JPH10133404A - Photoconductor and image forming apparatus - Google Patents

Abstract

(57) [Problem] To provide a high-performance and low-cost photoreceptor having high hole mobility. A photosensitive layer (2) is formed by laminating a photocarrier excitation layer (3) and a polysilane-based carrier transport layer (4) having a magnetic field orientation.
Formed on a conductive substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoreceptor having a polysilane-based carrier transport layer provided with a magnetic field orientation and an image forming apparatus equipped with the photoreceptor.

[0002]

2. Description of the Related Art A polymer material such as poly-N-vinylcarbazole (PVK) has been used as a material for a carrier transport layer of an electrophotographic photoreceptor. To meet this requirement, a low-molecular-weight resin-dispersed composite material has been proposed in which a low-molecular-weight compound such as an annealed amine derivative or a hydrazone derivative is dispersed in an inert polymer binder such as a polycarbonate resin.

[0003] However, the recent demand for high carrier mobility in carrier transport materials is not yet a satisfactory situation, and higher carrier mobility, particularly higher hole mobility, is required. For example, for an image forming apparatus requiring high carrier mobility, it has been proposed to employ a polysilane compound as a material for a carrier transport layer of a photoreceptor. However, when polysilane is used alone, the weight average of the polysilane compound is Molecular weight 50,000-2,50
A polysilane compound having a molecular weight of 10,000 and a ratio of not more than 10 compared to the number average molecular weight and having a hole mobility of not less than 10 −5 cm 2 / V · sec has also been proposed.

[0004]

However, in order to cope with a higher-speed image forming apparatus, even though higher hole movement is required, a molecular design relating to the synthesis of high-mobility polysilane has been established. Not.

[0005] However, it is generally said that polysilane compounds exhibit higher hole mobility if the molecules can be oriented in a certain direction. I have.

(1) Rubbing (Reference: Macromolecul)
es, 26, 2520 (1993)).

(2) Stretch orientation (Reference: 74th Electrographic Society of Japan, B19, p191 (1995)). This is a technique in which a plasticizer is added to polysilane, a film is formed on a substrate from a toluene solution by a bar coating method, and then the film is peeled off and stretched uniaxially for orientation.

(3) Langmuir Blodget (References: Macromolecules, 24, 5068 (1991), Macromolecules, 2)
5,3825 (1992), Macromolecules, 28,1773 (1995)).

(4) Electric field application (Reference: Jpn.Appl.Phy
s., 34, L57 (1995)). This is because a toluene solution in which polysilane is dissolved is placed on an aluminum comb electrode to which a DC voltage is applied.
This is a technique in which 0 μl is dropped, a toluene solution is evaporated to form a film, and an electric field is applied thereto to orient the film.

However, rubbing of (1) and (3)
The electrical properties of the Langmuir Blodget have not yet been determined by measurement.

In addition, the stretching orientation in (2) and the application of an electric field in (4) are not practical because it is difficult to orient the molecules on the drum-shaped photosensitive member due to the shape. There is.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a high-performance and low-cost photoreceptor having high hole mobility by solving all of the above problems. Another object of the present invention is to provide an image forming apparatus equipped with the photoconductor of the present invention.

[0013]

The photoreceptor of the present invention has a photosensitive layer formed by laminating a photocarrier excitation layer and a polysilane-based carrier transport layer of the following chemical formula, which is oriented in a magnetic field, and is formed on a conductive substrate. It is characterized by the following.

[0014]

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[0015] The image forming apparatus of the present invention, the photoreceptor of the present invention, developing means disposed on the photosensitive layer side of the photoreceptor, and exposing means for irradiating image exposure light from the conductive substrate having translucency. And a device for irradiating image exposure light from the exposure unit while applying a voltage between the developing unit and the conductive substrate to form a toner image on the surface of the photoreceptor. .

Another image forming apparatus of the present invention comprises the photoreceptor of the present invention, a charging unit for applying a charge to the surface of the photoreceptor, and an exposing unit for irradiating the charged area of the photoreceptor with light. Developing means for forming an electrostatic latent image on the surface of the photoreceptor by means of the charging means and exposure means, forming a toner image corresponding to the electrostatic latent image on the photoreceptor, and transferring the toner image to a material to be transferred Means, cleaning means for removing residual toner on the photoreceptor surface after transfer, and charge removing means for removing residual electrostatic latent images after transfer.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the polysilane compound shown in Structure 1 of the polysilane compound, R1 to R6 are, in addition to hydrogen,
There are an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxy group, and a substituted alkoxy group. Examples of the alkyl, aryl, and alkoxy groups include methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, nonyl, decyl, pentadecyl, stearyl, cyclohexyl, phenyl, tolyl, xylyl,
Naphthyl, methoxy, ethoxy and the like can be mentioned. Also,
These substituents include alkyl, aryl, halogen,
Examples include nitro, amino, alkoxy, cyano and the like.

The polysilane compound is represented by 0 or 1, since x, y, and z represent the presence or absence of each unit as shown in Chemical formula 1. For example, if x = y = 1 and z = 0, the composition is such that two types of units are alternately and continuously arranged. Further, as shown in Chemical formula 2, a copolymer (copolymer) of the polysilane compound of Chemical formula 1 may be used.

[0019]

Embedded image

That is, x, y, z, x ', y', z '
Is selectively set to 0 or 1, and various combinations can be made depending on the presence or absence of each unit. For example,
Compound of a polymer composed of three types of monomers and a polymer composed of three types of monomers, 3
A compound of a polymer composed of two types of monomers and a polymer composed of two types of monomers, a compound composed of a polymer composed of three types of monomers and a polymer composed of one type of monomer, and two types of units Compound of polymer consisting of monomers and polymer consisting of two kinds of monomers, compound consisting of polymer consisting of two kinds of monomers and polymer consisting of one kind of monomer, polymer consisting of one kind of monomer And a polymer consisting of one type of monomer. Further, compounds obtained by combining these compounds may be used.

[0021] Configuration FIG. 1 and FIG. 2 of the photosensitive member of the magnetic field orientation polysilane compound is a basic layer structure of the present invention photoreceptor 1 to form a laminate type photosensitive layer 2 on the conductive substrate 1 The photosensitive layer 2 is composed of a photocarrier excitation layer 3 and a carrier transport layer 4 made of a polysilane compound, and the order of the layers 3 and 4 may be changed. FIG. 2 shows a carrier transporter 5 made of a polysilane compound.
Is a single photosensitive layer 7 containing a granular photocarrier exciter 6.

Each of these photoreceptors is subjected to molecular orientation with respect to the polysilane compound of the carrier transport layer (carrier transporter) by using a magnetic field orientation device described later.

Copper, brass, SUS, A
There is a metal conductor such as l, Ni or the like, or an insulator such as glass or ceramic coated with a conductive thin film, or a structure in which a transparent conductive layer is formed on a transparent insulating substrate.

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

As a constituent material of the photocarrier excitation layer 3 and the photocarrier excitation body 6, an organic or inorganic photoconductive material known per se can be used. Organic having high carrier generation efficiency using, for example, titanyl phthalocyanine, metal phthalocyanine pigment, metal-free phthalocyanine, perylene pigment, polycyclic quinoline pigment, squarylium dye, azulenium dye, thiapyrylium dye, trisazo pigment, etc. as an organic photoconductive material An optical semiconductor is chosen. As an inorganic photoconductive material, for example, amorphous Se, SeAs, SeTe or Si (a-Se, a-SeAs, a-SeTe, a-Se
Si), CdS, ZnO and the like. If the photocarrier excitation layer 3 is to be formed, a vacuum deposition method, an active reactive deposition method, an ion plating method, an RF sputtering method,
Sputtering method, RF magnetron sputtering method, DC
Magnetron sputtering, thermal CVD, plasma CV
Use the D method.

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

When an a-Si type powder is used as the particulate photocarrier exciter 6 of the photosensitive layer 7, this powder is
It can be formed in the same manner as the Si-based photocarrier excitation layer 2, and has a granular shape, a columnar shape, and a flake shape. The diameter may be 0.15-5 μm, preferably 0.1-3 μm, and the powder may be contained in the layer at 1-80% by weight, preferably 5-60% by weight. In this case, the particles are dispersed by a stirring method, an ultrasonic dispersion method, or the like.

In addition, titanyl phthalocyanine (TiOPc
) May be dispersed in polysilane to form the photosensitive layer 7, which can have high sensitivity particularly to image exposure on the long wavelength side. This TIOPc is subjected to purification treatment such as sublimation purification, acid or alkali refining of the raw material, and kneaded with milling aids and solvents using various dispersers, or formed into fine particles by vapor deposition. The particles are adjusted to particles and dispersed in polysilane using various solvents. The content of TiOPc is
It may be contained in an amount of 1 to 80% by weight, preferably 10 to 60% by weight in the layer. When the content is less than 1% by weight, the amount of generated carriers is reduced. When the content exceeds 80% by weight, a uniform and high-strength film cannot be produced.

The photoreceptor of the present invention may be further improved or changed in accordance with the required electrophotographic characteristics based on the above basic constitution. For example, by providing an intermediate layer between the substrate 1 and the photosensitive layers 2 and 7 thereon, the chargeability can be increased and the residual potential can be reduced. Alternatively, a surface layer may be provided on these photosensitive layers 2 and 7 to enhance the chargeability and the durability thereof.

Method for Forming Polysilane Layer The carrier transporting layer 4 and the photosensitive layer 7, which are polysilane layers, can be formed by various known methods. For example, polysilane is dissolved in an organic solvent to form a solution.
It is formed by applying and drying a coating method such as a bar code method, a dipping method, a melt extrusion method, and a spray method. Examples of the organic solvent include aromatic hydrocarbons such as benzene and toluene, alcohols such as methyl alcohol, ethyl alcohol and IPA, ethers such as tetrahydrofuran and dimethyl ether, ketones such as acetone and methyl ethyl ketone, esters and halogens. , Halogenated hydrocarbons and the like are used, and one kind or a mixture of two or more kinds is used.

The carrier transport layer may be composed of only a polysilane compound, but may be mixed with an organic low molecular carrier transport material or a polymer resin.

Examples of the organic low molecular weight carrier transporting substance include phenylenediamine compounds, oxadiazole compounds, styryl compounds, hydrazone compounds, hydrazoline compounds, triphenylamine compounds, indole compounds, oxazole compounds, Isoxazole compounds, thiazole compounds, thiazol compounds, imidazole compounds, pyrazole compounds,
There are nitrogen-containing cyclic compounds such as triazole compounds and condensed polycyclic compounds. The content of the organic low molecular carrier transporting material may be in the range of 0.1 to 100% based on the content of the polysilane.

As the polymer resin, for example, polycarbonate, polystyrene, PMMA, binder resin, polystyrene, polyvinyl chloride, polyvinyl acetate, polypropylene, polybutadiene, polyamide, polyimide, polyester, polyether, polyurethane, epoxy resin, polycarbonate, poly Examples include acrylate, silicone resin, phenol resin, and polyvinyl butyral. The content of the polymer resin may be in the range of 50 to 150% based on the sum of the contents of the polysilane and the low-molecular carrier transporting material. When the content ratio is less than 50%, a high-strength film cannot be obtained, and when it exceeds 150%, the transporting ability of the carrier decreases.

Structure of Magnetic Field Orienting Apparatus Each photoreceptor has a magnetic field orienting apparatus 41 shown in FIGS. 6 and 7 or a magnetic field orienting apparatus 42 shown in FIGS. 8 and 9.
Thus, molecular orientation is performed on the polysilane compound of the carrier transport layer (carrier transporter).

The former magnetic field orientation device 41 is shown in FIG.
Is a schematic cross-sectional view, and FIG. 7 is a schematic top view. 43, 4
Reference numeral 4 denotes a housing made of a semi-cylindrical magnet containing liquid nitrogen 45. The housing 43 has an N pole, and the housing 44 has an S pole. A magnetic field is generated between the housings 43 and 44, and the photoconductor 46 is disposed in the magnetic field.

FIG. 8 is a schematic sectional view of the latter magnetic field aligner 42, and FIG. 9 is a schematic top view thereof.
Reference numeral 47 denotes a housing made of a cylindrical S-pole magnet containing liquid nitrogen 45, and reference numeral 48 denotes a small cylinder made of a cylindrical N-pole magnet containing liquid nitrogen 45.
A magnetic field is generated between 7 and the cylindrical body 48, and the photoconductor 46 is arranged in the magnetic field.

By using the magnetic field alignment devices 41 and 42, the polysilane compound of the carrier transport layer (carrier transporter) is molecularly oriented, whereby the polysilane compound is uniformly oriented in the film thickness direction. Also achieve high hole mobility.

Then, these magnetic field alignment devices 41 and 42
Can be integrated into some of the traditional OPC applicators,
Thereby, a low-cost magnetic-field-aligned polysilane-containing photoconductor can be manufactured.

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

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

(Light Back Exposure Method) Next, an image forming apparatus (printer) of the light back exposure method to which the features of the present invention can be most applied will be described in detail.

FIG. 3 is a schematic view showing the image forming apparatus 8 of the above-mentioned light back exposure type, which is an electrophotographic type image forming apparatus in which corona charging is unnecessary and exposure and development can be performed almost simultaneously. In the figure, 9 is a translucent support 1
The light-transmitting conductive layer 11 and the photocarrier excitation layers 12 and 10
A drum-shaped photoconductor on which a carrier transport layer 13 having a mobility of ^-5 cm ² / V · sec or more is laminated, 14 is an LED head as exposure means, 15 is a developing machine as developing means, and 16 is transfer. This is a transfer roller as a means. LED
The head 14 and the developing device 15 are arranged substantially symmetrically via a part of the photoconductor 9. 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 serving as an erase light source serving as a charge removing unit, and may be arranged outside the photoconductor 9. Also, 17 is not always required. The developing device 15 includes, for example, a columnar magnetic pole roller 18 having eight poles, and a cylindrical conductive sleeve 19 disposed around the outer circumference thereof. The one-component magnetic conductive toner or the two-component developer including the conductive magnetic carrier and the insulating toner is delivered to the outer periphery of the sleeve 19 to form the magnetic brush 21. A bias power supply 2 is provided between the sleeve 19 and the light-transmitting conductive layer 11.
A positive or negative voltage (300 V or less) is applied between the two 11 and 22 depending on the potential characteristics of the photoconductor 9. 23 is a toner image formed on the surface of the photoconductor 9;
Numeral 24 denotes recording paper as a material to be transferred, and 25 denotes residual toner after transfer. In addition, the rotation driving means of the developing machine and the photoconductor 9
And rotation means. Although an LED head is used here as the exposure means 14, a laser, a liquid crystal shutter, an EL
A 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 apparatus 8 having the above-described structure, the LED is disposed on the rotating photosensitive member 9 from the side of the translucent support 10.
When the head 14 irradiates light for image exposure to generate holes and electrons inside the photocarrier excitation layer 12, if a + bias voltage is applied to the developing device side, the electrons are generated by the bias voltage. Move to the surface side of the transport layer 13,
The positive charges at the ends of the magnetic brush 21 cancel each other, and the toner adheres to the surface of the photoconductor 9. Then, the toner is transferred onto the recording paper 24 by the transfer roller 16 and then fixed.

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

Next, the specific contents of the image forming apparatus having the above configuration will be described in more detail with reference to FIG. FIG. 4 is an explanatory view showing a part of the photoconductor 9 and a developer reservoir 26 formed by the developing device 15.

The developing device 15 for holding the developer includes a conductive sleeve 19 and the magnetic pole roller 1 disposed therein.
8, the developer may be transported by rotating the sleeve 19 while fixing the magnetic pole roller 18 or
9, the magnetic pole roller 18 inside may be rotated.

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

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

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

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

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

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

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

Further, the light source 1 for erasing is applied to the photosensitive member 9 after the transfer.
By irradiating static elimination light by 7, the influence of the history of the photoreceptor 9 due to the presence or absence of charging or exposure in the previous process can be more effectively canceled out, and the image on the image such as an afterimage phenomenon during repeated use can be eliminated. Problems can be suppressed. In addition, the charge trapped on the surface of the carrier transport layer 13 of the photoconductor 9 is erased, the electric attraction between the photoconductor 9 and the residual toner on the surface is eliminated, and the residual toner is easily collected by the developing device 15. can do.

Further, this carrier transport layer 13 is
Good surface characteristics can be provided even when the surface layer also serves as the surface layer. That is, the polysilane compound of the present invention has a feature that the surface is hard and has an appropriate slipperiness, and is excellent in abrasion resistance and printing durability, and also has good charging characteristics. It is advantageous as an application surface layer.
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.

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

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

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

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

[0060]

【Example】

(Example 1) In this example, toluene as a solvent was added to various dichlorosilanes as starting materials, and
A dechlorination-condensation reaction with sodium was carried out at a reaction temperature of ° C to synthesize polysilanes represented by Chemical Formulas 3 to 6. Then, the weight average molecular weight Mw and the number average molecular weight Mn of these polysilanes were measured using gel permeation chromatography, and Mw / Mn was also determined. The results shown in Table 1 were obtained.

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

[0062]

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[0063]

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[0064]

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[0065]

Embedded image

In the chemical formula 3, x = 1, y = z = 0, and R1
Is a methyl group, R2 is a phenyl group, and the polymerization degree is changed.
Various kinds of polysilane compounds a-1, a-2 and a-3 were synthesized.
In the chemical formula 4, x = 1, y = z = 0, R1 is a methyl group,
A polysilane compound b in which R2 is a normal propyl group was synthesized. Further, in the chemical formula 5, x = y = 1, z = 0, and
A polysilane compound c in which R1, R2 and R3 are methyl groups and R4 is a phenyl group was synthesized. Further, in the chemical formula 6, x = 1, y =
A polysilane compound d was prepared in which z = 0, x ′ = 1, y ′ = z ′ = 0, R1, R2, and R′1 were methyl groups and R′2 was a phenyl group.

[0067]

[Table 1]

When the carrier mobility of each polysilane compound was measured, the results shown in Table 1 were obtained. This carrier mobility is a time-off flight (TO
F) (25 ° C.). According to the TOF, a parylene blocking electrode is provided on an Al substrate,
Further, an a-Se layer serving as a carrier excitation layer is formed, and a layer (thickness: 10) of each of the above polysilane compounds is formed on the film formation substrate.
μm) is applied to form a sample having such a configuration.
A DC pulse voltage having a pulse width of 10 m.sec is applied, a uniform electric field is applied to the sample, and after applying the electric field, N ₂ is applied at 4 m.sec.
A laser-excited dye (coumarin 481 nm) laser pulse light is irradiated on the electrode side of the sample with an optical fiber, and the sheet-like carrier generated in the polysilane layer by the light pulse irradiated on the electrode side drifts due to an applied electric field. This is a method of observing as a transient change of the external current.

(Example 2) An ITO layer having a thickness of 1000 mm was formed as a transparent conductive layer 11 on the peripheral surface of a transparent cylindrical glass substrate or plastic by an active reaction vapor deposition method, and then titanyl phthalocyanine and a polyester resin were formed thereon. Was immersed in a liquid mixed and dispersed in chloroform, and then dried to form a 3 μm-thick photocarrier excitation layer 12 made of titanyl phthalocyanine.

Next, the polysilane synthesized in (Example 1) was dissolved in chloroform to prepare a polysilane / chloroform solution. The film-formed cylindrical glass substrate prepared above was immersed in this polysilane / chloroform solution, and then dried to form a 20 μm-thick photocarrier transport layer 13 made of polysilane, thereby producing a photoconductor containing a polysilane compound.

(Example 3) The photosensitive member produced in (Example 2) is shown in FIG.
The polysilane compound was oriented in a certain direction by the magnetic field orientation devices 41 and 42 shown in FIGS. When the carrier mobility (25 ° C.) of each photoconductor thus obtained was measured, the results shown in Table 2 were obtained. As is clear from the table, compared to the polysilane photoconductor without magnetic field orientation,
It can be seen that the value is larger by about one digit.

[0072]

[Table 2]

(Example 4) The photoreceptor containing a magnetically oriented polysilane compound prepared in (Example 3) was mounted on an image forming apparatus 8 as shown in FIG. 3, and the developer was composed of a conductive magnetic carrier and an insulating toner. Using a component developer, a dynamic drive type LED head with a resolution of 300 dpi is arranged, a voltage of Vs = 400 V is applied between the sleeve 19 and the transparent conductive layer 11, and image exposure is performed at a wavelength of 660 nm. A toner image was formed on the photoreceptor, and the toner image was transferred to plain paper by a transfer roller to which a transfer bias voltage of -400 V was applied, and heat-fixed to obtain an image. The developer was rotated in the opposite direction to the photoreceptor 9 to form a developing pool 26, and the portion was exposed.

When this image was evaluated, the optical density was 1.
A good image having an image density of 4 or more, no fogging of the back, and a resolution of 300 dpi was obtained. In addition, when this magnetic field oriented photoreceptor was used, a sufficiently good image was obtained not only at a low speed of about 10 sheets / min, but also at a high speed of about 40 to 50 sheets / min.

On the other hand, when a similar experiment was performed using a polysilane-containing photoreceptor without a magnetic field orientation, 10 sheets /
Although a sufficient image can be obtained up to a speed of about one minute, when performed at a speed higher than that, the photo-responsiveness is poor due to low carrier mobility in the carrier transport layer, and a sufficient potential contrast is not formed. A toner having a sufficient density was not formed, resulting in an insufficient image.

(Example 5) Next, in the present invention, an organic photoconductive material made of titanyl phthalocyanine was formed as a photocarrier excitation layer 12 on the peripheral surface of an Al cylinder in the same manner as in (Example 2). Similarly to the two types of photoreceptors of the present invention described in (Example 2), a 20 μm-thick polysilane-based carrier transport layer 13 containing the polysilane compound described in (Example 1) is formed, and the photoreceptor is formed. Created. Further, the polysilane compound was magnetically oriented by the same operation as in (Example 3).

With respect to the photoreceptor thus obtained,
Charged using a corona charger to which a voltage of -6 kV was applied,
When the initial charging potential was determined by measuring the surface potential of the dark area,
It showed a charging potential of 800 V, confirming that it had a high charging ability.

Next, after charging the surface potential to -800V,
Irradiate light with a wavelength of 650nm to raise the surface potential from -500V to -2
The exposure energy (half-exposure amount) required to attenuate the voltage to 50 V was measured, and the half-life was determined by the reciprocal. The half-life was 2.0 (cm2 / μJ), indicating a high light sensitivity.
Further, when the spectral sensitivity characteristics were examined by changing the exposure wavelength, an exposure amount that was twice the half-reduced exposure amount was given over a range of 600 to 800 nm, and the surface potential at that time was determined as a residual potential. Low, showing excellent properties.

Next, these photoreceptors are mounted on a printer (image forming apparatus 30) by the Carlson method having the structure shown in FIG. 5, and a dynamic drive type LED having a wavelength of 650 nm and a resolution of 400 dpi (dot / inch) is used as an exposure means. An image was formed using a head, and the image was evaluated with respect to the image density, resolution, back fog, and afterimage (ghost). As a result, the image density was 1.
The resolution was excellent at 400 dpi, no fogging of the background, no afterimage was observed, and the rotation speed of the drum-shaped photoconductor was increased. In addition, even if image formation was continuously performed on 10,000 sheets, no change in image quality such as a decrease in image density or resolution or an increase in fog of the back was observed, and it was confirmed that the image had excellent durability. .

(Example 6) Each of the photoreceptors of (Example 5) is mounted on a commercially available copying machine according to the Carlson method, and an image is similarly formed using an optical system for irradiating the photoreceptor with light reflected from a document as exposure means. After forming, an image having excellent image quality in all of image density, resolution, back fog, gradation reproducibility, and afterimage was obtained, and the rotation speed of the drum-shaped photosensitive member was increased, and the photosensitive material for a copying machine was obtained. It was confirmed that it had excellent properties as a body.

It should be noted that the present invention is not limited to the above-described embodiment, and any improvements, changes, etc. may be made without departing from the scope of the present invention.

[0082]

As described above, according to the present invention, the polysilane compound for photoreceptor is subjected to magnetic field orientation to obtain a polysilane compound having a hole mobility which is higher by about one digit than conventional ones. By forming a carrier transport layer from this polysilane compound, a polysilane compound-containing photoreceptor having high hole mobility was stably provided.

Further, in the photoreceptor of the present invention, since a magnetic field alignment step can be incorporated between the conventional dipping step and the drying step, a large-scale apparatus for the magnetic field alignment is not required, and the conventional photoreceptor can be used. The polysilane orientation could be achieved with a simple device, thereby providing a high-performance photoreceptor at low cost.

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

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

[Brief description of the drawings]

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

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

FIG. 3 is a schematic view of the image forming apparatus of the present invention.

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

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

FIG. 6 is a schematic sectional view of a magnetic field alignment device.

FIG. 7 is a schematic top view of a magnetic field alignment device.

FIG. 8 is a schematic sectional view of a magnetic field alignment device.

FIG. 9 is a schematic top view of a magnetic field alignment device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive substrate 2 Stacked photosensitive layer 3 Photocarrier excitation layer 4 Carrier transport layer 5 Carrier transporter 6 Photocarrier exciter 7 Single photosensitive layer 41, 42 Magnetic field alignment device

Claims (3)

[Claims] 1. A photoconductor in which a photosensitive layer formed by laminating a photocarrier excitation layer and a polysilane-based carrier transporting layer of the following chemical formula having a magnetic field orientation is formed on a conductive substrate. Embedded image 2. The photoconductor according to claim 1, further comprising: developing means disposed on the photosensitive layer side of the photoconductor; and exposing means for irradiating image exposure light from a conductive substrate having translucency. An image forming apparatus configured to irradiate image exposure light from an exposure unit while applying a voltage between the developing unit and a conductive substrate so as to form a toner image on a surface of the photoconductor. 3. The photoreceptor of claim 1, a charging unit for applying a charge to the surface of the photoreceptor, and an exposure unit for irradiating the charged area of the photoreceptor with light. Forms an electrostatic latent image on the photoreceptor surface,
Developing means for forming a toner image corresponding to the electrostatic latent image on the photoreceptor, transfer means for transferring the toner image to a material to be transferred, cleaning means for removing residual toner on the photoreceptor surface after the transfer, and transfer An image forming apparatus provided with a static eliminator for removing a residual electrostatic latent image later.