Toner

Abstract

The present invention relates to a toner. A toner comprising toner particles, wherein the toner particles comprise core particles containing a binder resin and a surface layer containing inorganic fine particles and an organic silicon polymer, wherein the organic silicon polymer has a structure composed of R-Si(O 1 / 2 )3 represents the T3 structure, in the THF insoluble matter of the toner particles 29 In Si-NMR measurement, the ratio of the peak area attributable to the T3 structure relative to the total peak area of ​​the silicone polymer is at least 5.0%, and in observation of a cross section of the toner particle using TEM, the toner has a predetermined surface layer thickness, a predetermined number of inorganic fine particles in contact with the core particle in the surface layer, and a predetermined number of inorganic fine particles present in the core particle and not in contact with the surface layer.

Description

Technical Field

[0001] The present disclosure relates to a toner for use in an image forming method such as electrophotography. Background Art

[0002] In recent years, electrophotographic image forming apparatuses have been increasingly demanded for higher speeds, longer lifespans, greater energy savings, and smaller size. In response to these demands, further improvements in various toner properties are also being sought. In response to these demands, toner within the developing device is subject to increased exposure to stresses such as heat and impact. Consequently, in order to maintain good image quality regardless of the operating environment, even during the output of multiple images, there is a need for highly durable toners that can maintain high levels of charging performance and durability.

[0003] On the other hand, in terms of energy conservation, toners showing excellent low-temperature fixability are required, although this generally involves a trade-off with high durability. As a result, there is a greater demand for toners capable of showing both high durability and low-temperature fixability at high levels.

[0004] One means for solving this problem is a method of covering the surface of toner particles with a resin.

[0005] As a method of covering the surface of toner particles with a silicon compound, Japanese Patent Application Laid-Open No. H03-089361 describes a method of producing a polymerized toner in which a silane coupling agent is added to a reaction system.

[0006] Japanese Patent Application Laid-Open No. H09-179341 describes a polymerized toner having a coating film on the surface of a reaction product derived from a radically polymerizable organosilane compound. Summary of the Invention

[0007] Research conducted by the present inventors has revealed that the toner described in Japanese Patent Application Laid-Open No. H03-089361 has insufficient silane compound deposition on the toner surface, leaving room for improvement in achieving both low-temperature fixability and high durability required for high-speed and long-life applications. The toner described in Japanese Patent Application Laid-Open No. H09-179341 has an organic functional group with high polarity, insufficient silane compound deposition on the toner particle surface, insufficient hydrolysis and polycondensation of the silane compound, and a weak degree of crosslinking. Consequently, this is insufficient for achieving both low-temperature fixability and high durability required for high-speed and long-life applications, and leaves room for improvement.

[0008] The present disclosure provides a toner that exhibits low-temperature fixing ability and high durability even when an image forming apparatus is operated at a higher speed and has a longer life.

[0009] As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the problems can be solved by the toner described below.

[0010] The present disclosure relates to a toner comprising toner particles, wherein the toner particles include

[0011] core particles containing a binder resin, and

[0012] A surface layer containing inorganic fine particles and an organosilicon polymer, wherein

[0013] The organosilicon polymer has a structure given by the following formula (T3):

[0014] R-Si(O 1 / 2 )3 (T3)

[0015] wherein R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group;

[0016] THF-insoluble matter in toner particles 29 In Si-NMR measurement, the ratio of the peak area attributable to the structure given by formula (T3) relative to the total peak area of ​​the organosilicon polymer is at least 5.0%; and

[0017] In observation of a cross section of toner particles using a transmission electron microscope,

[0018] The major axis L is a chord passing through the geometric center of the toner particle and having the longest diameter in the cross section of the toner particle,

[0019] Line segment a is one of the line segments when the major axis L is divided at its midpoint.

[0020] Arn (n=1 to 32) are 32 line segments drawn from the midpoint of the major axis L to the surface of the toner particle with the line segment a as the reference and shifted by 11.25° at a time.

[0021] RAn (n=1 to 32) is the length of each line segment, and

[0022] FRAn (n=1 to 32) is the thickness of the surface layer on Arn (n=1 to 32),

[0023] In the cross section of the toner particles within the range of ±10% of the weight average particle size of the toner particles, Dtem defined by the following formula (1) is:

[0024] (i) the average thickness Dav. of the surface layer is 5.0 to 100.0 nm,

[0025] (ii) the proportion of Arn line segments with FRAn not exceeding 5.0 nm does not exceed 20.0%,

[0026] (iii) the number of inorganic fine particles in contact with the core particle in the surface layer is 16 to 30 per 1 toner particle, and

[0027] (iv) Among 100 toner particles having a Dtem within the range of ±10% of the weight-average particle diameter of the toner particles, the proportion of toner particles containing at least one inorganic fine particle that is present in the core particle and is not in contact with the surface layer is not more than 10%;

[0028] Dtem=(RA1+RA2+RA3+RA4+RA5+RA6+RA7+RA8+RA9+RA10+RA11+RA12+RA13+RA14+RA15+RA16+RA1 7+RA18+RA19+RA20+RA21+RA22+RA23+RA24+RA25+RA26+RA27+RA28+RA29+RA30+RA31+RA32) / 16 (1).

[0029] The present disclosure can thus provide a toner that exhibits stable charging performance and high durability even when the speed of an image forming apparatus is increased and the life of the apparatus is extended.

[0030] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is an example of a schematic structural diagram of an image forming apparatus;

[0032] Figure 2 is an example of an image of a cross section of a toner particle as observed using a transmission electron microscope; and

[0033] Figure 3 THF insoluble matter of toner particles 29 Example of Si-NMR measurement. DETAILED DESCRIPTION

[0034] The present disclosure is described in detail below. The reference numerals used in the drawings are defined as follows.

[0035] 11 Photosensitive member, 12 Developing roller, 13 Toner supply roller, 14 Toner, 15 Regulating blade, 16 Developing device, 17 Laser, 18 Charging device, 19 Cleaning device, 20 Cleaning charging device, 21 Stirring blade, 22 Drive roller, 23 Transfer roller, 24 Bias power supply, 25 Tension roller, 26 Transfer conveyor belt, 27 Driven roller, 28 Paper, 29 Paper supply roller, 30 Adsorption roller, 31 Fixing device

[0036] The present disclosure relates to a toner comprising toner particles, wherein the toner particles include

[0037] core particles containing a binder resin, and

[0038] A surface layer containing inorganic fine particles and an organosilicon polymer, wherein

[0039] The organosilicon polymer has a structure given by the following formula (T3):

[0040] R-Si(O 1 / 2 )3 (T3)

[0041] wherein R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group;

[0042] THF-insoluble matter in toner particles 29 In Si-NMR measurement, the ratio of the peak area attributable to the structure given by formula (T3) relative to the total peak area of ​​the organosilicon polymer is at least 5.0%; and

[0043] In observation of a cross section of toner particles using a transmission electron microscope,

[0044] The major axis L is a chord passing through the geometric center of the toner particle and having the longest diameter in the cross section of the toner particle,

[0045] Line segment a is one of the line segments when the major axis L is divided at its midpoint.

[0046] Arn (n=1 to 32) are 32 line segments drawn from the midpoint of the major axis L to the surface of the toner particle with the line segment a as the reference and shifted by 11.25° at a time.

[0047] RAn (n=1 to 32) is the length of each line segment, and

[0048] FRAn (n=1 to 32) is the thickness of the surface layer on Arn (n=1 to 32),

[0049] In the cross section of the toner particles within the range of ±10% of the weight average particle size of the toner particles, Dtem defined by the following formula (1) is:

[0050] (i) the average thickness Dav. of the surface layer is 5.0 to 100.0 nm,

[0051] (ii) the proportion of Arn line segments with FRAn not exceeding 5.0 nm does not exceed 20.0%,

[0052] (iii) the number of inorganic fine particles in contact with the core particle in the surface layer is 16 to 30 per 1 toner particle, and

[0053] (iv) Among 100 toner particles having a Dtem within the range of ±10% of the weight-average particle diameter of the toner particles, the proportion of toner particles containing at least one inorganic fine particle that is present in the core particle and is not in contact with the surface layer is not more than 10%;

[0054] Dtem=(RA1+RA2+RA3+RA4+RA5+RA6+RA7+RA8+RA9+RA10+RA11+RA12+RA13+RA14+RA15+RA16+RA1 7+RA18+RA19+RA20+RA21+RA22+RA23+RA24+RA25+RA26+RA27+RA28+RA29+RA30+RA31+RA32) / 16 (1).

[0055] The present inventors believe that the following are the reasons why the effects of the present disclosure are obtained when specified conditions are satisfied.

[0056] The toner particles have a surface layer comprising inorganic fine particles and an organic silicon polymer, and the organic silicon polymer has a 3 / 2 (The structure given by Formula (T3)).

[0057] R in the formula represents an alkyl group having 1 to 6 carbons (preferably 1 to 4 carbons and more preferably 1 or 2 carbons), or a phenyl group.

[0058] In the structure given by formula (T3), one of the four valences of the silicon atom is bonded to the organic group represented by R and the remaining three are bonded to oxygen atoms. The oxygen atoms are in a state where both of their valences are bonded to silicon atoms, i.e., a siloxane bond (Si-O-Si). When considering silicon atoms and oxygen atoms in the form of an organosilicon polymer, since there are three oxygen atoms for two silicon atoms, -SiO is used. 3 / 2 That is, the structure represented by formula (T3) is a structure as given by the following formula.

[0059]

[0060] The-SiO 3 / 2 The structure is similar to silicon dioxide (SiO2) composed of a large number of siloxane structures, and since it has a hardness similar to that of silicon dioxide, the inventors believe that by 3 / 2 The structure is introduced into the organosilicon polymer in the surface layer of the toner particles to achieve high durability.

[0061] In addition, the tetrahydrofuran-insoluble matter (hereinafter also referred to as THF-insoluble matter) of the toner particles 29In Si-NMR measurement, the ratio of the peak area attributable to the structure given by formula (T3) relative to the total peak area of ​​the organic silicon polymer is at least 5.0%. Although the details of the measurement method are given below, this approximately means that, among the organic silicon polymers contained in the surface layer of the toner particles, the peak area attributable to the structure given by R-SiO 3 / 2 The proportion of silicon atoms in the given structure is at least 5.0% of all silicon atoms in the organosilicon polymer.

[0062] As mentioned above, R-SiO 3 / 2 The meaning of the given structure is that, of the four valences of the silicon atom, three are bonded to oxygen atoms and these oxygen atoms are bonded to different silicon atoms. When one of these oxygen atoms constitutes a silanol group, then the structure consists of R-SiO 2 / 2 -OH. This structure is similar to that of disubstituted silicone resins represented by dimethyl silicone.

[0063] Therefore, it is believed that as more R-SiO 3 / 2 Given the structure, the surface layer of the toner particle begins to show hardness properties like silica as described above and can show high durability. On the other hand, when there is less R-SiO 3 / 2 When the structure is, for example, with the R-SiO 2 / 2 As the structure represented by -OH increases, organic properties become dominant and durability decreases, whereas as the structure given by SiO2 becomes more, hardness properties like silica become dominant and fixing performance decreases.

[0064] As a result, the silicone polymer must have at least 5.0% of the R-SiO 3 / 2 The structure given by formula (T3) must be present. That is, the ratio of the peak area attributable to the structure given by formula (T3) relative to the total peak area of ​​the organosilicon polymer must be at least 5.0%. This peak area ratio can be, for example, not more than 85.0%.

[0065] From the viewpoint of high durability, the ratio of the peak area attributable to the structure having formula (T3) relative to the total peak area of ​​the silicone polymer is preferably 20.0% to 85.0%, more preferably 40.0% to 80.0%, and even more preferably 40.0% to 67.5%. The ratio of the peak area of ​​the structure given by formula (T3) can be controlled by the reaction temperature during the formation of the structure having formula (T3) and the pH during the reaction.

[0066] Furthermore, in observation of a cross section of toner particles using a transmission electron microscope (hereinafter also referred to as TEM),

[0067] The major axis L is a chord passing through the geometric center of the toner particle and having the longest diameter in the cross section of the toner particle,

[0068] Line segment a is one of the line segments when the major axis L is divided at its midpoint.

[0069] Arn (n=1 to 32) are 32 line segments drawn from the midpoint of the major axis L to the surface of the toner particle with the line segment a as the reference and shifted by 11.25° at a time.

[0070] RAn (n=1 to 32) is the length of each line segment, and

[0071] FRAn (n=1 to 32) is the thickness of the surface layer on Arn (n=1 to 32),

[0072] High levels of durability and fixing performance can be achieved by making the average thickness Dav. of the surface layer in the cross section of the toner particles within the range of ±10% of the toner particle weight average particle diameter Dtem defined by the following formula (1) 5.0 nm to 100.0 nm.

[0073] Dtem=(RA1+RA2+RA3+RA4+RA5+RA6+RA7+RA8+RA9+RA10+RA11+RA12+RA13+RA14+RA15+RA16+RA1 7+RA18+RA19+RA20+RA21+RA22+RA23+RA24+RA25+RA26+RA27+RA28+RA29+RA30+RA31+RA32) / 16 (1)

[0074] When Dav. is less than 5.0 nm, durability is reduced, while when Dav. exceeds 100.0 nm, fixing performance is reduced. Dav. is preferably 10.0 nm to 70.0 nm and more preferably 10.0 nm to 50.0 nm. The average thickness Dav. of the surface layer of the organosilicon polymer can be controlled by, for example, the content of the organosilicon polymer, the ratio of hydrophilic groups to hydrophobic groups in the organosilicon polymer, and the reaction temperature, reaction time, reaction medium, and pH during hydrolysis, addition polymerization, and polycondensation.

[0075] In addition, a highly durable toner capable of withstanding stress within a developing device can be obtained by ensuring that the proportion of Arn line segments with a FRAn of no more than 5.0 nm in a cross section of a toner particle within the range of ±10% of the weight-average particle diameter of the toner particle does not exceed 20.0%. When the proportion of Arn line segments with a FRAn of no more than 5.0 nm exceeds 20.0%, the durability of the toner decreases, filming occurs on the surface of the developing roller, and uneven shading occurs. The proportion of Arn line segments with a FRAn of no more than 5.0 nm is preferably no more than 10.0% and more preferably no more than 5.0%. The proportion of Arn line segments with a FRAn of no more than 5.0 nm is preferably as low as possible and is, for example, at least 0.0%. Any combination of these numerical ranges may be used.

[0076] The proportion of Arn segments with FRAn not exceeding 5.0 nm can be controlled by, for example, the content of the organosilicon polymer, the ratio of hydrophilic groups to hydrophobic groups in the organosilicon polymer, and the reaction temperature, reaction time, reaction medium and pH during hydrolysis, addition polymerization and condensation polymerization.

[0077] However, R-SiO 3 / 2 The presence of an organosilicon polymer with a structure in the surface layer of toner particles has raised concerns about its effect on fixing performance. As a result of intensive research, the present inventors have discovered that coexistence with fixing performance can be achieved by limiting the number of inorganic fine particles in contact with the core particles in the surface layer to 16 to 30 per toner particle.

[0078] Inorganic fine particles generally exhibit hardness, and as a result, it is believed that when they are contained in toner particles, the inorganic fine particles may reduce fixing performance. However, by satisfying the specified conditions, it is believed that during fixing, the inorganic fine particles destroy the surface layer and contribute to the melting of the toner, thereby providing support for excellent fixing performance.

[0079] When the number of inorganic fine particles is less than 16, the surface layer cannot be sufficiently destroyed, thereby reducing the fixing performance. When the number of inorganic fine particles exceeds 30, the charging performance of the toner is eventually reduced and fogging occurs. The number of inorganic fine particles is preferably 19 to 29 and more preferably 20 to 24.

[0080] The amount of the inorganic fine particles in contact with the core particles in the surface layer can be controlled using, for example, the amount of inorganic fine particles serving as a dispersion stabilizer supplementally added during the granulation step.

[0081] Furthermore, among 100 toner particles having a Dtem within the range of ±10% of the weight-average particle diameter of the toner particles, the proportion of toner particles having at least one inorganic fine particle present in the core particle and not in contact with the surface layer must not exceed 10%. When the proportion of toner particles having inorganic fine particles present in the core particle and not in contact with the surface layer exceeds 10%, this causes a decrease in fixing performance as described above. The proportion of such toner particles is preferably no more than 5% and more preferably no more than 2%. The proportion of such toner particles is preferably as low as possible, and for example, is at least 0%. Any combination of these numerical ranges may be used.

[0082] The ratio of the toner particles having at least one inorganic fine particle present in the core particle and not in contact with the surface layer can be controlled by, for example, the amount of inorganic fine particles serving as a dispersion stabilizer supplementally added during the granulation step.

[0083] As the inorganic fine particles, known inorganic fine particles can be used without particular limitation, but the inorganic fine particles preferably contain at least one selected from the group consisting of a calcium element and a magnesium element, and containing a calcium element is more preferred.

[0084] The content of at least one selected from the group consisting of calcium element and magnesium element (preferably calcium element) in the inorganic fine particles is preferably 50% by mass to 100% by mass and more preferably 85% by mass to 100% by mass.

[0085] Using Dm as the number average particle size of the primary particle size of the inorganic fine particles, Dm is preferably 50.0 nm to 800.0 nm. By setting Dm to at least 50.0 nm, the destruction of the surface layer during fixing is promoted and a tendency for further improvement in fixing performance is established. By setting Dm to no more than 800.0 nm, the influence on the toner charging performance can be suppressed and a tendency for further suppression of fogging is established. Dm is more preferably 90.0 nm to 200.0 nm. This Dm can be controlled, for example, by the temperature and agitator rotation speed during the preparation of the inorganic fine particles used as a dispersion stabilizer.

[0086] In TEM observation of the cross section of the colorant particles, among 100 colorant particles whose Dtem is within the range of ±10% of the weight-average particle size of the colorant particles, the proportion of colorant particles in which at least one inorganic fine particle exists in each of the area of ​​the surface layer sandwiched between Ar1 and Ar5, the area of ​​the surface layer sandwiched between Ar5 and Ar9, the area of ​​the surface layer sandwiched between Ar9 and Ar13, the area of ​​the surface layer sandwiched between Ar13 and Ar17, the area of ​​the surface layer sandwiched between Ar17 and Ar21, the area of ​​the surface layer sandwiched between Ar21 and Ar25, the area of ​​the surface layer sandwiched between Ar25 and Ar29, and the area of ​​the surface layer sandwiched between Ar29 and Ar1 (hereinafter, these areas are also collectively referred to as "eight equally divided areas of the surface layer") is at least 90%.

[0087] As a result, the surface layer of the toner particles can be completely destroyed during fixing and even better fixing performance can be achieved. The proportion of these toner particles is more preferably at least 95%. The proportion of these toner particles is preferably as high as possible, for example, not more than 100%. Any combination of these numerical ranges can be used.

[0088] The proportion of these toner particles can be controlled by, for example, the amount of inorganic fine particles used as a dispersion stabilizer supplementarily added during the granulation step and the stirring rotation speed during the granulation step.

[0089] In TEM observation of a toner particle cross-section, among 100 toner particles having a Dtem within the range of ±10% of the toner particle weight-average particle diameter, the proportion of toner particles having 16 to 30 inorganic fine particles in contact with the core particles in the surface layer is preferably at least 90%. This serves to provide a large amount of toner in which the destruction of the organosilicon polymer surface layer proceeds well during fixing, resulting in even better fixing. At least 95% is more preferred. This toner particle proportion is preferably as high as possible and, for example, is not more than 100%. Any combination of these numerical ranges may be used.

[0090] The average thickness Dav. of the surface layer and the primary particle size Dm of the inorganic fine particles preferably satisfy Dav. / Dm < 1.00. By satisfying Dav. / Dm < 1.00, the particle size of the inorganic fine particles is sufficiently large relative to the average thickness of the surface layer, thereby promoting the destruction of the surface layer by the inorganic fine particles and providing even better fixing performance. Dav. / Dm ≤ 0.80 is more preferred.

[0091] The embodiments of the present disclosure are described in detail below.

[0092] The following compounds are specific examples of the organosilicon compounds used to produce the organosilicon polymer: methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrichlorosilane, ethyltriacetoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltrichlorosilane, butyltrimethoxysilane, butyltriethoxysilane, butyltrichlorosilane, butylmethoxydichlorosilane, butylethoxydichlorosilane, hexyltrimethoxysilane, hexyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane. One of these organosilicon compounds may be used alone, or at least two of them may be used in combination.

[0093] It is known that in a sol-gel reaction, the bonding state of siloxane bonds generated generally changes with changes in the acidity of the reaction medium.

[0094] Specifically, when the medium is acidic, hydrogen ions electrophilically add to the oxygen in a reactive group (e.g., alkoxy group). Then, the oxygen atom in the water molecule coordinates with the silicon atom and undergoes conversion to a hydrosilyl group through a substitution reaction. Assuming that there is enough water, since one oxygen atom of the reactive group (e.g., alkoxy group) is replaced by one H + Attack, therefore, when H in the reaction medium + When the content is low, the substitution reaction to produce hydroxyl groups will be slow. Therefore, the polycondensation reaction occurs before all the reactive groups bonded to the silane are hydrolyzed, and one-dimensional linear polymers or two-dimensional polymers are relatively easy to form.

[0095] On the other hand, when the medium is alkaline, hydroxide ions add to silicon via a pentacoordinate intermediate. Consequently, all reactive groups (e.g., alkoxy groups) are readily eliminated and replaced by silanol groups. In particular, when using silicon compounds with at least three reactive groups in the same silane, hydrolysis and polycondensation proceed three-dimensionally, forming an organosilicon polymer with abundant three-dimensional crosslinks. Furthermore, the reaction is completed within a short time.

[0096] Therefore, the sol-gel reaction for forming the organosilicon polymer is preferably carried out under alkaline conditions, and specifically, when produced in an aqueous medium, the reaction is preferably carried out at a pH of at least 8.0 and a reaction temperature of at least 90°C for a reaction time of at least 5 hours. This supports the formation of an organosilicon polymer with higher strength and excellent durability.

[0097] When the medium used for the above suspension polymerization is an aqueous medium, the following inorganic fine particles can be used as a dispersion stabilizer for particles of the polymerizable monomer composition: for example, tricalcium phosphate, magnesium phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, calcium metasilicate, and calcium sulfate.

[0098] Any production method can be used for the production method of toner particles, but a suspension polymerization method is preferred.

[0099] The toner particle production method by the suspension polymerization method is taken as an example below, and although the toner particle production method is described in detail, the toner particle production method is by no means limited to or by the following method.

[0100] The suspension polymerization method is a production method in which a polymerizable monomer composition containing a polymerizable monomer and an optional colorant is added to an aqueous medium; the polymerizable monomer composition in the aqueous medium is granulated to form particles of the polymerizable monomer composition; and the polymerizable monomer contained in the particles of the polymerizable monomer composition is polymerized to obtain toner particles.

[0101] Each step in the toner particle production method using the suspension polymerization method is described below.

[0102] (Preparation of polymerizable monomer composition)

[0103] A polymerizable monomer composition containing a polymerizable monomer, an organosilicon compound, and optionally a colorant is prepared. When the polymerizable monomer composition contains a colorant, the colorant may be mixed with the other composition after being preliminarily dispersed in the polymerizable monomer using, for example, a stirred media mill, or may be dispersed simultaneously with or after mixing the other composition.

[0104] (Granulation step)

[0105] The polymerizable monomer composition is put into an aqueous medium containing inorganic fine particles serving as a dispersion stabilizer as described above, and the polymerizable monomer composition in the aqueous medium is granulated into droplets by dispersion to obtain droplets of the polymerizable monomer composition.

[0106] During the granulation step, inorganic fine particles adhere to the surface of the polymerizable monomer composition droplets. When the polymerizable monomer composition contains a polar resin, the polar resin is attracted to the interface by the inorganic fine particles attached to the droplet surface. Although polar resins naturally tend to be present on the surface of the polymerizable monomer composition due to their polarity, this attraction to the interface further promotes the presence of polar resins on the surface.

[0107] Granulation step can be carried out for example using a vertical stirred tank equipped with a stirrer producing high shear. For example, commercially available high shear stirrers can be used, for example, Ultra-Turrax (IKA), TK homomixer (Tokushu Kika Kogyo Co., Ltd.), TK Filmics (Tokushu Kika Kogyo Co., Ltd.), Clearmix (M Technique Co., Ltd.), Cavimix (Pacific Machinery & Engineering Co., Ltd.) etc. as stirrers producing high shear. Also used as stirrer is a disperser with a circulation mechanism and in which a serial (inline) high shear can be produced in the circulation mechanism, wherein the circulation mechanism removes a portion of the treatment liquid in the vertical stirred tank from the bottom of the stirred tank and returns it to the stirred tank. For example, commercially available dispersers such as Colloid Mill (IKA), Cavitron (Pacific Machinery & Engineering Co., Ltd.), W Motion (M Technique Co., Ltd.) can be used as serial dispersers. During the granulation step, inorganic fine particles serving as a dispersion stabilizer may be supplementally added. This serves to promote the presence of inorganic fine particles in the surface layer that are in contact with the core particles.

[0108] (Polymerization step)

[0109] The dispersion of the polymerizable monomer composition thus obtained is introduced into the polymerization step to obtain a toner particle dispersion. A common temperature-controllable stirring tank can be used in the polymerization step.

[0110] The polymerization temperature is at least 40°C and preferably 50°C to 90°C. The polymerization temperature may be kept constant throughout the polymerization step or may be increased in the latter half of the polymerization step in order to obtain a desired molecular weight distribution. The stirring blade used for stirring may be any stirring blade that supports maintaining a uniform temperature within the tank, suspends the toner raw material dispersion, and does not cause the raw material dispersion to stagnate. The stirring blade or stirring device can be exemplified by a common stirring blade, such as a paddle blade, a pitched paddle blade, a sweptthree-blade propeller, a propeller blade, a disk turbine blade, a helical ribbon blade, an anchor blade, etc., and can be exemplified by "Fullzone" (Shinko Pantec Co., Ltd.), "Twinstar" (Shinko Pantec Co., Ltd.), "Maxblend" (Sumitomo Heavy Industries, Ltd.), "Super Mix" (Satake Chemical Equipment Mfg., Ltd.) and "Hi-F mixer" (Soken Chemical & Engineering Co., Ltd.).

[0111] Furthermore, by controlling the temperature and pH in the polymerization step to be within the above ranges, the organosilicon compound in the polymerizable monomer composition can be subjected to a sol-gel reaction and a surface layer containing inorganic fine particles and an organosilicon polymer can be formed.

[0112] (Distillation step)

[0113] In order to remove volatile impurities such as, for example, unreacted polymerizable monomers, by-products, etc. as needed, a portion of the aqueous medium may be distilled off in a distillation step after completion of the polymerization. The distillation step may be carried out under normal pressure or under reduced pressure.

[0114] (Washing step, solid-liquid separation step and drying step)

[0115] The polymer particle dispersion can also be treated with an acid or base to remove excess dispersion stabilizer adhering to the polymer particle surface. The polymer particles are then separated from the liquid phase using conventional solid-liquid separation methods and washed with freshly added water to remove the acid or base and any excess dissolved dispersion stabilizer components. This washing step is repeated several times for thorough washing, followed by solid-liquid separation to obtain toner particles. The resulting toner particles can then be dried using known drying methods, as needed.

[0116] (Grading steps)

[0117] When the toner particles thus obtained are required to have a sharper particle size, particles having a particle size distribution other than the desired particle size distribution may be classified and removed by classification using, for example, an air classifier.

[0118] The following vinyl polymerizable monomers are preferred examples of the above-mentioned polymerizable monomers: styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, and p-phenylstyrene; acrylic polymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl ethyl acrylate, diethyl ethyl phosphate, Acrylates, dibutyl phosphate ethyl acrylate, and 2-benzoyloxyethyl acrylate; methacrylic acid-based polymerizable monomers, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate, and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters, for example, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, and vinyl formate; vinyl ethers, for example, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; and vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.

[0119] The content of the polymerizable monomer in the polymerizable monomer composition is preferably 50% by mass to 100% by mass and more preferably 70% by mass to 100% by mass.One of these polymerizable monomers may be used alone or a combination of at least two thereof may be used.

[0120] The following are examples of polymerization initiators that can be used during polymerization: azo-based polymerization initiators and diazo-based polymerization initiators, such as 2,2′-azobis(2,4-divaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis(cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile, and peroxide-based polymerization initiators, such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, and tert-butyl peroxypivalate. The content of the polymerization initiator is preferably 0.5 to 30.0 parts by mass relative to 100 parts by mass of the polymerizable monomer. A single one of these polymerization initiators can be used alone, or at least two of them can be used in combination.

[0121] A chain transfer agent may be added during polymerization to control the molecular weight of the binder resin constituting the toner particles. The preferred amount of addition is 0.001 to 15.0 parts by mass relative to 100 parts by mass of the polymerizable monomer.

[0122] A crosslinking agent may be added during polymerization to control the molecular weight of the binder resin constituting the toner particles. For example, a crosslinking monomer may be used as the crosslinking agent.

[0123] The crosslinking monomer can be exemplified by the following: divinylbenzene, bis(4-acryloyloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, each diacrylate of polyethylene glycol #200, #400 and #600, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester diacrylate (MANDA, Nippon Kayaku Co., Ltd.), and crosslinking monomers provided by changing the acrylate in the foregoing to methacrylate.

[0124] Examples of the multifunctional crosslinking monomer include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, and acrylic acid oligoesters and methacrylates of the foregoing, as well as 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane, diaryl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, and diallyl chlorendic acid.

[0125] The preferred addition amount of the cross-linking agent is 0.001 to 15.0 parts by mass relative to 100 parts by mass of the polymerizable monomer.

[0126] The colorant is not particularly limited, and known colorants given below can be used.

[0127] For example, yellow iron oxide, Naples Yellow, Naphthol Yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, condensed azo compounds such as Permanent Yellow NCG and Tartrate Yellow Lake, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds can be used as yellow pigments. Specific examples include CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, and 180.

[0128] The orange pigment can be exemplified by the following: Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Benzidine Orange G, Indanthrene Brilliant Orange RK, and Indanthrene Brilliant Orange GK.

[0129] For example, red iron oxides; condensed azo compounds such as Fast Red 4R, Lithol Red, Pyrazolone Red, Watching Red calcium salt, Red Lake C, Red Lake D, Brilliant Carmine 6B, Brilliant Carmine 3B, Eosin Lake, Rhodamine Lake B, and Alizarin Lake; diketopyrrolopyrrole compounds; anthraquinone; quinacridone compounds; basic dye lake compounds; naphthol compounds; benzimidazolone compounds; thioindigo compounds; and perylene compounds are examples of red pigments.

[0130] Examples of blue pigments include basic blue lakes; Victoria Blue Lake; copper phthalocyanine compounds and their derivatives, such as phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, Fast Sky Blue, and Indanthrene BG; anthraquinone compounds; and basic dye lake compounds. Specific examples include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0131] Violet pigments can be exemplified by Fast Violet B and Methyl Violet Lake.

[0132] Green pigments can be exemplified by Pigment Green B, Malachite Green Lake, and Final Yellow Green G.

[0133] The white pigment can be exemplified by zinc white, titanium oxide, antimony white, and zinc sulfide.

[0134] The black pigment can be exemplified by carbon black, aniline black, non-magnetic ferrite and magnetite, and a black pigment provided by toning to black using the above-mentioned yellow-based colorant, red-based colorant and blue-based colorant.

[0135] A single one of these colorants can be used alone or a combination of at least two thereof can be used. These colorants can also be used in the form of a solid solution. The colorant content is preferably 3.0 to 15.0 parts by mass relative to 100 parts by mass of the binder resin or polymerizable monomer.

[0136] A charge control agent other than a resin having an ionic functional group with a specific pKa value during toner production may be used in the toner. Known charge control agents can be used as such a charge control agent. The amount of the charge control agent added is preferably 0.01 to 10.0 parts by mass per 100 parts by mass of the binder resin or polymerizable monomer.

[0137] The toner particles can be used as is as a toner, or various organic fine powders or inorganic fine powders can be added to the toner particles to provide a toner. Considering durability when added to the toner particles, the organic or inorganic fine powder preferably has a particle size of not more than one-tenth the weight-average particle size of the toner particles. For example, the following can be used for the organic or inorganic fine powder.

[0138] (1) Flowability-imparting agents: silica, alumina, titanium oxide, carbon black, and carbon fluoride.

[0139] (2) Abrasives: metal oxides (e.g., strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide), nitrides (e.g., silicon nitride), carbides (e.g., silicon carbide), metal salts (e.g., calcium sulfate, barium sulfate, calcium carbonate).

[0140] (3) Lubricant: fluorine-based resin powder (eg, vinylidene fluoride, polytetrafluoroethylene), metal salt of fatty acid (eg, zinc stearate, calcium stearate).

[0141] (4) Charge control particles: metal oxides (eg, tin oxide, titanium oxide, zinc oxide, silicon dioxide, aluminum oxide), carbon black.

[0142] Organic or inorganic fine powders can also be used to treat the surface of toner particles, thereby improving toner fluidity and providing more uniform toner particle charging. Examples of treatment agents for hydrophobizing organic or inorganic fine powders include unmodified silicone varnishes, various modified silicone varnishes, unmodified silicone oils, various modified silicone oils, silane compounds, silane coupling agents, organosilicon compounds other than the aforementioned, and organotitanium compounds. Any one of these treatment agents can be used alone, or at least two of them can be used in combination.

[0143] The following describes methods for measuring various physical property values ​​involved in the present disclosure.

[0144] <Method for Separating THF-Insoluble Matter in Toner Particles for NMR Measurement>

[0145] The tetrahydrofuran (THF)-insoluble matter in the toner particles is separated as follows.

[0146] 10.0 g of toner particles were weighed and placed in an extraction thimble (No. 86R, Toyo Roshi Kaisha, Ltd.), which was then placed in a Soxhlet extractor. Extraction was performed for 20 hours using 200 mL of THF as the solvent, and the filtered residue in the extraction thimble was vacuum-dried at 40°C for several hours to obtain THF-insoluble matter in the toner particles for NMR measurement. If the toner particles contain a magnetic substance, for example, a magnet may be used for preliminary separation during extraction.

[0147] When the toner particle surfaces have been treated with, for example, an external additive, the toner particles are obtained by removing the external additive using the following method.

[0148] A sucrose concentrate was prepared by adding 160 g of sucrose (Kishida Chemical Co., Ltd.) to 100 mL of deionized water and dissolving the solution while heating it in a water bath. 31 g of the sucrose concentrate and 6 mL of Contaminon N (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments at pH 7 containing a nonionic surfactant, an anionic surfactant, and an organic builder, available from Wako Pure Chemical Industries, Ltd.) were introduced into a centrifuge tube to prepare a dispersion. 1.0 g of toner was added to the dispersion, and lumps of the toner were broken up using, for example, a scraper.

[0149] The centrifuge tube was shaken for 20 minutes with a shaking table at 350 strokes per minute (spm). After shaking, the solution was transferred to a glass tube (50 mL) for a horizontal rotor apparatus and separated using a centrifuge at 3,500 rpm for 30 minutes. This process separates the external additives that have been separated from the toner particles. The toner was fully separated from the aqueous solution by visual inspection and, for example, a scraper was used to reclaim the toner separated into the uppermost layer. The recovered toner was filtered on a reduced pressure filter and then dried in a dryer for at least one hour to obtain the toner particles.

[0150] This process is repeated several times to ensure the desired amount.

[0151] (Method for Confirming the Structure Given by Formula (T3))

[0152] The structure represented by formula (T3) in the organosilicon polymer contained in the toner particles is confirmed using the following method.

[0153] pass 13 C-NMR and 29 The presence or absence of an alkyl group or a phenyl group represented by R in formula (T3) can be confirmed by Si-NMR. 1 H-NMR, 13 C-NMR and 29 The details of the structure given by formula (T3) were confirmed by Si-NMR. The instruments used and the measurement conditions are shown below.

[0154] ( 1 H-NMR measurement conditions)

[0155] Instrument: AVANCE III 500 from Bruker

[0156] Probe: 4mm MAS BB / 1H

[0157] Measuring temperature: room temperature

[0158] Sample rotation rate: 6kHz

[0159] Sample: 150 mg of a measurement sample (THF-insoluble matter in the above-mentioned toner particles for NMR measurement) is introduced into a sample tube having a diameter of 4 mm.

[0160] This method was used to confirm the presence of an alkyl group or a phenyl group represented by R in formula (T3). If a signal was confirmed, the structure having formula (T3) was recorded as "present".

[0161] ( 13 C-NMR (solid state) measurement conditions

[0162] Measurement core frequency: 125.77MHz

[0163] Reference substance: Glycine (external standard: 176.03 ppm)

[0164] Observation width: 37.88kHz

[0165] Measurement method: CP / MAS

[0166] Contact time: 1.75msec

[0167] Repeat time: 4 seconds

[0168] Scan times: 2048 times

[0169] LB value: 50Hz

[0170] ( 29 Si-NMR (solid state) measurement conditions

[0171] Instrument: AVANCE III 500 from Bruker

[0172] Probe: 4mm MAS BB / 1 H

[0173] Measuring temperature: room temperature

[0174] Sample rotation rate: 6kHz

[0175] Sample: 150 mg of a measurement sample (THF-insoluble matter in toner particles for NMR measurement) is introduced into a sample tube having a diameter of 4 mm.

[0176] Measurement core frequency: 99.36MHz

[0177] Reference substance: DSS (external standard: 1.534 ppm)

[0178] Observation width: 29.76kHz

[0179] Measurement method: DD / MAS, CP / MAS

[0180] 29 Si 90°

[0181] Pulse width: 4.00μsec@-1dB

[0182] Contact time: from 1.75msec to 10msec

[0183] Repeat time: 30 seconds (DD / MAS), 10 seconds (CP / MAS)

[0184] Scan times: 2048 times

[0185] LB value: 50Hz

[0186] [Method for measuring the ratio of the peak area attributable to the structure given by formula (T3)]

[0187] In the THF insoluble matter in the toner particles 29 After Si-NMR measurement, the toner particles were subjected to peak separation into the following Q1 structure, Q2 structure, Q3 structure, and Q4 structure by curve fitting of a plurality of silane components having different substituents and bonding groups, and the mol% of each component was calculated from the peak area ratio.

[0188] Curve fitting was performed using EXcalibur for Windows (registered trademark) version 4.2 (EX series) software for JNM-EX400 from JEOL Ltd. Click "1D Pro" from the menu icon and load the measurement data.

[0189] Then perform curve fitting by selecting "Curve Fitting Function" from the "Command" on the menu bar. Figure 3 Peak resolution is performed so that the peak of the synthetic peak differential (a), which is the difference between the synthetic peak (b) and the measurement result (d), is minimized.

[0190] The area of ​​the Q1 structure, the area of ​​the Q2 structure, the area of ​​the Q3 structure, and the area of ​​the Q4 structure are measured, and SQ1, SQ2, SQ3, and SQ4 are determined using the formulas given below.

[0191] Q1 structure: (R 1 )(R 2 )(R 3 )SiO 1 / 2 Formula (2)

[0192] Q2 structure: (R 4 )(R 5 )Si(O 1 / 2 )2 Formula (3)

[0193] Q3 structure: R 6 Si(O 1 / 2 )3 Formula (4)

[0194] Q4 structure: Si(O 1 / 2 )4 Formula (5)

[0195]

[0196] R in formulas (2), (3) and (4) 1 、R 2 、R 3 、R 4 、R 5 and R 6 represents a silicon-bonded organic group, a halogen atom, a hydroxyl group, or an alkoxy group.

[0197] Silane monomers were identified from chemical shift values, and the total peak area of ​​the organosilicon polymer was taken as the peak area from the toner particles. 29 The total peak area in Si-NMR measurement is the sum of the area of ​​the Q1 structure, the area of ​​the Q2 structure, the area of ​​the Q3 structure, and the area of ​​the Q4 structure.

[0198] SQ1+SQ2+SQ3+SQ4=1.000

[0199] SQ1={area of ​​Q1 structure / (area of ​​Q1 structure+area of ​​Q2 structure+area of ​​Q3 structure+area of ​​Q4 structure)}

[0200] SQ2 = {area of ​​Q2 structure / (area of ​​Q1 structure + area of ​​Q2 structure + area of ​​Q3 structure + area of ​​Q4 structure)}

[0201] SQ3 = {area of ​​Q3 structure / (area of ​​Q1 structure + area of ​​Q2 structure + area of ​​Q3 structure + area of ​​Q4 structure)}

[0202] SQ4 = {area of ​​Q4 structure / (area of ​​Q1 structure + area of ​​Q2 structure + area of ​​Q3 structure + area of ​​Q4 structure)}

[0203] The peak area of ​​the structure given by the following formula (T3) is at least 5.0% relative to the total peak area of ​​the organosilicon polymer. That is, in the measurement method described above, the peak area of ​​the structure given by R-SiO 3 / 2 The structure is given a value of SQ3 as defined above. The value is at least 0.05.

[0204] R-Si(O 1 / 2 )3 (T3)

[0205] The chemical shift values ​​of silicon in the Q1 structure, Q2 structure, Q3 structure, and Q4 structure are given below.

[0206] Example of Q1 structure (R 1 =R 2 =-OC2H5, R 3 =-CH3): -47ppm

[0207] Example of Q2 structure (R 4 =-OC2H5, R 5 =-CH3): -56ppm

[0208] Example of Q3 structure (R 6 =-CH3): -65ppm

[0209] In the case of the Q4 structure, the chemical shift values ​​of silicon are as follows.

[0210] Q4 structure: -108ppm

[0211] <Method for measuring the average thickness Dav. of the surface layer and the ratio of the Arn line segments where FRAn (thickness of the surface layer) does not exceed 5.0 nm by observing a cross section of a toner particle using a transmission electron microscope (TEM)>

[0212] Observation of the toner particle cross section is performed using the following method.

[0213] In a specific method for observing toner particle cross-sections, toner particles are thoroughly dispersed in a room-temperature curable epoxy resin and then cured for two days in a 40°C atmosphere. A thin sheet sample is cut from the resulting cured product using a microtome equipped with a diamond blade. The toner particle cross-section is observed by magnifying the sample using a transmission electron microscope (TEM) (Tecnai TF20XT electron microscope from FEI) at a magnification of 10,000X to 100,000X.

[0214] In this disclosure, the presence of the organosilicon polymer in the surface layer is confirmed by utilizing the difference in atomic weight between the atoms in the resin and the organosilicon compound used, and by utilizing the fact that a larger atomic weight provides a sharper contrast. Staining with ruthenium tetroxide and staining with osmium tetroxide are used to provide contrast between the materials.

[0215] Toner particles whose Dtem (determined from a cross section of the toner particles obtained from a TEM micrograph) is within the range of ±10% of the weight-average particle size of the toner particles (determined by the method given below using a Coulter Counter) are target toner particles for measuring the average thickness Dav. of the surface layer of the toner particles by TEM and for measuring the proportion of Arn line segments in which FRAn (surface layer thickness) does not exceed 5.0 nm.

[0216] [Method of measuring Dtem from a toner cross section obtained from a TEM micrograph]

[0217] The toner particle cross section is divided into 32 equal parts (see FIG. 1 ) using the intersection between the major axis L (as the maximum diameter in the cross section of the toner particle) and the axis L90 (passing through the midpoint of the major axis L and perpendicular thereto) as the center. Figure 2 ). That is, 32 line segments from the midpoint of the long axis L to the surface of the toner particle are formed by drawing 16 straight lines that pass through the midpoint of the long axis L and cross the cross section at the midpoint at an equal intersection angle (intersection angle = 11.25°). Then, Arn (n = 1 to 32) is used as each line segment (division axis) from the center to the surface layer of the toner particle, RAn is used as the length of each line segment (division axis), and FRAn (n = 1 to 32) is used as the thickness of the surface layer on the line segment Arn.

[0218] The following formula is then used to determine Dtem determined from a toner cross section obtained from a TEM micrograph.

[0219] Dtem=(RA1+RA2+RA3+RA4+RA5+RA6+RA7+RA8+RA9+RA10+RA11+RA12+RA13+RA14+RA15+RA16+RA1 7+RA18+RA19+RA20+RA21+RA22+RA23+RA24+RA25+RA26+RA27+RA28+RA29+RA30+RA31+RA32) / 16

[0220] [Measurement of Average Thickness (Dav.) of Surface Layer of Toner Particles]

[0221] The average thickness (Dav.) of the surface layer of the toner particles is determined using the following method: First, for a toner particle having a Dtem within the range of ±10% of the weight average particle diameter of the toner particles, the average thickness D(n) of the surface layer is determined using the following method.

[0222] D(n) = (the sum of the thicknesses of the surface layer at 32 locations on the dividing axis) / 32 = (FRA1+FRA2+FRA3+FRA4+FRA5+FRA6+FRA7+FRA8+FRA9+FRA10+FRA11+FRA12+FRA13+FRA14+FRA15+FRA16+FRA17+FRA18+FRA19+FRA20+FRA21+FRA22+FRA23+FRA24+FRA25+FRA26+FRA27+FRA28+FRA29+FRA30+FRA31+FRA32) / 32

[0223] In order to obtain the average value, for 100 colorant particles whose Dtem is within the range of ±10% of the weight-average particle size of the colorant particles, the average thickness D(n) (n=1 to 100) of the surface layer of the colorant particles is determined, and the average value of each colorant particle is calculated and used as the average thickness (Dav.) of the surface layer of the colorant particles.

[0224] Dav.={D(1)+D(2)+D(3)+D(4)+D(5)+·····+D(100)} / 100

[0225] [Method for measuring the ratio of Arn line segments with FRAn (surface layer thickness) not exceeding 5.0 nm]

[0226] First, for a toner particle having a Dtem within the range of ±10% of the toner particle weight average particle size, the ratio of Arn line segments having a FRAn (surface layer thickness) of not more than 5.0 nm is determined using the following method.

[0227] [Ratio of Arn line segments with FRAn (surface thickness) not exceeding 5.0 nm] = ({Number of Arn line segments with FRAn (surface thickness) not exceeding 5.0 nm} / 32) × 100

[0228] This calculation is performed for 100 toner particles whose Dtem is within the range of ±10% of the weight-average particle size of the toner particles, and, for these 100 values, the average value is determined and used as the proportion of the Arn line segments where the FRAn (surface layer thickness) of the toner particles does not exceed 5.0 nm.

[0229] <Method for Measuring the Number of Inorganic Fine Particles in Contact with Core Particles in Surface Layer, and Method for Measuring the Ratio of Toner Particles Where the Number is 16 to 30>

[0230] When observing the cross section of the toner particles using a transmission electron microscope (TEM), a bright field image of the cross section of the toner particles was obtained using a Tecnai TF20XT electron microscope from FEI at an accelerating voltage of 200 kV. Then, a GIF Tridiem EELS detector from Gatan, Inc. was used to obtain an EF mapping image of the Si-K end (99 eV) by a three-window method, and the elements of each inorganic fine particle were identified, and the number of inorganic fine particles in contact with the core particles in the surface layer was counted. This measurement was performed on 100 toner particles whose Dtem was within the range of ±10% of the weight-average particle size of the toner particles, and the average value was used as the number of inorganic fine particles in contact with the core particles in the surface layer. The ratio of toner particles having 16 to 30 inorganic fine particles in contact with the core particles in the surface layer was also similarly determined.

[0231] This elemental analysis is also used to determine whether the inorganic fine particles contain at least one selected from the group consisting of a calcium element and a magnesium element.

[0232] <Method for Measuring the Ratio of Toner Particles Having At least One Inorganic Fine Particle Present in the Core Particle and Not in Contact with the Surface Layer>

[0233] The observation of the inorganic fine particles present in the core particles and not in contact with the surface layer can be performed according to the method for measuring the number of inorganic fine particles in contact with the core particles in the surface layer described above. This observation is performed on 100 toner particles having a Dtem within the range of ±10% of the weight-average particle diameter of the toner particles to determine the proportion of toner particles having at least one inorganic fine particle present in the core particles and not in contact with the surface layer.

[0234] <Measurement of Number Average Particle Diameter Dm of Primary Particle Size of Inorganic Fine Particles>

[0235] The number average particle diameter Dm of the primary particle diameter of the inorganic fine particles is determined by measuring the particle diameters of at least 100 inorganic fine particles using an enlarged image of the toner particle cross section, and calculating the arithmetic average value as the number average particle diameter Dm. When the particle shape is spherical, the absolute maximum length is used as the particle diameter; when the particle shape has a major diameter and a minor diameter, the major diameter is used as the particle diameter.

[0236] <Ratio of Toner Particles in Which At Least One Inorganic Fine Particle Exists in Each of Eight-Divided Regions of the Surface Layer>

[0237] Using a method for measuring the average thickness (Dav.) of the surface layer of the colorant particles and the proportion of Arn line segments in which FRAn (surface layer thickness) does not exceed 5.0 nm, in which the measurement is performed by observing the cross section of the colorant particles using a transmission electron microscope (TEM), the proportion of the colorant particles in which at least one inorganic fine particle exists in each of the eight equally divided regions of the surface layer is determined as the proportion of the colorant particles in which at least one inorganic fine particle exists in each of the following regions per 100 toner particles whose Dtem is within the range of ±10% of the weight-average particle size of the colorant particles: the region of the surface layer sandwiched between Ar1 and Ar5, the region of the surface layer sandwiched between Ar5 and Ar9, the region of the surface layer sandwiched between Ar9 and Ar13, the region of the surface layer sandwiched between Ar13 and Ar17, the region of the surface layer sandwiched between Ar17 and Ar21, the region of the surface layer sandwiched between Ar21 and Ar25, the region of the surface layer sandwiched between Ar25 and Ar29, and the region of the surface layer sandwiched between Ar29 and Ar1.

[0238] <Method for measuring weight-average particle diameter (D4) of toner particles>

[0239] The weight-average particle size (D4) of the toner particles was determined as follows. The measuring instrument used was the "Coulter Counter Multisizer 3" (registered trademark, Beckman Coulter, Inc.), a precision particle size distribution measuring instrument that operates based on the pore resistance method and is equipped with a 100 μm aperture. The accompanying dedicated software, "Beckman Coulter Multisizer 3 Version 3.51" (Beckman Coulter, Inc.), was used to set measurement conditions and analyze measurement data. Regarding the number of effective measurement channels, measurements were performed on 25,000 channels.

[0240] The aqueous electrolyte solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to provide a concentration of 1 mass %, and, for example, “ISOTON II” (Beckman Coulter, Inc.) can be used.

[0241] Before measurement and analysis, the dedicated software was set as follows.

[0242] In the "Standard Operating Method Change (SOMME)" screen of the dedicated software, the total count in control mode was set to 50,000 particles; the number of measurements was set to 1; and the Kd value was set to the value obtained using "Standard Particles 10.0 μm" (Beckman Coulter, Inc.). The threshold and noise level were automatically set by pressing the "Threshold / Noise Level Measurement Button." Furthermore, the current was set to 1600 μA; the gain was set to 2; the electrolyte solution was set to ISOTON II; and a "Post-Measurement Orifice Tube Flush" check was performed.

[0243] In the "Pulse to Particle Size Conversion Settings" interface of the dedicated software, the element spacing was set to logarithmic particle size; the particle size element was set to 256 particle size elements; and the particle size range was set to 2 μm to 60 μm.

[0244] The specific measurement process is as follows.

[0245] (1) 200 mL of the above electrolyte aqueous solution was placed in a 250 mL glass round-bottom beaker dedicated to the Multisizer 3. This was placed in a sample holder and stirred counterclockwise at 24 revolutions per second using a stirring rod. Dirt and bubbles were removed from the nozzle using the "Nozzle Rinse" function in the dedicated software.

[0246] (2) 30 mL of the aqueous electrolyte solution was introduced into a 100 mL flat-bottom beaker made of glass, and 0.3 mL of a dilution solution prepared by diluting "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments containing a nonionic surfactant, an anionic surfactant, and an organic builder at pH 7, from Wako Pure Chemical Industries, Ltd.) with three times (by mass) deionized water was added thereto as a dispersant.

[0247] (3) Prepare the "Ultrasonic Dispersion System Tetora 150" (Nikkaki Bios Co., Ltd.); this is an ultrasonic disperser with a power output of 120 W and equipped with two oscillators (oscillation frequency = 50 kHz) configured to be 180° phase-shifted. 3.3 L of deionized water was introduced into the water tank of the ultrasonic disperser, and 2 mL of Contaminon N was added to the water tank.

[0248] (4) The beaker described in (2) is placed in the beaker fixing hole of the ultrasonic disperser and the ultrasonic disperser is activated. The height position of the beaker is adjusted so as to maximize the resonance state of the liquid surface of the aqueous electrolyte solution in the beaker.

[0249] (5) While ultrasonic waves are being irradiated on the electrolyte aqueous solution in the beaker set up according to (4), 10 mg of the toner particles are added to the electrolyte aqueous solution in small aliquots and dispersed. The ultrasonic dispersion treatment is continued for an additional 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately controlled to 10°C to 40°C.

[0250] (6) Using a pipette, the aqueous electrolyte solution containing dispersed toner particles prepared in (5) is added dropwise to the round-bottom beaker set in the sample holder as described in (1), adjusting to provide a measurement concentration of 5%. Measurement is then performed until the number of particles measured reaches 50,000.

[0251] (7) Analyze the measurement data using the dedicated software included with the instrument and calculate the weight-average particle size (D4). When the dedicated software is set to Graph / Volume %, the "Average Diameter" on the "Analysis / Volume Statistics (Arithmetic Mean)" screen is the weight-average particle size (D4).

[0252] Example

[0253] The present disclosure is described in detail below using Examples and Comparative Examples, but the present disclosure is not limited to or by these Examples and Comparative Examples. Unless otherwise specifically stated, the "parts" described in Examples and Comparative Examples are based on mass in all cases.

[0254] <Polyester Resin Production Example>

[0255] Terephthalic acid: 11.1 mol

[0256] Bisphenol A propylene oxide 2 mol adduct: 10.8 mol

[0257] These monomers were introduced into an autoclave along with an esterification catalyst. The autoclave was equipped with a pressure reducing device, a water separation device, a nitrogen introduction device, a temperature measuring device, and a stirring device. While reducing the pressure under a nitrogen atmosphere, a reaction was conducted by conventional methods at 220°C until the Tg reached 70°C to obtain a polyester resin. The weight average molecular weight (Mw) was 8,200, and the number average molecular weight (Mn) was 3,220.

[0258] <Toner 1 Production Example>

[0259] (Preparation of an aqueous dispersion medium containing a dispersion stabilizer for supplementary addition)

[0260] The following materials were introduced into 350 parts of deionized water in a reactor and, while purging with N2, maintained at a temperature of 60°C for 60 minutes.

[0261] 14.0 parts of sodium phosphate

[0262] 7.0 parts of 10% hydrochloric acid

[0263] While stirring at 12,000 rpm using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.), a calcium chloride aqueous solution obtained by dissolving 8.0 parts of calcium chloride in 20 parts of deionized water was introduced all at once to prepare an aqueous dispersion medium for supplementary addition containing calcium phosphate.

[0264] (Preparation of aqueous dispersion medium for granulation)

[0265] The following materials were introduced into 1,000 parts of deionized water in a reactor, and, while purging with N 2 , maintained at a temperature of 60° C. for 60 minutes.

[0266] 14.0 parts of sodium phosphate

[0267] 7.0 parts of 10% hydrochloric acid

[0268] While stirring at 12,000 rpm using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.), a calcium chloride aqueous solution obtained by dissolving 8.0 parts of calcium chloride in 20 parts of deionized water was introduced all at once to prepare an aqueous dispersion medium for granulation containing calcium phosphate.

[0269] A polymerizable monomer composition was then prepared using the following raw materials; this step was defined as a dissolution step.

[0270]

[0271] A polymerizable monomer composition was prepared by dispersing these raw materials for 3 hours using an attritor (Nippon Coke & Engineering Co., Ltd.). The polymerizable monomer composition was then transferred to another container and maintained at 63° C. for 5 minutes while stirring. 20.0 parts of a polymerization initiator, t-butyl peroxypivalate (50% toluene solution), was then added and maintained for 5 minutes while stirring (dissolution step).

[0272] The polymerizable monomer composition was introduced into the aqueous dispersion medium for granulation and granulated for 5 minutes while stirring with a high-speed stirrer. Then, 30 parts of the aqueous dispersion medium containing a dispersion stabilizer was added for supplemental addition, and granulation was continued for an additional 15 minutes (granulation step). Stirring during granulation was performed at 12,000 rpm, and the granulation temperature was 60°C.

[0273] The high-speed stirrer was replaced with a propeller stirrer and the internal temperature was raised to 70°C. The temperature increase took 10 minutes. The reaction was continued for 5 hours while gently stirring. The pH was 5.1. This was defined as Reaction 1.

[0274] Next, the pH was adjusted to 8.0 over 10 minutes by adding a 1.0 mol / L aqueous NaOH solution, and the temperature within the vessel was raised to 85°C. The temperature increase took 20 minutes. The temperature within the vessel was then maintained at 85°C for 3.0 hours. This step was defined as Reaction 2.

[0275] After completing step 2 of reaction, the reflux condenser was removed and a distillation apparatus capable of fraction recovery was installed. The temperature within the vessel was then raised to 100°C. The time required to raise the temperature was 30 minutes. The temperature within the vessel was then maintained at 100°C for 5.0 hours. The pH at the completion of this step was 8.0. The time from the installation of the distillation apparatus capable of fraction recovery to the completion of the 5.0-hour hold at 100°C was defined as the distillation step. The hold temperature was designated as the distillation temperature, and the hold time was designated as the distillation time. Residual monomers and other solvents were removed during this step.

[0276] After the distillation step, cooling to 30°C was performed, dilute hydrochloric acid was added to the container to lower the pH to 1.5 and dissolve the dispersion stabilizer, and filtration was performed. The filter cake obtained after filtration was not taken out and was washed by adding 700 parts of deionized water and filtering again.

[0277] Then, the filter cake was taken out after filtration and dried under vacuum at 30° C. for 1 hour.

[0278] A wind classifier was used to separate the coarse powder and fine powder. The particles thus obtained were designated as Toner Particles 1. Toner Particles 1 themselves were designated as Toner 1. The production conditions and formulation of Toner Particles 1 are shown in Tables 1, 2-1, and 2-2, and the physical properties of Toner 1 are shown in Table 3.

[0279] <Toners 2 to 6 and 8 to 22 Production Examples>

[0280] The physical properties of the obtained toners 2 to 6 and 8 to 22 are shown in Table 3.

[0281] <Toner 7 Production Example>

[0282] (Preparation of an aqueous dispersion medium containing a dispersion stabilizer for supplementary addition)

[0283] The following materials were introduced into 350 parts of deionized water in a reactor and, while purging with N2, maintained at a temperature of 60°C for 60 minutes.

[0284] 12.0 parts of sodium hydroxide

[0285] 5.0 parts of 10% hydrochloric acid

[0286] While stirring at 12,000 rpm using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.), a magnesium chloride aqueous solution in which 6.0 parts of magnesium chloride was dissolved in 20 parts of deionized water was introduced all at once to prepare an aqueous medium containing dispersion-stable inorganic fine particles for supplementary addition containing magnesium hydroxide.

[0287] (Preparation of aqueous dispersion medium for granulation)

[0288] The following materials were introduced into 1,000 parts of deionized water in a reactor, and, while purging with N 2 , maintained at a temperature of 60° C. for 60 minutes.

[0289] 12.0 parts of sodium hydroxide

[0290] 5.0 parts of 10% hydrochloric acid

[0291] While stirring at 12,000 rpm using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.), a magnesium chloride aqueous solution in which 6.0 parts of magnesium chloride was dissolved in 20 parts of deionized water was introduced all at once to prepare an aqueous granulation medium containing magnesium hydroxide.

[0292] The physical properties of the obtained Toner 7 are shown in Table 3.

[0293] <Toner 23 Production Example>

[0294] (Preparation of Binder Resin Fine Particle Dispersion Liquid 1)

[0295] 80.0 parts of styrene, 18.7 parts of butyl acrylate, and 1.3 parts of acrylic acid, a monomer for providing carboxyl groups, were mixed and dissolved. To this solution, an aqueous solution of 4.0 parts of sodium dodecylbenzenesulfonate mixed in 150 parts of deionized water was added and dispersed. While slowly stirring for 10 minutes, an aqueous solution of 0.3 parts of potassium persulfate mixed in 10 parts of deionized water was also added. After nitrogen displacement, emulsion polymerization was carried out at 70°C for 6 hours. After completion of polymerization, the reaction solution was cooled to room temperature and deionized water was added to obtain a binder resin fine particle dispersion 1 having a solid concentration of 20.0% by mass and a volume-based median particle size of 0.2 μm.

[0296] (Preparation of Polyester Resin Particle Dispersion)

[0297] A 3-liter jacketed reaction tank (BJ-30N, Tokyo Rika Kikai Co., Ltd.) equipped with a condenser, a thermometer, a water dropping device, and an anchor stirring blade was maintained at 40° C. in a water circulation type thermostatic bath. A mixed solvent of 160.0 parts of ethyl acetate and 100.0 parts of isopropyl alcohol was introduced into the reaction tank; 300.0 parts of an amorphous polyester resin (a condensate of terephthalic acid and propylene oxide-modified (2 mol adduct) bisphenol A, Mw=7,800, Tg=70° C., acid value=8.0 mg KOH / g) was introduced therein; and dissolved by stirring at 150 rpm using a Three-One Motor to obtain an oil phase. 14.0 parts of a 10.0 mass % ammonia aqueous solution was added dropwise to the stirred oil phase over a 5 minute addition time, mixed for 10 minutes, and then 900.0 parts of deionized water was added dropwise at a rate of 7.0 parts per minute to induce phase inversion and provide an emulsion.

[0298] 800.0 parts of the obtained emulsion and 700.0 parts of deionized water were then introduced into a 2-liter recovery bottle and installed in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit through an inserted capture ball. While rotating the recovery bottle, it was heated on a 60°C hot water bath and the pressure was reduced to 7 kPa to remove the solvent, while taking care to avoid violent boiling. When the solvent recovery amount reached 1,100.0 parts, it was returned to normal pressure; the recovery bottle was water-cooled to obtain a dispersion. No solvent odor was detected from the resulting dispersion. The volume-based median particle size of the polyester resin fine particles in the dispersion was 130 nm. Deionized water was added to adjust the solid concentration to 20.0% by mass, and it was designated as a polyester resin fine particle dispersion.

[0299] (Preparation of Colorant Fine Particle Dispersion)

[0300] Copper phthalocyanine pigment (Pigment Blue 15:3): 100.0 parts

[0301] Anionic surfactant, sodium dodecylbenzenesulfonate: 16.0 parts

[0302] Deionized water: 384.0 parts

[0303] The above substances were mixed and dissolved, and dispersed for 60 minutes using an Ultimizer high-pressure impact disperser (HJP30006, Sugino Machine Limited) to produce a colorant fine particle dispersion in which the colorant was dispersed. The volume-based median particle diameter of the colorant fine particles in the colorant fine particle dispersion was 130 nm, and the colorant fine particle concentration was 20.0% by mass.

[0304] (Preparation of Release Agent Fine Particle Dispersion)

[0305] Fischer-Tropsch wax (melting point: 78°C): 100.0 parts

[0306] · Anionic surfactant, 16.0 parts sodium dodecylbenzenesulfonate

[0307] Deionized water: 384.0 parts

[0308] The aforementioned components were mixed, and the release agent was dissolved at an internal temperature of 120°C using a pressure-dispensing homogenizer (Gaulin Homogenizer, Gaulin Co.). The mixture was then dispersed at a dispersion pressure of 5 MPa for 120 minutes, and then at 40 MPa for 360 minutes, followed by cooling to obtain a release agent fine particle dispersion. The fine particles in this release agent fine particle dispersion had a volume-based median particle size of 225 nm. Subsequently, deionized water was added to adjust the solids concentration to 20.0% by mass.

[0309] (Preparation of Resin Particles 1)

[0310]

[0311] These components were introduced into a 3-liter reactor equipped with a thermometer, a pH meter, and a stirrer, and the pH was adjusted to 3.0 by adding 0.3 mol / L nitric acid at a temperature of 25° C. Then, while dispersing at 5,000 rpm using a homogenizer (Ultra-Turrax T50, IKA Japan KK), 130.0 parts of an aqueous aluminum chloride solution (0.3% by mass) was added and dispersion was performed for 6 minutes.

[0312] The reaction vessel was then equipped with a stirrer and a jacketed resistance heater, and the stirrer rotation speed was adjusted to sufficiently stir the slurry. While continuing to stir, the temperature was raised at a rate of 0.2°C / minute to 40°C. After exceeding 40°C, the temperature was raised at a rate of 0.05°C / minute to 90°C, and a heat treatment step was performed at 90°C for 180 minutes. The vessel was then cooled to 20°C using cooling water.

[0313] After cooling, the slurry was passed through a nylon mesh with 15 μm openings to remove coarse powder. Nitric acid was added to the resin particle dispersion that had passed through the mesh to adjust the pH to 6.0. Vacuum filtration was then performed using an aspirator. The resin particles remaining on the filter paper were crushed as finely as possible by hand and then introduced into deionized water at a temperature of 30°C in an amount 10 times that of the toner. After stirring and mixing for 30 minutes, vacuum filtration was performed again using an aspirator, and the conductivity of the filtrate was measured. This process was repeated until the conductivity of the filtrate reached a value of no more than 5 μS / cm.

[0314] The washed resin particles were finely pulverized using a wet / dry granulator and then vacuum-dried in an oven at 35° C. for 36 hours to obtain resin particles.

[0315] (Resin particle dispersion)

[0316] 400.0 parts of deionized water were introduced into a reaction vessel. A surfactant (sodium dodecylbenzenesulfonate) and a metal salt (aluminum chloride hexahydrate) were added thereto to provide a surfactant concentration of 1.0×100% by mass and a metal ion concentration of 40.0 mmol / L. 100.0 parts of resin particles were added thereto and dispersed at 5,000 rpm for 6 minutes at a temperature of 25°C using a homogenizer (Ultra-Turrax T50, IKA Japan KK). A 1.0N aqueous sodium hydroxide solution was then used to adjust the pH to 9.0, and a resin particle dispersion was obtained.

[0317] Then, 100.0 parts of the resin particle dispersion was measured into a reaction container and the temperature was raised to 70° C. while stirring. 18.0 parts of a hydrolyzed solution of hexyltriethoxysilane adjusted to pH 9.0 using a 1 mol / L NaOH aqueous solution was added thereto and stirred for 240 minutes to perform a condensation step.

[0318] The particles were then filtered using Kiriyama filter paper (No. 5C, pore size = 1 μm) to separate the particles from the filtrate. The obtained particles were further washed with 100 parts of deionized water and vacuum-dried at 25°C for 24 hours to obtain Toner Particles 23. Toner Particles 23 were used as they were as Toner 23. The physical properties of the obtained Toner 23 are shown in Table 3.

[0319] <Toner 24 Production Example>

[0320] <Preparation of Binder Resin Particle Dispersion 2>

[0321] 89.5 parts of styrene, 9.2 parts of butyl acrylate, 1.3 parts of acrylic acid as a monomer for providing a carboxyl group and 3.2 parts of n-lauryl mercaptan are mixed and dissolved. To this solution, 1.5 parts of an aqueous solution of Neogen RK (Dai-ichi Kogyo Seiyaku Co., Ltd.) in 150 parts of deionized water are added and dispersed. While slowly stirring for 10 minutes, an aqueous solution of 0.3 parts of potassium persulfate in 10 parts of deionized water is also added. After replacement with nitrogen, emulsion polymerization is carried out at 70°C for 6 hours. After completion of the polymerization, the reaction solution is cooled to room temperature and deionized water is added to obtain a binder resin particle dispersion 2 having a solid concentration of 12.5% ​​by mass and a median particle size of 0.2 μm based on volume. The resin contained in the binder resin particle dispersion 2 contains a carboxyl group derived from acrylic acid.

[0322] <Preparation of Release Agent Dispersion>

[0323] 100 parts of a release agent (behenyl behenate, melting point: 72.1° C.) and 15 parts of Neogen RK were mixed in 385 parts of deionized water and dispersed for about 1 hour using a JN100 wet jet mill (JOKOH Co., Ltd.) to obtain a release agent dispersion. The concentration of the release agent dispersion was 20% by mass.

[0324] <Preparation of Colorant Dispersion>

[0325] A colorant dispersion was obtained by mixing 100 parts of a copper phthalocyanine pigment (Pigment Blue 15:3) as a colorant and 15 parts of Neogen RK into 885 parts of deionized water and dispersing for about 1 hour using a JN100 wet jet mill.

[0326] Then, a homogenizer (Ultra-Turrax T50, IKA) was used to disperse 265 parts of binder resin particle dispersion 2, 10 parts of release agent dispersion and 10 parts of colorant dispersion. While stirring, the temperature in the container was adjusted to 30°C and the pH was adjusted to 8.0 (pH adjustment 1) by adding a 1 mol / L sodium hydroxide aqueous solution. While stirring at 30°C, an aqueous solution of 0.3 parts of calcium chloride dissolved in 10 parts of deionized water was added as an aggregating agent over 10 minutes. After standing for 3 minutes, heating was started and the temperature was raised to 50°C to generate aggregated particles. In this state, the particle size of the aggregated particles was measured using "Coulter CounterMultisizer 3" (registered trademark, Beckman Coulter, Inc.). When the weight-average particle size reached 6.5 μm, 0.9 parts of sodium chloride and 5.0 parts of Neogen RK were added to stop particle growth.

[0327] 1.0 part of calcium chloride was added as a supplementary metal compound, followed by 14.0 parts of the organosilicon compound hexyltriethoxysilane. The mixture was adjusted to pH 9.0 by adding a 1 mol / L aqueous sodium hydroxide solution (pH adjustment 2), and then heated to 95°C. While stirring at 95°C, hydrolysis and condensation of the organosilicon compound proceeded, while fusion and spheroidization of the aggregated particles proceeded. Cooling was initiated when the average circularity reached 0.980; after cooling to 85°C, pH was adjusted to pH 9.5 by adding a 1 mol / L aqueous sodium hydroxide solution (pH adjustment 3); stirring was continued for 180 minutes to further promote condensation; and cooling was then performed to obtain a toner particle dispersion.

[0328] A toner filter cake was obtained by adding hydrochloric acid to the resulting toner particle dispersion to adjust the pH to no more than 1.5, allowing the mixture to stand for one hour while stirring, and then subjecting the toner particle dispersion to solid-liquid separation on a pressurized filter. The toner filter cake was re-dispersed with deionized water to a dispersion, followed by solid-liquid separation on the filter. Reslurrying and solid-liquid separation were repeated until the filtrate's electrical conductivity reached no more than 5.0 μS / cm, after which a final solid-liquid separation was performed to obtain the toner filter cake. The resulting toner filter cake was dried in a Flash Jet Dryer (Seishin Enterprise Co., Ltd.). Drying conditions included an inlet temperature of 90°C and a dryer outlet temperature of 40°C. The toner filter cake feed rate was adjusted to a rate that maintained the outlet temperature at 40°C, depending on the water content of the toner filter cake. Fine and coarse particles were separated using a multi-stage classifier based on the Coanda effect to obtain toner particles 24. The toner particles 24 were used as they were as toner 24. The physical properties of the obtained toner 24 are shown in Table 3.

[0329] [Table 1]

[0330]

[0331] [Table 2-1]

[0332]

[0333] [Table 2-2]

[0334]

[0335] [Table 3]

[0336]

[0337] *1: Ratio of the peak area attributable to the structure having formula (T3) to the total peak area of ​​the silicone polymer

[0338] *2: Ratio of Arn line segments with FRAn not exceeding 5.0nm

[0339] *3: Ratio of toner particles having at least one inorganic fine particle in contact with the core particle and not in contact with the surface layer

[0340] *4: Ratio of toner particles in which at least one inorganic fine particle is present in each of eight equally divided regions of the surface layer

[0341] *5: Ratio of toner particles in which the number of inorganic fine particles in contact with the core particles present in the surface layer is 16 to 30

[0342] <Examples 1 to 18 and Comparative Examples 1 to 6>

[0343] The following evaluations were performed on Toners 1 to 24. The evaluation results of Toners 1 to 24 are given in Table 4.

[0344] <Evaluation of Developing Roller Film Formation>

[0345] The method and evaluation criteria for evaluating filming of the developing roller are specifically described below.

[0346] For image forming apparatus, use a Figure 1 A modified machine and a modified box of a tandem laser beam printer HP ColorLaser Jet Enterprise CP4525dn (Hewlett-Packard) are provided.

[0347] The modified machine was modified by changing the internal gearing to provide a process speed of 320 mm / sec. Furthermore, the product toner was removed from the cartridge, cleaned using a blower, and then filled with 250 g of toner. The toner cartridge was left in the evaluation environment for 24 hours and then installed in the cyan station of the printer. Image output tests were conducted using dummy cartridges installed in other stations.

[0348] Output 50,000 sheets by repeating the process of printing two sheets and pausing for one minute. The toner lay-on level is 0.3 mg / cm 2 The halftone images were taken and the image evaluation was performed using the following method.

[0349] (Evaluation criteria for developing roller film formation)

[0350] The developer roller filming was evaluated by visual inspection of the developer roller surface and by evaluation of images.

[0351] After printing 25,000 and 50,000 sheets, visual evaluation was performed as to whether uneven shading occurred in the 1% printed image area and non-printed image area of ​​the printed halftone image. The toner on the surface of the developing roller was then blown away with air, and the surface of the developing roller was observed.

[0352] A: No unevenness in shading occurs in the image and no filming occurs on the developing roller surface.

[0353] B: No uneven shading occurs in the image, but some filming is observed on the developing roller surface.

[0354] C: Filming was observed on the developing roller surface and slight unevenness in shading occurred in the image.

[0355] D: Filming was observed on the developing roller surface and significant unevenness in shading occurred in the image.

[0356] <Fog evaluation>

[0357] To evaluate fogging, the same image output test as in the evaluation of developing roller filming was performed in a 30.0° C. / humidity 80.0% RH environment, and the evaluation was performed using the following method.

[0358] (Evaluation criteria for fogging)

[0359] After outputting 25,000 and 50,000 sheets, the reconstructed machine and reconstructed cartridge were placed in a 30.0°C / 80.0% RH environment for three days. Following this period, an image with a white background was output, and image fogging was evaluated by calculating the fog density (%) using the difference between the whiteness of the evaluation paper and the whiteness of the white background area of ​​the output image, as measured using a "Reflectometer Model TC-6DS" (Tokyo Denshoku Co., Ltd.). The fog density was determined by rounding off to the second decimal place. A green filter was used as the filter.

[0360] A: Fogging concentration does not exceed 0.5%

[0361] B: Fogging concentration is at least 0.6% and not more than 1.5%

[0362] C: Fogging concentration is at least 1.6% and not more than 2.5%

[0363] D: Fogging concentration is at least 2.6%

[0364] <Evaluation of Fixing Performance>

[0365] The modified machine and modified cartridge described above were operated in a normal temperature and normal humidity (25°C / 50%RH) environment, and solid images (toner load level: 0.40 mg / cm 2 Use plain paper (letter size XEROX 4200 paper, Xerox Corporation, 75g / m 2 ) as transfer material.

[0366] The fixed image was fixed using Kimwipes (S-200, Crecia Co. Ltd.) at 75 g / cm 2 The image was rubbed 10 times under a load of 1000 nm, and the low-temperature fixing property was evaluated based on the temperature at which the density drop rate before and after rubbing became less than 5% and the temperature at which the density drop rate before and after rubbing became less than 10%. The image density was measured using a reflection densitometer (product name: RD918, MacBeth Corporation).

[0367] (Evaluation Criteria)

[0368] A: not exceeding 140℃

[0369] B: 145℃

[0370] C: 150℃

[0371] D: at least 155℃

[0372] [Table 4]

[0373]

[0374] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A toner comprising toner particles, wherein the toner particles include core particles containing a binder resin, and The surface layer comprises inorganic fine particles and organosilicon polymer, characterized in that The organosilicon polymer has a structure given by the following formula (T3): R-Si(O 1 / 2 )3(T3) wherein R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group; of the tetrahydrofuran-insoluble matter in the toner particles 29 In Si-NMR measurement, the ratio of the peak area attributable to the structure given by formula (T3) relative to the total peak area of ​​the organosilicon polymer is at least 5.0%; and In observation of a cross section of the toner particles using a transmission electron microscope, The major axis L is a chord passing through the geometric center of the toner particle and having the longest diameter in the cross section of the toner particle, Line segment a is one of the line segments when the major axis L is divided at its midpoint. Arn are 32 line segments drawn from the midpoint of the major axis L to the surface of the toner particle with the line segment a as a reference and shifted by 11.25 degrees each time, where n=1 to 32. RAn is the length of each of the line segments, n = 1 to 32, and FRAn is the thickness of the surface layer on the Arn, n=1 to 32, In the cross section of the toner particles within the range of ±10% of the weight average particle size of the toner particles, Dtem defined by the following formula (1) is: (i) the average thickness Dav. of the surface layer is 5.0 to 100.0 nm, (ii) the proportion of Arn line segments with FRAn not exceeding 5.0 nm does not exceed 20.0%, (iii) the number of the inorganic fine particles in the surface layer in contact with the core particle is 16 to 30 per 1 toner particle, and (iv) among 100 toner particles having the Dtem within the range of ±10% of the weight-average particle diameter of the toner particles, the proportion of toner particles containing at least one inorganic fine particle that is present in the core particle and is not in contact with the surface layer is not more than 10%; Dtem=(RA1+RA2+RA3+RA4+RA5+RA6+RA7+RA8+RA9+RA10+RA11+RA12+RA13+RA14+RA15+RA16+RA1 7+RA18+RA19+RA20+RA21+RA22+RA23+RA24+RA25+RA26+RA27+RA28+RA29+RA30+RA31+RA32) / 16 (1)， wherein the inorganic fine particles contain at least one selected from the group consisting of calcium element and magnesium element. 2 . The toner according to claim 1 , wherein the inorganic fine particles have a primary particle diameter having a number average particle diameter Dm of 50.0 to 800.0 nm.

3. The toner according to claim 1 or 2, wherein In the observation of the cross section of the colorant particles using the transmission electron microscope, among 100 colorant particles whose Dtem is within the range of ±10% of the weight-average particle size of the colorant particles, the proportion of the colorant particles in which at least one of the inorganic fine particles is present in each of the area of ​​the surface layer sandwiched between Ar1 and Ar5, the area of ​​the surface layer sandwiched between Ar5 and Ar9, the area of ​​the surface layer sandwiched between Ar9 and Ar13, the area of ​​the surface layer sandwiched between Ar13 and Ar17, the area of ​​the surface layer sandwiched between Ar17 and Ar21, the area of ​​the surface layer sandwiched between Ar21 and Ar25, the area of ​​the surface layer sandwiched between Ar25 and Ar29, and the area of ​​the surface layer sandwiched between Ar29 and Ar1 is at least 90%.

4. The toner according to claim 1 or 2, wherein In the observation of the cross section of the colorant particles using a transmission electron microscope, among 100 colorant particles whose Dtem is within the range of ±10% of the weight-average particle size of the colorant particles, the proportion of colorant particles in which the number of inorganic fine particles in contact with the core particles in the surface layer is 16 to 30 is at least 90%.

5. The toner according to claim 1 or 2, wherein the average thickness Dav. of the surface layer and the primary particle diameter Dm of the inorganic fine particles satisfy the following formula: Dav. / Dm<1.00.

Images