JP2001281964A - Contact type electrifier, its manufacturing method, and image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact type electrifier capable of applying a sufficient electrification voltage on a photoreceptor, because an electric charge is quickly injected, and also, which is satisfactorily durable against the environmental fluctuation such as humidity, etc., and also, where the fluctuation of the electrifi cation voltage is reduced irrespective of a long time use, as for the contact type electrifier for electrifying the photoreceptor by injecting the electric charge. SOLUTION: An electrifying brush 110 is manufactured by electrically flocking an electrifying brush main body 124 as a rubbing-electrifying member on the outer peripheral surface of a metal core bar 111. The electrifying brush main body 124 (bristles of the electrifying brush 110) is constituted by arranging carbon-nano-tubes 120 as conductive fiber members in the conductive fiber 123. In this case, carbon black 122 as conductive particles and the carbon-nano- tubes are mixed and dispersed in base resin for spinning, and after spinning the base resin, the surface of the spun fiber, that is, the surface of the conductive fiber 123 is machine-ground, and then, the longitudinal carbon-nano-tube is made to partly project from the conductive fiber 123.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type charger for an image recording apparatus such as an electrophotographic copying machine, a printer and a facsimile, a method for manufacturing the same, and an image recording apparatus equipped with the contact type charger. It is.

[0002]

2. Description of the Related Art A conventional charging method uses a corona discharge.
Corotron and scorotron were the mainstream. Only
Corona discharge applies an electric field in the air,
Or NO _XHarmful substances such as
Low power efficiency, high power consumption, and high power of 4-6 kV
High voltage and high risk due to need of voltage power supply
There was a drawback that there is. Distribution to recent environment
Improving such charging system is urgently needed.
Is shifting to roller charging.

FIG. 11 is a schematic cross-sectional view showing a conventional contact charger 1110 (charging roller, that is, a conductive rubber roller). In this figure, reference numeral 1100 denotes an organic photoconductor (OPC), reference numeral 1101 denotes an Al base, and reference numeral 110 denotes
2 is an organic photosensitive layer. Reference numeral 1103 denotes a DC power supply, reference numeral 1111 denotes a cored bar, and reference numeral 1124 denotes a conductive rubber (sliding charging member).

FIG. 12 shows a conventional contact type charger 2110.
FIG. 3 is a schematic cross-sectional view showing a (charging brush). In this figure, reference numeral 2100 denotes an organic photoconductor (OPC), and reference numeral 210 denotes
Reference numeral 1 denotes an Al substrate, and reference numeral 2102 denotes an organic photosensitive layer. Reference numeral 2103 denotes a DC power supply, reference numeral 2111 denotes a cored bar, and reference numeral 2124 denotes a conductive brush (charging brush body: rubbing charging member).

[0005] Roller charging is a method in which a conductive rubber roller is brought into contact with a photoreceptor, a discharge is generated in a minute gap between the photoreceptor and the charging roller, and the surface of the photoreceptor is charged. The generation amount is significantly reduced (reduced to 1/100 to 1/500).

However, since the charging roller applies a voltage to the minute gap between the photosensitive member and the charging roller to cause corona discharge, the amount of ozone generated 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.

The charge injection method is a method in which charges are directly injected from a contact-type charger into a photosensitive layer without causing discharge. Therefore, ozone is not generated in principle. In charge injection, the lower the contact resistance, the better the contact resistance between the contact-type charger and the photoreceptor and the capacity of the minute voids affect the injection speed at the time of charge injection.

[0008] Therefore, in the technique described in JP-A-6-75459, tetracyanoquinodimethane (TCN) is used.
Q) and an electron accepting compound such as tetrathiafulvalene (T
A charge roller is made of a conductive rubber made of a polymer material having conductivity provided by replacing a charge transfer complex composed of an electron donating compound such as TF) with a polymer network.

However, J by Kagawa, Furukawa, and Shinkawa et al.
apan Hardcopy '92, pp. 287-2
According to the report of No. 90, an organic photoreceptor (hereinafter sometimes abbreviated as OPC) can obtain a sufficient charging voltage under a high humidity of 80% RH, but only up to half the applied voltage under a humidity of 30 to 50% RH. It is not charged, indicating that the injection speed is low. This is presumably because the contact area (nip width) of the charging roller is small and the resistance of the conductive rubber is not sufficiently reduced.

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 (the rubber hardness increases). As a result, it is considered that the above-mentioned contact area is reduced. For example, in JP-A-6-75459, the resistance of the conductive rubber is one.
0 has a ⁶ Omega · cm, to reduce the resistance of the conductive rubber while maintaining a moderate rubber hardness, it is not believed to be easy in terms of the choice of polymeric material. In addition, as described above, the conductive potential of a conductive rubber made of a polymer material having conductivity as a whole is sensitive to humidity, so the environment must be strictly controlled, and the structure of the contact-type charger is complicated. become.

On the other hand, in Japanese Patent Application Laid-Open No. Hei 7-140729, electric charges are injected into a photoreceptor using a water-absorbing sponge roller. When a water-absorbing sponge roller is used, the water content of the roller has a large effect on the roller resistance and the charge injection speed, so that the charging potential may fluctuate due to evaporation of water from the roller. In order to suppress the fluctuation of the charging potential, it is necessary to strictly control the evaporation of water from the roller over a long period of time. However, this makes the structure of the contact-type charger complicated and cannot be manufactured at low cost.

Japanese Patent Application Laid-Open No. Hei 9-101649 discloses that the contact area between the conductive fiber and the photosensitive member is increased by using the conductive fiber of the charging brush as an etching fiber or a split fiber, and the charge injection speed is reduced. It has been proposed to improve. The etching fiber is a fiber obtained by dissolving a part of the component of the conductive fiber in a chemical solution and separating one conductive fiber into a plurality of pieces in the thickness direction. In addition, 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 these treatments, the conductive fibers having a substantially smaller diameter are used, and the contact area with the photoconductor can be increased.

[0013] However, the tensile strength of the separated or split fiber is compared with that of the conductive fiber before separation or split,
It becomes lower by the amount of separation and division. As a result, when the fibers come into contact with the photoreceptor, the fibers are easily cut, and when used for a long time, the charging potential varies, which causes a reduction in the life of the contact type charger. Conversely, even if a long-life contact charger is to be obtained, a significant increase in the contact area cannot be expected because the number of conductive fibers cannot be separated and divided, and it is difficult to significantly increase the charge injection speed. is there.

[0014]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a contact type charger which solves the above-mentioned problems of the prior art.
An object of the present invention is to provide a manufacturing method thereof and an image recording apparatus equipped with the contact type charger. That is, in a contact-type charger that charges a photoconductor by charge injection, a sufficient charging voltage is given to the photoconductor because of a high injection speed,
Another object of the present invention is to provide a contact-type charger which has sufficient resistance to environmental fluctuations such as humidity and the like, and has a small fluctuation of charging voltage in long-term use.

[0015] In the contact type charger utilizing corona discharge in a minute gap between the photosensitive member, contact type charging device, can reduce the occurrence of ozone and NO _X, and can realize low voltage of the external power supply It is to provide a contact type charger.

Further, the contact charging member is missing due to the rubbing,
An object of the present invention is to provide an image recording apparatus capable of preventing charging unevenness due to wear, stably charging and maintaining the same.

[0017]

According to the first aspect of the present invention, there is provided a contact-type charger including a rubbing charging member, wherein the rubbing charging member is brought into rubbing contact with the surface of the photoreceptor. In a contact-type charger that applies a potential difference between the photosensitive members to give a predetermined surface potential to the photoreceptor, the rubbing and charging member includes a conductive member and a fibrous member having conductivity, and has the conductivity. The fibrous member is formed on at least a part of the conductive member, and has one end held inside the conductive member and the other end protruding outside from the surface of the conductive member. .

According to a second aspect of the present invention, there is provided a contact-type charger comprising the metal core according to the first aspect, a large number of conductive fibers provided on the surface of the metal core, and the fibrous member. A charging brush provided with a rubbing charging member, wherein one end of the fibrous member is held inside the conductive fiber and the other end protrudes outside from the surface of the conductive fiber. .

According to a third aspect of the present invention, there is provided the contact-type charger according to the second aspect, wherein the conductive fiber has a multilayer structure, and the fibrous member is held only by the outermost layer. .

A contact-type charger according to a fourth aspect is a charging roller comprising a metal core and a rubbing charging member covering a surface of the metal core according to the first aspect. It is characterized by comprising a conductive rubber as a conductive member and the fibrous member held by the conductive rubber.

According to a fifth aspect of the present invention, in the fourth aspect, the conductive rubber has a multilayer structure, and the fibrous member is held only by the outermost layer. .

According to a sixth aspect of the present invention, there is provided a contact-type charger comprising a metal plate and a blade-shaped slidable charging member attached to one end of the metal plate.
The rubbing charging member includes a blade-shaped conductive rubber as the conductive member and the fibrous member held by the conductive rubber.

According to a seventh aspect of the present invention, in the contact type charger according to the sixth aspect, the conductive rubber has a multilayer structure, and the fibrous member is held only by the outermost layer. .

The contact-type charger according to claim 8 is characterized in that, in any one of claims 1 to 7, the fibrous member is a carbon nanotube.

According to a ninth aspect of the present invention, in the contact type charger according to the eighth aspect, the carbon nanotube is a single-walled carbon nanotube represented by a chiral vector (Ch) of the following mathematical expressions (1) and (2). It is characterized by.

[0026]

(Equation 2)

In the above equations (1) and (2), a
1 and a2 denote basic translation vectors of a two-dimensional hexagonal lattice, and n, m and k denote integers.

[0028] A contact-type charger according to a tenth aspect is characterized in that, in the eighth aspect, the carbon nanotube is a multi-walled carbon nanotube.

[0029] A method for manufacturing a contact-type charger according to claim 11 is the method for manufacturing a contact-type charger according to any of claims 8 to 10, wherein the conductive material to hold carbon nanotubes is provided. After dispersing the carbon nanotubes in the member, a step of mechanically polishing the surface of the conductive member to project the carbon nanotubes from the surface of the conductive member to the outside is provided.

According to a twelfth aspect of the present invention, there is provided an image recording apparatus including the contact-type charger according to any one of the first to tenth aspects.

[0031]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described with reference to an embodiment shown in the drawings. <Embodiment 1> FIG. 1A is a schematic cross-sectional view showing the structure of a contact type charger (charging brush) 110, and FIG. 1B is a schematic diagram of a charging brush main body 124 as the rubbing charging member. FIG.

In the charging brush 110, the metal core 111
And the charging brush main body 124 are connected. The charging brush main body 124 (bristles of the charging brush 110) includes conductive fibers 123 serving as the conductive member and carbon nanotubes 120 serving as the conductive fibrous member.
And has a structure in which the carbon nanotubes 120 protrude from the inner surface of the conductive fiber 123 to the surface. The conductive fiber 123 is obtained by dispersing conductive fine particles such as carbon black 122 in a polymer fiber to impart conductivity. This will be described later. Then, in the charging brush main body 124, mainly the carbon nanotubes 120 come into contact with the surface of the OPC 100. In some cases, the conductive fibers 123 may be in direct contact with the surface of the OPC 100.

The OPC 100 is a drum-shaped Al substrate 1
01 and the organic photosensitive layer 102, and A
A charge injection blocking layer is provided between the substrate 101 and the organic photosensitive layer 102. The metal core 111 of the charging brush 110 is connected to an external DC power supply 103 and charges the OPC 100 mainly by directly injecting electrons (that is, negatively charged charges) from the carbon nanotubes 120 into the organic photosensitive layer 102. Has become. Note that a part of the charge may be injected from the conductive fiber 123 which is in direct contact with the organic photosensitive layer 102, or the organic photosensitive layer 102 may be charged by extracting electrons from the carbon nanotubes 120 by field emission. .

The carbon nanotubes 120 are classified into single-walled carbon nanotubes and multi-walled carbon nanotubes. The single-walled carbon nanotubes differ in size depending on the catalyst, have a diameter of 0.7 to 50 nm, and have an axial length (hereinafter referred to as length). Abbreviated) is 10 nm to 1 mm, and the more easily synthesized size is 0.7 to 5 nm in diameter and 30 nm to length.
100 μm. On the other hand, the multi-walled carbon nanotube has a diameter of 2 to 500 nm, a length of 10 nm to 1 mm, and a size that is more easily synthesized has a diameter of 4 to 50 nm.
The length is 500 nm or more. Each of the single-walled carbon nanotube and the multi-walled carbon nanotube has an extremely fine shape having an extremely large aspect ratio.

The size of the carbon nanotube 120 is not limited to the above range, and any carbon nanotube having a diameter of less than 1 μm is included in the present invention. Further, since the carbon nanotube 120 has a seamless structure, it has a very high elastic modulus and a high tensile strength in the tube axis direction. Since the carbon nanotube 120 has a very small diameter, the conductive fiber 1
23 can be densely arranged.

Since the carbon nanotubes 120 have semiconducting or metallic (that is, ohmic contact) conductive properties, charges can be directly injected from the carbon nanotubes 120 into the organic photosensitive layer 102. Therefore, the carbon nanotubes 120
In the charging brush 110, the area in which the conductive fibers can transfer and receive electric charges between the organic photosensitive layer 102 and the charging brush 110, that is, substantially, The contact area (hereinafter referred to as a conductive contact) can be significantly increased, and 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 high tensile strength in the axial direction, even if they are extremely fine, they are very unlikely to break upon contact with the organic photosensitive layer 102, and in the long term, there is very little variation in charging voltage. Life can be extended.

As described above, carbon nanotubes exhibit semiconductive or metallic electrical conductivity.
0, the charging brush 110 and the organic photosensitive layer 10
In order to reduce the contact resistance of No. 2, metallic electric conduction is more preferable. In the present invention, the conductive fibrous member is not limited to the carbon nanotube, and may be any member having the same shape and characteristics as the carbon nanotube.

FIG. 2 is a schematic explanatory view showing a six-membered ring obtained by cutting out and expanding a single-walled carbon nanotube. The chiral vector Ch of the single-walled carbon tube is described as the following equation (1).

[0039]

(Equation 3)

In the above equation (1), a1 and a2
Represents a basic translation vector of a two-dimensional hexagonal lattice, and n and m represent integers.

The above Ch of the single-walled carbon nanotube of FIG. 2 indicates (n, m) = (3,0). It has been found that the condition for the single-walled carbon nanotube to exhibit metallic conductivity is that the following equation (2) is satisfied.

[0042]

(Equation 4)

In the above equation (2), n, m and k
Represents an integer.

Therefore, when the single-walled carbon nanotube is used for the charging brush 110, it is more preferable to satisfy both of the expressions (1) and (2) since the contact resistance between the charging brush and the organic photosensitive layer can be reduced. In FIG. 2,
Ch that satisfies the above equations (1) and (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 the conductivity is generally metallic, but a structure more suitable for the charging brush cannot be uniquely determined. However, in single-walled carbon nanotubes, only one piece of graphene contributes to electric conduction, whereas in multi-walled carbon nanotubes, graphene in each layer contributes to electric conduction. Charge the organic photosensitive layer 10
2 has the advantage that it can be injected. The single-walled carbon nanotube refers to a single-walled graphene (one sheet), and the multi-walled carbon nanotube refers to a single-walled graphene.

Next, a method for producing a carbon nanotube will be described. Single-walled carbon nanotubes are made of Fe, Co, Ni, Ru, Rh,
Using a composite rod mixed with a metal catalyst such as Pd, Os, Ir, Pt, La, Y, etc., a graphite rod as a cathode, and a pressure of 100 to 700 Torr (1.33 ×
It is synthesized by an arc discharge in a He or H ₂ atmosphere of 10 ^{4 to} 9.31 × 10 ⁴ Pa). Depending on the type of metal catalyst, single-walled carbon nanotubes are soot on the inner wall of the chamber (chamber soot) or soot on the cathode surface (cathode soot)
Exists in

Further, the above-mentioned composite rod was heated to 1000 to 1400 ° C. in an electric furnace, and the pressure was 500 Torr.
Nd: YA in an Ar atmosphere (6.65 × 10 ⁴ Pa)
The single-walled carbon nanotube may be synthesized by irradiating a G pulse laser beam. Since the synthesized single-walled carbon nanotube contains various impurities, it is preferable to purify it to a purity of 80% or more by a hydrothermal method, a centrifugal separation method, an ultrafiltration method, or the like.

On the other hand, the multi-walled carbon nanotube is an anode,
A graphite rod is used for the cathode and the pressure is 100 to 700T.
Synthesis is performed using arc discharge in a He atmosphere of orr (1.33 × 10 ^{4 to} 9.31 × 10 ⁴ Pa). The multi-walled carbon nanotube is located at the center of the columnar deposit on the cathode. It 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. Multi-walled carbon nanotubes also contain various impurities after synthesis, so it is better to disperse them in an organic solvent or an aqueous solution to which a surfactant is added, and then purify them to high purity by centrifugation or ultrafiltration. . The tip of the carbon nanotube may have either a closed tube or an open tube shape.

Next, FIG. 3A shows an example of a method for manufacturing the charging brush 110 in which the charging brush main body 124 is provided on the metal core 111. FIG. 3B is a schematic longitudinal sectional view of the charging brush main body 124. The charging brush 110 has a columnar structure, and the charging brush main body 124 is uniformly connected over the entire outer peripheral surface of the metal core 111.

The carbon nanotubes 120 are dispersed,
The conductive fiber 12 whose part in the longitudinal direction protrudes from the surface.
3 is made of SUS, Al, F
3 and a metal core 111 made of a metal or alloy such as e, Cu, etc.
As shown in (a), planting is performed by electric flocking. As the conductive fiber 123, conductive rayon, conductive nylon, conductive polyester, or the like having a diameter of 5 to 20 μm can be used. The flocking density is 50-
It is good to set it to about 300 lines / mm ² .

As a method for producing the conductive fiber 123 by imparting conductivity to the fiber, as shown in FIG. 3B, conductive fine particles such as carbon black 122 and metal fine particles are added to a polymer fiber. However, it is desirable to use carbon-based fine particles having good slidability. In order to produce the charging brush main body 124, the conductive fine particles are dispersed in the fiber-forming raw material, and at the same time, carbon nanotubes having been purified to a high purity are blended and dispersed in a desired blending ratio, followed by spinning. By mechanically polishing the surface of the fiber obtained by spinning, a part of the dispersed carbon nanotubes in the longitudinal direction is projected from the fiber surface. As another method of projecting carbon nanotubes, using oxygen plasma ashing or the like, ashing a base material such as rayon, nylon, or a polymer material such as polyester,
A method in which the carbon nanotubes protrude from the fiber surface can also be adopted.

These processes may be carried out as a spinning process, or after the spinning, a treatment such as polishing or oxygen plasma ashing may be carried out. The polishing process is a method using free abrasive grains, specifically, cerium oxide,
The above fibers are sandwiched between pads of urethane or the like, and 1 to 50
A load of 0 g / cm ² is applied, and alumina having a particle size of 1 μm is supplied during the application, and the fiber is pulled out from one side and polished. Depending on the winding speed (drawing speed) of the fiber, the pad is used in a single step or in a combination of a plurality of steps arranged diagonally.

In the case of dispersing the carbon nanotubes in the fiber, an example using a carbon nanotube purified to a high degree of purity has been described, but a carbon nanotube mixed with a carbon nanoparticle synthesized by an arc discharge method or the like may be used. As another method, tetracyanoquinodimethane (T
A charge transfer complex composed of an electron accepting compound such as CNQ) and an electron donating compound such as tetrathiafulvalene (TTF) may be substituted for the polymer network to impart conductivity to the entire polymer fiber. At this time, highly purified carbon nanotubes are simultaneously dispersed and spun. After spinning, the carbon nanotubes are projected from the fiber surface as described above.

[0054] In either method, the dispersion amount of the carbon nanotube surface protruding density is desirable that the amount corresponding to 0.01 present / [mu] m ² or more, be blended in an amount of the one / [mu] m ² or more, Stable charging is possible. In this embodiment, the dispersion amount of the carbon nanotube is set to 2 wt%.

FIGS. 4 and 5 show the charging brush body 12 respectively.
FIG. 4 is a schematic vertical sectional view showing another example of the structure of FIG. The charging brush main body 124 of FIG. 4 has the conductive fiber 123a as a core,
It has a sheath / core structure with the conductive fiber 123b on the outer peripheral side as a sheath. The conductive fiber 123b is obtained by dispersing carbon black 122, metal fine particles, and carbon nanotubes 120 in the fiber. Conductive fiber 123
For a, conductive rayon, conductive nylon, conductive polyester, or the like having a diameter of 2 μm to 10 μm is used.
In 23b, carbon nanotubes were dispersed in the same material, such as conductive rayon, conductive nylon, and conductive polyester, and the conductive fibers 123a and 123b were subjected to composite spinning to form fibers having a double structure. The thickness of the layer (the above-mentioned sheath) in which the carbon nanotubes are dispersed is 0.
1 μm to 10 μm.

Next, the OPC 100 will be described. A hole injection blocking layer in which titanium oxide fine particles are dispersed in a binder resin is formed on the drum-shaped Al substrate 101 to a thickness of 1 to 5 μm by a dip coating method,
Thereafter, a stacked organic photosensitive layer 102 composed of a charge generation layer (hereinafter abbreviated as CGL) and a charge transport layer (hereinafter abbreviated as CTL).
Was formed.

CGL is a charge generation material (hereinafter abbreviated as CGM) of butyral resin, thermosetting modified acrylic resin,
It is made of a material dispersed in a binder resin such as a phenol resin, and has a thickness of 0.
It was formed in a thickness of 1 to 1 μm. As CGM, the wavelength 740 to
Squarylium dyes having sensitivity around 780 nm, metal-free phthalocyanine, metal phthalocyanine, azulenium salt dyes, azo pigments, and the like, and 635-650 n
m sensitive thiapyrylium salts and polycyclic quinones,
A perylene type or an azo pigment type can be used.

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

The OPC of this example is an OPC that uses holes among carriers generated by light, but CGM that generates electrons and CTM that transports electrons have been developed to some extent. Of these, any OPC using electrons may be used. In this case, the positive and negative DC power supplies are used in reverse, and the DC power supply is used with positive charging. However, the above-described charging brush can be used as it is.

In this embodiment, the description has been made by taking the function-separated type OPC as an example. However, the present invention is not limited to the function-separated type, but may be a single-layer type OPC. This example is a drum-shaped OPC, but instead of an Al substrate, a belt having a conductive layer formed on the surface is employed.
It may be a belt-shaped OPC. OPC in sheet form
But it is good. Further, the present invention is not limited to the contact type charger used for the OPC, but includes Se-based, a-Si, Zn
The same contact type charger can be used even with an inorganic photoreceptor such as O, so the type of the photoreceptor is not limited in the present invention.

In this embodiment, the charging brush in the form of a roll has been described. However, the effects of the present invention can be similarly realized with a fixed brush, and the shape of the charging brush is not limited. In addition, although the charging brush 110 in FIG. 1 is connected to the DC power supply 103, the power supply is not limited to DC, and DC and AC may be superimposed.

A charging brush was manufactured according to the manufacturing method shown in FIG. The configuration is shown below.・ Charging brush: Nip width: 3.5 mm, pushing into OPC: 0.7 mm Circumferential speed: Rotate in the opposite direction at 4.4 times the peripheral speed of OPC ・ Metal core: Diameter: 10 mm, Material: SUS Conductive fiber: Diameter: 10 μm, Length: 2 mm, Density: 120 / mm ² Material: Nylon fiber with 2 wt% blended carbon nanotube and carbon fine particles dispersed ・ Carbon nanotube: Diameter: 10 to 25 nm, Length: 0 Material: multi-walled carbon nanotubes Synthetic method: arc discharge, purification: combined use of centrifugal separation method and ultrafiltration method

The charging brush was connected to a DC power supply of -500 V, and was brought into contact with OPC composed of CTL / CGL / hole injection blocking layer / Al substrate to perform charging. In addition, OPC
Is 300 mm / s, the contact time between the charging brush and the OPC is 0.051 s. The OPC was charged to -440 V while in contact with the charging brush, and it was confirmed that the charging brush in which the carbon nanotubes were connected to the conductive fibers had a sufficient charging ability. The variation in the charging voltage in the longitudinal direction of the OPC was within 5%, and sufficient uniformity was obtained.

Embodiment 2 FIG. 6 is a schematic cross-sectional view showing the structure of a contact type charger (charging roller) 510. In the charging roller 510, the metal core 511 is covered with the charging roller main body 524 as the rubbing charging member. The charging roller body 524 has a structure in which carbon nanotubes 520 are dispersed in an annular conductive rubber 523, and the carbon nanotubes 520 are projected from the surface of the conductive rubber 523 by polishing or the like. It is desirable that the protrusion length is controlled in the range of 0.1 μm to 400 μm by controlling the amount of polishing of the surface of the conductive rubber 523, but it is sufficient if the protrusion length is 0.2 μm to 5 μm. Further, as the charging roller body 524,
The carbon nanotube 520 is contained in a part of the conductive rubber 523 and has a structure in which the carbon nanotubes are densely packed in the surface layer, a structure in which the carbon nanotubes are uniformly contained from the surface layer to the inside, and a content density gradient from the surface layer to the inside. A structure having a given structure can be used, but a structure in which the surface layer is uniformly dense and a structure in which the material is uniformly contained from the surface layer to the inside are desirable. Due to these structures, there is an advantage that new carbon nanotubes protrude from the inside even if the conductive fibers are worn.

The amount of dispersion of the carbon nanotubes is preferably such that the surface protrusion density is at least 0.01 / μm ^2, and if the amount is at least 1 / μm ^2, stable charging is possible. is there. In this embodiment, the dispersion amount of the carbon nanotube is set to 2 wt%.

The charging roller main body 524 is mainly in contact with the surface of the OPC 500 by the carbon nanotube 520. Note that a portion of the conductive rubber 523 may directly contact the surface of the OPC 500. The OPC 500 includes a drum-shaped Al substrate 501 and an organic photosensitive layer 502, and a charge injection blocking layer is provided between the Al substrate 501 and the organic photosensitive layer 502 as necessary. The metal core 511 of the charging roller 510 is connected to an external DC power supply 503, and mainly the carbon nanotubes 520 to the organic photosensitive layer 5
OPC 500 is charged by directly injecting electrons into 02 (that is, injecting negatively charged charges). In addition, a part of the electric charge is applied to the conductive rubber 52 in direct contact with the organic photosensitive layer 502.
3, and electrons are extracted from the carbon nanotubes by field emission.
02 may be charged.

The organic photosensitive layer 502 and the charging roller 51
Zero conductive contacts are formed of carbon nanotubes 520. The carbon nanotubes 520 have no dangling bonds, are chemically stable, and have a very high mechanical strength due to their seamless structure. Therefore, the stability of the conductive contact is very good, and when using this to form the charging roller, compared to the conventional conductive rubber or water-absorbing sponge roller that has been given overall conductivity,
The fluctuation due to the environment is small, and a stable charging ability can be maintained for a long time.

Since the carbon nanotube 520 has great elasticity, it can bend when it comes into contact with the organic photosensitive layer 502, and can contact the organic photosensitive layer 502 not only at the tip but also at the side of the carbon nanotube 520. Therefore, in the charging roller 510 in which the carbon nanotube 520 is blended with the conductive rubber 523,
Although not so remarkable as in the case of the charging brush, the organic photosensitive layer 502
Can be made larger, and the charge injection speed can be improved.

Next, an example of a method for manufacturing the charging roller 510 will be described. SUS, Al, Fe or C
The metal core 511 made of u was covered with a conductive rubber 523 in which carbon nanotubes 520 were dispersed in rubber by a molding method. The thickness of the conductive rubber 523 is 1 to 30 m.
m is good. Thereafter, the surface of the conductive rubber 523 was roughly ground by cylindrical grinding, and the rough ground surface was polished with alumina abrasive grains or the like. Polishing process, particle size 10μm → 5
μm → 1 μm and change the roller surface (conductive rubber 5
23 surface), and the carbon nanotubes were projected from the surface of the charging roller 510. This protrusion length is
The thickness was controlled to 0.2 μm to 5 μm by controlling the polishing amount. The rubber for the conductive rubber 523 is EP
DM, polyurethane, NBR, silicone rubber and the like can be used. The charging roller 510 in FIG.
The power supply is not limited to DC, but DC and AC may be superimposed.

A charging roller was manufactured according to the above-described manufacturing method. The configuration is shown below.・ Charging roller: Nip width: 2.0 mm, peripheral speed: driven by OPC ・ Metal core: Diameter: 10 mm, material: SUS ・ Conductive rubber: thickness: 5 mm, Material: carbon nanotube and carbon Silicone rubber with black dispersion ・ Carbon nanotubes ... Diameter: 0.7-2 nm, length: max. 20 μm Material: Single-walled carbon nanotube Synthesis method: Arc discharge using Fe-Ni catalyst Purification: Ultrafiltration method

The above charging roller was connected to a DC power supply of -500 V, and CTL / CGL / hole injection blocking layer / Al
It was charged by contacting with an OPC made of a substrate. Note that O
Since the peripheral speed of the PC is 150 mm / s, the charging roller and O
The contact time of the PC is 0.013 s.

OPC is -3 during contact with the charging roller.
It was confirmed that the charging roller charged to 70 V and having the conductive rubber connected to the carbon nanotubes had sufficient charging ability. A similar charging test was conducted at a humidity of 30% to 80% RH. The variation of the charging voltage was within 10%, and it was found that the charging voltage was sufficiently resistant to environmental changes.

FIG. 7A is a schematic cross-sectional view showing another example of the structure of the charging roller. FIG. 7B is a partially enlarged view of FIG. 7A and shows the structure of a charging roller main body that is a sliding contact member of the charging roller. The charging roller 510 is formed by coating the outer periphery of a metal core 511 with an inner layer of conductive rubber 523a.
23a has a two-layer structure in which an outer layer of conductive rubber 523b is coated on the outer periphery. In the conductive rubber 523b, the carbon nanotubes 520 are dispersed in the conductive rubber, and the carbon nanotubes 520 protrude from the roller surface by polishing or the like. Also in this case, the dispersion amount of the carbon nanotubes 520 in the conductive rubber 523b is the same as in the above-described example, and the thickness of the conductive rubber 523b is 1 μm to 50 μm.
0 μm, particularly preferably in the range of 20 μm to 100 μm.

A method for manufacturing the charging roller 510 will be described. First, SUS, Al, Fe or Cu
Is covered with a conductive rubber 523a by a molding method. Then, the conductive rubber 523a
A conductive rubber 523b in which carbon nanotubes 520 were dispersed in the same rubber as the conductive rubber 523a was coated thereon by a molding method. The thickness of the conductive rubber 523b is preferably 1 to 30 mm. Thereafter, the surface was roughly ground by cylindrical grinding, and the surface was further polished with alumina abrasive grains or the like. In the polishing process, the roller surface was polished by changing the particle size from 10 μm → 5 μm → 1 μm, and the carbon nanotubes 520 were projected from the roller surface. The protrusion length was set to 0.2 μm to 5 μm by controlling the polishing amount.

FIG. 7B shows the structure of the carbon nanotube 52.
0 is an enlarged sectional view of the conductive rubber 523a in which the carbon nanotubes 520 are dispersed.
20 project from the roller surface to the outside. In addition,
The direction of the protrusion is not particularly specified.

<Embodiment 3> FIG. 8A is a schematic front sectional view of a charging blade 610 as a contact charger.
(B) is a side sectional view thereof. This charging blade 61
In the case of 0, a charging blade main body 624 as a rubbing charging member is attached to one surface of the metal plate 611. In the charging blade main body 624, the carbon nanotubes 620 are dispersed in the conductive rubber 623, and the carbon nanotubes 620 protrude outside from the blade (conductive rubber 623) surface by polishing or the like. Then, the charging blade body 62
Reference numeral 4 denotes mainly a carbon nanotube 620 which is in contact with the surface of the OPC 600. Note that a part of the conductive rubber 623 may directly contact the surface of the OPC 600.

The OPC 600 is a drum-shaped Al substrate 6
01 and an organic photosensitive layer 602, and A
A charge injection blocking layer is provided between the substrate 601 and the organic photosensitive layer 602. The metal plate 61 of the charging blade 610
Reference numeral 1 denotes an OPC 600 which is connected to an external DC power supply 603 and injects electrons directly from the carbon nanotubes 620 into the organic photosensitive layer 602 (ie, negatively charged charges).
Is charged. In addition, a part of the electric charge is transferred to the organic photosensitive layer 60.
Alternatively, the organic rubber layer 602 may be injected from the conductive rubber 612 which is in direct contact with the organic photosensitive layer 602, and electrons may be extracted from the carbon nanotubes by field emission to charge the organic photosensitive layer 602.

The carbon nanotube 620 has a function as a solid lubricant. Since the charging blade 610 is in contact with the organic photosensitive layer 602 mainly by the carbon nanotube 620, the friction coefficient between the charging blade 600 and the OPC can be reduced as compared with the conventional charging blade without the carbon nanotube, and the When using "OPC
It is less likely to cause mechanical damage such as “shave 600” and “wear the OPC 600”, so that the life of the OPC 600 is improved. In addition, since the carbon nanotube 620 has 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 at the tip but also at the side surface of the carbon nanotube 620. Therefore, in the charging blade 610 in which the carbon nanotube 620 is connected to the conductive rubber 623,
Although not so remarkable as when used for a charging brush, the conductive contact with the organic photosensitive layer 602 can be increased, and the charge injection speed can be improved.

Next, an example of a method for manufacturing the charging blade 610 of the present invention will be described. A conductive rubber 623 is provided on one surface of a metal plate 611 made of SUS, Al, Fe or Cu.
Paste. The thickness of the conductive rubber 623 is 1 to 3
0 mm is good. As a method of imparting conductivity to rubber,
A method of dispersing carbon black or metal fine particles in a polymer, or a method of substituting a charge transfer complex composed of an electron accepting compound and an electron donating compound with a polymer network to impart conductivity to the entire polymer. Can be adopted. In addition, EPDM, polyurethane, NBR, silicone rubber and the like can be used as the rubber.

FIG. 9 is a schematic side sectional view showing another example of the charging blade 610. In the charging blade 610, the conductive rubber 623 has a triangular side cross-sectional shape and an edge at its tip. The same effect can be obtained if the side cross-sectional shape of the blade is a trapezoid, a rhombus, an ellipse, a pentagon, or the like in addition to the square in FIG. 8B and the triangle in FIG.

FIG. 10A shows still another charging blade 6.
10 is a schematic front sectional view, and FIG. 10B is a side sectional view thereof. The charging blade 610 is provided on the metal plate 61.
1 has a double structure in which a conductive rubber 623a is provided on one side and a conductive rubber 623b is provided thereon. The conductive rubber 623a and the conductive rubber 623b constitute the rubbing charging member. In the conductive rubber 623b, the carbon nanotubes 620 are dispersed in the conductive rubber 623, and the carbon nanotubes 620 protrude from the surface of the conductive rubber 623 by polishing or the like. Again,
The dispersion amount of the carbon nanotubes 620 is the same as in the above-described example, and the thickness of the conductive layer 623b is 1 μm to 500 μm.
m, particularly preferably in the range of 20 μm to 100 μm. The charging blade 610 in FIG.
However, the power supply is not limited to the DC power supply, and DC and AC may be superimposed.

The charging blade shown in FIG. 8A was manufactured under the following conditions. -Charging blade: Nip width: 4.0 mm-Metal plate: Width: 4 mm, material: SUS-Conductive rubber: Thickness: 3 mm Material: Silicone rubber with carbon nanotube and carbon black dispersed-Carbon nanotube … Diameter: 0.7-2 nm, length: maximum 20 μm Material: single-walled carbon nanotube Synthesis method: arc discharge using Fe-Ni catalyst Purification: ultrafiltration method

The charging blade was connected to a DC power supply of -500 V, and was brought into contact with an OPC composed of CTL / CGL / hole injection blocking layer / Al substrate to perform charging. Note that OP
Since the peripheral speed of C is 200 mm / s, the charging blade and OP
The contact time of C is 0.02 s. The OPC was charged to -390 V while in contact with the charging blade, and it was confirmed that the charging blade in which the carbon nanotube was connected to the conductive rubber had a sufficient charging ability. Further, when the friction coefficient between the OPC and the charging blade was measured, the friction coefficient of the charging blade of the present invention was 1/2 to that of the conventional charging blade without carbon nanotube depending on the conditions of the pressing pressure.
It was confirmed that it was reduced to 1/10.

<Embodiment 4> Each of the contact type chargers manufactured in Embodiments 1 to 3 and a -500 V DC power supply are mounted as a charging system of an electrophotographic copying machine, and a test chart is copied. Was. The development was performed by low potential development (binary development of black and white), and the gradation was indicated by the number of dots. The reference used a power supply of 5 kV and a copying machine mounted as a corotron. Since the charging voltage of the reference was 800 V, low potential development was not performed, and the gradation was displayed in analog.

As a result of performing copying with a copying machine on which the contact-type chargers of Examples 1 to 3 were mounted, good images were obtained in all cases.
In particular, when the charging brush was used, it was possible to display more gradations than the image obtained by the reference copying machine, and the resolution was improved. The reason that the image of the copying machine equipped with the charging roller and the charging blade was slightly deteriorated as compared with the image obtained with the charging brush is due to the low potential development, and the development will be further reduced in the future. In this case, it is estimated that an equivalent image is obtained. Further, in the copying machine loaded with the contact type charger of Examples 1 to 3, ozone and NO _X was detected almost in the photosensitive member charging process.

[0086] Thus, it equipped with the copier contact type charger of the present invention, without generating ozone and NO _X, and the external power supply of the charging system with low voltage, it is confirmed that enables good image recording Was. In addition, when a life test was performed on all copying machines, it was found that good images were obtained over a long period of time, and that the long-term reliability of the contact-type charger was excellent. In addition, the replacement frequency of the contact type charger could be reduced. Further, in all the copying machines, the contact type charger was hardly observed to scrape the OPC, and the life of the OPC was significantly extended as compared with the conventional copying machine equipped with a charging roller and a charging blade.

From the above results, there is a possibility that the total cost of the copying machine can be reduced if the production cost of carbon nanotubes is reduced in the future. The same effect can be expected in an image recording apparatus such as a printer and a facsimile.

<Embodiment 5> In Embodiments 1 to 3, charging was mainly performed by charge injection. Generally, when a large charging voltage (about 600 V to 1 kV) is required, O
The charging of the PC is mainly performed by corona discharge in a minute gap between the photosensitive member and the contact type charger. Also in the contact-type 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 carbon nanotube and the OPC, and the OPC is charged. Is done. 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.

When _Vth was measured with the charging roller in contact with the carbon nanotubes of Example 2, 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 (discharge method using corona discharge using a charging roller). In addition, OPC is performed by corona discharge in micro voids.
Measurement of the ozone and NO _X that occurs when charging the charging roller which carbon nanotubes are connected was less ozone and NO _X than conventional charging roller without carbon nanotubes. This is because a corona discharge occurs only at the tip of the carbon nanotube, and the charging roller connected to the carbon nanotube has a small discharge space and a small applied voltage, so that ozone or NO
_It is considered that the generation of _X was suppressed.

Accordingly, even when the OPC is charged by corona discharge, ozone or N
Reduction or O _X, low voltage of the external power supply can be advantageously implemented. In this embodiment, the description has been made using the charging roller. However, the same effect can be obtained with a charging brush and a charging blade.

As described above, the present invention is not limited to charging methods such as charge injection, field emission, and corona discharge in a minute gap, but refers to all contact-type chargers including the structure of the present invention. ing. In the embodiments, the shapes of the charging brush, the charging roller, and the charging blade have been described.However, the present invention is not limited to the shapes of the embodiments, and the present invention includes a carbon nanotube connected to the tip of the charging member. And all contact-type chargers.

[0092]

In the contact type charger according to the first, second, fourth and sixth aspects of the present invention, the rubbing charging member includes a conductive member and a conductive fibrous member, and the fibrous member is provided. Is formed on at least a part of the conductive member, and has one end held inside the conductive member and the other end protruding outside from the surface of the conductive member. For this reason, according to this contact type charger, the contact area between the rubbing charging member and the photoreceptor can be increased, the charge injection speed is increased, and a sufficient charging voltage can be applied to the photoreceptor. Become. Further, in this contact-type charger, the fibrous member is held inside the conductive member, so that the fibrous member is not easily detached from the conductive member due to the contact with the photoconductor, so that the durability is high. Rich in Furthermore, even if abrasion or the like occurs in the support (conductive member), the internal fibrous member protrudes from the surface, thereby maintaining the initial characteristics, and enabling stable charging.

In the contact type charger according to the eighth and tenth aspects, since the fibrous member is a carbon nanotube, in addition to the effects of the contact type charger according to the first, second, fourth and sixth aspects, It is possible to provide a contact-type charger that has sufficient resistance to environmental fluctuations such as humidity and has a small fluctuation in charging voltage during long-term use. In the contact type charger utilizing corona discharge in a minute gap between the photosensitive member, contact type charging device, it can reduce the occurrence of ozone and NO _X, and the contact type charging which can realize low voltage of the external power supply Vessels can be provided. This will be described below.

In the contact-type charger according to the eighth and tenth aspects, the conductive ultrafine carbon nanotube having a high aspect ratio is brought into contact with the photosensitive member. When charging the photoreceptor by charge injection, the carbon nanotubes are extremely fine and have a high aspect ratio, so they can be densely arranged on the contact surface with the photosensitive layer, and since the carbon nanotubes have large elasticity, It can bend when it comes into contact with the photosensitive layer, and can contact the photosensitive layer not only at the tip of the carbon nanotube but also on the side surface, and can substantially increase the contact area between the contact-type charger and the photosensitive layer, and inject charge. Speed can be improved. As a result, a sufficient charging voltage can be applied to the photoconductor.

On the other hand, when the photosensitive member is charged by corona discharge in a minute gap between the photosensitive layer and the contact-type charger, the unevenness at the tip of the carbon nanotube is caused because the carbon nanotube has an extremely fine needle shape. The electric field becomes stronger, and the firing voltage can be reduced. Therefore, the voltage to be applied can be reduced as compared with the conventional roller charging, and the corona discharge space can be reduced. As a result, it is possible to reduce the amount of ozone and NO _X generated in the discharge space.

Further, since the carbon nanotube has a high tensile strength in the axial direction, it is very unlikely to be broken when it comes into contact with the photosensitive layer even if it is extremely fine, and it is uniformly dispersed and even inside the support (the inside of the conductive member). It is held and fixed, has improved resistance to destruction and dropout due to local force due to the incorporation of toner particles and paper dust, etc. The life of the vessel can be extended. In addition, even if the support is worn or the like, the internal carbon nanotubes protrude to the surface, the initial characteristics can be maintained, and stable charging can be performed.

In the ninth aspect of the present invention, the single-walled carbon nanotube which satisfies the expressions (1) and (2) at the same time is used as the carbon nanotube. Therefore, the single-walled nanotube has metallic conductivity, and can reduce the contact resistance between the contact-type charger and the photosensitive layer. As a result, more efficient charge injection becomes possible.

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

The contact type charger of the second aspect of the present invention is a charging brush in which carbon nanotubes are held and connected to conductive fibers. Since the carbon nanotube has an extremely small diameter, it can be densely arranged on the conductive fiber in the axial direction. In addition, since the carbon nanotube has great elasticity, it can bend when it comes into contact with the photosensitive layer, and can contact the photosensitive layer not only at the tip of the carbon nanotube but also at the side surface. Therefore, the contact area between the photosensitive layer and the charging brush can be significantly increased as compared with a conventional charging brush in which conductive fibers are made of etching fibers and split fibers. As a result, the charge injection speed can be improved. In addition, even if the support (the conductive fiber) is worn or the like, the internal carbon nanotubes protrude to the surface and the initial characteristics can be maintained, and stable charging can be performed.

The contact-type charger of the fourth aspect is preferably of the eighth aspect.
In the charging roller described in (1), a conductive contact between the charging roller and the photosensitive layer is formed of carbon nanotubes. Carbon nanotubes are chemically stable because they have no dangling bonds, and have very high mechanical strength due to their seamless structure. As a result, the stability of the conductive contacts is very good, and compared to the conventional conductive rubber or water-absorbing sponge roller with conductivity, there is less fluctuation due to the environment and stable charging performance over a long period of time. Can be maintained. In addition, since the carbon nanotube has a very small diameter, it can be densely arranged on the conductive rubber.
Furthermore, since the carbon nanotube has a large elasticity, it can bend when it comes into contact with the photosensitive layer, and can contact the photosensitive layer not only at the tip of the carbon nanotube but also at the side surface. Therefore, although not as remarkable as when a charging brush is used, the conductive contact with the photosensitive layer can be increased, and the charge injection speed can be improved. Also,
Even if abrasion of the support (conductive rubber) or the like occurs, the internal carbon nanotubes protrude from the surface and the initial characteristics can be maintained, and stable charging can be performed.

In the contact-type charger of claim 6, claim 8
Is a charging blade in which carbon nanotubes mainly come into contact with a photosensitive layer. Since carbon nanotubes have a function as a solid lubricant, compared to conventional charged blades without carbon nanotubes,
The friction coefficient between the charging blade and the photosensitive layer can be reduced, and in long-term use, "shaving the photosensitive layer, especially the organic photosensitive layer",
It is difficult to cause mechanical damage such as "wearing the photosensitive layer, especially the organic photosensitive layer", and the life of the photosensitive layer, especially the organic photosensitive layer can be improved. In addition, since the carbon nanotube has great elasticity, it can bend when it comes into contact with the photosensitive layer, and can contact the photosensitive layer not only at the tip but also at the side surface of the carbon nanotube. Therefore, although not so remarkable as when used for a charging brush, the conductive contact with the photosensitive layer can be increased, and the charge injection speed can be improved. In addition, even if abrasion of the support (conductive rubber) or the like occurs, the internal carbon nanotubes protrude from the surface, the initial characteristics can be maintained, and stable charging can be performed.

In the method for manufacturing a contact-type charger according to the eleventh aspect, the support (conductive member) in which the carbon nanotubes are dispersed is mechanically polished using fine particles of alumina or the like, and the carbon nanotubes are used as the support. Protrude from the surface. Therefore, the contact-type charger according to claims 8 to 10 can be manufactured at low cost.

The image recording apparatus according to the twelfth aspect is equipped with the contact type charger according to the first to tenth aspects. For this reason, the above-mentioned effect by these contact type chargers can be obtained.
That is, in either case of charging the photoconductor by charge injection or charging by corona discharge in the minute gap between the photoconductor and the contact type charger, a sufficient charging voltage can be applied to the photosensitive layer, and the , A good image is obtained. In particular, an image recording apparatus equipped with a charging brush and a magnetic brush can provide an image with excellent gradation.
In addition, when the photosensitive member is charged by charge injection, ozone or NO _X is not generated during the charging process, furthermore, if the photosensitive member is charged by corona discharge in a minute gap, it is possible to reduce the corona discharge space, and it can reduce the amount of ozone and NO _X generated in the discharge space. Further, since the charging efficiency is improved by both the charge injection and the corona discharge in the minute gap, the external power supply for charging mounted on the image recording apparatus can be reduced in voltage. Further, the long-term reliability of the contact type charger is improved, and the life of the photoconductor, especially the OPC, is extended, so that the frequency of replacement of the contact type charger and the photoconductor, 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 shows an example (charging brush) of a contact-type charger of the present invention, wherein (a) is a schematic cross-sectional view of the whole;
(B) is a schematic longitudinal sectional view of the charging brush main body.

FIG. 2 is a schematic diagram of a six-membered ring in which a single-walled carbon nanotube is cut open.

3A is an explanatory view of a method of manufacturing the contact-type charger of FIG. 1, and FIG. 3B is a schematic longitudinal sectional view of a charging brush main body.

FIG. 4 is a schematic longitudinal sectional view showing another example of the charging brush main body.

FIG. 5 is a schematic vertical sectional view showing still another example of the charging brush main body.

FIG. 6 shows another example of the contact type charger of the present invention (charging roller).
FIG.

7A and 7B show another example of the charging roller, in which FIG. 7A is a schematic cross-sectional view of the whole, and FIG. 7B is an enlarged view of a part thereof.

FIG. 8 shows still another example (charging blade) of the contact-type charger of the present invention, wherein (a) is a schematic front sectional view,
(B) is a schematic side sectional view.

FIG. 9 is a schematic side sectional view showing another example of the charging blade.

FIG. 10 shows still another example of the charging blade.
(A) is a schematic front sectional view, (b) is a schematic side sectional view.

FIG. 11 shows a conventional contact type charger (conductive rubber roller).
FIG.

FIG. 12 is a schematic cross-sectional view of a conventional contact-type charger (charging brush).

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 OPC (organic photoreceptor) 101 Al substrate 102 organic photosensitive layer 103 DC power supply 110 Contact type charger (charging brush) 111 Metal core 120 Carbon nanotube 122 Carbon black 123 Conductive fiber 123a Conductive fiber (core) 123b Conductive fiber (Sheath) 124 Charging brush main body (rubbing charging member) 500 OPC 501 Al substrate 502 Organic photosensitive layer 503 DC power supply 510 Charging roller 511 Metal core 520 Carbon nanotube 523 Conductive rubber 523a Conductive rubber (inner layer) 523b Conductive rubber ( Outer layer) 524 Charging roller main body (rubbing charging member) 600 OPC 601 Al substrate 602 Organic photosensitive layer 603 DC power supply 610 Charging blade 611 Metal plate 620 Carbon nanotube 623 Conductive rubber 623a Conductive rubber (Inner layer) 623b Conductive rubber (outer layer) 624 Charging blade main body (sliding charging member) 1100 OPC 1101 Al base 1102 Organic photosensitive layer 1103 DC power supply 1110 Conductive rubber roller (charging roller) 1111 Core bar 1124 Conductive rubber (sliding) 2100 OPC 2101 Al substrate 2102 Organic photosensitive layer 2103 DC power supply 2110 Charging brush 2111 Core 2124 Conductive brush (rubbing charging member)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukie Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Hiroyoshi Shoko 1-3-6 Nakamagome, Ota-ku, Tokyo Stock F-term in Ricoh Company (reference) 2H003 BB11 CC05 CC06 3J103 AA02 AA72 EA03 FA12 FA15 FA30 GA02 GA52 HA03 HA12 HA19 HA20 HA52

Claims (12)

[Claims] A rubbing charging member for applying a potential difference between the photoreceptor and the rubbing charging member while bringing the rubbing charging member into rubbing contact with the surface of the photoreceptor; In the contact-type charging device provided, the rubbing charging member includes a conductive member and a fibrous member having conductivity, and the fibrous member having conductivity is formed on at least a part of the conductive member. A contact-type charger having one end held inside the conductive member and the other end protruding outside from the surface of the conductive member. 2. The contact type charger includes a metal core, and a plurality of conductive fibers as conductive members provided on the surface of the metal core and a rubbing and charging member made of the fibrous member. 2. A charging brush, wherein one end of the fibrous member is held inside the conductive fiber, and the other end protrudes outside from the surface of the conductive fiber.
The contact-type charger according to the above. 3. The contact-type charger according to claim 2, wherein the conductive fiber has a multilayer structure, and the fibrous member is held only by the outermost layer. 4. The contact-type charger is a charging roller including a metal core and a rubbing charging member that covers a surface of the metal core, and the rubbing charging member is a conductive rubber as the conductive member. 2. The contact-type charger according to claim 1, comprising: and the fibrous member held by the conductive rubber. 5. The contact-type charger according to claim 4, wherein the conductive rubber has a multilayer structure, and the fibrous member is held only by the outermost layer. 6. The contact-type charger is a charging blade comprising a metal plate and a blade-like rubbing-charging member attached to one end of the metal plate, wherein the rubbing-charging member serves as the conductive member. The contact-type charger according to claim 1, comprising: the blade-shaped conductive rubber; and the fibrous member held by the conductive rubber. 7. The contact-type charger according to claim 6, wherein the conductive rubber has a multilayer structure, and the fibrous member is held only by the outermost layer. 8. The contact-type charger according to claim 1, wherein the fibrous member is a carbon nanotube. 9. The contact-type charger according to claim 8, wherein the carbon nanotube is a single-walled carbon nanotube represented by a chiral vector (Ch) in the following formulas (1) and (2). (Equation 1) (Where a1 and a2 indicate basic translation vectors of a two-dimensional hexagonal lattice, and n, m and k indicate integers.) 10. The contact-type charger according to claim 8, wherein the carbon nanotube is a multi-walled carbon nanotube. 11. The method for manufacturing a contact-type charger according to claim 8, wherein the carbon nanotubes are dispersed in a conductive member that is to hold the carbon nanotubes, and then the carbon nanotubes are dispersed. A method for manufacturing a contact-type charger, comprising a step of mechanically polishing a surface of a member to project the carbon nanotubes from the surface of the conductive member to the outside. 12. An image recording apparatus comprising the contact-type charger according to claim 1.