Image formation methods

Abstract

This invention provides an image forming method that can suppress paper curling and localized deformation without using a humidifier when using a non-contact heating fixing method. [Solution] The image forming method of the present invention comprises the steps of: developing an electrostatic latent image formed on at least an electrophotographic photoreceptor with an electrostatic image developing toner; transferring the developed toner image to a transfer material; and fixing the transferred toner image. The fixing step fixes the toner image by non-contact heating, and the electrostatic image developing toner satisfies the following conditions (I) and (II). Condition (I): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the external additive contains silica particles A whose primary particle number average particle size is in the range of 55 to 400 nm. Condition (II): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the toner matrix particles contain metal particles or metal oxide particles.

Description

[Technical Field]

[0001] The present invention relates to an image forming method. In particular, the present invention relates to an image forming method that can suppress paper curling and local deformation when using a non-contact heating fixing method. [Background technology]

[0002] Conventionally, known fixing methods for electrostatic image developing toner include pressure fixing, which uses only a pressure roller at room temperature; contact heating fixing, which uses a heating roller or the like; and non-contact fixing methods. Hereafter, electrostatic image developing toner will also simply be referred to as "toner." Specific examples of non-contact fixing methods include flash fixing using xenon lamps, oven fixing using far-infrared rays, electromagnetic wave fixing using microwaves, and fixing methods using laser light or UV light. Among these, non-contact heating methods such as flash fixing and oven fixing are widely selected from the standpoint of reliability and stability.

[0003] For example, Patent Document 1 discloses an image forming method employing a non-contact heating fixing method. In the non-contact heating fixing method, the fixing member and the image surface are not in contact, so even when large-particle inorganic fine particles are used as an external additive, the fixing member is less likely to be damaged. Therefore, deterioration of image quality caused by damage to the fixing member can be suppressed during long-term use.

[0004] However, during the fixing process, the rapid evaporation of moisture from the heated surface can cause paper shrinkage, and curling can occur, especially in low-humidity environments. In particular, when using special color toners such as white toner, gold toner, and silver toner, these toners contain large amounts of metals or metal oxides with high thermal conductivity as pigments, so when heated during fixing, moisture evaporates rapidly from the areas where the special color toner is used. As a result, localized deformation of the paper can occur. As a technique to suppress such curling and paper deformation, a method of humidifying the image before fixing is known, as disclosed in Patent Document 1, for example. However, humidifying the images before fixing them resulted in larger equipment and decreased productivity. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 2934532 [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention has been made in view of the above-mentioned problems and circumstances. The problem to be solved by this invention is to provide an image forming method that can suppress paper curling and local deformation without using a humidifier when using a non-contact heating fixing method. [Means for solving the problem]

[0007] The inventors investigated the causes of the above problems in order to solve them. The inventors found that by including large-diameter silica particles with a number-average primary particle size of 55 to 400 nm as an external additive, it is possible to suppress paper curling and local deformation even when using a non-contact heat fixing method and when using toner containing metal particles or metal oxide particles. In other words, the above-mentioned problems according to the present invention are solved by the following means.

[0008] 1. An image forming method comprising the steps of: developing an electrostatic latent image formed on at least an electrophotographic photoreceptor with an electrostatic image developing toner; transferring the developed toner image to a transfer material; and fixing the transferred toner image, The fixing process involves fixing the toner image by non-contact heating, The electrostatic image developing toner satisfies the following conditions (I) and (II). Condition (I): At least one color of the toner for developing an electrostatic charge image has toner base particles and an external additive, and the external additive contains silica particles A having a number average particle diameter of primary particles within a range of 55 to 400 nm. Condition (II): At least one color of the toner for developing an electrostatic charge image has toner base particles and an external additive, and the toner base particles contain metal particles or metal oxide particles. An image forming method characterized by the above.

[0009] 2. The metal particles or metal oxide particles are aluminum particles, titanium oxide particles, or alumina particles. The image forming method according to claim 1, characterized by the above.

[0010] 3. The fixing step further fixes the toner image by applying pressure. The image forming method according to claim 1, characterized by the above.

[0011] 4. When the toner for developing an electrostatic charge image containing the silica particles A is left standing for 48 hours in an environment of a temperature of 10°C and a relative humidity of 20%, the moisture content is within a range of 0.05 to 0.90 mass%. The image forming method according to claim 1, characterized by the above.

[0012] 5. It has a step of applying a lubricant containing a fatty acid metal salt on the surface of the electrophotographic photoreceptor. The image forming method according to claim 1, characterized by the above.

[0013] 6. The external additive contained in at least one color of the toner for developing an electrostatic charge image contains a fatty acid metal salt. The image forming method according to claim 1, characterized by the above.

[0014] 7. The fatty acid metal salt contains any one of zinc stearate and calcium stearate. The image forming method according to claim 5 or 6, characterized by the above.

[0015] 8. The melting point of the fatty acid metal salt is 120°C or higher. The image forming method according to paragraph 5 or 6, characterized by the above.

[0016] 9. The mass ratio of the fatty acid metal salt to the silica particles A is within the range of 0.1 to 5.0. The image forming method according to paragraph 6, characterized in that

[0017] 10. The toner matrix particles contain a crystalline resin. The image forming method according to paragraph 1, characterized in that

[0018] 11. The external additive contains silica particles B having a primary particle number average particle size in the range of 20 to 40 nm. The image forming method according to paragraph 1, characterized in that

[0019] 12. The non-contact heating is heating by electromagnetic waves having a peak wavelength in the range of 1 to 10 μm. The image forming method according to paragraph 1, characterized in that

[0020] 13. The fixing process involves fixing the media on which the unfixed image has been formed while transporting it at a linear speed of 300-800 mm / s. The image forming method according to paragraph 1, characterized by the following:

[0021] 14. Print the image using the toner set. Of the toner sets mentioned above, the electrostatic image developing toners that satisfy condition (I) are four colors: yellow toner, magenta toner, cyan toner, and black toner. The electrostatic image developing toner that satisfies the above condition (II) is at least one of white toner, gold toner, and silver toner. The image forming method according to paragraph 1, characterized in that

[0022] 15. The electrostatic image developing toner that satisfies the above condition (I) further comprises pink toner or green toner. The image forming method according to paragraph 14, characterized by the following: [Effects of the Invention]

[0023] The above-described means of the present invention provides an image forming method that can suppress paper curling and local deformation without using a humidifier when using a non-contact heating fixing method. Although the mechanism of action or mechanism of the present invention is not yet clear, it is speculated as follows. The image forming method of the present invention contains silica particles A in which the external additive in at least one color of toner has a primary particle number average particle size in the range of 55 to 400 nm. The silica particles A, due to their large volume, contain a large amount of silanol groups internally. When water molecules adsorbed on these silanol groups are released, the image is humidified, thus suppressing curling and localized paper deformation caused by moisture evaporation, even in low-humidity environments. Here, if the particle size of the silica particles is less than 55 nm, they do not contain enough silanol groups, resulting in insufficient adsorption of water molecules and inadequate image humidification. Furthermore, when the particle size of the silica particles exceeds 400 nm, the silica particles become more easily detached from the toner matrix particles. As a result, these detached silica particles act as nuclei on the photoreceptor, causing strong adhesion between the silica particles and the toner matrix particles, making thorough cleaning impossible. Therefore, even when fixing using a non-contact heating method with toner containing metal particles or metal oxide particles with high thermal conductivity, using silica particles A as an external additive allows the image to be humidified by the abundant silanol groups contained in silica particles A, even without the use of a humidifier. As a result, it is presumed that curling due to moisture evaporation and localized paper deformation can be suppressed even by heating during fixing. [Brief explanation of the drawing]

[0024] [Figure 1] A schematic diagram showing an example of an image forming apparatus. [Figure 2] Schematic diagram showing an example of a fixing device. [Figure 3] Schematic diagram showing an example of an image forming unit. [Modes for carrying out the invention]

[0025] The present invention provides an image forming method comprising the steps of: developing an electrostatic latent image formed on at least an electrophotographic photoreceptor with an electrostatic image developing toner; transferring the developed toner image to a transfer material; and fixing the transferred toner image. The fixing process involves fixing the toner image by non-contact heating, The electrostatic image developing toner satisfies the following conditions (I) and (II). Condition (I): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the external additive contains silica particles A whose primary particle number average particle size is in the range of 55 to 400 nm. Condition (II): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the toner matrix particles contain metal particles or metal oxide particles. This feature is a technical feature common to or corresponding to each of the embodiments described below.

[0026] In embodiments of the present invention, it is preferable that the metal particles or metal oxide particles are aluminum particles, titanium oxide particles, or alumina particles. Including aluminum particles, titanium oxide particles, or alumina particles in the toner matrix particles results in a special color toner such as white toner, gold toner, or silver toner, which is preferable because it can enhance the design of printed materials.

[0027] The aforementioned fixing step is preferable in that the toner image is further fixed by applying pressure, as this ensures sufficient fixing strength.

[0028] Preferably, the moisture content of the electrostatic image developing toner containing the silica particles A is within the range of 0.05 to 0.90% by mass when left for 48 hours in an environment with a temperature of 10°C and a relative humidity of 20%. This humidifies the image and suppresses curling and localized paper deformation.

[0029] It is preferable to include a step of applying a lubricant containing a fatty acid metal salt to the surface of the electrophotographic photoreceptor. In solid image areas, moisture is difficult to remove during fixing, which can cause image lifting or tearing (blistering) in high-humidity environments. Therefore, by applying a fatty acid metal salt as a lubricant to the surface of the photoreceptor, the fatty acid metal salt migrates from the photoreceptor to the surface of the toner particles. This fatty acid metal salt partially suppresses the melting of toner particles during fixing. As a result, localized pores are formed in the toner layer, increasing the permeability of the toner image and suppressing blistering.

[0030] Preferably, the external additive in at least one color of the electrostatic image developing toner contains a fatty acid metal salt as a lubricant. By including fatty acid metal salts as an external additive, the presence of fatty acid metal salts between toner particles partially suppresses the melting of toner particles during fixing. As a result, localized pores are formed in the toner layer, increasing the permeability of the toner image and suppressing blistering.

[0031] It is preferable that the fatty acid metal salt contains either zinc stearate or calcium stearate. Zinc stearate and calcium stearate have a good balance of electrostatic affinity with large-diameter silica particles A, so the fatty acid metal salt is easily dispersed uniformly between toner particles. It is also known that wax can be used as an external additive instead of fatty acid metal salts as a lubricant, but since wax volatilizes due to the heat generated during fixing and can cause contamination inside the machine, non-volatile fatty acid metal salts are preferred.

[0032] It is preferable for the melting point of the fatty acid metal salt to be 120°C or higher in terms of suppressing uneven gloss. If the melting point of the fatty acid metal salt is lower than 120°C, it tends to melt during fixing, which can result in the toner image becoming partially high-gloss.

[0033] A mass ratio of the fatty acid metal salt to the silica particles A being within the range of 0.1 to 5.0 is preferable in that it can suppress both curling, local paper deformation, and blistering. It is also preferable in that the fatty acid metal salt is more easily distributed uniformly between the toner particles.

[0034] It is preferable that the toner matrix particles contain a crystalline resin, as this improves low-temperature fixing performance. Low-temperature fixing is effective in suppressing curling and paper deformation, as well as preventing blistering.

[0035] It is preferable that the external additive contains silica particles B having a primary particle number average size in the range of 20 to 40 nm. By using the silica particles B in combination, further humidification becomes possible without increasing the amount of large-diameter external additive that is easily detached from the toner.

[0036] The non-contact heating method is preferably one that uses electromagnetic waves with a peak wavelength of 1 to 10 μm, as this allows for obtaining sufficient fixing strength.

[0037] In the aforementioned fixing process, it is preferable to perform the fixing while transporting the media on which the unfixed image has been formed at a linear speed of 300 to 800 mm / s, as this allows for both sufficient fixing strength and productivity.

[0038] The image is output using a toner set, and it is preferable that the electrostatic image developing toners in the toner set that satisfy condition (I) are four colors: yellow toner, magenta toner, cyan toner, and black toner, and that the electrostatic image developing toners that satisfy condition (II) are at least one of white toner, gold toner, and silver toner. By using special color toners such as white toner, gold toner, and silver toner, the design quality of the printed material can be enhanced.

[0039] In addition to the electrostatic image developing toner that satisfies the above condition (I), it is preferable to further include pink toner or green toner, as this can enhance the design of the printed material.

[0040] The present invention, its components, and embodiments for carrying out the present invention will be described below. In this application, "~" is used to mean that the numerical values ​​written before and after it are included as the lower limit and upper limit.

[0041] [Summary of the image forming method of the present invention] The present invention provides an image forming method comprising the steps of: developing an electrostatic latent image formed on at least an electrophotographic photoreceptor with an electrostatic image developing toner; transferring the developed toner image to a transfer material; and fixing the transferred toner image, wherein the fixing step fixes the toner image by non-contact heating, and the electrostatic image developing toner satisfies the following conditions (I) and (II). Condition (I): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the external additive contains silica particles A whose primary particle number average particle size is in the range of 55 to 400 nm. Condition (II): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the toner matrix particles contain metal particles or metal oxide particles.

[0042] In this invention, at least one toner contains silica particles A as an external additive. Furthermore, the toner matrix particles in at least one color of toner contain metal particles or metal oxide particles. Here, "the toner matrix particles contain metal particles or metal oxide particles" means toner that contains metal particles or metal oxide particles, such as the special color toner described later.

[0043] A toner that satisfies condition (I) and a toner that satisfies condition (II) may be the same toner or different toners. That is, a toner containing silica particles A as an external additive and a toner containing metal particles or metal oxide particles may be the same toner or different toners. Specifically, for example, in the case of an image forming method using color toner and spot color toner, the external additive for the color toner may contain the silica particles A, and the external additive for the spot color toner may contain the silica particles A. Furthermore, both the external additives for the color toner and the spot color toner may contain the silica particles A. Furthermore, in the case of an image forming method using only spot color toner, the external additive for the spot color toner contains the silica particles A.

[0044] In the present invention, the toner is preferably selected from, for example, color toner or spot color toner. Color toner is a toner that contains the basic color of the colorants used. Specifically, color toners include yellow toner (Y) containing yellow colorants, magenta toner (M) containing magenta colorants, cyan toner (C) containing cyan colorants, and black toner (K) containing black colorants. Hereafter, yellow toner, magenta toner, cyan toner, and black toner will also be abbreviated simply as YMCK. The color toner may further contain other chromatic toners besides YMCK. Examples of such chromatic toners include red toner, orange toner, violet toner, pink toner, green toner, and the like. These color toners, by overlapping each toner, can form images with various color tones, enabling the creation of high-quality full-color images.

[0045] Special color toner is a toner that contains the aforementioned metal particles or metal oxide particles in its toner matrix particles. Specialty toners include, but are not limited to, white toner (W), gold toner, or silver toner.

[0046] Special color toners are used to enhance the added value of images. White toner, gold toner, and silver toner are particularly high-value toners. They can express colors that cannot be expressed with single-color toners, and by being present on or below color toners, they can enhance the color development and gloss of the color toners. In particular, when a transparent film is used as the recording medium (transfer material), forming an image with color toner on a white toner layer improves the visibility of the color toner and increases the added value of the image.

[0047] In the image forming method of the present invention, an image is output using a toner set, and it is preferable that the toners in the toner set that satisfy condition (I) are four colors: yellow toner, magenta toner, cyan toner, and black toner, and that the toner that satisfies condition (II) is at least one of white toner, gold toner, and silver toner. Furthermore, it is preferable to use pink toner or green toner in addition to the four toner colors mentioned above as a toner that satisfies condition (I).

[0048] <Number-average particle size of primary particles> The number-average particle size of the primary particles in the silica particle A is calculated as follows. Scanning electron microscope images of silica particles A are taken, and these images are binarized using an image analysis system such as the "LUZEX AP" image processing and analysis device (manufactured by Nireco Corporation). 100 particles are randomly selected, and their horizontal Ferret diameter is calculated. The average value of the horizontal Ferret diameters of the 100 particles is defined as the number-average primary particle size.

[0049] The number-average particle size of the primary particles in the silica particle A is within the range of 55 to 400 nm. By keeping the number-average particle size within this range, the particle size is relatively large, resulting in a large volume and abundant hydrophilic silanol groups within the silica particles. Therefore, the image is humidified when water molecules adsorbed on the silanol groups are released. As a result, curling and localized paper deformation due to moisture evaporation are suppressed even in low-humidity environments. The aforementioned number-average particle size is preferably in the range of 75 to 260 nm, and particularly preferably in the range of 100 to 180 nm, in that the silica particles have a sufficient number of silanol groups. When the average particle size is 400 nm or less, the particle size does not become too large, making it difficult for the particles to detach from the toner. Therefore, problems such as strong adhesion between the external additive and toner particles, centered around the external additive, which occurs when the particles detach from the toner on the photoreceptor, and thus prevents thorough cleaning, can be prevented.

[0050] From the viewpoint of ensuring transferability, the shape of the silica particles A is preferably such that the average circularity is 0.950 to 1.00. There are no restrictions on the method of producing such silica particles, but it is preferable that they be produced by the sol-gel method. In the gas phase method, silanol groups inside the silica particles tend to undergo dehydration condensation during the manufacturing process, but in the sol-gel method, dehydration condensation reactions are less likely to occur, so a rich amount of silanol groups remain inside the particles, which is preferable. The circularity of silica particle A can be measured as follows. Scanning electron microscope images of silica particles A are taken, and the obtained images are binarized using an image analysis system such as the "LUZEX AP" image processing and analysis device (manufactured by Nireco Corporation). At this time, particles that are not fully visible, such as those overlapping under other particles or at the edge of the field of view, are excluded. Then, 100 particles are randomly selected from those that are fully visible and measured. From the images obtained above, the circularity is calculated using the following formula. Circularity = (Perimeter of a circle with the same projection area as the particle image) / (Perimeter of the particle projection image) After calculating the circularity of 100 particles, the average circularity is calculated. The average circularity is the arithmetic mean obtained by adding up the circularity of each particle and dividing by the total number of particles measured. This average circularity is taken as the circularity of silica particle A.

[0051] To achieve the above-mentioned range for the number-average particle size of silica particles A, for example, adjustments can be made to the concentration of the alkoxysilane used as a raw material in the sol-gel method, the pH of the solvent, and the selection of the solvent. Furthermore, in order to bring the average circularity of silica particles A within the above range, for example, in the sol-gel method, methods such as controlling interparticle aggregation by adjusting the pH of the solvent can be used.

[0052] <Metal particles or metal oxide particles> The image forming method of the present invention includes a toner of at least one color, in which the toner matrix particles contain metal particles or metal oxide particles. The metal particles or metal oxide particles mentioned above vary depending on the special toner used. White toner contains titanium dioxide, etc., as metal particles or metal oxide particles. Gold toner contains aluminum, mica, alumina, etc., as metal particles or metal oxide particles. Silver toner contains aluminum, mica, alumina, etc., as metal particles or metal oxide particles. Further details will be described later.

[0053] <Fatty acid metal salts> The image forming method of the present invention preferably includes a step of applying a lubricant containing a fatty acid metal salt to the surface of an electrophotographic photoreceptor. Furthermore, in the image forming method of the present invention, it is preferable that at least one of the toner additives contains a fatty acid metal salt. That is, the fatty acid metal salt may be added as an additive or as a lubricant to the photoreceptor. Alternatively, the fatty acid metal salt may be used in combination as both an additive and a lubricant. The types of fatty acid metal salts will be described later. Furthermore, if a fatty acid metal salt is included as an external additive, it may be added as an external additive to the same toner as the one containing silica particles A, or as an external additive to the same toner as the one containing metal particles or metal oxide particles. In addition, a fatty acid metal salt may be included as an external additive to other toners.

[0054] The reasons why it is preferable to add fatty acid metal salts, at least as an external additive or lubricant, are as follows: In solid image areas, moisture is difficult to remove during fixing, which can cause image lifting or tearing (blistering) in high-humidity environments. Therefore, adding fatty acid metal salts as an external additive and / or lubricant partially suppresses the melting of toner particles due to the presence of fatty acid metal salts between them. As a result, localized pores are formed in the toner layer, increasing the permeability of the image area and suppressing blistering.

[0055] As for the fatty acid metal salt added as an external additive or lubricant, although details will be described later, zinc stearate or calcium stearate is preferred because it has a good balance of electrostatic affinity with the large-diameter silica particles A, and the fatty acid metal salt is easily dispersed uniformly between the toner particles. The melting point of the fatty acid metal salt added as an external additive or lubricant is preferably 120°C or higher. A melting point of 120°C or higher prevents uneven gloss due to partial high gloss. The melting point is more preferably in the range of 120 to 135°C. The melting point of fatty acid metal salts can be measured, for example, by a differential scanning calorimeter DSC7000X / PDC. The measurement procedure involves accurately weighing 0.80 mg to 1.20 mg of fatty acid metal salt to two decimal places, sealing it in an aluminum pan, and setting it in a holder. An empty aluminum pan is used as the reference. The measurement conditions are a measurement temperature of 0°C to 200°C and a heating rate of 10°C / min, with the melting point defined as the peak temperature of the endothermic peak.

[0056] <Toner moisture content> When toner is left in an environment with a temperature of 10°C and a relative humidity of 20% for 48 hours, the moisture content is preferably in the range of 0.05 to 0.90% by mass, and more preferably in the range of 0.08 to 0.75% by mass. Having the moisture content of the toner within this range helps to suppress curling and localized deformation of the paper.

[0057] The moisture content of the toner is measured using the AQ-300 trace moisture analyzer (manufactured by HIRANUMA Corporation) in the following manner. For the measurement sample, 1 g of toner (including external additives) was left at 10°C and 20% RH for 12 hours, and approximately 0.5 g was accurately weighed and defined as A (g). This sample was heated to 110°C to evaporate the adsorbed water, and titrated for 20 minutes using the moisture meter described above to determine the adsorbed water content B (μg) of the sample and the water content C (μg) of the reference sample. The water content of the sample is calculated from these values ​​using the following formula. Moisture content (mass%)=(BC)×100 / (A×1000000)

[0058] To keep the moisture content within the aforementioned range, for example, the large-diameter silica particles A may be included as an external additive.

[0059] The toner used in the present invention preferably contains toner matrix particles consisting of at least a binder resin and a colorant, and an external additive. In addition to the binder resin and colorant, the toner matrix particles may optionally contain various internal additives such as a mold release agent, a static charge control agent, or a surfactant. In this invention, "toner" refers to an aggregate of "toner particles," and "toner particles" refers to the toner matrix particles to which an external additive has been added. Furthermore, in the following description, when there is no need to distinguish between toner matrix particles and toner particles, they will simply be referred to as "toner particles" or "toner."

[0060] [Toner Configuration] (1) External additives <Silica Particle A> In the present invention, at least one toner contains silica particles A as an external additive, the number-average particle size of the primary particles being in the range of 55 to 400 nm. The content of silica particles A is preferably in the range of 0.10 to 3.50 parts by mass per 100 parts by mass of toner.

[0061] <Silica Particles B> The external additive preferably contains silica particles B, in addition to silica particles A, with a primary particle number average particle size in the range of 20 to 40 nm. Silica particles B may be added as an external additive to toner containing silica particles A, or as an external additive to toner containing metal particles or metal oxide particles, or as an external additive to both types of toners. Furthermore, it may be added as an external additive to other toners. The number-average particle size of the primary particles of silica particle B can be calculated in the same manner as the number-average particle size of silica particle A described above. By using silica particles A and silica particles B together as external additives, further humidification becomes possible without increasing the amount of large-diameter external additives that are easily detached from the toner. From the viewpoint of ensuring transferability, the shape of silica particle B is preferably such that the average circularity is 0.950 to 1.00. The circularity of silica particle B can be measured in the same manner as the circularity of silica particle A described above. The content of silica particles B is preferably in the range of 0.50 to 2.00 parts by mass per 100 parts by mass of toner.

[0062] Methods for producing silica particles A and silica particles B include known methods, namely dry methods such as combustion, arc, and melting, and wet methods such as sedimentation, gel, and sol-gel methods. Of these methods, the melting and sol-gel methods are preferred because they easily produce spherical silica particles. In particular, the sol-gel method is preferred due to its narrow particle size distribution. Therefore, by using such silica particles as raw materials for external additives, the electrostatic charge on the surface of the toner particles can be made uniform.

[0063] (Sol-gel method) Silica particles produced by the sol-gel method are created by the hydrolysis of hydrocarbyloxysilane compounds (such as alkoxysilane compounds and phenoxysilane compounds). One example of a method for producing silica particles by preparing them using the sol-gel method and then performing surface treatment is the following procedure. (i) Using aqueous ammonia as a catalyst, tetramethoxysilane or tetraethoxysilane is added dropwise to a mixed solvent of water and alcohol while heating and stirring to carry out the reaction. A silica sol suspension is formed in this manner. (ii) The silica sol suspension formed by the reaction is centrifuged to separate it into wet silica gel, alcohol, and aqueous ammonia. (iii) Add a solvent to the wet silica gel to return it to a silica sol state, and then add a hydrophobic treatment agent to perform a hydrophobic treatment on the surface of the silica core material. (iv) The solvent is removed from the hydrophobized silica sol, and the silica particles are dried and sieved to obtain the desired silica particles.

[0064] The average primary particle size of silica core materials produced by the sol-gel method can be adjusted to the desired particle size by controlling the amount of raw material compounds such as alkoxysilane, ammonia, alcohol, and water added during hydrolysis and polymerization, as well as the reaction temperature, stirring speed, and supply speed.

[0065] Silica particles A may be surface-treated with a hydrophobic treatment agent. As hydrophobic treatment agents, general silane coupling agents, titanate-based coupling agents, aluminate-based coupling agents, various silicone oils, silicone oils and fatty acids, and fatty acid metal salts can be used.

[0066] Examples of silane coupling agents include chlorosilanes, alkoxysilanes, silazanes, and special silylating agents. Specifically, these include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, and N,O-(bistrimethicone). Representative examples include lusilyl)acetamide, N,N-bis(trimethylsilyl)urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane.

[0067] Furthermore, it is also preferable to use silicone oil as a hydrophobic treatment agent. Specific examples of silicone oils include, for example, cyclic compounds such as organosiloxane oligomers, octamethylcyclotetrasiloxane, or decamethylcyclopentasiloxane, tetramethylcyclotetrasiloxane, and tetravinyltetramethylcyclotetrasiloxane, as well as linear or branched organosiloxanes. In addition, highly reactive silicone oils with modified groups introduced into the side chains, or one or both ends, or one or both ends of the side chains, or both ends of the side chains, may be used. Examples of modifying groups include alkoxy, carboxyl, carbinol, higher fatty acid modification, phenol, epoxy, methacrylic, and amino, but are not particularly limited. Furthermore, silicone oils having several modifying groups, such as amino / alkoxy modification, are also acceptable. Dimethyl silicone oil, these modified silicone oils, and other surface treatment agents may be mixed or used in combination. Examples of processing agents that can be used in combination include silane coupling agents, titanate coupling agents, aluminate coupling agents, various silicone oils, fatty acids, fatty acid metal salts, their esterified products, and rosinic acid.

[0068] Surface treatment methods include, for example, dry methods such as the spray-drying method, in which a treatment agent or a solution containing a treatment agent is sprayed onto particles suspended in the gas phase. Other surface treatment methods include wet methods, in which particles are immersed in a solution containing a treatment agent and dried, and mixed methods, in which the treatment agent and particles are mixed using a mixer.

[0069] (Method for measuring the degree of hydrophobicity) The degree of hydrophobicity can be determined using a powder wettability tester (WET-101P; manufactured by Resca Co., Ltd.) as follows. An example of measuring the degree of hydrophobicity of silica particles is described below.

[0070] Under laboratory conditions, a 20mm long stirrer tip and 60mL of ion-exchanged water at 25°C are placed in a 200mL tall beaker and set in a powder wettability tester (WET-101P; manufactured by Resca Co., Ltd.). 50mg of inorganic particles A are floated on top of the ion-exchanged water, and the lid and methanol supply nozzle are immediately attached. Measurement is started simultaneously with the start of stirrer mixing. The methanol supply rate (methanol special grade; manufactured by Kanto Chemical Co., Ltd.) is 2.0mL / min, and the measurement time is 70 minutes. The stirrer mixing speed is set to 380-420 rpm. The silica particles initially float at the interface of the deionized water, but as the methanol concentration increases, they gradually become wetted by the mixture of deionized water and methanol and disperse in the liquid. This causes the light transmittance of the liquid to gradually decrease. From the obtained data, the methanol concentration (vol%) calculated from the amount of methanol supplied (mL) is plotted on the x-axis, and the light transmittance (voltage ratio) (%) is plotted on the y-axis. The methanol concentration at which the light transmittance is midway between the maximum and minimum values ​​is defined as the "degree of hydrophobicity".

[0071] <Fatty acid metal salts as external additives> The aforementioned external additive preferably contains a fatty acid metal salt. The fatty acid metal salt may be added as an external additive to a toner containing silica particles A, or as an external additive to a toner containing metal particles or metal oxide particles, or as an external additive to both types of toners. Furthermore, it may be added as an external additive to other toners.

[0072] As the fatty acid metal salt, any known fatty acid metal salt can be used, but from the viewpoint of ductility, a fatty acid metal salt with a Mohs hardness of 2 or less is preferred. Furthermore, as mentioned above, the melting point of the fatty acid metal salt is preferably 120°C or higher. As such fatty acid metal salts, salts of metals selected from zinc, calcium, magnesium, aluminum, and lithium are preferred. Among these, zinc fatty acid, calcium fatty acid, lithium fatty acid, or magnesium fatty acid are more preferred, with zinc fatty acid being particularly preferred. Furthermore, higher fatty acids with 12 to 22 carbon atoms are preferred as the fatty acids in the fatty acid metal salt. Using fatty acids with 12 or more carbon atoms can suppress the generation of free fatty acids. If the number of carbon atoms in the fatty acid is 22 or less, the melting point of the fatty acid metal salt will not become too high, and good fixation properties can be obtained. Stearic acid is particularly preferred as the fatty acid. Preferred fatty acid metal salts used in this invention include zinc stearate (melting point: 122°C), calcium stearate (melting point: 149°C), and lithium stearate (melting point: 220°C). Zinc stearate or calcium stearate are more preferred. Zinc stearate or calcium stearate is preferred because it has a good balance of electrostatic affinity with large-diameter silica particles A, and the fatty acid metal salt is easily dispersed uniformly between the toner particles. Two or more of these fatty acid metal salts may be used in combination.

[0073] The number-average particle size of the fatty acid metal salt particles is preferably in the range of 0.80 to 15.0 μm, and more preferably in the range of 1.0 to 3.0 μm. The number-average particle size of the fatty acid metal salt particles can be calculated in the same manner as the number-average particle size of silica particles A described above.

[0074] When using a fatty acid metal salt as an external additive, the mass ratio of the fatty acid metal salt as an external additive to silica particles A (fatty acid metal salt / silica particles A) is preferably in the range of 0.1 to 5.0, and more preferably in the range of 0.2 to 4.0. The mass ratio is particularly preferably in the range of 0.25 to 2.5.

[0075] <Other external additives> As long as at least silica particles A are used as the external additive, known inorganic particles and organic particles can be used in addition to silica particles A, silica particles B, and fatty acid metal salt particles. One or more external additives may be used, and it is particularly preferable to use two or more external additives with different particle sizes. Different particle sizes result in different roles for external additives; generally, larger diameter particles exert a spacer effect, reducing the adhesion between toners, while smaller diameter particles can more easily coat the surface of the toner matrix, thereby improving fluidity. Regarding shape, not only spherical external additives but also needle-shaped ones, such as rutile-type titanium dioxide, as well as irregular shapes, spindle shapes, and konpeito-like shapes, can be used without restriction.

[0076] Examples of the inorganic particles include, for example, silica particles, hydrophobic silica particles (e.g., hydrophobic sol-gel silica particles, hydrophobic fumed silica particles, etc.), alumina particles, titanium oxide particles, hydrophobic titanium oxide (hydrophobic titania) particles, strontium titanate particles, zinc titanate particles and other inorganic titanate compound particles, zirconia particles, zinc oxide particles, chromium oxide particles, cerium oxide particles, antimony oxide particles, tungsten oxide particles, tin oxide particles, tellurium oxide particles, manganese oxide particles and boron oxide particles. The size of the inorganic particles is preferably 2 nm to 200 nm in average particle size, and more preferably 7 nm to 150 nm. The inorganic particles described above preferably have their surfaces hydrophobic, and known surface treatment agents are used for this hydrophobic treatment. The surface treatment agents may consist of one or more types and may include silane coupling agents, silicone oil, titanate coupling agents, aluminate coupling agents, fatty acids, fatty acid metal salts, their esterified products, and rosinic acid.

[0077] The aforementioned organic particles include spherical organic particles with a number-average primary particle diameter of approximately 10 to 2000 nm. Specifically, organic particles made from homopolymers such as styrene and methyl methacrylate, or copolymers thereof, can be used.

[0078] (2) Toner matrix particles Preferably, the toner matrix particles consist of toner matrix particles comprising at least a binder resin and a colorant, and external additives. In addition to the binder resin and colorant, the toner matrix particles may optionally contain various internal additives such as mold release agents, electrostatic control agents, or surfactants.

[0079] <Binding resin> The toner matrix particles preferably contain amorphous resin or crystalline resin, and are particularly preferably crystalline resin from the viewpoint of low-temperature fixation. Furthermore, the toner containing crystalline resin in the toner matrix particles may be a toner containing the silica particles A described above, a toner containing metal particles or metal oxide particles, or a toner containing both. The amorphous resin is more preferably a polyester resin or a vinyl resin.

[0080] In the present invention, it is preferable that the binder resin contains 50 to 90% by mass of amorphous resin and 5 to 30% by mass of crystalline resin relative to the total binder resin.

[0081] <Crystalline resin> In this invention, a crystalline resin refers to a resin that exhibits a clear endothermic peak rather than a stepwise endothermic change in differential scanning calorimetry (DSC). Specifically, a clear endothermic peak means a peak whose full width at half maximum (FWHM) is within 15°C when measured at a heating rate of 10°C / min in differential scanning calorimetry (DSC).

[0082] The melting point Tmc of the crystalline resin is preferably 60°C or higher from the viewpoint of obtaining sufficient high-temperature storage properties, and preferably 85°C or lower from the viewpoint of obtaining sufficient low-temperature fixing properties.

[0083] The melting point (Tmc) of crystalline resins can be measured using DSC. Specifically, a 0.5 mg sample of crystalline resin is sealed in an aluminum pan and placed in the sample holder of a differential scanning calorimeter (DSC7000X / PDC, manufactured by Hitachi High-Tech Corporation). The temperature is then increased from 0°C to 200°C at a heating rate of 10°C / min, and the temperature at the peak of the endothermic peak in the resulting endothermic curve is measured as the melting point (Tmc) of the crystalline resin.

[0084] In toner matrix particles, the content of crystalline resin relative to the binder resin is preferably in the range of 5 to 30% by mass, and more preferably in the range of 7 to 20% by mass, from the viewpoint of obtaining sufficient low-temperature fixation. When the content is 5% by mass or more, a sufficient plasticizing effect is obtained, and the low-temperature fixability is sufficient. Furthermore, when the content is 20% by mass or less, the thermal stability and physical stress stability of the toner are sufficient.

[0085] In toner matrix particles, the content of crystalline resin in the binder resin can be determined from the qualitative and quantitative results of the binder resin's constituent components. The types and amounts of constituent components can be identified, for example, by NMR measurement or pyrolysis GC-MS measurement.

[0086] For example, in the analysis of vinyl resin components, the constituent components are qualitatively determined from the detection time of each peak in the pyrogram obtained by pyrolysis GC-MS measurement and the MS spectrum. Furthermore, the constituent components can be quantified by creating a calibration curve for each peak. Alternatively, the resin may be dissolved using methyl ethyl ketone, chloroform, etc., and the resin components separated by GPC, and then analyzed using the above method.

[0087] Furthermore, when analyzing polyester resin components, it is effective to perform pretreatment using chemical decomposition such as alkaline hydrolysis and supercritical methanol decomposition.

[0088] The method of alkaline hydrolysis is as follows, for example. First, the toner and hydrolysis solution (alkaline agent, water, and organic solvent) are placed in a high-pressure wet decomposition crucible and heated in an oven at 80-150°C for 3 hours. The oven temperature and heating time may be adjusted depending on the composition of the sample. Examples of alkaline agents include sodium hydroxide and potassium hydroxide. Examples of organic solvents include methanol and DMSO (dimethyl sulfoxide). A small autoclave may be used as the container.

[0089] The molar ratios of each component can be calculated from the peaks derived from polyhydric alcohols in the proton nuclear magnetic resonance (1H-NMR) spectrum of the decomposition solution after toner hydrolysis. If the molar ratios of each component cannot be calculated from the 1H-NMR spectrum due to the influence of matrix components, the composition of polyhydric alcohols can also be analyzed from the GC chromatogram of the decomposition solution. The molar ratio of carboxylic acids can be similarly analyzed by derivatization treatment of the decomposition solution. Furthermore, the number and content (percentage) of carbon atoms in the constituent components (constituent units) of polyester can be determined not only by 1H-NMR measurement but also by pyrolysis gas chromatography (GC / MS: Gas Chromatography / Mass Spectrometry).

[0090] Furthermore, the content of vinyl resin and polyester resin in the binder resin can be calculated by dissolving the toner in the solvent in which the binder resin dissolves, performing solution NMR measurement, and determining the proportion of polyester resin and vinyl resin in the binder resin from the obtained spectrum. If crosslinking is involved, solid-state NMR can be used.

[0091] While not particularly limited, crystalline resins include vinyl resins such as styrene-acrylic resins and acrylic resins, polyolefin resins, polydiene resins, and polyester resins. Among these, crystalline polyester resins are preferred because they can provide sufficient low-temperature fixation and gloss uniformity, and are easy to use.

[0092] The number-average molecular weight (Mn) of the crystalline resin is preferably in the range of 2500 to 5000, and more preferably in the range of 3000 to 4500. Furthermore, the intensity of the fixed image is not insufficient, the crystalline resin is not pulverized during agitation of the developer, and the glass transition temperature (Tg) of the toner is not lowered due to excessive plasticizing effect, thus preventing a decrease in the thermal stability of the toner. In addition, sharp melt properties are exhibited, enabling low-temperature fixing.

[0093] The above Mn can be determined from the molecular weight distribution measured by gel permeation chromatography (GPC) as follows. The sample is added to tetrahydrofuran (THF) to a concentration of 1 mg / mL and mixed and dissolved at 25°C for 10 minutes. Then, the mixture is filtered through a 0.2 μm pore size membrane filter to prepare the sample solution. Using a GPC instrument HLC-8320GPC EcoSEC (Tosoh Corporation) and a column "TSKgelFOR HPLC" (Tosoh Corporation), THF was flowed at a rate of 0.35 mL / min as the carrier solvent while maintaining the column temperature at 40°C. 50 μL of the prepared sample solution was injected into the GPC instrument along with the carrier solvent, and the sample was detected using a differential refractive index detector (RI detector). The molecular weight distribution of the sample was then calculated using a calibration curve measured with 10 monodisperse polystyrene standard particles. In this case, if a peak caused by the filter was identified during data analysis, the region before that peak was set as the baseline.

[0094] Crystalline polyester resins are obtained by polycondensation reactions of divalent or higher carboxylic acids (polycarboxylic acids) and divalent or higher alcohols (polyalcohols). Examples of polycarboxylic acids include dicarboxylic acids. These dicarboxylic acids may be one or more types, preferably aliphatic dicarboxylic acids, and may further contain aromatic dicarboxylic acids. From the viewpoint of enhancing the crystallinity of the crystalline polyester, it is preferable that the aliphatic dicarboxylic acid be linear.

[0095] Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (dodecanediic acid), 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, their lower alkyl esters, and their acid anhydrides. Among these, aliphatic dicarboxylic acids having 6 to 16 carbon atoms are preferred from the viewpoint of easily achieving both low-temperature fixability and transferability, and aliphatic dicarboxylic acids having 10 to 14 carbon atoms are even more preferred.

[0096] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. Among these, terephthalic acid, isophthalic acid, or t-butylisophthalic acid are preferred from the viewpoint of availability and ease of emulsification.

[0097] In crystalline polyester resins, the content of aliphatic dicarboxylic acid-derived structural units relative to the dicarboxylic acid-derived structural units is preferably 50 mol% or more, from the viewpoint of ensuring sufficient crystallinity of the crystalline polyester. The content is more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 100 mol%.

[0098] Examples of polyhydric alcohol components include diols. The diol may be one or more types, preferably aliphatic diols, and may further contain other diols. From the viewpoint of enhancing the crystallinity of the crystalline polyester, the aliphatic diol is preferably linear.

[0099] Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,20-eicosanediol. Among these, aliphatic diols with 2 to 12 carbon atoms are preferred from the viewpoint of easily achieving both low-temperature fixability and transferability, and aliphatic diols with 4 to 10 carbon atoms are even more preferred. Other examples of diols include diols with double bonds and diols with sulfonic acid groups. Specifically, examples of diols with double bonds include 2-butene-1,4-diol, 3-hexene-1,6-diol, and 4-octen-1,8-diol.

[0100] In crystalline polyester resins, the content of aliphatic diol-derived structural units relative to diol-derived structural units is preferably 50 mol% or more, from the viewpoint of improving the low-temperature fixability of the toner and the glossiness of the final image formed. The content is more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 100 mol%.

[0101] The ratio of the diol to the dicarboxylic acid in the monomer of the crystalline polyester resin is preferably in the range of 2.0 / 1.0 to 1.0 / 2.0 in terms of the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the diol to the carboxyl group [COOH] of the dicarboxylic acid. The ratio is more preferably in the range of 1.5 / 1.0 to 1.0 / 1.5, and particularly preferably in the range of 1.3 / 1.0 to 1.0 / 1.3.

[0102] Crystalline polyester resins can be synthesized by polycondensation (esterification) of the above-mentioned polycarboxylic acids and polyhydric alcohols using known esterification catalysts.

[0103] The catalysts that can be used in the synthesis of crystalline polyester resins may be one or more. Examples of such catalysts include alkali metal compounds such as sodium and lithium; compounds containing group 2 elements such as magnesium and calcium; metal compounds such as aluminum, zinc, manganese, antimony, titanium, tin, zirconium, and germanium; phosphite compounds; phosphate compounds; and amine compounds.

[0104] Examples of tin compounds include dibutyltin oxide, tin octoate, tin dioctoate, and their salts. Examples of titanium compounds include titanium alkoxides such as tetran-butyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; and titanium chelates such as titanium tetraacetylacetonate, titanium lactate, and titanium triethanolamine. Examples of germanium compounds include germanium dioxide, while examples of aluminum compounds include oxides such as polyaluminum hydroxide, aluminum alkoxides, and tributylaluminate.

[0105] The polymerization temperature of the crystalline polyester resin is preferably in the range of 150 to 250°C. The polymerization time is preferably 0.5 to 10 hours. During polymerization, the reaction system may be subjected to reduced pressure as needed.

[0106] The crystalline resin according to the present invention may be one type or two or more types.

[0107] (Hybrid crystalline polyester resin) The crystalline polyester resin may be a hybrid crystalline polyester resin that includes an amorphous resin other than the crystalline polyester resin as a unit. Preferably, the amorphous resin unit is composed of the same type of resin as the amorphous resin contained in the binder resin, i.e., the resin other than the hybrid resin. By hybridizing in this manner, the affinity between the crystalline polyester resin and the binder resin is increased, and the hybrid resin is more easily incorporated into the amorphous resin.

[0108] "Same type of resin" means that characteristic chemical bonds are commonly contained within the repeating units. "Characteristic chemical bonds" follow the "polymer classification" described in the National Institute for Materials Science (NIMS) Materials Database (http: / / polymer.nims.go.jp / PoLyInfo / guide / jp / term polymer.html). Specifically, the chemical bonds constituting polymers classified into a total of 22 types—polyacrylic, polyamide, polyanhydride, polycarbonate, polydiene, polyester, polyhaloolefin, polyimide, polyimine, polyketone, polyolefin, polyether, polyphenylene, polyphosphazene, polysiloxane, polystyrene, polysulfide, polysulfone, polyurethane, polyurea, polyvinyl, and other polymers—are called "characteristic chemical bonds."

[0109] <Amorphous resin> The amorphous resin is a resin that does not possess the above-mentioned crystallinity. For example, an amorphous resin is a resin that, when differential scanning calorimetry (DSC) is performed on amorphous resin or toner particles, has no melting point and has a relatively high glass transition temperature (Tg).

[0110] The Tg of the above amorphous resin is preferably in the range of 30 to 80°C, and particularly preferably in the range of 45 to 65°C.

[0111] The glass transition temperature can be measured according to the method specified in ASTM (American Society for Testing and Materials) D3418-82 (DSC method). For measurement, instruments such as the DSC-7 differential scanning calorimeter (PerkinElmer), TAC7 / DX thermal analyzer controller (PerkinElmer), and DSC7000X / PDC differential scanning calorimeter (Hitachi High-Tech Corporation) can be used. Specifically, 3.0 mg of toner is sealed in an aluminum pan for measurement. An empty aluminum pan is used as a reference. Under the measurement conditions (heating and cooling conditions) which involve heating from 0°C to 200°C at a heating rate of 10°C / min and holding at 200°C isothermally for 1 minute, cooling from 200°C to 0°C at a cooling rate of 10°C / min and holding at 0°C isothermally for 1 minute, and heating from 0°C to 200°C at a heating rate of 10°C / min, the glass transition temperature can be determined from the DSC curve obtained during the second heating process from 0°C to 200°C.

[0112] The amorphous resin may be one or more types. Examples of amorphous resins include vinyl resins, urethane resins, urea resins, and amorphous polyester resins.

[0113] From the viewpoint of easily controlling thermoplasticity, amorphous resins preferably contain amorphous polyester resin or vinyl resin as the main component in the binder resin, and more preferably amorphous polyester resin as the main component. In this invention, the main component means that the binder resin contains 50% by mass or more of the resin.

[0114] (Amorphous polyester resin) Amorphous polyester resin is a polyester resin that, when differential scanning calorimetry (DSC) is performed, does not have a melting point and has a relatively high glass transition temperature (Tg). Since the monomers that make up amorphous polyester resins are different from the monomers that make up crystalline polyester resins, they can be distinguished from crystalline polyester resins by analysis such as NMR.

[0115] Amorphous polyester resins are obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polycarboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). There are no particular restrictions on the specific amorphous polyester resin, and conventionally known amorphous polyester resins in this art can be used.

[0116] The specific method for producing amorphous polyester resins is not particularly limited; the resin can be produced by polycondensing (esterifying) polycarboxylic acids and polyhydric alcohols using known esterification catalysts.

[0117] The catalyst that can be used during manufacturing, the temperature of polycondensation (esterification), and the time of polycondensation (esterification) are not particularly limited and are the same as those for the crystalline polyester resin described above.

[0118] The weight-average molecular weight (Mw) of the amorphous polyester resin is not particularly limited, but is preferably in the range of 5,000 to 100,000, and more preferably in the range of 5,000 to 50,000. If the weight-average molecular weight (Mw) is 5,000 or more, the heat-resistant storage properties of the toner can be improved. If the weight-average molecular weight is 100,000 or less, the low-temperature fixing properties can be further improved. The weight-average molecular weight (Mw) can be measured by the method described above.

[0119] Examples of polycarboxylic acids and polyhydric alcohols used in the preparation of amorphous polyester resins are not particularly limited, but include the following:

[0120] Polycarboxylic acids As the polycarboxylic acid, it is preferable to use unsaturated aliphatic polycarboxylic acids, aromatic polycarboxylic acids, and their derivatives. Saturated aliphatic polycarboxylic acids may also be used in combination if it is possible to form an amorphous resin.

[0121] Examples of unsaturated aliphatic polycarboxylic acids include unsaturated aliphatic dicarboxylic acids such as methylene succinic acid, fumaric acid, maleic acid, 3-hexene dioic acid, 3-octenedioic acid, and succinic acid substituted with alkenyl groups having 2 to 20 carbon atoms; unsaturated aliphatic tricarboxylic acids such as 3-butene-1,2,3-tricarboxylic acid, 4-pentene-1,2,4-tricarboxylic acid, and aconitic acid; and unsaturated aliphatic tetracarboxylic acids such as 4-pentene-1,2,3,4-tetracarboxylic acid. Lower alkyl esters and acid anhydrides of these can also be used.

[0122] Examples of aromatic polycarboxylic acids include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylenediacetic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and anthracenedicarboxylic acid; aromatic tricarboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid (trimesic acid), 1,2,4-naphthalentricarboxylic acid, and hemimellitic acid; aromatic tetracarboxylic acids such as pyromellitic acid and 1,2,3,4-butanetetracarboxylic acid; and aromatic hexacarboxylic acids such as melitic acid. Lower alkyl esters and acid anhydrides of these can also be used.

[0123] The above polycarboxylic acids may be used individually or as a mixture of two or more.

[0124] Polyhydric alcohols As for the polyhydric alcohol, it is preferable to use unsaturated aliphatic polyhydric alcohols, aromatic polyhydric alcohols, and their derivatives from the viewpoint of controlling compatibility with crystalline polyester resins. If an amorphous resin can be obtained, saturated aliphatic polyhydric alcohols may also be used in combination.

[0125] Examples of unsaturated aliphatic polyhydric alcohols include unsaturated aliphatic diols such as 2-butene-1,4-diol, 3-butene-1,4-diol, 2-butyne-1,4-diol, 3-butyne-1,4-diol, and 9-octadecene-7,12-diol. Derivatives of these can also be used.

[0126] Examples of aromatic polyhydric alcohols include bisphenols such as bisphenol A and bisphenol F, alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts, 1,3,5-benzenetriol, 1,2,4-benzenetriol, and 1,3,5-trihydroxymethylbenzene. Derivatives of these can also be used. Among these, bisphenol A compounds such as ethylene oxide adducts and propylene oxide adducts of bisphenol A are particularly preferred from the viewpoint of easily optimizing thermal properties.

[0127] Furthermore, while there are no particular restrictions on the number of carbon atoms in polyhydric alcohols with three or more valent values, it is preferable that the number of carbon atoms be within the range of 3 to 20, as this makes it easier to optimize the thermal properties.

[0128] The above polyhydric alcohols may be used individually or as a mixture of two or more.

[0129] The amorphous polyester resin may also be a hybrid amorphous polyester resin in which amorphous polyester polymerization segments and vinyl polymerization segments having styrene-derived structural units are chemically bonded together.

[0130] Furthermore, the constituent components and their proportions in each segment of the hybrid amorphous polyester resin can be determined, for example, by NMR measurement or methylation reaction Py-GC / MS measurement.

[0131] The amorphous polyester polymerization segment is a portion derived from a known polyester resin obtained by a polycondensation reaction with polycarboxylic acid and polyhydric alcohol components, similar to amorphous polyester resin, and refers to a polymerization segment in which no clear endothermic peak is observed in differential scanning calorimetry (DSC) of the toner.

[0132] Examples of polycarboxylic acid components include oxalic acid, succinic acid, maleic acid, adipic acid, 6-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucoic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, and p-carb Examples of polycarboxylic acids include xyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, diphenylacetic acid, diphenyl-p,p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracenedicarboxylic acid, and dodecenylsuccinic acid; trimellitic acid, pyromellitic acid, naphthalentricarboxylic acid, naphthalenetetracarboxylic acid, pyrentricarboxylic acid, and pyrenetetracarboxylic acid. These polycarboxylic acids can be used individually or in combination of two or more. Among these, it is preferable to use aliphatic unsaturated dicarboxylic acids such as fumaric acid, maleic acid, and mesaconic acid, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid, succinic acid, and trimellitic acid.

[0133] Examples of polyhydric alcohol components include dihydric alcohols such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct; and trihydric or higher polyols such as glycerin, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, and tetraethylolbenzoguanamine. These polyhydric alcohol components can be used individually or in mixtures of two or more. Among these, dihydric alcohols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct are preferred.

[0134] The vinyl polymerization segment is not particularly limited as long as it contains styrene-derived structural units, but considering the plasticity during thermal fixing, styrene-(meth)acrylic acid ester polymerization segments (styrene-acrylic polymerization segments) are preferred.

[0135] Styrene-acrylic polymerization segments are formed by addition polymerization of at least a styrene monomer and a (meth)acrylic acid ester monomer. Specific examples of monomers capable of forming styrene-acrylic polymerization segments are the same as those described for styrene-acrylic resins above, so their explanation is omitted here.

[0136] The content of styrene-derived structural units in the vinyl polymerization segment is preferably in the range of 40 to 95% by mass relative to the total amount of the vinyl polymerization segment. Furthermore, the content of structural units derived from (meth)acrylic acid ester monomers in the vinyl polymerization segment is preferably in the range of 5 to 60% by mass relative to the total amount of the vinyl polymerization segment.

[0137] Furthermore, it is preferable that the vinyl polymerization segment is formed by addition polymerization of compounds for chemical bonding to the amorphous polyester polymerization segment, in addition to the styrene monomer and (meth)acrylic acid ester monomer mentioned above. Specifically, it is preferable to use compounds that undergo ester bonding with hydroxyl groups [-OH] derived from polyhydric alcohol components or carboxyl groups [-COOH] derived from polyhydric carboxylic acid components, as contained in the above-mentioned crystalline polyester polymerization segment. Therefore, it is preferable that the vinyl polymerization segment is addition polymerizable to styrene and (meth)acrylic acid ester monomers and is further polymerized from compounds having carboxyl groups [-COOH] or hydroxyl groups [-OH].

[0138] Examples of such compounds include compounds having a carboxyl group, such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl maleic acid, and monoalkyl itaconic acid; and compounds having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate.

[0139] The content of constituent units derived from the above compound in the vinyl polymerization segment is preferably in the range of 0.5 to 20% by mass relative to the total amount of the vinyl polymerization segment.

[0140] The method for forming the styrene-acrylic polymerization segment is not particularly limited and includes methods of polymerizing monomers using known oil-soluble or water-soluble polymerization initiators. Specific examples of polymerization initiators are the same as those described in the section on hybrid crystalline polyester resins above.

[0141] The content of vinyl polymerization segments is preferably in the range of 2 to 25% by mass in the hybrid amorphous polyester resin.

[0142] Existing common schemes can be used to manufacture hybrid amorphous polyester resins. Three typical methods are as follows:

[0143] (1) A method for producing a hybrid amorphous polyester resin by pre-polymerizing vinyl polymerization segments and then carrying out a polymerization reaction in the presence of the vinyl polymerization segments to form amorphous polyester polymerization segments. (2) A method for producing a hybrid amorphous polyester resin by forming amorphous polyester polymerization segments and vinyl polymerization segments, and then bonding them together. (3) A method for producing a hybrid amorphous polyester resin by pre-polymerizing amorphous polyester polymer segments and carrying out a polymerization reaction to form vinyl polymer segments in the presence of the amorphous polyester polymer segments.

[0144] (Vinyl resin) Vinyl resins are polymers of vinyl compounds, such as acrylic acid ester resins, styrene-acrylic acid ester resins, and ethylene-vinyl acetate resins. Among these, styrene-acrylic acid ester resins (styrene-acrylic resins) are preferred from the viewpoint of plasticity during heat fixing.

[0145] Styrene-acrylic resins are formed by addition polymerization of at least a styrene monomer and a (meth)acrylic acid ester monomer. The styrene monomer includes not only styrene represented by the structural formula CH2=CH-C6H5, but also styrene derivatives having known side chains and functional groups in the styrene structure.

[0146] (Meth)acrylic acid monomers include not only acrylic acid esters and methacrylic acid esters represented by CH(R1)=CHCOOR2, but also acrylic acid ester derivatives and methacrylic acid ester derivatives that have known side chains or functional groups in the structure of these esters. R1 represents a hydrogen atom or a methyl group. R2 represents an alkyl group having 1 to 24 carbon atoms.

[0147] Examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, and pn-dodecylstyrene.

[0148] Examples of (meth)acrylic acid monomers include acrylic acid monomers such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate (2EHA), stearyl acrylate, lauryl acrylate, and phenyl acrylate; and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate.

[0149] In this specification, "(meth)acrylic acid monomer" is a general term encompassing "acrylic acid monomer" and "methacrylic acid monomer," and means either or both of them. For example, "(meth)acrylate" means either or both "methyl acrylate" and "methyl methacrylate."

[0150] The (meth)acrylic acid ester monomers mentioned above may be one or more. For example, it is possible to form a copolymer using a styrene monomer and two or more acrylic acid ester monomers, to form a copolymer using a styrene monomer and two or more methacrylic acid ester monomers, and to form a copolymer using a styrene monomer in combination with an acrylic acid ester monomer and a methacrylic acid ester monomer.

[0151] From the viewpoint of controlling the plasticity of the above-mentioned styrene-acrylic resin, the content of constituent units derived from styrene monomers in the above-mentioned styrene-acrylic resin is preferably in the range of 40 to 90% by mass. The content of constituent units derived from (meth)acrylic acid ester monomers in the amorphous resin is preferably in the range of 10 to 60% by mass.

[0152] The styrene-acrylic resin may further contain constituent units derived from monomers other than the styrene monomer and (meth)acrylic acid ester monomer described above. The other monomers are preferably compounds having a carboxyl group or a hydroxyl group.

[0153] The amorphous resin may further contain constituent units derived from monomers other than the styrene monomer and the (meth)acrylic acid ester monomer. The other monomer is preferably a compound that is esterified with a hydroxyl group (-OH) derived from a polyhydric alcohol or a carboxyl group (-COOH) derived from a polyhydric carboxylic acid. In other words, the amorphous resin is preferably a polymer that is addition polymerizable to the styrene monomer and the (meth)acrylic acid ester monomer, and is further polymerized with a compound having a carboxyl group or a hydroxyl group (an amphoteric compound).

[0154] Examples of the above compounds include compounds having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl maleic acid, monoalkyl itaconic acid, etc.; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate This includes compounds having a hydroxyl group, such as 4-hydroxybutyl (meth)acrylate and polyethylene glycol mono(meth)acrylate.

[0155] From the viewpoint of controlling toner charge amount, it is preferable that the content of the constituent units derived from the above amphoteric compound in the above styrene-acrylic resin is within the range of 0.5 to 20% by mass.

[0156] The above-mentioned styrene-acrylic resin can be synthesized by polymerizing monomers using known oil-soluble or water-soluble polymerization initiators. Examples of oil-soluble polymerization initiators include azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators.

[0157] Examples of azo or diazo polymerization initiators include 2,2′-azobis-(2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis(cyclohexane-1-carbonitride), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile.

[0158] Examples of peroxide-based polymerization initiators include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-(4,4-t-butylperoxycyclohexyl)propane, and tris-(t-butylperoxy)triazine.

[0159] When synthesizing styrene-acrylic resin particles by emulsion polymerization, water-soluble radical polymerization initiators can be used as polymerization initiators. Examples of water-soluble polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

[0160] The weight-average molecular weight (Mw) of the styrene-acrylic resin is preferably in the range of 5,000 to 150,000, and more preferably in the range of 10,000 to 70,000, from the viewpoint of easily controlling the plasticity of the amorphous resin.

[0161] <Coloring agent> The aforementioned colorants differ between spot color toners and color toners.

[0162] (Colorants for special color toners) The colorants used in spot color toners contain at least metal particles or metal oxide particles. Examples of white colorants used in white toner (W) include metal particles or metal oxide particles such as titanium dioxide, zinc oxide, and barium sulfate, which are surface-treated with alumina. The metal oxide particles are preferably contained in the toner matrix particles of the white toner in an amount of 2.0 to 60.0% by mass. In addition to the aforementioned metal oxide particles, other examples of white inorganic pigments include heavy calcium carbonate, light calcium carbonate, aluminum hydroxide, titanium white, talc, calcium sulfate, magnesium oxide, magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, and smexite. Examples of white organic pigments include polystyrene resin particles and urea-folimarin resin particles. Other examples of white pigments with a hollow structure include hollow resin particles and hollow silica. From the viewpoint of electrostatic properties and opacity, the white coloring agent (pigment) is preferably titanium dioxide. Any crystalline structure of titanium dioxide can be used, such as anatase, rutile, or brookite.

[0163] Examples of gold colorants (glossy colorants) used in gold toner include metal oxide particles such as alumina surface-treated with silica. Examples of gold colorants other than metal oxides include aluminum surface-treated with silica, brass powder, and mica surface-treated with titanium oxide. Furthermore, it is preferable that the gold colorant contains yellow colorants and red colorants described later, in addition to metal particles or metal oxide particles. The aforementioned metal particles or metal oxide particles are preferably contained in the toner matrix particles of the gold toner in an amount of 2.0 to 50.0% by mass.

[0164] Examples of silver colorants (glossy colorants) used in silver toner include metal oxide particles such as alumina surface-treated with titanium dioxide. Other silver colorants include aluminum and silver surface-treated with silica, and mica surface-treated with titanium dioxide. The aforementioned metal particles or metal oxide particles are preferably contained in the toner matrix particles of the silver toner in an amount of 2.0 to 50.0% by mass.

[0165] (Colorants for color toners) As black colorants used in black toner (K), various known substances can be arbitrarily used, such as carbon blacks including furnace black, channel black, acetylene black, thermal black, and lamp black, as well as magnetic powders such as magnetite and ferrite, dyes, and inorganic pigments containing non-magnetic iron oxide.

[0166] Examples of orange or yellow colorants used in yellow toner (Y) include CI Pigment Orange 31, CI Pigment Orange 43, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 17, CI Pigment Yellow 74, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 138, CI Pigment Yellow 155, CI Pigment Yellow 180, CI Pigment Yellow 185, and the like.

[0167] The following are colorants used for magenta or red in magenta toner (M): CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 5, CI Pigment Red 6, CI Pigment Red 7, CI Pigment Red 15, CI Pigment Red 16, CI Pigment Red 31, CI Pigment Red 48;1, CI Pigment Red 48;2, CI Pigment Red 48;3, CI Pigment Red 48;4, CI Pigment Red 53;1, CI Pigment Red 57;1, CI Pigment Red Examples include 84, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 139, CI Pigment Red 144, CI Pigment Red 149, CI Pigment Red 150, CI Pigment Red 166, CI Pigment Red 177, CI Pigment Red 178, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 202, CI Pigment Red 222, CI Pigment Red 238, CI Pigment Red 254, CI Pigment Red 269, and others.

[0168] Furthermore, examples of colorants for green or cyan used in cyan toner (C) include CI Pigment Blue 15, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 16, CI Pigment Blue 18:3, CI Pigment Blue 60, CI Pigment Blue 62, CI Pigment Blue 66, and CI Pigment Green 7.

[0169] For color toners other than the basic YMCK colors, for example, pigments used in orange toner include CI Pigment Orange 1, 11, and 38. For violet toner, pigments such as CI Pigment Violet 19, 23, and 29 are used. For pink toner, pigments such as CI Pigment Red 3, 81:4, 168, and 170 are used. For green toner, pigments such as CI Pigment Green 7 and 36 are used. For red toner, pigments such as CI Pigment Red 185, CI Pigment Orange 38, and CI Pigment Yellow 95 are used.

[0170] The colorants used in each color toner can be used individually or in combination of two or more types for each color. The average particle size (volume-based median diameter) of the colorant is preferably 10 to 1000 nm, and more preferably 30 to 300 nm. The volume-average particle size (volume-based median diameter) of the colorant can be measured using "UPA-150" (manufactured by Microtrac-Bell Co., Ltd.).

[0171] From the viewpoint of ensuring color reproduction accuracy of the image, the content of the coloring agent in the color toner matrix particles is preferably in the range of 1 to 30% by mass, and more preferably in the range of 2 to 20% by mass.

[0172] <Release agent> Any known release agent can be used. One or more release agents may be used. Examples of release agents include polyolefin waxes such as polyethylene wax and polypropylene wax; branched hydrocarbon waxes such as microcrystalline wax; long-chain hydrocarbon waxes such as paraffin wax and sazole wax; and dialkylketone waxes such as distearyl ketone; carnauba wax, montane wax, behenyl behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitate, distearyl maleate, and other ester waxes; as well as amide waxes such as ethylenediamine behenylamide and tristearyl trimellitate.

[0173] From the viewpoint of obtaining sufficient high-temperature storage, the melting point of the release agent is preferably 60°C or higher, and more preferably 65°C or higher. Furthermore, from the viewpoint of obtaining sufficient low-temperature fixing properties of the toner, the melting point of the release agent is preferably 100°C or lower, and more preferably 95°C or lower.

[0174] The release agent content is preferably in the range of 1 to 30% by mass relative to the toner matrix particles, and more preferably in the range of 5 to 20% by mass.

[0175] The toner according to the present invention may further contain other components besides the crystalline resin, amorphous resin, mold release agent, and colorant described above, to the extent that it achieves the effects of this embodiment. For example, an example of the other components that the toner matrix particles may contain is a charge control agent.

[0176] <Charge control agent> Known charge control agents can be used. Examples of charge control agents include nigrosine dyes, naphthenic acids or alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, and salicylic acid metal salts.

[0177] The charge control agent content in the toner is typically in the range of 0.1 to 10 parts by mass, preferably in the range of 0.5 to 5% by mass, per 100 parts by mass of the binder resin.

[0178] The particle size of the charge control agent is, for example, in the range of 10 to 1000 nm in number mean primary particle size, preferably in the range of 50 to 500 nm, and more preferably in the range of 80 to 300 nm.

[0179] [Toner manufacturing method] The toner manufacturing method is not particularly limited and includes known methods such as the kneading and grinding method, suspension polymerization method, emulsification and agglomeration method, dissolution and suspension method, polyester stretching method, and dispersion polymerization method.

[0180] <Method for manufacturing toner matrix particles> The following describes a method for manufacturing a special color toner containing metal particles or metal oxide particles in the toner matrix particles, using this as an example. Note that in the case of color toner, the same manufacturing method as for special color toner can be used, except that a coloring agent for color toners is used instead of metal particles or metal oxide particles as the coloring agent. The toner matrix particles of the special color toner preferably contain a binder resin, a release agent, a crystalline resin, metal particles or metal oxide particles, and optionally other colorants and internal additives. The manufacturing method is not particularly limited, but the emulsification and agglutination method is preferred. The emulsification and agglutination method makes it possible to obtain toner matrix particles with a sharp particle size distribution and highly controlled particle size. An example of a method for producing toner particles by the emulsification and agglutination method is shown below. (1) A step of preparing a dispersion in which metal particles or metal oxide particles are dispersed as coloring agent particles in an aqueous medium. (2) A step of preparing a dispersion in which binding resin particles containing an internal additive as needed are dispersed in an aqueous medium. (3) A process of mixing a dispersion of colorant particles and a dispersion of binder resin particles to form toner particles by agglomerating, assembling, and fusing the colorant particles and binder resin particles. (4) A process to filter out toner particles from the toner particle dispersion system (aqueous medium) and remove surfactants, etc. (5) Process to dry the toner particles (6) Step of adding an external additive to the toner particles

[0181] (Flocculant) The aforementioned flocculant is not particularly limited, but one selected from metal salts is preferably used. Examples include monovalent metal salts such as alkali metal salts like sodium, potassium, and lithium; divalent metal salts such as calcium, magnesium, manganese, and copper; and trivalent metal salts such as iron and aluminum. Specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Among these, divalent metal salts are particularly preferred. Using divalent metal salts allows flocculation to proceed with a smaller amount. These may be used individually or in combination of two or more.

[0182] (Particle size of toner matrix particles) The volume-average particle size of the toner matrix is ​​preferably in the range of 5.0 to 15.0 μm for spot color toners and 4.5 to 8 μm for color toners. From the viewpoint of improving image quality, a smaller diameter is preferable, but if the particle size is too small, the adhesion force of the toner matrix particles increases, and cleaning performance deteriorates. If the volume-average particle size of the toner matrix is ​​within the above range, it is possible to satisfy both the viewpoints of output image quality and cleaning performance, while also achieving compatibility with functions such as charging, developing, and transfer.

[0183] The volume-average particle size of the toner can be measured and calculated as the volume-based median diameter (D50% diameter) using, for example, a device consisting of a "Multisizer 3 (Beckman Coulter)" connected to a computer system (Beckman Coulter) equipped with data processing software "Software V3.51," in the same manner as described above. The measurement procedure involves dispersing 0.02 g of toner particles in 20 ml of surfactant solution, allowing it to disperse, and then performing ultrasonic dispersion for 1 minute to prepare a toner particle dispersion. For the surfactant solution, for example, a neutral detergent containing surfactant components diluted 10 times with pure water is suitable. This toner particle dispersion is then added dropwise to an ISOTON II (Beckman Coulter) beaker until the measurement concentration reaches 5-10%, and the measurement is performed with the instrument count set to 25,000 particles. Here, a Multisizer 3 with an aperture diameter of 100 μm is used. The measurement involves calculating the frequency number by dividing the 2-60 μm range into 256 sections, and the particle diameter representing the smallest volume integrated fraction (50%) is obtained as the volume-based median diameter (D50% diameter), which is then used as the toner volume-average particle size.

[0184] (Average circularity of toner matrix particles) The average circularity of the toner matrix particles is preferably in the range of 0.920 to 0.970 for spot color toners, and more preferably in the range of 0.940 to 0.985 for color toners. Here, the measurement of the average circularity is as described above.

[0185] (Core-shell structure) The emulsification agglutination method for producing toner particles is suitable for producing toner particles having a core-shell structure, and it is more preferable that the toner matrix particles have a core-shell structure. An example of manufacturing toner matrix particles having a core-shell structure is as follows: First, binder resin particles and colorant particles for the core particles are aggregated, associated, and fused together to create core particles. Next, binder resin particles for the shell layer are added to the dispersion of core particles. This aggregates and fuses the binder resin particles for the shell layer onto the surface of the core particles, forming a shell layer that covers the surface of the core particles.

[0186] (External processing) In the step of adding an external additive to the toner particles as described in (6) above, a mechanical mixing device can be used for the mixing of the external additive with the toner matrix particles. Mechanical mixing devices such as Henschel mixers, Nauter mixers, and Turbuler mixers can be used. Among these, a mixing device that can apply shear force to the particles being processed, such as a Henschel mixer, can be used, and the mixing process can be performed by increasing the mixing time or increasing the rotational speed of the stirring blades. Furthermore, when using multiple types of external additives, all external additives may be mixed with the toner matrix particles at once, or they may be mixed in multiple stages depending on the type of external additive.

[0187] The method for mixing external additives allows for control over the degree of disintegration and adhesion strength of the external additives by controlling the mixing intensity, i.e., the peripheral speed of the stirring blades, mixing time, or mixing temperature, using the mechanical mixing device described above.

[0188] As an external additive, silica particles A, silica particles B, or fatty acid metal salts can be used, as described above.

[0189] [Developer] The toner according to the present invention can be used as a magnetic or non-magnetic one-component developer, or it may be mixed with a carrier and used as a two-component developer.

[0190] <Two-component developer> A two-component developer can be constructed by appropriately mixing toner particles and carrier particles so that the toner particle content (toner concentration) is 4.0 to 15.0% by mass. Examples of mixing equipment used for this mixing include Nauter mixers, W-cone mixers, and V-type mixers.

[0191] <Carrier particles> The carrier particles are composed of magnetic materials. Examples of carrier particles include coated carrier particles having a core material particle made of a magnetic material and a coating layer covering its surface, and resin-dispersed carrier particles in which fine magnetic powder is dispersed in a resin. From the viewpoint of suppressing the adhesion of carrier particles to the photoreceptor, it is preferable that the carrier particles be coated carrier particles.

[0192] (Carrier core (core material particles)) The core material particles are composed of magnetic materials, such as substances that are strongly magnetized in a particular direction by a magnetic field. The magnetic materials may be one type or more. Examples of magnetic materials include ferromagnetic metals such as iron, nickel, and cobalt, alloys or compounds containing these metals, and alloys that exhibit ferromagnetism upon heat treatment.

[0193] Examples of metals exhibiting ferromagnetism or compounds containing them include iron, ferrite represented by formula (a) below, and magnetite represented by formula (b) below. In formulas (a) and (b), M represents one or more monovalent or divalent metals selected from the group consisting of Mn, Fe, Ni, Co, Cu, Mg, Zn, Cd, and Li. Formula (a): MO·Fe2O3 Formula (b): MFe2O4

[0194] Furthermore, examples of alloys that exhibit ferromagnetism after the above heat treatment include Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin, as well as chromium dioxide.

[0195] The core material particles are preferably various types of ferrite. This is because the specific gravity of the coated carrier particles is lower than the specific gravity of the metal constituting the core material particles, which reduces the agitation impact force within the developer.

[0196] (Carrier coating resin (coating material)) The coating material can be a known resin used for coating the core material particles of carrier particles. The coating material is preferably a resin having a cycloalkyl group, from the viewpoint of reducing the moisture adsorption of the carrier particles and from the viewpoint of improving the adhesion between the coating layer and the core material particles. Examples of cycloalkyl groups include cyclohexyl, cyclopentyl, cyclopropyl, cyclobutyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl groups. Among these, cyclohexyl or cyclopentyl groups are preferred, and cyclohexyl groups are more preferred from the viewpoint of adhesion between the coating layer and the ferrite particles. The weight-average molecular weight Mw of the resin is, for example, 10,000 to 800,000, and more preferably 100,000 to 750,000. The content of the resin having the cycloalkyl group in the resin is, for example, 10 to 90% by mass. The content of the resin having the cycloalkyl group in the resin can be determined, for example, by performing thermal decomposition GC-MS measurement, qualitative analysis of the constituent components from the detection time of each peak in the obtained pyrogram and the MS spectrum, and further quantification by creating a calibration curve for each peak. Alternatively, the resin may be dissolved using methyl ethyl ketone, chloroform, etc., and the resin components may be separated by GPC and analyzed by the above method.

[0197] The following describes an image forming apparatus for electrophotography used in the image forming method of the present invention. Figure 1 is a schematic diagram showing an example of an image forming apparatus. Figure 2 is a schematic diagram showing an example of a fixing apparatus. The image forming method of the present invention forms an image on a transfer material using a toner that satisfies the above-described conditions (I) and (II). The transfer material is also called a recording medium or substrate, and examples include paper. Specifically, the process includes at least a charging step, an exposure step, a developing step, a transfer step, and a fixing step. Preferably, the transfer step includes a primary transfer step in which a toner image is transferred from an electrostatic image carrier (photoreceptor drum 4) onto an intermediate transfer body (intermediate transfer belt 6), and a secondary transfer step in which the toner image on the intermediate transfer body is transferred onto a transfer material (paper S). The fixing process includes a step of fixing the toner image by non-contact heating. Preferably, the fixing process also includes a step of further fixing the toner image by pressurization after fixing by non-contact heating. Furthermore, in the image forming method of the present invention, an image is output using a toner set, and it is preferable that the toners satisfying condition (I) in the toner set are four colors: yellow toner, magenta toner, cyan toner, and black toner, and that the toner satisfying condition (II) is at least one of the spot color toners such as white toner, gold toner, and silver toner. Furthermore, it is preferable to use pink toner or green toner in addition to the four toner colors mentioned above as a toner that satisfies condition (I).

[0198] The image forming apparatus used in the present invention comprises at least an electrophotographic photoreceptor, a charging means, an exposure means, a developing means, a transfer means, a fixing means, and a cleaning means. The electrophotographic photoreceptor is a photoreceptor drum. The charging means is a charging device that charges the surface of the electrophotographic photoreceptor. The exposure means is an exposure device that forms an electrostatic charge image on the surface of the photoreceptor drum. The developing means is a developing device that develops the electrostatic charge image with a developer containing toner to form a toner image. The transfer means is a transfer device that transfers the developing means and the toner image to a transfer material. The fixing means is a fixing device that fixes the toner image transferred to the transfer material. The cleaning means is a cleaning device that removes residual toner from the electrophotographic photoreceptor.

[0199] Specifically, the image forming apparatus 1 shown in Figure 1 has image forming units 51T, 52T, 5Y, 5M, 5C, and 5K that form images using toners of the following colors: T1 (spot color 1), T2 (spot color 2), Y (yellow), M (magenta), C (cyan), and K (black). Each image forming unit 51T, 52T, 5Y, 5M, 5C, and 5K is equipped with a photoreceptor drum 41T, 42T, 4Y, 4M, 4C, and 4K, respectively. Since these all have the same configuration except for the toner they contain, the symbols representing the colors may be omitted from now on. In the configuration shown in Figure 1, the output toner image has K as the bottom layer, followed by C, M, and Y, with the top layer being a spot color. However, in this invention, there are no particular restrictions on the combination or order of the toner colors used. For example, the spot color toner may be the bottom layer of the image, or the bottom and top layers may each be spot colors. The image forming apparatus 1 further includes an intermediate transfer section equipped with an intermediate transfer belt 6 and a secondary transfer section equipped with a secondary transfer roller 7. The image forming apparatus 1 also includes an operation display section 105, a paper feeder 20, and a paper storage section 14. The paper feeder 20 is equipped with multiple paper storage compartments 20a depending on the size and type of paper. Based on instructions from the image forming apparatus 1, the paper feeder 20 selects the appropriate paper storage compartment 20a, and the paper S is removed by a paper feeder (not shown) and sent to the transport path C of the image forming apparatus 1. Also, if the operation display unit 105 selects paper storage compartment 14, the paper stored in paper storage compartment 14 is sent to the transport path C. In Figure 1, reference numerals 11, 12, and 13 indicate paper transport rollers.

[0200] Figure 3 is a schematic diagram showing an example of an image forming unit. The image forming unit 5 includes an exposure device (not shown), a developing device 412, a photoreceptor drum 4, a charging device 414, and a drum cleaning device 415.

[0201] The photoreceptor drum 4 is, for example, a negatively charged organic photoreceptor. The surface of the photoreceptor drum 4 is photoconductive. The photoreceptor drum 4 corresponds to the photoreceptor.

[0202] The charging device 414 is preferably a charging roller type that charges the surface of the photoreceptor drum 4 using charging rollers provided to contact the photoreceptor drum 4. The charging device 414 may also be a contact charging device that charges the photoreceptor drum 4 by bringing contact charging members such as a corona charger, charging brush, or charging blade into contact with the photoreceptor drum 4.

[0203] The exposure apparatus includes, for example, a semiconductor laser as a light source and a light deflection device (polygon motor) that directs laser light corresponding to the image to be formed toward the photoreceptor drum 4.

[0204] The developing apparatus 412 is a developing apparatus that uses a two-component developing method. The developing apparatus 412 includes, for example, a developing container, developing rollers (magnetic rollers), a partition wall, a transport roller, and an agitation roller. The developing container holds toner as a two-component developer. The developing roller is rotatably positioned at the opening of the developing container. A partition wall divides the inside of the developing container, allowing the two-component developer to communicate with each other. A transport roller conveys the two-component developer from the opening side of the developing container toward the developing roller. A stirring roller agitates the two-component developer inside the developing container.

[0205] The intermediate transfer section includes an intermediate transfer belt 6 as shown in Figure 1, a primary transfer roller (not shown) that presses the intermediate transfer belt 6 against the photoreceptor drum 4, a plurality of support rollers (not shown) including a backup roller (not shown), and a belt cleaning device (not shown). The intermediate transfer belt 6 is stretched in a loop around multiple support rollers (not shown). The intermediate transfer belt 6 travels at a constant speed as at least one of the drive rollers among the multiple support rollers rotates. The secondary transfer section has a secondary transfer roller 7.

[0206] As shown in Figure 2, the fixing device has a non-contact heating fixing section 160. Furthermore, it is preferable that the fixing device also has a pressure fixing section 170 in addition to the non-contact heating fixing section 160. The non-contact heating and fixing unit 160 includes a non-contact heating heater 161, an insulating cover 162, and a paper transport means. The non-contact heating element 161 heats the image surface of the paper without contact. The heat insulating cover 162 covers the non-contact heating element 161 except for the image surface side. The paper transport means is positioned vertically below the paper path of the non-contact heating element 161. The non-contact heating element 161 is located inside the heat insulating cover 162, and its surface temperature is controlled to a desired temperature by a control means (not shown).

[0207] The non-contact heating element 161 is preferably heated by electromagnetic waves having a peak wavelength of 1 to 10 μm. Considering the differences in light absorption between the spot color, black, yellow, magenta, and cyan toners, as well as in the non-image areas, the non-contact heating element 161 should preferably have a longer wavelength, and further considering the balance with energy density, a far-infrared heater is preferable. Examples of far-infrared heaters include ceramic heaters and halogen heaters. A reflector 163 for concentrating light is installed on the top of the non-contact heating element 161 to increase heating efficiency. The reflector 163 may be made of aluminum processed to a mirror surface.

[0208] For the insulating cover 162 used to maintain a high temperature around the non-contact heating element 161, a material with high thermal insulation and heat resistance, such as ceramic fiber, can be used.

[0209] The paper transport means preferably transports the paper on which the unfixed image has been formed at a linear speed of 300 to 800 mm / s while fixing it in the non-contact heating fixing unit 160 and the pressure fixing unit 170. The linear speed is more preferably within the range of 350 to 750 mm / s. In this embodiment, a suction belt 165 is used as the paper transport means. The suction belt 165 is positioned vertically below the paper path as viewed from the non-contact heating heater 161. The suction belt 165 is made of a highly heat-resistant rubber material such as silicone rubber and has suction holes, and is wrapped around a drive roller 166 and a driven roller 167. The drive roller 166 is rotated at a predetermined peripheral speed by a drive mechanism (not shown).

[0210] The drive roller 166 and the driven roller 167 can be made of metal such as aluminum, and their relative positions in relation to the paper transport direction may be reversed. A suction fan 168 is positioned inside the suction belt 165 to suck in the transported paper. The inside of the suction belt 165 is the space between the drive roller 166 and the driven roller 167.

[0211] In the non-contact heating unit 160, the toner image and the paper are heated mainly by radiation from the non-contact heater 161. Therefore, the melting of the toner is promoted and a fixed image is obtained. After passing through the non-contact heating unit 160, the toner image on the paper S reaches the pressure fixing unit 170.

[0212] In the pressure fixing unit 170, the fixing roller 172 and the pressure roller 171 are arranged in parallel vertically, and both ends of each are rotatably supported by bearing members (not shown). Further, by a pressure mechanism (not shown) using a spring or the like, the pressure roller 171 is biased in the rotational axis direction of the fixing roller 172 and is pressed against the lower surface portion of the fixing roller 172 with a predetermined pressure to form a pressure nip portion. <​​​​​​​​​​​​​​​​​​​This further promotes toner melting and smooths the surface. The feeding of paper through the non-contact heating section 160 and the pressurized fixing section 170 ensures fixing quality.

[0216] (Lubricant application mechanism) The image forming apparatus 1 preferably includes a lubricant application mechanism. As shown in Figure 3, the lubricant coating mechanism is preferably mounted upstream or downstream of the cleaning blade 415a for the purpose of reducing the frictional force between the photoreceptor drum 4 and the cleaning blade 415a. The coating mechanism is also referred to as the lubricant coating unit 416.

[0217] The lubricant application unit 416 is not particularly limited as long as it has a mechanism capable of applying lubricant. For example, the lubricant application unit 416 may be a mechanism that supplies lubricant onto the photoreceptor drum 4 via a brush from a lubricant rod made by solidifying lubricant, and applies the lubricant with a fixed blade separate from the cleaning blade 415a.

[0218] One type of lubricant is a fatty acid metal salt. Since fatty acid metal salts are the same as those contained in the external additives mentioned above, their description is omitted here. Although it is known that wax can be used as a lubricant instead of fatty acid metal salts, wax volatilizes due to the heat generated during setting, causing contamination inside the machine. Therefore, non-volatile fatty acid metal salts are preferred.

[0219] An example of an image formation method using the image forming apparatus 1 will be described. First, the input image data undergoes predetermined image processing in the image processing unit (not shown) and is then sent to the exposure device.

[0220] The photoreceptor drum 4 rotates at a constant peripheral speed. Lubricant is supplied onto the photoreceptor drum 4 from the lubricant application unit 416. The charging device 414 uniformly charges the surface of the photoreceptor drum 4 with negative polarity. In the exposure apparatus (not shown), the polygon mirror of the polygon motor rotates at high speed, and laser light corresponding to the input image data for each color component is unfolded along the axis of the photoreceptor drum 4 and irradiated onto the outer surface of the photoreceptor drum 4 along that axis. In this way, an electrostatic image is formed on the surface of the photoreceptor drum 4.

[0221] In the developing device 412, toner particles become charged by agitation and transport of the two-component developer in the developing container. The two-component developer is then transported to the developing roller, where a magnetic brush is formed on the surface of the developing roller. The charged toner particles electrostatically adhere from the magnetic brush to the portion of the photoreceptor drum 4 corresponding to the electrostatic charge image. In this way, the electrostatic charge image on the surface of the photoreceptor drum 4 is visualized, and a toner image corresponding to the electrostatic charge image is formed on the surface of the photoreceptor drum 4.

[0222] The toner image on the surface of the photoreceptor drum 4 is transferred to the intermediate transfer belt 6. Any remaining toner on the surface of the photoreceptor drum 4 after the transfer is removed by a drum cleaning device having a cleaning blade 415a that slides against the surface of the photoreceptor drum 4.

[0223] The primary transfer roller presses the intermediate transfer belt 6 against the photoreceptor drum 4, thereby forming a primary transfer nip for each photoreceptor drum between the photoreceptor drum 4 and the intermediate transfer belt 6. In this primary transfer nip, the toner images of each color are sequentially transferred onto the intermediate transfer belt 6.

[0224] Next, when the paper S is transported to the secondary transfer nip, a transfer bias is applied to the secondary transfer roller 7. This application of the transfer bias transfers the toner image supported on the intermediate transfer belt 6 to the paper S. The paper S, with the transferred toner image, is then transported by the transport path C towards the non-contact heating section 160 of the fuser unit.

[0225] The non-contact heating unit 160 heats the paper S having the toner image mainly by radiation from the non-contact heating heater 161. The toner image on the paper is then transported to the pressurized fixing unit 170. The pressurized fixing unit 170 forms a fixing nip with the fixing roller 172 and the pressure roller 171, and pressurizes the conveyed paper S at the fixing nip. The crystalline resin inside the toner particles that make up the toner image on the paper S melts rapidly, and as a result, the entire toner particle melts quickly with a relatively small amount of heat, and the toner components adhere to the paper S. In this way, the toner image is quickly fixed to the paper S with a relatively small amount of heat. The paper S with the toner image fixed is discharged into the output tray 50. In this way, a high-quality image is formed.

[0226] Furthermore, any remaining toner on the surface of the intermediate transfer belt 6 after secondary transfer is removed by a belt cleaning device (not shown) having a belt cleaning blade that slides against the surface of the intermediate transfer belt 6. [Examples]

[0227] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the following examples, unless otherwise specified, the operations were carried out at room temperature (25°C). Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass," respectively.

[0228] [Toner manufacturing] <Preparation of amorphous polyester resin particle dispersion 1> <<Preparation of Amorphous Polyester Resin 1>> • Bisphenol A ethylene oxide 2.2 molar adduct: 45 molar parts • Bisphenol A propylene oxide 2.2 molar adduct: 55 molar parts Dimethyl terephthalate: 60 moles • Dimethyl fumarate: 17 moles • Dodecenyl succinic anhydride: 20 moles • Trimellitus anhydride: 3 moles A reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas introduction tube was prepared. Into the reaction vessel, monomers other than dimethyl fumarate and trimellitic anhydride among the above monomers, and tin dioctylate were added in an amount of 0.23 parts by mass with respect to 100 parts by mass in total of the above monomers. After reacting at 235 °C for 6.5 hours under a nitrogen gas stream, the temperature was lowered to 200 °C, dimethyl fumarate and trimellitic anhydride were added, and the mixture was reacted for 1.5 hours. The temperature was raised to 225 °C over 5 hours, and polymerization was carried out under a pressure of 10 kPa until a desired molecular weight was obtained, and an amorphous polyester resin 1 having a pale yellow transparent color was obtained. The amorphous polyester resin 1 had a weight average molecular weight of 32,500, a number average molecular weight of 8,000, and a glass transition temperature (Tg) of 54.0 °C.

[0229] ≪Preparation of Amorphous Polyester Resin Particle Dispersion Liquid 1≫ Next, 200 parts by mass of the amorphous polyester resin 1, 95 parts by mass of methyl ethyl ketone, 40 parts by mass of isopropyl alcohol, and 7.5 parts by mass of a 10% ammonia aqueous solution were placed in a separable flask, and thoroughly mixed and dissolved. Thereafter, while heating and stirring at 40 °C, ion-exchanged water was dropped using a liquid feed pump at a liquid feed rate of 8.3 g / min, and the dropping was stopped when the liquid feed amount reached 580 parts by mass. Thereafter, solvent removal was carried out under reduced pressure to obtain an amorphous polyester resin particle dispersion liquid. Ion-exchanged water was added to the above dispersion liquid to adjust the solid content to 25% by mass, and an amorphous polyester resin particle dispersion liquid 1 was prepared. The volume-based median diameter (d ) of this amorphous polyester resin particle dispersion liquid 1 was measured with a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), and it was 135 nm.

[0230] <Preparation of Crystalline Resin Particle Dispersion Liquid 1> ≪Preparation of Crystalline Resin 1≫ · Dodecanedioic acid: 43 mol parts · 1,6-Hexanediol: 57 mol parts A reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was prepared. The monomer was placed in the reaction vessel, and the inside of the vessel was replaced with dry nitrogen gas. Next, 0.25 parts by mass of titanium tetrabutoxide (Ti(On-Bu)4) was added to 100 parts by mass of the total amount of the above monomers. The reaction was carried out by stirring at 167°C for 3.5 hours under a nitrogen gas stream, and then the temperature was further increased to 205°C over 1.5 hours. After that, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was carried out by stirring under reduced pressure for 12 hours to obtain crystalline resin 1. Crystalline resin 1 had a weight-average molecular weight of 23400, a number-average molecular weight of 7800, and a melting point of 68.3°C.

[0231] Preparation of Crystalline Resin Particle Dispersion 1 Next, 200 parts by mass of this crystalline resin 1, 115 parts by mass of methyl ethyl ketone, and 35 parts by mass of isopropyl alcohol were placed in a separable flask and thoroughly mixed and dissolved at 60°C. Then, 8 parts by mass of 10% by mass aqueous ammonia solution were added dropwise. The heating temperature was lowered to 67°C, and deionized water was added dropwise using a liquid transfer pump at a rate of 8.5 g / min while stirring. The addition of deionized water was stopped when the volume reached 580 parts by mass. Subsequently, the solvent was removed under reduced pressure to obtain a dispersion of crystalline resin particles. Deionized water was added to the above dispersion to adjust the solid content to 25% by mass, and crystalline resin particle dispersion 1 was prepared. The median diameter (d) of this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 165 nm.

[0232] <Preparation of Crystalline Resin Particle Dispersion 2> <<Preparation of Crystalline Resin 2>> The raw material monomers for the addition polymerization resin, both reactive monomers, and the radical polymerization initiator listed below were placed in a dropper funnel. Styrene: 50 parts by mass Butyl acrylate: 15 parts by mass • Acrylic acid: 6 parts by mass • Di-tert-butyl peroxide: 5.5 parts by mass Furthermore, 560 parts by mass of stearyl methacrylate were placed in a four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 165°C to dissolve it. Next, the raw material monomers for the addition polymerization resin were added dropwise over 90 minutes under stirring, and the mixture was allowed to mature for 90 minutes. After that, unreacted addition polymerization monomers were removed under reduced pressure (8 kPa) to obtain crystalline resin 2. The obtained crystalline resin 2 had a weight-average molecular weight (Mw) of 23,500, a number-average molecular weight of 7,900, and a melting point of 76.5°C.

[0233] Preparation of Crystalline Resin Particle Dispersion 2 Next, 200 parts by mass of this crystalline resin 2, 115 parts by mass of methyl ethyl ketone, and 35 parts by mass of isopropyl alcohol were placed in a separable flask and thoroughly mixed and dissolved at 60°C. Then, 8 parts by mass of 10% by mass aqueous ammonia solution were added dropwise. The heating temperature was lowered to 67°C, and while stirring, deionized water was added dropwise using a liquid transfer pump at a rate of 8 g / min. When the amount of liquid transferred reached 580 parts by mass, the addition of deionized water was stopped. Subsequently, the solvent was removed under reduced pressure to obtain a crystalline resin particle dispersion. Deionized water was added to the above dispersion to adjust the solid content to 25% by mass, and crystalline resin particle dispersion 2 was prepared. The median diameter (d) of this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 180 nm.

[0234] <Preparation of vinyl resin particle dispersion 1> The following monomers and release agents were placed in a stainless steel beaker and the internal temperature was raised to 85°C to melt them. (Monomer and mold release agent solution) Styrene (St): 78 parts by mass n-butyl acrylate (BA): 19 parts by mass • Methacrylic acid (MAA): 3 parts by mass • Ester wax "Electol WEP-3" (manufactured by Nippon Oil & Fats Co., Ltd.): 31 parts by mass Furthermore, an aqueous surfactant solution prepared by dissolving 7.6 parts by mass of polyoxyethylene lauryl ether sodium sulfate (40% active ingredient) in 291.5 parts by mass of pure water was similarly heated to an internal temperature of 85°C. The above-mentioned monomer and release agent solution were added to this surfactant aqueous solution, and emulsification was performed by high-speed stirring to obtain an emulsion. The emulsion was placed in a flask equipped with a stirrer, a nitrogen inlet tube, and a temperature sensor, and the internal temperature was raised to 80°C under a nitrogen stream while stirring. Subsequently, the following polymerization initiator aqueous solution was added. (Polymerization initiator aqueous solution) Potassium persulfate: 1.75 parts by mass Pure water: 41 parts by mass Subsequently, 1.36 parts by mass of n-octyl mercaptan were divided into four portions and added at 10-minute intervals. Polymerization was then carried out for 1 hour under a nitrogen stream while maintaining an internal temperature of 80°C. Next, the following monomer solutions and polymerization initiator aqueous solutions were prepared. (Monomer solution) Styrene: 70 parts by mass n-butyl acrylate: 26 parts by mass • Methacrylic acid: 4 parts by mass n-octyl mercaptan: 1.36 parts by mass (Polymerization initiator aqueous solution) • Potassium persulfate: 1.89 parts by mass ·Pure water: 35.85 parts by mass After adding the polymerization initiator aqueous solution to the flask described above, the monomer solution was added dropwise over 90 minutes. After the addition of the monomer solution was complete, polymerization was carried out at an internal temperature of 80°C for 2 hours, and then the internal temperature was raised to 87°C to complete the polymerization. After cooling the internal temperature to room temperature, the solution was filtered and the solid content concentration was adjusted to 20% to obtain vinyl resin particle dispersion 1. The glass transition temperature (Tg) of the vinyl resin in vinyl resin particle dispersion 1 was 46°C, and the weight-average molecular weight (Mw) was 18000. The volume-based median diameter (d) of this dispersion was also determined. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 210 nm.

[0235] <Preparation of mold release agent particle dispersion 1> Paraffin wax (FNP0090, manufactured by Nippon Seiro, melting point 89°C): 260 parts by mass • Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku): 13.0 parts by mass (60% active ingredient, 3% relative to the release agent) • Ion-exchanged water: 21.6 parts by mass The above materials were mixed, and the release agent was dissolved in a pressure-discharge homogenizer (Gorin homogenizer, manufactured by Gorin Corporation) at an internal liquid temperature of 120°C. The mixture was then dispersed at a dispersion pressure of 5 MPa for 120 minutes, followed by 40 MPa for 360 minutes. After cooling, a dispersion was obtained. Deionized water was added to adjust the solid content to 20%, and this was designated as release agent particle dispersion 1. The volume-average particle diameter of the particles in release agent particle dispersion 1 was 190 nm.

[0236] <Preparation of a dispersion of coloring agent particles> Preparation of Yellow Colorant Dispersion 1 CI Pigment Yellow 74:100 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 16 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed and pre-dispersed for 10 minutes using a homogenizer (ULTRA-TURRAX T50, IKA). Then, a high-pressure impact disperser (Ultimaizer, Sugino Machine) was used to disperse the particles at a pressure of 245 MPa for 30 minutes to obtain an aqueous dispersion of yellow colorant particles. Deionized water was then added to the resulting dispersion to adjust the solid content to 15% by mass, thereby preparing yellow colorant dispersion 1. The median diameter (d) of the colorant particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 45 nm.

[0237] Preparation of Magenta Colorant Dispersion 1 CI Pigment Red 122: 35 parts by mass CI Pigment Red 238: 65 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 16 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed, and magenta colorant dispersion 1 was prepared in the same manner as the preparation of yellow colorant dispersion 1. The median diameter (d) of the colorant particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 65 nm.

[0238] Preparation of Cyanide Colorant Dispersion 1 CI Pigment Blue 15:3 : 100 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 16 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed, and cyan colorant dispersion 1 was prepared in the same manner as the preparation of yellow colorant dispersion 1. The median diameter (d) of the colorant particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 55 nm.

[0239] Preparation of Black Colorant Dispersion 1 • Carbon black (Cabot Corporation, Regal® 330): 95 parts by mass CI Pigment Blue 15:3 :5 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 16 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed, and black colorant dispersion 1 was prepared in the same manner as the preparation of yellow colorant dispersion 1. The median diameter (d) of the colorant particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 50 nm.

[0240] Preparation of Red Colorant Dispersion 1 CI Pigment Orange 38: 50 parts by mass · C.I. Pigment Red 185: 50 parts by mass · Anionic surfactant (Neogen SC manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 16 parts by mass · Ion-exchanged water: 400 parts by mass The above components were mixed, and Red Colorant Dispersion Liquid 1 was prepared in the same manner as the preparation of Yellow Colorant Dispersion Liquid 1. When the volume-based median diameter (d 50 ) of the colorant particles in this dispersion liquid was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), it was 64 nm.

[0241] ≪Preparation of Green Colorant Dispersion Liquid 1≫ · C.I. Pigment Green 36: 100 parts by mass · Anionic surfactant (Neogen SC manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 16 parts by mass · Ion-exchanged water: 400 parts by mass The above components were mixed, and Green Colorant Dispersion Liquid 1 was prepared in the same manner as the preparation of Yellow Colorant Dispersion Liquid 1. When the volume-based median diameter (d 50 ) of the colorant particles in this dispersion liquid was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), it was 54 nm.

[0242] ≪Preparation of Green Colorant Dispersion Liquid 2≫ · C.I. Pigment Green 36: 85 parts by mass · C.I. Pigment Yellow 101: 15 parts by mass · Anionic surfactant (Neogen SC manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 16 parts by mass · Ion-exchanged water: 400 parts by mass The above components were mixed, and Green Colorant Dispersion Liquid 2 was prepared in the same manner as the preparation of Yellow Colorant Dispersion Liquid 1. When the volume-based median diameter (d 50 ) of the colorant particles in this dispersion liquid was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), it was 58 nm.

[0243] ≪Preparation of Pink Colorant Dispersion Liquid 1≫ · C.I. Pigment Red 168: 100 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 16 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed, and pink colorant dispersion 1 was prepared in the same manner as the preparation of yellow colorant dispersion 1. The median diameter (d) of the colorant particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 70 nm.

[0244] Preparation of Orange Coloring Agent Dispersion 1 CI Pigment Orange 38: 100 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 16 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed, and orange colorant dispersion 1 was prepared in the same manner as the preparation of yellow colorant dispersion 1. The median diameter (d) of the colorant particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was 69 nm.

[0245] Preparation of Luminous Colorant Dispersion 1 (Preparation of aluminum pigment 1) 500 parts by mass of methanol were mixed with 235 parts by mass of aluminum powder having an average particle size of 4.0 μm, and the mixture was stirred at 60°C for 1.5 hours. Then, ammonia was added to the slurry to adjust its pH to 8.0. Next, 50 parts by mass of tetraethoxysilane were added to the pH-adjusted slurry, and the mixture was stirred at 60°C for a further 5 hours. The slurry was then filtered, and the resulting slurry containing the coated aluminum pigment was dried at 110°C for 3 hours to obtain silica-coated aluminum pigment 1.

[0246] (Preparation of Luminous Colorant Dispersion 1) Aluminum pigment 1:100 parts by mass Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku): 2.0 parts by mass • Ion-exchanged water: 900 parts by mass The above ingredients were mixed and dispersed for 1 hour using a Cavitron emulsifying and dispersing machine (CR1010, manufactured by Taiheiyo Kiko Co., Ltd.) to prepare a luminous colorant dispersion 1 (solid content concentration: 10%). The median diameter (d) of the colorant particles in this dispersion was measured by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the size was found to be 8.0 μm.

[0247] Preparation of White Coloring Agent Dispersion 1 (Preparation of titanium dioxide pigment 1) Titanium dioxide nanoparticles obtained by the sulfuric acid method were surface-treated (coated) with alumina, with an average major axis length of 250 nm and a BET specific surface area of ​​8 m². 2 Titanium dioxide pigment 1 was obtained in a quantity of / g.

[0248] (Preparation of white coloring agent dispersion 1) Titanium dioxide pigment 1:100 parts by mass Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Industries, Ltd.): 10 parts by mass • Ion-exchanged water: 400 parts by mass The above components were mixed and stirred for 30 minutes using a homogenizer (Ultra-Turrax T50: IKA Corporation). Then, the mixture was dispersed for 1 hour using a high-pressure impact disperser Ultimizer (HJP30006: Sugino Machine Co., Ltd.) to prepare white coloring agent dispersion 1 (solid content concentration: 20%). The median diameter (d) of the coloring agent particles in this dispersion was determined by volume. 50 When measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the value was found to be 150 nm.

[0249] The abbreviations used in the table below are as follows: PY74 (CI Pigment Yellow 74) PR122 (CI Pigment Red 122) PR238 (CI Pigment Red 238) PB15:3 (CI Pigment Blue 15:3) PO38 (CI Pigment Orange 38) PR185 (CI Pigment Red 185) PG36 (CI Pigment Green 36) PY101 (CI Pigment Yellow 101) PR168 (CI Pigment Red 168) PO38 (CI Pigment Orange 38)

[0250] [Table 1]

[0251] <Preparation of Yellow Toner Base Particle 1> ≪Agglomeration / fusion process≫ • Amorphous polyester resin particle dispersion 1:1170 parts by mass • Vinyl resin particle dispersion 1:40 parts by mass • Release agent particle dispersion 1:134 parts by mass • Yellow colorant dispersion 1:195 parts by mass • Anionic surfactant (Dowfax 2A1 20% aqueous solution): 40 parts by mass • Ion-exchanged water: 1500 parts by mass The above materials were placed in a 4-liter reaction vessel equipped with a thermometer, pH meter, and stirrer, and 1.0% nitric acid was added at a temperature of 25°C to adjust the pH to 3.0. Subsequently, 100 parts by mass of a 2% aluminum sulfate (coagulant) aqueous solution was added over 30 minutes while dispersing the mixture at 3000 rpm using a homogenizer (ULTRA-TURRAX T50, manufactured by IKA). After the dropwise addition was complete, the mixture was stirred for 10 minutes to thoroughly mix the raw materials and the flocculant. Then, a stirrer and mantle heater were installed in the reaction vessel. The temperature was increased at a rate of 0.2°C / min up to 40°C, and then at a rate of 0.05°C / min above 40°C, while adjusting the stirrer speed to ensure the slurry was thoroughly mixed. The particle size was measured every 10 minutes using a Coulter Multisizer 3 (aperture diameter 100 μm, manufactured by Beckman Coulter).

[0252] <<Shell particle fusion process and maturation process>> When the volume-based median diameter reached 5.7 μm, the temperature was maintained, and the following pre-mixed solution was added over a period of 20 minutes. • Amorphous polyester resin particle dispersion 1:400 parts by mass • Anionic surfactant (Dowfax 2A1 20% aqueous solution): 15 parts by mass Next, after holding at 50°C for 30 minutes, 9 parts by mass of 20% EDTA (ethylenediaminetetraacetic acid) solution were added to the reaction vessel, and a 1 mol / L sodium hydroxide aqueous solution was added to control the pH of the raw material dispersion to 9.0. Subsequently, the temperature was raised to 85°C at a rate of 1°C / min while adjusting the pH to 9.0 every 5°C, and the mixture was held at 85°C.

[0253] ≪Cooling process≫ Subsequently, using "FPIA-3000," the mixture was cooled at a rate of 10°C / min when the shape factor reached 0.963, to obtain yellow toner matrix particle dispersion 1.

[0254] ≪Filtration, washing, and drying processes≫ The yellow toner matrix particle dispersion 1 was filtered and thoroughly washed with deionized water. Then, it was dried at 40°C to obtain yellow toner matrix particles 1. The obtained yellow toner matrix particles 1 had a volume-average particle diameter of 5.8 μm and a shape factor of 0.963.

[0255] <Preparation of Yellow Toner Base Particles 2> Yellow toner matrix particles 2 were obtained in the same manner as in the preparation of yellow toner matrix particles 1, except that the following materials were used in the aggregation and fusion process. • Amorphous polyester resin particle dispersion 1:10 10 parts by mass ·Crystalline resin particle dispersion 1:160 parts by mass • Vinyl resin particle dispersion 1:40 parts by mass • Release agent particle dispersion 1:134 parts by mass • Yellow colorant dispersion 1:195 parts by mass • Anionic surfactant (Dowfax 2A1 20% aqueous solution): 40 parts by mass • Ion-exchanged water: 1500 parts by mass

[0256] <Preparation of Yellow Toner Base Particles 3> Yellow toner matrix particles 3 were obtained in the same manner as in the preparation of yellow toner matrix particles 2, except that crystalline resin particle dispersion 2 was used instead of crystalline resin particle dispersion 1.

[0257] <Preparation of Yellow Toner Matrix Particles 4> Yellow toner matrix particles 4 were obtained in the same manner as in the preparation of yellow toner matrix particles 1, except that vinyl resin dispersion 1 was not used.

[0258] <Preparation of magenta toner matrix particles 1, cyan toner matrix particles 1, and black toner matrix particles 1> In the preparation of yellow toner matrix particles 1, magenta toner matrix particles 1, cyan toner matrix particles 1, and black toner matrix particles 1 were obtained in the same manner as described in the table, except that the dispersion liquid listed in the table was used instead of the yellow colorant dispersion liquid 1.

[0259] <Preparation of magenta toner matrix particles 2, cyan toner matrix particles 2, and black toner matrix particles 2> In the preparation of yellow toner matrix particles 2, magenta toner matrix particles 2, cyan toner matrix particles 2, and black toner matrix particles 2 were obtained in the same manner, except that the dispersion liquid listed in the table was used instead of yellow colorant dispersion liquid 1.

[0260] <Preparation of magenta toner matrix particles 3, cyan toner matrix particles 3, and black toner matrix particles 3> In the preparation of yellow toner matrix particles 3, magenta toner matrix particles 3, cyan toner matrix particles 3, and black toner particles 3 were obtained in the same manner, except that the dispersion liquid listed in the table was used instead of yellow colorant dispersion liquid 1.

[0261] <Preparation of magenta toner matrix particles 4, cyan toner matrix particles 4, and black toner matrix particles 4> In the preparation of yellow toner matrix particles 4, magenta toner matrix particles 4, cyan toner matrix particles 4, and black toner matrix particles 4 were obtained in the same manner, except that the dispersion liquid listed in the table was used instead of yellow colorant dispersion liquid 1.

[0262] <Preparation of Red Toner Matrix Particles 1> In the preparation of yellow toner matrix particles 2, red toner matrix particles 1 were obtained in the same manner as above, except that red colorant dispersion 1 was used instead of yellow colorant dispersion 1.

[0263] <Preparation of Green Toner Matrix Particles 1> In the preparation of yellow toner matrix particles 2, green toner matrix particles 1 were obtained in the same manner as above, except that green colorant dispersion 1 was used instead of yellow colorant dispersion 1.

[0264] <Preparation of Green Toner Mathematical Particles 2> In the preparation of yellow toner matrix particles 2, green toner matrix particles 2, pink toner matrix particles 1, and orange toner matrix particles 1 were obtained in the same manner as in the preparation of yellow toner matrix particles 2, except that green colorant dispersion 2 was used instead of yellow colorant dispersion 1.

[0265] <Preparation of Pink Toner Base Particle 1> In the preparation of yellow toner matrix particles 2, pink toner matrix particles 1 were obtained in the same manner as before, except that pink colorant dispersion 1 was used instead of yellow colorant dispersion 1.

[0266] <Preparation of Orange Toner Base Particles 1> In the preparation of yellow toner matrix particles 2, orange toner matrix particles 1 were obtained in the same manner as above, except that orange colorant dispersion 1 was used instead of yellow colorant dispersion 1.

[0267] <Preparation of Gold Toner Matrix Particles 1> ≪Agglomeration / fusion process≫ • 1:800 parts by mass of a dispersion of luminous colorants • Yellow colorant dispersion 1:60 parts by mass • Red colorant dispersion 1:20 parts by mass • Amorphous polyester resin particle dispersion 1:750 parts by mass • Vinyl resin dispersion 1:20 parts by mass • Release agent particle dispersion 1:100 parts by mass The above components were placed in a 4L cylindrical stainless steel container and mixed by dispersing them for 10 minutes while applying shear force at 4000 rpm using a homogenizer (IKA Ultra Lalux T50). Next, 3.50 parts by mass of a 10% nitric acid aqueous solution of aluminum sulfate (coagulant) was gradually added dropwise, and the mixture was dispersed and mixed for 15 minutes at a homogenizer rotation speed of 5000 rpm. Subsequently, the above mixture was transferred to a reactor equipped with a stirring device using two paddle blades and a thermometer. The mixture was heated at a stirring speed of 1100 rpm and maintained at 54°C to promote coagulation. During this time, the pH of the dispersion was controlled within the range of 2.0 to 3.5 using 0.3N nitric acid and 1N sodium hydroxide aqueous solution, and maintained for about 2 hours. At this time, the volume-average particle size of the coagulated particles, measured using a Multisizer II (aperture diameter: 50 μm, manufactured by Coulter), was 10.4 μm.

[0268] <<Shell particle fusion process and maturation process>> An amorphous polyester resin particle dispersion was added in a ratio of 1:250 parts by mass to adhere the amorphous polyester resin particles to the surface of the aggregated particles. The temperature was further increased to 57°C and maintained until the amorphous polyester resin particles had completely adhered. Subsequently, a 0.1 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 8.0, and the temperature was raised to 68°C. The mixture was then maintained until the amorphous polyester resin particles dissolved into aggregated particles. Afterward, the pH was lowered to 6.0, held at that level for one hour, and then heating was stopped.

[0269] Cooling process, filtration / washing process, and drying process The mixture was cooled at a rate of 1.0°C / min. Afterward, it was sieved through a 40 μm mesh, washed repeatedly with water, and then dried in a vacuum dryer to obtain toner matrix particles. The volume-average particle size of the obtained toner matrix particles was 12.0 μm.

[0270] <Preparation of Gold Toner Mathematical Particles 2> Gold toner particles 2 were obtained in the same manner as in the preparation of gold toner matrix particles 1, except that the following materials were used in the aggregation and fusion process. • 1:800 parts by mass of a dispersion of luminous colorants • Yellow colorant dispersion 1:60 parts by mass • Red colorant dispersion 1:20 parts by mass • Amorphous polyester resin particle dispersion 1:630 parts by mass ·Crystalline resin particle dispersion 1:120 parts by mass • Vinyl resin dispersion 1:20 parts by mass • Release agent particle dispersion: 100 parts by mass

[0271] <Preparation of Silver Toner Base Particles 1> In the preparation of gold toner matrix particles 1, silver toner matrix particles 1 were obtained in the same manner as in the preparation of gold toner matrix particles 1, except that yellow colorant dispersion 1 and red colorant dispersion 1 were not used.

[0272] <Preparation of Silver Toner Matrix Particles 2> In the preparation of gold toner matrix particles 2, silver toner matrix particles 1 were obtained in the same manner as above, except that yellow colorant dispersion 1 and red colorant dispersion 1 were not used.

[0273] <Preparation of White Toner Matrix Particles 1> ≪Agglomeration / fusion process≫ • Amorphous polyester resin particle dispersion 1:10 10 parts by mass ·Crystalline resin particle dispersion 1:160 parts by mass • Vinyl resin particle dispersion 1:40 parts by mass • Release agent particle dispersion 1:134 parts by mass • White coloring agent dispersion 1:600 ​​parts by mass • Anionic surfactant (Dowfax 2A1 20% aqueous solution): 40 parts by mass • Ion-exchanged water: 1500 parts by mass The above materials were placed in a 4-liter reaction vessel equipped with a thermometer, pH meter, and stirrer, and 1.0% nitric acid was added at a temperature of 25°C to adjust the pH to 3.0. Subsequently, 100 parts by mass of a 2% aluminum sulfate (coagulant) aqueous solution was added over 30 minutes while dispersing the mixture at 3000 rpm using a homogenizer (ULTRA-TURRAX T50, manufactured by IKA). After the dropwise addition was complete, the mixture was stirred for 10 minutes to thoroughly mix the raw materials and the flocculant. Then, a stirrer and mantle heater were installed in the reaction vessel. The temperature was increased at a rate of 0.2°C / min up to 40°C, and then at a rate of 0.05°C / min above 40°C, while adjusting the stirrer speed to ensure the slurry was thoroughly mixed. The particle size was measured every 10 minutes using a Coulter Multisizer 3 (aperture diameter 100 μm, manufactured by Beckman Coulter).

[0274] <<Shell particle fusion process and maturation process>> When the volume-based median diameter reached 6.5 μm, the temperature was maintained, and the following pre-mixed solution was added over a period of 20 minutes. • Amorphous polyester resin particle dispersion 1:400 parts by mass • Anionic surfactant (Dowfax 2A1 20% aqueous solution): 15 parts by mass Next, after holding at 50°C for 30 minutes, 9 parts by mass of 20% EDTA (ethylenediaminetetraacetic acid) solution were added to the reaction vessel, and a 1 mol / L sodium hydroxide aqueous solution was added to control the pH of the raw material dispersion to 9.0. Subsequently, the temperature was raised to 85°C at a rate of 1°C / min while adjusting the pH to 9.0 every 5°C, and the mixture was held at 85°C.

[0275] ≪Cooling process≫ Subsequently, using "FPIA-3000," the mixture was cooled at a rate of 10°C / min when the shape factor reached 0.938, to obtain white toner matrix particle dispersion 1.

[0276] ≪Filtration, washing, and drying processes≫ The aforementioned white toner matrix particle dispersion 1 was filtered and thoroughly washed with deionized water. Then, it was dried at 40°C to obtain white toner matrix particles 1. The obtained white toner matrix particles 1 had a volume-average particle diameter of 7.1 μm and a shape factor of 0.938.

[0277] [Table 2]

[0278] <Preparation of silica particles A1> ·Process (1) In a 3-liter reactor equipped with a stirrer, dropping funnel, and thermometer, 1258.4 parts by mass of ethanol, 460.5 parts by mass of water, and 6.1 parts by mass of ammonia were added and mixed. This solution was heated to 35°C, and 75.0 parts by mass of tetraethoxysilane were hydrolyzed while stirring to obtain a suspension of silica fine particles. Next, the mixture was heated to 70-80°C, and 700 parts by mass of ethanol were removed by distillation to obtain an aqueous suspension of silica fine particles. ·Process (2) To this aqueous suspension, methyltrimethoxysilane (5.48 parts by mass in this case), in a molar ratio of 0.1 to tetraethoxysilane, was added dropwise at room temperature to treat the surface of the silica nanoparticles. ·Process (3) To the resulting dispersion, 1400 parts by mass of methyl isobutyl ketone was added, and the mixture was heated to 85°C and the ethanol water was removed by distillation. To the resulting dispersion, 22.5 parts by mass of hexamethyldisilazane was added at room temperature, and the mixture was heated to 120°C and reacted for 3 hours to trimethylsilylate the silica nanoparticles. Subsequently, the solvent was removed under reduced pressure to prepare silica particles, obtaining silica particles A1 with a number-average particle size of 50 nm.

[0279] <Preparation of Silica Particles A2> Silica particles A2 were obtained in the same manner as in the preparation of silica particles A1, except that 1297.3 parts by mass of ethanol and 421.6 parts by mass of water were used.

[0280] <Preparation of Silica Particles A3> Silica particles A3 were obtained in the same manner as in the preparation of silica particles A1, except that 1388.1 parts by mass of ethanol and 330.8 parts by mass of water were used.

[0281] <Preparation of Silica Particles A4> Silica particles A4 were obtained in the same manner as in the preparation of silica particles A1, except that 1397.8 parts by mass of ethanol and 321.0 parts by mass of water were used.

[0282] <Preparation of Silica Particles A5> Silica particles A5 were obtained in the same manner as in the preparation of silica particles A1, except that 1475.7 parts by mass of ethanol and 243.2 parts by mass of water were used.

[0283] <Preparation of Silica Particles A6> Silica particles A6 were obtained in the same manner as in the preparation of silica particles A1, except that 1166.9 parts by mass of ethanol, 583.7 parts by mass of water, 30.7 parts by mass of ammonia, 18.7 parts by mass of tetraethoxysilane, 1.37 parts by mass of trimethylmethoxysilane, and 5.62 parts by mass of hexamethyldisilazane were used.

[0284] <Preparation of Silica Particles A7> In the preparation of silica particles A1, 1183.1 parts by mass of ethanol, 567.5 parts by mass of water, 30.7 parts by mass of ammonia, 18.7 parts by mass of tetraethoxysilane, 1.37 parts by mass of trimethylmethoxysilane, and 5.62 parts by mass of hexamethyldisilazane were used, and silica particles A7 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 65°C.

[0285] <Preparation of Silica Particles A8> In the preparation of silica particles A1, 1147.5 parts by mass of ethanol, 603.1 parts by mass of water, 30.7 parts by mass of ammonia, 18.7 parts by mass of tetraethoxysilane, 1.37 parts by mass of trimethylmethoxysilane, and 5.62 parts by mass of hexamethyldisilazane were used, and silica particles A8 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 90°C.

[0286] <Preparation of Silica Particles A9> In the preparation of silica particles A1, 1166.9 parts by mass of ethanol, 583.7 parts by mass of water, 30.7 parts by mass of ammonia, 18.7 parts by mass of tetraethoxysilane, 1.37 parts by mass of trimethylmethoxysilane, and 5.62 parts by mass of hexamethyldisilazane were used, and silica particles A9 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 90°C.

[0287] <Preparation of silica particles A10> In the preparation of silica particles A1, 1368.0 parts by mass of ethanol, 382.65 parts by mass of water, 30.7 parts by mass of ammonia, 18.7 parts by mass of tetraethoxysilane, 1.37 parts by mass of trimethylmethoxysilane, and 5.62 parts by mass of hexamethyldisilazane were used, and silica particles A10 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 85°C.

[0288] <Preparation of silica particles A11> In the preparation of silica particles A1, 1377.7 parts by mass of ethanol, 372.95 parts by mass of water, 30.7 parts by mass of ammonia, 18.7 parts by mass of tetraethoxysilane, 1.37 parts by mass of trimethylmethoxysilane, and 5.62 parts by mass of hexamethyldisilazane were used, and silica particles A11 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 85°C.

[0289] <Preparation of Silica Particles A12> In the preparation of silica particles A1, 1362.0 parts by mass of ethanol, 356.7 parts by mass of water, 30.7 parts by mass of ammonia, 50.6 parts by mass of tetraethoxysilane, 3.70 parts by mass of trimethylmethoxysilane, and 15.2 parts by mass of hexamethyldisilazane were used, and silica particles A12 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 85°C.

[0290] <Preparation of silica particles A13> In the preparation of silica particles A1, 1352.6 parts by mass of ethanol, 356.7 parts by mass of water, 30.7 parts by mass of ammonia, 60.0 parts by mass of tetraethoxysilane, 4.38 parts by mass of trimethylmethoxysilane, and 18.0 parts by mass of hexamethyldisilazane were used, and silica particles A13 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 85°C.

[0291] <Preparation of Silica Particles A14> In the preparation of silica particles A1, 1264.5 parts by mass of ethanol, 356.7 parts by mass of water, 30.7 parts by mass of ammonia, 148.1 parts by mass of tetraethoxysilane, 10.8 parts by mass of trimethylmethoxysilane, and 44.4 parts by mass of hexamethyldisilazane were used, and silica particles A14 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 75°C.

[0292] <Preparation of Silica Particles A15> In the preparation of silica particles A1, 1261.5 parts by mass of ethanol, 356.7 parts by mass of water, 30.7 parts by mass of ammonia, 151.1 parts by mass of tetraethoxysilane, 11.0 parts by mass of trimethylmethoxysilane, and 45.3 parts by mass of hexamethyldisilazane were used, and silica particles A15 were obtained in the same manner except that the temperature during the distillation of ethanol from the suspension in step (1) was 75°C.

[0293] [Table 3]

[0294] <Preparation of Silica Particles B1> ·Process (1) In a 3-liter reactor equipped with a stirrer, dropping funnel, and thermometer, 989.3 parts by mass of ethanol, 729.6 parts by mass of water, and 6.1 parts by mass of ammonia were added and mixed. This solution was heated to 35°C, and 75.0 parts by mass of tetraethoxysilane were hydrolyzed while stirring to obtain a suspension of silica fine particles. Next, the mixture was heated to 70-80°C, and 400 parts by mass of ethanol were removed by distillation to obtain an aqueous suspension of silica fine particles. ·Process (2) To this aqueous suspension, methyltrimethoxysilane (5.48 parts by mass in this case), in a molar ratio of 0.1 to tetramethoxysilane, was added dropwise at room temperature to treat the surface of the silica nanoparticles. ·Process (3) To the resulting dispersion, 1400 parts by mass of methyl isobutyl ketone was added, and the mixture was heated to 85°C and the ethanol water was removed by distillation. To the resulting dispersion, 22.5 parts by mass of hexamethyldisilazane was added at room temperature, and the mixture was heated to 120°C and reacted for 3 hours to trimethylsilylate the silica nanoparticles. Subsequently, the solvent was removed under reduced pressure to prepare silica particles, obtaining silica particles B1 with a number-average particle size of 18 nm.

[0295] <Preparation of Silica Particles B2> In the preparation of silica particles B1, 1037.9 parts by mass of ethanol and 681.0 parts by mass of water were used, and the temperature during the distillation of ethanol from the suspension in step (1) was set to 75°C, but otherwise silica particles B1 were obtained in the same manner.

[0296] <Preparation of Silica Particles B3> Silica particles B3 were obtained in the same manner as in the preparation of silica particles B1, except that 1144.9 parts by mass of ethanol and 574.0 parts by mass of water were used.

[0297] <Preparation of Silica Particles B4> Silica particles B4 were obtained in the same manner as in the preparation of silica particles B1, except that 1138.4 parts by mass of ethanol and 580.4 parts by mass of water were used.

[0298] <Preparation of Silica Particles B5> In the preparation of silica particles B1, silica particles B5 was obtained by the same procedure except that 1151.4 parts by mass of ethanol and 567.5 parts by mass of water were used.

[0299] <Preparation of Silica Particles B6> In the preparation of silica particles B1, silica particles B6 was obtained in the same manner as above, except that 1183.8 parts by mass of ethanol and 535.0 parts by mass of water were used, and the temperature during the distillation of ethanol from the suspension in step (1) was set to 65°C.

[0300] <Preparation of Silica Particles B7> In the preparation of silica particles B1, silica particles B7 was obtained in the same manner as above, except that 1200.0 parts by mass of ethanol and 518.8 parts by mass of water were used, and the temperature during the distillation of ethanol from the suspension in step (1) was set to 85°C.

[0301] The number-average particle size and average circularity of the primary particles of silica particles A and silica particles B were calculated as described above.

[0302] [Table 4]

[0303] <Preparation of Zinc Stearate Particles 1> A 15% by mass aqueous solution A1 was prepared by dissolving sodium stearate in water. A 25% by mass aqueous solution B1 was prepared by dissolving zinc sulfate in water. A 2-liter receiving container equipped with a stirring device having a turbine blade with a diameter of 6 cm was prepared, and the turbine blade was rotated at 350 rpm. Aqueous solution A1 was poured into this receiving container, and the liquid temperature was adjusted to 80°C. Next, aqueous solution B1 was added dropwise to the receiving container over a period of 30 minutes. After the entire mixture had been added, the mixture was allowed to mature for 10 minutes at the temperature at which the reaction occurred to terminate the reaction. Next, the metal soap slurry obtained in this manner was filtered, the resulting metal soap cake was washed three times with water, and the zinc stearate cake was dried at atmospheric pressure at 100°C to obtain zinc stearate particles 1 (ZnSt particles 1).

[0304] <Preparation of Zinc Stearate Particles 2> Sodium stearate was dissolved in water to prepare aqueous solution A2 with a concentration of 10% by mass. Zinc sulfate was also dissolved in water to prepare aqueous solution B2 with a concentration of 3.0% by mass. Next, aqueous solutions A2 and B2, both adjusted to 85°C, were supplied separately into a pipeline homomixer. The mixed solution discharged from the pipeline homomixer was then poured into a 2-liter receiving container equipped with a stirring device having a 6 cm diameter turbine blade, while the turbine blade rotated at 350 rpm. The flow rate of each solution was adjusted using a metering pump so that each solution would be delivered simultaneously. The total mixing time was limited to within 10 minutes. After the entire mixture was prepared, the reaction was terminated by aging for 10 minutes while maintaining the reaction temperature. The resulting zinc stearate slurry was filtered, and the resulting zinc stearate cake was washed three times with water. The resulting washed zinc stearate cake was dried under reduced pressure at 50°C to obtain zinc stearate particles 2 (ZnSt particles 2).

[0305] <Preparation of calcium stearate particles 1> A 1-liter, resealable reaction vessel equipped with a stirring device capable of mixing highly viscous substances was prepared, and 500 parts by mass of stearic acid were added to the reaction vessel. Subsequently, the stirring device was rotated at 50 rpm to adjust the temperature to 70°C. Next, 68 parts by mass of calcium hydroxide and 10 parts by mass of water were added to the reaction vessel, and the vessel was sealed. The reaction was carried out for 180 minutes while the stirring device was running. The calcium stearate obtained in this way was thoroughly ground in a mixer and classified using a JIS standard sieve with a preliminary size of 45 μm to obtain calcium stearate particles 1 (CaSt particles 1).

[0306] <Preparation of Zinc Stearate Lubricant Rod 1> A 1-liter, resealable reaction vessel equipped with a stirring device capable of mixing highly viscous substances was prepared, and 500 parts by mass of stearic acid were added to the reaction vessel. Subsequently, the stirring device was rotated at 50 rpm to adjust the temperature to 70°C. Next, 75 parts by mass of calcium hydroxide and 10 parts by mass of water were added to the reaction vessel, and the reaction vessel was sealed. The reaction was carried out for 180 minutes while the stirring device was running. The sodium stearate obtained in this way was poured into a mold and solidified by cooling to obtain zinc stearate lubricant rod 1. The number-average particle size and melting point of the obtained fatty acid metal salts were measured using the method described above.

[0307] [Table 5]

[0308] <Preparation of Yellow Toner 1> Yellow toner 1 was prepared by adding 1.92 parts by mass of silica particle A6, 0.95 parts by mass of silica particle B4, 1.0 part by mass of hydrophobic silica (number-average primary particle size 12 nm, degree of hydrophobicity 68), and 0.50 parts by mass of zinc stearate particle 2 to 1 / 100 parts by mass of yellow toner matrix particles. This mixture was then added to a Henschel mixer model "FM20C / I" (manufactured by Nippon Coke Industries Co., Ltd.), and the mixture was stirred for 20 minutes at a rotation speed set to a blade tip peripheral speed of 50 m / s. The moisture content of yellow toner 1 under low temperature and low humidity conditions was 0.65% by mass. The method for measuring the moisture content of the toner will be described later.

[0309] <Preparation of Yellow Toner 2-42> In the preparation of yellow toner 1, the yellow toner matrix particles listed in the table were used instead of yellow toner matrix particles 1. Furthermore, yellow toners 2 to 42 were prepared in the same manner, except that the types and amounts of silica particles A, silica particles B, and fatty acid metal salts listed in the table were used.

[0310] <Preparation of Magenta Toner 1> Magenta toner 1 was prepared in the same manner as yellow toner 1, except that magenta toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0311] <Preparation of Magenta Toner 2-42> In the preparation of magenta toner 1, the magenta toner matrix particles listed in the table were used instead of magenta toner matrix particles 1. Furthermore, magenta toners 2 to 42 were prepared in the same manner, except that the types and amounts of silica particles A, silica particles B, and fatty acid metal salts listed in the table were used.

[0312] <Preparation of Cyan Toner 1> Cyan toner 1 was prepared in the same manner as in the preparation of yellow toner 1, except that cyan toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0313] <Preparation of Cyanon Toner 2-42> In the preparation of cyan toner 1, the cyan toner matrix particles listed in the table were used instead of cyan toner matrix particles 1. Furthermore, cyan toners 2 to 42 were prepared in the same manner, except that the types and amounts of silica particles A, silica particles B, and fatty acid metal salts listed in the table were used.

[0314] <Preparation of Black Toner 1> Black toner 1 was prepared in the same manner as yellow toner 1, except that black toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0315] <Preparation of Black Toner 2-42> In the preparation of Black Toner 1, the Black Toner matrix particles listed in the table were used instead of Black Toner matrix particles 1. Furthermore, Black Toners 2 to 42 were prepared in the same manner, except that the types and amounts of silica particles A, silica particles B, and fatty acid metal salts listed in the table were used.

[0316] <Preparation of Red Toner 1> Red toner 1 was prepared in the same manner as yellow toner 1, except that red toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0317] <Preparation of Green Toner 1> Green toner 1 was prepared in the same manner as yellow toner 1, except that green toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0318] <Preparation of Green Toner 2> Green toner 2 was prepared in the same manner as yellow toner 1, except that green toner matrix particles 2 were used instead of yellow toner matrix particles 1.

[0319] <Preparation of Pink Toner 1> Pink toner 1 was prepared in the same manner as yellow toner 1, except that pink toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0320] <Preparation of Orange Toner 1> Orange toner 1 was prepared in the same manner as yellow toner 1, except that orange toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0321] <Preparation of Gold Toner 1> Gold toner 1 was prepared in the same manner as yellow toner 1, except that gold toner matrix particles 2 were used instead of yellow toner matrix particles 1.

[0322] <Preparation of Gold Toner 2-5> In the preparation of gold toner 1, the gold toner matrix particles listed in the table were used instead of gold toner matrix particles 2. Furthermore, gold toners 2 to 5 were prepared in the same manner, except that the types and amounts of silica particles A, silica particles B, and fatty acid metal salts listed in the table were used.

[0323] <Preparation of Silver Toner 1> Silver toner 1 was prepared in the same manner as yellow toner 1, except that silver toner matrix particles 2 were used instead of yellow toner matrix particles 1.

[0324] <Preparation of Silver Toner 2-5> In the preparation of Silver Toner 1, the Silver Toner matrix particles listed in the table were used instead of Silver Toner matrix particles 2. Furthermore, Silver Toners 2 to 5 were prepared in the same manner, except that the types and amounts of silica particles A, silica particles B, and fatty acid metal salts listed in the table were used.

[0325] <Preparation of White Toner 1> White toner 1 was prepared in the same manner as yellow toner 1, except that white toner matrix particles 1 were used instead of yellow toner matrix particles 1.

[0326] <Preparation of White Toner 2> White toner 2 was prepared in the same manner as white toner 1, except that silica particles A and silica particles B were not used.

[0327] <Measuring the moisture content of toner> The moisture content of each toner prepared as described above was measured. The moisture content of the toner is measured using the AQ-300 trace moisture analyzer (manufactured by HIRANUMA Corporation) in the following manner. For the measurement sample, 1 g of toner (including external additives) was left at 10°C and 20% RH for 12 hours, and approximately 0.5 g was accurately weighed and defined as A (g). This sample was heated to 110°C to evaporate the adsorbed water, and titrated for 20 minutes using the above moisture meter to determine the adsorbed water content B (μg) of the sample and the water content C (μg) of the reference sample. From these values, the water content of the sample was calculated using the following formula. Moisture content (mass%)=(BC)×100 / (A×1000000)

[0328] [Table 6]

[0329] [Table 7]

[0330] [Table 8]

[0331] [Table 9]

[0332] [Table 10]

[0333] <Carrier adjustment> <<Preparation of coating resin 1>> To an aqueous solution of 0.3% by mass of sodium benzenesulfonate, cyclohexyl methacrylate monomers and methacrylic acid monomers were added in a mass ratio of (98:2). Coating resin 1 was prepared by adding potassium peroxodisulfate in an amount equivalent to 0.5% by mass of the total amount of each of the above monomers and carrying out emulsion polymerization. The weight-average molecular weight of the above coating resin 1 was measured using a known measuring device and was found to be 500,000.

[0334] <<Preparation of coating resin 2>> Coating resin 2 was prepared in the same manner as coating resin 1, except that cyclohexyl methacrylate / styrene monomers were added in a mass ratio of (50:50) instead of cyclohexyl methacrylate / methacrylic acid.

[0335] <<Preparation of coating resin 3>> Coating resin 3 was prepared in the same manner as coating resin 1, except that methyl methacrylate / styrene monomers were added in a mass ratio of (50:50) instead of cyclohexyl methacrylate / methacrylic acid.

[0336] <<Preparation of coating resin 4>> Coating resin 4 was prepared in the same manner as in the preparation of coating resin 1, except that cyclohexyl methacrylate / methyl methacrylate / methacrylic acid monomers were added in a mass ratio of (87:10:3) instead of cyclohexyl methacrylate / methacrylic acid.

[0337] [Table 11]

[0338] <<Preparation of core material particles>> The volume-average particle size is 33 μm, and the saturation magnetization is 61 A·m. 2 We prepared Mn-Mg-Sr ferrite particles at a concentration of / kg. The volume resistivity of the above ferrite particles is 4.5 × 10⁻⁶. 7 It was Ωcm.

[0339] <<Preparation of Carrier 1>> 100 parts by mass of the "core material particles" prepared above, 3.75 parts by mass of "coating resin 1", and 0.5 parts by mass of melamine particles with a particle size of 60 nm as a resistance modifier were added to a high-speed mixer equipped with stirring blades. The mixture was stirred at 22°C for 15 minutes under conditions where the peripheral speed of the horizontal rotor blades was 8 m / sec. Subsequently, the mixture was heated at 120°C for 50 minutes to produce carrier 1, which has a resin coating layer on the surface of the core material particles, by the action of mechanical impact force (mechanochemical method). The core material exposure area ratio of carrier 1 is 13%, and the volume resistivity is 10 8 It was Ω·cm.

[0340] <<Preparation of Carrier 2>> Carrier 2 was prepared in the same manner as carrier 1, except that coating resin 2 was used instead of coating resin 1. The core material exposure area ratio of carrier 2 was 13%, and the volume resistivity was 10 8 It was Ω·cm.

[0341] <<Preparation of Carrier 3>> Carrier 3 was prepared in the same manner as carrier 1, except that coating resin 3 was used instead of coating resin 1. The core material exposure area ratio of carrier 3 was 13%, and the volume resistivity was 10 8 It was Ω·cm.

[0342] <<Preparation of Carrier 4>> 100 parts by mass of the "core material particles" prepared above, 3.75 parts by mass of "coating resin 4", and 0.5 parts by mass of melamine particles with a particle size of 120 nm as a resistance modifier were added to a high-speed mixer equipped with stirring blades. The mixture was mixed and stirred at 22°C for 15 minutes under conditions where the peripheral speed of the horizontal rotor blades was 8 m / sec. Subsequently, the mixture was heated at 120°C for 50 minutes to produce carrier 4, which has a resin coating layer on the surface of the core material particles, by the action of mechanical impact force (mechanochemical method). The core material exposure ratio of carrier 4 is 13%, and the volume resistivity is 10 8 It was Ω·cm.

[0343] [Table 12]

[0344] <Preparation of Yellow Developer 1> Carrier 1 and yellow toner 1 were placed in a V-type mixer in the following quantities and mixed for 5 minutes under normal temperature and humidity conditions to prepare yellow developer 1. Carrier 1: 100 mass unit • Yellow toner 1:6 mass parts

[0345] <Preparation of yellow developer 2-42> Yellow developers 2 to 42 were prepared in the same manner as in the preparation of yellow developer 1, except that yellow toners 2 to 42 were used instead of yellow toner 1.

[0346] <Preparation of yellow developer 43-45> Yellow developers 43 to 45 were prepared in the same manner as in the preparation of yellow developer 1, except that yellow toner 18 was used instead of yellow toner 1, and carriers 2 to 4 were used instead of carrier 1.

[0347] <Preparation of Magenta Developer 1> Magenta developer 1 was prepared in the same manner as yellow developer 1, except that magenta toner 1 was used instead of yellow toner 1.

[0348] <Preparation of magenta developer 2-42> Magenta developers 2 to 42 were prepared in the same manner as magenta developer 1, except that magenta toners 2 to 42 were used instead of magenta toner 1.

[0349] <Preparation of magenta developer 43-45> Magenta developers 43 to 45 were prepared in the same manner as magenta developer 1, except that magenta toner 18 was used instead of magenta toner 1, and carriers 2 to 4 were used instead of carrier 1.

[0350] <Preparation of Cyanide Developer 1> The cyan developer 1 was prepared in the same manner as the yellow developer 1, except that cyan toner 1 was used instead of yellow toner 1.

[0351] <Preparation of cyanide developer 2-42> Cyanide developers 2 to 42 were prepared in the same manner as in the preparation of cyanide developer 1, except that cyanide toners 2 to 42 were used instead of cyanide toner 1.

[0352] <Preparation of cyanide developer 43-45> Cyanide developers 43 to 45 were prepared in the same manner as in the preparation of cyanide developer 1, except that cyanide toner 18 was used instead of cyanide toner 1, and carriers 2 to 4 were used instead of carrier 1.

[0353] <Preparation of Black Developer 1> Black developer 1 was prepared in the same manner as yellow developer 1, except that black toner 1 was used instead of yellow toner 1.

[0354] <Preparation of Black Developer 2-42> Black image agents 2-42 were prepared in the same manner as in the preparation of black developer 1, except that black toners 2-42 were used instead of black toner 1.

[0355] <Preparation of black developer 43-45> Black developers 43 to 45 were prepared in the same manner as in the preparation of black developer 1, except that black toner 18 was used instead of black toner 1, and carriers 2 to 4 were used instead of carrier 1.

[0356] <Preparation of Red Developer 1> Red developer 1 was prepared in the same manner as yellow developer 1, except that red toner 1 was used instead of yellow toner 1.

[0357] <Preparation of Green Developers 1 and 2> Green developers 1 and 2 were prepared in the same manner as yellow developer 1, except that green toners 1 and 2 were used instead of yellow toner 1.

[0358] <Preparation of Pink Developer 2> Pink developer 1 was prepared in the same manner as yellow developer 1, except that pink toner 1 was used instead of yellow toner 1.

[0359] Orange developer 1 was prepared in the same manner as yellow developer 1, except that orange toner 1 was used instead of yellow toner 1.

[0360] <Preparation of gold developers 1-5> Gold developers 1 to 5 were prepared in the same manner as yellow developer 1, except that gold toners 1 to 5 were used instead of yellow toner 1.

[0361] <Preparation of Silver Developers 1-5> Silver developers 1 to 5 were prepared in the same manner as yellow developer 1, except that silver toners 1 to 5 were used instead of yellow toner 1.

[0362] <Preparation of white developer 1 and 2> White developers 1 and 2 were prepared in the same manner as in the preparation of yellow developer 1, except that white developers 1 and 2 were used instead of yellow toner 1.

[0363] [Table 13]

[0364] [Table 14]

[0365] [Table 15]

[0366] [Table 16]

[0367] [Table 17]

[0368] <Preparing Toner Set 1> A toner set 1 was prepared, consisting of 1 yellow developer, 1 magenta developer, 1 cyan developer, 1 black developer, 5 gold developers, and 5 silver developers.

[0369] <Preparing toner sets 2-60> Using the developer listed in the table, we prepared toner sets 2 through 60.

[0370] [Table 18]

[0371] <Image forming apparatus 1> A modified full-color printing press (bizhub PRESS C1070; Konica Minolta, Inc.) was used. The lubricant stock provided in the lubricant application unit 416 shown in Figure 3 was the zinc stearate lubricant rod 1. In addition, the normal fuser was removed and replaced with a fixing system as shown in Figure 2, which included a non-contact heating fixing unit 160 using far-infrared irradiation and a pressurized fixing unit 170 using low pressure (60 kPa). The peak wavelength of the far-infrared irradiation in this fixing system was 5.0 μm, and the line velocity when passing through the fixing system was 750 mm / sec.

[0372] <Image forming apparatus 2> Image forming apparatus 2 is an image forming apparatus 1 in which the lubricant application unit 416 has been removed.

[0373] <Image forming apparatus 3> Image forming apparatus 3 is an image forming apparatus 1 in which the pressure fixing section 170, which includes the pressure roller 171 and fixing roller 172 shown in Figure 2, has been removed.

[0374] [Table 19]

[0375] <Example 1> Various evaluations were performed using the toner set 1 in the image forming apparatus 1.

[0376] <Examples 2-58, Comparative Examples 1-4> Various evaluations were conducted using the toner sets and image forming apparatus listed in the table.

[0377] [evaluation] <Bending resistance> At low temperature and low humidity (temperature 10℃, humidity 20%), A3 size coated paper "OK ​​Topcoat+ (157g / m²)" 2 On the (Oji Paper Co., Ltd.) sheet, the amount of toner adhering to each color was 0.3 mg / cm². 2 The process was adjusted to create an image in which all colors were superimposed. This image was folded using a folding machine, and then air at 0.35 MPa was blown onto it. The state of the folds was observed visually and under a microscope and evaluated on a 5-point scale, with ranks A to D being considered acceptable. (standard) Rank A: No peeling at the folds, as observed visually and under a microscope. Rank B: Some peeling occurs along the folds during microscopic observation, but it is not visible to the naked eye. Rank C: Some peeling is visible along the folds. Rank D: Thin, linear peeling observed along the folds. Rank E: Visible thick peeling along the folds, or large peeling as shown in the image.

[0378] <Abrasion resistance> Image density was measured for the solid image area using a Macbeth RD-918 reflectance densitometer. Image density was expressed as relative density to white paper. The measurement area was made of plain-weave bleached cotton at 22 g / cm³. 2 The image was rubbed 14 times under a load. After rubbing, the image density of the measurement area was measured, and the density ratio before and after rubbing was defined as the fixation rate. Fixation rate (%) = {(Image density after rubbing) / (Image density before rubbing)} × 100 If the fixation rate is 90% or higher, there will be no color transfer to the edges of the image, and it will be considered to be at a passing level. At low temperature and low humidity (temperature 10℃, humidity 20%), A3 size coated paper "OK ​​Topcoat+ (157g / m²)" 2 On the (Oji Paper Co., Ltd.) sheet, the amount of toner adhering to each color was 0.3 mg / cm². 2 The process was adjusted to create an image with all colors superimposed. The resulting fixed image was then placed on top of unused paper and pressed at 0.980 kPa / cm². 2 The load was applied and the paper was moved back and forth 10 times. Afterwards, the soiling of the unused copy paper was visually observed, and the abrasion resistance was evaluated as follows. Ranks A to C were considered acceptable. (standard) Rank A: The paper is noticeably soiled, with an unacceptable level of staining. Rank B: Paper stains are observed, but the level of staining is acceptable. Rank C: There are very slight stains, but they are barely noticeable. Rank D: No visible dirt or stains.

[0379] <Paper deformation> The paper deformation was evaluated at low temperature and low humidity (temperature 10°C, humidity 20%) on A3 size coated paper "OK ​​Topcoat+" (104.7g / m²). 2 The image was formed on a sheet of paper (manufactured by Oji Paper Co., Ltd.). The amount of toner deposited for each color was 0.3 mg / cm². 2 The process was adjusted to achieve this result, and 50 images were created by overlaying all colors. The presence or absence of localized deformation was then visually evaluated. Ranks A to C were considered acceptable. (evaluation) Rank A: No localized deformations observed, no problems. Rank B: Minor deformations that do not pose a practical problem are observed in 1-2 images. Rank C: Minor deformations that do not pose a practical problem are observed in 3 to 5 images. Rank D: Minor deformation is observed in 6 or more images, or deformation at a level that is practically problematic is present in 1 or more images.

[0380] <Blister pack> The blister pack was evaluated under low temperature and low humidity conditions (temperature 10°C, humidity 20%) on A3 size coated paper "OK ​​Topcoat+ (157g / m²)". 2 The image was formed on a sheet of paper (manufactured by Oji Paper Co., Ltd.). The amount of toner deposited for each color was 0.3 mg / cm². 2 The process was adjusted to create an image with all colors superimposed. This image was then visually and microscopically inspected for holes approximately 0.1 to 0.5 mm in diameter, i.e., toner blisters, and evaluated. Ranks A to C were considered acceptable. (standard) A: Observed under a microscope, 4 cm 2 There are 0-2 toner blisters per unit, but they are barely noticeable to the naked eye unless you look very closely, so there are no practical problems. B: Observed under a microscope, 4 cm 2 There are 3 to 5 toner blisters per unit, but they are barely noticeable unless you look very closely, so there are no practical problems. C: Observed under a microscope, 4 cm 2 There are 6-8 toner blisters per unit, but they are barely noticeable to the naked eye unless you look very closely, so there are no practical problems. D: Observed under a microscope, 4cm 2 There are 9 or more clearly visible toner blisters per unit, which poses a practical problem.

[0381] <Cleaning properties> Under normal temperature and humidity conditions (NN environment; 23℃, 50%RH), A3 size coated paper "OK ​​Topcoat+ (157g / m²)" 2 The image was formed on a sheet of paper (manufactured by Oji Paper Co., Ltd.). The amount of toner deposited for each color was 0.3 mg / cm². 2 The process was adjusted accordingly, and a durability test was conducted involving 30,000 prints on an image chart with 20% image density using all colors from the toner set. After the durability test, the surface of the photoreceptor was observed under a microscope, and the total number of developer-derived deposits was measured in three 20mm x 40mm fields of view: back, center, and front. The measurement results were evaluated according to the following criteria, and ranks A to C were judged to be of acceptable quality. (standard) A: No attached substances B: 1 to less than 6 attached objects C: 6 or more but less than 11 attached objects D: 11 or more attached objects

[0382] <Transferability> Under normal temperature and humidity conditions (NN environment; 23℃, 50%RH), A3 size coated paper "OK ​​Topcoat+ (157g / m²)" 2 Halftone images of each color were formed on a sheet of paper (manufactured by Oji Paper Co., Ltd.). The image density of this image was measured at a total of five points along the axis of the photoreceptor: the center, the edges, and two points midway between the center and the edges. The variation in image density was then determined. The edges are located 2 cm from each end. Image density was measured using a Macbeth RD-918 densitometer (manufactured by Macbeth). Image density variability was calculated by determining the difference between the maximum and minimum values ​​among five measured points, and then expressing this difference as a percentage relative to the arithmetic mean of the five points. Image density variability was evaluated based on the following criteria. Ranks A through C were considered acceptable. (standard) A: The variation in image density is less than 10% for all colors. B: There are colors with image density variations of 10% or more and less than 15%. C: There are colors with image density variations of 15% or more and less than 20%. D: There is a variation in image density of 20% or more in some colors.

[0383] [Table 20]

[0384] [Table 21]

[0385] As shown in the results above, the image forming method of the present invention is superior to the comparative example in terms of bending resistance, abrasion resistance, cleanability, and transferability, and can prevent paper deformation and blistering. [Explanation of Symbols]

[0386] 1. Image forming apparatus 4, 41T, 42T, 4Y, 4M, 4C, 4K Photoconductor Drum 5, 51T, 52T, 5Y, 5M, 5C, 5K Image Forming Units 160 Non-contact heating and fixing section 170 Pressurized fixing section 170 412 Developing equipment 414 Charging device 415 Drum cleaning device 416 Lubricant application unit

Claims

1. An image forming method comprising the steps of: developing an electrostatic latent image formed on an electrophotographic photoreceptor with an electrostatic image developing toner; transferring the developed toner image to a transfer material; and fixing the transferred toner image, The fixing process involves fixing the toner image by non-contact heating, The electrostatic image developing toner satisfies the following conditions (I) and (II): Condition (I): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the external additive contains silica particles A having a primary particle number average size in the range of 55 to 400 nm. Condition (II): The electrostatic image developing toner of at least one color comprises toner matrix particles and an external additive, wherein the toner matrix particles contain metal particles or metal oxide particles. A method for forming an image characterized by the following features.

2. The metal particles or metal oxide particles are aluminum particles, titanium oxide particles, or alumina particles. The image forming method according to feature 1.

3. The aforementioned fixing process further fixes the toner image by applying pressure. The image forming method according to feature 1.

4. The amount of moisture in the electrostatic image developing toner containing the silica particles A is within the range of 0.05 to 0.90% by mass when left for 48 hours in an environment with a temperature of 10°C and a relative humidity of 20%. The image forming method according to feature 1.

5. The process includes applying a lubricant containing a fatty acid metal salt to the surface of the electrophotographic photoreceptor. The image forming method according to feature 1.

6. The external additive of the electrostatic image developing toner of at least one color contains a fatty acid metal salt. The image forming method according to feature 1.

7. The fatty acid metal salt contains either zinc stearate or calcium stearate. The image forming method according to claim 5 or 6.

8. The melting point of the fatty acid metal salt is 120°C or higher. The image forming method according to claim 5 or 6.

9. The mass ratio of the fatty acid metal salt to the silica particles A is within the range of 0.1 to 5.

0. The image forming method according to feature 6.

10. The toner matrix particles contain a crystalline resin. The image forming method according to feature 1.

11. The aforementioned external additive contains silica particles B having a primary particle number average particle size in the range of 20 to 40 nm. The image forming method according to feature 1.

12. The aforementioned non-contact heating is heating using electromagnetic waves having a peak wavelength in the range of 1 to 10 μm. The image forming method according to feature 1.

13. The aforementioned fixing process involves fixing the media on which the unfixed image has been formed while transporting it at a linear speed of 300 to 800 mm / s. The image forming method according to feature 1,

14. The image is output using a toner set. Of the toner sets mentioned above, the electrostatic image developing toners that satisfy condition (I) are four colors: yellow toner, magenta toner, cyan toner, and black toner. The electrostatic image developing toner that satisfies the above condition (II) is at least one of white toner, gold toner, and silver toner. The image forming method according to feature 1.

15. The electrostatic image developing toner that satisfies the above condition (I) further comprises pink toner or green toner. The image forming method according to feature 14.

Images