Toner, toner cartridge, image forming apparatus

Abstract

The present invention provides toner, a toner cartridge, and an image forming apparatus, the toner having excellent low-temperature fixing properties, excellent heat resistance even in the case of being reused, being able to sufficiently maintain a charge amount, and having difficulty in reducing an image density. The toner cartridge houses the toner. The toner of the embodiment has toner parent particles and an external additive. The external additive contains silica particles A, B, and C having particle diameters of 10 to 14 nm, 40 to 70 nm, and 90 to 150 nm, respectively. The content of each of the silica particles A, B, and C is 0.1 to 0.8 parts by mass, 0.3 to 1.2 parts by mass, and 0.3 to 1.2 parts by mass, respectively, relative to 100 parts by mass of the toner parent particles. The total content of the silica particles A, B, and C is 3.0 parts by mass or less relative to 100 parts by mass of the toner parent particles. The ratio of the content of the silica particles B and C to the content of the silica particles A is 1.0 to 5.0. The volume average primary particle diameter Dv50 of the toner is 5.5 to 11.0 μm. 50 is 5.5 to 11.0 μm.

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.

[0003] However, the heat resistance of the toner containing the crystalline polyester resin is insufficient. Therefore, the toner containing the crystalline polyester resin is likely to form a soft block at a high temperature. The flowability of the toner after the soft block is low, and thus causes poor developer conveyance in the image forming apparatus.

[0004] In addition, the hygroscopicity of the crystalline polyester resin is high. Therefore, the toner is likely to decrease in the charge amount, and the flying amount in the image forming apparatus is decreased.

[0005] Thus, in the toner containing the crystalline polyester resin, it is difficult to simultaneously maintain the low-temperature fixing property, the flowability, and the flying amount.

[0006] The use of the external agent is effective for the improvement of the heat resistance of the toner and the maintenance of the charge amount. However, in the case where the toner image is recycled, there is a case where the toner from which the external agent is peeled off is supplied again to the developing device. Therefore, it is more difficult to improve the heat resistance and maintain the charge amount when the toner is recycled.

[0007] On the other hand, if the charge amount of the toner is too high, the transfer of the toner at the time of image formation is insufficient. As a result, the image density can be decreased. SUMMARY

[0008] The present application has been achieved in order to solve the above-described problems, and an object of the present application is to provide a toner, a toner cartridge containing the toner, and an image forming apparatus, in which the low-temperature fixing property of the toner is excellent, the heat resistance of the toner is excellent even in the case where the toner is recycled, the charge amount of the toner is sufficiently maintained, and the image density is not easily decreased.

[0009] The toner of the embodiment has a toner parent particle and an external agent. The external agent is attached to the surface of the toner parent particle. The toner parent particle contains a crystalline polyester resin and an ester wax.

[0010] 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 three or more kinds of alcohols.

[0011] 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 proportion of the alcohol having a carbon atom number of C nThe carbon atom number C is the carbon atom number of the alcohol having the largest content in the second monomer group. The proportion of the alcohol having a carbon atom number of 18 or less in the second monomer group is 20% by mass or less with respect to 100% by mass of the second monomer group.

[0012] The carbon atom number C is the carbon atom number of the alcohol having the largest content in the second monomer group. The proportion of the alcohol having a carbon atom number of 18 or less in the second monomer group is 20% by mass or less with respect to 100% by mass of the second monomer group. m The carbon atom number C is the carbon atom number of the alcohol having the largest content in the second monomer group. The proportion of the alcohol having a carbon atom number of 18 or less in the second monomer group is 20% by mass or less with respect to 100% by mass of the second monomer group. m The carbon atom number C is the carbon atom number of the alcohol having the largest content in the second monomer group. The proportion of the alcohol having a carbon atom number of 18 or less in the second monomer group is 20% by mass or less with respect to 100% by mass of the second monomer group.

[0013] The silica particle A has a particle diameter r A of 10 to 14 nm. The silica particle B has a particle diameter r B of 40 to 70 nm. The silica particle C has a particle diameter r C of 90 to 150 nm.

[0014] The content of the silica particle A is 0.1 to 0.8 parts by mass with respect to 100 parts by mass of the toner base particle.

[0015] The content of the silica particle B is 0.3 to 1.2 parts by mass with respect to 100 parts by mass of the toner base particle.

[0016] The content of the silica particle C is 0.3 to 1.2 parts by mass with respect to 100 parts by mass of the toner base particle.

[0017] The total of the content of the silica particle A, the content of the silica particle B, and the content of the silica particle C is 3.0 parts by mass or less with respect to 100 parts by mass of the toner base particle.

[0018] The ratio of the content of the silica particle B to the content of the silica particle A is 1.0 to 5.0.

[0019] The ratio of the content of the silica particle C to the content of the silica particle A is 1.0 to 5.0.

[0020] The volume average primary particle diameter D 50 of the toner is 5.5 to 11.0 μm. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a drawing showing an example of the schematic structure of the image forming apparatus of the embodiment.

[0022] Figure 2 is a perspective view of a developing device of the image forming apparatus of Figure 1 .

[0023] Figure 3 is Figure 1 a side view of a developing device of an image forming apparatus.

[0024] Figure 4 is a drawing showing an example of a schematic structure of an image forming apparatus of another embodiment.

[0025] Figure 5 is Figure 4 a perspective view of a modification example of a developing device of an image forming apparatus of

[0026] Symbol explanation

[0027] 1: image forming apparatus; 2: scanner section; 3: paper discharge section; 4: paper feed cassette; 10: intermediate transfer belt; 11Y, 11M, 11C, 11K: image forming positions; 12Y, 12M, 12C, 12K: photosensitive drums; 13Y, 13M, 13C, 13K: charge rollers; 14Y, 14M, 14C, 14K: developing devices; 30: fixing device; 31: manual paper feed mechanism; 64Y: developing device; 101: copier main body; 102: photosensitive drum; 103: charge roller; 104: laser unit; 105: developing device; 106: transfer charger; 107: cleaning device; 108: replenishment container; 110: recycling mechanism; 111: developing container; 112: developing roller; 114, 115: first and second partition walls; 116 to 118: first to third chambers; 120 to 122: first to third mixers; 123: fresh toner receiving section; 124: recycled toner receiving section; 125 to 128: first to fourth communication sections; 129: toner concentration detector. DETAILED DESCRIPTION

[0028] Hereinafter, the toner of the embodiment will be described.

[0029] The toner of the embodiment has toner base particles and an external additive.

[0030] The toner base particles will be described.

[0031] The toner base particles of the embodiment contain a crystalline polyester resin and an ester wax. In addition to the crystalline polyester resin and the ester wax, the toner base particles of the embodiment can contain other binder resins other than the crystalline polyester resin, a colorant. The toner base particles of the embodiment can further contain other components other than the crystalline polyester resin, the ester wax, the other binder resins, and the colorant, as long as the effects disclosed in the embodiment can be obtained.

[0032] The crystalline polyester resin will be described.

[0033] The crystalline polyester resin functions as a binder resin. Since the toner parent particles contain the crystalline polyester resin, the low-temperature fixing property of the toner of the embodiments is excellent.

[0034] In the embodiments, 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".

[0035] 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.

[0036] 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-butenediol, polyoxypropylene, polyoxyethylene, glycerol, pentaerythritol, trimethylolpropane, or the like can be exemplified. As the dihydric or more alcohol, 1,4-butanediol and 1,6-hexanediol are preferred.

[0037] 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, esters thereof, or the like can be exemplified.

[0038] 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 preferred.

[0039] 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 or in combination of two or more.

[0040] 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 more 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 offset resistance of the toner is also excellent.

[0041] In the present specification, the weight average molecular weight is a value in terms of polystyrene obtained by gel permeation chromatography.

[0042] 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 higher than the lower limit of the range, the heat resistance of the toner is more excellent. If the melting point of the crystalline polyester resin is equal to or lower than the upper limit of the range, the low-temperature fixing property of the toner is more excellent.

[0043] The melting point of the crystalline polyester resin can be measured by, for example, a differential scanning calorimeter (DSC).

[0044] The other binder resin will be described.

[0045] As the other binder resin, for example, a non-crystalline polyester resin, a styrene-based resin, an ethylene-based resin, an acrylic resin, a phenolic resin, an epoxy resin, an allyl phthalate resin, a polyamide resin, a maleic acid resin, and the like can be exemplified. However, the other binder resin is not limited to these examples.

[0046] The other binder resin can be used alone as any one kind or two or more kinds in combination.

[0047] From the viewpoint 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.

[0048] 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.

[0049] 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-butanediene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, bisphenol A, hydrogenated bisphenol A, an alkylene oxide adduct of bisphenol A, and the like can be exemplified. However, the dihydric alcohol is not limited to these examples.

[0050] As the epoxy alkane adduct of bisphenol A, a compound obtained by adding an epoxy alkane having a carbon atom number of 2 to 3 at an average of 1 to 10 moles to bisphenol A can be exemplified. As the epoxy alkane 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.

[0051] As the dihydric alcohol, an epoxy alkane 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.

[0052] The other binder resin is obtained by, for example, polymerizing a vinyl polymerizable monomer alone or a plurality of them.

[0053] 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.

[0054] As the aromatic vinyl monomer, for example, styrene, methylstyrene, methoxystyrene, phenylstyrene, chlorostyrene, derivatives thereof can be exemplified.

[0055] As the ester monomer, for example, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, derivatives thereof can be exemplified.

[0056] As the carboxylic acid-containing monomer, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid, derivatives thereof can be exemplified.

[0057] As the amine monomer, for example, amino acrylate, acrylamide, methacrylamide, vinylpyridine, vinylpyrrolidone, derivatives thereof can be exemplified.

[0058] 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 kinds of aids such as a chain transfer agent, a crosslinking agent, a polymerization initiator, a surfactant, a coagulant, a pH adjustor, an antifoaming agent, and the like can be used.

[0059] An ester wax is described.

[0060] 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.

[0061] The ester wax is a polycondensate of a first monomer group and a second monomer group.

[0062] The first monomer group will be described.

[0063] The first monomer group contains at least three or more kinds of carboxylic acids. The number of kinds of carboxylic acids in the first monomer group is preferably seven or less, more preferably five or less, from the viewpoint of easy availability of ester wax.

[0064] 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, further preferably 20 to 24. If the number of carbon atoms C n is the lower limit value or more, the heat resistance of ester wax is more improved. If the number of carbon atoms C n is the upper limit value or less, the low-temperature fixing property of toner is more excellent.

[0065] 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, more preferably 85 to 95% by mass, with respect to 100% by mass of the first monomer group. The proportion of the carboxylic acid having the number of carbon atoms C n is the lower limit value or more, and therefore the mode of the distribution of the number of carbon atoms of ester wax is sufficiently located on the high number of carbon atoms side. As a result, the heat resistance of toner is excellent. The proportion of the carboxylic acid having the number of carbon atoms C n is the upper limit value or less, and therefore ester wax is easily obtained.

[0066] 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, 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, ester wax is easily obtained. The proportion of the carboxylic acid having the number of carbon atoms of 18 or less is the upper limit value or less, and therefore the proportion of ester compounds having a relatively low molecular weight in ester wax is reduced. As a result, the heat resistance of toner is excellent.

[0067] The content of the carboxylic acid having each number of carbon atoms in the first monomer group can be determined by, for example, subjecting the product after a methanolysis reaction of ester wax to mass analysis using FD-MS (Field Desorption Mass Spectrometry). The total of the ion intensities of the carboxylic acid having each number of carbon atoms in the product measured using FD-MS is taken as 100. The relative value of the ion intensity of the carboxylic acid having each number of carbon atoms with respect to the total is calculated. This relative value is taken as the content of the carboxylic acid having each number of carbon atoms in the first monomer group. In addition, the number of carbon atoms of the carboxylic acid having the largest relative value is taken as Cn .

[0068] As the carboxylic acid in the first monomer group, a long chain carboxylic acid, preferably a long chain alkyl carboxylic acid, is preferred from the viewpoint of easy availability of the ester wax. The long chain carboxylic acid is appropriately selected so that the ester wax satisfies the prescribed requirements.

[0069] As the long chain carboxylic acid, a long chain carboxylic acid having 19 to 28 carbon atoms is preferred, and a long chain carboxylic acid having 20 to 24 carbon atoms is more preferred. If the number of carbon atoms of the long chain carboxylic acid is equal to or greater than the lower limit value, the heat resistance of the ester wax is more improved. If the number of carbon atoms of the long chain carboxylic acid is equal to or smaller than the upper limit value, the low temperature fixing property of the toner is more excellent.

[0070] As the long chain alkyl carboxylic acid, for example, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, and the like can be exemplified.

[0071] The second monomer group will be described.

[0072] The second monomer group contains at least three or more alcohols. From the viewpoint of easy availability of the ester wax, the number of types of alcohols in the second monomer group is preferably five or less.

[0073] Here, the number of carbon atoms of the alcohol having the largest content in the second monomer group is set to C m . The number of carbon atoms C m is preferably 19 to 28, more preferably 20 to 24, and further preferably 20 to 22. If the number of carbon atoms C m is equal to or greater than the lower limit value, the heat resistance of the ester wax is improved. If the number of carbon atoms C m is equal to or smaller than the upper limit value, the low temperature fixing property of the toner is more excellent.

[0074] The proportion of the alcohol having the largest content and having the number of carbon atoms C m is 70 to 90% by mass, preferably 80 to 90% by mass, and more preferably 85 to 90% by mass, with respect to 100% by mass of the second monomer group. The proportion of the alcohol having the number of carbon atoms C m is equal to or greater than the lower limit value, and therefore the mode of the distribution of the number of carbon atoms of the ester wax is sufficiently located on the high number of carbon atoms side. As a result, the heat resistance of the toner is excellent. If the proportion of the alcohol having the number of carbon atoms C m is equal to or smaller than the upper limit value, the ester wax is easily obtained.

[0075] The proportion of the alcohol having 18 or less carbon atoms 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 18 or less carbon atoms is the lower limit value or more, the ester wax is easily obtained. The proportion of the alcohol having 18 or less carbon atoms is the upper limit value or less, and thus the proportion of the ester compound having a relatively low molecular weight in the ester wax is reduced. As a result, the toner has excellent heat resistance.

[0076] 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. The 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 .

[0077] As the alcohol in the second monomer group, a long-chain alcohol, and more preferably a long-chain alkyl alcohol, is preferable from the viewpoint 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 19 to 28 carbon atoms, and more preferably a long-chain alcohol having 20 to 22 carbon atoms, is 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 toner has more excellent heat resistance. 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.

[0078] As the long-chain alkyl alcohol, for example, the following can be given: palmitol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, ceryl alcohol, montanyl alcohol.

[0079] In the ester wax of the embodiment, it is preferable that an ester compound having the largest content in the ester compounds constituting the ester wax of the embodiment have a carbon number of C l . 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 heat resistance of the ester wax is more excellent. If the carbon number C l is the upper limit value or less, the ester wax is easily obtained.

[0080] The ester compound having the carbon number C l is represented by the following formula (I).

[0081] R 1 COOR 2 (I)

[0082] R in equation (I) 1 and R 2 It is an alkyl group. R 1 and R 2 The total number of carbon atoms is preferably 42 or more, more preferably 42 to 55, further preferably 42 to 51, particularly preferably 43 to 45, and most preferably 43. If R 1 and R 2 If the total number of carbon atoms is above the lower limit, the heat resistance of the toner is even better. If R 1 and R 2 If the total number of carbon atoms is below the aforementioned upper limit, then ester waxes are easily obtained. 1 The number of carbon atoms can be adjusted to C. n The number of carbon atoms in a carboxylic acid (C) n To control. R 2 The number of carbon atoms can be adjusted to C. m The number of carbon atoms in the alcohol (C) m To control.

[0083] The number of carbon atoms is C l The proportion of the ester compound relative to 100% by mass of the ester wax is preferably 65% ​​by mass or more, more preferably 65-90% by mass, further preferably 70-90% by mass, and particularly preferably 80-90% by mass. If the number of carbon atoms is C... l When the proportion of ester compounds is above the lower limit, the maximum peak of the carbon number distribution of the ester wax becomes significantly higher. As a result, the heat resistance of the toner is more excellent. If the carbon number is C... l When the proportion of ester compounds is below the upper limit, ester waxes are easily obtained.

[0084] The carbon number distribution of the ester wax in the embodiment preferably has only one maximum peak in the region with 43 or more carbon atoms. In this case, the proportion of ester compounds with relatively low molecular weight decreases. As a result, the heat resistance of the toner is more excellent.

[0085] In the carbon number distribution of the ester wax in the embodiment, the location of the maximum peak is preferably in the region with 43 to 56 carbon atoms, more preferably in the region with 44 to 52 carbon atoms, even more preferably in the region with 44 to 46 carbon atoms, and most preferably with 44 carbon atoms. If the location of the maximum peak is in the region with a carbon number of carbon atoms above the lower limit, the heat resistance of the toner is more excellent. If the location of the maximum peak is in the region with a carbon number of carbon atoms below the upper limit, the ester wax is easier to obtain.

[0086] The content of each carbon number of the ester compound in the ester wax can be determined by, for example, mass analysis using FD-MS. The total of the ion intensity of each carbon number of the ester compound in the ester wax measured using FD-MS is taken as 100. The relative value of the ion intensity of each carbon number of the ester compound with respect to the total is calculated. The relative value is taken as the content 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 is taken as C l .

[0087] The method for producing the ester wax will be described.

[0088] The ester wax can be produced by, for example, subjecting a long-chain carboxylic acid to an esterification reaction with a long-chain alcohol. In the esterification reaction, at least three or more kinds of long-chain alkyl carboxylic acids and at least three or more kinds of long-chain alkyl alcohols are preferably used from the viewpoint of easily obtaining an ester wax satisfying the prescribed requirements. The carbon number distribution of the ester compound contained in the ester wax can be adjusted by adjusting the use amount of each of the at least three kinds of long-chain alkyl carboxylic acids and the at least three kinds of long-chain alkyl alcohols. The esterification reaction is preferably performed while being heated under a stream of nitrogen.

[0089] The esterification reaction product can be purified by dissolving the product in a solvent such as methanol or toluene, adding an aqueous alkali solution such as an aqueous sodium hydroxide solution, and separating the organic layer and the 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.

[0090] The colorant will be described.

[0091] The colorant is not particularly limited. Examples include pigments such as carbon black, cyan, yellow, and magenta, and dyes.

[0092] As the carbon black, examples include aniline black, lamp black, acetylene black, furnace black, thermal black, channel black, and Ketjen black.

[0093] As the pigments and dyes, examples include 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.

[0094] As colorants, according to the markings in the color index, examples include: CI Pigment Black 1, 6, 7; CI Pigment Yellow 1, 12, 14, 17, 34, 74, 83, 97, 155, 180, 185; CI Pigment Orange 48, 49; CI 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, CI Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:5, 15:6, 75, 76, 79, CI Pigment Green 1, 7, 8, 36, 42, 58, CI Pigment Violet 1, 19, 42, CI Acid Red 52, etc. However, the colorant is not limited to these examples.

[0095] Colorants can be used alone or in combination of two or more.

[0096] The other ingredients are described.

[0097] Other components include: charge control agents, surfactants, basic compounds, coagulants, pH adjusters, antioxidants, and other additives. However, additives are not limited to these examples. Any one additive can be used alone, or two or more can be used in combination.

[0098] The charge control agent is explained.

[0099] When the toner master particles contain a charge control agent, the toner is easily transferred to recording media such as paper. Examples of charge control agents include: metal azo compounds, metal salicylic acid derivative compounds, metal oxide hydrophobic treatments, and polysaccharide inclusion compounds. For metal azo compounds, complexes or complex salts of iron, cobalt, or chromium, or mixtures thereof, are preferred. For metal salicylic acid derivative compounds and metal oxide hydrophobic treatments, complexes or complex salts of zirconium, zinc, chromium, or boron, or mixtures thereof, are preferred. For polysaccharide inclusion compounds, inclusion compounds containing aluminum (Al) and magnesium (Mg) polysaccharides are preferred.

[0100] The composition of the toner master particles is explained.

[0101] 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% relative to 100 mass% of the toner base particle. 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 offset resistance of the toner is excellent.

[0102] 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% relative to 100 mass% of the toner base particle. If the content of the ester wax is equal to or greater than the lower limit value, the heat resistance of the toner is 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 maintained sufficiently.

[0103] In the case where the toner base particle contains the 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% relative to 100 mass% of the toner base particle. 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 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.

[0104] In the case where the toner base particle contains the colorant, the content of the colorant is preferably 2 to 13 mass%, and more preferably 3 to 8 mass% relative to 100 mass% of the toner base particle. 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.

[0105] The external additive is described.

[0106] The external additive contains specific silica particles A, silica particles B, and silica particles C. The particle diameter r A of the silica particles A is 10 to 14 nm. The particle diameter r B of the silica particles B is 40 to 70 nm. The particle diameter r C of the silica particles C is 90 to 150 nm.

[0107] Thus, in the toner of the embodiment, the external additive contains the silica particles A, the silica particles B, and the silica particles C having mutually different particle diameters. Therefore, it is considered that, if the external additive is taken out from the toner of the embodiment, and the particle diameter distribution of the external additive is measured, there are at least three peaks of the silica particles.

[0108] In the particle size distribution, at least one of the three maximum peaks is preferably present in each of the ranges of 10 to 14 nm, 40 to 70 nm, and 90 to 150 nm. In this case, the particle size r A may be the mode (most frequent value) in the range of 10 to 14 nm in the particle size distribution. In addition, the particle size r B may be the mode (most frequent value) in the range of 40 to 70 nm in the particle size distribution. In addition, the particle size r C may be the mode (most frequent value) in the range of 90 to 150 nm in the particle size distribution.

[0109] The particle size of each of the silica particles can be measured, for example, by a laser diffraction type particle size distribution measuring device.

[0110] The particle size r A is relatively small. Therefore, the flowability and the charging property of the toner are improved by the silica particles A. As a result, even in the case where the toner of the embodiment is reused, the heat resistance is excellent, and the charge amount can be sufficiently maintained.

[0111] However, when the surface of the toner particles is subjected to pressure in the developing device, the silica particles A are easily detached from the surface of the toner or easily embedded. Therefore, the silica particles C, which have a relatively large particle size r C protect the silica particles A from the pressure.

[0112] However, the silica having a large particle size generally has a weak charging imparting ability. Therefore, the charging imparting ability of the silica particles A can be impaired and the charge amount can be reduced due to the presence of the silica particles C. Therefore, in addition to the silica particles C, the silica particles B, which have a particle size r B protect the silica particles A from the pressure. At the same time, by the silica particles B, the charge amount and the toner flying amount can be sufficiently maintained.

[0113] The contents of these silica particles A, silica particles B, and silica particles C are each within a specific range. Therefore, even in the case where the toner of the embodiment is reused, the heat resistance is excellent, the charge amount is sufficiently maintained, and the image density is not easily reduced.

[0114] The particle size r A is 10 to 14 nm, preferably 11 to 13 nm, and more preferably 11 to 12 nm. The particle size r A is greater than the lower limit value, and therefore the charge amount of the toner of the embodiment is high, and the flying amount of the toner can be sufficiently maintained. The particle size r ABelow the upper limit value, therefore, it is difficult for the silica particles A to be embedded in the toner parent particles. Thus, the flowability of the toner is improved. As a result, the flying amount of the toner can also be sufficiently maintained.

[0115] The particle diameter r B is 40 to 70 nm, preferably 45 to 65 nm, and more preferably 50 to 60 nm. The particle diameter r B Above the lower limit value, therefore, the silica particles B can sufficiently protect the silica particles A. Thus, the silica particles A are difficult to be detached, and the flowability is sufficiently exhibited.

[0116] The conveyance failure is reduced. The particle diameter r B Below the upper limit value, therefore, the charging amount of the toner can be sufficiently maintained, and the flying amount of the toner can also be sufficiently maintained.

[0117] The particle diameter r C is 90 to 150 nm, preferably 100 to 140 nm, and more preferably 115 to 130 nm. The particle diameter r C Above the lower limit value, therefore, the silica particles C can sufficiently protect the silica particles A. Thus, the silica particles A are difficult to be detached, the flowability is sufficiently exhibited, and the conveyance failure is reduced. The particle diameter r C Below the upper limit value, therefore, the charging amount and the flying amount of the toner of the embodiment are difficult to be reduced.

[0118] The content w of the silica particles A A is 0.1 to 0.8 parts by mass, preferably 0.3 to 0.6 parts by mass, and more preferably 0.4 to 0.5 parts by mass, with respect to 100 parts by mass of the toner parent particles. The content w of the silica particles A A Above the lower limit value, therefore, the charging amount of the toner of the embodiment is sufficiently high, and the flying amount of the toner can be sufficiently maintained. In addition, even in the case of being reused, the flowability of the toner is good, and the conveyance failure is reduced. The content w of the silica particles A A Below the upper limit value, therefore, the charging amount of the toner does not become excessively high. Thus, the image density at the time of image formation can be sufficiently ensured, and the image density is not easily reduced.

[0119] The content w of the silica particles B B is 0.3 to 1.2 parts by mass, preferably 0.5 to 1.0 parts by mass, and more preferably 0.7 to 0.9 parts by mass, with respect to 100 parts by mass of the toner parent particles. The content w of the silica particles B B Above the lower limit value, therefore, the charging amount of the toner is high, and the flying amount of the toner can be sufficiently maintained. The content w of the silica particles B BBelow the upper limit value, the charge amount of the toner can be sufficiently maintained, and the flying amount of the toner can also be sufficiently maintained.

[0120] The content w of the silica particles C C The content w of the silica particles C is 0.3 to 1.2 parts by mass, preferably 0.5 to 1.0 parts by mass, and more preferably 0.7 to 0.8 parts by mass, with respect to 100 parts by mass of the toner base particles 100. C Above the lower limit value, the silica particles A are less likely to be detached, and the fluidity is sufficiently exhibited, and the conveyance failure is reduced. The content w of the silica particles C C Below the upper limit value, the charge amount and the flying amount of the toner of the embodiment are less likely to decrease.

[0121] The total w of the content of the silica particles A, the content of the silica particles B, and the content of the silica particles C A+B+C The total w of the content of the silica particles A, the content of the silica particles B, and the content of the silica particles C is 3.0 parts by mass or less, preferably 1 to 3 parts by mass, and more preferably 1.8 to 2.4 parts by mass, with respect to 100 parts by mass of the toner base particles 100. If the total w of the content A+B+C Above the lower limit value, the toner base particles are protected by the external additive at the time of storage, and the storage properties of the toner are also excellent. The total w of the content A+B+C Below the upper limit value, the toner is sufficiently fused at the time of fixation, and the low-temperature fixing property is improved.

[0122] The ratio (B / A) of the content of the silica particles B to the content of the silica particles A is 1.0 to 5.0, preferably 2.0 to 4.5, and more preferably 3.0 to 4.0. Above the lower limit value of the ratio (B / A), the silica particles A are less likely to be detached, and the fluidity is sufficiently exhibited, and the conveyance failure is reduced. Below the upper limit value of the ratio (B / A), the charge amount of the toner can be sufficiently maintained, and the flying amount of the toner can also be sufficiently maintained.

[0123] The ratio (C / A) of the content of the silica particles C to the content of the silica particles A is 1.0 to 5.0, preferably 1.5 to 4.0, and more preferably 2.0 to 3.0. Above the lower limit value of the ratio (C / A), the silica particles A are less likely to be detached, and the fluidity is sufficiently exhibited, and the conveyance failure is reduced. Below the upper limit value of the ratio (C / A), the charge amount and the flying amount of the toner of the embodiment are less likely to decrease.

[0124] Each of the silica particles A, B, and C is preferably a primary particle of silica. The primary particle of silica is attached to the surface of the toner base particle in a monodispersed state. Therefore, the control of the charge amount of the easy toner, the reduction of the flying amount, and the reduction of the image density become less. Here, the primary particle of silica refers to a one-particle particle formed of silica. The primary particle of silica is preferably spherical, and more preferably a true sphere.

[0125] As the external agent, a secondary particle of silica can exist on the surface of the toner base particle, in addition to the silica particle, as long as the effects disclosed in the embodiments can be obtained within a range. The secondary particle of silica is a combination of two or more primary particles of silica. Therefore, the secondary particle is formed in an amorphous state. The specific shape of the secondary particle is not particularly limited. The secondary particle can be in a polyprism shape, a polyhedral shape, or an ellipsoidal shape.

[0126] As the silica particles A, B, and C, from the aspect of more sufficiently maintaining the charge amount of the toner, a wet-process silica is preferable. The wet-process silica can be produced, for example, by using sodium silicate using silica sand as a raw material, neutralizing an aqueous solution containing the sodium silicate to precipitate silica, and filtering and drying the solution (liquid-phase method). In correspondence thereto, it is known that sintered silica (dry-process silica) is obtained by reacting silicon tetrachloride in a high-temperature flame. If the wet-process silica is used as the external agent of the toner, the charge amount of the toner is easily maintained compared to the sintered silica which generally has a low moisture content.

[0127] As the silica particles A, B, and C, from the aspect of more excellent heat resistance of the toner, a hydrophobic silica particle is preferable for each. The hydrophobic silica particle is obtained, for example, by hydrophobically treating the silanol group on the surface of the wet-process silica using silane, silicone, or the like. If the hydrophobic silica particle is used as the external agent of the toner, the adhesion to the toner base particle becomes better.

[0128] The degree of hydrophobization of the hydrophobic silica can be measured, for example, by the following method.

[0129] Ion-exchanged water 50 ml and a sample 0.2 g were put in a beaker, and then methanol was added from a burette while stirring with an electromagnetic stirrer. Then, the powder gradually settled as the concentration of methanol in the beaker increased, and the volume % of methanol in the mixed solution of methanol and ion-exchanged water at the end point at which the total amount of the settled methanol was measured as the degree of hydrophobization (%).

[0130] The external agent can contain other inorganic oxides in addition to the silica particle. As the other inorganic oxides, for example, strontium titanate, titanium oxide, aluminum oxide, tin oxide, and the like can be listed.

[0131] From the aspect of stability improvement, the particles formed of the silica particles and the inorganic oxide can be subjected to a hydrophobizing treatment on the surface thereof. The inorganic compound can be used alone or in combination of two or more.

[0132] The volume average primary particle diameter D of the toner of the embodiment 50 is 5.5 to 11.0 μm, preferably 5.8 to 10.0 μm, and more preferably 6.0 to 8.0 μm. The volume average primary particle diameter D of the toner 50 is above the lower limit value, and thus the flowability of the toner is improved. Therefore, even in the case of reuse, the poor conveyance of the toner is less likely to occur. The volume average primary particle diameter D of the toner 50 is below the upper limit value, and thus the image density is less likely to decrease.

[0133] A method for producing the toner will be described.

[0134] 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.

[0135] The toner base particles of the embodiment can be produced by, for example, a kneading and pulverizing method, a chemical method.

[0136] The kneading and pulverizing method will be described.

[0137] 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 classification step of the following as necessary.

[0138] • The mixing step: a step of mixing at least the crystalline polyester resin and the ester wax to obtain a mixture.

[0139] • The kneading step: a step of melt-kneading the mixture to obtain a kneaded product.

[0140] • The pulverizing step: a step of pulverizing the kneaded product to obtain a pulverized product.

[0141] • The classification step: a step of classifying the pulverized product.

[0142] 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 necessary.

[0143] 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.

[0144] In the pulverization step, the kneaded material obtained in the kneading step is pulverized to obtain a pulverized material. A pulverizer can be used in the pulverization step. 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.

[0145] In the classification step, the pulverized material obtained in the pulverization step is classified. A classifier can be used in the classification step. The classifier is not particularly limited.

[0146] The chemical method will be described.

[0147] In the chemical method, a crystalline polyester resin, an ester wax, another binder resin 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.

[0148] The method of adding the external additive will be described.

[0149] The external additive is mixed with the toner parent particles by, for example, a mixer. The mixer is not particularly limited.

[0150] 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.

[0151] The toner cartridge of the embodiment will be described.

[0152] 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.

[0153] The toner of the embodiment can be used as a one-component developer, or can be used as a two-component developer in combination with a carrier.

[0154] The image forming apparatus of the embodiment will be described below with reference to the drawings. Figure 1 is a drawing showing an example of a schematic structure of an image forming apparatus that can reuse the recovered toner.

[0155] Figure 1The shown copier main body 101 is provided with: an image forming section 101A provided at a central side portion, a document placing table 135 provided at an upper surface portion, a scanner 136 provided at a lower portion side of the document placing table 135, and multi-stage paper feed cassettes 142, 143 provided at a lower portion side.

[0156] The image forming section 101A has: a photosensitive drum 102 freely rotating in the arrow direction, a charge charger 103 charging the surface of the photosensitive drum 102, a laser unit 104 forming an electrostatic latent image on the surface of the photosensitive drum 102, a developing device 105 developing the electrostatic latent image on the photosensitive drum 102 with toner, a transfer charger 106 transferring the toner image on the photosensitive drum 102 to paper, a cleaning device 107 removing the remaining toner on the photosensitive drum 102, and a replenishment container 108 provided at an upper portion of the developing device 105.

[0157] The charge charger 103, the laser unit 104, the developing device 105, the transfer charger 106, and the cleaning device 107 are provided in this order in the rotation direction of the photosensitive drum 102 around the photosensitive drum 102.

[0158] The replenishment container 108 replenishes the developing device 105 with the toner of the embodiment. The toner of the embodiment is stored in the replenishment container 108.

[0159] The scanner 136 exposes a document on the document placing table 135. The scanner 136 has a light source 137 irradiating light to the document, a first mirror 138 reflecting the light reflected from the document to a predetermined direction, a second mirror 139 and a third mirror 140 sequentially reflecting the light reflected from the first mirror 138, and a light receiving element 141 receiving the light reflected from the third mirror 140.

[0160] The paper feed cassettes 142, 143 feed paper into the image forming section 101A. The paper is fed upward via a conveyance system 144. The conveyance system 144 has a pair of conveyance rollers 145, a pair of registration rollers 146, the transfer charger 106, a pair of fixing rollers 147, and a pair of discharge rollers 148.

[0161] In the image forming apparatus shown, image formation is performed, for example, in the following manner. Figure 1 In the image forming apparatus shown, image formation is performed, for example, in the following manner.

[0162] First, light is irradiated from the light source 137 to the document on the document placing table 135. The irradiated light is reflected from the document, and is sequentially received by the light receiving element 141 via the first mirror 138, the second mirror 139, and the third mirror 140, and the document image is read. Next, based on the information read by the light receiving element 141, laser LB is irradiated from the laser unit 104 to the surface of the photosensitive drum 102.

[0163] Here, the surface of the photosensitive drum 102 is negatively charged by the charging device 103. If laser LB is irradiated from the laser unit 104, the photosensitive drum 102 is exposed, and the potential of the irradiated portion approaches 0. Thus, in the area corresponding to the image portion of the original, the surface potential of the photosensitive drum 102 approaches 0 corresponding to the density of the image, and an electrostatic latent image is formed.

[0164] By rotation of the photosensitive drum 102, the electrostatic latent image is attracted to toner at a position opposite to the developing device 105, and a toner image is formed. In forming the toner image, paper is supplied to the conveyance system 144 from the paper feed cassettes 142, 143. The paper is sent between the transfer charger 106 and the photosensitive drum 102 after the position is adjusted by the registration rollers 146. Thereafter, the toner image on the photosensitive drum 102 is transferred to the paper.

[0165] The paper on which the toner image is transferred is conveyed to the fixing roller pair 147. In the fixing roller pair 147, the paper is pressed and heated, and the toner image is fixed to the paper. The low-temperature fixability of the toner of the embodiment is excellent. Thus, for example, fixing can be performed at around 140 to 170°C. After fixing, the paper is discharged onto the discharge tray 150 via the paper discharge roller pair 148.

[0166] On the other hand, the toner remaining on the surface of the photosensitive drum 102 without being transferred to the paper is removed by the cleaning device 107. Thereafter, the toner is returned to the developing device 105 by the recovery mechanism 110 and is reused. In addition, in the embodiment, the toner is recovered by the recovery mechanism 110 and is reused. Figure 1 In the image forming apparatus shown in the drawing, if the toner in the developing device 105 is consumed, the toner of the embodiment is newly supplied as new toner from the supply container 108.

[0167] The developing device 105 is described with reference to Figure 2 , Figure 3 .

[0168] The developing device 105 has a recovery mechanism 110 that recovers toner in order to reuse the toner, a developing container 111 that houses a developer including the toner of the embodiment, a developing roller 112 that is provided to freely rotate in the developing container 111, a first partition wall 114 and a second partition wall 115 that form a first chamber 116, a second chamber 117, and a third chamber 118 in the developing container 111, a first mixer 120 provided in the first chamber 116, a second mixer 121 provided in the second chamber 117, a third mixer 122 provided in the third chamber 118, a new toner receiving portion 123 that receives new toner supplied from a supply container, a recycled toner receiving portion 124, and a toner density detector 129.

[0169] The developing device 105 is connected to the cleaning device 107 via the recovery mechanism 110. In the developing device 105, the recovery mechanism 110 is a screw auger that conveys the reused toner. However, the recovery mechanism 110 is not limited to the screw auger.

[0170] The cleaning device 107 can be a cleaning blade or a cleaning brush.

[0171] The developing roller 112 is disposed at a position opposite to the lower surface portion of the photosensitive drum. The developing roller 112 supplies the developing agent to the photosensitive drum by rotation.

[0172] The first communication portion 125 is formed at the first end portion side of the first partition wall 114. In addition, the second communication portion 126 is formed at the second end portion side of the first partition wall 114. In addition, the third communication portion 127 and the fourth communication portion 128 are formed at the second partition wall 115, respectively.

[0173] The first chamber 116, the second chamber 117, and the third chamber 118 are partitioned by the first partition wall 114 and the second partition wall 115 in the developing container 111. The first chamber 116, the second chamber 117, and the third chamber 118 are formed substantially in parallel with the axial direction of the photosensitive drum 102.

[0174] Here, the direction in which the first partition wall 114 faces from the second communication portion 126 toward the first communication portion 125 on the paper surface is referred to as the first direction. In addition, the direction opposite to the first direction, that is, the direction in which the first communication portion 125 faces toward the second communication portion 126 is referred to as the second direction.

[0175] The first mixer 120 stirs and conveys the developing agent in the first direction by rotation and supplies the developing agent to the developing roller 112. The second mixer 121 and the third mixer 122 stir and convey the developing agent in the second direction and send the developing agent to the upstream side of the first mixer 120.

[0176] The second mixer 121 and the third mixer 122 are rotationally driven by a drive mechanism. In the developing device 105, the drive mechanism includes a drive motor 162 as a single drive source and a drive gear 163 that rotates by the drive motor 162. The rotation shaft 151 of the third mixer 122 is connected to the drive gear 163 via a large-diameter power transmission gear 164. In addition, the rotation shaft 121a of the second mixer 121 is connected to the large-diameter power transmission gear 164 via a small-diameter power transmission gear 165.

[0177] In the developing device 105 having the above-described configuration, the conveying speed of the developing agent conveyed by the third mixer 122 is lower than the conveying speed of the developing agent conveyed by the second mixer 121. Therefore, the conveying time of the developing agent conveyed by the third mixer 122 is longer than the conveying time of the developing agent conveyed by the second mixer 121.

[0178] In this other embodiment, the second and third mixers 121, 122 can be individually rotationally driven by a plurality of drive motors having different rotational speeds, respectively. In addition, a return blade that returns the recovered toner to the direction opposite to the second direction can be provided in the third mixer 122. Regardless of the method of collection, the recovered toner transported by the third mixer 122 can be made to have a lower transport speed than the developer transported by the second mixer 121.

[0179] Next, the developing operation of the developing device 105 will be described with reference to Figure 2 、 3 to the developing operation of the developing device 105 will be described with reference to

[0180] In the developing container 111, the developer is stirred and transported in the first direction by the rotation of the first mixer 120, and is supplied to the developing roller 112. Thereafter, the developer is supplied to the electrostatic latent image on the photosensitive drum 102 by the rotation of the developing roller 112, and the electrostatic latent image is developed.

[0181] The developer output from the first mixer 120 is guided into the second chamber 117 via the first communication portion 125. Thereafter, in the second chamber 117, the developer is transported in the arrow direction (second direction) by the rotation of the second mixer 121. The developer transported by the second mixer 121 is sent out to the upstream side of the first mixer 120 via the second communication portion 126, and is transported in a manner of circulating between the first mixer 120 and the second mixer 121.

[0182] A part of the developer transported by the second mixer 121 is sent into the third chamber 118 from the third communication portion 127, and is transported in the arrow direction (second direction). The developer is again sent into the second chamber 117 from the fourth communication portion 128, and is stirred and transported by the second mixer 121. Thereafter, the developer is sent into the upstream side of the first mixer 120 via the second communication portion 126.

[0183] Here, the developer stirred and transported by the second mixer 121 is detected for toner concentration by the toner concentration detector 129. If the toner concentration detected by the toner concentration detector 129 is below a predetermined value, the toner of the embodiment is replenished from the replenishment container 108. The toner falls into the new toner receiving portion 123 of the developing container 111. The new toner is stirred and transported in the arrow direction (second direction) by the rotation of the second mixer 121, and is sent into the upstream side of the first mixer 120.

[0184] The recovered toner that is recovered from the cleaning device 107 by the recovery mechanism 110 falls into the recirculation toner receiving portion 124. By rotation of the third mixer 122, the recovered toner is transported to the second direction. Here, the developer that is guided from the third communication portion 127 into the third chamber 118 is temporarily stirred and transported to the recirculation toner receiving portion 124 side by rotation of the return blade 153 of the third mixer 122 as indicated by an arrow a. After that, the developer is stirred and transported to the second direction by rotation of the forward blade 152 as indicated by an arrow b together with the recovered toner. The recovered toner is sequentially sent into the upstream side of the first mixer 120 via the fourth communication portion 128 and the second communication portion 126.

[0185] Among the developer and the recovered toner, there is the developer and the recovered toner that is not sent into the second chamber 117 via the fourth communication portion 128 but is sent to the downstream side of the transport direction. By rotation of the return blade 155, such developer and recovered toner is returned to the fourth communication portion 128 by being returned and is sent into the second chamber 117 via the fourth communication portion 128.

[0186] In the past, in the case where the developer containing toner is reused, an external additive easily falls off from toner parent particles due to physical pressure, and agglomeration is significantly caused. Therefore, there are problems that flowability of the developer is reduced, and the charging amount and the flying amount of the toner are reduced.

[0187] In this regard, the toner of the embodiment is excellent in heat resistance, and thus the flowability of the toner is not easily reduced even in the case where the toner is reused. Therefore, the charging amount and the flying amount of the toner can be sufficiently maintained, and development is favorably performed.

[0188] Figure 4 is an example of an image forming apparatus to which a developer containing the toner of the embodiment is applied.

[0189] Figure 4 The image forming apparatus illustrated is a manner in which a toner image is fixed. However, the image forming apparatus of the embodiment is not limited to this manner. The image forming apparatus to which the other embodiment relates can also be, for example, a manner of an inkjet type.

[0190] Figure 4 The image forming apparatus 1 illustrated is a color copier MFP of a four-in-line tandem manner. The image forming apparatus 1 is provided with a scanner portion 2, a paper discharge portion 3, a paper feed cassette 4, an intermediate transfer belt 10, four image forming positions 1IY, 1IM, 11C, 11K that are arranged along a travel direction S of the intermediate transfer belt 10, a secondary transfer roller 27, a fixing device 30, and a manual paper feed mechanism 31.

[0191] The intermediate transfer belt 10 is wound and supported by a driven roller 20 and a support roller 21. In addition to the driven roller 20 and the support roller 21, an arbitrary tension is applied to the intermediate transfer belt 10 by a first tension roller 22, a second tension roller 23, and a third tension roller 24.

[0192] Each of the image forming positions 11Y, 11M, 11C, and 11K has a photosensitive drum 12Y, 12M, 12C, or 12K in contact with the intermediate transfer belt 10.

[0193] The photosensitive drums 12Y, 12M, 12C, and 12K are provided with a charge roller 13Y, 13M, 13C, or 13K; a developing device 14Y, 14M, 14C, or 14K; a photosensitive cleaner 16Y, 16M, 16C, or 16K; and a primary transfer roller 18Y, 18M, 18C, or 18K.

[0194] The charge rollers 13Y, 13M, 13C, and 13K negatively charge the surfaces of the photosensitive drums 12Y, 12M, 12C, and 12K. Between the charge rollers 13Y, 13M, 13C, and 13K and the developing devices 14Y, 14M, 14C, and 14K, a laser exposure device 17 irradiates exposure light to the photosensitive drums 12Y, 12M, 12C, and 12K. Thereafter, an electrostatic latent image is formed on the photosensitive drums 12Y, 12M, 12C, and 12K.

[0195] The developing devices 14Y, 14M, 14C, and 14K each have a two-component developer formed of each of toners of yellow (Y), magenta (M), cyan (C), and black (K) and a carrier. The developing devices 14Y, 14M, 14C, and 14K each supply the toner to the electrostatic latent image on the photosensitive drums 12Y, 12M, 12C, and 12K. Thus, the image forming positions 11Y, 11M, 11C, and 11K each form a monochromatic image of yellow (Y), magenta (M), cyan (C), or black (K).

[0196] The primary transfer rollers 18Y, 18M, 18C, and 18K are each provided on the intermediate transfer belt 10 at a position opposite to the photosensitive drums 12Y, 12M, 12C, and 12K. The primary transfer rollers 18Y, 18M, 18C, and 18K primary transfer the toner image on the photosensitive drums 12Y, 12M, 12C, and 12K to the intermediate transfer belt 10.

[0197] The primary transfer rollers 18Y, 18M, 18C, and 18K are each a conductive roller. A primary transfer bias voltage is applied to each of the primary transfer rollers 18Y, 18M, 18C, and 18K.

[0198] The secondary transfer roller 27 is provided at a transfer position where the intermediate transfer belt 10 is supported by the support roller 21. The support roller 21 is a conductive roller. A predetermined secondary transfer bias voltage is applied to the support roller 21.

[0199] If the sheet-shaped paper of the print object passes between the intermediate transfer belt 10 and the secondary transfer roller 27, the toner image on the intermediate transfer belt 10 is secondarily transferred onto the sheet-shaped paper. After the secondary transfer is completed, the intermediate transfer belt 10 is cleaned by the belt cleaner 10a.

[0200] The paper cassette 4 is provided below the laser exposure device 17. The paper cassette 4 supplies the sheet-shaped paper Pl to the secondary transfer roller 27. Between the paper cassette 4 and the secondary transfer roller 27, a pickup roller 4a, a separation roller 28a, a conveyance roller 28b, and a registration roller pair 36 are provided.

[0201] The manual paper feed mechanism 31 is provided to a side surface of the image forming apparatus 1. The manual paper feed mechanism 31 feeds the sheet-shaped paper P2 by hand. In the manual paper feed mechanism 31, between a manual tray 31a and the registration roller pair 36, a manual pickup roller 31b and a manual separation roller 31c are provided.

[0202] On a longitudinal conveyance path 35 through which the sheet-shaped paper is conveyed from the paper cassette 4 or the manual tray 31a, a medium sensor 39 that detects the kind of the sheet-shaped paper is provided. The image forming apparatus 1 can control the conveyance speed of the sheet-shaped paper, the transfer condition, the fixing condition, and the like, based on the detection result of the medium sensor 39. The sheet-shaped paper is conveyed along the longitudinal conveyance path 35, passes through the registration roller pair 36 and the secondary transfer roller 27, and is conveyed to the fixing device 30.

[0203] The fixing device 30 has a fixing belt 53 wound around a pair of a heating roller 51 and a driving roller 52, and an opposing roller 54 provided opposite to the heating roller 51 via the fixing belt 53. The fixing device 30 can heat the fixing belt 53 at a portion in contact with the heating roller 51. Then, the fixing device 30 heats and presses the sheet-shaped paper on which the toner image is transferred between the fixing belt 53 and the opposing roller 54, and fixes the toner image to the sheet-shaped paper.

[0204] The low-temperature fixability of the toner of the embodiment is excellent. Therefore, for example, fixing can be performed at around 140 to 170°C.

[0205] A door 33 is provided downstream of the fixing device 30. The sheet-shaped paper is distributed to a paper discharge roller 41 direction or a repeat conveyance unit 32 direction. The sheet-shaped paper distributed to the paper discharge roller 41 is discharged from the paper discharge portion 3. On the other hand, the sheet-shaped paper distributed to the repeat conveyance unit 32 is guided to the secondary transfer roller 27 again.

[0206] In Figure 4In the illustrated image forming apparatus 1, the image forming position 11Y has an integral photosensitive drum 12Y and processing components, and is freely detachably provided to the image forming apparatus main body. As the processing components, a charging device 13Y, a developing device 14Y, and a photosensitive body cleaning device 16Y can be cited. Among them, in other embodiments, each of the image forming positions 11Y, 11M, 11C, and 11K can be freely detachable with respect to the image forming apparatus, respectively, or can be freely detachable with respect to the image forming apparatus as an integral image forming unit 11.

[0207] The toner of the embodiments can also be applied to Figure 4 the illustrated image forming apparatus. Figure 5 is an example of a modification of the developing device of the image forming apparatus that can be applied to Figure 4 .

[0208] Figure 5 The developing device 64Y illustrated in the drawing accommodates a two-component developer formed of yellow toner and a carrier. The developing device 64Y has a toner concentration sensor Q. The toner concentration sensor Q detects a decrease in the concentration of the toner. If the developing device 64Y detects a decrease in the concentration, yellow toner is replenished from a toner cartridge (not illustrated). In this way, the developing device 64Y can maintain the toner concentration constant.

[0209] In addition, the developing device 64Y can replenish the carrier from a toner cartridge (not illustrated) via a developer replenishing port 64Y1. Then, the developing device 64Y can discharge the developer from a developer discharge port 64Y2 only by the replenished portion by way of overflow.

[0210] In this way, in the developing device 64Y, the amount of the developer can be maintained constant, and the old deteriorated carrier is gradually replaced with a new carrier.

[0211] Figure 4 The developing devices 14M, 14C, and 14K of the illustrated image forming apparatus can be modified to the same developing devices 64M, 64C, and 64K (not illustrated) as the developing device 64Y, respectively, except that magenta toner, cyan toner, and black toner are used instead of yellow toner, respectively.

[0212] The toner of at least one of the embodiments described above is excellent in low-temperature fixing property, excellent in heat resistance even in the case of being reused, can sufficiently maintain a charge amount, and difficult to decrease in image density.

[0213] Example

[0214] Hereinafter, an example will be shown to more specifically describe the embodiments.

[0215] The preparation of the ester waxes A to Q and the ester waxes a to i of the Examples will be described.

[0216] Into a four-necked flask equipped with a stirrer, a thermocouple, and a nitrogen inlet tube, at least three or more long-chain alkyl carboxylic acids 80 parts by mass and at least three or more long-chain alkyl alcohols 20 parts by mass were charged. An esterification reaction was carried out under a stream of nitrogen at 220°C to obtain a reaction product. The obtained reaction product was added to a mixed solution of toluene and ethanol 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, 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 in the flask were allowed to stand for 30 minutes, 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 the ester wax A.

[0217] The kinds and amounts of use of the long-chain alkyl carboxylic acids and the long-chain alkyl alcohols were changed, and the ester waxes B to Q were obtained in the same manner as the ester wax A. Further, the ester waxes a to i were obtained by the same operation.

[0218] The long-chain alkyl carboxylic acids used were as follows.

[0219]

[0220] The long-chain alkyl alcohols used were as follows.

[0221]

[0222]

[0223] The toner of Example 1 was produced as follows.

[0224] First, the raw materials of the toner base particles were added to a Henshel mixer (manufactured by Mitsui Mining Co., Ltd.) and mixed. The mixture of the raw materials of the toner base particles was melt-kneaded using a twin-screw extruder. After cooling the melt-kneaded product, 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 base particles.

[0225] The composition of the raw materials of the toner base particles is shown below.

[0226]

[0227] 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 base particles of Example 1 using a Henshel mixer.

[0228]

[0229] The toners of Examples 2 to 18 and Comparative Examples 1 to 24 were produced as follows.

[0230] First, regarding the composition of the raw material of the toner base particles, the ester wax shown in each column of Tables 1 to 3 was used instead of the ester wax A, and otherwise, the toner base particles of Examples 2 to 18 and Comparative Examples 1 to 24 were produced in the same manner as in Example 1.

[0231] Next, regarding the silica particles A, the silica particles B, and the silica particles C, the particle diameter r A , the particle diameter r B , the particle diameter r C , the content w A , the content w B , the content w C , and otherwise, the toner base particles of each example were mixed with the external additive in the same manner as in Example 1, thereby producing the toners of Examples 2 to 18 and Comparative Examples 1 to 24.

[0232] [Table 1]

[0233]

[0234] [Table 2]

[0235]

[0236] [Table 3]

[0237]

[0238] The measurement method of the carbon number distribution (the proportion of the ester compound of each carbon number) of the ester compound constituting the ester wax was described.

[0239] 0.5 g of the toner of each example was weighed and accommodated in a triangular flask. Next, 2 mL of dichloromethane was added to the triangular flask to dissolve the toner. 4 mL of hexane was further added to the triangular flask, thereby preparing 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 with respect to the precipitate.

[0240] The proportion of the ester compound of each carbon number was measured by FD-MS "JMS-T100GC (manufactured by JEOL Ltd.)". The measurement conditions were as follows.

[0241] Sample concentration: 1 mg / ml (solvent: chloroform).

[0242] Cathode voltage: -10 kv.

[0243] Spectrum recording interval: 0.4 s.

[0244] Measurement mass range (m / z): 10 to 2000.

[0245] The total of the ion intensities of the ester compounds of each carbon number measured was taken as 100. The relative values of the ion intensities of the ester compounds of each carbon number with respect to the total were calculated. The relative values were taken as the proportions of the ester compounds of each carbon number in the ester wax. In addition, the carbon number of the ester compound of which the relative value was the largest was taken as C l .

[0246] The analysis method of the first monomer group and the second monomer group will be described.

[0247] Each ester wax 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 using FD-MS, and the content of long-chain alkyl carboxylic acid of each carbon number and the content of long-chain alkyl alcohol of each carbon number were calculated.

[0248] The method of measuring the carbon number distribution of the carboxylic acids (proportion of carboxylic acid of each carbon number) constituting the first monomer group will be described.

[0249] The proportion of carboxylic acid of each carbon number was measured by FD-MS "JMS-T100GC (manufactured by JEOL Ltd.)". The measurement conditions were as follows.

[0250] Sample concentration: 1 mg / ml (solvent: chloroform).

[0251] Cathode voltage: -10 kv.

[0252] Spectrum recording interval: 0.4 s.

[0253] Measurement mass range (m / z): 10 to 2000.

[0254] 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 calculated. 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 of which the relative value was the largest was taken as C n .

[0255] The method of measuring the carbon number distribution of the alcohols (proportion of alcohol of each carbon number) constituting the second monomer group will be described.

[0256] The proportion of alcohol of each carbon number was measured by FD-MS "JMS-T100GC (manufactured by JEOL Ltd.)". The measurement conditions were as follows.

[0257] Sample concentration: 1 mg / ml (solvent: chloroform)

[0258] Cathode voltage: -10 kv.

[0259] Spectrum recording interval: 0.4 s.

[0260] Measurement mass range (m / z): 10 to 2000.

[0261] The total of the ion intensities of the alcohols of each carbon number measured was set to 100. The relative values of the ion intensities of the alcohols of each carbon number to the total were obtained. 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 .

[0262] The ester waxes A to Q used in each example were described.

[0263] In any of the ester waxes A to Q, the carbon number C l of the ester compound in which the content was the largest in the first monomer group was 44, the carbon number C n of the alcohol in which the content was the largest in the second monomer group was 22, and the carbon number C m of the alcohol in which the content was the largest was 20.

[0264] In the ester waxes A to Q, the carbon number distribution of the ester wax had only one maximum peak in the region of the carbon number of 43 or more.

[0265] The properties of the ester waxes A to Q obtained from the measurement results of the mass distribution are shown in Table 4. In addition, the properties of the ester waxes a to i are shown in Table 5.

[0266] [Table 4]

[0267] [Table 4]

[0268] [a1] [a2] [ b1 ] [ b2 ] ​ [ca2] Ester Wax A 4 3 3 15 82.5 80 Ester Wax B 3 3 2 15 95 70 Ester Wax C 3 3 0 5 90 90 Ester Wax D 3 4 0 5 90 90 Ester Wax E 3 3 5 18 85 82 Ester Wax F 4 3 3 15 70 70 Ester Wax G 4 3 3 15 70 70 Ester Wax H 4 3 3 15 70 70 Ester Wax I 4 3 3 15 70 70 Ester Wax J 4 3 3 15 82.5 80 Ester Wax K 4 3 3 15 82.5 80 Ester Wax L 4 3 3 15 82.5 80 Ester Wax M 4 3 3 15 82.5 80 Ester Wax N 4 3 3 15 82.5 80 Ester Wax O 4 3 3 15 82.5 80 Ester Wax P 4 3 3 15 82.5 80 Ester Wax Q 4 3 3 15 82.5 80

[0269] [Table 5]

[0270] [Table 5]

[0271] [a1] [a2] [ b1 ] [ b2 ] ​ [c2] Ester Wax a 5 3 1 38 65 55 Ester Wax b 3 4 5 38 70 60 Ester Wax c 3 3 10 15 60 60 Ester Wax d 3 3 10 40 85 50 Ester Wax e 4 5 10 40 80 50 Ester Wax f 2 3 5 15 95 85 Ester Wax g 3 2 3 5 90 95 Ester Wax h 3 2 3 5 90 95 Ester Wax i 1 1 100 100 100 100

[0272] In Tables 4 and 5, a1 is the number [pieces] of the types of the carboxylic acids in the first monomer group. a2 is the number [pieces] of the types of the alcohols in the second monomer group. b1 is the total proportion [mass %] of the carboxylic acids of the carbon number of 18 or less with respect to 100 mass % of the first monomer group. b2 is the total proportion [mass %] of the alcohols of the carbon number of 18 or less with respect to 100 mass % of the second monomer group. c1 is the proportion [mass %] of the carboxylic acid of the carbon number C n with respect to 100 mass % of the first monomer group. c2 is the carbon number of the alcohol in which the carbon number was the largest.m The ratio of alcohol to 100% by mass of the second monomer group [mass %].

[0273] The volume-average primary particle size D of the toner in each example 50 The determination method is explained.

[0274] A laser diffraction particle size distribution measuring device (manufactured by Shimadzu Corporation (SALD7000)) was used.

[0275] The developer used in the examples will be described.

[0276] The developer for each example was obtained by stirring 8.5 parts by mass of the toner into 100 parts by mass of the ferrite carrier using a rotary mixer. The surface of the ferrite carrier was coated with silicone resin with an average particle size of 40 μm.

[0277] The evaluation method for low-temperature fixing is explained.

[0278] The developer for each example was stored in a toner cartridge. This toner cartridge was then placed within an image forming apparatus used for evaluating low-temperature fixing properties. The image forming apparatus for evaluating low-temperature fixing properties was a modified commercially available e-studio5018A (manufactured by TOSHIBA TEC) that allowed the fixing temperature to be changed and set in 0.1°C increments within a range of 100°C to 200°C. Using this image forming apparatus for evaluating low-temperature fixing properties, with the fixing temperature set to 150°C, 10 images were obtained showing a toner adhesion of 1.5 mg / cm². 2 Solid images were obtained. If no image peeling due to offset or unfixed conditions occurred in any of the 10 solid images, the temperature was lowered by 1°C, and the same operation was performed to obtain solid images. This operation was repeated to determine the lower limit of the fixing temperature at which image peeling would not occur on the solid images, and this lower limit was taken as the minimum fixing temperature of the toner. When the minimum fixing temperature is below 120°C, the low-temperature fixing performance of the toner is evaluated as acceptable (○). When the minimum fixing temperature exceeds 120°C, the low-temperature fixing performance of the toner is evaluated as unacceptable (×).

[0279] The evaluation method for preservation is explained.

[0280] Each sample of toner was placed at 55°C for 10 hours. After 10 hours at 55°C, 15g of each sample of toner was sieved through a 0.07mm sieve, and the amount of toner remaining on the sieve was weighed. The less toner remaining on the sieve, the better the shelf life. If less than 3g of toner remained on the sieve, the shelf life of the toner was rated as acceptable (○). If more than 3g of toner remained on the sieve, the shelf life of the toner was rated as unacceptable (×).

[0281] The evaluation method for heat resistance is described.

[0282] In the case where the evaluation results of "flowability" and "amount of scattering" described below are both acceptable (O), the heat resistance is evaluated as excellent.

[0283] The evaluation method for "flowability" is described.

[0284] The developer of each example was housed in a toner cartridge. The toner cartridge was disposed in an image forming apparatus used for evaluating heat resistance. The image forming apparatus used for evaluating heat resistance was a device obtained by installing a thermocouple in the developer of a commercially available e-studio 5018A (manufactured by TOSHIBA TEC). Using the image forming apparatus used for evaluating heat resistance, a solid image and a half-tone image were continuously copied 1000 times on A4 paper in a high-temperature and high-humidity environment (30°C, humidity 85%). While copying, it was confirmed whether or not a defective image appeared when the temperature in the developer increased every 2°C, and the temperature at which a defective image began to appear was recorded. When the temperature at which a defective image began to appear was 47°C or higher, the flowability of the toner was evaluated as acceptable (O). When the temperature at which defective conveyance and a defective image began to appear was lower than 45°C, the flowability of the toner was evaluated as unacceptable (X).

[0285] The evaluation method for "amount of scattering" is described.

[0286] Using a commercially available e-studio 5018A (manufactured by TOSHIBA TEC), a document with a print rate of 8.0% was continuously copied 200,000 times on A4 paper. Thereafter, the toner accumulated on the lower side of the magnetic roller of the developer was suctioned using a dust collector, and the accumulated toner was measured as the amount of scattered toner. When the amount of scattered toner was 170 mg or less, the charge amount (amount of scattering) of the toner was evaluated as acceptable (O). When the amount of scattered toner exceeded 170 mg, the charge amount (amount of scattering) of the toner was evaluated as unacceptable (X).

[0287] The evaluation method for image density is described.

[0288] The developer of each example was housed in a toner cartridge. The toner cartridge was disposed in a commercially available e-studio 5018A (manufactured by TOSHIBA TEC). The concentration of the toner in the developer was adjusted to 8.0% in a low-temperature and low-humidity environment (10°C, humidity 20%), and a solid image was printed on A4 paper. The density of the obtained solid image was measured using a Macbeth densitometer, and when the density was 1.0 or higher, the image density was evaluated as acceptable (O). When the density was lower than 1.0, the image density was evaluated as unacceptable (X).

[0289] The evaluation results of the low-temperature fixing properties, preservation properties, flowability, scattering, and image density of the toners in each example are shown in Tables 1-3. In Tables 1-3, "D" 50 "This is the volume average primary particle size D of the toner in each example." 50 [μm].

[0290] The toners of Examples 1-18 exhibit excellent low-temperature fixing properties and heat resistance, without a decrease in image density. Furthermore, the toners have low contamination levels, effectively maintaining the charge within the image forming apparatus. The e-studio5018A is an image forming apparatus that reuses toners. Therefore, even when reused, the toners of Examples 1-18 maintain excellent heat resistance, effectively retain their charge, and are unlikely to experience a decrease in image density.

[0291] In addition, the toners of Examples 1 to 17 also exhibit excellent preservation properties.

[0292] In contrast, the low-temperature fixing performance, heat resistance, and image density of Comparative Examples 1 to 24 did not simultaneously meet the qualification standards.

[0293] While several embodiments have been described, these embodiments are merely illustrative and not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and likewise within the scope of the invention as described in the claims and its equivalents.

Claims

1. A toner, characterized in that, It contains toner master particles and additives attached to the surface of the toner master particles. The colorant masterbatch contains crystalline polyester resin and ester wax. The ester wax is a condensation polymer of a first monomer group and a second monomer group, wherein the first monomer group contains at least three carboxylic acids and the second monomer group contains at least three alcohols. The highest number of carbon atoms in the first monomer group is C. n The proportion of carboxylic acid relative to 100% by mass of the first monomer group is 70-95% by mass. The proportion of carboxylic acids with 18 or fewer carbon atoms in the first monomer group is less than 5% by mass relative to 100% by mass of the first monomer group. The highest number of carbon atoms in the second monomer group is C. m The proportion of alcohol relative to 100% by mass of the second monomer group is 70-90% by mass. The proportion of alcohols with 18 or fewer carbon atoms in the second monomer group is less than 20% by mass relative to 100% by mass of the second monomer group. The additive contains silica particles A, silica particles B, and silica particles C, wherein the particle size r of silica particles A is... A The particle size r of the silicon dioxide particles B is 10-14 nm. B The particle size r of the silica particles C is 40–70 nm. C The wavelength is 90–150 nm. The content of the silica particles A is 0.1 to 0.8 parts by weight relative to 100 parts by weight of the toner master particles. The content of silica particles B is 0.3 to 1.2 parts by mass relative to 100 parts by mass of the toner master particles. The content of the silica particles C is 0.3 to 1.2 parts by mass relative to 100 parts by mass of the colorant master particles. The total content of silica particles A, silica particles B, and silica particles C is less than 3.0 parts by weight relative to 100 parts by weight of the toner masterbatch. The ratio of the content of silica particles B to the content of silica particles A is 1.0 to 5.

0. The ratio of the content of silica particles C to the content of silica particles A is 1.0 to 5.

0. The volume average primary particle size D of the toner 50 The range is 5.5–11.0 μm.

2. The toner according to claim 1, characterized in that, In the particle size distribution measured on the additive, there are at least three maximum peaks of silica particles, with at least one maximum peak in each of the ranges of 10–14 nm, 40–70 nm, and 90–150 nm.

3. The toner according to claim 1 or 2, characterized in that, The total content of silica particles A, silica particles B, and silica particles C is at least 1.0 part by mass relative to 100 parts by mass of the toner masterbatch.

4. A toner box, characterized in that, The container contains the toner according to any one of claims 1 to 3.

5. An image forming apparatus, characterized in that, The container contains the toner according to any one of claims 1 to 3.

Images