positive charges at the ends of the magnetic brush 21 to cancel each other out, 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 unit 8 having the above-mentioned structure will be described in more detail with reference to FIG. FIG. 4 is an explanatory diagram showing a developer pool 26 formed by a part of the photoconductor 9 and the developing device 15. The developing device 15 for holding the developer includes a conductive sleeve 19 and a magnetic pole roller 1 arranged inside the sleeve.
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.

When the developer is conveyed in the direction opposite to that of the photoconductor 9, the friction between the two causes the developer to reach the downstream side (the side where the photoconductor is separated from the developer) of the closest position between the developing device 15 and the photoconductor 9. A pool 26 is created. That is, the portion of the developer pool 26 that extends beyond the original height of the developer is the developer pool 26. The developer transport speed, the height of the developer, and the gap between the sleeve 19 and the surface of the photoconductor 9 are different from each other. Is appropriately set according to the rotation speed of the toner and the required size of the developer pool 26.

Reference numeral 27 is 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 a magnetic brush 21 and a developer pool 26, and may be a one-component developer as long as it has necessary conductivity, and a conductive carrier. It is also possible to use a two-component developer in which a conductive material and an insulating toner are mixed at a predetermined mixing ratio so as to have a required electric conductivity.

The position for image exposure is not the closest position A between the surface of the photoconductor 9 and the developing sleeve 19, but the position B of the developer pool 26 formed on the downstream side by the reverse rotation of the photoconductor 9, Preferably, it is located in the downstream half of the developer pool 26. 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 toner image 23 is formed, the photoconductor 9 quickly separates from the developer pool 26, so that the toner image 23 on the surface of the photoconductor 9 is disturbed by a 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 pool 26, as compared with the position A where the surface of the photosensitive member 9 and the developing sleeve 19 are closest to each other,
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 to have a common potential with the translucent conductive layer 11. Alternatively, the potential is set lower or higher than the potential of the sleeve 19.

As described above, when the control electrode 27 capable of applying a potential independently of the sleeve 19 is provided, the surface potential of the photoconductor 9 is neutralized via the developer, or the surface potential of the photoconductor 9 is made uniform. It is possible to cancel the influence of the history of the photoconductor 9 due to the presence or absence of charging or exposure 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 adjust and obtain the optimum image forming conditions for the image density, the background fog, and the like. In addition, the control electrode 2
By increasing the potential of No. 7 and lowering the potential of the sleeve 19, so-called reversal development, in which toner adheres to the non-exposed area and toner does not adhere to the exposed area, is also possible.

Toner image 23 formed on the surface of photoreceptor 9
Is then transferred to the recording paper 24 and fixed to form a recorded image, and the residual toner 25 remaining on the surface of the photoconductor 9 without being transferred is recovered and reused by the developing device 15 in the next image forming process. .

Further, 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 charges trapped on the surface of the carrier transport layer 13 of the photoconductor 9 are 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.

Further, the carrier transport layer 13 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 polysilane compound of the present invention is characterized in that the surface is hard and has an appropriate slip property, and it is excellent in abrasion resistance and printing durability, and has good 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 the experiments repeated by the present inventor,
When the polysilane-based carrier transport layer 13 according to the present invention was formed, the hardness of its surface was a Rockwell hardness of M60 or more. Moreover, the relative permittivity thereof becomes 3 or less, and the repeating durability and the responsiveness of charging and erasing become suitable.

(Image Forming Apparatus) Next, the image forming apparatus of the present invention will be described with reference to FIG. This figure is a configuration diagram of the main parts of the image forming apparatus 30. In this image forming apparatus 30,
The image forming units 8 are arranged on both sides of the recording paper 24. With this structure, the recording paper 24 moves in the direction of the arrow, and the photoconductors that rotate in both image forming units 8 are rotated. The LED head 14 irradiates the image exposure light 9 with light, and holes and electrons are generated thereby, so that toner is attached to the surface of the photoconductor 9. Then, the toner is transferred onto the recording paper 24 by the transfer roller 16,
Then, the process of fixing is performed.

Thus, according to the image forming apparatus 30 having the above-described structure, printing can be performed on both sides of the recording paper 24 at the same time by feeding the recording paper 24 once. Since the body is mounted, the rotation speed of the drum-shaped photoreceptor 9 can be increased, and the image formation can be performed at high speed. Moreover, even in the charge removal by the exposure after the transfer, the carriers generated inside the photosensitive layer immediately contribute to the charge removal,
The area of the photosensitive layer required for the charge removal is narrowed, and the speed of the photosensitive drum is increased, so that the diameter of the drum-shaped photosensitive member can be reduced and the image forming apparatus can be downsized.

Further, in the image forming apparatus 30 having the above structure, the developer is composed of the combination of the insulating toner and the conductive carrier, so that the image forming apparatus 30 is disclosed in JP-A-4-30757.
Compared with the image forming apparatus proposed in Japanese Patent No. 5 publication, the toner image conveying means is not necessary, and the image forming apparatus 30 can be further downsized.

[0056]

【Example】

(Example 1) In this example, polysilane was synthesized as follows. First, 89.1 g (3.88 mol) of sodium was added to 1.25 liter of toluene which was a solvent, and the mixture was heated under reflux to form a sodium dispersion. On the other hand, 250 ml (1.55 mol) of phenylmethyldichlorosilane as a starting material was prepared, and 12.5 ml (5% of the total amount) of the phenylmethyldichlorosilane was added dropwise to the sodium dispersion. Let it cool naturally, about 6
When the temperature reached 5 ° C, the remaining phenylmethyldichlorosilane was slowly added dropwise to carry out a polymerization reaction while maintaining the temperature at 65 ° C.

The weight average molecular weight Mw and number average molecular weight Mn of the polysilane obtained by this reaction were measured to obtain Mw /
When Mn was also calculated, Mw was about 30,000, and M
w / Mn was about 4. The yield of polysilane is 1
It was 12 g, and the yield was 60%.

The respective average molecular weights Mw and Mn are measured by gel permeation chromatography, and columns for that purpose are Asahipak GS-310 and GS-51.
0, GSM-700, tetrahydrofuran (THF) was used as a mobile phase, and the resulting effluent was UV.
It was measured with a detector having an absorption of 254 nm. The chromatographic waveform processing was performed using waveform processing software called a chromatographic coder.

(Example 2) According to the polysilane synthesis method of this example, first, sodium 7 was added to 1.25 liters of toluene.
8.4 g (3.41 mol) and copper iodide 2.95 g (1
(5.5 mol) was added and the mixture was heated under reflux. 250 ml (1.55 mol) of dichlorosilane as a starting material was added dropwise to the mixture to carry out a polymerization reaction.

The weight average molecular weight Mw and the number average molecular weight Mn of the polysilane obtained by this reaction were measured in the same manner,
When Mw / Mn was also calculated, Mw was about 90,000 and Mw / Mn was about 10. The yield of polysilane was 92 g, which was 49.4%.

(Example 3) Next, as a transparent conductive layer 11, I was formed on the peripheral surface of a transparent cylindrical glass substrate or plastic.
A TO layer is formed to a thickness of 1,000 A by an active reaction vapor deposition method, and then a titanyl phthalocyanine (TiO 2 layer is formed thereon.
Pc) and polyvinyl butyral are immersed in a liquid obtained by dispersing and mixing them in chloroform, and then dried at 55 ° C. under reduced pressure to form a 3 μm thick photocarrier excitation layer 1 made of TiOPc.
Formed 2. Next, on this film-forming cylindrical glass substrate,
20 μm of a carrier transport layer 13 formed by mixing 1% by weight of polysilane of (Example 1) or (Example 2) with 4- (diethylamino) benzaldehyde diphenylhydrazone (hereinafter abbreviated as DEH) that is a carrier transport substance
To have thicknesses of A and A, respectively, to prepare photoconductors A-1 and A-2.

More specifically, the method for forming the carrier transport layer 13 will be described. Using bisphenol A polymer as the binder resin and DEH as the carrier transport material, these and the polysilane of (Example 1) or (Example 2) are used. Cylindrical film-forming shape in which a solution containing 1% by weight with respect to the carrier transporting substance and dissolved in toluene together with 50% by weight of a binder resin was prepared, and the photocarrier excitation layer 12 was formed in this solution. Dip the glass substrate, then 10
It dried with the hot air of 0 degreeC. Thus, a photoconductor A-1 containing the polysilane of (Example 1) and a photoconductor A-2 containing the polysilane of (Example 2) were produced.

When the carrier transport layer 13 was formed on the film-formed cylindrical glass substrate on which the photocarrier excitation layer 12 was formed, polysilane was not contained and the other structures were the same, and the carrier transport layer having a thickness of 20 μm was formed. Was formed, and this was used as a photoconductor B of a comparative example.

Therefore, the photoconductors of the present invention A-1, A
-2, and the photoconductor B of the comparative example are mounted on the image forming unit 8 as shown in FIG. 3, respectively, and a two-component developer including a conductive magnetic carrier and an insulating toner is used as the developer. A dynamic drive type LED head (resolution 300 DPI (dots / inch)) is arranged, and Vs = −200 between the sleeve 19 and the translucent conductive layer 11.
A voltage of V is applied, image exposure is performed at a wavelength of 660 nm,
Toner image is formed on the photoconductor and the toner image is +400
An image was obtained by transferring to commercial plain paper by a transfer roller to which a transfer bias voltage of V was applied and heat fixing. The developer was rotated in the direction opposite to that of the photoconductor 9 to form the developer pool 26, and the area was exposed.

When this image was evaluated, the photoconductor A-
Regarding Nos. 1 and A-2, the optical densities (hereinafter referred to as OD) had image densities of 1.4 or more, there was no background fog, and the resolution was a good image of 300 DPI.

However, when the image of the photosensitive member B of the comparative example was evaluated in the same manner as described above, the photoresponsiveness was poor because the carrier mobility in the carrier transporting layer was low, and sufficient potential contrast was not formed. A toner image of high density is not formed, and D. Was 0.6 and the image was inadequate.

(Example 4) In this example, the durability of the three types of photoreceptors of (Example 3) was evaluated using the image forming section 8 as shown in FIG. When 10,000 sheets were printed in the image forming section 8 equipped with the respective photoconductors and the subsequent images were evaluated and compared with the initial image, the results of the O.O. D. Has an image density of 1.4 or more, has no background fog, and has a resolution of 300 DPI, and both images have excellent durability.

Example 5 A transparent conductive layer 11 is formed on the peripheral surface of a transparent cylindrical glass substrate (or a cylindrical plastic substrate).
As an ITO layer with a thickness of 1,000 A by active reaction vapor deposition, and then mounted in a glow discharge decomposition apparatus,
After completely evacuating the inside of the reaction vessel, first apply a discharge voltage while flowing SiH ₄ gas and B ₂ H ₆ gas at a fixed ratio to prevent injection of a-Si ・ B ・ H carrier with a thickness of 0.5 μm. Layers were formed. After that, the injection of B ₂ H ₆ gas was stopped and S
The iH ₄ gas was controlled at a constant flow rate to form the photocarrier excitation layer 12 having a thickness of 2 μm. Next, on this film-forming cylindrical glass substrate, two types of 5 μm-thick polysilane-based carrier transport layers 13 corresponding to the polysilane compound were formed in the same manner as the three types of photoconductors of (Example 3), and the photoconductor A-1 was formed. , A-2 corresponding to A, A-2, and a comparative photoreceptor B = 1.

Therefore, the photoconductor of the present invention is A = 1, A
No. 2 is mounted on the image forming section 8 as shown in FIG. 3, a toner image is formed on the photoconductor under the conditions described in (Example 3), and the toner image is commercially available by a transfer roller. The image was transferred to paper and heat-fixed to obtain an image.

When this image was evaluated, no matter what kind of photoreceptor was used, it was found that the image quality was 0. D. Has an image density of 1.4 or higher,
There was no background fogging and the image was a good image with a resolution of 300 DPI.

However, the photosensitive member B = the photosensitive member of the comparative example.
When 1 was image-evaluated in the same manner as described above, the photoresponsiveness was poor due to the low carrier mobility in the carrier-transporting layer, and a sufficient potential contrast was not formed, so that a toner image of sufficient density was not formed, and ． D. Was 0.7 and the image was insufficient.

(Example 6) In this example, the durability of the two kinds of photoconductors A = 1 and A = 2 in (Example 5) was evaluated in the same manner as in (Example 4), and similar results were obtained. It was found that both of them had excellent film strength and good durability.

Example 7 An ITO layer, which is a translucent conductive layer, is formed on the peripheral surface of a transparent cylindrical glass substrate (or a cylindrical plastic substrate) to a thickness of 1,000 A by an active reaction vapor deposition method, and then, Poly (trimethylphenyldisilane) obtained by dechlorination polymerization of 1,2-dichlorotrimethylphenyldisilane is dissolved in toluene, and a
After mixing with a solution containing -Si-based powder, the film-forming cylindrical glass substrate was dipped, and then dried with hot air at 100 ° C. As a result, a single-layer photoconductor was obtained in place of the laminated photoconductor 9.

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

Therefore, this photoconductor is attached to the image forming section 8, a toner image is formed on the photoconductor under the conditions described in (Example 3) in the same manner, and the toner image is transferred to a commercially available plain paper by a transfer roller. When an image was obtained by transfer and heat fixing, no matter what the photoconductor was used, D. Has an image density of 1.4 or more, there is no background fog, and the resolution is 300 DPI.
It was a good image. When the durability of this photosensitive member was evaluated in the same manner as in (Example 4), it was found that the film strength was excellent and the durability was good.

Example 8 An ITO layer, which is a light-transmissive conductive layer, is formed on the peripheral surface of a transparent cylindrical glass substrate (or a cylindrical plastic substrate) to a thickness of 1,000 A by the active reaction vapor deposition method, and then, Poly (trimethylphenyldisilane) obtained by dechlorinating 1,2,2-dichlorotrimethylphenyldisilane is dissolved in toluene, and T
The iOPc powder was dispersed by an ultrasonic dispersion method and mixed with a solution containing the powder, and the cylindrical glass substrate for film formation was immersed therein, and then dried with hot air at 100 ° C. As a result, a single-layer photoconductor was obtained in place of the laminated photoconductor 9.

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

Therefore, this photoconductor is attached to the image forming section 8, a toner image is formed on the photoconductor under the conditions described in (Example 3) in the same manner, and the toner image is transferred to a commercially available plain paper by a transfer roller. When an image was obtained by transfer and heat fixing, no matter what the photoconductor was used, D. Has an image density of 1.4 or more, there is no background fog, and the resolution is 300 DPI.
It was a good image. When the durability of this photosensitive member was evaluated in the same manner as in (Example 4), it was found that the film strength was excellent and the durability was good.

(Example 9) Next, the inventors of the present invention, A-1 and A-2 and B of (Example 3) and A of (Example 5) which are the photoreceptors of the present invention.
= 1, A = 1, B = 1, and the photoconductor of (Example 7) and the photoconductor of (Example 8) according to the present invention, when mounted on the image forming apparatus 30 of FIG. It is possible to print on both sides of the drum simultaneously by feeding 24 times, and it is possible to further increase the rotation speed of the drum-shaped photosensitive member, which makes it possible to increase the speed of image formation. The diameter of the photosensitive member can be reduced, and the image forming apparatus can be downsized.

The present invention is not limited to the above-mentioned embodiments, and within the scope of the present invention,
Improvements and changes can be made.

[0081]

As described above, since the carrier transporting layer of the photoreceptor according to the present invention contains polysilane in an amount of 0.1 to 5.0% by weight based on the carrier transporting material, a high hole mobility can be obtained. As a result, a photoconductor containing a polysilane compound having high hole mobility can be stably provided.

Further, in the present invention, since it is not necessary to particularly limit the molecular weight and the molecular weight distribution of the polysilane, it is possible to easily and stably produce the polysilane as required, whereby a high-quality photoconductor can be stably produced. Since it can be manufactured efficiently, the manufacturing yield is improved, and as a result, the manufacturing cost is reduced.

Furthermore, the photoconductor of the present invention could be suitably mounted in an optical back exposure type image forming apparatus which requires high carrier mobility.

Further, according to the image forming apparatus of the present invention, the carriers generated inside the photosensitive layer by the light irradiation of the exposing means move at a high speed inside the layer, so that the time for forming an electrostatic latent image is increased. Therefore, the rotation speed of the drum-shaped photoconductor can be increased, and the image formation can be performed at 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.

Further, according to the image forming apparatus proposed in Japanese Patent Laid-Open No. 4-307575, the toner image generating means using the conductive toner is provided, and the toner image transferring means indirectly transfers the toner image. However, in contrast to this, by constructing the developer with a combination of an insulating toner and a conductive carrier, it is not necessary to transfer the toner indirectly through the toner image transfer means, and thus the toner The image transfer device is not required, and as a result, the image forming apparatus can be further downsized.

[Brief description of drawings]

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

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

FIG. 3 is a schematic diagram showing an electrophotographic method used in Examples.

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

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

[Explanation of symbols]

 1 Conductive Substrate 2 Laminated Photosensitive Layer 3 Photo Carrier Excitation Layer 4 Carrier Transport Layer 5 Carrier Transport Material 6 Photo Carrier Excitation Body 7 Single Photosensitive Layer 8 Image Forming Section 9 Photosensitive Member 14 LED Head 15 Developer 16 Transfer Roller 24 Recording paper 30 Image forming apparatus

Claims (2)

[Claims] 1. A carrier transport layer containing a photocarrier excitation layer on a transparent conductive substrate and a polysilane compound represented by the following chemical formula 1 in a carrier transport substance in an amount of 0.1 to 5.0% by weight. An exposing means for irradiating image exposing light is provided on the conductive substrate side of the polysilane compound-containing photoreceptor having a photosensitive layer formed by laminating the developing layer and a developing means on the photosensitive layer side, and the developing means and the conductive substrate are provided. And a mechanism for irradiating image exposure light from the exposing means while applying a voltage by the voltage applying means to form a toner image on the surface of the photoreceptor, and a toner applying means for applying a voltage between the toner image and the toner image. An image forming apparatus comprising image forming units each having a transfer unit that transfers the image to a transfer material, and is disposed on both sides of the transfer material. Embedded image 2. The carrier according to claim 1, which contains 0.1 to 5.0% by weight of the polysilane compound represented by the following chemical formula 1 in a carrier transporting material, instead of the polysilane compound-containing photoreceptor, and photocarrier generation is performed. An image forming apparatus, which is a photoconductor containing a polysilane compound, in which a photosensitive layer containing a substance is formed on a transparent conductive substrate. Embedded image