Magenta toner, toner container unit, image forming apparatus, and image forming method

Abstract

To provide a toner excellent in transferability and internal device contamination resistance without deteriorating cleanability.SOLUTION: A magenta toner contains at least a binder resin and a colorant. When the intensity of the Raman spectra of toner particles in a wave number λ which exhibits the maximum value in which the total intensity obtained by adding up the Raman spectra of toner particles obtained in a wave number region of 1200 cm-1 to 3250 cm-1 by the Raman spectroscopy of the magenta toner are added up is standardized to 1, and when the integrated intensity of the spectra of the toner particles obtained in a wave number region of 2750 cm-1 to 3250 cm-1 is In, the average value of the In is Iave, and a value calculated with the following (formula 1) is a CH ratio, the number ratio of toner particles having an absolute value of the CH ratio of 25.0% or more to the total toner particles is 1.0 number% or more and 25.0 number % or less. (Formula 1): CH ratio (%)=[(In-Iave) / Iave]×100.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a magenta toner, a developer, a toner container unit, an image forming apparatus, and an image forming method.

Background Art

[0002] In electrophotographic image formation, an electrostatic charge image (latent image) is formed on an electrostatic latent image carrier, charged toner is conveyed by a developer carrier, the latent image is developed to form a toner image, and then the toner image is transferred onto a recording medium such as paper and fixed by a method such as heating to obtain an output image. Further, a technique is known in which toner remaining on the electrostatic latent image carrier after transfer is recovered from the electrostatic latent image carrier by a cleaning member and discharged to a waste toner storage section.

[0003] In the above-described developing method, the toner particles supplied into the developing machine vary in particle size, shape, charging characteristics, etc., and it is very difficult to control all the particles ideally. When the mixing state of toner particles and a carrier is non-uniform and triboelectric charging cannot be obtained, or when the charging performance of toner particles is low, it cannot be controlled in the machine and scatters, causing contamination in the machine. Further, if the adhesion force between some toner and a carrier, a photoreceptor, or a transfer belt is too strong, sufficient transfer cannot be achieved and the toner consumption increases. Even a small variation in the characteristics of toner particles leads to an abnormality in the image system. Therefore, it is important to narrow the distribution of the characteristic values of each toner particle and improve the uniformity.

[0004] Patent Document 1 proposes narrowing the charge amount distribution and improving the transfer efficiency by using an external additive using a flame hydrolysis method. Patent Document 2 proposes improving the transfer rate by narrowing the shape distribution so that there are fewer overly deformed particles in addition to the selection of a specific release agent. In Patent Document 3, it is proposed that by selecting a specific resin, the abrasion resistance of the fixed image is improved, toner scattering is improved, and toner scattering is improved by narrowing the particle size distribution and spheroidizing the particles.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the toner of Patent Document 1, in the mixing step of mixing the toner base and the external additive, non-uniformity in the adhesion amount and embedding degree is inevitable, so there is a limit to improvement in terms of uniformity, and the improvement in transfer rate by narrowing the charge amount distribution has not reached a sufficient level. In the toner of Patent Document 2, although improvement in transfer rate is recognized by spheroidizing the shape, since the cleaning blade passes through, achieving both cleaning performance becomes an issue. Although the toner of Patent Document 3 has a certain effect on reducing scattering due to narrowing the particle size distribution, non-uniformity in particle size is inevitable during the granulation process, so it has not reached a sufficient level. Also, since the passage of the cleaning blade deteriorates due to spheroidization, achieving both improvement in toner scattering and cleaning performance is an issue.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a toner excellent in transferability and resistance to in-machine contamination without deteriorating cleaning performance.

Means for Solving the Problems

[0007] The present invention for solving the above problems is as described below. A magenta toner containing at least a binder resin and a colorant, wherein when the intensity of the Raman spectrum of each toner particle in the wavenumber region of 1200 cm -1 ~3250 cm -1 obtained by adding up the Raman spectra of each toner particle is normalized to 1 at the wavenumber λ showing the maximum value, the intensity of the Raman spectrum of each toner particle at 2750 cm -1 ~3250 cm -1The integrated intensity of the spectrum of each toner particle obtained in the wavenumber region is I n Let it be, and the average value of the above I n is I ave When the value calculated by the following (Equation 1) is defined as the CH rate, the number ratio of toner particles with an absolute value of the CH rate of 25.0% or more to all toner particles is 1.0 number % or more and 25.0 number % or less, a magenta toner. CH rate (%) = [(I n - I ave ) / I ave × 100 ··· (Equation 1)

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a toner excellent in transferability and resistance to in-machine contamination without deteriorating the cleaning property.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of a magenta toner (hereinafter also simply referred to as "toner"), a developer, a toner container unit, an image forming apparatus, and an image forming method according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be changed within the scope that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc., and as long as the functions and effects of the present invention are exhibited in any aspect, it is included in the scope of the present invention.

[0011] (Toner) The present invention is a magenta toner containing a binder resin and a colorant, and the number ratio of toner particles having an absolute value of the "CH rate" described later of 25.0% or more to all toner particles is 1.0% by number or more and 25.0% by number or less. Details will be described below.

[0012] <Overview of CH rate> The CH rate is a term taking the initials of Content Heterogeneity, and is an index defined to evaluate the non-uniformity of the raw material content in the toner. It compares with the raw material content ratio at the time of toner creation and evaluates how much the raw material content ratio of each toner particle deviates. Of course, it is preferable that the raw material content ratio of each toner particle does not deviate from the raw material content ratio at the time of toner creation.

[0013] <Calculation method of CH rate> The CH rate is calculated from the Raman spectrum of the toner. The "CH rate" in the present invention means that in the range of 1200 cm -1 ~3250 cm -1 of the Raman spectroscopy of the toner, the wave number at which the total intensity obtained by adding the Raman spectra of the toner particles shows the maximum value is defined as λ, and when the intensity of the Raman spectrum at the wave number λ of each toner particle is normalized to 1, in the wave number region of 2750 cm -1 ~3250 cm -1 the integrated intensity of the spectrum of each toner particle obtained is I n and the average value of the I n is Iave When it is [a certain value], it is the value represented by the following (Formula 1). CH rate (%) = [(I n - I ave ) / I ave × 100 ··· (Formula 1) The Raman spectrum is measured using a Raman microscope. The device to be used is not particularly limited. For example, it is measured using "XploRA PLUS" (manufactured by Horiba, Ltd.). The Raman spectrum is measured for each toner particle, and after obtaining the spectra of 500 to 600 particles, the CH rate is calculated using the above (Formula 1).

[0014] <Measurement conditions of Raman spectrum> In the present invention, the Raman spectrum is measured under the following measurement conditions. (1) Selection of excitation laser For the measurement of the Raman spectrum, a laser with an excitation wavelength of 785 nm is used. The measurement is performed by irradiating each toner particle with the laser, and the laser intensity is adjusted to an intensity at which the toner does not melt. (2) Number of particles to be measured The spectral shape varies slightly for each toner particle. To evaluate the variation, 500 to 600 toner particles are measured. By measuring 500 to 600 toner particles, the measurement variation converges, and it becomes possible to compare different toners. (3) Wavenumber region to be measured The analysis is performed using a wavenumber region of 1200 cm -1 ~3250 cm -1 . Therefore, it is necessary to measure a wavenumber region including this range. (4) Focus adjustment conditions Adjustment is performed so that the focus is on the outermost surface of the toner particle. (5) Other setting items As other measurement conditions related to the resolution of the Raman spectrum, the measurement is performed with an objective lens of 50 times magnification, and the measurement is performed with a resolution setting such that the plot interval in the wavenumber direction of the Raman spectrum is about 1 cm -1 ~2 cm -1 .

[0015] <Method for Preparing Sample> In order to measure toner particles one by one, a sample is prepared by dispersing toner on a quartz substrate.

[0016] <Correction of Raman Spectrum> Since the Raman spectrum includes the influence of fluorescence and noise, it is desirable to perform baseline correction on the spectral data. The method of baseline correction is not particularly limited, and an example of the correction method is shown below. The baseline correction of the spectrum is performed using, for example, the software "Labspec6.0" (manufactured by Horiba, Ltd.). (1) Extract the wavenumber region of the measured Raman spectrum from 1200 cm -1 to 3800 cm -1 . (2) Execute baseline correction on the above (1) with "Degree: 5", "Maximum Points: 4", and "Noise Points: 0". (3) Extract the wavenumber region of the spectrum of the above (2) from 1200 cm -1 to 3250 cm -1 again.

[0017] <Normalization of Raman Spectrum> Since the intensity of the Raman spectrum varies depending on the size and shape of the measurement object, the type of raw material, etc., it is not possible to simply compare the Raman spectrum intensities of different toners. Therefore, normalization processing is performed on the Raman spectrum so that different toners can be compared. The normalization processing is performed using data editing software (for example, Excel, etc.) on the spectrum whose baseline has been corrected.

[0018] Normalization is performed by the following method. (1) As shown in Fig. 1, calculate the total spectrum obtained by adding all Raman spectra, and obtain the wavenumber λ at which the total spectrum shows the maximum intensity. (2) As shown in FIG. 2, for the Raman spectrum of the n-th particle, a correction coefficient X(n) is obtained such that the intensity at the wave number λ becomes 1, and the spectrum intensity is normalized by multiplying the correction coefficient X(n) across the entire wave number region. Hereinafter, the spectrum after the normalization is referred to as the normalized spectrum. This is performed for the Raman spectra of all the particles measured.

[0019] <Excluding noise data> In the measurement of the Raman spectrum, there may be cases where data such as dust is acquired as noise, and if these are added to the CH rate calculation, correct evaluation may not be possible. Therefore, the noise data is excluded as follows. For the normalized spectrum of the n-th particle in (2) above, the area S(n) of the spectrum is calculated. This is performed for all the particles measured. The standard deviation σ(S) of S(n) for all the particles is calculated, and particles (n) that do not satisfy S(n) - 2×σ(S) ≤ S(n) ≤ S(n) + 2×σ(S) are treated as error data and excluded from the CH rate calculation target.

[0020] <Calculation of CH rate> FIG. 3 is a diagram showing the region of 2750 cm -1 ~3250 cm -1 in FIG. 2. An average spectrum is obtained using the particles (n) that were not excluded by the noise data exclusion process. FIG. 4 shows the average spectrum obtained in FIG. 3 and the spectra of the particles (n) arranged in the figure. The integrated intensity I -1 ~3250 cm -1 at 2750 cm of the particle (n) is calculated, and the average value is calculated using the I n of all the particles, which is designated as I n ave ave ave The difference in the integrated intensity between the particle (n) and the average spectrum at 2750 cm -1 ~3250 cm -1 is I n -I aveIt becomes. As the calculation of the change rate with respect to the average, the CH rate is calculated using the following (Equation 1). CH rate (%) = [(I n - I ave ) / I ave × 100 ··· (Equation 1) I n : The integrated intensity of the Raman spectrum of the n-th particle in the range of 2750 cm -1 ~3250 cm -1 I ave : The average value of I n for all the particles

[0021] Since the intensity of the Raman spectrum varies depending on the type of raw material used, the CH rate is not calculated by the difference between I n and I ave , but is calculated as a rate of change as in (Equation 1) using the same concept as the coefficient of variation (CV). Generally, by performing the analysis using the range of 2750 cm -1 ~3250 cm -1 where the spectrum of the colorant hardly appears, the variation in the content of raw materials other than the colorant can be accurately evaluated.

[0022] As a result of intensive studies on the problem of achieving both transferability, resistance to in-machine contamination, and cleanability, the inventors have found that in the CH rate indicating the non-uniformity of the resin component content in the toner, it is important that the proportion of particles with an absolute value of the CH rate of 25.0% or more is 1.0 number % or more and 25.0 number % or less. If the proportion of particles with an absolute value of the CH rate of 25.0% or more exceeds 25.0 number %, the effect of suppressing in-machine contamination due to toner scattering and the effect of improving transferability become insufficient, which is not preferable. On the other hand, when the absolute value of the CH rate is less than 1.0 number %, although the background contamination toner will also be greatly reduced, the dam in the cleaning blade part formed by the conventional background contamination toner may become insufficient, and there is a possibility of poor cleaning.

[0023] ​In addition, since the number of particles with an absolute value of the CH rate of 25.0% or more is 5.0% by number or more and 20.0% by number or less, a further effect of suppressing in-machine contamination, an effect of improving transferability, and good cleanability can be obtained.

[0024] The ratio of toner particles with an absolute value of the CH rate of 50.0% or more is preferably 3.0% by number or less, and more preferably 2.0% by number or less. The threshold value of the absolute value of the CH rate of 50.0% is approximately outside the tail of the distribution, and toner particles with an absolute value of the CH rate of 50.0% or more are toner particles with extremely different compositions deviating from the normal distribution. Such toner particles can also cause poor transfer, and are particularly likely to scatter inside the machine. By reducing the ratio of toner particles with an absolute value of the CH rate of 50.0% or more, it is possible to improve the resistance to in-machine contamination.

[0025] The median value of the CH rate is preferably -3.0% or more. When the median value of the CH rate is -3.0% or more, toner scattering due to carrier deterioration does not occur and the resistance to in-machine contamination does not deteriorate. Since the CH rate evaluates the deviation from the average spectrum, the sum of the CH rates of all toner particles becomes zero. However, when there is a bias in the component distribution, especially when there are some particles with extremely different compositions, the median value of the CH rate will not be zero.

[0026] When the median value of the CH rate is negative, it means that there are toner particles with extremely high CH rates, that is, a large amount of resin components. Conversely, when the median value of the CH rate is positive, it means that there are toner particles with extremely low CH rates, that is, a small amount of resin components, for example, toner particles with an extremely large amount of colorants.

[0027] For toner particles with a high CH rate and a large amount of resin components, there is a high possibility that an excessive amount of release agent is contained. Toner particles containing a large amount of release agent are likely to be spent on the carrier, resulting in a decrease in charging ability due to carrier contamination. Therefore, the lower the median value of the CH rate, the more toners there are with a high CH rate and a high tendency to cause carrier contamination. It is preferable to prevent the median value of the CH rate from becoming a low value.

[0028] The method for manufacturing the toner of the present invention is not particularly limited. In the kneading and pulverizing method, it is desirable to pulverize in a state where the raw materials are more uniformly finely dispersed in the binder resin, such as by pre-finely dispersing the raw materials, increasing the intensity of the kneading step, and preventing re-aggregation by temperature control.

[0029] As an example of the chemical method, the dissolution-suspension method will be described in detail. After dissolving a toner composition containing at least a binder resin, a colorant, and a release agent in an organic solvent, the material is refined by a shearing force or a collision force. At this time, by using the shearing force and the collision force in combination, it is possible to efficiently reduce the toner with a non-uniform composition having an absolute value of the CH rate of 25.0% or more.

[0030] The dispersion method is not particularly limited, but for dispersion by shearing, a method of pulverizing the material with a high shearing force generated in a narrow gap between a rotor and a stator is preferably used. For dispersion by collision, a method of filling beads such as zirconia in a vessel and rotating it to pulverize the material by collision between the beads or between the beads and the vessel is preferably used.

[0031] Pulverization by collision is particularly effective for large materials exceeding 1 μm, while pulverization by shearing is effective for further refining submicron-order materials. Since the two methods have different main pulverization target regions, it is possible to improve the uniformity of the material by using them in combination. Therefore, it is particularly preferable to use the two methods in combination. The order of dispersion by shearing and dispersion by collision is not limited.

[0032] In order to efficiently refine the material, it is preferable that the peripheral speed of the rotor exceeds 12 m / s in the case of microdispersion by shear. Further, in the case of pulverization by collision, it is preferable that the disk peripheral speed is 6 m / s or more, and more preferably 10 m / s to 12 m / s. In the case of pulverization by collision, when the disk peripheral speed is less than 6 m / s, sufficient pulverization energy by collision cannot be obtained, and uneven distribution of the beads occurs, resulting in insufficient dispersion. Conversely, if the disk peripheral speed is increased too much, there is a concern that the material will be overly dispersed, leading to a deterioration in cleaning performance due to a decrease in ground soil toner. There are also risks such as an increase in liquid temperature and re-aggregation due to over-dispersion.

[0033] The media diameter is preferably 0.5 mm or less, and more preferably 0.4 mm to 0.3 mm or less. The smaller the beads, the larger the total surface area of the beads, so the dispersion opportunity by collision increases and the dispersion efficiency improves. If it is too small, it is necessary to narrow the mesh opening of the screen for separating the beads and the process liquid, so there is a risk that the flow rate cannot be achieved, the liquid temperature rises, and re-aggregation occurs.

[0034] Furthermore, in order to reduce toner particles with a non-uniform composition such that the absolute value of the CH rate exceeds 25.0%, it is also effective to add and disperse an inorganic substance harder than organic substances such as a colorant and a release agent in the dispersion liquid. The inorganic substance is not particularly limited, but as an example, the case of adding montmorillonite, an organically modified layered inorganic mineral, will be described below.

[0035] After dissolving a toner composition containing an organically modified layered inorganic mineral in addition to at least a binder resin, a colorant, and a release agent in an organic solvent, a media type disperser is used to refine the material by collision force. When the composition contains an organically modified layered inorganic mineral, compared with the case where it does not contain an organically modified layered inorganic mineral, it is possible to more efficiently microdisperse the material and reduce toner particles with a non-uniform composition. This is because collision opportunities occur not only between the beads, between the beads and the vessel, but also between the beads and the inorganic substance, and between the vessel and the inorganic substance, so it is possible to effectively disperse the organic substance with low hardness. In rotor-stator type shear dispersion, even if an inorganic substance is added, the pulverization efficiency does not increase, and it is important to utilize the inorganic substance as a grinding medium.

[0036] The addition amount of the inorganic substance is preferably 0.2 mass% to 2.0 mass%, more preferably 0.7 mass% to 1.5 mass% based on the total solid content. When the addition amount is 0.2 mass% to 2.0 mass%, the function as a grinding medium is sufficiently exhibited, and the uniformity of the CH rate is improved.

[0037] Also, regarding the shape, size, etc. of the toner, there are no particular restrictions, and it can be appropriately selected according to the purpose, but it preferably has the following such as average circularity, volume average particle size, ratio of volume average particle size to number average particle size (volume average particle size / number average particle size), etc.

[0038] The average circularity is the average value of the circularity which is the value obtained by dividing the perimeter of a circle equivalent to the shape and projected area of the toner by the perimeter of the projected image of the toner. For example, 0.950 to 0.980 is preferable, and 0.960 to 0.975 is more preferable. In addition, it is preferable that the number of particles with a circularity of less than 0.950 is 15.0% or less.

[0039] When the average circularity is 0.950 or more, satisfactory transferability and a high-quality image without scattering can be obtained. Also, when it is 0.980 or less, in an image forming system employing blade cleaning or the like, there is no occurrence of cleaning failure on the photoreceptor and transfer belt, etc., and in the case of forming an image with a high image area ratio such as a photographic image, toner that forms an untransferred image due to paper feeding failure or the like accumulates as residual toner on the photoreceptor, and there is no occurrence of background staining of the image, and also, since it does not contaminate a charging roller or the like that contact-charges the photoreceptor, the original charging ability can be exhibited.

[0040] The average circularity can be measured using a flow-type particle image analyzer ("FPIA-2100", manufactured by Sysmex Corporation) and analyzed using analysis software (FPIA-2100 Data Processing Program for FPIA version00-10).

[0041] For a specific example, 0.1 to 0.5 mL of an aqueous solution of a 10 mass% surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 mL glass beaker, 0.1 to 0.5 g of each toner is added, and the mixture is stirred with a microspatula. Then, 80 mL of ion-exchanged water is added. The resulting dispersion is subjected to dispersion treatment with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.) for 3 minutes. The shape and distribution of the toner are measured with the FPIA-2100 until a concentration of 5,000 to 15,000 particles / μL is obtained for the dispersion.

[0042] In terms of the measurement reproducibility of the average circularity, it is important that the concentration of the dispersion is 5,000 to 15,000 particles / μL in this measurement method. In order to obtain the concentration of the dispersion, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant added and the amount of toner. The amount of surfactant required varies depending on the hydrophobicity of the toner, similar to the measurement of the toner particle size described above. If too much is added, noise due to bubbles will occur, and if too little is added, the toner cannot be sufficiently wetted, resulting in insufficient dispersion. Also, the amount of toner added varies depending on the particle size, and it is necessary to add less for small particle sizes and more for large particle sizes. When the toner particle size is 3 μm to 10 μm, the dispersion concentration can be adjusted to 5,000 particles / μL to 15,000 particles / μL by adding 0.1 g to 0.5 g of toner.

[0043] There is no particular limitation on the volume average particle size of the toner, and it can be appropriately selected according to the purpose. It is possible, for example, 3 μm to 10 μm is preferable, and 4 μm to 7 μm is more preferable. If the volume average particle diameter is less than 3 μm, in a two-component developer, toner may fuse to the surface of the carrier during long-term agitation in the developing device, which may reduce the charging ability of the carrier. If it exceeds 10 μm, it becomes difficult to obtain a high-resolution and high-quality image, and when the balance of toner in the developer is maintained, the variation in the particle diameter of the toner may increase.

[0044] As the ratio (volume average particle diameter / number average particle diameter) between the volume average particle diameter and the number average particle diameter in the toner, 1.00 to 1.25 is preferable, and 1.00 to 1.15 is more preferable. The volume average particle diameter and the ratio (volume average particle diameter / number average particle diameter) between the volume average particle diameter and the number average particle diameter can be measured using a particle size analyzer (“Multi-Sizer III”, manufactured by Beckman Coulter, Inc.) with an aperture diameter of 100 μm and analyzed using analysis software (Beckman Coulter Mutlisizer 3 Version 3.51).

[0045] Specifically, 0.5 mL of an aqueous solution of a 10 mass% surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 mL glass beaker, 0.5 g of each toner is added and stirred with a microspatula, and then 80 mL of ion-exchanged water is added. The obtained dispersion is dispersed for 10 minutes using an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion can be measured using the Multi-Sizer III with Isoton III (manufactured by Beckman Coulter, Inc.) as the measurement solution.

[0046] The measurement is performed by dropping the toner sample dispersion so that the concentration indicated by the device becomes 8 ± 2%. In terms of the measurement reproducibility of the particle diameter, it is important to set the concentration to 8 ± 2%. Within this concentration range, no error will occur in the particle diameter.

[0047] <Toner raw material> The toner of the present invention can contain at least a binder resin in a toner base, and can contain other components such as a release agent as needed, and an external additive can be added as needed.

[0048] <<Binder resin>> There is no particular limitation on the binder resin, and it can be appropriately selected according to the purpose. For example, polyester resin, silicone resin, styrene-acrylic resin, styrene resin, acrylic resin, epoxy resin, diene resin, phenol resin, terpene resin, coumarin resin, amide-imide resin, butyral resin, urethane resin, ethylene vinyl acetate resin, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, polyester resin and a resin obtained by combining a polyester resin and the above other binder resins are preferable in terms of excellent low-temperature fixability and sufficient flexibility even when the molecular weight is reduced.

[0049] - Polyester resin - There is no particular limitation on the polyester resin, and it can be appropriately selected according to the purpose. However, an unmodified polyester resin and a modified polyester resin are preferable. These may be used alone or in combination of two or more.

[0050] -- Unmodified polyester resin -- There is no particular limitation on the unmodified polyester resin, and it can be appropriately selected according to the purpose. For example, a resin obtained by esterifying a polyol represented by the following general formula (1) and a polycarboxylic acid represented by the following general formula (2), a crystalline polyester resin, etc. can be mentioned.

[0051]

Chemical formula

[0052] However, in the general formula (1), A represents an alkyl group having 1 to 20 carbon atoms, an alkylene group, an aromatic group which may have a substituent, or a heteroaromatic group, and m represents an integer of 2 to 4. In the general formula (2), B represents an alkyl group having 1 to 20 carbon atoms, an alkylene group, an aromatic group or a heteroaromatic group which may have a substituent, and n represents an integer of 2 to 4.

[0053] The polyol represented by the general formula (1) is not particularly limited and can be appropriately selected according to the purpose. For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like can be mentioned. These may be used alone or in combination of two or more.

[0054] The polycarboxylic acid represented by the general formula (2) is not particularly limited and can be appropriately selected according to the purpose. For example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isooctyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, Empol trimer acid, etc., cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid, butanetetracarboxylic acid, diphenylsulfonetetracarboxylic acid, ethylene glycol bis(trimeric acid), and the like. These may be used alone or in combination of two or more.

[0055] --Modified polyester resin-- The modified polyester resin is not particularly limited and can be appropriately selected according to the purpose. For example, resins obtained by subjecting an active hydrogen group-containing compound and a polyester capable of reacting with the active hydrogen group-containing compound (hereinafter sometimes referred to as "polyester prepolymer") to an extension reaction and / or a crosslinking reaction can be mentioned. The extension reaction and / or the crosslinking reaction may be stopped with a reaction terminator (such as a monoamine blocked with diethylamine, dibutylamine, butylamine, laurylamine, a ketimine compound, etc.) as necessary.

[0056] ---Active hydrogen group-containing compound--- In the aqueous phase, the active hydrogen group-containing compound acts as an extender, a crosslinking agent, etc. when the polyester prepolymer undergoes an elongation reaction, a crosslinking reaction, etc.

[0057] The active hydrogen group-containing compound is not particularly limited as long as it has an active hydrogen group, and can be appropriately selected according to the purpose. Among them, when the polyester prepolymer is an isocyanate group-containing polyester prepolymer described later, amines are preferable in that the molecular weight can be increased.

[0058] The active hydrogen group is not particularly limited and can be appropriately selected according to the purpose. For example, a hydroxyl group (alcoholic hydroxyl group or phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, etc. are mentioned. These may be contained alone or in combination of two or more.

[0059] The amines as the active hydrogen group-containing compound are not particularly limited and can be appropriately selected according to the purpose. For example, diamines, polyamines having a valence of 3 or more, amino alcohols, amino mercaptans, amino acids, those in which the amino groups of these amines are blocked, etc. are mentioned.

[0060] Examples of the diamine include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylmethane, etc.); alicyclic diamines (4,4'-diamino-3,3'-dimethyl dicyclohexylmethane, diamine cyclohexane, isophoronediamine, etc.); aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.). Examples of the polyamine having a valence of 3 or more include diethylenetriamine, triethylenetetramine, etc. Examples of the amino alcohol include ethanolamine, hydroxyethylaniline, etc. Examples of the amino mercaptan include aminoethyl mercaptan, aminopropyl mercaptan, etc.

[0061] Examples of the amino acid include aminopropionic acid and amino caproic acid. Examples of those obtained by blocking the amino groups of these amines include ketimine compounds and oxazolidone compounds obtained from any of these amines (diamines, polyamines with a valence of 3 or more, amino alcohols, amino mercaptans, amino acids, etc.) and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.).

[0062] These may be used alone or in combination of two or more. Among these, diamines and mixtures of diamines and a small amount of polyamines with a valence of 3 or more are particularly preferred for the amines.

[0063] ---Polymer capable of reacting with active hydrogen group-containing compound--- The polymer capable of reacting with the active hydrogen group-containing compound is not particularly limited as long as it is a polymer having at least a group capable of reacting with the active hydrogen group-containing compound, and can be appropriately selected according to the purpose. Among them, a urea bond-forming group-containing polyester resin (RMPE) is preferable, and an isocyanate group-containing polyester prepolymer is more preferable in terms of excellent high fluidity and transparency during melting, easy adjustment of the molecular weight of the polymer component, excellent oil-free low-temperature fixability and releasability in dry toner.

[0064] The isocyanate group-containing polyester prepolymer is not particularly limited and can be appropriately selected according to the purpose. For example, polycondensates of polyols and polycarboxylic acids, those obtained by reacting an active hydrogen group-containing polyester resin with a polyisocyanate, etc. may be mentioned.

[0065] The polyol is not particularly limited and can be appropriately selected according to the purpose. For example, alkylene glycols (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.), alkylene ether glycols (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.), alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.), bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.), polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.), phenols with a valence of 3 or more (phenol novolac, cresol novolac, etc.), polyols with a valence of 3 or more such as alkylene oxide adducts of polyphenols with a valence of 3 or more; mixtures of diols and polyols with a valence of 3 or more; and the like.

[0066] These may be used alone or in combination of two or more. Among these, the polyol is preferably the diol alone or a mixture of the diol and a small amount of the polyol with a valence of 3 or more.

[0067] The diol preferably contains, as the main component, an alkylene glycol having 2 to 12 carbon atoms or an alkylene oxide adduct of bisphenols (bisphenol A ethylene oxide 2-mol adduct, bisphenol A ethylene oxide 3-mol adduct). Further, for the purpose of adjusting the molecular weight and the mobility of the molecular weight, an alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, etc.) may be used.

[0068] The content of the polyol in the isocyanate group-containing polyester prepolymer is not particularly limited and can be appropriately selected according to the purpose. For example, 0.5% by mass to 40% by mass is preferable, 1% by mass to 30% by mass is more preferable, and 2% by mass to 20% by mass is particularly preferable. When the content is less than 0.5% by mass, the hot offset resistance deteriorates, and it may be difficult to achieve both the storage stability and the low-temperature fixability of the toner. When it exceeds 40% by mass, the low-temperature fixability may deteriorate.

[0069] The polycarboxylic acid is not particularly limited and can be appropriately selected according to the purpose. For example, alkylene dicarboxylic acids (such as succinic acid, adipic acid, sebacic acid); alkenylene dicarboxylic acids (such as maleic acid, fumaric acid); aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid); polycarboxylic acids with three or more valences (such as aromatic polycarboxylic acids with 9 to 20 carbon atoms such as trimellitic acid, pyromellitic acid, etc.) and the like can be mentioned. These may be used alone or in combination of two or more.

[0070] Among these, the polycarboxylic acid is preferably an alkenylene dicarboxylic acid having 4 to 20 carbon atoms or an aromatic dicarboxylic acid having 8 to 20 carbon atoms. Instead of the polycarboxylic acid, an anhydride of a polycarboxylic acid, a lower alkyl ester (such as methyl ester, ethyl ester, isopropyl ester, etc.) and the like may be used.

[0071] The mixing ratio of the polyol and the polycarboxylic acid is not particularly limited and can be appropriately selected according to the purpose. The equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the polyol and the carboxyl group [COOH] of the polycarboxylic acid is preferably 2 / 1 to 1 / 1, more preferably 1.5 / 1 to 1 / 1, and particularly preferably 1.3 / 1 to 1.02 / 1.

[0072] The polyisocyanate is not particularly limited and can be appropriately selected according to the purpose. For example, aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, tetramethylhexane diisocyanate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, diphenylene-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, etc.); araliphatic diisocyanates (α,α,α',α'-tetramethylxylylene diisocyanate, etc.); isocyanurates (tris-isocyanatoalkyl-isocyanurate, triisocyanatocycloalkyl-isocyanurate, etc.); phenol derivatives thereof; those blocked with oxime, caprolactam, etc. These may be used alone or in combination of two or more.

[0073] The mixing ratio of the polyisocyanate and the active hydrogen group-containing polyester resin (hydroxyl group-containing polyester resin) is not particularly limited and can be appropriately selected according to the purpose. The equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] of the polyisocyanate and the hydroxyl group [OH] of the hydroxyl group-containing polyester resin is preferably 5 / 1 to 1 / 1, more preferably 4 / 1 to 1.2 / 1, and particularly preferably 3 / 1 to 1.5 / 1. When the equivalent ratio [NCO] / [OH] is less than 1 / 1, the offset resistance may deteriorate, and when it exceeds 5 / 1, the low-temperature fixing property may deteriorate.

[0074] The content of the polyisocyanate in the isocyanate group-containing polyester prepolymer is not particularly limited and can be appropriately selected according to the purpose. 0.5% by mass to 40% by mass is preferable, 1% by mass to 30% by mass is more preferable, and 2% by mass to 20% by mass is particularly preferable. When the content is less than 0.5% by mass, the hot offset resistance deteriorates, and it may be difficult to achieve both storage stability and low-temperature fixing property. When it exceeds 40% by mass, the low-temperature fixing property may deteriorate.

[0075] The average number of isocyanate groups contained per molecule of the isocyanate group-containing polyester prepolymer is preferably 1 or more, more preferably 1.2 to 5, and still more preferably 1.5 to 4. When the average number is less than 1, the molecular weight of the polyester resin (RMPE) modified with the urea bond-forming group may be low, and the hot offset resistance may deteriorate.

[0076] The mixing ratio of the isocyanate group-containing polyester prepolymer and the amines is not particularly limited and can be appropriately selected according to the purpose. The mixing equivalent ratio [NCO] / [NHx] of the isocyanate group [NCO] in the isocyanate group-containing polyester prepolymer and the amino group [NHx] in the amines is preferably 1 / 3 to 3 / 1, more preferably 1 / 2 to 2 / 1, and particularly preferably 1 / 1.5 to 1.5 / 1. When the mixing equivalent ratio ([NCO] / [NHx]) is less than 1 / 3, the low-temperature fixing property may decrease. When it exceeds 3 / 1, the molecular weight of the urea-modified polyester resin may be low, and the hot offset resistance may deteriorate.

[0077] ---Synthesis method of polymer capable of reacting with active hydrogen group-containing compound--- As a method for synthesizing a polymer capable of reacting with the active hydrogen group-containing compound, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, in the case of the isocyanate group-containing polyester prepolymer, the polyol and the polycarboxylic acid are heated to 150°C to 280°C in the presence of a known esterification catalyst (such as titanium tetrabutoxide, dibutyltin oxide, etc.), and generated while appropriately reducing the pressure as necessary, and water is distilled off to obtain a hydroxyl group-containing polyester. Then, a method of synthesizing by reacting the polyisocyanate with the hydroxyl group-containing polyester at 40°C to 140°C can be mentioned.

[0078] There is no particular limitation on the weight average molecular weight (Mw) of the polymer capable of reacting with the active hydrogen group-containing compound, and it can be appropriately selected according to the purpose. In terms of the molecular weight distribution by GPC (gel permeation chromatography) of the THF-soluble component, 3,000 to 40,000 is preferable, and 4,000 to 30,000 is more preferable. When the weight average molecular weight (Mw) is less than 3,000, the storage stability may deteriorate, and when it exceeds 40,000, the low-temperature fixing property may deteriorate.

[0079] The measurement of the weight average molecular weight (Mw) can be carried out, for example, as follows. First, the column is stabilized in a heat chamber at 40°C, and tetrahydrofuran (THF) is flowed as a column solvent at a flow rate of 1 mL per minute at this temperature. A 50 μL to 200 μL of a tetrahydrofuran sample solution of a resin with the sample concentration adjusted to 0.05 to 0.6 mass% is injected for measurement. When measuring the molecular weight of the sample, it is calculated from the relationship between the logarithmic value of the calibration curve created by several monodisperse polystyrene standard samples and the count number of the molecular weight distribution of the sample.

[0080] As the standard polystyrene sample for preparing the calibration curve, those with molecular weights of 6×10, 2.1×10 2 , 4×10 2 , 1.75×10 4 , 1.1×10 5 , 3.9×105 , 8.6×10 5 , 2×10 6 , and 4.48×10 6 It is preferable to use at least about 10 standard polystyrene samples. As the detector, an RI (refractive index) detector can be used.

[0081] [[Release agent]] The release agent is not particularly limited and can be appropriately selected according to the purpose. For example, plant waxes (such as carnauba wax, cotton wax, wood wax, rice wax, etc.), animal waxes (such as beeswax, lanolin, etc.), mineral waxes (such as ozokerite, ceresin, etc.), petroleum waxes (such as paraffin, microcrystalline wax, petrolatum, etc.) and other waxes; those other than natural waxes such as synthetic hydrocarbon waxes (such as Fischer-Tropsch wax, polyethylene wax, etc.), synthetic waxes (such as esters, ketones, ethers, etc.); fatty acid amides such as 1,2-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbons; crystalline polymers with long-chain alkyl groups in the side chain such as homopolymers or copolymers of polyacrylates (such as poly(n-stearyl methacrylate), poly(n-lauryl methacrylate), etc.) (such as n-stearyl acrylate-ethyl methacrylate copolymer, etc.).

[0082] Among these, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, monoester wax, and rice wax are preferable in that they generate less unnecessary volatile organic compounds during fixing.

[0083] As the release agent, commercially available products can be used. Examples of the microcrystalline wax include "HI-MIC-1045", "HI-MIC-1070", "HI-MIC-1080", "HI-MIC-1090" manufactured by Nippon Seiro Co., Ltd., "Be Square 180 White", "Be Square 195" manufactured by Toyo Adres Co., Ltd., "BARECO C-1035" manufactured by WAXPetrolife Co., "CRAYVALLAC WN-1442" manufactured by Cray Vally Co., and the like.

[0084] The melting point of the release agent is not particularly limited and can be appropriately selected according to the purpose, but 60°C to 100°C is preferable, and 65°C to 90°C is more preferable. When the melting point is 60°C or higher, even during high-temperature storage at about 30 to 50°C, the bleeding of the release agent from the toner matrix can be suppressed, and the heat-resistant storage property can be maintained well. When it is 100°C or lower, it is preferable because cold offset is less likely to occur during fixing at low temperatures.

[0085] The melting point is measured by DSC. For example, using TA-60WS and DSC-60 manufactured by Shimadzu Corporation, it can be measured under the following measurement conditions. (Measurement conditions) Sample container: Aluminum sample pan with lid Sample amount: 5 mg Reference: Aluminum sample pan with 10 mg of alumina Atmosphere: Nitrogen (flow rate 50 mL / min) Temperature conditions 1st heating: Start temperature: 20°C, Heating rate: 10°C / min, End temperature: 150°C, Holding time: None 1st cooling: Cooling rate: 10°C / min, End temperature: 20°C, Holding time: None 2nd heating: Heating rate: 10°C / min, End temperature: 150°C The measurement results are analyzed using data analysis software (TA-60, version 1.52) manufactured by Shimadzu Corporation. The melting point uses the temperature at the peak top of the endothermic peak measured in the 2nd heating.

[0086] The release agent preferably exists in a dispersed state in the toner base particles. For this purpose, it is preferable that the release agent and the binder resin are incompatible. There is no particular limitation on the method by which the release agent is finely dispersed in the toner base particles, and it can be appropriately selected according to the purpose. Examples thereof include a method of dispersing by applying a shearing force during kneading in toner production.

[0087] The dispersion state of the release agent can be confirmed by observing a thin film section of the toner particles with a transmission electron microscope (TEM). The dispersion diameter of the release agent is preferably small, but if it is too small, bleeding during fixing may be insufficient. Therefore, if the release agent can be confirmed at a magnification of 10,000 times, it means that the release agent exists in a dispersed state. If the release agent cannot be confirmed at a magnification of 10,000 times, even if it was finely dispersed, bleeding during fixing will be insufficient.

[0088] The content of the release agent in the toner is not particularly limited and can be appropriately selected according to the purpose, but is preferably 3% by mass to 15% by mass, and more preferably 5% by mass to 10% by mass. When the content of the release agent in the toner is 3% by mass or more (especially 5% by mass or more), the hot offset resistance does not deteriorate, and when it is 15% by mass or less (especially 10% by mass or less), the bleeding amount of the release agent during fixing does not become excessive and the heat-resistant storage stability does not deteriorate, which is preferable.

[0089] <<Other components>> -Colorant- There is no particular limitation on the colorant used in the toner, and it can be appropriately selected from known colorants according to the purpose.

[0090] The color of the toner is magenta and contains at least one kind of magenta colorant appropriately selected.

[0091] Examples of coloring pigments for magenta include, for example, C.I. 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, 48:1, 49, 50, 51, 52, 53, 53:1, 54, 55, 57, 57:1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 150, 163, 177, 179, 184, 202, 206, 207, 209, 211, 269; C.I. Pigment Violet 19; C.I. Vat Red 1, 2, 10, 13, 15, 23, 29, 35, etc.

[0092] The content of the colorant in the toner is preferably 1% by mass to 15% by mass, more preferably 3% by mass to 10% by mass. If the content is less than 1% by mass, the coloring power of the toner may decrease. If it exceeds 15% by mass, poor dispersion of the colorant in the toner may occur, leading to a decrease in coloring power and a decrease in the electrical properties of the toner.

[0093] The colorant may be used as a masterbatch compounded with a resin. Such a resin is not particularly limited, but from the viewpoint of compatibility with the binder resin, it is preferable to use a binder resin or a resin having a structure similar to the binder resin.

[0094] The masterbatch can be produced by applying a high shear force to mix or knead the resin and the colorant. At this time, it is preferable to add an organic solvent to enhance the interaction between the colorant and the resin. Also, the so-called flushing method can directly use the wet cake of the colorant, which is suitable in that it does not require drying. The flushing method is a method of mixing or kneading an aqueous paste containing water of the colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing water and the organic solvent. For mixing or kneading, for example, a high shear dispersion device such as a three-roll mill can be used.

[0095] <Organically modified layered inorganic mineral> The organic-modified layered inorganic mineral is an organic-modified layered inorganic mineral in which at least a part of the ions present between the layers of the layered inorganic mineral is modified with organic ions. The layered inorganic mineral is a layered inorganic mineral formed by stacking layers with a thickness of several nm. The term "modified" is synonymous with introducing organic ions into the ions present between the layers of the layered inorganic mineral, and in a broad sense, it is intercalation.

[0096] The layered inorganic mineral exhibits the greatest effect when arranged near the surface, and it is known that it is likely to be arranged near the surface. Also, in the organic-modified layered inorganic mineral of the present invention, it is desirable to be contained in toner particles at a uniform ratio regardless of the size of the toner particle diameter. For this reason, the organic-modified layered inorganic mineral is uniformly arranged near the surface of any toner particle. As a result, for example, in toner particles with a small particle diameter, the content rate of the organic-modified layered inorganic mineral becomes small, so the ratio of the organic-modified layered inorganic mineral arranged on the surface decreases, the surface of the toner particle becomes relatively soft, and an external additive added to the toner matrix is easily embedded, thereby avoiding the phenomenon that the desorption of the external additive advantageous for imparting fluidity to the toner is inhibited.

[0097] Here, the state of existence of the organic-modified layered inorganic mineral in the toner can be confirmed by embedding a sample of toner particles in an epoxy resin or the like and cutting it with a microtome or an ultramicrotome, and observing the cross-section of the toner with a scanning electron microscope (SEM) or the like. In the case of observation by SEM, it is preferable to confirm with a backscattered electron image, because the presence of the organic-modified layered inorganic mineral can be observed with strong contrast. Also, using FIB-STEM (HD-2000, manufactured by Hitachi, Ltd.), a sample in which toner particles are embedded in an epoxy resin or the like may be cut with an ion beam and the cross-section of the toner may be observed. Also in this case, it is preferable to confirm with a backscattered electron image because of the ease of visual recognition.

[0098] In addition, the vicinity of the toner surface referred to in the present invention is defined as a region of 0 nm to 300 nm from the outermost surface of the toner to the inside of the toner in an observation image of a cross-section of the toner obtained by cutting a sample in which toner particles are embedded in an epoxy resin or the like with a microtome, an ultramicrotome, or a FIB-STEM.

[0099] The layered inorganic mineral is not particularly limited and can be appropriately selected according to the purpose. For example, smectite group clay minerals (montmorillonite, saponite, hectorite, etc.), kaolin group clay minerals (kaolinite, etc.), bentonite, attapulgite, magadiite, kanemite, etc. can be mentioned. These may be used alone or in combination of two or more.

[0100] The organically modified layered inorganic mineral is not particularly limited and can be appropriately selected according to the purpose. For example, organically modified layered inorganic minerals in which at least a part of the ions existing between the layers of these layered inorganic minerals are modified with organic ions can be mentioned. Among these, those in which at least a part of the ions between the layers of smectite group clay minerals having a smectite-based basic crystal structure are modified with organic cations are preferable from the viewpoint of dispersion stability in the vicinity of the toner surface. Particularly preferable are those in which at least a part of the ions between the layers of montmorillonite are modified with organic cations and those in which at least a part of the ions between the layers of bentonite are modified with organic cations.

[0101] The fact that at least a part of the ions existing between the layers of the layered inorganic mineral is modified with organic ions in the organically modified layered inorganic mineral can be confirmed by gas chromatography-mass spectrometry (GCMS). For example, a solution in which the binder resin in the toner as a sample is dissolved with a solvent is filtered, the obtained solid matter is thermally decomposed with a thermal decomposition device, and a method of identifying the structure of the organic matter with GCMS is preferably mentioned. Specifically, as the thermal decomposition device, Py-2020D (manufactured by Frontier Lab) is used, thermal decomposition is performed at 550°C, and then identification is performed with a GCMS device QP5000 (manufactured by Shimadzu Corporation).

[0102] In addition, examples of the organically modified layered inorganic mineral include a layered inorganic compound in which a part of the divalent metal of the layered inorganic mineral is replaced with a trivalent metal to introduce a metal anion, and at least a part of the metal anion is modified with an organic anion. Commercially available products can be used as the organically modified layered inorganic mineral. Examples of such commercially available products include quaternary ammonium 18 bentonite such as Bentone 3, Bentone 38, Bentone 38V (manufactured by Elementis Specialties), Thixogel VP (manufactured by United catalyst), Claytone 34, Claytone 40, Claytone XL (manufactured by Southern Clay); stearalkonium bentonite such as Bentone 27 (manufactured by Rheox), Thixogel LG (manufactured by BYK Additives & Instruments), Claytone AF, Claytone APA (manufactured by BYK Additives & Instruments); quaternary ammonium 18 / benzalkonium bentonite such as Claytone HT, Claytone PS (manufactured by Southern Clay); organically modified montmorillonite such as Claytone HY (manufactured by Southern Clay); organically modified saponite such as Lucentite SPN (manufactured by Coop Chemical), etc. Among these, Claytone AF and Claytone APA are particularly preferred.

[0103] In addition, as the organically modified layered inorganic mineral, those obtained by modifying DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.) with a compound having the organic ion represented by R1(OR2)nOSO3M (where R1 represents an alkyl group having 13 carbon atoms, R2 represents an alkylene group having 2 to 6 carbon atoms, n represents an integer of 2 to 10, and M represents a monovalent metal element) are particularly preferred. Examples of the compound having the organic ion represented by R1(OR2)nOSO3M include Hitenol 330T (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0104] The organically modified layered inorganic mineral may be mixed with a resin and used as a masterbatch that is compounded. The resin is not particularly limited and can be appropriately selected from known resins according to the purpose.

[0105] As the content of the organically modified layered inorganic mineral in the toner, 0.1% by mass to 3.0% by mass is preferable, and 0.3% by mass to 1.5% by mass is particularly preferable. When the content is less than 0.1% by mass, it is difficult to exert the effect of the layered inorganic mineral, and when it exceeds 3.0% by mass, there is a tendency to inhibit low-temperature fixability.

[0106] The organic ion modifier, which has the organic ions and can modify at least a part of the ions present between the layers of the layered inorganic mineral into organic ions, is not particularly limited and can be appropriately selected according to the purpose. Examples include quaternary alkylammonium salts, phosphonium salts, imidazolium salts; sulfates having skeletons such as branched, unbranched or cyclic alkyls with 1 to 44 carbon atoms, branched, unbranched or cyclic alkenyls with 1 to 22 carbon atoms, branched, unbranched or cyclic alkoxys with 8 to 32 carbon atoms, branched, unbranched or cyclic hydroxyalkyls with 2 to 22 carbon atoms, ethylene oxide, and propylene oxide, sulfonates having the skeleton, carboxylates having the skeleton, phosphates having the skeleton, and the like. Among these, quaternary alkylammonium salts and carboxylic acids having an ethylene oxide skeleton are preferable, and quaternary alkylammonium salts are particularly preferable. These may be used alone or in combination of two or more. Examples of the quaternary alkylammonium include trimethylstearylammonium, dimethylstearylbenzylammonium, dimethyloctadecylammonium, oleylbis(2-hydroxyethyl)methylammonium, and the like.

[0107] -Charge control agent- In addition, in order to impart appropriate charging ability to the toner, it is also possible to contain a charge control agent in the toner as necessary. As the charge control agent, any known charge control agent can be used. Since the color tone may change when a colored material is used, a material close to colorless or white is preferred. For example, triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, simple substances of phosphorus or their compounds, simple substances of tungsten or their compounds, fluorine-based activators, metal salts of salicylic acid, metal salts of salicylic acid derivatives, etc. can be mentioned. These may be used alone or in combination of two or more.

[0108] The content of the charge control agent is determined by the toner manufacturing method including the type of the binder resin and the dispersion method, and is not uniquely limited. However, 0.01% by mass to 5% by mass is preferred, and 0.02% by mass to 2% by mass is more preferred with respect to the binder resin. If the addition amount exceeds 5% by mass, the chargeability of the toner is too large, the effect of the charge control agent is reduced, the electrostatic attraction to the developing roller increases, which may cause a decrease in the fluidity of the developer and a decrease in the image density. If it is less than 0.01% by mass, the charge rising property and the charge amount are not sufficient, and it may easily affect the toner image.

[0109] <<External Additive>> There is no particular limitation on the external additive, and it can be appropriately selected from known ones according to the purpose. For example, silica fine particles, hydrophobized silica fine particles, fatty acid metal salts (such as zinc stearate, aluminum stearate, etc.); metal oxides (such as titania, alumina, tin oxide, antimony oxide, etc.) or their hydrophobized products, fluoropolymers, etc. can be mentioned. Among these, hydrophobized silica fine particles, titania particles, hydrophobized titania fine particles, are preferably mentioned.

[0110] Examples of the hydrophobized silica fine particles include HDK H2000T, HDK H2000 / 4, HDK H2050EP, HVK21, HDK H1303VP (all manufactured by Clariant Japan); R972, R974, RX200, RY200, R202, R805, R812, NX90G (all manufactured by Nippon Aerosil Co., Ltd.), and the like.

[0111] Examples of the titania fine particles include P-25 (manufactured by Nippon Aerosil Co., Ltd.); STT-30, STT-65C-S (both manufactured by Titanium Industry Co., Ltd.); TAF-140 (manufactured by Fuji Titanium Industry Co., Ltd.); MT-150W, MT-500B, MT-600B, MT-150A (all manufactured by Teika Corporation), and the like.

[0112] Examples of the hydrophobized titanium oxide fine particles include T-805 (manufactured by Nippon Aerosil Co., Ltd.); STT-30A, STT-65S-S (both manufactured by Titanium Industry Co., Ltd.); TAF-500T, TAF-1500T (both manufactured by Fuji Titanium Industry Co., Ltd.); MT-100S, MT-100T (both manufactured by Teika Corporation); IT-S (manufactured by Ishihara Sangyo Co., Ltd.), and the like.

[0113] The content of the external additive is not particularly limited and can be appropriately selected according to the purpose. However, with respect to 100 parts by mass of the toner base particles, 0.3 to 3.0 parts by mass is preferable, and 0.5 to 2.0 parts by mass is more preferable.

[0114] The total coating rate of the external additive with respect to the toner base particles is not particularly limited, but it is preferably 50% to 90%, and more preferably 60% to 80%.

[0115] <Method for manufacturing toner> In the present invention, as long as the conditions are satisfied, all known toner manufacturing methods and materials can be used, and there is no particular limitation. For example, there are a kneading and pulverizing method and a so-called chemical method in which toner particles are granulated in an aqueous medium.

[0116] Examples of the chemical method include suspension polymerization, emulsion polymerization, seed polymerization, dispersion polymerization, etc. that produce using monomers as starting materials; the solution suspension method that dissolves a resin or resin precursor in an organic solvent or the like and disperses or emulsifies it in an aqueous medium; in the solution suspension method, an oil phase composition containing a resin precursor (reactive group-containing prepolymer) having a functional group capable of reacting with an active hydrogen group is emulsified or dispersed in an aqueous medium containing resin fine particles, and in this aqueous medium, an active hydrogen group-containing compound and the reactive group-containing prepolymer are reacted (ester extension method); the phase inversion emulsification method that adds water to a solution composed of a resin or resin precursor and a suitable emulsifier to cause phase inversion; the aggregation method that aggregates resin particles obtained by these methods in a state of being dispersed in an aqueous medium and granulates them into particles of a desired size by heating and melting or the like. Among these, toners obtained by the solution suspension method, the ester extension method, and the aggregation method are preferable from the viewpoint of granulation properties (control of particle size distribution, control of particle shape, etc.), and the toner obtained by the ester extension method is more preferable. Details of these production methods will be described below.

[0117] The kneading and pulverizing method is, for example, a method for producing the base particles of the toner by melting and kneading a toner material having at least a colorant, a binder resin, and a release agent, and then pulverizing and classifying it.

[0118] In the above melt kneading, the toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a single-screw or twin-screw continuous kneader or a batch kneader using a roll mill can be used. For example, the KTK type twin-screw extruder manufactured by Kobe Steel, Ltd., the TEM type extruder manufactured by Toshiba Machine Co., Ltd., the twin-screw extruder manufactured by CKC Co., Ltd., the PCM type twin-screw extruder manufactured by Ikegai Iron Works, Ltd., the conical kneader manufactured by Buss Co., Ltd., etc. are preferably used. This melt kneading is preferably performed under appropriate conditions so as not to cause cleavage of the molecular chains of the binder resin. Specifically, the melt kneading temperature is determined with reference to the softening point of the binder resin. If it is too high above the softening point, cleavage will be severe, and if it is too low, dispersion may not proceed.

[0119] In the above-mentioned pulverization, the kneaded product obtained in the above-mentioned kneading is pulverized. In this pulverization, it is preferable to first coarsely pulverize the kneaded product and then finely pulverize it. At this time, a method of pulverizing by colliding with a collision plate in a jet air flow, a method of pulverizing by colliding particles with each other in a jet air flow, or a method of pulverizing in a narrow gap between a mechanically rotating rotor and a stator is preferably used.

[0120] The above-mentioned classification classifies the pulverized product obtained in the above-mentioned pulverization and adjusts it to particles having a predetermined particle size. The above-mentioned classification can be performed, for example, by removing fine particle portions using a cyclone, a decanter, a centrifuge, or the like. After the above-mentioned pulverization is completed, the pulverized product can be classified in an air flow by centrifugal force or the like to produce toner base particles having a predetermined particle size.

[0121] The above-mentioned dissolution suspension method is, for example, a method of producing toner base particles by dispersing or emulsifying an oil phase composition in which a toner composition containing at least a binder resin or a resin precursor, a colorant, and a release agent is dissolved or dispersed in an organic solvent in an aqueous medium.

[0122] As the organic solvent used when dissolving or dispersing the above-mentioned toner composition, it is preferable that the boiling point is less than 100 °C and volatile, from the viewpoint of facilitating subsequent solvent removal. Examples of the organic solvent include ester-based or ester-ether-based solvents such as ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, and ethyl cellosolve acetate; ether-based solvents such as diethyl ether, tetrahydrofuran, dioxane, ethyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone, and cyclohexanone; alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 2-ethylhexyl alcohol, and benzyl alcohol; and mixed solvents of two or more of these.

[0123] In the dissolution-suspension method, when dispersing or emulsifying the oil-phase composition in an aqueous medium, an emulsifier or a dispersant may be used as necessary. As the emulsifier or dispersant, known surfactants, water-soluble polymers, etc. can be used. There are no particular restrictions on the surfactant, and examples include anionic surfactants (such as alkylbenzene sulfonic acid, phosphate esters, etc.), cationic surfactants (such as quaternary ammonium salt type, amine salt type, etc.), amphoteric surfactants (such as carboxylate type, sulfate ester salt type, sulfonate type, phosphate ester salt type, etc.), nonionic surfactants (such as AO addition type, polyhydric alcohol type, etc.), and the like. The surfactant may be used alone or in combination of two or more surfactants.

[0124] Examples of the water-soluble polymer include cellulose-based compounds (such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and saponified products thereof), gelatin, starch, dextrin, gum arabic, chitin, chitosan, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polyethylene imine, polyacrylamide, polymers containing acrylic acid (salt) (such as sodium polyacrylate, potassium polyacrylate, ammonium polyacrylate, partially neutralized sodium hydroxide of polyacrylic acid, sodium acrylate-acrylic acid ester copolymer), sodium hydroxide (partial) neutralized product of styrene-maleic anhydride copolymer, water-soluble polyurethane (reaction product of polyethylene glycol, polycaprolactone diol, etc. and polyisocyanate, etc.), and the like. In addition, as an auxiliary agent for emulsification or dispersion, the above-mentioned organic solvents, plasticizers, etc. can also be used in combination.

[0125] The toner according to the present invention is obtained preferably by granulating the mother particles of the toner by a method (ester extension method) in which, in a dissolution suspension method, an oil phase composition containing at least a binder resin, a binder resin precursor having a functional group capable of reacting with an active hydrogen group (reactive group-containing prepolymer), a colorant, and a release agent is dispersed or emulsified in an aqueous medium containing resin fine particles, and the active hydrogen group-containing compound contained in the oil phase composition and / or the aqueous medium is reacted with the reactive group-containing prepolymer.

[0126] The resin fine particles can be formed using known polymerization methods, but it is preferable to obtain them as an aqueous dispersion of the resin fine particles. Examples of the method for preparing the aqueous dispersion of the resin fine particles include the methods shown in the following (a) to (h). (a) A method of directly preparing an aqueous dispersion of resin fine particles by a polymerization reaction such as a suspension polymerization method, an emulsion polymerization method, a seed polymerization method, or a dispersion polymerization method using a vinyl monomer as a starting material. (b) A method of preparing an aqueous dispersion of resin fine particles by dispersing a precursor (monomer, oligomer, etc.) of a polyaddition or condensation resin such as a polyester resin, a polyurethane resin, or an epoxy resin or a solvent solution thereof in an aqueous medium in the presence of a suitable dispersant, and then heating or adding a curing agent to cure it. (c) A method of preparing an aqueous dispersion of resin fine particles by dissolving a suitable emulsifier in a precursor (monomer, oligomer, etc.) of a polyaddition or condensation resin such as a polyester resin, a polyurethane resin, or an epoxy resin or a solvent solution thereof (preferably a liquid, which may be liquefied by heating), adding water, and performing phase inversion emulsification. (d) A method of preparing an aqueous dispersion of resin fine particles by pulverizing and classifying a resin synthesized in advance by a polymerization reaction (for example, addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) using a fine pulverizer such as a mechanical rotation type or a jet type, and then dispersing it in water in the presence of a suitable dispersant. (e) A method of preparing an aqueous dispersion of resin fine particles, which comprises forming resin fine particles by spraying a resin solution obtained by dissolving a resin synthesized in advance by a polymerization reaction (for example, addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) in a solvent in a mist form, and then dispersing the resin fine particles in water in the presence of a suitable dispersant. (f) A method of preparing an aqueous dispersion of resin fine particles, which comprises adding a poor solvent to a resin solution obtained by dissolving a resin synthesized in advance by a polymerization reaction (for example, addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) in a solvent, or cooling a resin solution obtained by heating and dissolving a resin in a solvent in advance to precipitate resin fine particles, removing the solvent to form resin fine particles, and then dispersing the resin fine particles in water in the presence of a suitable dispersant. (g) A method of preparing an aqueous dispersion of resin fine particles, which comprises dispersing a resin solution obtained by dissolving a resin synthesized in advance by a polymerization reaction (for example, addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) in a solvent in an aqueous medium in the presence of a suitable dispersant, and then removing the solvent by heating, reduced pressure, etc. (h) A method of preparing an aqueous dispersion of resin fine particles, which comprises dissolving a suitable emulsifier in a resin solution obtained by dissolving a resin synthesized in advance by a polymerization reaction (for example, addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) in a solvent, adding water to carry out phase inversion emulsification.

[0127] The volume average particle diameter of the resin fine particles is preferably 10 nm or more and 300 nm or less, more preferably 30 nm or more and 120 nm or less. When the volume average particle diameter of the resin fine particles is 10 nm or more (especially 30 nm or more) and 300 nm or less (especially 120 nm or less), the particle size distribution of the toner does not deteriorate, which is preferable.

[0128] The solid content concentration of the oil phase is preferably about 40 to 80%. If the concentration is too high, dissolution or dispersion becomes difficult, and the viscosity becomes high, making it difficult to handle. If the concentration is too low, the productivity of the toner decreases.

[0129] Toner compositions other than the binder resin, such as the colorant and release agent, and organically modified layered inorganic minerals, and their masterbatches, etc., may be individually dissolved or dispersed in an organic solvent and then mixed with the binder resin solution or dispersion.

[0130] As the aqueous medium, water alone may be used, but a solvent miscible with water can also be used in combination. Examples of miscible solvents include alcohols (such as methanol, isopropanol, and ethylene glycol), dimethylformamide, tetrahydrofuran, cellosolves (such as methyl cellosolve), and lower ketones (such as acetone and methyl ethyl ketone).

[0131] The method of dispersing or emulsifying into the aqueous medium is not particularly limited, and known equipment such as low-speed shearing type, high-speed shearing type, friction type, high-pressure jet type, and ultrasonic can be applied. Among them, from the viewpoint of reducing the particle size, the high-speed shearing type is preferable. When using a high-speed shearing type disperser, the rotation speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The temperature during dispersion is usually 0 to 150 °C (under pressure), preferably 20 to 80 °C.

[0132] In order to remove the organic solvent from the obtained emulsion dispersion, there is no particular limitation, and known methods can be used. For example, the temperature of the whole system can be gradually increased while stirring under normal pressure or reduced pressure to completely evaporate and remove the organic solvent in the droplets.

[0133] As a method for washing and drying the toner base particles dispersed in an aqueous medium, known techniques are used. That is, after solid-liquid separation using a centrifuge, a filter press, etc., the obtained toner cake is redispersed in ion-exchanged water at room temperature to about 40 °C, and after adjusting the pH with an acid or an alkali as necessary, the step of performing solid-liquid separation again is repeated several times to remove impurities, surfactants, etc., and then the toner powder is obtained by drying with an air flow dryer, a circulation dryer, a vacuum dryer, a vibration fluidized dryer, etc. At this time, the fine particle components of the toner may be removed by centrifugation or the like, and also, after drying, a desired particle size distribution can be obtained using a known classifier as necessary.

[0134] In the aggregation method, for example, it is a method of producing toner base particles by mixing and aggregating at least a resin fine particle dispersion composed of a binder resin, a colorant particle dispersion, and, if necessary, a release agent particle dispersion. The resin fine particle dispersion is obtained by a known method, for example, emulsion polymerization, seed polymerization, phase inversion emulsification method, etc., and the colorant particle dispersion and the release agent particle dispersion are obtained by dispersing a colorant and a release agent in an aqueous medium by a known wet dispersion method or the like.

[0135] For the control of the aggregated state, methods such as applying heat, adding a metal salt, and adjusting the pH are preferably used. There is no particular limitation on the metal salt, and examples include monovalent metals constituting salts such as sodium and potassium; divalent metals constituting salts such as calcium and magnesium; trivalent metals constituting salts such as aluminum. Examples of the anion constituting the salt include chloride ion, bromide ion, iodide ion, carbonate ion, and sulfate ion. Among these, magnesium chloride, aluminum chloride, and their complexes and multimers are preferable. In addition, by heating during or after the aggregation, the fusion of the resin fine particles can be promoted, which is preferable from the viewpoint of the uniformity of the toner. Furthermore, the shape of the toner can be controlled by heating, and usually, the more heating is performed, the closer the toner becomes to a spherical shape.

[0136] As for the method of cleaning and drying the toner base particles dispersed in the aqueous medium, the above-described methods or the like can be used.

[0137] In addition, in order to improve the fluidity, storage stability, developability, and transferability of the toner, inorganic fine particles such as hydrophobic silica fine powder may be added to and mixed with the toner base particles manufactured as described above. For mixing the additive, a general powder mixer is used, but it is preferably equipped with a jacket or the like so that the internal temperature can be adjusted. In order to change the history of the load applied to the additive, the additive may be added halfway or gradually. In this case, the rotation speed, rolling speed, time, temperature, etc. of the mixer may be changed. Alternatively, a strong load may be applied first and then a relatively weak load, or vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Lodige mixer, a Nauta mixer, a Henschel mixer, and the like. Next, the toner is obtained by passing it through a sieve of 250 mesh or more to remove coarse particles and aggregated particles.

[0138] (Developer) The developer of the present invention comprises at least the above toner and appropriately selected other components such as a carrier. The developer may be a one-component developer or a two-component developer. However, when used in a high-speed printer or the like corresponding to the recent improvement in information processing speed, the two-component developer is preferable in terms of improving the life and the like.

[0139] In the case of the one-component developer using the above toner, toner aggregates are less likely to be generated over time even with respect to stress by developing means, and there is no toner filming on the developing roller as a developer carrier or toner fusion on a layer thickness regulating member such as a blade for thinning the toner layer. By maintaining good image density stability and transferability, good and stable image quality can be obtained. Also, in the case of the two-component developer using the above toner, toner aggregates are less likely to be generated over time even with respect to agitation stress by developing means, the occurrence of abnormal images is suppressed, and by maintaining good image density stability and transferability, good and stable image quality can be obtained.

[0140] <Carrier> The carrier is not particularly limited and can be appropriately selected according to the purpose. However, those having a core particle and a resin layer (coating layer) that coats the core particle are preferred.

[0141] <<Core particle>> The core particle is not particularly limited as long as it is a magnetic core particle and can be appropriately selected according to the purpose. For example, ferromagnetic metals such as iron and cobalt; iron oxides such as magnetite, hematite, and ferrite; resin particles in which magnetic materials such as various alloys and compounds are dispersed in a resin, and the like can be mentioned. Among these, from the viewpoint of environmental considerations, Mn-based ferrite, Mn-Mg-based ferrite, Mn-Mg-Sr-based ferrite, etc. are preferred.

[0142] -Weight average particle diameter Dw of the core particle- The weight average particle diameter Dw of the core particle refers to the particle diameter at the integrated value of 50% in the particle size distribution of the core particle obtained by the laser diffraction or scattering method. The weight average particle diameter Dw of the core particle is not particularly limited and can be appropriately selected according to the purpose. However, 10 μm to 80 μm is preferred, and 20 μm to 65 μm is more preferred.

[0143] The measurement of the weight average particle diameter Dw of the core particle is carried out by measuring the particle size distribution (relationship between the number frequency and the particle diameter) of the particles measured on a number basis using a Microtrac particle size distribution analyzer (HRA9320-X100, manufactured by Honeywell) under the conditions described below, and calculating using the following formula (I). Each channel represents the length for dividing the particle size range in the particle size distribution diagram into units of the measurement width, and the representative particle diameter adopts the lower limit value of the particle diameter stored in each channel.

[0144] Dw = {1 / Σ(nD3)} × {Σ(nD4)} ···(I) However, in the formula (I), D represents the representative particle diameter (μm) of the core particles present in each channel, and n represents the total number of core particles present in each channel.

[0145] [Measurement conditions] [1] Particle size range: 100μm to 8μm [2] Channel length (channel width): 2μm [3] Number of channels: 46 [4] Refractive index: 2.42 [[Coating layer]] The coating layer contains at least resin and may contain other components such as fillers as required.

[0146] - Resin - There are no particular restrictions on the resin for forming the coating layer of the carrier, and it can be appropriately selected according to the purpose. For example, polyolefins (such as polyethylene, polypropylene, etc.) and their modified products, polystyrene, acrylic resins, acrylonitrile, vinyl acetate, vinyl alcohol, vinyl chloride, vinyl carbazole, vinyl ether, etc. including crosslinkable copolymers; silicone resins composed of organosiloxane bonds or their modified products (such as modified products with alkyd resins, polyester resins, epoxy resins, polyurethanes, polyimides, etc.); polyamides; polyesters; polyurethanes; polycarbonates; urea resins; melamine resins; benzoguanamine resins; epoxy resins; ionomer resins; polyimide resins, and their derivatives, etc. These may be used alone or in combination of two or more. Among these, silicone resins are preferred.

[0147] There are no particular restrictions on the silicone resin, and it can be appropriately selected from generally known silicone resins according to the purpose. For example, straight silicone resins composed only of organosiloxane bonds, and silicone resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. are mentioned.

[0148] Examples of the straight silicone resin include KR271, KR272, KR282, KR252, KR255, KR152 (manufactured by Shin-Etsu Chemical Co., Ltd.), SR2400, SR2405, SR2406 (manufactured by Toray Dow Corning Silicone Co., Ltd.).

[0149] In addition, specific examples of the modified silicone resin include epoxy-modified product: ES-1001N, acrylic-modified silicone: KR-5208, polyester-modified product: KR-5203, alkyd-modified product: KR-206, urethane-modified product: KR-305 (all manufactured by Shin-Etsu Chemical Co., Ltd.), epoxy-modified product: SR2115, alkyd-modified product: SR2110 (manufactured by Toray Dow Corning Silicone Co., Ltd.), etc.

[0150] The silicone resin can be used alone, but it is also possible to use crosslinking reactive components, charge amount adjusting components, etc. simultaneously. Examples of the crosslinking reactive components include silane coupling agents. Examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, octyltrimethoxysilane, aminosilane coupling agent, etc.

[0151] -Filler- The filler is not particularly limited and can be appropriately selected according to the purpose. Examples include conductive fillers, non-conductive fillers, etc. These can be used alone or in combination of two or more. Among these, it is preferable to contain a conductive filler and a non-conductive filler in the coating layer.

[0152] The conductive filler refers to a filler having a powder specific resistance value of 100 Ω·cm or less. The non-conductive filler refers to a filler having a powder specific resistance value exceeding 100 Ω·cm. The measurement of the powder specific resistance value of the filler can be carried out by using a powder resistance measurement system (MCP-PD51, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and a resistivity meter (4-terminal 4-probe method, Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) under the conditions of a sample of 1.0 g, an electrode interval of 3 mm, a sample radius of 10.0 mm, and a load of 20 kN.

[0153] --Conductive Filler-- The conductive filler is not particularly limited and can be appropriately selected according to the purpose. For example, a conductive filler formed by forming tin dioxide or indium oxide as a layer on a substrate such as aluminum oxide, titanium oxide, zinc oxide, barium sulfate, silicon oxide, zirconium oxide, etc.; a conductive filler formed using carbon black, etc. Among these, a conductive filler containing aluminum oxide, titanium oxide, and barium sulfate is preferable.

[0154] --Non-conductive filler-- The non-conductive filler is not particularly limited and can be appropriately selected according to the purpose. For example, a non-conductive filler formed using aluminum oxide, titanium oxide, barium sulfate, zinc oxide, silicon dioxide, zirconium oxide, etc. Among these, a non-conductive filler containing aluminum oxide, titanium oxide, and barium sulfate is preferable.

[0155] <Method for manufacturing the carrier> The method for manufacturing the carrier is not particularly limited and can be appropriately selected according to the purpose. However, a method of manufacturing by applying a coating layer forming solution containing the resin and the filler to the surface of the core particles using a fluidized bed type coating device is preferable. When applying the coating layer forming solution, the condensation of the resin contained in the coating layer may be advanced, or after applying the coating layer forming solution, the condensation of the resin contained in the coating layer may be advanced.

[0156] The method for condensing the resin is not particularly limited and can be appropriately selected according to the purpose. For example, a method of condensing the resin by applying heat, light, etc. to the coating layer forming solution can be mentioned.

[0157] -Weight average particle diameter Dw of the carrier- The weight average particle diameter Dw of the carrier refers to the particle diameter at 50% of the integrated value in the particle size distribution of the core particles determined by the laser diffraction / scattering method. The weight average particle diameter Dw of the carrier is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10 μm to 80 μm, and more preferably 20 μm to 65 μm.

[0158] The measurement of the weight average particle diameter Dw of the carrier is carried out by measuring the particle size distribution (relationship between number frequency and particle diameter) of the particles measured on a number basis using a Microtrac particle size distribution analyzer (HRA9320-X100, manufactured by Honeywell) under the conditions described below, and calculating using the following formula (II). Each channel represents the length for dividing the particle size range in the particle size distribution diagram into measurement width units, and the representative particle diameter adopts the lower limit value of the particle size stored in each channel.

[0159] Dw = {1 / Σ(nD3)} × {Σ(nD4)} ···(II) However, in the formula (II), D represents the representative particle diameter (μm) of the carrier present in each channel, and n represents the total number of carriers present in each channel.

[0160] [Measurement conditions] [1] Particle size range: 100 μm to 8 μm [2] Channel length (channel width): 2 μm [3] Number of channels: 46 [4] Refractive index: 2.42

[0161] When the developer is a two-component developer, the mixing ratio of toner and carrier in the two-component developer is preferably such that the mass ratio of toner to carrier is 2.0 to 12.0% by mass, and more preferably 2.5 to 10.0% by mass.

[0162] (Toner storage unit) The toner storage unit in the present invention refers to a unit having a function of storing toner, which contains the stored toner. Here, examples of the form of the toner storage unit include a toner storage container, a developing device, and a process cartridge. The toner storage container refers to a container that stores toner. The developing device refers to a device having means for storing and developing toner. The process cartridge refers to a unit that integrates at least an electrostatic latent image carrier (also referred to as an image carrier) and developing means, stores toner, and is detachable from the image forming apparatus. The process cartridge may further include at least one selected from charging means, exposure means, and cleaning means.

[0163] By mounting the toner storage unit of the present invention on an image forming apparatus and forming an image, since image formation is performed using the toner of the present invention, it is possible to suppress toner scattering and enable low-temperature fixing.

[0164] (Image Forming Method and Image Forming Apparatus) The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image using the toner or developer of the present invention to form a visible image, a transfer step of transferring the visible image onto a recording medium, and a fixing step of fixing the transferred image on the recording medium. Further, it has other steps appropriately selected as necessary, such as a charge removal step, a cleaning step, a recycling step, a control step, etc.

[0165] The image forming apparatus of the present invention includes an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, a developing means for developing the electrostatic latent image using the toner or developer of the present invention to form a visible image, a transfer means for transferring the visible image onto a recording medium, and a fixing means for fixing the transferred image on the recording medium. Further, it has other means appropriately selected as necessary, such as a charge removal means, a cleaning means, a recycling means, a control means, etc. Details will be described below.

[0166] -Electrostatic Latent Image Forming Step and Electrostatic Latent Image Forming Means- The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image carrier. As the electrostatic latent image carrier (which may be referred to as an "electrophotographic photoreceptor" or "photoreceptor"), there are no particular restrictions on its material, shape, structure, size, etc., and it can be appropriately selected from known ones. As its shape, a drum shape is preferably mentioned. As its material, for example, inorganic photoreceptors such as amorphous silicon and selenium, organic photoreceptors (OPC) such as polysilane and phthalopolymethine, etc. can be mentioned. Among these, an organic photoreceptor (OPC) is preferable in terms of obtaining a higher-definition image.

[0167] The formation of the electrostatic latent image can be carried out, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it imagewise, and can be carried out by an electrostatic latent image forming means. The electrostatic latent image forming means includes, for example, at least a charging means (charger) for uniformly charging the surface of the electrostatic latent image carrier and an exposure means (exposure device) for exposing the surface of the electrostatic latent image carrier imagewise.

[0168] The charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger. There are no particular restrictions on the charger, and it can be appropriately selected according to the purpose. For example, known contact chargers equipped with conductive or semiconductive rolls, brushes, films, rubber blades, etc., non-contact chargers using corona discharge such as corotrons and scorotrons, etc. can be mentioned. As the charger, it is preferably arranged in contact or non-contact with the electrostatic latent image carrier and charges the surface of the electrostatic latent image carrier by superimposing and applying DC and AC voltages. Also, it is preferable that the charger is a charging roller arranged in non-contact proximity to the electrostatic latent image carrier via a gap tape, and charges the surface of the electrostatic latent image carrier by superimposing and applying DC and AC voltages to the charging roller.

[0169] The exposure can be performed, for example, by imagewise exposing the surface of the electrostatic latent image carrier using the exposure device. The exposure device is not particularly limited as long as it can perform imagewise exposure on the surface of the electrostatic latent image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples thereof include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. In the present invention, a light backside exposure method in which imagewise exposure is performed from the backside of the electrostatic latent image carrier may be adopted.

[0170] - Development step and development means - The development step is a step of developing the electrostatic latent image using the toner to form a visible image. The formation of the visible image can be performed, for example, by developing the electrostatic latent image using the toner, and can be performed by the developing means. The developing means preferably includes, for example, at least a developing device that houses the toner and can apply the toner to the electrostatic latent image in a contact or non-contact manner, and a developing device provided with a toner-containing container is more preferable.

[0171] The developing device may be a single-color developing device or a multi-color developing device. Examples thereof preferably include those having a stirrer that stirs and charges the toner by frictional agitation and a rotatable magnet roller. In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner is charged by the friction at that time and is held in a standing state on the surface of the rotating magnet roller to form a magnetic brush. Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier (photoconductor), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller moves to the surface of the electrostatic latent image carrier (photoconductor) by an electric attractive force. As a result, the electrostatic latent image is developed by the toner, and a visible image by the toner is formed on the surface of the electrostatic latent image carrier (photoconductor).

[0172] - Transfer process and transfer means - The transfer process is a process of transferring the visible image onto a recording medium. It is preferably a mode in which an intermediate transfer member is used, the visible image is first transferred onto the intermediate transfer member, and then the visible image is secondarily transferred onto the recording medium. It is more preferable to use two or more colors of toner, preferably full-color toner, and including a first transfer process of transferring the visible image onto the intermediate transfer member to form a composite transfer image, and a second transfer process of transferring the composite transfer image onto the recording medium. The transfer can be performed, for example, by charging the electrostatic latent image carrier (photoconductor) using a transfer charger to charge the electrostatic latent image carrier (photoconductor), and can be performed by the transfer means. As the transfer means, a mode having a first transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image and a second transfer means for transferring the composite transfer image onto a recording medium is preferable. Note that there is no particular limitation on the intermediate transfer member, and it can be appropriately selected from known transfer members according to the purpose. For example, a transfer belt or the like is preferably mentioned.

[0173] The transfer means (the first transfer means, the second transfer means) preferably has at least a transfer device that peels and charges the visible image formed on the electrostatic latent image carrier (photoconductor) toward the recording medium side. The transfer means may be one or two or more. Examples of the transfer device include a corona transfer device by corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, an adhesive transfer device, and the like. Note that there is no particular limitation on the recording medium, and it can be appropriately selected from known recording media (recording paper).

[0174] - Fixing process and fixing means - The fixing process is a process of fixing the visible image transferred to the recording medium using a fixing device, and it may be performed each time it is transferred to the recording medium for each color developer, or may be performed simultaneously at once in a stacked state for each color developer. The fixing device is not particularly limited and can be appropriately selected according to the purpose, but known heating and pressing means are preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller, and an endless belt, and the like. It is preferable that the fixing device includes a heating member having a heating element, a film in contact with the heating member, and a pressing member that presses against the heating member via the film, and is a means for heating and fixing by passing a recording medium on which an unfixed image is formed between the film and the pressing member. The heating in the heating and pressing means is usually preferably 80°C to 200°C. In the present invention, depending on the purpose, a known light fixing device may be used, for example, together with or instead of the fixing step and the fixing means.

[0175] The discharging step is a step of discharging the electrostatic latent image carrier by applying a discharging bias, and can be preferably performed by a discharging means. The discharging means is not particularly limited as long as it can apply a discharging bias to the electrostatic latent image carrier, and can be appropriately selected from known dischargers. For example, a discharging lamp is preferably mentioned.

[0176] The cleaning step is a step of removing the toner remaining on the electrostatic latent image carrier, and can be preferably performed by a cleaning means. The cleaning means is not particularly limited as long as it can remove the toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, a web cleaner, etc. are preferably mentioned.

[0177] The recycling step is a step of recycling the toner removed in the cleaning step to the developing means, and can be preferably performed by a recycling means. The recycling means is not particularly limited, and examples include known conveying means. The control step is a step of controlling each of the above steps, and each step can be preferably performed by control means. The control means is not particularly limited as long as it can control the movement of each of the above means, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

[0178] FIG. 5 shows a first example of the image forming apparatus of the present invention. The image forming apparatus 100A includes a photosensitive drum 10, a charging roller 20, an exposure device 30, a developing device 40, an intermediate transfer belt 50, a cleaning device 60 having a cleaning blade, and a charge removing lamp 70.

[0179] The intermediate transfer belt 50 is an endless belt stretched by three rollers 51 arranged inside, and can move in the direction of the arrow in the figure. A part of the three rollers 51 also functions as a transfer bias roller capable of applying a transfer bias (primary transfer bias) to the intermediate transfer belt 50. Further, a cleaning device 90 having a cleaning blade is arranged in the vicinity of the intermediate transfer belt 50. Furthermore, a transfer roller 80 capable of applying a transfer bias (secondary transfer bias) for transferring the toner image to the transfer paper 95 is arranged opposite to the intermediate transfer belt 50.

[0180] Further, around the intermediate transfer belt 50, a corona charging device 58 for charging the toner image transferred to the intermediate transfer belt 50 is arranged between the contact portion of the photosensitive drum 10 and the intermediate transfer belt 50 and the contact portion of the intermediate transfer belt 50 and the transfer paper 95 with respect to the rotation direction of the intermediate transfer belt 50.

[0181] The developing device 40 is composed of a developing belt 41 and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C provided around the developing belt 41. Each color developing unit 45 includes a developer storage section 42, a developer supply roller 43, and a developing roller (developer carrier) 44. The developing belt 41 is an endless belt stretched by a plurality of belt rollers and can move in the direction of the arrow in the figure. Further, a part of the developing belt 41 is in contact with the photosensitive drum 10.

[0182] Next, a method of forming an image using the image forming apparatus 100A will be described. First, after uniformly charging the surface of the photosensitive drum 10 using the charging roller 20, the photosensitive drum 10 is exposed to the exposure light L using the exposure device to form an electrostatic latent image. Next, the electrostatic latent image formed on the photosensitive drum 10 is developed with toner supplied from the developing device 40 to form a toner image. Further, after the toner image formed on the photosensitive drum 10 is transferred (primary transfer) onto the intermediate transfer belt 50 by the transfer bias applied from the roller 51, it is transferred (secondary transfer) onto the transfer paper 95 by the transfer bias applied from the transfer roller 80. On the other hand, the photosensitive drum 10 onto which the toner image has been transferred to the intermediate transfer belt 50 is discharged by the discharge lamp 70 after the toner remaining on the surface has been removed by the cleaning device 60.

[0183] FIG. 6 shows a second example of the image forming apparatus used in the present invention. The image forming apparatus 100B has the same configuration as the image forming apparatus 100A except that the developing belt 41 is not provided and the black developing unit 45K, the yellow developing unit 45Y, the magenta developing unit 45M, and the cyan developing unit 45C are directly opposed and arranged around the photosensitive drum 10.

[0184] FIG. 7 shows a third example of the image forming apparatus used in the present invention. The image forming apparatus 100C is a tandem type color image forming apparatus and includes a copying machine main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

[0185] The intermediate transfer belt 50 provided at the central part of the copying apparatus main body 150 is an endless belt stretched over three rollers 14, 15 and 16, and can move in the direction of the arrow in the figure. Near the roller 15, a cleaning device 17 having a cleaning blade for removing toner remaining on the intermediate transfer belt 50 onto which the toner image has been transferred to the recording paper is disposed. Opposite to the intermediate transfer belt 50 stretched by the rollers 14 and 15 and along the conveyance direction, the image forming units 18Y, 18C, 18M and 18K for yellow, cyan, magenta and black are juxtaposed to form a tandem type image forming unit 120.

[0186] Also, an exposure device 21 is disposed near the image forming unit 120. Further, on the side opposite to the side where the image forming unit 120 of the intermediate transfer belt 50 is disposed, a secondary transfer belt 24 is disposed. Note that the secondary transfer belt 24 is an endless belt stretched over a pair of rollers 23, and the recording paper conveyed on the secondary transfer belt 24 and the intermediate transfer belt 50 can come into contact with each other between the rollers 16 and 23.

[0187] Also, near the secondary transfer belt 24, a fixing device 25 including a fixing belt 26 which is an endless belt stretched over a pair of rollers and a pressure roller 27 disposed to be pressed against the fixing belt 26 is disposed. Note that near the secondary transfer belt 24 and the fixing device 25, a sheet reversing device 28 for reversing the recording paper when forming images on both sides of the recording paper is disposed.

[0188] Next, a method for forming a full-color image using the image forming apparatus 100C will be described. First, place a color document on the document table 130 of the automatic document feeder (ADF) 400, or open the automatic document feeder 400 and set the color document on the contact glass 32 of the scanner 300, and then close the automatic document feeder 400. When the start switch is pressed, if a document is set on the automatic document feeder 400, the document is conveyed and moved onto the contact glass 32. On the other hand, if a document is set on the contact glass 32, the scanner 300 is immediately driven, and the first traveling body 33 equipped with a light source and the second traveling body 34 equipped with a mirror travel. At this time, after the reflected light of the light irradiated from the first traveling body 33 from the document surface is reflected by the second traveling body 34, it is received by the reading sensor 36 through the imaging lens 35, so that the document is read, and image information of black, yellow, magenta, and cyan is obtained.

[0189] The image information of each color is transmitted to the image forming unit 120 of each color, and a toner image of each color is formed. As shown in FIG. 8, each image forming unit 120 of each color includes a photosensitive drum 10, a charging roller 160 for uniformly charging the photosensitive drum 10, an exposure device for exposing the photosensitive drum 10 to the exposure light L based on the image information of each color to form an electrostatic latent image of each color, a developing device 61 for developing the electrostatic latent image with a developer of each color to form a toner image of each color, a transfer roller 62 for transferring the toner image onto the intermediate transfer belt 50, a cleaning device 63 having a cleaning blade, and a charge elimination lamp 64.

[0190] The toner images of each color formed by the image forming units 120 of each color are sequentially transferred (primary transfer) onto the intermediate transfer body 50 that moves while being stretched over the rollers 14, 15, and 16, and are overlapped to form a composite toner image.

[0191] On one hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed out the recording paper from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, separated one by one by the separation roller 145, sent out to the paper feed path 146, conveyed by the conveyance roller 147, guided to the paper feed path 148 in the copier main body 150, and abutted against the registration roller 49 to stop. Alternatively, the paper feed roller is rotated to feed out the recording paper on the manual feed tray 54, separated one by one by the separation roller 52, guided to the manual paper feed path 53, and abutted against the registration roller 49 to stop.

[0192] Note that the registration roller 49 is generally used while being grounded, but it may also be used in a state where a bias is applied to remove the paper dust of the recording paper. Next, by rotating the registration roller 49 in synchronization with the composite toner image formed on the intermediate transfer belt 50, the recording paper is sent out between the intermediate transfer belt 50 and the secondary transfer belt 24, and the composite toner image is transferred (secondary transfer) onto the recording paper. Note that the toner remaining on the intermediate transfer belt 50 after transferring the composite toner image is removed by the cleaning device 17.

[0193] The recording paper onto which the composite toner image is transferred is conveyed by the secondary transfer belt 24 and then the composite toner image is fixed by the fixing device 25. Next, the conveyance path of the recording paper is switched by the switching claw 55 and discharged onto the paper discharge tray 57 by the discharge roller 56. Alternatively, the conveyance path of the recording paper is switched by the switching claw 55, reversed by the sheet reversing device 28, and after an image is similarly formed on the back side, it is discharged onto the paper discharge tray 57 by the discharge roller 56.

[0194] According to the image forming method and image forming apparatus of the present invention, a high-quality image can be provided over a long period of time.

[0195] The present invention relates to the magenta toner of the following (1), and includes the following (2) to (8) as embodiments. (1) A magenta toner containing at least a binder resin and a colorant, and in the Raman spectroscopy of the magenta toner, 1200 cm-1 ~3250 cm -1 When the intensity of the Raman spectrum of each toner particle in the wavenumber region of is added up and the total intensity shows a maximum value, and the intensity of the Raman spectrum of each toner particle at the wavenumber λ is normalized to 1, 2750 cm -1 ~3250 cm -1 Let the integrated intensity of the spectrum of each toner particle obtained in the wavenumber region of be I n and the average value of the above I n be I ave When the value calculated by the following (Formula 1) is defined as the CH rate, the number ratio of toner particles with an absolute value of the CH rate of 25.0% or more to all toner particles is 1.0 number % or more and 25.0 number % or less, a magenta toner. CH rate (%) = [(I n - I ave ) / I ave × 100 ··· (Formula 1) (2) The magenta toner according to (1) above, wherein the number ratio of toner particles with an absolute value of the CH rate of 50.0% or more is 3.0 number % or less. (3) The magenta toner according to (1) or (2) above, wherein the number ratio of toner particles with an absolute value of the CH rate of 25.0% or more is 5.0 number % or more and 20.0 number % or less. (4) The magenta toner according to any one of (1) to (3) above, wherein the median value of the CH rate is -3.0% or more. (5) A developer containing the magenta toner according to any one of (1) to (4) above. (6) A toner container unit containing the toner according to any one of (1) to (4) above. (7) An image forming apparatus having an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, developing means for developing the electrostatic latent image to form a visible image using the toner according to any one of (1) to (4) above or the developer according to (5) above, transferring means for transferring the visible image onto a recording medium, and fixing means for fixing the transferred image on the recording medium. (8) An electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, Using the toner according to any one of the above (1) to (4) or the developer according to the above (5), a developing step of developing the electrostatic latent image to form a visible image, A transfer step of transferring the visible image onto a recording medium, An image forming method having a fixing step of fixing the transferred image on the recording medium.

Example

[0196] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples. In the description of the examples, [%] indicates mass%, and "part" indicates "part by mass".

[0197] (Example 1) (Manufacture of Toner 1) -Synthesis of polyester resin- Reaction 1: Into a reaction vessel equipped with a nitrogen introduction tube, a dehydrating tube, a stirrer, and a thermocouple, bisphenol A ethylene oxide 3 mol adduct (EO) and 1,2-propylene glycol (PG) were charged at a molar ratio of 90 / 10, terephthalic acid (TPA) and adipic acid (APA) were charged at a molar ratio of 70 / 30, and OH / COOH = 1.33. It was reacted at 230 °C for 10 hours under normal pressure together with 500 ppm of titanium tetraisopropoxide. Reaction 2: Then, it was reacted for 5 hours under a reduced pressure of 10 mmHg to 15 mmHg. Reaction 3: Then, 10 parts of trimellitic anhydride (TMA) was added to the reaction vessel and reacted at 180 °C under normal pressure for 3 hours to obtain [polyester resin].

[0198] -Synthesis of prepolymer- Into a reaction vessel equipped with a condenser, a stirrer, and a nitrogen introduction tube, 682 parts of bisphenol A ethylene oxide 2 mol adduct, 81 parts of bisphenol A propylene oxide 2 mol adduct, 283 parts of terephthalic acid, 22 parts of trimellitic anhydride, and 2 parts of dibutyltin oxide were added, and reacted at 230 °C for 8 hours under normal pressure, and further reacted for 5 hours under a reduced pressure of 10 mmHg to 15 mmHg to obtain [intermediate polyester resin]. The obtained [intermediate polyester resin] had a number-average molecular weight of 2,100, a weight-average molecular weight of 9,500, a glass transition temperature (Tg) of 55°C, an acid value of 0.5 mg KOH / g, and a hydroxyl value of 51 mg KOH / g. Next, 410 parts of [intermediate polyester resin], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate were placed in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen inlet pipe, and reacted at 100°C for 5 hours to obtain a [prepolymer]. The free isocyanate % of the obtained [prepolymer] was 1.53%.

[0199] - Preparation of release agent dispersion - 70 parts of carnauba wax (WA-05, manufactured by Noda Ceramica Co., Ltd.), 140 parts of [polyester resin], and 290 parts of ethyl acetate were placed in a container equipped with a stirrer and a thermometer, heated to 75°C with stirring, held at 75°C for 1.5 hours, then cooled to 30°C in 1 hour, and dispersed using a bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) under the conditions of a liquid feeding rate of 5 kg / hr, a disk peripheral speed of 6 m / sec, 80% by volume filling of 0.5 mm zirconia beads, and 3 passes to obtain a [release agent dispersion].

[0200] - Preparation of masterbatch - 1,000 parts of water, 1,000 parts of C.I. Pigment Red 269, and 1,000 parts of [polyester resin] were added, mixed using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), the mixture was kneaded at 150°C for 30 minutes using two rolls, then rolled and cooled and pulverized using a pelletizer to obtain [masterbatch 1].

[0201] - Preparation of oil phase 1 - 72 parts of [polyester resin], 113 parts of [release agent dispersion], 68 parts of [masterbatch 1], and 122 parts of ethyl acetate were placed in a container equipped with a thermometer and a stirrer, dispersed using a shear disperser (TK Homomixer) under the condition of a peripheral speed of 12.5 m / sec, and then dispersed using a bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) under the conditions of a liquid feeding rate of 5 kg / hr, a disk peripheral speed of 6 m / sec, 80% by volume filling of 0.5 mm zirconia beads, and 3 passes to obtain [oil phase 1].

[0202] -Manufacture of Aqueous Dispersion of Resin Fine Particles- To a reaction vessel equipped with a stirring rod and a thermometer, 600 parts of water, 120 parts of styrene, 100 parts of methacrylic acid, 45 parts of butyl acrylate, 10 parts of sodium alkyl allyl sulfosuccinate (Ereminol JS-2, manufactured by Sanyo Chemical Industries, Ltd.), and 1 part of ammonium persulfate were charged and stirred at 400 revolutions per minute for 20 minutes, and a white emulsion was obtained. This emulsion was heated to raise the temperature inside the system to 75 °C and reacted for 6 hours. Further, 30 parts of a 1% aqueous ammonium persulfate solution was added and aged at 75 °C for 6 hours to obtain an [aqueous dispersion of resin fine particles]. The volume average particle diameter of the particles contained in this [aqueous dispersion of resin fine particles] was 60 nm, the weight average molecular weight of the resin component was 140,000, and the Tg was 73 °C.

[0203] -Preparation of Aqueous Phase- 990 parts of water, 83 parts of [aqueous dispersion of resin fine particles], 37 parts of a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Ereminol MON-7, manufactured by Sanyo Chemical Industries, Ltd.), and 90 parts of ethyl acetate were mixed and stirred to obtain an [aqueous phase].

[0204] -Emulsification or Dispersion- To 374 parts of the above [oil phase 1], 77 parts of an ethyl acetate solution of [prepolymer] and 2.5 parts of a 50% ethyl acetate solution of isophoronediamine were added, and stirred with a TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at a rotation speed of 5,000 rpm to be uniformly dissolved and dispersed to obtain an [oil phase 1']. Next, 550 parts of the [aqueous phase] was placed in another container equipped with a stirrer and a thermometer, and while stirring with a TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 11,000 rpm, the [oil phase 1'] was added and emulsified for 1 minute to obtain an [emulsion slurry 1].

[0205] -Desolventization ~ Washing ~ Drying- The [emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and desolventized at 30 °C for 8 hours under reduced pressure to obtain a [slurry 1]. After holding the obtained [slurry 1] at 45 °C for 2 hours, it was filtered under reduced pressure, and the following washing treatment was performed. (1) 100 parts of ion-exchanged water was added to the filter cake and mixed with a TK homomixer (at a rotation speed of 6,000 rpm for 5 minutes), and then filtered. (2) 100 parts of ion-exchanged water was added to the filter cake of (1) and mixed with a TK homomixer (at a rotation speed of 6,000 rpm for 5 minutes). Then, 1% hydrochloric acid was added with stirring until the pH reached about 3.3, and stirring was continued for 1 hour in that state, followed by filtration. (3) 300 parts of ion-exchanged water was added to the filter cake of (2) and mixed with a TK homomixer (at a rotation speed of 6,000 rpm for 5 minutes), and then the filtration operation was performed twice to obtain Filter Cake 1.

[0206] The obtained Filter Cake 1 was dried in a circulating air dryer at 40 °C for 48 hours. Then, it was sieved with a 75 μm mesh sieve to prepare [Toner Matrix Particles 1].

[0207] -Mixing- To the above [Toner Matrix Particles 1], 1.5 parts of hydrophobic silica (HDK-2000, manufactured by Wacker Chemie AG) was added per 100 parts of the mother particles, and mixed with a 20 L Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) at a peripheral speed of 33 m / s for 5 minutes. The above was air-sieved through a 500 mesh sieve to obtain [Toner 1].

[0208] (Example 2) In the preparation of [Oil Phase 1] in Example 1, [Toner 2] was prepared in the same manner as in Example 1 except that the disk peripheral speed of the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was changed to 8 m / sec.

[0209] (Example 3) In the preparation of [Oil Phase 1] in Example 1, [Toner 3] was prepared in the same manner as in Example 1 except that the disk peripheral speed of the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was changed to 9 m / sec.

[0210] (Example 4) In the preparation of [oil phase 1] in Example 1, [toner 4] was prepared in the same manner as in Example 1, except that the disk peripheral speed of the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was changed to 10 m / sec.

[0211] (Example 5) In the preparation of [oil phase 1] in Example 4, [toner 5] was prepared in the same manner as in Example 4, except that the peripheral speed of the shear disperser was changed to 13.5 m / sec for pre-dispersion.

[0212] (Example 6) In the preparation of [oil phase 1] in Example 5, [toner 6] was prepared in the same manner as in Example 5, except that the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was filled with 80% by volume of 0.3 mm zirconia beads.

[0213] (Example 7) -Preparation of layered inorganic mineral masterbatch- 100 parts of [polyester resin], 100 parts of a montmorillonite compound (Cloisite APA, manufactured by Southern Clay Products, Inc., particle size 500 nm) modified with a quaternary ammonium salt having a benzyl group in at least a part thereof, and 50 parts of ion-exchanged water were thoroughly mixed and kneaded with an open roll type kneader (manufactured by Nidex / Mitsui Mining Co., Ltd.). The kneading was started at 90°C and then gradually cooled to 50°C to prepare [layered inorganic mineral masterbatch 1] in which the ratio (mass ratio) of the resin to the layered inorganic mineral was 1:1. In the preparation of [oil phase 1] in Example 6, [toner 7] was prepared in the same manner as in Example 6, except that 1.6 parts out of 72 parts of [polyester resin] were replaced with [layered inorganic mineral masterbatch 1].

[0214] (Example 8) In the preparation of [oil phase 1] in Example 6, [toner 8] was prepared in the same manner as in Example 6, except that 0.8 parts out of 72 parts of [polyester resin] were replaced with [layered inorganic mineral masterbatch 1].

[0215] (Example 9) In the preparation of [Oil Phase 1] in Example 8, [Toner 9] was prepared in the same manner as in Example 8, except that the disk peripheral speed of the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was changed to 12 m / sec.

[0216] (Example 10) In the preparation of [Oil Phase 1] in Example 9, [Toner 10] was prepared in the same manner as in Example 8, except that the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was filled with 80% by volume of 0.2 mm zirconia beads.

[0217] (Example 11) In the preparation of [Oil Phase 1] in Example 10, [Toner 11] was prepared in the same manner as in Example 8, except that the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was filled with 80% by volume of 0.1 mm zirconia beads.

[0218] (Comparative Example 1) In the preparation of [Oil Phase 1] in Example 5, [Toner 12] was prepared in the same manner as in Example 5, except that dispersion using a bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was not performed.

[0219] (Comparative Example 2) In the preparation of [Oil Phase 1] in Example 8, [Toner 13] was prepared in the same manner as in Example 8, except that the disk peripheral speed of the bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) was changed to 13 m / sec.

[0220] (Comparative Example 3) In the preparation of [Oil Phase 1] in Example 11, [Toner 14] was prepared in the same manner as in Example 9, except that dispersion was performed by changing the peripheral speed of the shear disperser to 10.0 m / sec.

[0221] (Comparative Example 4) In Comparative Example 1, in addition to the hydrophobic silica, 1.5 parts of titanium oxide surface-modified by zinc ion treatment was added to [toner base particles 1], and [toner 15] was produced in the same manner as in Comparative Example 1 except that it was mixed at a peripheral speed of 33 m / s for 5 minutes using a 20 L Henschel mixer (manufactured by Mitsui Mining Co., Ltd.).

[0222] (Comparative Example 5) In Comparative Example 1, after obtaining [toner base particles 1], [toner 16] was produced in the same manner as in Comparative Example 1 except that classification was performed using an air classifier "DS5 type" (manufactured by Nippon Pneumatic Mfg. Co., Ltd.).

[0223] (Comparative Example 6) In Comparative Example 1, 300 parts of ion-exchanged water was added to the filtered cake after washing, mixed with a TK homomixer (at a rotation speed of 6,000 rpm for 5 minutes), and then [toner 17] was produced in the same manner as in Comparative Example 1 except that a spheroidizing heat treatment was performed at 55 °C for 1 hour.

[0224] The production conditions, etc. of the toners obtained as described above are shown in Table 1.

Table 1

[0225] (Measurement) For the toners obtained in the above Examples and Comparative Examples, the following measurements were performed.

[0226] <CH rate measurement> Using a Raman microscope "XploRA PLUS" (manufactured by Horiba, Ltd.), Raman spectra of 500 to 600 or more particles per toner particle were measured for each toner particle using a laser with an excitation wavelength of 785 nm. The CH rate was calculated from the Raman spectra, and the ratio of particles with a CH rate of 25.0% or more, the ratio of particles with a CH rate of 50.0% or more, and the median value of the CH rate were determined. The results are shown in Table 2.

[0227] <Fluorescent X-ray elemental analysis (XRF)> (Quantification of layered inorganic minerals in toner) The addition amount of the layered inorganic mineral was quantified by X-ray fluorescence. For the calibration curve, toner with a predetermined amount of the layered inorganic mineral added thereto in advance was prepared, and Al contained in the layered inorganic mineral was measured to obtain the calibration curve. For sample preparation, 3 g of the toner obtained after drying was pellet-molded into a diameter of 3 mm and a thickness of 2 mm using an automatic pressure molding machine (manufactured by Maekawa, model T-BRB-32) with a load of 6.0 t and a pressure application time of 60 sec (manufacturer and conditions). Al in the toner was measured by quantitative analysis using an X-ray fluorescence apparatus (ZSX-100e, manufactured by Rigaku Corporation), and the content ratio of the layered inorganic mineral was calculated as mass% from the prepared calibration curve. The measurement results are shown in Table 2.

[0228] <Measurement of charge amount distribution> The charge amount (μC / g) of the toner was measured using a blow-off powder charge amount measuring device TB-200 (manufactured by Kyocera). The charge amount distribution was measured by measuring the Q / d distribution (fC / μm) using a charge amount distribution measuring device Easpart Analyzer (manufactured by Hosokawa Micron), and the particle ratio in the positive charge region was calculated as the WST rate. The results are shown in Table 2.

[0229] <Measurement of particle size distribution> The particle size distribution of the toner was measured using a Coulter Multisizer III (manufactured by Coulter, trade name). A personal computer (manufactured by IBM) was connected, and the ratio (Dv / Dn) was obtained from the volume-based weight average particle diameter (Dv) and the number average particle diameter (Dn) obtained from the number distribution using dedicated analysis software (manufactured by Coulter). The results are shown in Table 2.

[0230] <Measurement of shape distribution> Using a flow-type particle image analyzer FPIA-3000 (manufactured by Sysmex, trade name), the average circularity of 3000 or more particles was measured, and the number ratio of particles with a circularity of 0.850 or less among the measured particles was determined.

[0231]

Table 2

[0232] <Preparation of Developer 1> 5 parts of the above [Toner 1] and 95 parts of the carrier described below were mixed using a Turbler Shaker Mixer (manufactured by Shinmaru Enterprises Co., Ltd.) to obtain [Developer 1]. - Preparation of Carrier - 100 parts of silicone resin (organostraight silicone) 100 parts of toluene 5 parts of γ-(2-aminoethyl)aminopropyltrimethoxysilane 10 parts of carbon black The above mixture was dispersed using a homomixer for 20 minutes to prepare a coating layer forming liquid. This coating layer forming liquid was coated on the surface of 1000 parts of spherical magnetite with a particle size of 50 μm using a fluidized bed type coating apparatus to obtain a magnetic carrier. Using an image forming apparatus using [Developer 1] containing [Toner 1], the transferability, resistance to in-machine contamination, and cleaning property of the image were evaluated by the evaluation method described below.

[0233] <Preparation of Developers 2 to 17> In the preparation of [Developer 1], [Developers 2] to [Developer 17] were obtained in the same manner as the preparation of Developer 1, except that [Toner 1] was replaced with [Toner 2] to [Toner 17].

[0234] [Evaluation of Transferability] Using a copier (Imagio MP 7501) evaluation machine manufactured by Ricoh Company, Ltd. with a line speed tuned to 162 mm / sec and a transfer time tuned to 40 msec, for the above [Developer 1] to [Developer 17], an A4 size, solid pattern with a toner adhesion amount of 0.6 mg / cm 2 was used as a test image to conduct a running test for output. For the initial and after 100K output of the test image, the transfer efficiency in primary transfer was determined by the following (Formula 2), and the transfer efficiency in secondary transfer was determined by the following (Formula 3). The evaluation criteria are as follows. Primary transfer efficiency (%) = (amount of toner transferred onto the intermediate transfer body / amount of toner developed on the electrophotographic photoreceptor) × 100 ··· (Formula 2) Secondary transfer efficiency (%) = [(toner amount transferred onto the intermediate transfer medium - residual toner amount remaining on the intermediate transfer medium) / toner amount transferred onto the intermediate transfer medium] × 100... (Equation 3)

[0235] - Evaluation criteria - The evaluation criteria were calculated by multiplying the primary transfer rate and the secondary transfer rate and evaluated according to the following criteria. Rank: Transfer rate 10: 99.0% or more 9: 98.0% or more and less than 99.0% 8: 96.0% or more and less than 98.0% 7: 94.0% or more and less than 96.0% 6: 92.0% or more and less than 94.0% 5: 90.0% or more and less than 92.0% 4: 88.0% or more and less than 90.0% 3: 86.0% or more and less than 88.0% 2: 84.0% or more and less than 86.0% 1: Less than 84.0%

[0236] [Evaluation of resistance to in-machine contamination] The [developer 1] of the above example was placed in a Ricoh digital color imagio Neo C600 retrofit machine for evaluation. After printing 100,000 image charts with a 50% image area in monochrome mode, the stains around the printed matter and the fixing and paper discharge parts were visually observed and evaluated by comparing them with a 10-step (R1 - R10) step sample. Note that the stains around the printed matter and the fixing and paper discharge parts mean that the stains are more serious in ascending order of rank. The evaluation of R1 shows stains at an unacceptable level both around the fixing part and on the printed matter, and it is at a level where it cannot be adopted as a product.

[0237] [Evaluation of blade cleanability] The blade cleaning property was evaluated using a color copier (Ipsio Color8100; manufactured by Ricoh Company, Ltd.) loaded with the developer and the electrostatic latent image carrier (electrophotographic photoreceptor, photoreceptor). After running 100,000 sheets using 6,000 sheets of paper (manufactured by Ricoh Company, Ltd.) at a printing rate of 7% image occupancy rate, 10 consecutive images with an image occupancy rate of 50% were output in an environment of 10°C and 15% RH, and the 10th image was stopped during development. At this time, the toner on the drum before and after the cleaning blade on the photoreceptor was tape-transferred respectively. The ID measurement was performed using X-Rite eXact (X-Rite) on the tape transferred to 6,000 sheets of paper, and the cleaning rate was obtained from the ID by the following formula (4). Cleaning rate [%] = ΔID (remaining ID after transfer - ID after cleaning) / remaining ID after transfer ··· (Formula 4)

[0238] - Evaluation criteria - Rank: Cleaning rate 5: 80% or more 4: 60% or more and less than 80% 3: 40% or more and less than 60% 2: 20% or more and less than 40% 1: Less than 20% Note that 2 is equivalent to the conventional product, and 1 is a level that cannot be adopted as a product.

[0239] <Overall judgment> The evaluation criteria for the overall judgment are as follows. All ranks were added together to obtain the total rank score, and the toner was evaluated in five levels from the total rank score. “☆” means extremely good, “◎” means very good, “〇” means good, “△” means equivalent to the conventional product, and “×” means a level that cannot be used in practice. “☆”, “◎”, “〇” were regarded as passing, and “△”, “×” were regarded as failing. In addition, for those with a blade cleaning property rank of “1”, the overall judgment was “×” regardless of the total rank score. Overall judgment: Total rank score ☆☆: 23 or more ☆: 18 or more and 22 or less ◎: 14 or more and 17 or less 〇: 13 △: 12 or less ×: Blade cleaning rank is 1

[0240] The results obtained above are shown in Table 3.

Table 3

[0241] As is clear from the evaluation results in Table 3, for Examples 1 to 11, the transferability, resistance to in-machine contamination, and cleaning performance are all achieved at a high level. On the other hand, for Comparative Examples 1 to 6, any one of the transfer rate, resistance to in-machine contamination, and cleaning performance is at a low level, or the result of one of them has a practical problem.

Explanation of symbols

[0242] 10 Electrostatic latent image carrier (photoconductor drum) 10K Electrostatic latent image carrier for black 10Y Electrostatic latent image carrier for yellow 10M Electrostatic latent image carrier for magenta 10C Electrostatic latent image carrier for cyan 14 Support roller 15 Support roller 16 Support roller 17 Intermediate transfer cleaning device 18K, 18Y, 18M, 18C Image forming unit 20 Charging roller 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressing roller 28 Sheet reversing device 30 Exposure device 32 Contact glass 33 First running body 34 Second running body 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42K Developing agent storage section 42Y Developing agent storage section 42M Developing agent storage section 42C Developing agent storage section 43K Developing agent supply roller 43Y Developing agent supply roller 43M Developing agent supply roller 43C Developing agent supply roller 44K Developing roller 44Y Developing roller 44M Developing roller 44C Developing roller 45K Black developing unit 45Y Yellow developing unit 45M Magenta developing unit 45C Cyan developing unit 49 Resist roller 50 Intermediate transfer belt 51 Roller 52 Separation roller 53 Manual paper feed path 54 Manual paper feed tray 55 Switching claw 56 Discharge roller 57 Discharge tray 58 Corona charging device 60 Cleaning device 61 Developing device 62 Transfer roller 63 Photoconductor cleaning device 64 Charge removal lamp 70 Charge removal lamp 80 Transfer roller 90 Cleaning device 95 Transfer paper 100A, 100B, 100C Image forming device 120 Image forming unit 130 Document table 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separation roller 146 Paper feed path 147 Conveyor roller 148 Paper feed path 150 Copier main body 160 Charging device 200 Paper feed table 300 Scanner 400 Automatic document feeder (ADF)

Prior art documents

Patent documents

[0243]

Patent Document 1

Patent Document 2

Patent Document 3

Claims

1. A magenta toner containing at least a binder resin and a colorant, wherein the colorant includes a magenta coloring pigment, the binder resin includes a polyester resin, toner mother particles are granulated in an aqueous medium, the average circularity of the toner is 0.960 to 0.980, The intensity of each toner particle in the Raman spectrum of the magenta toner at a wavenumber λ at which the total intensity obtained by adding the Raman spectra of each toner particle in the wavenumber range of 1200 cm －１ to 3250 cm －１ shows a maximum value. When the intensity of the Raman spectrum of each toner particle is normalized to 1, the integrated intensity of the spectrum of each toner particle in the wavenumber range of 2750 cm －１ to 3250 cm －１ is defined as I ｎ . When the average value of the above I ｎ is defined as I ａｖｅ , and the value calculated by the following (Equation 1) is defined as the CH ratio, a magenta toner in which the percentage of the number of toner particles having an absolute value of the CH ratio of 25.0% or more with respect to all toner particles is 1.0% by number or more and 25.0% by number or less. CH rate (%) = [(I ｎ - I ａｖｅ ) / I ａｖｅ × 100... (Equation 1)

2. The magenta toner according to claim 1, wherein the number ratio of toner particles having an absolute value of the CH rate of 50.0% or more to all toner particles is 3.0% or less.

3. The magenta toner according to claim 1 or 2, wherein the volume-based weight average particle diameter (Dv) of the magenta toner is 3 μm to 7 μm, and the ratio (Dv / Dn) of the volume-based weight average particle diameter (Dv) to the number average particle diameter (Dn) is 1.00 to 1.

25.

4. The magenta toner according to any one of claims 1 to 3, wherein the median value of the CH rate is -3.0% or more.

5. A toner container unit containing a developer containing the magenta toner according to any one of claims 1 to 4.

6. An electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, developing means for developing the electrostatic latent image to form a visible image using the toner according to any one of claims 1 to 4, transfer means for transferring the visible image onto a recording medium, An image forming apparatus having fixing means for fixing the transferred image on the recording medium.

7. An electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image to form a visible image using the toner according to any one of claims 1 to 4, a transfer step of transferring the visible image onto a recording medium, An image forming method having a fixing step of fixing the transferred image on the recording medium.

8. A method for manufacturing a magenta toner containing at least a binder resin and a colorant, a masterbatch forming step of kneading a mixture of the colorant and the binder resin with a shear disperser, a step of preparing an oil phase by dispersing the masterbatch and the binder resin in a solvent with a mill and a shear disperser, a step of granulating toner mother particles in an aqueous medium, a step of externally adding an external additive to the toner mother particles, including, wherein the colorant includes a magenta coloring pigment, the binder resin includes a polyester resin, the average circularity of the toner is 0.960 to 0.980, ​ When the intensity of the Raman spectrum of each toner particle at the wavenumber λ at which the total intensity obtained by adding up the Raman spectra of each toner particle in the wavenumber range of 1200 cm －１ to 3250 cm －１ shows the maximum value is normalized to 1, when the integrated intensity of the spectrum of each toner particle in the wavenumber range of 2750 cm －１ to 3250 cm －１ is defined as I ｎ and the average value of the above I ｎ is defined as I ａｖｅ and the value calculated by the following (Formula 1) is defined as the CH ratio, a method for manufacturing a magenta toner in which the percentage by number of toner particles having an absolute value of the CH ratio of 25.0% or more with respect to all toner particles is 1.0% by number or more and 25.0% by number or less. CH rate (%) = [(I ｎ - I ａｖｅ ) / I ａｖｅ × 100... (Equation 1)

Images