JP6237188B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus and an image forming method.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus is required to have a long life and image quality stability. The life of a photoreceptor, which is an important functional member in an image forming apparatus, is determined by the degree of wear of the photosensitive layer. Further, the occurrence of minute scratches or uneven wear causes image quality deterioration, and the image forming unit including the photosensitive member needs to be replaced.

  In recent years, a protective layer made of a cross-linked curable resin is laminated on the surface of a photoreceptor to improve wear resistance, scratch resistance, and environmental stability, and to extend the life.

  In recent years, as a charging method for photoconductors, it is advantageous for high image quality and apparatus miniaturization, and proximity charging that can reduce the generation amount of oxidizing gases such as ozone and NOx compared to scorotron and corotron charging methods. The method is adopted.

  However, when a proximity charging method is applied to a photoreceptor having a protective layer made of a crosslinkable curable resin, the refreshability of the photoreceptor surface deteriorates as the surface polishing rate decreases, and the deterioration rate of the photoreceptor surface becomes There is a problem that the speed is higher than the polishing speed, the torque is increased by the attached discharge product, and cleaning failure or toner filming due to the peeling or chipping of the cleaning blade is caused.

  In order to improve toner cleaning properties, a method is known in which a lubricant is applied to the surface of a photoconductor to form a film on the photoconductor to reduce the adhesion of toner. Thereby, the torque of the cleaning blade can be reduced, and the cleaning performance is improved.

  However, when a lubricant is applied to the surface of the photoreceptor and charged by the proximity charging method, the lubricant is deteriorated due to discharge, and the lubricant is changed into a water-absorbing substance. There is a problem that image flow occurs.

In order to solve such problems, it is necessary to remove the deteriorated lubricant and constantly supply new lubricant.
Cited Document 1 describes an image forming apparatus having a configuration in which a lubricant removing means for removing powder lubricant by a non-contact electrostatic roller is disposed downstream of a cleaning means. However, there is a problem that the film-like lubricant cannot be removed by the lubricant removing means of the image forming apparatus.
Also, the cited document 2 describes an image forming apparatus configured to adjust the amount of the lubricant by providing the cleaning unit with a lubricant removing unit. However, depending on the image forming apparatus, a lubricant that has not deteriorated may be removed at the time of cleaning, and sufficient cleaning properties cannot be obtained.

JP-A-5-224453 JP-A-5-181299

  The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an image forming apparatus that has good toner cleaning properties and suppresses the occurrence of image flow in a high-temperature and high-humidity environment. An object is to provide an image forming method.

The image forming apparatus of the present invention includes a photoreceptor having a protective layer containing a crosslinked polymer obtained by curing a polymerizable compound, a proximity charging unit that charges the surface of the photoreceptor by a proximity charging method, An exposure unit that exposes the photosensitive member charged by the proximity charging unit; a developing unit that supplies toner to the photosensitive member exposed by the exposing unit to form a toner image; and a toner image formed on the photosensitive member. Transfer means for transferring toner, lubricant supply means for supplying lubricant to the surface of the photoreceptor, cleaning means for removing toner remaining on the surface of the photoreceptor, and lubricant for removing the lubricant from the surface of the photoreceptor. An image forming apparatus comprising: a removing unit;
The lubricant supply means is disposed upstream of the cleaning means in the rotation direction of the photoconductor,
The lubricant removing means is disposed on the downstream side of the cleaning means in the rotation direction of the photoconductor and is disposed in contact with the surface of the photoconductor , and mechanically rubs the surface of the photoconductor to remove the lubricant. Having a brush roller to remove,
After supplying the lubricant by the lubricant supplying means, the ratio of the lubricant per unit area on the surface of the photoreceptor before the toner removal by the cleaning means is A (atom%), and after removing the lubricant by the lubricant removing means. It is characterized in that A ≧ 5.0B and B ≦ 0.20 are satisfied, where B (atom%) is the lubricant presence ratio per unit area of the photoreceptor surface.

  In the image forming apparatus of the present invention, it is preferable that the lubricant contains zinc stearate.

  In the image forming apparatus according to the aspect of the invention, it is preferable that the lubricant supply unit includes a solid lubricant and a lubricant application member.

The image forming method of the present invention comprises a proximity charging step of charging the surface of a photoreceptor having a protective layer containing a crosslinked polymer obtained by curing a polymerizable compound by a proximity charging method, and charging by the proximity charging step. An exposure step of exposing the photoconductor, a developing step of supplying a toner to the photoconductor exposed by the exposure step to form a toner image, and a transfer step of transferring the toner image formed on the photoconductor A lubricant supplying step for supplying a lubricant to the surface of the photoconductor, a cleaning step for removing toner remaining on the surface of the photoconductor, and a lubricant removing step for removing the lubricant from the surface of the photoconductor. An image forming method comprising:
The lubricant supply process is performed before the cleaning process,
The lubricant removing step is performed after the cleaning step, and a brush roller is placed in contact with the surface of the photoconductor, and the surface of the photoconductor is mechanically rubbed by the brush roller to remove the lubricant. Is,
A (atom%) is the lubricant present ratio per unit area of the photoreceptor surface before the cleaning process after the lubricant supplying process, and the lubricant per unit area of the photoreceptor surface after the lubricant removing process. When the existence ratio is B (atom%), A ≧ 5.0B and B ≦ 0.20 are satisfied.

  In the image forming method of the present invention, in the lubricant supplying step, the fine powder lubricant externally added to the toner is supplied to the photoreceptor by the action of the developing electric field formed in the developing step. preferable.

  In the image forming method of the present invention, it is preferable that the lubricant contains zinc stearate.

  According to the image forming apparatus of the present invention, after the lubricant is supplied by the lubricant supplying means and before the toner is removed by the cleaning means, the ratio of the lubricant per unit on the surface of the photoreceptor is A (atom%), and the lubricant removing means is used. When the ratio of the lubricant per unit on the surface of the photoreceptor after removal of the lubricant is B (atom%), satisfying A ≧ 5.0B and B ≦ 0.20 has good toner cleaning properties. At the same time, it is possible to suppress the occurrence of image flow in a high temperature and high humidity environment.

  According to the image forming method of the present invention, the ratio of the lubricant per unit of the photoreceptor surface after the lubricant supplying process and before the cleaning process is A (atom%), and the surface of the photoreceptor surface after the lubricant removing process is used. When the ratio of lubricant per unit is B (atom%), satisfying A ≧ 5.0B and B ≦ 0.20, the toner has a good toner cleaning property and is imaged in a high temperature and high humidity environment. Flow generation can be suppressed.

1 is a cross-sectional view illustrating an example of a configuration of an image forming apparatus according to the present invention. FIG. 2 is an explanatory cross-sectional view illustrating an example of a configuration of a main part of the image forming apparatus of the present invention.

  Hereinafter, the present invention will be described in detail.

[Image forming apparatus]
FIG. 1 is an explanatory sectional view showing an example of the configuration of the image forming apparatus of the present invention.
This image forming apparatus 100 is called a tandem type color image forming apparatus, and includes four sets of image forming units 110Y, 110M, 110C, and 110Bk, an intermediate transfer body unit 130, a paper feeding / conveying means 150, and a fixing means. 170. A document image reading device SC is arranged on the upper part of the main body of the image forming apparatus 100.

  The image forming units 110Y, 110M, 110C, and 110Bk are arranged side by side in the vertical direction. The image forming units 110Y, 110M, 110C, and 110Bk each include a drum-shaped photoreceptor 111Y, 111M, 111C, and 111Bk that is rotated, and a proximity charging unit 113Y that is sequentially disposed along the rotation direction of the photoreceptor in the outer surface area. 113M, 113C, 113Bk, exposure means 115Y, 115M, 115C, 115Bk, development means 117Y, 117M, 117C, 117Bk, lubricant supply means 114Y, 114M, 114C, 114Bk, cleaning means 119Y, 119M, 119C, 119Bk and lubricant removing means 116Y, 116M, 116C, 116Bk. Then, toner images of yellow (Y), magenta (M), cyan (C), and black (Bk) are formed on the photoreceptors 111Y, 111M, 111C, and 111Bk, respectively. Since the image forming units 110Y, 110M, 110C, and 110Bk are configured similarly except that the colors of the toner images formed on the photoconductors 111Y, 111M, 111C, and 111Bk are different, the following description will be made with an example of the image forming unit 110Y. .

[Photoreceptor]
The photoreceptor 111Y has a protective layer containing a crosslinked polymer obtained by curing a polymerizable compound. Specifically, the photoreceptor 111Y of this example has an intermediate layer on a conductive support, and a charge generation layer containing a charge generation material and a charge transport material containing a charge transport material on the intermediate layer. A photosensitive layer is formed by laminating layers in this order, and a protective layer is formed as a surface layer on the photosensitive layer (charge transport layer). The photosensitive layer may have a single-layer structure including a charge generation material and a charge transport material.

(Polymerizable compound)
The cross-linked polymer constituting the protective layer is a cross-linked curable resin obtained by polymerizing a polymerizable compound by irradiation with actinic rays such as ultraviolet rays and electron beams to form a cross-linked bond by a cross-linking reaction and curing it. . As the polymerizable compound, those having two or more polymerizable functional groups can be used, and those having one polymerizable functional group can be used in combination. Specifically, examples of the polymerizable compound include styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, N-vinyl pyrrolidone monomers, and the like.

As the polymerizable compound, an acrylic monomer having two or more acryloyl groups (CH ₂ ═CHCO—) or methacryloyl groups (CH ₂ ═CCH ₃ CO—) can be cured with a small amount of light or in a short time. Or it is especially preferable that they are these oligomers.

  In this invention, a polymeric compound may be used individually by 1 type, or may mix and use 2 or more types. In addition, these polymerizable compounds may use monomers, but may be used after oligomerization.

  Specific examples of the polymerizable compound are shown below.

However, in the chemical formulas showing the exemplified compounds M1 to M14, R represents an acryloyl group (CH ₂ ═CHCO—), and R ′ represents a methacryloyl group (CH ₂ ═CCH ₃ CO—).

(Metal oxide fine particles)
The protective layer may contain metal oxide fine particles. Moreover, it is preferable that the metal oxide fine particles have been surface-treated with a surface treatment agent.

  Examples of the metal oxide fine particles include silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina (aluminum oxide), zirconium oxide, tin oxide, titania (titanium oxide), niobium oxide, molybdenum oxide, vanadium oxide. Among them, tin oxide is preferable from the viewpoints of hardness, conductivity, and light transmittance.

  The number average primary particle size of the metal oxide fine particles is preferably 1 to 300 nm, more preferably 3 to 100 nm, and still more preferably 5 to 40 nm.

  In the present invention, the number average primary particle size of the metal oxide fine particles is a photographic image obtained by taking a magnified photograph of 10,000 times with a scanning electron microscope (manufactured by JEOL Ltd.) and randomly capturing 300 particles with a scanner (aggregation). The number average primary particle size was calculated using an automatic image processing analyzer “LUZEX AP (software version Ver. 1.32)” (manufactured by Nireco Corporation).

As the surface treatment agent, those that react with a hydroxy group or the like present on the surface of the metal oxide fine particles are preferable. Examples of such a surface treatment agent include a silane coupling agent and a titanium coupling agent.
Moreover, as a surface treating agent, the surface treating agent which has a radically polymerizable reactive group is preferable. Examples of the radical polymerizable reactive group include a vinyl group, an acryloyl group, and a methacryloyl group. Such a radical polymerizable reactive group can react with the polymerizable compound according to the present invention to form a strong protective layer. As the surface treatment agent having a radical polymerizable reactive group, a silane coupling agent having a radical polymerizable reactive group such as a vinyl group, an acryloyl group, or a methacryloyl group is preferable.

  Hereinafter, specific examples of the surface treatment agent will be shown.

_{S-1: CH 2 = CHSi} (CH 3) (OCH 3) 2
_{S-2: CH 2 = CHSi} (OCH 3) 3
S-3: CH ₂ = CHSiCl _{3
S-4: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5: CH 2 = CHCOO} (CH 2) 2 Si (OCH 3) 3
_{S-6: CH 2 = CHCOO} (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7: CH 2 = CHCOO} (CH 2) 3 Si (OCH 3) 3
_{S-8: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) Cl 2
_{S-9: CH 2 = CHCOO} (CH 2) 2 SiCl 3
_{S-10: CH 2 = CHCOO} (CH 2) 3 Si (CH 3) Cl 2
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13: CH 2 = C} (CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17: CH 2 = C} (CH 3) COO (CH 2) 2 SiCl 3
_{S-18: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19: CH 2 = C} (CH 3) COO (CH 2) 3 SiCl 3
_{S-20: CH 2 = CHSi} (C 2 H 5) (OCH 3) 2
_{S-21: CH 2 = C} (CH 3) Si (OCH 3) 3
_{S-22: CH 2 = C} (CH 3) Si (OC 2 H 5) 3
_{S-23: CH 2 = CHSi} (OCH 3) 3
_{S-24: CH 2 = C} (CH 3) Si (CH 3) (OCH 3) 2
_{S-25: CH 2 = CHSi} (CH 3) Cl 2
_{S-26: CH 2 = CHCOOSi} (OCH 3) 3
_{S-27: CH 2 = CHCOOSi} (OC 2 H 5) 3
_{S-28: CH 2 = C} (CH 3) COOSi (OCH 3) 3
_{S-29: CH 2 = C} (CH 3) COOSi (OC 2 H 5) 3
_{S-30: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-35: CH 2 = CHCOO} (CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-36: CH 2 = CHCOO} (CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2

  You may use a surface treating agent individually by 1 type or in mixture of 2 or more types.

  It is preferable that the usage-amount of a surface treating agent is 0.1-200 mass parts with respect to 100 mass parts of untreated metal oxide fine particles, More preferably, it is 7-70 mass parts.

  Examples of the treatment method for the untreated metal oxide fine particles of the surface treatment agent include a method of wet crushing a slurry (solid particle suspension) containing the untreated metal oxide fine particles and the surface treatment agent. By this method, re-aggregation of the untreated metal oxide fine particles is prevented, and at the same time, the surface treatment of the untreated metal oxide fine particles proceeds. Thereafter, the solvent is removed to form powder.

  The content of the metal oxide fine particles in the protective layer is preferably 20 to 170 parts by mass, more preferably 25 to 130 parts by mass with respect to 100 parts by mass of the crosslinked polymer.

  The protective layer may contain other components in addition to the crosslinked polymer and metal oxide fine particles. For example, various antioxidants can be contained, and various lubricant particles can be added. For example, fluorine atom-containing resin particles can be added. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluorinated ethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

  The protective layer is prepared by adding a polymerizable compound, metal oxide fine particles, a polymerization initiator and, if necessary, other components to a known solvent to prepare a coating solution. This coating solution is used as a photosensitive layer (charge transport layer). Formed by coating the outer peripheral surface to form a coating film, drying this coating film, and irradiating active rays such as ultraviolet rays and electron beams to polymerize and cure the polymerizable compound components in the coating film can do.

  The protective layer as described above is formed as a cross-linked curable resin by a reaction between polymerizable compounds and the like.

  As the solvent used for forming the protective layer, any solvent can be used as long as the polymerizable compound and the metal oxide fine particles can be dissolved or dispersed. For example, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n- Butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and Although diethylamine etc. are mentioned, it is not limited to these.

  As a coating method of the coating liquid for forming the protective layer, for example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method, etc. are known. The method is mentioned.

  The coating film may be cured without being dried, but it is preferable to perform the curing treatment after natural drying or heat drying.

  Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 minute to 200 minutes, and particularly preferably 5 minutes to 100 minutes.

  Examples of the method of reacting the polymerizable compound include a method of reacting by electron beam cleavage and a method of reacting with light and heat by adding a radical polymerization initiator. As the radical polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. A photopolymerization initiator and a thermal polymerization initiator can also be used in combination.

Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylazobisvaleronyl), 2,2′-azobis (2-methyl). Azo compounds such as butyronitrile); benzoyl peroxide (BPO), di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide, etc. And peroxides.
Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (“Irgacure 369” manufactured by BASF Japan Ltd.), 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) Acetophenone or ketal photoinitiators such as oximes; benzoin, benzoin methyl ether Benzoin ether photopolymerization initiators such as benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether; benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoyl Benzophenone photopolymerization initiators such as phenyl ether, acrylated benzophenone, 1,4-benzoylbenzene; 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4- Examples thereof include thioxanthone photopolymerization initiators such as dichlorothioxanthone.
Examples of other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and bis (2,4,6-trimethylbenzoyl). Phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compounds, triazine compounds, imidazole compounds, etc. Can be mentioned. In addition, a photopolymerization accelerator having a photopolymerization promoting effect can be used alone or in combination with the photopolymerization initiator. Examples of the photopolymerization accelerator include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, and 4,4′-dimethylaminobenzophenone. Etc.

  As the radical polymerization initiator, a photopolymerization initiator is preferable, and an alkylphenone compound or a phosphine oxide compound is particularly preferable. In particular, a compound having an α-aminoalkylphenone structure or an acylphosphine oxide structure is preferable.

  One polymerization initiator may be used alone, or two or more polymerization initiators may be mixed and used.

  It is preferable that the addition ratio of a polymerization initiator is 0.1-20 mass parts with respect to 100 mass parts of polymeric compounds, More preferably, it is 0.5-10 mass parts.

  A cross-linked polymer is produced by irradiating a coating film containing a polymerizable compound with active rays, generating radicals, polymerizing, and forming a cross-linking bond by a cross-linking reaction between molecules and within a molecule and curing. . As the actinic radiation, ultraviolet rays and electron beams are more preferred, and ultraviolet rays are particularly preferred because they are easy to use.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or the like can be used.
Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 100 mJ / cm ² .
The power of the lamp is preferably 0.1 kW to 5 kW, particularly preferably 0.5 kW to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary amount of active ray irradiation is preferably 0.1 second to 10 minutes, and more preferably 0.1 second to 5 minutes from the viewpoint of work efficiency.

  In the step of forming the protective layer, drying can be performed before and after irradiation with active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining these.

The universal hardness of the protective layer is preferably 200 or more and 700 or less, more preferably 280 or more and 600 or less.
The universal hardness of the protective layer is a value measured by an ultra micro hardness tester “H100SMC” (manufactured by Fisher Instruments).
The universal hardness of the protective layer can be controlled by the curing treatment conditions (active ray irradiation time and active ray type) when forming the protective layer and the type of polymerizable compound.

  The thickness of the protective layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

  In the photoreceptor of the present invention, various known layers can be employed other than the protective layer.

[Proximity charging means]
The proximity charging unit 113Y is a unit that charges the surface of the photoreceptor 111Y by a proximity charging method.
Here, the proximity charging method refers to a charging method using proximity discharge generated in a minute gap near the surface of the photoreceptor. Specifically, the proximity charging method includes a contact roller charging method, a non-contact roller charging method, a brush charging method, and the like.
The proximity charging unit 113Y in this example includes a charging roller disposed in contact with the surface of the photoreceptor 111Y and a power source that applies a voltage to the charging roller.
The charging roller is formed by, for example, forming a resistance adjustment layer on a conductive support.

[Exposure means]
The exposure unit 115Y exposes the surface of the photoreceptor 111Y to which the uniform potential is applied by the proximity charging unit 113Y based on an image signal (yellow image signal), and generates an electrostatic latent image corresponding to the yellow image. Means to form. As the exposure means 115Y, a device composed of an LED in which light emitting elements are arranged in an array in the axial direction of the photoconductor 111Y and an imaging element, or a laser optical system is used.

[Development means]
The developing unit 117Y is a unit that supplies toner to the surface of the photoreceptor 111Y, develops the electrostatic latent image formed on the surface of the photoreceptor 111Y, and forms a toner image. Specifically, the developing means 117Y of this example has a direct current and / or an alternating current for forming a developing electric field between the developing sleeve and the photosensitive member that rotates while holding a developer with a built-in magnet. It is comprised by the voltage application apparatus which applies a bias voltage.

[Lubricant supply means]
The lubricant supply means 114Y is a means for supplying a lubricant to the surface of the photoreceptor 111Y. The lubricant supply unit 114Y is upstream of the cleaning unit 1119Y in the rotation direction of the photoconductor 111Y, specifically, downstream of the transfer unit (in this example, the primary transfer roller 133Y) in the rotation direction of the photoconductor 111Y. And disposed upstream of the cleaning means 119Y.
The lubricant supply means 114Y in this example is constituted by a solid lubricant and a lubricant application member made of a brush roller. Specifically, as shown in FIG. 2, the lubricant supply means 114 includes a housing 20, and a lubricant stock 22 made of a solid lubricant having a rectangular parallelepiped shape and housed in the housing 20. A brush roller 21 that abuts on the surface of the photoreceptor 111 and applies the lubricant scraped by rubbing the surface of the lubricant stock 22 to the surface of the photoreceptor 111; and a pressure spring 23 that presses the lubricant stock 22 against the brush roller 21; Consists of. The brush roller 21 has a brush tip in contact with the surface of the photoconductor 111. Further, the brush roller 21 is driven to rotate at a constant speed in the reverse direction to the rotation direction of the photoconductor 111.

The brush roller 21 is formed by, for example, a long woven fabric formed by densely imprinting resin brush fibers such as polypropylene on the peripheral surface of the roller base. The brush roller 21 has a brush fiber thickness of, for example, 3 to 7 denier, a brush fiber bristle length of 2 to 5 mm, a brush fiber electrical resistivity of 1 × 10 ¹⁰ Ω or less, and a brush fiber Young's modulus of 1500. It is preferable that the planting density of brush fibers (number of brush fibers per unit area) is, for example, 50 k to 200 kF / inch ² .about.9800 N / mm ² .

  The pressure spring 23 is used to press the lubricant stock 22 in the direction approaching the photoconductor 111 so that the pressing force of the brush roller 21 against the photoconductor 111 is, for example, 0.5 to 1.0 N.

In the lubricant supply means 114, for example, the brush roller of the lubricant stock 22 is set so that the coating amount per 1 cm ² of the surface of the photoreceptor 111 is 0.5 × 10 ^{−7 to} 1.5 × 10 ⁻⁷ g / cm ^2. The pressing force with respect to 21 and the rotation speed of the brush roller 21 are adjusted.

  As the lubricant, for example, fatty acid metal salts such as zinc oleate, zinc stearate, calcium stearate and the like can be used. Among these, zinc stearate is preferable from the viewpoint of lubricity and spreadability.

[Cleaning means]
The cleaning unit 119Y is a unit that removes toner remaining on the surface of the photoreceptor 111Y. The cleaning means 119Y in this example is constituted by a cleaning blade. As shown in FIG. 2, the cleaning blade includes a support member 31 and a blade member 30 supported on the support member 31 via an adhesive layer (not shown). The blade member 30 is disposed such that the tip thereof faces in the direction opposite to the rotation direction of the photoconductor 111 (counter direction) at the contact portion with the surface of the photoconductor 111.

  The support member 31 is not particularly limited, and a conventionally known member can be used, and examples thereof include those manufactured from rigid metal, elastic metal, plastic, ceramic, and the like. Among these, a rigid metal is preferable.

  As the blade member 30, for example, a multi-layer structure in which a base layer and an edge layer are laminated can be used. Each of the base layer and the edge layer is preferably made of polyurethane. Examples of the polyurethane include those obtained by reacting a polyol, a polyisocyanate, and, if necessary, a crosslinking agent.

[Lubricant removing means]
The lubricant removing unit 116Y is a unit that removes the lubricant adhering to the surface of the photoreceptor 111Y. The lubricant removing unit 116Y is downstream of the cleaning unit 1119Y in the rotational direction of the photoconductor 111Y, specifically, downstream of the cleaning unit 119Y and upstream of the proximity charging unit 113Y in the rotational direction of the photoconductor 111Y. Is arranged.
The lubricant removing means 116Y is preferably means for removing the lubricant by a mechanical action when the removing member contacts the surface of the photoreceptor 111Y. Here, removing the lubricant by a mechanical action means removing the lubricant by mechanically rubbing the surface of the photoreceptor. As the removal member, a brush roller, a foam roller, or the like can be used, and a brush roller is preferable from the viewpoint of removal capability and durability. Specifically, the lubricant removing means 116Y in this example is in contact with the surface of the photoconductor 111Y, and is a removal member made up of a brush roller that is driven to rotate at a constant speed opposite to the rotation direction of the photoconductor 111Y, and a drive mechanism. It consists of.

As the brush roller as the lubricant removing means 116Y, for example, a pile woven fabric in which a bundle of fibers is woven into a base fabric as a pile yarn is made into a ribbon-like fabric, and the brushed surface is turned outward and spiral around the metal shaft. Wound and bonded. The brush roller of this example is formed by forming a long woven fabric formed of resin brush fibers such as polyester at a high density on the peripheral surface of a metal shaft.
The brush bristles are preferably raised straight in the direction perpendicular to the metal shaft, from the viewpoint of removal capability. The yarn used for the brush hair is preferably a filament yarn, and examples of the material include synthetic resins such as 6-nylon, 12-nylon, polyester, acrylic, and vinylon, and metals such as carbon and nickel are used for the purpose of increasing conductivity. It may be kneaded. The thickness of the brush fiber is preferably 3 to 15 denier, and the hair length of the brush fiber is preferably 2 to 5 mm. In addition, by setting the density of the brush fibers in the range of 40,000 to 500,000 fibers / square inch (40 k to 500 kF / inch ² ), the rigidity necessary for removal is secured and the brush hair is sparse. It is possible to prevent the unevenness of the removal of the lubricant without making the lubricant. The electrical resistivity of the brush fiber is preferably 10 ⁷ Ω or less, and the Young's modulus of the brush fiber is preferably 1500 to 9800 N / mm ² . The biting amount of the brush roller with respect to the photosensitive member is preferably 0.5 to 1.5 mm. The rotational speed of the brush roller is, for example, 0.3 to 1.5 in terms of the photoreceptor speed ratio, and may be in the same direction as that of the photoreceptor or in the opposite direction.

In the image forming apparatus 100 of the present invention, as shown in FIG. 2, the lubricant present ratio per unit area of the surface of the photoconductor 111 after the lubricant is supplied by the lubricant supplying means 114 and before the toner is removed by the cleaning means 119. Is A (atom%), and B (atom%) is the lubricant present ratio per unit area of the surface of the photoreceptor 111 after the lubricant is removed by the lubricant removing means 116, the following formulas (1) and (2) Fulfill. That is, in the image forming apparatus 100 of the present invention, the lubricant supply means 114 and the lubricant removal means 116 adjust the amount of lubricant present on the surface of the photoreceptor 111 so as to satisfy the following expressions (1) and (2). Done.
Formula (1): A ≧ 5.0B
Formula (2): B ≦ 0.20
By satisfying both the above formulas (1) and (2), before the toner is removed by the cleaning means 119, the lubricant is sufficiently present on the surface of the photoconductor 111, so that a good toner cleaning property can be obtained. After the removal of the lubricant by the lubricant removing means 116, the lubricant is removed from the surface of the photoreceptor 111. Therefore, in the next image formation, even if charging is performed by the proximity charging method in a high temperature and high humidity environment, the lubricant is deteriorated. Therefore, image defects such as image flow accompanying the image are not caused.

In the measurement of the lubricant presence ratio A, an arbitrary location on the surface of the photoconductor 111 on the rotating photoconductor 111 downstream of the lubricant supply unit 114 and upstream of the cleaning unit 119 can be selected.
Further, in the measurement of the lubricant presence ratio B, an arbitrary location on the surface of the photoreceptor 111 on the downstream side of the lubricant removing means 116 can be selected in the rotating photoreceptor 111, but in the present invention, the lubricant removing means is selected. An arbitrary location on the surface of the photoconductor 111 downstream of 116 and upstream of the proximity charging unit 113 is selected.
Specifically, if the lubricant presence ratio B is in the range of 0.20 atom% or less, it can be said that the lubricant adhering to the surface of the photoreceptor is sufficiently removed.

Here, the lubricant presence ratio refers to the degree of presence of lubricant per unit area of the photoreceptor surface. In the present invention, the abundance ratio of the metal derived from the lubricant (fatty acid metal salt) on the photoreceptor surface measured by X-ray photoelectron spectroscopy (ESCA) is used as an alternative amount. The unit is “atom%”. Selective elements to be detected are (1) elements (C, O, etc.) of the crosslinked polymer constituting the protective layer, (2) metal oxide (eg, Sn), (3) lubricant supplied to the surface of the photoreceptor ( A metal derived from (fatty acid metal salt) (for example, Zn, Al, etc.). For these selected elements, it is necessary to extract all the elements that can be present on the surface of the photoreceptor depending on the type of material constituting the protective layer and the type of lubricant used. In addition, from the viewpoint of detectability, in order to differentiate between the metal derived from the metal oxide contained in the protective layer and the metal derived from the lubricant, select a different type from the metal oxide used and the metal of the lubricant. .
Specifically, only the protective layer is cut out from the photosensitive member at a 5 mm square to obtain a measurement sample. Using the X-ray photoelectron spectrometer “K-Alpha” (manufactured by Thermo Fisher Scientific), the selected elements are quantitatively analyzed under the following measurement conditions, and the surface element concentration is determined from each atomic peak area using the relative sensitivity factor. calculate. Treat the amount of metal detected as an alternative.
-Measurement conditions X-ray: Al monochrome source acceleration: 12 kV, 6 mA
Resolution: 50eV
Beam system: 400 μm
Step size: 0.1eV

  The lubricant presence ratio A can be controlled by the supply method or supply amount by the lubricant supply means. Further, the lubricant presence ratio B can be controlled by the type of the removing member by the lubricant removing means and the contact state of the removing member.

  The intermediate transfer body unit 130 is provided so as to be in contact with the photoreceptors 111Y, 111M, 111C, and 111Bk. The intermediate transfer body unit 130 includes an endless belt-shaped intermediate transfer body 131, primary transfer rollers 133Y, 133M, 133C, and 133Bk disposed in contact with the endless belt-shaped intermediate transfer body 131, and the endless belt-shaped intermediate transfer body. 131 cleaning means 135.

  In this image forming apparatus 100, the toner images formed on the photoconductors 111Y, 111M, 111C, and 111Bk are transferred to the intermediate transfer body 131 by primary transfer rollers (primary transfer means) 133Y, 133M, 133C, and 133Bk. An intermediate transfer method is employed in which each toner image transferred onto the transfer member 131 is transferred to a transfer material P by a secondary transfer roller (secondary transfer means) 217. However, the toner image formed on the photosensitive member is not transferred. A direct transfer method in which the image is directly transferred onto a transfer material by a transfer unit may be employed.

  The endless belt-shaped intermediate transfer member 131 is wound around a plurality of rollers 137A, 137B, 137C, and 137D and is rotatably supported.

  In the image forming apparatus 100, the photosensitive member 111Y, the developing unit 117Y, the lubricant supplying unit 114Y, the cleaning unit 119Y, the lubricant removing unit 116Y, and the like are integrally coupled and are detachably attached to the apparatus main body (image cartridge). Forming unit). Alternatively, the photosensitive member 111Y includes at least one member selected from the group consisting of a proximity charging unit 113Y, an exposure unit 115Y, a developing unit 117Y, a lubricant supply unit 114Y, a lubricant removing unit 116Y, a primary transfer roller 133Y, and a cleaning unit 119Y. It may be a process cartridge (image forming unit) configured integrally.

  The process cartridge 200 includes a casing 201, a photosensitive member 111Y, a proximity charging unit 113Y, a developing unit 117Y, a lubricant supplying unit 114Y, a cleaning unit 119Y, a lubricant removing unit 116Y, and an intermediate transfer body unit 130 accommodated therein. Have. The apparatus main body is provided with support rails 203L and 203R as means for guiding the process cartridge 200 into the apparatus main body. Thereby, the process cartridge 200 can be attached to and detached from the apparatus main body. These process cartridges 200 can be a single image forming unit configured to be detachable from the apparatus main body.

  The sheet feeding / conveying means 150 is provided so that the transfer material P in the sheet feeding cassette 211 can be conveyed to the secondary transfer roller 217 via a plurality of intermediate rollers 213A, 213B, 213C, 213D and a registration roller 215.

  The fixing unit 170 fixes the color image transferred by the secondary transfer roller 217. The paper discharge roller 219 is provided so as to be placed on the paper discharge tray 221 with the transfer material P that has been subjected to the fixing process interposed therebetween.

  In the image forming apparatus 100 configured as described above, a toner image is formed by the image forming units 110Y, 110M, 110C, and 110Bk. Specifically, the surfaces of the photoconductors 111Y, 111M, 111C, and 111Bk are discharged and charged negatively by the proximity charging units 113Y, 113M, 113C, and 113Bk. Next, the surface of the photoconductors 111Y, 111M, 111C, and 111Bk is exposed based on the image signal by the exposure means 115Y, 115M, 115C, and 115Bk, and an electrostatic latent image is formed. Next, with the developing units 117Y, 117M, 117C, and 117Bk, toner is applied to the surface of the photoreceptors 111Y, 111M, 111C, and 111Bk and developed to form a toner image.

  Next, primary transfer rollers (primary transfer means) 133Y, 133M, 133C, and 133Bk are brought into contact with the rotating endless belt-shaped intermediate transfer member 131. As a result, the toner images of the respective colors formed on the photoreceptors 111Y, 111M, 111C, and 111Bk are sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 131 to transfer the color image (primary transfer). . During the image forming process, the primary transfer roller 133Bk is always in contact with the photoreceptor 111Bk. On the other hand, the other primary transfer rollers 133Y, 133M, and 133C are in contact with the corresponding photoreceptors 111Y, 111M, and 111C, respectively, only during color image formation.

  Then, after separating the primary transfer rollers 133Y, 133M, 133C, and 133Bk and the endless belt-shaped intermediate transfer body 131, the lubricant supply means 114Y, 114M, 114C, and 114Bk are applied to the surfaces of the photoreceptors 111Y, 111M, 111C, and 111Bk. Supply lubricant. Thereafter, the toner remaining on the surfaces of the photoconductors 111Y, 111M, 111C, and 111Bk is removed by the cleaning units 119Y, 119M, 119C, and 119Bk. Then, the lubricant remaining on the surfaces of the photoreceptors 111Y, 111M, 111C, and 111Bk is removed by the lubricant removing means 116Y, 116M, 116C, and 116Bk. Thereafter, in preparation for the next image formation, the surfaces of the photoconductors 111Y, 111M, 111C, and 111Bk are neutralized by a neutralizing unit (not shown) as necessary, and then negatively charged by the proximity charging units 113Y, 113M, 113C, and 113Bk. Charge.

  On the other hand, a transfer material P (for example, a support for carrying a final image such as plain paper or a transparent sheet) accommodated in a paper feed cassette 211 is fed by a paper feed / conveying means 150 and a plurality of intermediate rollers 213A and 213B. 213C, 213D, and registration rollers 215, and then conveyed to a secondary transfer roller (secondary transfer means) 217. Then, the secondary transfer roller 217 is brought into contact with the rotating endless belt-shaped intermediate transfer body 131 to transfer the color image on the transfer material P in a lump (secondary transfer). The secondary transfer roller 217 contacts the endless belt-shaped intermediate transfer body 131 only when performing secondary transfer on the transfer material P. Thereafter, the transfer material P on which the color images are collectively transferred is separated at a portion where the curvature of the endless belt-shaped intermediate transfer body 131 is high.

  The transfer material P onto which the color images have been transferred in this way is fixed by the fixing unit 170 and then sandwiched by the paper discharge roller 219 and placed on the paper discharge tray 221 outside the apparatus. Further, after separating the transfer material P onto which the color image has been collectively transferred from the endless belt-shaped intermediate transfer body 131, the cleaning unit 135 removes residual toner on the endless belt-shaped intermediate transfer body 131.

  As described above, according to the image forming apparatus 100 of the present invention, the lubricant presence ratio per unit of the surface of the photoreceptor after the supply of the lubricant by the lubricant supply unit 114 and before the removal of the toner by the cleaning unit 119 is A (atom%). When the lubricant present ratio per unit on the surface of the photoreceptor after removal of the lubricant by the lubricant removing means 116 is B (atom%), it is good when A ≧ 5.0B and B ≦ 0.20 are satisfied. In addition to having a good toner cleaning property, it is possible to suppress the occurrence of image flow in a high temperature and high humidity environment.

〔toner〕
The toner used in the image forming apparatus of the present invention is not particularly limited, and includes toner particles containing a binder resin and a colorant. The toner particles may include other components such as a release agent as desired. May be contained.
The toner particles constituting the toner preferably have a volume average particle diameter of 2 to 8 μm from the viewpoint of achieving high image quality.

  The method for producing the toner is not particularly limited. For example, a known pulverization method, a wet melt spheronization method prepared in a dispersion medium, suspension polymerization, dispersion polymerization, emulsion polymerization aggregation method and the like are known. And the like.

  In addition, an appropriate amount of inorganic fine particles such as silica and titania having an average particle diameter of about 10 to 300 nm and an abrasive of about 0.2 to 3 μm can be externally added to the toner particles as external additives.

The toner can be used as a magnetic or nonmagnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
In the case where the toner is used as a two-component developer, the carrier may be a conventionally known material such as a ferromagnetic metal such as iron, an alloy such as ferromagnetic metal and aluminum and lead, and a compound of ferromagnetic metal such as ferrite and magnetite. In particular, ferrite is preferable.

(Image forming method)
The image forming method of the present invention can be executed using the image forming apparatus of the present invention. Specifically, a proximity charging step of charging the surface of a photoreceptor having a protective layer containing a crosslinked polymer obtained by curing a polymerizable compound by a proximity charging method, and a photoreceptor charged by the proximity charging step An exposure step for exposing the photosensitive member, a developing step for supplying toner to the photoconductor exposed by the exposure step to form a toner image, a transfer step for transferring the toner image formed on the photoconductor, and the surface of the photoconductor A lubricant supplying step for supplying the lubricant to the surface, a cleaning step for removing the toner remaining on the surface of the photoconductor, and a lubricant removing step for removing the lubricant from the surface of the photoconductor. Later, before the cleaning step, the lubricant removal step is performed after the cleaning step and before the proximity charging step. In the image forming method of the present invention, the ratio of the lubricant present per unit area of the photoreceptor surface after the lubricant supplying step and before the cleaning step is A (atom%), and the surface of the photoreceptor surface after the lubricant removing step is used. When the lubricant presence ratio per unit area is B (atom%), the above formulas (1) and (2) are satisfied. That is, in the image forming method of the present invention, the amount of lubricant present on the photoreceptor surface is adjusted so as to satisfy the above formulas (1) and (2) in the lubricant supply step and the lubricant removal step.

In the lubricant supply step of the image forming method of the present invention, the lubricant may be supplied to the photoreceptor by the lubricant supply means as in the image forming apparatus shown in FIG. The lubricant may be supplied to the photoreceptor by the action of a developing electric field formed in the developing step.
The fine powder lubricant externally added to the toner is not particularly limited as long as it has lubricity and cleavage, but for example, zinc stearate can be used. The number average primary particle size of the lubricant is preferably 1 to 20 μm, for example. Further, the lubricant is preferably added at a ratio of 0.01 to 0.3% by mass with respect to the toner so as not to affect the chargeability of the toner.

  According to the image forming method of the present invention, the ratio of the lubricant per unit of the photoreceptor surface after the lubricant supplying process and before the cleaning process is A (atom%), and the surface of the photoreceptor surface after the lubricant removing process is used. When the ratio of lubricant per unit is B (atom%), satisfying A ≧ 5.0B and B ≦ 0.20, the toner has a good toner cleaning property and is imaged in a high temperature and high humidity environment. Flow generation can be suppressed.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example. In the following, “part” means “part by mass”.

[Photosensitive body preparation example 1]
The surface of an aluminum cylinder having a diameter of 60 mm was cut to prepare a conductive support [1] having a fine and rough surface.

(Formation of intermediate layer)
A dispersion having the following composition was diluted twice with the same solvent as described below, and allowed to stand overnight, followed by filtration (filter; using a lymesh 5 μm filter manufactured by Nihon Pall Co., Ltd.) to prepare an intermediate layer forming coating solution [1]. .
Binder resin: Polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) 1 part Metal oxide particles: Titanium oxide “SMT500SAS” (manufactured by Teica) 3 parts Solvent: Methanol 10 parts Batch using a sand mill as a disperser for 10 hours Was distributed.
An intermediate layer [1] having a dry film thickness of 2 μm was formed on the conductive support [1] using the intermediate layer forming coating solution [1] by dip coating.

(Formation of charge generation layer)
Charge generation material: 20 parts of the following pigment (CG-1), binder resin: 10 parts of polyvinyl butyral resin “# 6000-C” (manufactured by Denki Kagaku Kogyo), solvent: 700 parts of t-butyl acetate, solvent: 4-methoxy 300 parts of -4-methyl-2-pentanone was mixed and dispersed for 10 hours using a sand mill to prepare a coating solution [1] for forming a charge generation layer. This charge generation layer forming coating solution [1] was applied onto the intermediate layer [1] by a dip coating method to form a charge generation layer [1] having a dry film thickness of 0.3 μm.

<Synthesis of Pigment (CG-1)>
(1) Synthesis of amorphous titanyl phthalocyanine 1,3-diiminoisoindoline; 29.2 parts are dispersed in 200 parts of o-dichlorobenzene, and titanium tetra-n-butoxide; 20.4 parts are added under a nitrogen atmosphere. For 5 hours at 150-160 ° C. After allowing to cool, the precipitated crystals were filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol, and dried to obtain 26.2 parts (yield 91%) of crude titanyl phthalocyanine.
Next, the crude titanyl phthalocyanine was dissolved by stirring for 1 hour in 250 parts of concentrated sulfuric acid at 5 ° C. or less, and this was poured into 5000 parts of water at 20 ° C. The precipitated crystals were filtered and sufficiently washed with water to obtain 225 parts of a wet paste product.
This wet paste product was frozen in a freezer, thawed again, filtered and dried to obtain 24.8 parts of amorphous titanyl phthalocyanine (yield 86%).

(2) Synthesis of (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine (CG-1) 10.0 parts of the above amorphous titanyl phthalocyanine and (2R, 3R) -2,3-butanediol 94 parts (0.6 equivalent ratio) (equivalent ratio is equivalent ratio to titanyl phthalocyanine, hereinafter the same) was mixed in 200 parts of orthochlorobenzene (ODB) and stirred at 60 to 70 ° C. for 6.0 hours. After standing overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The crystals after filtration were washed with methanol (a pigment containing (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine). CG-1: 10.3 parts were obtained. In the X-ray diffraction spectrum of the pigment (CG-1), there are clear peaks at 8.3 °, 24.7 °, 25.1 °, and 26.5 °. There is a peak in the 576 and 648 in the mass spectra, O-Ti-O both absorption appears Ti = O near 970 cm ^-1, around 630 cm ^-1 in the IR spectrum. In addition, since thermal analysis (TG) has a mass loss of about 7% at 390 to 410 ° C., a 1: 1 adduct and a non-adduct (addition) of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol (Not) presumed to be a mixture of titanyl phthalocyanine.
It was 31.2 m < ² > / g when the BET specific surface area of the obtained pigment (CG-1) was measured with the flow type specific surface area automatic measuring apparatus (Micrometrics flow soap type: Shimadzu Corporation).

(Formation of charge transport layer)
Charge transport material: 225 parts of the following compound A, binder resin: 300 parts of polycarbonate resin “Z300” (Mitsubishi Gas Chemical Co., Ltd.), antioxidant: “Irganox 1010” (manufactured by Ciba Geigy Japan), solvent: THF (tetrahydrofuran) 1600 Part, solvent: 400 parts of toluene and 1 part of silicone oil “KF-50” (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and dissolved to prepare a coating solution [1] for forming a charge transport layer.
The charge transport layer forming coating solution [1] was applied onto the charge generation layer [1] using a circular slide hopper coating apparatus to form a charge transport layer [1] having a dry film thickness of 20 μm.

(Formation of protective layer)
(1) Preparation of metal oxide fine particles 100 parts of tin oxide (number average primary particle size: 20 nm), 30 parts of the exemplified compound (S-13) as a surface treatment agent, toluene / isopropyl alcohol = 1/1 (mass ratio) A mixed solution of 300 parts of the above mixed solvent was put in a sand mill together with zirconia beads and stirred at about 40 ° C. at a rotational speed of 1500 rpm. Further, the above treated mixture was taken out, put into a Henschel mixer and stirred at a rotational speed of 1500 rpm for 15 minutes. Then, the surface treatment of the tin oxide by the compound which has a radically polymerizable functional group was completed by drying at 120 degreeC for 3 hours, and the surface-treated tin oxide was obtained. This is designated as metal oxide fine particles [1]. The surface of the tin oxide particles was coated with the exemplified compound (S-13) by the surface treatment with the compound having the radical polymerizable functional group.

(2) Formation of protective layer 100 parts of metal oxide fine particles [1], polymerizable compound: 100 parts of the exemplified compound (M1), solvent: 320 parts of sec-butanol, solvent: 80 parts of THF (tetrahydrofuran) under light shielding. After mixing and dispersing for 5 hours using a sand mill as a disperser, 10 parts of a polymerization initiator: “Irgacure” (manufactured by BASF Japan Ltd.) is added, and the mixture is stirred and dissolved under light shielding to form a protective layer forming coating solution. [1] was prepared. The protective layer-forming coating solution [1] was applied onto the charge transport layer [1] using a circular slide hopper coating device to form a coating film. Then, this coating film was dried at room temperature for 15 minutes, and the separation distance between the light source and the coating film was set to 10 mm under a nitrogen flow using a xenon lamp, and irradiated with ultraviolet rays at a lamp output of 1 kW for 1 minute to dry. A protective layer [1] having a thickness of 3.0 μm was formed to produce a photoreceptor [1]. The universal hardness of the protective layer in this photoreceptor [1] was 280.

[Photoconductor Preparation Example 2]
Photoreceptor [2] was produced in the same manner as in the formation of the protective layer in Production Example 1 of the photoreceptor except that the polymerizable compound used was changed to the exemplified compound (M8). The universal hardness of the protective layer in this photoreceptor [2] was 200.

[Photoconductor Preparation Example 3]
In the formation of the protective layer in Preparation Example 1 of the photoreceptor, the light source used after drying the coating film was changed to a metal halide lamp, the separation distance between the light source and the coating film was changed to 100 mm, and the lamp output was changed to 4 kW. A photoreceptor [3] was prepared in the same manner as above. The universal hardness of the protective layer in this photoreceptor [3] was 400.

[Photoconductor Preparation Example 4]
Photoreceptor [4] was produced in the same manner as in the formation of the protective layer in Production Example 1 of the photoreceptor, except that the polymerizable compound used was changed to the exemplified compound (M11). The universal hardness of the protective layer in this photoreceptor [4] was 550.

<Example 1>
The image forming apparatus “bizhub C6500” (manufactured by Konica Minolta Co., Ltd.) is loaded with a predetermined developer and the photoreceptor [1], and the image forming unit is modified to a contact roller charging method so that charging by proximity charging is performed. Further, a lubricant removing means having the following specifications was installed on the downstream side of the cleaning means. This lubricant removing means was set to the following condition [1]. This apparatus is provided with a solid lubricant made of zinc stearate and a brush roller as lubricant supply means. The following evaluation was performed using this evaluation machine. The results are shown in Table 1.

-Specifications of lubricant removal means-
As the lubricant removing means, a removing member made of a straight hair type brush roller was used. The filament yarn is a carbon-containing nylon fiber “SA-7” (manufactured by Toray Industries, Inc.), a ribbon having a brush fiber thickness of 10 denier, a brush fiber planting density of 75 kF / inch ² , and a brush fiber bristle length of 3.0 mm. The dough was spirally wound around a metal shaft (SUM22) having an outer diameter of 6 mm.
Condition [1]: The brush roller was installed so that the biting amount was 0.5 mm with respect to the photoconductor, and rotated at a peripheral speed ratio of 0.6 in the direction opposite to the rotation direction of the photoconductor. The brush roller was grounded via a metal shaft.
Condition [2]: The brush roller was installed so that the biting amount was 0.5 mm with respect to the photoreceptor, and was rotated at a peripheral speed ratio of 1.2 in the same direction as the rotation direction of the photoreceptor. The brush roller was grounded via a metal shaft.
Condition [3]: The brush roller was installed with respect to the photosensitive member so that the biting amount was 0.25 mm, and rotated at a peripheral speed ratio of 1.2 in the same direction as the rotational direction of the photosensitive member. The brush roller was grounded via a metal shaft.

  In this evaluation machine, the lubricant presence ratio A per unit area of the surface of the photoreceptor after the lubricant is supplied by the lubricant supplying means and before the toner is removed by the cleaning means is 2 (atom%), and the lubricant is removed by the lubricant removing means. The lubricant existing ratio B per unit area of the photoreceptor surface after the removal was 0.1 (atom%). The lubricant abundance ratio was measured by using an X-ray photoelectron spectrometer “K-Alpha” (manufactured by Thermo Fisher Scientific) and quantitatively analyzing zinc, tin, silicon, carbon, oxygen, and nitrogen as selective elements. The measured amount of zinc was used as an alternative amount. Hereinafter, the measurement of the lubricant presence ratio in Examples 2 to 7 and Comparative Examples 1 to 4 is the same.

(1) Image flow evaluation In a high-temperature and high-humidity environment (temperature of 30 ° C., humidity of 85% RH), after 2000 character charts corresponding to a printing rate of 5% were printed continuously, and then one halftone image was printed The power was turned off and left for 8 hours, and then turned on to print 20 A3 halftone images continuously.
The image flow was evaluated by the number of sheets when the halftone image was restored to the level of the halftone image printed before leaving. The case where it recovered within the third sheet was evaluated as “◎”, the case where it recovered within the seventh sheet was “◯”, and the case where it recovered after the eighth sheet was evaluated as “×”. Note that the seventh sheet is based on the seventh sheet because the rotation speed of the photoconductor for image stabilization performed when the apparatus is started up is equivalent to the seventh sheet printing of A3 paper. This is because it is considered that image deterioration due to image flow does not occur from the first printing.

(2) Evaluation of photoconductor depletion amount After printing 100,000 sheets of a character chart corresponding to a printing rate of 5% in a normal temperature and normal humidity environment (temperature: 25 ° C., humidity: 50% RH), the protective layer film of the photoconductor The thickness was measured. The film thickness was measured using an eddy current film thickness measuring machine “Fischer Scope MMS PC” (manufactured by Fisher Instruments). The case where the amount of wear of the protective layer is within 0.3 μm is “、”, the case where it is larger than 0.3 μm and within 0.6 μm is “◯”, and the case where it is larger than 0.6 μm and within 1.0 μm. The case where Δ was larger than 1.0 μm was evaluated as “X”.

(3) Evaluation of toner cleaning property In a low-temperature and low-humidity environment (temperature: 10 ° C., humidity: 15% RH), the toner cleaning property was confirmed using the photoconductor and the cleaning blade after the evaluation of (2) depletion amount. For the measurement of the cleaning property, an external driving machine based on the image forming apparatus “bizhub C6500” was used, and a photosensitive unit with a cleaning blade set at a contact linear pressure of 15 N / m and an effective contact angle of 11 ° was prepared and driven. In this state, an entire band with a toner amount of 1 g / m ² was output for one revolution (94 mm) of the photosensitive member, and the presence or absence of toner wiping remaining after the belt passed the cleaning blade for one revolution was judged. The case where no wiping residue was left on the entire surface was evaluated as “◯”, the case where wiping residue was generated only on the blade chipping portion was evaluated as “Δ”, and the case where wiping residue was generated on the surface was evaluated as “X”.

<Example 2>
In Example 1, the above evaluation was performed in the same manner except that the lubricant removing means was set to the above condition [2].

<Example 3>
In Example 1, the above-described evaluation was performed in the same manner as in Example 1 except that the lubricant supply means was set not to start and the following developer [1] was used.

[Preparation of developer [1]]
(1) Addition of external additive to toner particles Toner particles (volume-based average particle diameter: 5.9 μm, glass transition point (Tg): 31 ° C., average circularity: 0.960) 0.75 parts by mass of fine particles ("RX-200" fumed silica HMDS treatment, number average particle size 12 nm; manufactured by Nippon Aerosil Co., Ltd.), silica HMDS treatment by spherical silica fine particles ("X-24 9600" sol-gel method), number average particle size 80 nm; 1.50 parts by mass of Shin-Etsu Chemical Co., Ltd., fatty acid metal salt fine particles imparting a lubricity function, zinc stearate particles (“ZnSt-S”; NOF Corporation volume standard average particle size 10.0 μm) 0.10 parts by mass of adjustment, calcium titanate particles (“TC110” number average primary particle size 300 nm) as a metal oxide fine particle having a high polishing effect 0.5 parts by mass of Ton Kogyo Co., Ltd. was added, and the mixture was mixed for 15 minutes at a stirring blade peripheral speed of 40 m / sec and a processing temperature of 30 ° C. using a “Heschel mixer“ FM10B ”(Mitsui Miike Chemical Co., Ltd.) Thereafter, coarse particles were removed using a sieve having an opening of 90 μm to prepare toner [1].
(2) Preparation of Developer A toner carrier having a volume-based median diameter of 33 μm coated with a copolymer resin of cyclohexyl methacrylate and methyl methacrylate (monomer ratio = 1: 1) to the toner [1] is used. Developer [1] was produced by mixing so as to be 6.0% by mass.

<Example 4>
In Example 2, the above evaluation was performed in the same manner as in Example 2 except that the lubricant supply means was set not to start and the developer [1] was used.

<Example 5>
The above-described evaluation was performed in the same manner as in Example 2 except that the photoreceptor [1] was changed to the photoreceptor [2].

<Example 6>
The above evaluation was performed in the same manner as in Example 1 except that the photoconductor [1] was changed to the photoconductor [3].

<Example 7>
The above evaluation was performed in the same manner as in Example 1 except that the photoconductor [1] was changed to the photoconductor [4].

<Comparative Example 1>
In Example 1, the above evaluation was performed in the same manner except that the lubricant removing means was set to the above condition [3].

<Comparative example 2>
In Example 3, the above evaluation was performed in the same manner except that the lubricant removing means was set to the above condition [3].

<Comparative Example 3>
In Example 1, the above evaluation was performed in the same manner except that no lubricant removing means was installed.

<Comparative Example 4>
In Example 3, the evaluation was performed in the same manner except that no lubricant removing means was installed.

<Comparative Example 5>
In Example 3, the above evaluation was performed in the same manner except that no lubricant removing means was installed and no lubricant was added in the developer [1].

20 Housing 21 Brush roller 22 Lubricant stock 23 Pressure spring 30 Blade member 31 Support member 100 Image forming apparatus 110Y, 110M, 110C, 110Bk Image forming unit 111, 111Y, 111M, 111C, 111Bk Photosensitive member 113, 113Y, 113M, 113C, 113Bk Proximity charging means 114, 114Y, 114M, 114C, 114Bk Lubricant supply means 115Y, 115M, 115C, 115Bk Exposure means 116, 116Y, 116M, 116C, 116Bk Lubricant removal means 117Y, 117M, 117C, 117Bk Developing means 119, 119Y, 119M, 119C, 119Bk Cleaning means 130 Intermediate transfer member unit 131 Endless belt-like intermediate transfer member 133Y, 133M, 133C, 133Bk A transfer roller (transfer means)
135 Cleaning means 137A, 137B, 137C, 137D Roller 150 Paper feed conveyance means 170 Fixing means 200 Process cartridge 201 Housing 203R, 203L Support rail 211 Paper feed cassette 213A, 213B, 213C, 213D Intermediate roller 215 Registration roller 217 Secondary transfer Roller (transfer means)
219 Paper discharge roller 221 Paper discharge tray P Transfer material SC Document image reading device

Claims (6)

A photosensitive member having a protective layer containing a cross-linked polymer obtained by curing a polymerizable compound; a proximity charging unit that charges the surface of the photosensitive member by a proximity charging method; and a photosensitive member charged by the proximity charging unit. An exposure unit that exposes the body, a developing unit that supplies toner to the photoconductor exposed by the exposure unit to form a toner image, a transfer unit that transfers the toner image formed on the photoconductor, Image forming comprising: a lubricant supplying means for supplying a lubricant to the surface of the photoreceptor; a cleaning means for removing toner remaining on the surface of the photoreceptor; and a lubricant removing means for removing the lubricant from the surface of the photoreceptor. A device,
The lubricant supply means is disposed upstream of the cleaning means in the rotation direction of the photoconductor,
The lubricant removing means is disposed on the downstream side of the cleaning means in the rotation direction of the photoconductor and is disposed in contact with the surface of the photoconductor , and mechanically rubs the surface of the photoconductor to remove the lubricant. Having a brush roller to remove,
After supplying the lubricant by the lubricant supplying means, the ratio of the lubricant per unit area on the surface of the photoreceptor before the toner removal by the cleaning means is A (atom%), and after removing the lubricant by the lubricant removing means. An image forming apparatus, wherein A ≧ 5.0B and B ≦ 0.20 are satisfied, where B (atom%) is a lubricant present ratio per unit area on the surface of the photoreceptor. The image forming apparatus according to claim 1, wherein the lubricant contains zinc stearate . The image forming apparatus according to claim 1 , wherein the lubricant supply unit includes a solid lubricant and a lubricant application member .   A proximity charging step of charging the surface of a photoreceptor having a protective layer containing a crosslinked polymer obtained by curing a polymerizable compound by a proximity charging method, and exposure for exposing the photoreceptor charged by the proximity charging step A developing step for supplying toner to the photoconductor exposed by the exposure step to form a toner image, a transfer step for transferring the toner image formed on the photoconductor, and a surface of the photoconductor An image forming method comprising: a lubricant supplying step for supplying a lubricant; a cleaning step for removing toner remaining on the surface of the photoconductor; and a lubricant removing step for removing the lubricant from the surface of the photoconductor.
  The lubricant supply process is performed before the cleaning process,
  The lubricant removing step is performed after the cleaning step, and a brush roller is placed in contact with the surface of the photoconductor, and the surface of the photoconductor is mechanically rubbed by the brush roller to remove the lubricant. Is,
  A (atom%) is the lubricant present ratio per unit area of the photoreceptor surface before the cleaning process after the lubricant supplying process, and the lubricant per unit area of the photoreceptor surface after the lubricant removing process. An image forming method, wherein A ≧ 5.0B and B ≦ 0.20 are satisfied when the existence ratio is B (atom%). 5. The lubricant supply step according to claim 4, wherein in the lubricant supply step, a fine powder lubricant externally added to the toner is supplied to the photoreceptor by the action of a developing electric field formed in the development step. Image forming method. The image forming method according to claim 4, wherein the lubricant contains zinc stearate.

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