JPH11119511A - Method for manufacturing charging member and charging member obtained by the method - Google Patents

Abstract

(57) [Problem] To reuse various charging rollers having deteriorated electric characteristics as they are, unevenness of the resistance value occurs on the surface due to contamination of the surface due to adhesion of toner and the like, and uneven charging occurs. A method for manufacturing a charging member for contacting or approaching a charging member and applying a voltage to the charging member to charge the surface of the charging member includes at least one layer. It is characterized by having a coating layer, removing the coating layer by dissolving it with an organic solvent, and forming the coating layer again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a charging member used in an electrophotographic apparatus, and a charging member manufactured by the method.

[0002]

2. Description of the Related Art Various charging members conventionally used in electrophotographic image forming apparatuses such as copiers, laser beam printers, and facsimile machines, for example, development charging rollers, transfer charging rollers, and primary charging rollers. Cannot use a defective product generated during manufacturing as a product.

[0003] Further, most of the above-mentioned various charging rollers are used up and have not been reused. Attempts have been made to reuse only a small number of metal rollers. For example, there is known a recycling method in which a roller is immersed in a cleaning solvent to remove dirt on the outer peripheral surface of the roller with a cleaning member such as a brush.

[0004]

Recently, ecology (the idea of coexisting gently with the global environment without abusing or polluting the global environment) has been spreading worldwide. From the standpoint of saving global resources and protecting the environment, the various charging rollers provided in electrophotographic devices, such as those described above, cannot be used as defective products that occur during manufacturing, or are mostly used up. Not being recycled was not a good thing.

Various charging rollers provided in an electrophotographic apparatus often have a multi-layer structure because of the need for multiple functions. In the case where the charging roller has a multilayer structure, means such as coating is generally used. When a layer is formed by coating, if a foreign material has been mixed into the coating during the preparation of the coating, or if a coating in which the binder resin and the conductive agent are not completely dispersed and dissolved is used, the surface of the layer formed by coating is used. Causes coating defects such as bumps. Currently, electrophotographic equipment is 600d
Since the resolution is higher than pi, if there are irregularities such as bumps on the surface of various charging rollers, the portions will have minute resistance unevenness, and uniform charging cannot be performed, which may cause image defects.

[0006] Most of the various charging rollers provided in the electrophotographic apparatus are made of synthetic resin, synthetic rubber, or the like, and the metal roller cleaning method described in the above-mentioned conventional recycling method is not used. For the following various reasons, it cannot be used as it is as a method for cleaning a roller made of synthetic resin or synthetic rubber.

(A) When a cleaning member such as a brush is used, the synthetic resin or synthetic rubber cracks, and the electrical resistance, hardness, surface roughness, roundness, straightness, slipperiness (friction coefficient), etc. Various functions required for this type of roller may be impaired.

Further, if various charging rollers are used for a long period of time, the following problem occurs.

(A) The charging roller has a problem in that the electrical characteristics of the charging roller deteriorate as the electrophotographic process is repeated many times and do not exhibit the same level of electrical characteristics as the initial stage. The decrease in the electrical characteristics is considered to be caused by deterioration of the surface of the charging roller due to the influence of ozone or the like generated by discharge during charging, friction of the surface of the charging roller due to contact with the member to be charged, and the like.
There is a case where the charging roller whose electric characteristics have been once deteriorated does not show much recovery of the electric characteristics even after the solvent washing as described above.

(B) When the various charging rollers whose electric characteristics are deteriorated as described above are reused without taking any means such as cleaning, some charging rollers, which are severely stained due to adhesion of a powder developer (toner) or the like, may be used. There is a roller, and unevenness of the resistance value is generated on the surface of the charging roller particularly in a low-temperature and low-humidity environment due to surface contamination, resulting in uneven charging. The charging roller having the reduced charging ability as described above is easily affected by surface contamination.

An object of the present invention is to provide a method for manufacturing a charging member which does not have the above-mentioned problems, and a charging member obtained by this method.

[0012]

SUMMARY OF THE INVENTION The present invention is a charging member having the following structure and a method for manufacturing the same.

(1) A method of manufacturing a charging member of a charging device in which a charging member is brought into contact with or close to a member to be charged, and a voltage is applied to the charging member to charge the surface of the member to be charged. A method for producing a charging member, comprising: at least one coating layer; removing the coating layer of the charging member by dissolving with an organic solvent; and forming a coating layer again.

(2) The pressure of the organic solvent is 1013 hPa
The method for producing a charging member according to (1), wherein the lower boiling point is 50 ° C. or more and 220 ° C. or less.

(3) A charging member obtained by the above manufacturing method.

(4) The charging member according to (3), wherein the charging member has at least a coating layer made of a non-crosslinkable solvent-soluble resin.

(5) The charging member according to (3), wherein the charging member has a 10-point average surface roughness of 15 μm or less.

(6) The volume resistivity of the charging member is 10 ⁴
The charging member according to (3), which has a range of from 10 to ^{12 12} Ωcm.

(7) The charging member according to (3), wherein the charging member has an ASKER-C hardness of 65 ° or less and a micro hardness of 85 ° or less.

(8) The charging member according to any one of (3) to (7), wherein the applied voltage is a DC voltage or an oscillating voltage.

(9) The oscillating voltage is a superimposed voltage of a DC voltage and an AC voltage having a peak-to-peak voltage that is at least twice the charging start voltage of the member to be charged when the DC voltage is applied ( The charging member according to 8).

The present invention makes effective use of resources in order to repair and use defective products generated during the manufacture of a charging roller used in an electrophotographic apparatus.

Further, the present invention is effective as a method for recycling and recycling a charging roller used in an electrophotographic apparatus.
The charging roller used in the electrophotographic apparatus has a problem that the roller surface is deteriorated due to the influence of ozone or the like generated during charging and friction with the member to be charged while the electrophotographic process is repeated many times. Further, there is also a problem that the powder developer (toner) adheres to the surface, and the toner adhered to the surface causes uneven resistance on the surface of the charging roller, causing uneven charging. It is not easy to completely remove the toner and the like adhering to the surface of the charging roller. In the present invention, in the recycling and recycling of the charging roller having such a problem, the outer peripheral surface of the deteriorated roller is dissolved and removed by using an organic solvent to remove the layer forming the surface, and the charging is performed by forming the coating layer again. The purpose is to restore the electrical properties of the member to a sufficient state, and to enable reuse as a charging roller.

In the method for producing a charging member according to the present invention, as a coating method, means such as dip coating (dipping coating), spray coating, roll coating, and electrostatic coating can be used. The charging member is applied with a coating material by these coating means and then dried to form a coating layer. As described above, if there is coating failure, bumps and the like may occur on the surface of the charging member. When the binder resin of the coating layer formed by coating is a cross-linking type or contains a cross-linking agent,
In many of them, the binder resin is crosslinked by heating in a drying step after application of the paint. Although the coating layer has a strong structure due to crosslinking, it has been very difficult to repair the coating layer in which coating failure has occurred. However, in the present invention, since the binder resin constituting the coating layer is made of a non-crosslinked resin, the coating layer can be dissolved in an organic solvent even after drying, and even if a problem occurs due to coating, The coating layer can be easily dissolved and removed. Therefore, if the coating layer is formed again, the defective product can be revived as a good product.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the charging member of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural view of an example of an electrophotographic apparatus (laser beam printer) using a contact charging device using the charging member of the present invention as a primary charging means of an image carrier, and FIG. Another example of a member is shown.

The member to be charged is a rotating drum type electrophotographic photosensitive member (hereinafter, also referred to as "photosensitive drum 1"), and has a predetermined peripheral speed (process speed) clockwise in FIG.
Is driven to rotate. 1a is a conductive drum base made of aluminum or the like of the photosensitive drum 1, and 1b is a photosensitive layer formed on the outer peripheral surface of the drum base 1a.

The charging member is a roller body (hereinafter, referred to as “charging roller 2”) arranged in pressure contact with a predetermined pressing force in parallel with the drum generatrix direction of the photosensitive drum 1.
It rotates following the rotation of.

The charging roller 2 includes a conductive core 2a for applying a DC voltage or a superimposed voltage of a DC voltage and an AC voltage, a conductive elastic layer 2b for providing elasticity and conductivity, and a resistance of a charging member as required. When a coating layer 2d (resistance control layer) to be controlled is formed thereon and a resistance control layer is provided, a coating layer 2c (surface layer) is often provided outside the resistance control layer. In the present invention, the surface in which defects such as coating unevenness and irregularities due to coating failure have occurred, or the surface that has been deteriorated by electric discharge or the like is removed by dissolving with an organic solvent, and the coating layer is re-formed by re-coating to regenerate. Things.

As shown in FIG. 2, the charging roller prior to reproduction may have a configuration including a conductive elastic layer 2b without a resistance control layer and a surface layer 2c.

The conductive core 2a, conductive elastic layer 2b, resistance control layer 2d, and surface layer 2c of the charging roller 2 of this embodiment will be described later.

A power source 3 for applying a voltage to the charging roller 2 is provided.
By applying a predetermined voltage to a, the surface of the rotating photosensitive drum 1 is charged to a predetermined potential by a contact charging method.

The voltage applied to the charging roller 2 may be a DC voltage only or a DC voltage with an oscillating electric field such as an AC voltage superimposed thereon. In terms of uniform charging,
The case where the oscillating electric field is superimposed is more advantageous.

Exposure means (not shown) for forming an electrostatic latent image by exposing the surface of the photosensitive drum 1 uniformly charged to a predetermined potential to a predetermined potential by the charging roller 2 in accordance with image information of a document. A developing device 5 for forming a toner image by attaching toner to the electrostatic latent image (only the direction of light is indicated by arrow 4);
A transfer charger 7 for transferring the toner image on the photosensitive drum to the transfer material P supplied from the paper feed cassette 6, a cleaning device 9 for removing residual toner on the photosensitive drum 1 after the transfer, and preparing for the next primary charging; A not-shown pre-exposure unit (only the direction of light is indicated by an arrow 10) for removing charges on the photosensitive drum 1 is provided. Further, a fixing device 8 for fixing the toner image transferred onto the transfer material P to the transfer material P is disposed downstream of the transfer charger 7.

In the present invention, the conductive core 2a is made of iron,
A round bar of a metal material such as copper, stainless steel, aluminum, and nickel can be used. Further, these metal surfaces may be subjected to plating treatment for the purpose of rust prevention and imparting scratch resistance, but it is necessary that the conductivity is not impaired.

In the charging roller 2, the conductive elastic layer 2b is provided with a power supply to the photosensitive drum 1 as an object to be charged, and an appropriate conductivity for ensuring good uniform adhesion of the charging roller 2 to the photosensitive drum 1. It has elasticity. In addition, in order to ensure uniform adhesion between the charging roller 2 and the photosensitive drum 1, the conductive elastic layer 2b may be formed in a shape that is thickest at the center and thinner toward both ends, a so-called crown shape. . Generally used charging roller 2
By applying a predetermined pressing force to both ends of the cored bar 2a, the photosensitive drum 1
Since the pressing force at the central portion is small and the pressure at both ends is large, there is no problem if the straightness of the charging roller 2 is sufficient. In some cases, density unevenness may occur in an image corresponding to a part. The crown shape is formed to prevent this.

The conductivity of the conductive elastic layer 2b is adjusted by adding a conductive agent such as carbon black to an elastic material such as rubber. The elasticity is adjusted by adding a process oil, a plasticizer, or the like. Specific elastic materials of the conductive elastic layer 2b include, for example, natural rubber, ethylene-propylene-diene rubber (EPDM), styrene-butadiene rubber (SBR), silicone rubber (Si), urethane rubber (U), isoprene rubber ( IR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NB
R), synthetic rubber such as chloroprene rubber (CR), and resins such as polyamide resin, polyurethane resin and silicone resin. Further, a foam of the above-described elastic material may be used for the conductive elastic layer 2b.

The resistance control layer 2d can be provided to control the resistance of the charging member. As a specific material of the resistance control layer 2d, a polyamide resin, a polyurethane resin,
Resins such as acrylic resin, fluorine resin, silicone resin,
Further, epichlorohydrin rubber, urethane rubber, chloroprene rubber, acrylonitrile rubber and the like can be mentioned. Conductive particles such as carbon black and carbon graphite, conductive metal oxides such as conductive tin oxide, conductive titanium oxide and conductive zinc oxide, alkali metal salts, etc. Alternatively, a conductive agent such as an ammonium salt can be dispersed.

The surface layer 2c can be provided to prevent bleed-out of the plasticizer and the like in the conductive elastic layer 2b to the surface of the charging roller, and to ensure the slipperiness of the charging roller surface and prevent dirt. As a specific material of the surface layer 2c, a resin such as a non-crosslinkable solvent-soluble polyamide resin, an acrylic resin, a fluororesin, and a silicon resin is used. In order to make the surface layer 2c also have appropriate conductivity,
Carbon black, conductive particles such as carbon graphite, conductive tin oxide, conductive titanium oxide, conductive zinc oxide and other conductive metal oxides, or alkali metal salts,
A conductive agent such as an ammonium salt can be dispersed.

The charging member in which the surface layer 2c is made of a non-crosslinkable solvent-soluble resin is a charging member that can be recycled and regenerated according to the present invention.

The volume resistivity of the charging member in the present invention is 10 as measured according to JIS K 6911.
It is preferably in the range of ⁴ to 10 ¹² Ωcm. When the volume resistivity of the charging member is less than 10 ⁴ Ωcm, when a pinhole is generated on the photosensitive drum for some reason, the pinhole moves to a charging area which is a nip portion between the charging member and the photosensitive member. Leakage occurs between the pinhole of the drum and the voltage of the power supply unit drops significantly. For this reason, when this leak occurs, charging failure occurs in the entire longitudinal direction of the nip portion between the charging member and the photosensitive drum, and in an actual image, black band-shaped image unevenness in reverse development and white band-shaped image unevenness in regular development are caused every rotation cycle of the photosensitive drum. And image quality is degraded. If the volume resistivity of the charging member exceeds 10 ¹² Ωcm, the resistance of the charging member is too high to charge the photosensitive drum to a predetermined potential, resulting in poor charging. Increasing the supply voltage accordingly can solve this problem, but is very inefficient and impractical in practice.

When the charging member is in contact with or close to the photosensitive drum, if the surface of the charging member is rough, unevenness of the surface of the charging member may cause slight charging unevenness, resulting in image failure. Therefore, the surface of the charging member is preferably smooth, and the ten-point average surface roughness Rz in the JIS B0601 surface roughness standard is preferably 15 μm or less, more preferably 10 μm or less.

In the present invention, the hardness is measured by ASKER
The test was carried out in a 23.5 ° C./60% environment using a −C hardness meter and a micro hardness meter MD-1 (both manufactured by Kobunshi Keiki Co., Ltd.)

The measuring method using the ASKER-C hardness tester is as follows. A charging roller is placed on a metal plate, a metal block is placed on the charging roller, and the roller is easily fixed so as not to roll. An ASKER-C hardness tester is pressed with a load of 1 kg so as to accurately hit the center of the charging roller, and the value after 5 seconds is read. The average is calculated by measuring three points each in the circumferential direction at both ends and the center part at a position 40 mm from the rubber end of the charging roller, for a total of nine points.

In the case of a micro hardness tester, the value is a value measured in the peak hold mode, and the measurement terminal is made to vertically contact the center of the charging roller as in the case of the above-mentioned ASKER-C hardness. The measurement position and the number of measurements are ASKER-C
The average value of nine points is calculated in the same manner as in the case of.

The hardness of the charging member of the present invention is 6 in ASKER-C hardness measured according to the above hardness measuring method.
It is preferable that it is 5 ° or less and the micro hardness is 85 ° or less. When the ASKER-C hardness exceeds 65 °, the generation of charging noise becomes annoying if an oscillating voltage is used as the applied voltage. The micro hardness is 85.
°, the toner fuses on the photoreceptor,
It appears as a spotty image defect.

The boiling point of the organic solvent used in the regeneration operation of the present invention is preferably 50 ° C. or more and 220 ° C. or less under a pressure of 1013 hPa. Boiling point is 50 ℃
When less than an organic solvent (eg, diethyl ether) is used, the solvent volatilizes violently at room temperature, so that the consumption of the solvent increases and the cost increases. There is also a problem that the size of the device for safety measures is increased. On the other hand, when an organic solvent (for example, quinoline) having a boiling point of more than 220 ° C. is used, it cannot be easily volatilized from the surface of the charging member in the drying step, so that the drying temperature is increased or the drying time is lengthened. Is required, so that the efficiency is reduced. In addition, since an organic solvent having a high boiling point takes a long time to dry, the organic solvent may permeate into the charging member and may remain. If the organic solvent remains on the charging member without drying, there is a risk of contaminating the photoconductor.

[0048]

Embodiments of the present invention will be described below.

Example 1 According to the present invention, a charging roller 2 as a charging member was prepared by the following operation.

SBR 100 parts by weight Carbon black 30 parts by weight Zinc oxide 5 parts by weight Fatty acid 2 parts by weight The above materials were mixed in a closed mixer adjusted to 60 ° C.
After kneading for 0 minutes, 30 parts by weight of a naphthenic oil is added to 100 parts by weight of SBR, and the mixture is kneaded for 20 minutes with a closed mixer cooled to 20 ° C. to prepare a raw material compound. Further, 0.5 parts by weight of sulfur as a vulcanizing agent and 1 part by weight of a thiazole type and 1 part by weight of a thiuram type as a vulcanization accelerator are added to the raw material compound with respect to 100 parts by weight of SBR of the raw rubber, and the two rolls cooled to 20 ° C. Knead for 10 minutes in a machine. Using this compound, the conductive elastic layer 2b was vulcanized and formed into a roller shape around a φ6 stainless steel cored bar 2a by a press molding machine so as to have an outer diameter of φ12.

Next, the following resistance control layer 2d was formed on the conductive elastic layer 2b.

As a material for the resistance control layer 2d, 100 parts by weight of a polyurethane resin 0.7 parts by weight of lithium perchlorate 3 parts by weight of carbon black are dispersed and dissolved in a methyl ethyl ketone (MEK) solvent to prepare a paint for a resistance control layer. This paint was applied on the conductive elastic layer 2b by dipping to form a resistance control layer 2d having a thickness of 100 μm.

Further, a surface layer 2c shown below was formed on the resistance control layer 2d.

As a material for the surface layer 2c, 100 parts by weight of alcohol-soluble copolymerized nylon (non-crosslinked type) and 25 parts by weight of conductive tin oxide are decomposed and dissolved in a methanol solvent to prepare a coating solution for the surface layer. The coating liquid was applied on the resistance control layer 2d by dipping to form a surface layer 2c having a thickness of 20 μm and dried to form the charging roller 2. However,
On the surface of the obtained charging roller 2, there was a coating spot having a diameter of about 1 mm. The charging roller having poor coating was immersed in a methanol solvent for 600 seconds to dissolve and remove the surface layer having coating irregularities. The charging roller from which the surface layer was dissolved and removed was dried for 30 minutes by a dryer adjusted to a temperature of 90 ° C. Then, the surface layer was formed again by using the surface layer paint. In this case, the charging roller was obtained without any coating irregularities.

With respect to the obtained charging roller, a 10-point average surface roughness was measured. Table 1 shows the results.

The resistance value of the charging roller 2 is set to 23.degree.
Under a temperature of 5 ° C. and a humidity of 50% (environment 1), an aluminum foil having a width of 10 mm is tightly wound around the outer periphery of the charging roller 2, and a DC voltage (250 V) is applied between the support and the aluminum foil to measure the resistance of the resistance meter “HIOKI”. 3119 DEGITAL MΩ HI
TESTER (Hioki Electric Co., Ltd.) ". Table 2 shows the results.

The hardness of the charging roller 2 was measured according to the method described above. Table 3 shows the results.

Further, the obtained charging roller 2 is located at the position of a primary charger of a process cartridge (model name "EP-E toner cartridge") used in a laser beam printer (trade name "LBP-8 Mark IV" Canon Inc.). The image was evaluated by visually observing the images obtained at the initial stage and after the end of 6000 images, and the results were shown in Table 4. The results are shown in Table 4. The symbol が indicates that the obtained image was good, the symbol △ indicates that the image was practical, and the symbol X indicates that the image was impractical.

The above-mentioned image output durability test was conducted at a temperature of 2
3.5 ° C, humidity 50% (environment 1) and temperature 15 ° C,
Humidity 10% (environment 2), temperature 30 ° C, humidity 80%
(Environment 3).

After the endurance test, the charging roller 2 '(before reproduction, used) was taken out from the process cartridge, and the recycling of the charging roller 2 was attempted in accordance with the present invention. The charging roller 2 was immersed in a methanol solvent for 600 seconds to remove the deteriorated surface. After removing the surface layer, it was dried for 30 minutes by a dryer adjusted to a temperature of 90 ° C. The surface layer shown below was recoated on the dried charging roller, and the charging roller 2 was regenerated.

As a material for the surface layer 2c, 100 parts by weight of alcohol-soluble copolymerized nylon (non-crosslinked type) and 25 parts by weight of conductive tin oxide are dispersed and dissolved in a methanol solvent to prepare a coating solution for the surface layer. This coating solution was applied on the dried charging roller by a dipping method to form a 16 μm surface layer 2c, thereby forming a charging roller 2 (reproduction roller).

The obtained charging roller was measured for 10-point average surface roughness. Table 1 shows the results.

The resistance value of the obtained charging roller 2 was adjusted to a temperature of 23.5 ° C. and a humidity of 50% (environment 1) by winding an aluminum foil of 10 mm width tightly around the outer periphery of the charging roller 2 to form a support. DC voltage (250v) is applied between the resistance meter and the aluminum foil, and the resistance meter "HIOKI 3119 DEGITAL"
MΩ HI TESTER (Hioki Electric Co., Ltd.) ”. Table 2 shows the results.

The hardness of the charging roller was measured according to the method described above. Table 3 shows the results.

The charging roller 2 (reproducing roller) is incorporated as a primary charger of an unused process cartridge (product name: EP-E toner cartridge), and a laser beam printer (product name "LBP") as shown in FIG. -8
Mark IV "Canon Inc.)
An image endurance test was performed for printing a plurality of sheets. Initial and 60
The image was evaluated by visually observing the image obtained after the endurance of 00 sheets. Table 5 shows the results.

The above-mentioned image output durability test was conducted at a temperature of 2
3.5 ° C, humidity 50% (environment 1) and temperature 15 ° C,
Humidity 10% (environment 2), temperature 30 ° C, humidity 80%
(Environment 3).

(Example 2) In Example 1, the surface layer 2
As a material used for c, 100 parts by weight of polyvinylidene fluoride resin and 30 parts by weight of conductive titanium oxide were dispersed and dissolved in an N, N-dimethylformamide solvent to prepare a coating solution for a surface layer. This coating liquid was applied on the resistance control layer 2d by dipping to form a film having a thickness of 15 μm.
Was formed, and a charging roller 2 (before reproduction) was obtained.
Using this charging roller 2, evaluation and an image output durability test were performed in the same manner as in Example 1. Tables 1, 2, 3 and 4 show the results.
Shown in

In order to remove the deteriorated portion of the surface of the charging roller 2 after the durability test, 48 parts of N-methylpyrrolidone solvent was used.
After immersion for 0 second, 3
Dry for 0 minutes.

The surface layer 2 shown below is applied to the dried charging roller.
c was recoated.

As a material for the surface layer 2c, 100 parts by weight of polyvinylidene fluoride resin and 30 parts by weight of conductive titanium oxide were dispersed and dissolved in an N, N-dimethylformamide solvent to prepare a coating solution for the surface layer. The coating liquid was applied on the dried charging roller by a dipping method to form a 15 μm surface layer 2c, and the charging roller 2 was regenerated. The obtained reproduction charging roller 2 was evaluated in the same manner as in Example 1.
The results are shown in Tables 1, 2, 3 and 5.

Example 3 A two-layer structure comprising a surface layer 2c and a conductive elastic layer 2b as shown in FIG. 2 in the same manner as in Example 1 except that the resistance control layer 2d was not provided. A charging roller having a configuration (before reproduction) was prepared.

Using the obtained charging roller, evaluation and an image output durability test were performed in the same manner as in Example 1. The results are shown in Tables 1, 2, 3 and 4.

Using the charging roller after the image output durability test, a reproducing operation was performed in the same manner as in Example 1. The obtained reproduction roller was also subjected to the same evaluation and durability test as in Example 1. The results are shown in Tables 1, 2, 3 and 5.

Example 4 The material used for the resistance control layer 2d in Example 1 was 100 parts by weight of alcohol-soluble copolymerized nylon (non-crosslinked type) 20 parts by weight of conductive tin oxide 0.5 part by weight of lithium perchlorate The resistance control layer 2d having a thickness of 120 μm was formed by a dipping method using a methanol solvent for coating preparation.
However, coating unevenness occurred on the surface of the charging roller after the formation of the resistance control layer 2d. The charging roller having poor coating was dipped in a methanol solvent for 600 seconds to dissolve and remove the resistance control layer having poor coating. The charging roller from which the resistance control layer had been removed was dried for 30 minutes by a dryer adjusted to a temperature of 90 ° C. Thereafter, the resistance control layer was formed again by coating. This time, there were no coating unevenness or coating irregularities.

Next, a surface layer 2c as shown below was formed on the resistance control layer 2d.

As a material for the surface layer 2c, 100 parts by weight of polyvinylidene fluoride resin and 15 parts by weight of conductive tin oxide were prepared by coating with a N, N-dimethylformamide solvent, and the surface having a thickness of 7 μm was spray-coated. Except that the layer 2c was formed, the other steps were the same as those in the example 1.

Using the obtained charging roller, evaluation and an image output durability test were performed in the same manner as in Example 1. Table 1 shows the results.
The results are shown in Tables 2, 3 and 4.

Comparative Example 1 The surface layer 2c of Example 1
The material to be used is: polyol 100 parts by weight Isocyanate (crosslinking agent) 5 parts by weight Conductive tin oxide 25 parts by weight A methyl ethyl ketone solvent is used for paint preparation to form a 22 μm thick surface layer, and the temperature is adjusted to 100 ° C. A charging roller was prepared in the same manner as in Example 1 except that the charging roller was dried with a dryer for 60 minutes. The occurrence of coating dust was observed on the surface of the obtained charging roller. An acetone (solubility coefficient 9.9) having a similar solubility coefficient to the polyurethane resin (solubility coefficient 10.0) constituting the surface layer is used as an organic solvent for dissolving the surface in order to regenerate the charging roller that has generated the coating bumps. Used as The charging roller with the coating was immersed in an acetone solvent for 1,800 seconds, but the surface layer was swollen but could not be dissolved. Therefore, it was not possible to remove the surface layer where the coating was generated and to re-form the surface layer.

(Comparative Example 2) After a process cartridge (model name "EP-E toner cartridge") used in a laser beam printer (trade name "LBP-8Mark IV" Canon Inc.) has output 6,000 images, The charging roller 2 'was taken out of the process cartridge, and a powder developer (toner) was adhered to the surface of the charging roller 2'.

In Comparative Example 2, the 10-point average surface roughness, resistance value,
The hardness was measured and evaluated. The results are shown in Tables 1, 2, 3 and 4.

Unused process cartridge (trade name: EP-E toner cartridge) without removing the charged roller 2 ′ without cleaning and surface treatment etc.
And used as the charging roller 2 at the position of the primary charger of the laser beam printer "LBP-8 Mark IV (Canon Inc.)" as shown in FIG. Was. Table 5 shows the results.

In environment 2, the second half of the image output durability test (4
(500 sheets), in the halftone image area, charging unevenness due to contamination of the charging roller 2 'was slightly generated.

(Comparative Example 3) A process cartridge (model name "EP-E toner cartridge") used in a laser beam printer (trade name "LBP-8 Mark IV" Canon Inc.) is used after 6,000 images have been output. The charging roller 2 'was taken out of the process cartridge, and a powder developer (toner) was adhered to the surface of the charging roller 2'.

In order to clean dirt such as toner adhered to the surface of the charging roller 2 ′, the charging roller 2 ′ is immersed in a cleaning solvent (methyl ethyl ketone) and cleaned using a brush as a cleaning member. Attempted recycling.

After the cleaning, countless small scratches were observed on the surface of the charging roller (confirmed visually). These scratches are considered to be brush scratches.

The charged roller 2 'after cleaning is incorporated in a process cartridge (trade name: EP-E toner cartridge), and primary charging of a laser beam printer (LBP-8Mark IV, Canon Inc.) as shown in FIG. 1 is performed. When an image was formed using the charging roller 2 located at the position of the charging device, image defects corresponding to scratches on the surface of the charging roller were observed.

(Comparative Example 4) A process cartridge (model name "EP-E toner cartridge") used in a laser beam printer (trade name "LBP-8 Mark IV" Canon Inc.) was used to output 8000 images. The charging roller 2 'was taken out of the process cartridge, and a powder developer (toner) was adhered to the surface of the charging roller 2'.

In order to clean dirt such as toner adhered to the surface of the charging roller 2 ', the surface of the roller is cleaned using a felt (cleaning member) holding a cleaning solvent (methyl ethyl ketone), and recycling recycling is attempted. Was.

The charged roller 2 'after cleaning is incorporated in a process cartridge (trade name: EP-E toner cartridge), and a primary part of a laser beam printer (LBP-8Mark IV, Canon Inc.) as shown in FIG. 1 is used. When an image was formed using the charging roller 2 located at the position of the charger, an uneven density was generated in the obtained image. It is considered that the density unevenness occurred because the function of the charging roller could not be sufficiently restored even though the recycling and regeneration was performed using the solvent washing. The fact that the function of the charging roller has not recovered can also be seen from the roller resistance value measurement results in Table 2. The resistance especially at the center of the roller is higher than in the initial stage.

[0090]

[Table 1]

[0091]

[Table 2]

[0092]

[Table 3]

[0093]

[Table 4]

[0094]

[Table 5]

[0095]

As described above, according to the present invention, a charging roller having a defect such as a coating spot generated at the time of manufacturing is repaired and regenerated, which leads to effective use of earth resources. In addition, it enables recycling of the charging roller used in the electrophotographic apparatus, and contributes to saving of global resources and environmental protection.

Further, since the charging roller according to the present invention sufficiently secures electrical characteristics as a charging member in an electrophotographic apparatus, stable output image quality and durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an electrophotographic apparatus in which a contact charging device using a charging member of the present invention is a primary charging unit of an image carrier.

FIG. 2 is a schematic configuration diagram of a contact-type charging member according to another embodiment of the present invention.

[Description of Signs] 1 Charged body (photosensitive drum) 1a Conductive drum substrate 1b Photosensitive layer 2 Charging member (charging roller) 2a Conductive core 2b Conductive elastic layer 2c Coating layer (surface layer) 2d Coating layer (resistance) Control layer) 3 Power supply 4 Exposure means 5 Developing device 6 Paper feed cassette 7 Transfer charger 8 Fixing device 9 Cleaning device 10 Pre-exposure device P Transfer material

Claims (9)

[Claims] 1. A method for manufacturing a charging member in which a charging member is brought into contact with or in proximity to a member to be charged and a voltage is applied to the charging member to charge the surface of the member to be charged, wherein the charging member has at least one layer. A method for producing a charging member, comprising a coating layer, removing the coating layer by dissolving the coating layer with an organic solvent, and forming the coating layer again. 2. The organic solvent has a boiling point of not less than 50 ° C. and not more than 220 ° C. under a pressure of 1013 hPa.
3. The method for producing a charging member according to item 1. 3. A charging member obtained by the manufacturing method according to claim 1. 4. The charging member according to claim 3, wherein the charging member has a coating layer made of at least a non-crosslinkable solvent-soluble resin. 5. The charging member has a 10-point average surface roughness of 1
4. The charging member according to claim 3, wherein the thickness is 5 μm or less. 6. The charging member having a volume resistivity of 10 ⁴ to 1
0 charging member according to claim 3 in the range of ¹² [Omega] cm. 7. The charging member having an ASKER-C hardness of 6
The charging member according to claim 3, wherein the charging member has a micro hardness of 5 ° or less and a micro hardness of 85 ° or less. 8. The charging member according to claim 3, wherein the applied voltage is a DC voltage or an oscillating voltage. 9. The charging method according to claim 8, wherein the oscillating voltage is a superimposed voltage of a DC voltage and an AC voltage having a peak-to-peak voltage that is at least twice the charging start voltage of the member to be charged when the DC voltage is applied. Element.