JP2000347478A - Contact type electrifying device and image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make applicable sufficient electrification voltage to a body to be electrified because of a high injection speed, to make keepable resisting properties to the fluctuations of the environment in such as humidity and to make reducible the fluctuation of the electrification voltage even in a long term use by providing carbon nanotubes on the surface in contact with the body to be electrified. SOLUTION: An electrifying brush 110 comes into contact with the surface of a photoreceptor 100 being a body to be electrified mainly through the nanotubes 120. An electric charge can be directly injected to an organic photosensitive layer 102 from the carbon nanotubes 120. In comparison with a conventional brush whose electrically conductive fibers 112 consist of fibers obtained by etching or dividing fibers, the area where the charge is exchanged between the organic photosensitive layer 102 and the electrifying brush 110 i.e., the substantial contact area of the layer 102 with the brush 110 is remarkably enlarged. As a result, the injection speed of the charge can be accelerated so that the sufficient electrification voltage can be obtained even in a high-speed image recorder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer,
The present invention relates to a contact type charger for an image recording apparatus such as a facsimile and an image recording apparatus having the contact type charger.

[0002]

2. Description of the Related Art Conventionally, as a charging method for charging the surface of an object to be charged, a corotron and a scorotron for performing corona discharge have been mainly used, but the charging method is being shifted to a roller charging method. The roller charging method is a method in which a charging roller made of a conductive rubber roller is brought into contact with a photoreceptor as a member to be charged, and discharge is caused in a minute gap between the photoreceptor and the charging roller to charge the surface of the photoreceptor. And ozone is significantly reduced as compared with Corotron (reduced to 1/100 to 1/500). Recently, a charge injection method has attracted attention.

The charge injection method is a method in which a charge is directly injected from a contact-type charger to an object to be charged without causing discharge, and the object to be charged is charged. In principle, ozone is not generated. In the charge injection method, the contact resistance between the contact type charger and the photoconductor is low because the contact resistance between the contact type charger and the photoconductor and the capacity of the minute space affect the injection speed when injecting the charge. It is considered better.

For this reason, in the contact-type charger described in Japanese Patent Application Laid-Open No. 6-75459, tetracyanoquinodimethane (T
A charge transfer complex composed of an electron-accepting compound such as CNQ) and an electron-donating compound such as tetrathiafulvalene (TTF) is replaced by a polymer network, and a conductive material made of a polymer material having conductivity provided as a whole. The charging roller is made of rubber.

In Japanese Unexamined Patent Publication No. Hei 7-140729, electric charges are injected into a photosensitive member using a water-absorbing sponge roller. Japanese Patent Application Laid-Open No. Hei 9-101649 discloses FIG.
As shown in FIG. 1, a conductive fiber 111
Metal core 1111 of charging brush 1110 formed by flocking 2
A charging bias is applied from a DC power supply 1103 to the photosensitive layer 1102 on the base 1101 by a charging brush 1110.
In the contact type charger for charging the photoreceptor 1100 formed by the above, the conductive area of the conductive fiber 1112 and the photoreceptor 1100 is increased by changing the conductive fiber 1112 of the charging brush 1110 into an etching fiber or a split fiber. To increase the speed of charge injection.

Here, the etching fiber is a fiber obtained by dissolving a part of the conductive fiber component with a chemical solution and dividing one conductive fiber into a plurality of fibers in the thickness direction. The split fiber is a fiber obtained by splitting one conductive fiber in the thickness direction by utilizing a difference in heat shrinkage of each part at the time of heating. By using the etched fibers or split fibers formed by these processes, the conductive fibers having a small diameter are used, and the contact area between the conductive fibers and the photoconductor can be increased.

As another structure of the contact type charger, there is a magnetic brush. In general, when the diameter of the magnetic conductive particles of the magnetic brush is increased, the regulating force from the magnet roll increases, and a nip width larger than that of the charging brush, the charging blade, and the charging roller can be formed. However, as the diameter of the magnetic conductive particles increases, the area of contact with the photoconductor decreases. Therefore, there was an optimum size of the magnetic conductive particles.

As shown in FIG. 12, the shape of the magnetic conductive particles is a mixture of magnetic conductive particles 1213 having a smooth surface and magnetic conductive particles 1214 having an uneven surface (Japanese Patent Laid-Open No. 8-6355). As shown in FIG. 13, and using magnetic conductive particles having two particle size distributions (a magnetic conductive particle 1215 having a large particle size and a magnetic conductive particle 1216 having a small particle size) (JP-A-8-691491). Japanese Patent Application Laid-Open Publication No. H11-157, and an attempt has been made to increase the contact area between the photoconductor and the magnetic conductive particles while maintaining the regulating force of the magnet roll 1211 and securing a large nip width.

[0009]

In corotrons and scorotrons, corona discharge applies an electric field to the air, so that harmful substances such as ozone and NOx are generated in large quantities, and power consumption is low due to low charging efficiency. Many, 4 ~
Since a 6 kV high voltage power supply is required, there are drawbacks in that the cost is high and there is a danger to the human body. Improving such corotrons and scorotrons is urgently required due to environmental considerations in recent years, and is being shifted to a roller charging system.

However, even in the roller charging method, a voltage is applied to the minute gap between the photosensitive member and the charging roller to generate corona discharge, so that the generation of ozone cannot be reduced to zero in principle. Further, since ozone is generated near the photoconductor, deterioration of the photoconductor due to ozone still remains as a problem. Therefore, a charging method that does not generate ozone at all is strongly desired, and recently, a charge injection method has attracted attention.

However, Ja by Kagawa, Furukawa, Shinkawa et al.
pan Hardcopy '92, pp287-29
According to the report of No. 0, 80% R
At a high temperature of H, the organic photoconductor (hereinafter abbreviated as OPC) can obtain a sufficient charging voltage, but at a temperature of 30 to 50% RH, the photoconductor is charged only up to half of the applied voltage and the injection speed is low. It can be seen (see FIG. 10). This is presumably because the contact area (nip width) between the photosensitive member and the charging roller is small and the conductive rubber forming the charging roller has not been sufficiently reduced in resistance.

That is, in order to obtain a conductive rubber having a low resistance, it is necessary to dope a large amount of the charge transfer complex. However, as the doping amount increases, the flexibility of the network of the polymer itself decreases, and It is thought that the rubber hardness of the rubber may increase. For example, JP-A-6-7545
In the contact type charger described in Japanese Patent Publication No. 9 (1999), the resistance of the conductive rubber is 10 ⁶ Ω · cm, and it is necessary to reduce the resistance of the conductive rubber while maintaining an appropriate rubber hardness by selecting a polymer material. It is not expected that this will be easy.

Further, as shown in FIG. 10, in the case of a conductive rubber made of a polymer material provided with conductivity as a whole, the charging potential is sensitive to humidity, so that the environment must be strictly controlled, and It gets complicated.

In Japanese Unexamined Patent Publication No. Hei 7-140729, a charge is injected into the photosensitive member using a water-absorbing sponge roller. However, when a water-absorbing sponge roller is used,
Since the water content of the sponge roller has a great effect on the roller resistance and the charge injection speed, the charging potential may fluctuate due to evaporation of water from the sponge roller. In order to suppress the fluctuation of the charging potential, it is necessary to strictly control the evaporation of water from the sponge roller over a long period of time, and the structure of the contact charging member becomes complicated, and it cannot be manufactured at low cost.

In the contact type charger described in JP-A-9-101649, the conductive fibers 111 of the charging brush 1110 are used.
Although 2 is an etched fiber or a split fiber, the tensile strength of the split fiber is smaller than that of the fiber before splitting by the split amount. As a result, the conductive fibers
When the fiber comes into contact with the photoreceptor, the split fibers are easily cut, and if used for a long time, the charging potential varies, which causes a reduction in the life of the contact type charger. Conversely, when trying to obtain a long-life contact type charger, the number of conductive fibers cannot be increased, so a significant increase in the contact area between the conductive fibers and the photoconductor cannot be expected, and the charge injection speed is improved. Cannot be significantly improved.

JP-A-8-6355, JP-A-8-6
No. 91491 describes that the magnetic conductive particles contributing to an increase in the contact area with the photoconductor are the magnetic conductive particles 12 used.
Magnetic conductive particles 1214 having irregularities among 13 to 1216
And only the magnetic conductive particles 1216 having a small particle size,
A remarkable increase in the contact area between the magnetic conductive particles and the photoconductor could not be expected, and it was difficult to obtain a sufficient charging potential in a high-speed image recording apparatus.

According to the present invention, in the case of a contact-type charger for charging an object to be charged by charge injection, a sufficient charging voltage can be applied to the object to be charged due to a high injection speed, and environmental fluctuations such as humidity change can be provided. In addition, in the case of a contact-type charger that uses corona discharge in a minute gap with the member to be charged, generation of ozone and NOx can be reduced. It is an object of the present invention to provide a contact-type charger which can reduce the power consumption and reduce the voltage of an external power supply.

Still another object of the present invention is to provide an image recording apparatus which does not generate ozone or NOx, can reduce the voltage of the external power supply of the contact charger, and can obtain a good image. And

[0019]

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 contacts the surface of the member to be charged,
2. Description of the Related Art A contact-type charger in which a charged body is charged to a predetermined surface potential by applying a voltage to the charged body has a carbon nanotube on a surface in contact with the charged body.

According to a second aspect of the present invention, in the contact-type charger according to the first aspect, the carbon nanotubes are mainly CH = na ₁ + ma ₂ nm = 3 k a ₁ , a ₂ : a two-dimensional hexagonal lattice. Basic translation vector n, m, k: integer This is a single-walled carbon nanotube described by a chiral vector Ch of the formula:

According to a third aspect of the present invention, in the contact charger of the first aspect, the carbon nanotubes are multi-walled carbon nanotubes.

According to a fourth aspect of the present invention, there is provided the contact-type charger according to any one of the first to third aspects, comprising a charging brush, wherein the carbon nanotubes are provided on the surface of conductive fibers of the charging brush. It is.

According to a fifth aspect of the present invention, there is provided the contact-type charger according to any one of the first to third aspects, comprising a charging roller.

According to a sixth aspect of the present invention, there is provided the contact-type charger according to any one of the first to third aspects, comprising a charging blade.

According to a seventh aspect of the present invention, there is provided the contact-type charger according to any one of the first to third aspects, comprising a magnetic brush, wherein the carbon nanotubes are provided on the surface of magnetic conductive particles of the magnetic brush. It is.

According to an eighth aspect of the present invention, there is provided a contact-type charger according to any one of the first to seventh aspects.

[0027]

FIG. 1 shows an embodiment of the present invention (hereinafter referred to as Embodiment 1). In the first embodiment, a charging brush is used as a contact type charger. The charging brush 110 has a structure in which a metal core 111 and a conductive fiber 112 are connected, and a carbon nanotube 120 is connected to each conductive fiber 112. The charging brush 110 is mainly in contact with the surface of the photosensitive member 100 as a member to be charged by the carbon nanotubes 120. In a part of the nip portion, the conductive fiber 112 is directly
It does not matter even if it is in contact with the surface.

The photoreceptor 100 comprises an organic photoreceptor (OPC) comprising a drum-shaped substrate 101 made of Al and an organic photoconductive layer 102 formed on the substrate 101. A charge injection blocking layer is provided between 101 and the organic photosensitive layer 102. Charging brush 110
The metal core 111 is connected to an external DC power supply 103, a voltage is applied from the DC power supply 103, and electrons are injected directly from the carbon nanotubes 120 directly to the organic photosensitive layer 102 (that is, negatively charged charges are injected). With photoreceptor 100
Is charged. Note that some charges may be injected from the conductive fibers 112 that are in direct contact with the organic photosensitive layer 102,
Alternatively, electrons may be extracted from the carbon nanotubes 120 by field emission to charge the organic photosensitive layer 102.

In the charge injection, since the charge is directly transferred at the contact portion between the contact charger and the organic photosensitive layer, the contact area between the contact charger and the organic photosensitive layer must be increased in order to obtain a practical injection speed. Must. However, the diameter of the conductive fiber of the charging brush is generally about 10 to 20 μm, and in a high-speed image recording apparatus in which the OPC rotates at a high speed, it is necessary to ensure a sufficient contact area between the contact charger and the organic photosensitive layer. Could not. In addition, when the conductive fiber is made into an etching fiber or a split fiber, the contact area between the contact charger and the organic photosensitive layer can be increased to about several times. There was a problem that can not be converted.

The charging brush 110 of the first embodiment mainly contacts the organic photosensitive layer 102 with the carbon nanotubes 120. The carbon nanotubes include single-walled carbon nanotubes and multi-walled carbon nanotubes. As the carbon nanotubes 120, one or both of single-walled carbon nanotubes and multi-walled carbon nanotubes can be used. Single-walled carbon nanotubes vary in size depending on the catalyst, have a diameter of 0.7 to 50 nm, an axial length (hereinafter abbreviated as length) of 10 nm to 1 mm, and have a diameter of 0 to facilitate synthesis. 0.7 to 5 nm, and the length is 30 nm to 100 μm.

On the other hand, the multi-walled carbon nanotube has a diameter of 1 to 500 nm and a length of 10 nm to 1 mm,
As a size that is easier to synthesize, the diameter is 2 to 50 nm
The single-walled carbon nanotubes and the multi-walled carbon nanotubes each have a length of 1 μm or more, and have a very fine fiber shape having an extremely large aspect ratio. The size of the carbon nanotube used in the present invention is not limited to the above size range, and any carbon nanotube having a diameter of less than 1 μm is included in the present invention. Also,
Since the carbon nanotube 120 has a seamless structure, it has a very high elastic modulus and a large tensile strength in the axial direction of the tube.

Since the carbon nanotubes 120 have a very small diameter, they can be densely arranged on the conductive fibers 112 in the axial direction. Further, since the carbon nanotube 120 has a large elasticity, it can bend when it comes into contact with the organic photosensitive layer 102, and the carbon nanotube 12
The organic photosensitive layer 102 can be brought into contact not only at the leading end of the zero, but also at the side surface.

Here, the carbon nanotubes 120 are semiconductive or metallic (that is, have ohmic contact).
Since it has conductive properties, it is possible to inject charges directly from the carbon nanotubes 120 into the organic photosensitive layer 102. For this reason, in the charging brush 110 in which the carbon nanotubes 120 are connected to the conductive fibers 112, the conductive fibers 112 are formed between the organic photosensitive layer 102 and the charging brush 110 as compared with a conventional charging brush made of etching fibers and split fibers. The contact area between the organic photosensitive layer 102 and the charging brush 110 (hereinafter, referred to as a conductive contact) can be significantly increased.
As a result, the charge injection speed can be improved. Therefore, a sufficient charging voltage can be obtained even in a high-speed image recording apparatus.

Further, since the carbon nanotubes 120 have a large tensile strength in the axial direction, even if they are extremely fine, they are very unlikely to break when they come into contact with the organic photosensitive layer 102, and the charging voltage varies very long in the long term. In addition, the life of the charging brush 110 can be prolonged. As described above, the carbon nanotubes 120 exhibit semiconducting or metallic electric conductivity. However, when the carbon nanotubes 120 are used for the charging brush 110, the carbon nanotubes 120 reduce the contact resistance between the charging brush 110 and the organic photosensitive layer 102. Electrical conduction is more preferred.

FIG. 2 is a schematic view of a six-membered ring obtained by cutting out and expanding a single-walled carbon nanotube. Assuming that the basic translation vectors of the two-dimensional hexagonal lattice of the six-membered ring are a ₁ and a ₂ , the chiral vector Ch of the single-walled carbon nanotube is described as follows. Note that Ch of the single-walled carbon nanotube shown in FIG. 2 indicates (n, m) = (3, 0).

Ch = na ₁ + ma ₂ a ₁ , a ₂ : basic translation vector of a two-dimensional hexagonal lattice n, m: integer The following are already known as conditions for showing metallic conductivity in a single-walled carbon nanotube. .

Nm = 3k k: integer Therefore, the single-walled carbon nanotube is charged into the charging brush 110
When the following formulas (1) and (2) are satisfied, the contact resistance between the charging brush 110 and the organic photosensitive layer 102 can be reduced, which is more preferable.

Ch = na ₁ + ma ₂ (1) nm = 3k (2) a ₁ , a ₂ : basic translation vectors of a two-dimensional hexagonal lattice n, m, k: integers Note that (1) in FIG. , Ch that satisfies the expression (2) is indicated by ○.

On the other hand, in the case of a multi-walled carbon nanotube,
Since the interaction between the graphenes in each layer is small, the conductivity of each layer is mixed, and generally shows metallic conductivity. However, a structure more suitable for the charging brush cannot be uniquely determined. However, in the single-walled carbon nanotube, only one piece of graphene contributes to electric conduction, whereas in the multi-walled carbon nanotube, graphene of each layer contributes to electric conduction. Charge the organic photosensitive layer 102
There is an advantage that can be injected.

Next, a method for producing a carbon nanotube will be described. Single-walled carbon nanotubes are made of Fe, Co, Ni, Ru, Rh, Pd, Os,
A composite rod mixed with a metal medium such as Ir, Pt, La, or Y is used, and graphite is used as a cathode.
It is synthesized by arc discharge in an atmosphere of He or H ₂ at 700 Torr. The single-walled carbon nanotube exists in soot on the inner wall of the chamber (chamber soot) or soot on the cathode surface (cathode soot) depending on the type of the metal catalyst.

The above composite rod was placed in an electric furnace for 1 hour.
The single-walled carbon nanotubes may be synthesized by heating to 000 to 1400 ° C. and irradiating light from an Nd: YAG pulse laser in an Ar atmosphere of 500 Torr. Since the synthesized single-walled carbon nanotube contains various impurities,
It is preferable to purify to a purity of 80% or more by a hydrothermal method, a centrifugal method, an ultrafiltration method or the like.

On the other hand, for the multi-walled carbon nanotube, a graphite rod was
It synthesize | combines using the arc discharge in He atmosphere of orr.
The multi-walled carbon nanotube is located at the center of the columnar deposit on the cathode. Further, multi-walled carbon nanotubes can also be obtained by thermally decomposing hydrocarbons such as benzene, ethylene, and acetylene at 1000 to 1500 ° C. under a H ₂ gas flow.

Since multi-walled carbon nanotubes also contain various impurities after synthesis, they are dispersed in an aqueous solution to which an organic solvent or a surfactant is added, and then purified to a high purity by centrifugation or ultrafiltration. Is good. Although carbon nanotubes are generally composed of only carbon atoms,
Even if some of the constituent atoms are replaced with other atoms, for example, B, N, Si, etc., the present invention is included in the present invention as long as it has metallic or semiconductive conductivity. Also, similar atoms in hollow tubes of carbon nanotubes, such as metal atoms and II
It does not matter if a group I or group V dopant or the like is encapsulated.

The tip of the carbon nanotube may be either a closed tube or an open tube.

Next, an example of a method for manufacturing the charging brush 110 to which the carbon nanotubes are connected will be described. FIG. 3 shows an example of a method for manufacturing the charging brush 110. FIG. 3 shows a part of a cross section of the charging brush. The charging brush 110 has a columnar structure, and the conductive fibers 112 are connected to all side surfaces of the metal core 111. (A) A conductive fiber 112 is planted on a metal core 111 made of a metal or alloy such as SUS, Al, Fe, or Cu by electric flocking (see FIG. 3A). As the conductive fibers 112, conductive rayon, conductive nylon, conductive polyester, or the like having a diameter of 5 to 20 μm can be used. The density of flocking is 50 to 300 fibers / m as in a general charging brush.
It is good to about m ^2.

As a method of imparting conductivity to the fiber, there is a method of dispersing carbon black or metal fine particles in a polymer. An electron-accepting compound such as tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene ( TTF)
Alternatively, a charge transfer complex composed of an electron donating compound may be substituted with a polymer network to impart conductivity to the entire polymer fiber.

Since the conductive fiber 112 is originally used at a diameter of 5 to 20 μm, it is not necessary to maintain an appropriate elasticity unlike a conventional conductive rubber. Therefore, various polymer materials can be used, and conductive fibers having low resistance can be easily obtained. Alternatively, the conductive fiber 112 may be made into a pile ground, cut into a tape shape, and then wound around the metal core 111. (B) Then, a conductive adhesive 130 is applied to only the tip of the conductive fiber 112 with a thickness of 2 to 10 μm (see FIG. 3B), and (c) the carbon nanotubes 120 are
Is sucked into and brought into contact with the conductive fiber 112 (FIG. 3C).
(D) Thereafter, the conductive adhesive 130 is thermally cured to fix the carbon nanotubes 120, thereby completing the charging brush 110 (see FIG. 3D).

In addition, instead of the conductive adhesive 130, the conductive fibers 112 themselves are heated and the carbon nanotubes 120 are heated.
May be melted and fixed to the conductive fiber 112. After bonding the carbon nanotubes 120 to one long conductive fiber 112 with a conductive adhesive, the conductive fiber 11
2 is cut into 1 to 2 mm, and the conductive fiber 112 is planted on the metal core 111 by electric flocking to form the charging brush 11.
It may be set to 0. Further, the long conductive fibers 112 to which the carbon nanotubes 120 are bonded are made into a pile ground and cut into a tape shape.
11 to form a charging brush 110.

FIG. 4 shows another method of manufacturing the charging brush 110. FIG. 4 shows a part of a cross section of the charging brush 110. The charging brush 110 has a columnar structure, and the conductive fibers 112 are connected to all side surfaces of the metal core 111. (A) A conductive fiber 112 is planted on a metal core 111 made of a metal or alloy such as SUS, Al, Fe, or Cu by electric flocking (see FIG. 4A). In addition, the conductive fiber 11
2 is piled and cut into a tape shape.
11 may be wound. (B) After that, polymethylphenylsilane 140 is applied only to the tip of the conductive fiber 112 with a thickness of 0.1 to 3 μm (see FIG. 4B). Of polymethylphenylsilane 140
Break the Si bond (see FIG. 4 (c)). (D) Thereafter, as shown in FIG. 4D, the conductive fiber 112 is immersed in a solution (abbreviated as an IPA solution) 141 in which carbon nanotubes are dispersed in isopropyl alcohol, and the Al electrode is used as a counter electrode 142 as a metal. An external power supply 143 is connected to the core 111 and the external power supply 143 is connected to the metal core 11.
A negative voltage is applied to 1 to bring the carbon nanotubes 120 into contact with the conductive fibers 112 by electrophoresis.

The carbon nanotubes 120 move in a direction parallel to the applied electric field, and come into contact with the conductive fibers 112 to be pierced and immobilized in the polymethylphenylsilane 140 in which the Si—Si bond is broken (to be referred to as electrophoresis in the future). Abbreviated as law). In order to fix the carbon nanotubes 120 to all the conductive fibers 112 on the side surfaces of the metal core 111, the length direction of the metal core 111 may be rotated in the IPA solution 141 in the circumferential direction. (E) Thereafter, the conductive fiber 112 is pulled up from the IPA solution 141, and isopropyl alcohol is evaporated to complete the charging brush 110. Also, as described in FIG.
One long conductive fiber 112 has carbon nanotube 1
20 is fixed by electrophoresis, and then the conductive fiber 112 is cut into 1 to 2 mm.
May be planted on the metal core 111 by electric flocking to form a charging brush. Further, the long conductive fibers 112 on which the carbon nanotubes 120 are immobilized by the electrophoresis method are piled, cut into a tape shape, and the conductive fibers 112 are wound around a metal core 111 to form a charging brush 110.
It is good.

Next, the OPC 100 as a member to be charged will be described. A hole injection blocking layer in which titanium oxide fine particles are dispersed in a binder resin is formed to a thickness of 1 to 5 μm on a drum-shaped Al substrate 101 by a dip coating method, and then a charge generation layer (hereinafter abbreviated as CGL) and a charge transport layer (Hereinafter abbreviated as CTL) laminated organic photosensitive layer 1
02 was formed. CGL is a charge generation material (hereinafter CGM)
) Is dispersed in a binder resin such as a petilal resin, a thermosetting modified acrylic resin, or a phenol resin, and is formed to have a thickness of 0.1 to 1 μm by a dipping coating method.

Examples of the CGM include squarylium dyes having sensitivity at wavelengths of about 740 to 780 nm, metal-free phthalocyanine, metal phthalocyanine, azurenium salt dyes, azo pigments, and the like, and thiapyrylium salts and polycyclic quinones having sensitivity at about 635 to 650 nm. System, perylene system, azo pigment or the like can be used.

The CTL is formed by dispersing a hole carrier transport material (hereinafter abbreviated as CTM) in a binder resin such as a pisphenol-based polycarbonate resin, and has a film thickness of about 10 to 40 μm and is formed by dipping coding. CTM includes oxadiazole derivatives, pyrarizone derivatives, triphenylmethane derivatives,
Oxazole derivatives, triarylamine derivatives, butadiene derivatives and the like are used.

In this example, the OPC using holes among the carriers generated by light is used. However, CGMs generating electrons and CTMs transporting electrons have been developed, although to a small extent. OP using electrons
There is no problem even if it is C. In that case, the DC power supply 103
The positive and negative polarities are reversed so that the positive charging is performed, and the above-mentioned charging brush can be used as it is.

Although the present embodiment has been described using the function-separated type OPC as an example, the present invention is not limited to the function-separated type OPC, and may be a single-layer type OPC.
In this example, the photoconductor is a drum-shaped OPC.
Instead of the substrate 111, a belt having a conductive layer formed on the surface may be employed to form a belt-shaped OPC. Further, the photoconductor may be a sheet-like OPC. Further, the present invention is not limited to the contact type charger used for OPC,
The same contact-type charger can be used even with inorganic photosensitive members such as e-system, a-Si, ZnO, etc., and the type of the photosensitive member does not limit the contact-type charger of the present invention.

Although the present embodiment is a rotatable roll-shaped charging brush, the effects of the present invention can be similarly obtained even with a fixed brush, and the charging brush may be of any shape. Further, although the charging brush 110 is connected to the DC power supply 103, the power supply is not limited to DC, and DC and AC may be superimposed.

The charging brush 1 was actually manufactured according to the manufacturing method shown in FIG.
10 was produced. The configuration is shown below. Charging brush 110 Nip width: 3.5 mm, OPC1
Pressing into 00: 0.7 mm, peripheral speed: rotating metal core 1 in reverse direction at 4.4 times the peripheral speed of OPC 100 by driving means
11 Diameter: 10 mm, Material: SUS conductive fiber 112 Diameter: 10 μm, Length: 2 mm,
Density: 120 / mm ■, Material: Nylon fiber doped with TCNQ and TTF Carbon nanotube 120 Diameter: 10 to 25 n
m, length: 20-100 μm, material: multi-walled carbon nanotube, synthesis method: arc discharge, purification: use of centrifugal separation method and ultrafiltration method conductive adhesive 130 material: thermosetting epoxy-based conductive adhesive The charging brush 110 is connected to a DC power supply 103 of -500V.
And contacted with the OPC 100 composed of CTL / CGL / hole injection blocking layer / Al substrate to perform charging.

The peripheral speed of the OPC 100 is 300 mm /
s, the contact time between the charging brush 110 and the OPC 100 is 0.051 s. The OPC 100 was charged to -440 V while in contact with the charging brush 110, and it was confirmed that the charging brush 110 in which the carbon nanotubes 120 were connected to the conductive fibers 112 had a sufficient charging ability. The variation in the charging voltage in the longitudinal direction of the OPC 100 was within 5%, and sufficient uniformity was obtained.

FIG. 5 shows another example of the contact type charger of the present invention (hereinafter referred to as Example 2). In the second embodiment, a charging roller is used as a contact type charger. In the charging roller 510 according to the second embodiment, the metal core 511 is
The conductive rubber 512 has a structure in which carbon nanotubes 520 are implanted. The charging roller 510 mainly contacts the surface of the OPC 500 with the carbon nanotube 520. Note that a part of the conductive rubber 512 in the nip portion is OPC500.
May come into direct contact with the surface.

The OPC 500 comprises a drum-shaped substrate 501 made of Al and an organic photoreceptor (OPC) composed of an organic photoconductive layer 502 formed on the substrate 501. A charge injection blocking layer is provided between the organic photosensitive layer 502 and the organic photosensitive layer 502. Charging roller 510
The metal core 511 is connected to an external DC power supply 503, a voltage is applied from the DC power supply 503, and electrons are directly injected into the organic photosensitive layer 502 mainly from the carbon nanotubes 520 (that is, negatively charged charges are injected). OPC500
Is charged. Note that some charges may be injected from the conductive rubber 512 which is in direct contact with the organic photosensitive layer 502,
Alternatively, electrons may be extracted from the carbon nanotubes 520 by field emission to charge the organic photosensitive layer 502.

In the charging roller 510 of the second embodiment, the conductive contact between the organic photosensitive layer 502 and the charging roller 510 is made of carbon nanotubes 520. Carbon nanotubes are chemically stable because they have no dangling bonds, and have very high mechanical strength because they have a seamless structure. Therefore, the stability of the conductive contact is very good, and the charging roller using carbon nanotubes has less variation due to the environment compared to the conventional conductive rubber with the whole conductivity and the water-absorbing sponge roller. , And can maintain a stable charging ability for a long time.

Since the carbon nanotubes 520 have a very small diameter, they can be arranged densely on the conductive rubber 512. In addition, carbon nanotube 5
20 has a large elasticity and can be bent when it comes into contact with the organic photosensitive layer 502.
Can contact organic photosensitive layer 502 not only at the tip but also at the side. For this reason, in the charging roller 510 in which the carbon nanotubes 520 are connected to the conductive rubber 512, the conductive contact with the organic photosensitive layer 502 can be increased although the carbon nanotubes are not so remarkable as when used for the charging brush. Speed can be improved.

Next, an example of a method for manufacturing the charging roller 510 of the second embodiment will be described. (A) Metal core 511 made of SUS, Al, Fe, Cu
Is covered with a conductive rubber 512 by a molding method. The thickness of the conductive rubber 512 is preferably 1 to 30 mm. As a method of imparting conductivity to rubber, there is a method of dispersing carbon black or metal particles in a polymer.However, a charge transfer complex composed of an electron accepting compound and an electron donating compound is replaced with a polymer network. Conductivity may be imparted to the entire polymer. As the rubber, EPDM, polyurethane, NBR, silicone rubber and the like can be used. (B) Then, a conductive adhesive is applied to the surface of the conductive rubber 512 by a roll coater or a spray with a thickness of 1 to 2 μm. (C) Thereafter, the carbon nanotube 520 is applied to the conductive rubber using electrostatic force. Then, the conductive adhesive is thermally cured, the carbon nanotubes 520 are fixed, and the charging roller 510 is completed.

As in the first embodiment, the carbon nanotube 520 may be fixed to the conductive rubber 512 by electrophoresis to form the charging roller 510. Example 2
The charging roller 510 is connected to the DC power supply 503, but the power supply is not limited to DC, and DC and AC may be superimposed. The charging roller 510 was actually manufactured by the above manufacturing method. The configuration is shown below.

Charging roller 510 Nip width: 2.0 m
m, peripheral speed: rotated in accordance with OPC100 Metal core 511 Diameter: 10 mm, Material: SUS conductive rubber 512 Thickness: 5 mm, Material: Silicone rubber with carbon black dispersed Carbon nanotube 520 Diameter: 0.7 to 2 n
m, length: up to 20 μm, material: single-walled carbon nanotube, synthesis method: arc discharge using Fe—Ni catalyst,
Purification: ultrafiltration method conductive adhesive Material: thermosetting epoxy conductive adhesive The above charging roller 510 is supplied with a -500V DC power supply 503.
, And charged by contacting with OPC500 composed of CTL / CGL / hole injection blocking layer / Al substrate.

The peripheral speed of the OPC 500 is 150 mm /
s, the contact time between the charging roller 510 and the OPC 500 is 0.013 s. The OPC 500 was charged to -370 V while in contact with the charging roller 510, and it was confirmed that the charging roller 510 in which the carbon nanotube 520 was connected to the conductive rubber 512 had a sufficient charging ability. A similar charging test was performed at a humidity of 30 to 80% RH, but the variation of the charging voltage of OPC500 was 10%.
It was found that it was sufficiently resistant to environmental changes.

FIG. 6 shows another example of a contact-type charger of the present invention (hereinafter, referred to as a third embodiment). In the third embodiment, a charging blade is used as a contact type charger. In the charging blade 610 of the third embodiment, a conductive rubber 612 is attached to one surface of a metal plate 611, and the conductive rubber 612 is further attached.
Has a structure in which carbon nanotubes 620 are implanted. The charging blade 610 is mainly in contact with the surface of the OPC 600 by the carbon nanotube 620. Note that some of the conductive rubber 612 in the nip portion is OP
It may be in direct contact with the surface of C600.

The OPC 600 is composed of a drum-shaped base 601 made of Al and an organic photoconductor (OPC) made of an organic photosensitive layer 602 formed on the base 601. A charge injection blocking layer is provided between the organic photosensitive layer and the photosensitive layer. Charging blade 61
The 0 metal plate 611 is connected to an external DC power supply 603 and a voltage is applied from the DC power supply 603 to inject electrons directly from the carbon nanotubes 620 directly to the organic photosensitive layer 602 (that is, to inject negatively charged charges). OPC60
0 is charged. Note that some of the charges are stored in the organic photosensitive layer 602.
The organic photosensitive layer 602 may be charged by injecting electrons from the conductive rubber 612 that is in direct contact with the organic photosensitive layer 602 by extracting electrons from the carbon nanotubes 620 by field emission.

The carbon nanotube 620 has a function as a solid lubricant. Charging blade 61 of the third embodiment
0 indicates the organic photosensitive layer 602 and mainly the carbon nanotube 62
0, the charging blade 610 and the OPC6 are compared with the conventional charging blade without carbon nanotubes.
The coefficient of friction with the OPC 600 can be reduced, and in long-term use, mechanical damage such as "shave the OPC 600" and "wear the OPC 600" is less likely to occur, and the life of the OPC 600 can be improved.

Since the carbon nanotube 620 has a large elasticity, it can bend when it comes into contact with the organic photosensitive layer 602, and can contact the organic photosensitive layer 602 not only on the tip but also on the side of the carbon nanotube 620. Therefore, in the charging blade 610 in which the carbon nanotube 620 is connected to the conductive rubber 612, although not as remarkable as when used for the charging brush, the organic photosensitive layer 6
02 can be made larger, and the charge injection speed can be improved.

Next, the charging blade 610 of the third embodiment
An example of a method for fabricating is described. (A) Metal plate 611 made of SUS, Al, Fe, Cu
A conductive rubber 612 is attached to one surface of the substrate. Conductive rubber 6
The thickness of 12 is preferably 1 to 30 mm. As a method of imparting conductivity to rubber, there is a method of dispersing carbon black or metal particles in a polymer.However, a charge transfer complex composed of an electron accepting compound and an electron donating compound is replaced with a polymer network. Conductivity may be imparted to the entire polymer. As the rubber, EPDM, polyurethane, NBR, silicone rubber and the like can be used. (B) Then, a conductive adhesive is applied to the surface of the conductive rubber 612 by a roll coater or a spray to a thickness of 1 to 2 μm. (C) Then, the carbon nanotubes 620 are applied to the conductive rubber using electrostatic force. (D) After that, the conductive adhesive is thermally cured to fix the carbon nanotubes 620, thereby completing the charging blade 610.

Further, similarly to the first embodiment, the carbon nanotube 620 may be fixed to the conductive rubber 612 by electrophoresis to form the charging blade 610. The charging blade 610 can also be manufactured by the manufacturing method shown in FIG. That is, (a) the n ⁺ Si substrate 650 is immersed in a 50% HF aqueous solution, and is subjected to electric field etching while irradiating the back surface of the substrate 650 with light;
1 (see FIG. 7A). (B) Then, the substrate 650 is taken out from the HF aqueous solution,
After washing / drying, a 5 nm-thick Fe layer 652 is formed on the porous Si layer 651 by a vacuum evaporation method using an electron beam (see FIG. 7B). (C) After that, annealing is performed at 300 ° C.
2 is oxidized (see FIG. 7C). (D) Then, as shown in FIG. 7D, the substrate 651 is placed in a chemical vapor deposition (hereinafter abbreviated as CVD) apparatus 653,
C ₂ H ₂ is thermally decomposed at 700 ° C. while flowing Ar and C ₂ H ₂ , and multi-walled carbon nanotubes 620 are placed on the Fe layer 652.
Are synthesized. At this time, the multi-walled carbon nanotube 62
0 is formed vertically on the Fe layer 652. (E) The substrate 651 is taken out from the CVD device 653 as shown in FIG. On the other hand, SUS, Al, Fe, Cu
A conductive rubber 612 is attached to one surface of a metal plate 611 made of a metal or alloy such as a metal, and then a thermosetting conductive adhesive 654 is applied to the surface of the conductive rubber 612 by a spin coater in a thickness of 1 to 3 μm. . As a method of imparting conductivity to rubber, there is a method of dispersing carbon black or metal particles in a polymer.However, a charge transfer complex composed of an electron accepting compound and an electron donating compound is replaced with a polymer network. Conductivity may be imparted to the entire polymer. In addition, as rubber, EPDM, polyurethane, NBR,
Silicone rubber or the like can be used. Then, the conductive rubber 612 coated with the conductive adhesive 654 is pressed against the multi-walled carbon nanotube 620. (f) The conductive adhesive 654 is cured by heating, and the multi-walled carbon nanotube 620 is fixed to the conductive rubber 612. From the Fe layer 652 to the multi-walled carbon nanotube 620
And the charging blade 610 is completed.

Since the multi-walled carbon nanotube 620 does not adhere firmly to the Fe layer 652, the metal plate 6
11 and the substrate 650 are pulled off on both sides, and the multi-walled carbon nanotube 620 is charged with the charging blade 610.
Remains on the side. According to this manufacturing method, since the carbon nanotubes can be synthesized side by side in any direction, there is no need for purification, and the charging blade 610 can be easily obtained.

The charging blade 610 was actually manufactured according to the manufacturing method shown in FIG. The configuration is shown below. Charge blade 610 Nip width: 4.0 mm Metal plate 611 Width: 4 mm, Material: SUS conductive rubber 612 Thickness: 3 mm, Material: Polyurethane nylon carbon nanotube 620 doped with TCNQ and TTF Diameter: 14 to 18 n
m, length: up to 250 μm, material: multi-walled carbon nanotubes, synthesis method: thermal CVD method using Ar and C ₂ H ₂ , purification: none conductive adhesive material: thermosetting epoxy-based conductive adhesive The charging blade 610 is connected to a DC power source 60 of -500 V
3, CTL / CGL / hole injection blocking layer / Al
Charging was performed by contacting the substrate with OPC600.

Although the charging blade 610 in FIG. 6 is connected to the DC power supply 603, the power supply is not limited to DC, and DC and AC may be superimposed.

The peripheral speed of the OPC 600 is 200 mm /
s, the contact time between the charging blade 610 and the OPC 600 is 0.02 s. The OPC 600 was charged to -390 V while in contact with the charging blade 610, and it was confirmed that the charging blade 610 in which the carbon nanotube 620 was connected to the conductive rubber 612 had sufficient charging ability. Further, when the friction coefficient between the OPC 600 and the charging blade 610 was measured, the friction coefficient of the charging blade 610 of Example 3 was ２〜 to 1/1 according to the pressing conditions, as compared with the conventional charging blade without carbon nanotubes.
It was confirmed that it was reduced to zero.

FIG. 8 shows another example of the contact type charger of the present invention (hereinafter referred to as Example 4). In the fourth embodiment, a magnetic brush is used as a contact type charger. The magnetic brush 810 according to the fourth embodiment is a non-rotating magnet roll 811 having an S pole and an N pole as magnetic field generating means, a non-magnetic conductive sleeve 812 rotating around the magnet roll 811, and a charging member. Magnetic conductive particles 813
, And has a structure in which carbon nanotubes 820 are implanted in magnetic conductive particles 813. The magnetic brush 810 mainly includes the carbon nanotubes 82.
0 is in contact with the surface of the OPC 800. Note that some of the magnetic conductive particles 813 may be in direct contact with the surface of the OPC 800.

Next, the OPC 800 will be described. OP
C800 is a drum-shaped substrate 801 made of Al;
It is composed of an organic photoconductor (OPC) comprising an organic photosensitive layer 802 formed on the substrate 801, and a charge injection blocking layer is provided between the substrate 801 and the organic photosensitive layer 802 as necessary. Conductive sleeve 8 of magnetic brush 810
12 is connected to an external DC power source
3, a voltage is mainly applied to the carbon nanotubes 82
The OPC 800 is charged by injecting electrons directly from 0 into the organic photosensitive layer 802 (that is, injecting negatively charged charges). Note that some charges may be injected from the magnetic conductive particles 813 which are in direct contact with the organic photosensitive layer 802, or electrons may be extracted from the carbon nanotubes 820 by field emission to charge the organic photosensitive layer 802. Absent.

In the magnetic brush 810 of the fourth embodiment, the conductive contact between the organic photosensitive layer 802 and the magnetic brush 810 is made of carbon nanotubes 820. Since the carbon nanotube 820 has a very small diameter, the magnetic conductive particles 81
3 can be densely arranged. In addition, since the carbon nanotube 820 has large elasticity, it can bend when it comes into contact with the organic photosensitive layer 802, and can contact the organic photosensitive layer 802 not only at the tip but also at the side of the carbon nanotube 820. Therefore, in the magnetic brush 810 in which the carbon nanotubes 820 are connected to the magnetic conductive particles 813, the conductive contact with the organic photosensitive layer 802 can be significantly increased as compared with the conventional magnetic conductive particles, and the charge injection speed is greatly improved. it can.

Further, since the diameter of the magnetic conductive particles 813 has almost no influence on the size of the conductive contact, it can be determined in consideration of only the magnetic force of the magnet roll 811. As a result, the nip width can be increased while keeping the conductive contacts large, and the charge injection speed can be further improved.

Next, an example of a method for manufacturing the magnetic brush 810 of the fourth embodiment will be described. (A) A conductive adhesive is applied to the surface of magnetic conductive particles 813 made of a metal or alloy such as Fe, Co, Ni or the like by spraying to a thickness of 1 to 2 μm, and (b) thereafter, using electrostatic force, The carbon conductive particles 81
(C) heat-curing the conductive adhesive to fix the carbon nanotubes 820 to the magnetic conductive particles 813; and (d) a conductive sleeve 812 made of non-magnetic SUS surrounding the magnet roll 811. Is brought into contact with the magnetic conductive particles 813 completed in (c) to complete the magnetic brush 810.

The size of the magnetic conductive particles 813 is preferably 5 to 100 μm as in a general magnetic brush. Further, the carbon nanotubes 820 may be fixed to the magnetic conductive particles 813 by an electrophoresis method. Further, the carbon nanotubes 820 may be fixed to the magnetic conductive particles 813 by the manufacturing method shown in FIG. (A) A Ni layer 860 is formed by sputtering on the surface of magnetic conductive particles 813 made of a metal or alloy such as Fe, Co, and Ni (see FIG. 9A). (B) Thereafter, as shown in FIG. 9 (b), plasma enhanced hot filament CVD (hereinafter PE-HF-C)
VD) The magnetic conductive particles 813 are placed in a device 861,
Ni layer 8 by plasma etching while flowing NH ₃
The thickness of 60 is set to 40 nm or less. (C) Thereafter, as shown in FIG. 9 (c), C ₂ H ₂ and N ₂ are flowed to generate plasma at 700 ° C. or lower to synthesize carbon nanotubes 820. Note that the carbon nanotubes 820 grow vertically from the magnetic conductive particles 813. (D) Then, as shown in FIG. 9 (d), PE-HF-C
The carbon nanotube 820 is taken out from the VD device 861.

According to this manufacturing method, the carbon nanotubes 820 can be synthesized in a state of being directly bonded to the magnetic conductive particles 813. Therefore, the step of purifying the carbon nanotubes 820 and the step of bringing the magnetic conductive particles 813 into contact with the carbon nanotubes 820 are omitted. The magnetic brush 810 can be obtained easily. The magnetic brush 81 shown in FIG.
Although 0 is connected to the DC power supply 803, the power supply is not limited to DC, and AC may be superimposed on DC.

The magnetic brush 810 was actually manufactured by the manufacturing method shown in FIG. The configuration is shown below.

Magnetic brush 810 Nip width: 5.0 m
m, circumferential speed: OPC800 rotary magnet roll 811 flux density in a direction opposite to the at twice the peripheral speed OPC800 of: 800 × 10 ^{- 4}
T (on the conductive sleeve 812) Conductive sleeve 812 Diameter: 20 mm, Material: SUS Magnetic conductive particles 813 Diameter: 10 to 20 μm, Material:
Fe—Co alloy carbon nanotube 820 diameter: about 100 nm,
Length: about 20 μm, Material: Multi-walled carbon nanotube, Synthesis method: PE-HF-CVD using C ₂ H ₂ and N ₂
Method, purification: none The above magnetic brush 810 was connected to a DC power supply 803 of -500V.
, And was contacted with OPC800 composed of CTL / CGL / hole injection blocking layer / Al substrate to perform charging.

The peripheral speed of the OPC 800 is 300 mm /
s, the contact time between the magnetic brush 810 and the OPC 800 is 0.033 s. The OPC 800 was charged to -470 V while in contact with the magnetic brush 810, and it was confirmed that the magnetic brush 810 in which the carbon nanotubes 820 were connected to the magnetic conductive particles 813 had sufficient charging ability. The variation in the charging voltage in the longitudinal direction of the OPC 800 was within 5%, and sufficient uniformity was obtained.

Next, another embodiment (hereinafter referred to as a fifth embodiment) of an image recording apparatus according to the present invention will be described. In the fifth embodiment, each of the contact-type chargers 11 manufactured in the first to fourth embodiments is used.
0, 510, 610, 810 and -500V DC power supply 1
03, 503, 603, and 803 were mounted as a charging system in an image recording apparatus including an electrophotographic copying machine, and a test chart was copied. Note that the developing device used was a developing device that performs low-potential development (black and white binary development), and the gradation was indicated by the number of dots.

Here, in the copying machine according to the fifth embodiment, the drum type OPC is rotated by the driving means, and
After the OPC is uniformly charged by the contact type chargers of Nos. 1 to 4, the OPC is exposed by the exposure device to form an electrostatic latent image, and the electrostatic latent image on the OPC is developed by the developing device to form a toner. It becomes an image. The toner image on the OPC is transferred to a transfer material such as transfer paper fed from a paper feeding device by a transfer unit, the toner image on the transfer material is fixed by a fixing device, and the transfer material is discharged to the outside. .

As a reference, a copying machine equipped with a power supply of 5 kV and a corotron as a charging system was used. This reference did not perform low potential development because the charging voltage was 800 V, and the gradation was displayed in analog. As a result of copying by the copying machine of Example 5, all good images were obtained. In particular, when the charging brush 110 according to the first embodiment and the magnetic brush 810 according to the fourth embodiment are used, more gradations can be displayed than the image obtained by the reference copying machine, and the resolution is improved.

The image obtained when the charging roller 510 according to the second embodiment and the charging blade 610 according to the third embodiment are mounted is the image obtained when the charging brush 110 according to the first embodiment and the magnetic brush 810 according to the fourth embodiment are used. The slight deterioration compared to the image obtained in the above was due to low potential development,
It is estimated that an equivalent image will be obtained when the potential is further reduced in the future.

Further, in the copying machine of the fifth embodiment equipped with the contact type charger of the first to fourth embodiments, almost no ozone or NOx was detected during the charging process of the photosensitive member. Therefore,
In the embodiment of the copying machine equipped with the contact type charger of the present invention,
It has been confirmed that good image recording can be performed without generating ozone or NOx and while reducing the voltage of the external power supply of the charging system. In addition, when life tests were performed on all the copying machines of Example 5 equipped with the contact-type chargers of Examples 4 to 4, good images were obtained over a long period of time. The long-term reliability was found to be excellent. In addition, the frequency of replacement of the contact chargers of Examples 1 to 4 could be reduced.

Further, in all the copying machines of the fifth embodiment equipped with the contact chargers of the first to fourth embodiments, the contact chargers are O
The PC was hardly scraped, and the life of the OPC was significantly extended as compared with a copying machine equipped with a conventional charging roller or charging blade. Considering the above results, if the production cost of carbon nanotubes can be reduced in the future, there is a possibility that the total cost of the copying machine can be reduced. It should be noted that similar effects can be expected to be obtained by applying the present invention to an image recording apparatus such as a printer or a facsimile.

Next, another embodiment of the present invention (hereinafter referred to as Embodiment 6)
Will be described. The contact-type charger of the sixth embodiment is different from the contact-type charger of the second embodiment in that a voltage equal to or higher than the discharge starting voltage Vth is applied to the minute gap between the carbon nanotube 520 and the OPC 500.

In Examples 1 to 5, charging was performed mainly by charge injection. Generally, a large charging voltage (600
(V to 1 kV), the OPC is charged mainly by corona discharge in a minute gap between the OPC and the contact type charger. Also in the contact-type charger, when a voltage equal to or higher than the discharge starting voltage Vth is applied to the minute gap between the carbon nanotube and the OPC, corona discharge occurs in the minute gap between the OPC and the contact-type charger, and OPC occurs. Be charged. In particular, since the carbon nanotube has an extremely fine needle shape, the uneven electric field at the tip of the carbon nanotube becomes strong, and Vth can be reduced.

The carbon nanotube 5 of Example 6 was actually
20 is Vt at charging roller 510 in contact with OPC 500
When h was measured, it was confirmed that Vth was lower than Vth of the charging roller without carbon nanotubes. Therefore, when the OPC is charged using corona discharge at the tip of the carbon nanotube, the applied voltage can be reduced as compared with the conventional roller charging method (charging method using corona discharge using a charging roller).

Further, the corona discharge in the minute gap causes O
When the ozone and NOx generated when charging the PC were measured, the charging roller connected with the carbon nanotube generated less ozone and NOx than the conventional charging roller without the carbon nanotube. This is presumably because corona discharge occurs only at the tip of the carbon nanotube, and the discharge space is small and the applied voltage is small in the charging roller to which the carbon nanotube is connected, so that the generation of ozone and NOx is suppressed.

Therefore, the charging roller in which the carbon nanotube is connected to the tip of the charging member is charged with O 2 by corona discharge.
Even when the PC is charged, there are advantages such as reduction of ozone and NOx and reduction of the voltage of the external power supply. In the sixth embodiment, a charging roller is used. In the charging brushes, charging blades, and magnetic brushes of the first, third, and fourth embodiments, the discharge starting voltage V
A similar effect can be obtained by applying a voltage equal to or greater than th.

As described above, the present invention is not limited to charging methods such as charge injection, electric field emission, and corona discharge in a minute space, but is applicable to all contact-type chargers including the structure of the present invention. can do. Further, in the above embodiment, the charging brush, the charging roller, the charging blade, and the magnetic brush are used. However, the present invention is not limited to the shape of the above embodiment, and the present invention is not limited to the shape of the charging member. All contact-type chargers with connected nanotubes are included.

[0099]

As described above, according to the first aspect of the present invention, the member to be charged comes into contact with the carbon nanotube. When an object to be charged is charged by charge injection, the carbon nanotubes have an extremely small diameter, so that the carbon nanotubes can be densely arranged on the contact surface with the object to be charged. When it comes into contact with the charged body, it can bend, can contact the charged body not only at the tip of the carbon nanotube, but also on the side face, and can substantially increase the contact area between the contact type charger and the charged body,
The charge injection speed can be improved. As a result, a sufficient charging voltage can be applied to the member to be charged.

When the object to be charged is charged by corona discharge in a minute gap between the object to be charged and the contact-type charger, the carbon nanotube has an extremely fine needle shape. The unequal electric field becomes stronger, and the firing voltage can be reduced. Therefore, compared to the conventional roller charging method, the applied voltage can be reduced and the corona discharge space can be reduced. As a result, ozone and NOx generated in the discharge space can be reduced.

Further, since the carbon nanotube has a large tensile strength in the axial direction, even if it is extremely fine, it is very unlikely to break when it comes into contact with the member to be charged. The service life of the contact charger can be extended.

According to the second aspect of the invention, the carbon nanotubes are mainly composed of CH = na ₁ + ma ₂ nm = 3 k a ₁ , a ₂ : basic translation vectors of a two-dimensional hexagonal lattice n, m, k: integers Since the single-walled carbon nanotube is described by the chiral vector Ch of the following formula, the single-walled carbon nanotube has metallic conductivity and can reduce the contact resistance between the contact-type charger and the member to be charged. As a result, more efficient charge injection becomes possible.

According to the third aspect of the present invention, since the carbon nanotubes are multi-walled carbon nanotubes, they have substantially metallic conductivity, and graphene of each layer constituting the multi-walled carbon nanotube contributes to electric conduction. More charges can be injected into the member to be charged.

According to the fourth aspect of the present invention, there is provided a charging brush having carbon nanotubes on the surface of conductive fibers. Since carbon nanotubes have an extremely small diameter, they are densely arranged on the conductive fibers in the axial direction. Is possible.
Also, since carbon nanotubes have great elasticity,
When the carbon nanotube comes into contact with the member to be charged, it can bend, and can contact the member to be charged not only at the tip but also at the side surface of the carbon nanotube. Therefore, the contact area between the charged body and the charging brush can be significantly increased as compared with the conventional charging brush in which the conductive fibers are made of the etching fiber and the split fiber. As a result, the speed of charge injection can be improved.

According to the fifth aspect of the present invention, the conductive contact point between the member to be charged and the charging roller is made of carbon nanotubes. Since carbon nanotubes have no dangling bonds, they are chemically stable. Very strong mechanical strength due to seamless structure. As a result, the stability of the conductive contacts is very good, and compared to conventional conductive rubber that has been given overall conductivity and a water-absorbing sponge roller, there is less fluctuation due to the environment and stable charging over a long period of time. Can maintain ability.

Further, since the carbon nanotube has an extremely small diameter, it can be densely arranged on a conductive rubber or the like. In addition, since the carbon nanotube has a large elasticity, it can bend when it comes into contact with the member to be charged, and can contact the member to be charged not only at the tip but also on the side surface of the carbon nanotube. Therefore, the conductive contact point with the member to be charged can be increased, and the charge injection speed can be improved.

According to the sixth aspect of the present invention, the object to be charged mainly comes into contact with the carbon nanotube, and the carbon nanotube has a function as a solid lubricant. It can reduce the coefficient of friction between the charging blade and the member to be charged, and is less likely to cause mechanical damage such as "shaving the member to be charged" and "wearing the member to be charged" during long-term use, and the life of the member to be charged. Can be improved. Further, since the carbon nanotube has a large elasticity, it can bend when it comes into contact with the member to be charged, and can contact the member to be charged not only at the tip but also on the side surface of the carbon nanotube. Therefore, the conductive contact point with the member to be charged can be increased, and the charge injection speed can be improved.

According to the seventh aspect of the present invention, the magnetic conductive particles have carbon nanotubes on their surfaces, and the carbon nanotubes have an extremely small diameter, so that the carbon nanotubes can be densely arranged on the magnetic conductive particles. In addition, since the carbon nanotube has a large elasticity, it can bend when it comes into contact with the member to be charged, and can contact the member to be charged not only at the tip but also on the side surface of the carbon nanotube. Therefore, compared with the conventional magnetic conductive particles, the conductive contact with the member to be charged can be significantly increased, and the charge injection speed can be improved. In addition, since the diameter of the magnetic conductive particles hardly affects the size of the conductive contact, it can be determined by considering only the magnetic force of the magnetic field generating means. As a result, the nip width can be increased while keeping the conductive contacts large, and the charge injection speed can be further improved.

According to the invention of claim 8, claims 1 to 1 are provided.
7, the charged object is charged by charge injection, and the charged object is charged by corona discharge in a minute gap between the charged object and the contact type charger. However, a sufficient charging voltage can be applied to the member to be charged, and a good image can be obtained by continuing the development. In particular, when a charging brush or a magnetic brush is mounted, an image having excellent gradation can be obtained.

When the charged object is charged by charge injection, no ozone or NOx is generated during the charging process. When the charged object is charged by corona discharge in a minute gap, the corona discharge space can be reduced. In addition, ozone and NOx generated in the discharge space can be reduced. In addition, since the charging efficiency is improved in both of the respective methods of charging the charged object by charge injection and corona discharge in the minute gap, the voltage of the external power supply for charging mounted on the image recording apparatus can be reduced. Furthermore, the long-term reliability of the contact charger is improved, and the life of the member to be charged, especially the OPC, is extended, so that the frequency of replacement of the contact charger and the member to be charged, especially the OPC can be reduced. Therefore, in the future, there is a possibility that the total cost of the image recording apparatus can be reduced by further reducing the production cost of the carbon nanotube.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a six-membered ring of a single-walled carbon nanotube.

FIG. 3 is a view showing an example of the manufacturing method of the first embodiment.

FIG. 4 is a view showing another example of the manufacturing method of the first embodiment.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a view showing an example of the manufacturing method of the third embodiment.

FIG. 8 is a sectional view showing a fourth embodiment of the present invention.

FIG. 9 is a view showing an example of a method for producing the magnetic conductive particles of Example 4 described above.

FIG. 10 is a diagram showing characteristics showing a relationship between an applied voltage and a charging voltage of a conventional conductive rubber roller.

FIG. 11 is a sectional view showing a conventional charging brush.

FIG. 12 is a sectional view showing a conventional magnetic brush.

FIG. 13 is a sectional view showing another conventional magnetic brush.

[Explanation of symbols]

100, 500, 600, 800 OPC 103, 503, 603, 803 DC power supply 110 Charging brush 111, 511 Metal core 112 Conductive fiber 120, 520, 620, 820 Carbon nanotube 510 Charging roller 512 Conductive rubber 610 Charging blade 611 Metal Plate 612 Conductive rubber 810 Magnetic brush 811 Magnet roll 812 Conductive sleeve 813 Magnetic conductive particles

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[Procedure amendment]

[Submission date] February 9, 2000 (200.2.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, in the contact-type charger according to the first aspect, the carbon nanotubes are mainly Ch = na ₁ + ma ₂ nm = 3 k a ₁ , a ₂ : a two-dimensional hexagonal lattice. Basic translation vector n, m, k: integer This is a single-walled carbon nanotube described by a chiral vector Ch of the formula:

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction contents]

FIG. 2 is a schematic view of a six-membered ring obtained by cutting out and expanding a single-walled carbon nanotube. Assuming that the basic translation vectors of the two-dimensional hexagonal lattice of the six-membered ring are a ₁ and a ₂ , the chiral vector Ch of the single-walled carbon nanotube is described as follows. Note that Ch of the single-walled carbon nanotube shown in FIG. 2 indicates (n, m) = (3, 0).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

Ch = na ₁ + ma ₂ a ₁ , a ₂ : basic translation vector of a two-dimensional hexagonal lattice n, m: integer The following are already known as conditions for showing metallic conductivity in a single-walled carbon nanotube. .

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

Ch = na ₁ + ma ₂ (1) nm = 3k (2) a ₁ , a ₂ : basic translation vectors of a two-dimensional hexagonal lattice n, m, k: integers (1) in FIG. Ch that satisfies the equation (2) is indicated by a circle .

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction contents]

Since multi-walled carbon nanotubes also contain various impurities after synthesis, they are dispersed in an aqueous solution to which an organic solvent or a surfactant is added, and then purified to a high purity by centrifugation or ultrafiltration. Is good. Although carbon nanotubes are generally composed of only carbon atoms,
Even if some of the constituent atoms are replaced with other atoms, for example, B, N, Si, etc., the present invention is included in the present invention as long as it has metallic or semiconductive conductivity. Also, other atoms such as metal atoms and II
It does not matter if a group I or group V dopant or the like is encapsulated.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

Further, instead of the conductive adhesive 130, the conductive fibers 112 themselves may be heated and the carbon nanotubes 120 may be fused and fixed to the conductive fibers 112. Also,
One long conductive fiber 112 has carbon nanotube 1
After adhering 20 with a conductive adhesive, the conductive fibers 112 may be cut into 1 to 2 mm, and the conductive fibers 112 may be planted on the metal core 111 by electric flocking to form the charging brush 110. Further, the long conductive fiber 112 to which the carbon nanotubes 120 are bonded is made into a pile ground and cut into a tape shape.
May be wound as a charging brush 110.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction contents]

FIG. 4 shows another method of manufacturing the charging brush 110. FIG. 4 shows a part of a cross section of the charging brush 110. The charging brush 110 has a columnar structure, and the conductive fibers 112 are connected to all side surfaces of the metal core 111. (A) A conductive fiber 112 is planted on a metal core 111 made of a metal or alloy such as SUS, Al, Fe, or Cu by electric flocking (see FIG. 4A). In addition, the conductive fiber 11
2 is piled and cut into a tape shape.
11 may be wound. (B) Then, (see FIG. 4 (b)) a polymethylphenylsilane 140 only at the distal end of the conductive fiber 112 is coated with a thickness of 0.1 to 3 m, (c) Thereafter, the order of the wavelength 400nm by ultra-high pressure mercury lamp Irradiate the light of polymethylphenylsilane 140
Break the -Si bond (see FIG. 4C). (D) Thereafter, as shown in FIG. 4D, the conductive fiber 112 is immersed in a solution (abbreviated as an IPA solution) 141 in which carbon nanotubes are dispersed in isopropyl alcohol, and the Al electrode is used as a counter electrode 142 as a metal. An external power supply 143 is connected to the core 111 and the external power supply 143 is connected to the metal core 11.
A negative voltage is applied to 1 to bring the carbon nanotubes 120 into contact with the conductive fibers 112 by electrophoresis.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

[0053] CTL becomes a carrier transporting material of a hole (hereinafter referred to as CTM) from those dispersed in a binder resin such as bisphenol-based polycarbonate resin, a film thickness was formed by dipping the coding method in the order of 10 to 40 [mu] m. CTM includes oxadiazole derivatives, pyrarizone derivatives, triphenylmethane derivatives,
Oxazole derivatives, triarylamine derivatives, butadiene derivatives and the like are used.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Change

[Correction contents]

The charging brush 1 was actually manufactured according to the manufacturing method shown in FIG.
10 was produced. The configuration is shown below. Charging brush 110 Nip width: 3.5 mm, OPC1
Pressing into 00: 0.7 mm, peripheral speed: rotating metal core 1 in reverse direction at 4.4 times the peripheral speed of OPC 100 by driving means
11 Diameter: 10 mm, Material: SUS conductive fiber 112 Diameter: 10 μm, Length: 2 mm,
Density: 120 strands / mm ² , Material: nylon fiber doped with TCNQ and TTF Carbon nanotube 120 Diameter: 10 to 25 n
m, length: 20-100 μm, material: multi-walled carbon nanotubes, synthesis method: arc discharge, purification: conductive adhesive 130 used in combination with centrifugal separation method and ultrafiltration method material: thermosetting epoxy-based conductive adhesive The charging brush 110 is connected to a DC power supply 103 of -500V.
And contacted with the OPC 100 composed of CTL / CGL / hole injection blocking layer / Al substrate to perform charging.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Change

[Correction contents]

Charging roller 510 Nip width: 2.0 m
m, peripheral speed: rotated in accordance with OPC100 Metal core 511 Diameter: 10 mm, Material: SUS conductive rubber 512 Thickness: 5 mm, Material: Silicone rubber with carbon black dispersed Carbon nanotube 520 Diameter: 0.7 to 2 n
m, length: up to 20 μm , material: single-walled carbon nanotubes, synthesis method: arc discharge using Fe-Ni catalyst, purification: ultrafiltration method conductive adhesive material: thermosetting epoxy conductive adhesive Charging roller 510 with a -500 V DC power supply 503
, And charged by contacting with OPC500 composed of CTL / CGL / hole injection blocking layer / Al substrate.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

The charging blade 610 was actually manufactured according to the manufacturing method shown in FIG. The configuration is shown below. Charge blade 610 Nip width: 4.0 mm Metal plate 611 Width: 4 mm, Material: SUS conductive rubber 612 Thickness: 3 mm, Material: Polyurethane nylon carbon nanotube 620 doped with TCNQ and TTF Diameter: 14 to 18 n
m, length: maximum 250 μm, material: multi-walled carbon nanotubes, synthesis method: thermal CVD method using Ar and C2H2, purification: none conductive adhesive material: thermosetting epoxy conductive adhesive The above charging blade 610 To a -500V DC power supply 60
3, CTL / CGL / hole injection blocking layer / Al
Charging was performed by contacting the substrate with OPC600.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

The size of the magnetic conductive particles 813 is preferably 5 to 100 μm as in a general magnetic brush. Further, the carbon nanotubes 820 may be fixed to the magnetic conductive particles 813 by an electrophoresis method. Further, the carbon nanotubes 820 may be fixed to the magnetic conductive particles 813 by the manufacturing method shown in FIG. (A) A Ni layer 860 is formed by sputtering on the surface of magnetic conductive particles 813 made of a metal or alloy such as Fe, Co, and Ni (see FIG. 9A). (B) Thereafter, as shown in FIG. 9 (b), plasma enhanced hot filament CVD (hereinafter PE-HF-C)
VD) The magnetic conductive particles 813 are placed in a device 861,
Ni layer 8 by plasma etching while flowing NH3
The thickness of 60 is set to 40 nm or less. (C) Thereafter, as shown in FIG. 9 (c), C2H2 and N2 are flowed to generate a plasma at 700 ° C. or lower to synthesize carbon nanotubes 820. Note that the carbon nanotubes 820 grow vertically from the magnetic conductive particles 813. (D) Then, as shown in FIG. 9 (d), PE-HF-C
The carbon nanotubes 820 are connected from the VD device 861.
The continued magnetic conductive particles 813 are taken out.

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0087

[Correction method] Change

[Correction contents]

Next, another embodiment (hereinafter referred to as a fifth embodiment) of an image recording apparatus according to the present invention will be described. In the fifth embodiment, each of the contact-type chargers 1 manufactured in the first to fourth embodiments is used.
10, 510, 610, 810 and -500 V DC power supplies 103, 503, 603, 803 are mounted as charging systems in an image recording apparatus including an electrophotographic copying machine,
A copy of the test chart was made. Note that the developing device used was a developing device that performs low-potential development (black and white binary development), and the gradation was indicated by the number of dots.

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0091

[Correction method] Change

[Correction contents]

Further, in the copying machine of the fifth embodiment equipped with the contact type charger of the first to fourth embodiments, almost no ozone or NOx was detected during the charging process of the photosensitive member. Therefore,
In the embodiment of the copying machine equipped with the contact type charger of the present invention,
It has been confirmed that good image recording can be performed without generating ozone or NOx and while reducing the voltage of the external power supply of the charging system. When it was life tested copier all examples 5 equipped with a contact type charger of Examples 1 to 4, good images can be obtained over a long period of time, Examples 1 to 4
It was found that the long-term reliability of the contact type charger was excellent. In addition, the frequency of replacement of the contact chargers of Examples 1 to 4 could be reduced.

[Procedure amendment 16]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

In Examples 1 to 5, charging was performed mainly by charge injection. Generally, a large charging voltage (600
(V to 1 kV), the OPC is charged mainly by corona discharge in a minute gap between the OPC and the contact type charger. Also in the contact charger of the present invention ,
When a voltage equal to or higher than the discharge starting voltage Vth is applied to the minute gap between the carbon nanotube and the OPC, corona discharge occurs in the minute gap between the OPC and the contact-type charger, and the OPC occurs.
Is charged. In particular, since the carbon nanotube has an extremely fine needle shape, the uneven electric field at the tip of the carbon nanotube becomes strong, and Vth can be reduced.

[Procedure amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0102

[Correction method] Change

[Correction contents]

[0102] According to the invention according to claim 2, mainly carbon nanotube _{Ch = na 1 + ma 2 n} -m = 3k a 1, a 2: primitive translation vectors n of the two-dimensional hexagonal lattice, m, k: integer Since the single-walled carbon nanotube is a single-walled carbon nanotube described by the chiral vector Ch in the following formula, the single-walled carbon nanotube has metallic conductivity and can reduce the contact resistance between the contact-type charger and the member to be charged. As a result, more efficient charge injection becomes possible.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuichi Hikiji 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Company Limited (72) Inventor Tadashi Fujimura 1-3-6 Nakamagome, Ota-ku, Tokyo・ Within Ricoh Co., Ltd. (72) Inventor Kiman Nakayama 1-14-2, Karigaoka, Hirakata-shi, Osaka 404 F-term (reference) 2H003 AA18 BB11 CC04 CC05 CC06 3J103 AA02 AA51 AA72 FA30 GA02 GA33 GA52 GA57 GA58 GA60 HA04 HA19 HA20 HA22

Claims (8)

[Claims] 1. A contact-type charger which contacts a surface of a member to be charged and charges the member to be charged to a predetermined surface potential by applying a voltage to the member to be charged. A contact-type charger characterized by having nanotubes. 2. The contact-type charger according to claim 1, wherein said carbon nanotubes are mainly composed of CH = na ₁ + ma ₂ nm = 3 k a ₁ , a ₂ : a basic translation vector n, m of a two-dimensional hexagonal lattice. , K: a single-walled carbon nanotube described by a chiral vector Ch of the following formula: 3. A contact-type charger according to claim 1, wherein said carbon nanotube is a multi-walled carbon nanotube. 4. A contact-type charger according to claim 1, comprising a charging brush, wherein said carbon nanotubes are provided on the surface of conductive fibers of said charging brush. Charger. 5. The contact-type charger according to claim 1, comprising a charging roller. 6. A contact-type charger according to claim 1, comprising a charging blade. 7. A contact-type charger according to claim 1, comprising a magnetic brush, wherein said carbon nanotubes are present on the surface of magnetic conductive particles of said magnetic brush. Charger. 8. An image recording apparatus comprising the contact-type charger according to claim 1.