JP2006243331A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method in which image deletion on a high hardness photoreceptor is prevented and good cleaning performance is maintained and by which a high durability and high quality image of well fixed toner can be output. <P>SOLUTION: In a developer used, there are contained spherical or amorphous strontium titanate inorganic powder having a primary particle diameter of 0.60 μm to a number average particle diameter of toner in the developer, and strontium titanate in which primary particles have a cubic particle shape and/or a cuboidal particle shape and an average particle diameter of 0.030-0.300 μm. The content of the strontium titanate in residual toner after transfer is 5.0-20.0 mass%, and a content of the strontium titanate inorganic powder in toner on a transfer material after transfer is 0.4-1.8 mass%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic image forming method. More specifically, the electrophotographic photosensitive member is charged, an electrostatic latent image is formed on the charged surface of the photosensitive member, information is written, and the electrostatic latent image on the photosensitive member is converted into a toner image by the developer carried on the developer carrying member. And a toner image on a photoconductor is transferred to a transfer material, and then the toner image is fixed on the transfer material by a fixing device.

  In an image forming method used for an electrophotographic apparatus, an electrostatic recording apparatus, and the like, various methods are known as a method for forming a latent image on a photosensitive member such as an electrophotographic photosensitive member or an electrostatic recording dielectric. For example, in electrophotography, an electrical latent image is formed by uniformly charging a photoconductor using a photoconductive material as a latent photoconductor to the required polarity and potential, and then performing image pattern exposure. In general, the toner is developed and visualized, and this is transferred and fixed to a transfer medium such as paper.

  Conventionally, in this type of image forming method, by providing a protective layer on the outermost surface layer, an electrophotographic photosensitive member that has excellent durability against wear and scratches and can maintain high quality image quality. The thing using a body is proposed (for example, refer to patent documents 1 and patent documents 2).

  In particular, a photoreceptor having a protective layer made of a curable resin can increase elasticity while maintaining a large HU (Universal Hardness Value). This type of photoreceptor having both rigidity and elasticity is strong against abrasion and has high durability. In such an image forming method using a photoconductor, since it is resistant to rubbing with a cleaning blade or the like, the durable life and potential change of the photoconductor can be suppressed, and stable image output performance can be obtained over a long period of time.

As other highly durable photoreceptors, amorphous silicon (a-Si) photoreceptors have been frequently used. This amorphous silicon photoreceptor has an extremely hard Vickers hardness of 500 or more (500 Kg / m ² or more, JIS standard), and is excellent in durability, heat resistance, and environmental stability. For this reason, it has become indispensable in a high-speed machine that requires particularly high reliability (for example, see Patent Document 3).

  However, in the case of the electrophotographic photosensitive member having improved wear resistance as described above, since the amount of abrasion of the photosensitive member itself is small, the discharge product generated in the primary charging process and adhered to the surface of the photosensitive member is, for example, cleaned. It is difficult to remove with a scraping force with a blade or the like, and problems such as image flow in a high-humidity environment, damage to the cleaning blade, and drooling occur.

  As a method for solving these problems, it is possible to improve these problems by adding particles having an abrasive action to the toner and stripping off the charged products adhering to the surface of the photoreceptor as described above. It has been. However, conventionally used abrasive particles have a large particle size and a broad particle size distribution, so it is necessary to add a large amount to the toner in order to uniformly polish the surface of the photoreceptor. Problems such as scattering, reversal fogging, and accumulation of abrasive particles were likely to occur. As an improvement of this point, strontium titanate with a small particle size and reduced looseness is proposed, and there is also an inorganic fine powder that has an excellent polishing effect when added in a small amount (for example, see Patent Document 4). ).

  This technology not only reduces the local bias on the surface of the photoconductor due to the polishing action, but also a photoconductor, as compared to the method of rubbing the surface of the photoconductor using a separately prepared abrasive such as a web or a rubber roller. It has the advantage that surface deterioration can be suppressed.

JP 2000-66425 A JP 2000-206715 A JP-A-60-67951 Japanese Patent Laid-Open No. 10-10770

  However, the above-described image forming method has the following problems.

  Some strontium titanates externally added to the toner move to the transfer medium together with the toner when transferred from the photoreceptor to the transfer medium. In particular, the small diameter strontium titanate has a high probability of moving with the toner.

  For this reason, particularly when the amount of strontium titanate is small, depending on the transfer conditions, the absolute amount of strontium titanate supplied to the photosensitive member cleaning means as the transfer residual toner may be insufficient and a sufficient effect may not be obtained.

  In addition, when strontium titanate is transferred to the transfer medium along with the toner and abundantly exists on the transfer medium, strontium titanate is a factor that impairs the performance of the fixing device when sent to the fixing device. Become. In other words, when strontium titanate with a small diameter adheres to the toner, the fixing pressure and heat transfer to the toner may be hindered, or the adhesion to the transfer medium may be impaired. Become.

  An object of the present invention is to provide an image capable of outputting a good image without impairing the fixing performance while maintaining excellent durability without image flow, destruction of a cleaning member and toner fusion on a high-hardness photoconductor over a long period of time. It is to provide a forming method.

  As a result of intensive studies, the inventors of the present invention have solved the above problems by rubbing the surface of a high-hardness photosensitive member with an abrasive, and appropriately combining the particle size and shape of the abrasive particles. It has been found that by appropriately defining the movement destination and movement amount, image flow can be prevented and image formation with high toner fixing performance can be performed while maintaining good cleaning performance.

  Specifically, the above object can be achieved by using the following image forming method.

(1) The surface of the photoconductor is charged, an electrostatic latent image is formed on the photoconductor, the developer is carried on the developer carrier, and the developer is carried from the developer carrier to the surface of the photoconductor. In the image forming method in which the latent image is developed, the developed toner image is transferred to a transfer material, and the developer on the transfer material is fixed by a fixing unit.
In the developer, spherical or irregular strontium titanate inorganic powder having a primary particle size of 0.60 μm or more and not more than the number average particle size of the toner, and cubic particles and / or cuboid particles of primary particles Containing strontium titanate having a shape and an average primary particle size of 0.030 to 0.300 μm,
The content of strontium titanate in the transfer residual toner is 5.0% by mass or more and 20.0% by mass or less, and the content of strontium titanate inorganic powder in the toner on the transfer material after the transfer is 0. 0%. An image forming method, wherein the content is 4% by mass or more and 1.8% by mass or less.

(2) The photosensitive member has a photosensitive layer on a conductive support, and the surface of the photosensitive layer is subjected to a hardness test using a Vickers square pyramid diamond indenter under an environment of 25 ° C. and 50% humidity to obtain a maximum load. It has an electrophotographic photosensitive member surface whose HU (universal hardness value) when pressed at 6 mN is 150 N / mm ² or more and 220 N / mm ² or less and whose elastic deformation rate Wo is 44% or more and 65% or less. An image forming method.

(3) The developer carrying member has at least a substrate and a resin coating layer provided on the substrate, and the resin coating layer has a number average particle diameter of 0.3 to 20 μm and a true density of 3 g / cm ³ or less. An image forming method comprising: a spherical carbon particle, wherein Ra of the surface irregularity of the resin coating layer is 0.3 to 0.9 μm.

  (4) An image forming method, wherein each of the strontium titanate inorganic powders is charged to the opposite polarity to the toner.

  (5) An image forming method comprising a mode in which a reverse bias is applied during non-image formation to develop a reversal toner on a photoconductor, and the reversal toner is provided on the photoconductor.

(6) The content of the spherical or amorphous strontium titanate inorganic powder in the transfer residual toner is α mass%, the primary particles are cubic and / or cuboidal particles, and the primary particles are titanium. When the content of strontium acid is β mass%, the following formula: 0.1 ≦ β / α ≦ 0.5
An image forming method characterized by satisfying

(7) The image forming method, wherein the photoconductor has a photoconductive layer composed of a non-single crystal material based on silicon atoms, and has a Vickers hardness (JIS standard) of 500 kg / m ² or more. .

  According to the present invention, when refreshing the surface of the photosensitive member by rubbing the surface of the photosensitive member having a high hardness with an abrasive having a small particle size, two or more kinds of abrasives having different shapes and particle sizes are used and the transfer residue is maintained. By defining the amount of abrasive particles on the toner and transfer medium, it is possible to form images with good fixing performance and high image quality and long life while preventing image flow, destruction of the cleaning member, and toner fusion. it can.

<Image forming process>
FIG. 1 shows an example of an image forming apparatus according to the present invention. FIG. 2 is a longitudinal sectional view showing a schematic configuration of a digital copying machine. The copying machine shown in the figure includes a drum-type electrophotographic photosensitive member 101 as a photosensitive member. The photosensitive member 101 is rotationally driven in the direction of an arrow by a driving unit (not shown). Around the photosensitive member 101, a charging roller 102, which is a primary charging unit, an exposure unit 103, a developing unit (developing unit) 104, and a transfer charging unit (transfer unit) 105 are arranged almost sequentially along the rotation direction. ing. Further, a fixing device 106 is disposed on the downstream side (left side in the figure) of the transfer charger 105 in the conveyance direction (arrow direction) of the transfer material 111. The surface of the photoreceptor 101 is uniformly charged by the primary charger 102. Next, image exposure is performed by the laser beam emitted from the exposure means 103, the electric charge of the laser beam irradiated portion is removed, and an electrostatic latent image is formed. The electrostatic latent image on the photoconductor 101 is developed with the charged toner of the developing device 104. The developed toner image on the photoreceptor 101 is transferred by the transfer charger 105 to the transfer material 111 conveyed in the direction of the arrow. After the toner image is transferred, the transfer material 111 is conveyed to a fixing device 106 where the toner image is fixed on the surface by being heated and pressurized. The untransferred toner remaining on the photosensitive member after the transfer is collected and removed by an elastic cleaning blade in contact with the counter of the drum of the cleaning device 107. The cleaning device 107 is means for collecting and cleaning the transfer residual toner remaining on the photoconductor after the toner transfer. For example, it is performed by bringing an elastic blade mainly made of polyurethane rubber into contact with the rotation of the photosensitive member with a counter as shown in FIG. The toner and lubricant scraped off by the cleaning blade are received by the scooping sheet and sent to the waste toner box by a toner feed blade, a brush roller, a screw and the like.

<Abrasive particles>
As a result of intensive studies by the inventor, strontium titanate inorganic fine powder having an average primary particle size of 0.030 to 0.300 μm (30 to 300 nm) and a cubic or rectangular parallelepiped shape. (Hereinafter, cubic strontium titanate) is adhered to the surface of the photoconductor, and interposed between the contact members and rubbed to remove deposits such as discharge products, paper dust and toner on the high hardness photoconductor. And found that it is possible to prevent image flow and clean blade missing.

  The cubic strontium titanate used in the present invention preferably has an average primary particle size of 30 nm to 300 nm. If the average particle size is less than 30 nm, the polishing effect in the cleaner portion is insufficient, while if it exceeds 300 nm, scratches are likely to occur when the photosensitive member is sandwiched between contact objects such as a cleaning blade, a roller, and a transfer object.

  In addition, the inorganic fine powder does not necessarily exist as primary particles on the surface of the colored particles, and may exist as an aggregate, but even in that case, the content of the aggregate having a particle diameter of 600 nm or more is 1% by number or less. It is preferable that

  When an aggregate having a particle diameter of 600 nm or more is contained, even if the primary particle diameter is 300 nm or less, scratches on the photosensitive member are likely to occur, which is not suitable. The particle size of cubic strontium titanate in the present invention was determined by measuring 100 particle sizes from a photograph taken at a magnification of 50,000 times with an electron microscope. The particle diameter was determined by (a + b) / 2, where a is the longest side of the primary particles and b is the shortest side.

  Cubic strontium titanate can be surface-treated with a fatty acid or a fatty acid metal salt to make it difficult to fuse together with a photoreceptor or a developing roller.

The number of carbon atoms of the fatty acid or fatty acid metal salt for surface treatment of cubic strontium titanate is preferably 8 or more and 35 or less, and more preferably 10 or more and 30 or less. If the number of carbon atoms exceeds 35, the adhesion between the surface of the cubic strontium titanate inorganic fine powder and the fatty acid or fatty acid metal salt is inferior, and the durability decreases due to long-term use. Or a fatty acid metal salt is not preferable because it causes fogging. On the other hand, when the number of carbon atoms is less than 8, it is not preferable because the adhesion of fine particles having a specific surface area of 100 m ² / g to 350 m ² / g is insufficient.

  Moreover, the preferable processing amount of a fatty acid or a fatty acid metal salt is 0.1 mass% or more and 15 mass% or less with respect to a base material, More preferably, it is 0.5 mass% or more and 12 mass% or less.

  In addition, when surface treatment of cubic strontium titanate is performed using a treatment agent such as a silicone oil, a silane coupling agent, or a titanium coupling agent that is generally used to improve the hydrophobicity of the external additive, the aforementioned adhesion There was no improvement in sex. This is because fatty acids or fatty acid metal salts have excellent releasability and improve adhesion, while silicone oil, silane coupling agents, titanium coupling agents, etc. have excellent hydrophobicity, but release It seems to be inferior.

When titanium strontium titanate is externally added to the toner, the cubic titanium treated according to the present invention is used to prevent the influence of moisture absorption of the inorganic fine powder in a high-humidity environment on the development process, for example, reduction in toner charge amount. The specific surface area of strontium acid is preferably 45 m ² / g or less. By setting the specific surface area to 45 m ² / g or less, the absolute amount of water adsorbed on the surface of the inorganic fine powder can be kept small, so that the influence on the toner charge imparted by frictional charging can be reduced.

  In addition, the specific surface area of this invention was computed using the BET multipoint method using the autosorb 1 (made by Yuasa Ionics).

Furthermore, in order to prevent fine particles having a specific surface area of 100 m ² / g or more and 350 m ² / g or less from adhering to the surface of cubic strontium titanate in a low-humidity environment, the contact angle of cubic strontium titanate treated with the present invention with water. Is more preferably 110 ° or more and 180 ° or less.

The contact angle measurement method is as follows. Cubic strontium titanate was pressed by a tablet molding machine at a pressure of 300 KN / cm ^{2 to} obtain a sample having a diameter of 38 mm. At the time of molding, NP-Transparency TYPE-D was sandwiched between the molding machine and the sample. This sample was allowed to stand at 23 ° C. and 100 ° C. for 2 minutes and then returned to room temperature, and the contact angle was measured with a roll material contact angle meter CA-X roll type (manufactured by Kyowa Interface Chemical Co., Ltd.). The measurement was performed 20 times per sample, and the average value of 18 measured values excluding the maximum value and the minimum value was used.

In order to improve the developability, the absolute value of the charge amount of the cubic strontium titanate subjected to the surface treatment of the present invention is preferably 10 mC / Kg or more and 80 mC / Kg or less, and the charge polarity is 100 m in specific surface area. ^The polarity is preferably opposite to that of the fine particles of ² / g or more and 350 m ² / g or less.

  The method for measuring the charge amount is as follows.

Using a DSP 138 (manufactured by Dowa Iron Industries Co., Ltd.) as a carrier at a temperature of 23 ° C. and a relative humidity of 60%, a mixture obtained by adding 0.1 g of the sample to be measured to 9.9 g of the carrier is placed in a 50 ml capacity polyethylene bottle. Shake 100 times. Next, as shown in FIG. 5, about 0.5 g of the mixture is put in a metal measuring container 2 having a metal mesh screen 3 with a mesh opening of 32 μm at the bottom, and a metal lid 4 is formed. The total mass of the measurement container 2 at this time is weighed and is defined as W1g. Next, in the suction machine 1 (at least the part in contact with the measurement container 2) is suctioned from the suction port 7 and the air volume control valve 6 is adjusted to set the pressure of the vacuum gauge 5 to 250 mmAq. In this state, suction is performed for 2 minutes, and the sample to be measured is removed by suction. The potential of the electrometer 9 at this time is set to V (volt). Here, 8 is a capacitor, and the capacity is C (μF). Moreover, the mass of the whole measuring machine after suction is weighed and is defined as W2 (g). The triboelectric charge amount (mC / kg) of the sample to be measured is calculated as follows.
Frictional charge amount = CV / (W1-W2)

  Cubic strontium titanate used in the present invention is prepared by adding a strontium hydroxide to a dispersion of titania sol obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate, for example. It can be synthesized by heating up to.

  By setting the pH of the hydrous titanium oxide slurry to 0.5 to 1.0, a titania sol having good crystallinity and particle size can be obtained.

  For the purpose of removing ions adsorbed on the titania sol particles, it is preferable to add an alkaline substance such as sodium hydroxide to the titania sol dispersion. At this time, it is preferable that the pH of the slurry is not 7 or higher so that sodium ions and the like are not adsorbed on the surface of the hydrous titanium oxide.

  The reaction temperature is preferably about 60 ° C to 100 ° C. In order to obtain a desired particle size distribution, the temperature rising rate is preferably 30 ° C / hour or less, and the reaction time is preferably 3 to 7 hours.

  The inorganic particles thus produced can be obtained as perovskite crystals having a cubic or rectangular parallelepiped shape. When the particle shape is a cubic shape or a rectangular parallelepiped shape, the contact area with the surface of the photoreceptor can be increased, and a good scraping property by the solid ridgeline can be obtained. Further, by effectively using the particle size and the three-dimensional ridgeline and corner according to the surface shape of the photoconductor, it is possible to prevent deposits from depositing on fine irregularities when the photoconductor is particularly difficult to wear.

  Furthermore, at the same time as removing the adhering matter to the photosensitive member, it serves as a lubricant by appropriately slipping only the abrasive between the cleaning blade and the photosensitive member, thereby enabling the cleaning blade to be used for a long time.

  An example of an electron micrograph (magnification of 20,000 times) of the cubic strontium titanate of the present invention is shown in FIG.

<Effects and effects of external addition of cubic strontium titanate and large-diameter strontium titanate>
In addition, cubic strontium titanate is preferably used with larger abrasives having different particle sizes. The material is preferably the same as that of the above-mentioned abrasive from the viewpoint of triboelectric charging properties and electrical characteristics. Therefore, strontium titanate (hereinafter, large diameter strontium titanate) is desirable.

  Although the abrasive with a large particle size has a small ability to remove deposits on fine irregularities on the surface of the photoconductor, it is difficult to remove from the cleaning blade, and when it has a particle size of 0.60 μm or more, it exhibits performance as a cleaning aid for a long time. I can do it. Therefore, the small-diameter cubic strontium titanate adheres to the large-diameter strontium titanate, preventing the strontium titanate from slipping through the cleaning blade at once, and cleaning the abrasive with a high degree of polishing for a long time. Can contribute.

  Further, it is desirable that the abrasive having a large particle diameter of 0.60 μm or more has a spherical or irregular shape. Large cubic abrasives are not suitable because they tend to cause deep scratches on the surface of the photoreceptor when sandwiched between the photoreceptor and the cleaning blade.

  In order to obtain sufficient performance in the cleaning process of the large-diameter strontium titanate and the small-diameter cubic strontium titanate mixed toner, 5.0% by mass or more of strontium titanate is preferably present in the transfer residual toner. If it exceeds mass%, large and small strontium titanates tend to agglomerate and pack in the cleaning means, especially when the waste toner transportability decreases and the toner overflows or there is a brush or the like. Therefore, sufficient performance cannot be demonstrated.

  On the other hand, external addition of cubic strontium titanate to the toner affects the fixing performance.

  As a result of studies by the present inventors, the fixing performance of a toner containing strontium titanate having different particle diameters is not generally determined by the particle diameter / number, but the total amount of strontium titanate, which is a fixing inhibitor, on the transfer medium. It has been found that good fixing performance can be obtained if the total amount of strontium titanate on the transfer material including the large and small diameters is 1.8% by mass or less.

  The strontium titanate after the transfer is released from the transfer material by the fixing device and moves to the fixing device. At this time, the strontium titanate acts as an abrasive cleaning aid for removing the fouling of the fixing device, particularly the toner fusion, and the total amount of strontium titanate on the transfer material including the large and small diameters of the toner is 0.4. It has also been found that this effect can be sufficiently exerted when the content is at least mass%. The small-diameter cubic strontium titanate has this effect, but it has also been found that if there is no large-diameter strontium titanate, it is difficult to move to the fixing member surface. This phenomenon is particularly prominent when a fixing bias is applied, and it is thought that cubic strontium titanate moves on the fixing member along with large-diameter strontium titanate having a larger charge amount than cubic strontium titanate. It is.

  From the above, if both the large-diameter strontium titanate and cubic strontium titanate are contained in the toner and appropriately distributed between the cleaning means and the transfer material in the transfer step, sufficient photosensitivity in the cleaning step can be obtained. Good fixing performance can be exhibited while satisfying body polishing performance.

<Toner>
The method for producing the toner of the present invention is not particularly limited, and a suspension polymerization method, an emulsion polymerization method, an association polymerization method, a kneading and pulverization method, and the like are used.

  Further, the toner of the present invention can provide a sufficient effect in both cases of non-magnetic toner and magnetic toner.

  A method for producing toner in the kneading and pulverizing method will be described below.

  Examples of the binder resin used in the pulverized toner of the present invention include polystyrene, poly-α-methylstyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, and styrene-vinyl acetate. Copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid acrylic copolymers, vinyl chloride resins, polyester resins, epoxy resins, phenol resins, polyurethane resins, etc. can be used alone or in combination. -Acrylic, styrene-methacrylic copolymer resin and polyester resin are preferred.

  Further, when the pulverized toner of the present invention is controlled to be positively charged, a modified product of a fatty acid metal salt or the like; 4 such as tributylbenzidyl ammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, etc. Onium salts such as quaternary ammonium salts and their analogs such as phosphonium salts; amine and polyamine compounds; metal salts of higher fatty acids; acetylacetone metal complexes; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide Diorgano tin borate such as dibutyl tin borate, dioctyl tin borate, dicyclohexyl tin borate and the like are added. Moreover, when controlling to negative chargeability, an organometallic complex and a chelate compound are effective, and a monoazo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid metal complex can be used. The amount used is 0.1 to 15 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  A release agent can be added to the pulverized toner of the present invention as necessary. For example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, paraffin wax, and Fischer-Tropsch wax or oxides thereof; waxes mainly composed of aliphatic esters such as carnauba wax and montanic acid ester wax; And those obtained by deoxidizing some or all of them. In addition, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, and seryl alcohol , Saturated alcohols such as melyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide; saturated fatty acid bisamides such as methylene bis stearic acid amide; unsaturated fatty acid amides such as ethylene bisoleic acid amide Aromatic bisamides such as N, N′-distearylisophthalic acid amide; fatty acid metal salts such as zinc stearate; waxes grafted to a hydrocarbon hydrocarbon wax using a vinyl monomer such as styrene; Fatty acids with polyhydric alcohols partial esters of such Henin acid monoglyceride; and methyl ester having a hydroxyl group obtained by and hydrogenated vegetable oils may also be used. The addition amount is 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  Next, in the case of non-magnetic toners, these binder resins, mold release agents, charge control agents, colorants, etc., and in the case of magnetic toners, magnetic substances are used in place of the above colorants, or colorants as required. And a magnetic material are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melted and kneaded using a heat kneader such as a heating roll, a kneader or an extruder to charge the resin while the resins are compatible with each other. A control agent and a colorant are dispersed or dissolved, and after cooling and solidification, the particles are mechanically pulverized to a desired particle size, and the particle size distribution is sharpened by classification. Alternatively, after cooling and solidification, a finely pulverized product obtained by colliding with a target under a jet stream is spheroidized by heat or mechanical impact force.

Fine particles having a specific surface area of 100 m ² / g or more and 350 m ² / g or less are externally added to the colored particles thus obtained. The fine particles are inorganic particles such as metal oxides such as silicon, magnesium, zinc, aluminum, titanium, iron and zirconium; metal salts such as barium sulfate, calcium carbonate, magnesium carbonate and aluminum carbonate; clay minerals such as kaolin; apatite Phosphoric acid compounds such as silicon compounds such as silicon carbide and silicon nitride; and carbon powders such as carbon black and graphite. Organic particles and composite particles include polyamide resin particles, silicone resin particles, silicone rubber particles, urethane particles, melamine-formaldehyde particles, acrylic particles, etc .; rubber, wax, fatty acid compounds, resins, etc., metals, metals Composite particles composed of inorganic particles such as oxides, salts, carbon black, etc .; fluorine resins such as polyfluorinated ethylene and polyvinylidene fluoride; fluorine compounds such as carbon fluoride; fatty acid metal salts such as zinc stearate; Examples include fatty acid derivatives such as fatty acid esters; molybdenum sulfide, amino acids and amino acid derivatives.

These fine particles are for imparting appropriate fluidity and chargeability to the toner. If the specific surface area of the fine particles is less than 100 m ² / g, sufficient fluidity cannot be obtained, which is not preferable. Further, if the specific surface area of the fine particles exceeds 350 m ² / g, the charging becomes too high particularly in a low humidity environment, and filming on the photosensitive member is likely to occur, which is not preferable.

  The developing method using the toner of the present invention is not particularly limited. For example, a two-component developing method using a nonmagnetic toner manufactured by the above manufacturing method mixed with a carrier, a nonmagnetic one using only a nonmagnetic toner without using a carrier. Examples thereof include a component development method and magnetic one-component development using a magnetic toner.

<Electrophotographic photoreceptor 1 (organic photoreceptor)>
Hardness test is performed using Vickers square pyramid diamond indenter in an environment with a surface of 25 ° C and humidity of 50%, and HU (Universal Hardness Value) when pressed at a maximum load of 6 mN is 150 N / mm ² or more and 220 N / mm ² or less. In addition, the electrophotographic photosensitive member used in the present invention having high durability having an elastic deformation rate Wo of 44% or more and 65% or less will be described in detail including the production method.

  The electrophotographic organic photoreceptor of the present invention preferably has mainly a laminated structure, and a charge generation layer and a charge transport layer are provided in this order on a support.

In the present invention, a protective layer is applied on the charge transport layer and cured to form a film, and a hardness test is performed using a Vickers square pyramid diamond indenter in an environment with a surface of 25 ° C. and a humidity of 50%. A photoconductor having a HU (Universal Hardness Value) of 150 N / mm ² or more and 220 N / mm ² or less when pushed with a load of 6 mN and an elastic deformation rate Wo of 44% or more and 65% or less is completed.

  As a protective layer for an electrophotographic photoreceptor satisfying the above conditions, a protective layer containing a compound obtained by polymerizing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule as represented by the following chemical formula: is there.

式中、Ａは正孔輸送性基を示す。Ｐ¹及びＰ²は連鎖重合性官能基を示す。Ｐ¹とＰ²は同一でも異なってもよい。Ｚは置換基を有してもよい有機残基を示す。ａ、ｂ及びｄは０又は１以上の整数を示し、ａ＋ｂ×ｄは２以上の整数を示す。また、ａが２以上の場合Ｐ１は同一でも異なってもよく、ｄが２以上の場合Ｐ²は同一でも異なってもよく、またｂが２以上の場合、Ｚ及びＰ²は同一でも異なってもよい。

In the formula, A represents a hole transporting group. P ¹ and P ^{2 each} represent a chain polymerizable functional group. P ¹ and P ² may be the same or different. Z represents an organic residue which may have a substituent. a, b and d represent 0 or an integer of 1 or more, and a + b × d represents an integer of 2 or more. Further, a is or different in the case of two or more P1 identical, d is may be the case P ² of 2 or more the same or different and also when b is 2 or more, Z and P ² are either the same or different Also good.

  By polymerizing a hole transporting compound having two or more chain-polymerizable functional groups in the same molecule, the compound having a hole transporting ability in the protective layer has at least two or more crosslinking points. It is incorporated into the dimensional cross-linked structure via a covalent bond. The hole transporting compound can be either polymerized alone or mixed with a compound having another chain polymerizable group, and the kind / ratio is arbitrary. As used herein, the compound having another chain polymerizable group includes any monomer or oligomer / polymer having a chain polymerizable group. When the functional group of the hole transporting compound and the functional group of the other chain polymerizable compound are the same group or a group that can be polymerized with each other, they both take a copolymerized three-dimensional crosslinked structure via a covalent bond. Is possible. When both functional groups are functional groups that do not polymerize with each other, the photosensitive layer is a mixture of at least two or more three-dimensional cured products or other chain-polymerizable compound monomers in the three-dimensional cured product as a main component. Although it is comprised as the thing containing the hardened | cured material, it is also possible to form an IPN (Inter Penetrating Network), ie, an interpenetrating network structure, by controlling the compounding ratio / film forming method well.

  By containing at least one of fluorine atom-containing resin, carbon fluoride, and polyolefin resin as a lubricant in the protective layer, the surface slipperiness and water repellency of the photoreceptor can be improved, and charging during repeated use, Deterioration of transfer efficiency and slipperiness due to chemical deterioration of the surface layer due to development, transfer, etc., and further deterioration of electrical properties such as sensitivity reduction and potential reduction are prevented. Filming, fusing, and cleaning failure even during repeated use It is possible to suppress the occurrence of image defects such as image blur / flow. Particularly preferable results are obtained when the fluorine-containing resin is used. In the present invention, the proportion of the lubricant contained in the protective layer is preferably 1 to 70%, more preferably 5 to 50%, based on the total weight of the layer to be the surface layer. When the amount of the lubricant is more than 70%, the mechanical strength of the layer serving as the surface layer tends to be lowered, and when it is less than 1%, the water repellency and slipperiness of the layer serving as the surface layer may not be sufficient.

  In the present invention, a charge transport material can be contained in the protective layer containing the cured product of the hole transporting compound having the chain polymerizable group.

  The protective layer is generally formed by applying a solution containing the hole transporting compound and then carrying out a polymerization reaction, but a cured product obtained by reacting a solution containing the hole transporting compound in advance. After obtaining the above, it is possible to form a protective layer by dispersing or dissolving in the solvent again. As a method for applying these solutions, for example, a dip coating method, a spray coating method, a curtain coating method, a spin coating method, and the like are known. From the viewpoint of efficiency / productivity, the dip coating method is preferable.

  In the present invention, the hole transporting compound having a chain polymerizable group is preferably polymerized by radiation. The greatest advantage of polymerization by radiation is that a polymerization initiator is not required, which makes it possible to produce a very high-purity three-dimensional photosensitive layer and to ensure good electrophotographic characteristics. In addition, because it is a short and efficient polymerization reaction, it is highly productive, and because of its high radiation permeability, it inhibits curing when thick films and additives such as additives are present in the film. The influence of the is very small. However, depending on the type of the chain polymerizable group and the type of the central skeleton, the polymerization reaction may not easily proceed, and in this case, it is possible to add a polymerization initiator within a range that does not affect the reaction. The radiation used at this time is an electron beam and a gamma ray. In the case of electron beam irradiation, any type of accelerator such as a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used. When irradiating with an electron beam, the irradiation conditions are very important in the photoreceptor of the present invention in order to develop electric characteristics and durability. In the present invention, the acceleration voltage is preferably 250 kV or less, and optimally 150 kV or less. The dose is preferably in the range of 10 kGy to 1000 kGy. When the accelerating voltage exceeds the above, the electron beam irradiation damage tends to increase on the photoreceptor characteristics. Further, when the dose is less than the above range, the curing tends to be insufficient, and when the dose is large, the photoreceptor characteristics are likely to be deteriorated.

  The photoconductor for hardness test prepared as described above is left in an environment of 25 ° C. and 50% humidity for 24 hours, and then Hu and elastic deformation are performed using the above-described microhardness measuring device Fischerscope H100V (Fischer). The rate Wo was determined.

  The HU (universal hardness value) and elastic deformation rate Wo in the present invention are the microhardness measuring device Fischerscope in which the indenter is continuously loaded and the indentation depth under the load is directly read to obtain the continuous hardness. Measurement was performed using H100V (Fischer). The indenter used was a Vickers square pyramid diamond indenter with a face angle of 136 °. The load conditions were measured stepwise up to a final load of 6 mN (273 points with a holding time of 0.1 s for each point). An outline of the output chart is shown in FIG. 3, and an example in which the electrophotographic photosensitive member of the present invention is measured is shown in FIG. The vertical axis represents the load (mN) and the horizontal axis represents the indentation depth h (μm), which is the result of increasing the load stepwise and applying the load to 6 mN, and then decreasing the load stepwise similarly. HU (universal hardness value: hereinafter referred to as HU) is defined by the following equation from the indentation depth under the same load when indented at 6 mN.

ｈ：試験荷重下での押し込み深さ（ｍｍ）

h: Indentation depth under test load (mm)

The elastic deformation rate Wo is obtained from the amount of work (energy) performed by the indenter on the membrane, that is, the change in energy due to the increase or decrease in the load of the indenter on the membrane, and the value can be obtained from the following equation.
Elastic deformation rate Wo = We / Wt × 100 (%)

  The total work Wt (nW) is represented by an area surrounded by A-B-D-A in FIG. 3, and the elastic deformation work We (nW) is represented by an area surrounded by C-B-D-C. Is done.

  As described above, the performance required for the organic electrophotographic photosensitive member includes improved durability against mechanical deterioration. In general, the hardness of the film is higher as the amount of deformation with respect to external stress is smaller, and it is considered that the electrophotographic photosensitive member having higher pencil hardness or Vickers hardness naturally improves durability against mechanical deterioration. However, the high hardness obtained by these measurements has not always been expected to improve durability.

As a result of intensive studies, it has been found that mechanical deterioration of the surface layer of the photoreceptor hardly occurs especially in a high temperature and high humidity environment when the values of HU and elastic deformation rate Wo are within a certain range, and the present invention has been achieved. That is, a hardness test is performed using a Vickers square pyramid diamond indenter, the HU when pressed at a maximum load of 6 mN is 150 N / mm ² or more and 220 N / mm ² or less, and the elastic deformation rate Wo is 44% or more and 65%. The use of the following electrophotographic photosensitive member has improved dramatically.

Although the HU and the elastic deformation rate Wo cannot be separated from each other, for example, when the HU exceeds 220 N / mm ² , or when the friction with the cleaning blade increases at high temperatures, the elastic deformation rate Wo is If it is less than 44%, the elastic force of the photosensitive member is insufficient. Therefore, if the elastic deformation rate Wo is greater than 65%, the elastic deformation amount is small even if the elastic deformation rate is high. Will cause deep scratches. Therefore, it is considered that the one with a high HU is not necessarily optimal as the photosensitive member.

Further, when the HU is less than 150 N / mm ² and the elastic deformation rate Wo exceeds 65%, even if the elastic deformation rate is high, the amount of plastic deformation becomes large, and the paper dust sandwiched between the cleaning blade and the charging roller If the toner is rubbed, it may be scraped off or fine scratches may occur.

<Electrophotographic photoreceptor 2 (amorphous silicon photoreceptor)>
The Vickers hardness of the amorphous silicon photoconductor of the present invention is measured by a measuring method according to JIS standard B7774. A photoreceptor having low elasticity such as an amorphous silicon photoreceptor is sufficiently hard to have a Vickers hardness of 500 kg / m ² or more, and the above-described fine surface shape can be maintained for a long time. If it is less than 500 kg / m ² , the growth of wear and scratches is rapid and it becomes difficult to maintain the surface shape.

<Development sleeve>
The resin film layer formed on the surface of the developing sleeve will be described. The developing sleeve has a coating layer formed on the surface of the sleeve base tube. According to the present invention, the coating layer contains a charge control agent and conductive fine particles in the coating-forming polymer material (resin). It is formed using things.

  Furthermore, spherical particles subjected to conductive treatment can be contained in the binder resin. If such particles are present in the binder resin, even if the coating layer is worn by a long-term durability test (long-term use), the conductively treated spherical particles are exposed, and the conductivity of the coating layer is maintained. Excessive charging is prevented.

  Furthermore, since the spherical shape of the conductive particles is spherical, the surface roughness of the coating layer is kept uniform even during the long-term durability test (long-term use), and the toner transportability to the developing part is also constant. It is kept. For this purpose, the surface roughness of the coating is preferably in the range of 0.2 to 3.5 μm in terms of JIS centerline average roughness (Ra). When Ra is less than 0.2 μm, the charge amount of the toner on the developer carrying member increases, and the developability becomes insufficient. If Ra exceeds 3.5 μm, unevenness occurs in the toner coat layer on the developer carrying member, resulting in uneven density on the image.

  A preferred sleeve surface in the present invention has an unevenness Ra formed mainly by spherical carbon particles of 0.3 to 0.9 μm, and this unevenness effectively imparts strontium titanate to the sleeve surface and imparts positive friction charging. The strontium titanate can be more positively charged positively. When positive toner is used, it is preferable to use a charge control material having a high negative friction charge imparting property. If the unevenness Ra on the sleeve surface is too large, particularly cubic strontium titanate is liable to be stuck in the groove, and if it is too small, the rubbing effect is reduced.

  Next, each material constituting the coating layer will be described. Examples of the conductive spherical particles include metal oxides such as zinc oxide, zinc sulfide, barium sulfate, titanium oxide, tin oxide, niobium oxide, manganese oxide, lead oxide, copper oxide, indium oxide, iridium oxide, and composite types thereof. Metal oxide coated with a highly conductive material or doped with a material having a different oxidation number, conductive treatment; resin-based spherical particles such as phenol resin; carbonization and / or graphite by firing mesocarbon microbeads Bulk mesophase pitch (petroleum-based or coal-based pitch containing optically anisotropic liquid crystal called mesophase) by a mechanochemical method on the surface of resin-based spherical particles of a specific material using a crusher such as a jaw crusher Coarsely pulverized and then finely pulverized with a dry or wet ball mill etc.) and heat-treated under certain conditions After burned, the surface or the like that is conductive by causing carbonization are cited. These can be used alone or in combination of two or more. In addition, it is preferable that the volume average particle diameter of the electroconductive spherical particle used for this invention is the range of 0.2-50 micrometers. If it is less than 0.2 μm, it is difficult to obtain a suitable surface roughness of the developer carrying member, and image quality is likely to deteriorate. If the thickness exceeds 50 μm, it protrudes from the surface of the coating, and unauthorized development tends to occur only in that portion, which is not preferable.

  The conductive substance other than the conductive spherical particles used as necessary is used to adjust the resistance value of the coating layer. For example, metal powder such as aluminum, copper, nickel, silver, etc .; antimony oxide And metal oxides such as indium oxide and tin oxide; and carbon materials such as carbon fiber, carbon black, and graphite. Of these, carbon black, especially conductive amorphous carbon, is particularly excellent in electrical conductivity, and can be filled with a polymer material to impart conductivity, or a wide range of conductivity can be obtained by controlling the amount added. Preferably used. In addition, when using electroconductive amorphous carbon, it is preferable that the volume average particle diameter is the range of 10-80 mmicrometer.

  Further, in order to further reduce the adhesion of the toner to the developer carrying member, a solid lubricant can be contained in the coating layer as necessary. Examples of the solid lubricant include molybdenum disulfide, boron nitride, graphite, graphite fluoride, silver-selenium niobium, calcium chloride-graphite, talc and the like. Of these, graphite is preferably used because it has conductivity as well as lubricity, has a function of reducing toner having an excessively high charge, and having a charge amount suitable for development.

  Examples of the binder resin for forming a coating layer in which the conductive spherical particles and the low surface energy spherical particles are dispersed include phenolic resins, epoxy resins, polyamide resins, polyester resins, polycarbonate resins, and polyolefin resins. Known resins such as silicone resins, fluorine resins, styrene resins, and acrylic resins are used. In particular, a thermosetting or photocurable resin is preferable.

  As the charge control agent, a quaternary ammonium salt compound represented by the following general formula is preferable. When a coating layer is formed using a resin composition obtained by adding a specific quaternary ammonium salt compound to a coating resin, When the coating resin is cured to form the coating layer, the quaternary ammonium salt compound is incorporated into the structure of the phenol resin. For this reason, unlike the case of a particle addition system such as negative silica particles or negative fluororesin particles, the positive triboelectric charge imparting property is improved as a whole coating layer, not partially.

（式中のＲ₁、Ｒ₂、Ｒ₃、Ｒ₄は、夫々置換基を有してもよいアルキル基、置換基を有してもよいアリール基、アルアルキル基を表わし、Ｒ₁〜Ｒ₄は夫々同一でも或いは異なっていてもよい。Ｘ^-は、酸の陰イオンを表わす。）

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group which may have a substituent, an aryl group which may have a substituent, and an aralkyl group, respectively, and R _{1 to} R ₄ may be the same or different, and X ⁻ represents an anion of an acid.)

  Further, as the solid lubricant, the coating resin contains an inorganic powder having conductivity or semiconductivity and having a triboelectric charge polarity opposite to that of the toner. The contact between the inorganic powder and the toner on the sleeve improves the fluidity of the toner on the developing sleeve, prevents charge accumulation on the sleeve, and gives the toner a sufficient and appropriate charge amount. become. Examples of such inorganic powder include molybdenum disulfide, graphite, tungsten disulfide, silicon carbide, boron nitride and the like.

  A coating material for forming a film is prepared using each component described above, and this coating material is applied to the surface of the developer carrier substrate and dried to obtain a developer carrier having a coating layer. Each of the spherical particles to be dispersed in the binder resin and the conductive material and / or solid lubricant used as needed are usually 3 to 200 parts by weight of conductive spherical particles per 100 parts by weight of the binder resin. Used in the range of 3 to 200 parts by weight of low surface energy spherical particles, 0 to 200 parts by weight of a conductive substance and 0 to 200 parts by weight of a solid lubricant, and is produced by uniformly mixing and dispersing in a binder solution. The The production of the paint is not particularly limited as long as it follows a normal paint production method. The coating layer 1 is formed by applying a coating material for forming a coating on the surface of the developer carrier substrate 7 so as to have a predetermined dry thickness by a normal coating method such as spraying and drying. The thickness of the coating layer is usually in the range of 2 to 200 μm.

  Hereinafter, specific examples will be described. Part means part by mass.

<Photoreceptor Production Example 1>
Using an aluminum cylinder (JIS A3003 aluminum alloy) having a length of 260.5 mm and a diameter of 30 mm as a support, a 5% by mass methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was applied thereon by a dipping method. An undercoat layer having a thickness of 0.5 μm was formed.

  Next, 3 parts of hydroxygallium phthalocyanine crystal and 2 parts of polyvinyl butyral having the strongest peak at a diffraction angle 2θ ± 0.2 of 28.1 ° in CuKα X-ray diffraction are added to 100 parts of cyclohexanone as charge generation materials. Disperse in a sand mill using 1 mmφ glass beads for 1 hour, add 100 parts of methyl ethyl ketone and dilute it to prepare a charge generation layer coating, and immerse this charge generation layer coating on the undercoat layer This was applied and dried at 90 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.17 μm.

  Next, 7 parts of a charge transport material compound of the formula

  And 10 parts of polycarbonate resin (Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) were dissolved in 105 parts of monochlorobenzene and 35 parts of dichloromethane. This solution was dip-coated on the charge generation layer and dried with hot air at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 13 μm. This further protective layer was formed on the charge transport layer.

  In this embodiment, reversal development is used, and the photoreceptor is polymerized by electron beam irradiation with a hole transporting compound of the following chemical formula as a surface protective layer after three layers are stacked on an aluminum cylinder having a diameter of 30 mm as described above. An organic photoreceptor obtained by applying and curing a surface layer containing the prepared compound.

Dissolve 45 parts of this hole transporting compound in 55 parts of n-propyl alcohol, add 10 parts of tetrafluoroethylene fine particles (PTFE), and disperse with a high-pressure disperser (microfluidizer, manufactured by Microfluidics). A coating for the surface protective layer was prepared. After applying this paint on the four-layer photoconductor, an electron beam was irradiated under the conditions of an acceleration voltage of 150 KV and a dose of 100 kGy to form a protective layer having a thickness of 3 μm to obtain an electrophotographic photoconductor. Hu of the surface of the obtained photoreceptor was 190 N / mm ² and Wo was 52 (%).

<Photosensitive member production example 2>
Using an apparatus for manufacturing a photoreceptor for electrophotographic apparatus by a high frequency plasma CVD method using a VHF band, an amorphous silicon photosensitive film comprising a charge injection blocking layer, a photoconductive layer and a surface layer on an aluminum cylinder having a mirror finish of φ30. The body was made. The surface layer was a-C. The obtained photoreceptor had a Vickers hardness (JIS standard) of 1300 kg / m ² .

<Production example of cubic strontium titanate>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.65 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 4.5, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.

0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Further distilled water was added so as to 0.1～2.0Mol / liter terms of SrTiO _3.

  The slurry was heated to 83 ° C. at a rate of 5 to 30 ° C./hour in a nitrogen atmosphere, and reacted for 3 to 7 hours after reaching 83 ° C. After the reaction, cool to room temperature, remove the supernatant, and repeat washing with pure water.

  Further, in a nitrogen atmosphere, the slurry was placed in an aqueous solution in which 6.5% by mass of sodium stearic acid (18 carbon atoms) was dissolved with respect to the solid content of the slurry. Zinc stearate was deposited on the mold crystal surface.

  The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate surface-treated with zinc stearate.

  The obtained strontium titanate had an average primary particle size of 110 nm and an agglomerate content of 600 nm or more of 0.5% by number. The content of particles having a cubic or rectangular parallelepiped shape was 80% by number or more.

<Production example of large diameter strontium titanate>
600 g of strontium carbonate and 320 g of titanium oxide were wet mixed in a ball mill for 8 hours and then filtered and dried. This mixture was molded at a pressure of 5 kg / cm ² and calcined at a temperature of 1100 ° C. for 8 hours. Thereafter, the mixture was mechanically pulverized to obtain a fine strontium titanate powder having a weight average diameter of 1.8 μm, a number average diameter of 0.7 μm, and a particle size distribution [(m-D4) / (m-D1)] of 2.6. Coarse powder and fine powder are simultaneously removed by an elbow jet classifier using the Coanda effect to obtain a weight average diameter of 1.4 μm, a number average diameter of 1.0 μm, and a particle size distribution [(m−D4) / (m−D1]. ] An irregular large-diameter strontium titanate of 1.4 was obtained.

<Examples of colored particle production>
Styrene acrylic resin 100 parts (styrene-butyl acrylate copolymer ratio = 78: 22)
Magnetic material 90 parts Salicylic acid metal compound 2 parts Paraffin wax 3 parts The above is mixed using a Henschel mixer, melt kneaded with a twin screw extruder kneader, coarsely pulverized with a hammer mill, and finely pulverized with a jet mill. Classification was performed to obtain colored particles having an average particle diameter of 7 μm.

<Developer external additive prescription>
100 parts of colored particles, 1.2 parts of hydrophobic silica (BET = 220 m ^{2 /} g) surface-treated with 20 parts of dimethyl silicone oil on 100 parts of silica, 0 to 2 parts of cubic strontium titanate, and large-diameter titanic acid 0-3 parts of strontium Henschel mixer FM10B, rotational speed: 33S ^-1 or 66S ^-1, time: externally added in 2 minutes conditions toner A1～Y1, to give a A2～Y2, which actual image Used for taking out. The obtained toner is shown in Tables 1 and 2.

<Development sleeve>
After mixing the following materials, using a zirconia particle of φ2 mm as a filler and dispersing for 3 hours in a sand mill, the zirconia particles are separated by sieving, and the solid content is adjusted to 30% with IPA. A resin composition in which a quaternary ammonium salt compound that is positively charged with respect to iron powder was added to the resin was obtained.
・ Carbon 20 parts ・ Graphite 60 parts ・ Spherical carbon particles (particle size 5 μm) 15 parts ・ Phenol resin manufactured using ammonia as a catalyst (solid content 50%) 500 parts ・ Quaternary ammonium salt compound of the following formula (1) 15 parts methanol 150 parts

  The resin composition obtained above is in the form of a paint, and the composition is carbon / graphite / phenol resin / spherical carbon particles / quaternary ammonium salt compound = 0.2 / 0.6 / 2.5. /0.15/0.15. Next, this resin composition is applied by spraying onto a 20 mm aluminum cylinder to form a 20 μm film, and then heated and cured at 150 ° C. for 30 minutes with a hot air dryer, A developing sleeve having a conductive resin coating layer was prepared. The volume resistance value of the resin composition used above was coated with a coating resin composition on an insulating sheet with a bar coater, dried, then cut into a regular shape, and a low resistivity meter Lorester (Mitsubishi) (Manufactured by Yuka Co., Ltd.). As a result, it was 1.5 × 10Ω · cm.

  Further, the obtained developing sleeve was polished on the surface of the developing sleeve on which the resin coating layer was formed while adjusting the polishing strength (pressure) using a polishing apparatus. Ra of the sleeve surface irregularities was 0.6 μm.

[Examples 1 to 26, Comparative Examples 1 to 49]
<Reverse toner non-image discharge mode>
During normal image formation and development, the DC component is −540 V as the development bias, and an AC bias of 800 Vpp is superimposed, but a reverse bias consisting of an AC bias of DC components +500 and 800 Vpp is applied between the papers on the photoreceptor. Is provided with a mode for discharging the reversal component.

<Evaluation method>
The cleaning performance was evaluated by printing 200,000 sheets of 5% images with a modified Canon digital copier iR400 in an environment of a temperature of 23 ° C. and humidity of 5% RH. The evaluation was based on one image.
◎: No slipping through ○: Charging member is soiled but slipping out does not appear in the image △: Charging member is soiled and can be seen slightly in halftones x: Several images are printed at locations corresponding to scratched portions of the photoreceptor Slipping out

The evaluation of image flow was performed at a temperature of 30 ° C and humidity of 80% RH in a Canon digital copier iR400 remodeled machine that produced 100,000 images with a 5% image, and after the 100,000 images were printed. After turning off the power, the digital halftone image and the 5-point character image after being left in the same environment for 24 hours were evaluated. The evaluation results were ranked as follows.
○: No image flow ×: Halftone highlight is completely skipped and characters are blurred and cannot be read

Evaluation of waste toner transportability was performed at a temperature of 30 ° C and humidity of 80% RH with a Canon digital copier iR400 remodeling machine to print 100,000 sheets of 5% images from the end of the waste toner box. The degree of contamination due to spilled toner was evaluated.
○: Toner is not spilled ×: Toner is slightly spilled

  The durability of the cleaning blade is evaluated at a temperature of 30 ° C and humidity of 80% RH. Canon digital copying machine iR400 modifies 200,000 images with a 5% image, and the cleaning blade edge at that time The slippage due to destruction was performed by observing a solid white image after the solid black paper was passed.

The blade edge was observed with a microscope to confirm the position of destruction, and was made to correspond to the slip-through position.
◎: No slipping at all ○: Slightly slipping through, but the charging roller is soiled to a degree that does not appear in the image Δ: Slightly slipping out but is hardly noticeable in the image ×: Cannot be evaluated because it cannot be cleaned sufficiently

  Fixability was evaluated by a rubbing test. The rubbing test is a method for evaluating the degree of toner peeling when a fixed image is rubbed as an image density reduction rate.

When the image density before rubbing of the fixed image (solid portion) is D1, and the image density after rubbing is D2, the fixability F in the rubbing test is F = (D1-D2) / D1 × 100 (%)
It is represented by

  The reflection density of the image after fixing (24φ halftone) was measured with a Macbeth reflection densitometer, and three Sylbon Cs were attached to the bottom surface of a 200 g true casting of a rectangular parallelepiped having a bottom surface of 22.5 mm × 22.5 mm. Then, the image density D2 is measured after rubbing 5 reciprocations at a speed of 1 reciprocation 1 second with a pressure of only the weight of the true cast cuboid on the smooth surface of Sylbon C.

The measurement was performed on an image sample that was fixed at the lowest temperature at which the fixability F was 5% or less when a rubbing test was performed using a toner containing no strontium titanate. Canon white recycled paper EW500 was used as the paper to be used.
○: Less than 15% Δ: 15 or more and less than 30% ×: 30% or more

The life of the fuser is evaluated by using a Canon digital copier iR400 modified machine at a temperature of 23 ° C and a humidity of 5% RH to produce a 20% image. Whether or not the image defect due to the occurrence of the solid white image was evaluated.
○: No problem for 400,000 or more sheets ×: Generated within 400,000 sheets

  The results of evaluation according to the above criteria are shown in Table 3, Table 4, and Table 5. Note that the organic photoreceptor of the photoreceptor 1 was used as the photoreceptor.

  The amount of strontium titanate in the transfer residual toner (toner collected from the photoreceptor by the cleaning blade) and the toner on the transfer material was quantified with a fluorescent X-ray analyzer (Rigaku: RIX-3000). Quantification was performed using a calibration curve method. A known sample was prepared by adding strontium titanate to a toner containing no strontium titanate, and a calibration curve of strontium atoms was obtained. Further, in the analysis of the transfer residual toner, the zinc atom was also quantified to calculate the value of β / α.

Example 27
When a Canon copier NP6350 modified machine was evaluated under the same conditions as GP 405 with photoreceptor 2, toner M-1, discharge mode, and photoreceptor heater off, the following results were obtained.
Content of strontium titanate in transfer residual toner: 10.0% by mass
Strontium titanate content in toner on transfer material: 0.9% by mass
β / α: 0.42
Cleanability: ○ Image flow: ○ Waste toner transport: ○
Fixing property: ○ Fixing device life: ○ Cleaning durability life: ◎

  In the amorphous silicon of the photoconductor 2, the photoconductor was hardly scraped and the surface roughness was almost the same as in the initial stage.

  As described above in Examples 1 to 27, using a highly durable photoconductor and a developing sleeve having an appropriate surface roughness, a spherical shape having a primary particle size of 0.60 μm or more and a toner number average particle size or less. Alternatively, it contains an amorphous strontium titanate powder and strontium titanate whose primary particles are cubic and / or rectangular parallelepiped and whose average primary particle size is 0.030 to 0.300 μm. The content of strontium titanate in the transfer residual toner is 5.0% by mass or more and 20.0% by mass or less, and the content of strontium titanate inorganic powder in the toner on the transfer material after transfer. When the amount is 0.4% by mass or more and 1.8% by mass or less, strontium titanate is appropriately charged on the surface of the sleeve opposite to the toner, so that an appropriate amount can be left on the photoreceptor in the development and transfer processes. Therefore, it becomes easy to provide an appropriate amount of strontium titanate for the cleaning process and the fixing process, and cubic strontium titanate and large-diameter strontium effectively act as cleaning aids. Accordingly, it is possible to perform image formation over a long period of time with high image flow prevention performance, improved cleaning performance, and good fixing performance.

  Further, as shown in Examples 18 to 27, when the reverse toner discharge mode is provided, strontium titanate charged to a polarity opposite to that of the toner is selectively moved to the photosensitive member and supplied to the cleaning unit without being transferred. Therefore, it becomes easy to improve the cleaning property by adding a smaller amount of strontium titanate, and the strontium titanate in the toner on the transfer material is also appropriate, thereby improving the fixing property.

Further, as shown in Examples 4, 5, 8, 11 to 13, 15, 16, 20, 21, and 24 to 27, the spherical or amorphous strontium titanate inorganic powder is further contained in the transfer residual toner. When the content of strontium titanate in which the rate is α mass% and the primary particles are cubic and / or rectangular parallelepiped particle shapes are β mass%, the following formula: 0.1 ≦ β / α ≦ 0.5
By satisfying the above, better cleaning properties can be exhibited.

  Further, as shown in Example 27, by using an amorphous silicon photosensitive member as the photosensitive member, the photosensitive member is hardly damaged, and stable image formation can be performed over a longer period.

1 is a schematic cross-sectional view showing an image forming apparatus according to the present invention. It is an enlarged photograph of the abrasive particle concerning this invention by an electron microscope. It is the schematic of the output chart which measures the elasticity modulus of the electrophotographic photosensitive member of this invention. It is the example which measured the elasticity modulus of the electrophotographic photosensitive member of this invention. It is the schematic of the apparatus used for the measurement of a charge amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Photoconductor 102 Charging roller 103 Exposure apparatus 104 Developing apparatus 105 Transfer member 106 Fixing apparatus 107 Cleaning apparatus 111 Transfer material

Claims (7)

The surface of the photoreceptor is charged, an electrostatic latent image is formed on the photoreceptor, a developer is carried on the developer carrier, and the developer latent image is applied to the surface of the photoreceptor to form the electrostatic latent image. In the image forming method of developing, transferring the developed toner image to a transfer material, and fixing the developer on the transfer material by a fixing unit,
In the developer, spherical or irregular strontium titanate inorganic powder having a primary particle size of 0.60 μm or more and not more than the number average particle size of the toner, and cubic particles and / or cuboid particles of primary particles Containing strontium titanate having a shape and an average primary particle size of 0.030 to 0.300 μm,
The content of strontium titanate in the transfer residual toner is 5.0% by mass or more and 20.0% by mass or less, and the content of strontium titanate inorganic powder in the toner on the transfer material after the transfer is 0. 0%. An image forming method, wherein the content is 4% by mass or more and 1.8% by mass or less. The photoreceptor has a photosensitive layer on a conductive support, and the surface of the photosensitive layer is subjected to a hardness test using a Vickers square pyramid diamond indenter in an environment of 25 ° C. and 50% humidity, and is pressed with a maximum load of 6 mN. Characterized in that it has an electrophotographic photosensitive member surface having an HU (Universal Hardness Value) of 150 N / mm ² or more and 220 N / mm ² or less and an elastic deformation rate Wo of 44% or more and 65% or less. The image forming method according to claim 1. The developer carrier has at least a substrate and a resin coating layer provided on the substrate, and the resin coating layer has a conductive spherical carbon having a number average particle size of 0.3 to 20 μm and a true density of 3 g / cm ³ or less. 3. The image forming method according to claim 1, wherein the image forming method according to claim 1, wherein the image forming method comprises particles, and the Ra of the surface irregularity of the resin coating layer is 0.3 to 0.9 μm.   4. The image forming method according to claim 1, wherein each of the strontium titanate inorganic powders is charged oppositely to the toner.   5. The image formation according to claim 1, wherein a reverse bias is applied during non-image formation to develop a reversal toner on the photoconductor, and the reversal toner is provided on the photoconductor. Method. The content of the spherical or irregular shaped strontium titanate inorganic powder in the transfer residual toner is α mass%, and the content of the strontium titanate in which the primary particles are cubic and / or rectangular particles. When β mass%, the following formula: 0.1 ≦ β / α ≦ 0.5
The image forming method according to claim 1, wherein: The photoconductor has a photoconductive layer composed of a non-single crystal material having a silicon atom as a base material, and has a Vickers hardness (JIS standard) of 500 kg / m ² or more. The image forming method according to claim 6.

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