JP5300360B2 - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner that prevents abnormal sounds by noises or vibrations of a photoreceptor or image defects for a long period of time, even in a combination of longer service life of a photoreceptor and power-saving of a charging device. <P>SOLUTION: The toner is used in an image forming method including an electrostatic latent image forming step of forming an electrostatic latent image on a charged electrostatic charge image carrier, a developing step of transferring toner carried by a toner carrier onto the electrostatic latent image to visualize the image, and a transfer step of transferring the toner image formed on the electrostatic charge image carrier onto a recording medium. The toner is characterized in that: the electrostatic charge image carrier is a photoreceptor having a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide successively layered; the sum of atomic density of silicon atoms and atomic density of carbon atoms in the surface layer of the photoreceptor is not less than 6.60&times;10<SP>22</SP>atoms/cm<SP>3</SP>; the toner comprises toner particles containing a binder resin and a colorant, and inorganic fine powder; and the inorganic fine powder shows Mohs hardness of from 4.0 to 7.0. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a toner and an image forming method used in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, or the like.

  More specifically, the present invention relates to a toner and an image forming method used in an image forming method such as a copying machine, a printer, and a fax machine in which a toner image is formed on a photosensitive member and then the toner image is transferred onto a transfer material to form an image. About.

  Conventionally, many methods are known as electrophotographic methods.

  In general electrophotography, a photoconductive substance is used to form an electrical latent image on an image carrier (photoconductor) by various means, and then toner is developed on the latent image. It is known that a toner image is obtained by visualizing the toner image, and if necessary, the toner image is transferred to a transfer material such as paper and then the toner image on the transfer material is fixed by heat / pressure to obtain a copy. Yes.

  These image forming apparatuses using electrophotography are applied as printers and facsimiles in addition to copying machines.

  In recent years, with the development of the information industry and increasing environmental awareness, there has been a demand for an image forming apparatus with high image quality, long life, low running cost, small size, and low power for industrial or office use. In response to these demands, approaches from various directions of the electrophotographic main body, the photoreceptor, the developer, and various functional members have been made.

  For example, in a photoconductor, a long-life photoconductor is obtained by using an a-Si photoconductor having high wear resistance instead of a photoconductor using a low molecular organic photoconductive material having low wear resistance and poor durability. A method for reducing the running cost is known.

  In addition, as a charging device that charges the photosensitive member to a predetermined potential before forming a latent image, a charging device that contacts the photosensitive member is used instead of a conventional scorotron method that requires a high voltage. Thus, the charging device can be downsized, low ozone, and low power. For example, there is a contact charging method in which charging is performed by generating a proximity discharge in a minute gap between a charging member and a member to be charged, and an injection charging method in which electric charge is directly injected without discharging, and charging in contact with a photosensitive member. As a member, a roller type (charging roller), a fur brush type, a magnetic brush type, a blade type and the like are known.

  These contact charging devices have a structure in contact with the photosensitive member, and when the toner or inorganic fine powder contained in the toner remains on the photosensitive member, the charging device is contaminated with residual transfer toner and the like. This is likely to cause problems such as hindrance to the light and inability to perform uniform charging.

  In order to reduce the toner and inorganic fine powder remaining on the photoreceptor, it is important to improve the transfer efficiency when the developed toner image is transferred to the photoreceptor. Cleaning is performed in the process.

  As a cleaning process, for example, a method using a fur brush or a web is known, but a blade method with a low cost and a high cleaning performance is preferably used. For example, a blade-like cleaning member made of an elastic material such as rubber is pressed against the photoconductor, and residual transfer toner on the photoconductor is damped and collected.

  When using a contact charging device, it may be necessary to clean the charging device more precisely than with a non-contact charging device in order to prevent contamination of the charging device with transfer residual toner or the like. It may be necessary to press with strong pressure.

  In a high-abrasion a-Si photosensitive member, the frictional resistance may be increased when the cleaning member is strongly pressed. In particular, in a low-temperature and low-humidity environment, the cleaning member may squeal or chatter, Problems such as increased torque are likely to occur.

  As countermeasures against squeal and chatter, even with an a-Si photoconductor, it is easy to wear the surface layer by keeping the atomic density of the surface layer low, and image defects such as image flow due to wear of the surface layer. (For example, Patent Document 1) and frictional resistance can be suppressed.

  As for the relationship between the inorganic fine powder contained in the toner and the photoconductor, the surface of the photoconductor is polished by selecting an inorganic fine powder having a hardness equal to or higher than that of the photoconductor surface layer (for example, Patent Documents 2 to 3). There are known methods for promoting image quality and suppressing image defects. However, these methods of promoting the abrasion of the surface of the photoconductor, such as suppressing the atomic density of the surface layer of the photoconductor to a low level or adding a highly abrasive abrasive to the toner, reduce the life of the photoconductor by depleting the photoconductor. Will end up.

  Further, in these methods of maintaining the performance by continuing to wear the photoconductor, for example, when the output of a low-print original close to a plain color is continued, the supply of inorganic fine powder for polishing the photoconductor decreases. It may cause image flow and blade turning.

  As described above, in the conventional technique, it is necessary to wear the surface of the photosensitive member in order to suppress the noise and chatter of the cleaning member and to suppress image defects such as image flow. With an a-Si photoconductor, a certain long life can be expected even if the surface is worn. However, for further long life, it is preferable to suppress the wear on the surface of the photoconductor.

  Even if a photoconductor with a high atomic density of the surface layer and low wear is combined with a contact charging device with low power consumption, the above-mentioned squealing and chattering of the cleaning member does not occur, and wear of the photoconductor is not promoted. It has been difficult to obtain a long-life and low-power image forming apparatus that can suppress image defects such as image flow and achieve high image quality in a wide range of usage environments.

Japanese Patent No. 3124841 Japanese Patent Laid-Open No. 05-181306 JP 2004-163560 A

  An object of the present invention is to provide a toner and an image forming method that solve the above-mentioned problems of the prior art. That is, an object of the present invention is to suppress the noise and chatter when pressing the cleaning member with a strong pressure and cause no image defect even when using a photoconductor with a high atomic density of the surface layer that achieves a long life. It is possible to combine a long-life photoreceptor and a contact charging device for power saving.

  The invention relating to the present application for achieving the above-mentioned object is as follows.

(1) The present invention includes a step of charging an electrostatic charge image carrier with a charging member, an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic image carrier, and a toner carrier. A developing step for transferring the carried toner to the electrostatic latent image for visualization, a transfer step for transferring the toner image formed on the electrostatic charge image carrier onto a recording medium, and an electrostatic charge after the transfer step Oite the imaging how and a cleaning step for cleaning the surface of the image bearing member by a cleaning member,
The electrostatic image bearing member is an electrophotographic photosensitive member in which at least a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide are sequentially stacked, and the atomic density of silicon atoms and carbon atoms in the surface layer The sum of the atomic densities of 6.60 × 10 ²² atoms / cm ³ or more,
The toner is a toner having toner particles containing at least a binder resin and a colorant and an inorganic fine powder, the inorganic fine powder is strontium titanate, and the inorganic fine powder has a Mohs hardness of 4.0 or more and 7 0.0 or less.

  (2) The present invention is characterized in that the inorganic fine powder has a number average particle size of primary particles of 30 nm to 800 nm.

( 3 ) The present invention is characterized in that the inorganic fine powder contains 50% by number or more of particles having a hexahedral particle shape which is a convex polyhedron surrounded by six squares.

( 4 ) In the present invention, the ratio of the number of carbon atoms to the sum of the number of silicon atoms and the number of carbon atoms in the surface layer of the electrophotographic photosensitive member is 0.61 or more and 0.75 or less. It is characterized by.

( 5 ) In the present invention, the ratio of the number of hydrogen atoms to the sum of the number of silicon atoms, the number of carbon atoms, and the number of hydrogen atoms in the surface layer of the electrophotographic photosensitive member is 0.30 or more. It is 0.45 or less.

The surface layer of the electrophotographic photosensitive member of the present invention is formed of hydrogenated amorphous silicon carbide, and the sum of the atomic densities of silicon atoms and carbon atoms is 6.60 × 10 ²² atoms / cm ³ or higher. By forming the surface layer, it is considered that the bonding force between silicon atoms and carbon atoms forming the skeleton of the film structure is unlikely to be improved and it becomes difficult to obtain a photoconductor excellent in wear resistance.

  In addition to being able to extend the service life due to its excellent wear resistance, it is possible to suppress uneven wear and scratches and maintain a smooth surface over a long period of time. As a result, the inorganic fine powder of the present invention can be held uniformly over a long period of time at the contact portion between the photoreceptor and the cleaning blade, and an appropriate lubricating effect can be maintained over a long period of time.

  At the same time, since the bonding force of the skeleton atoms on the surface layer of the photoreceptor is high and the space ratio is low, the reaction probability between the carbon atom and the oxidizing substance is reduced, and the effect of suppressing the oxidation reaction on the surface of the photoreceptor by the charging means appears. Since the oxidation reaction is suppressed, the generation of polar groups on the surface of the photoconductor is suppressed, the adsorption of moisture and charged products is reduced, and the image that has been eliminated by wearing the surface of the photoconductor until now The flow can be suppressed regardless of wear, and the life of the photoreceptor can be extended.

  By selecting the inorganic fine powder contained in the toner of the present invention from a substance having a Mohs hardness of 4.0 or more and 7.0 or less, the noise and chatter of the cleaning member can be suppressed even in a low temperature and low humidity environment. Long life can be achieved without suppressing photoconductor wear and without causing image defects.

  It is known that a part of the inorganic fine powder on the toner surface is separated from the toner in the development process and the transfer process. The inorganic fine powder released from the toner can act as a lubricant between the cleaning member and the photosensitive member at the nip where the cleaning member and the photosensitive member contact each other, and can exert an effect of blocking the toner to prevent slipping out. it can.

  When the cleaning member is strongly pressed against the surface layer of the photoreceptor excellent in wear resistance of the present invention in order to employ a contact charging device, the inorganic fine powder has a Mohs hardness of less than 4.0. Wears out and the lubricant can no longer function, causing the photoreceptor to squeal or chatter, or the worn inorganic fine powder slips through the cleaning member, making the lubricant unable to function and contaminating the charger. Or may cover the surface of the photoreceptor and cause a decrease in image density.

  Further, if the material has a Mohs hardness of more than 7.0, the force to polish the photoconductor becomes stronger, so that the photoconductor is abraded, and the life is shortened due to the thinning of the film thickness and the occurrence of scratches in the circumferential direction. End up.

  When the inorganic fine powder contained in the toner of the present invention has a primary particle number average particle size of 30 nm to 800 nm, the cleaning member is further prevented from squealing and chattering, and cleaning defects such as toner slipping are also suppressed. Preferably, it is 80 nm or more and 300 nm or less.

  If the number average particle diameter is less than 30 nm, the cleaning member may easily slip through, and the function of the lubricant may not be achieved, causing the photoreceptor to squeal or chatter, or may contaminate the charger. When the number average particle diameter exceeds 800 nm, the toner damming effect at the nip portion is small, and the toner slips easily.

  It is preferable that the inorganic fine powder contained in the toner of the present invention is a substance further containing strontium titanate as a main component. The suppression of noise and chatter of the cleaning member is further improved, and the contamination of the charger is also improved. Although the reason is not clear, it is considered that strontium titanate having a weakly positive charging characteristic has a weak repulsive force against the photosensitive member, and does not easily slip through the cleaning member, and preferably exhibits a lubricating effect.

  The inorganic fine powder contained in the toner of the present invention further contains 50% by number or more of hexahedral particles having ridges and vertices, whereby the effect of scraping off the surface of the photoreceptor is suitably exhibited and the cleaning property. Is further preferable.

  When the ratio of the number of carbon atoms to the sum of the number of silicon atoms and the number of carbon atoms in the surface layer of the electrophotographic photoreceptor of the present invention is 0.61 or more and 0.75 or less, a higher quality image can be obtained. And more preferred.

  When the ratio of the number of carbon atoms to the sum of the number of silicon atoms and carbon atoms is less than 0.61, particularly when hydrogenated amorphous silicon carbide having a high atomic density is formed, the resistance value of silicon carbide decreases. There is a case. When the resistance value is lowered, a lateral flow of the electrostatic latent image occurs. In particular, the image density on the low density side is lowered, and the gradation is lowered. Moreover, when this ratio is larger than 0.75, especially when hydrogenated amorphous silicon carbide having a high atomic density is formed, light absorption in the surface layer may increase rapidly. When the light absorption of the surface layer increases, the photosensitivity of the photoreceptor decreases, and it is necessary to increase the amount of image exposure necessary for forming an electrostatic latent image. In such a case, the photosensitivity changes sensitively to slight variations in the thickness of the surface layer of the photoconductor due to manufacturing or wear, and image density unevenness tends to occur.

  The surface layer of the electrophotographic photosensitive member of the present invention has a ratio of the number of hydrogen atoms to the sum of the number of silicon atoms, the number of carbon atoms, and the number of hydrogen atoms of 0.30 or more and 0.45 or less. In some cases, a higher quality image can be obtained, which is more preferable.

  When the ratio of the number of hydrogen atoms to the sum of the number of silicon atoms, carbon atoms, and hydrogen atoms is less than 0.30, an optical band is formed particularly when hydrogenated amorphous silicon carbide having a high atomic density is formed. The sensitivity may decrease due to the narrowing of the gap and increased light absorption. On the other hand, when this ratio is larger than 0.45, there is a tendency that the number of terminal groups having many hydrogen atoms such as methyl groups increases in the surface layer. When a large number of terminal groups having a plurality of hydrogen atoms are present, a large space is formed in the atomic structure, and a bond is generated in a bond between atoms existing around. Such a structurally weak portion is not only inferior in wear resistance, but also becomes a very weak portion against oxidation, and moisture and charged products are adsorbed to cause image flow.

  The present invention includes a step of charging an electrostatic image carrier with a charging member, an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic image carrier, and a toner carrier. A developing process for transferring the toner to the electrostatic latent image for visualization, a transfer process for transferring the toner image formed on the electrostatic charge image carrier onto a recording medium, and a surface of the electrostatic charge image carrier after the transfer And an image forming method having a cleaning step of cleaning the substrate with a cleaning member.

First, the electrostatic image bearing member of the present invention is an electrophotographic photosensitive member in which at least a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide are sequentially laminated, and an atom of silicon atoms in the surface layer. The sum of the density and the atomic density of carbon atoms is 6.60 × 10 ²² atoms / cm ³ or more.

  FIG. 1 is a view schematically showing an example of an apparatus for depositing a photoconductor by an RF plasma CVD method using a high-frequency power source for producing an a-Si photoconductor of the present invention.

  This apparatus is roughly composed of a deposition apparatus 1100 having a reaction vessel 1110, a raw material gas supply apparatus 1200, and an exhaust device (not shown) for depressurizing the inside of the reaction container 1110.

  A conductive substrate 1112, a conductive substrate heating heater 1113, and a source gas introduction pipe 1114 connected to the ground are installed in the reaction vessel 1110 in the deposition apparatus 1100. Further, a high frequency power source 1120 is connected to the cathode electrode 1111 via a high frequency matching box 1115.

The source gas supply device 1200 includes source gas cylinders 1221 to 1225 such as SiH ₄ , H ₂ , CH ₄ , NO, and B ₂ H ₆ , valves 1231 to 1235, pressure regulators 1261 to 1265, inflow valves 1241 to 1245, and outflow valves. 1251 to 1255 and mass flow controllers 1211 to 1215. A gas cylinder filled with each source gas is connected to a source gas introduction pipe 1114 in the reaction vessel 1110 via an auxiliary valve 1260.

  Next, a method for forming a deposited film using this apparatus will be described. First, the conductive substrate 1112 that has been degreased and washed in advance is placed in the reaction vessel 1110 via a cradle 1123. Next, an exhaust device (not shown) is operated to exhaust the reaction vessel 1110. While viewing the display of the vacuum gauge 1119, when the pressure in the reaction vessel 1110 reaches a predetermined pressure of, for example, 1 Pa or less, power is supplied to the substrate heating heater 1113, and the conductive substrate 1112 is set to, for example, 50 ° C to 350 ° C. To the desired temperature. At this time, an inert gas such as Ar or He can be supplied from the gas supply apparatus 1200 to the reaction vessel 1110 and heated in an inert gas atmosphere.

  Next, a gas used to form a deposited film is supplied from the gas supply device 1200 to the reaction vessel 1110. That is, if necessary, the valves 1231 to 1235, the inflow valves 1241 to 1245, and the outflow valves 1251 to 1255 are opened, and the flow rate is set in the mass flow controllers 1211 to 1215. When the flow rate of each mass flow controller is stabilized, the main valve 1118 is operated while viewing the display of the vacuum gauge 1119 to adjust the pressure in the reaction vessel 1110 to a desired pressure. When a desired pressure is obtained, high frequency power is applied from the high frequency power source 1120 and at the same time, the high frequency matching box 1115 is operated to generate plasma discharge in the reaction vessel 1110. Thereafter, the high frequency power is quickly adjusted to a desired power to form a deposited film.

  When the formation of the predetermined deposited film is finished, the application of high-frequency power is stopped, the valves 1231 to 1235, the inflow valves 1241 to 1245, the outflow valves 1251 to 1255, and the auxiliary valve 1260 are closed, and the supply of the source gas is finished. At the same time, the main valve 1118 is fully opened, and the reaction vessel 1110 is evacuated to a pressure of 1 Pa or less.

  The formation of the deposited layer is completed as described above. When a plurality of deposited layers are formed, the above procedure is repeated again to form each layer. The bonding region can also be formed by changing the raw material gas flow rate, pressure, and the like to the conditions for forming the photoconductive layer in a certain time.

  After all the deposited films are formed, the main valve 1118 is closed, an inert gas is introduced into the reaction vessel 1110 to return to atmospheric pressure, and then the conductive substrate 1112 is taken out.

  The electrophotographic photosensitive member of the present invention has a film structure having a high atomic density by increasing the atomic density of silicon atoms and carbon atoms constituting a-SiC as compared with the surface layer of a conventionally known electrophotographic photosensitive member. Forming a layer.

  When producing an a-SiC surface layer having a high atomic density according to the present invention, it is generally better that the amount of gas supplied to the reaction vessel is smaller, although high-frequency power is higher, depending on the conditions at the time of creating the surface layer. The higher one is better, the higher the pressure in the reaction vessel is, and the higher the temperature of the conductive substrate is.

First, the gas decomposition can be promoted by reducing the amount of gas supplied into the reaction vessel and increasing the high-frequency power. Thereby, a carbon atom supply source (for example, CH ₄ ) that is harder to decompose than a silicon atom supply source (for example, SiH ₄ ) can be efficiently decomposed. As a result, active species having a small number of hydrogen atoms are generated, and the number of hydrogen atoms in the film deposited on the substrate is reduced, so that an a-SiC surface layer having a high atomic density can be formed.

  In addition, by increasing the pressure in the reaction vessel, the residence time of the source gas supplied into the reaction vessel becomes longer, and a weakly bonded hydrogen abstraction reaction occurs due to hydrogen atoms generated by the decomposition of the source gas. Networking of silicon atoms and carbon atoms is promoted.

  Furthermore, by increasing the temperature of the conductive substrate, the surface movement distance of the active species that has reached the conductive substrate becomes longer, and a more stable bond can be created. As a result, the atoms are bonded in a more structurally stable arrangement as the a-SiC surface layer.

  The toner of the present invention is a toner having toner particles containing at least a binder resin and a colorant and inorganic fine powder, and the inorganic fine powder has a Mohs hardness of 4.0 or more and 7.0 or less. To do.

  The method for producing the toner particles is not particularly limited, and the toner particles may be produced by any known method such as suspension polymerization method, emulsion polymerization method, associative polymerization method, kneading and pulverizing method.

  As an example, a method for producing the toner of the present invention in the kneading and pulverizing method will be described.

  In the toner of the present invention, a binder resin, a colorant, other additives and the like are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then a heat kneader such as a heating roll, a kneader, or an extruder is used. Melt-knead, cool and solidify, then pulverize and classify.

  In particular, it is preferable to use a mechanical pulverizer as the pulverizing means used in the toner manufacturing method in which the shape of coarse particles is controlled. Examples of the mechanical pulverizer include a pulverizer inomizer manufactured by Hosokawa Micron Corporation, a pulverizer KTM manufactured by Kawasaki Heavy Industries, Ltd., and a turbo mill manufactured by Turbo Industry Co., Ltd. It is preferable to use these apparatuses as they are or after being appropriately modified.

  Further, the inorganic fine powder having a Mohs hardness of 4.0 or more and 7.0 or less and, if necessary, a desired additive are sufficiently mixed by a mixer such as a Henschel mixer to produce the powder. Alternatively, mixing can be externally added at any time after the production of the toner particles. For example, it can be externally added to the toner in the step of classifying or spheroidizing the toner particles.

  As another example, a method for producing the toner of the present invention in the suspension polymerization method will be described.

  First, a low softening point substance, a polar resin, a colorant, a charge control agent, a polymerization initiator, and other additives were added to the polymerizable monomer and dissolved or dispersed uniformly by a homogenizer, an ultrasonic disperser, or the like. The monomer system is dispersed in an aqueous phase containing a dispersion stabilizer by a usual stirrer, homogenizer, homomixer or the like.

  At this time, granulation is preferably performed by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size. Thereafter, stirring may be carried out to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer.

  The polymerization temperature is preferably set to 40 ° C. or higher, and generally 50 ° C. or higher and 90 ° C. or lower. In addition, the temperature may be raised in the latter half of the polymerization reaction, and in order to remove unreacted polymerizable monomers, by-products and the like that cause odors during toner fixing, the temperature may be increased in the latter half of the reaction or at the end of the reaction. The partial aqueous medium may be distilled off.

  After completion of the reaction, the produced toner particles are washed, collected by filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer system.

  Toner particle size distribution control and particle size control are carried out by adjusting the pH of the system during granulation, by changing the type and amount of a sparingly water-soluble inorganic salt and a dispersant that acts as a protective colloid, and mechanical equipment conditions. For example, it can be performed by controlling the stirring conditions such as the peripheral speed of the rotor, the number of passes, the shape of the stirring blade, the shape of the container or the solid content concentration in the aqueous solution.

  The toner particles prepared by the above method are classified as necessary. Hereinafter, similarly to the kneading and pulverizing method, the inorganic fine powder having a Mohs hardness of 4.0 or more and 7.0 or less, and a desired particle if necessary. The additive is prepared by sufficiently mixing with a mixer such as a Henschel mixer.

  The toner of the present invention may be produced by any method regardless of the method described above, but has at least an inorganic fine powder having a Mohs hardness of 4.0 or more and 7.0 or less.

  Examples of the inorganic fine powder include zinc oxide (Mohs hardness, hereinafter the same: 4 to 5), cerium oxide (6 to 7), iron oxide (6), zirconium oxide (7), chromium dioxide (6 to 7), Metal oxides such as trimanganese tetraoxide (4) and tin oxide (6 to 7), composite metal oxides such as strontium titanate (5 to 6), metal salts such as magnesium carbonate (4), apatite (5 ) And the like, and silicic acid compounds such as silica (7) and the like.

  The method for selecting and adjusting the inorganic fine powder is not particularly limited as long as it is within the scope of the present invention. Two or more different substances may be selected together, or the same substances with different particle sizes may be selected together. The same substances with different shapes may be mixed, or those with different adjustment methods may be mixed.

  The inorganic fine powder contained in the toner of the present invention preferably has a number average particle diameter of 30 nm to 800 nm.

  As for the number average particle diameter of the inorganic fine powder in the present invention, 100 samples are randomly taken from a photograph taken with an electron microscope at a magnification of 50,000 times, and for spherical particles, the diameter, elliptical sphere, or For rectangular parallelepiped particles, the average value of the short diameter and the long diameter, and for the plate-shaped particles, the average value of the long side and the short side as viewed from the plane direction is used as the particle diameter of the particles, and the average value of them is determined. The average was obtained as the diameter.

  A preferable content of the inorganic fine powder contained in the toner of the present invention is 0.01 part by mass or more and 5.0 part by mass or less, more preferably 0.05 part by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the toner particles. 0.0 parts by mass or less.

  By setting the content of the inorganic fine powder within the above range, the liberated amount of the inorganic fine powder released from the toner becomes a preferable range for expressing the effects of the present invention.

  The particle shape of the inorganic fine powder may be any of spherical shape, grape shape, needle shape, polyhedron, plate shape, etc., but particles having a hexahedral particle shape that is a convex polyhedron surrounded by six squares When it contains, it is thought that the vertex and the ridgeline are improving the cleaning property, and it is more preferable.

  Since 50% by number or more of the inorganic fine powder has a hexahedral particle shape, the cleaning performance is particularly excellent, and the effects of the present invention are more suitably exhibited.

  The inorganic fine powder particles may be further hydrophobized. By subjecting the inorganic fine powder particles to a hydrophobization treatment, it may be possible to suppress fluctuations in the triboelectric charge amount due to the environment. Examples of the hydrophobic treatment agent include a treatment agent such as a coupling agent, silicone oil, and fatty acid metal salt.

  For example, in the case of a coupling agent which is a compound having a hydrophilic group and a hydrophobic group, the hydrophilic group side covers the surface of the inorganic fine powder so that the hydrophobic group side becomes the outside, and the inorganic fine powder is hydrophobized.

  In addition, in the case of the hydrophobizing agent as described above, the shape of the inorganic fine powder is hardly changed due to the surface treatment at the molecular level, and the effect of the cubic or cuboid shape is maintained. More preferred.

  Examples of coupling agents include titanate, aluminum, and silane coupling agents. Examples of fatty acid metal salts include zinc stearate, sodium stearate, calcium stearate, zinc laurate, aluminum stearate, and magnesium stearate. The same effect can be obtained with stearic acid, which is a fatty acid.

  As a treatment method, a hydrophobization treatment agent or the like is dissolved and dispersed in a solvent, an inorganic fine powder is added therein, and the solvent is removed while stirring. Examples thereof include a dry method in which a salt and an inorganic fine powder are directly mixed and treated with stirring.

  Further, regarding the hydrophobization treatment, it is not necessary to completely treat and coat the inorganic fine powder, and the inorganic fine powder may be exposed as long as the effect is obtained. That is, the surface treatment may be formed discontinuously.

  In addition to the inorganic fine powder contained in the toner of the present invention, as other external additives, inorganic oxides such as silica, alumina and titanium oxide, inorganic fine powder having a fine particle size such as carbon black and carbon fluoride are used as toner particles. It may be added externally. These impart fluidity and chargeability to the toner.

  If the silica fine powder, alumina fine powder or titanium oxide fine powder dispersed on the surface of the toner particles are fine particles, these fine powders have a high fluidity-imparting effect. Therefore, these fine powders are preferably fine particles. . The number average particle diameter of these fine powders is preferably 5 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less.

  A preferable addition amount of these inorganic fine powders is 0.03 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the toner particles. When the added amount of the inorganic fine powder is less than 0.03 parts by mass, sufficient fluidity imparting effect cannot often be obtained. On the other hand, when the amount exceeds 5 parts by mass, the toner is easily tightened, and a large amount of excess external additive is liberated, which tends to have an adverse effect.

  There is no particular limitation on the electrophotographic apparatus on which the toner of the present invention and the electrophotographic photosensitive member are mounted. Even in the conventional electrophotographic apparatus shown in FIG. 2, the conventional toner has high humidity control and wear resistance. In addition, a better effect than that of the electrophotographic photosensitive member can be obtained.

  Furthermore, the present invention employs a contact charging member as shown in FIG. 3, for example. Even if the cleaning member is strongly pressed against the photosensitive member to prevent contamination of the charging member with residual transfer toner, the cleaning member squeals and chatters. Thus, the charging member and the power supply unit can be downsized. Therefore, it is possible to provide an image forming apparatus having a longer life and lower power than the conventional electrophotographic apparatus.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

(Photoconductor Production Examples D1 to 11)
Using a plasma processing apparatus using a high-frequency power source in the RF band as shown in FIG. 1, on a cylindrical substrate (cylindrical aluminum substrate with a diameter of 84 mm, a length of 381 mm, and a thickness of 3 mm). A positively charged a-Si photoreceptor was prepared. At that time, the charge injection blocking layer, the photoconductive layer, and the surface layer are formed in this order, and the gas type and flow rate, internal pressure, high-frequency power, substrate temperature, and film thickness at the time of forming each layer are set as the conditions shown in Table 1. Photoconductors D1 to D11 were produced. Two electrophotographic photoreceptors were produced under each film forming condition.

  For each of the two electrophotographic photosensitive members produced under the respective film formation conditions, the ratio of the number of carbon atoms to the sum of the number of silicon atoms and the number of carbon atoms (hereinafter referred to as the number of carbon atoms) , C / (Si + C)), atomic density of silicon atoms (referred to as Si atom density), atomic density of carbon atoms (referred to as C atom density), and sum of Si atom density and C atom density (hereinafter referred to as C atom density) The ratio of the number of hydrogen atoms to the sum of the number of silicon atoms, the number of carbon atoms and the number of hydrogen atoms (hereinafter referred to as the “H atom ratio”). (Referred to as H atom density) was determined by the analysis method described below.

  Then, with another electrophotographic photosensitive member, evaluation of gradation property, sensitivity, squeal / chatter 1, cleaning property, image flow, abrasion resistance, squeeze / chatter evaluation 2 under the evaluation conditions described later. Evaluation was performed. These results are shown in Table 2.

(Measurement of C / (Si + C), Si + C atom density, H atom ratio)
First, a reference electrophotographic photosensitive member in which only the charge injection blocking layer and the photoconductive layer shown in Table 1 were laminated was prepared, and a central portion in the longitudinal direction in an arbitrary circumferential direction was cut out by 15 mm □ to prepare a reference sample. Next, an electrophotographic photosensitive member in which the charge injection blocking layer, the photoconductive layer, and the surface layer were laminated was similarly cut out to prepare a measurement sample. The reference sample and the measurement sample were measured by spectroscopic ellipsometry (manufactured by JA Woollam: high-speed spectroscopic ellipsometry M-2000) to determine the film thickness of the surface layer.

  Specific measurement conditions of spectroscopic ellipsometry are incident angles: 60 °, 65 °, 70 °, measurement wavelengths: 195 nm to 700 nm, and beam diameter: 1 mm × 2 mm.

  First, the relationship between the wavelength, the amplitude ratio Ψ, and the phase difference Δ was determined for each reference angle of the reference sample by spectroscopic ellipsometry.

  Next, using the measurement result of the reference sample as a reference, the relationship between the wavelength, the amplitude ratio Ψ, and the phase difference Δ was determined at each incident angle by spectroscopic ellipsometry, similarly to the reference sample.

  Then, a charge injection blocking layer, a photoconductive layer, and a surface layer are sequentially laminated, and a layer structure having a roughness layer with a surface layer and an air layer swallowing volume ratio of 8: 2 on the outermost surface is used as a calculation model. Software: The relationship between the wavelength at each incident angle and Ψ and Δ was calculated by WVASE 32. Furthermore, the film thickness of the surface layer when the mean square error of the relationship between the wavelength, Ψ and Δ obtained by measuring the measurement sample and the relationship between the wavelength, Ψ and Δ obtained by this calculation is minimized is calculated. This value was taken as the film thickness of the surface layer.

  After the measurement by spectroscopic ellipsometry is completed, the above measurement sample is subjected to RBS (Rutherford backscattering method) (manufactured by Nissin High Voltage Co., Ltd .: backscattering measuring device AN-2500) and silicon atoms and carbon atoms in the surface layer. The number of atoms was measured, and C / (Si + C) was determined. Next, the atomic density of silicon atoms, the atomic density of carbon atoms, and the Si + C atomic density are determined using the measured number of atoms of silicon and carbon atoms, RBS measurement area, and the thickness of the surface layer determined by spectroscopic ellipsometry. It was.

  Simultaneously with RBS, the number of hydrogen atoms in the surface layer of the measurement sample was measured by HFS (hydrogen forward scattering method) (manufactured by Nisshin High Voltage Co., Ltd .: backscattering measurement device AN-2500). The H atom ratio was determined from the number of hydrogen atoms determined by HFS, the number of silicon atoms and the number of carbon atoms determined by RBS. Next, the atomic density of hydrogen atoms was determined using the number of hydrogen atoms measured, the HFS measurement area, and the surface layer thickness determined by spectroscopic ellipsometry.

Specific measurement conditions for RBS and HFS are incident ion: 4He ⁺ , incident energy: 2.3 MeV, incident angle: 75 °, sample current: 35 nA, incident beam length: 1 mm, and the detector of RBS is scattered. Angle: 160 °, aperture diameter: 8 mm, HFS detector measured with recoil angle: 30 °, aperture diameter: 8 mm + Slit.

(Inorganic fine powder production example B1)
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 be 0.5 mol / L in terms of SrTiO ₃ . The slurry was heated to 83 ° C. at 6.5 ° C./hour in a nitrogen atmosphere, and reacted for 5.5 hours after reaching 83 ° C. After the reaction, the mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.

  Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 6.5% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous zinc sulfate solution is added dropwise to the surface of the perovskite crystal. Zinc acid was precipitated. The slurry was repeatedly washed with pure water and then filtered with Nutsche, and the resulting cake was dried and surface-treated with zinc stearate. The particle shape of all particles was approximately cubic or cuboid hexahedral, and the number average particle Strontium titanate having a diameter of 110 nm was obtained. This strontium titanate is designated as inorganic fine powder B1.

(Toner Production Example T1)
Styrene-butyl acrylate copolymer (peak molecular weight 19 million, Mw = 280,000, Mn = 0,000, Tg = 56 ° C.) 100 parts by mass magnetite (octahedron, average particle size 0.21 μm, coercive force 11 0.5 KA / m, residual magnetization 10.8 Am ² / kg, saturation magnetization 82.1 Am ² / kg) 90 parts by mass polyethylene wax (Mn = 850, melting point: 107 ° C., penetration at 25 ° C .: 1)
4 parts by mass charge control agent (aluminum salicylate compound, structure is shown below) 2 parts by mass

  The above materials were sufficiently premixed with a Henschel mixer and then melt-kneaded with a twin-screw kneading extruder set at 130 ° C. The obtained kneaded product is cooled, coarsely pulverized with a cutter mill, then finely pulverized using a fine pulverizer using a jet stream, and the resulting finely pulverized product is further classified with an air classifier, and the mass average particle A classified fine powder having a diameter (D4) of 7.5 μm was obtained.

  The weight average particle diameter (D4) of the toner is calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

  The specific measurement method is as follows.

  (1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.

  (2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.

  (3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.

  (4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

  (5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

  (6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.

  (7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4).

To 100 parts by mass of the obtained classified fine powder, 1 part by mass of the inorganic fine powder B1 (hexahedral strontium titanate, number average particle size 110 nm), and further silica fine powder (BET specific surface area 200 m ² ) produced by a dry method. / G) 1 part by weight of hydrophobic silica treated with 16 parts by weight of amino-modified silicone oil (amine equivalent 830, kinematic viscosity at 25 ° C. 70 × 10 ⁻⁶ m ² / s) per 100 parts by weight, and stirring blade rotation speed Using a Henschel mixer FM500 (manufactured by Mitsui Miike Co., Ltd.) at 1100 rpm, it was rotated for 4 minutes and externally added, and sieved with a mesh having a mesh size of 150 μm to obtain magnetic one-component toner T1.

(Inorganic fine powder production example B2)
Dissolve titanyl sulfate powder in distilled water, and add sulfuric acid and distilled water so that the Ti concentration in the solution is 1.5 (mol / l) and the acid concentration at the end of the reaction is 2.0 (mol / l). The added solution was prepared, and this solution was subjected to a hydrolysis reaction at 110 ° C. for 36 hours in a sealed container to carry out a hydrolysis reaction. Thereafter, washing with water was performed to sufficiently remove sulfuric acid and impurities to obtain a metatitanic acid slurry. To this slurry, strontium carbonate (average particle diameter of 80 nm) is added so as to have an equimolar amount with respect to titanium oxide. After thorough mixing in an aqueous wet, washed, dried, sintered at 800 ° C. for 3 hours, and subjected to mechanical pulverization and classification to obtain spherical strontium titanate having a number average particle size of 100 (nm). . This strontium titanate is designated as inorganic fine powder B2.

(Inorganic fine powder production example B3)
Magnesium vapor pressure of 0.04 atm is introduced by distilling and purifying magnesium metal, heating and evaporating high-purity magnesium at 1150 ° C and introducing it into the oxidation reactor, and introducing 99.9% pure argon gas as a diluent. Then, oxidation was performed at a temperature of 1000 ° C. while introducing oxygen gas having a purity of 99.9%. The produced magnesia fine particles were circulated during oxidation, and melt-grown in an oxidation flame to obtain a magnesium oxide (MgO) powder having a number average particle diameter of 200 nm manufactured by a gas phase oxidation reaction method. This magnesium oxide particle is referred to as inorganic fine powder B3.

(Inorganic fine powder production example B4)
A stirrer, a dropping funnel and a thermometer were set in a glass reactor, and ammonia water was added to ethanol and stirred, and kept at 25 ° C. Next, tetraethoxysilane was dropped into the solution for 60 minutes to react. After completion of the dropping, stirring was further continued at 25 ° C. for 3 hours to obtain a silica sol suspension. Next, this silica sol suspension was heated to remove ethanol, and then toluene was added and further heated to remove water. Next, 3 parts by mass of methylsilane was added to the silica particles in the suspension, and the mixture was reacted at 80 ° C. for 1 hour to hydrophobize the silica. Thereafter, the suspension was heated to remove toluene, dried with a fluid bed dryer, and then pulverized with a pin mill. Then, after quickly dispersing again in the toluene solution, 10 parts by mass of hexamethyldisilazane is added and sufficiently stirred. Then, after drying at 110 degreeC using a fluidized bed dryer, it fully pulverized with a pin mill and obtained spherical sol-gel silica having a number average particle diameter of 110 nm. This silica particle is designated as inorganic fine powder B4.

(Inorganic fine powder production example B5)
A mixed gas having a volume ratio of argon and oxygen of 3: 1 is introduced into the reaction vessel to replace the atmosphere. Oxygen gas is supplied into this reaction vessel at 40 (m ³ / hr) and hydrogen gas at 20 (m ³ / hr), and an ignition device is used to form a combustion flame composed of oxygen-hydrogen. Next, a metal silicon powder as a raw material is charged into the combustion flame with a hydrogen carrier gas having a pressure of 12 kg / cm ³ to form a dust cloud. This dust cloud is ignited by a combustion flame and causes an oxidation reaction by dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled to obtain spherical silica fine powder having a number average particle size of 730 (nm). This silica particle is designated as inorganic fine powder B5.

(Inorganic fine powder production example B6)
A fine spherical silica powder having a number average particle size of 920 (nm) was obtained in the same manner as in the fine inorganic powder production example B5 except that the carrier gas pressure was 9 kg / cm ^{3 in the} fine inorganic powder production example B5. . This silica particle is designated as inorganic fine powder B6.

(Inorganic fine powder production example B7)
Open the flammable gas supply pipe to supply oxygen gas to the burner, ignite the ignition burner, then open the flammable gas supply pipe to supply hydrogen gas to the burner to form a flame, and form tetrachloride Silicon was gasified with an evaporator and supplied to perform a flame hydrolysis reaction, and the generated silica powder was recovered. Using 100 parts by mass of the obtained silica fine powder, this was put in a mixer, 20 parts by mass of 50 mm 2 / s dimethyl silicone oil was added dropwise with stirring in a nitrogen atmosphere, and the mixture was heated and stirred at 300 ° C. for 1 hour, followed by cooling. Then, it was sufficiently crushed by a pin mill to obtain spherical silica fine powder having a number average particle size of 22 (nm). This silica particle is designated as inorganic fine powder B7.

(Inorganic fine powder production example B8)
Commercially available natural mica fine particles (5 μm) were sufficiently milled with a jet mill and classified and collected with a cyclone to obtain plate-like mica fine powder having a number average particle size of 280 (nm). This mica particle is designated as inorganic fine powder B8.

(Inorganic fine powder production example B9)
Commercially available natural talc fine particles (2 μm) were sufficiently milled by a jet mill and classified and collected by a cyclone to obtain a plate-like talc fine powder having a number average particle size of 330 (nm). This talc particle is designated as inorganic fine powder B9.

(Inorganic fine powder production example B10)
SiCl ₄ was dispersed in an organic solvent and maintained at 25 ° C. NH ₃ was blown into this, and the reaction product was filtered and washed to obtain silicon diimide. The obtained silicon diimide was calcined at 950 ° C. to obtain amorphous silicon nitride powder. The amorphous silicon nitride powder is crystallized by heating to 1350 ° C. in a nitrogen gas stream, and then pulverized to further form an amorphous silicon nitride fine powder having a number average particle size of 80 nm. Got.

  This was washed, filtered, dried, and crushed by ordinary methods to obtain silicon nitride fine particles. The silicon nitride fine particles are referred to as inorganic fine powder B10.

(Toner Production Examples T2 to T10)
Toners T2 to T10 were obtained in the same manner as in Toner Production Example T1, except that the inorganic fine powder B1 to be added was changed to B2 to B10 as shown in Table 2.

<Example 1>
Using the photoreceptor D1 and the toner T1, a paper passing durability test was performed in a mono-color mode using an apparatus obtained by modifying the primary charging device and the photoreceptor cleaning device of a Canon laser copying machine iRC6800.

  The primary charging member used in this experiment has an elastic layer in which conductive carbon is dispersed in urethane rubber, EPDM, or the like having a thickness of 3 mm on a peripheral surface of a core metal having a diameter of 6 mm. In addition, a surface layer in which conductive carbon is added to a mixed resin of polytetrafluoroethylene resin and acrylic resin is coated on the surface. The overall shape is a roller shape having an outer diameter of 12 mm and a longitudinal length of 320 mm. The roller is in contact with the photoreceptor at an intrusion amount of 0.5 mm, is attached so as to be driven and rotated by the photoreceptor, and a predetermined primary charging bias is applied. .

  In the contact charging method, there is known a method of preventing the charging member from being contaminated by providing a cleaning member such as a cleaning brush or a flocking roller on the charging member. No cleaning member is provided.

  Further, in the photoconductor cleaning device used in this experiment, the cleaning blade is a plate blade made of urethane rubber (hardness 65 °) with a thickness of 3.0 mm, and the contact pressure with the photoconductor is 23 ° C./50%. It was set to 0.45 N / cm under the environment. The contact pressure between the cleaning blade and the photosensitive member is generally set in the range of 0.1 N / cm to 0.5 N / cm in consideration of toner slipping and damage to the blade tip. 0.45 N / cm is a strong setting.

  First, in an environmental test room where the indoor temperature and humidity can be adjusted, the photoconductor heater is always turned on in an environment where the indoor temperature / humidity is set to 23 ° C./50%, and the gradation of the photoconductor, And the sensitivity was evaluated.

(Gradation evaluation)
First, the entire gradation range is defined by an area gradation (that is, an area gradation of a dot portion where image exposure is performed) using an area gradation dot screen at a line density of 45 degrees 170 dpi (170 lines per inch) by image exposure light. The gradation data is distributed evenly in 17 steps. At this time, the darkest gradation is set to 16, the thinnest gradation is set to 0, and a number is assigned to each gradation to make a gradation step.

  Next, the electrophotographic photosensitive member produced in the electrophotographic apparatus is installed, and the gradation data is output to A3 paper using the text mode of the electrophotographic apparatus. At this time, if high-humidity flow occurs, the evaluation of the gradation property is affected. Therefore, as described above, the photosensitive member heater is always turned on, and the surface of the electrophotographic photosensitive member is maintained at about 40 ° C. The image density of the obtained image is measured with a reflection densitometer (manufactured by X-Rite Inc: 504 spectral densitometer) for each gradation.

The correlation coefficient between the evaluation value obtained in this way and the gradation stage is calculated, and from the correlation coefficient = 1.00 when the gradation expression in which the reflection density of each gradation changes completely linearly is obtained. The difference of was calculated. And film-forming conditions No. The ratio of the difference calculated from the correlation coefficient of the electrophotographic photosensitive member manufactured under each film forming condition with respect to the difference calculated from the correlation coefficient of the electrophotographic photosensitive member manufactured in Step 1 is evaluated as an index of gradation. did. In this evaluation, the smaller the numerical value, the better the gradation, indicating that the gradation expression is linear. In the reflection density measurement, three images were output for each gradation, and the average value of the densities was used as the evaluation value. This result was evaluated as a three-step evaluation as follows, and A to B were set as acceptable. The evaluation results are shown in Table 2.
A ... Film formation condition No. 1. Correlation coefficient calculated from the correlation coefficient of the electrophotographic photosensitive member prepared in Step 1 = correlation coefficient calculated from the electrophotographic photosensitive member manufactured under each film forming condition with respect to the difference from 1.00 = 1. The gradation ratio is good when the ratio of the difference from 00 is 1.80 or less.
B ... Film formation condition No. 1. Correlation coefficient calculated from the correlation coefficient of the electrophotographic photosensitive member prepared in Step 1 = correlation coefficient calculated from the electrophotographic photosensitive member manufactured under each film forming condition with respect to the difference from 1.00 = 1. There is no practical problem with the ratio of the difference from 00 exceeding 1.80 and less than 2.20.
C: Film formation condition No. 1. Correlation coefficient calculated from the correlation coefficient of the electrophotographic photosensitive member prepared in Step 1 = correlation coefficient calculated from the electrophotographic photosensitive member manufactured under each film forming condition with respect to the difference from 1.00 = 1. The difference ratio from 00 exceeds 2.20, which is a practical problem.

(Sensitivity evaluation)
With the image exposure turned off, the current supplied to the charger was adjusted by an external power source connected to the primary charging roller to set the surface potential of the electrophotographic photosensitive member to 400V.

  Next, image exposure was performed in a state of being charged under the previously set charging condition, and the potential at the developing unit was set to 100 V by adjusting the irradiation energy.

The image exposure light source of the electrophotographic apparatus used for sensitivity evaluation is a semiconductor laser having an oscillation wavelength of 658 nm. The evaluation results are as follows. The results are shown in a relative comparison in which the irradiation energy when the electrophotographic photosensitive member No. 6 is mounted is set to 1.00, and the results are evaluated in three stages as follows, and A to B are passed. The evaluation results are shown in Table 2.
A ... Film formation condition No. The ratio of the irradiation energy to the irradiation energy of the electrophotographic photosensitive member No. 6 is excellent at less than 1.10.
B ... Film formation condition No. The ratio of the irradiation energy to the irradiation energy in the electrophotographic photosensitive member prepared in No. 6 is 1.10 or more and less than 1.15, and there is no practical problem.
C: Film formation condition No. The ratio of the irradiation energy to the irradiation energy of the electrophotographic photosensitive member No. 6 is 1.15 or more, which is a practical problem.

  Next, after the photoconductor heater was always turned off, the temperature / humidity of the environmental test chamber was gradually changed to 12.5 ° C./10% RH over 15 hours. With the photoconductor heater set to OFF at all times, using an A4 black and white document with a printing area of 2%, a 5000 sheet endurance is performed in an intermittent operation in which the rotation of the photoconductor is stopped for 5 seconds each time two sheets are passed. Went. After the completion of the sheet passing, the sheet was left as it was in an environment of 12.5 ° C./10% RH for 15 hours, and 5000 sheets were again passed through the same intermittent operation.

  Evaluation of the squeal and chatter of the photosensitive member (1) was performed in the durable paper passing under the low temperature / low humidity environment. The noise and chatter of the photoconductor is likely to occur in a low temperature environment where the elasticity of the cleaning blade is lower than that at normal temperature. For this reason, the photosensitive member heater is always set to be off as described above. However, if a high humidity flow is generated by turning off the photosensitive member heater, the image evaluation is affected.

(Evaluation of squeal and chatter of photoconductor 1)
If the photosensitive member squeals or chatters, the user will know it as an abnormal sound, and if it deteriorates, the cleaning blade will be damaged or the cleaning will be defective, resulting in a print image defect.

As a method for evaluating the noise and chatter of the photoconductor, when the photoconductor is started and stopped during intermittent paper feeding, especially after being left in a 12.5 ° C / 10% environment and starting from a cold state, It was checked whether or not there was a sound that was anxious from the photoconductor, the result was evaluated as follows, and the results from A to C were accepted. The evaluation results are shown in Table 2.
A: No squeal or chatter on the photoconductor is observed.
B: A very small sound that was not noticed was observed with very little frequency.
C: A small sound that was not usually noticed was observed with a small frequency.
D: A sound that was so small that it was not normally noticed was observed, or a sound that was anxious regardless of frequency.
E. Image defect caused by squealing and chattering.

  Next, after the photoconductor heater was always turned on, the temperature / humidity of the environmental test chamber was gradually changed to 32.5 ° C./80% RH over 15 hours. Here, an A3 character chart (4 pt, printing rate 4%) serving as a reference for image flow evaluation was printed.

  Next, the photosensitive drum heater was always turned off, and 5000 sheets were passed through in the same intermittent operation as at low temperatures. After the paper was passed, the power was turned off and left as it was for 60 hours in an environment of 32.5 ° C./80% RH. Then, the photosensitive member heater was turned off and the A3 character chart was printed again.

  In this high-temperature / high-humidity environment, image flow was evaluated using A3 character charts before and after standing. By turning off the photoconductor heater, which is effective in preventing image flow under high temperature / high humidity, image flow is likely to occur.

(Image flow evaluation)
The images output before the 5000 sheet pass test and the images output after leaving for 60 hours were digitized into PDF files using Canon's digital electrophotographic device iRC-5870 under binary conditions of 300 dpi monochrome. . The black ratio of the image area (251.3 mm × 273 mm) for one round of the electrophotographic photosensitive member was measured using Adobe Photoshop (manufactured by Adobe) for the digitized image. Next, the ratio of the black ratio of the image output after the continuous paper passing test to the image output before the continuous paper passing durability was obtained, and the durability flow was evaluated.

When the endurance flow occurs, characters are blurred in the entire image, or white characters are lost without being printed, so the black ratio in the output image is reduced when compared with a normal image before the continuous paper passing test. To do. Therefore, as the ratio of the black ratio of the image output after the continuous paper test to the normal image before the continuous paper test is closer to 100%, the high-humidity flow becomes better. The results were evaluated as follows in five stages, and A to C were regarded as having the effect of the present invention and passed. The evaluation results are shown in Table 2.
A. The black ratio of the image output after the continuous paper passing test with respect to the image before the continuous paper passing test is particularly excellent at 95% or more and 105% or less.
B. The black ratio of the image output after the continuous paper passing test to the image before the continuous paper passing test is excellent at 85% or more and less than 95%.
C: The black ratio of the image output after the continuous paper feeding test to the image before the continuous paper feeding test is good at 75% or more and less than 85%.
D: There is no problem in practical use because the black ratio of the image output after the continuous paper test to the image before the continuous paper test is 65% or more and less than 75%.
E: The black ratio of the image output after the continuous paper test to the image before the continuous paper test is less than 65%, which is not good.

  Next, the temperature / humidity of the environmental test chamber was gradually changed to 23 ° C./50% RH over 15 hours with the photoconductor heater always set to OFF, and then using an A4 monochrome document with a printing rate of 1%, The continuous paper feed durability of 25,000 sheets per day was carried out for 10 days and up to 250,000 sheets.

  The durability until the end of the continuous paper passing was evaluated for the abrasion resistance and cleaning property of the photoreceptor.

(Abrasion resistance evaluation)
The abrasion resistance evaluation method is as follows. The film thickness of the electrophotographic photosensitive member surface layer immediately after production and after the end of durability is determined by measuring nine points in the longitudinal direction in the arbitrary circumferential direction of the electrophotographic photosensitive member (the center in the longitudinal direction of the electrophotographic photosensitive member). As a reference, 0 points, ± 50 mm, ± 90 mm, ± 130 mm, ± 150 mm) and 9 points in the longitudinal direction at a position rotated by 180 ° from the arbitrary circumferential direction, a total of 18 points were measured, and the average value of the 18 points Calculated by

  The measurement method irradiates light perpendicularly on the surface of the electrophotographic photosensitive member with a spot diameter of 2 mm, and performs spectroscopic measurement of reflected light using a spectrometer (manufactured by Otsuka Electronics: MCPD-2000). The surface layer thickness was calculated based on the obtained reflection waveform. At this time, the wavelength range was 500 nm to 750 nm, the refractive index of the photoconductive layer was 3.30, and the refractive index of the surface layer was a value obtained from the spectroscopic ellipsometry measurement performed during the Si + C atom density measurement described above. .

Measure the film thickness of the electrophotographic photoreceptor immediately after fabrication, attach it to the image forming device, use it for a series of durability tests, take it out from the image forming device, and measure the film thickness at the same position as the measurement immediately after creation. The film thickness of the surface layer after the continuous paper feeding test is calculated in the same manner as immediately after. And a difference is calculated | required from the average film thickness of the surface layer obtained immediately after preparation and after a continuous paper-passing test, and the amount of wear in 265,000 sheets is calculated. And film-forming conditions No. The ratio of the difference in the average film thickness of the surface layer of each electrophotographic photosensitive member to the difference in the average film thickness of the surface layer obtained immediately after the production of the electrophotographic photosensitive member 6 and after the continuous paper passing test is obtained, and the relative evaluation is performed. went. The results were evaluated as follows in five stages, and A to C were regarded as having the effect of the present invention and passed. The evaluation results are shown in Table 2.
A ... Film formation condition No. The difference ratio of the average film thickness of the electrophotographic photosensitive member surface layer produced under each film forming condition with respect to the difference of the average film thickness of the electrophotographic photosensitive member surface layer of No. 6 is 60% or less and particularly excellent wear resistance. Have.
B ... Film formation condition No. The difference ratio of the average film thickness of the electrophotographic photosensitive member surface layer produced under each film forming condition with respect to the difference in the average film thickness of the electrophotographic photosensitive member surface layer of No. 6 is excellent at 60% to 75% or less.
C: Film formation condition No. The difference ratio of the average film thickness of the electrophotographic photosensitive member surface layer produced under each film forming condition to the difference in the average film thickness of the electrophotographic photosensitive member surface layer of No. 6 is good when it is greater than 75% and not more than 90%.
D ... Film formation condition No. The difference ratio of the average film thickness of the electrophotographic photosensitive member surface layer produced under each film forming condition with respect to the difference in the average film thickness of the electrophotographic photosensitive member surface layer of No. 6 is 90% to 100% and there is no practical problem. .
E ... Film formation condition No. The difference ratio of the average film thickness of the electrophotographic photosensitive member surface layer produced under each film forming condition with respect to the difference in the average film thickness of the electrophotographic photosensitive member surface layer of 6 is greater than 100%, which is not good.

(Evaluation of poor cleaning)
As an evaluation method for defective cleaning, check for occurrence of vertical streaks and chatter marks due to defective cleaning on images during intermittent paper passing, and check the surface contamination of the charging roller with toner or inorganic fine powder after completion of durable paper passing. As described below, a five-step evaluation was made, and A to C were accepted. The evaluation results are shown in Table 2.
A. Image defects due to poor cleaning are not observed through the endurance of paper passing, and the state of contamination of the charging roller after completion of the endurance paper passing is also good.
B. Image defects due to poor cleaning are not observed through endurance of paper passing, but slight contamination is seen on the charging roller after completion of endurance paper passing.
C: No image defect due to poor cleaning is observed through the endurance of the paper passing, but the charging roller after the end of the end of the paper passing is contaminated.
D. There was a slight image defect due to poor cleaning in the paper passing durability.
E. There was an image defect due to poor cleaning in the paper passing durability.

  Next, the photoconductor subjected to the abrasion resistance evaluation is returned to the image forming apparatus, and the photoconductor heater is always set to OFF, and an A5 original with a printing rate of 4% is used in an environment of 23 ° C./50% RH. Printing was performed on the back half of the long side of the paper, and the front half was used as a non-printing portion, and 25,000 sheets per day were continuously worn for 10 days, up to 250,000 sheets.

  Evaluation of the squealing and chattering of the photosensitive member (2) was performed by continuous paper passing under this severe condition. Since there is no printing on the photosensitive member without a document and the half of the longitudinal direction of the cleaning blade, the toner and inorganic fine powder contained in the toner are not replenished to the nip portion of the cleaning blade, so that the inorganic fine powder is consumed or lost. If this is the case, the cleaning blade will run out of lubricant. In the image forming apparatus used in this evaluation, the toner collected by the cleaning unit is sent to the back side and collected, and the collected toner is not circulated to the front side in the cleaning unit. It is considered that the inorganic fine powder having a low Mohs hardness is worn away and disappears, and in the photoreceptor having a low atomic density on the surface, the inorganic fine powder slips through a minute groove cut by the inorganic fine powder.

(Evaluation of squeal and chatter of photoconductor 2)
Similar to the evaluation (1) of the squeal and chatter of the photoconductor, it is checked whether there is a sound that is worrisome from the photoconductor, and the result is evaluated as the following five-step evaluation. did. The evaluation results are shown in Table 2.
A: No squeal or chatter on the photoconductor is observed.
B: A very small sound that was not noticed was observed with very little frequency.
C: A small sound that was not usually noticed was observed with a small frequency.
D: A sound that was so small that it was not normally noticed was observed, or a sound that was anxious regardless of frequency.
E ... Image defect caused by squealing or chattering, or cleaning blade turned over, making cleaning impossible.

<Examples 2 to 10 , Reference Examples 1 to 5, and Comparative Examples 1 to 5>
Examples 2 to 10, Reference Examples 1 to 5 and Comparative Example were the same as Example 1 except that the photosensitive member and toner used were changed to D1 to D11 and T1 to T10, respectively, as shown in Table 2. Evaluations from 1 to 5 were made. In Comparative Examples 1 and 2, since the cleaning member chattered and a significant image defect due to poor cleaning occurred when the paper was passed at 12.5 ° C./10% RH, the subsequent paper passing durability was stopped. The evaluation results are shown in Table 2.

  From the above evaluation results, the effect of the present invention was confirmed.

From the results of Examples 1 to 3 and Comparative Examples 4 to 5, it was confirmed that the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer of the photoreceptor was 6.60 × 10 ²² atoms / cm ³ or more. It can be seen that it is effective for abrasion and image flow.

Further, based on the results of Examples 1 and 10 , Reference Examples 1 to 5 , and Comparative Examples 1 to 3, an inorganic fine powder having a Mohs hardness of 4.0 or more and 7.0 or less when toner is used. It has been found that the cleaning performance can be maintained well without causing squealing or chattering even under the condition of strongly pressing the cleaning member. When the Mohs hardness of the inorganic fine powder was less than 4.0, the squeal at the stop of the photoconductor or the chatter at the start-up occurred, and accordingly, the toner slipped through the cleaning blade, causing image defects and contaminating the charging roller. When the Mohs hardness exceeded 7.0, the photoconductor was scraped, and at the end of the endurance, although slight, streak-like image defects due to circumferential scratches on the photoconductor were observed.

From the results of Reference Examples 1 to 5 , when the number average particle size of the primary particles of the inorganic fine powder is 30 nm or more and 800 nm or less, the squealing, chattering, cleaning property and image flow of the photoreceptor are good, and 100 nm or more and 300 nm or less. The result was even better. If the thickness is less than 30 nm or more than 800 nm, the lubricating effect at the nip where the cleaning blade and the photosensitive member are in contact with each other is reduced, and the photosensitive member is liable to squeal and chatter. When it exceeded 800 nm, it was contaminated black due to toner passing through.

From the results of Examples 1 and 10 and Reference Examples 1 to 3 , it was found that the inorganic fine powder was preferably strontium titanate, and in comparison with Examples 1 and 10, it was further preferable that the inorganic fine powder had a hexahedral shape. Strontium titanate has a slightly positive charging characteristic and has a shape with ridges and vertices, which has some effect and is optimally placed in the nip part of the cleaning blade and the photoconductor and works well. I think.

  From the results of Examples 1 to 9 and Comparative Examples 4 to 5, the ratio of the atomic density of carbon atoms to the sum of the atomic densities of silicon atoms and carbon atoms in the surface layer of the electrophotographic photosensitive member is 0.61 or more and 0.75. It was found that the following is more preferable. If this ratio is less than 0.61, the gradation is deteriorated, and if it exceeds 0.75, the sensitivity is lowered.

  Furthermore, from the results of Examples 1 to 9 and Comparative Examples 4 to 5, the ratio of the atomic density of hydrogen atoms to the sum of the atomic density of silicon atoms, the atomic density of carbon atoms, and the atomic density of hydrogen atoms is 0.30 or more and 0 It was found that it was more preferable that it be .45 or less. When this ratio is less than 0.30, the sensitivity is deteriorated, and when it exceeds 0.45, the wear resistance is deteriorated.

  In the evaluation (2) of squeal and chatter, in Comparative Examples 3 to 5, blade turning occurred during continuous sheet passing at 23 ° C./50% RH, and the sheet passing durability was stopped. Comparative Example 3 is an inorganic fine powder having a high Mohs hardness, and Comparative Examples 4 to 5 are photoreceptors having a low atomic density. In both cases, it is considered that the polishing force on the surface of the photoconductor by the inorganic fine powder is large. Therefore, the surface of the photoconductor is scraped by the inorganic fine powder, and the inorganic fine powder slips through the minute groove and disappears. It seems to have been turned up.

Thus, the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer of the electrophotographic photosensitive member is set to 6.60 × 10 ²² atoms / cm ³ or more, and the inorganic fine powder contained in the toner has a Mohs hardness of 4 When the value is 0.0 or more and 7.0 or less, the cleaning member does not squeal or chatter, and image defects such as image flow can be suppressed without accelerating the wear of the photosensitive member. A long-life and low-power image forming apparatus can be obtained.

  Furthermore, the number average particle size of the inorganic fine powder primary particles is 30 nm to 800 nm, the main component is strontium titanate, and the shape is a hexahedron that is a convex polyhedron surrounded by six squares, The ratio of the atomic density of carbon atoms to the sum of the atomic densities of silicon atoms and carbon atoms in the surface layer of the electrophotographic photosensitive member is 0.61 or more and 0.75 or less, and the atomic density of silicon atoms and the atomic density of carbon atoms If the ratio of the atomic density of the hydrogen atom to the sum of the atomic densities of the hydrogen atoms is not less than 0.30 and not more than 0.45, the gradation and density of the output image are further excellent, which is severe for the noise and chatter of the photoreceptor. An image forming apparatus that can maintain good image quality even when used for a long time under various conditions can be obtained.

It is a schematic diagram of an example of the plasma CVD apparatus used for preparation of the electrophotographic photosensitive member of the present invention. It is a typical schematic sectional drawing of the electrophotographic apparatus using the conventional corona charging system. It is a schematic sectional drawing of the electrophotographic apparatus remodeled to the contact charging system used in the Example.

Explanation of symbols

1100 Deposition apparatus 1110 Reaction vessel 1111 Cathode electrode 1112 Conductive substrate 1113 Heater for substrate heating 1114 Gas introduction tube 1115 High-frequency matching box 1116 Gas piping 1117 Leak valve 1118 Main valve 1119 Vacuum gauge 1120 High-frequency power source 1121 Insulating material 1123 Receiving base 1200 Gas supply Devices 1211 to 1215 Mass flow controllers 1221 to 1225 Cylinders 1231 to 1235 Valves 1241 to 1245 Inflow valves 1251 to 1255 Outflow valves 1260 Auxiliary valves 1261 to 1265 Pressure regulators

Claims (5)

A step of charging the electrostatic image carrier with a charging member; an electrostatic latent image forming step for forming an electrostatic latent image on the charged electrostatic image carrier; and a toner carried on the toner carrier. A developing process for transferring to an electrostatic latent image for visualization, a transfer process for transferring a toner image formed on the electrostatic charge image carrier onto a recording medium, and a surface of the electrostatic charge image carrier after the transfer process as a cleaning member And an image forming method having a cleaning step of cleaning with
The electrostatic image bearing member is an electrophotographic photosensitive member in which at least a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide are sequentially stacked, and the atomic density of silicon atoms and carbon atoms in the surface layer The sum of the atomic densities of 6.60 × 10 ²² atoms / cm ³ or more,
The toner is a toner having toner particles containing at least a binder resin and a colorant and an inorganic fine powder, the inorganic fine powder is strontium titanate, and the inorganic fine powder has a Mohs hardness of 4.0 or more and 7 An image forming method, wherein the image forming method is 0.0 or less.   2. The ratio of the number of carbon atoms to the sum of the number of silicon atoms and the number of carbon atoms in the surface layer of the electrophotographic photosensitive member is 0.61 or more and 0.75 or less. The image forming method described in 1.   The ratio of the number of hydrogen atoms to the sum of the number of silicon atoms, the number of carbon atoms, and the number of hydrogen atoms in the surface layer of the electrophotographic photosensitive member is 0.30 or more and 0.45 or less. The image forming method according to claim 1 or 2.   The image forming method according to any one of claims 1 to 3, wherein the inorganic fine powder has a number average particle size of primary particles of 30 nm or more and 800 nm or less.   5. The inorganic fine powder according to any one of claims 1 to 4, wherein the inorganic fine powder contains 50% by number or more of particles having a hexahedral particle shape that is a convex polyhedron surrounded by six quadrangles. The image forming method described.

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