JP2011085828A - Toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method capable of acquiring a stable image quality without generating an image defect, even in use of various types of transfer materials. <P>SOLUTION: In this image forming method, an electrostatic charge image is formed on a charged electrostatic charge image carrier, and the electrostatic charge image is developed by a toner on a development sleeve to form a toner image, and the toner image is transferred to the transfer material on a transfer conveyance belt. The electrostatic charge image carrier is a photoreceptor formed by sequentially laminating a photoconductive layer, and a surface layer formed of hydrogenated amorphous silicon carbide, and the sum of the atomic density of silicon atoms and the atomic density of carbon atoms on a surface layer of the photoreceptor is ≥6.60×10<SP>22</SP>atom/cm<SP>3</SP>, and the toner is a magnetic toner having magnetic toner particles containing a binder resin and magnetic iron oxide, and inorganic fine powder, and a coefficient of dynamic friction of the toner to the photoreceptor is ≥0.25 and ≤0.55. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming method for developing an electrostatic image and a developer used in a toner jet.

  2. Description of the Related Art Image forming apparatuses using electrophotography have been strictly pursued for higher speed and higher reliability. For example, for printing high-definition images such as graphic designs, and for light printing that requires more reliability (print-on-demand applications that allow high-mix low-volume printing from document editing to copying and bookbinding on a personal computer) The image forming apparatus has begun to be used (hereinafter referred to as POD).

  When such an image forming apparatus is used as a POD application, the performance that is particularly required to be improved from the prior art includes high-quality print images, high-speed printability, high reliability, and high durability. Furthermore, there is a need to maintain stable transportability for transfer materials having various characteristics (for example, material, thickness, size) and to transfer the toner image on the photoreceptor onto the transfer material without excess or deficiency. .

  In Patent Document 1, the amount of penetration of the transfer belt with respect to the surface of the photosensitive member is controlled within a certain range, and the powder characteristics of the toner are controlled, so that the toner is agglomerated at the contact portion between the transfer belt and the photosensitive member. Proposals have been made to prevent the slippage of the transfer belt and effectively prevent contamination of the transfer belt. In particular, even when a print image is obtained continuously at high speed for a long period of time, it is possible to continue to maintain high-definition and high-quality print quality with high reliability. However, assuming light printing applications, the effect of preventing transfer dropout and the deterioration of image quality due to transfer (such as image roughness), that is, high image quality for transfer materials with various characteristics stably over the long term. There is room for further improvement in terms of maintaining print quality.

  In Patent Document 2, by controlling the relationship between the elastic deformation rate of the intermediate transfer member and the elastic deformation rate of the toner, it is possible to obtain a good transfer efficiency, prevent transfer loss and image quality deterioration due to transfer, and Proposals have been made that good cleaning properties can be obtained. However, there is room for improvement in order to increase the printing speed for light printing applications and to cope with various types of transfer materials.

  Japanese Patent Application Laid-Open No. 2004-228688 proposes that by controlling the shape factor of the toner and the molecular weight of the binder resin, it is possible to improve transfer dropout and transfer efficiency while maintaining high image density and latent image reproducibility. . Furthermore, Patent Document 4 discloses a technique that can achieve long-term image stability and transferability by utilizing the spacer effect of inorganic particles (silica particles) added to a toner. However, in any case, there is still room for improvement in order to increase the printing speed on the premise of light printing applications and to cope with various kinds of transfer materials.

  As described above, even when using various types of transfer materials, there are many technical problems to achieve image quality comparable to that of a printing press, and there is much room for improvement.

JP 2006-145811 A JP 2005-338808 A Japanese Patent Laid-Open No. 08-272139 JP-A-5-142849

  An object of the present invention is to provide a toner that solves the above problems.

  An object of the present invention is to provide an image forming method in which the above problems are solved.

  An object of the present invention is to provide a toner capable of obtaining a stable image quality without causing image defects even when various types of transfer materials are used.

The present invention charges an electrostatic image carrier for carrying an electrostatic image, forms an electrostatic image on the charged electrostatic image carrier, and develops the electrostatic image with toner on a developing sleeve. In the image forming method of forming a toner image and transferring the toner image to a transfer material on a transfer conveyance belt,
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 a magnetic toner having at least a binder resin, magnetic toner particles containing at least magnetic iron oxide, and at least an inorganic fine powder, and the dynamic friction coefficient of the toner with respect to the photoreceptor is 0.25 or more and 0.55 or less. The present invention relates to an image forming method.

In the present invention, an electrostatic charge image carrier for carrying an electrostatic charge image is charged, an electrostatic charge image is formed on the charged electrostatic charge image carrier, and the electrostatic charge image is formed by toner on a developing sleeve. A toner used in an image forming method of developing to form a toner image and transferring the toner image to a transfer material on a transfer conveyance belt,
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 and the sum of atom density is 6.60 × 10 ²² atoms / cm ³ or more, and the magnetic toner particles and the toner is at least containing at least a binder resin, magnetic iron oxide, be a magnetic toner containing at least inorganic fine powder And a toner having a dynamic friction coefficient of 0.25 to 0.55 with respect to the photosensitive member.

  According to the present invention, by using a magnetic toner in which the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer of the photoconductor is controlled and the dynamic friction coefficient of the toner with respect to the photoconductor is used, a wide variety can be obtained. Can maintain high-definition and high-quality print quality for a long period of time, even in the use state where high-speed and long-term continuous printing is performed on various types of paper, and a magnetic toner with a wide transfer latitude can be obtained. I can do it.

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 the schematic of the transcription | transfer process of this invention. FIG. 2 is a schematic cross-sectional view of an example mechanical pulverizer used in the toner pulverization step of the present invention. It is a schematic sectional drawing of the surface treatment apparatus used by this invention.

  In order to cope with various paper types at high speed for light printing applications, a transfer conveyance belt that can transfer regardless of the material, thickness, and size of the transfer material is indispensable. In order to prevent transfer misalignment even when printing speed is high using a transfer conveyance belt, the contact pressure between the transfer conveyance belt and the electrostatic charge image carrier (photosensitive member) is increased, and the adsorption area (transfer) to the photosensitive member is increased. Nip) needs to be increased. Further, since it is necessary to supply a transfer current to the photoconductor side at a contact portion with the photoconductor, it is necessary to press-contact with an arbitrary pressure.

  On the other hand, an amorphous silicon photoreceptor is preferably used in a high-speed machine that requires high durability stability and high reliability. Amorphous silicon photoreceptors have the advantages of high sensitivity over the entire visible light region, high surface hardness, and excellent durability, heat resistance and environmental stability. However, when it is intended to achieve a desired transfer performance in combination with the transfer belt because of its high hardness, the pressure applied locally at the contact portion becomes very high. As a result, there is a decrease in developability due to toner deterioration and the occurrence of image defects such as transfer loss.

  Thus, in order to achieve performance such as high durability and high image quality for light printing applications, a combination of a highly durable and hard photoconductor and transfer belt is essential, but in the past light printing applications None of these configurations can achieve the desired performance.

  In order to achieve these, the present inventors examined the behavior of the toner at the contact portion (transfer nip) of a photoconductor (particularly a high-hardness photoconductor such as an amorphous silicon drum). As a result, it has been found that the transfer efficiency can be controlled by controlling the interaction between the toner and the photoreceptor occurring between the transfer nips. The present inventors have found that it is important how to uniformly control the electrostatic action between the toner layer working between the transfer nips and the active sites present in the photoreceptor surface layer.

  That is, the present inventors have achieved a performance that solves the above-mentioned problem for the first time by controlling the friction coefficient of the toner with respect to the uniformly controlled photoconductor and the photoconductor with few highly active parts existing in the photoconductor surface layer. I have found that I can achieve it.

That is, according to the present invention, the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the surface layer (a-SiC surface layer) formed of hydrogenated amorphous silicon carbide of the photoreceptor is 6.60 × 10 ²² atoms / It is characterized by being cm ³ or more, and preferably 6.81 × 10 ²² atoms / cm ³ or more. By increasing the atomic density of silicon atoms and carbon atoms constituting the a-SiC surface layer, (1) making the bond between silicon atoms and carbon atoms difficult to break, and (2) reaction between carbon atoms and oxidizing substances. It is thought that the probability can be reduced. Further, since the bonding force of the constituent atoms of the surface layer is increased, a surface layer having a high hardness can be obtained, and as a result, high durability such as light printing can be achieved.

  It has been found that suppressing the oxidation of carbon atoms in the a-SiC surface layer is very important in achieving the desired performance. That is, the reaction between the carbon atom and the oxidizing substance breaks the bond between the silicon atom and the carbon atom in the surface layer, and a new dangling bond of the silicon atom is generated. It has been clarified that dangling bonds existing in the surface layer have a very high activity and thus cause a strong interaction between the toner and the photosensitive member, resulting in an influence during transfer.

When the sum of the atomic density of silicon atoms and the atomic density of carbon atoms in the a-SiC surface layer of the photoreceptor is less than 6.60 × 10 ²² atoms / cm ³ , the bond between silicon atoms and carbon atoms is likely to be broken, In addition, the reaction probability between the carbon atom and the oxidizing substance is increased. As a result, the carbon atom and the oxidizing substance react, the bond between the silicon atom and the carbon atom in the surface layer is cut, and a new dangling bond of the silicon atom is generated. Since the dangling bonds present in the surface layer are very active, a highly active portion and a low activity portion are localized in the surface layer of the photoreceptor. Furthermore, since these phenomena tend to progress as the usage time of the photoconductor increases, the tendency becomes more prominent as the end of the durability period is reached. If a transfer bias is applied in the transfer nip in such a state, it becomes difficult to uniformly transfer the toner onto the transfer material (transfer efficiency is lowered), and image defects such as transfer skipping are observed.

  An outline of an example of the photoreceptor used in the present invention will be described.

  FIG. 1 is a diagram 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 a 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 3110 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 ° 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, 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. The smaller the amount of gas supplied to the reaction vessel, the better the high frequency power. Moreover, the one where the pressure in a reaction container is high is good, and the one where the temperature of an electroconductive board | substrate is high is also good.

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.

  In the photoreceptor of 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 a-SiC surface layer is preferably 0.61 or more and 0.75 or less. .

  In the a-SiC surface layer, when the ratio of the number of carbon atoms to the sum of the number of silicon atoms and the number of carbon atoms is smaller than 0.61, particularly when a-SiC having a high atomic density is produced. The resistance of a-SiC may decrease. In such a case, the transferability when the material, thickness and size of the transfer material are changed is likely to change. In particular, the transfer efficiency of cardboard under high temperature and high humidity tends to decrease. Further, when the ratio of the number of carbon atoms to the sum of the number of silicon atoms and the number of carbon atoms is larger than 0.75, the reaction probability between the carbon atom and the oxidizing substance is increased. For this reason, the carbon atom and the oxidizing substance react, the bond between the silicon atom and the carbon atom in the surface layer is broken, and a new dangling bond of the silicon atom is easily generated. As a result, the interaction between the toner and the photosensitive member in the transfer nip is likely to be biased, and a phenomenon such as an image defect or a decrease in transfer efficiency is likely to occur.

  In the photoreceptor of 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 is preferably 0.30 or more and 0.45 or less. When hydrogen atoms are present in the a-SiC surface layer in an amount of less than 0.30, the optical band gap is narrowed in the a-SiC surface layer having a high atomic density, and the sensitivity is deteriorated due to increased light absorption. There is. As a result, there may be a case where image quality deterioration occurs particularly with a minute character. On the other hand, when hydrogen atoms are contained in the a-SiC surface layer in an amount of more than 0.45, the a-SiC surface layer tends to increase termination groups having many hydrogen atoms such as methyl groups. When a terminal group having a plurality of hydrogen atoms such as a methyl group is present in the a-SiC surface layer, a large space is formed in the structure of the a-SiC, and a bond between adjacent atoms is distorted. Let Such a structurally weak part is considered to be a very weak part against oxidation.

  Further, when a large amount of hydrogen atoms are contained in the a-SiC surface layer, it becomes difficult to promote the networking of silicon atoms and carbon atoms that are skeleton atoms in the a-SiC surface layer. As a result, the reaction probability between the carbon atom and the oxidant increases, so the carbon atom and the oxidant react, the bond between the silicon atom and the carbon atom in the surface layer is broken, and a new dangling bond of silicon atom is generated. It becomes easy. As a result, the interaction between the toner and the photosensitive member in the transfer nip is likely to be biased, and a phenomenon such as an image defect or a decrease in transfer efficiency is likely to occur.

  The method for measuring the atomic density and atomic ratio of the photoreceptor used in the present invention is shown below.

(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 volume ratio of the surface layer to the air layer of 8: 2 is used as a calculation model on the outermost surface. 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 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 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 the 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 at recoil angle: 30 °, aperture diameter: 8 mm + Slit.

  As described above, it is particularly important to control the reactivity of the surface layer of the photoconductor in the transfer nip in order to increase the printing speed for light printing applications and to support various types of transfer materials. It has been stated that. However, it is technically difficult to completely and uniformly control the surface layer of the photoconductor, and in order to solve the problem of the present invention, in addition to the control of the surface of the photoconductor, the toner that works between the transfer nips. It is important how to uniformly control the electrostatic action between the layer and the active sites present in the photoreceptor surface layer.

  As a result of intensive studies by the present inventors, electrostatic action between a toner layer that works easily between the transfer nips and an active site existing in the surface layer of the photosensitive member by controlling the dynamic friction coefficient of the toner with respect to the photosensitive member It was found that can be controlled.

  That is, the present invention is a magnetic toner in which the toner has magnetic toner particles containing at least a binder resin and magnetic iron oxide and at least inorganic fine powder, and the dynamic friction coefficient of the toner with respect to the photoreceptor is 0.25 or more and 0. .55 or less, preferably 0.25 or more and 0.50 or less.

  When the dynamic friction coefficient of the toner with respect to the photoreceptor is less than 0.25, it means that the electrostatic action between the toner layer working between the transfer nips and the active site existing on the photoreceptor surface layer is weak.

  In such a case, the transferability when the material, thickness and size of the transfer material are changed is likely to change. In particular, the transfer efficiency of cardboard under high temperature and high humidity tends to decrease. Further, in such a case, since the interaction between the toner and the photoconductor in the transfer nip is often biased, a phenomenon such as an image defect or a decrease in transfer efficiency is likely to occur.

  Further, when the dynamic friction coefficient of the toner with respect to the photoconductor is larger than 0.55, the electrostatic action between the toner layer working between the transfer nip and the active site existing in the surface layer of the photoconductor is very strong. means. If a transfer bias is applied in the transfer nip in such a state, it becomes difficult to uniformly transfer the toner onto the transfer material (transfer efficiency is lowered), and image defects such as transfer skipping are observed. Further, in such a case, since the interaction between the toner and the photoconductor in the transfer nip is often biased, a phenomenon such as an image defect or a decrease in transfer efficiency is likely to occur.

  As described above, the electrostatic friction between the toner layer acting between the transfer nip and the active site existing on the surface layer of the photosensitive member is made uniform by controlling the dynamic friction coefficient of the toner with respect to the photosensitive member within a certain range. It becomes possible to control. The above-mentioned problem can be solved only by having both such toner and a highly active portion existing in the surface layer of the photoconductor and having a uniformly controlled photoconductor.

The dynamic friction coefficient of the toner with respect to the photosensitive member was obtained by the following method.
1. Preparation of toner layer: A double-sided tape with a width of 100 mm is pasted on an experimental bench, and a toner is placed thereon. Thereafter, air is blown to make the toner layer uniform and single layer.
2. Measurement of tensile load: A photoconductor is placed on the toner layer coated on the double-sided tape, a spring balance is applied to one end, and the sample is pulled parallel to the experimental table. Pull the distance 500mm and read the stabilized value of the spring balance. Similarly, the tensile load is obtained with 0.2 kg, 0.5 kg, and 0.8 kg weights placed on the photoreceptor.
3. Calculation of dynamic friction coefficient: Calculate the dynamic friction coefficient from the slope of the load and tensile load plots.

  In the present invention, in order to uniformly control the electrostatic action between the toner layer working between the transfer nips and the active site existing in the surface layer of the photoreceptor, the contact area and contact opportunity of the toner with respect to the photoreceptor ( More preferably, the uniformity is controlled.

  Conventionally, it has been known that the toner shape is important for improving the transferability, and it has been proposed that the direction of increasing the circularity is particularly preferable. The present inventors have studied the relationship between toner shape and transfer performance in order to increase the printing speed on the premise of light printing applications and to cope with various types of transfer materials. As a result, the inventors have found the grounds that it is not sufficient to simply round the shape, which is the prior art, in order to cope with various types of transfer materials at a higher speed than before.

That is, the toner of the present invention has a weight average particle diameter of 5.0 μm or more and 9.0 μm or less, more preferably 5.0 μm or more and 8.0 μm or less. Further, BET specific surface area of the magnetic toner particles is 0.90 m ² / g or more 1.50 m ² / g or less, it is better and more preferably not more than 0.93 m ² / g or more 1.20 m ² / g.

  The weight average particle diameter is important for controlling the thickness of the toner layer in the transfer nip and the number of toner particles. When the weight average particle size is less than 5.0 μm, the number of toner particles is increased even if the thickness of the toner layer is the same, and the surface of the photoconductor and the toner is in contact with each other. It is easy to receive. If a transfer bias is applied in the transfer nip in such a state, it becomes difficult to uniformly transfer the toner to the transfer material (transfer efficiency may be reduced), and image defects such as transfer loss may occur. It can be seen, especially in the latter half of durability. When the weight average particle diameter is larger than 9.0 μm, the transferability between the thick paper and the thin paper is easily changed, but the image defect particularly on the thick paper tends to be remarkable, although it is hardly affected by the surface of the photoreceptor.

The BET specific surface area of the magnetic toner particles is important for controlling the contact opportunity with the photoreceptor in the transfer nip. When the BET specific surface area is less than 0.90 m ² / g, the contact point with the photoreceptor per toner particle decreases. As a result, although not easily affected by the surface of the photoreceptor, the transferability between the thick paper and the thin paper is greatly changed, and image defects particularly on the thick paper are likely to be remarkable. When the BET specific surface area is larger than 1.50 m ² / g, the contact point with the photoconductor per toner particle increases, so that it is easily affected by the reactivity of the photoconductor surface. If a transfer bias is applied in the transfer nip in such a state, it becomes difficult to uniformly transfer the toner to the transfer material (transfer efficiency may be reduced), and image defects such as transfer loss may occur. It can be seen, especially in the latter half of durability.

  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, the 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).

  The specific surface area of the magnetic toner particles in the present invention is determined by a BET specific surface area multipoint method using a known apparatus such as a degassing apparatus Bacuprep 061 (manufactured by Micromestic) or a BET measuring apparatus Gemini 2375 (manufactured by Micromesotic). Was used to determine the specific surface area. The outline of the measurement is described in the operation manual and is as follows.

  After measuring the mass of the empty sample cell, 2 g of the measurement sample is filled, for example. Furthermore, the sample cell filled with the sample is set in the degassing apparatus, and degassing is performed at room temperature for 24 hours. After completion of degassing, the mass of the entire sample cell is measured, and the accurate mass of the sample is calculated from the difference from the empty sample cell. Next, empty sample cells are set in the balance port and analysis port of the BET measuring apparatus. A dewar bottle containing liquid nitrogen is set at a predetermined position, and P0 is measured by a saturated vapor pressure (P0) measurement command. After the P0 measurement is completed, the sample cell prepared for degassing is set in the analysis port, and after inputting the sample mass and P0, the measurement is started by the BET measurement command. After that, the BET specific surface area is automatically calculated.

  The magnetic toner of the present invention has an average circularity of 0.930 to 0.970, more preferably 0.930 to 0.955. When the average circularity is less than 0.930, the contact point with the photoconductor per toner particle tends to increase, and it is easily affected by the reactivity of the photoconductor surface. If a transfer bias is applied in the transfer nip in such a state, it tends to be difficult to uniformly transfer the toner to the transfer material. When the average circularity is larger than 0.970, the contact point with the photosensitive member per toner particle tends to decrease. As a result, although not easily affected by the surface of the photoconductor, the transferability between the thick paper and the thin paper is greatly changed, and an image defect particularly on the thick paper may occur.

  The average circularity of the present invention is a circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel), and is 0.200 to 1.000. The average circularity of the toner analyzed by dividing it into 800 circularity ranges.

  The measurement principle of the flow-type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) is to capture flowing particles as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is captured by a CCD camera, and the captured image is subjected to image processing at an image processing resolution of 512 × 512 (0.37 × 0.37 μm per pixel), and the contour of each particle image is extracted, The projected area S, the peripheral length L, and the like are measured.

Next, the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity C is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. And is calculated by the following formula.
Circularity C = 2 × (π × S) 1/2 / L

  When the particle image is circular, the degree of circularity is 1, and the degree of unevenness on the outer periphery of the particle image increases, and the degree of circularity decreases. After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.

  The average circularity of the toner particles is measured by a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. 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 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.

  For the measurement, the flow type particle image analyzer equipped with “UPlanApro” (magnification: 10 ×, numerical aperture: 0.40) as an objective lens is used. It was used. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the circle equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is obtained.

  In measurement, automatic focus adjustment is performed using standard latex particles (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific) diluted with ion-exchanged water before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the examples of the present application, a flow-type particle image analyzer that has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, was used. Measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle diameter was limited to a circle equivalent diameter of 1.985 μm or more and less than 39.69 μm.

  Examples of the binder resin used in the present invention include the following. Polystyrene; homopolymer of styrene-substituted product such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic Acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer Styrene copolymers such as polymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenolic resins, natural modifications Phenolic resin, heaven Resin-modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin .

  In the present invention, in terms of effectively controlling the shape of the toner, a polyester resin in which over-pulverization does not easily occur, or a hybrid resin in which a polyester unit and a vinyl-based copolymer unit are chemically bonded, in which pulverizability is easily controlled. Is preferred.

  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。）
および式（２）で示されるジオール類。

(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, aliphatic alcohols are preferable from the viewpoint of charge control in the toner particles, and neopentyl glycol and 1,4-cyclohexanedimethanol are particularly preferable.

  Examples of the divalent acid component include the following dicarboxylic acids or derivatives thereof. Benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride or their anhydrides or lower alkyl esters thereof; alkyldicarboxylic 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.

  Furthermore, the mixing ratio of the polyester unit and vinyl copolymer unit of the hybrid resin used in the present invention is preferably 50/50 mass ratio or more. When the polyester unit is less than 50% by mass, over-pulverization tends to occur, and the shape of the toner tends to be difficult to control.

  Further, the binder resin has a peak molecular weight Mpt by GPC of tetrahydrofuran (THF) soluble component of 5000 to 10,000, a weight average molecular weight Mwt of 5000 to 300,000, and a ratio Mwt of the weight average molecular weight Mwt and the number average molecular weight Mnt. / Mnt is preferably 5 or more and 50 or less. When Mpt and Mwt are small and the distribution is sharp, high temperature offset is likely to occur. Further, when Mpt and Mwt are large and the distribution is broad, the low-temperature fixability is deteriorated.

  The glass transition temperature of the binder resin is 45 ° C. or more and 60 ° C. or less, more preferably 45 or more and 58 ° C. or less from the viewpoint of fixability and storage stability. Further, the softening temperature of the binder resin by a flow tester is preferably 120 to 150 ° C., more preferably 125 ° C. to 145 ° C., from the viewpoint of controlling the shape of the toner.

  These resins may be used by mixing two kinds of resins having different softening temperatures.

  The hybrid resin more preferably used as the binder resin in the present invention is a resin in which a polyester unit and a vinyl copolymer unit are chemically bonded directly or indirectly. The hybrid resin can be obtained by reacting the raw material monomer of the polyester unit and the raw material monomer of the vinyl copolymer unit simultaneously or sequentially.

In addition, the magnetic iron oxide used in the present invention has a magnetic property at 795.8 kA / m applied, a coercive force of 1.6 kA / m or more and 12.0 kA / m or less, a saturation magnetization, 50 Am ² / kg or more and 150 Am ² / kg or less ( preferably 50 Am ² / kg or more 100 Am ² / kg or less), residual magnetization 2Am ² / kg or more 20 Am ² / kg or less being preferred. The magnetic properties of magnetic iron oxide can be measured using a vibration type magnetometer such as VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.) under the conditions of 25 ° C. and an external magnetic field of 769 kA / m.

  Further, the number average particle diameter of the magnetic iron oxide of the present invention is preferably 0.05 μm or more and 0.60 μm or less, more preferably 0.10 μm or more and 0.40 μm or less.

  In addition, the magnetic iron oxide of the present invention is preferably subjected to a treatment to loosen the magnetic iron oxide by applying shear to the slurry during production for the purpose of improving the fine dispersibility in the toner particles.

  In the present invention, the amount of magnetic iron oxide contained in the toner is preferably 25% by mass or more and 45% by mass or less, more preferably 30% by mass or more and 45% by mass or less in the toner.

  In the present invention, a wax can be used as necessary to give the toner releasability. 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 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 wax; and deoxidation The fatty acid esters such as carnauba wax may be partially or wholly deoxidized. In addition, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, and seryl alcohol Saturated alcohols such as melyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylene bis stearic acid amide, ethylene biscaprin Saturated fatty acid bisamides such as acid amide, ethylene bislauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl Unsaturated fatty acid amides such as dipinamide, N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylenebisstearic acid amide, N, N-distearylisophthalic acid amide; calcium stearate, laur Grafted with fatty acid metal salts such as calcium phosphate, zinc stearate, magnesium stearate (generally called metal soap), and aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid. Examples of waxes include partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols, and methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils and the like.

  Examples of the release agent particularly preferably used in the present invention include aliphatic hydrocarbon waxes. As such an aliphatic hydrocarbon wax, for example, a low molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or a Ziegler catalyst under low pressure; Alkylene polymers obtained; synthetic hydrocarbon waxes obtained from the distillation residue of hydrocarbons obtained by the age method from synthesis gas containing carbon monoxide and hydrogen, and synthetic hydrocarbon waxes obtained by hydrogenating them; these aliphatics And hydrocarbon waxes separated by press sweating, solvent method, vacuum distillation and fractional crystallization.

  Examples of the hydrocarbon as the matrix of the aliphatic hydrocarbon wax include those synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often a multi-component system of two or more types) (for example, Hydrocarbon compounds synthesized by the Gintor method and Hydrocol method (using a fluidized catalyst bed); Up to several hundred carbon atoms can be obtained by the Age method (using an identified catalyst bed) in which many waxy hydrocarbons are obtained Hydrocarbons; hydrocarbons obtained by polymerizing alkylene such as ethylene with a Ziegler catalyst. Among such hydrocarbons, in the present invention, it is preferable that the hydrocarbon is a linear hydrocarbon having a small number of branches and a long saturation, and particularly a hydrocarbon synthesized by a method not based on polymerization of alkylene has a molecular weight distribution. Is also preferable.

  Specific examples that can be used include Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), high wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals), Sasol H1, H2, C80, C105, C77 (Sasol), 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), Unicid (Registered Trademark) 350, 425, 550, 700 (Toyo Petrolite Co., Ltd.), Wood Wax, Beeswax , Rice wax, candelilla wax, carnauba wax (available from Celerica NODA) That.

  The timing of adding the release agent may be added at the time of melt-kneading during toner production or may be at the time of binder resin production, 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 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When the amount is less than 1 part by mass, the desired release effect cannot be obtained sufficiently. When the amount exceeds 20 parts by mass, the dispersion in the toner is poor, so that the toner adheres to the photoreceptor and the surface of the developing member / cleaning member is contaminated. And the like, and the toner image is likely to deteriorate.

  In the toner of the present invention, a charge control agent can be used to stabilize the chargeability. The charge control agent varies depending on the type and physical properties of other toner particle constituent materials, but generally 0.1 to 10 parts by mass per 100 parts by mass of the binder resin is preferably contained in the toner particles. More preferably, 1 to 5 parts by mass are contained. As such a charge control agent, for example, an organometallic complex or a chelate compound is effective. Examples thereof include a monoazo metal complex; an acetylacetone metal complex; a metal complex or metal salt of an aromatic hydroxycarboxylic acid or an aromatic dicarboxylic acid; Is mentioned. In addition, examples of the toner that controls the toner to be negatively charged include aromatic mono- and polycarboxylic acids and metal salts and anhydrides thereof; phenol derivatives such as esters and bisphenol;

  Specific examples that can be used include Spiron Black TRH, T-77, T-95, TN-105 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, E-84, E- 88 (Orient Chemical Co., Ltd.), charge control resins can also be used, and the charge control agents described above can be used in combination.

In the toner of the present invention, the fluidity imparting ability to the toner particle surface as an inorganic fine powder is high, and the BET specific surface area with a smaller number average particle size of primary particles is 50 m ² / g or more and 300 m ² / g or less. It is characterized by using a property improver. As the fluidity improver, any fluidity improver can be used as long as the fluidity can be increased by adding the magnetic toner particles before and after the addition. For example, the following are mentioned. Fluorine resin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder; wet-process silica, fine-powder silica such as dry-process silica, these silicas by silane coupling agent, titanium coupling agent, or silicone oil Treated silica with surface treatment. A preferred fluidity improver is a fine powder produced by vapor phase oxidation of a silicon halogen compound, and is referred to as dry process silica or fumed silica. For example, the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen is utilized, and the reaction formula is as follows.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

  Further, in this production process, a composite fine powder of silica and another metal oxide obtained by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound may be used. The average primary particle diameter is preferably in the range of 0.001 μm to 2 μm, and particularly preferably silica fine powder in the range of 0.002 μm to 0.2 μm is used. good.

  Furthermore, it is preferable to use a treated silica fine powder obtained by hydrophobizing a silica fine powder produced by vapor phase oxidation of the silicon halogen compound. Among the treated silica fine powders, those obtained by treating the silica fine powder so that the degree of hydrophobicity titrated by a methanol titration test is in the range of 30 to 80 are particularly preferable.

  As a hydrophobizing method, it is applied by chemically treating with an organosilicon compound that reacts or physically adsorbs with silica fine powder. As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with an organosilicon compound. Examples of such organosilicon compounds include the following. Hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α- Chlorethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, 1 -Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyl Ludisiloxane and dimethylpolysiloxane containing 2 to 12 siloxane units per molecule and containing hydroxyl groups bonded to one Si at each terminal unit. These are used alone or in a mixture of two or more.

  The inorganic fine powder may be treated with silicone oil, or may be treated in combination with the hydrophobic treatment.

As a preferable silicone oil, one having a viscosity at 25 ° C. of 30 mm ² / s or more and 1000 mm ² / s or less is used. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil are particularly preferred.

  Examples of the method for treating silicone oil include the following methods. A method in which silica fine powder treated with a silane coupling agent and silicone oil are directly mixed using a mixer such as a Henschel mixer; a method in which silicone oil is sprayed on a silica fine powder as a base; or silicone in an appropriate solvent A method in which after dissolving or dispersing oil, silica fine powder is added and mixed to remove the solvent. More preferably, the silicone oil-treated silica is heated to 200 ° C. or higher (more preferably 250 ° C. or higher) in an inert gas to stabilize the surface coating after the silicone oil treatment.

  A preferred silane coupling agent is hexamethyldisilazane (HMDS).

  In the present invention, the silica is preferably treated by a method in which silica is treated with a coupling agent and then treated with silicone oil, or a method in which silica is treated with a coupling agent and silicone oil at the same time.

  The inorganic fine powder is used in an amount of 0.01 to 8 parts by weight, preferably 0.1 to 4 parts by weight, based on 100 parts by weight of the toner particles.

  Other external additives may be added to the toner of the present invention as necessary. For example, there are resin fine particles and inorganic fine particles that function as a charge auxiliary agent, conductivity imparting agent, fluidity imparting agent, anti-caking agent, release agent at the time of fixing with a heat roller, lubricant, and abrasive.

  Examples of the lubricant include polyethylene fluoride powder, zinc stearate powder, and polyvinylidene fluoride powder. Of these, polyvinylidene fluoride powder is preferred. Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder. These external additives can be sufficiently mixed using a mixer such as a Henschel mixer to obtain the toner of the present invention.

  In order to produce the toner of the present invention, binder resin, colorant, other additives, etc. are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill and then heat kneaded such as a heating roll, a kneader or an extruder. The toner of the present invention can be obtained by melt-kneading using a machine, pulverizing and classifying after cooling and solidification, and further mixing the desired additives as necessary with a mixer such as a Henschel mixer.

  Among them, for toner shape control, it is preferable to have a surface treatment step of passing through a surface treatment apparatus that continuously applies a mechanical impact force after pulverization or classification.

  For example, as a mixer, Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (Hosokawa Micron Co., Ltd.); Spiral pin mixer (Manufactured by Taiheiyo Kiko Co., Ltd.); Ladige mixer (manufactured by Matsubo Co., Ltd.), and kneaders: KRC kneader (manufactured by Kurimoto Iron Works Co.); bus co kneader (manufactured by Buss); (Manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); Mining company); MS pressure kneader, Nider Ruder (Moriyama Seisakusho); Banbury mixer (Kobe Steel) As a pulverizer, a counter jet mill, a micron jet, an inomizer (manufactured by Hosokawa Micron Co.); an IDS type mill, a PJM jet pulverizer (manufactured by Nippon Pneumatic Industry Co., Ltd.); a cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Examples of classifiers include: class seal, micron classifier, specick classifier (manufactured by Seishin Enterprise Co., Ltd.); turbo classifier (manufactured by Nissin Engineering Co., Ltd.); micron separator, turboplex (ATP), TSP separator (Hosokawa micron) (Made by company) Elbow Jet (manufactured by Nippon Steel & Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Engineering Co., Ltd.); YM Micro Cut (manufactured by Yaskawa Shoji Co., Ltd.) can be mentioned. Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Tokuju 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, etc.

  A method for measuring physical properties of the toner of the present invention is as follows. Examples described later are also based on this method.

[Method for measuring softening point of resin]
The softening point of the toner is measured by using a constant load extrusion type capillary rheometer “Flow Characteristic Evaluation Apparatus Flow Tester CFT-500D” (manufactured by Shimadzu Corporation) according to the manual attached to the apparatus. In this device, while applying a constant load from the top of the measurement sample with the piston, the measurement sample filled in the cylinder is heated and melted, and the molten measurement sample is pushed out from the die at the bottom of the cylinder, and the piston drop amount at this time A flow curve showing the relationship between temperature and temperature can be obtained.

  In the present invention, the “melting temperature in the 1/2 method” described in the manual attached to the “flow characteristic evaluation apparatus Flow Tester CFT-500D” is the softening point. The melting temperature in the 1/2 method is calculated as follows. First, ½ of the difference between the piston lowering amount Smax at the time when the outflow ends and the piston lowering amount Smin at the time when the outflow starts is obtained (this is X. X = (Smax−Smin) / 2). And the temperature of the flow curve when the amount of descending piston is the sum of X and Smin in the flow curve is the melting temperature in the 1/2 method.

  As a measurement sample, about 1.0 g of toner is compression-molded at about 10 MPa using a tablet molding compressor (for example, NT-100H, manufactured by NPA System) in an environment of 25 ° C. for about 60 seconds. A cylindrical shape having a diameter of about 8 mm is used.

The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rising start temperature: 50 ° C
Achieving temperature: 200 ° C
Measurement interval: 1.0 ° C
Temperature increase rate: 4.0 ° C./min
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Diameter of die hole: 1.0 mm
Die length: 1.0 mm

[Measurement of Glass Transition Temperature (Tg) of Resin and Melting Point of Wax]
The peak temperature of the maximum endothermic peak of the wax and toner is measured according to ASTM D3418-82 using a differential scanning calorimeter “Q1000” (manufactured by TA Instruments).

  The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium.

  Specifically, about 10 mg of toner is precisely weighed, put in an aluminum pan, and an empty aluminum pan is used as a reference. Measurement is performed at ° C / min. In the measurement, the temperature is once raised to 200 ° C., subsequently lowered to 30 ° C., and then the temperature is raised again. The maximum endothermic peak of the DSC curve in the temperature range of 30 ° C. to 200 ° C. in the second temperature raising process is defined as the maximum endothermic peak of the endothermic curve in the DSC measurement of the toner of the present invention. Further, a specific heat change is obtained in the temperature range of 40 ° C. to 100 ° C. during this temperature raising process. At this time, the intersection of the intermediate point line of the base line before and after the change in specific heat and the differential heat curve is defined as the glass transition temperature Tg of the binder resin.

<Measurement of magnetic properties of magnetic iron oxide particles>
Using a vibrating sample magnetometer VSM-P7 manufactured by Toei Industry Co., Ltd., measurement was performed at a sample temperature of 25 ° C. and an external magnetic field of 795.8 kA / m.

<Measurement of average primary particle diameter of magnetic iron oxide particles>
The average primary particle diameter is obtained by observing magnetic iron oxide particles with a scanning electron microscope (magnification 40000 times), measuring the ferret diameter of 200 particles, and determining the number average particle diameter. In this example, S-4700 (manufactured by Hitachi, Ltd.) was used as the scanning electron microscope.

<Measurement of arithmetic surface roughness (Ra) of developing sleeve>
The arithmetic average roughness Ra of the developing sleeve surface was measured using SURFCOM 1500DX manufactured by Tokyo Seimitsu Co., Ltd. based on the surface roughness of JIS-B0601 (2001). As measurement conditions, the measurement was performed at 3 points in the axial direction × 3 points in the circumferential direction = 9 points at a cutoff of 0.8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / s, and the average value was taken.

  Hereinafter, the transfer process in the present invention will be described with reference to the schematic view of FIG.

  The endless elastic transfer belt 2120 is supported by two or more rollers (two rollers, a drive roller 2130, and a driven roller 2140 in FIG. 2) arranged in parallel to each other in a direction substantially perpendicular to the transfer material conveyance direction. And is driven to rotate in the direction of the arrow by a drive motor (not shown). The endless elastic transfer belt 2120 conveys the transfer material 2170 in the direction of the arrow while the toner on the photoconductor 2110 is pressed onto the transfer material 2170 at a contact portion with the photoconductor 2110 (that is, the transfer nip portion). Transcript under.

In the present invention, the endless elastic transfer belt 2120 is preferably pressed against the photoreceptor side from the endless elastic transfer belt 2120 side with an appropriate pressure at the contact portion with the photoreceptor 2110. That is, as shown in FIG. 2, when the intrusion amount i (mm) of the endless elastic transfer belt 2120 with respect to the surface of the photoreceptor 2110 and the diameter of the photoreceptor 2110 are d (mm),
d × 0.05 <i ≦ d × 0.15
It is necessary to satisfy this relationship. As a result, it becomes easy to control the manner in which the toner and the photosensitive member contact between the transfer nips. At this time, keeping the toner layer forming state and the charging state of the toner image on the photoreceptor constant is very important for controlling the interaction between the toner and the photoreceptor between the transfer nips. In order to keep the state of the toner image on the photosensitive member constant, it is preferable to control the charged state of the toner layer on the developer carrying member (developing sleeve), and the arithmetic average surface roughness Ra of the developing sleeve is set to 0. It is preferable that the thickness is 3 μm or more and 1.5 μm or less.

  The material of the endless elastic transfer belt 2120 is preferably selected from materials having low hygroscopicity and stable resistance, such as chloroprene rubber, urethane rubber, EPDM rubber, silicone rubber, and epichlorohydrin rubber. In this case, the structure which has a base material is more preferable. The endless elastic transfer belt is accompanied by a bias roller 2150 as transfer charge applying means for applying a transfer bias by applying a transfer bias, and a high voltage power source 2160 for applying a voltage to the bias roller 2150. The bias roller 2150 is provided so as to contact the inside of the endless elastic transfer belt 2120 at a position slightly downstream of the transfer nip portion in the rotation direction of the endless elastic transfer belt 2120. The bias roller 2150 constitutes a contact electrode for applying a charge having a polarity opposite to the charge polarity of the toner developed on the photoreceptor 2110 to the endless elastic transfer belt. In the embodiment of the present invention, a bias of 6 kV in absolute value is applied on the side opposite to the charging polarity of the toner. The transfer charge applying means may be a charger using corona discharge or a brush-like charger. Further, the installation position of the transfer charge applying means is not limited to the downstream side in the rotational direction of the endless elastic transfer belt with respect to the transfer nip portion, and may be installed in the upstream direction.

  The schematic diagram of the transfer process shown in FIG. 2 has a structure in which the endless elastic transfer belt 2120 is always in pressure contact with the photoreceptor 2110 for the sake of simplicity of explanation. As a more specific embodiment, it is preferable to provide a so-called separation / contact function that forms a nip by pressing the transfer belt toward the photosensitive member only when transferring, that is, only when the transfer material contacts the photosensitive member. . In the present embodiment, the endless elastic transfer belt 2120 is used as a photosensitive member except when the image forming apparatus is in a starting operation and a stopping operation (that is, while the process speed of the apparatus main body (= photosensitive member surface speed) is unstable). It was press-contacted to the 2110 side. In this embodiment, the peripheral speed of the endless elastic transfer belt is set to be the same as the peripheral speed of the photoreceptor.

  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, this does not limit the embodiment of the present invention. The number of parts in the examples is part by mass.

<Example of production of binder resin B-1>
Cyclohexanedimethanol: 40.8 mol%
Neopentyl glycol: 18.5 mol%
Terephthalic acid: 33.8 mol%
Isophthalic acid: 6.9 mol%
Charge the above monomers together with an esterification catalyst into a 5 liter autoclave and attach a reflux condenser, moisture separator, N ₂ gas inlet tube, thermometer and stirrer at 230 ° C. while introducing N ₂ gas into the autoclave. A polycondensation reaction was performed. After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain a binder resin B-1 having a softening point of 138 ° C.

<Example of production of binder resin B-2>
Propoxylated bisphenol A (2.2 mol adduct): 25 mol%
Ethoxylated bisphenol A (2.2 mol adduct): 23.5 mol%
Terephthalic acid: 34.5 mol%
Trimellitic anhydride: 5.5 mol%
Adipic acid: 6.0 mol%
Acrylic acid: 4 mol%
Fumaric acid: 1.0 mol%
The polyester monomer is charged into a four-necked flask together with an esterification catalyst, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device are attached and stirred at 135 ° C. in a nitrogen atmosphere. In the present production example, fumaric acid was added in portions at the early and late stages of the reaction in order to obtain a desired crosslinked structure in the present invention. A vinyl copolymer monomer (styrene: 85 mol% and 2-ethylhexyl acrylate: 13 mol%), a mixture of benzoyl peroxide 2 mol% and fumaric acid: 0.5 mol% (as a polyester monomer) as a polymerization initiator was added dropwise. It was dripped over 4 hours from the funnel. Then, after reacting at 135 ° C. for 5 hours, the reaction temperature during polycondensation is raised to 210 ° C. to suppress gelation caused by both reactive substances due to an excessively high reaction temperature during polymerization. Went. After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain a binder resin B-2 having a softening temperature of 145 ° C.

<Example of production of binder resin B-3>
Propoxylated bisphenol A (2.2 mol adduct): 25.0 mol%
Ethoxylated bisphenol A (2.2 mol adduct): 25.0 mol%
Terephthalic acid: 36.2 mol%
Trimellitic anhydride: 13.8 mol%
Charge the above monomers together with an esterification catalyst into a 5 liter autoclave and attach a reflux condenser, moisture separator, N ₂ gas inlet tube, thermometer and stirrer at 230 ° C. while introducing N ₂ gas into the autoclave. A polycondensation reaction was performed. After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain a binder resin B-3 having a softening temperature of 120 ° C.

<Example of production of binder resin B-4>
The binder resin B-4 having a softening temperature of 150 ° C. was obtained by adjusting the reaction time of the formulation of the binder resin B-3.

<Example of production of binder resin (B-5L)>
Into a four-necked flask, 300 parts of xylene is charged, and the inside of the container is sufficiently replaced with nitrogen while stirring, and then heated to reflux.

  Under this reflux, a mixture of 76 parts of styrene, 24 parts of acrylate-n-butyl and 2 parts of di-tert-butyl peroxide (initiator 1) was added dropwise over 4 hours, and then held for 2 hours to conduct polymerization. Upon completion, a low molecular weight polymer solution (B-5L) was obtained.

<Example of production of binder resin (B-5H)>
Into a four-necked flask, 300 parts of xylene is charged, and the inside of the container is sufficiently replaced with nitrogen while stirring, and then heated to reflux.

  Under this reflux, first, 73 parts of styrene, 27 parts of acrylic acid-n-butyl, 0.005 part of divinylbenzene and 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane (initiator) 2, half-life 10 hours temperature; 92 ° C.) 0.8 part of the mixture is added dropwise over 4 hours. After all was added dropwise, the polymerization was completed by maintaining for 2 hours to obtain a binder resin (B-5H) solution.

<Manufacture of Binder Resin B-5>
In a four-necked flask, 200 parts of a xylene solution of the low molecular weight component (B-5L) (corresponding to 30 parts of the low molecular weight component) is added, and the temperature is raised and stirred under reflux. On the other hand, 200 parts (corresponding to 70 parts of high molecular weight component) of the above high molecular weight component (B-5H) solution is put into another container and refluxed. After the low molecular weight component (B-5L) solution and the high molecular weight component (B-5H) solution were mixed under reflux, the organic solvent was distilled off, and the resulting resin was cooled, solidified, pulverized and softened at 135 ° C. Binder resin B-5 was obtained.

<Manufacture of Binder Resin B-6>
In a four-necked flask, 300 parts of a xylene solution of the low molecular weight component (B-5L) (corresponding to 45 parts of the low molecular weight component) is charged, heated up and stirred under reflux. On the other hand, 157 parts of the high molecular weight component (B-5H) solution (corresponding to 55 parts of high molecular weight component) is charged into a separate container and refluxed. After the low molecular weight component (B-5L) solution and the high molecular weight component (B-5H) solution were mixed under reflux, the organic solvent was distilled off, and the resulting resin was cooled, solidified, pulverized and softened at a temperature of 119 ° C. Binder resin B-6 was obtained.

<Example of production of binder resin B-7>
The binder resin B-7 having a softening temperature of 153 ° C. was obtained by adjusting the reaction time of the formulation of the binder resin B-3.

<Manufacture of developing sleeve S-1>
The following raw materials were prepared.
-Resol type phenol resin: 300 parts (J-325 (Dainippon Ink & Chemicals, Inc .; trade name), methanol 40% contained; solid content 180 parts)
Graphitized particles: 54 parts (Mesocarbon microbeads obtained by heat-treating coal-based heavy oil were washed and dried, and then mechanically dispersed with an atomizer mill at 800 ° C. in a nitrogen atmosphere. Next, carbonization was performed by primary heat treatment, followed by secondary dispersion with an admixer mill, heat treatment at 2800 ° C. in a nitrogen atmosphere, and further classification, and volume average particle diameter of the obtained graphitized particles. 4.5 μm, graphitization degree P (002) 0.28)
Carbon black: 6 parts (Toka Black # 5500 (manufactured by Tokai Carbon Co., Ltd .; trade name), primary particle size 25 nm)
Methanol: 240 parts Unevenness-forming particles (Nikabeads PC1020 (manufactured by Nippon Carbon Co., Ltd.): 10 parts

  First, 54 parts of graphitized particles, 6 parts of carbon black, 10 parts of unevenness forming particles, and 80 parts of methanol were added to 100 parts of a resol type phenol resin solution (containing 40% methanol). Furthermore, glass beads having a diameter of 1 mm were added as media particles and dispersed in a horizontal sand mill to obtain a coating intermediate. 200 parts of the remaining resol type phenolic resin solution (containing 40% methanol) and 160 parts of methanol are added to this coating intermediate, glass beads having a diameter of 1 mm are added as media particles, and dispersed in a vertical sand mill to form a conductive resin. A layer forming coating solution (resin layer coating solution) was obtained.

  A conductive resin layer was formed on an aluminum substrate ground to an outer diameter of 24.5 mmφ by the air spray method using the resin layer coating solution. The coating area at this time was performed so that the conductive resin layer was formed at least in the development area. Subsequently, the conductive resin layer was cured by heating at 150 ° C. for 30 minutes in a hot air drying furnace, so that the developing sleeve 1 was produced. The arithmetic average roughness (Ra) of the surface of the conductive resin layer of the developing sleeve 1 produced at this time was 0.9 μm, and the layer thickness of the conductive resin layer was 8.2 μm.

<Manufacture of developing sleeves S-4 and 6>
The developing sleeve S-1 was surface-treated with a # 3000 polishing tape to adjust the arithmetic average roughness (Ra), and developing sleeves 4 and 6 were produced. The arithmetic mean roughness (Ra) of the surface of the conductive resin layer of the developing sleeve produced at this time was 0.4 μm for the sleeve 4 and 0.2 μm for the sleeve 6.

<Manufacture of developing sleeves S-2, 3, and 5>
Sleeves 2, 3, and 5 were produced in the same manner as the manufacturing method of the developing sleeve S-1. At this time, the arithmetic average roughness (Ra) was adjusted by shaking the added amount of the irregularity forming particles (Nikabead PC1020 (manufactured by Nippon Carbon Co., Ltd.) to 15, 20, and 30 parts. The arithmetic mean roughness (Ra) of the layer surface was 1.2 μm for the sleeve 2, 1.5 μm for the sleeve 3, and 1.7 μm for the sleeve 5.

<Manufacture of photoconductor Dr-1>
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, and the high frequency power, the SiH ₄ flow rate, and the CH ₄ flow rate during the surface layer preparation were set as shown in Table 2 below. Two electrophotographic photoreceptors were produced under each film forming condition. Using one electrophotographic photosensitive member out of the two electrophotographic photosensitive members prepared for each film formation condition, the sum of the atomic density of silicon atoms and the atomic density of carbon atoms (hereinafter referred to as “Si + C atomic 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 “H atom ratio”), the number of silicon atoms and the number of carbon atoms The ratio of the number of carbon atoms to the sum of the number of atoms (hereinafter referred to as C / (Si + C)) was measured, and the results are shown in Table 3. The unit of atomic density in Table 3 is “× 10 ²² atoms / cm ³ ”. Then, image evaluation was performed using another electrophotographic photosensitive member.

<Manufacture of photoconductors Dr-2 to 12>
Photoreceptors Dr-2 to 12 were produced under the conditions shown in Tables 1 and 2 in the same manner as the photoconductor Dr-1. Table 3 shows analysis results such as atomic density.

[Example 1]
Binder resin B-1 100 parts Magnetic iron oxide particles (average particle size 0.15 μm, Hc = 11.5 kA / m, σs = 88 Am ² / kg, σr = 14 Am ² / kg) 70 parts Fischer-Tropsch wax ( Melting point: 101 ° C.) 4 parts Charge control agent-b-1 2 parts

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

  The obtained kneaded product is cooled and coarsely pulverized with a hammer mill, and then finely pulverized with a mechanical pulverizer 301 shown in FIG. 3, and the obtained finely pulverized powder is used with a multi-division classifier utilizing the Coanda effect. Classified. Thereafter, the surface was modified by the surface modifying apparatus shown in FIG. 4 to obtain negatively chargeable magnetic toner particles having a weight average particle diameter (D4) of 7.1 μm.

In this embodiment, the pulverized surfaces of the rotor 3314 and the stator 3310 of the mechanical pulverizer 3301 are roughened so that the surface roughness, centerline roughness Ra is 6.0 μm, and the maximum roughness Ry is 32. .4 μm, 10-point average roughness was 21.5 μm, and antiwear treatment was performed by nitriding. Further, the rotor 3314 was pulverized with a peripheral speed of 117 m / s and a gap between the rotor 3314 and the stator 3310 of 1.3 mm. At this time, the outlet temperature T2 was 45 ° C. As a specific method of surface treatment, each rotor is rotated at a peripheral speed of 115 m / s and sucked to a blower air volume of 15.0 m ³ , and the surface treatment is performed with an input amount of 20 kg and a cycle time of 30 seconds. It was. At this time, the temperature at the exhaust outlet of the apparatus was 45 ° C.

Hydrophobic silica fine powder 1 [BET specific surface area 150 m ² / g as inorganic fine powder with respect to 100 parts of magnetic toner particles, 30 parts of hexamethyldisilazane (HMDS) and 10 parts of dimethyl silicone oil with respect to 100 parts of silica fine powder. In addition, 1.0 part of hydrophobizing treatment and 3.0 parts of strontium titanate fine powder (D50: 1.0 μm) as an abrasive were externally mixed and sieved with a mesh having an opening of 150 μm to obtain toner T-1. . Table 3 shows the physical properties of the toner and the friction coefficient of the toner T-1 with respect to the photosensitive Dr-1.

  The peripheral part of the transfer device of a commercially available digital copying machine iR5075 (75 cpm, a-Si photosensitive drum mounted, magnetic one-component jumping development method, manufactured by Canon Inc.) was modified to the transfer belt type shown in FIG. Further, the a-Si photosensitive member was replaced with the photosensitive member Dr-1 of the present invention, and the machine body process speed (= peripheral speed of the photosensitive drum) was modified to be 550 mm / sec. The print speed was 110 cpm.

  In this embodiment, the developing device used was changed to S-1 for the developing sleeve of the developing device mounted on the iR5075. As development conditions, a rotatable developing roller including a magnet roller is coated with the magnetic toner of the present invention on a thin layer, a +150 V DC bias, Vpp = 1.5 kV, frequency 2.7 kHz, duty 50% rectangular wave. An AC bias was applied. As the setting conditions of the developing device, the distance between the magnetic doctor blade and the developing roller is 220 to 230 μm, the distance from the developing roller to the surface of the a-Si photosensitive drum is set to 220 to 230 μm, and the non-contact developing condition is set. . The surface potential of the photosensitive drum was developed by setting VD to +380 to +420 V and VL to +40 to +60 V.

  The surface material of the transfer belt was chloroprene rubber, and the intrusion amount i of the transfer belt with respect to the photosensitive member was set to 5.9. In this embodiment, the peripheral speed of the transfer belt is set to be the same as the peripheral speed of the photoconductor.

  Using toner T-1, 23 ° C./50% RH environment (denoted as NN in Table 5), 23 ° C./5% RH environment (denoted as NL in Table 5), and 30 ° C./80% RH environment (Table 5) In this order, a durability test was performed in which a character image with an image ratio of 4% was continuously printed on an A4 landscape feed for 100,000 sheets each. At the end of each endurance test, evaluation of transfer dropout and transfer efficiency was performed. The evaluation was performed according to the following indicators. Table 5 shows the results.

<Evaluation of transfer omission>
At the end of the endurance test in each environment, an 8 mm square grid chart composed of repeated line widths of 200 μm, 500 μm, 1 mm, and 2 mm was printed on 250 g / m ² (A4) paper for both vertical and horizontal lines. Arbitrary 10 places on the second side print were observed visually and with a magnifying glass (× 30) and classified into the following evaluation ranks.
A: No transfer omission B: Transfer omission is confirmed in part of the field of view by observation using a 30 × magnifier D; Transfer omission is confirmed in part by visual observation D: Overall omission You can check the transfer gap

<Evaluation of transfer efficiency>
Each environment, the initial stage, and the transferability variation after endurance of 100,000 sheets were evaluated. Office planner A4 paper (basis weight 68 g / m ² ) and 250 g / m ² (A4) paper were used as transfer paper, and Rezac 66 (151 g / m ² ) was used as uneven paper. Transferability is calculated from the value obtained by subtracting the transfer residual toner on the solid black photoconductor and the pre-transfer toner with a polyester tape and stripping it off, then pasting it on the paper and subtracting the Macbeth density of the tape only on the tape. And evaluated.
A: Very good (90% or more)
B: Good (85% to less than 90%)
C: Normal (80% to less than 85%)
D: Bad (less than 80%)

[Examples 2 to 18, Comparative Examples 1 to 7]
Toner T-2 was prepared in the same manner as in Example 1 except that the type of binder resin and the content of magnetic iron oxide were the same as those shown in Table 3 and the production conditions shown in Table 4. Table 3 shows the physical properties of the toner and the friction coefficient of the toner T-1 against the photoreceptor Dr-1.

  Table 5 shows the results of similar evaluation. The penetration amount of the used photosensitive member, developing sleeve, and set transfer belt is as shown in Table 3.

  1100 Deposition apparatus, 1110 reaction vessel, 1111 cathode electrode, 1112 conductive substrate, 1113 heater for heating substrate, 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 supply, 1121 insulating material, 1123 cradle, 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, 2110 photoconductor, 2120 transfer belt, 2130 drive roller, 2140 driven roller, 2150 bias roller, 160 High-voltage power supply, 2170 Cleaning backup roller, 2180 Fur brush, 2190 Transfer material, 3212 Spiral chamber, 3219 Pipe, 3220 Distributor, 3222 Bag filter, 3224 Suction blower, 3229 Collection cyclone, 3301 Mechanical grinder, 3302 Powder Body outlet, 3310 Stator, 3311 Powder inlet, 3312 Rotating shaft, 3313 Casing, 3314 Rotor, 3315 First metering feeder, 3316 Jacket, 3317 Cooling water supply port, 3318 Cooling water outlet, 3320 Rear chamber 4,300 Casing, 4310 Classification rotor, 4320 Fine powder recovery, 4330 Raw material supply port, 4340 Liner (fixed body), 4350 Cold air inlet, 4360 Dispersion rotor (rotary body), 4370 Goods outlet, 4380 discharge valve, 4390 guide ring (guide means), 4400 square disc, 4410 first space, 4420 second space

Claims (7)

The electrostatic charge image carrier for carrying the electrostatic charge image is charged, an electrostatic charge image is formed on the charged electrostatic charge image carrier, and the electrostatic charge image is developed with toner on the developer carrier. An image forming method for forming a toner image and transferring the toner image to a transfer material on a transfer conveyance belt,
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 a magnetic toner having a magnetic toner particle containing at least a binder resin and magnetic iron oxide and an inorganic fine powder, and a dynamic friction coefficient of the toner with respect to the photoreceptor is 0.25 or more and 0.55 or less. An image forming method.   2. The image forming method according to claim 1, wherein the arithmetic mean roughness Ra of the developer carrying member is 0.3 μm or more and 1.5 μm or less. The relationship of the following formula (1) is satisfied, where i (mm) is the amount of penetration of the transfer / conveying belt into the photoconductor and d (mm) is the diameter of the photoconductor: 3. The image forming method according to any one of 2 above.
d × 0.05 <i ≦ d × 0.15 (1)   4. 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 photoreceptor is 0.61 or more and 0.75 or less. The image forming method according to any one of the above.   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 any one of claims 1 to 4. An electrostatic charge image carrier for carrying an electrostatic charge image is charged, an electrostatic charge image is formed on the charged electrostatic charge image carrier, and the electrostatic charge image is developed with toner on a developing sleeve to form a toner image. A toner used in an image forming method for transferring the toner image to a transfer material on a transfer conveyance belt,
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 and the sum of atom density is 6.60 × 10 ²² atoms / cm ³ or more, and the magnetic toner particles and the toner is at least containing at least a binder resin, magnetic iron oxide, be a magnetic toner containing at least inorganic fine powder A toner having a dynamic friction coefficient of 0.25 to 0.55 with respect to the photosensitive member. Claims weight average particle diameter of the magnetic toner is less 9.0μm or 5.0 .mu.m, BET specific surface area of the toner particles is equal to or less than 0.90 m ² / g or more 1.50 m ² / g Item 7. The toner according to Item 6.

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