JP5483994B2 - Image forming method - Google Patents

Description

  The present invention relates to a toner used in an image forming method for visualizing an electrostatic charge image in electrophotography and an image forming method.

  Conventionally, as an image forming method in electrophotography, a photoreceptor is used as an electrostatic charge image carrier, and the surface of the photoreceptor is uniformly charged by a charging method such as corona charging using a primary charger. Thereafter, the image is exposed to form an electrostatic image on the surface of the photoconductor, and the electrostatic image is developed by a developing method such as a jumping development method or a magnetic brush method to form a toner image on the surface of the photoconductor. After this, if necessary, pre-transfer processing is performed using a pre-transfer charger (usually combining with application of corona by DC or AC, or light neutralization), and a toner image is transferred onto the transfer material. Transfer by. Thereafter, the toner image is sent to a fixing device to fix the image. On the other hand, a method is known as a general method in which the toner remaining on the photosensitive member after transfer is removed by a cleaning device to prepare for the next image formation.

  In recent years, as image forming methods such as copiers and printers have become widespread, the performance required for image forming methods and toners has become higher, and further higher image quality, higher speed, smaller size, and higher durability. Stability and high reliability are required.

  In order to achieve higher image quality, it is necessary to control the charging characteristics and flow characteristics of the toner to appropriate values. For this purpose, a method of mixing toner particles and inorganic fine powder is generally used. .

  As the inorganic fine powder, silicon dioxide, titanium dioxide, aluminum oxide and the like are known, and various methods for subjecting these inorganic fine powders to a hydrophobization treatment have been proposed for the purpose of improving charging characteristics and flow characteristics. ing. For example, in silica fine particles, there are known methods of reacting silane coupling treatment agents such as dimethyldichlorosilane and hexamethyldisilazane with silanol groups on the surface of silica fine particles, and methods of hydrophobizing by treating the surface with silicone oil. ing.

  Of these, silica fine particles treated with silicone oil are preferably used because they have sufficient hydrophobicity and charge characteristics, flow characteristics, and transfer properties are improved. For example, Patent Document 1 proposes silica fine particles having excellent transferability by setting the release rate of silicone oil to 10 to 70%. Further, Patent Document 2 proposes silica fine particles having improved dispersibility by performing a two-step treatment for coupling with an alkylsilazane compound after the silicone oil treatment.

  However, in any toner using silica fine particles, the corona charger wire may be contaminated by scattering of the silica fine particles from the toner into the copying machine due to the liberation of the silica fine particles, resulting in a problem of deteriorating image quality such as vertical stripes. It was.

  The cause of the wire contamination is that the silica fine particles that have been subjected to the hydrophobization treatment tend to form aggregates during the hydrophobization treatment. Since the aggregate has a small specific surface area and weak interaction with the toner, the aggregate is easily separated from the toner particles, and the aggregate of silica fine particles is easily scattered from the developing unit alone.

  Since the scattered silica particles have a small specific gravity, it is considered that the silica fine particles fly in the copying machine according to the air flow in the copying machine, reach the discharge wire of the corona charger, and cause wire contamination of the charger.

  With respect to this problem, Patent Document 3 proposes a toner that is difficult to form an aggregate of silica fine particles if the specific surface area and bulk density of the silica fine powder are within the specified ranges, and is effective in wire contamination. Yes.

  On the other hand, as a photoconductor, a hydrogenated amorphous silicon carbide (hereinafter referred to as “a-SiC”) photoconductor is preferably used in a high-speed copying machine that requires high durability stability and high reliability. The a-SiC photoreceptor has advantages in that it has high sensitivity over the entire visible light region, has high surface hardness, and is excellent in durability and heat resistance. Therefore, since there is almost no deterioration due to repeated use, it is expected as a photoreceptor capable of forming a clear electrostatic charge image over a long period of time.

  However, it is known that the a-SiC photoconductor has many dangling bonds, and the dangling bonds supplement the optical carriers to inhibit the formation of a clear electrostatic charge image.

  On the other hand, Patent Document 4 proposes a method for obtaining a photoconductor with less dangling bonds by forming a photoconductor layer by a method in which the plasma density is defined in the method of forming a photoconductor by plasma CVD. doing.

JP 2002-174926 A JP 2004-168559 A Japanese Patent Laid-Open No. 05-0666608 Japanese Patent Application Laid-Open No. 08-211641

  However, in the above-described conventional example, it is possible to suppress the release of silica fine particles, but it is not possible to eliminate them completely, and there are silica fine particles that are released even though they are minute. Further, as the speed increases, the share and centrifugal force received by the toner and silica fine particles become stronger, and the scattering of the silica fine particles has become severe.

  Further, as the share and centrifugal force received by the toner become stronger, the situation of toner scattering has become severe. When toner with fine silica particles adhering thereto is scattered on the charger wire, the charger wire may be contaminated.

  That is, even with the conventional method, since the further increase in the speed has been achieved, wire contamination is promoted by the scattering of silica particles and toner and the increase of the corona discharge current of the charger, so there is a problem in image quality and durability. There was a case.

  On the other hand, the a-SiC photoconductor excellent in durability stability is excellent as a photoconductor for a high-speed electrophotographic apparatus, but in order to maintain a predetermined dark portion surface potential, it is in comparison with other photoconductors. In some cases, a large capacity corona discharge current is required.

  Further, as the speed increases, the time for the a-SiC photoconductor to pass through the charged region is also shortened, so that the corona discharge current for maintaining a predetermined dark portion potential may be further increased.

  When the a-SiC photoreceptor has dangling bonds, the surface becomes structurally weak and is easily oxidized by corona discharge. As a result, the surface conductivity changes and causes image defects such as image flow.

  On the other hand, in the above prior art, a method for obtaining a photoconductor with less dangling bonds has been proposed. However, when the corona discharge current is increased, the oxidation of the surface of the photoreceptor is further promoted, and even in the above prior art, it may not be sufficient in terms of high durability and high image quality.

  Further, when the silica fine particles subjected to the silicone oil treatment adhere to the surface of the photosensitive member with a low immobilization rate, the silicone oil remains on the surface of the photosensitive member although being minute. When this silicone oil volatilizes in the copying machine, a thin film is formed on the wire of the charger in a state where the corona discharge current is high, which may be contaminated.

  Further, the silicone oil adhering to the surface of the photoconductor acts as a lubricating oil between the photoconductor and the cleaning blade when cleaning the toner remaining on the photoconductor, and has a high surface hardness. In some cases, the SiC photoconductor also promotes the abrasion of the photoconductor.

  Recent electrophotographic apparatuses are required to have higher speed, higher image quality, and higher durability. In particular, when aiming for high durability, it is necessary to replace as few parts as possible. However, it has been difficult to achieve both high speed and high durability stability with only conventional methods.

  An object of the present invention is to provide a toner and an image forming method that solve the above problems. That is, it is an electrophotographic apparatus aiming at further speeding up, and to provide a toner and an image forming method in which wire contamination does not become a problem even when used for a long time. It is another object of the present invention to provide a toner and an image forming method that suppresses the photoconductor scraping and the oxidation reaction on the surface of the photoconductor and has high speed, high image quality, and high durability stability.

In order to solve the above problems, the present invention charges an electrostatic charge image carrier for carrying an electrostatic charge image, forms an electrostatic charge image on the charged electrostatic charge image carrier, developed to form a toner image on the electrostatic charge image bearing member, an image forming how having a step of transferring to a transfer material the toner image on the electrostatic charge image bearing member,
The electrostatic charge image carrier is a photoreceptor in which at least a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide are sequentially laminated, and the atomic density of carbon atoms and carbon atoms in the surface layer of the photoreceptor The sum of the atomic densities of 6.60 × 10 ²² atoms / cm ³ or more,
The toner is toner having toner particles containing at least a binder resin and a colorant, and silica fine particles, the silica fine particles are at least treated with a silicone oil, and the carbon amount standard of the silicone oil is used. images formed how to, wherein the immobilization of not more than 30 mass% to 95 mass% relates.

  According to the present invention, it is possible to provide a toner and an image forming method in which the wire contamination of the charger due to toner, silica fine particles, and silicone oil does not become a problem even in an electrophotographic apparatus aiming at further speeding up. Further, it is possible to provide a toner and an image forming method that suppress the oxidation and abrasion of the surface of the photoreceptor and have high durability stability.

It is a schematic diagram of an example of the plasma CVD apparatus used for preparation of the photoconductor of this invention. It is a methanol dripping permeation curve. FIG. 3 is a schematic diagram of a developing device having a plurality of toner carriers.

  In the electrophotographic apparatus that has been increased in speed, the present inventors have developed silica fine particles and hydrogenated amorphous silicon carbide in order to suppress wire contamination of the charger and oxidation and scraping of the surface of the positively charged image carrier (photoconductor). The investigation was conducted focusing on the (a-SiC) photoreceptor.

  As a result, as the silica fine particles, the fixing rate of the silicone oil is controlled, and in the a-SiC photoconductor, the photoconductor having a surface layer having a certain atomic density or more is used to solve the above-mentioned problem. It came to.

  In the present invention, the reason why the above-described effect can be obtained is not necessarily clear, but the silica particle or silicone flying to the charger effectively works as an interaction between the photoconductor, the silica fine particle and the silicone oil. This is considered to be because the volatilization of oil can be suppressed.

That is, the present invention is characterized in that the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer of the photoreceptor is 6.60 × 10 ²² atoms / cm ³ or more, preferably 6.81 × 10 6. It is good that it is ²² atoms / cm ³ or more.

When the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer of the a-SiC photoreceptor has a high density of 6.60 × 10 ²² atoms / cm ³ or more, the unit is in contact with silica fine particles and silicone oil The number of atoms per area increases. The atoms constituting the silica fine particles and the silicone oil and the atoms (Si and C) constituting the surface layer of the a-SiC photoreceptor are essentially the same atoms, and it is considered that attractive force acts between the two. It is done. An increase in the number of atoms per unit area means that a strong interaction works, and it is considered that the release of silica fine particles remaining on the surface of the a-SiC photoreceptor and the volatilization of silicone oil are suppressed.

When the sum of the atomic densities of silicon atoms and carbon atoms constituting the surface layer of the a-SiC photoconductor is 6.60 × 10 ²² atoms / cm ³ or less, oxidation and desorption of carbon atoms on the photoconductor surface are performed by the charging step. Is generated, and the bond with the silicon atom is easily broken. It is considered that the oxidation reaction of the surface layer of a-SiC occurs due to the reaction of the oxidized substance with the resulting dangling bond, and the density of silicon atoms and carbon atoms becomes coarse. As a result, the number of atoms in contact with the silica fine particles treated with the silicone oil per unit area is reduced, and the interaction between the photoconductor and the silica fine particles becomes difficult to work, and wire contamination is considered to occur. Therefore, the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer of the a-SiC photoreceptor needs to be 6.60 × 10 ²² atoms / cm ³ or more.

  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 constituting the surface layer of the photoreceptor (hereinafter referred to as “H atom ratio”). Is 0.30 or more and 0.45 or less, it becomes possible to suppress wire contamination more effectively.

  In the a-SiC surface layer having a high atomic density, when the H atomic ratio is less than 0.30, the optical band gap is narrowed, and the sensitivity of the photoreceptor may be deteriorated. As a result, in order to obtain a desired potential, a higher corona discharge current may be required, and it is considered that the contamination of the wire is accelerated. Thereby, it is preferable to make H atomic ratio larger than 0.30.

  Further, when the H atom ratio is larger than 0.45, a termination group having a large number of hydrogen atoms such as a methyl group tends to increase in the a-SiC surface layer. That is, distortion is generated in the bonds between atoms existing around. As a result, the interaction with the silica fine particles is weakened, and wire contamination may occur. For these reasons, the H atomic ratio is preferably 0.45 or less.

  Next, an example of a method for producing a photoreceptor according to the present invention will be described. FIG. 1 schematically shows an example of an apparatus for depositing a photoconductor by an RF plasma CVD method using a high-frequency power source for producing the 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 on 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 moved to, for example, 50 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, and a deposited film is formed.

  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 layers 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. As described above, when an a-SiC surface layer having a high atomic density according to the present invention is manufactured, the balance between the amount of gas and high-frequency power is generally important, although it depends on the conditions at the time of surface layer preparation. is there. That is, it is better that the amount of gas supplied to the reaction vessel is smaller, the high frequency power is better, the pressure in the reaction vessel is higher, and the temperature of the conductive substrate is higher.

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 raw material 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 raw material gas. This is because the networking of silicon and carbon atoms has been promoted.

  Furthermore, by raising the temperature of the conductive substrate, the surface movement distance of the active species that has reached the conductive substrate is increased, and a more stable bond can be created. As a result, it is considered that each atom is bonded to a more structurally stable arrangement as the a-SiC surface layer.

  The measuring method of Si + C atom density, C atom ratio, and H atom ratio is shown below.

  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 in a 15 mm square 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 volume ratio of the surface layer to the air layer of 8: 2 is used as a calculation model on the outermost surface. Software: J.M. A. Woollam Co. , Inc. The relationship between the wavelength, Ψ, and Δ at each incident angle was obtained by calculation using WVASE32 manufactured by WVASE32. Furthermore, the film thickness of the surface layer when the mean square error of the relationship between the wavelength obtained by this calculation and Ψ and Δ and the relationship between the wavelength obtained by measuring the measurement sample and Ψ and Δ 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 sample for measurement is measured in the surface layer in the RBS measurement area by RBS (Rutherford backscattering method) (manufactured by Nissin High Voltage Co., Ltd .: Backscattering measurement device AN-2500). The number of silicon atoms and carbon atoms was measured, and C / (Si + C) was determined. Next, with respect to the number of silicon atoms and carbon atoms determined from the RBS measurement area, the atomic density of silicon atoms, the atomic density of carbon atoms, and the Si + C atoms are determined using the surface layer thickness determined by spectroscopic ellipsometry. The density was determined.

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

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.

  As described above, a photoconductor has been described that suppresses the release of silica fine particles and suppresses wire contamination even when subjected to a strong centrifugal force. However, it is difficult to completely suppress wire contamination only by increasing the atomic density of silicon atoms and carbon atoms in the surface layer of the photoreceptor, and silica fine particles that interact effectively with the photoreceptor are essential. .

  That is, the silica fine particles are at least treated with silicone oil, and the carbon oil-based immobilization rate of the silicone oil is 30% by mass to 95% by mass, preferably 60% by mass to 90% by mass. It is characterized by being.

  When the immobilization rate of the silicone oil is less than 30% by mass, it is considered that the silicone oil adhering to the surface of the silica fine particles has a weak adhesive force with the silica fine particles. Therefore, even if the silicone oil on the surface of the photoconductor and the surface of the silica fine particles interacts, the silica fine particles may be liberated. Furthermore, excessive silicone oil remains on the photoconductor, which increases the volatile components of the silicone oil and causes wire contamination. Furthermore, excessively remaining silicone oil on the photoreceptor tends to increase the abrasion of the photoreceptor during cleaning, which may affect durability stability.

  Moreover, as a method for making the immobilization rate of the silicone oil greater than 95% by mass, it is necessary to relatively reduce the addition amount of the silicone oil. That is, the immobilization rate of the silicone oil is increased, but the surface of the silica fine particles may not be uniformly treated. As a result, minute unevenness occurs in the treatment state on the surface of the silica fine particles, so that the interaction between the surface of the photoreceptor and the surface of the silica fine particles becomes weak, and wire contamination occurs.

  The method for measuring the immobilization rate of silicone oil will be described below.

(Extraction of free silicone oil)
1. Place 0.5 g of silica fine particles and 40 ml of chloroform in a beaker and stir for 2 hours.
2. Stop stirring and let stand for 12 hours.
3. The sample is filtered and washed 3 times with 40 ml of chloroform.

(Measurement of carbon content)
The sample is burned at 1100 ° C. under an oxygen stream, the amount of generated CO and CO ₂ is measured by IR absorbance, and the amount of carbon in the sample is measured. The carbon amount before and after extraction of the silicone oil is compared to calculate the immobilization rate based on the carbon amount of the silicone oil.
1. 2 g of sample is put into a cylindrical mold and pressed.
2. 0.15 g of the pressed sample is precisely weighed, placed on a combustion board, and measured with HORIBA, Ltd. EMA-11.
3.100- (carbon amount before extraction-carbon amount after extraction) / carbon amount before extraction × 100
Is the immobilization rate based on the carbon content of silicone oil.

  The raw material of the silica fine particles used to obtain the silica fine particles of the present invention is produced from a dry process produced by vapor phase oxidation of a silicon halogen compound or dry silica called fumed silica, and water glass. Both wet silicas to be used are mentioned. In the present invention, dry silica having less silanol groups on the surface and inside and no production residue is preferred.

  The silica fine particles used in the present invention need to be subjected to a water-repellent treatment in terms of hardness. Examples of the water-repelling treatment include a method of treating with an organosilicon compound that is chemically or physically adsorbed with a silica base material. In order to obtain the effects of the present invention, at least treatment with silicone oil is required.

The silica fine particles of the present invention preferably have a BET specific surface area of the silica raw material before treatment of 50 m ² / g or more and 400 m ² / g or less for uniform silicone oil treatment.

  The method for treating the silicone oil necessary for obtaining the silica fine particles of the present invention may be obtained by directly mixing the silica fine particles and the silicone oil using a mixer such as a Henschel mixer. A method of spraying silicone oil may be used. Alternatively, it may be prepared by dissolving or dispersing silicone oil in a suitable solvent and then mixing with the silica fine particles and removing the solvent.

As the silicone oil, dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil and the like can be used. Among them, dimethyl silicone oil is preferable, and the viscosity of the silicone oil is preferably 300 mm ² / s or less at 25 ° C.

  The silica fine particles used in the present invention are treated with 5 to 30.0 parts by mass, preferably 10.0 to 28.0 parts by mass of silicone oil with respect to 100 parts by mass of the silica raw material. It is preferable.

  When the silicone oil is scientifically bonded to the surface of the silica base, the immobilization rate based on the carbon amount of the silicone oil increases. Therefore, as the amount of silicone oil added increases, the amount that cannot be chemically bonded to the surface of the silica bulk increases, so when the amount of silicone oil treated exceeds 30.0 parts by mass, the amount of free silicone oil increases and charging Contamination of the wire is easy to occur.

  If the treatment amount of the silicone oil is less than 5.0 parts by mass, the treatment state on the surface of the silica fine particles will be uneven, and the effect of the present invention will be difficult to obtain.

  A known technique is used for the surface treatment method of the silica base with silicone oil. In this treatment, in order to achieve the optimum immobilization ratio of the silicone oil to the silica base, the silica base is treated with heating. Is preferred.

  The treatment temperature is preferably in the range of 150 ° C. or higher and 350 ° C. or lower, more preferably 150 ° C. or higher and 250 ° C. or lower.

  By setting to this treatment temperature range, the oil treatment can be performed uniformly without unevenness, and the immobilization rate of the silicone oil to the surface of the silica base material can be easily increased.

  In the present invention, an excellent effect is obtained when the content of the silica fine particles having the silicone oil immobilization ratio is 0.01 parts by mass or more and 3.00 parts by mass or less with respect to 100 parts by mass of the toner particles. When the amount exceeds 3.00 parts by mass, the ratio of the silica fine particles on the surface of the toner particles becomes too large, and the silica fine particles themselves are easily liberated, which may promote the wire contamination of the charger.

  Further, the silica fine particles are more preferably hydrophobic silica fine particles that are surface-treated with silicone oil and then surface-treated with a silane compound and / or a silazane compound. By further supplementing the surface of the silica fine particles that cannot be reacted only with the silicone oil treatment with a silane compound and / or a silazane compound, the density of the treatment agent bonded to the surface of the silica fine particles is increased. As a result, the interaction with the surface of the photosensitive member is more effectively expressed, and the wire contamination of the charger may be further suppressed.

  Examples of the silane compound used in the present invention include alkoxysilanes such as methoxysilane, ethoxysilane, and propoxysilane, halosilanes such as chlorosilane, bromosilane, and iodosilane, hydrosilanes, alkylsilanes, arylsilanes, vinylsilanes, and acrylics. Examples thereof include silanes, epoxy silanes, silyl compounds, siloxanes, silylureas, silylacetamides, and silane compounds having different substituents of these silane compounds at the same time. By using these silane compounds, fluidity, transferability and charge stabilization can be obtained. A plurality of these silane compounds may be used.

  Specific examples include trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyl. Trichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldi Siloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane And dimethylpolysiloxane containing 2 to 12 siloxane units per molecule and containing a hydroxyl group bonded to one Si at each terminal unit. You may use these as a 1 type, or 2 or more types of mixture.

  The silazane compound used in the present invention is a general term for compounds having a Si—N bond in the molecule. Specifically, dimethyldisilazane, trimethyldisilazane, tetramethyldisilazane, pentamethyldisilazane, hexamethyldisilazane, octamethyltrisilazane, hexamethylcyclotrisilazane, tetraethyltetramethylcyclotetrasilazane, tetraphenyldimethyldi Examples include silazane, dipropyltetramethyldisilazane, dibutyltetramethyldisilazane, dihexyltetramethyldisilazane, dioctyltetramethyldisilazane, diphenyltetramethyldisilazane, octamethylcyclotetrasilazane, and the like. Moreover, you may use the organic fluorine-containing silazane compound etc. which substituted these silazane compounds partially with the fluorine etc. Particularly in the present invention, hexamethyldisilazane is preferably used.

  A well-known technique is used for the method of processing with a silane compound and / or a silazane compound. For example, silica particles treated with silicone oil are put into a treatment tank, and a predetermined amount of silane compound and / or silazane compound is dropped or sprayed while stirring inside the treatment tank with a stirring member such as a stirring blade. To mix. At this time, the silane compound and / or silazane compound can be diluted with a solvent such as alcohol. The silica fine particles containing the mixed and dispersed treatment agent are heated to a treatment temperature of 150 ° C. or higher and 350 ° C. or lower (preferably 150 ° C. or higher and 250 ° C. or lower) in a nitrogen atmosphere and refluxed for 0.5 to 5 hours with stirring.

  As a preferred production method, silica fine particles treated with silicone oil are put into a treatment tank, and the treatment tank is held at a temperature not lower than the boiling point of the silane compound and / or silazane compound to be treated and not higher than the decomposition temperature. Water vapor is blown here so that the hydroxyl groups on the surface of the silica fine particles are easily reacted with the silane compound or silazane compound. Further, it is preferable to add a silane compound and / or a silazane compound and treat the surface of the silica fine particles by a gas phase reaction. Thereafter, it is also possible to remove surplus materials such as surplus treatment agents as necessary.

  In addition, it is preferable to perform the crushing treatment before treating the silane compound and / or the silazane compound, in order to perform a uniform treatment.

  The preferable processing amount of these alkoxysilanes or silazanes is 2.0 to 30.0 parts by mass with respect to 100 parts by mass of the silica base.

Further, when the methanol wettability of the silica fine particles is D90 (volume%) when the transmittance is 90% and the methanol concentration when the transmittance is 70% is D70 (volume%), the following formula ( It is more preferable to satisfy the relationship 1).
D70−D90 ≦ 5.0 (1)

  That is, the difference when the methanol concentration when the transmittance of light having a wavelength of 780 nm is 90% is D90 (volume%) and the methanol concentration when the transmittance is 70% is D70 (volume%) is 5.0. It is characterized by being not more than volume%.

  The smaller the value of D70-D90, the more uniform the silicone oil is on the surface of the silica fine particles. When the value of D70-D90 is larger than 5.0, the non-uniformity of the presence of silicone oil causes unevenness in the interaction with the surface of the photoreceptor, and free silica fine particles are likely to be generated, resulting in wire contamination. May occur.

  The measurement method of methanol wettability is shown below.

  The methanol wettability of the silica fine particles is measured using a methanol dropping transmittance curve. Specifically, as the measuring device, for example, a powder wettability tester WET-100P (manufactured by Reska Co.) is used, and a methanol dropping transmittance curve measured under the following conditions and procedures is used.

  First, in order to remove bubbles and the like in a measurement sample, 70 ml of a hydrated methanol solution composed of 60% by volume of methanol and 40% by volume of water is placed in a cylindrical glass container having a diameter of 5 cm and a thickness of 1.75 mm. Disperse for 5 minutes with an ultrasonic disperser.

Into this, 0.1 g of fine silica particles as a specimen is precisely weighed and added to prepare a sample solution for measuring the hydrophobic properties of the fine silica particles. Then, the measurement sample liquid is set in a powder wettability tester WET-100P (manufactured by Reska). The sample liquid for measurement is stirred at a speed of 6.7 s ⁻¹ (400 rpm) using a magnetic stirrer. As the rotor of the magnetic stirrer, a spindle type rotor having a length of 25 mm and a maximum barrel diameter of 8 mm coated with a fluororesin is used.

  Next, the transmittance was measured with light having a wavelength of 780 nm while continuously adding methanol to the measurement sample solution at a dropping rate of 1.3 ml / min through the above-described apparatus, as shown in FIG. Create a methanol drop transmission curve.

The BET specific surface area of the silica fine particles used in the present invention is preferably 100 m ² / g or more and 400 m ² / g or less. When the BET specific surface area of the silica fine particles is larger than 400 m ² / g, the adhesion force between the silica fine particles becomes too large and tends to aggregate, so that it is difficult to uniformly disperse the toner particle surfaces. On the other hand, when the BET specific surface area of the silica fine particles is smaller than 100 m ² / g, the fluidity of the toner may be lowered.

  In addition, it is preferable to design the degree of liberation of the external additive from the toner particles as follows in order to obtain the effects of the present invention.

  The external additive particles containing silica fine particles present on the toner particle surface tend to be easily released by receiving a mechanical share such as stirring in the developing device.

  However, in order to maximize the effect of the present invention, it is preferable to release the external additive from the toner particles as little as possible.

  For that purpose, the external addition process at the time of toner production becomes very important. In other words, it is necessary to make the external additive particles containing silica fine particles as uniform as possible to the toner particles and to adhere with the optimum physical adsorption force.

  For example, in a conventional mixer such as a Henschel mixer, it is possible to obtain a uniform and optimum adhesive force by mixing and mixing multiple times, such as external addition at low speed and then external addition at high speed. Therefore, it is preferable.

  The degree of liberation of the external additive of the toner thus prepared is measured by the following method.

(Measurement of external additive liberation)
[Adjust sample]
1. A 200 ml beaker made of glass was charged with 50 ml of an aqueous electrolytic solution. As a dispersant, 10 mass of neutral detergent for cleaning a precision measuring instrument having a pH of 7 consisting of non-ionic surfactant, anionic surfactant and organic builder. About 0.3 ml of a diluted solution obtained by diluting a 3% aqueous solution (made by Wako Pure Chemical Industries, Ltd.) with ion-exchanged water about 3 times by mass is added.
2. 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 Nikkei Bios) with 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.
3. 1 above. 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.
4). 3 above. In the state where the electrolytic aqueous solution in the beaker is irradiated with ultrasonic waves, 0.2 g of toner particles are added to the electrolytic aqueous solution 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.
5. After 60 seconds, the beaker is taken out and immediately left on a magnet (for example, neodymium magnet 30φ × 15 mm manufactured by ASONE). After 30 seconds, 10 ml is collected from the supernatant with a micropipettor.

[Measurement of liberty of external additives]
The degree of liberation of external additives can be measured using, for example, a Shimadzu spectrophotometer UV3100PC (manufactured by Shimadzu Corporation) and a quartz cell having an optical path length of 1 cm.

  The obtained supernatant solution is put in a quartz cell having an optical path length of 1 cm and quickly set in an apparatus, and the transmittance T of the supernatant solution at a wavelength of 500 nm of incident light is measured. At this time, an electrolytic aqueous solution in which toner is not dissolved is put in the control cell.

  The transmittance T is defined as the degree of liberation of the external additive. The larger the value, the smaller the amount of free components and the less the external additive is released from the toner particles.

  The transmittance by UV measurement is 55.0% or more, preferably 70.0% or more, more preferably 80.0% by mass or more.

  A transmittance of 55.0% or more indicates that the external additive adheres to the toner particles with an optimum strength, and the effects of the present invention can be more easily obtained.

  On the other hand, the degree of liberation of the external additive being less than 55.0% by mass indicates that the external additive is easily liberated from the toner particles due to a mechanical share such as stirring in the developing device. In particular, when the treatment of the silica fine particles is uneven or when the silicone oil is too liberated, the physical adhesion is weakened and the silica fine particles themselves are likely to be liberated. As a result, the wire contamination of the charger may be promoted as a free external additive.

  Further, the toner carrier includes a first toner carrier and a second toner carrier, and the first toner carrier on the upstream side in the rotation direction of the electrostatic charge image carrier is the second toner carrier on the downstream side. More preferably, the amount of toner on the body is regulated to a predetermined amount using an image forming method.

  In the above configuration, it is possible to form a toner image on the photosensitive member with the first toner carrier and to treat the toner image with the second toner carrier. That is, in the toner image formed by the first toner carrier, the silica fine particles having a weak adhesive force are pulled back by the second toner carrier and are considered not to fly in the copying machine. As a result, it has the effect of suppressing wire contamination.

  The most important feature of the present invention is that, in the electrophotographic apparatus aiming at further speedup by combining the photoconductor and the toner, the wire of the charger using the toner and the silica microparticles. It has been found that contamination is not a problem. Furthermore, it is possible to provide a toner and an image forming method having high durability stability by suppressing oxidation and scraping on the surface of the photoreceptor, and the present invention has been completed.

  Examples of the binder resin used in the toner of the present invention include the following. Vinyl resin, styrene resin, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, Silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin. Among these, styrene copolymer resins, polyester resins, hybrid resins in which a polyester resin and a vinyl resin are mixed, or partially reacted are used as resins that are preferably used.

  In the present invention, a polyester resin that is less prone to over-pulverization is preferable from the viewpoint of controlling the adhesion of silica fine particles to toner particles.

  The components of the polyester resin used in the present invention are as follows.

  The following are mentioned as a bivalent alcohol component. Ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated bisphenol A, bisphenol represented by formula (1) and derivatives thereof:

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ、ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０乃至１０である。）

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)

  And diols represented by formula (2).

  Among these, bisphenol and its derivatives are preferable in controlling charging of toner particles and maintaining the glass transition temperature.

  Examples of the divalent acid component include the following dicarboxylic acids or derivatives thereof. Benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride or their anhydrides or lower alkyl esters thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or their anhydrides or lower thereof Alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or anhydrides thereof or lower alkyl esters thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid Or its anhydride or its lower alkyl ester. In particular, terephthalic acid and isophthalic acid are preferable.

  In the present invention, a release agent (wax) can be used as necessary in order to impart releasability to the toner. As the wax, hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax are preferably used because of easy dispersion in toner particles and high releasability. If necessary, a small amount of one or two or more kinds of waxes may be used in combination. Examples include the following:

  Oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax, sazol wax, and montanate ester wax; deacidified carnauba Deoxidized part or all of fatty acid esters such as wax. Furthermore, the following are mentioned. 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, carnauvyl alcohol, seryl alcohol, Saturated alcohols such as sil alcohols; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylene bis stearic acid amide, ethylene biscapric acid amide Saturated fatty acid bisamides such as ethylene bislauric acid amide and hexamethylene bis stearic acid amide; ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipine Amides, unsaturated fatty acid amides such as N, N-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, aromatic bisamides such as N, N-distearylisophthalic acid amide; calcium stearate, calcium laurate, Fatty acid metal salts such as zinc stearate and magnesium stearate (generally called metal soap); waxes grafted with aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; behenine A partially esterified product of a fatty acid such as an acid monoglyceride and a polyhydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of a vegetable oil.

  Specific examples that can be used include the following. Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industry Co., Ltd.); High Wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals) Sazol H1, H2, C80, C105, C77 (Sazol Wax); HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP-12 (Nippon Seiwa Co., Ltd.) ), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark) 350, 425, 550, 700 (Toyo Petrolite); wood wax, beeswax, rice wax, candelilla wax, carnauba wax ( Celerica NODA).

  The timing of adding the release agent (wax) may be added at the time of melt kneading during the production of the toner, or may be at the time of producing the binder resin, and is appropriately selected from existing methods. These release agents may be used alone or in combination.

  The release agent is preferably added in an amount of 1 part by weight to 20 parts by weight with respect to 100 parts by weight of the binder resin. When the amount is less than 1 part by mass, it is difficult to obtain a desired releasing effect. When the amount exceeds 20 parts by mass, the dispersion in the toner is poor, and the toner adheres to the electrostatic image bearing member, and the developing member or cleaning member. As a result, the toner image tends to deteriorate.

  The toner of the present invention may be a magnetic toner or a non-magnetic toner, but is preferably a magnetic toner from the viewpoint of durability and stability in a high speed machine.

Magnetic materials used in the present invention include magnetic iron oxides including iron oxides such as magnetite, maghemite and ferrite, and other metal oxides; metals such as Fe, Co and Ni, or these metals and Al, Examples thereof include alloys with metals such as Co, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bf, Cd, Ca, Mn, Se, Ti, W, and V, and mixtures thereof. Conventionally, triiron tetroxide (Fe ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (ZnFe ₂ O ₄ ), iron yttrium oxide (Y ₃ Fe ₅ O ₁₂ ), cadmium iron oxide (Cd ₃ Fe ₂ O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), iron oxide copper (CuFe ₂ O ₄ ), lead iron oxide (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ) , Iron oxide neodymium (NdFe ₂ O ₃ ), iron barium oxide (BaFe ₁₂ O ₁₉ ), iron oxide magnesium (MgFe ₂ O ₄ ), iron oxide manganese (MnFe ₂ O ₄ ), iron lanthanum oxide (LaFeO ₃ ), iron Powder (Fe), cobalt powder (Co), nickel powder (Ni), and the like are known. A particularly suitable magnetic material is a fine powder of iron tetroxide or γ-iron sesquioxide. Further, the above-described magnetic materials can be selected and used alone or in combination of two or more.

  The magnetic material is preferably added in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  When used as a non-magnetic toner, the following pigments or dyes can be used as colorants.

  As the colorant, carbon black and other conventionally known pigments and dyes, one or more of them can be used.

  Examples of the dye include C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic green 6 etc. As pigments, chrome yellow, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, tartra gin lake, red mouth yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, benzidine orange G , Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmine 3B, Manganese Purple, Fast Violet B, Methyl Violet Lake, Bitumen, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue BC, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, There is § Lee Naru yellow green G and the like.

  When the toner of the present invention is used as a full-color image forming toner, the following colorants can be mentioned. Examples of the color pigment for magenta include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, 209, C.I. I. Pigment violet 19, C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned.

  Although the magenta pigment may be used alone, it is more preferable from the viewpoint of the image quality of a full color image to improve the sharpness by using a dye and a pigment together. Examples of the magenta dye include C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, C.I. I. Disper thread 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27, C.I. I. Oil-soluble dyes such as disperse violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, C.I. I. Basic violet 1,3,7,10,14,15,21,25,26,27,28 etc. are mentioned.

  Examples of the color pigment for cyan include C.I. I. Pigment blue 2, 3, 15, 16, 17, C.I. I. Bat Blue 6, C.I. I. Such as Acid Blue 45.

  Examples of the color pigment for yellow include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 35, 73, 83, C.I. I. Examples include bat yellow 1, 3, 20 and the like.

  The colorant is preferably 0.1 parts by mass or more and 60.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 50.0 parts by mass or less with respect to 100.0 parts by mass of the resin component.

  In the toner of the present invention, a charge control agent can be used to stabilize the triboelectric chargeability. Although the charge control agent varies depending on the type and physical properties of other toner particle constituent materials, generally, the toner particles are contained in an amount of 0.1 to 10.0 parts by mass per 100 parts by mass of the binder resin. Preferably, it is contained in an amount of 0.1 to 5.0 parts by mass. As such a charge control agent, one kind or two or more kinds can be used depending on the kind and use of the toner.

  Examples of toners that are negatively charged include the following. Organometallic complexes (monoazo metal complexes; acetylacetone metal complexes); metal complexes or metal salts of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids. In addition, examples of toners that are negatively charged include aromatic mono- and polycarboxylic acids and metal salts and anhydrides thereof; phenol derivatives such as esters and bisphenol. Among these, in particular, a metal complex or metal salt of an aromatic hydroxycarboxylic acid capable of obtaining stable charging performance is preferably used.

  Moreover, charge control resin can also be used and can also be used together with the above-mentioned charge control agent.

  If necessary, an external additive other than silica fine particles may be added to the toner of the present invention. Examples of such external additives include charging aids, conductivity-imparting agents, fluidity-imparting agents, anti-caking agents, release agents at the time of heat roller fixing, lubricants, abrasives, etc. Inorganic fine particles are exemplified.

  Examples of the lubricant include polyethylene fluoride powder, zinc stearate powder, and polyvinylidene fluoride powder. Among these, polyvinylidene fluoride powder is preferable. Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder. Of these, strontium titanate powder is preferable. Examples of the fluidity-imparting agent include titanium oxide powder and aluminum oxide powder. Among them, a hydrophobized one is preferable. Examples of the conductivity imparting agent include carbon black powder, zinc oxide powder, and antimony oxide powder.

  Furthermore, a small amount of white and black fine particles having opposite polarity can be used as a developing improver.

  The measurement of the BET specific surface area of the silica fine particles and the silica base is shown below.

  The BET specific surface area of the silica fine particles is measured according to JIS Z8830 (2001). A specific measurement method is as follows.

  As a measuring device, an “automatic specific surface area / pore distribution measuring device TriStar 3000 (manufactured by Shimadzu Corporation)” which employs a gas adsorption method by a constant volume method as a measuring method is used. Setting of measurement conditions and analysis of measurement data are performed using dedicated software “TriStar3000 Version 4.00” attached to the apparatus, and a vacuum pump, a nitrogen gas pipe, and a helium gas pipe are connected to the apparatus. The value calculated by the BET multipoint method using nitrogen gas as the adsorption gas is defined as the BET specific surface area in the present invention.

  The BET specific surface area is calculated as follows.

First, nitrogen gas is adsorbed on silica fine particles, and then the equilibrium pressure P (Pa) in the sample cell and the nitrogen adsorption amount Va (mol · g ⁻¹ ) of the silica fine particles are measured. The relative pressure Pr, which is a value obtained by dividing the equilibrium pressure P (Pa) in the sample cell by the saturated vapor pressure Po (Pa) of nitrogen, is plotted on the horizontal axis, and the nitrogen adsorption amount Va (mol · g ⁻¹ ) is plotted on the vertical axis. The adsorption isotherm is obtained. Next, a monomolecular layer adsorption amount Vm (mol · g ⁻¹ ), which is an adsorption amount necessary for forming a monomolecular layer on the surface of the silica fine particles, is determined by applying the following BET equation.
Pr / Va (1-Pr) = 1 / (Vm * C) + (C-1) * Pr / (Vm * C)
(Here, C is a BET parameter, which is a variable that varies depending on the measurement sample type, adsorbed gas type, and adsorption temperature.)

The BET equation is interpreted as a straight line with an inclination of (C-1) / (Vm × C) and an intercept of 1 / (Vm × C), where Pr is X axis and Pr / Va (1-Pr) is Y axis. Yes (this line is called a BET plot).
Straight line slope = (C-1) / (Vm × C)
Straight line intercept = 1 / (Vm × C)

  When the measured value of Pr and the measured value of Pr / Va (1-Pr) are plotted on a graph and a straight line is drawn by the least square method, the slope and intercept value of the straight line can be calculated. Vm and C can be calculated by solving the above slope and intercept simultaneous equations using these values.

Furthermore, the BET specific surface area S (m ² · g ⁻¹ ) of the silica fine particles is calculated from the Vm calculated above and the molecular occupation cross-sectional area (0.162 nm ² ) of the nitrogen molecule based on the following formula.
S = Vm × N × 0.162 × 10 ⁻¹⁸
(N is Avogadro's number (mole- ¹ ).)

  The measurement using this apparatus follows the “TriStar 3000 Instruction Manual V4.0” attached to the apparatus, and specifically, the measurement is performed according to the following procedure.

  Thoroughly weigh the tare of a dedicated glass sample cell (stem diameter 3/8 inch, volume about 5 ml) that has been thoroughly cleaned and dried. Then, about 0.1 g of silica fine particles are put into the sample cell using a funnel.

  The sample cell containing the silica fine particles is set in a “pretreatment apparatus Bacrepprep 061 (manufactured by Shimadzu Corporation)” connected with a vacuum pump and a nitrogen gas pipe, and vacuum degassing is continued at 23 ° C. for about 10 hours. In vacuum degassing, the gas is gradually degassed while adjusting the valve so that silica fine particles are not sucked into the vacuum pump. The pressure in the cell gradually decreases with deaeration and finally becomes about 0.4 Pa (about 3 mTorr). After completion of vacuum degassing, nitrogen gas is gradually injected to return the inside of the sample cell to atmospheric pressure, and the sample cell is removed from the pretreatment device. Then, the mass of the sample cell is precisely weighed, and the accurate mass of the silica fine particles is calculated from the difference from the tare. At this time, the sample cell is covered with a rubber plug during weighing so that the silica fine particles in the sample cell are not contaminated by moisture in the atmosphere.

  Next, a dedicated “isothermal jacket” is attached to the stem portion of the sample cell containing the silica fine particles. Then, a dedicated filler rod is inserted into the sample cell, and the sample cell is set in the analysis port of the apparatus. The isothermal jacket is a cylindrical member having an inner surface made of a porous material and an outer surface made of an impermeable material capable of sucking liquid nitrogen to a certain level by capillary action.

  Subsequently, the free space of the sample cell including the connection tool is measured. Free space is measured by measuring the volume of the sample cell with helium gas at 23 ° C., and then measuring the volume of the sample cell after cooling the sample cell with liquid nitrogen in the same manner using helium gas. Calculated from the difference in volume. Further, the saturated vapor pressure Po (Pa) of nitrogen is automatically measured separately using a Po tube built in the apparatus.

  Next, after performing vacuum deaeration in the sample cell, the sample cell is cooled with liquid nitrogen while continuing the vacuum deaeration. Thereafter, nitrogen gas is gradually introduced into the sample cell to adsorb nitrogen molecules on the silica fine particles. At this time, the adsorption isotherm is obtained by measuring the equilibrium pressure P (Pa) as needed, and the adsorption isotherm is converted into a BET plot. Note that the points of the relative pressure Pr for collecting data are set to a total of 6 points of 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30. A straight line is drawn from the obtained measurement data by the least square method, and Vm is calculated from the slope and intercept of the straight line. Furthermore, using the value of Vm, the BET specific surface area of the silica fine particles is calculated as described above.

  In order to produce the toner of the present invention, a binder resin, a colorant, and other additives 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, and an extruder. The toner of the present invention can be obtained by melt-kneading the mixture, cooling and solidifying, pulverizing and classifying to obtain toner particles, and further sufficiently mixing silica fine particles with the toner particles with a mixer such as a Henschel mixer.

  The following are mentioned as a mixer. Henschel mixer (made by Mitsui Mining); Super mixer (made by Kawata); Ribocorn (made by Okawara Seisakusho); Nauta mixer, turbulizer, cyclomix (made by Hosokawa Micron); Spiral pin mixer (made by Taiheiyo Kiko) A Ladige mixer (manufactured by Matsubo). Examples of the kneader include the following. KRC Kneader (manufactured by Kurimoto Iron Works); Bus Co Kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Nippon Steel); PCM kneader (Ikegai Steel mill); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); kneedex (manufactured by Mitsui Mining); MS-type pressure kneader, nider ruder (manufactured by Moriyama Seisakusho); Banbury mixer (Kobe Steel) (Made by the company). Examples of the pulverizer include the following. Counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Industrial Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.) SK; jet mill (manufactured by Seishin Enterprise Co., Ltd.); kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); turbo mill (manufactured by Turboe Industry Co., Ltd.); Examples of the classifier include the following. Classy, Micron Classifier, Spedic Classifier (manufactured by Seishin Enterprise); Turbo Classifier (manufactured by Nissin Engineering); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron); Elbow Jet (Japan) Iron Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Engineering Co., Ltd.); YM Microcut (manufactured by Yaskawa Corporation). Examples of the sieving apparatus used for sieving coarse particles include the following. Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Tokusu Kosakusha Co., Ltd.); Vibrasonic System (manufactured by Dalton Co.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Micro shifter (manufactured by Hadano Sangyo Co., Ltd.); circular vibrating sieve.

  Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on examples. However, the present invention is not limited to this.

<Example of production of a-SiC photoreceptor>
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 having a diameter of 80 mm, a length of 358 mm, and a thickness of 3 mm). A positively charged a-Si photosensitive member was produced under the conditions shown in Table 1 below. At that time, the charge injection blocking layer, the photoconductive layer, and the surface layer were formed in this order. Note that “*” in Table 1 indicates a variable value, and the high-frequency power, SiH ₄ flow rate, and CH ₄ flow rate at the time of preparing the surface layer were the conditions shown in Table 2 below.

  For the electrophotographic photoreceptor produced by the above method, evaluation of Si + C atom density, H atom ratio, and C atom ratio was performed under the above-mentioned conditions. The results are shown in Table 3.

The production method of the silica fine particles used in this example is shown below. A silica base material having a BET specific surface area of 300 m ² / g was used.

<Production Example of Silica Fine Particle 1>
20 parts by mass of dimethyl silicone oil (viscosity = 100 mm ² / s) is sprayed on 100 parts by mass of the silica base, and after stirring for 30 minutes, the temperature is raised to 200 ° C. while stirring and stirring is continued for 2 hours. The reaction was terminated. After completion of the reaction, crushing treatment was performed. Subsequently, 5 parts by mass of hexamethyldisilazane was sprayed inside with respect to 100 parts by mass of the silica raw material, and the silane compound treatment was performed in a fluidized state of the silica fine particles. After this reaction was continued for 60 minutes, the reaction was terminated and silica fine particles B-1 used in the present invention were obtained. Table 4 shows the physical properties of the silica fine particles 1 obtained. The carbon oil-based immobilization rate of silicone oil was calculated by measuring the immobilization rates of both the intermediate after the oil treatment and the silica fine particles.

<Example of production of silica fine particles 2>
Silica fine particles B-2 were obtained in the same manner as silica fine particles B-1, except that the amount of dimethyl silicone oil (viscosity = 100 mm ² / s) was changed to 15 parts by mass. Table 4 shows the physical properties of the obtained silica fine particles B-2.

<Example of production of silica fine particles 3>
Silica fine particles B-3 were obtained in the same manner as silica fine particles B-1, except that the treatment amount of dimethyl silicone oil (viscosity = 100 mm ² / s) was 25 parts by mass. Table 4 shows the physical properties of the obtained silica fine particle B-3.

<Example of production of silica fine particles 4>
Silica fine particles in the same manner as silica fine particles B-1, except that the treatment amount of dimethyl silicone oil (viscosity = 100 mm ² / s) was 26 parts by mass and 15 parts by mass of dimethyldichlorosilane was used instead of hexamethyldisilazane. B-4 was obtained. Table 4 shows the physical properties of the obtained silica fine particles B-4.

<Example of production of silica fine particles 5>
7 parts by mass of dimethyl silicone oil (viscosity = 100 mm ² / s) is sprayed on 100 parts by mass of the silica base, and after stirring for 30 minutes, the temperature is raised to 200 ° C. while stirring and stirring is continued for 2 hours. The reaction was terminated. After completion of the reaction, 6 parts by mass of dimethylsilicone oil was further sprayed to carry out the reaction in the same manner.

  Subsequently, 15 parts by mass of dimethyldichlorosilane was sprayed inside with respect to 100 parts by mass of the silica base material, and the silane compound treatment was performed in a fluidized state of the silica fine particles. After this reaction was continued for 60 minutes, the reaction was terminated and silica fine particles B-5 used in the present invention were obtained. Table 4 shows the physical properties of the obtained silica fine particles B-5.

<Example of production of silica fine particles 6>
Silica fine particles B-6 were obtained in the same manner as silica fine particles B-1, except that the treatment amount of dimethyl silicone oil (viscosity = 100 mm ² / s) was 25 parts by mass and the treatment temperature was 150 ° C. Table 4 shows the physical properties of the obtained silica fine particle B-6.

<Example of production of silica fine particles 7>
12 parts by mass of dimethyl silicone oil (viscosity = 50 mm ² / s) is sprayed on 100 parts by mass of the silica base, and after stirring for 30 minutes, the temperature is raised to 150 ° C. while stirring and stirring is continued for 2 hours. Then, the reaction was terminated, and silica fine particles B-7 used in the present invention were obtained. Table 4 shows the physical properties of the obtained silica fine particles B-7.

<Production Example of Silica Fine Particle 8>
Silica fine particles B-8 were obtained in the same manner as silica fine particles B-7, except that the treatment amount of dimethyl silicone oil (viscosity = 50 mm ² / s) was changed to 26 parts by mass. Table 4 shows the physical properties of the obtained silica fine particle B-8.

<Example of production of silica fine particles 9>
After spraying 5 parts by mass of dimethyl silicone oil (viscosity = 1000 mm ² / s) with respect to 100 parts by mass of the silica raw material, stirring was continued for 30 minutes, then the temperature was raised to 200 ° C. while stirring and stirring was continued for 2 hours The reaction was terminated. Subsequently, the same treatment was performed with 5 parts by mass of dimethyl silicone oil, and after completion of the reaction, the reaction was further carried out with 5 parts by mass of dimethyl silicone oil to obtain silica fine particles B-9 used in the present invention. Table 4 shows the physical properties of the obtained silica fine particles B-9.

<Production Example of Silica Fine Particle 10>
Silica in the same manner as silica fine particle B-1, except that the treatment amount of dimethyl silicone oil (viscosity = 100 mm ² / s) was 30 parts by mass, the treatment temperature was 100 ° C., and 15 parts by mass of hexamethyldisilazane was further used. Fine particles B-10 were obtained. Table 4 shows the physical properties of the obtained silica fine particle B-10.

<Production Example of Silica Fine Particle 11>
30 parts by mass of hexamethyldisilazane was sprayed inside with respect to 100 parts by mass of the silica raw material, and the silane compound treatment was performed in a fluidized state of silica fine particles. This reaction was continued for 60 minutes, and then the reaction was terminated.

Subsequently, 10 parts by mass of dimethyl silicone oil (viscosity = 50 mm ² / s) is sprayed on 100 parts by mass of the silica base, and after stirring for 30 minutes, the temperature is raised to 150 ° C. while stirring, and further 2 The reaction was terminated by stirring for a period of time to obtain silica fine particles B-11 used in the present invention. Table 4 shows the physical properties of the obtained silica fine particles B-11.

<Resin (C-1) Production Example>
・ Propylene oxide adduct of bisphenol A 34.0 mol%
(Average added mol number: 2.2 mol)
-Ethylene oxide adduct of bisphenol A 19.5 mol%
(Average added mol number: 2.2 mol)
・ Isophthalic acid 23.5mol%
N-dodecenyl succinic acid 13.5 mol%
-Trimellitic acid 9.5 mol%
The above monomer and dibutyltin oxide were added in an amount of 0.03 parts by mass based on the total acid components, and reacted with stirring at 22.0 ° C. for 6 hours under a nitrogen stream to obtain a polyester resin (C-1).

<Production Example of Toner 1>
Binder resin C-1 100 parts by mass Magnetic iron oxide particles (average particle size 0.15 μm) 75 parts by mass Fischer-Tropsch wax 4 parts by mass Charge control agent (Formula 2 below) 2 parts by mass

  The above materials were premixed with a Henschel mixer and then melt kneaded with a biaxial kneading extruder.

  The obtained kneaded product is cooled, coarsely pulverized with a hammer mill, pulverized with a jet mill, and the obtained finely pulverized powder is classified using a multi-division classifier utilizing the Coanda effect, D4) 6.8 μm negative triboelectrically chargeable toner particles were obtained. With 100 parts by mass of toner particles, 0.8 parts by mass of silica fine powder B-1 and 3.0 parts by mass of strontium titanate (number average particle size 1.2 μm) are externally added and mixed with a mesh having a mesh size of 150 μm. Sieve and negative triboelectric charge toner 1 was obtained.

<Production Examples of Toners 2 to 11>
As shown in Table 5, Toners 2 to 11 were obtained in the same manner as in Toner 1 except that the silica fine particles were changed.

[Example 1]
As a machine used for the evaluation, the process speed of a commercially available copying machine (iR-5075 manufactured by Canon) was modified to 600 mm / sec. As the transfer material, “office planner SK64g paper made by Canon” which is plain paper was used. The photoconductor 1 is attached to this evaluation machine, the toner 1 is filled, and a normal sheet is passed through a single-sided continuous paper of 500,000 using a test chart with a printing ratio of 5% in a normal temperature and humidity environment (23 ° C., 50% RH). Sheet durability was performed. At this time, the discharge current of the corona charger was adjusted so that the dark portion potential of the photoconductor was constant, durability was performed, and the following items were evaluated.

(Evaluation of wire contamination)
The diameter of the new wire was compared with the diameter of the wire formed by the silica thin film after endurance, and the thickness of the wire by the silica thin film after endurance was quantified as a ratio. Two types of wires were measured: a primary charger and a pre-transfer charger. The microscope used for the measurement was KH-3000V Hiscope Advanced (manufactured by HiROX) and measured at a magnification of 200 times. The evaluation results are shown in Table 6.
A (very good) 110% or less B (good) 110% or more and less than 120% C (normal) 120% or more and less than 130% D (slightly bad) 130% or more and less than 140%

(Vertical stripe evaluation of halftone images)
The initial halftone image and the halftone image after 500,000 sheets were visually evaluated, and the presence or absence of vertical streaks due to the wire contamination of the charger was evaluated. The evaluation results are shown in Table 6.
A (very good) Vertical stripes are not seen at all B (good) If you look carefully, there are slight vertical stripes C (normal) There is slight unevenness due to vertical stripes, but there is no problem on the image D (slightly bad) Unevenness due to vertical stripes

(Photoconductor shaving)
The evaluation method of photoconductor scraping is that the surface layer thickness of the photoconductor immediately after production is 9 points in the longitudinal direction in an arbitrary circumferential direction (0 mm, ± 50 mm, ± 90 mm, ± 130 points, ± 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 scraping amount was calculated from the average value of the 18 points.

The measurement method irradiates light perpendicularly on the electrophotographic photosensitive member surface 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. .
A (very good) 100 mm or less B (good) 100 mm or more and 250 mm or less C (normal) 250 mm or more and 400 mm or less D (somewhat bad) 400 mm or more

[Examples 2 to 12]
Evaluations were carried out in the same manner as in Example 1 for the combinations of the photoreceptors and toners shown in Table 6. The evaluation results are shown in Table 6.

[Example 13]
Evaluation was conducted in the same manner as in Example 1 except that the developing device was changed to that shown in FIG.

  This developing device includes a developing container 2200 (developing device main body) that contains toner, a first toner carrier 2310 and a second toner carrier 2320 that are installed above and below the photoconductor 2100, and a toner hopper 3000. , And agitating members 2800 and 2900 that convey the toner to the vicinity of the toner carriers 2310 and 2320, respectively.

  This developing device is provided with a magnetic doctor blade 2600 as a toner regulating member for the first toner carrier 2310 located on the upstream side in the rotation direction of the photosensitive member 2100, thereby restricting the toner coat of the first toner carrier 2310. I do. On the other hand, the second toner carrier does not include a magnetic doctor blade, and toner coat regulation is performed by a magnetic binding force or the like in the gap between the first toner carrier 2310 and the second toner carrier 2320. Compared to the case where there is only one toner carrier, the development opportunities are increased, so that it is suitably used for high-quality image development such as light printing.

[Comparative Examples 1 to 5]
Evaluations were carried out in the same manner as in Example 1 for the combinations of the photoreceptors and toners shown in Table 6. The evaluation results are shown in Table 6.

  1100: Deposition apparatus, 1110: Reaction vessel, 1111: Cathode electrode, 1112: Conductive substrate, 1113: Heater for heating substrate, 1114: Gas introduction pipe, 1115: High-frequency matching box, 1116: Gas pipe, 1117: Leak valve, 1118: Main valve, 1119: Vacuum gauge, 1120: High frequency power supply, 1121: Insulating material, 1123: Receiving base, 1200: Gas supply device, 1211 to 1215: Mass flow controller, 1221 to 1225: Cylinder, 1231 to 1235: Valve, 1241 to 1245: Inflow valve, 1251 to 1255: Outflow valve, 1260: Auxiliary valve, 1261 to 1265: Pressure regulator, 2100: Photoconductor, 2200: Developer container, 2310: First toner carrier, 2320: Second toner Carrier 2400, 2500: Magnet, 2600: toner regulating member, 2700: opening, 2800,2900: agitating member, 3000: toner hopper, alpha: rotation direction of the photosensitive member

Claims (3)

An electrostatic image carrier for carrying an electrostatic image is charged, an electrostatic image is formed on the charged electrostatic image carrier, the electrostatic image is developed, and the electrostatic image is developed on the electrostatic image carrier. An image forming method comprising a step of forming a toner image and transferring the toner image on the electrostatic image carrier to a transfer material,
The electrostatic charge image carrier is a photoreceptor in which at least a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide are sequentially laminated, and the atomic density of carbon atoms and carbon atoms in the surface layer of the photoreceptor The sum of the atomic densities of 6.60 × 10 ²² atoms / cm ³ or more,
The toner is toner having toner particles containing at least a binder resin and a colorant, and silica fine particles, the silica fine particles are at least treated with a silicone oil, and the carbon amount standard of the silicone oil is used. An image forming method, wherein the immobilization ratio is 30% by mass or more and 95% by mass or less.   In the surface layer of the photoreceptor, 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 is 0.30 or more and 0.45 or less, The image forming method according to claim 1.   The electrostatic image is developed using the first toner carrier and the second toner carrier, and the upstream first toner carrier in the rotation direction of the electrostatic image carrier is the downstream second toner. 3. The image forming method according to claim 1, wherein the toner amount on the carrier is regulated to a predetermined amount.

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