JP4853257B2 - Method for producing electrophotographic photosensitive member - Google Patents

Description

  The present invention relates to a method for producing an electrophotographic photoreceptor.

  In recent years, electrophotographic photoreceptors having a charge generation layer and a charge transport layer containing an organic photoconductive substance have been widely used in electrophotographic image forming apparatuses. These photoconductors using organic materials are easy to develop materials corresponding to various exposure light sources from visible light to infrared light, can select materials with less environmental pollution, and have low manufacturing costs. For example, there are many advantages over a selenium photoreceptor. On the other hand, a photoreceptor using an organic material has low mechanical strength, and the surface of the photoreceptor is worn or scratched when a large number of sheets are printed, so that the durability is inferior to that of an inorganic photoreceptor.

  As a method for producing a photoreceptor using an organic substance, there is a method for producing a photoreceptor (hereinafter also simply referred to as a photoreceptor) formed by applying a photosensitive layer on a conductive support or a protective layer on the photosensitive layer. (For example, refer to Patent Document 1).

In addition, a method is disclosed in which a surface layer (protective layer) is cured by photocuring reaction in order to prevent wear deterioration and scratches on the surface of the photoreceptor. As a light source for performing a photocuring reaction, a method using ultraviolet light such as a mercury lamp or xenon is disclosed (for example, see Patent Documents 2 and 3).
JP-A-11-149164 JP 2001-166514 A JP 2001-125299 A

  However, a photoconductor produced by photocuring a photocurable coating film of a protective layer formed on the surface of the photoconductor using light such as a mercury lamp, a xenon lamp, or a metal halide lamp has a residual potential that increases with repeated use. The image problem that the image density decreases has occurred.

  Decreasing the amount of light used to photocure the photocurable coating to prevent image density reduction can resolve image density reduction, but photocuring is insufficient and wear of the protective layer increases, resulting in a problem with durability. It becomes.

  The present invention has been made for the purpose of solving the above-mentioned problems. Even when continuous printing (for example, 100 sheets) is performed, the increase in residual potential is small, and even when many sheets (for example, 100,000 sheets) are printed, the amount of wear is small. Another object of the present invention is to provide an excellent method for producing a photoreceptor, which has good transferability and cleanability, and can continuously obtain a high-density print image.

  The present invention is achieved by adopting the following configuration.

1.
In the method for producing an electrophotographic photosensitive member having a photosensitive layer and a protective layer on a conductive support,
The photosensitive layer has a phthalocyanine compound as a charge generation material and a triphenylamine compound as a charge transport material, and the protective layer has a step of photocuring with light emitting diode light. Manufacturing method.

2.
2. The method for producing an electrophotographic photosensitive member according to 1 above, wherein the light emitting diode light has a peak wavelength of 300 to 500 nm.

3.
3. The method for producing an electrophotographic photosensitive member according to 1 or 2, wherein the light-emitting diode light has a half-width of a peak wavelength of 30 nm or less.

  The method for producing a photoreceptor of the present invention has little increase in residual potential even after continuous printing (for example, 100 sheets), little wear even when printing a large number of sheets (for example, 100,000 sheets), transferability and cleaning performance. It has an excellent effect of providing an excellent photoconductor that can obtain a good and high density printed image continuously.

  In the photoreceptor having the photosensitive layer and the protective layer on the conductive support, the inventors apply a light such as a mercury lamp, a xenon lamp, or a metal halide lamp to the photocurable coating film (containing the resin-forming component) of the protective layer. The cause of the decrease in image density of the photoconductor produced by irradiation was examined. As a result of the examination, it was found that the residual potential increased with repeated charging and exposure.

  The increase in the residual potential is caused by irradiating light from a mercury lamp, a xenon lamp, a metal halide lamp or the like. Light from mercury lamps, xenon lamps, metal halide lamps, etc. is cured by photochemical reaction of resin-forming components (monomers and oligomers) in the protective layer, and at the same time compounds contained in the photosensitive layer and protective layer (for example, electron generating substances) And charge transport materials) are decomposed or chemically changed. As a result, it is assumed that the residual potential is rising.

  The inventors of the present invention have studied a method for producing a photoreceptor in which the resin-forming component of the protective layer is photocured without increasing the residual potential.

  As a result of various studies, a photoconductor produced by photochemical reaction of a resin-forming component (monomer or oligomer) with light-emitting diode (hereinafter, also referred to as LED) light suppresses an increase in residual potential even after continuous printing. It has been found that wear is also obtained.

  The reason why the increase in the residual potential could be kept low is that the LED light used in the present invention decomposes the compound in the photosensitive layer and the protective layer while there is a sufficient amount of wavelength for photochemical reaction of the resin-forming component in the protective layer. It is assumed that the amount of wavelength causing chemical change is small, so that the amount of compound decomposition or chemical change is small, and as a result, the increase in residual potential is suppressed.

  The LED light used in the present invention preferably has a specific peak wavelength and a full width at half maximum of the specific peak wavelength. A photoconductor produced by irradiating the LED light and photocuring the protective layer is preferable because the increase in residual potential is small, the wear amount is small, and the actual image characteristics (image density, transferability, cleaning properties) are satisfied.

  In particular, the method of performing photocuring by irradiating the protective layer with only monochromatic light necessary for curing is different from conventional light sources in that only the protective layer can be cured without causing deterioration of the underlying coating film and photosensitive layer.

  Further, the LED has high luminous efficiency with respect to power and high energy efficiency.

  Furthermore, unnecessary light has been a problem because, for example, oxygen in the air is ozonated, and an active gas is generated that degrades the coating film or the photosensitive layer. Thus, a good photoconductor can be obtained.

  Hereinafter, the present invention will be described in detail.

  The method for producing a photoreceptor of the present invention includes a step in which the protective layer is photocured by LED light.

  It does not specifically limit as an LED light source, The thing whose peak wavelength is 300-500 nm is preferable, and the thing whose peak wavelength half value width is 30 nm or less is preferable.

  By using an LED light source having the above characteristics, a compound (for example, a binder resin, an electron generating material or a charge transporting material) in a coating film (for example, an intermediate layer, a photosensitive layer or a protective layer) provided on a conductive support. Decomposition and chemical change can be suppressed, and the resin-forming components (for example, monomers and oligomers) in the protective layer can be photochemically reacted and cured well.

  FIG. 1 is a diagram showing an example of an emission power wavelength spectrum of an LED used in the present invention.

  In FIG. 1, the horizontal axis indicates the wavelength (nm) and the vertical axis indicates the emission intensity distribution. This LED exhibits an emission intensity distribution of 1.0 at 363 nm.

The LED preferably has a maximum illuminance of 2000 to 4000 mw / cm ² (beam diameter ψ3).

  The photoreceptor according to the present invention has a layer structure having a protective layer on the surface thereof. A protective layer is formed through the process of photocuring by irradiation of LED light.

  First, the layer structure of the photoreceptor will be described.

(Photoreceptor layer structure)
The photoreceptor according to the present invention is not particularly limited as long as it has a protective layer that is photocured on its surface.

  FIG. 2 is a schematic diagram showing an example of the layer structure of the photoreceptor according to the present invention.

  In FIG. 2, 100 is a conductive support, 200 is an intermediate layer, 300 is a photosensitive layer, 400 is a charge generation layer, 500 is a charge transport layer, and 600 is a protective layer.

2A shows a photosensitive member having a layer structure in which a photosensitive layer 300 containing a charge transporting material and a charge generating material and a protective layer 600 are sequentially laminated on the conductive support 100, and FIG. 2B shows a conductive support. A photoconductor having a layer structure in which a charge generation layer 400, a charge transport layer 500, and a protective layer 600 are sequentially laminated on 100;
(C) A photoconductor having a layer structure in which an intermediate layer 200, a charge generation layer 400, a charge transport layer 500, and a protective layer 600 are sequentially laminated on a conductive support 100 is shown.

  The photoconductor according to the present invention may have any of the above-described layer configurations. Among these, the photoconductor is prepared by providing an intermediate layer, a charge generation layer, a charge transport layer, and a protective layer on a conductive support ( (C) in FIG. 2 is preferred.

Next, the members and layers constituting the photoreceptor according to the present invention will be described (conductive support).
The conductive support used in the present invention is preferably cylindrical and has a specific resistance of 10 ³ Ωcm or less. As a specific example, cylindrical aluminum whose surface has been cleaned after cutting can be mentioned.

(Middle layer)
The intermediate layer is formed by applying and drying an intermediate layer coating liquid composed of a binder, inorganic particles, a dispersion solvent, and the like on a conductive support.

  Examples of the binder for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Among these resins, a polyamide resin is preferable because it can reduce a residual potential increase due to repeated use.

  As the solvent for preparing the coating solution for the intermediate layer, a solvent in which the inorganic particles to be added are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like are excellent in solubility and coating performance of the polyamide resin. These solvents are 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent. Examples of co-solvents that can be used in combination with the above-mentioned solvent to obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  Various conductive fine particles and inorganic particles such as metal oxides can be contained for the purpose of adjusting the resistance of the intermediate layer. For example, various metal oxides such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used. You may use these metal oxides 1 type or in mixture of 2 or more types. When two or more types are mixed, they may take the form of a solid solution or fusion. The average particle diameter of such a metal oxide is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  The thickness of the intermediate layer is preferably 0.2 to 40 μm, and more preferably 0.3 to 20 μm.

<Charge generation layer>
The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.01 to 2 μm.

<Charge transport layer>
When the charge transport layer is a surface layer, the charge transport layer is formed from the particles according to the present invention, a charge transport material (CTM), and a binder resin. Other substances may be formed by adding additives such as antioxidants as necessary. The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  When the charge transport layer forms the surface layer, the amount of the particles according to the present invention in the charge transport layer is preferably 5 to 80% by mass, and more preferably 10 to 50% by mass.

  A known charge transport material (CTM) can be used as the charge transport material (CTM). For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used.

  Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of the repeating units of these resins. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinylcarbazole can be used.

  Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  As the antioxidant, known compounds can be used. Specifically, “Irganox 1076”, “Irganox 1010”, “Irganox 1098”, “Irganox 245”, “Irganox 1330”, “ "Irganox 3114", "Irganox 1076", "3,5-di-tert-butyl-4-hydroxybiphenyl" or more hindered phenols, "Sanol LS2626", "Sanol LS765", "Sanol LS2626", "Sanol LS770 "," Sanol LS744 "," Tinuvin 144 "," Tinuvin 622LD "," Mark LA57 "," Mark LA67 "," Mark LA62 "," Mark LA68 "," Mark LA63 "or more hindered amine system," Smilizer TPS " , "Smilizer T -D "or more thioether type," Mark 2112 "," Mark PEP-8 "," Mark PEP-24G "," Mark PEP-36 "," Mark 329K "," Mark HP-10 "or more phosphite type It is done. Of these, hindered phenols and hindered amine antioxidants are particularly preferred. As for the addition amount of antioxidant, 0.1-10 mass parts is preferable with respect to 100 mass of total mass of resin layer solid content.

  The thickness of the charge transport layer is preferably 10 to 40 μm. By setting the film thickness within this range, the sensitivity of the photoreceptor can be ensured.

  In addition, as a method of providing the intermediate layer, the charge generation layer, and the charge transport layer on the conductive support, there are a spray coating method, a dip coating method, a circular amount regulation type coating method, or a combination method of the dip coating and the circular amount regulation type coating. preferable. The circular amount regulation type application is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

<Protective layer>
The protective layer can be obtained by forming a photocurable coating film having at least a precursor material and a polymerization initiator on the charge transporting layer, and then irradiating with LED light and photocuring.

  The precursor material includes 50% by mass or more of a non-volatile component having three or more acrolyl groups or metalloyl groups in one molecule, and specifically includes a curable acrylic monomer or oligomer. .

  Examples of the curable acrylic monomer or oligomer include the following compounds.

In the formula, R ₁ , R ₂ and R ₃ represent a hydrogen atom or an alkyl group, aryl group, alkenyl group or aralkyl group which has 10 or less carbon atoms and may have a substituent.

In the formula, R ₁ and R ₂ represent an alkyl, aryl, or alkenyl group having 10 or less carbon atoms having a vinyl group at the terminal and optionally having a substituent.

  Specific examples of the compound include pentaerythritol hexaacrylate, urethane acrylate oligomer, dipentaerythritol hexaacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, and the like.

As the polymerization initiator, benzophenone, Michler ketone, thioxanthone, benzobutyl ether, acyloxime ester, dibenzothroben, bisacylphosphine oxide, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2, 6-Difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butane Examples include -1-one, 1-hydroxy-cyclohexyl-phenyl ketone, and 1-hydroxycyclohexyl-phenyl ketone.

  These polymerization initiators are preferably selected so that the peak wavelength of the LED light source overlaps with the absorption peak wavelength, and it is preferable that the polymerization initiator has an absorption peak within ± 30 nm with respect to the peak wavelength of the LED light source. .

  The protective layer can be formed by adding a charge transport material, an antioxidant, inorganic fine particles, organic fine particles, an electric resistance adjusting agent, and the like as necessary.

  Inorganic fine particles include various metal oxides such as silica, alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony-doped tin oxide, and zirconium oxide. Can be mentioned. These inorganic fine particles may be used alone or in combination of two or more. The average particle size of such inorganic fine particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  Organic fine particles include ethylene tetrafluoride resin, ethylene trifluoride chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and copolymers thereof. Can be mentioned. These organic fine particles may be used alone or in combination. The average particle diameter of such organic fine particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  In particular, when the protective layer to which the fine particles are added is cured, it is desirable to cure using the LED light as in the present application.

  The thickness of the protective layer is preferably 0.2 to 5 μm, and more preferably 0.3 to 4 μm. By setting the film thickness within this range, it is possible to ensure the durability of the photoreceptor.

  As a method of providing a protective layer on the charge transport layer, a protective layer coating solution is spray-coated on the photosensitive layer to form a photocurable coating film, and the photocurable coating film is no longer fluid. After the secondary drying, a method of irradiating LED light to cure the photocurable coating film, and further performing secondary drying for the purpose of reducing the amount of volatile substances in the coating film is preferable.

  The spray coating liquid can be prepared by dissolving a precursor material (for example, a curable acrylic monomer or oligomer), the polymerization initiator, a charge transporting substance, and the like with a diluent solvent.

  The diluent solvent is not particularly limited as long as it dissolves the precursor UV-curing acrylic monomer or oligomer and the polymerization initiator, and specifically n-butyl alcohol, isopropyl alcohol, ethyl alcohol, methyl alcohol, methyl isobutyl ketone. And methyl ethyl ketone.

  In the present invention, the photocurable film is formed by irradiating the photocurable coating film with LED light. The photocured film is preferably formed by selecting the LED to be used (peak wavelength, half-width of peak wavelength, output), and controlling the irradiation intensity and irradiation time received by the photocurable coating film.

  As a device for irradiating the photocurable coating with LED light, a device capable of uniformly irradiating the photocurable coating and forming a uniform photocurable film is preferable. Specifically, it is preferable to use the apparatus described below.

  FIG. 3 is a schematic diagram illustrating an example of an apparatus that irradiates LED light.

  In FIG. 3, 1 is a photoreceptor on which a photocurable coating film is formed, 2 is an LED light source, and 3 is a distance between the photocurable coating and the LED.

  FIG. 3 (a) shows an apparatus in which an LED light source is set at a distance of about 10 mm from the photocurable coating film, and the LED light source is moved left and right while rotating the photosensitive member to irradiate the LED light. (B) shows the apparatus which irradiates LED light, setting many LED light sources in a line at a distance of about 10 mm from a photocurable coating film, and rotating a photoreceptor. (C) shows the apparatus which irradiates LED light, setting many LED light sources in a line at a distance of about 10 mm from the photocurable coating film and moving the photosensitive member up and down.

(Hardness of protective layer)
The hardness of the protective layer obtained by curing depends on the type of precursor material (for example, curable acrylic monomer or oligomer) to be used, the type and amount of polymerization initiator, the thickness of the protective layer, the irradiation conditions of pulsed light, and as required. It is influenced by the kind and amount of the charge transport material, antioxidant and electrical resistance adjusting agent to be added accordingly.

  In particular, it is affected by the type of curable acrylic monomer or oligomer, the composition ratio thereof, and the pulsed light irradiation conditions.

The hardness of the protective layer is preferably 50 to 400 N · mm ² , more preferably 300 to 400 N · mm ² in terms of universal hardness HU. By setting the hardness of the protective layer within the above range, wear of the protective layer can be reduced.

  The universal hardness can be measured by using a commercially available hardness measuring device, for example, an ultra-micro hardness meter “H-100V (manufactured by Fischer Instruments)”.

Measurement conditions Measuring instrument: micro hardness tester "H-100V (Fischer Instruments)"
Indenter shape: Vickers indenter (a = 136 °)
Measurement environment: 20 ° C, 60% RH
Maximum test load: 2mN
Loading speed: 2mN / 10sec
Maximum load creep time: 5 seconds Unloading speed: 2 mN / 10 sec
Each sample was measured at a total of 15 points of 5 points at equal intervals in the axial direction and 3 points at equal angles in the circumferential direction, and the average value was determined as universal hardness HU (N / mm ² ) defined in the present invention. To do.

  The image forming apparatus usable in the present invention includes a monochrome image forming apparatus that forms an image with a single color toner, a color image forming apparatus that sequentially transfers a toner image on a photosensitive member to an intermediate transfer member, and a plurality of images for each color. Examples thereof include a tandem type color image forming apparatus in which a photoreceptor is arranged in series on an intermediate transfer member.

  FIG. 4 is a cross-sectional configuration diagram showing an example of an image forming apparatus in which the photoreceptor according to the present invention is preferably used.

  In FIG. 4, 1Y, 1M, 1C and 1K are photoreceptors, 4Y, 4M, 4C and 4K are developing means, 5Y, 5M, 5C and 5K are primary transfer rollers as primary transfer means, and 5A is a secondary transfer. Secondary transfer rollers as means, 6Y, 6M, 6C and 6K are cleaning means, 7 is an intermediate transfer member unit, 24 is a heat roll type fixing device, and 70 is an intermediate transfer member.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. An endless belt-shaped sheet feeding / conveying means 21 and a heat roll type fixing device 24 as a fixing means. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, an image forming unit 10Y that forms a yellow image includes a drum-shaped photoconductor 1Y as a first photoconductor, and a periphery of the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image as another different color toner image is disposed around a drum-shaped photoconductor 1M as a first photoconductor, and the photoconductor 1M. A charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, and a cleaning unit 6M. In addition, an image forming unit 10C that forms a cyan image as one of other different color toner images is disposed around the photoconductor 1C as a drum-type photoconductor 1C as a first photoconductor. The charging unit 2C, the exposure unit 3C, the developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and a cleaning unit 6C are provided. Further, an image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photosensitive member 1K as a first photosensitive member, and the photosensitive member 1K. It has a charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit 6K.

  The endless belt-shaped intermediate transfer body unit 7 has an endless belt-shaped intermediate transfer body 70 as an intermediate transfer endless belt-shaped second image carrier that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rollers 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as a sheet as a transfer material accommodated in the sheet feeding cassette 20 is fed by the sheet feeding / conveying means 21, passes through a plurality of intermediate rollers 22 A, 22 B, 22 C, 22 D, and a registration roller 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roller 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by a heat roll type fixing device 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roller 5A, the residual toner is removed by the cleaning means 6A from the endless belt-shaped intermediate transfer body 70 in which the recording member P is separated by curvature.

  During the image forming process, the primary transfer roller 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roller 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, and 76, primary transfer rollers 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this way, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70, and are collectively applied to the recording member P The image is transferred, and fixed by pressing and heating with a heat roll type fixing device 24 and fixed. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above-described charging, exposure, and development cycle. The next image formation is performed.

<Transfer material>
The transfer material used in the present invention is a support for holding a toner image, and is usually called an image support, a transfer material, or transfer paper. Specific examples include various kinds of transfer materials such as plain paper from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic films for OHP, and cloth. However, it is not limited to these.

  The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.

<< Production of photoconductor >>
A photoreceptor was prepared according to the following procedure.

<Preparation of Photoreceptor 1>
(Preparation of conductive support)
The surface of the cylindrical aluminum support was cut and washed to prepare a conductive support.

(Formation of intermediate layer)
The following compounds were mixed to prepare a mixed solution.

Binder resin (N-1) 1 part by mass Ethanol / n-propyl alcohol / tetrahydrofuran (45:20:35 volume ratio) 20 parts by mass Surface-treated N-type semiconductive particles 1 (* 1) 4.2 parts by mass Above The mixed solution prepared in (1) was dispersed using a bead mill to prepare a coating solution for an intermediate layer. For dispersion, spherical beads (YTZ ball made by Nikkato Co., Ltd.) mainly composed of yttria-containing zirconium oxide having an average particle diameter of 0.1 to 0.5 mm are used, filling rate: 80%, peripheral speed setting 4 m / sec, mill residence time Was set at 3 hours. The dispersion was filtered through a 5 μm filter, and the intermediate layer coating solution was applied onto a washed conductive support by a dip coating method to form an intermediate layer having a dry film thickness of about 2 μm.

* 1 (Surface treatment N-type semiconductive particles 1)
The surface-treated N-type semiconductor particles 1 are produced as follows.

  0.2 part of methyl hydrogen polysiloxane is dissolved and dispersed in 10 parts of ethanol / n-propyl alcohol / THF (45:20:35 volume ratio), and rutile type titanium oxide (number average primary particle diameter) is dissolved in the mixed solvent. 35 nm: 5% primary surface treatment with alumina) is added (3.5 parts), followed by stirring for 1 hour, surface treatment (secondary treatment), separation from the solvent, heat drying and surface treatment N Type semiconductive particles 1 were produced.

(Formation of charge generation layer)
The following components were mixed and dispersed using a sand mill disperser to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

Y-titanyl phthalocyanine (a titanyl phthalosine pigment having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray) 20 parts by weight of polyvinyl butyral “ BX-1 (manufactured by Sekisui Chemical Co., Ltd.) "10 parts by mass Methyl ethyl ketone 700 parts by mass Cyclohexanone 300 parts by mass (Preparation of charge transport layer)
The following components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried to form a charge transport layer having a thickness of 18 μm.

Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl) triphenylamine) 50 parts by mass Polycarbonate resin “Iupilon-Z300 (manufactured by Mitsubishi Gas Chemical Company)”
100 parts by mass Antioxidant “Irganox 1010 (manufactured by Ciba Geigy Japan)” 8 parts by mass Tetrahydrofuran / toluene (volume ratio 8/2) 750 parts by mass (production of protective layer)
[Production of photocurable coating film]
Prepare coating solution for protective layer Curable material A (M408: Ditrimethylolpropane tetraacrylate)
0.3 part by mass Curable material B (E4858: molecular weight 450, bifunctional urethane acrylate)
0.7 parts by mass 1-propanol 5.1 parts by mass Methyl isobutyl ketone 2.4 parts by mass Furthermore, 0.6 parts by mass of fluororesin fine particles having a particle size of about 300 nm and anatase-type titanium oxide fine particles (particle size of about 6 nm, surface-treated methyl) 0.8 parts by mass of hydrogen silicone oil (20% by mass) was added and dispersed for 15 minutes with an ultrasonic homogenizer to prepare a dispersion containing a curable material, fluororesin fine particles, and titanium oxide fine particles.

  To the same dispersion, 0.05 parts by mass of a polymerization initiator 1-hydroxycyclohexyl-phenyl ketone (absorption peak: 365 nm) was added to prepare a coating solution for a protective layer.

  The protective layer coating solution prepared above was applied onto the charge transport layer by a dip coating method. Then, it dried at 100 degreeC for 5 minute (s), and "the photocurable coating film 1" was formed. In addition, the film thickness of the coating film was 3 micrometers.

[Photocuring of photocurable coating film]
Photocuring of the “photocurable coating film 1” formed above was performed under the following conditions.

LED irradiation apparatus: The apparatus described in FIG. 3B LED light source: LED with an output of 200 mw / cm ² (peak wavelength 365 nm, peak wavelength half width 30 nm)
Distance between LED light source and photocurable coating film: 10mm
Rotational speed of support: 10 rpm
Irradiation time: 3 minutes irradiation Thereafter, secondary drying was performed at 80 ° C. for 20 minutes to prepare “Photoreceptor 1”.

<Preparation of Photoreceptor 2>
“Photoreceptor 2” was prepared in the same manner except that the amount of light of the LED irradiated by photocuring of the photoreceptor 1 was changed twice (irradiation time was changed from 3 minutes to 6 minutes).

<Preparation of Photoreceptor 3>
“Photoreceptor 3” was produced in the same manner except that the amount of light emitted from the LED irradiated in the photocuring step of the photoreceptor 1 was changed to 0.5 times (irradiation time was changed from 3 minutes to 1.5 minutes).

<Preparation of Photoreceptor 4>
“Photoreceptor 4” was produced in the same manner except that the LED light source used in the photocuring step of photoconductor 1 was changed to an LED light source having a peak wavelength of 420 nm and a half width of 40 nm.

<Preparation of Photoreceptor 5>
“Photoreceptor 5” was produced in the same manner except that the LED light source used in the photocuring step of the photoreceptor 1 was changed to an LED light source having a peak wavelength of 550 nm and a half-value width of 30 nm.

<Preparation of Photoreceptor 6>
The polymerization initiator 1-hydroxycyclohexyl-phenylketone used in the production of the photoreceptor 1 was replaced with bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H- A “photoreceptor 6” was prepared in the same manner except that it was changed to pyrrol-1-yl) -phenyl) titanium (absorption peak: 400 nm).

<Preparation of photoconductor 7>
The polymerization initiator 1-hydroxycyclohexyl-phenylketone used in the preparation of the photoreceptor 1 was converted to 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butane. “Photoreceptor 7” was prepared in the same manner except that it was changed to -1-one (absorption peak: 320 nm).

<Preparation of Photoreceptor 8 (Comparative Example)>
A “photoreceptor 8” was produced in the same manner except that the light source used in the photocuring step of the photoreceptor 1 was changed from an LED to a high-pressure mercury lamp (2 kW).

<Preparation of Photoreceptor 9 (Comparative Example)>
A “photoreceptor 9” was produced in the same manner except that the light source used in the photocuring step of the photoreceptor 1 was changed from an LED to a metal halide lamp (2 kW).

<Preparation of Photoreceptor 10 (Comparative Example)>
“Photoconductor 10” was prepared in the same manner except that the light source used in the photocuring process of photoconductor 1 was changed from LED to xenon lamp (2 kW).

  Table 1 shows the absorption peak of the polymerization initiator, the type and output of the light source, and the peak wavelength. The half-value width of the peak wavelength, the LED light amount, and the hardness of the protective layer after photocuring are shown.

  In addition, the hardness of a protective layer is the value obtained by measuring with the above-mentioned method using the ultra micro hardness tester "H-100V (made by Fischer Instruments)."

<Evaluation>
Evaluation of the photoconductor was performed by sequentially mounting the photoconductors prepared above on a commercially available full-color multifunction peripheral “8050 (manufactured by Konica Minolta Business Technologies)”. In addition, (double-circle), (circle), and (triangle | delta) are pass, and x is disqualified.

In an environment of high temperature and high humidity (30 ° C., 80% RH), an A4 size original having a white background, solid black, red, green, and blue solid image portions and 1/4 character image portions on high-quality paper ( 100,000 sheets were printed at 64 g / m ² ). The intermediate transfer belt mounted with the “intermediate transfer belt 1” produced above.

(Increase in residual potential)
The residual potential was measured by removing the developing device and the cleaning device from the full-color composite machine and attaching a potential measuring device at that position. Specifically, the charging and exposure were repeated 100 times continuously, the first residual potential and the 100th residual potential were measured, and the difference was evaluated as an increase in the residual potential. If the increase in residual potential was less than 100 V, it was judged that there was no practical problem.

(Abrasion amount of coating layer)
The amount of wear of the coating layer was determined by measuring the thickness of the coating layer at the start of printing and at the end of printing 100,000 sheets by the following method, and the difference was defined as the amount of wear of the coating layer.

  As for the film thickness of the coating film layer, 10 portions of the uniform film thickness are measured randomly at the start of printing and at the end of printing 100,000 sheets, and the average value is taken as the film thickness of the coating film layer. As the film thickness measuring device, an eddy current type film thickness measuring device “EDDY560C (manufactured by HELMUT FISCHER GMBH CO)” was used. In addition, if the amount of wear of the coating layer is less than 1 μm, it is considered acceptable.

(Image density)
The image density was evaluated by the image density of the solid black image portion after printing 100 sheets continuously in A4 size, printing a solid black image.

  The image density was measured using a densitometer “RD-918” manufactured by Macbeth. The measurement was performed at a relative reflection density where the reflection density of the fine paper was “0”. In addition, if the image density is 1.2 or more, it is determined to be acceptable.

(Transferability)
The transferability was evaluated by printing an original solid image (20 mm × 50 mm) with a pixel density of 1.30 after printing 100,000 sheets and calculating the transfer rate according to the following equation.

Transfer rate (%) = (mass of toner transferred onto transfer material / mass of toner developed on photoreceptor) × 100
Evaluation Criteria A: Transferability is 95% or more and transferability is good. ○: Transfer rate is 90% or more and less than 95%, practically no problem. ×: Transfer rate is less than 90%, causing practical problems. .

(Evaluation of cleaning properties)
The evaluation of the cleaning property was carried out by using a deteriorated blade with an edge worn by 10 μm in a low temperature and low humidity (10 ° C., 15% RH) environment after printing 100,000 sheets and changing the spring load applied to the blade. Specifically, the spring load applied to the blade was changed in five stages, and the evaluation was performed based on the cleaning limit load (N / m) at which cleaning failure occurred when a solid image was cleaned. In addition, Rank 3 or higher is practical and acceptable.

Evaluation criteria Rank 5: The cleaning limit load is less than 9 N / m Rank 4: The cleaning limit load is 9 N / m or more and less than 13 N / m Rank 3: The cleaning limit load is 13 N / m or more and less than 17 N / m Rank 2: The cleaning limit load However, 17 N / m or more and less than 21 N / m Rank 1: The cleaning limit load is 21 N / m or more.

  Table 2 shows the evaluation results.

  From the results in Table 2, it can be seen that "Examples 1 to 7" of the present invention are excellent in all characteristics. However, it can be seen that “Comparative Examples 1 to 3” outside the present invention have problems with at least one of the characteristics.

It is a figure which shows an example of the emitted power wavelength spectrum of LED used by this invention. It is a schematic diagram showing an example of a layer structure of a photoreceptor used in the present invention. It is the schematic which shows an example of the apparatus which irradiates LED light. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus in which a photoreceptor according to the present invention is preferably used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Conductive support 200 Intermediate layer 300 Photosensitive layer 400 Charge generation layer 500 Charge transport layer 600 Protective layer

Claims (3)

In the method for producing an electrophotographic photosensitive member having a photosensitive layer and a protective layer on a conductive support,
The photosensitive layer has a phthalocyanine compound as a charge generation material and a triphenylamine compound as a charge transport material, and the protective layer has a step of photocuring with light emitting diode light. Manufacturing method. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the light emitting diode light has a peak wavelength of 300 to 500 nm. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the light-emitting diode light has a half width of a peak wavelength of 30 nm or less.

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