JP4773255B2 - Method for disassembling an electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to a method for decomposing an electrophotographic photosensitive member, and more particularly, to a method for decomposing an electrophotographic photosensitive member used for a copying machine, a printer, or the like.

  Electrophotographic photosensitive members (hereinafter referred to as “photosensitive members”) are widely used in copying machines, printers, and the like. The photoreceptor is mainly formed by attaching a photoreceptor drum in which a photosensitive layer is formed on an aluminum substrate and plastic flanges at both ends thereof. Some photosensitive layers use organic photoconductive materials and inorganic photoconductive materials, but organic materials are more toxic, cost, and more flexible in material design than inorganic materials. There are many advantages, and organic materials are now widely used.

  Among them, a photosensitive layer using an organic photoconductive material is a laminated type in which a charge generation layer containing a charge generation material and a charge transport layer containing a material for transporting the generated charge are laminated in this order. Shows excellent sensitization and occupies most of them in practical use.

  In some cases, the photosensitive drum is charged using a contact charger, or abnormal noise is generated when the photosensitive drum is cleaned. In order to prevent this, a vibration isolating material is attached inside the photoconductor. As this material, aluminum, plastic, rubber or the like is used.

  In order to recycle and reuse such a photoreceptor, the photoreceptor must be separated from the photoreceptor drum without damaging the flange. In order to easily perform such separation, the following various methods are known.

  (1) In order to easily separate the photosensitive drum and the flange, the shape of the photosensitive drum or the flange is devised (see, for example, Patent Documents 1 and 2).

  (2) The flange portion is extremely cooled and removed (see, for example, Patent Documents 3 to 5).

(3) In order to melt and separate the adhesive between the photosensitive drum and the flange, liquid or powder is injected into the gap between the photosensitive member and the flange (see, for example, Patent Document 6).
JP-A-9-114323 JP 2001-166628 A JP-A-9-187820 Japanese Patent Laid-Open No. 10-115938 Japanese Patent Laid-Open No. 10-143011 JP 2004-101825 A

However, the method (1) requires complicated processing on the photosensitive drum or the flange.
In the method (2), since it is necessary to use liquid nitrogen or the like as the coolant, storage and handling of the coolant are problematic.
In the method (3), it can be used only for a photoreceptor using a water-soluble adhesive, and in addition, it is necessary to process the flange for liquid or powder injection.
The present invention has been made in view of such circumstances, and provides a method for separating a flange from a photosensitive drum very easily.

The present invention provides an electrophotographic photosensitive member comprising a cylindrical photosensitive drum and flanges fitted to both ends thereof, the flange having a linear expansion coefficient larger than that of the photosensitive drum, and the electrophotographic photosensitive member. An object of the present invention is to provide a method for disassembling an electrophotographic photosensitive member characterized in that when the flange is removed, the flanged electrophotographic photosensitive member is heated and then cooled, and the flange is removed from the photosensitive drum.
It is preferable that the photosensitive drum and the flange separated from each other can be reused as they are as raw materials.
The fitting between the photosensitive drum and the flange is preferably performed without using an adhesive or the like.
The flange may be made of a synthetic resin, and when the electrophotographic photosensitive member is heated, it may be heated below the glass transition temperature of the synthetic resin used for the flange.
The photosensitive drum may be cylindrical, and may be composed of a conductive support base and a laminated organic photosensitive layer formed on the support base.

According to this invention, since the flange has a linear expansion coefficient larger than that of the photosensitive drum, when the electrophotographic photosensitive member is once heated and then cooled, the flange contracts more than the photosensitive drum during cooling, and the inner diameter of the photosensitive drum is reduced. There exists a temperature region in which the outer diameter of the flange is smaller than that. Therefore, the flange can be easily removed from the photosensitive drum in that temperature range.
Further, by using the present invention, the photosensitive drum and the flange can be easily separated without being damaged, and can be reused as they are as well as a material. In addition, when the photosensitive drum and the flange are separated from each other, it can be performed by an extremely easy procedure of heating only, and there is an advantage that costs other than heating are not required.

  The present invention will be described using embodiments. The present invention can be applied to separation of a photosensitive drum and a flange in a general electrophotographic photosensitive member.

  FIG. 1 is a sectional view of an electrophotographic photosensitive member of the present invention, and FIG. 2 is an exploded sectional view of the photosensitive member of FIG. The electrophotographic photosensitive member 1 includes a photosensitive drum 2, a flange 3, and a vibration isolating material 4. FIG. 3 is an enlarged cross-sectional view of the main part of the photosensitive drum 2. The photosensitive drum 2 is configured by laminating an undercoat layer 6, a charge generation layer 7 containing a charge generation material, and a charge transport layer 8 containing a material for transporting the generated charges in this order on a conductive support base 5. ing. Further, the charge generation layer 7 and the charge transport layer 8 form a photosensitive layer 9, and such a laminated type photoreceptor 9 is widely used. A protective layer 10 is used on the photosensitive layer 9 as necessary.

  Aluminum, copper, nickel, stainless steel, brass, or the like is used as the material of the conductive support base 5 used here. These materials are used after being processed into a cylindrical shape, a columnar shape, a belt shape or the like. In the practice of the present invention, it is a cylindrical conductive support substrate. In the present invention, the diameter of the cylindrical conductive support substrate is not limited.

  The undercoat layer 6 is formed on the conductive support substrate 5 for the purpose of covering the conductive support substrate with scratches or irregularities, and preventing deterioration of charging properties due to charge injection into the photosensitive layer. Between. The undercoat layer 6 is applied so that the film thickness is about 0.1 to 5 μm.

  Examples of the material of the undercoat layer 6 include polyamide, copolymer nylon, polyvinyl alcohol, polyurethane, polyester, epoxy, phenol resin, casein, cellulose, gelatin, and the like. These are dissolved in water and a solvent to provide a conductive support. Coating on the substrate 5. As the material for the undercoat layer, alcohol-soluble copolymer nylon is particularly desirable. Examples of the solvent material include lower alcohols such as methanol, ethanol and butanol, mixed solvents of chlorinated solvents such as dichloroethane, chloroform, trichloroethane, trichloroethylene and perchloroethylene and alcohol solvents.

  Zinc oxide, titanium oxide, tin oxide, indium oxide, silica, oxidation, etc. for the purpose of adjusting the volume low efficiency of the undercoat layer 6 and improving the repeated aging characteristics in a low temperature and low humidity environment. Inorganic pigments such as antimony may be included. In this case, it is preferable that the weight ratio of the pigment and the resin is 60/40 to 95/5.

  The charge generation layer 7 is mainly composed of a charge generation material that generates charges when irradiated with light, and is formed of a binder resin and, if necessary, a known binder, plasticizer, sensitizer, and the like. The charge generation layer 7 is applied so that the film thickness is about 0.5 to 5 μm.

  Examples of the charge generation material include perylene imides and perylene acid anhydrides, polycyclic quinone pigments such as quinacridone and anthraquinone, phthalocyanine pigments such as metal phthalocyanines, metal-free phthalocyanines, and halogenated metal-free phthalocyanines, and squalium dyes. Skeletons such as azulenium dye, thiapyrylium dye, carbazole skeleton, styryl stilbene skeleton, triphenylamine skeleton, dibenzothiophene skeleton, oxadiazole skeleton, fluorenone skeleton, bis stilbene skeleton, distyryl oxadiazole skeleton, distyryl carbazole skeleton Azo pigments, bisazo pigments containing a fluorene ring and a fluorenone ring, bisazo pigments containing aromatic amines, trisazo pigments, etc. Other additives, dissolved in an organic solvent together with, dispersed, applied onto the undercoat layer 6. The ratio of the charge generation material is 30 to 90% by weight of the entire charge generation layer coating solution.

  Examples of the binder resin include melamine resin, epoxy resin, silicone resin, polyurethane, phenoxy resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate, polyvinyl butyral, polyarylate, polyamide, polyester, and the like. These can be used alone or in combination of two or more. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene, toluene and xylene, N , N-dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide, and the like. These can be used alone or in combination of two or more.

  The charge transport layer 8 is mainly composed of a charge transport material capable of transporting the charge generated in the charge generation layer 7, and includes a binder resin, an antioxidant, a plasticizer, a sensitizer, a lubricant and the like as necessary. Formed from additives. The charge transport layer 8 is applied so that the film thickness is about 10 to 100 μm.

  Examples of charge transport materials include poly-N-vinyl carbazole and derivatives thereof, poly-γ-carbazolyl ethyl gourmet and derivatives thereof, bilene-formaldehyde condensates and derivatives thereof, polyvinyl bilene, polyvinyl phenanthrene, oxazole derivatives, oxodi Azole derivatives, imidazole derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylvirazoline, phenylhydrazones, hydrazone derivatives, 3-methyl-2 -Electron donating substances such as azine compounds having a benzothiazoline ring, or fluorenone derivatives, dibenzothiophene derivatives, intenothiophene derivatives, phenanthrenequinone derivatives, intenopyridine derivatives, Electronic demand substances such as xanthone derivatives, benzo [C] cinnoline derivatives, phenazine oxide derivatives, tetracyanoethylene, tetracyanoquinodimethane, promanyl, chloranil, benzoquinone, and the like, and these as binder resin and It is dissolved and dispersed in an organic solvent together with other additives and applied onto the charge generation layer 7. These charge transport materials may be used alone or in combination of two or more. The ratio of the charge transport material is 3 to 15% by weight of the entire charge transport layer coating solution.

  Examples of the binder resin include thermoplastic resins such as polycarbonate, polyarylate, polyvinyl butyral, polyamide, polyester, polyketone, polyvinyl ketone, polystyrene, polyacrylamide, and polysulfone, and thermosetting such as epoxy resin, polyurethane, phenol resin, and phenoxy resin. Resin. These can be used alone or in combination of two or more. Organic solvents include alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, dichloroethane, chloroform and chlorobenzene. Halogenated hydrocarbons such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether and other ethers, acetone, methyl ethyl ketone, cyclohexanone and other ketones, ethyl acetate, methyl acetate and other esters, Examples of the solvent include dimethylformamide and dimethyl sulfoxide. These may be used alone or in combination of two or more.

  Examples of the coating method for the undercoat layer 6, the charge generation layer 7, and the charge transport layer 8 include various coating methods such as dip coating, blade coating, and spray coating.

  The flange 3 is widely used that is attached to both ends of the drum and formed with a driving gear, or that a metal plate is attached to the photosensitive member for electrical conduction. Examples of the resin used for these flanges include thermoplastic resins such as polycarbonate, polyacetal, polyamide, and ABS resin.

Examples of the present invention are shown below. Aluminum cylindrical support base (outer diameter D0 = 30 mm, inner diameter D1 = 28.4 ± 0.03 mm, longitudinal length L = 340 mm) (linear expansion coefficient 2.55 × 10 ⁻⁵ / ° C. (20-30) In order to form an undercoat layer thereon, 10 parts by weight of titanium oxide (TTO55A: manufactured by Ishihara Sangyo Co., Ltd.) and 10 parts by weight of copolymer nylon (CM8000: manufactured by Toray Industries, Inc.) are added to 159 parts by weight of methanol. In addition to a mixed solvent of 1,3-dioxolane and 106 parts by weight, an undercoat layer coating solution was prepared by dispersing in a paint shaker for 8 hours. Thereafter, an undercoat layer having a layer thickness of 0.9 μm was formed by drying and air drying, in order to form a charge generation layer on the undercoat layer, 2 parts by weight of a crystalline oxotitanium phthalocyanine crystal, 1 part by weight of a resin resin (Sekisui Chemical Co., Ltd .: ESREC BM-2) and 97 parts by weight of methyl ethyl ketone were mixed and dispersed with a paint shaker to prepare a coating solution for charge generation layer. In the same dip coating method as in the case of the intermediate layer, it is applied onto the previously formed intermediate layer and naturally dried to form a charge generation layer having a layer thickness of 0.2 μm. Formula (I) below

  5 parts by weight of an enamine compound, 9 parts by weight of a polycarbonate resin G400 (made by Idemitsu Kosan Co., Ltd.) as a binder resin, and 0.05 parts by weight of a Sumilizer BHT (made by Sumitomo Chemical Co., Ltd.) as an antioxidant The mixture was mixed to prepare a coating solution for charge transport layer using 47 parts by weight of tetrahydrofuran as a solvent, and a charge transport layer was formed by a dip coating method. Heat treatment was performed at a temperature of 130 ° C. for 1 hour to form a charge transport layer having a total layer thickness of 25 μm. The photosensitive drum thus prepared was used in the following examples and comparative examples.

<Example 1>
A flange 3 made of polycarbonate (linear expansion coefficient: 7.0 × 10 ⁻⁵ / ° C., glass transition temperature: 140 ° C.) having an outer diameter D2 = 28.5 ± 0.03 mm was fitted into the photosensitive drum by a press-fitting method. . The insertion length is 16 mm. This electrophotographic photosensitive member was sufficiently heated in a heater at 130 ° C., then taken out from the heater and naturally cooled with outside air. Immediately after the temperature of the electrophotographic photosensitive member was sufficiently lowered, the flange was removed, and the flange was removed by simply pulling it by hand. In addition, the photoconductor drum and the flange were not damaged or deformed, and both could be reused as they were.

<Comparative Example 1>
Although the flange was removed without heating the electrophotographic photosensitive member using the same photosensitive drum and flange as in Example 1, it did not come off even when pulled with force. Therefore, the flange and its surroundings were mechanically hit and the flange was removed. At this time, the flange was damaged, and the photosensitive drum was also scratched and deformed, and neither of them could be reused as it was.

<Comparative example 2>
Using the same photosensitive drum and flange as in Example 1, the fitting part was bonded with epoxy resin. The electrophotographic photosensitive member was sufficiently heated with a heater at 130 ° C., then taken out from the heater and naturally cooled with outside air. Immediately after the temperature of the electrophotographic photosensitive member was sufficiently lowered, the flange was removed, but it did not come off when pulled with force. Therefore, the flange and its surroundings were mechanically hit and the flange was removed. At this time, the flange was damaged, and the photosensitive drum was also scratched and deformed, and neither of them could be reused as it was.

<Comparative Example 3>
Flange 3 made of the same photosensitive drum as in Example 1 and a phenol resin containing a glass fiber having an outer diameter of 28.5 ± 0.03 mm (linear expansion coefficient 1.6 × 10 ⁻⁵ / ° C., glass transition temperature 150 ° C.) Was inserted by a press-fitting method. The electrophotographic photosensitive member was sufficiently heated in a heater at 140 ° C., then taken out from the heater and naturally cooled with outside air. Immediately after the temperature of the electrophotographic photosensitive member was sufficiently lowered, the flange was removed, but the flange did not come off even when it was pulled with force. Therefore, the flange and its surroundings were mechanically hit and the flange was removed.
At this time, the drum was reusable, but the flange was damaged and could not be reused as it was.
These are summarized in Table 1.

Here, the reason why the flange can be easily removed from the photosensitive drum in the first embodiment will be described based on temperature changes of the inner diameter D1 of the photosensitive drum and the outer diameter D2 of the flange.
First, the case of a no-load state (a state where no flange is fitted to the drum) will be described with reference to FIG. The drum inner diameter D1 and flange outer diameter D2 differ greatly in the rate of change (inclination) of D1 and D2 when the temperature rises to 130 ° C. due to the difference in the linear expansion coefficient of the material. In addition, the slope during natural cooling is naturally larger in D2. (In addition, since it takes time to dissipate heat during natural cooling, both the slopes D1 and D2 are smaller than those during temperature rise.)

Next, the case of the fitting state will be described with reference to FIG.
Drum inner diameter D1 and flange outer diameter D2 before fitting are D1 = 28.4 mm and D2 = 28.5 mm, respectively, but when fitted, D1 is slightly larger and D2 is slightly smaller due to the difference in material. (D1 = D2 = 28.48 mm).

When the temperature is raised from this state, D2 tends to increase because of its large linear expansion coefficient, but is pressed down to D1 having a small linear expansion coefficient, and the dimension itself shows the same increase pattern at 28.degree. Both expand to 57mm.
After that, when entering natural cooling, D2 expands somewhat under the influence of the compressive stress received during fitting while taking the same shrinkage pattern (steep inclination) as in the case of no load, before fitting. Return to dimension 28.5mm.
On the other hand, D1 contracts while having an inclination close to that of no-load contraction (FIG. 4).
At point A in FIG. 5 where the temperature has dropped to a certain temperature, D1 = D2 = 28.5 mm. D1 attempts to return to the unloaded dimension of 28.4 mm, but settles at 28.48 mm at the beginning of fitting due to the influence of D2.

Therefore, before point A (about 30 to 40 ° C.) where D2 is smaller than D1, the flange can be removed with a light force.
If the flange is removed at a temperature before point A, the flange outer diameter D2 will maintain the dimension of 28.5 mm, and the base body inner diameter D1 will shrink to 28.4 mm with no load. Is possible.

1 is a cross-sectional view of an electrophotographic photoreceptor according to the present invention. FIG. 2 is an exploded cross-sectional view of the photosensitive drum in FIG. 1. It is a principal part enlarged view of FIG. 6 is a graph showing temperature changes of the inner diameter of the photosensitive drum and the outer diameter of the flange in the present invention. 6 is a graph showing temperature changes of the inner diameter of the photosensitive drum and the outer diameter of the flange in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photosensitive member 2 Photosensitive drum 3 Flange 4 Anti-vibration material 5 Conductive support base 6 Undercoat layer 7 Charge generation layer 8 Charge transport layer 9 Photosensitive layer 10 Protective layer

Claims (5)

In an electrophotographic photosensitive member having a cylindrical photosensitive drum and flanges inserted by fitting into both ends thereof, the flange has a linear expansion coefficient larger than that of the photosensitive drum, and when removing the flange of the electrophotographic photosensitive member In addition, the electrophotographic photosensitive member with the flange attached is heated and then naturally cooled, and the flange is removed from the photosensitive drum at a timing when the outer diameter of the flange becomes smaller than the inner diameter of the photosensitive drum. Method for disassembling the photoreceptor   2. The method of disassembling an electrophotographic photosensitive member according to claim 1, wherein the photosensitive drum and the flange separated from each other can be reused as they are as raw materials.   2. The method of disassembling an electrophotographic photosensitive member according to claim 1, wherein the fitting between the photosensitive drum and the flange is performed without using an adhesive or the like.   The decomposition of the electrophotographic photosensitive member according to claim 1, wherein the flange is made of a synthetic resin, and the electrophotographic photosensitive member is heated at a temperature equal to or lower than a glass transition temperature of the synthetic resin used for the flange. Method.   2. The method for decomposing an electrophotographic photosensitive member according to claim 1, wherein the photosensitive drum is cylindrical and comprises a conductive support substrate and a laminated organic photosensitive layer formed on the support substrate.

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