JP2015221417A - Washing apparatus and washing method for electrically conductive substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a washing apparatus for an electrically conductive substrate that can remove not only sticking matter such as chips and oil contents, but also foreign matter due to microorganisms to achieve excellent washing.SOLUTION: There is provided a washing apparatus for an electrically conductive substrate that includes a washing tank which stores a water type cleaning fluid, an air bubble supply part which supplies air bubbles including microbubbles including no oxygen into the cleaning fluid, and a substrate transfer part which dips the electrically conductive substrate for an electrophotographic sensitive body in the cleaning fluid supplied with the air bubbles.

Description

  The present invention relates to a cleaning apparatus and a cleaning method for a conductive substrate for an electrophotographic photosensitive member.

  When cutting a conductive substrate for an electrophotographic photosensitive member (hereinafter sometimes simply referred to as “conductive substrate”), processing oil, lubricating oil, rust preventive oil, or the like is used. Therefore, oil components such as kerosene are attached to the conductive substrate after processing, and in addition, human-derived foreign matters such as cutting powder, dust in the air, sebum and saliva during handling, and the like are attached. For this reason, it is necessary to apply a photosensitive layer on the conductive substrate after removing these deposits by washing.

  Cleaning methods for conductive substrates include cleaning using chlorofluorocarbon, chlorinated solvents, organic solvents, water-based cleaning agents, or pure water. Considering the effects on the global environment and the human body, water-based cleaning methods are currently available. A cleaning method using a cleaning agent or pure water is the mainstream.

  In the dip coating method in which the photosensitive layer is coated on the surface of the conductive substrate, if the surface of the conductive substrate, which is a pretreatment, is insufficiently cleaned, oil, dust, etc. remain on the surface, and repellency, Cause coating defects. Defects generated on such an electrophotographic photoreceptor (hereinafter sometimes referred to simply as “photoreceptor”) may cause black spots, white spots, uneven halftone images, etc. in the copy image, resulting in improved image quality. Adversely affect.

In view of this, bubble cleaning by air blow has been proposed in order to improve cleaning efficiency (for example, see Patent Document 1).
In recent years, microbubbles have attracted attention (see, for example, Patent Document 2). A normal bubble rises up to the water surface and disappears, whereas a microbubble has a characteristic that it stays in the liquid for a long time. In addition, it has characteristics that are not found in normal bubbles, such as high internal pressure of bubbles and negative charging. Since microbubbles have a high cleaning effect, most of them, such as oil, fibrous dust and chips, can be removed.

JP-A-5-216254 JP 2006-267443 A

However, there is a transparent foreign substance as a cause of the occurrence of the defect. This transparent foreign matter generates a white spot in the copy image, which is a major factor in reducing the production yield of the photoreceptor.
As a result of intensive studies on how transparent foreign matter adheres to the photoreceptor, the present inventor does not adhere during cutting or handling of the conductive substrate, but adheres in the cleaning step of the conductive substrate. Turned out to be.
Therefore, it seemed that if microbubbles of air were supplied into the cleaning liquid, the cleaning power was improved and the transparent foreign matter adhering to the conductive substrate was removed. I found out.

As a result of various analyses, it was found that transparent foreign substances are substances discharged by microorganisms such as Bacillus subtilis and red yeast that are usually present in water.
Microbubbles have been reported to be sterilized by cation radicals generated when bubbles are ruptured and have a strong cleaning ability. On the other hand, dissolved bubbles increase the amount of dissolved oxygen and activate the activity of microorganisms. It also has the effect of becoming. Therefore, it is known that it is also used for water purification by microorganisms.
That is, it has been clarified that microbubbles activate microorganisms in the water and promote more and more transparent foreign matter discharge.

  As a countermeasure, sterilization with ozone microbubbles can be considered, but use in a released washing tank is not preferable because it requires treatment of ozone after use. Therefore, by using bubbles that do not contain oxygen so that microorganisms do not grow, the inventors have succeeded in obtaining a strong cleaning effect while suppressing the generation of transparent foreign matters, and have completed the present invention.

Thus, according to the present invention, a cleaning tank that contains an aqueous cleaning solution, a bubble supply unit that supplies bubbles that do not contain oxygen in the cleaning solution, and an electrophotographic photosensitive member in the cleaning solution that is supplied with the bubbles. An apparatus for cleaning a conductive substrate is provided that includes a substrate transfer section for immersing the conductive substrate.
Further, according to another aspect of the present invention, there is provided a method for cleaning a conductive substrate including a step of immersing a conductive substrate for an electrophotographic photosensitive member in an aqueous cleaning solution to which bubbles containing no oxygen are supplied. The

  According to the present invention, by rinsing in pure water or ion-exchanged water in which bubbles containing no oxygen are generated, the activation of microorganisms is prevented without increasing the oxygen concentration in the liquid, resulting in microorganisms. It is possible to prevent adhesion of transparent foreign matters.

It is a schematic block diagram which shows Embodiment 1 of the washing | cleaning apparatus of the electroconductive base | substrate of this invention. It is a schematic block diagram which shows the bubble supply part in the washing | cleaning apparatus of Embodiment 1. FIG. 3 is a schematic cross-sectional view illustrating an example of an electrophotographic photosensitive member using a conductive substrate cleaned by the cleaning apparatus of Embodiment 1. FIG. 4 is a partially enlarged schematic cross-sectional view of the electrophotographic photosensitive member of FIG. 3. FIG. 4 is a schematic diagram illustrating an example of an image forming apparatus including the electrophotographic photosensitive member of FIG. 3. It is a photograph of transparent foreign substances derived from microorganisms. It is the photograph of the foreign material of a chip. It is a photograph of the foreign material of a cellulose fiber.

  The cleaning apparatus for a conductive substrate according to the present invention includes a cleaning tank that stores an aqueous cleaning liquid, a bubble supply unit that supplies bubbles containing microbubbles not containing oxygen in the cleaning liquid, and the cleaning liquid supplied with the bubbles. And a substrate transfer section for immersing a conductive substrate for the electrophotographic photosensitive member.

The conductive substrate cleaning apparatus of the present invention may be configured as follows.
(1) The bubble supply unit may be configured to generate bubbles including microbubbles having an area average diameter of 0.1 to 100 μm.
In this way, a higher cleaning effect by the microbubbles can be obtained, and in particular, it is effective for removing foreign matters such as oil, fibrous dust, and chips.

(2) The bubble supply unit has a bubble generator and a gas supply source that supplies one or more gases selected from nitrogen, carbon dioxide, argon, and helium to the bubble generator. May be.
If it does in this way, a bubble generation part can be constituted using a commercial bubble generator and a commercial gas supply source.

(3) The bubble supply unit introduces the cleaning liquid in the cleaning tank into the bubble generator, and generates microbubbles in the cleaning liquid introduced into the bubble generator so as to be contained in the cleaning liquid in the cleaning tank. It may be configured to supply.
In this way, since the microbubbles can be generated using the cleaning liquid in the cleaning tank, the cleaning liquid can be saved.

(4) The cleaning tank includes a cleaning tank that stores an aqueous cleaning liquid for main cleaning including a surfactant, and a cleaning tank that stores an aqueous cleaning liquid for rinsing that does not include a surfactant. ,
The bubble supply unit may supply bubbles made of a cleaning gas not containing oxygen in the rinsing aqueous cleaning liquid.
In this way, the deposits remaining on the surface of the conductive substrate drawn out from the main cleaning aqueous cleaning liquid are removed from the rinsing aqueous cleaning liquid supplied with bubbles of cleaning gas not containing oxygen. Can be effectively removed. In addition, since bubbles of cleaning gas not containing oxygen are supplied into the rinsing water-based cleaning liquid, the activation of microorganisms in the rinsing cleaning liquid, which is the final finish of cleaning, is suppressed and a clean state is maintained. This is preferable.

(5) An ultrasonic oscillator that oscillates ultrasonic waves may be further provided in at least one of the aqueous cleaning liquid for main cleaning and the aqueous cleaning liquid for rinsing.
In this way, the cleaning effect can be further enhanced.

The method for cleaning a conductive substrate of the present invention includes a step of immersing the conductive substrate for an electrophotographic photosensitive member in an aqueous cleaning solution to which bubbles containing no oxygen are supplied.
The method for cleaning a conductive substrate of the present invention may be configured as follows.
(I) The amount of dissolved oxygen in the cleaning liquid during cleaning may be 2 mg / L or less.
In this way, the activity activation of microorganisms in the aqueous cleaning liquid can be effectively suppressed. As a result, it is possible to effectively suppress image defects due to white spots caused by transparent foreign matters caused by microorganisms. In addition, the lower the dissolved oxygen content of the cleaning liquid at the time of cleaning, the better.

(II) The bubbles may have an area average diameter of 0.1 μm to 100 μm.
In this way, a higher cleaning effect by the microbubbles can be obtained, and in particular, it is effective for removing foreign matters such as oil, fibrous dust, and chips.

(III) The bubbles may be composed of one or more gases selected from nitrogen, carbon dioxide, argon and helium.
If it does in this way, a commercially available gas cylinder can be utilized as cleaning gas which does not contain oxygen.

(IV) further includes a step of immersing and cleaning the conductive substrate in an aqueous cleaning solution for main cleaning containing a surfactant as an initial cleaning step;
You may supply the said bubble in a washing | cleaning liquid in the washing | cleaning process after the said 1st washing | cleaning process.
In this way, after the first cleaning step using a surfactant, the conductive substrate can be rinsed and finished with a cleaning solution supplied with bubbles that do not contain oxygen as a rinsing step. Fibrous dust and chips, transparent foreign matters caused by microorganisms and the like can be effectively removed, and a high cleaning effect can be obtained.

(V) Ultrasonic waves may be oscillated in the cleaning liquid.
In this way, the cleaning effect can be further enhanced.

  Hereinafter, embodiments of a cleaning apparatus and a cleaning method for a conductive substrate according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram showing a first embodiment of a conductive substrate cleaning apparatus of the present invention, and FIG. 2 is a schematic configuration diagram showing a bubble supply unit in the cleaning apparatus of the first embodiment. 3 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member using a conductive substrate cleaned by the cleaning apparatus of Embodiment 1, and FIG. 4 is a partially enlarged view of the electrophotographic photosensitive member of FIG. It is a schematic cross section.

<About the conductive substrate cleaning device>
The cleaning apparatus W according to the first embodiment includes the first to fourth cleaning tanks 11, 21, 31, 41 and the cleaning liquid in a predetermined cleaning tank among the first to fourth cleaning tanks 11, 21, 31, 41. So that the bubble supply section B for supplying bubbles made of a cleaning gas not containing oxygen and the conductive substrate S are sequentially immersed in the cleaning liquid in the first to fourth cleaning tanks 11, 21, 31, 41. And a substrate transfer unit 1 for transferring. In addition, in FIG. 1, the bubble supply part B is abbreviate | omitting illustration.

[Substrate transfer section]
The substrate transfer unit 1 includes a rail 3 provided on the first to fourth cleaning tanks 11, 21, 31, and 41, and a robot hand 2 provided to be movable along the rail 3.

[First cleaning tank]
The first cleaning tank 11 is filled with pure water or ion-exchanged water, preferably a pure water or ion-exchanged water cleaning solution 18 in which a surfactant is dissolved, and the cleaning solution 18 is filled with a predetermined temperature (for example, A heater 16 for heating to 40 to 60 ° C. is provided.
An ultrasonic oscillator 17 is provided at the bottom of the first cleaning tank 11 so that ultrasonic waves oscillate when the conductive substrate S is immersed in the cleaning liquid 18 in the first cleaning tank 11. ing.

A cleaning liquid 18 is steadily fed into the first cleaning tank 11 from a tank (not shown) through a pipe 12.
A pipe 19 having a pump 14 and a filter 15 is connected to the bottom of the first cleaning tank 11, and oil, dust, chips and the like removed from the surface of the conductive substrate S by cleaning are dispersed. The cleaning liquid 18 is circulated from the pipe 19 through the filter 15 by the pump 14, and dust, chips and the like are captured by the filter 15.
The cleaning liquid 18 overflows due to the immersion of the conductive substrate S, and the liquid that opens near the liquid surface is discharged from the pipe 13 to the outside, and the discharged cleaning liquid is processed by a drainage processing device (not shown).

  As the surfactant added to the cleaning liquid 18, a nonionic surfactant and / or an anionic surfactant that does not corrode the conductive substrate S can be used. Nonionic surfactants of oxyethylene alkylphenyl ether, polyoxyethylene / polyoxypropylene block copolymer type and nonylphenol polyoxyethylene ether, and sulfates, silicates, carbonates of alkylbenzene, higher alcohols, α-olefins, etc. Or the anionic surfactant of a phosphate is mentioned.

  Further, as a cleaning aid (builder), an inorganic builder such as sodium carbonate, sodium tripolyphosphate, potassium pyrophosphate, sodium silicate, or sodium sulfate, or an organic builder such as carboxymethyl cellulose, methyl cellulose, or organic amine is added to the cleaning liquid 18. Also good.

The concentration of the surfactant in the cleaning liquid 18 is 0.5 to 30%, preferably 4 to 15%.
The cleaning time (immersion time) in which the conductive substrate S is immersed in the cleaning liquid 18 for cleaning is 0.5 to 10 minutes, preferably 1.5 to 5 minutes.

[Second to third washing tanks]
The second cleaning tank 21, the third cleaning tank 31, and the fourth cleaning tank 41 are filled with pure water or ion-exchanged water as the cleaning liquids 25, 35, and 45, respectively. , 31 and 41, the rinsing process is performed in order. At this time, bubbles made of a cleaning gas not containing oxygen are supplied to the cleaning liquids 25, 35, 45 in the second to fourth cleaning tanks 21, 31, 41. The dissolved oxygen is kept low. The dissolved oxygen amount at this time is specifically suppressed to 2 mg / L or less, and the dissolved oxygen amount is preferably as low as possible.

The cleaning liquids 25, 35, 45 of the second to fourth cleaning tanks 21, 31, 41 are filtered from the pipes 26, 36, 46 provided at the bottom of each cleaning tank by the pumps 22, 32, 42. It circulates through and is supplemented with dust, chips, etc. by each filter.
The cleaning liquid 45 is supplied from the tank 60 to the fourth cleaning tank 41, the cleaning liquid 45 is supplied to the third cleaning tank 31 by the overflow from the fourth cleaning tank 41, and the third cleaning tank 31 is overflowed by the overflow from the third cleaning tank 31. The cleaning liquid 35 is supplied to the second cleaning tank 21, and the cleaning liquid 25 overflowing from the second cleaning tank 21 is discharged to the outside from a pipe 27 that opens near the liquid surface, and is processed by a drainage processing device (not shown). .

  In FIG. 1, reference numeral 50 denotes a clean booth, and the conductive substrate S that has completed the rinsing process in the fourth cleaning tank 41 is transferred to the clean booth 50 and the drying process is performed in the clean booth 50. .

[Bubble supply unit]
The bubble supply unit B supplies the bubble generator b1 with one or more gases selected from nitrogen, carbon dioxide, argon and helium as a cleaning gas not containing oxygen and the bubble generator b1. A supply source b2 for introducing the cleaning liquid in the cleaning tank into the bubble generator b1 and generating microbubbles in the cleaning liquid introduced into the bubble generator (microbubble generator) b1. It is comprised so that it may supply in the washing | cleaning liquid.
In the first embodiment, the case where microbubbles made of nitrogen gas are supplied into the cleaning liquids 25, 35, and 45 in the second to fourth cleaning tanks 21, 31, and 41 has been described. The bubble supply unit B is not shown.

  The bubble supply unit B corresponding to the second cleaning tank 21 will be described. The bubble generator b1 includes a first introduction port b11 for introducing the cleaning gas from the gas supply source b2 into the inside, and a second cleaning unit. It has a second introduction port b12 for introducing the cleaning liquid 25 in the tank 21 into the inside, and a delivery port b13 for sending the cleaning liquid having microbubbles into the second cleaning tank 21. The first inlet b11 is connected to the gas supply source b2 via a pipe b3 having a flow meter, and the second inlet b12 is connected to a pipe b4 having a sampling port in the cleaning liquid 25 in the second cleaning tank 21. The outlet b13 is connected to a pipe b5 having a discharge port in the cleaning liquid 25 in the second cleaning tank 21.

  Examples of the method for generating microbubbles by the bubble generator b1 include a swirling liquid flow method, a static mixer method, a pressurization method, a cavitation method, a venturi method, a pore method, a rotation method, and the like. It is not limited to. Specific examples include microbubble generators described in JP-A-2008-23435, JP-A-2003-126665, JP-A-6-165806, and the like.

  The bubble generator b1 is preferably one that generates bubbles including microbubbles having an area average diameter of 0.1 to 100 μm. That is, in the present invention, the bubbles made of the cleaning gas used in the rinsing treatment preferably mainly include macro bubbles having an area average diameter of 0.1 to 100 μm, and bubbles smaller than 0.1 μm and bubbles larger than 100 μm. May be included at a ratio (volume ratio) of less than half.

The bubble supply unit B individually corresponding to the third and fourth cleaning tanks 31 and 41 has the same configuration as the bubble supply unit B corresponding to the second cleaning tank 21.
The immersion time (rinsing time) of the conductive substrate S in the second to fourth cleaning tanks 21, 31, and 41 is 0.5 to 10 minutes, preferably 1.5 to 5.0 minutes, respectively.

In the present invention, the area average diameter of the bubbles employs a value obtained by sampling an aqueous cleaning liquid containing bubbles and measuring it with a laser diffraction scattering type particle size distribution measuring apparatus.
The area average diameter of the bubbles contained in the aqueous processing liquid is a value measured by a laser diffraction / scattering particle size measuring device (for example, Microtrac MT3000 manufactured by Nikkiso Co., Ltd.).

<About cleaning method of conductive substrate>
The method for cleaning a conductive substrate of the present invention includes a step of immersing the conductive substrate for an electrophotographic photosensitive member in an aqueous cleaning solution to which bubbles made of a cleaning gas not containing oxygen are supplied.
In the first embodiment, the cleaning device W described in FIGS. 1 and 2 is used, and the cleaning process (main cleaning process) in the first cleaning tank 11 and the second to fourth cleaning tanks 21, 31, 41 are used. The rinsing process and the drying process in the clean booth 50 are performed, and the rinsing process immerses the electroconductive substrate for the electrophotographic photosensitive member in an aqueous cleaning solution supplied with bubbles made of a cleaning gas not containing oxygen. Process.

[Washing process]
The cut conductive substrate 1 is supported in a suspended state by a robot hand 2 disposed on a rail 3 and is washed in a cleaning liquid 18 at a predetermined temperature containing a surfactant in the first cleaning tank 11 for a predetermined time. Soaked. During this time, ultrasonic waves are oscillated in the cleaning liquid 18 by the ultrasonic oscillator 17. During this time, the conductive substrate S may be swung as necessary. By this cleaning process, oil, dust, chips and the like attached to the surface of the conductive substrate S are removed. The temperature of the cleaning liquid 18 can be about 40 to 50 ° C., and the immersion time can be about 0.5 to 10 minutes, but is not limited to this.

[Rinsing process]
When the cleaning process in the first cleaning tank 11 is completed, the conductive substrate S is then immersed in the cleaning liquid 25 in the second cleaning tank 21 for a predetermined time, and the first rinsing process is performed. During this time, bubbles containing microbubbles having an area average diameter of 0.1 to 100 μm are supplied into the cleaning liquid 25 by the bubble supply unit B corresponding to the second cleaning tank 21. Moreover, as immersion time, it can be set as about 0.5-10 minutes, However, It is not limited to this.

  After the first rinsing process in the second cleaning tank 21, the second and third rinsing processes in the third and fourth cleaning tanks 31 and 41 are performed in the same manner. Note that the conductive substrate S may be swung by the robot hand 2 as necessary during the first to third rinsing processes. For example, in the case of a cylindrical shape, the conductive substrate S may be swung.

  According to the present invention, the conductive substrate S having a highly cleaned surface can be obtained through the washing step and the rinsing step. Then, according to the electrophotographic photosensitive member manufactured by providing a photosensitive layer on the conductive substrate S, it is possible to remove foreign matter (transparent foreign matter, fibrous dust, chips, etc.) or oil on the conductive substrate S. The resulting image quality defect does not occur, and it is possible to maintain excellent image quality over a long period of time.

  In the present invention, it is considered that the microbubbles contained in the aqueous cleaning liquid can stay in the liquid for a long time due to its size and are in a charged state having polarity. Thereby, it is considered that the foreign substance and oil content on the conductive substrate S and the foreign substance and oil component floating in the liquid are surely brought into contact with the foreign substance and the oil component and floated. That is, in the rinsing process after the cleaning process, foreign substances and oil are removed from the conductive substrate S very effectively and recontamination to the conductive substrate S is sufficiently prevented. It is considered that the conductive substrate S is obtained.

In addition, since the microbubbles having an area average diameter of 0.1 to 100 μm can enter even the minute uneven portions of the conductive substrate S, this also contributes to the achievement of advanced cleaning. Conceivable. In the present invention, microbubbles having an area average diameter of 20 to 90 μm are preferable, and microbubbles of 30 to 60 μm are more preferable.
Furthermore, since the microbubble is made of a gas not containing oxygen, the amount of dissolved oxygen in the aqueous cleaning liquid is reduced, and the activation of microorganisms due to the increase in the amount of dissolved oxygen is not caused. As a result, discharge of transparent foreign matters from the microorganisms into the aqueous cleaning liquid is suppressed, and adhesion of transparent foreign matters to the conductive substrate S is suppressed.

  Note that when the area average diameter of the bubbles contained in the aqueous cleaning liquid is less than 0.1 μm, it is difficult to highly clean the conductive substrate S. The reason for this may be that bubbles having an area average diameter of less than 0.1 μm have insufficient buoyancy and are easily dissolved in the liquid, so that the effect of removing foreign matter and oil cannot be sufficiently obtained.

  On the other hand, even when the area average diameter of the bubbles contained in the aqueous cleaning liquid exceeds 100 μm, it tends to be difficult to highly clean the conductive substrate S. The reason for this is that bubbles with an area average diameter of more than 100 μm generated by air blowing into the liquid repel foreign matter and oil from the conductive substrate S due to the pressure effect of the air, so that the foreign matter and oil again become conductive substrate S. This is considered to be because the possibility of adhering to the surface increases. Further, in the case of bubbles having an area average diameter of more than 100 μm, the residence time in the liquid is short, and it is not possible to enter even the minute irregularities on the surface of the conductive substrate S. It is considered that fine foreign matter and oil present in the water cannot be completely removed.

  The amount of microbubbles supplied to the cleaning liquid in the cleaning tank is such that the conductive substrate S is completely covered with the microbubbles. For example, when rinsing is performed by immersing 20 conductive substrates S in a cleaning liquid in a cleaning tank having a volume of 250 L, the air flow rate of microbubbles from the bubble generator b1 to the cleaning tank is, for example, 0. It is about 25-0.75 L / min, Preferably it is 0.35-0.65 L / min.

[Drying process]
The conductive substrate S after the rinsing step is dried by spraying clean air at 80 ° C. in a known method, for example, in a clean booth 50 maintained at a cleanness of 100.

<Configuration of electrophotographic photoreceptor>
3 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member using a conductive substrate cleaned by the cleaning apparatus of Embodiment 1, and FIG. 4 is a partially enlarged schematic cross-sectional view of the electrophotographic photosensitive member of FIG. FIG.
In the present invention, the electrophotographic photosensitive member P includes the conductive substrate S cleaned as described above, and the photosensitive layer Pb provided on the outer peripheral surface of the conductive substrate S.

  The photosensitive layer Pb is functionally separated into a single-layer type photosensitive layer containing a charge transport material and a charge generation material in the same layer, a charge generation layer containing a charge generation material, and a charge transport layer containing a charge transport material. And a laminated type photosensitive layer. Further, the charge generation layer may have a stacked structure, and the charge transport layer may have a stacked structure. Further, for the purpose of improving the adhesion between the conductive substrate S and the photosensitive layer Pb, an intermediate layer may be formed on the conductive substrate Pb, and the photosensitive layer may be formed on the intermediate layer. Further, for the purpose of improving the durability of the photoreceptor, a protective layer may be formed on the photosensitive layer.

As shown in FIGS. 3 and 4, the photoreceptor P according to the present embodiment has an intermediate layer Pa formed on the outer peripheral surface of a cylindrical conductive substrate S, and a photosensitive layer Pb formed on the intermediate layer Pa. It is the composition which becomes.
Further, the photoreceptor P includes a charge generation layer Pb _{1 in} which the photosensitive layer Pb contains a charge generation material, and a charge transport layer containing a charge transport material that is laminated on the charge generation layer Pb _1. This is a laminated photoconductor that is functionally separated into Pb ₂ . In this embodiment, no protective layer is provided, and the charge transport layer Pb ₂ is a surface layer.
Hereinafter, the respective layers constituting the photoreceptor P according to the present embodiment will be described with reference to FIGS. 3 and 4.

[Conductive substrate]
The conductive substrate S functions as an electrode of the photoreceptor P and also functions as a support member for the layers sequentially stacked on the conductive substrate S, that is, the intermediate layer Pa and the photosensitive layer Pb.
Examples of the conductive material constituting the conductive base 2 include aluminum, copper, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum, and other conductive metals, aluminum alloys, brass, and the like. Conductive alloys such as copper alloys and zinc alloys, and conductive metal compounds such as tin oxide and indium oxide can be used.

  Further, as the conductive material constituting the conductive substrate S, a polythioferene-based, polyacetylene-based, polyaniline-based, or polypyrrole-based conductive polymer may be used. Furthermore, as the conductive material constituting the conductive substrate S, a polymer material such as polyethylene terephthalate, nylon, polyester, polyoxymethylene or polystyrene, the surface of hard paper or glass is made of the conductive metal or conductive alloy. It is also possible to use a laminate of selected metal foils, or one obtained by depositing or applying the conductive compound or conductive polymer.

The shape of the conductive substrate S is not limited to the cylindrical shape as shown in FIG. 3, and may be a predetermined shape such as a sheet shape according to the desired shape of the photoreceptor P.
Further, the surface of the conductive substrate S may be subjected to an anodized film treatment, a surface treatment with chemicals or hot water, a coloring treatment, or a surface roughening as necessary within a range that does not affect the image quality. An irregular reflection process may be performed.
The surface of the conductive substrate S is subjected to the treatment as described above, so that the laser beam from the exposure light source and the laser reflected inside the photosensitive layer Pb are generated in the case of an electrophotographic process using a laser as the exposure light source. Image defects due to light interference can be prevented.
The present invention is an invention relating to such cleaning of the conductive substrate S.

[Middle layer]
The intermediate layer Pa is a layer laminated on the outer peripheral surface of the conductive substrate S. As the intermediate layer Pa, a resin layer or an alumite layer made of various resin materials is used.
As the resin material constituting the resin layer, polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, melamine resin, silicone resin, polyvinyl butyral resin, Resins such as polyvinylpyrrolidone resins, polyacrylamide resins and polyamide resins, or copolymer resins containing two or more of the repeating units constituting these resins; and casein, gelatin, polyvinyl alcohol, cellulose, nitrocellulose, and Examples include ethyl cellulose.

  Among the resin materials constituting these resin layers, alcohol-soluble nylon resins and polyamide resins are preferably used, and alcohol-soluble nylon resins are particularly preferable. Preferred alcohol-soluble nylon resins include, for example, so-called copolymer nylon obtained by copolymerizing 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 2-nylon and 12-nylon, and N- Examples thereof include resins obtained by chemically modifying nylon such as alkoxymethyl-modified nylon and N-alkoxyethyl-modified nylon.

  In addition, filler particles may be added to the intermediate layer Pa for the purpose of providing a charge adjusting function. Examples of the filler particles include carbon fine particles such as carbon nanocoils, metal oxide fine particles such as titanium oxide, aluminum oxide, and lead oxide, metal hydroxide particles such as aluminum hydroxide, and the like. The particle diameter of the filler particles is suitably about 0.01 μm or more and 0.3 μm or less. Preferably, it is about 0.02 μm or more and 0.1 μm or less.

  The intermediate layer Pa is formed, for example, by applying an intermediate layer coating solution prepared by dissolving or dispersing the resin material in an appropriate solvent to the surface of the conductive substrate S. When the filler particles are included in the intermediate layer Pa, for example, a coating solution for the intermediate layer is prepared by dispersing carbon nanocoils in a resin solution obtained by dissolving a resin material in an appropriate solvent. The intermediate layer Pa can be formed by applying the liquid to the surface of the conductive substrate S.

  As the solvent for the coating solution for the intermediate layer, water, various organic solvents, or a mixed solvent thereof is used. For example, water, methanol, ethanol or butanol alone, or water and alcohols, two or more alcohols. A mixed solution, a mixed solvent such as acetone or dioxolane and alcohols, a halogen-based organic solvent such as dichloroethane, chloroform or trichloroethane, and alcohols is used. Among these solvents, non-halogen organic solvents are preferably used in consideration of the global environment.

As a method for dispersing the filler particles in the resin solution, a general method using a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser, a paint shaker, or the like can be used. In addition, by using a media-less type dispersion device that uses a very strong shearing force generated by passing a solvent containing filler particles in a microscopic space at an ultra-high pressure, a more stable coating solution for intermediate layers can be obtained. It can be manufactured.
As a coating method for the intermediate layer coating solution, a conventionally known coating method is selected, and examples thereof include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and a dip coating method.

By providing the intermediate layer Pa, injection of charges from the conductive substrate S to the photosensitive layer Pb can be prevented. Therefore, it is possible to prevent a decrease in chargeability of the photosensitive layer Pb, to suppress a decrease in surface charge other than a portion to be erased by exposure, and to prevent occurrence of defects such as fogging on the image.
Further, by providing the intermediate layer Pa, the surface of the conductive substrate S can be covered to obtain a uniform surface, so that the film formability of the photosensitive layer Pb can be improved and the conductive substrate S can be formed. It is possible to suppress peeling of the photosensitive layer Pb and improve adhesion.

The thickness of the intermediate layer Pa is preferably 0.01 μm or more and 20 μm or less, and more preferably 0.05 μm or more and 10 μm or less. If the thickness of the intermediate layer Pa is less than 0.01 μm, the unevenness of the conductive substrate S cannot be covered to obtain a uniform surface property, and charge injection from the conductive substrate S to the photosensitive layer Pb is not possible. Cannot be prevented, and the chargeability of the photosensitive layer Pb is lowered. That is, it cannot substantially function as the intermediate layer Pa.
Further, making the thickness of the intermediate layer Pa larger than 20 μm makes it difficult to form the intermediate layer Pa when the intermediate layer Pa is formed by a dip coating method, and the photosensitive layer Pb is formed on the intermediate layer Pa. Since it cannot form uniformly and the sensitivity of the obtained photoreceptor P falls, it is not preferable.

  In the photoreceptor P according to this embodiment, the intermediate layer Pa is provided between the conductive substrate S and the photosensitive layer Pb. However, it is not always necessary to provide the intermediate layer Pa. However, if there is no intermediate layer Pa between the conductive substrate S and the photosensitive layer Pb, the chargeability in a minute region is reduced due to defects in the conductive substrate S or the photosensitive layer Pb, black spots, etc. Therefore, the intermediate layer Pa is preferably provided.

[Charge generation layer]
The charge generation layer Pb ₁ is a layer formed on the intermediate layer Pa. The charge generation layer Pb ₁ contains, as a main component, a charge generation material that generates charges by absorbing light. Examples of the charge generation material contained in the charge generation layer Pb ₁ include an organic photoconductive material containing an organic pigment and an inorganic photoconductive material containing an inorganic pigment.

Examples of organic photoconductive materials including organic pigments include monoazo pigments, azo pigments such as bisazo pigments and trisazo pigments, indigo pigments such as indigo and thioindigo, and perylenes such as peryleneimide and perylene anhydride. Organic photoconductive materials such as pigments, polycyclic quinone pigments such as anthraquinone and pyrenequinone, metal phthalocyanines such as titanyl phthalocyanine and phthalocyanine pigments such as metal-free phthalocyanine, squarylium dyes, pyrylium salts and thiopyrylium salts, and triphenylmethane dyes Is mentioned.
Examples of inorganic photoconductive materials containing inorganic pigments include selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, amorphous silicon, and other inorganic photoconductors.

  In addition, the charge generation materials include triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue, erythrosine, rhodamine B, rhodamine 3R, acridine dyes typified by acridine orange and frapeosin, and methylene blue. And thiazine dyes typified by methylene green, oxazine dyes typified by capri blue and meldra blue, cyanine dyes, styryl dyes, pyrylium salt dyes or thiopyrylium salt dyes, etc. Good.

The method for forming the charge generation layer Pb ₁ is selected from conventionally known formation methods. The method for vacuum-depositing the charge generation material on the surface of the conductive substrate S or the intermediate layer Pa, or the charge generation material using a suitable solvent. For example, a method of coating the surface of the intermediate layer Pa with a coating solution for a charge generation layer obtained by dispersing in the medium is used. Among them, a charge generating layer coating solution was prepared by dispersing the charge generating material in a binder resin solution obtained by mixing a binder resin as a binder in a solvent by a conventionally known method. A method of applying the charge generation layer coating solution to the surface of the intermediate layer Pa is preferably used.

Examples of the binder resin used for the charge generation layer Pb ₁ include polyester resin, polystyrene resin, polyurethane resin, phenol resin, alkyd resin, melamine resin, epoxy resin, silicone resin, acrylic resin, methacrylic resin, polycarbonate resin, and polyarylate. Resin, phenoxy resin, petital resin, polyvinyl butyral resin, polyvinyl chloride resin, polyvinyl formal resin, and other resins, and copolymer resins containing two or more of the repeating units constituting these resins. it can.

Specific examples of the copolymer resin include insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and acrylonitrile-styrene copolymer resin. be able to.
The binder resin is not limited to these, and a commonly used resin can be used as the binder resin. One kind of these resins may be used alone, or two or more kinds thereof may be mixed and used.

  Examples of the solvent for the charge generation layer coating solution include halogenated hydrocarbons such as dichloromethane or dichloroethane, alcohols such as methanol and ethanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and esters such as ethyl acetate and butyl acetate. , Ethers such as tetrahydrofuran or dioxane, alkyl ethers of ethylene glycol such as 1,2-dimethoxyethane, aromatic hydrocarbons such as benzene, toluene or xylene, or N, N-dimethylformamide or N, N-dimethyl An aprotic polar solvent such as acetamide is used, and one kind may be used alone, or two or more kinds may be used as a mixed solvent. Among these, non-halogen organic solvents are preferably used in consideration of the global environment.

In the charge generation layer Pb ₁ including the charge generation material and the binder resin, the weight ratio of the weight of the charge generation material to the weight of the binder resin is preferably 10/100 or more and 400/100 or less.
When the weight ratio of the weight of the charge generating material to the weight of the binder resin is less than 10/100, the sensitivity of the photoreceptor 1 is lowered. On the other hand, when the weight ratio of the weight of the charge generating material to the weight of the binder resin exceeds 400/100, not only the film strength of the charge generating layer Pb ₁ is lowered but also the dispersibility of the charge generating material is lowered and coarse. Since the particles increase, the surface charge other than the portion to be erased by exposure decreases, and the image defect, particularly the fogging of an image called a black spot where a toner adheres to a white background and a minute black spot is formed increases.

The charge generation material may be pulverized in advance by a pulverizer before being dispersed in the binder resin solution. Examples of the pulverizer used for the pulverization treatment include a ball mill, a sand mill, an attritor, a vibration mill, and an ultrasonic disperser.
Examples of the disperser used when dispersing the charge generating material in the binder resin solution include a paint shaker, a ball mill, and a sand mill. As a dispersion condition, an appropriate condition is selected so that impurities are not mixed due to wear of a container used and a member constituting the disperser.

As a coating method for the charge generation layer coating solution, a conventionally known coating method is selected in the same manner as the coating method for the intermediate layer coating solution. For example, a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and the like. And dip coating method.
The film thickness of the charge generation layer Pb ₁ is preferably 0.05 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 1 μm or less. If the film thickness of the charge generation layer Pb ₁ is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity of the obtained photoreceptor P is lowered. On the other hand, when the film thickness of the charge generation layer Pb ₁ exceeds 5 μm, charge transfer inside the charge generation layer Pb ₁ becomes a rate-limiting step in the process of erasing the surface charge of the photosensitive layer Pb, and the sensitivity of the resulting photoreceptor P Decreases.

[Charge transport layer]
The charge transport layer Pb ₂ is provided on the charge generation layer Pb _1, mainly composed of a charge transport material capable of transporting accept the charges generated by the charge generation material contained in the charge generation layer Pb _1, binder It contains a resin and, if necessary, known additives. Here, the main component means that the component contains an amount capable of expressing its main function.

As the charge transport material, hole transport materials and electron transport materials used in the technical field can be used.
Examples of hole transport materials include carbazole derivatives, pyrene derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazones. Compound, polycyclic aromatic compound, indole derivative, pyrazoline derivative, oxazolone derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, triarylamine derivative, triarylmethane derivative, phenylenediamine derivative Stilbene derivatives, enamine derivatives and benzidine derivatives, and groups derived from these compounds in the main chain. The polymer having the side chain, such as poly -N- vinylcarbazole, poly-1-vinylpyrene, ethylcarbazole - formaldehyde resins, triphenylmethane polymers, such as poly-9-vinyl anthracene, and polysilane, and the like.

Examples of the electron transporting material include organic compounds such as benzoquinone derivatives, tetracyanoethylene derivatives, tetracyanoquinodimethane derivatives, fluorenone derivatives, xanthone derivatives, phenanthraquinone derivatives, phthalic anhydride derivatives, and diphenoquinone derivatives.
These charge transport materials can be used alone or in combination of two or more.

The binder resin is not particularly limited, and any resin known in the art can be used. In particular, a resin containing polycarbonate as a main component is preferable from the viewpoint of film strength.
Examples of the resin other than polycarbonate include vinyl polymer resins such as polymethyl methacrylate resin, polystyrene resin, and polyvinyl chloride resin, and copolymer resins including two or more of repeating units constituting these, and polyester resins Polyester carbonate resin, polysulfone resin, phenoxy resin, epoxy resin, silicone resin, polyarylate resin, polyamide resin, methacrylic resin, acrylic resin, polyether resin, polyurethane resin, polyacrylamide resin, phenol resin, polyphenylene oxide resin and these A thermosetting resin obtained by partially crosslinking the resin can be used. These resins can be used alone or in combination of two or more.

The ratio W3 / W4 between the weight W3 of the charge transport material and the weight W4 of the binder resin is preferably 30/100 (30/100) or more and 200/100 or less (200/100).
When the ratio W3 / W4 exceeds 200/100, the film strength is remarkably lowered and image defects may occur.
On the other hand, when the ratio W3 / W4 is less than 30/100, the viscosity of the coating solution increases, the coating speed decreases, and the productivity may be remarkably deteriorated.

The charge transport layer Pb ₂ may contain a known additive exemplified as the additive of the charge generation layer Pb ₁ as long as the effects of the present invention are not inhibited.
For example, the content of the antioxidant is preferably 0.1 to 50 parts by weight per 100 parts by weight of the charge transport material.
If the content of the antioxidant is less than 0.1 parts by weight, it may not be possible to obtain a sufficient effect for improving the stability of the coating solution and improving the durability of the photoreceptor P. On the other hand, if the content of the antioxidant exceeds 50 parts by weight, the photoreceptor characteristics may be adversely affected.

Similarly to the charge generation layer Pb ₁ , the charge transport layer Pb ₂ is, for example, a charge transport layer coating solution prepared by dissolving or dispersing a charge transport material, a binder resin, and a known additive in an organic solvent in an appropriate solvent. The coating solution is applied onto the charge generation layer Pb ₁ and then dried to remove the organic solvent.
The other processes and conditions are in accordance with the formation of the charge generation layer Pb ₁ .

  Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, xylene and monochlorobenzene, halogenated hydrocarbons such as dichloromethane and dichloroethane, ethers such as tetrahydrofuran, dioxane and dimethoxymethyl ether, and N, N-dimethyl. Examples include aprotic polar solvents such as formamide. These solvents can be used alone or in combination of two or more. One of these solvents may be used alone, or two or more thereof may be mixed and used. Further, if necessary, a solvent such as alcohols, acetonitrile or methyl ethyl ketone can be further added to the above solvent. Among these solvents, non-halogen organic solvents are preferably used in consideration of the global environment.

The charge transport layer Pb ₂ may contain organic fine particles and inorganic fine particles (also referred to as “filler”) in order to improve the wear resistance of the coating film.
The content of the filler is 1 to 10% by weight of the charge transport layer Pb _2, preferably 1 to 5 wt%.
The thickness of the charge transport layer Pb ₂ is not particularly limited, but is preferably 5 to 40 μm, and more preferably 10 to 30 μm. If the thickness of the charge transport layer Pb ₂ is less than 5 μm, the charge retention ability may be lowered. On the other hand, if the thickness of the charge transport layer Pb ₂ exceeds 40 μm, the resolution of the photoreceptor P may be lowered.

[Image forming apparatus]
Next, an image forming apparatus including the electrophotographic photosensitive member P having the conductive substrate S cleaned by the cleaning apparatus and the cleaning method of Embodiment 1 will be described.
FIG. 5 is a schematic view showing an example of an image forming apparatus provided with the electrophotographic photosensitive member of FIG.
The image forming apparatus 110 includes a charger 111, an exposure unit 112, a developing unit 113, a transfer unit 114, and a separator 115 around the electrophotographic photosensitive member P in this order along the rotation direction R of the electrophotographic photosensitive member P. A cleaner 116 and a static eliminator 117 are disposed. The electrophotographic photosensitive member P, the charger 111, the developing device 113, the separator 115, the cleaner 116, and the static eliminator 117 are accommodated in a housing 118.
Further, the image forming apparatus 110 includes a fixing device 119 in the conveyance direction M of the transfer paper 127 that is a recording medium.

The charger 111 is, for example, a charger charger, and uniformly charges the surface of the photosensitive member P with electric power supplied from the external power source 120A.
The exposure device 112 is constituted by a semiconductor laser or the like, and exposes the surface of the photoreceptor P with a laser beam from the semiconductor laser to form an electrostatic latent image.
The developing device 113 supplies toner (developer) to develop the electrostatic latent image on the surface of the photoreceptor P formed by the exposure of the exposure device 112. The developing device 113 includes a developing roller 122 in the casing 121, and supplies the toner stirred in the casing 121 by the developing roller 122 to the surface of the photoreceptor P. In this case, the toner may be a one-component system or a two-component system including a carrier.

The transfer device 114 is provided so as to come into contact with the photoreceptor P via the transfer paper 127. The transfer device 114 is supplied with a voltage from the external power source 120 </ b> B, and transfers the toner image formed on the surface of the photoreceptor P onto the transfer paper 127.
The separator 115 is provided for peeling the transfer paper 127 from the surface of the photoreceptor P.
The cleaner 116 is provided to collect the toner remaining on the surface of the photoreceptor P. The cleaner 116 scrapes off the residual toner adhering to the surface of the photoreceptor P by the cleaning blade 123 and collects it in the recovery casing 124.
The neutralizer 117 neutralizes the surface of the photoreceptor P from which the residual toner has been removed.
The fixing device 119 conveys the transfer paper 127 having the toner image transferred by the transfer device 114 between the heating roller 125 and the pressure roller 126, melts the toner image, and heat-presses the transfer paper 127 on the transfer paper 127. Let it settle.

The electrophotographic process by the image forming apparatus 110 having the above-described configuration is performed as follows.
That is, when the image forming apparatus 110 is requested to form an image based on predetermined image data, the charger 111 uniformly charges the surface of the photoreceptor P to a predetermined potential. Next, a laser beam emitted from the exposure device 112 exposes the surface of the photoconductor P based on the image data, whereby an electrostatic latent image based on the image data is formed on the surface of the photoconductor P. The electrostatic latent image is successively visualized by a developing device 113 provided downstream of the exposure device 112 with respect to the rotation direction R of the photoconductor P, and a toner image is formed on the surface of the photoconductor P. The

  In synchronization with the exposure of the surface of the photoreceptor P, the transfer paper 127 moves in the direction of the arrow P and is conveyed between the photoreceptor P and the transfer device 114. Thus, the toner image formed on the surface of the photoconductor P is sequentially transferred onto the transfer paper 127 as the photoconductor P rotates and the transfer paper 127 is conveyed. Subsequently, the transfer paper 127 onto which the toner image has been transferred is conveyed to a fixing device 119, where the toner image is fixed on the transfer paper 127 and then discharged to the outside of the image forming apparatus 110.

  On the other hand, after the toner image is transferred, the toner remaining on the surface of the photoreceptor P is removed by the cleaning blade 123 scraping off the toner as the photoreceptor P rotates. Thereafter, the surface of the photoconductor P is further neutralized by the static eliminator 117 by rotating the photoconductor P, and the above-described electrophotographic process is repeated to form an image on the transfer paper 127.

According to this image forming apparatus 110, even under low-potential development conditions, it occurred in the photosensitive layer Pb of the photoreceptor P after the exposure by the exposure device 112 and before the development processing by the development device 113 was started. The charges can quickly move to the surface of the photoreceptor P to cancel the surface charges. Therefore, an image having a good image density can be formed on the transfer paper 127 by the image forming process.
As described above, since the conductive substrate cleaned by the cleaning apparatus and the cleaning method of the present invention is highly cleaned, the electrophotographic photoreceptor manufactured using the conductive substrate after the cleaning process is Image quality defects due to foreign matter on the conductive substrate do not occur, and excellent image quality can be maintained over a long period of time.

In the conductive substrate cleaning apparatus and cleaning method of the present invention, the surface of the conductive substrate S may be roughened.
In particular, in an image forming apparatus using laser beam light, the surface of the conductive substrate S is usually roughened in order to prevent interference fringes due to laser light. The surface of such a conductive substrate S is more difficult to clean due to the unevenness formed by the roughening treatment. For this reason, the occurrence of spot defects due to the abrasive particles used for roughening and the fragments thereof remaining on the conductive substrate S is a serious problem.
According to the present invention, even such a roughened conductive substrate S can be cleaned to a sufficiently high degree, so that it has high quality suitable for applications such as an image forming apparatus using laser beam light. The electrophotographic photosensitive member P can be efficiently produced.

(Embodiment 2)
In the conductive substrate cleaning apparatus and cleaning method of the second embodiment, at least one cleaning tank out of the second to fourth cleaning tanks 21, 31, 41 used in the rinsing process shown in FIG. In the cleaning liquid in which the sound wave generator 17 (see FIG. 1) is provided and at least one of the three rinsing processes is supplied with bubbles of cleaning gas not containing oxygen and oscillating ultrasonic vibrations Then, the conductive substrate is rinsed.
In the second embodiment, other configurations are the same as those in the first embodiment.

(Embodiment 3)
In the conductive substrate cleaning apparatus and cleaning method of Embodiment 3, the cleaning gas containing no surfactant is contained in the cleaning liquid 18 containing the surfactant in the first cleaning tank 11 used in the cleaning step shown in FIG. Air bubbles consisting of are supplied. Therefore, the conductive substrate is subjected to a cleaning process (main cleaning) in the cleaning liquid 18 in which bubbles made of a cleaning gas not containing oxygen are supplied and ultrasonic vibration is oscillated. In this case, the bubbles are preferably microbubbles having an area average diameter of 0.1 to 100 μm.
In the third embodiment, other configurations are the same as those in the first embodiment.

(Embodiment 4)
In the conductive substrate cleaning apparatus and cleaning method of the fourth embodiment, the cleaning liquids 25, 35, 45 contained in the second to fourth cleaning tanks 21, 31, 41 used in the rinsing process shown in FIG. Bubbles of different sizes are supplied inside. For example, microbubbles having an area average diameter of about 0.1 to 1 μm are supplied into the cleaning liquid 25 in the first cleaning tank 21, and about 1 to 10 μm in the cleaning liquid 35 in the second cleaning tank 31. Microbubbles are supplied, and about 10 to 100 μm of microbubbles are supplied into the cleaning liquid 45 in the third cleaning tank 41. Note that the size of the microbubbles may be decreased in the order of the second to fourth cleaning tanks 21, 31, and 41, or may be random.
In the fourth embodiment, other configurations are the same as those in the first embodiment.

(Embodiment 5)
In the conductive substrate cleaning apparatus and cleaning method of the fifth embodiment, the cleaning liquids 25, 35, 45 contained in the second to fourth cleaning tanks 21, 31, 41 used in the rinsing step shown in FIG. Bubbles made of different gases are supplied inside. For example, microbubbles made of nitrogen gas are supplied into the cleaning liquid 25 in the first cleaning tank 21, and microbubbles made of carbon dioxide gas are supplied into the cleaning liquid 35 in the second cleaning tank 31. Microbubbles made of argon gas are supplied into the cleaning liquid 45 in the third cleaning tank 41. In addition, you may make it supply the microbubble which consists of mixed gas to one or more among the 2nd-4th washing tanks 21, 31, and 41. FIG.
In the fourth embodiment, other configurations are the same as those in the first embodiment.

(Embodiment 6)
In the cleaning apparatus and cleaning method for the conductive substrate of Embodiment 6, bubbles made of a cleaning gas not containing oxygen are supplied to a cleaning solution that does not contain a surfactant, and the conductive substrate is immersed in the cleaning solution. Wash. For example, instead of using the first cleaning tank 11 shown in FIG. 1, cleaning is performed only by one or more rinsing processes using at least one of the second to fourth cleaning tanks.
In the sixth embodiment, other configurations are the same as those in the first embodiment.

Note that a preferable aspect of the present invention includes a combination of any of the plurality of aspects described above.
In addition to the embodiments described above, there can be various modifications of the present invention. These modifications should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the scope of the claims and all modifications within the scope.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
Microbubbles made of nitrogen gas generated by a microbubble generator (MBL11-102V-S: manufactured by Kansai Autome Equipment Co., Ltd.) are placed in a cleaning solution that does not contain a surfactant contained in a cleaning tank of a precision cleaning processing apparatus. It was supplied in the evening to replace oxygen dissolved in the cleaning solution with nitrogen. Note that pure water (manufactured by Organo) was used as the cleaning liquid.
After cleaning a cylindrical aluminum conductive substrate having a diameter of 30 mm, a length of 357 mm, and a thickness of 0.75 mm with a cleaning liquid containing a surfactant, the area average diameter is 35 in the cleaning liquid in the cleaning tank. Cleaning was performed by immersing microbubbles composed of nitrogen gas of ˜55 μm in a cleaning solution supplied at an air flow rate of 500 ml / min for 150 seconds. At this time, one conductive substrate was completely immersed in a cleaning liquid in a cleaning tank having a volume of 250 L, and the conductive substrate was completely covered with microbubbles. Moreover, it was 1.5 mg / L when the amount of dissolved oxygen in the washing | cleaning liquid at this time was measured.
And after washing | cleaning, the electroconductive base | substrate was dried in the clean booth.

  Next, 60 g of titanium oxide (Tybaked TTO-M-1: manufactured by Ishihara Sangyo Co., Ltd.), 60 g of alcohol-soluble nylon resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) and 1200 g of methanol are added to 800 g of 1,3-dioxolane, and a paint shaker is added. The coating solution for intermediate | middle layer was prepared by carrying out dispersion processing for 10 hours.

The obtained intermediate layer coating solution was applied to the outer peripheral surface of the conductive substrate by a dip coating method and naturally dried to form an intermediate layer having a thickness of 0.9 μm.
Next, 10 g of butyral resin (ESLEC BM-2: manufactured by Sekisui Chemical Co., Ltd.) and 15 g of titanyl phthalocyanine represented by the following structural formula (1) as a charge generating substance are added to 1400 g of 1,3-dioxolane, and dispersed in a ball mill for 72 hours. It processed and the coating liquid for charge generation layers was prepared.

The obtained charge generation layer coating solution was applied onto the intermediate layer by a dip coating method, and then naturally dried to form a charge generation layer having a thickness of 0.2 μm.
Next, 140 g of a polycarbonate resin (Z-400), 100 g of a butadiene compound represented by the following structural formula (2) as a charge transport material, and 5 g of an antioxidant (Irganox 1010) are dissolved in 1600 g of tetrahydrofuran, and applied to a charge transport layer. A liquid was prepared.

  The resulting charge transport layer coating solution was applied onto the charge generation layer by a dip coating method, and the resulting coating film was dried at 130 ° C. for 1 hour to form a charge transport layer having a thickness of 24 μm. The photoreceptor P of Example 1 shown in FIG.

(Example 2)
An electrophotographic photosensitive member of Example 2 was produced in the same manner as in Example 1 except that carbon dioxide was used as the microbubble in the cleaning treatment of the conductive substrate. The flow rate of microbubbles was set to 250 ml / min, and the amount of dissolved oxygen in the cleaning liquid at the time of cleaning was measured and found to be 1.2 mg / L.

(Example 3)
An electrophotographic photosensitive member of Example 3 was produced in the same manner as in Example 1 except that argon was used as the gas used for the microbubbles in the cleaning treatment of the conductive substrate. The flow rate of microbubbles was set to 500 ml / min, and the amount of dissolved oxygen in the cleaning liquid at the time of cleaning was measured and found to be 1.9 mg / L.

Example 4
An electrophotographic photoreceptor of Example 4 was produced in the same manner as in Example 1 except that helium was used as the gas used for the microbubbles in the cleaning treatment of the conductive substrate. The flow rate of microbubbles was set to 500 ml / min, and the amount of dissolved oxygen in the cleaning liquid at the time of cleaning was measured and found to be 1.9 mg / L.

(Comparative Example 1)
An electrophotographic photoreceptor of Comparative Example 1 was produced in the same manner as in Example 1 except that the gas used for the microbubbles in the cleaning treatment of the conductive substrate was air. The flow rate of microbubbles was set to 500 ml / min, and the amount of dissolved oxygen in the cleaning liquid at the time of cleaning was measured to be 6.0 mg / L.

(Comparative Example 2)
An electrophotographic photosensitive member of Comparative Example 2 was produced in the same manner as in Example 1 except that the microbubbles in the cleaning treatment of the conductive substrate were several millimeters. In this case, nitrogen bubbles were generated at a flow rate of 500 ml / min with a commercially available air tonetone, and the amount of dissolved oxygen in the cleaning liquid at the time of cleaning was measured to be 3.5 mg / L.

<Electrical characteristics>
Evaluation of electrical characteristics of the electrophotographic photoreceptors of Examples 1 to 4 and Comparative Examples 1 to 2 will be described below.
The electrophotographic photosensitive member of Example 1 was mounted on a test copying machine in which a digital copying machine (trade name: MX-4500, manufactured by Sharp Corporation) was modified. Then, a surface potential meter (manufactured by TREK JAPAN, mode 1344) was provided so that the surface potential of each electrophotographic photosensitive member in the electrophotographic process could be measured. A laser light source having a wavelength of 780 mm was used as a light source for exposing each electrophotographic photosensitive member.
Then, using the above-described test copying machine, after the initial (before printing) surface potential VL and 100,000 sheets of continuous printing in the electrophotographic photosensitive member of Example 1 in an environment of normal temperature / normal humidity (N / N). The surface potential VL of was measured. In addition, N / N environment here refers to 25 degreeC and 50% RH (relative humidity). The surface potential VL indicates the surface potential of the electrophotographic photosensitive member at the black background during exposure (refers to the surface potential of the electrophotographic photosensitive member at the developing portion).

Next, for each electrophotographic photosensitive member of Example 1, the difference ΔVL between the initial surface potential and the surface potential of the electrophotographic photosensitive member after continuous printing of 100,000 sheets was calculated, and the electrical characteristics were evaluated according to the following criteria. .
A: Good (ΔVL = 0 or more and less than 10).
B: No problem in actual use (ΔVL = 10 or more and less than 20).
C: A practically usable level (ΔVL = 20 or more and less than 35).
D: Actual use is not possible (ΔVL = 35 or more).

<Image quality>
Next, image quality evaluation was performed on Example 1. Specifically, the electrophotographic photosensitive member of Example 1 is mounted on a test copying machine used for evaluation of electrical characteristics, and 10 halftone images are printed in an N / N environment. Then, it is confirmed whether the periodicity formed per sheet of printing paper (A3 version) and the rotation period of the electrophotographic photosensitive member are coincident with each other, and visible black spots and white spots (diameter of 0.4 mm or more) are observed. The number was measured and the image quality was evaluated according to the following criteria.
A: Good (the total number of black spots and white spots is 3 or less on all printing papers).
B: No problem in practical use (the total number of black spots and white spots in all printing papers is 4 to 7 / sheet).
C: A practical level (the total number of black spots and white spots on all printing papers is 8 to 10 / sheet).
D: There is a problem in practical use (there is one or more printing papers in which the total number of black spots and white spots is 11 / sheet).

For Examples 2 to 4 and Comparative Examples 1 and 2, the electrical characteristics and image quality were evaluated in the same manner as in Example 1.
Table 1 shows the evaluation of electrical characteristics and image quality of Examples 1 to 4 and Comparative Examples 1 and 2.

  From the results of Table 1, it was found that Examples 1 to 4 were superior to Comparative Example 2 in terms of electrical characteristics, and Examples 1 to 4 were significantly superior to Comparative Examples 1 and 2 in terms of image quality.

Further, after the image quality evaluation, the surface of the electrophotographic photosensitive member was observed with an optical microscope, and a photograph of foreign matters on the conductive substrate corresponding to the positions of black spots and white spots was taken. An example is shown in FIGS.
FIG. 6 is a photograph of transparent foreign matters derived from microorganisms, FIG. 7 is a photograph of foreign matters of chips, and FIG. 8 is a photograph of foreign matters of cellulose fibers.
The transparent foreign substance and cellulose fiber foreign substance on the conductive substrate were white spots on the copy image, and the chip foreign substance was a black spot.

11, 21, 31, 41 Cleaning tank 18, 25, 35, 45 Cleaning liquid 17 Ultrasonic oscillator B Bubble supply unit b1 Bubble generator b2 Gas supply source P Electrophotographic photosensitive member S Conductive substrate

Claims (12)

  A cleaning tank that contains an aqueous cleaning solution, a bubble supply unit that supplies bubbles containing microbubbles not containing oxygen in the cleaning solution, and a conductive substrate for an electrophotographic photoreceptor in the cleaning solution supplied with the bubbles. An apparatus for cleaning a conductive substrate, comprising: a substrate transfer section for immersion.   The cleaning apparatus according to claim 1, wherein the bubble supply unit is configured to generate bubbles including microbubbles having an area average diameter of 0.1 to 100 μm.   The said bubble supply part has a bubble generator and the gas supply source which supplies the said bubble generator to the said bubble generator individually or 2 or more types selected from nitrogen, a carbon dioxide, argon, and helium. 2. The cleaning apparatus according to 2.   The bubble supply unit introduces the cleaning liquid in the cleaning tank into the bubble generator, generates micro bubbles in the cleaning liquid introduced into the bubble generator, and supplies the microbubbles to the cleaning liquid in the cleaning tank. The cleaning apparatus according to claim 3, which is configured as follows. The cleaning tank has a cleaning tank for storing a main cleaning aqueous cleaning liquid containing a surfactant, and a cleaning tank for storing a rinsing aqueous cleaning liquid not containing a surfactant.
The said bubble supply part is a washing | cleaning apparatus as described in any one of Claims 1-4 which supplies the bubble which consists of the cleaning gas which does not contain oxygen in the aqueous cleaning liquid for the said rinse.   6. The cleaning apparatus according to claim 5, further comprising an ultrasonic oscillator that oscillates ultrasonic waves in at least one of the aqueous cleaning liquid for main cleaning and the aqueous cleaning liquid for rinsing.   A method for cleaning a conductive substrate, comprising a step of immersing and cleaning a conductive substrate for an electrophotographic photosensitive member in an aqueous cleaning solution to which bubbles containing no oxygen are supplied.   The cleaning method according to claim 7, wherein the amount of dissolved oxygen in the cleaning liquid at the time of cleaning is 2 mg / L or less.   The cleaning method according to claim 7 or 8, wherein the bubbles have an area average diameter of 0.1 µm to 100 µm.   The cleaning method according to any one of claims 7 to 9, wherein the bubbles are made of one or more gases selected from nitrogen, carbon dioxide, argon, and helium. The method further includes a step of immersing and cleaning the conductive substrate in an aqueous cleaning solution for main cleaning containing a surfactant, as an initial cleaning step,
The cleaning method according to any one of claims 7 to 10, wherein the bubbles are supplied into a cleaning liquid in a cleaning step after the first cleaning step.   The cleaning method according to claim 7, wherein an ultrasonic wave is oscillated in the cleaning liquid.