toner

Abstract

To provide a toner excellent in low-temperature fixability, hot offset resistance, and bending resistance.SOLUTION: A toner has toner particles containing binder resins and silica fine particles. A tetrahydrofuran soluble matter of the toner contains 50 mass% or more of a component having a molecular weight of 4000 to 50000. The toner particles contain the silica fine particles in a specific internal region and have a peak corresponding to Si of D1 unit, a peak corresponding to Si of D2 unit, and a peak corresponding to Si of Q unit in DD / MAS measurement of solid 29Si-NMR of tetrahydrofuran insoluble matter of the toner particle. Each peak area satisfies a specific relationship.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to toner used in electrophotography, electrostatic recording, electrostatographic printing, and toner jet methods.

Background Art

[0002] In recent years, full-color copiers using electrophotography have become widespread and are also starting to be applied to the printing market. In the printing market, high speed, high image quality, and high productivity are required while accommodating a wide range of media (paper types). For example, media isochronism is required such that printing can continue without changing the process speed according to the paper type or the heating set temperature of the fuser even when the paper type is changed from thick paper to thin paper.

[0003] In order to achieve excellent media isochronism, there is a demand for toner that can properly complete fixing in a wide temperature range from low temperature to high temperature. Specifically, studies have been conducted on toner that can be quickly softened at low temperatures while maintaining a viscosity that does not cause hot offset at high temperatures. For example, Patent Document 1 discloses adding fine particles to toner in order to complete fixing at a wide range of temperatures.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when fine particles are added to the toner, the interface between the binder resin and the fine particles increases, resulting in the fixed image being prone to cracking at the interface and the flex resistance may decrease. To address this problem, the flex resistance can be improved by using a high molecular weight resin with a large amount of cross-linking components as the binder resin. However, in this case, it has been found that the glass transition point of the toner becomes high, resulting in insufficient low-temperature fixing performance.

[0006] The present disclosure provides a toner that can be properly fixed in a wide temperature range from low to high temperatures and is simultaneously excellent in flex resistance. Specifically, it provides a toner excellent in low-temperature fixing performance, hot offset resistance, and flex resistance.

Means for Solving the Problems

[0007] A toner having toner particles containing a binder resin and silica fine particles, The tetrahydrofuran-soluble component obtained by dissolving the toner in tetrahydrofuran contains 50% by mass or more of components having a molecular weight of 4000 to 50000 based on the mass of the tetrahydrofuran-soluble component, The toner particles contain the silica fine particles in a region 0.3 μm or more inside from the surface, A solid using the tetrahydrofuran-insoluble component obtained by dissolving the toner particles in tetrahydrofuran as a sample In the DD / MAS measurement of Si-NMR, Si in the structure represented by the following formula (1) <00神仙道0002>a peak corresponding to the silicon atom represented by, Si in the structure represented by the following formula (2) <00神仙道0003>a peak corresponding to the silicon atom represented by, and Si in the structure represented by the following formula (3) <00神仙道0004>has a peak corresponding to the silicon atom represented by, <00神仙道0006>The area of the peak corresponding to the silicon atom represented by the Si <00神仙道0005>is defined as SD1, the area of the peak corresponding to the silicon atom represented by the Si <00神仙道0006>is defined as SD2, and the Si <00神仙道0007>When the area of the peak corresponding to the silicon atom represented by is <00神仙道0007>designated as SQ, <00神仙道0008>A toner characterized in that SD1, SD2, and SQ satisfy the following formulas (a) and (b). 0.050≦(SD1+SD2) / SQ (a) (SD1+SD2) / SD1≦25.0 (b) [ka] (In formulas (1) and (2), R independently represents a hydrogen atom, a methyl group, or an ethyl group.) [Effects of the Invention]

[0008] This disclosure makes it possible to provide a toner with excellent low-temperature fixation properties, hot offset resistance, and bending resistance. [Modes for carrying out the invention]

[0009] In this disclosure, descriptions indicating numerical ranges such as "XX or more and YY or less" or "XX to YY" mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way. Furthermore, a monomer unit refers to the reacted form of monomer substances in a polymer.

[0010] The inventors of this invention have diligently studied to provide a toner with excellent low-temperature fixing properties, hot offset resistance, and bending resistance. As a result, they have found that the above problems can be solved with the following toner.

[0011] A toner having toner particles containing a binder resin and silica fine particles, The tetrahydrofuran-soluble components obtained by dissolving the toner in tetrahydrofuran contain 50% by mass or more of components with a molecular weight of 4000 to 50000, based on the mass of the tetrahydrofuran-soluble components. The toner particles contain the silica fine particles in a region 0.3 μm or more inward from the surface. The tetrahydrofuran-insoluble components obtained by dissolving the toner particles in tetrahydrofuran are A solid used as a sample 29 In the DD / MAS measurement of Si-NMR, Si in the structure shown by the following formula (1) a The peak corresponding to the silicon atom represented by, Si in the structure shown by the following formula (2) b The peak corresponding to the silicon atom represented by, and Si in the structure shown by the following formula (3) c has a peak corresponding to the silicon atom represented by, Regarding this Si a Let the area of the peak corresponding to the silicon atom represented by be SD1, and regarding this Si b Let the area of the peak corresponding to the silicon atom represented by be SD2, and regarding this Si c when the area of the peak corresponding to the silicon atom represented by is SQ, A toner characterized in that the SD1, the SD2, and the SQ satisfy the following formulas (a) and (b). 0.050 ≦ (SD1 + SD2) / SQ ··· (a) (SD1 + SD2) / SD1 ≦ 25.0 ··· (b)

Chemical formula

[0012] The reason for obtaining the above effect is considered as follows. In order to improve the low-temperature fixing property of the toner, it is necessary to lower the melt viscosity of the toner. To lower the melt viscosity of the toner, a means of reducing the molecular weight of the binder resin contained in the toner particles can be considered. However, when the molecular weight of the binder resin is reduced, the interaction between molecular chains derived from the entanglement of the molecular chains of the binder resins decreases, resulting in a decrease in the elasticity of the toner and a decrease in the hot offset resistance.

[0013] One method to increase the elasticity of toner is to add inorganic microparticles to the toner particles to induce a filler effect. However, when inorganic microparticles are added to toner particles, the number of interfaces between the inorganic microparticles and the binder resin increases, making the fixed image more prone to cracking at the interfaces, thus reducing the bending resistance of the printed material.

[0014] As a result of diligent research, the inventors have found a binder resin containing 50% by mass or more of a component with a molecular weight of 4000 to 50000, 29 In DD / MAS measurements of Si-NMR, as shown in equation (1) Si in the structure a Let SD1 be the area of ​​the peak corresponding to the silicon atom shown, and the Si in the structure shown in equation (2) b Let SD2 be the area of ​​the peak corresponding to the silicon atom shown, and the Si in the structure shown in equation (3) c We have found that by incorporating silica fine particles in toner particles in which SD1, SD2, and SQ satisfy the following formulas (a) and (b), when the area of ​​the peak corresponding to the silicon atom shown is denoted as SQ, a toner exhibiting unprecedented low-temperature fixation, hot offset resistance, and bending resistance can be obtained. 0.050≦(SD1+SD2) / SQ (a) (SD1+SD2) / SD1≦25.0 (b)

[0015] The fact that SD1, SD2, and SQ of the silica nanoparticles satisfy formulas (a) and (b) above indicates the presence of a compound having siloxane bonds on the surface of the silica nanoparticles. The presence of the siloxane-bonded compound on the surface of the silica nanoparticles allows the binder resin and the silica nanoparticle surface to interact within the toner particles when the silica nanoparticles are added internally. As a result, cracking of the fixed image is suppressed, and bending resistance is improved. While the siloxane-bonded compound only needs to be present on the surface of the silica nanoparticles, it is more preferable that it is immobilized.

[0016] Silica microparticles are solid after washing with tetrahydrofuran (THF). 29In Si-NMR DD / MAS measurements, the following condition is met: 0.050 ≤ (SD1 + SD2) / SQ (Equation (a)). The value of (SD1 + SD2) / SQ represents the amount of siloxane-bonded compound present on the surface of the silica nanoparticles. This compound is a polar compound of the unit Si of Equation (1). a and the unit Si in formula (2) b Because it has this property, the binder resin in the toner particles and the compound can interact. When (SD1+SD2) / SQ is 0.050 or more, a certain amount or more of the compound is present on the surface of the silica fine particles. As a result, the interaction between the binder resin and the compound becomes stronger, improving bending resistance and hot offset resistance without reducing low-temperature fixability.

[0017] Silica microparticles are solid after washing with tetrahydrofuran (THF). 29 In Si-NMR DD / MAS measurements, the condition (SD1+SD2) / SD1 ≤ 25.0 (equation (b)) is satisfied. The value of (SD1+SD2) / SD1 represents the length of the siloxane bond molecular chain present on the surface of the silica nanoparticles. If the siloxane bond molecular chain present on the surface of the silica nanoparticles is too long, the interaction with the polar groups of the binder resin is inhibited, and the low-temperature fixation performance decreases. By setting (SD1+SD2) / SD1 to 25.0 or less, the binder resin and the compound having siloxane bonds... It can interact efficiently. As a result, it can achieve both low-temperature fixation and bending resistance.

[0018] The silica microparticles contained within the toner particles have a structure represented by, for example, the following formula (A). The structure represented by the following formula (A) can be obtained, for example, by treating the surface of the silica microparticle substrate with a treatment agent having siloxane bonds. [ka] (R in equation (A)) 1 , R 2 , R 3 , R 4 , R 5 Each of these independently represents a hydrogen atom or a number of carbon atoms. It represents one or two alkyl groups, and n is an integer of 0 or more (preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 to 2).

[0019] In order to achieve the effects of this disclosure, it is preferable that compounds having siloxane bonds present on the surface of the silica microparticles interact with the binder resin at a molecular level. For this purpose, it is preferable that the binder resin be mixed with the silica microparticles in a molten or dissolved state. At this time, if 50% or more by mass of components with a molecular weight of 4,000 to 50,000 are present in the THF-soluble components obtained by dissolving toner in THF, the mobility of the binder resin increases, allowing the polar portion of the binder resin and the polar portion of the siloxane portion on the surface of the silica microparticles to interact efficiently. As a result, resistance to hot offset and resistance to bending are improved. For the reasons mentioned above, we have obtained a toner with excellent low-temperature fixing properties, hot offset resistance, and bending resistance.

[0020] The silica microparticles used in the toner of this disclosure are described below. Silica microparticles are the solid components of the tetrahydrofuran-insoluble toner particles. 29 In DD / MAS measurements of Si-NMR, the Si in the structure shown in equation (1) a For silicon atoms shown as Corresponding peaks, Si in the structure shown in equation (2) b The peaks corresponding to silicon atoms shown, and the Si in the structure shown in equation (3). c It has a peak corresponding to the silicon atom shown by . Note that the Si in the structure shown in formula (1) a The silicon atom shown in equation (2) is a silicon atom having a so-called D1 unit structure, and the structure shown in equation (2) is Si b The silicon atom shown in equation (3) is a silicon atom having a so-called D2 unit structure, and is the Si atom in the structure shown in equation (3). c The silicon atom shown is a silicon atom that has a so-called Q unit structure. [ka] (In formulas (1) and (2), R independently represents a hydrogen atom, a methyl group, or an ethyl group.)

[0021] Si in the structure shown in equation (1) a The area of ​​the peak corresponding to the silicon atom shown is S. When D1 is used, the value of SD1 is preferably 0.10 or more and 7.00 or less, more preferably 1.00 or more and 6.00 or less, and even more preferably 2.00 or more and 5.00 or less. Si in the structure shown in equation (2) b When the area of ​​the peak corresponding to the silicon atom shown is defined as SD2, the value of SD2 is preferably 3.00 or more and 40.00 or less, more preferably 4.00 or more and 20.00 or less, and even more preferably 5.00 or more and 10.00 or less. Si in the structure shown in equation (3) c When the area of ​​the peak corresponding to the silicon atom shown is denoted as SQ, the value of SQ is preferably 100.00 to 250.00, more preferably 130.00 to 230.00, and even more preferably 150.00 to 200.00. When the value is within the above range, a toner with excellent low-temperature fixability, hot offset resistance, and bending resistance can be obtained.

[0022] A value of (SD1+SD2) / SQ of 0.050 or higher indicates that a certain amount or more of a compound containing siloxane bonds is present on the surface of the silica nanoparticles. Therefore, when silica nanoparticles are incorporated into toner particles, the binder resin and the silica nanoparticles can interact efficiently. As a result, bending resistance and hot offset resistance can be improved without reducing low-temperature fixation performance.

[0023] The range of (SD1 + SD2) / SQ is preferably 0.050 or more and 0.200 or less, more preferably 0.050 or more and 0.150 or less, and even more preferably 0.050 or more and 0.090 or less. When this range is satisfied, excellent low-temperature fixing properties, hot offset resistance, and bending resistance can be achieved simultaneously. The value of (SD1 + SD2) / SQ can be controlled by changing the type and amount of the treating agent having a siloxane bond, the treatment time, and the treatment temperature when performing surface treatment on the surface of the silica particle substrate. Specifically, for example, the value can be increased by lowering the treatment temperature. On the other hand, the value can be decreased by raising the treatment temperature.

[0024] On the other hand, that the value of (SD1 + SD2) / SD1 is 25.0 or less indicates that the molecular chain of the siloxane bond present on the surface of the silica particles is not too long and the interaction with the binder resin is not inhibited. As a result, the binder resin and the silica particles can interact efficiently, and both low-temperature fixing properties and bending resistance can be achieved.

[0025] The range of (SD1 + SD2) / SD1 is preferably 1.0 or more and 25.0 or less, more preferably 1.0 or more and 10.0 or less, even more preferably 1.0 or more and 5.0 or less, even more preferably 1.5 or more and 4.5 or less, particularly preferably 2.0 or more and 4.0 or less, and especially preferably 2.0 or more and 3.0 or less. When this range is satisfied, the interaction between the binder resin and the silica particles is not inhibited, so that both bending resistance, hot offset resistance, and low-temperature fixing properties can be achieved. The value of (SD1 + SD2) / SD1 can be controlled by changing the type and amount of the treating agent having a siloxane bond, the treatment time, and the treatment temperature when performing the surface treatment described below on the surface of the silica particle substrate. Specifically, for example, the value can be increased by lowering the treatment temperature. On the other hand, the value can be decreased by raising the treatment temperature.

[0026] <NMR measurement method> As a pretreatment for NMR measurement, silica microparticles are separated from toner particles using the following method. (Method for separating silica microparticles from toner particles) 2 50 mL vials of 10% by mass aqueous solution of "Contaminon N" (a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder). Weigh out 0g and mix it with 1g of toner. The toner is placed in an Iwaki Sangyo Co., Ltd. "KM Shaker" (model: V.SX), and the speed is set to 50 and shaken for 30 seconds. This causes external additives, such as added inorganic microparticles, to migrate from the surface of the toner particles to the aqueous solution. Then, in the case of magnetic toner containing magnetic material, the toner particles are restrained using a neodymium magnet, and the external additives that have migrated to the supernatant are separated. The settled toner particles are then dried in a vacuum (40°C / 24 hours) to dry them out and recovered.

[0027] In the case of non-magnetic toner, the toner and the external additives that have migrated to the supernatant liquid are separated using a centrifuge (H-9R; manufactured by Kokusan Co., Ltd.) (1000 rpm for 5 minutes). The external additives were removed from the surface of the toner particles by the above procedure. The recovered toner particles were observed using an electron microscope (SEM) to confirm that the external additives attached to the surface of the toner particles had been completely removed. If any external additives remained on the surface of the toner particles, they were dispersed again in water and shaken. Next, toner particles from which surface additives had been removed were dissolved in THF and left overnight. After that, silica microparticles contained inside the toner particles were recovered using a far-sighted separator, dried, and prepared as NMR measurement samples.

[0028] (solid 29 (Method for measuring SiNMR) solid 29 The specific measurement conditions for Si-NMR are as follows: Equipment: JNM-ECA400 (JEOL RESONANCE) Calibration: Tetramethylsilane (TMS) at 0 ppm Temperature: room temperature Measurement method: DD / MAS method 29 Si 45° Sample tube: Zirconia 8.0 mmφ Sample: A test tube filled with silica particles in powder form. Sample rotation speed: 6kHz Relaxation delay: 90 seconds Scan: 5640 In the NMR spectrum obtained by the above measurements, by separating the peak corresponding to the siloxane chain appearing around -20 ppm from the peak corresponding to the silica nanoparticle substrate appearing around -110 ppm, the Si in the structure shown by equation (1) can be identified. a , Si in the structure shown in equation (2) b , and Si in the structure shown in formula (3) c Obtain the respective peak areas SD1, SD2, and SQ. Peak separation is performed using the following procedure.

[0029] (Peak separation method) Peak separation is performed by extracting the NMR spectrum data obtained by the method described above into CSV format and analyzing it. Peak separation can be performed using commercially available software or a program created in-house, following the procedure described below. Si in the structure shown in equation (1) a The peak corresponding to this is at -18.2 ppm, where Si in the structure shown in equation (2) is located. b The peak corresponding to this is at -21.0 ppm, where Si in the structure shown in equation (3) is located. c The peak positions are fixed at -110.0 ppm, and peak separation is performed using the Voigt function.

[0030] Silica microparticles contained within toner particles can be obtained, for example, by treating the surface of a silica microparticle substrate with a treatment agent having siloxane bonds. The treatment agent having siloxane bonds is not particularly limited, and known materials can be used.

[0031] Examples of treatment agents having siloxane bonds include dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, and alkyl-modified silicone oil. Examples of silicone oils include yl, chloroalkyl-modified silicone oil, chlorophenyl-modified silicone oil, fatty acid-modified silicone oil, polyether-modified silicone oil, alkoxy-modified silicone oil, carbinol-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, and terminal-reactive silicone oil. Preferably used treatment agents are cyclic siloxanes such as hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, pentamethylcyclopentasiloxane, and dimethyldichlorosilane. The cyclic siloxanes may have substituents on some of the methyl groups bonded to the silicon atom. From the viewpoint of uniformly coating the surface of the silica nanoparticle substrate with the molecular structure defined in this disclosure, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, pentamethylcyclopentasiloxane, and dimethyldichlorosilane are more preferred, and octamethylcyclotetrasiloxane is particularly preferred.

[0032] The amount of the treatment agent having a siloxane bond is preferably 40 to 250 parts by mass, and more preferably 70 to 180 parts by mass, per 100 parts by mass of the silica fine particle substrate. In particular, when surface treatment is performed by contacting the silica fine particle substrate with a cyclic siloxane using steam, adding 100 parts by mass or more of the siloxane to the silica fine particle substrate allows for uniform surface treatment of the silica fine particle substrate, making it easier to control the value of (SD1 + SD2) / SQ.

[0033] In this disclosure, when silica nanoparticles are surface-treated with a treatment agent having siloxane bonds or a surface treatment agent such as silicone oil, the portion derived from the surface treatment agent is also referred to as silica nanoparticles. Furthermore, silica nanoparticles before surface treatment are also referred to as silica nanoparticle substrates. Surface treatment of silica microparticle substrates is performed, for example, by contacting the silica microparticle substrate with a treatment agent having siloxane bonds. From the viewpoint of uniformly distributing compounds having siloxane bonds on the surface of the silica microparticle substrate, it is preferable to contact the silica microparticle substrate with the treatment agent in a dry manner. Methods for dry contact include, for example, contacting the silica microparticle substrate with the vapor of the treatment agent, or spraying the undiluted solution of the treatment agent or a diluted solution with various solvents into contact with the silica microparticle substrate.

[0034] To efficiently perform surface treatment, it is preferable to bring the treatment agent into contact with the silica microparticle substrate while heating under an inert gas atmosphere such as a nitrogen atmosphere. The heating temperature varies depending on the reactivity of the treatment agent used, but is preferably 150 to 380°C, more preferably 300 to 350°C. The treatment time also varies depending on the heating temperature and the reactivity of the treatment agent used, but is preferably 5 to 300 minutes, more preferably 30 to 200 minutes. Surface treatment temperature and treatment time within the above ranges are preferable from the viewpoint of allowing the treatment agent to react sufficiently with the silica microparticle substrate and from the viewpoint of production efficiency. Furthermore, when performing surface treatment under reduced pressure, it is preferable to set the pressure due to the vapor of the surface treatment agent in the container to 0.1 Pa or more and 100 Pa or less, and more preferably 1.0 Pa or more and 10 Pa or less. By setting the pressure within this range, the frequency of contact between the vapor molecules of the surface treatment agent is reduced, suppressing chemical reactions between the surface treatment agents and allowing the chemical reaction between the surface treatment agent in contact with the surface of the silica microparticle substrate to proceed preferentially. Furthermore, reaction byproducts generated by the chemical reaction between the silica microparticle substrate and the surface treatment agent can be easily removed from the vicinity of the silica microparticle surface, allowing the surface treatment agent to come into closer contact with the surface of the silica microparticle substrate, and enabling more uniform surface treatment of the silica microparticle substrate. Furthermore, when performing surface treatment under reduced pressure, it is preferable to heat the silica microparticle substrate under reduced pressure before bringing the surface treatment agent into contact with the surface of the silica microparticle substrate, thereby performing a degassing treatment to remove moisture and other substances adsorbed on the surface of the silica microparticle substrate. This makes it easier for the surface treatment agent to come into contact with the surface of the silica microparticles, allowing for more uniform surface treatment of the silica microparticle substrate. From this perspective, it is also preferable to repeatedly perform degassing treatment and surface treatment of silica fine particles with a surface treatment agent. By the method described above, a compound having siloxane bonds can be present on the surface of a silica nanoparticle substrate, making it possible to form the siloxane chains, which are a feature of this disclosure, on the surface of the silica nanoparticles after surface treatment.

[0035] Known materials can be used as the silica nanoparticle substrate, which is the silica nanoparticle before surface treatment. Examples include silicon compounds, especially silicon halides, generally silicon chlorides, fumed silica usually produced by burning purified silicon tetrachloride in an oxyhydrogen flame, wet silica produced from water glass, sol-gel silica particles obtained by a wet process, gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, molten silica particles obtained by a gas-phase process, and deflagration silica particles.

[0036] The number-average particle size of the silica nanoparticles is preferably 5 to 300 nm, and more preferably 20 to 150 nm. This allows the silica nanoparticles to interact appropriately with the binder resin, resulting in better low-temperature fixation, hot offset resistance, and bending resistance.

[0037] <Method for measuring the number-average particle size of primary silica microparticles> Toner particles dispersed in a water-soluble resin were placed in a cryomicrotome (Leica ULTRACUT UCT). The apparatus was cooled to -80°C with liquid nitrogen, freezing the water-soluble resin containing the dispersed toner particles. The frozen water-soluble resin was trimmed using a glass knife to create a cutting surface shape with a width of 0.1 mm and a length of 0.2 mm. Next, ultrathin sections (thickness setting: 70 nm) of toner particles containing water-soluble resin were prepared using a diamond knife and moved onto the observation grid mesh of a transmission electron microscope (TEM) using an eyelash probe. After the ultrathin sections of toner particles containing water-soluble resin were returned to room temperature, the water-soluble resin was dissolved in pure water to prepare the TEM observation sample. The sample was observed using a transmission electron microscope H-7500 (Hitachi Corporation) at an acceleration voltage of 100kV, and magnified images of the cross-section of the toner particles were taken. The magnification of the magnified images was set to 20,000x. To determine the number-average diameter of the primary particles of silica nanoparticles using TEM, the particles were those whose equivalent circular diameter was determined from the cross-sectional area in the microscope image, and whose value fell within ±10% of the number-average particle size (D1) obtained by the method described later using a Coulter counter.

[0038] The TEM images obtained from the above photography were opened using the image analysis software Image-ProPlusProPlus5.1J (Media Cybernetics), and "Count / Size - Manual Extraction - Range" was selected in the Measurement tab. In the color extraction window, the threshold was adjusted so that the silica microparticles were masked, and by clicking New Mask, the silica microparticles were converted into binarized image data. Of these, only silica microparticles were randomly analyzed. The presence of silica microparticles could be confirmed by EDX during the TEM observation described above. The primary particle diameter of the silica microparticles was defined as the average of the long and short axes of the particle. Furthermore, the number-average diameter of the primary particles of the silica microparticles was defined as the number-average of the primary particle diameters of 100 randomly selected primary particles. Furthermore, the presence of silica fine particles in the region 0.3 μm or more inward from the surface of the toner particle in the cross-sectional view of the toner particle was confirmed by the method described later, using the magnified cross-sectional photograph of the toner particle mentioned above.

[0039] The toner particles contain silica fine particles in a region of 0.3 μm or more from the surface of the toner particles. In this disclosure, the term "inside of toner particles" refers to the influence of external additives present on the surface of toner particles. This refers to the area that is not affected by [unclear], specifically meaning that silica microparticles are present in the region 0.3 μm or more inward from the surface of the toner particles. By including silica microparticles inside the toner particles, interaction with the binder resin occurs, making it possible to achieve both low-temperature fixation, resistance to hot offset, and resistance to bending. Silica microparticles can be included in the region 0.3 μm or more inward from the surface of the toner particles by mixing them with the binder resin, colorant, and other additives as needed during the toner particle manufacturing process. The percentage of silica microparticles located 0.3 μm or more from the surface of the toner particles is preferably 30-100%, and more preferably 90-95%, of the total number of silica microparticles contained in the toner particles.

[0040] <Method for confirming the location of silica microparticles within toner particles> The presence of silica microparticles in the region 0.3 μm or more from the surface of the toner particles can be confirmed by the following method. In the TEM images obtained by measuring the number-average particle size of the primary silica microparticles described above, 100 silica microparticles completely embedded in the toner particles were randomly extracted, and the percentage (number of particles) of silica microparticles located more than 0.3 μm from the surface of the toner particles was calculated. If the percentage of silica microparticles located more than 0.3 μm from the surface of the toner particles was 5% or more, it was determined that the toner particles contained silica microparticles more than 0.3 μm from the surface.

[0041] The silica fine particle content within the toner particles is preferably 0.1 to 15.0 parts by mass, and more preferably 1.0 to 10.0 parts by mass, per 100 parts by mass of the binder resin. When the silica fine particle content is within the above range, the binder resin and the silica fine particles can interact efficiently. As a result, the effects of low-temperature fixability, hot offset resistance, and bending resistance described above can be effectively obtained. These silica nanoparticles can be used individually or in combination of two or more. For example, silica nanoparticles surface-treated with a treatment agent having siloxane bonds may be used in combination with silica nanoparticles surface-treated with silicone oil or the like.

[0042] The toner particles contain a binder resin. Any known binder resin can be used. For example, the following are examples of binder resins: Styrene resins, styrene copolymer resins, polyester resins, polyol resins, polyvinyl chloride resins, phenol resins, naturally modified phenol resins, naturally modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone indene resins, and petroleum resins. Preferably used resins include styrene copolymer resins, polyester resins, and hybrid resins obtained by mixing polyester resin and styrene copolymer resin or by partial reaction of both. Polyester resins are particularly preferred in terms of bending resistance and hot offset resistance because the interaction between the ester bonds of the polyester resin and the siloxane bonds on the surface of the silica fine particles is stronger.

[0043] The components that make up polyester resin are described in detail. Note that depending on the type and application, one or more of the following components may be used. Examples of divalent carboxylic acid components constituting polyester resins include the following dicarboxylic acids or their derivatives: benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or their anhydrides or lower alkyl esters; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or their anhydrides or lower alkyl esters; alkenyl succinic acids or alkyl succinic acids with an average number of carbon atoms of 1 to 50, or their anhydrides or lower alkyl esters; Unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or their anhydrides or lower alkyl esters. Examples of alkyl groups in the lower alkyl ester include methyl, ethyl, propyl, and isopropyl groups.

[0044] On the other hand, the following are examples of divalent alcohol components that make up polyester resin. Ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated bisphenol A, bisphenols represented by the following formula (I-1) and their derivatives: and diols represented by the following formula (I-2). [ka]

[0045] In equation (I-1), R is an ethylene group or a propylene group, x and y are integers greater than or equal to 0, and the average value of x + y is between 0 and 10. [ka]

[0046] In equation (I-2), R' is an ethylene group or a propylene group, x' and y' are integers greater than or equal to 0, and the average value of x'+y' is between 0 and 10.

[0047] In addition to the divalent carboxylic acid and divalent alcohol components mentioned above, the components of the polyester resin may also contain trivalent or higher carboxylic acid components and trivalent or higher alcohol components. There are no particular limitations on the trivalent or higher carboxylic acid components, but examples include trimellitic acid, trimellitic anhydride, and pyromellitic acid. Examples of trivalent or higher alcohol components include trimethylolpropane, pentaerythritol, and glycerin.

[0048] In addition to the compounds mentioned above, the components of the polyester resin may also contain monovalent carboxylic acid components and monovalent alcohol components. Examples of monovalent carboxylic acid components include palmitic acid, stearic acid, arachidic acid, and behenic acid. Other examples include cerotic acid, heptacosanoic acid, montanic acid, melissic acid, laxeric acid, tetracontanoic acid, and pentacontanoic acid. Other examples of monohydric alcohol components include behenyl alcohol, ceryl alcohol, melicyl alcohol, and tetracontanol.

[0049] The method for producing the polyester resin is not particularly limited, and known methods can be used. For example, the above-mentioned divalent carboxylic acid component and divalent alcohol component can be polymerized via an esterification reaction or transesterification reaction, and a condensation reaction to produce the polyester resin. The polymerization temperature is not particularly limited, but a range of 180°C to 290°C is preferred. When polymerizing the polyester resin, polymerization catalysts such as titanium-based catalysts, tin-based catalysts, zinc acetate, antimony trioxide, and germanium dioxide can be used.

[0050] The binder resin preferably contains 50 to 100% by mass of a component with a molecular weight of 4,000 to 50,000, based on the mass of the tetrahydrofuran-soluble component, in the tetrahydrofuran-soluble component obtained by dissolving the binder resin in tetrahydrofuran. The content of components with a molecular weight of 4,000 to 50,000 in the binder resin is more preferably 55 to 90% by mass, and even more preferably 60 to 80% by mass. By satisfying the above conditions, the silica fine particles in the toner particles and the binder resin can interact effectively, resulting in better low-temperature fixation, hot offset resistance, and bending resistance.

[0051] The toner contains 50% by mass or more of a component with a molecular weight of 4,000 to 50,000, based on the mass of the tetrahydrofuran-soluble components, in the tetrahydrofuran-soluble components obtained by dissolving the toner in tetrahydrofuran. The content of components with a molecular weight of 4,000 to 50,000 in the toner is preferably 50 to 100% by mass, more preferably 55 to 90% by mass, and even more preferably 60 to 80% by mass. By satisfying the above conditions, the silica fine particles in the toner particles and the binder resin can interact effectively, resulting in better low-temperature fixing properties, hot offset resistance, and bending resistance.

[0052] The molecular weight of the THF-soluble components in the binder resin and toner is measured as follows. <Molecular weight measurement of THF-soluble components in binder resin and toner> The molecular weight distribution of THF-soluble components in the binder resin and toner is measured by GPC as follows. First, the toner is dissolved in THF at room temperature for 24 hours. Then, the resulting solution is filtered through a solvent-resistant membrane filter, "Maeshori Disc" (manufactured by Tosoh Corporation), with a pore diameter of 0.2 μm, to obtain the sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is approximately 0.8% by mass. This sample solution is then used for measurement under the following conditions. Equipment: HLC8120 GPC (Detector: RI) (Manufactured by Tosoh Corporation) Columns: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7-row) (manufactured by Showa Denko Corporation) Eluent:THF Flow rate: 1.0mL / min Oven temperature: 40.0℃ Sample injection volume: 0.10 mL For calculating the molecular weight of the sample, a molecular weight calibration curve created using, for example, the standard polystyrene resin manufactured by Tosoh Corporation (as shown below) is used. Standard polystyrene resin: Product names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500" From the calculated molecular weight of the sample, the content of components with molecular weights between 4,000 and 50,000 is determined.

[0053] The glass transition temperature Tg of the binder resin is preferably 50 to 65°C, and furthermore, 51 A temperature of ~62°C is more preferable. Having the binder resin's glass transition temperature within the above range allows for effective interaction with the silica fine particles in the toner particles, resulting in better low-temperature fixation, hot offset resistance, and bending resistance.

[0054] <Measurement of the glass transition temperature (Tg) of the binder resin> The glass transition temperature of the binder resin is measured using a differential scanning calorimetry analyzer "Q2000" (TA Instruments) in accordance with ASTM D3418-82. The temperature correction of the instrument's detection unit uses the melting points of indium and zinc, and the heat quantity correction is based on the melting point of indium. Use heat. Specifically, 3 mg of the binder resin is accurately weighed, placed in an aluminum pan, and measured under the following conditions using an empty aluminum pan as a reference. Heating rate: 10℃ / min Measurement start temperature: 20℃ Measurement end temperature: 180℃ Measurements are performed within the measurement range of 20 to 180°C at a heating rate of 10°C / min. The temperature is raised to 180°C and held for 10 minutes, then cooled to 20°C, and then heated again. During this second heating process, the specific heat change is obtained in the temperature range of 20 to 100°C. The temperature at the intersection of the differential heat curve and a straight line equidistant in the vertical direction from the "baseline before the specific heat change" and the "baseline after the specific heat change" is defined as the glass transition temperature of the resin (also called the Tg midpoint glass transition temperature).

[0055] The acid value of the binder resin is preferably 5.0 mg KOH / g or higher, and more preferably 8.0 mg KOH / g or higher. On the other hand, the upper limit of the acid value is preferably 20.0 mg KOH / g or lower, and more preferably 15.0 mg KOH / g or lower. By having a predetermined acid value, the binder resin can efficiently interact with the compounds having siloxane bonds bonded to the surface of the silica fine particles inside the toner particles, thereby improving bending resistance and hot offset resistance.

[0056] <Method for measuring the acid value of binder resin and toner> [Method for measuring the acid value of binder resins] The acid value is the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of the sample. The acid value of the binder resin is measured according to JIS K 0070-1992, but specifically, it is measured according to the following procedure. (1) Preparation of reagents Dissolve 1.0 g of phenolphthalein in 90 ml of ethyl alcohol (95% by volume), add deionized water to make a total volume of 100 ml, and obtain a phenolphthalein solution. Dissolve 7g of special grade potassium hydroxide in 5ml of water, and add ethyl alcohol (95% by volume) to make 1L. Place the mixture in an alkali-resistant container, taking care not to allow it to come into contact with carbon dioxide, etc., and leave it for 3 days. After that, filter the solution to obtain potassium hydroxide solution. Store the obtained potassium hydroxide solution in an alkali-resistant container. The factor of the potassium hydroxide solution is determined by taking 25 ml of 0.1 mol / l hydrochloric acid into an Erlenmeyer flask, adding a few drops of the phenolphthalein solution, titrating with the potassium hydroxide solution, and determining the amount of potassium hydroxide solution required for neutralization. The 0.1 mol / l hydrochloric acid used is prepared in accordance with JIS K 8001-1998.

[0057] (2) Operation (A) Main examination 2.0 g of the sample is accurately weighed into a 200 ml Erlenmeyer flask, and 100 ml of a toluene / ethanol (2:1) mixture is added. The sample is dissolved over 5 hours. Then, a few drops of the phenolphthalein solution are added as an indicator, and the sample is titrated with the potassium hydroxide solution. The titration endpoint is reached when the indicator turns a pale pink color for approximately 30 seconds. (B) Blank test The titration procedure is the same as described above, except that no sample is used (i.e., only a mixed solution of toluene / ethanol (2:1) is used).

[0058] (3) Substitute the obtained results into the following formula to calculate the acid value. A = [(CB) × f × 5.61] / S Here, A: Acid value (mgKOH / g), B: Amount of potassium hydroxide solution added in the blank test (m l) C: Amount of potassium hydroxide solution added in this test (ml), f: Factor of potassium hydroxide solution, S: Sample (g). [Method for measuring the acid value of toner] For the toner, the sample volume was adjusted, and measurements were taken using the same procedure as described above.

[0059] The softening point Tm of the binder resin is preferably 85 to 150°C, and more preferably 90 to 130°C. Having the binder resin softening point within this range allows for effective interaction with the silica fine particles inside the toner particles, resulting in better low-temperature fixation, hot offset resistance, and bending resistance. The binder resin may be a combination of binder resin A with a low softening point and binder resin B with a high softening point. The softening point of binder resin A is preferably 70 to 100°C. The softening point of binder resin B with a high softening point is preferably 100 to 160°C. The content ratio (A / B) of binder resin A with a low softening point and binder resin B with a high softening point is not particularly limited, but is preferably 60 / 40 to 90 / 10. The softening point of the binder resin is measured as follows.

[0060] <Method for measuring the softening point of binder resin> The softening point of the binder resin is measured using a constant-load extrusion type capillary rheometer, the "Flow Characteristics Evaluation Device Flow Tester CFT-500D" (manufactured by Shimadzu Corporation), according to the manual included with the device. With this device, a constant load is applied from the top of the sample by a piston, the sample filled in the cylinder is heated and melted, and the molten sample is extruded from a die at the bottom of the cylinder. A flow curve showing the relationship between the piston descent amount and temperature can be obtained. The softening point will be the "melting temperature using the 1 / 2 method" as described in the manual included with the "Flow Characteristics Evaluation Device Flow Tester CFT-500D". The melting temperature using the 1 / 2 method is calculated as follows:

[0061] First, we calculate half the difference between the piston's descent Smax at the end of the outflow and the piston's descent Smin at the start of the outflow (let's call this X; X = (Smax - Smin) / 2). Then, the temperature on the flow curve when the piston's descent is the sum of X and Smin is the melting temperature Tm using the 1 / 2 method. The sample used for measurement is a cylindrical shape with a diameter of approximately 8 mm, prepared by compressing approximately 1.3 g of the sample at approximately 10 MPa for approximately 60 seconds using a tablet molding compressor (e.g., NT-100H, manufactured by NPA System Co., Ltd.) in an environment of 25°C. The measurement conditions for the CFT-500D are as follows: Test mode: Temperature increase method Starting temperature: 50℃ Achieved temperature: 200℃ Measurement interval: 1.0℃ Heating rate: 4.0℃ / min Piston cross-sectional area: 1,000 cm² 2 Test load (piston load): 10.0 kgf (0.9807 MPa) Preheating time: 300 seconds Die hole diameter: 1.0mm Die length: 1.0mm

[0062] The toner can be used as either a magnetic one-component toner, a non-magnetic one-component toner, or a non-magnetic two-component toner. When used as a single-component magnetic toner, magnetic iron oxide particles are preferably used as the colorant. Examples of magnetic iron oxide particles contained in a single-component magnetic toner include magnetite and maghemite. Examples include magnetic iron oxides such as iron oxide and ferrite, and magnetic iron oxides including other metal oxides; metals such as Fe, Co, and Ni, or alloys of these metals with metals such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, and V, and mixtures thereof. The content of magnetic iron oxide particles is preferably 30 to 150 parts by mass per 100 parts by mass of the binder resin.

[0063] Examples of colorants used when used as non-magnetic one-component toners and non-magnetic two-component toners include the following: As black pigments, carbon blacks such as furnace black, channel black, acetylene black, thermal black, and lamp black are used, as well as magnetic powders such as magnetite and ferrite. Suitable colorants for the yellow color include pigments or dyes. Examples of pigments include CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 23, 62, 65, 73, 74, 81, 83, 93, 94, 95, 97, 98, 109, 110, 111, 117, 120, 127, 128, 129, 137, 138, 139, 147, 151, 154, 155, 167, 168, 173, 174, 176, 180, 181, 183, 191, and CI Bat Yellow 1, 3, 20. Examples of dyes include CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, and 162. These can be used individually or in combination of two or more.

[0064] Suitable colorants for cyan include pigments or dyes. Examples of pigments include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66, CI Bat Blue 6, and CI Acid Blue 45. Examples of dyes include CI Solvent Blue 25, 36, 60, 70, 93, and 95. These can be used individually or in combination of two or more.

[0065] Suitable colorants for magenta include pigments or dyes. Examples of pigments include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57, 57:1, 58, 60, 63, 64, 68, Examples include 81, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, CI Pigment Violet 19; CI Bat Red 1, 2, 10, 13, 15, 23, 29, 35. Examples of magenta dyes include oil-soluble dyes such as CI Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, 122, CI Disperse Red 9, CI Solvent Violet 8, 13, 14, 21, 27, and CI Disperse Violet 1, as well as basic dyes such as CI Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, and CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28. These can be used individually or in combination of two or more. The coloring agent content is preferably 1 to 20 parts by mass per 100 parts by mass of the binder resin.

[0066] A release agent (wax) may be used to give the toner release properties. Examples of waxes include: aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, olefin copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxidized forms of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; waxes mainly composed of fatty acid esters such as carnauba wax, behenyl behenate, and montanate ester wax; and waxes in which fatty acid esters have been partially or completely deoxidized, such as deoxidized carnauba wax. Furthermore, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; saturated fatty acid bisamides such as methylenebisstearate, ethylenebiscaprate, ethylenebislaurate, and hexamethylenebisstearate; ethylenebisoleamide, hexamethylenebisoleamide, N,N Examples include unsaturated fatty acid amides such as '-dioleyl adipic acid amide and N,N'-dioleyl sebacin acid amide; aromatic bisamides such as m-xylene bisstearamide and N,N'-distearyl isophthalic acid amide; fatty acid metal salts (generally known as metal soaps) such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes grafted onto aliphatic hydrocarbon waxes with vinyl copolymer monomers such as styrene and acrylic acid; partially esterified fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils and fats.

[0067] Particularly preferred waxes are aliphatic hydrocarbon waxes. For example, preferred waxes include low molecular weight hydrocarbons obtained by radical polymerization of alkylenes under high pressure or polymerization of Ziegler catalysts or metallocene catalysts under low pressure; Fischer-Tropsch waxes synthesized from coal or natural gas; paraffin waxes; olefin polymers obtained by thermal decomposition of high molecular weight olefin polymers; synthetic hydrocarbon waxes obtained from the distillation residue of hydrocarbons obtained by the Aage process from synthesis gas containing carbon monoxide and hydrogen, or synthetic hydrocarbon waxes obtained by hydrogenation of these.

[0068] Furthermore, it is more preferable to use hydrocarbon waxes that have been separated by methods such as press efflorescence, solvent method, vacuum distillation, or fractional crystallization. In particular, among paraffin waxes, n-paraffin wax and Fischer-Tropsch wax, which mainly consist of linear components, are preferred from the viewpoint of molecular weight distribution. These waxes may be used individually or in combination of two or more types. Preferably, 1 to 20 parts by mass of wax are added per 100 parts by mass of binder resin.

[0069] A charge control agent may be used in the toner. Known charge control agents can be used. Examples include azo iron compounds, azo chromium compounds, azo manganese compounds, azo cobalt compounds, azo zirconium compounds, chromium compounds of carboxylic acid derivatives, zinc compounds of carboxylic acid derivatives, aluminum compounds of carboxylic acid derivatives, and zirconium compounds of carboxylic acid derivatives. The carboxylic acid derivative is preferably an aromatic hydroxycarboxylic acid. A charge-controlling resin can also be used. If necessary, one or more charge-controlling agents may be used in combination. It is preferable to use 0.1 to 10 parts by mass of the charge-controlling agent per 100 parts by mass of the binder resin.

[0070] The toner may be mixed with a carrier and used as a two-component developer. As the carrier, ordinary carriers such as ferrite and magnetite, or resin-coated carriers can be used. Alternatively, magnetic material-dispersed resin particles in which magnetic material powder is dispersed in the resin component, or porous magnetic core particles containing resin in the voids can be used.

[0071] Various magnetic iron compound particle powders can be used as magnetic material components in magnetic material-dispersed resin particles, including magnetite particle powder, maghemite particle powder, or magnetic iron oxide particle powder containing at least one selected from silicon oxide, silicon hydroxide, aluminum oxide, and aluminum hydroxide; magnetoplanvite-type ferrite particle powder containing barium, strontium, or barium-strontium; and spinel-type ferrite particle powder containing at least one selected from manganese, nickel, zinc, lithium, and magnesium.

[0072] Furthermore, in addition to magnetic components, non-magnetic inorganic compound particle powders such as hematite particle powder, non-magnetic hydrated ferric oxide particle powder, goethite particle powder, titanium oxide particle powder, silica particle powder, talc particle powder, alumina particle powder, barium sulfate particle powder, barium carbonate particle powder, cadmium yellow particle powder, calcium carbonate particle powder, and zinc oxide particle powder may be used in combination with magnetic iron compound particle powder.

[0073] Examples of materials for porous magnetic core particles include magnetite or ferrite. A specific example of ferrite is shown by the following general formula. (M12O) x (M2O) y (Fe2O3) Z In the above equation, M1 is a monovalent metal and M2 is a divalent metal. When x + y + z = 1.0, x and y are 0 ≤ (x, y) ≤ 0.8, and z is 0.2. <z<1.0である) In the formula, it is preferable to use at least one metal atom selected from the group consisting of Li, Fe, Mn, Mg, Sr, Cu, Zn, and Ca as M1 and M2. Other metals that can be used include Ni, Co, Ba, Y, V, Bi, In, Ta, Zr, B, Mo, Na, Sn, Ti, Cr, Al, Si, and rare earth elements.

[0074] The carrier preferably has magnetic carrier core particles and a resin coating layer formed on the surface of the magnetic carrier core particles as a resin-coated carrier. The resin coating layer, for example, coats the surface of the magnetic carrier core particles. The magnetic carrier core particles are preferably porous magnetic core particles that contain resin in their voids. The method for coating the surface of magnetic carrier core particles with resin is not particularly limited, but examples include immersion, spraying, brush application, and coating methods such as a fluidized bed.

[0075] Examples of resins used in the resin coating layer include acrylic resins such as acrylic acid ester copolymers and methacrylic acid ester copolymers, styrene-acrylic resins such as styrene-acrylic acid ester copolymers and styrene-methacrylic acid ester copolymers, fluorine-containing resins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, monochlorotrifluoroethylene polymer, and polyvinylidene fluoride, silicone resins, polyester resins, polyamide resins, polyvinyl butyral, aminoacrylate resins, iomonomer resins, and polyphenylene sulfide resins. These resins can be used individually or in combination.

[0076] Among these, copolymers containing (meth)acrylic acid esters having alicyclic hydrocarbon groups are particularly preferred from the viewpoint of electrostatic stability. Examples of methacrylate esters having alicyclic hydrocarbon groups include cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, and cyclohexyl acrylate. Examples include butyl, dicyclopentenyl acrylate, dicyclopentanyl acrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, dicyclopentenyl methacrylate, and dicyclopentanyl methacrylate. The alicyclic hydrocarbon group is preferably a cycloalkyl group, with 3 to 10 carbon atoms, and more preferably 4 to 8 carbon atoms. These may be used individually or in combination of two or more.

[0077] Furthermore, from the viewpoint of charge stability, it is more preferable that the resin coating layer contains macromonomers as copolymer components in order to improve adhesion between the magnetic carrier core particles and the resin coating layer and to suppress local peeling of the resin coating layer. An example of a specific macromonomer is shown in formula (B). That is, it is preferable that the resin in the resin coating layer has monomer units made up of macromonomers represented by the following formula (B). [ka]

[0078] In formula (B), A represents a polymer of at least one compound selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, acrylonitrile, and methacrylonitrile. 3 It is either H or CH3. A is preferably a polymer of methyl methacrylate.

[0079] External additives may be added to the toner as needed. Examples of external additives include resin fine particles and inorganic fine powders that function as charge enhancers, conductivity enhancers, fluidity enhancers, caking inhibitors, release agents during hot roller fixing, lubricants, and abrasives. Examples of charge enhancers include metal oxides such as silica, titanium dioxide, zinc oxide, and alumina. Examples of lubricants include polyfluoroethylene powder, zinc stearate powder, and polyvinylidene fluoride powder. Examples of abrasives include cerium oxide powder, silicon carbide powder, and strontium titanate powder. When silica is used as an external additive, the type of silica is not particularly limited, but it is preferable to use silica fine particles that satisfy the above-mentioned properties to be contained inside the toner particles. In this case, the silica fine particles used as an external additive may be the same as the silica fine particles contained inside the toner particles, or different silica fine particles may be used. The apparatus used for mixing the toner particles with the external additive is not particularly limited, and known mixers such as Henschel mixers can be used. The amount of external additive added is preferably 0.01 to 10.00 parts by mass per 100 parts by mass of toner particles.

[0080] In the process of obtaining toner particles, the method for producing the toner particles is not particularly limited and can be produced by known methods. Examples include grinding, emulsification and agglomeration, suspension polymerization, and dissolution and suspension methods. The toner particles are preferably ground toner particles (melt-kneaded ground toner particles).

[0081] Toner particles produced by the pulverization method are manufactured, for example, as follows: (Raw material mixing process) The binder resin, silica microparticles, colorant, and other additives as needed are thoroughly mixed using a mixer such as a Henschel mixer or ball mill. (Melting and mixing process) The mixture is melt-kneaded using a hot kneader such as a twin-screw extruder, heated roll, kneader, or extruder to disperse silica particles, colorants, and other additives. Wax, magnetic iron oxide particles, and metal-containing compounds may also be added at this stage. After melt-kneading, the molten mixture is cooled and solidified. (Grinding process) After the cooled molten mixture is coarsely ground, it is finely ground to the desired particle size. During this process, the average circularity of the toner particles can be controlled by adjusting the exhaust temperature. The resulting pulverized material is then classified to obtain toner particles. If necessary, the toner particles and external additives can be mixed using a mixer such as a Henschel mixer to obtain toner.

[0082] Examples of mixing machines include: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); Super Mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Co., Ltd.); Spiral Pin Mixer (manufactured by Taiheiyo Kiko Co., Ltd.); and Redigge mixer (manufactured by Matsubo Co., Ltd.).

[0083] Examples of mixing machines include: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co.); TEX twin-screw mixer (manufactured by Japan Steel Works); PCM mixer (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); NideX (manufactured by Mitsui Mining Co.); MS type pressure kneader, Nidaruder (manufactured by Moriyama Seisakusho); Banbury mixer (manufactured by Kobe Steel).

[0084] Examples of crushing machines include: counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Co., Ltd.); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); Ulmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Industries Co., Ltd.); and Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0085] Furthermore, if necessary, after grinding, the surface treatment of the toner particles can be performed using a hybridization system (manufactured by Nara Machine Works), Nobilta (manufactured by Hosokawa Micron Corporation), Mechanofusion system (manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation), Inomizer (manufactured by Hosokawa Micron Corporation), Theta Composer (manufactured by Tokuju Kogyo Co., Ltd.), Mechanomill (manufactured by Okada Seikou Co., Ltd.), or Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.) to control the average circularity of the toner particles.

[0086] Examples of classifiers include: Classil, Micron Classifier, Spedick Classifier (manufactured by Seishin Corporation); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yaskawa Trading Co., Ltd.).

[0087] Examples of sieving devices used to separate coarse particles include: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona Sieve, Gyro Shifter (manufactured by Tokuju Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Engineering Co., Ltd.); Micro Shifter (manufactured by Makino Sangyo Co., Ltd.); and circular vibrating screen.

[0088] <Measurement of weight-average particle size (D4) and number-average particle size (D1) of toner> The weight-average particle size (D4) and number-average particle size (D1) of the toner are measured within a 100 μm aperture. The precision particle size distribution analyzer "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter), equipped with a tube and using the pore electrical resistance method, and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) for setting measurement conditions and analyzing measurement data, are used to perform measurements with an effective measurement channel count of 25,000, and the measurement data is analyzed and calculated. The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of approximately 1% by mass; for example, "ISOTON II" (manufactured by Beckman Coulter) can be used. Before performing measurements and analysis, configure the dedicated software as follows. In the dedicated software's "Change Standard Measurement Method (SOM)" screen, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter). Press the Threshold / Noise Level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the box for flushing the aperture tube after measurement. In the dedicated software's "Pulse to Particle Size Conversion Settings Screen," set the bin spacing to logarithmic particle size, the particle size bins to 256 particle size bins, and the particle size range from 2 μm to 60 μm.

[0089] The specific measurement method is as follows: (1) Pour approximately 200 ml of the electrolytic solution into a 250 ml round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir the mixture with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Tube Flash" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Place approximately 30 ml of the electrolytic aqueous solution into a 100 ml flat-bottomed glass beaker, and add approximately 0.3 ml of a diluted solution of "Contaminon N" (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with deionized water as a dispersant. (3) Two oscillators with an oscillation frequency of 50 kHz are built in with their phases shifted by 180 degrees, and a predetermined amount of deionized water is placed in the water tank of an ultrasonic dispersion device called "Ultrasonic Dispersion System Tetora150" (manufactured by Nikko Bios Co., Ltd.) with an electrical output of 120 W. Approximately 2 ml of the aforementioned Contaminon N is added to this water tank. (4) Place the beaker from (2) into the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic aqueous solution inside the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) with ultrasound, add approximately 10 mg of toner particles to the electrolytic aqueous solution in small amounts and disperse them. Continue the ultrasonic dispersion treatment for another 60 seconds. During ultrasonic dispersion, adjust the water temperature in the tank to be between 10°C and 40°C as appropriate. (6) Using a pipette, the electrolytic aqueous solution (5) containing dispersed toner particles is dropped into the round-bottom beaker (1) placed in the sample stand, and the concentration is adjusted to approximately 5%. The measurement is then continued until the number of particles reaches 50,000. (7) The measurement data is analyzed using the dedicated software attached to the device to calculate the number-average particle size (D1) and the weight-average particle size (D4). Note that when the dedicated software is set to graph / number% and graph / volume%, the "arithmetic diameter" on the analysis / number statistics (arithmetic mean) and analysis / volume statistics (arithmetic mean) screens are the number-average particle size (D1) and weight-average particle size (D4), respectively.

[0090] <Method for measuring average circularity> The average circularity of toner particles is measured using the flow-type particle image analyzer "FPIA-3000" (Sysm Measurements are taken using a device manufactured by X Corporation under the same measurement and analysis conditions as during the calibration process. The specific measurement method is as follows: First, put about 20 mL of deionized water, from which impurities and other solids have been removed, into a glass container. Add about 0.2 mL of a diluted solution of "Contaminon N" (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.), which has been diluted with deionized water to about 3 times its original volume, as a dispersant. Next, add approximately 0.02 g of the sample to be measured and disperse it using an ultrasonic disperser for 2 minutes to obtain the dispersion for measurement. During this process, cool the dispersion as needed so that its temperature is between 10°C and 40°C. As the ultrasonic disperser, a tabletop ultrasonic cleaner disperser ("VS-150" (manufactured by Velvoclea Co., Ltd.)) with an oscillation frequency of 50 kHz and an electrical output of 150 W is used. A predetermined amount of deionized water is placed in the water tank, and approximately 2 mL of the aforementioned Contaminon N is added to this water tank.

[0091] For measurement, a flow-type particle image analyzer equipped with a standard objective lens (10x) is used, and particle sheath "PSE-900A" (manufactured by Sysmex Corporation) is used as the sheath solution. The dispersion prepared according to the above procedure is introduced into the flow-type particle image analyzer, and 3,000 toner particles are measured in HPF measurement mode and total count mode. Then, the binarization threshold for particle analysis is set to 85%, and the analyzed particle diameter is limited to a circular equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is determined. Before starting the measurement, autofocus adjustment should be performed using standard latex particles (Duke Scientific's "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" diluted with deionized water). Subsequently, it is preferable to perform focus adjustment every two hours from the start of the measurement. In this embodiment, a flow-type particle image analyzer was used, which had been calibrated by Sysmex Corporation and for which a calibration certificate was issued by Sysmex Corporation. Except for limiting the analyzed particle size to a circular equivalent diameter of 1.985 μm or more and less than 39.69 μm, measurements were performed under the same measurement and analysis conditions as when the calibration certificate was received. [Examples]

[0092] The basic structure and features of the present invention have been described above. The present invention will now be described in detail based on examples. However, the present invention is not limited thereto. Unless otherwise specified, parts and percentages are based on mass.

[0093] <Manufacturing example of binding resin EL1> • Bisphenol A propylene oxide (2.2 molar adduct): 100.0 molar parts Terephthalic acid: 90.0 molar parts • Trimellitus anhydride: 10.0 moles 100 parts by mass of the monomer constituting the above polyester unit was mixed with 500 ppm of titanium tetrabutoxide in a 5-liter autoclave. A reflux condenser, moisture separator, N2 gas introduction tube, thermometer, and stirring device were attached to the autoclave, and a condensation polymerization reaction was carried out at 230°C while introducing N2 gas into the autoclave. The reaction time was adjusted to achieve the desired softening point, and after the reaction was complete, the material was removed from the container, cooled, and pulverized to obtain the binder resin EL1. The Tm of binder resin EL1 was 92°C, the Tg was 54°C, and the acid value was 8.0 mgKOH / g. Other physical properties are shown in Table 1.

[0094] <Manufacturing examples of binding resins EL2~EL5> As shown in Table 1, binder resins EL2 to EL5 were obtained by following the production example of binder resin EL1, except that the amount of monomer added was changed and the reaction time was adjusted to change Tm and Tg. The physical properties of the adhesive resins EL2 to EL5 are shown in Table 1.

[0095] <Example of manufacturing of binder resin EH1> • Bisphenol A propylene oxide (2.2 molar adduct): 100.0 molar parts • Terephthalic acid: 90.0 molar parts The above materials were weighed into a reaction vessel equipped with a condenser, stirrer, nitrogen inlet tube, and thermocouple. Furthermore, 500 ppm titanium tetrabutoxide was added to the reaction vessel. Next, the flask was purged with nitrogen gas, and the temperature was gradually increased while stirring. The reaction was then carried out at 200°C with stirring for 2 hours. Furthermore, the pressure inside the reaction vessel was reduced to 8.3 kPa and maintained for 1 hour, then cooled to 180°C and returned to atmospheric pressure (first reaction step). • Trimellitus anhydride: 10.0 moles Subsequently, 0.003 molar parts of tert-butylcatechol (polymerization inhibitor) were added to the reaction vessel along with the above materials. The pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 160°C. After confirming that the softening point, measured according to ASTM D36-86, reached 128°C, the temperature was lowered to stop the reaction (second reaction step), and the binder resin EH1 was obtained. The softening point (Tm) of the obtained binder resin EH1 was 128°C, and the glass transition temperature (Tg) was 62°C.

[0096] <Examples of manufacturing binder resins EH2~EH4> As shown in Table 1, binder resins EH2 to EH4 were obtained by following the production example of binder resin EH1, except that the amount of monomer added was changed and the reaction time was adjusted to change Tm and Tg. The physical properties of the obtained binder resins EH2 to EH4 are shown in Table 1. [Table 1]

[0097] In Table 1 above, "Specific Molecular Weight Content" refers to the content of components with a molecular weight of 4,000 to 50,000 relative to the tetrahydrofuran-soluble content obtained by dissolving the binder resin in tetrahydrofuran. Furthermore, the abbreviations in Table 1 above have the following meanings: BPA-PO: Propylene oxide adduct of bisphenol A (average number of moles added: 2.2 mol) TPA: Terephthalic acid Anhydrous TMA: Trimellitus anhydrous

[0098] <Example of manufacturing silica microparticles NS1> 100g of fumed silica (silica microparticle substrate: spherical) with a number average particle size of 110nm was placed in a stainless steel (SUS304) reaction vessel connected to a vacuum pump, and the inside of the reaction vessel was 0 The pressure was reduced to 0.001 Pa, and the mixture was heated and stirred to control the temperature of the reaction vessel to 330°C. After a 30-minute degassing treatment in this state, octamethylcyclotetrasiloxane vapor was introduced as a surface treatment agent. While supplying it at a rate of 10 g / min for 5 minutes, the opening of the valve between the vacuum pump and the reaction vessel was adjusted to control the pressure inside the reaction vessel to 1 Pa. After supplying octyltrisiloxane vapor, the silica nanoparticle substrate was surface-treated by heating and stirring for 40 minutes. Subsequently, the reaction vessel was evacuated under reduced pressure to 0.001 Pa to remove the reaction products and unreacted surface treatment agent. After 30 minutes of degassing in this state, octamethylcyclotetrasiloxane vapor was again introduced as the surface treatment agent, supplied at a rate of 10 g / min for 5 minutes while controlling the pressure inside the reaction vessel to 1 Pa. After supplying octyltrisiloxane vapor, the silica nanoparticles underwent a second surface treatment by heating and stirring for 40 minutes. After a 30-minute degassing treatment in this state, octamethylcyclotetrasiloxane vapor was introduced again as a surface treatment agent, supplied at a rate of 10 g / min for 5 minutes while controlling the pressure inside the reaction vessel to 1 Pa. After supplying octyltrisiloxane vapor, the silica nanoparticles underwent a third surface treatment by heating and stirring for 40 minutes. Subsequently, while continuing to heat and stir, the reaction vessel was evacuated under reduced pressure to 0.001 Pa to remove unreacted surface treatment agents, thereby obtaining silica fine particles NS1. The physical properties of the obtained silica fine particles are shown in Table 2-2.

[0099] <Examples of manufacturing silica microparticles NS2-NS12> Fumed silica (silica microparticle substrate; spherical) with the number-average particle size shown in Table 2-1 was manufactured in the same manner as silica microparticle NS1, except that the treatment agent and treatment conditions were changed as shown in Table 2-1.

[0100] <Example of manufacturing silica microparticles GS1> 100 g of fumed silica (silica nanoparticle substrate; spherical) with a number-average particle size of 5 nm was placed in a reaction vessel, and while stirring under a nitrogen atmosphere, silicone oil was supplied to the reaction vessel at a rate of 10 g / min for 20 minutes at room temperature, and the mixture was stirred for 30 minutes at room temperature to obtain silica nanoparticles GS1.

[0101] [Table 2-1] [Table 2-2]

[0102] The abbreviations in Table 2-1 above have the following meanings: D3: Hexamethylcyclotrisiloxane D4: Octamethylcyclosiloxane D5: Pentamethylcyclosiloxane PDMS: Polydimethylsiloxane Reactive silicone oil: End-ended alcohol-modified silicone oil

[0103] <Example 1> • 70 units of EL1 binding resin • Binding resin EH1 30 parts Fischer-Tropsch wax (melting point: 90°C) 5 parts • Silica microparticles NS1 4 parts • Silica microparticles NS12 3 parts CI Pigment Blue 15:3 5 parts The above materials were pre-mixed using a Henschel mixer (product name: FM-10C, manufactured by Nippon Coke Co., Ltd.), and then melt-kneaded at 160°C using a twin-screw kneading extruder. The resulting mixture was cooled, coarsely ground in a hammer mill, and then finely ground in a turbo mill. The obtained finely ground material was classified using a multi-segment classifier utilizing the Coanda effect to obtain toner particles with a weight-average particle size (D4) of 6.5 μm. To 100 parts of the obtained toner particles, 3.0 parts of silica fine particles NS1 were mixed using a Henschel mixer (product name: FM-10C, manufactured by Nippon Coke Co., Ltd.) at a rotation speed of 3000 rpm, a rotation time of 2 min, and an external addition temperature of room temperature. The mixture was then sieved through a mesh with a mesh opening of 150 μm to obtain toner 1. The physical properties of the obtained toner are shown in Table 3-2.

[0104] <Example of manufacturing magnetic carrier core particle 1> Process 1 (Weighing and Mixing Process) Fe2O368.3% by mass MnCO328.5% by mass Mg(OH)22.0% by mass SrCO31.2% by mass The above ferrite raw materials were weighed, and 20 parts water was added to 80 parts ferrite raw materials. Then, a slurry was prepared by wet mixing for 3 hours using a zirconia ball mill with a diameter (φ) of 10 mm. The solid content concentration of the slurry was 80% by mass.

[0105] Step 2 (Calibration Process) After drying the mixed slurry using a spray dryer (manufactured by Okawara Chemical Machinery Co., Ltd.), calcined ferrite was produced by firing it in a batch-type electric furnace under a nitrogen atmosphere (oxygen concentration 1.0 vol%) at a temperature of 1050°C for 3.0 hours.

[0106] Step 3 (Grinding Process) Calcined ferrite was crushed to approximately 0.5 mm using a crusher, and then water was added to prepare a slurry. The solid content concentration of the slurry was set to 70% by mass. This slurry was then ground for 3 hours in a wet ball mill using 1 / 8-inch stainless steel beads to obtain a slurry. This slurry was further ground for 4 hours in a wet bead mill using 1 mm diameter zirconia to obtain a calcined ferrite slurry with a volume-based 50% particle size (D50) of 1.3 μm.

[0107] Process 4 (granulation process) To 100 parts of the above calcined ferrite slurry, 1.0 part of ammonium polycarboxylate was added as a dispersant and 1.5 parts of polyvinyl alcohol was added as a binder. The mixture was then granulated into spherical particles using a spray dryer (manufactured by Okawara Chemical Machinery Co., Ltd.) and dried. After adjusting the particle size of the resulting granules, the mixture was heated in a rotary electric furnace at 700°C for 2 hours to remove organic matter such as dispersants and binders.

[0108] Step 5 (Baking process) Under a nitrogen atmosphere (oxygen concentration 1.0 vol%), the granules were fired by raising the temperature from room temperature to the firing temperature (1100°C) in 2 hours, and then maintaining the temperature at 1100°C for 4 hours. After that, the temperature was lowered to 60°C over 8 hours, the atmosphere was returned from nitrogen to air, and the fired material was removed at a temperature of 40°C or lower.

[0109] Process 6 (Sorting Process) After crushing the aggregated particles in the resulting calcined material, coarse particles were removed by sieving with a 150 μm mesh sieve, fine powder was removed by air classification, and low magnetic force components were further removed by magnetic separation to obtain porous magnetic core particles.

[0110] Process 7 (filling process) 100 parts of porous magnetic core particles 1 were placed in the stirring container of a mixing and stirring machine (Dalton NDMV type universal stirring machine), and 5 parts of a filling resin consisting of methyl silicone oligomer: 95.0% by mass and γ-aminopropyltrimethoxysilane: 5.0% by mass were added dropwise at atmospheric pressure while maintaining a temperature of 60°C.

[0111] After the dropping was complete, stirring was continued while adjusting the time, and the temperature was raised to 70°C to fill the particles of each porous magnetic core with the resin composition. The resin-filled magnetic core particles obtained after cooling were transferred to a mixer with spiral blades (UD-AT drum mixer manufactured by Sugiyama Heavy Industries Co., Ltd.) in a rotatable mixing container, and the temperature was raised to 140°C at a heating rate of 2°C / min under a nitrogen atmosphere while stirring. Heating and stirring were then continued at 140°C for 50 minutes. The ferrite particles were then cooled to room temperature, filled with resin, and hardened. Non-magnetic materials were removed using a magnetic separator. Coarse particles were then removed using a vibrating screen to obtain resin-filled magnetic carrier core particles 1.

[0112] (Examples of coating resin manufacturing) • Cyclohexyl methacrylate monomer 26.8% by mass • Methyl methacrylate monomer 0.2% by mass • Methyl methacrylate macromonomer 8.4% by mass (a macromonomer with a weight-average molecular weight of 5000, having a methacryloyl group at one end, represented by formula (B), where A is a polymer of methyl methacrylate) • Toluene 31.3% by mass • Methyl ethyl ketone 31.3% by mass • Azobisisobutyronitrile 2.0% by mass Of the above materials, cyclohexyl methacrylate monomer, methyl methacrylate monomer, methyl methacrylate macromonomer, toluene, and methyl ethyl ketone were placed in a four-necked separable flask equipped with a reflux condenser, thermometer, nitrogen inlet tube, and stirrer. After introducing nitrogen gas into the separable flask to create a sufficient nitrogen atmosphere, the mixture was heated to 80°C, azobisisobutyronitrile was added, and polymerization was carried out under reflux for 5 hours. Hexane was injected into the resulting reactant to precipitate the copolymer. The resulting precipitate was filtered off and then vacuum-dried to obtain the resin. Thirty parts of the resin were dissolved in a mixed solvent of 40 parts toluene and 30 parts methyl ethyl ketone to obtain a resin solution (solid content concentration 30%).

[0113] (Preparation of coating resin solution) • Resin solution (solid content concentration 30%) 33.3% by mass • Toluene 66.4% by mass • Carbon black (Regal 330; manufactured by Cabot) 0.3% by mass (number average particle size of primary particles: 25 nm, nitrogen adsorption specific surface area: 94 m²) 2 / g, DBP oil absorption: 75ml / 100g) The above materials were placed in a paint shaker and dispersed for 1 hour using zirconia beads with a diameter of 0.5 mm. The resulting dispersion was filtered through a 5.0 μm membrane filter to obtain a coating resin solution.

[0114] (Example of manufacturing magnetic carrier 1) The coating resin solution and magnetic carrier core particles were added to a vacuum-degassed kneader maintained at room temperature (the amount of coating resin solution added was 2.5 parts of resin component for every 100 parts of magnetic core particles). After adding the solvent, the mixture was stirred at a rotation speed of 30 rpm for 15 minutes. Once a certain amount (80%) of the solvent had evaporated, the temperature was raised to 80°C while mixing under reduced pressure. Toluene was then removed by distillation over 2 hours, followed by cooling. The obtained magnetic carriers were separated for low magnetic force by magnetic separation, passed through a sieve with an opening of 70 μm, and then classified using an air classifier to obtain magnetic carrier 1 with a 50% particle size (D50) of 38.2 μm based on volume distribution.

[0115] <Example of Developer 1 Manufacturing> Toner 1 and magnetic carrier 1 are mixed using a V-type mixer (V-10 model: Tokuju Seisakusho Co., Ltd.) in a manner that results in 10 parts toner 1 for every 90 parts magnetic carrier 1, in 0.5s. -1 Developer 1 was prepared by mixing under conditions of a rotation time of 5 minutes. The following evaluations were performed using the obtained developer 1.

[0116] <Bending resistance evaluation> I am using a Canon imagePRESS C10010VP production printer. The device was modified to allow adjustment of image density and process speed, and used as an image forming apparatus. A solid image was output, and the image density was adjusted to 1.80. The evaluation paper used was thin paper: GF-C081 (81.4 g / m²). 2 ), cardboard: mirror-coated platinum (209.0g / m2) (Kiya We used a product sold by Nonmarketing Japan. The process speed was adjusted to 120 A4 single-sided pages per minute. Mandrel testing was performed on the output images. The mandrel testing apparatus was a cylindrical mandrel. A mandrel bending tester (manufactured by Cortec Co., Ltd.) was used. A mandrel with a diameter of Φ2 mm was used. The image was placed on the mandrel test apparatus and folded 180°. The folded portion was rubbed with a 200g weight placed on a piece of lens tissue to peel the image off the paper. Three points on the peeled portion of the image were read using PIAS (manufactured by QEA), and the area of ​​the portion of the folded area that did not peel was quantified and calculated using the image processing software ImageJ.

[0117] This section explains the ImageJ analysis method. The image to be evaluated is opened in ImageJ and converted to 8-bit. Next, a Threshhold process is performed to separate the areas where peeling has occurred from those where it has not. A Rectangle process is used to place the peeled area within a specified range of 500 pixels wide x 70 pixels high and perform the analysis to calculate the TotalArea: Area A. Next, the specified area was moved to the area where no peeling had occurred, and TotalArea: Area B was calculated. Subsequently, the area ratio of the part where no peeling occurred was quantified by Area A / Area B. The values ​​obtained above were used to indicate the bending resistance of the printed image, and were evaluated according to the following criteria. (Evaluation Criteria) A: Bending resistance of 90% or more B: Bending resistance is less than 90% but 80% or more. C: Bending resistance less than 80% or more than 70% D: Bending resistance of 70% or more

[0118] <Evaluation of low-temperature fixation> The imagePRESS C10010VP fuser (manufactured by Canon) can operate independently. It was modified and used as an image forming apparatus. The fuser temperature was controlled in 2°C increments starting from 180°C. GFC-300 (A4 size, basis weight 300.0 g / m²) was used as the evaluation paper. 2Using a Canon Marketing Japan Inc. printer, a 2cm x 5cm solid image was placed in the center of the paper. At this time, the amount of toner on the paper was 1.20 mg / cm². 2 The DC voltage VDC of the developer carrier, the charging voltage VD of the electrostatic latent image carrier, and the laser power were adjusted accordingly. The process speed was adjusted to 120 A4 single-sided pages per minute. Evaluation images were output under low temperature and low humidity conditions (temperature 15°C / humidity 10%RH). The temperature on the fuser belt of the fuser unit was measured using a non-contact thermometer, and an evaluation image was output when the temperature reached 180°C. Subsequently, evaluation images were output while lowering the fuser unit's set temperature in 2°C increments, and the actual measured temperature on the fuser belt was confirmed when a gap (white dot) appeared in the evaluation image. The minimum temperature at which the white spots appeared plus 2°C was defined as the minimum temperature at which the fixation could occur, and the low-temperature fixation performance was evaluated according to the following criteria. (Evaluation Criteria) A: Minimum fixing temperature is less than 130°C B: Minimum fixing temperature is 130°C or higher, but less than 140°C. C: Minimum fixing temperature is 140°C or higher, but less than 150°C. D: Minimum fixing temperature is 150°C or higher

[0119] <Evaluation of hot offset resistance> The imagePRESS C10010VP fuser (manufactured by Canon) can operate independently. It was modified and used as an image forming apparatus. The fuser temperature was controlled in 2°C increments starting from 140°C. GFC-300 (A3 size, basis weight 81.4 g / m²) was used as the evaluation paper. 2 Using a Canon Marketing Japan Inc. printer, a 2cm x 5cm solid image was placed in the center of the paper, 1cm from the edge of the shorter side. At this time, the amount of toner on the paper was 0.10mg / cm². 2 The DC voltage VDC of the developer carrier, the electrostatic latent image carrier The charging voltage VD and laser power were adjusted. The process speed was adjusted to 120 A4 single-sided pages per minute. Evaluation images were output under normal temperature and low humidity conditions (temperature 23°C / humidity 5%RH). The temperature on the fuser belt of the fuser unit was measured using a non-contact thermometer, and an evaluation image was output when the temperature reached 140°C. Subsequently, evaluation images were output while increasing the fuser unit's set temperature in 2°C increments. The image density of the portion of the fixing belt that touched the evaluation image during output and then touched the evaluation paper again was measured using a white density meter (manufactured by Tokyo Denshoku Co., Ltd.). The measured temperature on the fixing belt at the point where the value was 0.5 higher than that of the white area was defined as the hot offset occurrence temperature. The temperature at which hot offset occurred minus 2°C was defined as the hot offset resistance temperature, and the hot offset resistance was evaluated according to the following criteria. (Evaluation Criteria) A: Hot offset temperature resistance of 220°C or higher B: Hot offset temperature tolerance between 210°C and below 220°C C: Hot offset tolerance temperature between 210°C and 200°C D: Hot offset temperature tolerance is less than 200°C In all of the above evaluation items, developer 1 received an A rating.

[0120] <Examples 2-14, Comparative Examples 1-4> (Manufacturing examples for toners 2-18) Except for changing the type and amount of binder resin and silica fine particles as shown in Table 3-1, toners 2 to 18 were obtained in the same manner as in the manufacturing example of toner 1. [Table 3-1] [Table 3-2]

[0121] In Table 3-2 above, "Specific Molecular Weight Content" refers to the content of components with a molecular weight of 4,000 to 50,000 relative to the tetrahydrofuran-soluble components obtained by dissolving toner in tetrahydrofuran. Furthermore, "Location of Silica Microparticles" refers to the percentage of silica microparticles located 0.3 μm or more from the surface of the toner particles. "Average Particle Size of Silica Microparticles" refers to the average particle size of silica microparticles contained within the toner particles.

[0122] (Manufacturing examples of developers 2-18) Developers 2-18 were obtained in the same manner as in the manufacturing example of developer 1, except that the toner was changed as shown in Table 4. Furthermore, they were evaluated in the same manner as developer 1. Examples 13 and 14 were evaluated as reference examples. The evaluation results are shown in Tables 4-1 and 4-2. [Table 4-1] [Table 4-2]

[0123] This disclosure relates to the following configuration. (Composition 1) A toner having toner particles containing a binder resin and silica fine particles, The tetrahydrofuran-soluble components obtained by dissolving the toner in tetrahydrofuran contain 50% by mass or more of components with a molecular weight of 4000 to 50000, based on the mass of the tetrahydrofuran-soluble components. The toner particles contain the silica fine particles in a region 0.3 μm or more inward from the surface. The solid sample is obtained by dissolving the toner particles in tetrahydrofuran and collecting the tetrahydrofuran-insoluble components. 29 In DD / MAS measurements of Si-NMR, the Si in the structure shown by the following formula (1) a The peak corresponding to the silicon atom shown, Si in the structure shown by equation (2) below. b The peaks corresponding to silicon atoms shown, and the Si in the structure shown by formula (3) below. cIt has a peak corresponding to the silicon atom shown, The Si a The area of ​​the peak corresponding to the silicon atom shown is defined as SD1, and the Si b The area of ​​the peak corresponding to the silicon atom shown is defined as SD2, and the Si c When SQ is the area of ​​the peak corresponding to the silicon atom shown, A toner characterized in that SD1, SD2, and SQ satisfy the following formulas (a) and (b). 0.050≦(SD1+SD2) / SQ (a) (SD1+SD2) / SD1≦25.0 (b) TIFF0007867856000015.tif107153 (In formulas (1) and (2), R independently represents a hydrogen atom, a methyl group, or an ethyl group.) (Configuration 2) The toner according to configuration 1, wherein SD1 and SD2 satisfy the following formula (c). (SD1+SD2) / SD1≦5.0 ···(c) (Composition 3) The toner according to configuration 1 or 2, wherein the silica fine particles are treated with at least one surface treatment agent selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, pentamethylcyclopentasiloxane, and dimethyldichlorosilane. (Composition 4) The toner according to any of configurations 1 to 3, wherein the number-average particle size of the silica fine particles is 5 to 300 nm. (Composition 5) The toner according to any one of configurations 1 to 4, wherein the content of the silica fine particles is 0.1 to 15.0 parts by mass per 100 parts by mass of the binder resin. (Composition 6) The toner according to any one of the configurations 1 to 5, wherein the acid value of the binder resin is 5.0 mg KOH / g or more.

Claims

1. A toner having toner particles containing a binder resin and silica fine particles, The tetrahydrofuran-soluble components obtained by dissolving the toner in tetrahydrofuran contain 50% by mass or more of components with a molecular weight of 4,000 to 50,000, based on the mass of the tetrahydrofuran-soluble components. The toner particles contain the silica fine particles in a region 0.3 μm or more inward from the surface. The solid sample is obtained by dissolving the toner particles in tetrahydrofuran and collecting the tetrahydrofuran-insoluble components. ２９ In Si-NMR DD / MAS measurements, the Si in the structure shown by the following formula (1) ａ The peak corresponding to the silicon atom shown, Si in the structure shown by the following formula (2) ｂ The peaks corresponding to silicon atoms shown, and the Si in the structure shown by formula (3) below. ｃ It has a peak corresponding to the silicon atom shown, The Si ａ Let SD1 be the area of ​​the peak corresponding to the silicon atom shown by the Si ｂ The area of ​​the peak corresponding to the silicon atom shown is defined as SD2, and the Si ｃ When SQ is the area of ​​the peak corresponding to the silicon atom shown, A toner characterized in that SD1, SD2, and SQ satisfy the following formulas (a) and (b). 0.050 ≤ (SD1 + SD2) / SQ ... Equation (a) 1.0≦(SD1+SD2) / SD1≦5.0 ...Formula (b) (In formulas (1) and (2), R independently represents a hydrogen atom, a methyl group, or an ethyl group.)

2. The toner according to claim 1, wherein the silica fine particles are treated with at least one surface treatment agent selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, pentamethylcyclopentasiloxane, and dimethyldichlorosilane.

3. The toner according to claim 1 or 2, wherein the number-average particle size of the silica fine particles is 5 to 300 nm.

4. The toner according to claim 1 or 2, wherein the content of the silica fine particles is 0.1 to 15.0 parts by mass per 100 parts by mass of the binder resin.

5. The toner according to claim 1 or 2, wherein the acid value of the binder resin is 5.0 mg KOH / g or more.

6. The toner according to claim 1 or 2, wherein the proportion of silica fine particles present in a region 0.3 μm or more inward from the surface of the toner particles is 30 to 100% of the total number of silica fine particles contained in the toner particles.

Images