Toner

Abstract

To provide a toner which offers superior low-temperature fixability and enables low-gloss, matte printing even on media having smooth printing surfaces.SOLUTION: A toner provided herein comprises toner particles containing a binder resin, non-magnetic inorganic oxide particles A, and magnetic iron oxide particles B. A softening point of a chloroform-soluble component of the toner particles is 90°C or less. The non-magnetic inorganic oxide particles A contain at least one element selected from a group consisting of Si, Mg, Al, Ti, and Sr as a main component. Among the non-magnetic inorganic oxide particles A with major axes of 100 nm or greater, a proportion of particles with major axes in a range of 400 to 3000 nm, inclusive, is 70% or more by number. Among the magnetic iron oxide particles B, particles with major axes in a range of 50 to 350 nm, inclusive, is 70% or more by number. A ratio of a number average particle major axis diameter of the non-magnetic inorganic oxide particles A to a number average particle major axis diameter of the magnetic iron oxide particles B is in a range of 5 to 30, inclusive.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a toner used in a recording method using an electrophotographic method or the like.

Background Art

[0002] In recent years, image forming apparatuses such as copiers and printers have been diversified in usage purposes and usage environments, and further high speed, high image quality, and high stability have been demanded. At the same time, in copiers and printers, miniaturization and energy saving of the apparatuses have been progressing, and a magnetic one-component development method using a magnetic toner, which is advantageous in these respects, is preferably used. In addition, among various printing usage purposes, there may be a case where it is necessary to cope with special media, and it is necessary to flexibly cope with individual needs.

[0003] In the electrophotographic method, there are a charging step of charging an electrostatic latent image carrier (hereinafter referred to as a photoreceptor) by a charging means, an exposure step of exposing the charged photoreceptor to form an electrostatic latent image, and a developing step of developing the electrostatic latent image with toner to form a toner image. Next, the toner image is transferred to a recording material with or without an intermediate transfer member, and the recording material carrying the toner image passes through a nip portion formed by a pressure member and a rotatable image heating member to be heat-pressed and fixed through a fixing step, and is output as an image.

[0004] In order to meet the recent demand for energy saving and to cope with a wide variety of usage purposes, it is necessary to perform sufficient fixing at a low temperature, and further, a toner having characteristics suitable for individual usage environments and purposes is required. In the case of monochrome printing, since the frequency of character printing is high, a matte texture with less gloss is preferred for printed matter. In addition, in order to cope with the diversification of usage purposes, a toner capable of performing high-quality character printing with low gloss on smooth media such as posters, labels, and films is required. Therefore, it is necessary to achieve both low-temperature fixability and low gloss.

[0005] Regarding the improvement of fixability, many techniques have been disclosed in the past. Among them, there are many related to plasticizers such as hydrocarbon waxes, ester waxes, and crystalline polyesters. Plasticizers enable fixing at low temperatures by making it easier to melt the toner binder. However, since they melt at low temperatures and have a lower viscosity, the surface of the printed image tends to become smooth and highly glossy. Generally, when the low-temperature fixability of toner is enhanced, it becomes easier to have a lower viscosity when heated, so the surface of the printed image tends to become smooth and highly glossy. To achieve both low-temperature fixability and low gloss, it is necessary to break this relationship between low viscosity and high gloss, which poses a technical challenge.

[0006] As related techniques, there has been disclosed a technique for improving image quality by adding inorganic particles such as silica and adjusting the toner viscosity (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, these techniques are insufficient for suppressing the smoothing of the toner that has been made less viscous to improve the low-temperature fixability. In particular, there is room for improvement to achieve both low-temperature fixability and low gloss for media with a smooth printed surface. The present disclosure provides a toner that has excellent low-temperature fixability and enables low-gloss and matte printing even on media with a smooth printed surface.

Means for Solving the Problems

[0009] ​The present disclosure relates to a toner having toner particles containing a binder resin, non-magnetic inorganic oxide particles A, and magnetic iron oxide particles B, wherein the softening point of the chloroform-soluble component of the toner particles is 90°C or lower, the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are internally added to the toner particles, the non-magnetic inorganic oxide particles A Silica particles, the content of the non-magnetic inorganic oxide particles A is 0.1 part by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the binder resin, the content of the magnetic iron oxide particles B is 50 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the binder resin, the number average value of the major axis of the non-magnetic inorganic oxide particles A is 400 nm or more and 3000 nm or less, the number average value of the major axis of the magnetic iron oxide particles B is 50 nm or more and 350 nm or less, among the non-magnetic inorganic oxide particles A having a major axis of 100 nm or more, the proportion of particles having a major axis of 400 nm or more and 3000 nm or less is 70% by number or more, among the magnetic iron oxide particles B, the proportion of particles having a major axis of 50 nm or more and 350 nm or less is 70% by number or more, the number average of the major axis of the magnetic iron oxide particles B Value with respect to Value the number average of the major axis of the non-magnetic inorganic oxide particles A, the toner has a ratio value of 5 or more and 30 or less.

Advantages of the Invention

[0010] According to the present disclosure, it is possible to provide a toner that is excellent in low-temperature fixability and enables low-gloss and matte printing even on media having a smooth printing surface.

Brief Description of the Drawings

[0011]

Figure 1

Embodiments for Carrying Out the Invention

[0012] In the present disclosure, unless otherwise specified, the description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the lower limit and the upper limit which are the endpoints. When numerical ranges are described stepwise, the upper limit and the lower limit of each numerical range can be arbitrarily combined.

[0013] The present disclosure relates to a toner having toner particles containing a binder resin, non-magnetic inorganic oxide particles A, and magnetic iron oxide particles B, wherein the softening point of the chloroform-soluble component of the toner particles is 90°C or lower, the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are incorporated into the toner particles, the non-magnetic inorganic oxide particles A contain at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr as a main component, among the non-magnetic inorganic oxide particles A having a major axis of 100 nm or more, the proportion of particles having a major axis of 400 nm or more and 3000 nm or less is 70% by number or more, among the magnetic iron oxide particles B, the proportion of particles having a major axis of 50 nm or more and 350 nm or less is 70% by number or more, relates to a toner in which the value of the ratio of the number average particle diameter of the major axis of the non-magnetic inorganic oxide particles A to the number average particle diameter of the major axis of the magnetic iron oxide particles B is 5 or more and 30 or less.

[0014] The present inventors have intensively studied to achieve both low gloss, which is contrary to low-temperature fixing accompanied by low viscosity of the toner in monochrome printing. To achieve low-temperature fixability of the toner, for example, a binder resin having a low softening point is contained. Also, a crystalline material such as an ester compound may be contained as a plasticizer to lower the softening point of the binder resin. Such toner particles having a low softening point melt at a lower temperature and have a lower viscosity, so they are excellent in low-temperature fixability.

[0015] However, the toner particles with reduced viscosity are highly responsive to the pressure during fixing and tend to spread, so the surface tends to become smooth during fixing. In rubber materials such as tires, a method of mixing fine particles such as carbon as a filler to increase the viscosity and strength is known. Similarly, in the case of toner, the viscosity of the toner can be increased and the strength can be increased by containing inorganic fine particles such as silica as described in the above literature. However, the fixability is inhibited accordingly. Thus, there are technical problems in reducing the softening point of the toner particles to achieve low-temperature fixing and further reducing the gloss to maintain the monochrome character quality.

[0016] Therefore, the present inventors have found that by containing two types of particles, non-magnetic inorganic oxide particles with a large particle size and magnetic iron oxide particles which are nanoparticles smaller than the non-magnetic inorganic oxide particles but relatively large, low-temperature fixing and low-glossification can be achieved.

[0017] Hereinafter, the toner will be described. The toner particles contain non-magnetic inorganic oxide particles A and magnetic iron oxide particles B. The non-magnetic inorganic oxide particles A contain at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr as a main component. Note that the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are contained in the toner particles. That is, these particles are mixed with the binder resin in the toner manufacturing process and are in a state of being internally added inside the toner particles when they become toner. For example, the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are dispersed in the binder resin. It is preferable that the internally added particles are uniformly dispersed inside the toner particles.

[0018] From the viewpoint of low-temperature fixability, the softening point of the chloroform-soluble component of the toner particles needs to be 90°C or lower. The softening point is preferably 55°C or higher and 85°C or lower, and more preferably 60°C or higher and 80°C or lower.

[0019] Toner particles with a softening point of the chloroform-soluble component of 90°C or lower can be fixed at a low temperature during the fixing process. However, since they tend to have a low viscosity, the gloss of the fixed image increases. Therefore, the value of the ratio of the number-average particle diameter of the major axis (non-magnetic inorganic oxide particles A / magnetic iron oxide particles B) is set to 5 or more and 30 or less. Further, among the non-magnetic inorganic oxide particles A of 100 nm or more, the non-magnetic inorganic oxide particles A having a major axis of 400 nm or more and 3000 nm or less are 70% or more by number, and among the magnetic iron oxide particles B, the magnetic iron oxide particles B having a major axis of 50 nm or more and 350 nm or less are 70% or more by number. It has been found that by doing so, while maintaining low-temperature fixability, the gloss of the fixed image can be reduced.

[0020] Regarding this, the considerations of the present inventors will be described. For example, here, particles with a particle size of less than about 50 nm are defined as small-diameter particles, particles with a particle size of 50 nm or more and less than 400 nm are defined as medium-diameter particles, and particles with a particle size of 400 nm or more are defined as large-diameter particles. As described above, during fixing, the toner has a reduced viscosity, spreads easily, and becomes fluid. The presence of medium-diameter magnetic iron oxide particles here suppresses the fluidity of the toner binder. Further, the presence of large-diameter non-magnetic inorganic oxide particles there forms convex portions in the fixed image starting from the large-diameter particles. Due to the convexity, the image surface becomes rough, and the gloss is reduced by light scattering, so that a matte texture can be obtained.

[0021] In order to exhibit an appropriate viscosity suppressing effect and not inhibit fixing, the ratio of particles having a major axis of 50 nm or more and 350 nm or less among the magnetic iron oxide particles B is 70% or more by number. Further, since the magnetic iron oxide particles attract each other with a minute force due to the action of the residual magnetization, the suppression of fluidization can be effectively achieved, and fixing is not inhibited.

[0022] Among the magnetic iron oxide particles B, the ratio of particles having a major axis of 50 nm or more and 350 nm or less is 75% by number It is preferably from more than [[ID=]]% to 100% by number, more preferably from 78% to 90% by number, and even more preferably from 78% to 85% by number. The percentage by number of particles having a major axis of 50 nm or more and 350 nm or less in the magnetic iron oxide particles B can be controlled by adjusting the reaction conditions for promoting the oxidation reaction in the process of generating the iron oxide particles.

[0023] The non-magnetic inorganic oxide particles A are oxide particles mainly composed of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr, which are less likely to inhibit electrophotographic characteristics. Here, the main component means that among the atoms excluding carbon and oxygen contained in the inorganic oxide, those exceeding 50 atomic% are the main components. For example, it is at least one selected from the group consisting of SiO2, TiO2, MgO, Al2O3, and SrTiO3. Preferably, they are oxide particles containing Si. Among them, silica particles are more preferable. The silica particles do not inhibit electrophotographic characteristics, and due to the intermolecular force between the hydroxyl groups on the surface and the resin, the silica particles are less likely to be exposed on the surface of the fixed image.

[0024] In addition, in order to form convex portions on the fixed image and achieve low gloss while maintaining good low-temperature fixability, the ratio of particles having a major axis of 400 nm or more and 3000 nm or less among the non-magnetic inorganic oxide particles A of 100 nm or more is 70% or more by number.

[0025] The ratio of particles having a major axis of 400 nm or more and 3000 nm or less among the non-magnetic inorganic oxide particles A of 100 nm or more is preferably from 75% to 100% by number, more preferably from 80% to 98% by number, and even more preferably from 85% to 97% by number. The percentage by number of particles having a major axis of 400 nm or more and 3000 nm or less can be controlled by adjusting the pulverization intensity and time in the process of pulverizing the particles.

[0026] More preferably, in order to effectively form the convex portions, the proportion of particles having a major axis length of 800 nm or more and 3000 nm or less among the non-magnetic inorganic oxide particles A of 100 nm or more is preferably 70% by number or more. The proportion of particles having a major axis length of 800 nm or more and 3000 nm or less among the non-magnetic inorganic oxide particles A of 100 nm or more is preferably 75% by number or more and 100% by number or less, more preferably 80% by number or more and 95% by number or less, and even more preferably 85% by number or more and 92% by number or less. The percentage of particles having a major axis length of 800 nm or more and 3000 nm or less can be controlled by adjusting the pulverization intensity and time in the step of pulverizing the particles.

[0027] In addition, the value of the ratio of the number average particle diameter of the major axis of the non-magnetic inorganic oxide particles A to the number average particle diameter of the major axis of the magnetic iron oxide particles B (non-magnetic inorganic oxide particles A / magnetic iron oxide particles B) is preferably set to 5 or more and 30 or less, which is optimal for effectively forming the convexes without inhibiting the fixing. The value of the ratio is preferably 7 or more and 25 or less, and more preferably 8 or more and 20 or less.

[0028] The number average particle diameter of the major axis of the non-magnetic inorganic oxide particles A is preferably 400 nm or more and 3000 nm or less, more preferably 800 nm or more and 2800 nm or less, and even more preferably 1200 nm or more and 2600 nm or less. In addition, the number average particle diameter of the major axis of the magnetic iron oxide particles B is preferably 50 nm or more and 350 nm or less, more preferably 100 nm or more and 250 nm or less, and even more preferably 120 nm or more and 200 nm or less.

[0029] The softening point of the chloroform-soluble component of the toner is the softening point measured by thermomechanical analysis (hereinafter referred to as TMA). The external additive of the toner is ultrasonically dispersed and removed in an aqueous surfactant solution to obtain toner particles. The toner particles are dissolved in chloroform, and after removing the magnetic iron oxide particles using a magnet, the chloroform-insoluble matter is further separated and removed using a centrifuge to obtain a chloroform solution. The chloroform is evaporated with an evaporator, and the chloroform is completely removed by a vacuum dryer to obtain the chloroform-soluble component of the toner.

[0030] Take 20 mg of the obtained chloroform-soluble component and make it into a pellet with a diameter of 5 mmφ and a thickness of 1 mm under 5 kN, and perform TMA measurement. The TMA measurement is carried out using a Q400 manufactured by TA Instrument. The measurement is performed from 30 °C to 150 °C under the temperature rising condition of 0.1 N and 10 °C / min with a probe diameter of 2.8 mmφ. From the obtained displacement curve data, the intersection point of the original baseline and the tangent line after displacement is defined as the softening point (Figure 1). The softening point can be achieved by optimally designing the molecular weight of the binder resin. In particular, it is possible to lower the softening point by containing a large amount of low molecular weight components.

[0031] The means for obtaining toner particles by removing the external additive from the toner are as follows. Put 6 mL of Contaminon N (a 10 mass% aqueous solution of a neutral detergent for precision measuring instrument cleaning with pH 7 composed of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) into 100 mL of ion-exchanged water to prepare a dispersion medium. Add 5 g of toner to this dispersion medium and disperse it with an ultrasonic disperser (VS-150 manufactured by AS ONE Corporation) for 5 minutes. Then, set it on a "KM Shaker" (model: V.SX) manufactured by Iwaki Sangyo Co., Ltd. and shake it for 20 minutes under the condition of 350 reciprocations per minute. Then, restrain and collect the toner particles using a neodymium magnet.

[0032] The particle size measurement of magnetic iron oxide particles B is carried out as follows. Remove the external additive of the toner by the method described above to obtain toner particles. Dissolve the toner particles in chloroform and recover the magnetic iron oxide particles using a magnet. Heat the obtained magnetic iron oxide particles at 800 °C for 30 minutes using an electric furnace or TGA to decompose the remaining organic components. Recover the remaining magnetic iron oxide particles and perform SEM observation and EDX analysis. The observation magnification is 10,000 times. Confirm by EDX analysis that the particles are composed of iron and oxygen, and obtain the major axis of the particles using image processing software. Measure 200 particles, confirm the distribution of the major axis, and calculate the percentage of the number of particles existing in the range of 50 nm to 350 nm. Also, calculate the number average particle size from the average value of the major axes of 200 particles. Details will be described later.

[0033] The particle size measurement of non-magnetic inorganic oxide particles A is described below. The external additive of the toner is removed by the method described above to obtain toner particles. The toner particles are dissolved in chloroform, and magnetic iron oxide particles are removed using a magnet. The solid obtained by evaporating chloroform with an evaporator is heated at 800 °C for 30 minutes using an electric furnace or TGA to decompose the remaining organic components. The remaining non-magnetic inorganic oxide particles A are recovered, and SEM observation and EDX analysis are performed. Observation magnification is 10,000 times, and it is confirmed by EDX analysis that the particles are composed of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr and oxygen. The major axis of the particles is determined using image processing software. Fifty particles are measured, the major axis distribution is confirmed, and the percentage of the number of particles present in the range of 400 nm to 3000 nm and the percentage of the number of particles present in the range of 800 nm to 3000 nm are calculated. Also, the number average particle size is calculated from the average value of the major axes of 50 particles. Details will be described later.

[0034] The manufacturing method of non-magnetic inorganic oxide particles A is not particularly limited, and known methods can be adopted. In particular, as a method for manufacturing silica particles, there are a vapor phase method in which a silicon compound such as metallic silicon, silicon halide, and silane compound is reacted in the gas phase, and a wet method in which a silane compound such as alkoxysilane is hydrolyzed and subjected to a condensation reaction. For silica particles, the manufacturing method can be selected without restriction. In the production of relatively large silica particles having a major axis of 400 nm or more and 3000 nm or less, a vapor phase oxidation method in which a powder raw material is directly oxidized by a chemical flame composed of oxygen and hydrogen is preferably used. The vapor phase oxidation method can instantaneously raise the inside of the reaction vessel to a temperature equal to or higher than the melting point of the inorganic fine powder, and is a preferable manufacturing method for obtaining large silica particles.

[0035] For example, silica particles can be obtained by producing silica particles of about 3000 to 5000 nm by the vapor phase oxidation method as described above and pulverizing them by a known method to obtain silica particles of the desired size and shape. As the pulverizer, for example, when using a device with high pulverizing ability such as a parabolizer or a jet mill, it is easy to control the shape and particle size. Also, appropriately, a known classification device can be used to adjust the particle size distribution.

[0036] Similarly, the manufacturing method for oxide particles of Mg, Al, Ti, and Sr can be selected without any restrictions. For example, oxides are produced by purification or synthesis using minerals as raw materials, and are adjusted to the desired size and shape by performing pulverization and classification as necessary.

[0037] The manufacturing method of magnetic iron oxide particles B is not particularly limited either, and can be manufactured, for example, by the following method. An alkali such as sodium hydroxide equivalent to or more than the equivalent of the iron component is added to an aqueous solution of ferrous salt to prepare an aqueous solution containing ferrous hydroxide. While maintaining the pH of the prepared aqueous solution at pH 7 or higher, air is blown in, and the oxidation reaction of ferrous hydroxide is carried out while heating the aqueous solution to 70°C or higher to first generate seed crystals that will form the core of the magnetic iron oxide particles.

[0038] Next, an aqueous solution containing approximately 1 equivalent of ferrous sulfate based on the amount of alkali added previously to the slurry-like liquid containing the seed crystals is added. While maintaining the pH of the liquid at 5 - 10, air is blown in and the reaction of ferrous hydroxide is advanced to grow magnetic iron oxide with the seed crystals as the core. At this time, by selecting arbitrary pH, reaction temperature, and stirring conditions, and adding additives as necessary, it is possible to control the shape and magnetic properties of the magnetic iron oxide particles. As the oxidation reaction proceeds, the pH of the liquid shifts to the acidic side, but it is preferable that the pH of the liquid does not become less than 5. The magnetic iron oxide particles thus obtained can be filtered, washed, and dried by a conventional method to obtain magnetic iron oxide particles.

[0039] Examples of the magnetic iron oxide particles include magnetite, maghemite, ferrite, etc., or alloys of these with metals such as silica, aluminum, copper, magnesium, tin, zinc, beryllium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.

[0040] Examples of the shape of the magnetic iron oxide particles include octahedron, hexahedron, spherical, needle-like, and flaky, etc., and any of them can be used, but preferably a polyhedron with 4 or more faces, more preferably a polyhedron structure with 8 or more faces.

[0041] In addition, the content of the magnetic iron oxide particles B is preferably 50 to 150 parts by mass, more preferably 60 to 120 parts by mass, based on 100 parts by mass of the binder resin, in order to optimally maintain the electrophotographic properties. The content of the non-magnetic inorganic oxide particles A is preferably 0.1 to 5.0 parts by mass, more preferably 0.3 to 3.0 parts by mass, and even more preferably 0.5 to 2.5 parts by mass, based on 100 parts by mass of the binder resin.

[0042] It is also preferable to adjust the residual magnetization (σr) as the magnetic property of the magnetic iron oxide particles B. The residual magnetization (σr) of the magnetic iron oxide particles B is preferably 2 Am 2 / kg to 24 Am 2 / kg, more preferably 4 Am 2 / kg to 18 Am 2 / kg, and even more preferably 6 Am 2 / kg to 10 Am 2 / kg. By adjusting σr to a lower value, the toner is well dispersed and scattered during development, which is effective for low-temperature fixing. As a method for adjusting σr, it is good to add Si. In order to optimally set σr, the Si content in the magnetic iron oxide particles B is preferably 0.5 to 3 mass%.

[0043] In addition, by adjusting the ratio of the content of the non-magnetic inorganic oxide particles A to the content of the magnetic iron oxide particles B, it is easy to achieve low-temperature fixability and low gloss. Specifically, in the observation by a transmission electron microscope of the cross-section of the toner cut with a microtome, the value of the ratio of the number of magnetic iron oxide particles B to the number of non-magnetic inorganic oxide particles A contained in the cross-section of the toner particles (magnetic iron oxide particles B / non-magnetic inorganic oxide particles A) is preferably 50 to 500. More preferably 100 ~400, and even more preferably 150 to 300.

[0044] Furthermore, in the observation by a transmission electron microscope of the cross-section of the toner cut with a microtome, it is preferable that the non-magnetic inorganic oxide particles A are present in an amount of 0.5 to 5.0 per cross-section of the toner. More preferably, it is 0.7 to 3.0, and still more preferably, it is 0.8 to 1.5. Thereby, protrusions are effectively formed on the surface of the fixed image, and it becomes easier to achieve low-temperature fixability and low gloss. Also, by setting it to 5.0 or less, it is easy to suppress defective fixed images due to peeling of the convex portions.

[0045] Also, in the observation by a transmission electron microscope of the cross-section of the toner cut with a microtome, it is preferable that 100 to 500 magnetic iron oxide particles B are present per cross-section of the toner, more preferably 120 to 450 are present, and still more preferably 200 to 400 are present.

[0046] As the shape of the particles, the non-magnetic inorganic oxide particles A are preferably irregularly shaped, and the magnetic iron oxide particles B are preferably closer to spherical shapes such as spherical, octahedral, and hexahedral. Specifically, in the observation by a transmission electron microscope of the cross-section of the toner cut with a microtome, it is preferable that the shape factor SF1 of the non-magnetic inorganic oxide particles A is 140 or more, and the shape factor SF1 of the magnetic iron oxide particles B is 110 or less. The shape factor SF1 of the non-magnetic inorganic oxide particles A is more preferably 143 or more and 160 or less, and still more preferably 147 or more and 155 or less. The shape factor SF1 of the magnetic iron oxide particles B is more preferably 100 or more and 109 or less, and still more preferably 102 or more and 107 or less.

[0047] By controlling the shape in this way, it becomes easier to achieve the effects of low-temperature fixability and low gloss. That is, by making the non-magnetic inorganic oxide particles A irregular in shape, the magnetic iron oxide particles B present above the non-magnetic inorganic oxide particles A in the fixing process are less likely to flow down under the non-magnetic inorganic oxide particles A due to being caught by the irregular parts, so they can form convex shapes while being wrapped in the resin. That is, it is possible to suppress the exposure of the non-magnetic inorganic oxide particles A in the fixed image and the fixing failure due to peeling starting from the non-magnetic inorganic oxide particles A. The shape factor SF1 of the non-magnetic inorganic oxide particles A can be controlled by adjusting the pulverization strength and time in the process of pulverizing the particles. Also, the shape factor SF1 of the magnetic iron oxide particles B can be controlled by adjusting the reaction conditions for promoting the oxidation reaction in the process of generating the iron oxide particles.

[0048] The toner contains a binder resin. The binder resin is not particularly limited, and known materials such as vinyl resins and polyester resins can be used. Specifically, styrene copolymers such as polystyrene, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polyacrylate esters, polymethacrylate esters, polyvinyl acetate, etc. can be used, and these can be used alone or in combination of multiple types.

[0049] Preferably, the binder resin contains an amorphous polyester resin. Thereby, material design for low-temperature fixing is relatively easy, and the interaction between the resin and the non-magnetic inorganic oxide particles A is likely to be exerted also with respect to the convex formation on the image surface. Further, the content ratio of the amorphous polyester resin in the binder resin is preferably 50% by mass or more, more preferably 75% by mass to 100% by mass, and still more preferably 90% by mass to 100% by mass. Thereby, the above action is more likely to be obtained.

[0050] As the amorphous polyester resin, a normal one composed of an alcohol component and an acid component can be used, and examples of both components are shown below. Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexenedimethanol, hydrogenated bisphenol A, or a bisphenol derivative represented by the formula (A); a hydrogenated product of the compound represented by the formula (A), a diol represented by the formula (B), or a diol of a hydrogenated product of the compound of the formula (B).

[0051] [Chemical formula] [In the formula, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10.]

[0052] [Chemical formula]

[0053] Examples of the divalent acid component include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride or their anhydrides; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or their anhydrides; succinic acid or its anhydride substituted with an alkyl or alkenyl group having 6 to 18 carbon atoms; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid or their anhydrides, etc. Furthermore, examples of the trivalent or higher alcohol component include glycerin, pentaerythritol, sorbitol, sorbitan, oxyalkylene ethers of novolak type phenol resins, and examples of the trivalent or higher acid component include trimellitic acid, pyromellitic acid, 1,2,3,4 - butanetetracarboxylic acid, benzophenone tetracarboxylic acid and its anhydride, etc.

[0054] The softening point of the chloroform - soluble component of the toner particles can be controlled by the design of the binder resin. For example, the softening point can be controlled by adjusting the cross - linking density or the molecular weight, but preferably it is controlled by the content of the low - molecular - weight component. The low - molecular - weight component can be confirmed by the number - average molecular weight (Mn) obtained by GPC measurement. In order to more fully exhibit the low - temperature fixability, the number - average molecular weight (Mn) of the binder resin is preferably 1000 to 5000, more preferably 1300 to 3000. Also, the weight - average molecular weight (Mw) of the binder resin is preferably 30000 to 80000, more preferably 45000 to 60000.

[0055] A charge - control agent may be added to the toner. As the charge - control agent for negative charging, organometallic complex compounds and chelate compounds are effective, and examples include monoazo metal complex compounds; acetylacetone metal complex compounds; metal complex compounds of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids, etc. Specific examples of commercially available products include Spilon Black TRH, T - 77, T - 95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S - 34, S - 44, S - 54, E - 84, E - 88, E - 89 (Orient Chemical Industries).

[0056] The toner may contain crystalline materials such as ester wax and hydrocarbon wax as release agents. The crystalline material also participates in improving the fixing property as a plasticizer. As the release agent, any known release agent can be used.

[0057] Specifically, examples of the hydrocarbon wax include the following: paraffin wax, microcrystalline wax, petroleum waxes such as petrolatum and their derivatives, hydrocarbon waxes and their derivatives obtained by the Fischer-Tropsch method, polyolefin waxes such as polyethylene and polypropylene and their derivatives, and the like. Alternatively, it is montan wax and its derivatives, carnauba wax, candelilla wax and other natural waxes and their derivatives, ester waxes mainly composed of fatty acid esters, and the like. In addition to monofunctional ester waxes, polyfunctional ester waxes such as difunctional, tetrafunctional and hexafunctional ester waxes can also be used. Specifically, examples include diester compounds of saturated aliphatic dicarboxylic acids and saturated aliphatic alcohols such as dibehenyl sebacate, distearyl dodecanedioate, distearyl octadecanedioate; diester compounds of saturated aliphatic diols and saturated fatty acids such as nonanediol dibehenate, dodecanediol distearate; triester compounds of trialcohols such as glycerin tribehenate, glycerin tristearate and saturated fatty acids; partial ester compounds of trialcohols such as glycerin monobehenate, glycerin dibehenate and saturated fatty acids; and the like.

[0058] Preferably, the release agent is at least one selected from the group consisting of hydrocarbon wax and ester wax. In order to optimally maintain the low-temperature fixing property, the content of the release agent is preferably 3 parts by mass or more and 20 parts by mass or less, more preferably 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0059] As a plasticizer for improving fixability, the toner particles preferably contain a crystalline polyester resin. The crystalline polyester has high compatibility with the binder resin and quickly reduces the viscosity of the toner at low temperatures. The crystalline polyester resin is preferably a condensate of an aliphatic diol and an aliphatic dicarboxylic acid from the viewpoints of crystallization in the binder resin and plasticizing ability during fixing. The aliphatic diol and the aliphatic dicarboxylic acid may be selected from those having 4 to 16 carbon atoms. Thereby, it is easy to balance fixability and storage stability. The content of the crystalline polyester resin is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0060] As the crystalline polyester resin, those produced by known synthesis methods can be used. For example, it can be obtained by subjecting a dicarboxylic acid component and a diol component to an esterification reaction or a transesterification reaction, and then performing a polycondensation reaction under reduced pressure or by introducing nitrogen gas according to a conventional method.

[0061] At the time of the esterification or transesterification reaction, ordinary esterification catalysts or transesterification catalysts such as sulfuric acid, tertiary butyl titanate, dibutyltin oxide, manganese acetate, and magnesium acetate can be used as necessary. Regarding the polymerization, ordinary polymerization catalysts, for example, known ones such as tertiary butyl titanate, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, and germanium dioxide can be used. The polymerization temperature and the amount of catalyst are not particularly limited and can be arbitrarily selected as necessary.

[0062] The toner may contain toner particles and an external additive on the surface of the toner particles. Examples of the external additive include known ones. Examples of the external additive include metal oxide fine particles (inorganic fine particles) such as silica fine particles, alumina fine particles, titania fine particles, zinc oxide fine particles, strontium titanate fine particles, cerium oxide fine particles, and calcium carbonate fine particles.

[0063] In the toner, other additives can be further used within a range that does not substantially have an adverse effect, such as lubricant powders such as fluororesin powder, zinc stearate powder, and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder, and strontium titanate powder; fluidity improvers such as titanium oxide powder and aluminum oxide powder; anti-caking agents; or a small amount of organic and inorganic fine particles with opposite polarity can be used as a developability improver. It is also possible to use these additives after hydrophobically treating their surfaces.

[0064] The weight average particle diameter (D4) of the toner is preferably 3.0 μm or more and 12.0 μm or less, more preferably 4.0 μm or more and 10.0 μm or less. When the weight average particle diameter (D4) is within the above range, good fluidity can be obtained and it can develop faithfully to the latent image.

[0065] In addition, the value of the ratio of the weight average particle diameter of the toner to the number average particle diameter of the major axis of the non-magnetic inorganic oxide particles A (toner / non-magnetic inorganic oxide particles A) is preferably 2 or more and 15 or less, more preferably 2 or more and 10 or less, and even more preferably 3 or more and 7 or less. By being within this range, while minimizing the influence on physical properties that affect electrophotographic properties such as developability and chargeability including fixability, the formation of protrusions on the image surface during fixing can be realized more effectively.

[0066] The method for manufacturing the toner is not particularly limited, and a known manufacturing method can be adopted. Examples of the method for manufacturing the toner include a pulverization method, a polymerization method, such as a dispersion polymerization method, an association aggregation method, a dissolution suspension method, a suspension polymerization method, and an emulsion aggregation method. Hereinafter, a pulverization method for manufacturing a toner through a melt-kneading step and a pulverization step will be specifically exemplified, but it is not limited thereto.

[0067] For example, a binder resin, magnetic iron oxide particles B, non-magnetic inorganic oxide particles A, and, if necessary, a colorant, a release agent, a charge control agent, and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill (mixing step). The obtained mixture is melt-kneaded using a heat-kneading machine such as a twin-screw kneading extruder, a heating roll, a kneader, or an extruder (melt-kneading step).

[0068] After the obtained melt-kneaded product is cooled and solidified, it is pulverized using a pulverizer (pulverizing step), and classified using a classifier (classification step) to obtain toner particles. The toner particles may be used as toner as they are. If necessary, the toner particles and an external additive may be mixed by a mixer such as a Henschel mixer to obtain toner.

[0069] Examples of the mixer include the following: FM mixer (manufactured by Nippon Coke Industry Co., Ltd.); Super mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Seisakusho Co., Ltd.); Nauta mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Corporation); Spiral Pin mixer (manufactured by Taiheiyo Kiko Co., Ltd.); Lodige mixer (manufactured by Matsubo Corporation).

[0070] Examples of the heat-kneading machine include the following: KRC kneader (manufactured by Kurimoto Iron Works Co., Ltd.); Bus Ko kneader (manufactured by Buss Co., Ltd.); TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works, Ltd.); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho Co., Ltd.); Needex (manufactured by Mitsui Mining Co., Ltd.); MS type pressure kneader, Nidaluder (manufactured by Moriyama Seisakusho Co., Ltd.); Banbury mixer (manufactured by Kobe Steel, Ltd.).

[0071] Examples of crushers include: Counter Jet Mill, Micron Jet, Inomizer (manufactured by Hosokawa Micron Corporation); IDS Mill, PJM Jet Crusher (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross Jet Mill (manufactured by Kurimoto Iron Works, Ltd.); Ulmax (manufactured by Nippon Catalytic Chemical Industries, Ltd.); SK Jet-Oh-Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Industries Co., Ltd.); Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0072] Examples of classifiers include: Classier, Micron Classifier, Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turbo Preplex (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.); YM Micro Cut (manufactured by Yaskawa Shoji Co., Ltd.).

[0073] In addition, the following screening devices may be used to separate coarse particles: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonaceb, Gyro Shifter (manufactured by Tokuju Kousakusho); Vibra Sonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shin Dong Industries Co., Ltd.); Turbo Screener (manufactured by Turbo Industries Co., Ltd.); Micro Shifter (manufactured by Makino Sangyo Co., Ltd.); Circular Vibrating Screen.

[0074] Next, the measurement methods for each physical property will be described. <Measurement of Softening Point of Chloroform-Soluble Content> Remove the external additives of the toner by the method described above to obtain toner particles. Dissolve the toner particles in chloroform, remove the magnetic iron oxide particles using a magnet, and then further separate and remove the insoluble matter using a centrifuge to obtain a chloroform solution of the toner particles. Evaporate the chloroform with an evaporator, and further remove the chloroform completely with a vacuum dryer to obtain the chloroform-soluble components of the toner particles. Take 20 mg of the obtained chloroform-soluble components and form a pellet with a diameter of 5 mmφ and a thickness of 1 mm at 5 kN, and perform TMA measurement. The TMA measurement is carried out using a Q400 manufactured by TA Instrument, using a probe with a diameter of 2.8 mmφ, and measuring from 30°C to 150°C under the temperature rising condition of 0.1 N and 10°C / min. The softening point is defined as the intersection point between the original baseline and the tangent line after displacement from the obtained displacement curve data (Figure 1).

[0075] <Composition Analysis and Particle Size Measurement of Magnetic Iron Oxide Particles B> The particle size measurement of the magnetic iron oxide particles B is carried out as follows. Remove the external additives of the toner by the method described above to obtain toner particles. Dissolve the toner particles in chloroform and recover the magnetic iron oxide particles using a magnet. Heat the obtained iron oxide particles at 800°C for 30 minutes using an electric furnace to decompose the remaining organic components. Recover the remaining iron oxide particles and perform scanning electron microscope (SEM) observation and energy dispersive X-ray analyzer (EDX) analysis. The observation magnification is 10,000 times, and it is confirmed by EDX analysis that the particles are composed of iron and oxygen (including trace elements such as Si if necessary), and the major axis is obtained for the particles using image processing software. Measure 200 particles, confirm the distribution of the major axis, and calculate the percentage of the number of particles existing in the range of 50 nm to 350 nm. Also, calculate the number average particle size from the average value of 200 particles. SEM: JEOL, JSM7800 EDX: Thermo Fisher Scientific, Talos F200X Image processing software: Image analysis device (Luzex AP) manufactured by Nireco

[0076] <Composition Analysis and Particle Size Measurement of Non-Magnetic Inorganic Oxide Particles A> The particle size measurement of non-magnetic inorganic oxide particles A is described below. The external additive of the toner is removed by the above method to obtain toner particles. The toner particles are dissolved in chloroform, and the magnetic iron oxide particles are removed using a magnet. The solid obtained by evaporating chloroform with an evaporator is heated at 800 °C for 30 minutes using an electric furnace to decompose the remaining organic components. The remaining non-magnetic inorganic oxide particles A are recovered, and SEM observation and EDX analysis are performed. Observation magnification is 10,000 times, and it is confirmed by EDX analysis that the particles are composed of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr and oxygen. Also, from the EDX spectrum, it is confirmed that the above elements are the main components by exceeding 50 atomic% of the peaks of the above elements with respect to the total sum of the peaks excluding carbon and oxygen. The major axis is determined for the confirmed particles using image processing software. Fifty particles are measured to confirm the major axis distribution, and the percentage of particles with a major axis of 400 nm to 3000 nm and the percentage of particles with a major axis of 800 nm to 3000 nm among the particles with a major axis of 100 nm or more are calculated. Also, the number average particle size is calculated from the average value of the 50 particles. Qualitative analysis by an X-ray diffractometer (XRD) is also performed to confirm that it is an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr. SEM: JEOL, JSM7800 EDX: Thermo Fisher Scientific, Talos F200X Image processing software: Image analyzer (Luzex AP) manufactured by Nireco XRD: Rigaku, RINT-TTR III

[0077] <Measurement method for the number and shape factor of non-magnetic inorganic oxide particles A and magnetic iron oxide particles B> The non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are internal additive particles contained in the toner particles before going through the external addition process. The externally added particles can be removed by the method described above. The number of the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B refers to the number calculated based on the cross-sectional image of the toner particles observed by a transmission electron microscope (TEM), and the shape factor is also calculated based on this image. The cross-sectional image of the toner particles by a transmission electron microscope (TEM) is prepared as follows. Using an osmium plasma coater (Filgen, OPC80T), an Os film (5 nm) and a naphthalene film (20 nm) are applied to the toner as a protective film, and after embedding with a photocurable resin D800 (JEOL), a cross-section of the toner particles with a film thickness of 60 nm (or 70 nm) is prepared at a cutting speed of 1 mm / s by an ultrasonic ultramicrotome (Leica, UC7). The obtained cross-section is subjected to STEM observation using the STEM function of a TEM (JEOL, JEM2800). The probe size of the STEM is 1 nm, and the image size is acquired at 1024×1024 pixels. Among the cross-sections of the toner particles, a cross-section having a diameter of 0.9 times to 1.1 times the weight average particle diameter is selected.

[0078] The obtained image is introduced into an image processing software, an image analyzer (Luzex AP) manufactured by Nireco, for analysis to calculate the number and shape factor of the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B. The shape factor SF1 is taken as the value obtained by calculating according to the following formula (1). SF1=(L 2 / A)×(π / 4)×100 ···(1) In the formula, L represents the absolute maximum length (length of the circumscribed circle) of the particle, P represents the perimeter of the particle, and A represents the projected area of the particle. In the calculation of the number and the shape factor, it is calculated by observing and analyzing the cross-sections of 100 toner particles. For the shape factor, the number of non-magnetic inorganic oxide particles A per toner particle, and the number of magnetic iron oxide particles B per toner particle, their arithmetic mean values are adopted. The distinction between the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B can be made by EDX analysis. The non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are internal additive particles contained in the toner particles before going through the external addition process. The externally added particles can be removed by the method described above. The number of the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B refers to the number calculated based on the cross-sectional image of the toner particles observed by a transmission electron microscope (TEM), and the shape factor is also calculated based on this image. The cross-sectional image of the toner particles by a transmission electron microscope (TEM) is prepared as follows.

[0079] <Measurement of Weight Average Particle Size (D4) and Number Average Particle Size (D1) of Toner (Particles)> The weight average particle size (D4) and number average particle size (D1) of the toner (particles) are measured with a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube and the dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) attached for measurement condition setting and measurement data analysis, and measured with an effective measurement channel number of 25,000 channels, and the measurement data is analyzed and calculated. The electrolytic aqueous solution used for measurement is a solution prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of about 1% by mass. For example, "ISOTON II" (manufactured by Beckman Coulter, Inc.) can be used. Before performing measurement and analysis, the settings of the dedicated software are made as follows.

[0080] On the "Change Screen of Standard Measurement Method (SOM)" of the dedicated software, set the total count number in the control mode to 50,000 particles, the number of measurements to 1 time, and set the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter, Inc.). By pressing the measurement button for threshold / noise level, the threshold and noise level are automatically set. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the flash of the aperture tube after measurement. On the "Conversion Setting Screen from Pulse to Particle Size" of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

[0081] The specific measurement method is as follows. (1) Pour approximately 200 ml of the electrolytic aqueous solution into a 250 ml round-bottom glass beaker dedicated to the Multisizer 3, set it on the sample stand, and stir with a stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture tube flash" function of the dedicated software to remove dirt and bubbles in the aperture tube. (2) Pour approximately 30 ml of the electrolytic aqueous solution into a 100 ml flat-bottom glass beaker, and add approximately 0.3 ml of a dilution obtained by diluting "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for precision measuring instrument cleaning with pH 7 composed of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) 3 times by mass with ion-exchanged water as a dispersant. (3) Place a predetermined amount of ion-exchanged water in the water tank of an ultrasonic disperser "Ultrasonic Dispersion System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.) with a built-in oscillator operating at an oscillation frequency of 50 kHz and a phase shift of 180 degrees and an electrical output of 120 W, and add approximately 2 ml of the Contaminon N to this water tank. (4) Set the beaker in (2) in the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height position of the beaker so that the resonance state of the liquid surface of the electrolytic aqueous solution in the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker in (4) with ultrasonic waves, add approximately 10 mg of toner (particles) little by little to the electrolytic aqueous solution and disperse it. Then, continue the ultrasonic dispersion treatment for another 60 seconds. In ultrasonic dispersion, appropriately adjust the water temperature in the water tank to be 10°C or higher and 40°C or lower. (6) Drop the electrolytic aqueous solution in (5) in which the toner (particles) is dispersed into the round-bottom beaker in (1) installed in the sample stand using a pipette, and adjust so that the measured concentration is approximately 5%. Then, perform the measurement until the measured number of particles reaches 50,000. (7) Analyze the measurement data using the dedicated software attached to the device to calculate the weight average particle size (D4). When setting to graph / volume% in the dedicated software, the analysis / volume statistical value (calculation The "average diameter" on the "arithmetic mean" screen is the weight average particle diameter (D4), and the "average diameter" on the "analysis / number statistical value (arithmetic mean)" screen is the number average particle diameter (D1) when set to graph / number% using dedicated software.

[0082] <Composition analysis of binder resin> · Separation method of binder resin Dissolve 100 mg of toner in 3 ml of chloroform. Then, remove the insoluble matter by suction filtration with a syringe equipped with a sample treatment filter (pore size 0.2 μm or more and 0.5 μm or less, for example, using Micron Disc H-25-2 (manufactured by Tosoh Corporation)). Introduce the soluble matter into preparative HPLC (apparatus: LC-9130 NEXT preparative column [60 cm] manufactured by Japan Analytical Industry Co., Ltd., exclusion limit: 20000, two connected with 70000) and send the chloroform eluent. When a peak can be confirmed in the obtained chromatogram display, collect the retention time with a molecular weight of 2000 or more using a monodisperse polystyrene standard sample. Dry and solidify the obtained solution of the fraction to obtain the binder resin.

[0083] · Identification of components of binder resin and measurement of weight ratio by nuclear magnetic resonance spectroscopy (NMR) Add 1 mL of deuterated chloroform to 20 mg of toner and measure the proton NMR spectrum of the dissolved binder resin. From the obtained NMR spectrum, the molar ratio and mass ratio of each monomer can be calculated, and the content of the constituent monomer units of the binder resin such as the amorphous polyester resin can be determined. For example, in the case of a styrene-acrylic copolymer, the composition ratio and mass ratio can be calculated based on the peak around 6.5 ppm derived from the styrene monomer and the peak around 3.5 - 4.0 ppm derived from the acrylic monomer. Also, in the case of a copolymer of polyester resin and styrene-acrylic resin, the molar ratio and weight ratio are calculated together from the peaks derived from each monomer constituting the polyester resin and the peaks derived from the styrene-acrylic copolymer, and the content of the monomer units of the polyester resin is determined. NMR apparatus: JEOL RESONANCE ECX500 Observed nucleus: Proton Measurement mode: Single pulse Reference peak: TMS

[0084] <Measurement of σr and Si Content of Magnetic Iron Oxide Particles B The measurement of σr and Si content of magnetic iron oxide particles B is carried out as follows. The external additive of the toner is removed by the method described above to obtain toner particles. The toner particles are dissolved in chloroform, and magnetic iron oxide particles B are recovered using a magnet. The obtained iron oxide particles B are immersed in chloroform, and the operation of recovering with a magnet is repeated three times to wash the magnetic iron oxide particles B. For the obtained magnetic iron oxide particles B, a vibrating magnetometer VSMP-1-10 (manufactured by Toei Industry Co., Ltd.) is used to measure the σr of the magnetic iron oxide particles B at an external magnetic field of 795.8 kA / m at a room temperature of 25°C. Further, 200 mg of the obtained magnetic iron oxide particles B are put into a cup for liquid sample measurement of fluorescent X-ray measurement and spread uniformly over the entire bottom surface. Using a fluorescent X-ray analyzer Axios (manufactured by PANalytical) and the attached dedicated software "SuperQ ver.4.0F" (manufactured by PANalytical), the Si content in the iron oxide is quantified by the fundamental parameter method under a He environment.

[0085] <Measurement of Weight-Average Molecular Weight Mw and Number-Average Molecular Weight Mn of Binder Resin The molecular weight distribution (weight-average molecular weight Mw, number-average molecular weight Mn) of the binder resin is measured by gel permeation chromatography (GPC) as follows. First, at room temperature over 24 hours, the sample is dissolved in tetrahydrofuran (THF). Then, the obtained solution is filtered through a solvent-resistant membrane filter "Micron Disc" (manufactured by Tosoh Corporation) with a pore size of 0.2 μm to obtain a sample solution. Note that the sample solution is adjusted so that the concentration of the components soluble in THF is 0.8% by mass. Using this sample solution, the measurement is carried out under the following conditions. Apparatus: HLC8120GPC (Detector: RI) (manufactured by Tosoh Corporation) · Column: 7-connected Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK) Eluent: Tetrahydrofuran (THF) · Flow rate: 1.0 ml / min ·Oven temperature: 40.0 °C ·Sample injection volume: 0.10 ml When calculating the molecular weight of the sample, a molecular weight calibration curve prepared using a standard polystyrene resin (for example, trade 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”, manufactured by Tosoh Corporation) is used.

Example

[0086] Hereinafter, the present invention will be described in more detail by production examples and examples, but these do not limit the present invention in any way. Note that all parts in the following formulations indicate parts by mass.

[0087] <Production Example of Non-Magnetic Inorganic Oxide Particles A1> A mixed gas with a volume ratio of argon to oxygen of 3:1 was introduced into the reaction vessel and replaced with air. Into this reaction vessel, oxygen gas was supplied at 40 (m 3 / hr) and hydrogen gas was supplied at 20 (m 3 / hr), and a combustion flame composed of oxygen-hydrogen was formed using an ignition device. Next, metal silicon powder as a raw material was introduced into this combustion flame with a hydrogen carrier gas at a pressure of 147 kPa (1.5 kg / cm 2 ) to form a dust cloud. This dust cloud was ignited by the combustion flame to cause an oxidation reaction by dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled to obtain silica powder with a number average particle diameter of 2.67 μm. This silica powder was pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation) to obtain non-magnetic inorganic oxide particles A1 with a number average particle diameter of 1520 nm.

[0088] <Production Examples of Non-Magnetic Inorganic Oxide Particles A4, A5, A11> In the production example of silica particles 1, while adjusting the pulverization intensity of the pulverizer, pulverization was performed to obtain non-magnetic inorganic oxide particles A4, A5, A11.

[0089] <Production Examples of Non-Magnetic Inorganic Oxide Particles A2, A3, A6, and A12> A mixed gas with a volume ratio of argon to oxygen of 3:1 was introduced into the reaction vessel and replaced with air. 40 m 3 / hr of oxygen gas and 20 m 3 / hr of hydrogen gas were supplied to the reaction vessel, and a combustion flame composed of oxygen and hydrogen was formed using an ignition device. Next, metallic silicon powder as a raw material was introduced into this combustion flame with a hydrogen carrier gas at a pressure of 0.5 kg / cm 3 to form a dust cloud. This dust cloud was ignited by the combustion flame to cause an oxidation reaction due to a dust explosion. After the oxidation reaction, the inside of the reaction vessel was cooled to obtain silica powder with a number average particle diameter of 3.44 μm. This silica powder was pulverized while adjusting the pulverization strength with a parabolizer to obtain non-magnetic inorganic oxide particles A2, A3, and A6. Also, those that were not pulverized by the parabolizer were designated as non-magnetic inorganic oxide particles A12.

[0090] <Production Example of Non-Magnetic Inorganic Oxide Particle A7> Ilmenite ore was dried, pulverized, and digested / extracted by treatment with concentrated sulfuric acid. After removing unreacted ore, iron sulfate was desolvated. An aqueous sodium hydroxide solution was added to the obtained titanyl sulfate to adjust the pH to 9.0, and desulfurization treatment was performed. Then, it was neutralized with hydrochloric acid to pH 5.8, followed by filtration and washing with water. After firing in a heating furnace, it was pulverized while adjusting the pulverization strength of the parabolizer to obtain titanium oxide, which is non-magnetic inorganic oxide particle A7.

[0091] <Production Example of Non-Magnetic Inorganic Oxide Particle A8> Magnesium oxide powder (Pyroquesima 3320 manufactured by Kyowa Chemical Industry Co., Ltd.) was pulverized while adjusting the pulverization strength using a parabolizer to obtain magnesium oxide particles, which are non-magnetic inorganic oxide particles A8.

[0092] <Production Example of Non-Magnetic Inorganic Oxide Particle A9> Using bauxite as a raw material, aluminum oxide was purified by the Bayer process. Sodium hydroxide was added to the bauxite and heated to dissolve at 250 °C. The insoluble matter was removed by filtration, and then aluminum hydroxide was recovered as a solid by cooling. This aluminum hydroxide was heated and dehydrated at 1050 °C to obtain aluminum oxide. Subsequently, while adjusting the grinding strength of the pulverizer, it was ground to obtain aluminum oxide particles which are non-magnetic inorganic oxide particles A9.

[0093] <Production Example of Non-Magnetic Inorganic Oxide Particles A10> Ilmenite ore was dried and pulverized, and then digested / extracted by treatment with concentrated sulfuric acid. After removing the unreacted ore, iron sulfate was decrystallized. An aqueous sodium hydroxide solution was added to the obtained titanyl sulfate to adjust the pH to 9.0, and desulfurization treatment was carried out. Then, it was neutralized with hydrochloric acid to pH 5.8, and filtered and washed with water. Water was added to the washed cake to make a 1.5 mol / L slurry as TiO2, and then hydrochloric acid was added to adjust the pH to 1.5 for peptization treatment. The metatitanic acid subjected to desulfurization and peptization was collected as TiO2 and put into a 3 L reaction vessel. An aqueous strontium chloride solution was added to the peptized metatitanic acid slurry so that the SrO / TiO2 molar ratio was 1.18, and then the TiO2 concentration was adjusted to 0.9 mol / L. Next, while stirring and mixing, it was heated to 90 °C, and then 444 mL of a 10 mol / L aqueous sodium hydroxide solution was added dropwise over 50 minutes while performing microbubbling of nitrogen gas at 600 ml / min. Then, stirring was carried out at 95 °C for 1 hour while performing microbubbling of nitrogen gas at 400 ml / min. Thereafter, the reaction slurry was stirred while flowing 10 °C cooling water through the jacket of the reaction vessel and rapidly cooled to 12 °C. Hydrochloric acid was added for neutralization and stirring was carried out for 1 hour, and then filtration and separation were performed. After firing in a heating furnace, it was ground while adjusting the grinding strength of the pulverizer to obtain strontium titanate which is non-magnetic inorganic oxide particles A10.

[0094]

Table 1

[0095] <Production Example of Magnetic Iron Oxide Particles B1> Into an aqueous solution of ferrous sulfate, a caustic soda solution in an amount of 1.00 to 1.10 equivalents relative to the iron element, P2O5 in an amount of 0.15% by mass in terms of phosphorus element relative to the iron element, and SiO2 in an amount of 1.50% by mass in terms of silicon element relative to the iron element were mixed to prepare an aqueous solution containing ferrous hydroxide. This was done. The pH of the aqueous solution was adjusted to 8.0, and an oxidation reaction was carried out at 85 °C while blowing air to prepare a slurry liquid having seed crystals.

[0096] Next, an aqueous solution of ferrous sulfate was added to this slurry liquid so as to be 0.90 to 1.20 equivalents relative to the initial alkali amount (sodium component of caustic soda). Then, the slurry liquid was maintained at pH 7.6, and the oxidation reaction was continued while blowing air to obtain a slurry liquid containing iron oxide. The produced magnetic iron oxide particles were filtered with a filter press, washed with a large amount of water, dried at 120 °C for 2 hours, and the obtained particles were crushed to obtain magnetic iron oxide particles B1 having a volume average particle diameter of 150 nm. The magnetic iron oxide particles B1 were spherical in shape.

[0097] <Production Examples of Magnetic Iron Oxide Particles B2 to B6> In the production example of magnetic iron oxide particles B1, the amount of SiO2 to be mixed was 0.3% by mass, and magnetic iron oxide particles B2 to B6 shown in Table 2 were obtained by adjusting the oxidation reaction at 85 °C and the holding time at pH 7.6.

Table 2

[0098] <Binder Resin> In the examples described later, the materials used as the binder resin are shown in Table 3.

Table 3

[0099] <Production Example of Toner 1> · Binder resin A-1: 100.0 parts ([Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane:Polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane:Terephthalic acid:Trimellitic acid = 80:20:85:15]) · Paraffin wax (HNP9: manufactured by Nippon Seiro Co., Ltd.): 6.0 parts · Non-magnetic inorganic oxide particles A1: 2.0 parts · Iron complex of monoazo dye (T-77 manufactured by Hodogaya Chemical Co., Ltd.): 2.0 parts · Magnetic iron oxide particles B1: 100 parts · Crystalline polyester resin A: 5 parts (1:1 condensate of sebacic acid and dodecanediol) Using a Henschel mixer (FM-75 type, manufactured by Mitsui Mining Co., Ltd.), the above materials were mixed at a rotation speed of 20 s -1 and a rotation time of 5 minutes, and then kneaded with a twin-screw kneader (PCM-30 type, manufactured by Ikegai Corporation) set at a temperature of 130°C. The obtained kneaded product was cooled to 25°C and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized product. The obtained coarsely pulverized product was finely pulverized with a mechanical pulverizer (T-250, manufactured by Turbo Industry Co., Ltd.). Classification was performed using a multi-division classifier utilizing the Coandă effect to obtain toner particles 1 having a weight average particle diameter (D4) of 7.5 μm.

[0100] To 100 parts of the obtained toner particles, 1.5 parts of hydrophobized silica fine powder having a number average particle diameter of primary particles of 10 nm was mixed for 5 minutes under the condition of a rotation speed of 3000 rpm with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) to obtain a toner mixture. Thereafter, coarse particles were removed using a 300-mesh sieve (aperture 48 μm) to obtain Toner 1. The weight average particle diameter of Toner 1 was 7.5 μm. The formulation of Toner 1 is shown in Table 4.

[0101]

Table 4

[0102] <Production Example of Toner 2> In the production example of Toner 1, except that magnetic iron oxide particles B1 were changed to magnetic iron oxide particles B2 and the types and amounts of the materials described in Table 4 were changed, Toner 2 was obtained in the same manner as the production of Toner 1.

[0103] <Production Example of Toner 3> In the production example of Toner 1, no crystalline polyester resin A was added, behenyl stearate was used as the wax, and except that the types and amounts of the materials described in Table 4 were changed, Toner 3 was obtained in the same manner as the production of Toner 1.

[0104] <Production Example of Toner 4> In the production example of Toner 3, except that binder resin A-1 was changed to binder resin A-2 having the following composition and the types and amounts of the materials described in Table 4 were changed, Toner 4 was obtained in the same manner as the production of Toner 3. Binder resin A-2: Styrene acrylic resin - polyester resin hybrid resin (mass ratio: styrene acrylic resin / polyester resin = 60 / 40) (mass ratio [polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: terephthalic acid: trimellitic acid: acrylic acid = 90:10:92:3:10, styrene: butyl acrylate = 90:40])

[0105] <Production Examples of Toners 5 to 18> In the production example of Toner 3, except that the binder resin A-2 was changed to the binder resin A-3 with the following composition and the types and amounts of the materials described in Table 4 were changed, Toners 5 to 18 were obtained in the same manner as the production of Toner 4. Note that the weight average particle diameter was appropriately controlled to the values in Table 5 by adjusting the intensity of fine grinding and the classification conditions. Binder resin A-3: Styrene acrylic resin (Mass ratio Styrene:n-butyl acrylate = 78:22)

[0106] <Comparative Example> <Production Examples of Toners 19 to 25> In the production example of Toner 1, except that the types and amounts of the materials described in Table 4 were changed, Toners 19 to 25 were obtained in the same manner as the production of Toner 1.

[0107] The physical properties of the obtained toners are shown in Table 5.

Table 5

[0108] In the table, the particle diameter is the weight average particle diameter (D4). The "ratio of A / B average diameters" is the value of the ratio of the number average particle diameter of the major axis of the non-magnetic inorganic oxide particles A to the number average particle diameter of the major axis of the magnetic iron oxide particles B. The "B / A number ratio" is the value of the ratio of the number of magnetic iron oxide particles B to the number of non-magnetic inorganic oxide particles A contained in the cross section of the toner particles. The "ratio of toner / A average diameters" is the value of the ratio of the weight average particle diameter of the toner to the number average particle diameter of the major axis of the non-magnetic inorganic oxide particles A. A number % is the "proportion of particles having a major axis of 400 nm or more and 3000 nm or less among the non-magnetic inorganic oxide particles A having a major axis of 100 nm or more", and B number % is the "proportion of particles having a major axis of 50 nm or more and 350 nm or less among the magnetic iron oxide particles B".

[0109] <Evaluation of Rubbing Fixing Property> Regarding the HP LaserJet Enterprise M609dn, in consideration of the fixing property evaluation at high speed, the process speed was modified to 500 mm / sec, the fixing temperature adjustment was lowered by 25°C from the setting, and the rubbing fixing property was evaluated. The evaluation of rubbing and fixing property was carried out by outputting a solid black image in a normal temperature and normal humidity environment, and evaluating it according to the degree of soiling of the silver paper (manufactured by Nikon) before and after rubbing. The paper used was OCE RED LABEL (basis weight: 80 g / m 2 ). For the fixed image, after rubbing back and forth 10 times with a load of 100 g / cm 2 using silver paper (manufactured by Nikon), it was evaluated according to the density of the soiling of the silver paper. The soiling was evaluated by the numerical value of the density difference between before use and the soiled part using a Macbeth reflection densitometer (manufactured by Macbeth), and A to C were judged as good. The evaluation results are shown in Table 6. In addition, Examples 14 to 18 were evaluated as reference examples. A: Density difference is 0 to 0.02 B: Density difference is 0.03 to 0.05 C: Density difference is 0.06 to 0.09 D: Density difference is 0.10 or more

[0110] <Evaluation of plain paper gloss> Considering the printing evaluation on a high-speed machine, the HP LaserJet Enterprise M609dn was modified to a process speed of 500 mm / sec, and the fixing temperature control was lowered by 25°C from the setting to evaluate the gloss. The paper used was OCE RED LABEL (basis weight: 80 g / m 2 ), and an image with 9 squares arranged in 3 rows and 3 columns with a side length of 20 mm (toner loading amount: 0.6 mg / cm 2 ) was printed. The gloss of this image was measured using a handy gloss meter PG-3D (manufactured by Tokyo Denshoku Industries Co., Ltd.) under the condition of a light incident angle of 75°, and the average gloss value of the 9 squares was obtained. The higher the gloss value, the smoother and glossier the image surface becomes, and the lower the gloss value, the more matte and calm the image impression becomes. A: Gloss less than 15 B: Gloss 15 or more and less than 25 C: Gloss 25 or more and less than 35 D: Gloss 35 or more and less than 40 E: Gloss 40 or more

[0111] <Evaluation of glossy paper gloss> When using glossy paper with a smooth surface, the fixing gloss is likely to increase, and the quality of black images is likely to deteriorate, so particularly strict evaluation can be carried out. Regarding the HP LaserJet Enterprise M609dn, considering the printing evaluation on a high-speed machine, the process speed was modified to 500 mm / sec, the fixing temperature control was lowered by 50 °C from the setting, and the gloss evaluation was performed. The paper used was glossy paper Image Coat Gloss 100 (basis weight: 100 g / m 2 (Canon Marketing Japan Inc.). An image with 9 squares arranged in 3 rows and 3 columns, each square having a side length of 20 mm (toner loading amount: 0.6 mg / cm 2 ) was printed. The gloss of this image was measured using a handy gloss meter PG-3D (manufactured by Tokyo Denshoku Industries Co., Ltd.) under the condition of a light incident angle of 75°, and the average gloss value of the 9 squares was obtained. A: Gloss less than 20 B: Gloss 20 or more and less than 30 C: Gloss 30 or more and less than 40 D: Gloss 40 or more and less than 50 E: Gloss 50 or more

[0112]

Table 6

Claims

1. A toner having toner particles containing a binder resin, non-magnetic inorganic oxide particles A, and magnetic iron oxide particles B, wherein the softening point of the chloroform-soluble component of the toner particles is 90°C or lower, the non-magnetic inorganic oxide particles A and the magnetic iron oxide particles B are incorporated into the toner particles, the non-magnetic inorganic oxide particles A are silica particles, the content of the non-magnetic inorganic oxide particles A is 0.1 part by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the binder resin, the content of the magnetic iron oxide particles B is 50 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the binder resin, the number average value of the major axis diameters of the non-magnetic inorganic oxide particles A is 400 nm or more and 3000 nm or less, the number average value of the major axis diameters of the magnetic iron oxide particles B is 50 nm or more and 350 nm or less, among the non-magnetic inorganic oxide particles A having a major axis diameter of 100 nm or more, the proportion of particles having a major axis diameter of 400 nm or more and 3000 nm or less is 70% by number or more, among the magnetic iron oxide particles B, the proportion of particles having a major axis diameter of 50 nm or more and 350 nm or less is 70% by number or more, a toner characterized in that the value of the ratio of the number average value of the major axis diameter of the non-magnetic inorganic oxide particles A to the number average value of the major axis diameter of the magnetic iron oxide particles B is 5 or more and 30 or less.

2. In the observation by a transmission electron microscope of a cross section of the toner particles cut with a microtome, 0.5 to 5.0 non-magnetic inorganic oxide particles A are present per cross section of the toner particles, the toner according to claim 1, wherein the value of the ratio of the number of magnetic iron oxide particles B to the number of non-magnetic inorganic oxide particles A contained in the cross section of the toner particles (magnetic iron oxide particles B / non-magnetic inorganic oxide particles A) is 50 to 500.

3. In the observation by a transmission electron microscope of a cross section of the toner particles cut with a microtome, the shape factor SF1 of the non-magnetic inorganic oxide particles A is 140 or more, the toner according to claim 1 or 2, wherein the shape factor SF1 of the magnetic iron oxide particles B is 110 or less.

4. The toner according to any one of claims 1 to 3, wherein among the non-magnetic inorganic oxide particles A having a major axis diameter of 100 nm or more, the proportion of particles having a major axis diameter of 800 nm or more and 3000 nm or less is 70% by number or more.

5. The toner according to any one of claims 1 to 4, wherein the value of the ratio of the weight average particle diameter of the toner to the number average value of the major axis diameter of the non-magnetic inorganic oxide particles A is 2 or more and 15 or less.

6. The toner according to any one of claims 1 to 5, wherein the binder resin contains an amorphous polyester resin.

7. The toner according to claim 6, wherein the content ratio of the amorphous polyester resin in the binder resin is 50% by mass or more.

8. The toner according to any one of claims 1 to 7, wherein the number average molecular weight (Mn) of the binder resin is from 1,000 to 5,000.

9. The residual magnetization (σr) of the magnetic iron oxide particles B is 4 Am ２ / kg to 18 Am ２ / kg, and the toner according to any one of claims 1 to 8

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