JP4950567B2 - Image forming method - Google Patents

Description

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

  Conventionally, as an image forming method, many methods such as an electrostatic recording method, a magnetic recording method, and a toner jet method are known.

  In recent years, full-color copying machines, full-color printers, and the like have been demanded to enhance functions as black-and-white machines. In other words, even for a full-color copying machine or a full-color printer, monochrome image formation requires the same speed and high image quality as a black-and-white machine, and on that basis, a clear and high-quality full-color image can be obtained. There is a growing need for possible copiers. In such copiers and printers, the number of times black alone is used increases and inevitably increases the amount of toner consumed, so black toner in future full-color copiers will require further image reproducibility and durability stability. It is done.

  In addition, such a copying apparatus has been strictly pursued to be smaller, lighter, faster, and more reliable. For example, not only a general-purpose copying machine for copying original documents, but also for copying high-definition images such as digital printers or graphic designs as computer output, and more reliability is required. It has begun to be used for light printing (print-on-demand applications that allow high-mix, low-volume printing from document editing to copying and bookbinding on a personal computer). When light printing applications are assumed, the performance that is required to be improved from the conventional technology includes high-quality print images, high-speed printability, high reliability, and high durability. It is necessary to cope with a wide variety of transfer materials that are commonly used.

  An image forming apparatus that maintains stable transportability for transfer materials having various characteristics (for example, material, thickness, size), and transfers a toner image on a photoreceptor onto the transfer material without excess or deficiency, or A color image forming apparatus, a multicolor image forming apparatus, or a color image which outputs an image formed product in which a color image or a multicolor image is synthesized and reproduced by sequentially laminating and transferring a plurality of component color images of color image information or multicolor image information An image forming apparatus using an intermediate transfer belt is effective as an image forming apparatus having a forming function and a multicolor image forming function.

  Patent Documents 1 and 2 propose a method using an intermediate transfer belt having elasticity. According to this proposal, in the primary transfer portion between the first image carrier such as a photoreceptor and the intermediate transfer belt, and in the secondary transfer portion that transfers the image to the second image carrier, a sufficient transfer area, A so-called transfer nip can be secured, and partial transfer defects and color changes that have been a problem with conventional intermediate transfer belts that do not have elasticity, or the center of the line of the character image are not transferred, only the edge It has been proposed that it is possible to solve the problem of occurrence of “transfer dropout” in which the toner is transferred. However, assuming light printing applications, it is possible to maintain the high-quality print quality stably over a long period of time, such as a reduction in the effect of preventing transfer dropout and image quality deterioration due to transfer (such as image roughness). There is room for further improvement.

  In Patent Document 3, 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 transfer-induced image quality deterioration, 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.

  Patent Document 4 discloses a technique in which good cleaning characteristics can be obtained even in a full-color image forming apparatus having an amorphous silicon photoreceptor by controlling the particle size and the number of coarse particles of a magnetic toner. However, in this case as well, assuming light printing applications, the effect of preventing transfer dropout and the deterioration of image quality due to transfer (image roughness, etc.), that is, maintaining high-quality print quality stably over a long period of time are continued. There is room for further improvement in this regard.

  Further, Patent Documents 5, 6, and 7 disclose techniques that can achieve long-term image stability and transferability by utilizing the spacer effect of inorganic particles (silica particles) added to a toner. However, 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, there are many technical problems to achieve full-color quality equivalent to that of a printing press at a monochrome equivalent running cost or printing speed, and there is much room for improvement.

Japanese Patent Laid-Open No. 11-231683 JP-A-11-024429 JP 2005-338808 A JP 2004-354965 A JP-A-5-142849 JP 2002-108001 A JP 2003-322998 A

  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 in long-term use.

  The object of the present invention is achieved by the following.

That is , 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 using toner. In the image forming method, a toner image is formed, the toner image on the electrostatic charge image carrier is transferred to a transfer material via an intermediate transfer member, and the toner image on the transfer material is fixed by a heat fixing unit.
Intermediate transfer member, the maximum displacement amount of the intermediate transfer member against the load 9.8 × 10 ^-5 N (Sb) is in the range of 0.10～1.00Myuemu, with respect to the load 9.8 × 10 ^-5 N An endless belt having an elastic deformation rate Eb (%) (Eb = (Sb−Ib) × 100 / Sb) of 50% or more, where Ib is a plastic displacement amount of the intermediate transfer member,
The amount of penetration i of the intermediate transfer member with respect to the surface of the electrostatic charge image carrier at the portion in contact with the electrostatic charge image carrier is 0% <i ≦ 5% of the diameter d of the electrostatic charge image carrier,
The toner has negatively chargeable magnetic toner particles containing at least a binder resin and magnetic iron oxide, a volume-based median diameter (D50) of 1.24 to 3.00 μm, and a specific surface area of 1.0 to 4.7 m. ² / g, a negatively chargeable magnetic toner obtained by externally adding a fine silica powder,
The present invention relates to an image forming method, wherein the difference between the zeta potential of the silica fine powder and the zeta potential of the negatively chargeable toner particles at the pH of the aqueous dispersion of the negatively chargeable toner particles is 50 mV or less .

  In the image forming method of the present invention, the electrostatic charge image carrier preferably includes a conductive substrate, a photoconductive layer containing at least amorphous silicon and a surface protective layer containing amorphous silicon and / or amorphous carbon on the conductive substrate. .

  According to the present invention, an electrostatic image carrier for carrying an electrostatic image is charged, an electrostatic image is formed on the charged electrostatic image carrier, and the electrostatic image is developed to form a toner image. In an image forming method in which a toner image on an electrostatic charge image bearing member is transferred to a transfer material via an intermediate transfer member, and the toner image on the transfer material is fixed by a thermal fixing means, an intermediate having a specific elastic deformation rate A negatively chargeable magnetic toner particle containing at least a binder resin and magnetic iron oxide, and at least a volume-based median diameter (D50) and specific surface area. By using negatively chargeable magnetic toner with controlled silica fine powder, high-definition, high-quality images can be stably produced over a long period of time even when used in a variety of paper types for high-speed and long-term continuous printing. Can maintain the printing quality, it is possible to obtain a magnetic toner suitable for a wide full color applications transcriptionally Rachiteyudo.

An intermediate transfer belt capable of transferring multicolor images all at once regardless of the material, thickness, and size of the transfer material is indispensable for responding to various types of paper at high speed for full color light printing. In order to prevent transfer deviation even when the printing speed is high using an intermediate transfer belt, the contact pressure between the transfer belt and the electrostatic charge image carrier ( photoreceptor ) is increased, and the adsorption area (transfer nip) on the photoconductor is increased. ) Need 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. Furthermore, in the case of a system using an intermediate transfer belt, since it is necessary to perform transfer twice, the chance of applying pressure to the toner increases.

  On the other hand, in such a high-speed machine that requires high durability stability and high reliability, an amorphous silicon photoreceptor is preferably used. 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 the desired transfer performance is achieved in combination with the intermediate transfer belt because of its high hardness, the locally applied pressure at the contact portion becomes very high.

  Thus, in order to achieve performance such as high durability and high image quality for full-color light printing applications, a combination of a highly durable and high hardness photoconductor and an intermediate transfer belt is indispensable. However, there has been nothing that can achieve the desired performance in such a configuration for light printing applications.

  As a result of examining the relationship between the pressure applied to the contact portion (transfer nip) between the intermediate transfer belt and the photosensitive member (especially a high-hardness photosensitive member such as an amorphous silicon drum) and the toner, the binder resin and An intermediate transfer body having toner particles containing at least magnetic iron oxide and toners having at least inorganic fine powder, the particle diameter and specific surface area of the specific inorganic fine powder being controlled, and the toner having a specific elastic deformation rate It has been found that a good image without deterioration in image quality can be obtained over time while achieving high transfer efficiency and image quality equivalent to that of a printing press by using it in a configuration in which the amount of penetration into the electrostatic charge image carrier is controlled. In other words, in the case of obtaining a print image continuously at high speed for a long period of time, the use of a conventional technique for reducing toner aggregation is found to be insufficient to achieve both the transfer dropout phenomenon and high-speed developability. It came to. For example, when fine particles capable of obtaining a spacer action are added to the toner, the spacer particle release phenomenon always occurs, although there is a difference in degree. It became clear that there was. In addition, when adding some fine particles for the purpose of controlling the fluidity and chargeability of the toner, a method for controlling the toner charging characteristics to be low is often used, and in some cases, the reversal component is increased. It has been clarified that an electrostatic aggregating action tends to cause a transfer dropout or a transfer belt contamination phenomenon. These tendencies tend to appear remarkably with increasing print speed and print volume (number of prints output per unit period).

  From such a background, the present inventors have developed a mitigating effect on the toner aggregation phenomenon with respect to the pressure applied to the contact portion between the intermediate transfer belt and the photoconductor, and at the same time to achieve both durability stability during high-speed printing. Decided that it should not rely solely on the physical spacer effect, electrostatic apparent chargeability control, or fluidity control, and fundamentally reviewed the component materials used in the toner and proceeded with the study. .

That is, according to the present invention, a negatively chargeable magnetic toner particle containing at least a binder resin and magnetic iron oxide has a volume-based median diameter (D50) of 0.70 to 3.00 μm and a specific surface area of 1.0 to 10. It has a fine silica powder of 0 m ² / g. Developer by adding silica fine powder having extremely high electronegativity among inorganic fine powders to the negatively chargeable magnetic toner particles, that is, silica fine powder having almost the same negative chargeability as the negatively chargeable magnetic toner particles. It has been clarified that the surface is uniformly charged, and the effect of alleviating the electrostatic cohesive force between the developers caused by uneven charging is obtained.

In particular, by using silica fine powder having a volume-based median diameter (D50) of 0.70 to 3.00 μm and a specific surface area of 1.0 to 10.0 m ² / g, point contact with negatively charged toner particles is achieved. It is possible to control the existence state. Further, the contact frequency between the negatively chargeable toner particles can be reduced, and the interparticle cohesiveness can be greatly reduced. As a result, the ease of toner loosening against the pressure at the contact area between the intermediate transfer belt and the photosensitive member (the difficulty in packing the toner) is improved, and image quality deterioration such as transfer dropout during high-speed printing can be prevented. It became. Furthermore, in addition to the above effects, the spikes can be easily loosened when an electric field is applied during high-speed jumping development, that is, the toner is scattered, thereby reducing the toner loading (line height) on the electrostatic image. Therefore, even in a high-speed development system, a high-definition image with reduced transfer scattering can be obtained without depending on the environment.

  In addition, since particles having substantially the same chargeability are added, even when a silica fine powder as in the present invention having a relatively large particle size is added, the rate of liberation from the toner particle surface is low. As a result, the charge distribution becomes uniform as compared with the case where other inorganic particles are added, so both the primary transfer efficiency and the secondary transfer efficiency are improved. Further, since the amount of free components is not large, contamination of the intermediate transfer belt is reduced, and a decrease in density due to durability is suppressed.

  The toner of the present invention is characterized by having a silica fine powder having a volume-based median diameter (D50) of 0.70 to 3.00 μm, more preferably 0.70 to 2.00 μm, particularly preferably 0.70. 1.50 μm. When D50 is smaller than 0.70 μm, it is impossible to reduce the contact frequency between the toner particles. As a result, the cohesiveness deteriorates due to contact between the toner particles, and the ease of toner loosening (hardness of toner packing) with respect to the pressure at the contact portion between the intermediate transfer belt and the photosensitive member is reduced, and high-speed printing is performed. At times, image quality deterioration such as transfer dropout occurs. Further, since the charge distribution becomes non-uniform due to aggregation of the toner particles, the primary transfer efficiency tends to deteriorate particularly. Further, since the spikes are not easily loosened when an electric field is applied during high-speed jumping development, the amount of toner (line height) on the electrostatic charge image increases. As a result, scattering due to transfer increases particularly in a high-speed development system. On the other hand, when D50 is larger than 3.00 μm, the release from the toner particles increases, and the intermediate transfer belt is contaminated during high-speed development. As a result, not only does the density decrease through durability, but it also causes image quality degradation such as image dropout. Further, since it exists separately from the toner, the effect of reducing the cohesiveness between the toner particles is difficult to be exhibited, and transfer loss occurs.

  The particle size distribution in the present invention is measured by a laser diffraction / scattering particle size distribution measuring apparatus LA-920 (manufactured by HORIBA). As a measurement method, for example, about 30 mg of a sample is put in 100 ml of ion-exchanged water as a dispersion medium, and this dispersion is treated with an ultrasonic disperser for 1 minute to obtain a dispersion. This dispersion is dropped into the measurement cell so that the sample concentration is about 80% transmittance. The relative refractive index of the measurement sample and water is set according to the type of the sample, the volume-based particle size distribution is measured using the measurement device, and the median diameter (D50) is obtained.

Further, fine silica powder of the present invention is characterized by specific surface area of 1.0~10.0m ² / g, more preferably 1.0~8.0m ² / g, particularly preferably 2.0 to 8.0 m ² / g. When the specific surface area of the silica fine powder is smaller than 1.0 m ² / g, the release from the toner particles increases, and the intermediate transfer belt is contaminated during high-speed development. As a result, not only does the density decrease through durability, but it also causes image quality degradation such as image dropout. Further, since it exists separately from the toner, the effect of relaxing the cohesiveness between the toner particles becomes difficult to be exhibited, and the transfer omission occurs. Further, when the specific surface area of the silica fine powder is larger than 10.0 m ² / g, the negatively chargeable toner particles and the silica fine powder are in contact with each other, effectively reducing the cohesion between the toner particles. There is a tendency not to be able to let it. As a result, the cohesiveness deteriorates due to contact between the toner particles, and the ease of toner loosening (hardness of toner packing) with respect to the pressure at the contact portion between the intermediate transfer belt and the photosensitive member is reduced, and high-speed printing is performed. At times, image quality deterioration such as transfer dropout occurs. Further, when the specific surface area is larger than 10.0 m ² / g, the primary transfer efficiency tends to deteriorate because the toner charge distribution is non-uniform.

  The specific surface area of the silica fine powder in the present invention was measured by a gas adsorption method in which nitrogen gas was adsorbed on the sample surface using a specific surface area measuring device Gemini 2375 (manufactured by Shimadzu Corporation). The outline of the measurement is described in the operation manual issued by Shimadzu Corporation and is as follows. Prior to the measurement of the specific surface area, 2 g of the sample is put into a sample tube and evacuated at 100 ° C. for 24 hours. After evacuation, the sample weight was precisely weighed to obtain a sample. The specific surface area of the obtained sample was determined by the BET specific surface area multipoint method using the above specific surface area measuring apparatus.

  As the method for producing the silica fine powder of the present invention, a gas phase method in which a silicon compound such as metal silicon, a silicon halide, and a silane compound is reacted in a gas phase, and a silane compound such as alkoxysilane is water. / There are two types of wet methods: solvent removal from silica sol suspension obtained by hydrolysis and condensation reaction in organic solvent mixed system and drying to form particles. It is preferable to manufacture by a vapor phase method for ease.

Further, in the toner of the present invention, a hydrophobic inorganic fine powder having a high fluidity-imparting ability to the toner particle surface and a BET specific surface area of 50 to 300 m ² / g smaller than the number average particle diameter of primary particles is used in combination. Thus, it was found that the silica fine powder can be uniformly dispersed in the toner. When silica fine powder is not uniformly dispersed, toner deterioration tends to proceed in a high-speed development system. As a result, a decrease in density in the latter half of the endurance tends to occur.

By using a hydrophobic inorganic fine powder having a high ability to impart fluidity to the toner particle surface and a large BET specific surface area, the silica fine powder can be uniformly dispersed in the toner. When the BET specific surface area of the hydrophobic inorganic fine powder is smaller than 50 m ² / g, the silica fine powder is not sufficiently dispersed, which is not preferable. On the other hand, when the BET specific surface area of the hydrophobic inorganic fine powder is larger than 300 m ² / g, the toner is charged up to cause problems such as a decrease in density, which is not preferable.

  The hydrophobic inorganic fine powder is preferably both a so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass or the like.

  Hydrophobic treatment is performed by using silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, organic titanium compounds, or a combination of two or more. Can be used.

  In the following, the relationship with the powder characteristics of the toner layer under pressure in the image forming process will be described together with the image forming process.

  An example of an image forming apparatus suitable for the present invention is shown in FIG.

  This image forming apparatus is a copying machine or a laser beam printer using an electrophotographic process. The configuration and operation of the image forming apparatus shown in FIG. 1 will be briefly described below.

  A rotating drum type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 serving as a latent image carrying member is disposed inside the apparatus main body (hereinafter referred to as “inside the machine”). The photoconductor used in the present invention has a photoconductive layer provided on a cylindrical conductive substrate. However, particularly in light printing applications, the photoconductor containing amorphous silicon is used on the conductive substrate. It is preferable to use a photoreceptor having a layer and a surface protective layer containing amorphous silicon and / or amorphous carbon and / or amorphous silicon nitride. Amorphous silicon photoconductors, for example, have higher surface hardness and excellent abrasion resistance than organic photoconductors, and also have excellent environmental characteristics, that is, moisture resistance, so they have a longer life and are used for a long time. It is excellent in stability and reliability, and is suitably used when light printing applications are assumed. Further, in the present invention, when the amorphous silicon-based photoreceptor is provided with a surface protective layer containing amorphous carbon or amorphous silicon nitride, the environmental resistance, that is, the moisture resistance is improved, and the effect of releasing the toner is improved. For this reason, the effect of preventing transfer omission is more effectively exhibited.

  Regarding an example of a photoreceptor used in the present invention, comprising a conductive substrate and a photoconductive layer containing amorphous silicon and a surface protective layer containing amorphous silicon and / or amorphous carbon and / or amorphous silicon nitride on the substrate. A partial cross-sectional view is shown in FIG.

  As the conductive substrate 21 shown in FIG. 2, for example, aluminum (Al) is the most common, but chromium (Cr), molybdenum (Mo), gold (Au), indium (In), niobium (Nb), It is possible to use metals such as tellurium (Te), vanadium (V), titanium (Ti), platinum (Pt), lead (Pd), iron (Fe), and alloys thereof such as stainless steel. In addition, a transparent substrate such as glass or plastic, or an insulator such as ceramic is also made into a conductive substrate by conducting a conductive treatment on its surface, that is, the surface on the side where the photoconductive layer 23 is formed. Can do.

  Further, in the present invention, an amorphous silicon-based and / or amorphous carbon-based and / or amorphous silicon nitride-based surface protective layer 23 is provided on the photoconductive layer 22.

  The photoconductive layer 22 may be organic or inorganic as long as it has photoconductivity. However, as the inorganic photoconductive layer, for example, an amorphous film in which silicon atoms contain hydrogen atoms and / or halogen atoms is used. It is preferable to use a quality material (hereinafter abbreviated as a-Si (H, X)) as a main component. Or inorganic materials, such as a-Se, can be combined suitably.

  Moreover, it is preferable that the photoconductive layer 22 contains an atom for controlling conductivity as required. The atoms that control conductivity may be uniformly distributed in the photoconductive layer 22 or may be unevenly distributed. Examples of the atoms that control conductivity include so-called impurities in the semiconductor field, atoms belonging to Group III of the periodic table that give p-type conduction characteristics (hereinafter abbreviated as “Group III atoms”), or n-type conduction. An atom belonging to Group V of the periodic table giving characteristics (hereinafter abbreviated as “Group V atom”) can be used. Specific examples of the group III atom include boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). In particular, boron (B), aluminum (Al), and gallium. (Ga) is preferred. Specific examples of the group V atom include phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi), and phosphorus (P) and arsenic (As) are particularly preferable. By appropriately doping these impurities, the charging polarity of the amorphous photoreceptor can be determined.

  Further, in order to improve the photosensitive characteristics, the photoconductive layer 22 may have a plurality of layers such as a lower photoconductive layer 25 and an upper photoconductive layer 26. Although there is no limitation in particular as the film thickness of the photoconductive layer 22, about 15-50 micrometers is suitable from relationships, such as manufacturing cost.

  The surface protective layer 23 is a non-single crystal (preferably amorphous) material (a-SiC (H, X)) containing a silicon atom as a base and containing a carbon atom and, if necessary, a hydrogen atom and / or a halogen atom. A non-single crystal carbon (preferably amorphous carbon) (a-C (H, X)) containing a hydrogen atom and / or a halogen atom as necessary, a silicon atom as a parent, It is formed of a non-single crystal (preferably amorphous) material (a-SiN (H, X)) containing a nitrogen atom and, if necessary, a hydrogen atom and / or a halogen atom, or a combination thereof. In the present invention, since the photoreceptor has such a surface protective layer, the contact property with the transfer belt is improved, and the releasing effect on the surface of the photoreceptor is improved, thereby improving the transfer dropout. The action tends to be expressed more efficiently.

  Although there is no limitation in particular as the film thickness of the surface protective layer 23, about 0.05-2 micrometers is suitable from a viewpoint that what is necessary is just to exist at the minimum necessary for actual use. In addition, it is preferable to provide an interface layer (or antireflection layer) 27 in which the interface composition between the photoconductive layer 22 and the surface protective layer 23 is continuously changed, and to control the interface reflection in this portion. In addition, the surface of the conductive substrate 21 is preferably formed into a concavo-convex groove or dimple shape by cutting or the like. By adopting such a surface shape, it is possible to make it difficult to see the interference fringes caused by the reflection of the exposure light that has reached the surface of the conductive substrate 21, and the substrate of the film formed on the conductive substrate 21. The adhesion with 21 is also improved. Further, the shape of the conductive substrate may be as desired according to the driving method of the photosensitive member.

  Of course, in addition to these layers, various functional layers such as the charge injection blocking layer 24 as shown may be provided as necessary. For example, by providing the charge injection blocking layer 24 and appropriately selecting the dopant from group III atoms, group V atoms, etc., charge polarity control such as positive charge or negative charge becomes possible.

  The photosensitive drum 1 is rotationally driven in the direction of arrow R1 at a predetermined peripheral speed (process speed), and each image forming process to be described later is repeatedly performed on the surface of the photosensitive drum 1.

  The photosensitive drum 1 is charged to a predetermined polarity and a predetermined surface potential by a charger 2 such as a corona discharger in the rotation process in the direction of arrow R1, and then exposed to exposure means 3 (image formation based on color separation of a color original image). Color component image of target color image by receiving image exposure L by exposure optical system or scanning exposure optical system by laser scanner that outputs laser beam modulated in accordance with time series electric digital pixel signal of image information An electrostatic latent image corresponding to (for example, M (magenta) component image) is formed.

  An intermediate transfer belt is used as the intermediate transfer member.

The maximum displacement (Sb) with respect to the load 9.8 × 10 ⁻⁵ N of the intermediate transfer belt is 0.10 to 1.00 μm, preferably 0.15 to 0.90 μm. If it is smaller than 0.10 μm, the pressure applied to the toner layer when passing through the contact portion becomes too large, and even when the toner of the present invention is used, the ease of toner loosening with respect to the pressure at the contact portion between the intermediate transfer belt and the photosensitive member. (The difficulty in packing the toner) tends to decrease, and a part of the toner remains on the photoconductor without being transferred. As a result, transfer loss occurs. If it exceeds 1.00 μm, it means that a very soft elastic layer is used for the intermediate transfer member. When such an intermediate transfer belt is used, the life of the intermediate transfer member is remarkably reduced, which is not preferable in consideration of light printing applications.

The elastic deformation rate (Eb) with respect to the load 9.8 × 10 ⁻⁵ N of the intermediate transfer belt is 50% or more, preferably 55 to 90%. If it is less than 50%, the intermediate transfer belt is deformed when it passes through the contact portion, and it is difficult to return to the original state. Therefore, the contact time with the photosensitive member or the transfer material is shortened. Therefore, both the primary transfer efficiency and the secondary transfer efficiency tend to deteriorate.

The plastic displacement amount (Ib) with respect to the load 9.8 × 10 ⁻⁵ N of the intermediate transfer belt is not particularly limited in the present invention. However, since it is a value related to the elastic deformation rate of the intermediate transfer belt in the present invention, a preferable range is 0.05 to 0.50 μm.

  The maximum displacement amount of the intermediate transfer belt can be adjusted by the physical properties of the resin or rubber used for the elastic layer of the intermediate transfer belt, or the thickness of the surface layer. The amount of plastic displacement can be adjusted by the thickness of the elastic layer and the amount of additive. Further, since the elastic deformation rate is a value calculated from the maximum displacement amount and the plastic displacement amount, it can be within the above range by adjusting these. Specific physical properties and manufacturing methods will be described later.

The intermediate transfer belt (endless belt) 5 is suspended and stretched between a total of five rollers, one conductive roller 6 and four turn rollers 7a, 7b, 7c, 7d. The conductive roller 6 holds the intermediate transfer belt 5 in contact with the photosensitive drum 1 with a predetermined pressing force.

  The intermediate transfer belt of the present invention is preferably an intermediate transfer belt having an elastic layer. The elastic intermediate transfer belt is used for the following purposes. Since the elastic intermediate transfer belt is lower in hardness than the resin belt, it is deformed corresponding to the toner layer and the paper having poor smoothness at the transfer portion. In other words, the elastic intermediate transfer belt deforms following local irregularities, so that it can obtain good adhesion without excessively increasing the transfer pressure on the toner layer, and has flatness without character voids. A transfer image with excellent uniformity can be obtained even on paper with poor quality.

  The elastic intermediate transfer belt used in the present invention is composed of a material in which all or some of the layers have elasticity. Examples of such an elastic material include an elastic resin, an elastic material rubber, an elastomer, and the like. A surface layer (coat layer) may be provided on an elastic layer made of an elastic material, or a base material layer may be provided below the elastic layer.

  Examples of resins that can be used for the elastic layer of the elastic belt include polycarbonate, fluororesin (ETFE, PVDF), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, Styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) Styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene) -Phenyl methacrylate copolymer), Styrene resins (monopolymer or copolymer containing styrene or styrene-substituted product), methyl methacrylate resin, methacrylic acid such as tylene-α-chloroacrylic acid methyl copolymer, styrene-acrylonitrile-acrylic acid ester copolymer Acid butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, chloride Vinyl-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silicone Fat, ketone resins, ethylene - can be used ethyl acrylate copolymer, xylene resin and polyvinyl butyral resin, polyamide resin, one kind or two kinds or more selected from the group consisting of modified polyphenylene oxide resin. However, it is not limited to the said material.

  Elastic rubbers and elastomers include butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene ter Polymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, ricone rubber, fluorine rubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber , Selected from the group consisting of thermoplastic elastomers (eg, polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester, fluororesin) It is possible to use one kind or two or more kinds. However, it is not limited to the said material.

  The elastic intermediate transfer belt may contain a resistance value adjusting conductive agent. There are no particular restrictions on the conductive agent for adjusting the resistance value. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite Conductive metal oxides such as oxide (ATO) and indium oxide-tin oxide composite oxide (ITO) can be used. The conductive metal oxide may be coated with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate. Of course, the conductive agent is not limited thereto.

  The elastic intermediate transfer belt can be provided with a surface layer (coat layer) to improve releasability. The surface layer material is not limited, but it is preferable to improve the secondary transfer property by reducing the adhesion force of the toner to the surface of the transfer intermediate transfer belt. For example, materials that use one or more of polyurethane, polyester, epoxy resin, etc., and reduce surface energy and improve lubricity, such as fluororesin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. These powders and particles in which one type or two or more types are dispersed can be used. In addition, these powders and particles with different particle sizes can be dispersed and used. Also, heat treatment like a fluorine-based rubber material forms a fluorine-rich layer on the surface, reducing the surface energy. Can also be used.

  The manufacturing method of the elastic intermediate transfer belt is not limited. Centrifugal molding method in which material is poured into a rotating cylindrical mold to form a belt, spray coating method to form a thin film on the surface layer, and cylindrical mold material There are a dipping method in which it is dipped in the above solution, a casting method in which it is poured into an inner mold and an outer mold, and a method in which a compound is wound around a cylindrical mold and vulcanization polishing is performed. Moreover, it is possible to manufacture an elastic belt by combining a plurality of manufacturing methods.

  As a method for preventing the elastic belt from stretching, there are a method of forming a rubber layer in a core resin layer with little elongation, a method of putting a material for preventing elongation into the core layer, etc. Absent.

  In the present invention, it is preferable that the intrusion amount i of the transfer belt with respect to the surface of the photosensitive member at the contact portion between the transfer belt and the photosensitive member is in a range of 0% <i ≦ 5% of the photosensitive member diameter d. In the present invention, since the toner on the photosensitive member is pressed from the transfer belt side, the effect of preventing the transfer from falling out is exhibited. Although there is no restriction on the width, when the amount of penetration i of the transfer belt with respect to the surface of the photoreceptor exceeds 5%, the pressure applied to the toner layer when passing through the contact portion becomes too large, and the toner of the present invention is used. In this case, the ease of toner loosening against the pressure at the contact portion between the intermediate transfer belt and the photosensitive member (the difficulty in packing the toner) tends to decrease, and a part of the toner remains on the photosensitive member without being transferred. End up. As a result, transfer loss occurs. Further, if the amount of penetration i of the transfer belt with respect to the surface of the photoconductor exceeds 5%, there may be a case where image quality deterioration such as transfer blur is observed during high-speed printing operation.

  The intermediate transfer belt 5 is rotationally driven in the direction of arrow R5 with the same peripheral speed as that of the photosensitive drum 1, and a toner image formed on the photosensitive drum 1 (hereinafter referred to as "toner image") is applied to the conductive roller 6 by a bias power source. .) Is applied with a transfer bias having a polarity opposite to the toner charging polarity (minus in this embodiment).

  The intermediate transfer belt 5 is a dielectric film of polyester, polyethylene, or the like, or a composite layer type dielectric film having a back surface (inner surface side) of medium resistance rubber or the like lined with a conductor. The magenta toner image of the first color formed and supported on the surface of the photosensitive drum 1 described above passes through the transfer portion by an electric field formed by applying a transfer bias to the conductive roller 6, and then the intermediate transfer belt 5. The intermediate transfer is sequentially performed on the outer surface of the. At this time, the toner image formed and supported on the photosensitive member is subjected to a very high pressure at the contact portion between the photosensitive member and the intermediate transfer belt, and controlling the characteristics of the toner layer with respect to the pressure in this portion can control the image quality. , Greatly affects durability.

  The image forming apparatus includes a black (Bk) developing device 4a that is fixedly arranged on the upstream side in the rotation direction of the photosensitive drum 1 (the direction of the arrow R1) and the other three that are rotatably arranged on the downstream side. A rotating device 4b having a color developer is provided. The rotating device 4b includes three developing devices supported by the rotating body, that is, developing devices 402, 403, and 404 (for storing magenta (M), cyan (C), and yellow (Y) toners, respectively. Hereinafter, they are respectively constituted by “M developing unit 402, C developing unit 403, and Y developing unit 404”.

  Further, the Bk developing device 401 (hereinafter referred to as “Bk developing device”) fixed to the developing device 4a is fixed so as to divide these between the upstream exposure unit and the downstream rotating developing device 4b. And a developing sleeve 17 that is rotationally driven in the direction of the arrow R4a with respect to the rotational direction R1 of the photosensitive drum 1.

  Hereinafter, an image forming operation in the image forming apparatus of this embodiment shown in FIG. 1 will be described. FIG. 1 shows a state in which the magenta developing device 402 is in a standby state at the current position among the three developing devices in the rotary developing device 4b, and the cleaning device 8 is in contact with the photosensitive member. As a cleaning blade 8a and a cleaning auxiliary means, a magnet roller 8b is installed on the upstream side of the cleaning blade in the rotation direction of the photosensitive member.

  A magenta latent image of the first color is formed on the photosensitive drum 1 and development is performed in the state shown in FIG. The magenta toner image on the photosensitive drum 1 developed with magenta toner by the magenta developing unit 402 is sequentially intermediate-transferred onto the outer peripheral surface of the intermediate transfer belt 5 while rotating in the direction of arrow R1 (counterclockwise). The surface of the photosensitive drum 1 after the transfer of the first color magenta toner image is cleaned by the cleaning device 8.

  Thereafter, similarly, the second color cyan, the third color yellow toner and the fourth color black toner are developed, and four toner images (magenta, cyan, yellow) are formed on the outer surface of the intermediate transfer belt 5. , Black toner images) are superimposed and transferred to form a composite color toner image (mirror image) corresponding to the target color image.

  Next, a transfer material P such as paper is conveyed from the paper feed cassette 9 by the paper feed roller 10, and is supplied to the transfer portion formed by the transfer device 13 through the registration roller pair 11 and the transfer guide 12 at a predetermined timing. Sent.

  Here, a bias (negative in this example) having a polarity opposite to the transfer bias applied to the transfer device (that is, the same as the charging polarity of the toner) is applied to the conductive roller 6 from a bias power source as necessary. Is done. Further, a transfer bias having a toner charging polarity (minus in this example) and a reverse polarity (plus) is transferred onto the transfer material P fed at a predetermined timing by a bias power source when the toner image is transferred. 13 is applied. Also in this case, a large pressure is locally applied to the contact portion between the intermediate transfer belt 5 and the transfer device 13, and it is important to control the characteristics of the toner layer under the pressurized state also in the secondary transfer portion. Become.

  By repeating the above-described series of image forming processes, a composite color image is sequentially intermediately transferred onto the intermediate transfer belt 5, and these intermediate transferred composite color images are successively transferred to the transfer unit. The final transfer is performed on the transfer material P.

  When the transfer process is completed, a transfer bias (minus) of 0 V or the same polarity as the toner charging polarity (minus in this example) is applied to the intermediate transfer belt 5.

  The transfer material P onto which the toner image on the intermediate transfer belt 5 has been transferred through the transfer portion is introduced into the fixing device 15 through the conveyance guide 14, and the fixing roller 15a and the pressure roller 15b are heated and adjusted to a predetermined value. The toner image is subjected to fixing processing by being heated and pressurized by the above and is output as a final color image formed product.

  On the other hand, the intermediate transfer belt 5 after the toner image transfer is cleaned by a belt cleaning device 16. The belt cleaning device 16 is a cleaning device for the intermediate transfer belt 5, and is normally held in an inactive state with respect to the intermediate transfer belt 5. The outer surface of the intermediate transfer belt 5 is cleaned by the cleaning device 16 acting on the outer surface of the transfer belt 5.

  Depending on the outer peripheral length of the transfer belt 5, it is possible to carry two or more transfer materials P at a time and form two images at a time by one rotation.

  As described above, a negatively chargeable magnetic toner particle that controls the amount of penetration of the intermediate transfer belt having a specific elastic deformation rate into the electrostatic charge image carrier and contains at least a binder resin and magnetic iron oxide. Using a negatively chargeable magnetic toner having silica fine powder with at least a volume-based median diameter (D50) and a specific surface area controlled, printing operations can be performed continuously at high speed for a long period of time on a wide variety of paper types. Even in use, high-definition and high-quality print quality can be stably maintained for a long period of time, and a magnetic toner suitable for full-color applications with a wide transfer latitude can be obtained.

<Measurement of maximum displacement and plastic displacement of intermediate transfer member>
In the present invention, the maximum displacement amount and plastic displacement amount of the intermediate transfer member were measured with an ultrafine hardness meter ENT1100 manufactured by Elionix Corporation. The working indenter was a 100 μm × 100 μm square flat indenter, and the measurement environment was 27 ° C. and humidity 60%. A maximum load of 9.8 × 10 ⁻⁵ N is applied at a speed of 0.98 × 10 ⁻⁵ N / sec. After reaching the maximum load, leave it at that load for 0.1 sec. The amount displaced at that time was defined as the maximum displacement amount. Further, the load was unloaded at a speed of 0.98 × 10 ⁻⁵ N / sec through the maximum load, and the displacement when the load became zero was defined as the plastic displacement.

1. Measurement of Maximum Displacement and Plastic Displacement of Intermediate Transfer Member In measuring an intermediate transfer member, a measurement sample is adhered to a cell with a curable bond. Be careful not to let air or dust enter the bonding surface. This is to prevent the displacement of the sample from changing due to the influence of air or dust. Leave for at least one day until the bond dries. When the bond is dry, the cell is set in the apparatus and 100 points are measured from an arbitrary place. The remaining 80 points are used as data except 10 points for the maximum and minimum values of the measurement results. From the 80 points of measurement results, the average value is the maximum value and the minimum value is the maximum value of the intermediate transfer member. The amount of displacement and the amount of plastic displacement were determined.

  In the present invention, the absolute value of the difference between the zeta potential of the fine silica powder and the zeta potential of the negatively chargeable toner particles at the pH of the aqueous dispersion of negatively chargeable toner particles is preferably 50 mV or less. The zeta potential of the negatively chargeable toner particles at the pH of the aqueous dispersion when the negatively chargeable toner particles are dispersed in water represents the surface charge density at the pH of the powder of the toner particles. Therefore, in the present invention, it means that a fine silica powder having a surface charge density almost equivalent to the surface charge density on the surface of the toner particles is used. In general, it is known that when silica fine powder is added to toner particles, intermolecular force such as van der Waals force, electrostatic attractive force, liquid crosslinking force, and the like are generated. In the present invention, by controlling the charge density on the surface of the toner particles and the surface of the silica fine powder to be equivalent, the repulsive force can be applied in the direction to relieve the attractive force acting on the toner particles and the silica fine powder. It is considered that the intercohesive force could be reduced.

  When the difference between the zeta potentials of the negatively chargeable toner particles and the silica fine powder is larger than 50 mV, the above-described action for reducing the attractive force does not occur, and the interparticle cohesive force tends to increase. As a result, the cohesiveness deteriorates due to contact between the toner particles, and the ease of toner loosening against the pressure at the contact portion between the intermediate transfer belt and the photosensitive member (the difficulty in packing the toner) decreases, and at high speed printing. In this case, the image quality is liable to be deteriorated, such as transfer loss. The measurement method of the zeta potential measured by the present invention is shown below.

    The zeta potential of the toner particles and the silica fine powder was measured using an ultrasonic zeta potential measuring device DT-1200 (manufactured by Dispersion Technology). Pure water was used as a dispersion, and a 0.5 Vol% aqueous solution of toner particles and fine silica powder was prepared. If necessary, after adding 0.4% by mass of a nonionic dispersant that does not affect the zeta potential to the particle concentration, the mixture is dispersed for 3 minutes with an ultrasonic disperser, and then defoamed for about 10 minutes. Stir to make a dispersion. The pH of the supernatant was measured simultaneously with the measurement of the toner particles. When measuring the fine silica powder, this dispersion was titrated with 1N HCl or 1N KOH as necessary to adjust the pH value of the supernatant of the toner particles, and the zeta potential was measured using the above apparatus.

  The toner of the present invention has a uniaxial collapse stress of 1 kPa or less when the maximum consolidation stress of the toner is 0.1 kPa, a uniaxial collapse stress of 0.5 to 2.0 kPa when the maximum consolidation stress is 5 kPa, and the toner. The uniaxial collapse stress when the maximum consolidation stress is 20.0 kPa is preferably 2.0 to 6.0 kPa.

  Depending on the relationship between the maximum compaction stress (X) and the uniaxial collapse stress (U), the powder layer compacted with an arbitrary load is easily loosened, that is, the powder characteristics of the closely packed toner layer (cohesive force between toners). ) Can be discussed. The uniaxial collapse stress (U) is related to the packing state at the contact portion between the intermediate transfer belt and the photosensitive member. Therefore, the powder characteristics in a state where the pressure at the contact portion between the intermediate transfer belt and the photosensitive member is relatively small (for example, transfer scattering) due to the uniaxial collapse stress at the maximum consolidation stress of 0.1 kPa is discussed, and the maximum consolidation is discussed. With the uniaxial collapse stress when the stress is 20.0 kPa, it is possible to discuss the powder characteristics in a state where the pressure at the contact portion between the intermediate transfer belt and the photosensitive member is large (for example, hollowing out). Therefore, the latitude of the transfer can be evaluated by evaluating the transition of the uniaxial collapse stress at the maximum consolidation stress.

  When the uniaxial collapse stress at the maximum compaction stress of the toner of 0.1 kPa is larger than 1 kPa, it becomes difficult to obtain an optimal compaction state when the toner layer is pressed at the contact portion between the intermediate transfer belt and the photoreceptor. Image scattering tends to occur due to the applied pressure. Further, when the uniaxial collapse stress at the maximum consolidation stress of 20 kPa is smaller than 2.0, image transfer is less likely to occur, but image scattering is likely to occur due to the applied pressure. When the uniaxial collapse stress at the maximum consolidation stress of 20 kPa is larger than 6.0, the cohesiveness deteriorates due to the contact between the toner particles, and the toner loosens with respect to the pressure at the contact portion between the intermediate transfer belt and the photoreceptor. The ease (the difficulty with which the toner is packed) is lowered, and the image quality is liable to be deteriorated during transfer at high speed. As described above, by controlling the powder characteristics (inter-toner cohesive force) of the toner layer densely packed with toner, it is possible to design a toner with a wide latitude of voids and scattering. In this case, in order to design a toner having a wide latitude, it is preferable to control the uniaxial collapse stress at a maximum consolidation stress of 5 kPa, which is a substantially intermediate pressure, to 0.5 to 2.0 kPa.

  A shear scan TS-12 (manufactured by Sci-Tec) was used for evaluation of the cohesiveness of the toner in the compacted state. Share scan is Prof. Virendra M.M. The measurement is performed based on the principle of the Morcoulomb model described in 'CHARACTERIZING POWDER FLOWABILITY' (published 2002.1.24) written by Puri.

Specifically, the measurement was performed in a room temperature environment (23 ° C., 60% RH) using a linear shear cell (columnar shape, diameter 80 mm, capacity 140 cm ³ ) capable of linearly applying a shearing force in the cross-sectional direction. A developer is put in this cell, a vertical load is applied so that the pressure becomes 2.5 kPa, and a compacted powder layer is produced so as to be in the closest packing state in this vertical load (the pressure is automatically set in this compacted state). In the present invention, the measurement by the shear scan is preferable in that it can be detected without difference between individuals. Similarly, a compacted powder layer with a vertical load of 5.0 kPa and 10.0 kPa is formed. A test was conducted to apply shear force gradually while continuously applying the vertical load applied when forming the compacted powder layer to the sample formed at each vertical load, and to measure the fluctuation of the shear stress at that time. Determine the point. Judgment that the steady point has been reached is determined when, in the above test, the displacement of the shearing stress and the vertical displacement of the load applying means for applying the vertical load become small and both take stable values. Assume that a point has been reached. Next, the vertical load is gradually unloaded from the compacted powder layer that has reached the steady point, a fracture envelope (vertical load stress vs. shear stress plot) at each load is created, and the Y intercept and inclination are obtained. In the analysis by the Moul-Coulomb model, the uniaxial collapse stress and the maximum consolidation stress are expressed by the following equations, and the Y intercept becomes “cohesive force” and the inclination becomes “internal friction angle”.
Uniaxial collapse stress = 2c (1 + sinφ) / cosφ
Maximum consolidation stress = ((A− (A ² sin ² φ−τ _ssp ² cos ² φ) ^0.5 ) / cos ² φ) × (1 + sin φ) − (c / tan φ)
(A = σ _ssp + (c / tan φ), c = cohesive force, φ = internal friction angle, τ _ssp = c + σ _ssp × tan φ, σ _ssp = normal load at steady point)

  The uniaxial collapse stress and the maximum consolidation stress calculated for each vertical load are plotted (Flow Function Plot), and a straight line is drawn based on the plot. From this straight line, the uniaxial collapse stress at the maximum consolidation stress of 0.1 kPa, 5 kPa, and 20.0 kPa is obtained.

  As the fine silica powder used in the present invention, any silica fine powder having the above-mentioned characteristics can be used, but the following characteristics are preferred.

  The silica fine powder in the present invention preferably has an adsorption moisture content in the adsorption process at a relative humidity of 80% RH in the moisture absorption / desorption isotherm at 30 ° C., more preferably 0.01 to 3.00 mass%. ˜2.50 mass%, particularly preferably 0.10 to 1.50 mass%. When the amount of adsorbed moisture at a relative humidity of 80% RH is greater than 1.00% by mass, the amount of adsorbed moisture is large. In the case of such a silica fine powder, the chargeability and aggregation of the toner are deteriorated, so that the developability is deteriorated (concentration reduction and fog increase). On the other hand, when the amount of adsorbed moisture is lower than 0.01% by mass, it indicates that the silica fine powder has excessive hydrophobicity. If the hydrophobicity is excessively strong, the charge balance such as charge-up is lost, and the concentration tends to decrease and the fogging deteriorates.

  The adsorbed water content of the silica fine powder in the present invention is measured by an adsorption equilibrium measuring device (“EAM-02” manufactured by JT Toshi). This is a device that reaches solid-gas equilibrium under conditions where only the target gas (water in the present invention) exists, and measures the solid mass and vapor pressure at this time.

  The actual absorption / desorption isotherm is automatically measured by the computer from the measurement of the dry matter amount shown below and the degassing of dissolved air in the water to the measurement of the absorption / desorption isotherm. The outline of the measurement is described in the operation manual issued by JT Toshi Co., Ltd. and is as follows. In the present invention, water is used as the solvent liquid.

  First, about 5 g of silica fine powder was filled in the sample container in the adsorption tube, and then the thermostat temperature and the sample part temperature were set to 30 ° C. Thereafter, the air valves V1 (main valve) and V2 (exhaust valve) are opened to operate the evacuation unit, and the vacuum vessel is evacuated to about 0.01 mmHg to dry the sample. The mass when the mass change of the sample ceases is defined as “dry matter amount”.

  Since air is dissolved in water as a solvent solution, it is necessary to deaerate. First, water is put into a liquid reservoir, the evacuation unit is operated, and the air valves V2 and V3 (liquid reservoir valves) are alternately opened and closed to remove dissolved air. The above operation is repeated several times, and the deaeration ends when no more bubbles are seen in the water.

  Following the measurement of the amount of dry matter and deaeration of dissolved air in water, water vapor is introduced from the reservoir by closing the air valves V1, V2 and opening the air valve V3 while keeping the inside of the vacuum vessel under vacuum, Close the air valve. Next, the solvent vapor is introduced into the vacuum vessel by opening the air valve V1, and the pressure is measured by the pressure sensor. When the pressure in the vacuum vessel does not reach the set pressure, the above operation is repeated to set the pressure in the vacuum vessel to the set pressure. When equilibrium is reached, the pressure and mass in the vacuum vessel become constant, and the pressure and temperature at that time and the sample weight are measured as equilibrium data.

  By operating as described above and changing the pressure of the water vapor, the adsorption / desorption isotherm can be measured. In actual measurement, a relative vapor pressure for measuring the amount of adsorption is set in advance. For example, when the set pressure is 5%, 10%, 30%, 50%, 70%, 80%, 90%, and 95%, the “adsorption process” in the present invention refers to the amount of moisture adsorbed in order from 5%. Is the process of measuring the isotherm, and the "desorption process" is the process following the adsorption process. In contrast to the adsorption process, the moisture adsorption amount is measured while decreasing the relative vapor pressure from 95%. Show the process of doing.

In this apparatus, the pressure is set by the relative vapor pressure (% RH), and the adsorption / desorption isotherm is displayed by the adsorption amount (%) and the relative vapor pressure (% RH). The calculation formulas for the adsorption amount and relative vapor pressure are shown below.
M = {(Wk−Wc) / Wc} × 100
Pk = (Q / Q0) × 100
(Where M is the amount of adsorption (%), Pk is the relative vapor pressure (%), Wk (mg) is the sample weight, Wc (mg) is the dry matter weight of the sample, and Q0 (mmHg) is at the adsorption / desorption equilibrium. (Saturated vapor pressure of water obtained from the temperature Tk (° C.) of water by the Antoine equation, and Q (mmHg) represents the pressure measured as equilibrium data.)

  The colorant of the present invention is preferably magnetic iron oxide. By using magnetic iron oxide, which is a dielectric, as a colorant, toner agglomerates can be easily released when an electric field is applied. This makes it possible to reproduce faithfully without protruding a latent image. It is preferable to use magnetic iron oxide from the viewpoint of durability and stability. Furthermore, by including magnetic iron oxide in the toner particles, the surface resistance of the toner particles can be made equal to the surface resistance of the inorganic fine powder. As a result, charge transfer between the toner particle surface and the inorganic fine powder is facilitated, and the effect of alleviating the cohesiveness between particles can be expressed more effectively.

  The number average particle diameter of the magnetic iron oxide of the present invention is preferably 0.05 to 1.00 μm, more preferably 0.10 to 0.60 μm.

  As the magnetic iron oxide, iron oxide such as magnetite, maghemite, and ferrite is used. 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 to be contained in the toner is preferably 20 to 200 parts by mass, more preferably 30 to 150 parts by mass with respect to 100 parts by mass of the binder resin.
Examples of the binder resin used in the present invention include polystyrene; a styrene-substituted homopolymer such as poly-p-chlorostyrene and polyvinyltoluene; a styrene-p-chlorostyrene copolymer and a styrene-vinyltoluene copolymer. Styrene-vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ester Styrene copolymers such as ter copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers. Polymer; polyvinyl chloride, pheno Resin, natural modified phenolic resin, natural 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 and petroleum resin.

  In the present invention, the above binder resins can be used alone or in admixture of two or more and partially reacted.

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

  Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, 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０〜１０である。）、
および式（２）で示されるジオール類；

(Wherein 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);

が挙げられる。

Is mentioned.

  Examples of the divalent acid component include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or anhydrides thereof, lower alkyl esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid. Acids or anhydrides thereof, lower alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid and n-dodecyl succinic acid, or anhydrides, lower alkyl esters thereof; fumaric acid, maleic acid, citraconic acid, itaconic acid Dicarboxylic acids such as unsaturated dicarboxylic acids or anhydrides thereof, lower alkyl esters;

  Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. Is mentioned.

  Examples of the trivalent or higher polyvalent carboxylic acid component in the present invention include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5, 7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene Carboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, and their anhydrides, lower alkyl esters; formula (3)

（式中、Ｘは炭素数３以上の側鎖を１個以上有する炭素数５〜３０のアルキレン基又はアルケニレン基）
で表されるテトラカルボン酸等及びこれらの無水物、及び低級アルキルエステル等の多価カルボン酸類及びその誘導体が挙げられる。

(Wherein X is an alkylene group or alkenylene group having 5 to 30 carbon atoms having one or more side chains having 3 or more carbon atoms)
And polycarboxylic acids such as lower carboxylic esters and derivatives thereof.

  Examples of the vinyl monomer for producing the vinyl resin include the following.

  Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene Styrene and its derivatives such as: styrene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; halogenated such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride Vinyls: Vinyl acetate, vinyl propionate, vinyl benzoate Vinyl esters such as: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methacrylic acid Α-methylene aliphatic monocarboxylic acid esters such as phenyl, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate Acrylic esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone N-vinyl compounds such as these; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

  Further, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Alkenyl succinic acid half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester unsaturated dibasic acid half ester; dimethylmaleic acid, dimethyl fumaric acid unsaturated dibasic acid ester; acrylic acid, meta Α, β-unsaturated acids such as rillic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, the α, β-unsaturated acid and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Further, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

  In the toner of the present invention, the vinyl resin that can be used as the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. The crosslinking agent used in this case is an aromatic resin. Examples of the group divinyl compound include divinylbenzene and divinylnaphthalene; Examples of the diacrylate compound linked with an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, and 1,4-butanediol diacrylate. 1,5-pentanediol acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylates of the above compounds with methacrylate; linked by an alkyl chain containing an ether bond Diacrylate compounds For example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and the above compounds were replaced with methacrylate. Examples of the diacrylate compounds entangled with a chain containing an aromatic group and an ether bond include, for example, polyoxyethylene (2) -2,2-bis (4hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4hydroxyphenyl) propane diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate; For example, as over preparative compounds, trade name MANDA (Nippon Kayaku) is raised.

  Examples of the polyfunctional cross-linking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and those obtained by replacing the acrylate of the above compounds with methacrylate; And lucyanurate and triallyl trimellitate.

  These crosslinking agents can be used in an amount of 0.01 to 10 parts by mass (more preferably 0.03 to 5 parts by mass) with respect to 100 parts by mass of other monomer components.

  Among these crosslinkable monomers, those which are preferably used in the binder resin from the viewpoint of fixability and offset resistance are bonded with aromatic divinyl compounds (particularly divinylbenzene), chains containing aromatic groups and ether bonds. And diacrylate compounds.

  Examples of the polymerization initiator used in producing the vinyl resin include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile). 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1,1′- Azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxy Valeronitrile, 2,2-azobis (2-methylpropane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide Ketone peroxides such as oxide, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di -Tert-butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide, α, α'-bis (tert-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl Peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxy Carbonate, di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, tert-butyl peroxyacetate, tert-butylperoxyisobutyrate, tert-butylperoxyneodecanoate, tert-butylperoxy 2-ethylhexanoate, tert-butylperoxylaurate, tert-butylper Oxybenzoate, tert-butyl peroxyisopropyl carbonate, di-tert-butyl peroxyisophthalate, tert-butyl peroxyallyl carbonate, tert Amyl peroxy 2-ethyl hexanoate, di -tert- butyl peroxy hexahydro terephthalate, di -tert- butyl peroxy azelate and the like.

  Further, the binder resin has a peak molecular weight Mp of 5000 to 20000, a weight average molecular weight Mw of 5000 to 300,000, and a ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn by GPC of a tetrahydrofuran (THF) soluble component. Is preferably 5-50. When Mp and Mw are small and the distribution is sharp, a high temperature offset occurs. Further, when Mp and Mw are large and the distribution is broad, the desired low-temperature fixability cannot be obtained.

  The glass transition temperature of the binder resin is preferably 53 to 62 ° C. from the viewpoint of fixability and storage stability.

  In the toner of the present invention, the THF-insoluble content of the binder resin component when extracted for 16 hours is 15 to 50% by mass, preferably 15 to 45% by mass.

  Since the THF-insoluble component is an effective component for developing good releasability from a heating member such as a fixing roller, when applied to a high-speed machine, the amount of toner offset to the heating member such as a fixing roller is reduced. There is an effect to. When the amount is less than 15% by mass, the above effect is hardly exhibited. When the amount exceeds 50% by mass, not only the fixability is deteriorated but also the dispersibility of the raw materials in the toner is deteriorated and the chargeability is not uniform. Tend to be.

  Although the above resins may be used alone as the binder resin, two or more binder resins having different softening points may be mixed and used.

  In the present invention, a wax can be used as necessary to impart releasability to the toner. The wax has a low molecular weight because of ease of dispersion in the toner and high releasability. Hydrocarbon waxes such as polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax are preferably used, but one kind or two or more kinds of waxes may be used in a small amount as required. 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. Further, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, 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), Sazol H1, H2, C80, C105, C77 (Schumann Sazol), HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP- 12 (Nippon Seiki Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark), Unicid (registered trademark) 350, 425, 550, 700 (Toyo Petrolite Co., Ltd.), Kirou, Beeswax, rice wax, candelilla wax, carnauba wax (available at Celerica NODA Inc.) ) And the like.

  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. It is more preferable that 1-5 mass parts is 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 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, S-54, E-84, E- 88, E-89 (Orient Chemical Co., Ltd.), charge control resins can also be used, and the charge control agents described above can be used in combination.

  Other external additives may be added to the toner of the present invention as necessary. Examples thereof include resin fine particles and inorganic fine particles that function as a charging aid, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a release agent at the time of fixing with a heat roller, a lubricant, an abrasive, and the like.

  For example, examples of the lubricant include polyfluorinated ethylene powder, zinc stearate powder, polyvinylidene fluoride powder, and the like. Among these, polyvinylidene fluoride powder is preferable. 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.

  For example, as a mixer, Henschel mixer (made by Mitsui Mining); Super mixer (made by Kawata); Ribocorn (made by Okawara Seisakusho); Nauter mixer, turbulizer, cyclomix (made by Hosokawa Micron); 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); TEM type extruder (Manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho 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); an IDS type mill, a PJM jet pulverizer (manufactured by Nippon Pneumatic Industry); a cross jet mill (manufactured by Kurimoto Iron Works); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turboe Co., Ltd.); Super Rotor (manufactured by Nisshin Engineering Co., 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); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turboe Sangyo 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.

(1) Measurement of molecular weight distribution by GPC A column is stabilized in a heat chamber at 40 ° C., THF is flowed through the column at this temperature as a solvent at a flow rate of 1 ml per minute, and about 100 μl of a THF sample solution is injected and measured. . In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value and the count value of a calibration curve prepared from several types of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko KK is suitably used. The detector uses an RI (refractive index) detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, a combination of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko KK, or manufactured by Tosoh Corporation of _{TSKgel G1000H (H XL), G2000H} (H XL), G3000H (H XL), G4000H (H XL), G5000H (H XL), G6000H (H XL), G7000H (H XL), include a combination of TSKgurd column be able to.

  Moreover, a sample is produced as follows.

  Place the sample in THF and let stand at 25 ° C. for several hours, then shake well and mix well with THF (until the sample is no longer united), and let stand for more than 12 hours. At that time, the standing time in THF is set to 24 hours. After that, a sample processed filter (pore size 0.2 to 0.5 μm, for example, Mysori Disc H-25-2 (manufactured by Tosoh Corporation) can be used) is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

(2) Measurement of glass transition temperature of binder resin and toner Measuring device: differential scanning calorimeter (DSC), MDSC-2920 (manufactured by TA Instruments)
Measured according to ASTM D3418-82.

  The measurement sample is precisely weighed in an amount of 2 to 10 mg, preferably 3 mg. This is put into an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rise rate of 10 ° C./min at a temperature rise rate of 30 ° C. to 200 ° C. at normal temperature and humidity. The analysis is performed with a DSC curve in the temperature range of 30 to 200 ° C. obtained in the second temperature raising process.

  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.

<Example of production of binder resin 1>
Propoxylated bisphenol A (2.2 mol adduct): 25.0 mol%
Ethoxylated bisphenol A (2.2 mol adduct): 25.0 mol%
Terephthalic acid: 33.0 mol%
Trimellitic anhydride: 5 mol%
Adipic acid: 6.5 mol%
Acrylic acid: 3.5 mol%
Fumaric acid: 2.0 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: 84 mol% and 2 ethylhexyl acrylate: 14 mol%) and a mixture of 2 mol% of benzoyl peroxide as a polymerization initiator were added dropwise over 4 hours from the dropping funnel. Then, after reacting at 135 ° C. for 5 hours, the reaction temperature at the time of polycondensation was raised to 230 ° C. to perform a condensation polymerization reaction. After completion of the reaction, the reaction product was taken out from the container, cooled and pulverized to obtain a binder resin 1.
Various physical properties of the binder resin 1 are as shown in Table 1.

<Example of production of binder resin 2>
Terephthalic acid 31mol%
Trimellitic acid 7mol%
Propoxylated bisphenol A (2.2 mol adduct): 35 mol%
Ethoxylated bisphenol A (2.2 mol adduct): 27 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. A vinyl copolymer monomer (styrene: 84 mol% and 2 ethylhexyl acrylate: 14 mol%) and a mixture of 2 mol% of benzoyl peroxide as a polymerization initiator were added dropwise over 4 hours from the dropping funnel. Then, after reacting at 135 ° C. for 5 hours, the reaction temperature at the time of polycondensation was raised to 230 ° C. to perform a condensation polymerization reaction. After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain a binder resin 2.
Various physical properties of the binder resin 2 are as shown in Table 1.

<Example of production of binder resin 3>
Propoxylated bisphenol A (2.2 mol adduct): 46.8 mol%
Terephthalic acid: 34.8 mol%
Trimellitic anhydride: 11.8 mol%
Isophthalic acid: 5.6 mol%
Phenol novolac EO adduct: 1.0 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 3. Various physical properties of these resins are as shown in Table 1.

<Example of production of binder resin 4>
Propoxylated bisphenol A (2.2 mol adduct): 47.1 mol%
Terephthalic acid: 49.9 mol%
Trimellitic anhydride: 3.0 mol%
Charge the above monomers together with an esterification catalyst into a 5 liter autoclave and attach a reflux condenser water separator, N ₂ gas inlet tube, thermometer and stirrer, and heat at 230 ° C. while introducing N ₂ gas into the autoclave. A condensation reaction was performed. After completion of the reaction, it was taken out from the container, cooled and pulverized to obtain a binder resin 4. Various physical properties of these resins are as shown in Table 1.

<Example of production of binder resin (5L)>
Into a four-necked flask, 300 parts by mass 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 by mass of styrene, 24 parts by mass of acrylate-n-butyl and 2 parts by mass of di-tert-butyl peroxide was added dropwise over 4 hours, and then held for 2 hours to complete the polymerization. A low molecular weight polymer solution (5 L) was obtained.

<Example of production of binder resin (5H)>
Into a four-necked flask, 300 parts by mass 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 by mass of styrene, 27 parts by mass of acrylate-n-butyl, 0.005 parts by mass of divinylbenzene, and 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane. 0.8 parts by mass of the mixed solution is dropped over 4 hours. After all was added dropwise, the polymerization was completed by maintaining for 2 hours to obtain a binder resin (5H) solution.

<Manufacture of binder resin 5>
In a four-necked flask, 200 parts by mass of a xylene solution of the low molecular weight component (5 L) (corresponding to 30 parts by mass of the low molecular weight component) is added, and the temperature is raised and stirred under reflux. On the other hand, 200 parts by mass of the high molecular weight component (5H) solution (equivalent to 70 parts by mass of the high molecular weight component) is charged into another container and refluxed. After the low molecular weight component (5 L) solution and the high molecular weight component (5H) solution were mixed under reflux, the organic solvent was distilled off, and the resulting resin was cooled, solidified, and pulverized to obtain a binder resin 5. Various physical properties of the binder resin are as shown in Table 1.

<Production example of silica fine powder 1>
A mixed gas having a volume ratio of argon and oxygen of 3: 1 is introduced into the reaction vessel to replace the atmosphere. Oxygen gas is supplied into this reaction vessel at 40 (m ³ / hr) and hydrogen gas at 20 (m ³ / hr), and an ignition device is used to form a combustion flame composed of oxygen-hydrogen. Next, a metal silicon powder as a raw material is charged into the combustion flame with a hydrogen carrier gas having a pressure of 5 kg / cm ³ to form a dust cloud. This dust cloud is ignited by a combustion flame and causes an oxidation reaction by dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled to obtain silica fine powder 1. Various physical properties of the silica fine powder are as shown in Table 2.

<Production example of silica fine powder 2>
A fine silica powder 2 was obtained in the same manner as in Production Example 1 except that the carrier gas pressure was 12 kg / cm ³ in Production Example 1. Various physical properties of the silica fine powder are as shown in Table 2.

<Production example of silica fine powder 3>
After adding 14 L of ethanol and 1.5 kg of 28% aqueous ammonia solution to a 30 L glass reactor equipped with a stirrer, a dripping port and a thermometer, ammonia gas was blown into the reactor and 0.26 kg was absorbed and mixed. Prepared. The mixed solution was adjusted to 10 ° C. ± 0.5 ° C. and stirred, so that a mixed solution of 1,130 g of tetraethoxysilane as a silane compound and 63 g of 3-aminopropyltriethoxysilane as a silane compound was adjusted to a temperature in the reaction vessel. While maintaining the temperature at 25 ° C., it was dropped and hydrolyzed to obtain a suspension of silica fine particles. Further, the fine particles were fired at 250 ° C. to obtain silica fine powder 3. Various physical properties of the silica fine powder are as shown in Table 2.

<Example of production of silica fine powder 4>
A mixed gas having a volume ratio of argon and oxygen of 3: 1 is introduced into the reaction vessel to replace the atmosphere. Oxygen gas is supplied into this reaction vessel at 40 (m ³ / hr) and hydrogen gas at 20 (m ³ / hr), and an ignition device is used to form a combustion flame composed of oxygen-hydrogen. Next, the raw material hexamethyldisiloxane powder is charged into the combustion flame with a hydrogen carrier gas at a pressure of 4 kg / cm ³ to form a dust cloud. This dust cloud is ignited by a combustion flame and causes an oxidation reaction by dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled at a rate of 3 ° C./min to obtain silica powder 4. Various physical properties of the silica fine powder are as shown in Table 2.

<Production example of silica fine powder 5>
A fine silica powder 5 was obtained in the same manner as in Production Example 1 except that the carrier gas pressure was 1 kg / cm ³ in Production Example 1. Various physical properties of the silica fine powder are as shown in Table 2.

<Production example of silica fine powder 6>
Water (2.18 L), methanol (7 L) and 28% aqueous ammonia solution (1.0 kg) were added to a 30 L glass reactor equipped with a stirrer, a dripping port and a thermometer to prepare an ammonia mixture. The mixed solution was adjusted to 40 ° C. ± 0.5 ° C., and while stirring, a mixed solution of 912 g of tetramethoxysilane and 1.2 L of methanol was added dropwise while maintaining the temperature in the reaction vessel at 40 ° C. Hydrolysis was performed to obtain a suspension of silica fine particles. Further, the fine particles were fired at 250 ° C. to obtain silica fine powder 6. Various physical properties of the silica fine powder are as shown in Table 2.

<Production example of silica fine powder 7>
After adding 14 L of ethanol and 1.5 Kg of 28% aqueous ammonia solution to a 30 L glass reactor equipped with a stirrer, a dripping port, and a thermometer, ammonia gas was further blown to absorb 0.26 Kg and mixed to mix the ammonia mixture. Prepared. The mixed solution was adjusted to 10 ° C. ± 0.5 ° C. and stirred, so that a mixed solution of 1,130 g of tetraethoxysilane as a silane compound and 63 g of 3-aminopropyltriethoxysilane as a silane compound was adjusted to a temperature in the reaction vessel. While maintaining the temperature at 45 ° C., it was dropped and hydrolyzed to obtain a suspension of silica fine particles. Further, the fine particles were fired at 250 ° C. to obtain silica fine powder 7. Various physical properties of the silica fine powder are as shown in Table 2.

<Example of production of silica fine powder 8>
A silica fine powder 8 was obtained in the same manner as in Production Example 1 except that the carrier gas pressure was 15 kg / cm ³ in Production Example 1. Various physical properties of the silica fine powder are as shown in Table 2.

<Production example of silica fine powder 9>
Oxygen gas is supplied into the reaction vessel at 40 (m ³ / hr) and hydrogen gas at 20 (m ³ / hr) and ignited by an ignition device to form a combustion flame composed of an oxygen-hydrogen flame. The raw material trichlorosilane was supplied at 140 kg / hr to perform a flame hydrolysis reaction to obtain silica fine powder 9. Various physical properties of the silica fine powder are as shown in Table 2.

<Example of production of intermediate transfer belt>
An intermediate transfer belt having a composition as shown in Table 3 was produced.

  Raw material pellets mainly composed of resin and rubber shown in Table 3 were prepared. Each of these pellets is fed from an extruder to a multilayer annular die, laminated inside or outside the die and extruded. Cooling with a cooling mandrel inserted into the extruded multilayer cylindrical body to regulate the dimensions, obtain a semiconductive cylindrical body, cut this in a direction crossing the axial direction, and the multilayer structure An intermediate transfer belt was obtained. Table 3 shows the thickness, maximum displacement amount, plastic displacement amount, and elastic deformation rate of each layer.

<Production Example of Photoreceptor 1>
In the present invention, a cylindrical Al substrate having an outer diameter of 84 mm and a length of 358 mm is used, and the substrate temperature, gas type, gas flow, temperature in the reaction vessel, etc. are appropriately adjusted by high-frequency plasma CVD (PCVD) method. A system photoreceptor can be obtained.

  The following method is used for controlling the charging polarity of the photoreceptor. For example, a charge injection blocking layer composed of an a-Si: H film doped with phosphorus (P) in hydrogenated a-Si (a-Si: H), and light composed of an undoped a-Si: H film A negatively chargeable a-Si photoconductor can be obtained by providing an electrically conductive layer and an interface layer composed of an a-Si: H film doped with boron (B) on a conductive substrate. On the other hand, for example, a charge injection blocking layer composed of an a-Si: H film doped with boron (B), a photoconductive layer composed of an a-Si: H film doped with boron (B), silicon and carbon A positively chargeable a-Si photoconductor can be obtained by providing a surface protective layer composed of a silicon film (a-SiC: H) made of a conductive substrate on a conductive substrate.

  Based on the above manufacturing method, a positively chargeable photoreceptor 1 including a photoconductive layer containing amorphous silicon and a surface protective layer containing amorphous silicon carbide (a-SiC: H) on a cylindrical Al substrate was manufactured.

<Production Example of Photoreceptor 2>
On the basis of the above manufacturing method, a positive charge is provided with a photoconductive layer containing amorphous silicon on a cylindrical Al substrate and a surface protective layer containing amorphous carbon (aC: H) containing carbon atoms as a base and containing hydrogen atoms. Photoconductor 2 was produced.

<Example of production of photoconductor 3>
Based on the above manufacturing method, a positively chargeable photoreceptor 3 including a photoconductive layer containing amorphous silicon and a surface protective layer containing amorphous silicon nitride on a cylindrical Al base was manufactured.

[Example 1]
Binder resin 1 70 parts by mass Binder resin 2 30 parts by mass Magnetic iron oxide particles (average particle size 0.14 μm, Hc = 11.5 kA / m, σs = 90 Am ²
/ Kg, σr = 16 Am ² / kg) 70 parts by mass Fischer-Tropsch wax (melting point: 101 ° C.) 4 parts by mass charge control agent-3 2 parts by mass And kneaded.

The obtained kneaded product is cooled, coarsely pulverized with a hammer mill, then pulverized with a turbo mill, and the finely pulverized powder obtained is classified using a multi-division classifier utilizing the Coanda effect. 9 μm toner particles were obtained. Hydrophobic inorganic fine powder 1 (silica, BET140 m ² / g, hydrophobized with 30 parts of hexamethyldisilazane (HMDS) and 10 parts of dimethylsilicone oil) and silica with 100 parts by weight of toner particles and silica Toner 1 was obtained by externally mixing 0.2 parts by mass of fine powder 1 and 3.0 parts by mass of strontium titanate and sieving with a mesh having a mesh size of 150 μm. Table 4 shows the toner internal formulation and physical property values.

  For this toner 1, a commercially available copier (IRC-6870 made by Canon) was modified to 1.5 times the printing speed, the intermediate transfer belt was changed to 1, the photoconductor was changed to 1, and the penetration amount was 3%. Then, 1 million continuous printing tests were performed using a test chart with a printing ratio of 4% in an environment of 23 ° C. and 60% RH.

  The image density was measured with a Macbeth densitometer (manufactured by Macbeth) using an SPI filter to measure reflection density, and a 5 mm square image was measured. The fog is measured using a reflection densitometer (reflectometer model TC-6DS manufactured by Tokyo Denshoku Co., Ltd.). The worst value of the white background reflection density after image formation is Ds, and the reflection average density of the transfer material before image formation is Dr. The fog was evaluated using Ds-Dr as the fog amount. The smaller the number, the better the fog suppression. These evaluations were initially performed at 1 million sheets. The evaluation results are shown in Table 5.

  Further, at the end of the durability test, each of the items of transfer omission, scattering, roughness, and transferability was evaluated. The evaluation was performed according to the following indicators.

<Evaluation of splash>
At the end of durability evaluation, an isolated 1-dot pattern of 600 dpi was printed, and images were observed with an optical microscope to evaluate dot reproducibility.
A: There is no scattering from the toner from the latent image, and the dots are completely reproduced. B: There is a little protrusion (scattering) of the toner from the latent image. C: The toner protrudes (scatters) from the latent image. Many

<Evaluation of transfer omission>
At the end of the endurance test in each environment, the vertical and horizontal lines are both printed on 250 g / m ² (A4) paper on both sides of an 8 mm grid pattern with 200 μm, 500 μm, 1 mm, and 2 mm line width repeated. Arbitrary ten places of the 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 transferability>
The transferability was determined by developing and transferring the image after durability, and measuring the amount of toner before transfer on the photoreceptor (per unit area) and the amount of toner on the intermediate transfer body (per unit area). Further, another image was developed and transferred, and the amount of toner on the intermediate transfer member (per unit area) and the amount of toner on the transfer material (per unit area) were measured and obtained by the following equations.
Primary transfer efficiency (%) = {(toner amount on intermediate transfer member) / (toner amount before transfer on photoconductor)
)} × 100
Secondary transfer efficiency (%) = {(toner amount on transfer material) / (toner amount on intermediate transfer member)}
× 100

The evaluation method was judged based on the transfer efficiency after durability based on the following criteria.
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%)

<Evaluation of roughness of image in transfer>
After the endurance, an unfixed image at the time when the thin line image (7/1 mm) was transferred onto the transfer material was output, and an image was obtained by fixing it in an oven at 100 ° C. with no pressure. The resolution was observed and evaluated using a loupe. That is, the number of distinguishable lines was evaluated according to the following criteria. At this time, the number of lines that can be discriminated was an average value of 10 vertical lines and 10 horizontal lines.
A: 7 B: 5-6 C: 3-4 D: 2 or less

[Example 2, Reference Examples 3 and 4 , Examples 5 and 6, Reference Example 7, Example 8]
In the formulation shown in Table 4, the resin and charge control agent were changed in the same manner as in Example 1, and the toner No. 2-8 were produced. In Example 2 and Reference Example 7, hydrophobic inorganic fine powder 2 (silica, BET245 m ² / g, hydrophobized with 20 parts by mass of hexamethyldisilazane (HMDS)) was used. The physical property values thus obtained are shown in Table 4, and the results of the same test after remodeling to the intermediate transfer belt and the photoreceptor shown in Table 4 are shown in Table 5.

[Comparative Examples 1-8]
In the same manner as in Example 1, the developer No. 9-15 were produced. In Comparative Example 4, alumina (TM10, manufactured by Daimei Chemical Co., Ltd.) was used. The physical property values thus obtained are shown in Table 4, and the results of the same test after remodeling to the intermediate transfer belt and the photoreceptor shown in Table 4 are shown in Table 5.

1 is a schematic diagram illustrating an example of an image forming apparatus suitable for the present invention. It is explanatory drawing of the layer structure of a photoreceptor.

Explanation of symbols

1 Photosensitive member 4a, 4b Developing device 5 Intermediate transfer 15 Fixing device

Claims (2)

Charging the electrostatic image bearing member for bearing an electrostatic image to form an electrostatic image on the charged electrostatic charge image bearing member, forming a toner image by developing with toner an electrostatic charge image In the image forming method, the toner image on the electrostatic charge image carrier is transferred to a transfer material via an intermediate transfer member, and the toner image on the transfer material is fixed by a heat fixing unit.
Intermediate transfer member, the maximum displacement amount of the intermediate transfer member against the load 9.8 × 10 ^-5 N (Sb) is in the range of 0.10～1.00Myuemu, with respect to the load 9.8 × 10 ^-5 N An endless belt having an elastic deformation rate Eb (%) (Eb = (Sb−Ib) × 100 / Sb) of 50% or more, where Ib is a plastic displacement amount of the intermediate transfer member,
The amount of penetration i of the intermediate transfer member with respect to the surface of the electrostatic charge image carrier at the portion in contact with the electrostatic charge image carrier is 0% <i ≦ 5% of the diameter d of the electrostatic charge image carrier,
The toner has negatively chargeable magnetic toner particles containing at least a binder resin and magnetic iron oxide, a volume-based median diameter (D50) of 1.24 to 3.00 μm, and a specific surface area of 1.0 to 4.7 m. ² / g, a negatively chargeable magnetic toner obtained by externally adding a fine silica powder,
An image forming method, wherein a difference between a zeta potential of the silica fine powder and a zeta potential of the negatively chargeable toner particles at a pH of the aqueous dispersion of the negatively chargeable toner particles is 50 mV or less . Electrostatic charge image bearing member, to claim 1, characterized in that it comprises a surface protective layer comprising a photoconductive layer and an amorphous silicon and / or amorphous carbon containing at least amorphous silicon on a conductive substrate and conductive on a substrate The image forming method described.

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