JP2001166569A - Image forming device and method for manufacturing electrostatic charging device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device having an electrostatic charging member which has high durability over a long period of time and makes it possible to always stably obtain a desired electrostatic charging state and a method capable of surely manufacturing such electrostatic charging member. SOLUTION: The image forming device has an org. photoreceptor or amorphous silicon photoreceptor with which an electrostatic charge image is formed, the electrostatic charging member for electrostatically charging the photoreceptor, a developing device for developing the electrostatic charge image on the photoreceptor, a transfer section for transferring the toner image to a transfer material and a fixing device for fixing the toner image on the transfer material. The electrostatic charging member has a planar grid obtained by forming a gold plating layer on a grid base material made of a stainless steel in a porous planar form. The gold plating layer is preferably formed directly on the surface of the grid base material. In the method for manufacturing the electrostatic charging member, the planar grid is manufactured by forming the gold plating layer on the surface of the grid base material made of the stainless steel by an electroplating method by pulse current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for developing a toner image by visualizing an electrostatic charge image formed on the surface of a photoreceptor by, for example, an electrophotographic method, and transferring the toner image onto a transfer material. The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., configured to form a visible image according to the present invention, and a method of manufacturing a charging device used in such an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic method, a charge is applied to the surface of a photoreceptor to uniformly charge the surface of the photoreceptor, and the surface of the photoreceptor is subjected to image exposure, thereby causing an electrostatic charge on the photoreceptor. It is configured to form an image, and a charging device is used to charge the surface of the photoconductor. This charging device usually controls the amount of charge provided by the charging wire by applying a charging wire (discharge wire) for performing corona discharge and a grid voltage of an appropriate potential to charge the surface of the photoreceptor. It is composed of a grid electrode (hereinafter, simply referred to as a “grid”) for controlling a potential, and a support member that supports the charging wire and the grid. As the grid of the charging device, a wire grid and a perforated plate-like grid in which a large number of through holes are formed in a metal plate made of stainless steel or the like (for example, an etching in which a large number of through holes are formed by etching). Grid).

However, when a wire grid is used, the charging operation characteristics fluctuate due to the attachment of contaminants such as toner particles used for visualizing an electrostatic charge image. The potential is likely to fluctuate.
On the other hand, the plate-like grid has a relatively large area, and the fluctuation of the charging potential of the photoconductor due to contamination is small even during long-term use, and therefore, the stability of the charging potential obtained on the photoconductor is excellent. This is basically preferable because it has high durability.

However, since the plate-shaped grid is usually made of an iron-based metal such as stainless steel, it is oxidized by moisture in a high-humidity environment or ozone generated by corona discharge during charging operation. Therefore, in a charging device having a plate-like grid, a high durability cannot be obtained for a long period of time, and the charging operation characteristics are changed. There is a problem that the potential fluctuates, and the desired charged potential cannot be always stably obtained.

Conventionally, in order to cope with such a problem, Japanese Patent Application Laid-Open No. H11-40316 discloses a plate-like grid made by coating a grid substrate made of stainless steel with nickel and further forming a gold coating. Attempts to ameliorate the problem of corrosiveness have been proposed. However, this method has a problem that the gold coating is easily peeled off as described in the publication.

In order to investigate this problem, the present inventors,
According to the description of the publication, a stainless steel grid substrate was coated with nickel, and further, a plate-like grid obtained by performing gold coating thereon was examined in detail for the phenomenon of peeling of the gold coating. However, it was found that the peeling of the gold coating occurred at the interface between the stainless steel forming the grid base material and the nickel coating. This is thought to be due to the fact that if a pinhole or the like is formed in the gold coating, the nickel coating is exposed and corroded, and further the corrosion of the nickel coating progressed, resulting in peeling of the gold coating. Can be As described above, the means disclosed in the above publication discloses that the nickel layer is interposed in order to improve the adhesion of the gold coating, but on the other hand, the gold coating is easily peeled off. The problem is inherent. It should be noted that JP-A-61-
No. 88283 describes using a grid made of gold-plated tungsten wire.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in the plate grid of the charging device, and an object thereof is to provide a high durability for a long period of time. It is another object of the present invention to provide an image forming apparatus including a charging device that has stable charging operation characteristics and always stably obtains a desired charging state on a photosensitive member. Another object of the present invention is to provide a charging device for an image forming apparatus, which has high durability over a long period of time, has a stable charging operation characteristic, and can always obtain a desired charging state on a photoconductor. An object of the present invention is to provide a method that can be reliably manufactured.

[0008]

An image forming apparatus according to the present invention comprises an organic photosensitive member on which an electrostatic image is formed, a charging device for charging the organic photosensitive member, and an organic photosensitive member formed on the organic photosensitive member. A developing unit that visualizes the electrostatic image formed to form a toner image, a transfer unit that transfers the toner image to a transfer material,
A fixing device for fixing the toner image transferred to the transfer material, wherein the charging device is a plate-like grid formed by forming a gold plating layer on a perforated plate-like stainless steel grid base material. Is provided.

In this image forming apparatus, the gold plating layer can be formed directly on the surface of a perforated plate-shaped stainless steel grid substrate. Further, the organic photoreceptor preferably has a surface layer containing a siloxane-based resin having a crosslinked structure.

Further, the image forming apparatus of the present invention comprises an amorphous silicon-based photosensitive member on which an electrostatic charge image is formed, a charging device for charging the amorphous silicon-based photosensitive member, A developing unit that visualizes the electrostatic charge image formed on the silicon-based photoconductor to form a toner image, a transfer unit that transfers the toner image to a transfer material, and fixes the toner image transferred to the transfer material An image forming apparatus comprising a fixing device, wherein the charging device is provided with a plate-shaped grid formed by directly forming a gold plating layer on a surface of a perforated plate-shaped stainless steel grid base material. Features.

In the above, the thickness of the gold plating layer is 0.3
It is preferably at least μm.

The image forming apparatus is provided with surface potential detecting means for detecting the surface potential of the photosensitive member, and a charging current supplied to the charging device based on information detected by the surface potential detecting means. Further, it is preferable that a control means for controlling a grid voltage applied to the plate grid is provided.

According to the method of the present invention, there is provided a method for manufacturing a charging device provided with a plate-like grid used in an image forming apparatus, comprising the steps of: It is characterized in that a plate-shaped grid is manufactured by forming a gold plating layer by a method.

In this method, the thickness of the formed gold plating layer is preferably set to 0.3 μm or more.

The image forming apparatus of the present invention has a charging device provided with a plate-shaped grid. The plate-shaped grid of the charging device is provided on a perforated plate-shaped stainless steel grid substrate by electrolysis using a pulse current. It is characterized in that a gold plating layer is formed by a plating method.

[0016]

According to the present invention, in an image forming apparatus having an organic photoreceptor, a charging device for charging the organic photoreceptor has a plate-like grid, and the plate-like grid is made of a perforated plate made of stainless steel. By forming the gold plating layer on the grid base material, in particular, by the gold plating layer being formed directly on the surface of the grid base material, the plate-shaped grid can be used for a long time. Since the gold plating layer does not peel off and has high durability, the charging device operating characteristics of the charging device become stable, and therefore, in the process of forming an electrostatic charge image on the organic photoconductor, the organic photoconductor is always used. It can be stably charged to an intended charging state. Such a charging device is particularly preferable when the surface layer of the organic photoreceptor contains a siloxane-based resin having a crosslinked structure.

Further, in the image forming apparatus of the present invention, when the photosensitive member is an amorphous silicon-based photosensitive member, the plate-like grid of the charging device has a gold plating layer formed directly on the surface of the grid base material. With this structure, the gold-plated layer does not peel off even when used for a long period of time, and has high durability. Therefore, the amorphous silicon-based photoconductor is always stably charged as intended. It can be charged to a state.

In the above, when the thickness of the gold plating layer in the plate grid is 0.3 μm or more, the intended operation and effect can be reliably obtained.

In the image forming apparatus, a surface potential detecting means for detecting a surface potential of the photosensitive member is provided, and a charging current supplied to the charging device and a grid voltage applied to the plate grid are provided based on information from the surface potential detecting means. By controlling the above, the features of the above-described charging device can be sufficiently exhibited.

According to the method of manufacturing the charging device of the present invention, the gold plating layer of the plate grid is formed by the electroplating method using a pulsed current, so that the electroplating method using a direct current can be used. The formed gold plating layer has a dense and hard structure with few pinholes, and is uniform even if the layer thickness is thin, and has high adhesion to the stainless steel surface forming the grid base material. It becomes what has.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. 1 and 2 schematically show an example of the configuration of a charging device used in the image forming apparatus of the present invention. FIG. 1 is a perspective view, and FIG. 2 is an exploded perspective view thereof. In these figures, 1 is a plate-like grid for controlling the charging potential of the photoreceptor by applying a voltage, 2 is a charging wire for performing corona discharge, 3 is a spring for extending the grid, 4
Denotes a support member that supports the charging wire 2 and the plate-shaped grid 1, and these constitute a charging device 10. The charging device 10 may be, for example, a scorotron type or a corotron type in which a DC negative corona discharge is performed.

The charging wire 2 has a wire diameter of, for example, 0.1 mm.
06mm tungsten wire gold plated,
Since it has high durability, it can be preferably used. The plate-shaped grid 1 is formed by forming a large number of through holes in a sheet metal made of stainless steel or the like by etching or the like, and performing metal plating on the surface of the resulting porous plate-shaped grid base material. The metal plating includes nickel plating and gold plating. In the present invention, gold plating is particularly required. The plate grid formed in this manner is also called an etching grid.

(Embodiment-1) This embodiment-1
Describes an aspect relating to a method of manufacturing a charging device for an image forming apparatus of the present invention. According to the present invention, a grid substrate made of a perforated plate-shaped stainless steel is subjected to plating, and gold plating is performed by an electrolytic plating method using a pulse current by applying a pulse voltage to directly apply the surface of the grid substrate. Then, a gold plating layer is formed, and a charging device used in an image forming apparatus is configured using the plate-like grid obtained thereby.

The thickness of the formed gold plating layer is 0.3 μm
It is preferable that it is above. If this thickness is less than 0.3 μm, pinholes are likely to occur and become non-uniform,
When the stainless steel of the grid substrate is corroded through the pinhole, the charged potential obtained on the photoconductor is likely to be partially unstable. Conventionally, the gold plating layer was considered to be easily peeled, but the present inventors have examined this peeling in detail, and in particular, by applying a specific plating method, the grid of the gold plating layer formed It has been found that the adhesion to a substrate can be dramatically improved.

The electroplating method using a pulse current for forming a gold plating layer is not particularly limited in its process and conditions, and can be performed in the same manner as a normal method. The gold plating bath is roughly classified into a high-temperature or low-temperature cyan alkali bath, a neutral bath, a weak alkali bath, an acidic bath, and the like, but a bath in which a dense and hard gold plating layer is formed is preferable. In order to make the gold plating layer hard, for example, cobalt or nickel can be added to an acidic bath. The material of the anode serving as the counter electrode is not particularly limited, and for example, a material made of nickel chrome steel, carbon, or the like can be used. As an example of the composition of the gold plating solution constituting the gold plating bath, 3.8 g of potassium cyanide and 7.5 carbonate of potassium per liter were used.
g and 3.8 g of bluish potassium. The temperature of the bath is, for example, 49-71 ° C.

The current in the electrolytic plating method is not particularly limited as long as it is a pulse current. Specifically, for example, various pulse currents obtained by rectifying alternating current of a commercial power supply can be used, and a pulse current of a rectangular wave is preferably used. The pulse width (on time) of this pulse current can be set, for example, in the range of several microseconds to several hundred microseconds. The on time is preferably longer than the off time or the charging time. Thereby, the formed gold plating layer can have a fine structure. The pulse current has a current density of, for example, 0.5 to 1.6 A / dm ² , and a voltage of, for example, 2 to 6 A / dm ² .
V.

In the process of actually performing gold plating, various pre-processing steps and post-processing steps are performed on the object to be plated. In one example, for example, chemical polishing, water washing, acid immersion, water washing, pure water immersion, gold plating, water washing, and drying are performed.

According to the electrolytic plating method using a pulse current as described above, especially when a gold plating layer is formed directly on the surface of a grid base material made of stainless steel, the formed gold plating layer is dramatically improved. It was confirmed that the adhesiveness was improved. Further, according to the method of forming a gold plating layer using the above-described electrolytic plating method using a pulse current, the same applies to the case of forming a gold plating layer on a nickel plating layer formed on the surface of a grid base material. The effect is obtained.

In the electroplating method using a pulse current, electrolysis with a high current density is performed at the cathode interface as compared with the plating method using a direct current, so that the crystal grain size generated is small, and thus the structure is reduced. A dense, high-density, hard gold-plated layer is formed, and this gold-plated layer has few pinholes, and a uniform gold-plated layer is formed even if the layer thickness is small. Then, since the surface of the stainless steel forming the cathode and the deposited gold can be easily alloyed, for example, the gold plating layer has high adhesion.

(Embodiment 2) This embodiment 2
Describes an embodiment in which an organic photoconductor is used as a photoconductor charged by a charging device in the image forming apparatus of the present invention. In the image forming apparatus of the present invention, an organic photoconductor is used as a photoconductor on which an electrostatic image is formed. Since the surface of an organic photoreceptor is mainly composed of a resin component, the surface of the photoreceptor deteriorates due to the chemical action of ozone generated by corona discharge by a charging device. In a device having a cleaning blade in the part, since the surface is worn by the rubbing action of the cleaning blade, the deteriorated surface portion is gradually but surely removed, and as a result, the surface by the ozone or the like is thereby removed. The problem of degradation is effectively eliminated,
The charging potential by the charging operation can be stably maintained over a long period of time.

The organic photoreceptor used in the present invention preferably has a surface layer containing a siloxane-based resin having a crosslinked structure. Since the surface layer contains a siloxane-based resin having a crosslinked structure, the surface of the organic photoreceptor is hardened to have a small friction coefficient, and damage due to abrasion of the organic photoreceptor surface due to contact with a cleaning blade occurs. Can be remarkably improved and abrasion can be suppressed. As a result, the charging potential can be further stabilized, and the durability of the organic photoreceptor can be significantly improved.

The organic photoreceptor preferably used in the present invention is, for example, a charge transport layer as a surface layer containing a siloxane-based resin having an undercoat layer, a charge generation layer and a crosslinked structure on a surface of a drum-shaped substrate. Are laminated in this order. Further, the charge transport layer is a lower layer containing a charge transport material and a binder resin,
It is preferable that the upper layer contains a charge transport material and a siloxane-based resin having a cross-linked structure, and in this case, the upper layer is a surface layer.

It is preferable that the siloxane-based resin having a crosslinked structure has a structural unit having a charge transporting property. A siloxane-based resin having a structural unit having charge transport performance and having a crosslinked structure can be produced by a known method using an organosilicon compound having a hydroxyl group or a hydrolyzable group. Such an organosilicon compound is specifically represented by the following general formulas (A) to (D).

[0034]

Embedded image In the general formulas (A) to (D), R ^{1 to} R ⁶ represent an organic group in which a carbon atom is directly bonded to a silicon atom in the formula, and Z ^{1 to} Z ⁴ represent a hydroxyl group or a hydrolyzable group. Represents
In this case, R ² and R in the general formula (C)
³ and R ⁴ , R ⁵ and R in the general formula (D)
⁶ may be the same or different from each other.

Z ¹ in the above general formulas (A) to (D)
When -Z ⁴ is a hydrolyzable group, the hydrolyzable group includes a methoxy group, an ethoxy group, a methylethylketoxime group, a diethylamino group, an acetoxy group, a propenoxy group, a propoxy group, a butoxy group, a methoxyethoxy group and the like. No.

Examples of the organic group represented by R ^{1 to} R ⁶ in which a carbon atom is directly bonded to a silicon atom include alkyl groups such as methyl group, ethyl group, propyl group and butyl group.
Aryl groups such as phenyl group, tolyl group, naphthyl group and biphenyl group, γ-glycidoxypropyl group, β- (3,
Epoxy-containing groups such as 4-epoxycyclohexyl) ethyl group, (meth) acryloyl groups such as γ-acryloxypropyl group and γ-methacryloxypropyl group, γ-hydroxypropyl group, and 2,3-dihydroxypropyloxypropyl A hydroxyl group such as a vinyl group, a vinyl group such as a vinyl group and a propenyl group, a mercapto group such as a γ-mercaptopropyl group, a γ-aminopropyl group, an N-β- (aminoethyl) -γ-aminopropyl group and the like. Amino-containing group, γ-chloropropyl group, 1,1,1-trifluoropropyl group,
Examples include a halogen-containing group such as a nonafluorohexyl group and a perfluorooctylethyl group, and other nitro groups and cyano-substituted alkyl groups.

In general, the organosilicon compound used as a raw material of the siloxane-based resin is one in which the number n of hydrolyzable groups bonded to a silicon atom is 1, and the polymerization reaction of the organosilicon compound is not effective. It will be suppressed. When n is 2, 3, or 4, a polymerization reaction easily occurs. Particularly, when the organic silicon compound is 3 or 4, a crosslinking reaction can be advanced to a high degree. Therefore, by controlling the abundance ratio of each component having a different number n of hydrolyzable groups in the organosilicon compound raw material subjected to the polymerization reaction, the storage stability of the obtained coating layer liquid, the hardness of the coating layer, etc. Can be controlled.

As a raw material of the siloxane-based resin, a hydrolyzed condensate obtained by hydrolyzing the organosilicon compound under acidic or basic conditions to oligomerize or polymerize can also be used. As described above, the siloxane-based resin is obtained by reacting a monomer, oligomer or polymer having a siloxane bond in a chemical structural unit in advance as described above (this reaction includes a hydrolysis reaction, a reaction using a system to which a catalyst or a crosslinking agent is added, and the like). This means a resin that has formed and cured a three-dimensional network structure. That is, it means a siloxane-based resin having a cross-linked structure formed by promoting a siloxane bond by a hydrolysis reaction and subsequent dehydration condensation of an organosilicon compound having a siloxane bond to form a three-dimensional network structure.

Further, the siloxane-based resin may be a resin in which colloidal silica having a hydroxyl group or a hydrolyzable group is contained to incorporate the silica particles into a part of a crosslinked structure.

In the present invention, “a siloxane-based resin having a structural unit having a charge transporting property and having a cross-linking structure” is defined as a chemical structure having the characteristic of exhibiting electron or hole drift mobility (this is referred to as a “charged material”). "A structural unit having transport performance") is incorporated into a siloxane-based resin as a partial structure. Specifically, a siloxane-based resin having a structural unit having charge transporting performance and having a crosslinked structure is a compound generally used as a charge transporting substance (hereinafter referred to as a “charge transporting compound” or “CTM”). ") As a partial structure in the siloxane-based resin.

The above-mentioned structural unit having charge transport performance is a structural unit exhibiting the property of having electron or hole drift mobility, or a charge transporting compound residue. Another definition is Time. -Of-Flight
It can also be expressed as a structural unit from which a detection current due to charge transport can be obtained by a known method capable of detecting charge transport performance such as the t method, or a charge transporting compound residue.

Hereinafter, a charge transporting compound capable of forming a structural unit having charge transporting ability by reacting with an organosilicon compound in a siloxane-based resin will be described. For example, as the hole transport type CTM, for example, oxazole, oxadiazole, thiazole, triazole,
Imidazole, imidazolone, imidazoline, bisimidazolidin, styryl, hydrazone, benzidine, pyrazoline, stilbene compound, amine, oxazolone, benzothiazole, benzimidazole, quinazoline, benzofuran, acridine, phenazine, aminostilbene, poly-N-vinylcarbazole, poly Examples thereof include those containing a chemical structure such as -1-vinylpyrene and poly-9-vinylanthracene as a partial structure of the siloxane-based resin.

The electron transport type CTM includes, for example, succinic anhydride, maleic anhydride, phthalic anhydride, pyromellitic anhydride, melitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, nitrobenzene, dinitrobenzene, and trinitrobenzene. Nitrobenzene, tetranitrobenzene, nitrobenzonitrile, picryl chloride, quinone chlorimide, chloranil, bromanyl, benzoquinone, naphthoquinone, diphenoquinone, tropoquinone,
Anthraquinone, 1-chloroanthraquinone, dinitroanthraquinone, 4-nitrobenzophenone, 4,4 '
-Dinitrobenzophenone, 4-nitrobenzalmalone dinitrile, α-cyano-β- (p-cyanophenyl)
-2- (p-chlorophenyl) ethylene, 2,7-dinitrofluorene, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 9-
Fluorenylidenedicyanomethylenemalononitrile, polynitro-9-fluoronylidenedicyanomethylenemalonodinitrile, picric acid, o-nitrobenzoic acid, p-
Those containing a chemical structure such as nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, and melitic acid as a partial structure of the siloxane-based resin. Can be mentioned.

In the present invention, the structural unit having a preferable charge transporting property is a residue of a commonly used charge transporting compound as described above, and is represented by a carbon atom or a silicon atom constituting the charge transporting compound. It binds to a linking atom or a linking group represented by Y in the following general formula (1), and is contained in the siloxane-based resin via Y.

[0045]

Embedded image

In the general formula (1), X is a structural unit having a charge transporting property, and a group bonding to Y in the formula via a carbon atom or a silicon atom constituting the imparting group;
Is a divalent or higher valent atom or group excluding adjacent bonding atoms (Si and C). However, when Y is a trivalent or higher valent atom, the bond of Y other than Si and C in the formula is bonded to any constituent atom in the curable resin capable of bonding,
Alternatively, it has a structure (group) linked to another atom or molecular group.

In the general formula (1), when Y is an atom, the atom is particularly an oxygen atom (O),
A sulfur atom (S) and a nitrogen atom (N) are preferred. here,
When Y is a nitrogen atom (N), the linking group is represented by -NR-. (R is a hydrogen atom or a monovalent organic group.)

In the general formula (1), the structural unit X having charge transport performance is shown as a monovalent group.
When the charge-transporting compound to be reacted with the siloxane-based resin has two or more reactive functional groups, the charge-transporting compound may be bonded as a divalent or higher-valent crosslink group in the curable resin, or simply as a pendant group. They may be joined. The atom,
That is, the atoms of O, S, and N are formed by the reaction of a hydroxyl group, a mercapto group, or an amine group and an organosilicon compound having a hydroxyl group or a hydrolyzable group, respectively, introduced into a compound having a charge transporting ability. It is a linking group that incorporates a structural unit having charge transport performance into a resin as a partial structure.

Next, a hydroxyl group, a mercapto group, an amine group,
The charge transporting compound having an organic silicon-containing group will be described. The charge transporting compound having a hydroxyl group is a charge transporting substance having a commonly used structure and a compound having a hydroxyl group. That is, a charge-transporting compound represented by the following general formula (2), which can form a resin layer by bonding to a curable organosilicon compound, can be exemplified, but is limited to the following structure. Not a thing,
Any compound having a charge transporting ability and having a hydroxyl group may be used.

[0050]

## STR3 ## Formula ^{(2) X- (R 7 -OH} ) m wherein, X: structural unit R ⁷ having charge transport performance: a single bond, a substituted or unsubstituted alkylene group, an arylene group m:. 1 to It is an integer of 5.

Among these, representatives are as follows. For example, a triarylamine-based compound has a triarylamine structure such as triphenylamine as a structural unit having charge-transporting performance (ie, X), and has a carbon atom constituting X or X
Compounds having a hydroxyl group via an alkylene or arylene group extended from are preferably used.

1. Triarylamine compounds

Embedded image

2. Hydrazine compounds

Embedded image

3. Stilbene compounds

Embedded image

4. Benzidine compound

Embedded image

5. Butadiene compound

Embedded image

Next, specific examples of the charge transporting compound having a mercapto group are shown below. The charge transporting compound having a mercapto group is a charge transporting substance having a commonly used structure and a compound having a mercapto group.
That is, a resin layer can be typically formed by bonding with a curable organosilicon compound.
There can be mentioned a charge transporting compound represented by
The compound is not limited to this structure, and may be any compound having a charge transporting ability and a mercapto group.

[0058]

Embedded image Formula ^{(3) X- (R 8 -SH} ) m wherein, X: structural units R ⁸ having a charge transporting performance: a single bond, a substituted or unsubstituted alkylene, arylene group m: 1 to 5 Is an integer.

Among these, representatives are as follows.

Embedded image

Further, the charge transporting compound having an amino group will be described. The charge transporting compound having an amino group is a charge transporting substance having a commonly used structure and a compound having an amino group. That is, a charge-transporting compound represented by the following general formula (4), which can typically form a resin layer by bonding to a curable organosilicon compound, can be mentioned, but is limited to this structure. Instead, any compound having charge transporting ability and having an amino group may be used.

[0061]

X- (R ⁹ -NR ¹⁰ H) m wherein X: Structural unit having charge transport performance R ⁹ : Single bond, substituted, unsubstituted alkylene, substituted, unsubstituted Arylene group R ¹⁰ : hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group m: an integer of 1 to 5.

[0062] Of these, representative ones are as follows.

Embedded image

Among the charge transporting compounds having an amino group, in the case of a primary amine compound (—NH ₂ ), two hydrogen atoms may react with an organosilicon compound and be linked to a siloxane structure. In the case of a secondary amine compound (—NHR ¹⁰ ), one hydrogen atom reacts with the organosilicon compound, and R
¹⁰ may be a group remaining as a branch, a group causing a crosslinking reaction, or a compound residue containing a charge transport substance.

Further, the charge transporting compound having a silicon atom-containing group will be described. The charge transporting compound having a silicon atom-containing group is a charge transporting substance having a structure represented by the following general formula (5). This compound can also combine with the curable organosilicon compound to form a resin layer.

[0065]

Embedded image X-(— Y—Si (R ¹¹ ) _3-a (R ¹² ) _a ) n (In the general formula (5), X represents a group containing a structural unit having charge transport performance. R ¹¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group or an aryl group, R ¹² represents a hydrolyzable group or a hydroxyl group, and Y represents a substituted or unsubstituted alkylene group or an arylene group. Represents an integer of 1 to 3, and n represents an integer.)

Among these, representatives are as follows. The raw material for forming the siloxane-based resin is an organosilicon compound containing the structural units represented by the general formulas (A) to (D) as components. As the composition ratio, for example, when the structural unit component represented by the general formula (A) is described as “component (A)”, component (C) + (D) is added to 1 mole of component (A) + (B). Is preferably used in a ratio of 0.05 to 1 mol. When colloidal silica (hereinafter referred to as “component (E)”) is added, the total mass of components (A) + (B) + (C) + (D) is 10%.
It is preferable to use the component (E) in a ratio of 1 to 30 parts by mass relative to 0 part.

The amount of the reactive charge transporting compound capable of forming a resin layer by reacting with the organosilicon compound or colloidal silica (hereinafter referred to as “component (F)”) is determined by the amount of the component ( The amount is preferably 1 to 500 parts by mass with respect to 100 parts by mass of (A) + (B) + (C) + (D). When the ratio of the components (A) and (B) is too small, the obtained siloxane resin has a low crosslinking density and insufficient hardness. On the other hand, when the ratio of the components (A) + (B) is excessive, the obtained siloxane resin has a high crosslinking density and becomes a brittle resin layer even if the hardness is sufficient.

When the proportion of the colloidal silica of the component (E) is not appropriate, the tendency due to excess or deficiency is the same as the case where the component (A) + (B) is excessive or deficient. on the other hand,
When the proportion of the component (F) is low, the charge transporting ability of the obtained siloxane resin becomes small, so that the sensitivity as a photoreceptor is lowered and the residual potential is increased. When it is high, the film strength of the obtained siloxane resin layer tends to be low.

The siloxane-based resin having a structural unit having charge transporting ability and having a crosslinked structure used in the present invention is obtained by adding a catalyst or a crosslinking agent to a monomer, oligomer or polymer having a siloxane bond as a structural unit in advance. In addition, a three-dimensional network structure may be formed by forming a new chemical bond, and a siloxane bond may be promoted by a hydrolysis reaction and a subsequent dehydration condensation to form a tertiary compound from a monomer, oligomer or polymer. An original network structure can be formed. In general, a three-dimensional network structure can be formed by a condensation reaction of a composition having an alkoxysilane or a composition having an alkoxysilane and colloidal silica.

Examples of the catalyst used for forming the three-dimensional network structure include alkali metal salts of organic carboxylic acids, nitrous acid, sulfurous acid, aluminate, carbonic acid and thiocyanic acid, and organic amine salts (water). Tetramethylammonium oxide, tetramethylammonium acetate), tin organic acid salts (stannas octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin malate), aluminum or zinc Octene acid, naphthenate, acetylacetone complex and the like.

The layer structure of the organic photoreceptor is not particularly limited, but may be a charge generation layer, a charge transport layer, or a charge generation / charge transport layer (a single layer having both a charge generation function and a charge transport function). It is preferable that a surface layer is coated on a photosensitive layer such as a layer type photosensitive layer). Further, the charge generation layer, the charge transport layer, or the charge generation /
Each layer of the charge transport layer may be composed of a plurality of layers.

Examples of the charge generation material (CGM) contained in the charge generation layer of the organic photoreceptor include phthalocyanine pigments, polycyclic quinone pigments, azo pigments, perylene pigments, indigo pigments, quinacridone pigments, azurenium pigments, squalilium dyes, Examples include cyanine dyes, pyrylium dyes, thiopyrylium dyes, xanthene dyes, triphenylmethane dyes, styryl dyes, and the like. These charge generating substances (CGM) are used alone or in combination with a suitable binder resin to form a layer. .

Examples of the charge transport material (CTM) contained in the charge transport layer include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives,
Imidazolone derivatives, imidazoline derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds,
Benzidine compound, pyrazoline derivative, stilbene compound, amine derivative, oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-vinylcarbazole, poly-1- Vinylpyrene, poly-9-
Vinyl anthracene and the like are mentioned, and these charge transport materials (CTM) are usually used together with a binder to form a layer.

As the binder resin contained in the charge generation layer (CGL) or the charge transport layer (CTL), polycarbonate resin, polyester resin, polystyrene resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, Polyvinyl butyral resin, polyvinyl acetate resin, styrene-butadiene resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-maleic anhydride copolymer resin, urethane resin, silicone resin, epoxy resin, silicone-
Examples thereof include alkyd resins, phenol resins, polysilane resins, and polyvinyl carbazole.

The ratio of the charge generation material to the binder resin in the charge generation layer is preferably from 1:10 to 10: 1 by mass. Further, the thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm. The charge transport layer can be formed by dissolving the charge transport material and the binder resin in an appropriate solvent, and applying and drying the solution. The mixing ratio of the charge transport material and the binder resin is 10: 1 to 1 by mass.
Preferably it is 1:10. The thickness of the charge transport layer is
Usually, it is preferably 5 to 50 μm, particularly preferably 10 to 40 μm. When a plurality of charge transport layers are provided, the thickness of the upper layer of the charge transport layer is preferably 10 μm or less, and the entire thickness of the charge transport layer provided below the upper layer of the charge transport layer It is preferably smaller than the thickness.

The surface layer containing a siloxane-based resin in the organic photoreceptor preferably used in the present invention may serve also as the charge transport layer when the surface layer is a charge transport layer. Alternatively, it is preferably provided as a surface layer separate from the charge generation layer. In this case, an adhesive layer may be provided between the photosensitive layer and the surface layer. Further, for the purpose of improving the surface characteristics of the electrophotographic photosensitive member, a thinner protective layer may be provided on the surface layer.

Examples of the conductive support for the organic photoreceptor include: (1) a metal plate such as an aluminum plate or a stainless steel plate; or (2) a thin metal layer such as aluminum, palladium, or gold on a support such as paper or a plastic film. (3) A material in which a layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide is provided by coating or vapor deposition on a support such as paper or a plastic film. .

As the material of the conductive support, a metal material such as aluminum, copper, brass, steel, stainless steel or the like, or a plastic material formed into a belt or a drum is used. Among them, aluminum excellent in cost and workability is preferably used,
Usually, a thin-walled cylindrical aluminum tube formed by extrusion or drawing is often used. Further, the conductive support may have a surface on which a sealed alumite film is formed.

As a coating method for producing the above-mentioned organic photoreceptor, coating methods such as dip coating, spray coating, and circular amount control type coating are used. In order to minimize the dissolution of the lower layer film and to achieve a uniform coating process, the coating process is performed by spray coating or coating with a circular amount control type (a typical example is a circular slide hopper type). Preferably, a method is used. The spray coating is described in, for example, JP-A-3-90250 and JP-A-3-26923.
Japanese Patent Application Laid-Open No. 58-189061 describes the details of the circular amount control type coating.

In the production of the organic photoreceptor, after the resin layer is applied and formed, the temperature is 50 ° C. or higher, preferably 60 to 20 ° C.
It is preferable to heat and dry at a temperature of 0 ° C. By this heating and drying, the remaining coating solvent can be reduced, and the curable resin layer can be sufficiently cured.

Next, a specific production example of the organic photoreceptor will be described. 60 g of polyamide resin “Amilan CM-8000” (manufactured by Toray Industries, Inc.) was dissolved and dispersed in 1600 ml of methanol to prepare an intermediate layer composition solution, which was applied by dip coating onto a washed cylindrical aluminum substrate. Then, an intermediate layer having a thickness of 0.3 μm is formed. 60 g of Y-type titanyl phthalocyanine and 700 g of a silicone resin solution “K
R5240 "(15% xylene-butanol solution, Shin-Etsu Chemical Co., Ltd.) was mixed with 2000 ml of 2-butanone,
The mixture was subjected to a dispersion treatment using a sand mill for 10 hours to prepare a charge generation layer coating solution. This charge generation layer coating solution is applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.2 μm. The charge transporting material represented by the following structural formula (D
1) 200 g, 300 g of bisphenol Z-type polycarbonate "Iupilon Z300" (manufactured by Mitsubishi Gas Chemical Company) and 2000 ml of 1,2-dichloroethane were mixed and dissolved to prepare a charge transport layer coating solution. This charge transport coating solution is applied on the charge generation layer by a dip coating method,
A charge transport layer having a thickness of 20 μm is formed.

10 parts by mass of a polysiloxane resin consisting of 80 mol% of methylsiloxane units and 20 mol% of methyl-phenylsiloxane units were added with molecular sieve 4A and left to stand for 15 hours to dehydrate. This resin was dissolved in 10 parts by mass of toluene, and 5 parts by mass of methyltrimethoxysilane and 0.2 parts by mass of dibutyltin acetate were added thereto to form a uniform solution. The dihydroxymethyltriphenylamine (Exemplified Compound T-
1) 6 parts by mass were added and mixed, and this solution was dried to a thickness of 2 μm.
m on the charge transport layer as a surface layer,
The organic photoreceptor can be manufactured by performing the heat curing for 1 hour.

[0083]

Embedded image

In the present invention, in the image forming apparatus, the above-mentioned organic photoreceptor is used as a photoreceptor, and a charging device for charging the photoreceptor when forming an electrostatic charge image on the organic photoreceptor is used. By applying a plate having a gold-plated grid, remarkable stabilization and durability can be obtained over a long period of time. In this case, as the plate-shaped grid of the charging device, a plate-shaped grid formed by forming a gold plating layer on a grid base material made of perforated plate-shaped stainless steel is applied.

In the plate-shaped grid of the charging device, a perforated plate-shaped stainless steel grid base material may be nickel-plated, and gold plating may be performed on the nickel-plated layer to form a gold-plated layer. The gold plating is preferably performed directly on the surface of a stainless steel grid substrate to form a gold plating layer. When the gold plating layer is formed via the nickel plating layer,
For example, when a pinhole is present in the gold plating layer or when a scratch is generated, the exposed nickel has a high ionization tendency as a metal, so that the interface between the grid base made of stainless steel and the nickel plating layer is formed. The nickel effect corrodes easily due to the electrode effect in the above, and eventually, the gold plating layer together with the nickel layer easily peels off from the surface of the grid base material. The thickness of the gold plating layer is preferably 0.3 μm or more, as described above.

Further, as described in the first embodiment, it is preferable to use a plate-like grid on which a gold plating layer is formed by an electrolytic plating method using a pulse current.
The surface layer of the organic photoreceptor preferably contains a siloxane-based resin having a crosslinked structure. That is,
Since the siloxane-based resin having a crosslinked structure is hard,
Since the organic photoreceptor having the surface layer is suppressed from abrasion even if it is rubbed by a cleaning blade, it is possible to suppress a change in charging potential due to a decrease in the thickness of the photosensitive layer.

Further, the charging device as described above is provided with detection means for detecting the surface potential of the organic photoreceptor, as will be described later, and based on information obtained by this detection means, a charging wire in the charging device is connected to the charging device. It is preferable that the present invention is applied to an image forming apparatus provided with control means for controlling the supplied charging current and the grid voltage applied to the plate grid. This makes it possible to change and correct the fluctuation of the charging potential due to deterioration of the surface layer of the photoreceptor due to ozone and a decrease in the film thickness to an appropriate charging potential over a long period of time, thereby further improving the durability of stabilizing the charging potential. I do.

(Embodiment-3) Embodiment-3
Describes an embodiment in which an amorphous silicon-based organic photoconductor is used as a photoconductor charged by a charging device in the image forming apparatus of the present invention. In the image forming apparatus of the present invention, an amorphous silicon photoconductor is used as a photoconductor on which an electrostatic image is formed. As the amorphous silicon-based photoconductor, a known photoconductor can be used. Amorphous silicon photoreceptors are hard and durable, but on the other hand, they have poor charging performance, so a corona discharge with a high charging current is required in the charging device to obtain the desired charging state. As a result, the influence on the grid increases, so that the durability of the charging device is inevitably low.

For example, a conventionally known perforated plate-shaped stainless steel grid base material coated with nickel and further coated with gold has a more effective electrode effect at the interface between stainless steel and nickel. Because of this, the durability of the charging device is significantly impaired.

For this reason, in the present invention, as a charging device for charging the amorphous silicon-based photoreceptor, a gold plating layer is formed by directly performing gold plating on the surface of a grid substrate made of stainless steel. The one having a plate-like grid is applied. According to such a configuration, the durability of the charging device can be improved, and the overall durability of the image forming apparatus can also be improved. The thickness of the gold plating layer in the plate grid of this charging device is preferably 0.3 μm or more. Further, as described in the first embodiment, it is preferable to use a plate-shaped grid plated with gold by an electrolytic plating method using a pulse current.

FIG. 3 is an explanatory diagram showing an example of a main part of the configuration of the image forming apparatus of the present invention.
Digital electrophotography is applied. The configuration of this image forming apparatus is the same as that of Embodiments 1, 2, and 3 described above.
Can be applied to any of the above.

The image forming apparatus shown in FIG. 3 has a drum-shaped photosensitive member 21 on which an electrostatic image is formed, a charging device 22 for charging the photosensitive member 21, and an electrostatic image formed on the photosensitive member 21. A developing unit 23 that forms a toner image by visualizing the image, a transfer unit that has a transfer electrode 24 that transfers the toner image formed on the photoconductor 21 to a transfer material such as paper, and a transfer material that is in close contact with the photoconductor 21 A separation unit having a separation electrode 25 for separation, a conveyance mechanism 27 for conveying the separated transfer material, and a fixing device 3 for fixing the toner image transferred to the surface of the transfer material
0, and a cleaning unit 28 that cleans residual toner by a cleaning blade that contacts the photoconductor 21.

In the image forming apparatus of this example, in order to apply a stable charging potential, feedback control is performed by detecting the surface potential of the photosensitive member 21 and using the detection signal. Specifically, a surface potential detecting means 31 for detecting the surface potential of the photoconductor 21 is provided at a downstream position of the charging device 22, and a charging current power supply 32 for supplying a charging current to a charging wire of the charging device 22. A surface potential signal from the surface potential detection unit 31 is input to a control unit 35 that controls both a power supply 33 for applying a grid voltage for setting the plate grid of the charging device 22 to a predetermined potential state, The charging current and the grid voltage are controlled in accordance with the surface potential signal.

By performing such feedback control, the charging device 22 is operated by the charging current and the grid voltage according to the surface potential state of the photosensitive member.
The photoconductor 21 can always be charged to the desired charging potential state. As a result, the surface layer of the photoconductor 21 is deteriorated by ozone and the film thickness is reduced over a long period of time, in addition to the features of the charging device itself. The variation of the charging potential due to the above can be changed and corrected to an appropriate charging potential. Therefore, this image forming apparatus further improves overall durability by stabilizing the charging potential.

[0095]

According to the present invention, in an image forming apparatus provided with an organic photoreceptor, a charging device for charging the organic photoreceptor has a plate-shaped grid, and the plate-shaped grid is formed of a perforated plate-shaped stainless steel. In particular, since the gold-plated layer is formed on a grid substrate made of aluminum, particularly, the gold-plated layer is formed directly on the surface of the grid substrate, so that the plate-shaped grid can be used for a long time. Also, since the gold plating layer does not peel off and has high durability, the charging device operating characteristics of the charging device become stable, and therefore, in the process of forming an electrostatic image on the organic photoconductor, the organic photoconductor is not used. Can always be stably charged to a desired charging state. Such a charging device is particularly preferable when the surface layer of the organic photoreceptor contains a siloxane-based resin having a crosslinked structure.

In the image forming apparatus of the present invention, when the photosensitive member is an amorphous silicon-based photosensitive member, the plate-like grid of the charging device is formed by forming a gold plating layer directly on the surface of the grid base material. With this structure, the gold-plated layer does not peel off even when used for a long period of time, and has high durability. Therefore, the amorphous silicon-based photoconductor is always stably charged as intended. It can be charged to a state.

In the image forming apparatus, a surface potential detecting means for detecting the surface potential of the photoreceptor is provided. Based on the information from the surface potential detecting means, a charging current supplied to the charging device and a grid voltage applied to the plate grid are provided. By controlling the above, the features of the above-described charging device can be sufficiently exhibited.

According to the method of manufacturing the charging device of the present invention, the gold plating layer of the plate grid is formed by the electroplating method using a pulse current. The formed gold plating layer has a dense and hard structure with few pinholes, and is uniform even if the layer thickness is thin, and has high adhesion to the stainless steel surface forming the grid base material. It becomes what has.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an example of a configuration of a charging device used in an image forming apparatus of the present invention.

FIG. 2 is an exploded perspective view of the charging device of FIG.

FIG. 3 is an explanatory diagram illustrating an example of a main part of the configuration of the image forming apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plate grid 2 charging wire 3 spring 4 support member 10 charging device 21 photoreceptor 22 charging device 23 developing device 24 transfer unit 25 separation unit 27 transport mechanism 28 cleaning unit 30 fixing device 31 surface potential detection means 32 charging power supply 33 Power supply for grid voltage application 35 Control means

Claims (9)

[Claims] An organic photoreceptor on which an electrostatic image is formed, a charging device for charging the organic photoreceptor, and a toner image formed by visualizing the electrostatic image formed on the organic photoreceptor. An image forming apparatus comprising: a developing device for forming; a transfer unit for transferring the toner image to a transfer material; and a fixing device for fixing the toner image transferred to the transfer material. An image forming apparatus comprising: a plate grid formed by forming a gold plating layer on a stainless steel grid base material. 2. The image forming apparatus according to claim 1, wherein the gold plating layer is formed directly on a surface of a perforated plate-shaped stainless steel grid base material. 3. The image forming apparatus according to claim 1, wherein the surface layer of the organic photoconductor contains a siloxane-based resin having a crosslinked structure. 4. An amorphous silicon-based photoconductor on which an electrostatic image is formed, a charging device for charging the amorphous silicon-based photoconductor, and a charging device formed on the amorphous silicon-based photoconductor. A developing unit that visualizes the electrostatic charge image to form a toner image, a transfer unit that transfers the toner image to a transfer material, and a fixing device that fixes the toner image transferred to the transfer material. In the image forming apparatus, the charging device is provided with a plate-shaped grid formed by directly forming a gold plating layer on a surface of a perforated plate-shaped stainless steel grid base material. 5. The image forming apparatus according to claim 1, wherein the thickness of the gold plating layer is 0.3 μm or more. 6. A surface potential detecting means for detecting a surface potential of the photoreceptor is provided, and based on information detected by the surface potential detecting means, a charging current supplied to a charging device and a charging current supplied to the plate-like grid are determined. The image forming apparatus according to claim 1, further comprising control means for controlling an applied grid voltage. 7. A method for manufacturing a charging device provided with a plate-like grid used in an image forming apparatus, comprising: a gold plating layer on a surface of a perforated plate-like stainless steel grid base material by an electrolytic plating method using a pulse current; A method for manufacturing a charging device for an image forming apparatus, wherein a plate grid is manufactured by forming a sheet. 8. The gold plating layer to be formed has a thickness of 0.3 μm.
The method for manufacturing a charging device for an image forming apparatus according to claim 7, wherein m is at least m. 9. An image forming apparatus having a charging device provided with a plate-like grid, wherein the plate-like grid of the charging device is gold-plated on a perforated plate-like stainless steel grid base material by an electrolytic plating method using a pulse current. An image forming apparatus comprising a layer formed.