TONER

Abstract

A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied:

A≤90  (I)

100≤B≤1000  (II).

Claims

1. A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied:
A≤90  (I)
100≤B≤1000  (II).

2. The toner according to claim 1, wherein the organosilicon polymer fine particle has a structure of alternately binding silicon atoms and oxygen atoms, and at least part of an organosilicon polymer in the organosilicon polymer fine particle comprises a T3 unit structure represented by R.sup.aSiO.sub.3/2, where R.sup.a is a C.sub.1-6 alkyl group or a phenyl group.

3. The toner according to claim 2, wherein in .sup.29Si-NMR measurement of the organosilicon polymer fine particle, a ratio of an area of peaks derived from silicon having the T3 unit structure relative to a total area of peaks derived from all silicon element contained in the organosilicon polymer fine particle is 0.50 to 1.00.

4. The toner according to claim 1, wherein the alumina particle has a circularity of 0.70 to 0.99.

5. The toner according to claim 1, wherein an average projected area of the composite particle is 0.01 to 1.00 μm.sup.2.

6. The toner according to claim 1, wherein a number ratio of the composite particle relative to the toner particle is at least 0.1.

7. The toner according to claim 1, wherein the content of the composite particle is from 0.01 to 3.00 mass parts per 100 mass parts of the toner particle.

Description

EXAMPLES

[0214] The invention is explained in more detail below based on examples and comparative examples, but the invention is in no way limited to these. Unless otherwise specified, parts in the examples are based on mass.

[0215] Toner manufacturing examples are explained.

Preparation of Binder Resin Particle Dispersion

[0216] 89.5 parts of styrene, 9.2 parts of butyl acrylate, 1.3 parts of acrylic acid and 3.2 parts of n-lauryl mercaptane were mixed and dissolved. An aqueous solution of 1.5 parts of Neogen RK (DKS Co., Ltd.) in 150 parts of ion-exchange water was added and dispersed in this mixed solution.

[0217] This was then gently stirred for 10 minutes as an aqueous solution of 0.3 parts of potassium persulfate mixed with 10 parts of ion-exchange water was added.

[0218] After nitrogen purging, emulsion polymerization was performed for 6 hours at 70° C. After completion of polymerization, the reaction solution was cooled to room temperature, and ion-exchange water was added to obtain a binder resin particle dispersion with a volume-based median particle diameter of 0.2 μm and a solids concentration of 12.5 mass %.

[0219] Preparation of Release Agent Dispersion 100 parts of a release agent (behenyl behenate, melting point: 72.1° C.) and 15 parts of Neogen RK were mixed with 385 parts of ion-exchange water, and dispersed for about 1 hour with a JN100 wet jet mill (Jokoh Co., Ltd.) to obtain a release agent dispersion. The solids concentration of the release agent dispersion was 20 mass %.

[0220] Preparation of Colorant Dispersion

[0221] 100 parts of carbon black “Nipex35 (Orion Engineered Carbons)” and 15 parts of Neogen RK were mixed with 885 parts of ion-exchange water, and dispersed for about 1 hour in a JN100 wet jet mill to obtain a colorant dispersion.

[0222] Preparation of Toner Particle 1

[0223] 265 parts of the binder resin particle dispersion, 10 parts of the release agent dispersion and 10 parts of the colorant dispersion were dispersed with a homogenizer (IKA Japan K.K.: Ultra-Turrax T50).

[0224] The temperature inside the vessel was adjusted to 30° C. under stirring, and 1 mol/L hydrochloric acid was added to adjust the pH to 5.0. This was left for 3 minutes before initiating temperature rise, and the temperature was raised to 50° C. to produce aggregate particles. The particle diameter of the aggregate particles was measured under these conditions with a “Multisizer 3 Coulter Counter” (registered trademark, Beckman Coulter, Inc.). Once the weight-average particle diameter reached 6.2 μm, 1 mol/L sodium hydroxide aqueous solution was added to adjust the pH to 8.0 and arrest particle growth.

[0225] The temperature was then raised to 95° C. to fuse and spheroidize the aggregate particles. Temperature lowering was initiated when the average circularity reached 0.980, and the temperature was lowered to 30° C. to obtain a toner particle dispersion 1.

[0226] Hydrochloric acid was added to adjust the pH of the resulting toner particle dispersion 1 to 1.5 or less, and the dispersion was stirred for 1 hour, left standing, and then subjected to solid-liquid separation in a pressure filter to obtain a toner cake.

[0227] This was made into a slurry with ion-exchange water, re-dispersed, and subjected to solid-liquid separation in the previous filter unit. Re-slurrying and solid-liquid separation were repeated until the electrical conductivity of the filtrate was not more than 5.0 μS/cm, to perform final solid-liquid separation and obtain a toner cake.

[0228] The resulting toner cake was dried with a Flash Jet air dryer (Seishin Enterprise Co., Ltd.). The drying conditions were a blowing temperature of 90° C. and a dryer outlet temperature of 40° C., with the toner cake supply speed adjusted according to the moisture content of the toner cake so that the outlet temperature did not deviate from 40° C. Fine and coarse powder was cut with a multi-division classifier using the Coanda effect, to obtain a toner particle 1. The toner particle 1 had a weight-average particle diameter (D4) of 6.3 μm, an average circularity of 0.980, and a glass transition temperature (Tg) of 57° C.

[0229] Manufacturing Example of Organosilicon Polymer Fine Particle A1

Step 1

[0230] 360.0 parts of water were placed in a reactor equipped with a thermometer and a stirrer, and 15.0 parts of 5.0 mass % hydrochloric acid were added to obtain a uniform solution. This was stirred at 25° C. as 136.0 parts of methyl trimethoxysilane were added and stirred for 5 hours, after which the mixture was filtered to obtain a clear reaction solution containing a silanol compound or a partial condensate thereof

Step 2

[0231] 440.0 parts of water were placed in a reactor equipped with a thermometer, a stirrer and a dripping mechanism, and 15.0 parts of 10.0 mass % ammonia water were added to obtain a uniform solution.

[0232] This was stirred at 40° C. as 100.0 parts of the reaction solution obtained in Step 1 were dripped in over the course of 1.00 hours, and then stirred for 6 hours to obtain a suspension.

[0233] The resulting suspension was centrifuged to precipitate the particles, which were then removed and dried for 24 hours in a drier at 200° C. to obtain an organosilicon polymer fine particle A1.

[0234] The number-average particle diameter of the primary particles of the resulting organosilicon polymer fine particle A1 was 50 nm.

[0235] Manufacturing Examples of Organosilicon Polymer Fine Particles A2 to A6

[0236] Organosilicon polymer fine particles A2 to A6 were obtained as in the manufacturing example of the organosilicon polymer fine particle A1 except that the silane compound, reaction initiation temperature, added amount of ammonia water and reaction solution dripping time were changed as shown in Tables 1-1 and 1-2. The physical properties of the resulting organosilicon polymer fine particles A2 to A6 are shown in Tables 1-1 and 1-2.

TABLE-US-00002 TABLE 1-1 First Step Organosilicon Hydrochloric Reaction polymer fine Water acid temperature Silane compound A Silane compound B Silane compound C particle No. Parts Parts ° C. Name Parts Name Parts Name Parts A1 360.0 15.0 25 Methyl 136.0 — — — — trimethoxysilane A2 360.0 8.0 25 Pentyl 190.1 Tripentyl 5.0 — — trimethoxysilane methoxysilane A3 360.0 23.0 25 Methyl 136.0 — — — — trimethoxysilane A4 360.0 15.0 25 Methyl 122.4 Trimethyl 10.4 — — trimethoxysilane methoxysilane A5 360.0 13.0 25 Methyl 122.4 Trimethyl 10.4 Tetramethoxysilane 7.6 trimethoxysilane methoxysilane A6 360.0 20.0 25 Methyl 136.0 — — — — trimethoxysilane

TABLE-US-00003 TABLE 1-2 Number- Second Step average Organo- Reaction particle silicon solution diameter polymer obtained Reaction of fine in Ammonia start Dripping primary particle first step Water water temperature time particles No. Parts Parts Parts ° C. h [nm] T A1 100 440 15.0 40 1.00 50 1.00 A2 100 440 10.0 40 2.00 20 0.98 A3 100 440 17.0 35 0.60 90 1.00 A4 100 440 15.0 40 1.00 50 0.90 A5 100 440 15.0 40 1.00 50 0.88 A6 100 500 23.0 30 0.17 350 1.00

[0237] In the Tables 1-1 and 1-2, T represents the ratio of the area of peaks derived from silicon having a T3 unit structure to the total area of peaks derived from all silicon element contained in the organosilicon polymer fine particles.

[0238] Examples of Alumina Particle

[0239] The alumina particle is explained.

[0240] The alumina particles shown in Table 2 were used. The physical properties of the alumina particles 1 to 10 are shown in Table 2. The alumina particles 4 to 6 were prepared by the following manufacturing methods.

[0241] The surfaces of the alumina particles 1 to 5 and 7 to 10 are untreated. The surface of the alumina particle 6 has been treated with calcium stearate.

[0242] Manufacturing Example of Alumina Particle 4

[0243] An alumina particle 2 with a number-average particle diameter of 150 nm (AKP-53, Sumitomo Chemical Co., Ltd.) was dispersed in a solution, centrifuged to remove coarse particles, and then dried to obtain an alumina particle 4 with a number-average particle diameter of 100 nm. The physical properties of the alumina particle 4 are shown in Table 2.

[0244] Manufacturing Example of Alumina Particle 5

[0245] An air classifier was used to remove fine particles from an alumina particle 3 with a number-average particle diameter of 590 nm (AA-07, Sumitomo Chemical Co., Ltd.) and obtain an alumina particle 5 with a number-average particle diameter of 950 nm. The physical properties of the alumina particle 5 are shown in Table 2.

[0246] Manufacturing Example of Alumina Particle 6

[0247] An alumina particle with a number-average particle diameter of 240 nm (AES-11, Sumitomo Chemical Co., Ltd.) was surface treated with 0.5 mass % calcium stearate to obtain an alumina particle 6.

[0248] The physical properties of the alumina particle 6 are shown in Table 2.

TABLE-US-00004 TABLE 2 Number-average diameter of Alumina Product name primary particles particle No. (manufacturer) Surface treatment (nm) Circularity 1 AA-04 (Sumitomo — 400 0.79 Chemical Co., Ltd.) 2 AKP-53 (Sumitomo — 150 0.76 Chemical Co., Ltd.) 3 AA-07 (Sumitomo — 590 0.79 Chemical Co., Ltd.) 4 Centrifuged alumina — 100 0.82 particle 2 5 Air-classified alumina — 950 0.75 particle 3 6 AES-11 (Sumitomo Calcium stearate 240 0.65 Chemical Co., Ltd.) 7 TM5D (Taimei Chemicals — 230 0.98 Co., Ltd.) 8 AO-509 (Admatechs Co.) — 800 0.98 9 Alu-C (Nippon Aerosil Co., — 15 0.72 Ltd.) 10 AA-15 (Sumitomo — 1400 0.78 Chemical Co., Ltd.)

[0249] Manufacturing Example of Composite Particle 1

[0250] The organosilicon polymer fine particle A1 and the alumina particle 1 were mixed in a 500 ml glass vessel in the proportions shown in Table 3, and then mixed for 1 minute with a blender-mixer (Oster Co.) at an output of 450 W to obtain a composite particle 1.

[0251] Manufacturing Examples of Composite Particles 2 to 19

[0252] Composite particles 2 to 19 were obtained as in the manufacturing example of the composite particle 1 except that the conditions were changed as shown in Table 3.

[0253] Manufacturing Example of Composite Particle 20

[0254] A composite particle 20 was obtained as in the manufacturing example of the composite particle 1 except that 8 parts of a sol-gel silica with a number-average particle diameter of 110 nm (X24-9600A, Shinetsu Chemical Co., Ltd.) were used instead of the 3.5 parts of the organosilicon polymer fine particle A1.

TABLE-US-00005 TABLE 3 Organosilicon polymer fine Alumina particle particle Composite Particle Particle particle diameter diameter No. No. (nm) Parts No. (nm) Parts 1 A1 50 3.5 1 400 1.0 2 A1 50 5.0 1 400 1.0 3 A3 90 7.0 2 150 1.0 4 A3 90 10.0 2 150 1.0 5 A3 90 12.0 2 150 1.0 6 A2 20 0.05 3 590 1.0 7 A2 20 0.1 3 590 1.0 8 A2 20 0.7 3 590 1.0 9 A4 50 3.5 1 400 1.0 10 A5 50 3.5 1 400 1.0 11 A1 50 12.0 4 100 1.0 12 A1 50 0.6 5 950 1.0 13 A1 50 2.5 6 240 1.0 14 A1 50 2.5 7 230 1.0 15 A1 50 0.8 8 800 1.0 16 A1 20 0.8 1 400 1.0 17 A3 90 100.0 9 15 1.0 18 A3 90 1.0 10 1400 1.0 19 A6 350 3.0 3 590 1.0

[0255] Manufacturing Example of Toner 1

External Addition Step

[0256] 0.30 parts of the composite particle 1 and 1.00 part of a hydrophobic silica fine particle [shown as C1 in the table, BET specific surface area 300 m.sup.2/g, hydrophobically treated with 30 parts of hexamethyl disilazane (HMDS) and 10 parts of dimethyl silicone oil per 100 parts of the silica fine particle) were added to 100.00 parts of the resulting toner particle 1 in an FM mixer (FM10C, Nippon Coke and Engineering Co., Ltd.) with 7° C. water flowing through the jacket.

[0257] Once the water temperature in the jacket had stabilized at 7° C.±1° C., this was mixed for 5 minutes with the peripheral speed of the rotating blade at 38 m/sec to obtain a toner mixture 1. The amount of water flowing through the jacket was adjusted appropriately during this process so that the internal tank temperature of the FM mixer did not exceed 25° C. The resulting toner mixture 1 was sieved with a 75 μm mesh to obtain a toner 1.

[0258] The toner manufacturing conditions and the physical properties of the toner are shown in Table 4. The coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle in the composite particle, the average projected area of the composite particle and the number ratio of composite particles relative to toner particles were also measured in the resulting toner. The results are shown in Table 4.

[0259] Preparation Examples of Toners 2 to 19 and Comparative Toners 1 to 7

[0260] Toners 2 to 19 and comparative toners 1 to 7 were obtained as in the manufacturing example of the toner 1 except that the conditions were changed as shown in Table 4. The physical properties of the toners 2 to 19 and comparative toners 1 to 7 are shown in Table 4.

TABLE-US-00006 TABLE 4 Physical properties of External addition conditions composite particle Example Toner Additive Additive X Y No. No. Additive 1 Parts 2 Parts 3 Parts (area %) (μm.sup.2) Z 1 1 Composite particle 1 0.30 C1 1.00 — — 32 0.30 2 2 2 Composite particle 2 0.30 C1 1.00 — — 50 0.32 2 3 3 Composite particle 3 0.30 C1 1.00 — — 25 0.10 12 4 4 Composite particle 4 0.30 C1 1.00 — — 34 0.10 11 5 5 Composite particle 5 0.30 C1 1.00 — — 44 0.12 11 6 6 Composite particle 6 0.30 C1 1.00 — — 2 0.45 0.4 7 7 Composite particle 7 0.30 C1 1.00 — — 5 0.43 0.5 8 8 Composite particle 8 0.30 C1 1.00 — — 45 0.48 0.4 9 9 Composite particle 9 0.30 C1 1.00 — — 32 0.32 2 10 10 Composite particle 10 0.30 C1 1.00 — — 34 0.30 2 11 11 Composite particle 11 0.30 C1 1.00 — — 34 0.05 50 12 12 Composite particle 12 0.30 C1 1.00 — — 28 0.62 0.2 13 13 Composite particle 13 0.30 C1 1.00 — — 20 0.15 5 14 14 Composite particle 14 0.30 C1 1.00 — — 20 0.18 4 15 15 Composite particle 15 0.30 C1 1.00 — — 24 0.60 0.3 16 16 Composite particle 1 0.10 C1 1.00 — — 35 0.30 0.9 17 17 Composite particle 1 0.30 C1 1.00 — — 35 0.30 3 18 18 Composite particle 1 0.50 C1 1.00 — — 35 0.30 4 19 19 Composite particle 1 0.70 C1 1.00 — — 35 0.30 6 C.E. 1 C. 1 Composite particle 16 0.30 C1 1.00 — — 58 0.32 0.8 C.E. 2 C. 2 Composite particle 17 0.30 C1 1.00 — — 88 0.08 50 C.E. 3 C. 3 Composite particle 18 0.30 C1 1.00 — — 35 0.80 0.1 C.E. 4 C. 4 Composite particle 19 0.30 C1 1.00 — — 26 0.42 0.5 C.E. 5 C. 5 Composite particle 20 0.30 C1 1.00 — — 32 0.16 5 C.E. 6 C. 6 Alumina particle 1 0.30 C1 1.00 — — — — — C.E. 7 C. 7 Alumina particle 2 0.30 A3 0.3 C1 1.00 0 — 0

[0261] In the table, “C.E.” represents “Comparative Example”, “C.” represents “Comparative”, X represents the coverage ratio (area %) of the alumina particle surface by the organosilicon polymer fine particle, Y represents the average projected area of the composite particle, Z represents the number ratio of composite particles relative to toner particles, and A3 is the organosilicon polymer fine particle A3.

Example 1

[0262] The toner 1 was evaluated as follows. The evaluation results are shown in Table 5.

[0263] A modified LBP 712Ci (Canon) was used as the apparatus for evaluation. The process speed of the main unit was modified to 300 mm/sec. Under these conditions, the necessary adjustments were made to make image formation possible. The toner was also removed from the black cartridge, which was then filled with 200 g of the toner 1.

[0264] Image Evaluation

(1) Fogging on Drum

[0265] To test the charging stability of the toner, fogging (HH fogging) in a high-temperature high-humidity environment (30° C./80% RH) and fogging (LL fogging) in a low-temperature low-humidity environment (15° C./10% RH) were evaluated by the following methods.

[0266] 2,000 sheets per day of an image with a print percentage of 1.0% were output on Canon color laser copy paper (A4: 81.4 g/m.sup.2, also used below unless otherwise specified) in each environment with a pause of 2 seconds after every 2 sheets, for a total of 20,000 sheets. Fogging on the drum in the cartridge was collected by taping and evaluated at the beginning, after 10,000 sheets and after 20,000 sheets of output.

[0267] Fogging was measured with a reflection densitometer (Tokyo Denshoku, Reflectometer Model TC-6DS). The worst value of the white background reflection of the taped part was given as Ds and the average value of the reflection density of the taped part of the paper was given as Dr, and (Ds−Dr) was given as the fogging density (%). A green filter was used as the filter. Evaluation was performed using the following evaluation standard. In this evaluation method, fogging density on the drum increases as the charging performance of the toner declines.

Fogging

[0268] Evaluation Standard

[0269] A: Fogging density less than 0.5%

[0270] B: Fogging density at least 0.5% to less than 2.0%

[0271] C: Fogging density at least 2.0% to less than 4.0%

[0272] D: Fogging density at least 4.0%

(2) Solid Image Followability

[0273] To test the flowability and durability of the toner, solid image followability was evaluated in a high-temperature high-humidity environment (30° C./80% RH, HH). 2,000 sheets per day of an image with a print percentage of 1.0% were output on Canon color laser copy paper in a high-temperature high-humidity environment (30° C./80% RH) with a pause of 2 seconds after every 2 sheets, for a total of 20,000 sheets.

[0274] Three sheets of an all-solid image were output continuously as sample images using the cartridge at the beginning, after 10,000 sheets and after 20,000 sheets of output. The resulting three all-solid images were evaluated visually for solid image followability. This evaluation yields better results the greater the flowability of the toner.

Solid Image Followability

[0275] Evaluation Standard

[0276] A: Image density uniform without irregularities

[0277] B: Some irregularities in image density

[0278] C: Image density with irregularities but still good

[0279] D: Image density with irregularities, uniform solid image not obtained

(3) LL Charging Roller Contamination

[0280] To test the degree of wear and contamination of the key parts by the toner, charging roller contamination was evaluated by the following method. 2,000 sheets per day of an image with a print percentage of 1.0% were output on Canon color laser copy paper in a low-temperature low-humidity environment (15° C./10% RH, LL) with a pause of 2 seconds after every 2 sheets, for a total of 20,000 sheets of output.

[0281] The charging roller was then removed from the toner cartridge, the charging roller was removed from a new (commercial) process cartridge and replaced with the above charging roller after 20,000 sheets of output, and a halftone image was output. The uniformity of the halftone image was evaluated visually to evaluate charging roller contamination. Because charging roller contamination is likely when there is wear to the photosensitive body or the cleaning blade, this evaluation is lower the greater the degree of wear and contamination of the key parts by the toner.

Charging Member Contamination

[0282] Evaluation Standard

[0283] A: Image density uniform with no irregularities

[0284] B: Some irregularities in image density

[0285] C: Image density with irregularities but still good

[0286] D: Image density with irregularities, uniform solid image not obtained

Examples 2 to 19, Comparative Examples 1 to 7

[0287] The same evaluations in Example 1 were performed using the toners 2 to 19 and the comparative toners 1 to 7. The evaluation results are shown in Table 5.

TABLE-US-00007 TABLE 5 LL charging roller HH solid image contami- HH fogging LL fogging followability nation After After After After After After Toner 10000 20000 10000 20000 10000 20000 Example No. Initial sheets sheets Initial sheets sheets Initial sheets sheets 1 1 0.3 A 0.4 A 0.3 A 0.3 A 0.3 A 0.3 A A A A A 2 2 0.3 A 0.3 A 0.8 B 0.3 A 0.3 A 0.4 A A A A A 3 3 0.3 A 0.3 A 0.3 A 0.3 A 0.3 A 0.3 A A A A B 4 4 0.3 A 0.4 A 0.3 A 0.3 A 0.3 A 0.3 A A A A B 5 5 0.3 A 0.4 A 0.4 A 0.3 A 0.3 A 0.4 A A A A B 6 6 0.3 A 0.3 A 0.3 A 0.3 A 0.3 A 1.2 B A A B A 7 7 0.4 A 0.3 A 0.4 A 0.4 A 0.3 A 0.3 A A A A A 8 8 0.3 A 0.4 A 0.3 A 0.3 A 0.4 A 0.4 A A A A A 9 9 0.3 A 0.3 A 0.4 A 0.3 A 1.3 B 2.3 C A B C A 10 10 0.4 A 0.3 A 0.3 A 0.3 A 1.5 B 2.5 C A B C A 11 11 0.3 A 0.7 B 0.9 B 0.3 A 1.2 B 1.7 B A A A A 12 12 0.3 A 0.3 A 0.3 A 0.4 A 0.3 A 0.3 A A B B B 13 13 0.3 A 0.3 A 0.4 A 0.3 A 0.3 A 0.3 A A B C A 14 14 0.4 A 0.4 A 0.4 A 0.3 A 0.3 A 0.3 A A A A C 15 15 0.4 A 0.3 A 0.3 A 0.3 A 0.3 A 0.3 A A A A C 16 16 0.3 A 0.3 A 0.3 A 0.3 A 0.3 A 0.3 A A A A A 17 17 0.3 A 0.4 A 0.4 A 0.3 A 0.4 A 0.3 A A A A A 18 18 0.3 A 0.4 A 0.3 A 0.3 A 0.4 A 0.3 A A A B B 19 19 0.3 A 0.4 A 0.3 A 0.3 A 0.3 A 0.3 A A A B C C.E. 1 C. 1 0.3 A 2.2 C 4.3 D 0.3 A 3.1 C 5.3 D A A A A C.E. 2 0.2 0.3 A 3.2 C 6.1 D 0.3 A 2.8 C 4.2 D A A A D C.E. 3 0.3 0.3 A 0.3 A 0.4 A 0.3 A 0.3 A 0.3 A A C D D C.E. 4 0.4 0.3 A 0.6 B 3.9 C 0.4 A 1.1 B 2.8 C A C C D C.E. 5 0.5 0.3 A 2.5 C 3.4 C 0.3 A 1.6 B 3.1 C A B C D C.E. 6 0.6 0.3 A 0.3 A 0.4 A 0.3 A 0.4 A 0.3 A A C D D C.E. 7 0.7 0.3 A 0.4 A 0.3 A 0.3 A 0.4 A 0.3 A A C D D

[0288] In the table, “C.E.” represents “Comparative Example”, “C.” represents “Comparative”.

[0289] Good results were obtained for Examples 1 to 19 in all evaluation items. However, poor results were obtained for Comparative Examples 1 to 7 in some evaluation items. These results show that the present disclosure can provide a toner having excellent flowability and charging stability during long-term durable use with little wear or contamination to the key parts of the image-forming apparatus.

[0290] 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. This application claims the benefit of Japanese Patent Application No. 2020-107074, filed Jun. 22, 2020, which is hereby incorporated by reference herein in its entirety.