Toner, toner cartridge, image forming apparatus

Abstract

The present application provides toner, toner cartridge containing the toner, and image forming apparatus, the toner has excellent low temperature fixing property, storage property, heat resistance, and can sufficiently maintain the charge amount even under high temperature and high humidity. The toner of the embodiment has toner parent particles and an external additive. The external additive has silica particles with a diameter of 70 to 120 nm. The silica particles have a degree of association of 80% or more. The toner parent particles contain a crystalline polyester resin and an ester wax. The ester wax is a polycondensate of three or more carboxylic acids and two or more alcohols. The proportion of the carboxylic acid with the largest content is 70 to 95% by mass. The proportion of the carboxylic acid with a carbon atom number of 18 or less is 5% by mass or less. The proportion of the alcohol with the largest content is 70 to 90% by mass. The proportion of the alcohol with a carbon atom number of 18 or less is 20% by mass or less. Degree of association (%) = (n2 / (n1+n2)) x 100. 50 The present application provides toner, toner cartridge containing the toner, and image forming apparatus, the toner has excellent low temperature fixing property, storage property, heat resistance, and can sufficiently maintain the charge amount even under high temperature and high humidity. The toner of the embodiment has toner parent particles and an external additive. The external additive has silica particles with a diameter of 70 to 120 nm. The silica particles have a degree of association of 80% or more. The toner parent particles contain a crystalline polyester resin and an ester wax. The ester wax is a polycondensate of three or more carboxylic acids and two or more alcohols. The proportion of the carboxylic acid with the largest content is 70 to 95% by mass. The proportion of the carboxylic acid with a carbon atom number of 18 or less is 5% by mass or less. The proportion of the alcohol with the largest content is 70 to 90% by mass. The proportion of the alcohol with a carbon atom number of 18 or less is 20% by mass or less. Degree of association (%) = (n2 / (n1+n2)) x 100.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to a toner, a toner cartridge, and an image forming apparatus. BACKGROUND

[0002] A toner containing a crystalline polyester resin is known (for example, Patent Literature 1). The low-temperature fixing property of the toner containing the crystalline polyester resin is excellent. However, the heat resistance and storage property of the toner containing the crystalline polyester resin are insufficient. Therefore, the toner containing the crystalline polyester resin is likely to form a soft block at a high temperature. The toner after the soft block is likely to solidify in an image forming apparatus to cause a blockage, thereby causing an image defect. Therefore, for the toner containing the crystalline polyester resin, it is required to improve the heat resistance and storage property.

[0003] On the other hand, it is effective to use an ester wax having excellent heat resistance for improving the heat resistance and storage property of the toner. However, if the ester wax and the crystalline polyester resin are used in combination, the dispersibility of the components in the toner is likely to decrease. As a result, it is difficult to control the charge amount of the toner. Further, it is more difficult to maintain the charge amount of the toner at a high temperature and high humidity such as in an image forming apparatus, and the flying amount of the toner is likely to decrease. The toner after the decrease in the flying amount is likely to deposit in the apparatus, thereby causing contamination.

[0004] In this way, in the toner containing the crystalline polyester, it is difficult to achieve both the excellent low-temperature fixing property and the maintenance of the charge amount. SUMMARY

[0005] The present application has an object to provide a toner, a toner cartridge containing the toner, and an image forming apparatus, the toner having excellent low-temperature fixing property, storage property, and heat resistance, and being capable of sufficiently maintaining a charge amount even at a high temperature and high humidity.

[0006] The toner of the embodiment has toner parent particles and an external additive. The external additive is attached to the surface of the toner parent particles. The toner parent particles contain a crystalline polyester resin and an ester wax.

[0007] The ester wax is a polycondensate of a first monomer group and a second monomer group. The first monomer group contains at least three or more kinds of carboxylic acids. The second monomer group contains at least two or more kinds of alcohols.

[0008] The proportion of the carboxylic acid having a carbon atom number of C n is 70 to 95 mass% with respect to 100 mass% of the first monomer group. The carbon atom number C n is the carbon atom number of the carboxylic acid having the largest content in the first monomer group. The proportion of the carboxylic acid having a carbon atom number of 18 or less in the first monomer group is 5 mass% or less with respect to 100 mass% of the first monomer group.

[0009] The proportion of the carboxylic acid having a carbon atom number of Cm The proportion of the alcohol having the carbon atom number Cmax in the second monomer group is 70 to 90 mass% with respect to 100 mass% of the second monomer group. The carbon atom number Cmax is the maximum content of the alcohol in the second monomer group. m m The proportion of the alcohol having the carbon atom number Cmax in the second monomer group is 70 to 90 mass% with respect to 100 mass% of the second monomer group. The carbon atom number Cmax is the maximum content of the alcohol in the second monomer group.

[0010] The external additive contains silica particles having a volume average primary particle diameter D 50 of 70 to 120 nm. The silica particles include primary particles and secondary particles of silica. The secondary particles are aggregates of two or more primary particles of silica. The silica particles have a degree of aggregation of 80% or more calculated from the following formula.

[0011] Degree of aggregation (%) = (n2 / (n1+n2)) x 100

[0012] In the formula, n1 is the number of primary particles measured for one toner parent particle, and n2 is the number of secondary particles measured for one toner parent particle. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a drawing showing an example of a schematic structure of an image forming apparatus of the embodiment.

[0014] Figure 2 is a drawing showing results measured in the embodiment for the relationship between the degree of aggregation of the silica particles and the adhesion strength of the external additive.

[0015] SYMBOL EXPLANATION

[0016] 1a, 1b: photosensitive drum; 2a, 2b: charging device; 3a, 3b: exposure device; 4a: first developer; 4b: second developer; 7: intermediate transfer belt; 8a, 8b: primary transfer roller; 9: secondary transfer roller; 10: backup roller; 11: heating roller; 12: pressure roller; 14a: primary transfer power source; 14b: primary transfer power source; 15: secondary transfer power source; 16a: cleaning device; 16b: cleaning device; 17A: first image forming unit; 17B: second image forming unit; 20: image forming apparatus; 21: fixing device DETAILED DESCRIPTION

[0017] Hereinafter, the toner of the embodiment will be described.

[0018] The toner of the embodiment has a toner parent particle and an external additive.

[0019] The toner parent particle will be described.

[0020] The toner parent particle of the embodiment contains the crystalline polyester resin and the ester wax. The toner parent particle of the embodiment can contain, in addition to the crystalline polyester resin, the ester wax, other binder resins other than the crystalline polyester resin, and colorants. The toner parent particle of the embodiment can further contain other components other than the crystalline polyester resin, the ester wax, the other binder resins, and the colorants, if it is within a range in which the effects disclosed in the embodiment can be obtained.

[0021] The crystalline polyester resin is described.

[0022] The crystalline polyester resin is used as a binder resin. Since the toner parent particle contains the crystalline polyester resin, the low-temperature fixing property of the toner of the embodiment is excellent.

[0023] In the embodiment, a polyester resin having a ratio of softening temperature to melting temperature (softening temperature / melting temperature) of 0.8 to 1.2 is used as the "crystalline polyester resin". In addition, a polyester resin having a ratio of softening temperature to melting temperature (softening temperature / melting temperature) of less than 0.8 or more than 1.2 is used as the "non-crystalline polyester resin".

[0024] As the crystalline polyester resin, for example, a polycondensate of a dihydric or more alcohol and a dihydric or more carboxylic acid can be exemplified.

[0025] As the dihydric or more alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-butanediol, polyoxypropylene, polyoxyethylene, glycerol, pentaerythritol, trimethylolpropane, or the like can be exemplified. As the dihydric or more alcohol, 1,4-butanediol, 1,6-hexanediol is preferable.

[0026] As the dihydric or more carboxylic acid, adipic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaric acid, succinic acid, phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, azelaic acid, alkyl- or alkenyl-substituted succinic acid, cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, anhydrides thereof, or esters thereof, or the like can be exemplified.

[0027] As the alkyl- or alkenyl-substituted succinic acid, succinic acid substituted with an alkyl group or an alkenyl group having 2 to 20 carbon atoms can be exemplified. For example, n-dodecenyl succinic acid, n-dodecyl succinic acid, or the like can be exemplified. As the dihydric or more carboxylic acid, fumaric acid is preferable.

[0028] However, the crystalline polyester resin is not limited to the polycondensate of the dihydric or more alcohol and the dihydric or more carboxylic acid exemplified herein. The crystalline polyester resin can be used alone as any one of them or two or more of them can be used in combination.

[0029] The weight average molecular weight of the crystalline polyester resin is preferably 6 x 10 3 ~ 18 x 10 3 , more preferably 8 x 10 3 ~ 14 x 10 3 . If the weight average molecular weight of the crystalline polyester resin is equal to or greater than the lower limit value, the low temperature fixing property of the toner is more excellent. In addition, if the weight average molecular weight of the crystalline polyester resin is equal to or less than the upper limit value, the storage property of the toner is more preferable, and the low temperature offset resistance is also excellent.

[0030] In the present specification, the weight average molecular weight is a value converted to polystyrene obtained by gel permeation chromatography.

[0031] The melting point of the crystalline polyester resin is preferably 60 to 120°C, more preferably 70 to 115°C, and further preferably 80 to 110°C. If the melting point of the crystalline polyester resin is equal to or greater than the lower limit value, the storage property and heat resistance of the toner are more excellent. If the melting point of the crystalline polyester resin is equal to or less than the upper limit value, the low temperature fixing property of the toner is more excellent.

[0032] The melting point of the crystalline polyester resin can be measured by, for example, a differential scanning calorimeter (DSC).

[0033] The other binder resin will be described.

[0034] As the other binder resin, for example, a non-crystalline polyester resin, a styrene-based resin, an ethylene-based resin, an acrylic resin, a phenol-based resin, an epoxy-based resin, an allyl phthalate-based resin, a polyamide-based resin, a maleic acid-based resin, and the like can be exemplified. However, the other binder resin is not limited to these examples.

[0035] The other binder resin can be used alone as any one kind, or two or more kinds can be used in combination.

[0036] From the aspect of easily obtaining the effects disclosed in the embodiments, the other binder resin is preferably a non-crystalline polyester resin. As the non-crystalline polyester resin, for example, a polycondensate of a dihydric or more carboxylic acid and a dihydric alcohol can be exemplified.

[0037] As the dihydric or more carboxylic acid, a dihydric or more carboxylic acid, an anhydride of a dihydric or more carboxylic acid, an ester of a dihydric or more carboxylic acid, and the like can be exemplified. As the ester of a dihydric or more carboxylic acid, a lower alkyl (carbon number: 1 to 12) ester of a dihydric or more carboxylic acid can be exemplified.

[0038] As the dihydric alcohol, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-butylenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, bisphenol A, hydrogenated bisphenol A, alkylene oxide adduct of bisphenol A, and the like can be exemplified. However, the dihydric alcohol is not limited to these examples.

[0039] As the alkylene oxide adduct of bisphenol A, a compound obtained by adding an alkylene oxide having 2 to 3 carbon atoms in an average of 1 to 10 moles to bisphenol A can be exemplified. As the alkylene oxide adduct of bisphenol A, polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (2.0)-polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (6)-2,2-bis(4-hydroxyphenyl)propane, and the like can be exemplified.

[0040] As the dihydric alcohol, the alkylene oxide adduct of bisphenol A is preferable. The dihydric alcohol can be used alone as any one of them or two or more of them in combination.

[0041] The other binder resin is obtained by, for example, polymerizing a vinyl polymerizable monomer alone or a plurality of them.

[0042] As the vinyl polymerizable monomer, for example, an aromatic vinyl monomer, an ester monomer, a carboxylic acid-containing monomer, an amine monomer can be exemplified.

[0043] As the aromatic vinyl monomer, for example, styrene, methylstyrene, methoxystyrene, phenylstyrene, chlorostyrene, derivatives thereof, and the like can be exemplified.

[0044] As the ester monomer, for example, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, derivatives thereof can be exemplified.

[0045] As the carboxylic acid-containing monomer, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid, derivatives thereof can be exemplified.

[0046] As the amine monomer, for example, amino acrylate, acrylamide, methacrylamide, vinylpyridine, vinylpyrrolidone, derivatives thereof can be exemplified.

[0047] The other binder resin can be obtained by polycondensation of a polymerizable monomer component including an alcohol component and a carboxylic acid component. At the time of polycondensation of the polymerizable monomer component, various aids such as a chain transfer agent, a crosslinking agent, a polymerization initiator, a surfactant, a coagulant, a pH adjuster, an antifoaming agent, and the like can be used.

[0048] An ester wax is described.

[0049] The ester wax of the embodiment contains two or more ester compounds different in the number of carbon atoms. Since the toner parent particles contain the ester wax, the toner is excellent in heat resistance and storability.

[0050] The ester wax of the embodiment is a polycondensate of a first monomer group and a second monomer group.

[0051] The first monomer group is described.

[0052] The first monomer group contains at least three or more carboxylic acids. From the viewpoint of easy availability of the ester wax, the number of kinds of the carboxylic acids of the first monomer group is preferably seven or less, more preferably five or less, and further preferably four or less.

[0053] Here, the number of carbon atoms of the carboxylic acid having the largest content in the first monomer group is denoted as C n . The number of carbon atoms C n is preferably 19 to 28, more preferably 19 to 24, and further preferably 20 to 24. If the number of carbon atoms C n is the lower limit value or more, the heat resistance of the ester wax is improved. If the number of carbon atoms C n is the upper limit value or less, the low-temperature fixing property of the toner is more excellent.

[0054] The proportion of the carboxylic acid having the largest content and the number of carbon atoms C n is 70 to 95% by mass, preferably 80 to 95% by mass, and more preferably 85 to 95% by mass, with respect to 100% by mass of the first monomer group. If the proportion of the carboxylic acid having the number of carbon atoms C n is the lower limit value or more, the extreme peak of the carbon atom number distribution of the ester wax is sufficiently easily located on the high carbon atom number side. If the proportion of the carboxylic acid having the number of carbon atoms C n is the upper limit value or less, the ester wax is easily obtained.

[0055] The proportion of the carboxylic acid having the number of carbon atoms of 18 or less in the first monomer group is 5% by mass or less, preferably 0 to 5% by mass, and more preferably 0 to 1% by mass, with respect to 100% by mass of the first monomer group. If the proportion of the carboxylic acid having the number of carbon atoms of 18 or less is the lower limit value or more, the ester wax is easily obtained. If the proportion of the carboxylic acid having the number of carbon atoms of 18 or less is the upper limit value or less, the proportion of the ester compound having a relatively low molecular weight in the ester wax is reduced. As a result, the toner is excellent in storability and heat resistance.

[0056] The content of each carbon number carboxylic acid in the first monomer group can be determined by, for example, quantitatively analyzing the product after a methanolysis reaction on the ester wax using FD-MS (Field Desorption Mass Spectrometry). The total of the ion intensity of each carbon number carboxylic acid in the product measured by FD-MS is taken as 100. The relative value of the ion intensity of each carbon number carboxylic acid to the total is calculated. This relative value is taken as the content of each carbon number carboxylic acid in the first monomer group. In addition, the carbon number of the carboxylic acid having the largest relative value is taken as C n .

[0057] As the carboxylic acid in the first monomer group, from the aspect of easy availability of the ester wax, a long chain carboxylic acid, preferably a long chain alkyl carboxylic acid is preferred. The long chain carboxylic acid is appropriately selected so that the ester wax satisfies the prescribed requirements.

[0058] As the long chain carboxylic acid, a long chain carboxylic acid having a carbon number of 19 to 28 is preferred, and a long chain carboxylic acid having a carbon number of 20 to 24 is more preferred. If the carbon number of the long chain carboxylic acid is the lower limit value or more, the heat resistance of the ester wax is improved, and the storage property and heat resistance of the toner are more excellent. If the carbon number of the long chain carboxylic acid is the upper limit value or less, the low temperature fixing property of the toner is more excellent. As the long chain alkyl carboxylic acid, for example, palmitic acid, stearic acid, arachidonic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, and the like can be exemplified.

[0059] The second monomer group is described.

[0060] The second monomer group contains at least two or more alcohols. From the aspect of easy availability of the ester wax, the number of types of alcohols in the second monomer group is preferably five or less, more preferably four or less, and further preferably three or less.

[0061] Here, the carbon number of the alcohol having the largest content in the second monomer group is taken as C m . The carbon number C m is preferably 19 to 28, more preferably 20 to 24, and further preferably 20 to 22. If the carbon number C m is the lower limit value or more, the heat resistance of the ester wax is improved. If the carbon number C m is the upper limit value or less, the low temperature fixing property of the toner is more excellent.

[0062] The proportion of the alcohol having the largest content and having a carbon number of C m is 70 to 90 mass% with respect to 100 mass% of the second monomer group, preferably 80 to 90 mass%, and more preferably 85 to 90 mass%. If the carbon number is C mthe lower limit value, the maximum peak of the carbon number distribution of the ester wax is sufficiently easily positioned on the high carbon number side. If the proportion of the alcohol having a carbon number of C m or less is below the upper limit value, the ester wax is easily obtained.

[0063] The proportion of the alcohol having a carbon number of 18 or less in the second monomer group is 20% by mass or less, preferably 10 to 20% by mass, and more preferably 15 to 20% by mass, relative to 100% by mass of the second monomer group. If the proportion of the alcohol having a carbon number of 18 or less is the lower limit value or more, the ester wax is easily obtained. If the proportion of the alcohol having a carbon number of 18 or less is the upper limit value or less, the proportion of the ester compound having a relatively low molecular weight in the ester wax is reduced. As a result, the storage property and heat resistance of the toner are excellent.

[0064] The content of the alcohol having each carbon number in the second monomer group can be determined by, for example, performing mass analysis on the product after the methanolysis reaction of the ester wax using FD-MS. The total of the ion intensity of the alcohol having each carbon number in the product measured using FD-MS is set to 100. The relative value of the ion intensity of the alcohol having each carbon number relative to the total is calculated. This relative value is taken as the content of the alcohol having each carbon number in the second monomer group. In addition, the carbon number of the alcohol having the largest relative value is taken as C m .

[0065] As the alcohol in the second monomer group, a long-chain alcohol, and more preferably a long-chain alkyl alcohol, is preferable from the aspect of easily obtaining the ester wax. The long-chain alcohol is appropriately selected so that the ester wax satisfies the prescribed requirements. As the long-chain alcohol, a long-chain alcohol having a carbon number of 19 to 28 is preferable, and a long-chain alcohol having a carbon number of 20 to 22 is more preferable. If the carbon number of the long-chain alcohol is the lower limit value or more, the heat resistance of the ester wax is improved, and the storage property and heat resistance of the toner are more excellent. If the carbon number of the long-chain alcohol is the upper limit value or less, the low-temperature fixing property of the toner is more excellent.

[0066] As the long-chain alkyl alcohol, for example, the following can be listed: palmitol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, ceryl alcohol, montanyl alcohol.

[0067] In the ester wax of the embodiment, it is preferable that the ester compound having the largest content in the ester compound constituting the ester wax of the embodiment have a carbon number of C l or more. The carbon number C l is preferably 43 or more, more preferably 43 to 56, further preferably 43 to 52, particularly preferably 44 to 46, and most preferably 44. If the carbon number C l is the lower limit value or more, the maximum peak of the carbon number distribution of the ester wax is sufficiently easily positioned on the high carbon number side. As a result, the storage property and heat resistance of the toner are more excellent. If the carbon number C lThe upper limit value is preferably 42 or more, more preferably 42 to 55, further preferably 42 to 51, particularly preferably 43 to 45, most preferably 43.

[0068] The ester compound having a carbon number of C l is represented by the following formula (I).

[0069] R 1 COOR 2 (I)

[0070] R 1 in formula (I) is an alkyl group. R 2 in formula (I) is an alkyl group. The total of the carbon numbers of R 1 and R 2 is preferably 42 or more, more preferably 42 to 55, further preferably 42 to 51, particularly preferably 43 to 45, most preferably 43. 1 The total of the carbon numbers of R 2 and R 1 is preferably 42 or more, more preferably 42 to 55, further preferably 42 to 51, particularly preferably 43 to 45, most preferably 43. 2 The total of the carbon numbers of R 1 and R n can be controlled by adjusting the carbon number C n of the carboxylic acid having a carbon number of C 2 described later. The total of the carbon numbers of R m and R m can be controlled by adjusting the carbon number C l of the alcohol having a carbon number of C l described later.

[0071] The proportion of the ester compound having a carbon number of C l is preferably 65% by mass or more, more preferably 65 to 90% by mass, further preferably 70 to 90% by mass, particularly preferably 80 to 90% by mass, with respect to 100% by mass of the ester wax. If the proportion of the ester compound having a carbon number of C l is the lower limit value or more, the maximum peak of the carbon number distribution of the ester wax becomes sufficiently high. As a result, the storage property and heat resistance of the toner are more excellent.

[0072] If the proportion of the ester compound having a carbon number of C l is the upper limit value or less, the ester wax is easily obtained.

[0073] The carbon number distribution of the ester wax of the embodiment preferably has only one maximum peak in the region of a carbon number of 43 or more. In this case, the proportion of the ester compound having a relatively low molecular weight becomes small. As a result, the storage property and heat resistance of the toner are more excellent.

[0074] In the carbon number distribution of the ester wax of the embodiment, the position of the maximum peak is preferably in the range of carbon number 43 to 56, more preferably in the range of carbon number 44 to 52, further preferably in the range of carbon number 44 to 46, and most preferably in the range of carbon number 44. If the position of the maximum peak is in the range of carbon number above the lower limit value, the storage property and heat resistance of the toner are more excellent. If the position of the maximum peak is in the range of carbon number below the upper limit value, the ester wax is easily obtained.

[0075] The content of the ester compound of each carbon number in the ester wax can be determined by, for example, mass analysis using FD-MS. The total of the ion intensity of the ester compound of each carbon number in the ester wax measured by FD-MS is taken as 100. The relative value of the ion intensity of the ester compound of each carbon number to the total is calculated. The relative value is taken as the content of the ester compound of each carbon number in the ester wax. In addition, the carbon number of the ester compound of the carbon number at which the relative value is the largest is taken as C l .

[0076] The method for producing the ester wax is described.

[0077] The ester wax can be produced by, for example, esterification reaction of a long-chain carboxylic acid and a long-chain alcohol. In the esterification reaction, at least three or more kinds of long-chain alkyl carboxylic acids and at least two or more kinds of long-chain alkyl alcohols are preferably used from the viewpoint of easily obtaining an ester wax satisfying the prescribed requirements. If the use amount of each of the at least three kinds of long-chain alkyl carboxylic acids and the at least two kinds of long-chain alkyl alcohols is adjusted, the carbon number distribution of the ester compound contained in the ester wax can be adjusted. The esterification reaction is preferably performed while heating under a stream of nitrogen.

[0078] The esterification reactant can be purified by dissolving the esterification reactant in a solvent such as methanol, toluene, and the like, and then adding an alkaline aqueous solution such as an aqueous sodium hydroxide solution, and separating an organic layer and an aqueous layer. The aqueous layer is removed, and thus the ester wax can be obtained. The purification operation is preferably performed repeatedly a plurality of times.

[0079] The colorant is described.

[0080] The colorant is not particularly limited. Examples include pigments such as carbon black, cyan, yellow, magenta, and the like, dyes, and the like.

[0081] As the carbon black, examples include aniline black, lamp black, acetylene black, furnace black, thermal black, channel black, and the like.

[0082] As pigments, dyes, for example, Fast Yellow G, benzidine yellow, chrome yellow, quinoline yellow, Indofast Orange, Irgazin Red, Carmine FB, Permanent Red FRR, Pigment Orange R, Lithol Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, DuPont Oil Red, phthalocyanine blue, pigment blue, aniline blue, Calcoil Blue, ultramarine blue, Brilliant Green B, phthalocyanine green, malachite green oxalate, methylene blue chloride, Rose Bengal, quinacridone, and the like can be listed.

[0083] As colorants, for example, C.I. Pigment Black 1, 6, 7, C.I. Pigment Yellow 1, 12, 14, 17, 34, 74, 83, 97, 155, 180, 185, C.I. Pigment Orange 48, 49, C.I. Pigment Red 5, 12, 31, 48, 48: 1, 48:2, 48:3, 48:4, 48:5, 49, 53, 53: 1, 53:2, 53:3, 57, 57: 1, 81, 81:4, 122, 146, 150, 177, 185, 202, 206, 207, 209, 238, 269, C.I. Pigment Blue 15, 15: 1, 15:2, 15:3, 15:4, 15:5, 15:6, 75, 76, 79, C.I. Pigment Green 1, 7, 8, 36, 42, 58, C.I. Pigment Violet 1, 19, 42, C.I. Acid Red 52, and the like can be listed according to the designations in the Color Index. However, the colorants are not limited to these examples.

[0084] The colorants can be used alone as any one of them or in combination of two or more of them.

[0085] The other ingredients will be described.

[0086] As the other ingredients, additives such as a charge control agent, a surfactant, an alkaline compound, a coagulant, a pH adjuster, an antioxidant, and the like can be listed. However, the additives are not limited to these examples. The additives can be used alone as any one of them or in combination of two or more of them.

[0087] The charge control agent will be described.

[0088] In the case where the toner parent particles contain a charge control agent, the toner is easily transferred to a recording medium such as paper. As the charge control agent, a metal-containing azo compound, a metal-containing salicylic acid derivative compound, a metal oxide hydrophobized product, a clathrate compound of a polysaccharide, or the like can be exemplified. As the metal-containing azo compound, a complex or a complex salt in which the metal is iron, cobalt, or chromium, or a mixture thereof is preferable. As the metal-containing salicylic acid derivative compound, a metal oxide hydrophobized product, a complex or a complex salt in which the metal is zirconium, zinc, chromium, or boron, or a mixture thereof is preferable. As the clathrate compound of a polysaccharide, a clathrate compound of a polysaccharide containing aluminum (Al) and magnesium (Mg) is preferable.

[0089] The composition of the toner parent particles will be described.

[0090] The content of the crystalline polyester resin is preferably 5 to 25 mass%, more preferably 5 to 20 mass%, and further preferably 5 to 15 mass% with respect to 100 mass% of the toner parent particles. If the content of the crystalline polyester resin is equal to or greater than the lower limit value, the low-temperature fixing property of the toner is more excellent. In addition, if the content of the crystalline polyester resin is equal to or less than the upper limit value, the low-temperature offset resistance and the high-temperature offset resistance of the toner are more excellent.

[0091] The content of the ester wax is preferably 3 to 15 mass%, more preferably 3 to 13 mass%, and further preferably 5 to 10 mass% with respect to 100 mass% of the toner parent particles. If the content of the ester wax is equal to or greater than the lower limit value, the storability and the heat resistance of the toner are more excellent. In addition, if the content of the ester wax is equal to or less than the upper limit value, the low-temperature fixing property of the toner is more excellent, and the charge amount is easily sufficiently maintained.

[0092] In the case where the toner parent particles contain a non-crystalline polyester resin, the content of the non-crystalline polyester resin is preferably 60 to 90 mass%, more preferably 65 to 85 mass%, and further preferably 70 to 80 mass% with respect to 100 mass% of the toner parent particles. If the content of the non-crystalline polyester resin is equal to or greater than the lower limit value, the offset resistance of the toner is more excellent. In addition, if the content of the non-crystalline polyester resin is equal to or less than the upper limit value, the low-temperature fixing property of the toner is more excellent.

[0093] In the case where the toner parent particles contain a colorant, the content of the colorant is preferably 2 to 13 mass%, and more preferably 3 to 8 mass% with respect to 100 mass% of the toner parent particles. If the content of the colorant is equal to or greater than the lower limit value, the color reproducibility of the toner is excellent. In addition, if the content of the colorant is equal to or less than the upper limit value, the dispersibility of the colorant is excellent, and the low-temperature fixing property of the toner is more excellent. In addition, the charge amount of the toner is easily controlled.

[0094] The external additive will be described.

[0095] The external agent contains specific silica particles α. The silica particles α have a volume average primary particle diameter D 50 is 70 to 120 nm, and the degree of aggregation is 80% or more. The silica particles α contain primary particles of silica and secondary particles. The primary particles of silica mean one particle of silica. The primary particles of silica are preferably spherical, and more preferably true spherical.

[0096] The secondary particles are aggregates of two or more primary particles of silica. Therefore, the secondary particles form a random shape. The specific shape of the secondary particles is not particularly limited. The secondary particles can be in a polyhedral shape, a polygonal prism shape, or an ellipsoidal shape.

[0097] The aspect ratio of the secondary particles can be made 0.92 or less. The aspect ratio of the secondary particles refers to the ratio of the short diameter to the long diameter.

[0098] As the silica particles α, from the viewpoint of further improving the heat resistance of the toner, hydrophobic silica particles are preferred. The hydrophobic silica particles are, for example, obtained by hydrophobically treating the surface silanol groups of the wet-process silica described later with silane, silicone, or the like. If the hydrophobic silica particles are used as the external agent of the toner, the adhesion to the toner base particles becomes good.

[0099] The degree of hydrophobization of the hydrophobic silica can be measured by, for example, the following method. Ion-exchanged water 50 ml and a sample 0.2 g are put in a beaker, and methanol is added from a burette while stirring with an electromagnetic stirrer. Then, the powder gradually settles as the concentration of methanol in the beaker increases, and the volume % of methanol in the mixed solution of methanol and ion-exchanged water at the end point when the total amount has settled is taken as the degree of hydrophobization (%).

[0100] The degree of aggregation of the silica particles α is 80% or more, preferably 80 to 95%, and more preferably 80 to 90%. Since the degree of aggregation of the silica particles α is the lower limit value or more, the proportion of amorphous silica in the external agent is high. Therefore, the silica particles α are not easily peeled off from the surface of the toner base particles. In this way, the adhesion strength of the external agent to the toner base particles is enhanced, and therefore, the external agent is not easily peeled off even if the toner is stirred in the developing device under high temperature and high humidity. As a result, the toner can sufficiently maintain the charge amount even under high temperature and high humidity. If the degree of aggregation of the silica particles α is the upper limit value or less, the external agent is easily and uniformly attached to the surface of the toner base particles. Therefore, the charge amount distribution shows a sharp shape, and the charge amount is easily controlled.

[0101] The degree of aggregation of the silica particles α is calculated from the following formula.

[0102] Degree of aggregation (%) = (n2 / (n1 + n2)) x 100

[0103] In the formula, n1 is the number of primary particles measured for one toner parent particle, and n2 is the number of secondary particles measured for one toner parent particle.

[0104] n1 and n2 can be measured by observation of, for example, electron micrographs, image analysis.

[0105] The volume average primary particle diameter D of the silica particles α 50 is 70 to 120 nm, preferably 75 to 115 nm, and more preferably 80 to 110 nm. If the volume average primary particle diameter D of the silica particles α 50 is greater than the lower limit value, the charge amount of the toner of the embodiment increases, and the flying amount of the toner is sufficiently maintained. If the volume average primary particle diameter D of the silica particles α 50 is less than the upper limit value, the toner of the embodiment is not easily overcharged, and the flying amount of the toner is not easily made excessively large. As a result, the damage to the photoreceptor in the image forming apparatus is reduced.

[0106] As the silica particles α, from the aspect of more sufficiently maintaining the charge amount of the toner, a wet-process silica is preferred. The wet-process silica can be produced by, for example, a method (liquid phase method) in which sodium silicate using silica sand as a raw material is used as a raw material, an aqueous solution containing the sodium silicate is neutralized to precipitate silica, and the precipitate is filtered and dried. In contrast, sintered silica (dry-process silica) obtained by reacting silicon tetrachloride in a high-temperature flame is known. If the wet-process silica is used as an external additive for the toner, the charge amount of the toner is generally more easily maintained than in the case of sintered silica having a low water content.

[0107] The external additive preferably further contains either or both of strontium titanate and titanium oxide in addition to the silica particles α. If the external additive further contains either or both of strontium titanate and titanium oxide, the charge amount of the toner is not easily made excessively high. In addition, the charge amount distribution of the toner easily exhibits a sharp shape. As a result, the flying amount of the toner is not easily made excessively large, and the damage to the photoreceptor in the image forming apparatus is reduced. In addition, the charge amount of the toner is appropriately maintained even under low temperature and low humidity.

[0108] The external additive can further contain other inorganic oxides in addition to the silica particles, strontium titanate, and titanium oxide. As the other inorganic oxides, for example, alumina, tin oxide, and the like can be listed.

[0109] From the aspect of improved stability, the particles containing the silica particles and the inorganic oxides can be surface-treated with a hydrophobic agent. The inorganic oxides can be used alone as any one kind, or two or more kinds can be used in combination.

[0110] The content of the external additive is preferably 2 to 15 parts by mass, more preferably 4 to 10 parts by mass, and further preferably 4 to 8 parts by mass, relative to 100 parts by mass of the toner base particles 100. If the content of the external additive is equal to or greater than the lower limit value, the charge amount of the toner can be easily ensured. Thus, the charge amount can be further sufficiently maintained even under high temperature and high humidity. If the content of the external additive is equal to or less than the upper limit value, the charge amount of the toner is not easily made excessively high. Thus, the charge amount of the toner can be easily moderately maintained.

[0111] A method for producing the toner will be described.

[0112] The toner of the embodiment can be produced by mixing the toner base particles and the external additive. By mixing the toner base particles and the external additive, the external additive is attached to the surface of the toner base particles.

[0113] The toner base particles of the embodiment can be produced by, for example, a kneading and pulverizing method, a chemical method.

[0114] The kneading and pulverizing method will be described.

[0115] As the kneading and pulverizing method, for example, a production method including a mixing step, a kneading step, and a pulverizing step of the following can be exemplified. The kneading and pulverizing method can further include a classifying step of the following as needed.

[0116] • The mixing step: a step of mixing at least the crystalline polyester resin and the ester wax to obtain a mixture.

[0117] • The kneading step: a step of melt-kneading the mixture to obtain a kneaded product.

[0118] • The pulverizing step: a step of pulverizing the kneaded product to obtain a pulverized product.

[0119] • The classifying step: a step of classifying the pulverized product.

[0120] In the mixing step, the raw materials of the toner are mixed to obtain a mixture. A mixer can also be used in the mixing step. The mixer is not particularly limited. In the mixing step, a colorant, another binder resin, an additive can be used as needed.

[0121] In the kneading step, the mixture obtained in the mixing step is melt-kneaded to obtain a kneaded product. A kneader can be used in the kneading step. The kneader is not particularly limited.

[0122] In the pulverization step, the kneaded material obtained in the kneading step is pulverized to obtain a pulverized material. In the pulverization step, a pulverizer can be used. As the pulverizer, various kinds of pulverizers such as a hammer mill can be used. In addition, the pulverized material obtained by the pulverizer can be further micronized. As the pulverizer for further micronizing the pulverized material, various kinds of pulverizers can be used. The pulverized material obtained in the pulverization step can be directly used as the toner parent particles, or can be made into the toner parent particles after passing through the classification step as needed.

[0123] In the classification step, the pulverized material obtained in the pulverization step is classified. In the classification step, a classifier can be used. The classifier is not particularly limited.

[0124] The chemical method will be described.

[0125] In the chemical method, a crystalline polyester resin, an ester wax, other binder resins used as needed, and an additive are mixed to obtain a mixture. Next, the mixture is melt-kneaded to obtain a kneaded material. Next, the kneaded material is pulverized to obtain a coarser intermediate particle. Next, the intermediate particle is mixed with an aqueous medium to prepare a mixed liquid. Next, the mixed liquid is subjected to mechanical shearing to obtain a fine particle dispersion liquid. Finally, the fine particles are aggregated in the fine particle dispersion liquid to produce toner parent particles.

[0126] The method of adding the external additive will be described.

[0127] The external additive is mixed with the toner parent particles by, for example, a mixer. The mixer is not particularly limited.

[0128] The external additive can be sieved by a sieving device as needed. The sieving device is not particularly limited. Various kinds of sieving devices can be used.

[0129] The toner cartridge of the embodiment will be described.

[0130] The toner cartridge of the embodiment contains the toner of the above-described embodiment. For example, the toner cartridge has a container that contains the toner of the embodiment. The container is not particularly limited, and various kinds of containers that can be used for an image forming apparatus can be used.

[0131] The toner of the embodiment can be used as a single-component developer, or can be used as a two-component developer in combination with a carrier.

[0132] The image forming apparatus of the embodiment will be described below with reference to the drawings.

[0133] Figure 1 is a drawing showing an example of a schematic configuration of an image forming apparatus of the embodiment.

[0134] The image forming apparatus 20 of the embodiment has an apparatus main body that has the intermediate transfer belt 7, the first image forming unit 17A, the second image forming unit 17B, and the fixing device 21 that are disposed in this order on the intermediate transfer belt 7. The first image forming unit 17A is disposed downstream of the second image forming unit 17B in the advancing direction X of the intermediate transfer belt 7, that is, in the proceeding direction of the image forming process. The fixing device 21 is disposed downstream of the first image forming unit 17A.

[0135] The first image forming unit 17A has the photosensitive drum la, the cleaning device 16a, the charging device 2a, the exposure device 3a, the first developer 4a, and the primary transfer roller 8a. The cleaning device 16a, the charging device 2a, the exposure device 3a, and the first developer 4a are disposed in this order in the rotation direction of the photosensitive drum la. The primary transfer roller 8a is disposed opposite the photosensitive drum la via the intermediate transfer belt 7. The primary transfer roller 8a is connected to the primary transfer power source 14a.

[0136] The second image forming unit 17B has the photosensitive drum lb, the cleaning device 16b, the charging device 2b, the exposure device 3b, the second developer 4b, and the primary transfer roller 8b. The cleaning device 16b, the charging device 2b, the exposure device 3b, and the second developer 4b are disposed in this order in the rotation direction of the photosensitive drum lb. The primary transfer roller 8b is disposed opposite the photosensitive drum lb via the intermediate transfer belt 7. The primary transfer roller 8b is connected to the primary transfer power source 14b.

[0137] The toner of the above-described embodiment is housed in the first developer 4a and the second developer 4b. In the image forming apparatus of the other embodiment, the toner can be supplied from a toner cartridge that is not shown in the drawing.

[0138] The secondary transfer roller 9 and the backup roller 10 are disposed opposite each other via the intermediate transfer belt 7 downstream of the first image forming unit 17A. The secondary transfer roller 9 is connected to the secondary transfer power source 15.

[0139] The fixing device 21 is disposed downstream of the first image forming unit 17A. The fixing device 21 has the heating roller 11 and the pressure roller 12 that are disposed opposite each other. The fixing device 21 is a device for fixing toner to a recording medium. By heating and pressing with the heating roller 11 and the pressure roller 12, a toner image is fixed to paper.

[0140] An image is formed by the image forming apparatus 20, for example, as follows.

[0141] First, the photosensitive drum lb is uniformly charged by the charging device 2b. Next, exposure is performed by the exposure device 3b, and a latent electrostatic image is formed. Next, development is performed using the toner of the embodiment supplied from the developer 4b, and a second toner image is obtained.

[0142] Next, the photosensitive drum la is uniformly charged by the charging device 2a. Next, exposure is performed by the exposure device 3a based on the first image information (the second toner image), and a latent electrostatic image is formed. Next, development is performed using the toner of the embodiment supplied from the developer 4a, and a first toner image is obtained.

[0143] The second toner image, the first toner image are sequentially transferred on the intermediate transfer belt 7 using the primary transfer rollers 8a, 8b.

[0144] The image sequentially stacked on the intermediate transfer belt 7 in the order of the second toner image, the first toner image is secondary transferred on a recording medium not shown in the figure via the secondary transfer roller 9 and the backup roller 10. Thereby, an image sequentially stacked in the order of the first toner image, the second toner image is formed on the recording medium.

[0145] Figure 1 The image forming apparatus shown is of a form in which a toner image is fixed. However, the image forming apparatus of the embodiment is not limited to this form. The image forming apparatus of another embodiment can be of a form such as an inkjet form.

[0146] The low temperature fixability, the storability, the heat resistance of the toner of at least one embodiment described above are excellent, and the charge amount can be sufficiently maintained even under high temperature and high humidity.

[0147] Example

[0148] Hereinafter, an example will be shown to more specifically describe the embodiment.

[0149] The preparation of the ester waxes A to O of the example will be described.

[0150] A four-necked flask equipped with a stirrer, a thermocouple, and a nitrogen inlet tube was charged with at least three or more long-chain alkyl carboxylic acids 80 parts by mass and at least two or more long-chain alkyl alcohols 20 parts by mass. An esterification reaction was carried out at 220°C under a stream of nitrogen to obtain a reaction product. The obtained reaction product was added to a mixed solvent of toluene and methanol to dissolve the reaction product. An aqueous sodium hydroxide solution was further added to the flask, and the contents were stirred at 70°C for 30 minutes. The contents were allowed to stand for 30 minutes to separate the contents into an organic layer and an aqueous layer, and the aqueous layer was removed from the contents. Then, ion-exchanged water was added to the flask, and the contents were stirred at 70°C for 30 minutes. The contents were allowed to stand for 30 minutes to separate the contents into an aqueous layer and an organic layer, and the aqueous layer was removed from the contents. This operation was repeated five times. The solvent was distilled off from the organic layer of the contents in the flask under reduced pressure to obtain an ester wax A.

[0151] An ester wax B to O was obtained in the same manner as the ester wax A except that the kinds and amounts of the long-chain alkyl carboxylic acids and the long-chain alkyl alcohols used were changed.

[0152] The long-chain alkyl carboxylic acids used were as follows.

[0153]

[0154] The long-chain alkyl alcohols used were as follows.

[0155]

[0156] The crystalline polyester resins A to G used in each example were described.

[0157] The weight average molecular weights Mw and the melting points of the crystalline polyester resins A to G were as follows, respectively.

[0158] Crystalline polyester resin B (Mw: 8300, melting point: 70°C)

[0159] Crystalline polyester resin C (Mw: 8500, melting point: 80°C)

[0160] Crystalline polyester resin D (Mw: 9000, melting point: 85°C)

[0161] Crystalline polyester resin E (Mw: 9300, melting point: 90°C)

[0162] Crystalline polyester resin F (Mw: 9500, melting point: 100°C)

[0163] Crystalline polyester resin G (Mw: 13000, melting point: 110°C)

[0164] The non-crystalline polyester resin used in each example had a mass average molecular weight of 20,000 and a melting point of 110°C.

[0165] The volume average primary particle diameter Dv,10 of the hydrophobic strontium titanate, hydrophobic titanium oxide used in each example was 20 nm. 50 The volume average primary particle diameter Dv,10 of the hydrophobic strontium titanate, hydrophobic titanium oxide used in each example was 20 nm.

[0166] The volume average primary particle diameter Dv,10 of the hydrophobic strontium titanate, hydrophobic titanium oxide used in each example was 20 nm. 50 The volume average primary particle diameter Dv,10 of the hydrophobic strontium titanate, hydrophobic titanium oxide used in each example was 20 nm.

[0167] The toner of Example 1 was produced as follows.

[0168] First, the raw materials of the toner mother particles were added to a Henshel mixer (manufactured by Mitsui Mining Co., Ltd.) and mixed. The mixture of the raw materials of the toner mother particles was melt-kneaded using a twin-screw extruder. After the melt-kneaded product was cooled, coarse pulverization was performed using a hammer mill. The coarse pulverized product was finely pulverized using a jet mill. The finely pulverized product was classified to obtain the toner mother particles. The volume average particle diameter of the toner mother particles was 6 μm.

[0169] The composition of the raw materials of the toner mother particles is shown below.

[0170]

[0171] Next, the toner of Example 1 was produced by mixing the external additives of the following composition into 100 parts by mass of the toner mother particles of Example 1 using a Henshel mixer.

[0172] Silica particles A 1 part by mass

[0173] Hydrophobic silica β1 2 parts by mass

[0174] Hydrophobic strontium titanate 1 part by mass

[0175] The toner of Example 2 was produced as follows.

[0176] First, the composition of the raw materials of the toner mother particles was changed as follows, and otherwise, the toner mother particles of Example 2 were produced in the same manner as in Example 1. The volume average particle diameter of the toner mother particles of Example 2 was 6 μm.

[0177]

[0178] Charge control agent (polysaccharide inclusion compound containing Al and Mg) 1 part by mass

[0179] Next, the composition of the external additives was changed as follows, and otherwise, the external additives were mixed in the same manner as in Example 1 to produce the toner of Example 2.

[0180] Silica particles B 1 part by mass

[0181] Hydrophobic silica β 1 2 parts by mass

[0182] Hydrophobic strontium titanate 1 part by mass

[0183] The toner of Example 3 was produced as follows.

[0184] First, the composition of the raw material of the toner base particle was changed as follows, and otherwise, the toner base particle of Example 3 was produced in the same manner as in Example 1. The volume average particle diameter of the toner base particle of Example 3 was 6 μm.

[0185]

[0186] Next, the composition of the external additive was changed as follows, and otherwise, the external additive was mixed in the same manner as in Example 1, thereby producing the toner of Example 3.

[0187] Silica particle C 1 part by mass

[0188] Hydrophobic silica β 1 2 parts by mass

[0189] Hydrophobic strontium titanate 1 part by mass

[0190] The toner of Example 4 was produced as follows.

[0191] First, the composition of the raw material of the toner base particle was changed as follows, and otherwise, the toner base particle of Example 4 was produced in the same manner as in Example 1. The volume average particle diameter of the toner base particle of Example 4 was 6 μm.

[0192]

[0193] Next, the composition of the external additive was changed as follows, and otherwise, the external additive was mixed in the same manner as in Example 1, thereby producing the toner of Example 4.

[0194] Silica particle D 1 part by mass

[0195] Hydrophobic silica β 1 2 parts by mass

[0196] Hydrophobic strontium titanate 1 part by mass

[0197] The toner of Example 5 was produced as follows.

[0198] First, the composition of the raw material of the toner base particle was changed as follows, and otherwise, the toner base particle of Example 5 was produced in the same manner as in Example 1. The volume average particle diameter of the toner base particle of Example 5 was 6 μm.

[0199]

[0200] Next, the composition of the additives was changed as follows, except that the additives were mixed in the same manner as in Example 1, thereby producing the colorant of Example 5.

[0201] 1 part by mass of silica particles A

[0202] Hydrophobic silica β1 2 parts by mass

[0203] 1 part by weight of hydrophobic strontium titanate

[0204] The toner of Example 6 is manufactured as follows.

[0205] First, the composition of the raw materials for the toner masterbatch was changed as follows; otherwise, the toner masterbatch of Example 6 was manufactured in the same manner as in Example 1. The volume average particle size of the toner masterbatch of Example 6 was 6 μm.

[0206]

[0207] Next, the composition of the additives was changed as follows, except that the additives were mixed in the same manner as in Example 1, thereby producing the colorant of Example 6.

[0208] Silica particles D 1 part by mass

[0209] Hydrophobic silica β1 2 parts by mass

[0210] 1 part by weight of hydrophobic strontium titanate

[0211] The colorant of Comparative Example 1 was manufactured as follows.

[0212] First, the composition of the raw materials for the toner masterbatch was changed as follows; otherwise, the toner masterbatch of Comparative Example 1 was manufactured in the same manner as in Example 1. The volume average particle size of the toner masterbatch of Comparative Example 1 was 6 μm.

[0213]

[0214] Next, the composition of the additives was changed as follows, except that the additives were mixed in the same manner as in Example 1, thereby producing the colorant of Comparative Example 1.

[0215] Silica particles E 1 part by mass

[0216] Hydrophobic silica β1 2 parts by mass

[0217] 1 part by weight of hydrophobic titanium dioxide

[0218] The colorant of Comparative Example 2 was manufactured as follows.

[0219] First, the composition of the raw material of the toner base particle was changed as follows, and the toner base particle of Comparative Example 2 was produced in the same manner as in Example 1, except for this. The volume average particle diameter of the toner base particle of Comparative Example 2 was 6 μm.

[0220]

[0221] Next, the composition of the external additive was changed as follows, and the toner of Comparative Example 2 was produced by mixing the external additive in the same manner as in Example 1, except for this.

[0222] Silica particles F 1 part by mass

[0223] Hydrophobic silica β 1 2 parts by mass

[0224] Hydrophobic strontium titanate 1 part by mass

[0225] The toner of Comparative Example 3 was produced as follows.

[0226] First, the composition of the raw material of the toner base particle was changed as follows, and the toner base particle of Comparative Example 3 was produced in the same manner as in Example 1, except for this. The volume average particle diameter of the toner base particle of Comparative Example 3 was 6 μm.

[0227]

[0228]

[0229] Next, the composition of the external additive was changed as follows, and the toner of Comparative Example 3 was produced by mixing the external additive in the same manner as in Example 1, except for this.

[0230] Silica particles G 1 part by mass

[0231] Hydrophobic silica β 1 2 parts by mass

[0232] Hydrophobic titanium oxide 1 part by mass

[0233] The toner of Comparative Example 4 was produced as follows.

[0234] First, the composition of the raw material of the toner base particle was changed as follows, and the toner base particle of Comparative Example 4 was produced in the same manner as in Example 1, except for this. The volume average particle diameter of the toner base particle of Comparative Example 4 was 6 μm.

[0235]

[0236] Next, the composition of the external additive was changed as follows, and the toner of Comparative Example 4 was produced by mixing the external additive in the same manner as in Example 1, except for this.

[0237] Silica particles C 1 part by mass

[0238] Hydrophobic silica β 1 2 parts by mass

[0239] Hydrophobic titanium oxide 1 part by mass

[0240] The toner of Comparative Example 5 was produced as follows.

[0241] First, the composition of the raw material of the toner base particle was changed as follows, and otherwise, the toner base particle of Comparative Example 5 was produced in the same manner as in Example 1. The volume average particle diameter of the toner base particle of Comparative Example 5 was 6 μm.

[0242]

[0243] Next, the composition of the external additive was changed as follows, and otherwise, the external additive was mixed in the same manner as in Example 1, thereby producing the toner of Comparative Example 5.

[0244] Silica particle H 1 part by mass

[0245] Hydrophobic silica β 1 2 parts by mass

[0246] Hydrophobic strontium titanate 1 part by mass

[0247] The toner of Comparative Example 6 was produced as follows.

[0248] First, the composition of the raw material of the toner base particle was changed as follows, and otherwise, the toner base particle of Comparative Example 6 was produced in the same manner as in Example 1. The volume average particle diameter of the toner base particle of Comparative Example 6 was 6 μm.

[0249]

[0250] Next, the composition of the external additive was changed as follows, and otherwise, the external additive was mixed in the same manner as in Example 1, thereby producing the toner of Comparative Example 6.

[0251] Silica particle D 1 part by mass

[0252] Hydrophobic silica β 1 2 parts by mass

[0253] Hydrophobic titanium oxide 1 part by mass

[0254] The toner of Comparative Example 7 was produced as follows.

[0255] First, the composition of the raw material of the toner base particle was changed as follows, and otherwise, the toner base particle of Comparative Example 7 was produced in the same manner as in Example 1. The volume average particle diameter of the toner base particle of Comparative Example 7 was 6 μm.

[0256]

[0257] Next, the composition of the external additive was changed as follows, and the external additive was mixed in the same manner as in Example 1, except for this, to produce the toner of Comparative Example 7.

[0258] Silica particles I 1 part by mass

[0259] Hydrophobic silica β1 2 parts by mass

[0260] Hydrophobic strontium titanate 1 part by mass

[0261] The toner of Comparative Example 8 was produced as follows.

[0262] First, the composition of the raw material of the toner base particle was changed as follows, and the toner base particle of Comparative Example 8 was produced in the same manner as in Example 1, except for this. The volume average particle diameter of the toner base particle of Comparative Example 8 was 6 μm.

[0263]

[0264] Next, the composition of the external additive was changed as follows, and the external additive was mixed in the same manner as in Example 1, except for this, to produce the toner of Comparative Example 8.

[0265] Silica particles J 1 part by mass

[0266] Hydrophobic silica β1 2 parts by mass

[0267] Hydrophobic titanium oxide 1 part by mass

[0268] The toner of Comparative Example 9 was produced as follows.

[0269] First, the composition of the raw material of the toner base particle was changed as follows, and the toner base particle of Comparative Example 9 was produced in the same manner as in Example 1, except for this. The volume average particle diameter of the toner base particle of Comparative Example 9 was 6 μm.

[0270]

[0271] Next, the composition of the external additive was changed as follows, and the external additive was mixed in the same manner as in Example 1, except for this, to produce the toner of Comparative Example 9.

[0272] Silica particles K 1 part by mass

[0273] Hydrophobic silica β1 2 parts by mass

[0274] Hydrophobic titanium oxide 1 part by mass

[0275] A method for measuring the carbon number distribution (the proportion of the ester compound of each carbon number) of the ester compound constituting the ester wax will be described.

[0276] Each of the toners was weighed at 0.5 g and stored in a triangular flask. Next, dichloromethane 2 mL was added to the triangular flask to dissolve the toner. Hexane 4 ml was further added to the triangular flask to prepare a mixed solution. The mixed solution was filtered to separate into a filtrate and an insoluble matter. The solvent was distilled off from the filtrate under a nitrogen stream to obtain a precipitate. The carbon number distribution of the ester compound in the ester wax extracted from the toner was measured for the precipitate.

[0277] The proportion of each carbon number of the ester compound was measured by FD-MS "JMS-T100GC (manufactured by JEOL Ltd.)". The measurement conditions were as follows.

[0278] Sample concentration: 1 mg / ml (solvent: chloroform).

[0279] Cathode voltage: -10 kv.

[0280] Spectrum recording interval: 0.4 s.

[0281] Measurement mass range (m / z): 10 to 2000.

[0282] The total of the ion intensity of each carbon number of the ester compound measured was set to 100. The relative value of the ion intensity of each carbon number of the ester compound to the total was calculated. The relative value was taken as the proportion of each carbon number of the ester compound in the ester wax. In addition, the carbon number of the ester compound having the largest relative value was taken as C l .

[0283] The analysis method of the first monomer group and the second monomer group will be described.

[0284] Each of the ester waxes 1 g was subjected to a methanolysis reaction under conditions of a temperature of 70°C and 3 hours. The product after the methanolysis reaction was subjected to mass analysis by FD-MS to calculate the content of each carbon number of the long-chain alkyl carboxylic acid and the content of each carbon number of the long-chain alkyl alcohol.

[0285] The measurement method of the carbon number distribution of the carboxylic acid constituting the first monomer group (the proportion of each carbon number of the carboxylic acid) will be described first.

[0286] The proportion of each carbon number of the carboxylic acid was measured by FD-MS "JMS-T100GC (manufactured by JEOL Ltd.)". The measurement conditions were as follows.

[0287] Sample concentration: 1 mg / ml (solvent: chloroform).

[0288] Cathode voltage: -10 kv.

[0289] Spectrum recording interval: 0.4 s.

[0290] Measurement mass range (m / z): 10 to 2000.

[0291] The total of the ion intensities of the carboxylic acids of each carbon number measured was taken as 100. The relative values of the ion intensities of the carboxylic acids of each carbon number with respect to the total were found. The relative values were taken as the proportions of the carboxylic acids of each carbon number in the ester wax. In addition, the carbon number of the carboxylic acid in which the carbon number was the largest was taken as C n .

[0292] The method of measuring the carbon number distribution of the alcohols (proportions of the alcohols of each carbon number) that constitute the second monomer group will be described.

[0293] The proportions of the alcohols of each carbon number were measured by FD-MS "JMS-T100GC (manufactured by JEOL Ltd.)". The measurement conditions were as described below.

[0294] Sample concentration: 1 mg / ml (solvent: chloroform).

[0295] Cathode voltage: -10 kv.

[0296] Spectrum recording interval: 0.4 s.

[0297] Measurement mass range (m / z): 10 to 2000.

[0298] The total of the ion intensities of the alcohols of each carbon number measured was taken as 100. The relative values of the ion intensities of the alcohols of each carbon number with respect to the total were found. The relative values were taken as the proportions of the alcohols of each carbon number in the ester wax. In addition, the carbon number of the alcohol in which the carbon number was the largest was taken as C m .

[0299] The ester waxes A to O used in each example will be described.

[0300] The carbon number C l of the ester compound in which the content was the largest in the ester waxes A to O, the carbon number C n of the carboxylic acid in which the content was the largest in the first monomer group, and the carbon number C m of the alcohol in which the content was the largest in the second monomer group were as described below, respectively.

[0301] • Ester wax A (C l : 44, C n : 22, C m : 22)

[0302] • Ester wax B (C l : 44, C n : 20, C m : 24)

[0303] • Ester wax C (C l:44, C n :24, C m :20)

[0304] • Ester wax D (C l :44, C n :22, C m :22)

[0305] • Ester wax E (C l :44, C n :20, C m :24)

[0306] • Ester wax F (C l :44, C n :22, C m :22)

[0307] • Ester wax G (C l :42, C n :18, C m :24)

[0308] • Ester wax H (C l :44, C n :18, C m :26)

[0309] • Ester wax I (C l :44, C n :26, C m :18)

[0310] • Ester wax J (C l :44, C n :22, C m :22)

[0311] • Ester wax K (C l :44, C n :20, C m :24)

[0312] • Ester wax L (C1:44, C n :22, C m :22)

[0313] • Ester wax M (C1:46, C n :24, C m :22)

[0314] • Ester wax N (C1:46, C n :22, C m :22)

[0315] • Ester wax O (C1:36, C n :18, Cm :18)

[0316] For ester waxes A to F, H to N, the carbon number distribution of the ester wax had only one peak in the region of 43 or more in the carbon number. For ester waxes G and O, the condition that the carbon number distribution of the ester wax had only one peak in the region of 43 or more in the carbon number was not satisfied. The properties of ester waxes A to O obtained from the measurement results of the mass distribution are shown in Table 1.

[0317] [Table 1]

[0318] [C1] a [b1] [b2] ​ [ca2] d1 [d2] Ester wax A 44 70 4 3 3 15 70 70 Ester wax B 44 75 3 3 2 15 95 70 Ester wax C 44 75 3 2 0 5 90 90 Ester wax D 44 80 3 4 0 5 90 90 Ester wax E 44 65 3 3 5 18 85 82 Ester wax F 44 80 3 4 5 18 90 75 Ester wax G 42 70 5 3 1 15 65 55 Ester wax H 44 60 3 4 5 38 70 70 Ester wax I 44 65 3 3 10 15 60 60 Ester wax J 44 80 3 3 10 40 85 50 Ester wax K 44 70 4 5 10 40 80 50 Ester wax L 44 60 2 3 5 15 95 85 Ester wax M 46 70 3 2 3 5 90 95 Ester wax N 46 70 3 2 3 5 90 95 Ester wax O 44 75 1 1 100 100 100 100

[0319] In Table 1, C1 is the carbon number of the ester compound having the largest content among the ester compounds constituting each ester wax. a is the proportion [mass %] of the ester compound having the carbon number C1 with respect to 100 mass % of the ester wax. b1 is the number [number] of kinds of carboxylic acids in the first monomer group. b2 is the number [number] of kinds of alcohols in the second monomer group. c1 is the proportion [mass %] of the total of carboxylic acids having a carbon number of 18 or less with respect to 100 mass % of the first monomer group. c2 is the proportion [mass %] of the total of alcohols having a carbon number of 18 or less with respect to 100 mass % of the second monomer group. d1 is the proportion [mass %] of carboxylic acids having a carbon number of C n with respect to 100 mass % of the first monomer group. d2 is the proportion [mass %] of alcohols having a carbon number of C m with respect to 100 mass % of the second monomer group.

[0320] The measurement method of the volume average primary particle diameter D 50 will be described.

[0321] A laser diffraction type particle size distribution measuring device (SALD7000 manufactured by Shimadzu Corporation) was used.

[0322] For the silica particles A to K used in each example, D 50 , the degree of association was as described below, respectively.

[0323] • Silica particle A (D 50 : 80 nm, degree of association: 90%)

[0324] • Silica particle B (D 50 : 110 nm, degree of association: 84%)

[0325] • Silica particle C (D 50 : 95 nm, degree of association: 89%)

[0326] • Silica particle D (D 50 : 100 nm, degree of association: 82%)

[0327] • Silica particles E (D 50 : 58 nm, degree of aggregation: 80%)

[0328] • Silica particles F (D 50 : 48 nm, degree of aggregation: 88%)

[0329] • Silica particles G (D 50 : 172 nm, degree of aggregation: 40%)

[0330] • Silica particles H (D 50 : 110 nm, degree of aggregation: 25%)

[0331] • Silica particles I (D 50 : 80 nm, degree of aggregation: 60%)

[0332] • Silica particles J (D 50 : 50 nm, degree of aggregation: 77%)

[0333] • Silica particles K (D 50 : 98 nm, degree of aggregation: 50%)

[0334] The method for measuring the degree of aggregation of the silica particles will be described.

[0335] For each of the toners, an electron microscope photograph was taken by a scanning electron microscope (manufactured by ZEISS). The number of primary particles: nl and the number of secondary particles: n2 were analyzed for the silica particles a adhered to the surface of the toner base particles using image analysis software. The silica particles having a ratio of the short diameter to the long diameter, i.e., the aspect ratio, of less than 0.92 were determined as secondary particles using the image analysis software. In cases where it was difficult to determine by the image analysis software due to overlapping of the silica and the like, it was determined by visual observation. Here, the silica particles a and the silica particles β could be distinguished from each other in the scanning electron microscope, and thus, the degree of aggregation could be calculated for the silica particles a adhered to the surface of the toner base particles.

[0336] Next, the degree of aggregation was calculated based on the following formula, and the average of 20 toners was taken as the degree of aggregation. The results of measuring the degree of aggregation of the silica particles a (i.e., the silica particles A to D) adhered to the toner base particles of each example are shown in Table 2.

[0337] Degree of aggregation (%) = (n2 / (nl + n2)) x 100

[0338] The developers of the examples will be described.

[0339] Each of the toners was stirred in 100 parts by mass of the ferrite carrier by a Turbula mixer, to thereby obtain each of the developers. The ferrite carrier was coated with silicone resin having an average particle diameter of 40 μm on the surface thereof.

[0340] The evaluation method for the storage stability was explained.

[0341] Each of the toners was left at 55°C for 10 hours. Each of the toners left at 55°C for 10 hours was sieved with a sieve, and the toner remaining on the sieve was weighed. The smaller the amount of the toner remaining on the sieve, the better. When the toner remaining on the sieve was 3 g or less, the storage stability of the toner was evaluated as "good" (O). When the toner remaining on the sieve was more than 3 g, the storage stability of the toner was evaluated as "poor" (X).

[0342] The evaluation method for the heat resistance was explained.

[0343] Each of the developers was housed in a toner cartridge. The toner cartridge was disposed in an image forming apparatus for evaluating the heat resistance. The image forming apparatus for evaluating the heat resistance was obtained by installing a thermocouple on a developer of a commercially available e-studio 6530c (manufactured by TOSHIBA TEC). The image forming apparatus for evaluating the heat resistance was used to continuously copy an original having a print rate of 4.0% on A4 paper. While copying, it was confirmed whether or not a conveyance failure or a poor image was generated when the temperature in the developer increased by 2°C, and the temperature at which the conveyance failure or the poor image was first generated was recorded. When the temperature at which the conveyance failure or the poor image was first generated was 47°C or higher, the heat resistance of the toner was evaluated as "good" (O). When the temperature at which the conveyance failure or the poor image was first generated was lower than 45°C, the heat resistance of the toner was evaluated as "poor" (X).

[0344] The evaluation method for the low-temperature fixing property was explained.

[0345] Each of the developers was housed in a toner cartridge. The toner cartridge was disposed in an image forming apparatus for evaluating the low-temperature fixing property. The image forming apparatus for evaluating the low-temperature fixing property was obtained by modifying a commercially available e-studio 6530c (manufactured by TOSHIBA TEC) so that it could change and set the fixing temperature in a range from 100°C to 200°C at a scale of 0.1°C. Using the image forming apparatus for evaluating the low-temperature fixing property, the fixing temperature was set to 150°C, and 10 copies were obtained at a copy rate of 10 copies / minute. The fixing temperature was changed at a scale of 0.1°C, and the fixing temperature at which the toner was first fixed was recorded. When the fixing temperature at which the toner was first fixed was 150°C or higher, the low-temperature fixing property of the toner was evaluated as "good" (O). When the fixing temperature at which the toner was first fixed was lower than 150°C, the low-temperature fixing property of the toner was evaluated as "poor" (X). 2The temperature of the fixing device was decreased by 1°C, and the same operation as described above was performed to obtain a solid image. This operation was repeated to obtain the lower limit of the fixing temperature at which no image peeling occurred on the solid image, and the lower limit was used as the minimum fixing temperature of the toner. When the minimum fixing temperature was 120°C or less, the low temperature fixing property of the toner was evaluated as acceptable (O). When the minimum fixing temperature exceeded 120°C, the low temperature fixing property of the toner was evaluated as unacceptable (X).

[0346] The evaluation method of the charge amount will be described.

[0347] A commercially available e-studio 5005AC (manufactured by TOSHIBA TEC) was used to continuously copy a document having a print rate of 8.0% on 200,000 sheets of A4 paper. Then, the toner deposited on the lower side of the magnetic roller of the developing device was sucked up with a vacuum cleaner, and the amount of the deposited toner was measured as the amount of contaminated toner. When the amount of contaminated toner was 170 mg or less, the charge amount of the toner was evaluated as acceptable (O). When the amount of contaminated toner exceeded 170 mg, the charge amount of the toner was evaluated as unacceptable (X).

[0348] [Table 2]

[0349]

[0350] The evaluation results of the low temperature fixing property, the storage property, the heat resistance, and the charge amount of the toners of Examples 1 to 6 are shown in Table 2.

[0351] The toners of Examples 1 to 6 had excellent low temperature fixing property, storage property, and heat resistance. In addition, the toners had a small amount of contamination, and the charge amount was sufficiently maintained even at a high temperature and high humidity in the image forming apparatus.

[0352] In contrast, the toners of Comparative Examples 1 to 9 did not simultaneously satisfy the acceptable standards in terms of the low temperature fixing property, the storage property, the heat resistance, and the charge amount.

[0353] Next, the relationship between the degree of aggregation of the silica particles and the adhesion strength was measured.

[0354] Specifically, the adhesion strength of the external additive was measured for the toner in which the degree of aggregation of the silica particles was changed. First, a cyclone collector was used to apply a high air pressure to the toner to cause the external additive to be detached. Fluorescent X-ray (XRF) analysis was performed on the toner before and after the external additive was detached to measure the peak intensity of Si elements on the surface of the toner base particles.

[0355] Adhesion strength (%) = ((peak intensity of Si elements after the external additive was detached) / (peak intensity of Si elements before the external additive was detached)) x 100

[0356] The closer the ratio of the peak intensity of the Si element before and after the external agent is detached to 1, the greater the adhesion strength.

[0357] Figure 2 The results of measuring the relationship between the degree of aggregation of the silica particles and the adhesion strength of the external agent are shown. As shown in Figure 2 a correlation between the degree of aggregation of the silica particles and the adhesion strength was confirmed.

[0358] If the degree of aggregation of the silica particles is 80% or more, it is known that the adhesion strength of the external agent becomes high. Therefore, if the degree of aggregation of the silica particles is 80% or more, it can be considered that the charge amount of the toner is easily maintained.

[0359] Although several embodiments have been described, these embodiments are presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included within the scope and spirit of the invention, and are included within the scope of the invention and equivalents thereof recited in the claims.

Claims

1. A toner, characterized by, a toner base particle, and an external additive attached to the surface of the toner base particle, the toner base particle contains a crystalline polyester resin and an ester wax, the ester wax is a polycondensate of a first monomer group and a second monomer group, the first monomer group contains at least three or more carboxylic acids, and the second monomer group contains at least two or more alcohols, The maximum content of the carboxylic acid in the first monomer group has a carbon atom number C n of 19 to 28, and the ratio of the carboxylic acid with respect to 100 mass% of the first monomer group is 70 to 95 mass%. n ​ the proportion of the carboxylic acid having 18 or less carbon atoms in the first monomer group is 5% by mass or less relative to 100% by mass of the first monomer group, The maximum content of the second monomer group is a C m alcohol having a carbon atom number C m of 19 to 28, and the ratio of the alcohol is 70 to 90 mass% with respect to 100 mass% of the second monomer group. the proportion of the alcohol having 18 or less carbon atoms in the second monomer group is 20% by mass or less relative to 100% by mass of the second monomer group, The external agent contains silica particles having a volume average primary particle diameter D 50 of 70 to 120 nm, the silica particle contains primary particles of silica and secondary particles in which two or more primary particles of silica are combined, the degree of association of the silica particle calculated from the following formula is 80% or more, Degree of association (%) = (n2 / (n1 + n2)) x 100 In the formula, n1 is the number of the primary particles measured for one toner base particle, and n2 is the number of the secondary particles measured for one toner base particle.

2. The toner according to claim 1, wherein In the ester compound constituting the ester wax, the ester compound having the largest content has a carbon atom number C l of 43 to 56. The proportion of the ester compound having the carbon atom number C l of 43 to 56 is 65 to 90 mass% with respect to 100 mass% of the ester wax.

3. The toner according to claim 1 or 2, wherein the external additive further contains either one or both of strontium titanate and titanium oxide.

4. The toner according to claim 1 or 2, wherein the content of the external additive is 2 to 15 parts by mass relative to 100 parts by mass of the toner base particle.

5. A toner cartridge, characterized by, The toner according to any one of claims 1 to 4 is accommodated.

6. An image forming apparatus characterized by comprising: The toner according to any one of claims 1 to 4 is accommodated.

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