Toner

Abstract

A toner having an adequate storage stability and adequately suppressing an ejected paper adhesion, while achieving improving low-temperature fixability, has a toner particle containing a binder resin and a plasticizer, wherein Tg1 is 53° C. or lower and Tg2 is 55° C. or higher, in DSC measurement using the toner as a sample, when the following steps (i) to (iii) are performed: (i): the temperature of the toner is raised for the first time at a rate of temperature increase of 10° C./min, (ii): after the step (i), the temperature of the toner is lowered at a rate of temperature decrease of 10° C./min, (iii): after the step (ii), the temperature of the toner is raised for the second time at a rate of temperature increase of 10° C./min, Tg1 represents a glass transition temperature measured at the step (i), and Tg2 represents a glass transition temperature measured at the step (iii).

Claims

1. A toner, comprising: a toner particle comprising a binder resin, an aliphatic hydrocarbon-based wax as a solo wax and a plasticizer; the binder resin being a polyester resin; and the plasticizer consisting of at least one of an imidazolium salt and an ammonium salt, wherein when steps (i) to (iii) are performed in DSC measurement using the toner as a sample (i) the temperature of the toner is raised for a first time at a rate of 10° C./min, (ii) after step (i), the temperature of the toner is lowered at a rate of 10° C./min, (iii) after step (ii), the temperature of the toner is raised for a second time at a rate of 10° C./min, Tg1 is 53° C. or lower and Tg2 is 55° C. or higher, when Tg1 represents a glass transition temperature measured at step (i), and Tg2 represents a glass transition temperature measured at step (iii).

2. The toner according to claim 1, wherein Tg1 is 40° C. or higher.

3. The toner according to claim 1, wherein Tg2 is 70° C. or lower.

4. The toner according to claim 1, wherein the plasticizer has a melting point of 60 to 150° C.

5. The toner according to claim 1, wherein the plasticizer is represented by formula (1) ##STR00005## where R.sub.1 represents hydrogen or a methyl group, R.sub.2 and R.sub.3 independently represent an alkyl group having 1 to 4 carbon atoms or a benzyl group, and X.sup.− represents a counter anion.

6. The toner according to claim 1, wherein the plasticizer is represented by formula (2) ##STR00006## where R.sub.1 to R.sub.4 independently represent an alkyl group having 4 to 6 carbon atoms, and X.sup.− represents a counter anion.

7. The toner according to claim 1, comprising 3 to 15% by mass of the plasticizer.

8. A toner, comprising: a toner particle comprising a binder resin and a plasticizer; the binder resin being a polyester resin; and the plasticizer comprising an imidazolium salt or an ammonium salt, wherein when steps (i) to (iii) are performed in DSC measurement using the toner as a sample (i) the temperature of the toner is raised for a first time at a rate of 10° C./min, (ii) after step (i), the temperature of the toner is lowered at a rate of 10° C./min, (iii) after step (ii), the temperature of the toner is raised for a second time at a rate of 10° C./min, the binder resin and the imidazolium salt or the ammonium salt dissolve each other whereby Tg1 is 53° C. or lower, when Tg1 represents a glass transition temperature measured at step (i), and the binder resin and the imidazolium salt or the ammonium salt cause phase separation whereby Tg2 is 55° C. or higher, when Tg2 represents a glass transition temperature measured at step (iii).

Description

EXAMPLES

(1) The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples. Note that all the parts and % in Examples and Comparative Examples are based on mass, unless there is particular notice.

(2) <Production Example of Binder Resin 1>

(3) TABLE-US-00001 Propylene oxide adduct of bisphenol A 30 mol % (Average number of added moles: 2.2 mol) Ethylene oxide adduct of bisphenol A 20 mol % (Average number of added moles: 2.2 mol) Terephthalic acid 42 mol % Trimellitic anhydride  8 mol %

(4) The above monomers and dibutyltin oxide in an amount of 0.03 parts were added to 100 parts in total of the acid components, the mixture was subjected to a reaction while being stirred at 220° C. for 6 hours under a nitrogen stream, and a binder resin 1 was obtained. A glass transition temperature (Tg) of the obtained binder resin 1 was 60° C.

(5) <Production Examples of Binder Resins 2 to 4>

(6) Binder resins 2 to 4 were obtained according to the Production Example of the binder resin 1, except that the Tg of the binder resin was changed as shown in Table 1.

(7) TABLE-US-00002 TABLE 1 Binder resin No. Tg (° C.) 1 60 2 65 3 57 4 55

(8) <Production Example of Binder Resin 5>

(9) TABLE-US-00003 Styrene 80 parts /n-Butyl acrylate 20 parts /2,2′-Azobis(2,4-dimethylvaleronitrile) 0.2 parts 

(10) The above raw materials were added dropwise into 200 parts of heated xylene over 4 hours. Furthermore, the polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure. Thus obtained resin is determined as a binder resin 5. A glass transition temperature (Tg) of the obtained binder resin 5 was 55° C.

(11) <Production Example of Crystalline Polyester 1>

(12) Into a reaction vessel equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 100.0 mol parts of 1,10-decanedicarboxylic acid was charged as a carboxylic acid monomer, and 100.0 mol parts of 1,9-nonanediol was charged as an alcohol monomer. The temperature was raised to 140° C. while the mixture was stirred, and the mixture was heated to 140° C. under a nitrogen atmosphere, and was subjected to a reaction for 8 hours under normal pressure while water was distilled off. Subsequently, 0.57 parts of tin dioctylate were added, and then the mixture was subjected to a reaction while the temperature was raised to 200° C. at 10° C./hour. Furthermore, the mixture was subjected to the reaction for 2 hours after having reached 200° C., the pressure in the inside of the reaction tank was reduced to 5 kPa or less, and the mixture was subjected to the reaction at 200° C. while the molecular weight was checked, and a crystalline polyester 1 was obtained. A melting point of the crystalline polyester 1 was 75° C.

Example 1

(13) (Production Example of toner 1)

(14) TABLE-US-00004 Binder resin 1 81 parts  1,2,3-Trimethylimidazolium methylsulfate 9 parts (1,2,3-Trimethylimidazolium methylsulfate) (plasticizer; melting point of 113° C.) Normal paraffin wax (melting point: 78° C.) 6 parts C.I. Pigment Blue 15:3 4 parts

(15) The above materials were premixed by a Henschel mixer, and then the mixture was melted and kneaded at 160° C. by a twin-screw kneading extruder.

(16) The obtained kneaded product was cooled, was coarsely pulverized by a hammer mill, and then was finely pulverized by a turbo mill.

(17) The obtained finely pulverized product was classified with the use of a multi-division classifier which used the Coanda effect, and toner particles were obtained which were negatively triboelectrically charged and had a weight average particle size (D4) of 6.0 μm.

(18) To 100 parts of the toner particles, 3.5 parts of fine particles of hydrophobized silica (of which specific surface area by nitrogen adsorption measured by BET method was 140 m.sup.2/g) and 0.5 parts of fine particles of titanium oxide (rutile type, and of which specific surface area by nitrogen adsorption measured by BET method was 70 m.sup.2/g) were externally added and mixed, then the mixture was sieved by a mesh having a mesh opening of 150 μm, and a toner 1 was obtained. A Tg1 of the toner 1 was 49° C. and a Tg2 thereof was 60° C.

(19) (Production Example of Magnetic Core Particle)

(20) TABLE-US-00005 Fe.sub.2O.sub.3 62.7 parts MnCO.sub.3 29.5 parts Mg(OH).sub.2 6.8 parts SrCO.sub.3 1.0 part

(21) Ferrite of a raw material was weighed so that the above materials became the above composition ratios.

(22) After that, the materials were pulverized and mixed for 5 hours in a dry vibration mill which used stainless steel beads having a diameter of ⅛ inches. The obtained pulverized product was formed into a pellet of approximately 1 mm square with the use of a roller compactor.

(23) Coarse powders in the pellets were removed by a vibrating sieve having a mesh opening of 3 mm, subsequently fine powders were removed by a vibrating sieve having a mesh opening of 0.5 mm, then the resultant pellets were fired at a temperature of 1000° C. for 4 hours under a nitrogen atmosphere (oxygen concentration of 0.01% by volume), with the use of a burner type firing furnace, and calcined ferrite was produced. A composition of the obtained calcined ferrite was as follows:
(MnO).sub.a(MgO).sub.b(SrO).sub.c(Fe.sub.2O.sub.3).sub.d

(24) wherein a=0.257, b=0.117, c=0.007 and d=0.393.

(25) The calcined ferrite was pulverized into approximately 0.3 mm by a crusher, 30 parts of water was added to 100 parts of the calcined ferrite, and the resultant ferrite was pulverized for 1 hour by a wet ball mill which used zirconia beads having a diameter of ⅛ inches. Furthermore, the obtained slurry was pulverized for 4 hours by a wet ball mill which used alumina beads having a diameter of 1/16 inches, and a ferrite slurry (finely pulverized product of calcined ferrite) was obtained.

(26) To the ferrite slurry, 1.0 part of ammonium polycarboxylate with respect to 100 parts of calcined ferrite was added as a dispersion agent, and 2.0 parts of polyvinyl alcohol was added as a binder; and the resultant mixture was granulated into spherical particles by a spray dryer (manufacturer: Okawara Kakohki Co. Ltd.). After the particle size of the obtained particles was adjusted, the resultant particles were heated at 650° C. for 2 hours with the use of a rotary kiln, and organic components in the dispersion agent and in the binder were removed.

(27) In order to control the firing atmosphere, the temperature of the resultant particles was raised from room temperature to 1300° C. under a nitrogen atmosphere (oxygen concentration: 1.00 vol %) in an electric furnace in 2 hours, and then the resultant particles were fired at a temperature of 1150° C. for 4 hours. After that, the temperature was lowered to 60° C. over 4 hours, the nitrogen atmosphere was returned to the atmosphere, and the particles were taken out at a temperature of 40° C. or lower.

(28) After the aggregated particles were cracked, products with low-magnetic force were cut out by magnetic separation, the coarse particles were removed by sieving with a sieve having a mesh opening of 250 μm, and magnetic core particles were obtained of which the 50% particle size (D50) based on volume distribution was 37.0 μm.

(29) (Production Example of Coating Resin)

(30) TABLE-US-00006 Cyclohexyl methacrylate monomer 26.8% Methyl methacrylate monomer 0.2% Methyl methacrylate macromonomer 8.4%
(macromonomer having methacryloyl group at one end and weight average molecular weight of 5000)

(31) TABLE-US-00007 Toluene 31.3% Methyl ethyl ketone 31.3% Azobisisobutyronitrile 2.0%

(32) Among the above described materials, the cyclohexyl methacrylate monomer, the methyl methacrylate monomer, the methyl methacrylate macromonomer, the toluene and the methyl ethyl ketone were charged into a four-necked separable flask equipped with a reflux condenser, a thermometer, a nitrogen introduction tube and a stirrer. Nitrogen gas was introduced into the separable flask to make the inside of the flask a sufficient nitrogen atmosphere, then the flask was heated to 80° C., azobisisobutyronitrile was added thereto, the mixture was refluxed for 5 hours, and the materials were polymerized.

(33) Hexane was injected into the obtained reaction product to precipitate and deposit a copolymer.

(34) The obtained precipitate was filtered off and was dried in vacuum, and a resin was obtained.

(35) The resin in an amount of 30 parts was dissolved in a mixed solvent of 40 parts of toluene and 30 parts of methyl ethyl ketone, and a resin solution (solid content concentration of 30%) was obtained.

(36) (Preparation of Coating Resin Solution)

(37) TABLE-US-00008 Resin solution (solid content concentration of 30%) 33.3% Toluene 66.4% Carbon black (Regal 330; produced by Cabot Corporation) 0.3% (number average particle size of primary particles: 25 nm, specific surface area by nitrogen adsorption: 94 m.sup.2/g, and DBP oil absorption: 75 ml/100 g)

(38) The above materials were charged into a paint shaker, and the solid was dispersed for 1 hour with the use of zirconia beads having a diameter of 0.5 mm. The obtained dispersion liquid was filtered through a 5.0 μm membrane filter, and a coating resin solution was obtained.

(39) (Production Example of Magnetic Carrier)

(40) The above coating resin solution and magnetic core particles were charged into a vacuum degassing type kneader which was kept at room temperature (amount of charged coating resin solution was 2.5 parts in terms of resin component, with respect to 100 parts of magnetic core particles).

(41) After having been charged, the materials were stirred for 15 minutes at a rotation speed of 30 rpm. After a certain amount (80%) or more of the solvent was volatilized, the temperature of the resultant mixture was raised to 80° C. while being mixed under reduced pressure, toluene was distilled off over 2 hours, and then the mixture was cooled.

(42) A product with a low-magnetic force in the obtained magnetic carrier was separated by magnetic separation, the rest was passed through a sieve having an opening of 70 μm, and then was classified by an air classifier; and magnetic carriers were obtained of which the 50% particle size (D50) based on the volume distribution was 38.2 μm.

(43) <Production Example of Two-Component Developer 1>

(44) The toner 1 and the magnetic carrier were mixed so that the toner 1 became 10 parts with respect to 90 parts of the magnetic carrier, with the use of a V-type blender (V-10 type: Tokuju Corporation), on conditions of 0.5 s′ and a rotation time period of 5 minutes, and a two-component developer 1 was prepared.

(45) The obtained two-component developer 1 was subjected to the following evaluation.

(46) [Evaluation of Low-Temperature Fixability]

(47) An altered machine of a color copying machine (trade name: image RUNNER ADVANCE C9075 PRO) manufactured by Canon Inc. was used as an image forming apparatus.

(48) The two-component developer 1 was charged in a developer container of a cyan position, and the image forming apparatus was altered so that an image could be formed in a state in which the fixing device was removed. Then, an unfixed toner image (hereinafter, unfixed image) was formed on evaluation paper. For the evaluation, plain paper GF-C104 (A4, 104 g/cm.sup.2) for color copying machines and printers (sold by Canon Marketing Japan Inc.) was used.

(49) In practice, the development conditions were appropriately adjusted so that the amount of the toner of the FFh image to be mounted on the paper became 1.2 mg/cm.sup.2, and an unfixed image of 2 cm×10 cm was formed at the position of 3 cm apart from the leading edge of the A4 vertical evaluation paper and of the center of the evaluation paper. The unfixed image was humidity-controlled for 24 hours in a low temperature and low humidity environment (temperature of 15° C./relative humidity of 10%). FFh is a value indicating 256 gradations by a hexadecimal number, where 00h is the first gradation (white background part) of 256 gradations, and FFh is the 256th gradation (solid part) of 256 gradations.

(50) Subsequently, the fixing device was taken out from the full color copying machine image RUNNER ADVANCE C 9075 PRO manufactured by Canon Inc., and a holder for a fixing test was prepared in a low temperature and low humidity environment (temperature of 15° C./relative humidity of 10%) so that a processing speed and temperatures of upper and lower fixing members could be controlled independently. The processing speed was adjusted to 350 mm/sec, and a temperature of an upper belt of the above holder for the fixing test was adjusted every 5° C. in a range of 100° C. to 200° C. In a state in which a temperature of a lower belt was fixed at 100° C., the above humidity-controlled unfixed image was passed. The fixed image which passed through the fixing device was rubbed 5 times by a reciprocation motion of a lens cleaning wiper (Dusper manufactured by Ozu Corporation) to which a load of 4.9 kPa was applied, and a point at which a rate of the density decrease of the image density between times before and after the rubbing reached 10% or lower was defined as a fixing temperature. Based on such a criterion that when the density decrease exceeding 10% occurs, the image is not fixed, the lowest set temperature of the upper belt at which a rate of the image density decrease did not exceed 10% was determined to be a low temperature fixing temperature, and the low-temperature fixability was evaluated according to the following evaluation criteria.

(51) (Evaluation Criteria: Low-Temperature FIxability) A: lower than 120° C. B: 120° C. or higher and lower than 130° C. C: 130° C. or higher and lower than 140° C. D: 140° C. or higher and lower than 150° C. E: 150° C. or higher

(52) [Evaluation of Ejected Paper Adhesion]

(53) The ejected paper adhesion was evaluated with the use of a full color copying machine imageRUNNER ADVANCE C 9075 PRO manufactured by Canon Inc.

(54) The test was conducted in a high temperature and high humidity environment (30° C. and 80% RH) which was a severe condition for the ejected paper adhesion.

(55) For evaluation, a continuous printing test was conducted for 1000 sheets on both sides of office planner A4 paper (basis weight of 68 g/m.sup.2) with the use of a test chart having a printing ratio of 6%. After that, the development conditions are adjusted so that the amount of the toner of the FFh image to be mounted on the paper becomes 1.2 mg/cm.sup.2, with the use of a highly white paper: GF-C209 (A4, basis weight of 209 g/m.sup.2, and sold by Canon Marketing Japan Co., Ltd.), as a thick paper. The fixing temperature is set at 180° C., the image is continuously printed on both sides of 1000 sheets, the sheets are left on a copy receiving tray part for 1 hour in a state of being stacked, and then a state of the paper which has been peeled are evaluated. Specific evaluation criteria are as follows. A: ejected paper adhesion does not occur. B: adhesion between sheets of paper is observed, but a defect is not observed in the image when the sheets are peeled. C: a defect is observed in the image when the sheets are peeled, but the defect is not at a level which causes a practical problem. D: a noticeable defect is observed in the image when the sheets are peeled.

(56) [Evaluation of Storage Stability]

(57) A cup made from a resin (100 mL, manufactured by Sanpratec Corporation), into which 5.0 g of a toner sample was charged, was left at rest for 3 days, in a harsh environment (temperature of 50° C./relative humidity of 50%). After that, the cup was moved to a normal temperature and normal humidity environment (temperature of 23° C./relative humidity of 50%), and was left at rest overnight.

(58) As a measuring apparatus, “Powder Tester PT-X” (manufactured by Hosokawa Micron Co., Ltd.) was used, and the storage stability was evaluated with the use of a sieve with a mesh opening of 75 μm, in a normal temperature and normal humidity environment (temperature of 23° C./relative humidity of 50%). The amplitude of vibration of the sieve was adjusted so as to become 1.00 mm (peak-to-peak), the toner for evaluation was placed on the sieve, and vibration was applied for 40 seconds. After that, the storage stability was evaluated from the amount of an aggregating product of the toner which remained on the sieve, and the storage stability was evaluated according to the following evaluation criteria. A: the remaining amount of toner on the mesh is 0.20 g or less. B: the remaining amount of toner on the mesh exceeds 0.20 g and is 0.40 g or less. C: the remaining amount of toner on the mesh exceeds 0.40 g.

(59) In each of the above evaluation items, the two-component developer 1 was evaluated all as A.

Examples 2 to 8

(60) (Production Examples of Toners 2 to 8)

(61) Toners 2 to 8 were obtained in the same manner as in the Production Example of toner 1, except that the types and amounts of the binder resin and the plasticizer were changed as shown in Table 2.

(62) (Production Examples of Two-Component Developers 2 to 8)

(63) Two-component developers 2 to 8 were obtained in the same manner as in the Production Example of the two-component developer 1, except that the toners were changed as shown in Table 2. Furthermore, the two-component developers 2 to 8 were evaluated in the same manner as the two-component developer 1. The evaluation results are shown in Table 3.

(64) TABLE-US-00009 TABLE 2 Two- Binder resin Plasticizer component Binder Number Melting Number Example developer Toner resin of point of Tg1 Tg2 No. No. No. No copies Name (° C.) copies (° C.) (° C.) 1 1 1 Binder 81 1,2,3-trimethylimidazolium 113 9 49 60 resin 1 methylsulfate 2 2 2 Binder 81 tetrabutylammonium 80 9 49 60 resin 1 methanesulfonate 3 3 3 Binder 75 tetrahexylammonium 90 15 51 65 resin 2 tetrafluoroborate 4 4 4 Binder 87 tetrahexylammonium 90 3 52 57 resin 3 tetrafluoroborate 5 5 5 Binder 88 1-ethyl-3- 62 2 53 57 resin 1 methylimidazolium hexafluorophosphate 6 6 6 Binder 88 1-benzyl-3- 136 2 53 57 resin 1 methylimidazolium hexafluorophosphate 7 7 7 Binder 70 1-butyl-4-methylpyridinium 158 20 45 55 resin 1 chloride 8 8 8 Binder 70 1-butyl-4-methylpyridinium 158 20 40 55 resin 1 hexafluorophosphate

(65) TABLE-US-00010 TABLE 3 Low- Example Comprehensive temperature Ejected paper Storage No. evaluation fixability adhesion stability 1 A A A A 2 A A A A 3 B B A A 4 B B B A 5 C C B A 6 C C B A 7 C A C B 8 C A C C

(66) In Table 3, the comprehensive evaluation means a level good for ranks of the low-temperature fixability and the ejected paper adhesion, and indicates the rank of compatibility between the low-temperature fixability and the ejected paper adhesion.

(67) [Comparative Examples 1 to 4]

(68) (Production Examples of Toners 9 to 12)

(69) Toners 9 to 12 were obtained in the same manner as in the Production Example of the toner 1, except that the types and amounts of the binder resins and the plasticizers were changed as shown in Table 4.

(70) (Production Examples of Two-Component Developers 9 to 12)

(71) Two-component developers 9 to 12 were obtained in the same manner as in the Production Example of the two-component developer 1, except that the toners were changed as shown in Table 4. Furthermore, the two-component developers 9 to 12 were evaluated in the same manner as the two-component developer 1. The evaluation results are shown in Table 5.

(72) TABLE-US-00011 TABLE 4 Binder resin Plasticizer Binder Number Melting Number Comparative Developer Toner resin of point of Tg1 Tg2 Example No. No. No. No. copies Name (° C.) copies (° C.) (° C.) 1 9 9 Binder 81 Hydrocarbon WAX 70 5 55 55 resin 4 2 10 10 Binder 81 — — — 55 55 resin 4 3 11 11 Binder 75 Crystalline polyester 1 75 5 45 42 resin 4 4 12 12 Binder 87 1,2,3- 113  7 55 55 resin 5 trimethylimidazolium methylsulfate

(73) TABLE-US-00012 TABLE 5 Low- Comparative Comprehensive temperature Ejected paper Storage Example No. evaluation fixability adhesion stability 1 D D C A 2 D D C A 3 D A D B 4 D D C A

(74) While the present disclosure 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.

(75) This application claims the benefit of Japanese Patent Application No. 2018-232102, filed Dec. 12, 2018, which is hereby incorporated by reference herein in its entirety.