JPH07295264A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Objective] Miniaturization of image forming apparatus [Configuration] A photosensitive layer in which a photocarrier exciter and a polysilane compound are combined is formed on a conductive substrate, and the weight average molecular weight of the polysilane compound is 50,000 ~
2,500,000 and 1 compared to the number average molecular weight
An exposing means for irradiating an image exposure light on the electroconductive substrate side of the polysilane compound-containing photoreceptor having a ratio of 0 or less and a developing means on the photosensitive layer side are provided, and a voltage is applied between the developing means and the electroconductive substrate. 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 photosensitive member, and a means for applying the toner image to the transfer material are provided. An image forming apparatus in which image forming units having transfer means for transferring are arranged on both sides of a material to be transferred.

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 using a novel polysilane compound having an increased hole mobility, and image formation is carried out by applying the photoconductor containing the polysilane compound to a photo back exposure method. The present invention relates to an image forming apparatus in which parts are arranged on both sides of a 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 in the material for the carrier transport layer is not yet satisfied, and higher carrier mobility, especially 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 (Japanese Patent Laid-Open Nos. 2-333416 and 2-2946).
(See No. 54). JP-A-2-133416 proposes a hole-transporting substance composed of a block copolymer of a polymer block A made of polysilane and a block B of a polymer of an anionically polymerizable monomer. In the issue,
Photoreceptive layers containing polysilane compounds have been proposed.

However, in the former publication, the number average degree of polymerization of the polysilane of the polymer block A is 10 to 50,000.
In the latter publication, the weight average molecular weight is 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 is 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]

[Chemical 2]

The present inventor has made an earnest study paying attention to this degree of polymerization, and as a result of repeating many experiments, the 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 inventors provide a polysilane compound for a photoreceptor having an improved hole mobility and a photoreceptor containing a polysilane compound having an improved hole mobility and film strength (durability) and excellent reliability. It was possible (Japanese Patent Application No. 5)
-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 conveying path and provides a toner image generating means using a conductive toner for each of them.
In an image forming apparatus used for an electrophotographic printer, a facsimile, a copying machine, etc., a transfer unit for transferring the toner image generated by each toner image generation unit to a recording material is provided, and the toner image can be transferred on both sides of the transfer unit. An image forming apparatus has been proposed (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 exposure means inserted in the photoconductor. Therefore, a more compact image forming apparatus can be provided.

[0012]

However, according to the image forming apparatus proposed above, two toner image generating means are provided along the recording material conveying path in the same apparatus, so that the image forming apparatus can be made compact. Even if it is aimed, compared to the existing image forming apparatus provided with one toner image generating means, there is a problem that it tends to become large in size.

The present inventor has conducted extensive studies in view of the above circumstances, and as a result, according to the polysilane compound-containing photoreceptor proposed by the present inventor in Japanese Patent Application No. 5-216582, 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 provided with the toner image generating means on both surfaces of a transfer material (recording material).
This is to further reduce the size of the image forming apparatus.

Another object of the present invention is to provide an image forming apparatus having high performance and high reliability.

[0016]

In the image forming apparatus of claim 1, an exposing means for irradiating an image exposing light to the conductive substrate side of the polysilane compound-containing photoconductor of the following (A) or (B) is used. A developing means is provided on the photosensitive layer side, a voltage applying means for applying a voltage is provided between the developing means and the conductive substrate, and a voltage is applied by the voltage applying means to form a toner image on the surface of the photoreceptor. However, an image forming unit provided with a mechanism for irradiating the image exposure light from the exposing means and a transfer means for transferring the toner image onto the transfer material is arranged on both sides of the transfer material. To do.

(A) A polysilane compound containing a photoconductive layer formed by laminating a photocarrier excitation layer and a carrier transport layer containing a polysilane compound (C) below on a conductive substrate having a light-transmitting property. Photoconductor.

(B) A photoconductor containing a polysilane compound, in which a photosensitive layer formed by containing a photocarrier excitation material in a carrier transport material made of the polysilane compound (C) below is formed on a conductive substrate having a light-transmitting property.

(C) Weight average molecular weight: 50,000 to 2,500,000 Weight average molecular weight / number average molecular weight ≦ 10 Hole mobility: 10 ⁻⁵ cm ² / V · second or more The polysilane compound represented by Chemical formula 1 having each characteristic.

[0020]

[Chemical 1]

According to another aspect of the image forming apparatus of the present invention, in the image forming apparatus having the above-mentioned structure, the developer included in the developing means is composed of an insulating toner and a conductive carrier.

[0022]

According to the image forming apparatus of claim 1, in the polysilane compound used for the photosensitive member, the number of compounds having a high degree of polymerization is reduced by decreasing the amount of the compound having a low degree of polymerization as described above. It is specified by the weight average molecular weight Mw, and the spread of the molecular weight distribution to this is specified by the ratio Mw / Mn, which is the ratio with the number average molecular weight Mn. An excellent polysilane compound for a photoreceptor can be obtained.

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

The present inventor has also found that the strength of this polysilane compound can be remarkably enhanced by increasing the weight average molecular weight Mw so that the molecular weight distribution is narrow.
Based on this finding, the present invention provides a polysilane compound-containing photoconductor having excellent hole mobility and film strength stably by forming a carrier-transporting layer composed of the polysilane compound for photoconductor as a surface layer of the photoconductor. Can be provided.

According to the experiments repeated by the present inventor,
Weight average molecular weight Mw is 50,000 to 2,500,000
0, preferably in the range of 200,000 to 2,000,000, and when the weight average molecular weight Mw is less than 50,000, hole mobility is lowered, and further, excellent durability and high strength are obtained. It turned out that I could not get it. On the other hand, this M
When w 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 broadening of the molecular weight distribution
The value of n is preferably 10 or less, preferably 5 or less. Within this range, the object of the present invention can be achieved predominantly.

Thus, according to the image forming apparatus of the first aspect, since the photoconductor containing the polysilane compound having high carrier mobility is mounted, high-speed image formation can be performed and the apparatus itself becomes small.

That is, since the carriers generated inside the photosensitive layer by the light irradiation of the exposing means move at a high speed inside the photosensitive layer, the time for forming an electrostatic latent image is shortened, whereby the drum-shaped image is formed. With the photoconductor, the rotation speed of the drum can be increased, and the image formation can be performed at high speed.
Moreover, even in the charge removal due to the exposure after the transfer, the carriers generated inside the photosensitive layer immediately contribute to the charge removal, so that the area of the photosensitive layer required for the charge removal is narrowed, and the drum-like shape is combined with the speedup of the photosensitive drum. The diameter of the photosensitive member can be reduced, and the image forming apparatus can be downsized.

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, in the invention of claim 2, the developer is constituted by a combination of an insulating toner and a conductive carrier,
Since it is not necessary to indirectly transfer the toner image through the toner image transporting means, the toner image transporting means becomes unnecessary, and as a result, the image forming apparatus can be further downsized.

[0030]

EXAMPLES The present invention will be described below with reference to examples. (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 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
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.

[0033]

[Chemical 3]

The polysilane compound of the present invention has various monomers as described above, but in particular, when the inventors made an intensive study 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 an effect 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 representing the depth of the trap of Poole-Frenkel type hopping conduction, but according to the experiments conducted by the present inventors repeatedly, the increase of E ₀ due to the presence of the aryl group is It was found that this is due to the formation of dimer sites by.

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 a 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 the photosensitive layer 2. The photosensitive layer 2 is composed of a photocarrier excitation layer 3 and a carrier transport layer 4 made of polysilane. May be. Further, FIG. 2 shows a single photosensitive layer 7 in which a carrier transporter 5 made of polysilane and granular photocarrier exciters 6 are contained.

The conductive substrate 1 has a structure in which a transparent conductive layer is formed on a transparent insulating substrate, and there is, for example, one in which the surface of an insulating material such as transparent glass or ceramic is coated with a conductive thin film. 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 a high carrier generation efficiency using, for example, titanyl phthalocyanine, metal phthalocyanine pigment, metal-free phthalocyanine, perylene pigment, polycyclic quinone pigment, squarylium dye, azurenium dye, thiapyrylium dye, trisazo pigment as an organic photoconductive material. 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 prepared 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 based on the above-mentioned basic structure according to required electrophotographic characteristics. 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.

(Formation Method of Polysilane Layer) The carrier transport layer 4 and the photosensitive layer 7 which are polysilane layers can be formed by various known methods.
It is formed by forming a solution of polysilane in an organic solvent and applying and drying the solution by a coating method such as a bar coating method, a dipping method, a melt extrusion method or a spray method. The organic solvent includes 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 one kind or a mixture of two or more kinds thereof is used.

Alternatively, a solution may be prepared in which a low molecular carrier transport agent is added to polysilane together with the above organic solvent, and the solution may be dipped 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, thiazole compounds. ,
There are nitrogen-containing cyclic compounds and condensed polycyclic compounds such as thiadiazole compounds, imidazole compounds, pyrazole compounds and triazole compounds.

These low-molecular-weight carrier transport agents may be contained in the polysilane layer in an amount of 1 to 60% by weight, preferably 5 to 50% by weight. Within this range, the carrier transporting function is enhanced. , The photosensitivity and the residual potential are predominantly exerted, the charging ability is relatively increased, and the sensitivity characteristics are improved.

Furthermore, the polysilane compound according to the present invention can obtain high carrier mobility and film strength. However, in order to further increase strength and hardness, or light fatigue (carrier mobility and film strength) due to long-term exposure to light. A binder resin may be added in order to prevent the decrease). As such a binder resin, one known per se, for example, polystyrene, polyvinyl chloride, polypropylene, polyamide,
Examples include polyimide, polyester, polyether, polyurethane, epoxy resin, polycarbonate, polyacrylate, polyarylate, silicone resin, and polyvinyl butyral. These resins can be 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 them absorb ultraviolet rays by themselves, so that deterioration of polysilane due to ultraviolet rays can be prevented.

(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 optical backside exposure system, which is an electrophotographic image forming apparatus combined so that exposure and development can be performed almost at the same time without corona charging. Is a transparent conductive layer 11 and photocarrier excitation layers 12 and 10 ⁻⁵ c on the transparent support 10.
Carrier transport layer 13 having a mobility of m ² / V · sec or more
A drum-shaped photosensitive member in which and are laminated, 14 is an LED head as an exposing unit, 15 is a developing machine as a developing unit, 1
Reference numeral 6 is a transfer roller as a transfer means. The LED head 14 and the developing machine 15 are arranged substantially symmetrically with a part of the photoconductor 9 interposed therebetween. As such an LED head 14, a small size 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. Further, 17 is not always necessary. The developing machine 15 includes, for example, a cylindrical magnetic pole roller 18 having eight poles and a cylindrical conductive sleeve 19 arranged around the outer circumference thereof, and further serves as a developer stored in the toner receiver 20. A one-component magnetic conductive toner or a two-component developer composed of a conductive magnetic carrier and an insulating toner is delivered to the outer circumference of the sleeve 19 to form a 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. Two
Reference numeral 3 is a toner image formed on the surface of the photoconductor 9, 24 is a recording paper as a transfer material, and 25 is a residual toner after transfer.
In addition to this, the rotation driving means of the developing machine and the rotation means of the photoconductor 9 are provided. Although the LED head is used as the exposure unit 14 here, a laser, a liquid crystal shutter, an EL head, or the like may be used. In addition to the LED array, the erase light source 17
A light source such as a halogen lamp, a fluorescent lamp, or an EL array can be used.

Thus, according to the image forming section 8 having the above-described structure, the LED is arranged from the side of the light-transmissive support 10 of the rotating photoconductor 9.
When light for image exposure is irradiated from the head 14 to generate holes and electrons inside the photocarrier excitation layer 12, if a positive bias voltage is applied to the developing device side, the electrons are driven 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 out, and 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 are combined, and the mobility of the carrier transport layer 13 is set to 1
The carrier generation property is set to 0 ⁻⁵ cm ² / V · sec or more so that carriers generated in the photocarrier excitation layer 12 are efficiently transferred to the surface of the carrier transport layer 13. A high image forming speed can be obtained.

Next, the specific contents of the image forming section 8 having the above-mentioned structure 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 pool 26 formed by the developing machine 15. The developing device 15 for holding the developer includes a conductive sleeve 19 and a magnetic pole roller 1 disposed inside the sleeve.
8, the developer may be conveyed by fixing the magnetic pole roller 18 and rotating the sleeve 19, or the sleeve 1
9 may be fixed and 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 machine 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 the position closest to the photosensitive member 9, and is insulated from the sleeve 19 by the insulator 28. The control electrode 27 is
The sleeve 19 is formed in a strip 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 may be a one-component developer as long as it forms the magnetic brush 21 and the developer pool 26 and has necessary conductivity. It is also possible to use a two-component developer in which a carrier and an insulating toner are mixed at a predetermined mixing ratio 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 exposing at the position of the developer pool 26, the photoconductor 9 is sufficiently charged until the exposure, and the influence of the history of the potential of the photoconductor 9 before charging is suppressed, and the photoconductor 9 is exposed. The residual toner on the surface and the toner on the image background portion are sufficiently collected. Furthermore, since the photosensitive member 9 is sufficiently charged and then exposed to lose the electric charge, the electric attraction between the developer and the photosensitive member 9 is strong, and a good toner image 23 is formed. After the toner image 23 is formed, the photoconductor 9 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 having a good resolution can be obtained.

At the position of the developer pool 26, rather than at 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 to the magnetic pole roller 18 side is weak, and a part of the toner image 23 formed on the surface of the photoconductor 9 is collected by the magnetic force on the developing means side to lower the image density. Therefore, it is possible to prevent the resolution from being deteriorated 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 through 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. If the electric potential of the control electrode 27 is adjusted here, it is possible to obtain the optimum image forming conditions by adjusting the image density, 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 machine 15 in the next image forming process. .

Furthermore, by erasing the charge-removing light from the erase light source 17 to the photoconductor 9 after transfer, the influence of the history of the photoconductor 9 due to the presence or absence of charging or exposure in the previous process can be more effectively canceled. Therefore, it is possible to suppress image problems such as an afterimage phenomenon during repeated use. Further, the 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 machine 15. can do.

Further, the carrier transport layer 13 is made up of the photoconductor 9
Good surface characteristics can be provided even if it doubles as the surface layer. That is, the polysilane compound of the present invention has the features that the surface is hard and has an appropriate slidability, it is excellent in abrasion resistance and printing durability, and the charging property is also good. It is advantageous as a surface layer for use. 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. Moreover, there is an advantage that deterioration of the carrier transfer agent due to invasion from the surface due to a chemical action can be made difficult to occur and the degree of the deterioration can be reduced, which results in a better surface. The 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 arrow direction and rotates in both image forming units 8. The LED head 14 irradiates the photoconductor 9 with light for image exposure, 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 and then fixed.

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.

Examples of the present invention will be described below. (Example 1) In this example, toluene which is a solvent was added to various dichlorosilane which was a starting material, and the temperature was 110 ° C.
Thus, a dechlorination condensation reaction with sodium was carried out, whereby various polysilanes shown in Chemical formulas 4 to 6 were synthesized. And the weight average molecular weight Mw of these polysilanes
The number average molecular weight Mn was measured and Mw / Mn was also determined. The results shown in Table 1 were obtained.

The respective average molecular weights Mw and Mn are measured by using gel permeation chromatography, and columns for that are Asahipak GS-310, GS-510 and G.
Three SM-700 and tetrahydrofuran (THF) were used as the mobile phase, and the resulting effluent was UV254.
It was measured with a detector of nm absorption. In addition, this chromatographic waveform processing was performed using a 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 having different polymerization degrees n are used. -2,
a-3 was synthesized.

In Chemical formula 5, x = y = 1 and z = 0, R ₁ , R ₂ and R ₃ are methyl groups and R ₄ is a phenyl group, and two types of polysilanes having different polymerization degrees n are used. Compound b-
1, b-2 were synthesized.

In the chemical formula 6, x = y = z = 1, and
A polysilane compound c in which R ₁ , R ₂ , R ₅ , and R ₆ are methyl groups and R ₃ and R ₄ are phenyl groups was synthesized.

[0070]

[Chemical 4]

[0071]

[Chemical 5]

[0072]

[Chemical 6]

[0073]

[Table 1]

The carrier mobilities (25 ° C.) of the 6 kinds of polysilane compounds thus obtained were measured.
As shown in.

This carrier mobility is measured by time-of-flight (TOF). According to this TOF,
A parylene blocking electrode is provided on an Al substrate, an a-Se layer that is a carrier excitation layer is further formed, and a layer of each polysilane compound (having a thickness of 10 μm) is formed on the film formation substrate.
m) is applied and formed, and a DC pulse voltage with a pulse width of 10 m.sec is applied to the sample having such a configuration, a uniform electric field is applied to the sample, and after the electric field is applied, N ₂ laser excitation is performed for 4 m.sec. The dye (coumarin 481nm) laser pulse light is irradiated onto the electrode side of the sample with an optical fiber, and the state in which the sheet-like carriers generated in the polysilane layer by the light pulse irradiated onto this electrode side drift due to the applied electric field It is a method of observing as a transient change of.

Each polysilane compound a-1 according to the present invention,
It can be seen that a high hole mobility is obtained for b-1, b-2 and c. Therefore, Mw / Mn is out of the range of the present invention, and the polysilane compound a-2, 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 could not be obtained.

(Example 2) Next, as a transparent conductive layer 11, I was formed on the peripheral surface of a transparent cylindrical glass substrate or plastic.
The TO layer is formed with a thickness of 1000 A by the active reaction vapor deposition method,
Then, a titanyl phthalocyanine and a polyester resin were dipped in a liquid obtained by dispersing and mixing the same in methylene chloride and then dried at 55 ° C. under reduced pressure to form a photocarrier excitation layer 12 made of titanyl phthalocyanine and having a thickness of 15 μm. Next, on the film-formed cylindrical glass substrate, six kinds of polysilane-based carrier transport layers 13 having a thickness of 5 μm corresponding to the six kinds of polysilane compounds of (Example 1) were formed, and the photoreceptor A-1, A-2, A-3, B-1, B-2, and C were produced.

For example, for the photoconductors 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 of poly (trimethylphenyldisilane) obtained by dechlorinating 1,2-dichlorotrimethylphenyldisilane in toluene, Then 1
It was dried with hot air at 00 ° C. As a result, a 5 μm thick polysilane carrier transport layer 13 composed of the polysilane compound b-1 or b-2 is formed, and the photoconductor B-
1 and B-2 were obtained.

Therefore, the photosensitive members A-1 and B of the present invention are used.
-1, B-2, and C are attached to the image forming unit 8 as shown in FIG. 3, a two-component developer including a conductive magnetic carrier and an insulating toner is used as a developer, and a dynamic drive is used. System, an LED head having a resolution of 300 DPI (dots / inch) is arranged, a voltage of Vs = -70 V is applied between the sleeve 19 and the transparent conductive layer 11, and image exposure is performed at a wavelength of 740 nm. A toner image was formed on the photoconductor, and the toner image was transferred to a commercially available plain paper by a transfer roller to which a transfer bias voltage of +200 V was applied, and heat-fixed to obtain an image. In addition, the developer is used as the photoconductor 9
By rotating in the opposite direction to form a developer pool 26, the area 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 background fog, and had a good resolution of 300 DPI.

Therefore, the photoconductors of the comparative examples A-2 and A were used.
-3 was image-evaluated in the same manner as described above. As a result, since the carrier mobility in the carrier-transporting layer was low, the photoresponsiveness was poor, and a sufficient potential contrast was not formed, so that a toner image having a sufficient density was not formed, O. D. Was 0.6 and the image was inadequate.

(Example 3) In this example, the durability of the six types of photoreceptors of (Example 2) was evaluated using the image forming section 8 as shown in FIG.

In the image forming section 8 equipped with each photoconductor, 10,000 sheets were printed, and then the occurrence of scratches on the surface of the photosensitive layer was visually confirmed, and the results shown in Table 2 were obtained. In the table, ○○ marks indicate that no scratches were found, ○ marks appear to cause slight scratches, but there is no problem in practical use, and △ marks indicate scratches. However, it is a case where there is a slight problem in practical use, and a mark “X” is a case in which scratches are significantly generated and a problem occurs in practical use.

[0084]

[Table 2]

As is clear from the results shown in Table 2, it is understood that all the photoreceptors according to the present invention have excellent film strength and good durability.

Example 4 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 is formed to a thickness of 1000 A by the active reaction vapor deposition method, and then it is mounted in a glow discharge decomposition apparatus, and the inside of the reaction vessel is completely evacuated, then SiH ₄ gas and B are added.
_A discharge voltage was applied while flowing a ₂ H ₆ gas at a constant ratio to form an a-Si · B · H carrier injection blocking layer having a thickness of 0.5 μm. After that, the injection of B ₂ H ₆ gas was stopped and the SiH
_{The 4} gas was controlled to a constant flow rate to form the photocarrier excitation layer 12 having a thickness of 2 μm. Next, this film-forming cylindrical glass substrate
Similar to the six types of photoconductors of (Example 2), six types of 5 μm thick polysilane carrier transport layers 13 corresponding to the six types of polysilane compounds of (Example 1) were formed, and the photoconductor A =
1, A = 2, A = 3, B = 1, B = 2, and C = 1 were produced.

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

When this image was evaluated, it was found that no matter what kind of photoreceptor was used, the result 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.

Therefore, the photosensitive member of the comparative example is A = 2, A
= 3 was image-evaluated in the same manner as described above. As a result, since the carrier mobility in the carrier-transporting layer was low, the photoresponsiveness was poor, and a sufficient potential contrast was not formed, so that a toner image having a sufficient density was not formed. O. D. Was 0.7 and the image was insufficient.

(Example 5) In this example, the durability of the six types of photoreceptors of (Example 4) was evaluated in the same manner as in (Example 3). The same results were obtained, and the photoreceptor of the present invention was obtained. Then, it was found that all of them had excellent film strength and good durability.

Example 6 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 is formed to a thickness of 1000 A by the active reaction vapor deposition method, and then 2 μm of a-Se is formed by the vacuum vapor deposition method.
An m-thick photocarrier excitation layer 12 was formed. Next, the film-formed cylindrical glass substrate was provided with 6 kinds of 5 μm-thick polysilane-based carrier transport layers 13 corresponding to the 6 kinds of polysilane compounds of (Example 1) as in the case of 6 kinds of photoreceptors of (Example 2). After being formed, six types of photoconductors were sequentially manufactured.

Therefore, the four types of photoconductors of the present invention are respectively mounted on the image forming section 8, and a toner image is similarly formed on the photoconductor under the conditions described in (Example 2), and the toner images are formed. An image was obtained by transferring the image onto a commercially available plain paper by a transfer roller and thermally fixing it. D.
Had an image density of 1.4 or more, there was no background fogging, and the resolution was a good image of 300 DPI.

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

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

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) by the active reaction vapor deposition method to a thickness of 1000 A, and then 1 Poly (trimethylphenyldisilane) obtained by dechlorinating 2,2-dichlorotrimethylphenyldisilane is dissolved in toluene, and a-Si
After mixing with the solution containing the powder of the system, the above-mentioned film-forming cylindrical glass substrate was immersed, 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
Mn and Hall mobility were measured.
It was 2,000,000, 3,6 × 10 ⁻⁴ cm ² / V · sec.

Therefore, this photosensitive member is mounted on the image forming section 8, a toner image is formed on the photosensitive member under the conditions described in (Example 2), 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. Further, when the durability of this photoconductor was evaluated in the same manner as in (Example 3), 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) by the active reaction vapor deposition method to a thickness of 1000 A, and then 1 Poly (trimethylphenyldisilane) obtained by dechlorinating and polymerizing 2,2-dichlorotrimethylphenyldisilane is dissolved in toluene, and TiOP
c powder is dispersed by an ultrasonic dispersion method and mixed with the contained solution, and then the above film-forming cylindrical glass substrate is immersed,
Then, it dried with 100 degreeC hot air. 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
Mn and Hall mobility were measured.
It was 1,700,000, 3,6 × 10 ⁻⁴ cm ² / V · sec.

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 2) 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. Further, when the durability of this photoconductor was evaluated in the same manner as in (Example 3), 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, B-1, B-2, C of (Example 2) which is a photoreceptor of the present invention, A = 1 of (Example 3), When B = 1, B = 2, C = 1, and the (Example 7) and (Example 8) photoconductors according to the present invention are mounted on the image forming apparatus 30 of FIG. By feeding the paper 24 once, it is possible to print on both sides at the same time, the rotational speed of the drum-shaped photoconductor can be further increased, and the image formation can be performed at high speed. 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.

[0103]

As described above, the polysilane compound for a photoreceptor used in the photoreceptor according to the present invention has a weight average molecular weight Mw of the polysilane compound of 50,000 to 2,500,000.
And a hole mobility of 10 ⁻⁵ cm ² / V · sec or more can be obtained by forming the polysilane compound to form a carrier transport layer. By doing so, a polysilane compound-containing photoreceptor having high hole mobility can be stably provided. Moreover, the strength of the photosensitive layer can be remarkably increased by increasing the Mw and narrowing the molecular weight distribution, so that a highly reliable photoreceptor having excellent durability can be provided.

Further, in the present invention, the required polysilane compound can be easily produced by setting Mw and Mn, and thereby a high-quality photoconductor can be stably produced. There is an advantage that the 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 electrostatic latent image is formed. Therefore, the rotation speed of the drum-shaped photoconductor can be increased, and the image formation can be performed at high speed. Moreover, even in the charge removal due to the exposure after the transfer, the carriers generated inside the photosensitive layer immediately contribute to the charge removal, so that the area of the photosensitive layer required for the charge removal is narrowed, and the drum-like shape is combined with the speedup of the photosensitive drum. The diameter of the photosensitive member can be reduced, and the image forming apparatus can be downsized.

Further, according to the image forming apparatus proposed by 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 Material 7 Single Photosensitive Layer 8 Image Forming Section

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Ryuichi Maekawa 22 Kyocera Corporation, 5-5 Higashinokitainouemachi, Yamashina-ku, Kyoto-shi, Kyoto Prefecture

Claims (2)

[Claims] 1. An exposing means for irradiating an image exposing light on the conductive substrate side of the polysilane compound-containing photoreceptor of the following (A) or (B), and a developing means on the photosensitive layer side. A mechanism for providing a voltage applying means for applying a voltage between the conductive substrate and a mechanism for irradiating image exposing 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. An image forming unit including a transfer unit that transfers the toner image onto a transfer target material;
An image forming apparatus that is arranged on both sides of a transfer material. (A) A polysilane compound-containing photoreceptor having a photosensitive layer formed by laminating a photocarrier excitation layer and a carrier transport layer containing a polysilane compound (C) below on a conductive substrate having a light-transmitting property. (B) A polysilane compound-containing photoreceptor in which a photosensitive layer is formed on a light-transmissive conductive substrate by forming a photocarrier excitation material in a carrier transport material (C) shown below. (C) Weight average molecular weight: 50,000 to 2,500,000 Weight average molecular weight / number average molecular weight ≦ 10 Hole mobility: 10 ⁻⁵ cm ² / V · second or more The polysilane compound represented by Chemical formula 1 having each characteristic. [Chemical 1] 2. The image forming apparatus according to claim 1, wherein the developer included in the developing unit includes an insulating toner and a conductive carrier.