JP7731774B2 - toner - Google Patents

Description

The present invention relates to toner used in electrophotography, electrostatic recording, electrostatic printing, and toner jet printing.

2. Description of the Related Art In recent years, as electrophotographic full-color copying machines have become widespread, there has been a demand for even higher speeds, higher image quality, and higher productivity.
In order to achieve high image quality, it is important to improve the pigment dispersibility in toner particles and maximize the coloring power of the pigment. However, pigments generally used in toners have primary particles of several nanometers to several tens of nanometers in size, and the primary particles tend to have strong cohesion forces, which makes them prone to insufficient dispersion in a medium such as a molten resin.
As a means for improving the dispersibility of pigments in toner particles, a pigment dispersant may be added. Patent Document 1 describes an example in which a salicylic acid-based resin is used as a pigment dispersant.
However, in order to meet the recent demand for high image quality, the coloring power of pigments has not been maximized, and there is still room for improvement.

JP 2013-68947 A

The object of the present invention is to provide a toner that solves the above problems. Specifically, the object is to provide a toner that has excellent coloring power, high-temperature offset resistance, and charging stability.

As a result of extensive research, the present inventors have found that by using the constitution of the present invention, it is possible to provide a toner having excellent coloring power, high-temperature offset resistance, and charge stability.
The toner of the present invention is a toner having toner particles containing a binder resin, a colorant, and a resin composition,
The resin composition contains a polyolefin unit and a unit represented by the following formula (1):
The toner is characterized in that the colorant is an organic pigment.

(n represents 3≦n≦10. R1 and R2 each independently represent H or _CH3 .)

The present invention makes it possible to provide a toner with excellent coloring power, high-temperature offset resistance, and charging stability.

In the present invention, unless otherwise specified, the expressions "xx or more and xx or less" and "xx to xx" indicating a numerical range mean a numerical range including the endpoints, that is, the lower and upper limits.

The inventors conducted extensive research with the aim of further improving excellent coloring power, hot offset resistance, and charge stability, and discovered that by using a resin composition containing a unit represented by the following general formula (1) and a toner containing toner particles containing an organic pigment as a colorant, it is possible to achieve unprecedentedly excellent coloring power, high-temperature offset resistance, and charge stability.

(n represents 3≦n≦10. R1 and R2 each independently represent H or _CH3 .)

The authors believe the reasons for the effects of this invention are as follows:

In order to improve the coloring power of toner, it is necessary to maximize the coloring power of the pigment in the toner particles. The reason for the decline in the coloring power of the pigment in toner particles is thought to be that the primary particles that make up the pigment, which are several nanometers to several tens of nanometers in size, have strong cohesive forces, resulting in insufficient dispersion of the primary pigment particles within the toner particles.

The molecular structure of pigments is thought to be a factor in why primary pigment particles have strong cohesive forces. Many organic pigments commonly used in toners have a structure in which a nitrogen atom is bonded to an aromatic ring. This structure in which a nitrogen atom is bonded to an aromatic ring changes the light absorption wavelength of pigments, and by having an absorption range in the visible light wavelength range, pigments can exhibit a variety of coloring power. On the other hand, when a nitrogen atom is bonded to an aromatic ring, the nitrogen atom's lone electron pair forms a resonance structure with the aromatic ring, which is thought to cause polarization within the molecule. This polarization within the molecule generates electrostatic attraction between the polarized particles. As a result, it is thought that the electrostatic attraction generated by the intramolecular polarization on the surface of the primary particles generates strong cohesive forces between the primary pigment particles.

As a result of extensive research, the inventors have discovered that by using a resin composition containing a unit represented by the above general formula (1) and a toner containing toner particles containing an organic pigment as a colorant, it is possible to obtain a toner with superior coloring power not previously available.

The unit represented by the above general formula (1) is a unit containing multiple ether bonds. The ether bond is composed of a carbon atom and an oxygen atom. Because carbon atoms and oxygen atoms have different electronegativities, weak polarization occurs within the ether bond. In other words, it is believed that the polarization on the surface of the primary particles of the organic pigment and the polarization within the ether bond in the above general formula (1) interact with each other, selectively stabilizing the resin composition around the primary particles of the pigment. As a result, it is believed that the resin composition enters between the primary particles of the pigment, suppressing the electrostatic attraction between the primary particles of the pigment, thereby achieving the effect of dispersing the primary particles of the pigment.

The resin composition is further characterized by containing polyolefin units. Polyolefin units are materials with little electrical bias and are thought to have relatively weak intermolecular interactions. When the resin composition is stabilized around primary pigment particles, the units of the resin composition represented by general formula (1) above are thought to be biased toward the pigment due to differences in polarization, and the polyolefin units are thought to be biased toward the outside of the resin composition surrounding the pigment. Because the polyolefin units have weak intermolecular interactions, they are thought to function to stabilize the dispersion state of the primary pigment particles (suppress re-aggregation).

Based on the above, we believe that when this resin composition is combined with an organic pigment as a colorant, the dispersion stability of the pigment primary particles is improved, resulting in improved coloring power of the toner.

<Resin composition>
The resin composition used in the toner of the present invention will be described.

The resin composition used in the toner of the present invention is characterized by containing a polyolefin unit and a unit represented by the following formula (1):

(n represents 3≦n≦10. R1 and R2 each independently represent H or _CH3 .)

The polyolefin unit and the unit represented by formula (1) are chemically bonded molecules, and preferably form a graft polymer with the polyolefin unit as the backbone and the unit of formula (1) as the branch. By using a graft polymer, the radius of gyration of the resin composition is reduced, which suppresses aggregation of primary particles that occurs when one molecule of the resin composition bridges between multiple primary pigment particles, improving the dispersion stability of the pigment primary particles and enhancing the coloring power of the toner.

The method for obtaining the graft polymer is not particularly limited, and any conventionally known method can be used.

The unit represented by formula (1) contains ethylene glycol with n being 3 or more and 10 or less, which interacts with the primary particles of the pigment, resulting in improved pigment dispersibility.

Examples of units represented by formula (1) where n is 3 or more and 10 or less include units derived from the following monomers:

Examples include polyethylene glycol methacrylates (n = 3 to 10), polyethylene glycol acrylates (n = 3 to 10), methoxypolyethylene glycol methacrylates (n = 3 to 10), and methoxypolyethylene glycol acrylates (n = 3 to 10).

In formula (1), n is preferably 5 or more and 8 or less, and by keeping it within this range, the dispersibility of the pigment will be better.

The content of the unit represented by formula (1) in the resin composition is preferably 4% by mass or more and 19% by mass or less, and more preferably 7% by mass or more and 13% by mass or less. By keeping the content within this range, the unit interacts with the pigment and facilitates stabilizing dispersion, improving the coloring power of the toner. Furthermore, the dispersibility of the release agent in the toner particles is improved, thereby improving hot offset resistance.

The polyolefin unit is preferably contained in the resin composition in an amount of 10% by mass or more and 30% by mass or less, and more preferably 10% by mass or more and 20% by mass or less. By containing the polyolefin unit in this range, the polyolefin unit interacts with the pigment and facilitates stabilizing dispersion, thereby improving the coloring power of the toner. Furthermore, the dispersibility of the release agent in the toner particles is improved, thereby improving hot offset resistance.

The weight-average molecular weight of the polyolefin unit is preferably 0.9×10 ⁴ or more and 7.0×10 ⁴ or less, and more preferably 3.0×10 ⁴ or more and 6.0×10 ⁴ or less. When the weight-average molecular weight is within the above range, the polyolefin unit interacts with the pigment and facilitates stabilizing dispersion, thereby improving the coloring power of the toner. Furthermore, the dispersibility of the release agent in the toner particles is improved, thereby improving hot offset resistance.

The polyolefin unit is preferably at least one selected from the group consisting of hydrocarbon waxes such as polyethylene, polypropylene, and alkylene copolymers. Of these, polyethylene and polypropylene are preferred, with polypropylene being more preferred from the perspective of charge retention because it suppresses the molecular mobility of the hydrocarbon unit.

In order to stabilize the dispersion of primary pigment particles in toner particles, it is important to balance the content of the unit represented by formula (1) and the olefin unit. This balance can be evaluated by infrared absorption spectroscopy (FT-IR spectroscopy). In the FT-IR spectroscopy, when the maximum absorption peak intensity in the range of 2800 cm ^-1 to 2900 cm ^-1 is defined as P1 and the maximum absorption peak intensity in the range of 1050 cm ^-1 to 1150 cm ^-1 is defined as P2, the ratio of P1 to P2 (P2/P1) is preferably in the range of 1.3 to 3.0, and more preferably in the range of 1.4 to 2.5 (details of the measurement method will be described later).

The resin composition may be a copolymer containing the unit represented by formula (1) and the styrene unit together with other monomers.

The resin composition preferably contains 50% by mass or more of the styrene unit, and more preferably 60% by mass or more. By keeping the content within this range, the molecular mobility of the resin composition containing the styrene-acrylic unit is suppressed, improving the charge retention.

Monomers that form styrene units include styrene-based monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, p-methoxystyrene, p-hydroxystyrene, p-acetoxystyrene, vinyltoluene, ethylstyrene, phenylstyrene, and benzylstyrene.

Other monomers include vinyl ester monomers such as vinyl acetate; vinyl ether monomers such as vinyl methyl ether; halogen-containing vinyl monomers such as vinyl chloride; diene monomers such as butadiene and isobutylene; cycloalkyl group-containing vinyl monomers such as cyclohexyl acrylate; acid value-adding monomers such as acrylic acid, methacrylic acid, maleic anhydride, and maleic acid half ester, and combinations of these.

The weight average molecular weight of the resin composition is preferably 1.5 × 10 ⁴ or more and 5.0 × 10 ⁵ or less, and more preferably 1.5 × 10 ⁴ or more and 5.0 × 10 ⁴ or less. When the weight average molecular weight is within the above range, the dispersibility in the polyester resin is improved and the interaction with the pigment is facilitated, thereby improving the coloring power of the toner.

The content of the resin composition is preferably 3 to 20 parts by weight, and more preferably 5 to 15 parts by weight, per 100 parts by weight of the binder resin. When the content of the resin composition is within the above range, it is well dispersed in the polyester resin and interacts easily with the pigment, improving the coloring power of the toner.

<Binder resin>
The binder resin used in the toner of the present invention will be described.

The toner of the present invention preferably contains 30% by mass or more of amorphous polyester as a binder resin, more preferably 50% by mass or more, and particularly preferably 70% by mass or more. By keeping the amorphous polyester content within the above range, it becomes easier to control pigment dispersibility from the standpoint of affinity with the binder resin, pigment, and resin composition, and the coloring power of the toner is improved.

In the present invention, the binder resin may be used in combination with other resins as long as the amorphous polyester is within the above range.

Other resins that can be used include known binder resins. For example, the following binder resins can be used:

Styrene-based resins, styrene-based copolymer resins, polyol resins, polyvinyl chloride resins, phenolic resins, natural resin-modified phenolic resins, natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone-indene resins, and petroleum-based resins. Preferred resins include styrene-based copolymer resins, polyester resins, and hybrid resins in which polyester resins and styrene-based copolymer resins are mixed or partially reacted.

The toner particles of the present invention may also contain a crystalline polyester resin. Any known crystalline polyester resin can be used. "Crystalline" refers to a resin that exhibits a clear melting point in differential scanning calorimetry analysis.

The components that make up the amorphous polyester are described in detail below. Note that one or more of the following components can be used depending on the type and application.

The divalent acid component that constitutes the amorphous polyester includes the following dicarboxylic acids or their derivatives:

Benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or their anhydrides or lower alkyl esters; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or their anhydrides or lower alkyl esters; alkenylsuccinic acids or alkylsuccinic acids having an average carbon number of 1 to 50, or their anhydrides or lower alkyl esters; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or their anhydrides or lower alkyl esters. Examples of alkyl groups in the lower alkyl esters include methyl, ethyl, propyl, and isopropyl groups.

On the other hand, examples of dihydric alcohol components that make up amorphous polyester include the following:

Ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated bisphenol A, bisphenols represented by formula (I-1) and their derivatives, and diols represented by formula (I-2).

(In formula (I-1), R represents an ethylene group or a propylene group, x and y each represent an integer of 0 or more, and the average value of x+y is 0 or more and 10 or less.)

(In formula (I-2), R' is an ethylene group or a propylene group, x' and y' are each an integer of 0 or more, and the average value of x' + y' is 0 or more and 10 or less.)

The constituent components of the amorphous polyester may contain, in addition to the divalent carboxylic acid compounds and divalent alcohol compounds described above, trivalent or higher carboxylic acid compounds and trivalent or higher alcohol compounds as constituent components.

Trivalent or higher carboxylic acid compounds are not particularly limited, but examples include trimellitic acid, trimellitic anhydride, and pyromellitic acid. Furthermore, trivalent or higher alcohol compounds include trimethylolpropane, pentaerythritol, and glycerin.

In addition to the compounds mentioned above, the constituent components of the amorphous polyester may also contain monocarboxylic acid compounds and monohydric alcohol compounds as constituent components. Specific examples of monocarboxylic acid compounds include palmitic acid, stearic acid, arachidic acid, and behenic acid. Other examples include cerotic acid, heptacosanoic acid, montanic acid, melissic acid, lacteric acid, tetracontanoic acid, and pentacontanoic acid.

Examples of monohydric alcohol compounds include behenyl alcohol, ceryl alcohol, melissyl alcohol, and tetracontanol.

The method for producing the amorphous polyester is not particularly limited, and any known method can be used.

For example, the aforementioned dicarboxylic acid compound and dialcohol compound can be polymerized via an esterification reaction or transesterification reaction and a condensation reaction to produce an amorphous polyester.

The polymerization temperature is not particularly limited, but is preferably in the range of 180°C or higher and 290°C or lower.

When polymerizing amorphous polyesters, polymerization catalysts such as titanium-based catalysts, tin-based catalysts, zinc acetate, antimony trioxide, and germanium dioxide can be used.

The softening point (hereinafter simply referred to as Tm) of the binder resin in the present invention is preferably 85°C or higher and 155°C or lower, and more preferably 100°C or higher and 155°C or lower.

When the softening point of the binder resin is within the above range, high-temperature offset resistance is improved.

Furthermore, the glass transition temperature (Tg) of the binder resin is preferably 50°C or higher and 65°C or lower, and more preferably 55°C or higher and 60°C or lower.

By ensuring that the glass transition temperature (Tg) of the binder resin is within the above range, molecular mobility is suppressed in high-temperature, high-humidity environments, resulting in good toner charge retention.

<Coloring Agent>
The colorant usable in the present invention is characterized by being an organic pigment, which facilitates interaction between the intramolecular polarization of the colorant and the resin composition, thereby improving pigment dispersibility.

The colorant can be one or more known organic pigments. Examples of organic pigments include yellow pigments (C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 23, 62, 65, 73, 74, 81, 83, 93, 94, 95, 97, 98, 109, 110, 111, 117, 120, 127, 128, 129, 137, 138, 139, 147, 151, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 55, 167, 168, 173, 174, 176, 180, 181, 183, 191, C.I. Vat Yellow 1, 3, 20), cyan pigments (C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66, etc., C.I. Vat Blue 6, C.I. Acid Blue 45), magenta pigments (C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66, etc., C.I. Vat Blue 6, C.I. Acid Blue 45), Segment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57, 57:1, 58, 60, 63, 64, 68, 81, 81:1, Examples of organic pigments include C.I. Pigment Violet 19 (C.I. Bat Red 1, 2, 10, 13, 15, 23, 29, 35), C.I. Pigment Blue 15:3, C.I. Pigment Red 122, and C.I. Pigment Red 150. These organic pigments are also suitable for use in toners with improved pigment dispersibility. C.I. Pigment Blue 15:3, C.I. Pigment Red 122, and C.I. Pigment Red 150 are more preferred for improved pigment dispersibility.

The toner of the present invention can be used in combination with known inorganic pigments and dyes other than the above organic pigments.

Inorganic pigments and dyes that can be used in combination include carbon blacks such as furnace black, channel black, acetylene black, thermal black, and lamp black, as well as magnetic powders such as magnetite and ferrite, yellow dyes (C.I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, etc.), cyan dyes (C.I. Solvent Blue 25, 36, 60, 70, 93, 95, etc.), and magenta dyes (C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 50, etc.). 2, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, 122, etc., C.I. Disperse Red 9, C.I. Solvent Violet 8, 13, 14, 21, 27, etc., C.I. Disperse Violet 1, etc., and basic dyes such as C.I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, etc., C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28, etc.).

The content of the colorant is preferably 1 part by weight or more and 20 parts by weight or less per 100 parts by weight of the binder resin. More preferably, it is 4 parts by weight or more and 15 parts by weight or less per 100 parts by weight of the binder resin.

Furthermore, the ratio (X2/X1) of the parts by mass of the pigment (X2) to the parts by mass of the resin composition (X1) is preferably 0.2 or more and 3.0 or less, and more preferably 0.5 or more and 2.0 or less. By keeping it within this range, pigment dispersibility and hot offset resistance are improved.

<Release Agent>
The toner of the present invention may contain a release agent (wax) to impart releasability to the toner.

Examples of waxes that can be used in the present invention include: aliphatic hydrocarbon waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, olefin copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxidized aliphatic hydrocarbon waxes such as oxidized polyethylene wax; waxes whose main component is a fatty acid ester such as carnauba wax, behenyl behenate, and montan acid ester wax; and partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax. Further, saturated straight-chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassidic acid, eleostearic acid, and valinaric acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; saturated fatty acid bisamides such as methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, and hexamethylene bisstearic acid amide; ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N,N Examples of suitable esters include unsaturated fatty acid amides such as N,N'-dioleyl adipamide and N,N'-dioleyl sebacamide; aromatic bisamides such as m-xylene bisstearamide and N,N'-distearyl isophthalamide; fatty metal salts (commonly known as metal soaps) such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes obtained by grafting aliphatic hydrocarbon waxes with vinyl copolymerizable monomers such as styrene and acrylic acid; partial esters of fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds with hydroxy groups obtained by hydrogenating vegetable oils and fats.

Waxes particularly preferred for use in the present invention are aliphatic hydrocarbon waxes. Examples include low-molecular-weight hydrocarbons obtained by radical polymerization of alkylenes under high pressure or polymerization using a Ziegler catalyst or metallocene catalyst under low pressure; Fischer-Tropsch wax synthesized from coal or natural gas; olefin polymers obtained by thermal cracking of high-molecular-weight olefin polymers; synthetic hydrocarbon waxes obtained from the distillation residue of hydrocarbons obtained by the Arge process from synthesis gas containing carbon monoxide and hydrogen, or synthetic hydrocarbon waxes obtained by hydrogenating these. Furthermore, hydrocarbon waxes fractionated by press sweating, solvent method, vacuum distillation, or fractional crystallization are more preferred. Waxes synthesized by methods other than alkylene polymerization are particularly preferred due to their molecular weight distribution.

The wax may be added during toner production or during binder resin production. These waxes may be used alone or in combination of two or more. It is preferable to add 1 to 20 parts by weight of wax per 100 parts by weight of binder resin.

<Charge control agent>
The toner of the present invention can use a known charge control agent as the charge control agent. Examples of known charge control agents include azo iron compounds, azo chromium compounds, azo manganese compounds, azo cobalt compounds, azo zirconium compounds, chromium compounds of carboxylic acid derivatives, zinc compounds of carboxylic acid derivatives, aluminum compounds of carboxylic acid derivatives, and zirconium compounds of carboxylic acid derivatives. The carboxylic acid derivative is preferably an aromatic hydroxycarboxylic acid. Charge control resins can also be used. If necessary, one or more types of charge control agents may be used in combination. The charge control agent is preferably added in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the binder resin.

<Career>
The toner of the present invention may be used as a magnetic one-component developer, a non-magnetic one-component developer, or a two-component developer by mixing with a carrier. As the carrier, a carrier such as a normal ferrite or magnetite, or a resin-coated carrier may be used. A binder-type carrier core in which magnetic powder is dispersed in a resin may also be used.

Resin-coated carriers consist of carrier core particles and a coating material, which is a resin that coats the surfaces of the carrier core particles. Resins used in coating materials include styrene-acrylic resins such as styrene-acrylic acid ester copolymers and styrene-methacrylic acid ester copolymers; acrylic resins such as acrylic acid ester copolymers and methacrylic acid ester copolymers; fluorine-containing resins such as polytetrafluoroethylene, monochlorotrifluoroethylene polymers, and polyvinylidene fluoride; silicone resins; polyester resins; polyamide resins; polyvinyl butyral; and aminoacrylate resins. Other examples include ionomer resins and polyphenylene sulfide resins. These resins can be used alone or in combination.

<External additives>
In the toner of the present invention, it is preferable to externally add silica fine powder to toner particles in order to improve charging stability, developability, fluidity, and durability. The silica fine powder preferably has a specific surface area of 30 ^m2 /g or more and 500 m2/g or less, more preferably 50 ^m2 /g or more and 400 ^m2 /g or less, as measured by the ^BET method using nitrogen adsorption. Furthermore, it is preferable to use 0.01 parts by mass or more and 8.00 parts by mass or less, more preferably 0.10 parts by mass or more and 5.00 parts by mass or less, of silica fine powder per 100 parts by mass of toner particles.

The BET specific surface area of silica fine powder can be calculated using the multi-point BET method by adsorbing nitrogen gas onto the surface of the silica fine powder using, for example, a specific surface area measuring device such as Autosorb 1 (Yuasa Ionics), GEMINI 2360/2375 (Micrometilik), or Tristar 3000 (Micrometilik).

If necessary, the silica fine powder may be treated with a treating agent such as unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane coupling agents, silane compounds with functional groups, or other organosilicon compounds, or a combination of various treating agents, for the purposes of hydrophobization and triboelectric charge control.

Furthermore, other external additives may be added to the toner of the present invention as needed. Examples of such external additives include resin particles and inorganic fine powders that function as charge adjuvants, conductivity imparting agents, fluidity imparting agents, caking inhibitors, release agents during heat roller fixing, lubricants, abrasives, etc. Charge adjuvants include metal oxides such as titanium oxide, zinc oxide, and alumina. Lubricants include polyethylene fluoride powder, zinc stearate powder, and polyvinylidene fluoride powder. Abrasives include cerium oxide powder, silicon carbide powder, and strontium titanate powder.

<Manufacturing method>
The method for producing the toner particles in the present invention is not particularly limited, and they can be produced by known methods, such as a pulverization method, an emulsion aggregation method, a suspension polymerization method, and a dissolution suspension method.

Toner particles produced by the pulverization method are produced, for example, as follows: Binder resin, resin composition, colorant, and, if necessary, other additives are thoroughly mixed in a mixer such as a Henschel mixer or ball mill. The mixture is melted and kneaded using a thermal kneader such as a twin-screw kneading extruder, heated roll, kneader, or extruder. Wax, magnetic iron oxide particles, and metal-containing compounds can also be added during this process. The molten mixture is cooled and solidified, and then pulverized and classified to obtain toner particles. The average circularity of the toner particles can be controlled by adjusting the exhaust temperature during pulverization. If necessary, the toner particles and external additives can be mixed in a mixer such as a Henschel mixer to obtain toner.

Examples of mixers include the following: Henschel Mixer (manufactured by Mitsui Mining Co., Ltd.); Super Mixer (manufactured by Kawata Corporation); Ribocone (manufactured by Okawara Manufacturing Co., Ltd.); Nauta Mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Corporation); Spiral Pin Mixer (manufactured by Pacific Machinery Works Co., Ltd.); and Lödige Mixer (manufactured by Matsubo Corporation).

Examples of kneading machines include the following: KRC Kneader (Kurimoto Iron Works); Buss Co. Kneader (Buss); TEM type extruder (Toshiba Machine Co.); TEX twin-screw kneader (The Japan Steel Works); PCM kneader (Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (Inoue Seisakusho); Kneadex (Mitsui Mining Co.); MS pressure kneader, Kneader-Ruder (Moriyama Seisakusho); Banbury mixer (Kobe Steel, Ltd.).

Examples of pulverizers include: Counter Jet Mill, Micron Jet, Inomizer (manufactured by Hosokawa Micron Corporation); IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross Jet Mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Industrial Co., Ltd.); Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

If necessary, after grinding, the toner particles can be surface-treated using a Hybridization System (manufactured by Nara Machinery Works), Nobilta (manufactured by Hosokawa Micron Corporation), Mechanofusion System (manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation), Innomizer (manufactured by Hosokawa Micron Corporation), Theta Composer (manufactured by Tokuju Kogyosho Co., Ltd.), Mechanomill (manufactured by Okada Seiko Co., Ltd.), or Meteoraidbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.) to control the average circularity of the toner particles.

Classifiers include the following: Cruseal, Micron Classifier, and Spedic Classifier (manufactured by Seishin Enterprises); Turbo Classifier (manufactured by Nisshin Engineering); Micron Separator, Turboplex (ATP), and TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Industry Co., Ltd.); and YM Microcut (manufactured by Yaskawa Shoji Co., Ltd.).

Sieving devices used to sift coarse particles include the following: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonaseave, Gyrosifter (Tokuju Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Industry Co., Ltd.); Microsifter (manufactured by Makino Sangyo Co., Ltd.); and circular vibrating sieve.

<Methods for measuring various physical properties>
Next, the measurement methods for the raw materials and toner according to the present invention will be described.

(Measurement of Toner Particle Size Distribution)
On the "Change Standard Measurement Method (SOM) screen" of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particles 10.0 μm" (manufactured by Beckman Coulter). Press the threshold/noise level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the "Flush aperture tube after measurement" box.

In the dedicated software's "Pulse to particle size conversion setting screen," set the bin spacing to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) Pour approximately 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture flush" function of the dedicated software to remove dirt and air bubbles from inside the aperture tube.
(2) Approximately 30 ml of the aqueous electrolytic solution is placed in a 100 ml flat-bottom glass beaker, and approximately 0.3 ml of a dilution obtained by diluting "Contaminon N" (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added thereto as a dispersant.
(3) A predetermined amount of ion-exchanged water was placed in the water tank of an ultrasonic disperser "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) that had two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees and an electrical output of 120 W, and about 2 ml of the Contaminon N was added to this water tank.
(4) The beaker (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height of the beaker is adjusted so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized.
(5) While the electrolyte solution in the beaker in (4) is being irradiated with ultrasonic waves, approximately 10 mg of toner particles are added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C.
(6) The (5) electrolytic solution in which the toner particles have been dispersed is dropped using a pipette into the (1) round-bottom beaker placed in the sample stand, and the measurement concentration is adjusted to about 5%. Then, measurement is continued until the number of particles measured reaches 50,000.
(7) The measurement data is analyzed using the dedicated software provided with the device to calculate the weight-average particle size (D4). Note that when the dedicated software is set to graph/volume %, the "average diameter" on the analysis/volume statistics (arithmetic mean) screen is the weight-average particle size (D4).

(Method for measuring average circularity)
The average circularity of the toner particles is measured using a flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions at the time of calibration.

The specific measurement method is as follows. First, approximately 20 mL of ion-exchanged water, from which impurities such as solids have been removed, is placed in a glass container. Approximately 0.2 mL of a solution prepared by diluting Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder; manufactured by Wako Pure Chemical Industries, Ltd.) approximately three times by weight with ion-exchanged water is added as a dispersant. Approximately 0.02 g of the measurement sample is then added, and the mixture is dispersed for two minutes using an ultrasonic disperser to obtain a dispersion for measurement. The dispersion is then appropriately cooled so that its temperature remains between 10°C and 40°C. A tabletop ultrasonic cleaner disperser (VS-150, manufactured by Vervoclear Co., Ltd.) with an oscillation frequency of 50 kHz and an electrical output of 150 W is used as the ultrasonic disperser. A predetermined amount of ion-exchanged water is placed in the water tank, and approximately 2 mL of Contaminon N is added to the water tank.

The measurement was performed using the flow particle image analyzer equipped with a standard objective lens (10x magnification), and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the procedure described above was introduced into the flow particle image analyzer, and 3,000 toner particles were measured in HPF measurement mode and total count mode. The binarization threshold for particle analysis was set to 85%, and the analyzed particle diameter was limited to a circle-equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles was determined.

Before starting the measurement, automatic focus adjustment is performed using standard latex particles (Duke Scientific's "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" diluted with ion-exchanged water). Thereafter, it is recommended to perform focus adjustment every two hours after starting the measurement.

In the examples of this application, a flow-type particle image analyzer was used that had been calibrated by Sysmex Corporation and had a calibration certificate issued by Sysmex Corporation. Measurements were carried out under the same measurement and analysis conditions as when the calibration certificate was received, except that the particle diameters analyzed were limited to equivalent-circle diameters of 1.985 μm or more and less than 39.69 μm.

(Measurement of Glass Transition Temperature (Tg) of Binder Resin and Toner)
The glass transition temperature of the resin is measured in accordance with ASTM D3418-82 using a differential scanning calorimeter "Q2000" (manufactured by TA Instruments).

The melting points of indium and zinc are used to correct the temperature of the device's detection section, and the heat of fusion of indium is used to correct the amount of heat.

Specifically, about 3 mg of resin or toner is precisely weighed and placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is carried out under the following conditions.
Temperature increase rate: 10°C/min
Measurement start temperature: 30℃
Measurement end temperature: 180°C

Measurements are made at a heating rate of 10°C/min within the measurement range of 30 to 180°C. The temperature is raised to 180°C once and held there for 10 minutes, then lowered to 30°C, and then raised again. During this second heating process, the specific heat change is obtained in the temperature range of 30 to 100°C. The point at which the line midpoint between the baselines before and after the specific heat change intersects with the differential thermal curve is taken as the glass transition temperature (Tg) of the resin.

(Measurement of Softening Point (Tm) of Binder Resin)
In the present invention, the softening point (Tm) of the resin can be measured using a constant load extrusion type capillary rheometer "Flow characteristic evaluation device Flow Tester CFT-500D" (manufactured by Shimadzu Corporation).

The CFT-500D is an instrument that applies a constant load from above using a piston while heating and melting the measurement sample filled in a cylinder and forcing it out through a capillary hole at the bottom of the cylinder. It is capable of graphing a flow curve based on the piston's descent distance (mm) and temperature (°C).

In the present invention, the softening point (Tm) is defined as the "melting temperature in the 1/2 method" described in the manual accompanying the "Flow Property Evaluation Device Flow Tester CFT-500D."

The melting temperature in the 1/2 method is calculated as follows:

First, find half the difference between the amount of piston descent when outflow ends (end of outflow, Smax) and the amount of piston descent when outflow begins (minimum point, Smin) (this is X; X = (Smax - Smin) / 2). Then, the temperature on the flow curve when the amount of piston descent is the sum of X and Smin is taken as the melting temperature in the 1/2 method.

The measurement sample is prepared by compressing 1.2 g of resin at 10 MPa for 60 seconds using a tablet press (e.g., a standard manual Newton press NT-100H, manufactured by NPA Systems) at 25°C to form a cylindrical shape with a diameter of 8 mm.

Specific measurement procedures should be performed according to the manual provided with the device.

The measurement conditions for CFT-500D are as follows.
Test mode: Temperature rising method Starting temperature: 40°C
Achieved temperature: 200℃
Measurement interval: 1.0°C
Temperature increase rate: 4.0°C/min
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 5.0 kgf
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0 mm

(Measurement of weight average molecular weight)
The weight average molecular weight of the resin composition is measured using gel permeation chromatography (GPC) as follows.

First, place the sample in tetrahydrofuran (THF) and leave it at 25°C for several hours. Then, shake thoroughly to mix well with the THF, and leave it to stand for another 12 hours or more until the sample no longer clumps together.

The solution is left in the THF for 24 hours. The resulting solution is then passed through a sample processing filter (pore size 0.2 μm to 0.5 μm, for example, Myshoridisc H-25-2 (manufactured by Tosoh Corporation)) to prepare the GPC sample.

The sample concentration should be adjusted to between 0.5 mg/ml and 5.0 mg/ml. This sample solution is used for measurements under the following conditions.

The column is stabilized in a heat chamber at 40°C, and tetrahydrofuran (THF) is passed through the column at this temperature as a solvent at a flow rate of 1 ml per minute. Approximately 100 μl of the sample solution is injected and measured.

The column is a combination of several commercially available polystyrene gel columns, such as a combination of Shodex GPC KF-801, 802, 803, 804 _, 805, 806, 807, and 800P manufactured by Showa Denko K.K., or a combination of TSKgel G1000H (H _XL ), G2000H (H _XL ), G3000H (H _XL ), G4000H (H XL), G5000H (H _XL ), G6000H (H _XL ), and G7000H (H _XL ) and TSKguard columns manufactured by Tosoh Corporation.

When measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithm of the calibration curve created using several monodisperse polystyrene standard samples and the count value.

The standard polystyrene samples used to prepare the calibration curve are those manufactured by Tosoh Corporation or Showa Denko Co., Ltd., with molecular weights of approximately 1 x ¹⁰ to 1 x ¹⁰ , and at least 10 standard polystyrene samples are used. An RI (refractive index) detector is used as the detector.

(Measurement of Acid Value of Binder Resin and Resin Composition)
The acid value of the binder resin and the resin composition is measured by the following method. The acid value is the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of sample. The acid value of the polyester resin is measured in accordance with JIS K 0070-1992. Specifically, the following procedure is followed.

(1) Preparation of Reagents 1.0 g of phenolphthalein was dissolved in 90 ml of ethyl alcohol (95 vol%), and deionized water was added to make the total volume 100 ml to obtain a phenolphthalein solution.

Dissolve 7 g of special-grade potassium hydroxide in 5 ml of deionized water and add ethyl alcohol (95 vol%) to make 1 liter. Place in an alkali-resistant container to avoid contact with carbon dioxide and leave for 3 days, then filter to obtain potassium hydroxide solution. Store the resulting potassium hydroxide solution in an alkali-resistant container. The factor of the potassium hydroxide solution is determined by placing 25 ml of 0.1 mol/L hydrochloric acid in an Erlenmeyer flask, adding a few drops of the phenolphthalein solution, and titrating with the potassium hydroxide solution to determine the amount of potassium hydroxide solution required for neutralization. Use 0.1 mol/L hydrochloric acid prepared in accordance with JIS K 8001-1998.

(2) Procedure (A) Main Test: 2.0 g of crushed polyester resin sample was weighed accurately into a 200 ml Erlenmeyer flask, and 100 ml of a toluene:ethanol (2:1) mixed solution was added and dissolved over 5 hours. Next, several drops of the phenolphthalein solution were added as an indicator, and titration was carried out using the potassium hydroxide solution. The endpoint of the titration was when the light red color of the indicator persisted for approximately 30 seconds.

(B) Blank Test: A titration is carried out in the same manner as above, except that no sample is used (i.e., only a mixed solution of toluene:ethanol (2:1) is used).

(3) The obtained results are substituted into the following formula to calculate the acid value.
A=[(CB)×f×5.61]/S
where A is the acid value (mg KOH/g), B is the amount (ml) of potassium hydroxide solution added for the blank test, C is the amount (ml) of potassium hydroxide solution added for the main test, f is the factor of the potassium hydroxide solution, and S is the sample (g).

(Measurement of infrared absorption spectrum)
FT-IR spectra by the ATR method were measured using a Spectrum One (Fourier transform infrared spectrometer) manufactured by PerkinElmer equipped with a Universal ATR Sampling Accessory.

The incident angle of the infrared light was set to 45°.

A Ge ATR crystal (refractive index = 4.0) was used as the prism for the ATR measurements.

Other conditions are as follows:
Range
Start:4000cm ^-1
End: 600 cm ⁻¹ (ATR crystal of Ge)
Duration
Scan number: 4
Resolution:4.00cm ^-1
Advanced: CO ₂ /H ₂ O correction

The specific measurement procedure is as follows:

Calculation method of ratio (P2/P1):
(1) A Ge ATR crystal (refractive index = 4.0) is attached to the device.
(2) Set the Scan type to Background and the Units to EGY to measure the background.
(3) Set Scan type to Sample and Units to A.
(4) 0.01 g of the sample is precisely weighed onto the ATR crystal.
(5) Pressurize the sample with the pressure arm (Force Gauge is 100).
(6) Measure the sample.
(7) The obtained FT-IR spectrum is subjected to baseline correction using Automatic Correction.
(8) Calculate the maximum absorption peak intensity in the range of 1050 cm ⁻¹ or more and 1150 cm ⁻¹ or less. (P2)
(9) Calculate the maximum absorption peak intensity in the range of 2800 cm ⁻¹ or more and 2900 cm ⁻¹ or less. (P1)
(10) Calculate the ratio (P2/P1).

The basic structure and features of the present invention have been described above. The present invention will now be explained in more detail based on examples. However, the present invention is in no way limited to these examples. Unless otherwise specified, parts are by weight.

<Production Example of Binder Resin PL1>
Bisphenol A ethylene oxide (2.2 mole adduct): 50.0 parts by mole Bisphenol A propylene oxide (2.2 mole adduct): 50.0 parts by mole Terephthalic acid: 90.0 parts by mole Trimellitic anhydride: 10.0 parts by mole 100 parts of the monomers constituting the polyester unit were mixed together with 500 ppm of titanium tetrabutoxide in a 5-liter autoclave.

The autoclave was equipped with a reflux condenser, a water separator, an _N2 gas inlet tube, a thermometer, and a stirrer, and a condensation polymerization reaction was carried out at 230°C while introducing _N2 gas into the autoclave. The reaction time was adjusted to obtain the desired softening point, and after the reaction was completed, the resin was removed from the vessel, cooled, and pulverized to obtain binder resin PL1. The binder resin PL1 had a Tm of 102°C, a Tg of 55°C, and no melting point.

<Production Example of Binder Resin PL2>
Binder resin PL2 was obtained in the same manner as in the production example for binder resin PL1, except that the type and amount of monomer were changed and Tm and Tg were changed by adjusting the reaction time as shown in Table 1. The physical properties of the obtained binder resin PL2 are shown in Table 1.

<Production Example of Binder Resin PL3>
Styrene 70 parts n-monobutyl acrylate 24 parts monobutyl maleate 6 parts 2,2-bis(4,4-di-t-butyl-oxycyclohexyl)propane 1 part While stirring 200 parts of xylene in a four-neck flask, the atmosphere in the four-neck flask was thoroughly replaced with nitrogen and the temperature was raised to 120°C, and then the above components were added dropwise into the four-neck flask over 3.5 hours. Further polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure to obtain binder resin PL3, which is a vinyl resin. The physical properties of the obtained binder resin PL3 are shown in Table 1.

<Production Example of Binder Resin PH1>
Bisphenol A ethylene oxide (2.2 mole adduct): 50.0 mole parts Bisphenol A propylene oxide (2.2 mole adduct): 50.0 mole parts Terephthalic acid: 90.0 mole parts The above materials were weighed into a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. Furthermore, 500 ppm of titanium tetrabutoxide was added to the reaction vessel. Next, the atmosphere in the flask was replaced with nitrogen gas, and the temperature was gradually increased while stirring, and the mixture was allowed to react for 2 hours at 200°C while stirring.

The pressure inside the reaction vessel was then reduced to 8.3 kPa and maintained at this pressure for 1 hour, after which the vessel was cooled to 180 kPa and returned to atmospheric pressure (first reaction step).
Trimellitic anhydride: 10.0 parts by mole Then, the above materials and 0.003 parts by mole of tert-butylcatechol (polymerization inhibitor) were charged into a reaction vessel, the pressure inside the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 160°C. After confirming that the softening point measured in accordance with ASTM D36-86 had reached 151°C, the temperature was reduced to stop the reaction (second reaction step), thereby obtaining a binder resin PH1. The obtained binder resin PH1 had a softening point (Tm) of 151°C, a glass transition temperature (Tg) of 59°C, and no melting point.

<Production Example of Resin Composition PA1>
In an autoclave reactor equipped with a thermometer and a stirrer, 300.0 parts of xylene and 15.0 parts of polypropylene (weight average molecular weight 3.8 x 10 ⁴ ) were added and thoroughly dissolved. After nitrogen substitution, a mixed solution of 63.74 parts of styrene, 4.72 parts of cyclohexyl methacrylate, 3.54 parts of methacrylic acid, 13.0 parts of methoxypolyethylene glycol acrylate, and 250.0 parts of xylene was added dropwise at 180 ° C. for 3 hours to polymerize. The mixture was then held at this temperature for 30 minutes, and the solvent was removed to obtain a resin composition PA1. The ATR index (P1/P2), acid value, and weight average molecular weight of the resulting resin composition PA1 are shown in Table 2.

<Production Examples of Resin Compositions PA2 to PA9>
Resin compositions PA2 to 9 were obtained in the same manner as for resin composition PA1, except that the components and amounts were changed as shown in Table 2. The ATR index (P1/P2), acid value, and weight average molecular weight of the obtained resin compositions PA2 to 9 are shown in Table 2.

Example 1
(Production Example of Toner 1)
Binder resin PL1 70 parts Binder resin PH1 30 parts Resin composition PA1 10 parts Fischer-Tropsch wax (FNP0090, melting point: 90°C) 6 parts C.I. Pigment Blue 15:3 5 parts The above materials were premixed in a Henschel mixer, and then melt-kneaded at 160°C using a twin-screw kneading extruder.

The resulting kneaded material was cooled, coarsely pulverized in a hammer mill, and then finely pulverized in a turbo mill.

The resulting finely pulverized material was classified using a multi-division classifier utilizing the Coanda effect, yielding negatively triboelectrically charged toner particles with a weight-average particle size (D4) of 6.5 μm and an average circularity of 0.952.

2.0 parts of hydrophobized silica fine particles (specific surface area of 140 m ² /g as measured by nitrogen adsorption using the BET method) were externally added to 100 parts of the toner particles, and the mixture was sieved through a mesh with 150 μm openings to obtain Toner 1.

The above toner 1 and magnetic carrier were mixed using a V-type mixer (V-10 type: Tokuju Seisakusho Co., Ltd.) under conditions of 0.5 s ⁻¹ and a rotation time of 5 minutes so that the toner concentration would be 10% by mass, to prepare developer 1. The magnetic carrier used was magnetic ferrite carrier particles (number average particle size: 38 μm) surface-coated with acrylic resin.

The following evaluations were carried out using the resulting developer 1.

[Evaluation of Toner Coloring Power]
The image density of the images prepared under the following conditions was evaluated: The image density was measured using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite Corporation).
Paper: OK-TOP coated paper (basis weight 128.0g/m ² )
Toner amount: 0.35 mg/cm ²
Evaluation image: Solid image of 5 ^cm2 or more on paper Image fixing environment: Temperature 25°C/Humidity 50% RH
Fixing speed: 360 mm/sec
Fixing temperature: 180°C

Image density was measured at three points on the same image, and the toner's coloring power was calculated from the average value.

(Evaluation criteria)
A: Image density 1.40 or more B: Image density 1.30 or more and less than 1.40 C: Image density 1.20 or more and less than 1.30 D: Image density less than 1.20

[Evaluation of high-temperature offset resistance]
An unfixed image was formed under the following conditions: A modified imagePRESS C910 was used as the image forming apparatus.
Paper: CS-680 (68.0g/m ² )
Toner loading: 0.08 mg/cm ²
Image processing: error diffusion The unfixed image prepared above was passed through a fixing unit in an environment of 23°C temperature and 5% humidity. The process speed was fixed at 360 mm/sec, and the temperature of the fixing belt was set in 5°C increments from 120°C to 230°C. The images passed through at each temperature were measured using a reflectometer (REFLECTOMETER MODEL TC-6DS, manufactured by Tokyo Denshoku) to measure the average reflectance Dr (%) of the evaluation paper before image output and the reflectance Ds (%) of the white background area after the fixing test, and the fog was calculated using the following formula. From the obtained fog, the fixing temperature at which the fog value became 0.5% was calculated as the high-temperature offset occurrence temperature, and high-temperature offset resistance was evaluated.
Fog (%) = Dr (%) - Ds (%)

(Evaluation criteria)
A: High-temperature offset occurrence temperature 180°C or higher B: High-temperature offset occurrence temperature 160°C or higher but lower than 180°C C: High-temperature offset occurrence temperature 140°C or higher but lower than 160°C D: High-temperature offset occurrence temperature lower than 140°C

[Charging Stability Evaluation]
A modified ImagePRESS C910 was used as the image forming apparatus. Developer 1, which had been left in a high-temperature, high-humidity environment (temperature 32.5°C, humidity 80% RH) for 24 hours, was loaded into the developing machine, and the loading on the electrostatic latent image carrier was adjusted to 0.40 mg/ ^cm2 . The developing machine was allowed to idle for 2 minutes inside the main body, and the developing bias was adjusted so that the density of the solid image would be 1.35.

With the power to the main unit still on, the developing unit was removed from the machine and left for two weeks in an environment with a temperature of 32.5°C and a humidity of 80% RH. After leaving it there, the developing unit was returned to the main unit, a solid image was printed, and the density was measured.

The image density before storage was set at 100%, and the density maintenance rate after storage was calculated and evaluated.

(Evaluation criteria)
A: Density maintenance rate of 95% or more B: Density maintenance rate of 90% or more but less than 95% C: Density maintenance rate of 85% or more but less than 90% D: Density maintenance rate of less than 85%

Developer 1 received an A rating for all of the above evaluation items.

[Examples 2 to 16, Comparative Examples 1 to 3]
(Production Examples of Toners 2 to 19)
Toners 2 to 19 were obtained in the same manner as in the production example of Toner 1, except that the types and amounts of binder resin and colorant were changed as shown in Table 3.

(Production Examples of Developers 2 to 19)
Developers 2 to 19 were obtained in the same manner as in the production example of developer 1, except that the toner was changed as shown in Table 4. Furthermore, evaluations were carried out in the same manner as for developer 1. The evaluation results are shown in Table 4.

Claims (7)

A toner having toner particles containing a binder resin, a colorant, and a resin composition,
The resin composition contains a polyolefin unit and a unit represented by the following formula (1):
The toner is characterized in that the colorant is an organic pigment.
(n represents 3≦n≦10. R1 and R2 each independently represent H or _CH3 .) The toner according to claim 1, wherein the organic pigment is any one of C.I. Pigment Blue 15:3, C.I. Pigment Red 122, and C.I. Pigment Red 150. The toner according to claim 1 or 2, wherein the toner particles contain 3 to 20 parts by mass of the resin composition per 100 parts by mass of the binder resin. The toner according to any one of claims 1 to 3, wherein the binder resin is polyester. The toner according to any one of claims 1 to 4, wherein the resin composition is a polymer in which a styrene-acrylic unit is grafted to the polyolefin unit. The toner according to claim 5, wherein the styrene acrylic unit contains a unit derived from methoxypolyethylene glycol acrylate. The resin composition exhibited the following FT-IR spectrum measured by an ATR method using Ge as an ATR crystal at an incident angle of infrared light of 45°:
The maximum absorption peak intensity in the range of 2800 cm ⁻¹ to 2900 cm ⁻¹ is P1,
The maximum absorption peak intensity in the range of 1050 cm ⁻¹ to 1150 cm ⁻¹ is P2
7. The toner according to claim 1, wherein the ratio of P1 to P2 (P2/P1) is 1.3 or more and 3.0 or less.