TONER

Abstract

Toner that includes: a toner particle; inorganic fine particles A; and inorganic fine particles B, wherein a weight-averaged particle diameter D4 of the toner is at least 3.0 µm and not more than 10.0 µm; the inorganic fine particles A and the inorganic fine particles B are strontium titanate; a number-average particle diameter of primary particles of the inorganic fine particles A is at least 10 nm and not more than 95 nm; the inorganic fine particles A exhibit a maximum peak (a) at a diffraction angle 2θ of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction; a half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°; the inorganic fine particles A exhibit a water adsorption quantity of at least 1 mg / g and not more than 40 mg / g at a relative humidity of 80% in a water adsorption isotherm at 30°C; and a number-mean particle diameter of primary particles of the inorganic fine particles B is at least 500 nm and not more than 2000 nm.

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a toner used in an image generation method and a toner jet system for visualizing an electrophotograph and an electrostatic image. Description of the related prior art

[0002] Since image-generating devices, such as copiers and printers, have become widespread in recent years, higher image quality is expected as a performance characteristic for image-generating devices, in addition to higher speed and a longer lifespan.

[0003] Reducing the toner particle diameter has proven to be a means of achieving high image quality in imaging devices. While a smaller toner particle diameter improves dot and fine line reproduction, it also increases the likelihood of uneven toner flow and loading performance.

[0004] Particularly when a large number of images with the same pattern are printed, the loading capacity and flow of the toner on the developer cartridge (or developer drum) tend to be uneven between printed and unprinted sections. In some cases where different images are printed continuously while the toner loading capacity and flow remain uneven, the history of the previous image may be reflected as a difference in print density (hereinafter referred to as "cartridge ghosting").

[0005] For example, Japanese patent application publication number JP 2016-110095 A discloses a technique capable of controlling toner performance and flowability and suppressing a cartridge ghost image under a low temperature and low humidity environment by adding silicon oxide with a number-average particle diameter of at least 5 nm and not more than 20 nm and silicon oxide with a number-average particle diameter of at least 80 nm and not more than 200 nm to a toner.

[0006] Another problem is that if the toner loading distribution on the developer cartridge is wide, especially if the toner is used for a long time in a high-temperature and high-humidity environment, the toner with a low loading amount accumulates in the developer device, fine line and dot reproducibility deteriorates, and the quality of a fine image may be worsened.

[0007] When the toner particle diameter becomes small, it is unlikely that the toner will be scraped off by the cleaning blade during the cleaning step, and the toner will easily pass through the cleaning blade. In other words, so-called cleaning defects are likely to occur.

[0008] A method of adding strontium titanate to a toner particle is known as a remedy against cleaning defects. For example, Japanese patent application publication number JP 2006-195156 A discloses a technique for preventing cleaning defects by using a toner containing strontium titanate with a number-mean particle diameter of at least 80 nm and not more than 220 nm and strontium titanate with a number-mean diameter of at least 300 nm and not more than 3000 nm.

[0009] Furthermore, Japanese patent no. JP 4799567 B2 discloses a technique for preventing cleaning defects by using a toner containing composite inorganic fine powder that includes strontium titanate with a half-width of an X-ray peak at 32.20° of 0.20 to 0.30°.

[0010] Furthermore, Japanese patent no. JP 4979517 B2 discloses a technique for improving transferability by using a toner containing a composite oxide that includes strontium titanate with a half-width of an X-ray diffraction peak at 32.20° of 0.20 to 0.30°.

[0011] JP 5241098 B2 discloses an image-generating method using a developer with toner particles and inorganic fine powder. JP 2010-19881 A discloses a toner comprising toner particles, an inorganic fine powder A, and an inorganic fine powder B. JP 2010-151921 A discloses an image-generating apparatus that employs a developer comprising inorganic fine particles A and inorganic fine particles B, which are provided on the surfaces of magnetic toner particles. SUMMARY OF THE INVENTION

[0012] However, the invention described in Japanese patent application publication number JP 2016-110095 A requires a further improvement regarding a ghost image of a cartridge case under a high temperature and high humidity environment.

[0013] Similarly, the toner of Japanese patent application publication number JP 2006-195156 A exhibits a certain effect in suppressing cleaning defects. However, investigations by the inventors of the present invention revealed that when printing continuously at a high pressure percentage in a low-temperature and low-humidity environment using a toner containing strontium titanate with a particle diameter of at least 300 nm, aggregates of strontium titanate and toner are likely to form inside the developer apparatus. It was subsequently found that the high abrasiveness of strontium titanate causes so-called white streaks, which are abraded sections of the cartridge surface where no pressure is applied, and further improvement of this is essential.

[0014] Furthermore, a further improvement against a shell ghost image is required in the Japanese patents No. JP 4799567 B2 and No. JP 4979517 B2.

[0015] The present invention is designed to solve the above problems, and it is an object of the present invention to provide a toner in which it is unlikely to cause a spool ghost image, even when used in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, and which is excellent with respect to fine line reproducibility and dot reproducibility, even when used for a long time in a high-temperature and high-humidity environment.

[0016] It is a further object of the present invention to provide a toner that is able to suppress cleaning defects of a photosensitive element and also to suppress white streaks and cartridge ghost images, even when used in a high temperature and high humidity environment or a low temperature and low humidity environment.

[0017] According to a first aspect of the present invention, a toner is provided which is characterized in that it comprises a toner particle and strontium titanate, wherein a number-mean particle diameter of primary particles of strontium titanate is at least 10 nm and not more than 95 nm; the strontium titanate exhibits a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction; The half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°; an intensity (Ia) of the maximum peak (a) and a maximum peak intensity (Ix) in a region of a diffraction angle (2θ) of at least 24.00° and not more than 28.00° in CuKα characteristic X-ray diffraction satisfy the following formula (1): (Ix) / (Ia)≤0.010 The strontium titanate is such that, if all elements detected by X-ray fluorescence analysis of the strontium titanate are assumed to be present in the form of oxides, and if a total amount of all the oxides is assumed to be 100% by mass, the total content of strontium oxide and titanium oxide is at least 98.0% by mass; and a sum total Et of a rotational torque and a vertical load, which is obtained when, in the powder flowability analysis of the toner, a propeller-like blade is inserted vertically into a powder layer of the toner in a measuring vessel under rotation at a peripheral velocity of the outermost edge region thereof of 100 mm / second, the measurement is started at a position 100 mm from a bottom surface of the powder layer, and the propeller-like blade is inserted to a position of 10 mm from the bottom surface, is at least 100 mJ and not more than 2000 mJ.

[0018] According to a second aspect of the present invention, a toner is provided which is characterized in that it comprises a toner particle, inorganic fine particles A and inorganic fine particles B, wherein a weight-averaged particle diameter (D4) of the toner is at least 3.0 µm and not more than 10.0 µm; the inorganic fine particles A and the inorganic fine particles B are strontium titanate; a number-average particle diameter of primary particles of the inorganic fine particles A is at least 10 nm and not more than 95 nm; the inorganic fine particles A exhibit a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction; a half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°; the inorganic fine particles A exhibit a water adsorption quantity of at least 1 mg / g and not more than 40 mg / g at a relative humidity of 80% in a water adsorption isotherm at 30°C; and a number-mean particle diameter of primary particles of the inorganic fine particles B is at least 500 nm and not more than 2000 nm.

[0019] According to the first aspect of the present invention, it is possible to provide a toner which is unlikely to produce a spool ghost image, even when used in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, and which is excellent with respect to fine line reproducibility and dot reproducibility, even when used for a long time in a high-temperature and high-humidity environment.

[0020] According to the second aspect of the present invention, it is possible to provide a toner that is able to suppress cleaning defects of a photosensitive element and also suppress white streaks and spool ghost images, even when used in a high temperature and high humidity environment or a low temperature and low humidity environment.

[0021] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an example of a sample image for evaluating a shell ghost image; and Fig. 2 is an example of an image for evaluating a husk ghost image. DESCRIPTION OF THE EXECUTION FORMS

[0022] In the present invention, the expressions “at least OO and not more than XX” and “OO to XX”, which represent a numerical range, mean a numerical range that includes a lower limit and an upper limit, which are the endpoints, unless otherwise specified. First aspect

[0023] The first aspect of the present case will be described in detail below.

[0024] According to the first aspect, a toner is provided which is characterized by containing toner particles in strontium titanate, wherein a number-mean particle diameter of primary particles of strontium titanate is at least 10 nm and not more than 95 nm; the strontium titanate exhibits a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction; The half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°; an intensity (Ia) of the maximum peak (a) and a maximum peak intensity (Ix) in a region of a diffraction angle (2θ) of at least 24.00° and not more than 28.00° in CuKα characteristic X-ray diffraction satisfy the following formula (1): (Ix) / (Ia)≤0.010 The strontium titanate is such that, if all elements detected by X-ray fluorescence analysis of the strontium titanate are assumed to be present in the form of oxides, and if a total amount of all the oxides is assumed to be 100% by mass, the total content of strontium oxide and titanium oxide is at least 98.0% by mass; and a sum total Et of a rotational torque and a vertical load, which is obtained when, in the powder flowability analysis of the toner, a propeller-like blade is inserted vertically into a powder layer of the toner in a measuring vessel under rotation at a peripheral velocity of the outermost edge region thereof of 100 mm / second, the measurement is started at a position 100 mm from a bottom surface of the powder layer, and the propeller-like blade is inserted to a position of 10 mm from the bottom surface, is at least 100 mJ and not more than 2000 mJ.

[0025] The above toner is unlikely to produce a snare ghost image, even when used in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, and is excellent in terms of fine line and dot reproducibility, even when used for a long time in a high-temperature and high-humidity environment.

[0026] The reason why the above characteristics make it possible to achieve excellent effects that could not be obtained before is assumed to be as described below.

[0027] In the present invention, the strontium titanate is characterized in that it has a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction, and a half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°. The maximum peak (a) corresponds to the (1,1,0)-plane peak of a strontium titanate crystal.

[0028] As a result of intensive investigations, the inventors of the present invention found that it is very important to set the full width at least 0.23° and no more than 0.50°.

[0029] In general, the half-width of the diffraction peak in X-ray diffraction is related to the crystallite size of strontium titanate. A primary particle is composed of a plurality of crystallites, and the crystallite size is the size of each crystallite that makes up the primary particle.

[0030] In the present invention, the term "crystallite" refers to individual crystal grains that constitute a particle, and the crystallites combine to form a particle. Crystallite size and particle size are not related. If the crystallite size of strontium titanate is small, the full width at half maximum (FWHM) is large, and if the crystallite size of strontium titanate is large, the FWHM is reduced.

[0031] The half-width of the diffraction peak in X-ray diffraction of the strontium titanate of the present invention is at least 0.23° and not more than 0.50°, which means that the crystallite size is smaller than that of conventional strontium titanate.

[0032] As the crystallite size of strontium titanate decreases, grain boundaries (crystal grain boundaries) of crystallites present in primary particles increase. The crystal grain boundary is considered a location where electrical charges are trapped.

[0033] Therefore, if the toner's charge is low, the increase in its triboelectric charge is accelerated because grain boundaries are highly likely to trap electrical charges. However, since the interior of the strontium titanate crystallites allows the toner's electrical charge to dissipate easily, it can be assumed that if the toner becomes excessively charged, exceeding the charge that can be trapped by the crystal grain boundaries, electrical charges will pass through the interior of the crystallite, thus suppressing excessive toner charging.

[0034] Thus, by controlling the half-value width to at least 0.23° and no more than 0.50°, it is possible to achieve the effect of accelerating the toner charge rise and suppressing excessive toner loading, which cannot be obtained with conventional strontium titanate. As a result, it is possible to maintain uniform toner loading performance in both the printed and unprinted areas of the cartridge case, even when printing a large number of images of the same pattern. Therefore, it can be assumed that the suppression of cartridge ghosting is drastically improved, even when the toner is used in high-temperature and high-humidity or low-temperature and low-humidity environments.

[0035] Improving the effect of accelerating the toner charge increase on the developer cartridge and suppressing excessive charging also results in a sharper toner charge distribution. If the toner charge distribution is wide, especially when the toner is used for a long time in a high-temperature and high-humidity environment, toner with a low charge accumulates in the developer unit, deteriorating fine line and dot reproduction, and potentially compromising the image quality of fine details.

[0036] Since the effect of accelerating the charge increase of the toner and suppressing excessive charging is satisfactory in the present invention, it becomes possible to provide a toner which has a sharp charge distribution of the toner and exhibits satisfactory fine line reproducibility and dot reproducibility, even when used for a long time in a high temperature and high humidity environment.

[0037] In the present invention, it is important that the half-width of the diffraction peak in X-ray diffraction of strontium titanate is at least 0.23° and not more than 0.50°, more preferably 0.25° and not more than 0.45°, and further preferably at least 0.28° and not more than 0.40°. Within the above ranges, the ghosting of cartridges is better prevented, even when the toner is used in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, and the fine line and dot reproducibility of the toner are satisfactory, even when the toner is used for a long time in a high-temperature and high-humidity environment.

[0038] In the present invention, it is important that the intensity (Ia) of the maximum peak (a) and the maximum peak intensity (Ix) in a region of a diffraction angle (2θ) of at least 24.00° and not more than 28.00° in CuKα characteristic X-ray diffraction satisfy the following formula (1): (Ix) / (Ia)≤0.010

[0039] Here, (Ix) represents the peaks of SrCO3 and TiO2 derived from the raw material of strontium titanate.

[0040] If (Ix) / (Ia) does not satisfy formula (1), this means that the purity of the strontium titanate is low. For example, if SrCO3 and TiO2, derived from the raw material of strontium titanate, remain as impurities, their maximum peak intensity (Ix) will be large, and formula (1) will not be satisfied. In this case, the impurities tend to localize at the crystal grain boundaries, and electrical charges are not trapped at the crystal grain boundaries and are likely to escape. Therefore, the charge rise is slowed.

[0041] If, meanwhile, formula (1) is satisfied, since the purity of strontium titanate is high and only a few impurities are localized at the crystal grain boundaries, it is likely that electrical charges will be trapped at the crystal grain boundaries, and the charge build-up will be accelerated. As a result, snare ghosting is unlikely to occur, even when the toner is used in a high-temperature and high-humidity environment, and fine line and dot reproducibility are improved, even when the toner is used for a long time in a high-temperature and high-humidity environment.

[0042] It is important that formula (1) (Ix) / (Ia) ≤ 0.010, and preferably (Ix) / (Ia) ≤ 0.008. It is preferred that there is no impurity-derived peak (Ix).

[0043] The ratio (Ix) / (Ia) can be controlled by the mixing ratio of a titanium raw material and a strontium raw material, a reaction temperature, and a reaction time. Furthermore, the ratio can be controlled by acid washing the strontium titanate slurry after the reaction.

[0044] In the present invention, it is important that the strontium titanate is such that, if all elements detected by X-ray fluorescence analysis of the strontium titanate are assumed to be present in the form of oxides, and if the total amount of all oxides is assumed to be 100% by mass, the total content of strontium oxide and titanium oxide is at least 98.0% by mass.

[0045] If the aforementioned content is less than 98.0 wt%, this indicates that a large number of impurities, other than strontium titanate, are present within the crystal. When a large number of impurities are present within the strontium titanate crystal, they disrupt the crystal structure, increasing the full width at half maximum (FWHM). In this case, although it is possible to increase the FWHM, it is difficult to control the crystallite size to a small size, resulting in reduced crystal grain boundaries and a tendency for electrical charges to escape. Consequently, the charge propagation is slowed.By adjusting the strontium oxide and titanium oxide content to at least 98.0 wt%, the crystallite size of the strontium titanate particles can be controlled to a small size, thus improving the effect of accelerating charge rise and suppressing excessive loading. As a result, case ghosting is unlikely to occur, even when the toner is used in a high-temperature and high-humidity environment, and fine line and dot reproducibility are improved, even after prolonged use in such environments.

[0046] The strontium oxide and titanium oxide content is preferably at least 98.2% by weight. Although the upper limit is not specifically defined, it is preferably not more than 100% by weight. This content can be controlled by refining the titanium raw material and reducing the amount of impurities.

[0047] The number-average particle diameter of the primary strontium titanate particles in the present invention is characterized in that it is at least 10 nm and not more than 95 nm. If the number-average particle diameter of the primary particles is at least 10 nm, the strontium titanate is effectively finely dispersed on the surface of the toner particles to suppress excessive toner loading. If the number-average particle diameter of the primary particles is not more than 95 nm, it is possible to obtain sufficient adhesion of strontium titanate to the toner particle, accelerate the increase in toner loading, and effectively suppress excessive toner loading.Therefore, it is possible to provide a toner that is better prevented from causing spool ghosting, even when used in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, and that exhibits satisfactory fine line and dot reproducibility, even when used for a long time in a high-temperature and high-humidity environment.

[0048] The number-mean particle diameter of the primary strontium titanate particles is preferably at least 10 nm and not more than 70 nm, and more preferably at least 10 nm and not more than 50 nm. The number-mean particle diameter of the primary strontium titanate particles can be controlled by the concentration of the titanium and strontium raw materials, the reaction temperature, and the reaction time.

[0049] The toner of the present invention is characterized in that the sum total Et of a rotational torque and a vertical load (or vertical stress), which is obtained when, in a powder flowability analysis, a propeller-like blade is inserted vertically into a powder layer of the toner in a measuring container, while it is rotated with a peripheral speed of the outermost edge section thereof of 100 mm / second, the measurement is started from a position 100 mm from a bottom surface of the powder layer, and the propeller-like blade is inserted to a position of 10 mm from the bottom surface, is at least 100 mJ and not more than 2000 mJ.

[0050] The measurement condition of Et shows the flow state of the toner near the developer sleeve, against which the toner is rubbed at high speed in the developer device. In particular, the measurement condition indicates a flow state immediately before the toner, which is carried on the surface of the developer sleeve, enters the opposite section between the developer layer regulating element and the developer sleeve.

[0051] By controlling the Et value to at least 100 mJ and no more than 2000 mJ, the force applied to the toner by the developer layer regulating element can be controlled to a constant value, thus ensuring a uniform toner layer thickness on the developer tube. Therefore, even when printing a large number of images of the same pattern, it is possible to maintain uniform toner loading and flow in both the printed and unprinted sections of the developer tube. As a result, tube ghosting is prevented, and fine line and dot reproduction are improved.

[0052] The Et value is preferably at least 200 mJ and not more than 1000 mJ, and more preferably at least 200 mJ and not more than 500 mJ.

[0053] To control the edentity, the temperature in the mixer's tank, when the toner particles and an external additive are mixed, is set to at least -20°C and no more than -10°C, the difference between the glass transition temperature (Tg) of the toner particle and the tank temperature [Tg - (temperature in the tank)]. This makes it easier to get the external additive to adhere to the surface of the toner particle, thus making the toner's edentity easier to control.

[0054] The strontium titanate content is preferably 0.05 parts by mass and not more than 2.0 parts by mass, and more preferably at least 0.1 parts by mass and not more than 1.5 parts by mass, based on 100 parts by mass of the toner particles.

[0055] Within the above range, it is easy to achieve the effect of suppressing excessive toner charging and accelerating the increase in triboelectric charge. Therefore, ghosting is unlikely to occur, whether the toner is used in a high-temperature and high-humidity or a low-temperature and low-humidity environment, and fine line and dot reproducibility are improved, even when the toner is used for extended periods in a high-temperature and high-humidity environment.

[0056] The strontium titanate of the present invention preferably has a moisture adsorption capacity of at least 1 mg / g and not more than 40 mg / g, more preferably at least 1 mg / g and not more than 25 mg / g, and even more preferably at least 1 mg / g and not more than 20 mg / g at a temperature of 30°C and a humidity of 80% RH.

[0057] By controlling the amount of moisture adsorption within the above ranges, it is possible to reduce the impact of decreasing the charge in a high-temperature and high-humidity environment, thus accelerating the charge build-up and ensuring a more uniform charge. As a result, ghosting is unlikely to occur, even when the toner is used in a high-temperature and high-humidity environment, and fine line and dot reproducibility are improved, even after prolonged use in such environments. Second aspect

[0058] According to the second aspect of the present invention, a toner is provided which is characterized in that it contains toner particles, inorganic fine particles A and inorganic fine particles B, wherein a weight-averaged particle diameter (D4) of the toner is at least 3.0 µm and not more than 10.0 µm; the inorganic fine particles A and the inorganic fine particles B are strontium titanate; a number-average particle diameter of primary particles of the inorganic fine particles A is at least 10 nm and not more than 95 nm; the inorganic fine particles A exhibit a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction; a half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°; the inorganic fine particles A exhibit a water adsorption quantity of at least 1 mg / g and not more than 40 mg / g at a relative humidity of 80% in a water adsorption isotherm at 30°C; and a number-mean particle diameter of primary particles of the inorganic fine particles B is at least 500 nm and not more than 2000 nm.

[0059] The toner according to the second aspect contains inorganic fine particles A and inorganic fine particles B. The inorganic fine particles A and the inorganic fine particles B are strontium titanate.

[0060] The number-average particle diameter of the primary inorganic fine particles A is at least 10 nm and no more than 95 nm. If the number-average particle diameter is at least 10 nm, the inorganic fine particles A are effectively finely dispersed on the surface of the toner particles, and excessive loading of the toner and the inorganic fine particles B is suppressed. Conversely, if the number-average particle diameter is no more than 95 nm, it is possible to obtain sufficient adhesion force to ensure that the inorganic fine particles A remain on the toner surface, thus maintaining the effect of accelerating the increase in the toner charge and suppressing excessive loading.Therefore, even when the toner is used in a high-temperature and high-humidity environment or a low-temperature and low-humidity environment, the appearance of cartridge ghosting and white streaks can be suppressed.

[0061] The number-average particle diameter of the primary particles of the inorganic fine particles A is preferably at least 10 nm and not more than 70 nm, and further preferably at least 10 nm and not more than 50 nm.

[0062] Furthermore, the inorganic fine particles A exhibit a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction, and a half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°, preferably at least 0.25° and not more than 0.45°, and more preferably at least 0.28° and not more than 0.40°. Such a feature is similar to that of strontium titanate according to the first aspect, and using the inorganic fine particles A, it is possible to achieve the effect of accelerating the charge increase of the toner on the developer cartridge and suppressing excessive loading.

[0063] Meanwhile, the number-average particle diameter of the primary particles of the inorganic fine particles B is at least 500 nm and no more than 2000 nm. With such inorganic fine particles B, it is possible to suppress purification defects.

[0064] The toner remaining on the photosensitive element after the transfer step is scraped off by cleaning devices, such as a cleaning blade, which is in contact with the photosensitive element. A cleaning defect occurs when toner or external additive partially passes through (or past) the cleaning blade. As a result, the toner or external additive that has passed through contaminates the load element, or the toner that has passed through forms a vertical streak and causes image defects.

[0065] The number-average particle diameter of the primary particles of the inorganic fine particles B is preferably at least 600 nm and not more than 1500 nm, and more preferably at least 600 nm and not more than 1000 nm.

[0066] When the toner containing inorganic fine particles B is used, it is likely that the inorganic fine particles B, which are scraped off by the cleaning blade, will accumulate at a contact point between the cleaning blade and the photosensitive element, so that a blocking layer can be formed by the inorganic fine particles B, which will result in the toner or an external additive being prevented from passing through.

[0067] However, it was found that when an image is printed continuously at a high ink density, aggregates of toner and inorganic fine particles B form in the developer unit and scratch the cartridge, causing white streaks. Furthermore, it was found that the suppression of cleaning defects resulting from the formation of the blocking layer, which is the function of the inorganic fine particles B, is also only minimally effective due to the aggregation of these particles. Therefore, the inventors of the present invention discovered, as a result of intensive investigations, that by simultaneously using inorganic fine particles A, it is possible to suppress the formation of aggregates of toner and inorganic fine particles B and to suppress white streaks, while simultaneously suppressing cleaning defects.

[0068] The following reason for the above effects can be assumed. It is known that the inorganic particles B, which are strontium titanate with a particle diameter of at least 500 nm and not more than 2000 nm, have a charge-imparting effect on the toner. In particular, when an image is printed continuously at a high pressure, it can be imagined that the charge increase of the toner is slowed down, and the charge-imparting effect of the inorganic particles B is increased. Since the inorganic particles B are charged with a polarity opposite to that of the toner, it is conceivable that a strong electrostatic adhesion force acts between the toner and the inorganic particles B, and that aggregates are formed, causing white streaks.Furthermore, if the inorganic fine particles B are present as agglomerates with the toner, it is conceivable that the formation of a blocking layer in the cleaning blade section is also hindered, leading to cleaning defects. Meanwhile, it is conceivable that the inorganic fine particles A make it possible to achieve the effect described above of suppressing excessive loading of the toner and the inorganic fine particles B. It is conceivable that the electrostatic adhesion force generated between the toner and the inorganic fine particles B decreases under the influence of the inorganic fine particles A, thereby suppressing the formation of the aggregates. It is reasonable to assume that this can result in the suppression of cleaning defects and white streaks.

[0069] In the second aspect, it is important that the weight-averaged particle diameter (D4) of the toner is at least 3.0 µm and no more than 10.0 µm. Within this range, the inorganic fine particles A can be effectively finely dispersed on the toner surface.

[0070] The weight-averaged particle diameter (D4) is preferably at least 4.0 µm and not more than 9.0 µm, more preferably at least 4.5 µm and not more than 8.5 µm and further preferably at least 5.0 µm and not more than 8.0 µm.

[0071] Furthermore, it is important that the inorganic fine particles A exhibit a water adsorption capacity of at least 1 mg / g and no more than 40 mg / g at a relative humidity of 80% in a water adsorption isotherm at 30°C. By controlling the moisture adsorption capacity within the above range, it is possible to reduce the influence of moisture on charge control, particularly in high-temperature and high-humidity environments, effectively maintain the excessive charge suppression effect, and suppress the appearance of case ghosting and white streaks.

[0072] The moisture adsorption rate is more preferably at least 1 mg / g and not more than 25 mg / g, and more preferably at least 1 mg / g and not more than 20 mg / g. As a result, ghosting is unlikely to occur, even when the toner is used in a high-temperature and high-humidity environment. The moisture adsorption rate can be controlled by surface-treating the inorganic fine particles A with a hydrophobic treatment agent.

[0073] The content of the inorganic fine particles A is preferably at least 0.05 parts by mass and not more than 2.0 parts by mass, and more preferably at least 0.1 parts by mass and not more than 1.5 parts by mass based on 100 parts by mass of the toner particles.

[0074] By adjusting the content of inorganic fine particles A to the above range, it is easy to achieve the effect of suppressing excessive toner loading and accelerating the charge rise, thus better preventing case ghosting and white streaks, even when the toner is used in high-temperature and high-humidity environments and low-temperature and low-humidity environments.

[0075] Furthermore, from the point of view of suppressing the occurrence of aggregates, the mass ratio [A / B] of the inorganic fine particles A and the inorganic fine particles B is preferably 1.0 / 1.0 to 1.0 / 20.0, and more preferably 1.0 / 3.0 to 1.0 / 18.0.

[0076] It is preferred that the inorganic fine particles A have a maximum peak (a) at a diffraction angle (2θ) of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction, and that an intensity (Ia) of the maximum peak (a) and a maximum peak intensity (Ix) in a region of a diffraction angle (2θ) of at least 24.00° and not more than 28.00° in CuKα characteristic X-ray diffraction satisfy the following formula: (Ix) / (Ia)≤0.010.

[0077] It is more strongly preferred that (Ix) / (Ia) is not more than 0.008.

[0078] This characteristic is similar to that of the first aspect. If the above formula is fulfilled, the number of impurities localized at the crystal grain boundaries is reduced, the toner charge increase is accelerated, the effect of suppressing excessive loading is easily achieved, and cleaning defects, case ghosting, and white streaks are unlikely to occur.

[0079] It is preferred that the inorganic fine particles A are such that, if all elements detected by X-ray fluorescence analysis of the inorganic fine particles A are assumed to be present in the form of oxides, and if a total amount of all oxides is assumed to be 100 wt%, the total content of strontium oxide and titanium oxide is at least 98.0 wt%, more preferably at least 98.2 wt%.

[0080] This characteristic is similar to the first aspect. If the above conditions are met, the charge build-up is likely to be accelerated and overloading suppressed. As a result, cleaning defects, case ghosting, and white streaks are unlikely to occur.

[0081] Next, preferred embodiments will be described in the first aspect and the second aspect.

[0082] The strontium titanate or the inorganic fine particles A are preferably surface-treated as required to control their hydrophobicity and triboelectric charging properties. Examples of such treatment agents include unmodified silicone lacquers, various modified silicone lacquers, unmodified silicone oils, various modified silicone oils, silane coupling agents, silane compounds with functional groups, and other organosilicon compounds. Various treatment agents can be used in combination. Of particular preference is the use of a silane coupling agent. Therefore, it is preferred that the strontium titanate or the inorganic fine particles A are surface-treated with a silane coupling agent.

[0083] Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-y-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, n-butyltrimethoxysilane, Isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-Octyltrimethoxysilane, n-Octyltriethoxysilane, n-Decyltrimethoxysilane, Hydroxypropyltrimethoxysilane, n-Hexadecyltrimethoxysilane, n-Octadecyltrimethoxysilane, Trifluoropropyltrimethoxysilane, and hydrolysates thereof.

[0084] Among these, n-octyltriethoxysilane, isobutyltrimethoxysilane, and trifluoropropyltrimethoxysilane are preferred, with isobutyltrimethoxysilane being more preferred. Furthermore, one of these treatment agents can be used individually, or two or more can be used in combination.

[0085] The surface of the strontium titanate particles can be chemically modified by surface treatment, but the surface treatment does not affect the crystal structure of the strontium titanate particles. Thus, the surface treatment does not affect the full width at half maximum (FWHM) of the maximum peak (a) of the strontium titanate. Therefore, in the present invention, X-ray fluorescence measurement of strontium titanate or inorganic fine particles A is carried out before surface treatment to measure the impurity elements that affect the crystal structure.

[0086] In the first aspect and the second aspect, the specific surface area of ​​the strontium titanate or the inorganic fine particles A, measured by a BET method using nitrogen adsorption, is preferably 10 m² after surface treatment. 2 / g and no more than 200 m 2 / g, and more preferably at least 10 m 2 / g and not more than 100 m 2 / g. As a result of controlling the BET-specific surface area within the above ranges, it is likely that the inorganic fine particles are uniformly and finely distributed on the toner surface, making it possible to exert a sufficient effect of suppressing excessive toner loading and accelerating charge increase.

[0087] The manufacturing process for strontium titanate or inorganic fine particles A is not particularly limited and, for example, the following process can be used.

[0088] For example, a synthesis can be carried out by adding strontium nitrate, strontium chloride, or the like to a titanium oxide sol dispersion obtained by adjusting the pH of an aqueous titanium oxide slurry, which is obtained by hydrolyzing an aqueous solution of titanyl sulfate, heating to a reaction temperature, and then adding an aqueous alkaline solution. The reaction temperature is preferably 60°C to 100°C.

[0089] It is preferred that the time taken to add the alkaline aqueous solution should not exceed 60 minutes in the addition step, in order to control the full width at half maximum (FWHM) of the maximum peak (a). By setting the addition rate of the alkaline aqueous solution to no more than 60 minutes, it is possible to obtain particles with a small crystallite size.

[0090] Furthermore, with regard to controlling the full width at half maximum (FWHM), it is preferable to carry out the addition while ultrasonic vibrations are applied (or while an ultrasonic treatment is being performed) during the addition of the alkaline aqueous solution. As a result of applying ultrasonic vibrations in the reaction step, the crystal deposition rate is increased and particles with a small crystallite size can be obtained.

[0091] Furthermore, with regard to controlling the full width at half maximum (FWHM), it is preferred to rapidly cool the aqueous solution after the reaction has ceased by adding an alkaline aqueous solution. Such rapid cooling can be implemented, for example, by adding pure water cooled to no more than 10°C until a desired temperature is reached. Rapid cooling makes it possible to suppress an increase in crystallite size during the cooling step.

[0092] Meanwhile, a strong processing method (a method of mechanically applying a strong force to the inorganic particles) can be used as a method for controlling the full width at half maximum (FWHM). Examples of strong processing methods include ball milling, high-pressure torsion, falling weight processing, particle impact, air-type jet peening (or shot peening), and the like.

[0093] To improve loading stability, developer performance, flowability, and durability, it is preferred that the toner of the present invention includes silicon dioxide fine powder as inorganic fine particles in addition to strontium titanate. The silicon dioxide fine powder preferably has a specific surface area of ​​at least 30 m². 2 / g and no more than 500 m 2 / g up, and more strongly preferred at least 50 m 2 / g and no more than 400 m 2 / g, as determined by a BET method based on nitrogen adsorption. The silicon dioxide fine powder content is preferably at least 0.01 parts by mass and not more than 8.0 parts by mass, and more preferably at least 0.10 parts by mass and not more than 5.0 parts by mass per 100 parts by mass of the toner particles.

[0094] It is preferred that the silicon oxide fine powder be surface-treated, as required for the purpose of controlling hydrophobicity and triboelectric charging capability, with a treatment agent such as unmodified silicone lacquers, various modified silicone lacquers, unmodified silicone oils, various modified silicone oils, silane coupling agents, silane compounds with functional groups and other organosilicon compounds, or with a combination of different treatment agents.

[0095] Other external additives can be added to the toner as needed. Examples of such external additives include resin particles or inorganic particles that act as a loading adjuvant, a conductivity enhancer, a flow enhancer, a clumping inhibitor, a release agent during hot roller curing, a lubricant, a polishing agent, and the like. Examples of lubricants include polyethylene fluoride powder, zinc stearate powder, and polyvinylidene fluoride powder. Examples of polishing agents include cerium oxide powder and silicon carbide powder.

[0096] The toner particle may contain a binder resin. Examples of binder resins are listed below.

[0097] A styrene resin, a styrene copolymer resin, a polyester resin, a polyol resin, a polyvinyl chloride resin, a phenolic resin, a natural resin-modified phenolic resin, a natural resin-modified maleic acid resin, an acrylic resin, a methacrylic resin, polyvinyl acetate, a silicone resin, a polyurethane resin, a polyamide resin, a furan resin, an epoxy resin, a xylene resin, a polyvinyl butyral resin, a terpene resin, a coumarin-indene resin, or a petroleum resin. Preferred examples of the resin include a styrene copolymer resin, a polyester resin, and a hybrid resin in which a polyester resin and a styrene-like copolymer resin are mixed or partially reacted with each other. More preferably, the binder resin includes a polyester resin.

[0098] From the perspective of storage stability, it is preferred that the glass transition temperature (Tg) of the binder resin be at least 45°C. From the perspective of low-temperature curing capability, it is preferred that Tg not exceed 75°C, and more preferably not exceed 70°C. A method for measuring the glass transition temperature will be described later.

[0099] A release agent (wax) can be used to give the toner release properties.

[0100] Examples of waxes are listed below. Aliphatic hydrocarbon waxes, such as low molecular weight polyethylene, low molecular weight polypropylene, an olefin copolymer, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxidized aliphatic hydrocarbon waxes, such as oxidized polyethylene wax; waxes composed mainly of fatty acid esters, such as carnauba wax, behenyl behenate, and montanic acid ester wax; and waxes obtained by partial or complete deacidification of fatty acid esters, such as deacidified carnauba wax.

[0101] Other examples include saturated linear fatty acids, such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids, such as brassidic acid, eleostearic acid, and varinaric acid; saturated alcohols, such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, seryl 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 methylene bis-stearic acid amide, ethylene bis-caprylic acid amide, ethylene bis-lauric acid amide, and hexamethylene bis-stearic acid amide; unsaturated fatty acid amides, such as ethylene bis-oleic acid amide, hexamethylene bis-oleic acid amide, N,N'-dioleyladipamide, and N,N'-dioleylsebacamide; aromatic bisamides, such as m-xylene bis-stearic acid amide and N,N'-distearylisophthalic acid amide;Aliphatic metal salts, such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate (generally referred to as metallic soaps); waxes obtained by grafting aliphatic hydrocarbon waxes using a vinyl-based copolymer, such as styrene and acrylic acid; partially esterified products of fatty acids and polyhydric alcohols, such as behenyl monoglycerides; methyl ester compounds with a hydroxyl group, obtained by hydrogenation of vegetable oils and the like.

[0102] The wax that is particularly preferred for use in the present invention is an aliphatic hydrocarbon wax. Preferred examples include low molecular weight hydrocarbons obtained by radical polymerization of an alkylene under high pressure or polymerization under low pressure with a Zielger catalyst or a metallocene catalyst; a Fischer-Tropsch wax synthesized from coal or natural gas; an olefin copolymer obtained by thermal decomposition of a high molecular weight olefin polymer; a synthetic hydrocarbon wax obtained from a distillation residue of a hydrocarbon obtained by an Arge process from a synthesis gas containing carbon monoxide and hydrogen; and a synthetic hydrocarbon wax obtained by hydrogenating such hydrocarbon waxes.

[0103] Furthermore, it is preferred to use a product obtained by fractionating a hydrocarbon wax by a press-wiping process or a solvent process, using vacuum distillation or by a fractional crystallization process. In particular, a wax synthesized by a process not based on the polymerization of alkylenes is preferred with regard to its molecular weight distribution.

[0104] The wax can be added during the production of the toner or the production of the binder resin. Furthermore, one type of wax can be used individually, or two or more types of wax can be used in combination. The wax is preferably added in an amount of at least 1 part by mass and not more than 20 parts by mass per 100 parts by mass of the binder resin.

[0105] The toner of the present invention can be used as any of a magnetic single-component toner, a non-magnetic single-component toner and a non-magnetic two-component toner.

[0106] When the toner is used as a magnetic one-component toner, magnetic iron oxide particles are preferably used as a colorant. Examples of magnetic iron oxide particles contained in the magnetic one-component toner include magnetic iron oxides such as magnetite, maghemite, and ferrite; magnetic iron oxides containing other metal oxides; metals such as Fe, Co, and Ni; 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 the magnetic iron oxide particles is preferably at least 30 parts by mass and not more than 100 parts by mass per 100 parts by mass of the binder resin.

[0107] Examples of the colorant for use in a non-magnetic single-component toner and a non-magnetic two-component toner are listed below.

[0108] Carbon black, such as furnace black, channel black, acetylene black, thermal black and lamp black, can be used as a black pigment, and magnetic powder, such as magnetite and ferrite, can also be used.

[0109] Pigments or dyes can be used as a colorant suitable for yellow color. 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 and 191, and CI Vat Yellow 1, 3 and 20. Examples of dyes include CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, and the like. These are used individually or in combination with two or more.

[0110] Pigments or dyes can be used as colorants suitable for cyan color. Examples of pigments include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66, and similar pigments, CI Vat Blue 6, and CI Acid Blue 45. Examples of dyes include CI Solvent Blue 25, 36, 60, 70, 93, 95, and similar pigments. These are used individually or in combination with other pigments.

[0111] Pigments or dyes can be used as suitable colorants for magenta. Examples of the 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, 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 and the like, CI Pigment Violet 19, and CI Vat Red 1, 2, 10, 13, 15, 23, 29 and 35.

[0112] 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 and the like, CI Disperse Red 9, CI Solvent Violet 8, 13, 14, 21, 27 and the like, CI Disperse Violet 1 and the like, and 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 the like, CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28 and the like. These are used individually or in combination with two or more.

[0113] The colorant content is preferably at least 1 part by mass and not more than 20 parts by mass based on 100 parts by mass of the binder resin.

[0114] A charging agent can be used in the toner. Known charging agents can be used, and examples include azo iron compounds, azochrome compounds, azo manganese compounds, azocobalt compounds, azozirconium 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.

[0115] The carboxylic acid derivative is preferably an aromatic hydrocarbon carboxylic acid. A charging control resin can also be used. If a charging control agent or a charging control resin is used, it is preferably present in an amount of 0.1 parts by mass and not more than 10 parts by mass per 100 parts by mass of the binder resin.

[0116] The toner can be mixed with a carrier and used as a two-component developer. The carrier can be a conventional substrate such as ferrite and magnetite, or a resin-coated substrate. Alternatively, a binder-type carrier core in which magnetic powder is dispersed in a resin can also be used.

[0117] The resin-coated substrate consists of a substrate particle and a coating material, which is a resin that covers (coats) the surface of the substrate particle. Examples of resins used as the coating material include styrene-acrylic resins, such as a styrene-acrylic ester copolymer and a styrene-methacrylic ester copolymer; acrylic resins, such as an acrylic ester copolymer and a methacrylic ester copolymer; fluorine-containing resins, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, and polyvinylidene fluoride; silicone resins; polyester resins; polyamide resins; polyvinyl butyral; and aminoacrylate resins. Other examples include ionomer resins and polyphenylene sulfide resins. These resins can be used individually or in combination.

[0118] The method for producing the toner is not specifically limited, and a known method, such as a pulverization process, a suspension polymerization process, and an emulsion aggregation process, may be used. The following describes the method for producing the toner using the pulverization process as an example, but this method is not the only limiting factor.

[0119] For example, a binder resin and, if required, a colorant and other additives are thoroughly mixed using a mixer, such as a Henschel mixer or a ball mill, then subjected to hot melt kneading using a thermal kneader, such as a heating roller, a kneader, and an extruder, cooled and solidified, and pulverized and classified to obtain toner particles. The toner is then obtained by sufficiently mixing the toner particles with strontium titanate or inorganic fine particles A and B, and optionally with silicon dioxide powder and the like, using a mixer, such as a Henschel mixer.

[0120] Examples of mixers are listed below. Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); SUPERMIXER (manufactured by Kawata Mfg Co., Ltd.), RIBOCONE (manufactured by Okawara Mfg. Co., Ltd.); NAUTA MIXER, TURBULIZER and CYCLOMIX (manufactured by Hosokawa Micron Corporation); SPIRAL PIN MIXER (manufactured by Pacific Machinery & Engineering Co., Ltd.); and LODIGE MIXER (manufactured by Matsubo Corporation).

[0121] Examples of kneaders are listed below. KRC kneader (manufactured by Kurimoto, Ltd.); BUSS Co-kneader (manufactured by Buss AG); TEM-type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by The Japan Steel Works, Ltd.); PCM kneader (manufactured by Ikegai Ironworks Corp.); a triple roll mill, a mixing roll mill, and a kneader (manufactured by Inoue Seisakusho Co., Ltd.); KNEADEX (manufactured by Mitsui Mining Co., Ltd.); MS-type press kneader and kneader rudder (manufactured by Moriyama Works); and Banbury mixer (manufactured by Kobe Steel, Ltd.).

[0122] Examples of pulverizers are listed below: COUNTER JET MILL, MICRON JET and INNOMIZER (manufactured by Hosokawa Micron Corporation); IDS-type mill and PJM jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); CROSS JET MILL (manufactured by Kurimoto, Ltd.); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); KRYPTRON (manufactured by EARTHTECHNICA Co., Ltd.); TURBO MILL (manufactured by Turbo Kogyo Co., Ltd.); and SUPER-ROTOR (manufactured by Nisshin Engineering Inc.).

[0123] Examples of the classifier are listed below. CLASSIEL, MICRON CLASSIFIER and SPEDIC CLASSIFIER (manufactured by Seishin Enterprise Co., Ltd.); TURBO CLASSIFIER (manufactured by Nisshin Engineering Inc.); MICRON SEPARATOR, TURBOPLEX (ATP), TSP SEPARATOR and TTSP SEPARATOR (manufactured by Hosokawa Micron Corporation); ELBOW JET (manufactured by Nittetsu Mining Co., Ltd.); DISPERSION SEPARATOR (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM MICRO CUT (manufactured by Yaskawa & Co., Ltd.).

[0124] Examples of sieving devices used for sieving coarse particles are listed below: ULTRASONIC (manufactured by Koeisangyo Co., Ltd.); RESONA-SIEVE and GYRO-SIFTER (manufactured by Tokuju Corporation); VIBRASONIC SYSTEM (manufactured by Dalton Corporation); SONICLEAN (manufactured by Sintokogio, Ltd.); TURBO SCREENER (manufactured by Turbo Kogyo Co., Ltd.); MICRO SHIFTER (manufactured by Makino Mfg. Co., Ltd.); and a circular vibrating sieve.

[0125] Next, methods for measuring physical properties according to the invention will be described. X-ray diffraction measurement

[0126] The measurement is performed using a MiniFlex 600 (manufactured by Rigaku Corporation) under the following conditions.

[0127] A sample is placed on a non-reflective sample plate (manufactured by Rigaku Corporation) without diffraction peaks within the measurement area, while the inorganic fine particles (strontium titanate) are lightly compressed to achieve a flat configuration and maintain a powder state. The flattened particles are then transferred to the apparatus along with the sample plate. Measurement conditions of X-ray diffraction Tube: Cu Parallel beam optical system Voltage: 40 kV Current: 15 mA Starting angle: 3° Closing angle: 60° Scanning step size: 0.02° Scanning speed: 10.00° / min Divergence gap: 0.625° Scattering gap: 8.0 mm Receiving gap: 13.0 mm (open)

[0128] The half-width and peak intensity of the obtained diffraction peak are calculated using the analysis software “PDXL”, manufactured by Rigaku Corporation. X-ray gene fluorescence measurement

[0129] If the surface treatment is carried out with a silane coupling agent or the like, the X-ray fluorescence measurement of the inorganic fine particles (strontium titanate or inorganic fine particles A) is carried out before the surface treatment.

[0130] Elements from Na to U in inorganic fine particles are measured directly under a helium atmosphere using an Axios advanced wavelength-dispersive X-ray fluorescence analyzer (manufactured by Spectris Co., Ltd.). A liquid sample tray supplied with the instrument is used, a polypropylene (PP) film is stretched across the bottom, a sufficient quantity of sample is introduced, a layer of uniform thickness is formed on the bottom, and the tray is sealed with a lid. The measurement is performed under a power condition of 2.4 kW. A fundamental parameter (FP) method is used for the analysis. It is assumed that all detected elements are present in oxide form, and their total mass is assumed to be 100% by mass.The content (mass%) of strontium oxide (SrO) and titanium oxide (TiO2) based on the total mass is determined as an oxide equivalent value in the software UniQuant 5 (version 5.49) (manufactured by Spectris Co., Ltd.).

[0131] Measurement of the number-mean particle diameter of primary particles of inorganic fine particles

[0132] The number-mean particle diameter of the primary particles of the inorganic fine particles (strontium titanate, inorganic fine particles A and B) is determined by observation with a transmission electron microscope “H-800” (manufactured by Hitachi, Ltd.), in which a principal diameter of 100 primary particles is measured in a field magnified 2,000,000 times, and their number-mean particle diameter is determined. Measurement of the amount of water adsorption

[0133] The amount of water adsorption of the inorganic particles (strontium titanate or inorganic fine particles A) is measured using a “High-precision vapor adsorption amount measuring device BELSORP-aqua 3” (Nippon Bell Co., Ltd.).

[0134] In the “High-precision vapor adsorption amount measuring device BELSORP-aqua 3”, a solid-gas equilibrium is achieved under the condition that only the target gas (water in the case of the present invention) is present, and the solid mass and vapor pressure are measured.

[0135] First, approximately 0.5 g of a sample is introduced into a sample cell and degassed for 24 hours at room temperature under 100 Pa. After degassing is complete, the sample mass is precisely weighed, the sample is transferred to the main body of the device, and the measurement is performed under the following conditions. - Air thermostat temperature: 80.0°C - Adsorption temperature: 30.0°C - Adsorbant name: H2O - Equilibration time: 500 sec. - Waiting for the temperature to reach 60 min. - Saturated vapor pressure: 4.245 kPa - Sample tube ejection velocity: Normal - Insertion pressure, initial insertion volume: 0.20 cm 3 (STP) · g -1 - Measurement relative pressure range P / P0 (measurement of the adsorption process): 0.05; 0.15; 0.25; 0.35; 0.45; 0.55; 0.65; 0.75; 0.85; 0.90; 0.95

[0136] The measurement is carried out under the above-mentioned conditions, a moisture adsorption / desorption isotherm is plotted at a temperature of 30°C and the amount of water adsorption (mg / g) per 1 g sample at a humidity of 80% RH in the adsorption process is calculated. Measurement of the weight-averaged particle diameter (D4) of the toner

[0137] A precision particle diameter distribution device, the "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), equipped with a 100 µm aperture tube, is used as the measuring instrument. The accompanying specialized software, "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.), is used to set the measurement conditions and analyze the measurement data. The measurement is performed with 25,000 effective measurement channels.

[0138] A solution is prepared by dissolving special grade sodium chloride in ion exchange water to a concentration of about 1% by mass; for example, “Isoton II” (manufactured by Beckman Coulter, Inc.) can be used as an electrolytic aqueous solution for measurement.

[0139] Before measurement and analysis, the associated software is configured as follows.

[0140] On the "CHANGE STANDARD MEASUREMENT METHOD" screen of the associated software, the total count in control mode is set to 50,000 particles, the number of measurement cycles is set to one, and the value obtained using "STANDARD PARTICLES 10.0 µm" (manufactured by Beckman Coulter, Inc.) is set as a Kd value. The measurement limit and noise level are automatically set by pressing the "THRESHOLD / NOISE LEVEL MEASUREMENT BUTTON". Furthermore, the current is set to 1600 µA, the gain is set to 2, the electrolytic solution is set to ISOTON II, and "FLUSH APERTURE TUBE AFTER MEASUREMENT" is selected.

[0141] In the "Setting Conversion from Pulse to Particular Diameter" screen of the associated software, the container interval is set to a logarithmic particle diameter, the particle diameter container is set to 256 particle diameter containers, and the particle diameter range is set to 2 µm to 60 µm.

[0142] Specific measurement methods are as follows.

[0143] (1) Approximately 200 ml of the electrolytic solution is placed in a 250 ml round-bottomed beaker designed for Multisizer 3, the beaker is inserted into the sample holder, and stirring with a stirring rod is performed counterclockwise at 24 revolutions per second. Dirt and air bubbles in the aperture tube are removed by pressing the "FLUSH OF APERTURE" function button in the associated software.

[0144] (2) Approximately 30 ml of the electrolytic aqueous solution are placed in a 100 ml flat-bottomed beaker. Then, as a dispersant, approximately 0.3 ml of a dilute solution obtained by diluting “Contaminon N” (10 wt% aqueous solution of a neutral detergent for washing precision measuring instruments at pH 7, consisting of a non-ionic surfactant, an anionic surfactant and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) with ion-exchange water to approximately three times the dilution is added.

[0145] (3) An ultrasonic dispersion system “Ultrasonic Dispersion System Tetora 150” (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output power of 120 W, in which two oscillators with an oscillation frequency of 50 kHz and a phase shift of 180° are installed, is prepared. Approximately 3.3 liters of ion exchange water are placed in the water tank of the ultrasonic dispersion system and 2 ml of Contaminon N are added to the water tank.

[0146] (4) The beaker from (2) above is placed in the beaker fixing opening of the ultrasonic disperser and the ultrasonic disperser is activated. Then the height position of the beaker is adjusted so that the resonance state of the liquid surface of the electrolytic aqueous solution in the beaker is maximized.

[0147] (5) Approximately 10 mg of the toner are added piece by piece to the electrolytic aqueous solution and dispersed in it in such a state that the electrolytic solution in the beaker of (4) above is irradiated with ultrasonic waves. The ultrasonic dispersion process is then continued for a further 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is adjusted to at least 10°C and not more than 40°C.

[0148] (6) The electrolytic aqueous solution from (5) above, in which the toner is dispersed, is added dropwise using a pipette to the round-bottomed beaker from (1) above, which was inserted into the sample holder, and the measurement concentration is adjusted to approximately 5%. The measurement is then carried out until the number of particles to be measured reaches 50,000.

[0149] (7) The measurement data are analyzed using the associated software provided with the device, and the weight-averaged particle diameter (D4) and the number-mean particle diameter (D1) are calculated. The "AVERAGE DIAMETER" displayed on the "ANALYSIS / VOLUME STATISTICAL VALUE (ARITHMETIC MEAN)" screen, obtained when Graph / Volume % is selected in the associated software, is the weight-averaged particle diameter (D4), and the "AVERAGE DIAMETER" displayed on the "ANALYSIS / NUMERICAL STATISTICAL VALUE (ARITHMETIC MEAN)" screen, obtained when Graph / Number % is selected in the associated software, is the number-mean particle diameter (D1). Method for measuring the glass transition temperature (Tg) of toner particles or binder resin

[0150] The glass transition temperature (Tg) of the toner particle or binder resin is measured at ambient temperature and humidity in accordance with ASTM D3418-82 using a differential scanning calorimeter (DSC), MDSC-2920 (manufactured by TA Instruments). Approximately 3 mg of a sample is precisely weighed and used. The sample is placed in an aluminum pan, and an empty aluminum pan is used as a reference. The temperature range is set to at least 30°C and not more than 200°C. The temperature is increased from 30°C to 200°C at a rate of 10°C / minute, then decreased from 200°C to 30°C at a rate of 10°C / minute, and finally increased again to 200°C at a rate of 10°C / minute.

[0151] In the DSC curve obtained during the second temperature increase process, the intersection of the line at the midpoint of the baseline, before and after the specific heat change occurs, and the differential thermal curve is taken as the glass transition temperature Tg. Methods for measuring Et

[0152] A powder flowability analyzer (Powder Rheometer FT-4, manufactured by Freeman Technology) (hereinafter also referred to as “FT -4”) equipped with a rotating blade is used to measure Et.

[0153] The principle of the device is to move the rotating blade through a powder sample, creating a constant flow pattern. The particles in the powder sample flow when the blade is near them and remain stationary after the blade has passed. The energy required to move the blade through the powder is measured, and various flow indices are calculated from this energy value. The blade is of the propeller type and moves up and down while rotating, so that the blade tip traces a spiral. By changing the rotational speed and the vertical movement, it is possible to adjust the angle and speed of the blade's spiral path. When the blade is moved clockwise along the spiral with respect to the surface of the powder layer, it acts in such a way that it mixes the powder uniformly.Conversely, if the sheet is moved counterclockwise along the spiral path with respect to the surface of the powder layer, the sheet experiences resistance from the powder.

[0154] Specifically, the measurement is performed using the following procedure. In all procedures, a blade with a diameter of 48 mm, specially designed for measurement with the FT-4 (the axis of rotation lies in the normal direction at the center of a 48 mm x 10 mm blade plate; the blade plate is slightly tilted counterclockwise so that the outermost edge sections (sections 24 mm from the rotating shaft) are at 70° and a section 12 mm from the rotating shaft is at 35°; the blade material is SUS. Model number: C210. ​​Hereinafter also referred to as "blade"), is used as the propeller-like blade.

[0155] First, a toner powder layer is obtained by placing 100 g of the toner, which has been left to stand for at least 3 days at 23°C and 60% ambient temperature, in a 50 mm x 160 ml separation container specifically designed for measurement with FT-4 (model number: C 203; height from the bottom of the container to the separation area is 82 mm; the material is glass; also referred to below as the "container"). (1) Conditioning plant (a) The rotational speed of the sheet (the peripheral speed of the outermost edge of the sheet) is set to 60 mm / sec. The speed of entry into the powder layer in the vertical direction is adjusted so that the angle formed between the locus traced by the outermost edge of the moving sheet and the surface of the powder layer (hereinafter also referred to as the “formed angle”) is 5 degrees. The sheet is inserted from the surface of the powder layer to a position of 10 mm from the bottom surface of the toner powder layer in the clockwise direction of rotation (the direction in which the powder layer is loosened by the rotation of the sheet) with respect to the surface of the powder layer.The process then involves inserting the sheet to a position 1 mm from the surface of the toner powder layer in a clockwise rotation direction relative to the surface of the powder layer, at a sheet rotation speed of 60 mm / sec. The entry speed into the powder layer is vertical, resulting in an angle of 2 degrees. The sheet is then moved to a position 100 mm from the bottom surface of the toner powder layer and withdrawn in a clockwise rotation direction relative to the surface of the powder layer, at a sheet rotation speed of 60 mm / sec. The withdrawal speed is such that the angle formed is 5 degrees. Once withdrawn, the sheet is rotated slightly alternately clockwise and counterclockwise to shake off any toner adhering to it. (b) By performing procedure (1)-(a) five times, air introduced into the toner powder layer is removed and a stable toner powder layer is produced. (2) Separate operation

[0156] The toner powder layer is scraped off by the separating section (or cutting section) of a cell specifically designed for measurement with FT-4, and the toner on the upper part of the toner powder layer is removed to form a toner powder layer of equal volume. (3) Measurement operation (a) The same procedure as in (1)-(a) above is carried out once. (b) Next, the rotational speed of the sheet is set to 100 mm / sec, and the vertical entry speed into the toner powder layer is adjusted so that the resulting angle is 5 degrees. The sheet is advanced counterclockwise (in the direction in which the toner powder layer is forced in by the rotation of the sheet) with respect to the surface of the powder layer until it reaches a position of 10 mm from the bottom surface of the toner powder layer. Then, the sheet is advanced clockwise to a position of 1 mm from the bottom surface of the toner powder layer, at a rotational speed of 60 mm / sec and a vertical entry speed such that the resulting angle is 2 degrees.The sheet is then withdrawn to a position 100 mm from the base of the toner powder layer in a clockwise rotation direction relative to the surface of the powder layer, at a sheet rotation speed of 60 mm / sec. The withdrawal speed from the powder layer is vertical, such that the angle formed is 5 degrees. Once the withdrawal is complete, the sheet is rotated slightly alternately clockwise and counterclockwise to shake off any toner adhering to the sheet. (c) The sequence of procedure (b) is repeated seven times.

[0157] A total Et of a rotational torque and a vertical load (or vertical stress) obtained when the sheet is advanced from a position of 100 mm to a position 10 mm from the bottom surface of the toner powder layer at a rotational speed of the sheet in the seventh cycle of 100 (mm / sec) in procedure (c) above, is used as Et (mJ). Examples

[0158] The invention of the present application will below be described specifically based on examples. However, the invention of the present application is not limited to these examples. In the examples provided, parts and percentages are given on a mass basis unless otherwise stated.

[0159] The first aspect of the present invention will be described with reference to examples. Production example of strontium titanate A-1

[0160] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 50 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0161] A 1.3-fold molar amount of aqueous strontium chloride solution was added to 2.2 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Furthermore, pure water was added to obtain 1.1 mol / L based on titanium oxide.

[0162] Next, after stirring, mixing, and heating to 90°C, 440 ml of a 10 N aqueous sodium hydroxide solution was added over 15 minutes while ultrasonic vibration was applied, and the reaction was then carried out for 20 minutes. Pure water at 5°C was added to the slurry after the reaction, the slurry was rapidly cooled to no more than 30°C, and the supernatant was then removed. Furthermore, an aqueous hydrogen chloride solution with a pH of 5.0 was added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0163] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, followed by the addition of isobutyltrimethoxysilane at 7.0 wt% based on the solids content of the slurry, and stirring for 10 hours. The mixture was then neutralized with aqueous sodium hydroxide solution, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-1. The physical properties are shown in Table 1. Production example of strontium titanate A-2

[0164] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 50 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0165] A 1.2-fold molar amount of aqueous strontium chloride solution was added to 2.6 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Purified water was then added to achieve a titanium oxide concentration of 1.3 mol / L.

[0166] Next, after stirring, mixing, and heating to 95°C, 312 ml of a 15 N aqueous sodium hydroxide solution was added over 5 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. Pure water at 5°C was added to the slurry after the reaction, the slurry was rapidly cooled to no more than 30°C, and the supernatant was then removed. Furthermore, an aqueous hydrogen chloride solution with a pH of 5.0 was added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0167] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, followed by the addition of isobutyltrimethoxysilane at 5.0 wt% based on the solids content of the slurry. The mixture was then stirred for 10 hours. Afterward, neutralization with aqueous sodium hydroxide solution was carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-2. The physical properties are shown in Table 1. Production example of strontium titanate A-3

[0168] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 50 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0169] A 1.2-fold molar amount of aqueous strontium chloride solution was added to 2.0 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Purified water was then added to achieve a titanium oxide concentration of 1.0 mol / L.

[0170] Next, after stirring, mixing, and heating to 85°C, 800 ml of a 5 N aqueous sodium hydroxide solution was added over 20 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. Pure water at 5°C was added to the slurry after the reaction, the slurry was rapidly cooled to no more than 30°C, and the supernatant was then removed. An aqueous hydrogen chloride solution with a pH of 5.0 was then added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0171] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, followed by the addition of isobutyltrimethoxysilane at 30.0 wt% based on the solids content of the slurry. The mixture was then stirred for 10 hours. Afterward, neutralization with aqueous sodium hydroxide solution was carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-3. The physical properties are shown in Table 1. Production example of strontium titanate A-4

[0172] Strontium titanate A-4 was prepared in the same manner as strontium titanate A-3, except that 4.0 wt% n-octyltriethoxysilane was used instead of isobutyltrimethoxysilane. Physical properties are shown in Table 1. Production example of strontium titanate A-5

[0173] Strontium titanate A-5 was prepared in the same manner as strontium titanate A-4, except that the amount of n-octyltriethoxysilane added was changed to 2.0 wt%. The physical properties are shown in Table 1. Production example of strontium titanate A-6

[0174] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 70 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0175] A 1.1-fold molar amount of aqueous strontium chloride solution was added to 1.8 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Furthermore, pure water was added to obtain a titanium oxide concentration of 0.9 mol / L.

[0176] Next, after stirring, mixing, and heating to 85°C, 576 ml of a 5 N aqueous sodium hydroxide solution was added over 5 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. Pure water at 5°C was added to the slurry after the reaction, the slurry was rapidly cooled to no more than 30°C, and the supernatant was then removed. Furthermore, an aqueous hydrogen chloride solution with a pH of 5.0 was added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0177] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and n-octyltriethoxysilane was added at 2.0 wt% based on the solids content of the slurry, followed by stirring for 10 hours. Neutralization with aqueous sodium hydroxide solution was then carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-6. The physical properties are shown in Table 1. Production example of strontium titanate A-7

[0178] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 70 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0179] A 1.1-fold molar amount of aqueous strontium chloride solution was added to 1.8 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Furthermore, pure water was added to obtain a titanium oxide concentration of 0.9 mol / L.

[0180] Next, after stirring, mixing, and heating to 80°C, 792 ml of a 5 N aqueous sodium hydroxide solution was added over 40 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. The post-reaction slurry was gradually cooled to no more than 30°C for 1 hour, and the supernatant was then removed. An aqueous hydrogen chloride solution with a pH of 5.0 was then added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0181] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and n-octyltriethoxysilane was added at 2.0 wt% based on the solids content of the slurry, followed by stirring for 10 hours. Neutralization with aqueous sodium hydroxide solution was then carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-7. The physical properties are shown in Table 1. Production example of strontium titanate A-8

[0182] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 100 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0183] A 1.1-fold molar amount of aqueous strontium chloride solution was added to 1.4 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Furthermore, pure water was added to obtain a titanium oxide concentration of 0.7 mol / L.

[0184] Next, after stirring, mixing, and heating to 80°C, 1000 ml of a 3N aqueous sodium hydroxide solution was added over 40 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. The post-reaction slurry was gradually cooled to no more than 30°C for 1 hour, and the supernatant was then removed. An aqueous hydrogen chloride solution with a pH of 5.0 was then added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0185] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and n-octyltriethoxysilane was added at 2.0 wt% based on the solids content of the slurry, followed by stirring for 10 hours. Neutralization with aqueous sodium hydroxide solution was then carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-8. The physical properties are shown in Table 1. Production example of strontium titanate A-9

[0186] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 100 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0187] A 1.1-fold molar amount of aqueous strontium chloride solution was added to 1.0 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Purified water was then added to achieve a titanium oxide concentration of 0.5 mol / L.

[0188] Next, after stirring, mixing, and heating to 70°C, 1100 ml of a 2N aqueous sodium hydroxide solution was added over 40 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. The post-reaction slurry was gradually cooled to no more than 30°C for 1 hour, and the supernatant was then removed. An aqueous hydrogen chloride solution with a pH of 5.0 was then added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water was then repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0189] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and n-octyltriethoxysilane was added at 2.0 wt% based on the solids content of the slurry, followed by stirring for 10 hours. Neutralization with aqueous sodium hydroxide solution was then carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-9. The physical properties are shown in Table 1. Production example of strontium titanate A-10

[0190] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 100 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0191] A 1.1-fold molar amount of aqueous strontium chloride solution was added to 1.0 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Purified water was then added to achieve a titanium oxide concentration of 0.5 mol / L.

[0192] Next, after stirring, mixing, and heating to 70°C, 1200 ml of a 2N aqueous sodium hydroxide solution was added over 240 minutes, and the reaction was then carried out for 20 minutes. The slurry after the reaction was gradually cooled to no more than 30°C for 1 hour, and the supernatant was then removed. An aqueous hydrogen chloride solution with a pH of 5.0 was then added to the slurry, followed by stirring for 1 hour to dissolve and remove strontium carbonate. Washing with pure water and drying were then carried out to obtain inorganic fine particles (a). The full width at half maximum (FWHM) of the inorganic fine particles (a) was 0.15. The inorganic fine particles (a) were then placed together with 4 mm aluminum oxide spheres in an automatically unloading ball mill (manufactured by Eishin Co., Ltd.) and stirred for 200 hours.The aluminum oxide spheres were then removed and purified, and after drying, the resulting inorganic fine particles were subjected to X-ray diffraction and X-ray fluorescence measurements. Their physical properties are shown in Table 1.

[0193] Next, the inorganic particles were placed in a closed-type, high-speed stirrer and stirred under nitrogen purge. A treatment agent, obtained by diluting dimethyl silicone oil (taken at 4 wt% of the solids content of the slurry) 6.5-fold with hexane, was sprayed into the stirrer. After the entire amount of treatment agent had been sprayed, the inside of the stirrer was heated to 350°C while stirring, and stirring was continued for 3 hours. The internal temperature of the stirrer was then returned to room temperature while stirring, and the mixture was removed and subsequently pulverized by a pin mill to obtain strontium titanate A-10. Physical properties are shown in Table 1. Production example of strontium titanate A-11

[0194] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 100 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0195] A 1.0-molar amount of aqueous strontium chloride solution was added to 1.0 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Furthermore, pure water was added to obtain a titanium oxide concentration of 0.5 mol / L.

[0196] Next, after stirring, mixing, and heating to 70°C, 1100 ml of a 2N aqueous sodium hydroxide solution was added over 40 minutes while ultrasonic vibrations were applied, and the reaction was then carried out for 20 minutes. The post-reaction slurry was gradually cooled to no more than 30°C for 1 hour, and the supernatant was then removed. Washing with pure water was repeated, a portion of the resulting cake was taken as a sample and dried, and X-ray diffraction and X-ray fluorescence measurements were subsequently performed. The results are shown in Table 1.

[0197] Subsequently, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and n-octyltriethoxysilane was added at 1.0 wt% based on the solids content of the slurry, followed by stirring for 10 hours. Neutralization with aqueous sodium hydroxide solution was then carried out, followed by filtration through a Büchner funnel and washing with pure water. The resulting cake was dried to obtain strontium titanate A-11. The physical properties are shown in Table 1. Production example of strontium titanate A-12

[0198] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 100 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0199] A 1.0-molar amount of aqueous strontium chloride solution was added to 0.6 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Purified water was then added to achieve a titanium oxide concentration of 0.3 mol / L.

[0200] Next, after stirring, mixing, and heating to 70°C, 750 ml of a 2N aqueous sodium hydroxide solution was added over 120 minutes, and the reaction was then carried out for 20 minutes. The slurry after the reaction was gradually cooled to no more than 30°C for 1 hour, and the supernatant was then removed. The slurry was then washed with pure water and dried, and X-ray diffraction and X-ray fluorescence measurements of the resulting inorganic fine particles were subsequently performed. The results are shown in Table 1.

[0201] Next, the inorganic particles were placed in a closed-type, high-speed stirrer and stirred under nitrogen purge. A treatment agent, obtained by diluting dimethyl silicone oil (taken at 2 wt% based on the solids content of the slurry) 6.5-fold with hexane, was sprayed into the stirrer. After the entire amount of treatment agent had been sprayed, the inside of the stirrer was heated to 350°C while stirring, and stirring was continued for 3 hours. The internal temperature of the stirrer was then returned to room temperature while stirring, and the mixture was removed and subsequently pulverized by a pin mill to obtain strontium titanate A-12. Physical properties are shown in Table 1. Production example of strontium titanate A-13

[0202] An aqueous titanium dioxide slurry, obtained by hydrolyzing an aqueous titanyl sulfate solution, was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant reached 200 µS / cm to reduce the amount of impurities and purify the slurry. Hydrochloric acid was then added to the aqueous titanium dioxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion.

[0203] A 1.0-molar amount of aqueous strontium chloride solution was added to 0.6 mol (based on titanium oxide) of the titanium oxide sol dispersion, and the dispersion was transferred to a reaction vessel and purged with nitrogen gas. Furthermore, 0.05 mol of aluminum sulfate was added, followed by the addition of pure water to achieve a titanium oxide concentration of 0.3 mol / L.

[0204] Next, after stirring, mixing, and heating to 70°C, 450 ml of a 2N aqueous sodium hydroxide solution was added over 5 minutes, and the reaction was then carried out for 20 minutes. Pure water at 5°C was added to the slurry after the reaction, the slurry was rapidly cooled to no more than 30°C, and the supernatant was then removed. The slurry was then washed with pure water and dried, and X-ray diffraction and X-ray fluorescence measurements of the resulting inorganic fine particles were subsequently performed. The results are shown in Table 1.

[0205] Next, the inorganic particles were placed in a closed-type, high-speed stirrer and stirred under nitrogen purge. A treatment agent, obtained by diluting dimethyl silicone oil (taken at 2 wt% based on the solids content of the slurry) 6.5-fold with hexane, was sprayed into the stirrer. After the entire amount of treatment agent had been sprayed, the inside of the stirrer was heated to 350°C while stirring, and stirring was continued for 3 hours. The internal temperature of the stirrer was then returned to room temperature while stirring, and the mixture was removed and subsequently pulverized by a pin mill to obtain strontium titanate A-13. Physical properties are shown in Table 1.

[0206] The strontium titanates A-1 to A-13 exhibit a maximum peak (A) at a diffraction angle (2θ) of at least 32.00 degrees and not more than 32.40 degrees in CuKα characteristic X-ray diffraction. [Table 1] Strontium titanate No. Average particle diameter (nm) Half-width of the maximum peak (a) (degrees) (Ix) / (Ia) Total content of SrO and TiO2 (mass %) Moisture adsorption rate (mg / g) A-1 35 0,33 0,006 98,5 15 A-2 10 0,40 0,008 98,5 20 A-3 50 0,28 0,008 98,4 1 A-4 50 0,28 0,008 98,4 25 A-5 50 0,28 0,008 98,4 40 A-6 50 0,50 0,010 98,2 40 A-7 50 0,23 0,010 98,2 40 A-8 70 0,23 0,010 98,0 40 A-9 95 0,23 0,010 98,0 40 A-10 95 0,23 0,010 98,0 40 A-11 95 0,23 0,013 98,0 45 A-12 100 0,18 0,013 98,0 45 A-13 110 0,55 0,016 96,4 47

[0207] Production example of binder resin A-1 - Bisphenol A ethylene oxide (2.2 mol adduct): 60.0 mol parts - Bisphenol A propylene oxide (2.2 mol adduct): 40.0 mol parts - Terephthalic acid: 100.0 mol parts

[0208] A total of 100 parts of the monomers that make up the polyester unit were placed in a 5-liter autoclave. A reflux condenser, a moisture separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were connected, and a polycondensation reaction was carried out at 230°C with the introduction of nitrogen gas into the autoclave. After completion of the reaction, the product was removed from the vessel, cooled, and pulverized to obtain a binder resin A-1. Example A-1

[0209] Production example of toner A-1 - Binder resin A-1: ​​100 parts - Fischer-Tropsch wax: 5 parts (melting point 105°C) - Magnetic iron oxide particles: 90 parts (number-average particle diameter 0.20 µm, Hc (coercive force) = 10 kA / m, es (saturation magnetization) = 83 Am 2 / kg, σr (residual magnetization) = 13 Am 2 / kg) - Aluminum compound of 3,5-di-tert-butyl salicylic acid: 1 part

[0210] The above materials were premixed using a Henschel mixer and melt-kneaded using a twin-screw kneading extruder.

[0211] The resulting kneaded product was cooled, coarsely pulverized using a hammer mill, and then pulverized using a jet mill. The resulting fine powder was classified using a multi-compartment unclassifier employing the Coanda effect, yielding negatively triboelectrically charged toner particles with a weight-averaged particle diameter (D4) of 6.8 µm. The Tg of the toner particles was 60°C. One part strontium titanate A-1 and one part hydrophobic silicon dioxide fine powder (specific surface area, determined by nitrogen adsorption measurement using the BET method, was 140 m²) were added to 100 parts of the toner particles. 2 / g) added externally and mixed with a Henschel mixer.

[0212] Regarding the external addition and mixing, the cold water temperature and flow rate in the cooling water jacket attached to the processing apparatus were adjusted to control the toner's flowability, while the temperature inside the mixer tank was monitored to set it to 45°C and control the adhesion of the external additive. Subsequent sieving with a 150 µm mesh sieve produced toner A-1. The physical properties of toner A-1 are shown in Table 1.

[0213] The evaluation was performed by modifying the processing speed of a commercially available digital copier (image RUNNER 4051, manufactured by Canon Corp.) to 252 mm / s. CS-680 (68.0 g / m²) 2Paper (A4) (marketed by Canon Marketing Japan Inc.) was used as the evaluation paper. Additionally, an image with a print percentage of 5% was used as an output image in the durability test. Evaluation of the husk ghost image in low-temperature and low-humidity environments

[0214] A ghost image of a pod was evaluated in the following manner in a low temperature and low humidity environment (15°C, 10% RH).

[0215] A full-surface halftone image was produced with the same order as the 1000th sheet after passing 999 continuous test samples, each separated by a vertical band of solid black and solid white outside the vertical band, as in Fig. 1 shown, were set up, cleverly.

[0216] In the halftone image, the image density of the area (a) where the solid black vertical band was located and of the area (b) where the completely white band was located was measured. Fig. 2 was measured, and the case ghost image was evaluated based on the difference in density. Areas (a) and (b) are the areas of the first turn of the case.

[0217] Image density was measured using an X-Rite color reflection densitometer (manufactured by X-Rite Incorporated; X-rite 500 Series). A: The difference in image density between area (a) and area (b) is less than 0.02; B: The difference in image density between area (a) and area (b) is at least 0.02 and less than 0.04; C: The difference in image density between area (a) and area (b) is at least 0.04 and less than 0.06; D: The difference in image density between area (a) and area (b) is at least 0.06 and less than 0.10.

[0218] Evaluation of the pod ghost image in a high-temperature and high-humidity environment.

[0219] A ghost image was evaluated in a high-temperature and high-humidity environment (32.5°C, 80% RH) as follows. After performing a continuous feed test of up to 100,000 images at a print percentage of 5%, a full-area halftone image in the same job was obtained on the 1000th sheet after passing 999 continuous test samples, each consisting of a vertical band of solid black and solid white outside the vertical band, as in Fig. 1 shown, were set up, cleverly.

[0220] In the halftone image, the image density of the area (a) where the solid black vertical band was located and of the area (b) where the completely white band was located was measured. Fig. 2 was measured, and the case ghost image was evaluated based on the difference in density. Areas (a) and (b) are the areas of the first turn of the case.

[0221] Image density was measured using an X-Rite color reflection densitometer (manufactured by X-Rite Incorporated; X-rite 500 Series). A: The difference in image density between area (a) and area (b) is less than 0.02; B: The difference in image density between area (a) and area (b) is at least 0.02 and less than 0.04; C: The difference in image density between area (a) and area (b) is at least 0.04 and less than 0.06; D: The difference in image density between area (a) and area (b) is at least 0.06 and less than 0.10. Evaluation of point reproducibility

[0222] The evaluation of dot reproducibility was performed by printing one halftone image of an isolated single dot on A4 paper after outputting 100,000 sheets under a high-temperature and high-humidity environment (32.5°C, 80% RH). Using a VHX-500 digital microscope (lens range zoom lens VH-Z 100, manufactured by Keyence Corporation), the area of ​​1000 dots was measured. The number-mean (S) of the dot area and the standard deviation (σ) of the dot area were calculated, and the dot reproducibility index was calculated using the following equation. Point reproducibility index(I) = α / S × 100

[0223] The smaller the point reproducibility index (I), the better the point reproducibility. A: I is less than 2.0; B: I is at least 2.0 and less than 3.0; C: I is at least 3.0 and less than 5.0; D: I is at least 5.0 and less than 7.0. Fine line reproducibility

[0224] Fine line reproducibility was evaluated by printing images onto 100,000 sheets under a high-temperature and high-humidity environment (32.5°C, 80% RH) and then printing one image (print percentage: 4%) in which a grid pattern with a line width of 3 pixels was printed across the entire surface of an A4 sheet of paper. Fine line reproducibility was selected according to the following evaluation criteria. The theoretical line width of 3 pixels is 127 µm. The line width of the image was measured using a VK-8500 microscope (manufactured by Keyence Corporation). The line width was measured by selecting 5 random points, and if the average value of the three points, excluding the minimum and maximum values, was taken as d (µm), the following L was defined as the fine line reproducibility index. L(μm)=|127−d|

[0225] L is defined as the difference between the theoretical line width of 127 µm and the line width d of the output image. Since d can be larger or smaller than 127 µm, it is defined as the absolute value of the difference. A smaller L indicates better fine line reproduction. Evaluation criteria A: L is at least 0 µm and less than 5 µm; B: L is at least 5 µm and less than 10 µm; C: L is at least 10 µm and less than 15 µm; D: L is at least 15 µm and less than 20 µm; Image density

[0226] An original image containing five solid black spots, each 20 mm square, arranged within a developer area was used as the image for evaluation. A continuous paper feed test was performed with up to 100,000 images at a printing rate of 5% under normal temperature and humidity conditions (23°C, 55% RH). After outputting 100,000 sheets, the original image containing the five solid black spots, each 20 mm square, within the developer area was output, and the average of the five spots was used to determine the image density.

[0227] Image density was measured using an X-Rite color reflection densitometer (manufactured by X-rite, Incorporated; X-rite 500 series). A: Image density is at least 1.45; B: Image density is at least 1.40 and less than 1.45. Veil formation

[0228] For the fogging evaluation, a continuous paper feed test of up to 100,000 images was performed at a print rate of 5% under normal temperature and humidity conditions (23°C, 55% RH). A completely white image was then evaluated according to the following criteria. The measurement was performed using a reflectometer (reflectometer model TC-6DS, manufactured by Tokyo Denshoku Co., Ltd.). The worst value of the white background reflectance after image generation was denoted as Ds, the average reflectance of the transfer material before image generation was denoted as Dr, and Dr-Ds was used as a fogging quantity to evaluate the fogging. Therefore, the smaller the numerical value, the less fogging occurs. Evaluation criteria A: Veiling is less than 1.0; B: Veiling is at least 1.0 and less than 2.0.

[0229] The toner A-1 from example A-1 received a rating of A in each of the above evaluation points. Production examples of toners A-2 to A-11

[0230] Toners A-2 to A-11 were obtained in the same manner as in the production example of toner A-1, except that the weight-averaged particle diameter of the toner, the type and amount of strontium titanate added, the amount of hydrophobic silicon dioxide fine powder added, and the temperature inside the mixer tank when toner particles, strontium titanate, and hydrophobic silicon dioxide fine powder were added externally were changed as shown in Table 2. Examples A-2 to A-11

[0231] Toner cartridges A-2 to A-11 were evaluated in the same way as in example A-1. The evaluation results are shown in Table 3. [Table 2] Toner No. Weight-averaged particle diameter (µm) Strontium titanate no. Temperature in the tank (°C) Tg - (Temperature in the tank) (°C) Amount of strontium titanate added (parts) Amount added of hydrophobic silicon dioxide fine powder (parts) Et (mJ) A-1 6,8 A-1 45 -15 1,0 1,0 400 A-2 7,5 A-1 45 -15 0,8 1,0 500 A-3 6,1 A-2 42 -18 1,5 1,0 200 A-4 6,1 A-3 47 -13 0,1 1,0 1000 A-5 6,1 A-4 47 -13 0,1 1,0 1000 A-6 6,1 A-5 47 -13 0,1 1,0 1000 A-7 6,1 A-6 40 -20 2,0 2,0 100 A-8 6,1 A-7 50 -10 0,05 0,5 2000 A-9 8,0 A-8 50 -10 0,05 0,5 2000 A-10 5,5 A-9 50 -10 0,05 0,5 2000 A-11 9,0 A-10 50 -10 0,04 0,5 2000 Comparison examples A-1 to A-3; Production example of toners A-12 to A-14

[0232] Toners A-12 to A-14 were obtained in the same way as in the production example of toner A-1, except that the weight-averaged particle diameter of the toner, the type and amount of strontium titanate added, and the amount of hydrophobic silicon dioxide powder added were changed as shown in Table 4. [Table 4] Toner No. Weight-averaged particle diameter (µm) Strontium titanate no. Temperature in the tank (°C) Tg - (Temperature in the tank) (°C) Amount of strontium titanate added (parts) Amount added of hydrophobic silicon dioxide fine powder (parts) Et (mJ) A-12 9,0 A-11 50 -10 0,04 0,5 2000 A-13 9,0 A-12 55 -5 0,02 0,4 2100 A-14 9,0 A-13 35 -25 2,1 2,2 90

[0233] Toner cartridges A-12 to A-14 were evaluated in the same way as in example A-1. The evaluation results are shown in Table 5.

[0234] Next, the second aspect of the present invention will be described with reference to examples. Production example of inorganic fine particles B-1

[0235] A total of 1500 parts strontium titanate and 800 parts titanium oxide were wet-mixed in a ball mill for 8 hours, followed by filtration and drying, and the mixture was compressed under a pressure of 5 kg / cm². 2 The product was shaped and calcined for 8 hours at 1300°C. The calcined product was mechanically pulverized to obtain inorganic fine particles B-1 with a number-mean particle diameter of primary particles of 1000 nm. Production example of inorganic fine particles B-2 to B-7

[0236] Inorganic fine particles B-2 to B-7 were obtained in the same way as inorganic fine particles B-1, except that the pulverization conditions were adjusted to achieve a desired particle diameter. The respective number-mean particle diameters are shown in Table 6. [Table 6] Inorganic fine particles B No. Number mean particle diameter (nm) B-1 1000 B-2 600 B-3 1500 B-4 500 B-5 2000 B-6 400 B-7 2200 Production example of binder resin B-1 - Propylene oxide adduct of bisphenol A: 34.0 mol% (average number of added moles: 2.20) - Ethylene oxide adduct of bisphenol A: 19.5 mol% (average number of added moles: 2.20) - Isophthalic acid: 23.5 mol% - N-Dodecyl succinic acid: 13.5 mol% - Trimellitic acid: 9.5 mol%

[0237] To the above monomers, dibutyltin oxide was added in an amount of 0.03 parts based on 100 parts of the total acid component, and the reaction was carried out with stirring for 6 hours at 220°C under a nitrogen stream to obtain a binder resin B-1. The resin exhibited a softening point of 135°C and a Tg of 65°C. Example B-1

[0238] Production example of toner B-1 - Binder resin B-1: 100 parts - Fischer-Tropsch wax: 5 parts (melting point 105°C) - Magnetic iron oxide particles: 90 parts (number-average particle diameter: 0.20 µm, Hc (coercive force) = 10 kA / m, σs (saturation magnetization) = 83 Am 2 / kg, σr (residual magnetization) = 13 Am 2 / kg) - Aluminum compound of 3,5-di-tert-butyl salicylic acid: 1 part

[0239] The above materials were premixed using a Henschel mixer and melt-kneaded using a twin-screw kneading extruder.

[0240] The resulting kneaded product was cooled, coarsely pulverized using a hammer mill, and then pulverized using a jet mill. The resulting fine powder was classified using a multi-compartment unclassifier employing the Coanda effect, yielding negatively triboelectrically charged toner particles with a weight-averaged particle diameter (D4) of 6.8 µm. To 100 parts of the toner particles, 1.0 part strontium titanate A-1 (inorganic fine particles A), 3.0 parts inorganic fine particles B-1, and 1.0 part hydrophobic silicon dioxide fine powder (specific surface area, determined by nitrogen adsorption measured by the BET method, was 140 m²) were added. 2 / g) was added externally and mixed. This mixture was sieved using a 150 µm mesh sieve to obtain Toner B-1. The physical properties of Toner B-1 are shown in Table 7.

[0241] The evaluation was carried out by modifying the process speed of a commercially available digital copier (image RUNNER 4051, manufactured by Canon In.) to 252 mm / s. Evaluation of pod ghost image in low temperature and low humidity environments (LL)

[0242] The evaluation was carried out in the same way as the evaluation of the husk ghost image in the low temperature and low humidity environment in the first aspect. Evaluation of pod ghost images in high-temperature and high-humidity environments (HH)

[0243] The evaluation was carried out in the same way as the evaluation of the husk ghost image in the high-temperature and high-humidity environment in the first aspect. Evaluation of white stripes

[0244] White streaks were evaluated under a low-temperature and low-humidity environment (15°C, 10% RH) as follows. A total of 100,000 A4 sheets at a print density of 70% were continuously output. The presence or absence of white streaks in the image during paper feeding and the presence or absence of streaks due to aggregates on the core after the end of the continuous paper feeding were investigated and selected as follows. A: No white streaks were observed on the image and the sleeve due to paper feed resistance; B: White stripes could not be seen in the picture, but faint stripes could be seen on the sleeve; C: White stripes could not be seen in the image, but stripes were seen on the sleeve; D: White stripes appeared in the picture. Evaluation of cleaning defects

[0245] An evaluation of faulty cleaning was performed as follows. The contact pressure of the cleaning element against the photosensitive element was changed to 0.52 N (0.53 kgf), and 100,000 sheets of A4 text diagrams with a print percentage of 5% were printed under a low-temperature and low-humidity environment (15°C / 10% RH). The occurrence of vertical streaks caused by cleaning defects was investigated, and the contamination status of the loading element with toner or external additive was checked after completion of the permanent paper feed. The evaluation was based on the following criteria. A: No image defect caused by a cleaning defect was observed with the paper feed stability test, and the contamination state of the loading element after completion of the steady paper feed was equally satisfactory; B: Although no image defect caused by a cleaning defect was observed by the paper feed stability test, some contamination was observed in the loading element after the end of the stable paper feed; C: Although no image defect caused by a cleaning defect was observed during the paper feed stability test, contamination of the loading element was observed after the end of the stable paper feed; D: An image defect caused by a cleaning defect occurred during the paper feed resistance test.

[0246] The toner B-1 from example B-1 had a rating of A in each of the above evaluation points. Examples B-2 to B-16 Production examples of toners B-2 to B-16

[0247] Toners B-2 to B-16 were obtained in the same manner as in the production example for toner B-1, except that the weight-averaged particle diameter of the toner and the types and quantities of inorganic fine particles A and B were modified as shown in Table 7. Furthermore, these toners were evaluated in the same way as toner B-1. The evaluation results are shown in Table 8. [Table 7] Example No. Toner No. D4µm Inorganic fine particles A Inorganic fine particles B Mass ratio A / B Strontium titanate No. Quantity added (parts) Nr. Quantity added (parts) B-1 B-1 6,8 A-1 1,0 B-1 3,0 1,0 / 3,0 B-2 B-2 6,8 A-1 0,1 B-1 1,8 1,0 / 18,0 B-3 B-3 6,0 A-1 0,1 B-2 2,0 1,0 / 20,0 B-4 B-4 6,0 A-1 1,5 B-3 1,5 1,0 / 1,0 B-5 B-5 6,0 A-1 2,0 B-3 1,5 1,0 / 0,75 B-6 B-6 6,0 A-2 0,05 B-3 1,5 1,0 / 30,0 B-7 B-7 4,0 A-3 2,1 B-3 1,5 1,0 / 0,71 B-8 B-8 4,0 A-4 0,04 B-3 1,5 1,0 / 37,5 B-9 B-9 9,0 A-4 0,04 B-4 1,5 1,0 / 37,5 B-10 B-10 9,0 A-4 0,04 B-5 1,5 1,0 / 37,5 B-11 B-11 9,0 A-5 0,04 B-5 1,5 1,0 / 37,5 B-12 B-12 9,0 A-6 0,04 B-5 1,5 1,0 / 37,5 B-13 B-13 9,0 A-7 0,04 B-5 1,5 1,0 / 37,5 B-14 B-14 9,0 A-8 0,04 B-5 1,5 1,0 / 37,5 B-15 B-15 9,0 A-9 0,04 B-5 1,5 1,0 / 37,5 B-16 B-16 9,0 A-10 0,04 B-5 1,5 1,0 / 37,5 [Table 8] Example No. White stripes Cleaning defect Spooky image (low temperature and low humidity) Pod ghost image (high temperature and high humidity) classification classification classification Difference in density classification Difference in density B-1 A A A 0,01 A 0,01 B-2 A A A 0,01 A 0,01 B-3 A B A 0,01 A 0,01 B-4 A B A 0,01 A 0,01 B-5 B B A 0,01 A 0,01 B-6 B B A 0,01 A 0,01 B-7 B B B 0,02 A 0,01 B-8 B B B 0,02 A 0,01 B-9 B C B 0,02 A 0,01 B-10 B C B 0,02 A 0,01 B-11 B C B 0,03 B 0,02 B-12 B C C 0,04 B 0,02 B-13 B C C 0,04 B 0,02 B-14 B C C 0,04 C 0,04 B-15 C C C 0,04 C 0,04 B-16 C C C 0,04 C 0,04 Comparison examples B-1 to B-4; Production example of toners B-17 to B-20

[0248] Toners B-17 to B-20 were obtained in the same manner as in Example B-1, except that the particle diameter of the toner particles and the types and amounts of inorganic fine particles A and B were modified as shown in Table 9. Toners B-17 to B-20 were evaluated in the same manner as in Example B-1. The evaluation results are shown in Table 10. [Table 9] Comparison example no. Toner No. D4µm Inorganic fine particles A Inorganic fine particles B Mass ratio A / B Strontium titanate no. Quantity added (parts) Nr. Quantity added (parts) B-1 B-17 9,0 A-9 0,04 B-6 1,5 1,0 / 37,5 B-2 B-18 9,0 A-11 0,04 B-7 1,5 1,0 / 37,5 B-3 B-19 9,0 A-12 0,04 B-7 1,5 1,0 / 37,5 B-4 B-20 9,0 A-13 0,04 B-7 1,5 1,0 / 37,5 [Table 10] Comparison example no. White stripes Cleaning defect Spooky image (low temperature and low humidity) Pod ghost image (high temperature and high humidity) classification classification classification Difference in density classification Difference in density B-1 C D C 0,05 C 0,05 B-2 C D C 0,05 D 0,07 B-3 D D D 0,07 D 0,07 B-4 D D D 0,09 D 0,09

[0249] While the present invention has been described with reference to exemplary embodiments, it should be noted that the invention is not limited to the disclosed exemplary embodiments. The scope of protection of the following claims is to be interpreted in the broadest possible way, so that all such modifications and equivalent structures and functions are included.Toner comprising a toner particle and strontium titanate, wherein the strontium titanate has a specific number-mean particle diameter, the strontium titanate exhibits a maximum peak (a) at a diffraction angle (2θ) of 32.00° to 32.40° in CuKα characteristic X-ray diffraction, the half-width of the maximum peak (a) is 0.23° to 0.50°, an intensity (Ia) of the maximum peak (a) and a maximum peak intensity (Ix) in a range of a diffraction angle (2θ) of 24.00° to 28.00° satisfy a specific relationship, the content of strontium oxide and titanium oxide in the strontium titanate is at least 98.0 wt%, and a sum Et of a rotational torque and a vertical load in a powder flowability analysis of the toner is 100 mJ to 2000 mJ.

Claims

[1] Toner, which includes: a toner particle; inorganic fine particles A; and inorganic fine particles B, wherein a weight-averaged particle diameter D4 of the toner is at least 3.0 µm and not more than 10.0 µm; the inorganic fine particles A and the inorganic fine particles B are strontium titanate; a number-average particle diameter of primary particles of the inorganic fine particles A is at least 10 nm and not more than 95 nm; the inorganic fine particles A exhibit a maximum peak (a) at a diffraction angle 2θ of at least 32.00° and not more than 32.40° in CuKα characteristic X-ray diffraction; a half-width of the maximum peak (a) is at least 0.23° and not more than 0.50°; the inorganic fine particles A exhibit a water adsorption quantity of at least 1 mg / g and not more than 40 mg / g at a relative humidity of 80% in a water adsorption isotherm at 30°C; and a number-mean particle diameter of primary particles of the inorganic fine particles B is at least 500 nm and not more than 2000 nm. [2] Toner according to claim 1, wherein the content of the inorganic fine particles A is at least 0.05 parts by mass and not more than 2.0 parts by mass based on 100 parts by mass of the toner particle. [3] Toner according to claim 1 or 2, wherein the mass ratio A / B of the inorganic fine particles A and the inorganic fine particles B is 1.0 / 1.0 to 1.0 / 20.

0. [4] Toner according to any one of claims 1 to 3, wherein an intensity Ia of the maximum peak (a) in CuKα characteristic X-ray diffraction of the inorganic fine particles A and a maximum peak intensity Ix in a region of a diffraction angle 2θ of at least 24.00° and not more than 28.00° in CuKα characteristic X-ray diffraction of the inorganic fine particles A satisfy the following formula: Ix / Ia≤0.

010. [5] Toner according to any one of claims 1 to 4, wherein the inorganic fine particles A are surface-treated with a silane coupling agent.

Images