JP7516206B2 - Color toner set, image forming method, and image forming apparatus - Google Patents

Description

The present invention relates to a color toner set, an image forming method, and an image forming apparatus for use in electrophotography, electrostatic recording, electrostatic printing, and toner jet systems.

In recent years, as full-color copying machines of the electrophotographic type have come into widespread use, there has been a demand for even higher image quality. In particular, in full-color copying machines, there has been an increasing demand for color reproducibility so that images faithful to the original can be obtained. Therefore, color toners for forming color images are required to have good color reproducibility.
Therefore, in order to improve the color reproducibility of color toners, various colorants have been investigated for each color.
Japanese Patent Application Laid-Open No. 2003-233692 proposes a magenta toner that uses a xanthene dye in order to improve the color reproducibility of the magenta toner.
Further, a color toner set consisting of a yellow toner, a magenta toner, and a cyan toner has been studied to improve color reproducibility.
Japanese Patent Laid-Open No. 2003-233693 proposes a toner set that improves color reproducibility by specifying colorants used in the yellow toner, magenta toner, and cyan toner used in image formation.

JP 2009-80478 A JP 2010-2897 A

However, the toner disclosed in Patent Document 1 and the toner set disclosed in Patent Document 2 are insufficient in color reproducibility to meet the high demands of recent years.
The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a toner having excellent color reproducibility.

According to one aspect of the present invention, there is provided a color toner set having a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion,
The yellow toner is
a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester;
The polyester resin composition contains a tin compound containing a carbon atom in an amount of 0.005 parts by mass or less per 100 parts by mass of the polyester resin,
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is contained in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester,
A color toner set is provided that contains up to 0.005 parts by weight of a titanium compound containing a carbon atom per 100 parts by weight of the polyester.

According to another aspect of the present invention, there is provided an image forming method having a developing step of developing an electrostatic latent image on an image carrier with toner to form a toner image on the image carrier, comprising the steps of:
the toners include a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion,
The yellow toner is
a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester;
The content of a tin compound containing a carbon atom is 0.005 parts by mass or less per 100 parts by mass of the polyester,
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is used in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
An image forming method is provided which contains a titanium compound containing a carbon atom in an amount of 0.005 parts by weight or less per 100 parts by weight of the polyester.

According to another aspect of the present invention, there is provided an image forming apparatus having an image carrier and a developing means for developing an electrostatic latent image on the image carrier with toner to form a toner image on the image carrier, comprising:
the toner comprises a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion,
The yellow toner is
a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester;
The polyester resin composition contains a tin compound containing a carbon atom in an amount of 0.005 parts by mass or less per 100 parts by mass of the polyester resin,
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is used in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
An image forming apparatus is provided which contains a titanium compound containing a carbon atom in an amount of 0.005 parts by weight or less per 100 parts by weight of the polyester.

The present invention provides a color toner set with excellent color reproducibility.

1 is a cross-sectional view illustrating an example of a schematic configuration of an image forming apparatus according to an embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the present invention is not limited to the following embodiment.
In the present invention, the expressions "xx or more and xx or less" and "xx to xx" expressing a numerical range mean a numerical range including the endpoints, that is, the lower limit and the upper limit, unless otherwise specified.
A toner set, an image forming method, and an image forming apparatus that are preferable in the present invention will be described in detail below.
The present invention provides a color toner set having a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion.
The yellow toner is
A titanium compound containing a carbon atom is contained in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester,
The polyester resin contains a tin compound containing a carbon atom in an amount of 0.005 part by mass or less per 100 parts by mass of the polyester.
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is contained in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester,
The titanium compound containing a carbon atom is contained in an amount of 0.005 part by mass or less per 100 parts by mass of the polyester.

With regard to color reproducibility, it is not important that only a certain color has high saturation or brightness, but rather that the color gamut of the color toner set is well-balanced and large. For example, this can be said to be close to the color gamut of Japan Color, which is a color reproduction standard in the printing industry. In order to make the color gamut of a color toner set close to the color gamut of Japan Color, it has been common to make the chromaticity points of the primary colors yellow, magenta, and cyan close to the chromaticity points of the corresponding primary colors of Japan Color.
However, in order to make the color gamut of a color toner set closer to that of Japan Color, it is important to make the chromaticity points of the secondary colors of red, green, and blue, which have a large difference from Japan Color, closer to the chromaticity points of the corresponding secondary colors of Japan Color. Conventionally, attempts have been made to make the chromaticity points of Japan Color closer to those of Japan Color by adjusting the type and amount of each color material in the toner of each color.
However, as a result of extensive research conducted by the present inventors, it has been found that the following is effective in bringing the color gamut of the color toner set closer to the color gamut of Japan Color, that is, in improving color reproducibility.
Yellow toner containing a resin having a polyester portion contains a titanium compound containing a carbon atom. Magenta toner and cyan toner containing a resin having a polyester portion contain a tin compound containing a carbon atom.

The mechanism by which the effects of the present invention are manifested is speculated to be as follows. Titanium compounds often have the property of easily reacting with multiple hydroxyl groups. It is believed that this causes a reaction with the hydroxyl groups of the polyester to form coordinate bonds. In this case, if the titanium compound contains a carbon atom, the carbon atom is present between the titanium compound, which is an inorganic substance, and the polyester, which is an organic substance, thereby increasing the interaction between the titanium compound and the polyester. As a result, it is believed that the length of conjugation due to the coordinate bond between the titanium compound and the polyester (the length of the molecular chain formed by the π-electron conjugated bond) mainly absorbs light in the blue region.

On the other hand, tin compounds often have the property of easily reacting with multiple carboxyl groups. For this reason, it is believed that they react with the carboxyl groups of the polyester to form coordinate bonds. In this case, if the tin compound contains a carbon atom, the carbon atom is present between the tin compound, which is an inorganic substance, and the polyester, which is an organic substance, and this increases the interaction between the tin compound and the polyester. As a result, it is believed that the length of conjugation due to the coordinate bond between the tin compound and the polyester mainly absorbs light in the yellow region.

Therefore, when red is developed using a color toner set consisting of the yellow toner and magenta toner described below, the light absorption effect due to the conjugation length of the coordinate bond described above results in steep absorption of light, particularly at wavelengths of 610 nm or less, improving the color development of red, which approaches the chromaticity point of Japan Color red.
A yellow toner containing a titanium compound containing the carbon atom. A magenta toner containing a tin compound containing the carbon atom.

In addition, when green is developed using a color toner set consisting of the following yellow toner and the following cyan toner, the light absorption effect due to the conjugation length of the coordinate bond is such that the absorption of light, particularly light of 500 nm or less, becomes steep, improving the color development of green, thereby approaching the chromaticity point of Japan Color green.
A yellow toner containing a titanium compound containing the carbon atom. A cyan toner containing a tin compound containing the carbon atom.

Furthermore, when blue is developed using a color toner set consisting of the magenta toner and the cyan toner, the light absorption effect due to the conjugation length of the coordinate bond is such that the absorption of light at 540 nm or more is steep, improving the blue color development, thereby approaching the chromaticity point of Japan Color blue.
- Magenta toner containing a tin compound containing the above carbon atom - Cyan toner containing a tin compound containing the above carbon atom Therefore, by using the above color toner set, the chromaticity points of each secondary color will approach the chromaticity points of the corresponding secondary colors of Japan Color, and as a result, the color gamut as a whole will approach the color gamut of Japan Color, thereby improving color reproducibility.

Examples of the titanium compound containing a carbon atom that is preferably used in the present invention include titanium alkoxides, aromatic carboxylic acid titanium compounds, and titanium compounds containing an alcohol aminate unit.
Specifically, the following compounds are mentioned.
Examples of titanium alkoxides include tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetra(n-butyl) titanate, tetraoctyl titanate, and tetrastearyl titanate.

Examples of aromatic titanium carboxylate compounds include the following: titanium phthalate, titanium isophthalate, titanium terephthalate, titanium trimellitate, titanium pyromellitate, titanium 1,3-naphthalene dicarboxylate, titanium 2,4,6-naphthalene tricarboxylate, and titanium salicylate.

The aromatic carboxylic acid titanium compound is preferably a reaction product of an aromatic carboxylic acid and a titanium alkoxide.
The aromatic carboxylic acid is more preferably a divalent or higher aromatic carboxylic acid (that is, an aromatic carboxylic acid having two or more carboxy groups) and/or an aromatic oxycarboxylic acid.
Examples of the divalent or higher aromatic carboxylic acid include the following: dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and their anhydrides, polyvalent carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenone dicarboxylic acid, benzophenone tetracarboxylic acid, naphthalene dicarboxylic acid, naphthalene tricarboxylic acid, and naphthalene tetracarboxylic acid, and their anhydrides and esters.
Examples of the aromatic hydroxycarboxylic acid include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and tropic acid.
Among these, it is more preferable to use a divalent or higher carboxylic acid as the aromatic carboxylic acid, and it is particularly preferable to use isophthalic acid, terephthalic acid, trimellitic acid, or naphthalenedicarboxylic acid.

Titanium compounds containing alcohol amination units are also preferred because they have high reactivity with the hydroxyl groups of polyesters. Examples include the following: Titanium tetrakis(monoethanol aminate), titanium monohydroxytris(triethanol aminate), titanium dihydroxybis(triethanol aminate), titanium trihydroxytriethanol aminate, titanium dihydroxybis(diethanol aminate), titanium dihydroxybis(monoethanol aminate), titanium dihydroxybis(monopropanol aminate), titanium dihydroxybis(N-methyl diethanol aminate), titanium dihydroxybis(N-butyl diethanol aminate), reaction product of tetrahydroxytitanium and N,N,N'N'-tetrahydroxyethylethylenediamine, titanyl bis(triethanol aminate), titanyl bis(diethanol aminate), titanyl bis(monoethanol aminate), titanyl hydroxytriethanol aminate, titanyl isopropoxytriethanol aminate, and intramolecular or intermolecular polycondensates thereof.

These titanium compounds containing carbon atoms can be stably obtained, for example, by reacting commercially available titanium dialkoxybis (alcohol aminate; manufactured by DuPont, etc.) in the presence of water at 70 to 90° C. The polycondensate can be obtained by further distilling off the condensed water under reduced pressure at 100° C.
Among these titanium compounds containing carbon atoms, aromatic carboxylate titanium compounds and titanium compounds containing an alcohol aminate unit are preferred.
The titanium compounds containing the above carbon atoms are preferred because they more efficiently absorb yellow light through coordinate bonds with the polyester.

As the tin compound containing a carbon atom that is preferably used in the present invention, an organic tin compound and an inorganic tin compound are preferable. Specific examples include organic tin compounds such as dibutyltin dichloride, dibutyltin oxide, and diphenyltin oxide. Here, an organic tin compound refers to a compound having a Sn-C bond.

Furthermore, inorganic tin compounds having no Sn-C bond are also preferably used. Here, the inorganic tin compound refers to a compound having no Sn-C bond. Examples of inorganic tin compounds include unbranched alkyl tin carboxylates such as tin diacetate, tin dihexanoate, tin dioctanoate, and tin distearate; branched alkyl tin carboxylates such as tin dineopentylate and tin di(2-ethylhexanoate); tin carboxylates such as tin oxalate; and dialkoxy tins such as dioctyloxy tin and distearoyloxy tin.
Among these tin compounds containing carbon atoms, tin carboxylates and alkoxy tins are preferred.
The tin compounds containing the above carbon atoms are preferred because they more efficiently absorb yellow light through coordinate bonds with the polyester.

These titanium compounds containing carbon atoms and tin compounds containing carbon atoms can be added as polyester synthesis catalysts during condensation polymerization to uniformly disperse the tin compounds containing carbon atoms and titanium compounds containing carbon atoms in the polyester. As a result, the absorption of light of a specific wavelength by coordinate bonds occurs efficiently, which is most preferable. In other words, the tin compounds containing carbon atoms and the titanium compounds containing carbon atoms are preferably derived from polyester synthesis catalysts.
It is also possible to obtain a polyester containing a tin compound containing a carbon atom and a titanium compound containing a carbon atom by producing a polyester in advance and then adding and mixing a tin compound containing a carbon atom and/or a titanium compound containing a carbon atom.

Each of the color toner sets of the present invention contains a colorant. Examples of the colorant include the following.
As the colorant, a pigment may be used alone, or a dye and a pigment may be used in combination.
Examples of pigments for cyan toner include C.I. Pigment Blue 2, 3, 15:2, 15:3, 15:4, 16, and 17; C.I. Bat Blue 6; C.I. Acid Blue 45; and copper phthalocyanine pigments having 1 to 5 phthalimidomethyl groups substituted on the phthalocyanine skeleton.

Examples of pigments for magenta toner include the following: C.I. Pigment 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, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57:
1, 58, 60, 63, 64, 68, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; C.I. Pigment Violet 19; C.I. Bat Red 1, 2, 10, 13, 15, 23, 29, 35.

Dyes for magenta toner include the following: C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; C.I. Disperse Red 9; C.I. Solvent Violet 8, 13, 14, 21, 27; C.I. Disperse Violet 1; 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; C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

Dyes for cyan toner include C.I. Solvent Blue 70.
Yellow toner pigments include: C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; C.I. Vat Yellow 1, 3, 20.
Yellow toner dyes include C.I. Solvent Yellow 162.

The content of the colorant is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the binder resin, where the binder resin refers to the total of a resin having a polyester portion and other resins described below.
The color toner set of the present invention may contain a yellow toner, a magenta toner, and a cyan toner, and may also contain a black toner, a white toner, and a glitter toner.
Examples of colorants for black toner include carbon black, and toners toned to black using yellow, magenta and cyan colorants.

The resin having a polyester portion may be composed of only polyester portions, or may contain other units to the extent that the effect of the present invention is not impaired. In this case, the resin having a polyester portion is characterized in that it contains 50% by mass or more of polyester portions. If the content of the polyester portion is less than 50% by mass, the absorption of light of a specific wavelength due to coordinate bonds is significantly reduced, and the effect of the present invention is not fully exerted.
The resin having a polyester portion may be a typical resin composed of an alcohol component and an acid component, both of which are exemplified below.

Examples of alcohol components include the following. Ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexenedimethanol, hydrogenated bisphenol A, and bisphenol derivatives represented by the following formula (1). Bisphenols such as hydrogenated bisphenol A and bisphenol derivatives represented by the following formula (1), and aromatic polyhydric alcohols including 1,2-benzenedimethanol, 1,4-benzenedimethanol, and derivatives thereof are preferred. Bisphenols such as hydrogenated bisphenol A and bisphenol derivatives represented by the following formula (1) are more preferred.

[In the formula, 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 1 to 10.]
Further, examples of the alcohol component include polyhydric alcohols such as glycerin, pentaerythritol, sorbitol, sorbitan, and oxyalkylene ethers of novolak-type phenolic resins.

On the other hand, examples of divalent carboxylic acids constituting polyesters include the following: benzene dicarboxylic acids or their anhydrides, such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride; alkyl dicarboxylic acids or their anhydrides, such as succinic acid, adipic acid, sebacic acid, and azelaic acid; succinic acid or its anhydrides substituted with an alkyl or alkenyl group having 6 to 18 carbon atoms; unsaturated dicarboxylic acids or their anhydrides, such as fumaric acid, maleic acid, citraconic acid, and itaconic acid; and polyvalent carboxylic acids, such as trimellitic acid, pyromellitic acid, 1,2,3,4-butanetetracarboxylic acid, and benzophenonetetracarboxylic acid and their anhydrides.

The resin having a polyester moiety preferably has an aromatic ring, which facilitates the formation of a chromophore, thereby further enhancing the effect of improving color reproducibility.
In the production of the polyester, "other catalysts" that are usually used in the production of polyesters may be used. Examples of the "other catalysts" include metals such as antimony, aluminum, manganese, nickel, zinc, lead, iron, magnesium, calcium, and germanium; and compounds containing these metals. When using a single other catalyst, the titanium compound containing a carbon atom or the tin compound containing a carbon atom is added and mixed after the production of the amorphous polyester, and used in the production of the toner.

The toner according to the present invention contains a resin having a polyester portion as a binder resin. In addition to the above polyester, the following "other resins" can be added as binder resins in amounts that do not impair the effects of the present invention, for the purpose of improving pigment dispersibility and improving the charging stability and blocking resistance of the toner. In this case, it is preferable that the resin having a polyester portion is contained in an amount of 80.00 parts by mass or more per 100 parts by mass of the binder resin contained in the toner. By being in the above range, the effect of the present invention is more effectively achieved by absorbing light of a specific wavelength due to the coordinate bond between the titanium compound containing carbon atoms and the polyester, and between the tin compound containing carbon atoms and the polyester.

Examples of "other resins" include the following resins: homopolymers of styrene and its substitutes, such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, styrene-α-chloromethyl methacrylate copolymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, and styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenolic resins, naturally modified phenolic resins, naturally modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyester resins, polyurethanes, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone-indene resins, petroleum-based resins, etc.

The yellow toner according to the present invention is characterized in that it contains 0.05 to 2.00 parts by mass of a titanium compound containing a carbon atom per 100 parts by mass of the polyester portion of the resin having a polyester portion. If the content of the titanium compound containing a carbon atom is less than 0.05 parts by mass, the effect of improving color reproducibility due to the coordinate bond between the titanium compound containing a carbon atom and the polyester portion is reduced. If the content of the titanium compound containing a carbon atom is more than 2.00 parts by mass, the interaction between sites that are likely to react with the hydroxyl group of the titanium compound containing a carbon atom is strengthened. As a result, the coordinate bond between the titanium compound containing a carbon atom and the polyester portion is not sufficiently formed, and the effect of improving color reproducibility is reduced.

The magenta toner and cyan toner according to the present invention are characterized in that they contain 0.05 to 2.00 parts by mass of a tin compound containing a carbon atom per 100 parts by mass of the polyester portion of the resin having a polyester portion. If the content of the tin compound containing a carbon atom is less than 0.05 parts by mass, the effect of improving color reproducibility due to the coordinate bond between the tin compound containing a carbon atom and the polyester portion is reduced. If the content of the tin compound containing a carbon atom is more than 2.00 parts by mass, the interaction between sites that are likely to react with the carboxy group of the tin compound containing a carbon atom is strengthened. As a result, the coordinate bond between the tin compound containing a carbon atom and the polyester portion is not sufficiently formed, and the effect of improving color reproducibility is reduced.

The yellow toner according to the present invention is characterized in that the content of the tin compound containing a carbon atom is 0.005 parts by mass or less per 100 parts by mass of the polyester portion of the resin having a polyester portion. If the content of the tin compound containing a carbon atom is more than 0.005 parts by mass, the light absorption due to the coordinate bond between the tin compound containing a carbon atom and the polyester portion inhibits the development of yellow color, and the effect of improving color reproducibility is reduced.

The magenta toner and cyan toner according to the present invention are characterized in that the content of the titanium compound containing a carbon atom is 0.005 parts by mass or less per 100 parts by mass of the polyester part of the resin having a polyester part. If the content of the titanium compound containing a carbon atom is more than 0.005 parts by mass, the absorption of light by the coordinate bond between the titanium compound containing a carbon atom and the polyester part inhibits the color development of magenta and cyan, and the effect of improving color reproducibility is reduced.

The titanium atoms contained in the titanium compound containing carbon atoms are preferably contained in an amount of 10.00 to 25.00 parts by mass, and more preferably 15.00 to 25.00 parts by mass, per 100 parts by mass of the titanium compound containing carbon atoms. By setting the amount in the above range, the formation of a chromophore due to a coordinate bond between the polyester portion and the titanium compound containing carbon atoms is effectively expressed, and the effect of improving color reproducibility is further increased.

The tin atom contained in the tin compound containing a carbon atom is preferably 18.00 to 51.00 parts by mass, and more preferably 29.00 to 46.00 parts by mass, per 100 parts by mass of the tin compound containing a carbon atom. By setting the amount in the above range, the formation of a chromophore due to a coordinate bond between the polyester portion and the tin compound containing a carbon atom is effectively expressed, and the effect of improving color reproducibility is further increased.

Wax may be used in the toner according to the present invention. Examples of wax include the following: hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxides of hydrocarbon waxes such as oxidized polyethylene wax or block copolymers thereof; waxes containing fatty acid esters as the main component such as carnauba wax; and partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax.

Further examples include: saturated straight-chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassidic acid, eleostearic acid, and parinaric acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; esters of fatty acids such as palmitic acid, stearic acid, behenic acid, and montanic acid with alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; 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. unsaturated fatty acid amides such as ethylene bisoleamide, hexamethylene bisoleamide, 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 grafted onto aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; partial esters of fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds having hydroxyl groups obtained by hydrogenating vegetable oils and fats.

Among these waxes, from the viewpoint of further improving hot offset resistance, preferred are hydrocarbon waxes such as paraffin wax, Fischer-Tropsch wax, and fatty acid ester waxes such as carnauba wax. In the present invention, from the viewpoint of further improving hot offset resistance, hydrocarbon waxes are more preferred, and Fischer-Tropsch wax is even more preferred.

The content of the wax is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.
In addition, in an endothermic curve during temperature rise measured by a differential scanning calorimetry (DSC) device, the peak temperature of the maximum endothermic peak of the wax is preferably 45° C. or more and 140° C. or less. If the peak temperature of the maximum endothermic peak of the wax is within the above range, it is preferable because it is possible to achieve both storage stability and hot offset resistance of the toner.

The toner according to the present invention may contain a charge control agent as necessary. Any known charge control agent may be used as the charge control agent contained in the toner, but metal compounds of aromatic carboxylic acids are particularly preferred because they are colorless, have a high charging speed, and can stably maintain a constant charge amount.

Negative charge control agents include the following: metal salicylate compounds, metal naphthoate compounds, metal dicarboxylate compounds. Polymeric compounds having sulfonic acid or carboxylic acid on the side chain, polymeric compounds having sulfonate salts or sulfonate esters on the side chain, polymeric compounds having carboxylate salts or carboxylate esters on the side chain. Boron compounds, urea compounds, silicon compounds, calixarenes.

Positive charge control agents include quaternary ammonium salts, polymeric compounds having the quaternary ammonium salts in their side chains, guanidine compounds, and imidazole compounds. Charge control agents may be added internally or externally to the toner particles. The amount of charge control agent added is preferably 0.2 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the binder resin.

The toner according to the present invention may contain other inorganic fine powders as necessary. The inorganic fine powders may be added internally to the toner particles or may be mixed with the toner particles as an external additive. As the external additive, inorganic fine powders such as silica, titanium oxide, and aluminum oxide are preferred. The inorganic fine powders are preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil, or a mixture thereof.

As an external additive for improving fluidity, an inorganic fine powder having a specific surface area of 50 ^m2 /g or more and 400 ^m2 /g or less is preferable, and for stabilizing durability, an inorganic fine powder having a specific surface area of ^{10 m2} /g or more and 50 m2/g or less is preferable. In order to achieve both improvement in fluidity and stabilization of durability, an inorganic fine powder having a specific surface area of ⁵⁰ m2/g or more and 400 m2/g or less and an inorganic fine powder having a specific surface area of ^{10 m2} /g or more and 50 ^m2 /g or less may be used in combination.
The external additive is preferably used in an amount of 0.1 parts by mass to 10.0 parts by mass based on 100 parts by mass of the toner particles. The toner particles and the external additive can be mixed using a known mixer such as a Henschel mixer.

The toner according to the present invention can be used as a one-component developer, but in order to further improve dot reproducibility, it is preferable to mix it with a magnetic carrier and use it as a two-component developer. It is also preferable to use it as a two-component developer from the viewpoint of obtaining stable images over a long period of time.
As the magnetic carrier, for example, a known magnetic material such as the magnetic material described below, or a magnetic material-dispersed resin carrier (so-called resin carrier) containing a magnetic material such as the magnetic material described below and a binder resin that holds the magnetic material in a dispersed state such as the magnetic material described below can be used.
Magnetic material: surface-oxidized or unoxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, and rare earth elements, alloy particles thereof, oxide particles, magnetic materials such as ferrite, etc. When the toner according to the present invention is mixed with a magnetic carrier to be used as a two-component developer, the carrier mixing ratio in this case is preferably 2% by mass or more and 15% by mass or less, more preferably 4% by mass or more and 13% by mass or less, in terms of the toner concentration in the two-component developer. When the toner is in the above range, good results are usually obtained.

The toner particles according to the present invention can be produced by a known method, such as a dry method including a pulverization method, or a wet method including an emulsion aggregation method or a dissolution suspension method.
In either production method, it is preferable to go through a step of mixing the titanium compound containing a carbon atom, the tin compound containing a carbon atom, and the polyester contained in the amorphous polyester.

In the case of the pulverization method, the mixing step can be realized in the step of melt-kneading the polyester.
In the case of the emulsion aggregation method, the mixing step can be realized in the step of preparing a dispersion of fine particles containing a polyester or in the step of heating and fusing aggregated particles.
In the case of the solution suspension method, the mixing step can be realized in the step of preparing a dispersion liquid of the toner material containing the polyester.
Among these, the pulverization method including the step of melt-kneading the polyester is particularly preferred in that it is easy to apply high shear force, and as a result, the titanium compound containing a carbon atom and the tin compound containing a carbon atom can be uniformly dispersed in the polyester, so that the absorption of light of a specific wavelength by coordinate bonds occurs efficiently.

An example of a procedure for producing a toner by the pulverization method will be described below.
In the raw material mixing process, materials constituting the toner particles, such as polyester, and other components such as other resins, wax, colorants, and charge control agents as necessary, are weighed out in predetermined amounts, blended, and mixed. Examples of mixing devices include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a Mechano Hybrid (manufactured by Nippon Coke and Engineering Co., Ltd.).

Next, the mixed materials are melt-kneaded to disperse the wax and the like in the amorphous polyester. The kneading and discharging temperature can be adjusted as appropriate depending on the amorphous polyester used, but is generally preferably 100 to 180°C. In the melt-kneading process, a batch-type kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used, with single-screw or twin-screw extruders being the mainstream due to their advantage of being capable of continuous production.

For example, a KTK type twin screw extruder (manufactured by Kobe Steel, Ltd.), a TEM type twin screw extruder (manufactured by Toshiba Machine Co., Ltd.), a PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.), a twin screw extruder (manufactured by KCK Corporation), a Co-Kneader (manufactured by Buss Co., Ltd.), and a Kneadex (manufactured by Nippon Coke and Engineering Co., Ltd.) can be mentioned. Furthermore, the resin composition obtained by melt kneading can be rolled with two rolls or the like, and cooled with water or the like in a cooling process.

The cooled resin composition is then pulverized to a desired particle size in a pulverization step, which involves, for example, coarse pulverization with a pulverizer such as a crusher, a hammer mill, or a feather mill, followed by further pulverization with a fine pulverizer such as the one described below.
・Miller: Cryptron System (Kawasaki Heavy Industries), Super Rotor (Nisshin Engineering), Turbo Mill (Freund Turbo), or air jet type mill

Thereafter, if necessary, the toner particles are classified using a classifier or sieve as described below to obtain classified products (toner particles).
Classifier or sieve separator: an inertial classification type such as Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), a centrifugal classification type such as Turboplex (manufactured by Hosokawa Micron Corporation), TSP Separator (manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation), etc.
Among these, Faculty (manufactured by Hosokawa Micron Corporation) is preferred in terms of improving transfer efficiency because it can perform a spherical treatment of toner particles simultaneously with classification.

If necessary, after pulverization, the toner particles may be subjected to surface treatment such as spheronization using a surface treatment device as described below.
Surface treatment equipment: Hybridization System (manufactured by Nara Machinery Works), Mechanofusion System (manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation), Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.)

The yellow toner, magenta toner, and cyan toner used in the present invention preferably have a weight average particle size (D4) of 4.0 μm or more and 10.0 μm or less. When the weight average particle size (D4) of each toner is within the above range, the toner has good fluidity, it is easy to obtain a sufficient amount of charge, and it is easier to suppress the occurrence of fog.

From the viewpoint of achieving both improved transferability and cleaning properties, the average circularity of the toner is preferably 0.930 or more and 0.985 or less. When producing toner by a pulverization method, it is preferable to subject the toner particles to a surface treatment such as a spheronization treatment or a heat treatment in order to produce a toner with the above average circularity.

Furthermore, if necessary, an external additive is added to the surface of the toner particles for external addition. As a method for externally adding an external additive, a method is exemplified in which the classified toner and various known external additives are mixed in predetermined amounts and stirred and mixed using a mixer as an external adder as described below.
Mixing equipment: Double Con mixer, V-type mixer, drum type mixer, super mixer, Henschel mixer, Nauta mixer, Mechano Hybrid (manufactured by Nippon Coke & Engineering Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Corporation), etc.

The image forming method according to the present invention is an image forming method having a developing step of developing an electrostatic latent image on an image carrier with toner to form a toner image on the image carrier.
The toners include a yellow toner, a magenta toner and a cyan toner.
Each of the yellow toner, magenta toner and cyan toner contains a resin having a polyester portion and a colorant.
The resin contains 50% by mass or more of the polyester portion.
The yellow toner contains a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by weight per 100 parts by weight of the polyester.
The yellow toner contains a tin compound containing a carbon atom in an amount of 0.005 part by weight or less per 100 parts by weight of the polyester.
Each of the magenta toner and the cyan toner contains a tin compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
Each of the magenta toner and the cyan toner contains 0.005 parts by mass or less of a titanium compound containing a carbon atom per 100 parts by mass of the polyester.

The image forming method for forming a full-color image using the above yellow toner, magenta toner and cyan toner can be realized by devices and means known in the art.
For example, the image forming method of the present invention can be used in an image forming apparatus in which a plurality of developing units are provided for one image carrier.
In addition, the image forming method of the present invention can be used in a tandem type image forming apparatus in which multiple developing devices are installed corresponding to different image carriers, and the toner images formed on each image carrier are transferred sequentially onto a transfer material.
However, the image forming method according to the present invention is not limited to these.

In addition, when the toner image formed on the image carrier is transferred to a transfer material, the image forming method may be such that the toner image is transferred directly from the image carrier to the transfer material. Furthermore, the image forming method may be such that the toner image on the image carrier is primarily transferred to an intermediate transfer material, and the toner image is secondarily transferred from the intermediate transfer material to the transfer material.

The image forming apparatus according to the present invention is an image forming apparatus having an image carrier and a developing means for developing an electrostatic latent image on the image carrier with toner to form a toner image on the image carrier.
The toners include a yellow toner, a magenta toner and a cyan toner.
Each of the yellow toner, magenta toner and cyan toner contains a resin having a polyester portion and a colorant.
The resin contains 50% by mass or more of the polyester portion.
The yellow toner contains a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by weight per 100 parts by weight of the polyester.
The yellow toner contains a tin compound containing a carbon atom in an amount of 0.005 part by weight or less per 100 parts by weight of the polyester.
Each of the magenta toner and the cyan toner contains a tin compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
Each of the magenta toner and the cyan toner contains 0.005 parts by mass or less of a titanium compound containing a carbon atom per 100 parts by mass of the polyester.

The image forming apparatus according to the embodiment of the present invention will be described in detail below with reference to FIG. 1. In this embodiment, a tandem-type full-color printer is described as an example of an image forming apparatus. However, the image forming apparatus according to the present invention is not limited to a tandem-type image forming apparatus, and may be an image forming apparatus of another type. Alternatively, by adding necessary equipment, devices, and housing structures, it can be implemented for various purposes such as printers, various printing machines, copiers, FAX machines, and multifunction machines. In this embodiment, the image forming apparatus 1 has an intermediate transfer belt 44b, and after the toner images of each color are primarily transferred from the photosensitive drum 81 to the intermediate transfer belt 44b, the composite toner images of each color are secondarily transferred collectively to the sheet S. However, the present invention is not limited to this type, and a method of directly transferring from the photosensitive drum to the sheet transported by the sheet transport belt may be adopted.

As shown in FIG. 1, the image forming device 1 includes an image forming device main body (hereinafter referred to as the device main body) 10 as a housing. The device main body 10 includes an image reading unit 11, a sheet feeding unit 30, an image forming unit 40, a sheet transport unit 50, a sheet discharge unit 60, and a control unit 70. A toner image is formed on the surface of a sheet S, which is a recording material. Specific examples of recording materials include plain paper, a resin sheet that is a substitute for plain paper, cardboard, and overhead projector sheets.

The image reading unit 11 is provided on the upper part of the device main body 10. The image reading unit 11 includes a platen glass (not shown) as a document placement platform, a light source (not shown) that irradiates light onto the document placed on the platen glass, an image sensor (not shown) that converts reflected light into a digital signal, and the like.
The sheet feeding unit 30 is located at the bottom of the device main body 10 and is equipped with sheet cassettes 31a, 31b that store sheets S such as plain paper, and feeding rollers 32a, 32b, and feeds the stored sheets S to the image forming unit 40.

The image forming section 40 includes an image forming unit 80, a toner hopper 41, a toner container 42, a laser scanner 43, an intermediate transfer unit 44, a secondary transfer section 45, and a fixing device 46. The image forming section 40 can form an image on a sheet S based on image information. The image forming device 1 of this embodiment is compatible with full color. The image forming units 80y, 80m, 80c, and 80k are provided separately with the same configuration for each of the four colors, yellow (y), magenta (m), cyan (c), and black (k). Similarly, the toner hoppers 41y, 41m, 41c, and 41k and the toner containers 42y, 42m, 42c, and 42k are provided separately with the same configuration for each of the four colors, yellow (y), magenta (m), cyan (c), and black (k). For this reason, in Figure 1, each of the four color configurations is shown with the same reference number followed by a color identifier, but in the specification, they may be described using only the reference number without the color identifier.

The toner container 42 is, for example, a cylindrical bottle that contains toner and is disposed above each image forming unit 80 and connected via a toner hopper 41. The laser scanner 43 exposes the surface of the photosensitive drum 81, which has been charged by the charging roller 82, to form an electrostatic latent image on the surface of the photosensitive drum 81. The charging roller 82 is a roller-shaped charging member.

The image forming unit 80 includes four image forming units 80y, 80m, 80c, and 80k for forming four-color toner images. Each image forming unit 80 includes a photosensitive drum (image carrier) 81 for forming a toner image, a charging roller 82, a developing device 20, and a cleaning blade 84. The photosensitive drum 81, charging roller 82, developing device 20, cleaning blade 84, and developing sleeve 24 (described later) are also provided separately with the same configuration for each of the four colors, yellow (y), magenta (m), cyan (c), and black (k).

The photosensitive drum 81 has a photosensitive layer formed on the outer peripheral surface of an aluminum cylinder so as to have a negative charging polarity, and rotates in the direction of the arrow at a predetermined process speed (circumferential speed). The charging roller 82 contacts the surface of the photosensitive drum 81 and charges the surface of the photosensitive drum 81, for example, to a uniform negative dark potential. After charging, an electrostatic image is formed on the surface of the photosensitive drum 81 by the laser scanner 43 based on image information. The photosensitive drum 81 moves around while carrying the formed electrostatic image, and the image is developed with toner by the developing device 20. The detailed configuration of the developing device 20 will be described later.

The developed toner image is primarily transferred to an intermediate transfer belt 44b, which will be described later. After the primary transfer, the surface of the photosensitive drum 81 is neutralized by a pre-exposure unit (not shown). The cleaning blade 84 is disposed in contact with the surface of the photosensitive drum 81 and cleans off any residual matter, such as transfer residual toner, remaining on the surface of the photosensitive drum 81 after the primary transfer.

The intermediate transfer unit 44 is disposed above the image forming units 80y, 80m, 80c, and 80k. The intermediate transfer unit 44 includes multiple rollers, such as a drive roller 44a, a driven roller 44d, and primary transfer rollers 44y, 44m, 44c, and 44k, and an intermediate transfer belt 44b wound around these rollers. The primary transfer rollers 44y, 44m, 44c, and 44k are disposed opposite the photosensitive drums 81y, 81m, 81c, and 81k, respectively, and come into contact with the intermediate transfer belt 44b.

By applying a positive transfer bias to the intermediate transfer belt 44b by the primary transfer rollers 44y, 44m, 44c, and 44k, the negative toner images on the photosensitive drums 81y, 81m, 81c, and 81k are transferred in sequence to the intermediate transfer belt 44b in a multi-layered manner. As a result, the intermediate transfer belt 44b moves while transferring the toner images obtained by developing the electrostatic images on the surfaces of the photosensitive drums 81y, 81m, 81c, and 81k.

The secondary transfer section 45 includes an inner secondary transfer roller 45a and an outer secondary transfer roller 45b. A positive secondary transfer bias is applied to the outer secondary transfer roller 45b to transfer the full-color image formed on the intermediate transfer belt 44b to the sheet S. The fixing device 46 includes a fixing roller 46a and a pressure roller 46b. As the sheet S is sandwiched and transported between the fixing roller 46a and the pressure roller 46b, the toner image transferred to the sheet S is heated and pressurized to be fixed to the sheet S.

The sheet transport section 50 includes a pre-secondary transfer transport path 51, a pre-fixing transport path 52, a discharge path 53, and a re-conveyance path 54, and transports the sheet S fed from the sheet feeding section 30 from the image forming section 40 to the sheet discharge section 60.
The sheet discharge section 60 includes a pair of discharge rollers 61 arranged downstream of the discharge path 53, and a discharge tray 62 arranged downstream of the pair of discharge rollers 61. The pair of discharge rollers 61 feeds the sheet S conveyed from the discharge path 53 from a nip portion, and discharges the sheet S onto the discharge tray 62 through a discharge port 10a formed in the apparatus main body 10. The discharge tray 62 is a face-down tray, and stacks the sheet S discharged from the discharge port 10a in the direction of the arrow X.

The control unit 70 is configured by a computer and includes, for example, a CPU, a ROM that stores programs that control each unit, a RAM that temporarily stores data, and an input/output circuit that inputs and outputs signals from and to the outside. The CPU is a microprocessor that is responsible for the overall control of the image forming device 1, and is the main system controller. The CPU is connected to the image reading unit 11, the sheet feeding unit 30, the image forming unit 40, the sheet transport unit 50, the sheet discharge unit 60, and the operation unit via the input/output circuit, and exchanges signals with each unit and controls their operation.

The methods for measuring various physical properties of the toner and raw materials will be described below.
<Separation of external additives from toner>
160 g of sucrose (Kishida Chemical) is added to 100 mL of ion-exchanged water, and dissolved in a hot water bath to prepare a high-concentration sucrose solution. 31 g of the high-concentration sucrose solution and 6 mL of Contaminon N (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, with a pH of 7, manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a centrifuge tube to prepare a dispersion. 1.0 g of toner is added to this dispersion, and the toner clumps are loosened with a spatula or the like. Next, the centrifuge tube is shaken with a shaker. After shaking, the solution is transferred to a glass tube (50 mL) for a swing rotor, and separated in a centrifuge at 3500 rpm for 30 min. This operation separates the toner particles from the external additives that have been removed. It is visually confirmed that the toner particles and the aqueous solution are sufficiently separated, and the toner particles are collected and filtered using a vacuum filter, and then dried in a dryer for at least one hour to obtain toner particles from which the external additives have been separated.

<Separation of polyester resin and other resins from toner particles>
By utilizing the difference in solubility in a solvent, the polyester resin and other resins can be separated from the toner particles obtained by the above-mentioned method.

<How to determine the number of parts by mass of resin containing polyester moiety>
The polyester resin solution and the other resin solution obtained by the separation using the difference in solubility in the above-mentioned solvent are used. The mass parts can be calculated from the mass ratio of the solid contents remaining after volatilizing the solvent of these solutions.

<How to determine the number of parts by mass of polyester in polyester resin>
Using the polyester resin solution obtained upon separation utilizing the difference in solubility in the above-mentioned solvent, ¹ H-NMR is carried out under the following conditions.
Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.)
Measurement frequency: 400MHz
Pulse condition: 5.0 μs
Frequency range: 10,500 Hz
Number of measurements: 64 Measurement temperature: 30°C
From the obtained ¹ H-NMR chart, the structure is identified from the peaks attributable to the constituent elements of the monomer unit of the polyester part, and similarly, the structures are identified from the peaks attributable to the constituent elements of the monomer units of the other resins.
From the identified structure, the number of parts by mass of the polyester part in the polyester resin can be determined.

<Method for evaluating the presence or absence of aromatic rings in polyester part>
From the structure identified by the above-mentioned method, the presence or absence of an aromatic ring in the polyester portion can be evaluated.

<Method for measuring the mass parts of titanium compound containing carbon atom or tin compound containing carbon atom contained in toner>
From the residue after separating the polyester resin or other resin, a titanium compound containing a carbon atom or a tin compound containing a carbon atom can be separated. For example, in the case of a magenta toner, a titanium compound containing a carbon atom or a tin compound containing a carbon atom can be separated by dissolving a magenta pigment such as quinacridone or naphthol using N-methyl-2-pyrrolidone or the like. Then, the separated titanium compound or tin compound is measured by ¹ H-NMR under the same conditions as described above.

From the obtained ¹ H-NMR chart, the structure is identified from the peaks attributable to a titanium compound containing a carbon atom, and similarly, the structure is identified from the peaks attributable to a tin compound containing a carbon atom.
From the identified structure, the mass parts of the titanium compound containing carbon atoms or the tin compound containing carbon atoms can be determined.

<Method for measuring the mass parts of titanium atoms in a titanium compound containing a carbon atom or tin atoms in a tin compound containing a carbon atom contained in a toner>
From the structure identified by the above-mentioned method, the parts by mass of titanium atoms in the titanium compound containing carbon atom or tin atoms in the tin compound containing carbon atom contained in the toner can be determined.

<Method for measuring the peak temperature of the maximum endothermic peak of wax>
The peak temperature of the maximum endothermic peak of the wax is measured in accordance with ASTM D3418-82 using a differential scanning calorimeter "Q1000" (manufactured by TA Instruments). The melting points of indium and zinc are used for temperature correction of the detector of the device, and the heat of fusion of indium is used for heat correction.

Specifically, approximately 10 mg of wax is weighed out and placed in an aluminum pan. An empty aluminum pan is used as a reference, and measurements are taken at a temperature rise rate of 10°C/min in the measurement temperature range of 30-200°C. In the measurement, the wax is first heated to 200°C and held there for 10 minutes, then cooled to 30°C, and then heated again. The temperature showing the maximum endothermic peak on the DSC curve in the temperature range of 30-200°C during this second heating process is taken as the peak temperature of the maximum endothermic peak of the wax.

<Measurement of BET specific surface area of inorganic fine powder>
The BET specific surface area of the inorganic fine powder is measured in accordance with JIS Z8830 (2001). The specific measurement method is as follows.
The measuring device used is an "automatic specific surface area and pore distribution measuring device TriStar 3000 (manufactured by Shimadzu Corporation)" that employs a constant volume gas adsorption method as the measuring method. The measurement conditions are set and the measurement data is analyzed using the dedicated software "TriStar 3000 Version 4.00" that comes with this device. A vacuum pump, a nitrogen gas pipe, and a helium gas pipe are connected to this device. The value calculated by the BET multipoint method using nitrogen gas as the adsorption gas is defined as the BET specific surface area of the inorganic fine powder in the present invention.

The BET specific surface area is calculated as follows.
First, nitrogen gas is adsorbed to the inorganic fine powder, and the equilibrium pressure P (Pa) in the sample cell and the nitrogen adsorption amount Va (mol/g) of the external additive are measured. Then, an adsorption isotherm is obtained with the relative pressure Pr, which is the value obtained by dividing the equilibrium pressure P (Pa) in the sample cell by the saturated vapor pressure Po (Pa) of nitrogen, on the horizontal axis and the nitrogen adsorption amount Va (mol/g) on the vertical axis. Next, the monolayer adsorption amount Vm (mol/g), which is the adsorption amount required to form a monolayer on the surface of the external additive, is calculated by applying the following BET formula.
Pr/Va(1-Pr)=1/(Vm×C)+(C-1)×Pr/(Vm×C)
Here, C is a BET parameter, which is a variable that varies depending on the type of measurement sample, the type of adsorption gas, and the adsorption temperature.

The BET equation can be interpreted as a straight line with a slope of (C-1)/(Vm×C) and an intercept of 1/(Vm×C) when the X-axis is Pr and the Y-axis is Pr/Va(1-Pr). This straight line is called a BET plot.
Slope of the line = (C-1) / (Vm x C)
Line intercept = 1/(Vm x C)
If the measured values of Pr and Pr/Va(1-Pr) are plotted on a graph and a line is drawn using the least squares method, the slope and intercept of the line can be calculated. By substituting these values into the above formula and solving the resulting simultaneous equations, Vm and C can be calculated.

Furthermore, the BET specific surface area S (m ² /g) of the inorganic fine powder is calculated from the calculated Vm and the molecular occupancy cross-sectional area of the nitrogen molecule (0.162 nm ² ) according to the following formula.
S=Vm×N×0.162×10-18
where N is Avogadro's number (mol ^-1 ).
Measurements using this device are performed in accordance with the "TriStar 3000 Instruction Manual V4.0" that accompanies the device, and specifically, the measurements are performed in the following procedure.

Accurately weigh the mass of a tared glass sample cell (stem diameter 3/8 inch, volume approximately 5 mL) that has been thoroughly washed and dried. Then, use a funnel to place approximately 0.1 g of the external additive into the sample cell.
The sample cell containing the inorganic fine powder is set in a "pretreatment device VacuPrep 061 (manufactured by Shimadzu Corporation)" connected to a vacuum pump and nitrogen gas piping, and vacuum degassing is continued for about 10 hours at a temperature of 23°C. During vacuum degassing, the valve is adjusted to gradually degas the inorganic fine powder so that it is not sucked into the vacuum pump. The pressure in the sample cell gradually decreases with degassing, and finally becomes about 0.4 Pa (about 3 mTorr). After completion of vacuum degassing, nitrogen gas is gradually injected into the sample cell to return the sample cell to atmospheric pressure, and the sample cell is removed from the pretreatment device. The mass of this sample cell is then precisely weighed, and the exact mass of the external additive is calculated from the difference with the mass of the tare. At this time, the sample cell is covered with a rubber stopper during weighing to prevent the external additive in the sample cell from being contaminated by moisture in the air.

Next, a special "isothermal jacket" is attached to the stem of the sample cell containing the inorganic fine powder. A special filler rod is then inserted into the sample cell, and the sample cell is set in the analysis port of the device. The isothermal jacket is a cylindrical component with a porous inner surface and an impermeable outer surface that is capable of drawing up liquid nitrogen to a certain level by capillary action.

Next, the free space of the sample cell including the connecting device is measured. The free space is calculated by measuring the volume of the sample cell at a temperature of 23°C using helium gas, then measuring the volume of the sample cell after cooling it with liquid nitrogen, also using helium gas, and converting the difference between these volumes. The saturated vapor pressure Po (Pa) of nitrogen is also measured automatically separately using a Po tube built into the device.

Next, the sample cell is evacuated and then cooled with liquid nitrogen while continuing the vacuum evacuation. Nitrogen gas is then gradually introduced into the sample cell to adsorb nitrogen molecules to the inorganic fine powder. At this time, the equilibrium pressure P (Pa) is measured at any time to obtain the adsorption isotherm, which is then converted into a BET plot. The relative pressure Pr points at which data is collected are set to 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30, for a total of six points. A straight line is drawn using the least squares method for the obtained measurement data, and Vm is calculated from the slope and intercept of the straight line. Furthermore, the BET specific surface area of the inorganic fine powder is calculated using this Vm value as described above.

<Weight average particle size (D4) of toner particles>
The weight average particle diameter (D4) of the toner particles is measured with an effective number of measurement channels of 25,000 using the measuring device described below and the accompanying dedicated software described below for setting measurement conditions and analyzing measurement data, and the measurement data is analyzed and calculated.
Measurement device: A precision particle size distribution measurement device using a pore electrical resistance method equipped with a 100 μm aperture tube, "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.)
- Dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter)
The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of about 1 mass %, for example, "ISOTON II" (manufactured by Beckman Coulter, Inc.).
Before carrying out the measurements and analyses, the dedicated software is set up as follows.

In the "Change Standard Measurement Method (SOM) Screen" of the dedicated software, the total count number in the control mode is set to 50,000 particles, the number of measurements is set to 1, and the Kd value is set to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter). The threshold and noise level are automatically set by pressing the threshold/noise level measurement button. In addition, the current is set to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and the aperture tube flush after measurement is checked.
In the "Pulse to particle size conversion setting screen" of the dedicated software, set the bin interval 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 about 200 mL of the electrolyte solution into a 250 mL round-bottom glass beaker for use with the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 rotations per second. Then, remove dirt and air bubbles from inside the aperture tube using the "aperture flush" function of the dedicated software.
(2) About 30 mL of the aqueous electrolyte solution is placed in a 100 mL flat-bottom glass beaker, and about 0.3 mL of a dilution obtained by diluting the Contaminon N three times by mass with ion-exchanged water is added thereto as a dispersant.

(3) A predetermined amount of ion-exchanged water is placed in the water tank of the ultrasonic disperser described below, which has two built-in oscillators with an oscillation frequency of 50 kHz and a phase shift of 180 degrees and an electrical output of 120 W, and about 2 mL of the Contaminon N is added to this water tank.
・Ultrasonic Dispersion System Tetora 150 (manufactured by Nikkaki Bios)
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized.

(5) In a state where the electrolyte solution in the beaker in (4) is irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolyte solution and dispersed. Then, ultrasonic dispersion treatment is continued for another 60 seconds. During ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted so as to be 10°C or higher and 40°C or lower.
(6) The electrolytic solution (5) in which the toner is dispersed is dropped using a pipette into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration is adjusted to about 5%. Then, the measurement is continued until the number of particles measured reaches 50,000.
(7) The measurement data is analyzed using the dedicated software that comes with the device, and the weight-average particle size (D4) is calculated. 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).

The present invention will be specifically explained below with reference to manufacturing examples and working examples, but these are not intended to limit the present invention in any way. Note that all parts and percentages in the following formulations are by weight unless otherwise specified.

<Production Example of Polyester (1)>
Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 71.1 parts by mass (0.20 moles; 100.0 mol% based on the total moles of alcohol components)
Terephthalic acid: 29.9 parts by mass (0.18 moles; 100.0 mol% based on the total number of moles of carboxylic acid components)
Titanyl hydroxytriethanol aminate: 1.000 parts by mass per 100 parts by mass of the total amount of monomer components. The above materials were weighed into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen inlet tube, and a thermocouple. The atmosphere in the flask was then replaced with nitrogen gas, and the temperature was gradually raised while stirring. The mixture was allowed to react for 5 hours at 200°C while stirring to obtain polyester resin (1).

<Production Examples of Polyesters (2) to (34)>
The reaction was carried out in the same manner as in Production Example (1) of Polyester, except that the alcohol component or carboxylic acid component and additives used were changed as shown in Table 1, to obtain polyester resins (2) to (34).

The abbreviations in the table are as follows.
BPA-PO(2.2): Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane

<Production Example of Other Resins (1)>
Solvent: toluene 100.0 parts, styrene 100.0 parts, polymerization initiator t-butyl peroxypivalate (NOF Corp.: Perbutyl PV) 0.5 parts. The above materials were put into a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube under a nitrogen atmosphere. The reaction vessel was heated to 70°C while stirring at 200 rpm to carry out a polymerization reaction for 12 hours, and a solution in which the polymer of the monomer composition was dissolved in toluene was obtained. Subsequently, the temperature of the solution was lowered to 25°C, and the solution was put into 1000.0 parts of methanol while stirring, and the methanol insoluble matter was precipitated. The obtained methanol insoluble matter was filtered off, washed with methanol, and then vacuum dried at 40°C for 24 hours to obtain other resin (1).

<Toner Production Example Y-1>
Polyester resin (1) 100 parts by mass Fischer-Tropsch wax (peak temperature of maximum endothermic peak: 89° C.)
5 parts by weight PY129 (C.I. Pigment Yellow 129) 7 parts by weight 3,5-di-t-butyl salicylic acid aluminum compound 0.5 parts by weight The above materials were mixed using a Henschel mixer (FM-75 type, manufactured by Nippon Coke & Engineering Co., Ltd.) at a rotation speed of 20 s ^-1 and a rotation time of 5 min, and then kneaded at a discharge temperature of 130°C using a twin-screw kneader (PCM-30 type, manufactured by Ikegai Co., Ltd.) set at a temperature of 120°C. The kneaded product obtained was cooled and coarsely crushed to 1 mm or less using a hammer mill to obtain a coarsely crushed product. The obtained coarsely crushed product was finely crushed using a mechanical crusher (T-250, manufactured by Freund Turbo Co., Ltd.). Furthermore, classification was performed using Faculty F-300 (manufactured by Hosokawa Micron Co., Ltd.) to obtain toner particles Y-1. The operating conditions were a classifying rotor rotation speed of 130 s ^-1 and a dispersing rotor rotation speed of 120 s ^-1 .

The following materials were added to 100 parts by mass of the obtained toner particles Y-1, and mixed in a Henschel mixer (FM-75, manufactured by Nippon Coke & Co., Ltd.) at a rotation speed ^{of 30} s for a rotation time of 10 min to obtain toner Y-1. The weight average particle diameter (D4) of toner Y-1 was 6.2 μm.
1.0 part by mass of hydrophobic silica fine particles having a BET specific surface area of 25 m ² /g and surface-treated with 4% by mass of hexamethyldisilazane; 0.8 part by mass of hydrophobic silica fine particles having a BET specific surface area of 100 m ² /g and surface-treated with 10% by mass of polydimethylsiloxane.

(Preparation of Polyester (1) Particle Dispersion)
A mixed solvent of 250 parts by mass of ethyl acetate and 50 parts by mass of isopropyl alcohol was placed in a 5 L separable flask, and 200 parts by mass of polyester (1) was gradually added thereto and stirred with a Three-One Motor (manufactured by Shinto Scientific Co., Ltd.) to dissolve the polyester (1) into an oil phase. An appropriate amount of dilute aqueous ammonia solution was added dropwise to the stirred oil phase, and then 1,000 parts of ion-exchanged water was added dropwise to cause phase inversion emulsification, and the solvent was removed while reducing the pressure with an evaporator to obtain a polyester (1) particle dispersion.

(Preparation of Wax Dispersion)
- Ion-exchanged water 800 parts by mass - Fischer-Tropsch wax (maximum endothermic peak temperature 89°C) 200 parts by mass - Anionic surfactant (Neogen RK: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 10 parts by mass The above was heated to 95°C and thoroughly dispersed using an Ultra-Turrax T50 manufactured by IKA, and then dispersed using a pressure discharge type homogenizer to obtain a wax dispersion having a solid content of 20% by mass.

(Preparation of Colorant Particle Dispersion)
PY180 (C.I. Pigment Yellow 180) 100 parts by weight Sodium dodecylbenzenesulfonate 5 parts by weight Ion-exchanged water 400 parts by weight The above ingredients were mixed and dispersed using a sand grinder mill to obtain a colorant particle dispersion liquid.

<Toner Production Example Y-2>
Polyester (1) particle dispersion 1000 parts by weight Colorant particle dispersion 70 parts by weight Wax dispersion 50 parts by weight Sodium dodecylbenzenesulfonate 5 parts by weight Polyester (1) particle dispersion, wax dispersion and sodium dodecylbenzenesulfonate are placed in a reactor (1 liter flask, anchor blade with baffle) and mixed uniformly. Meanwhile, the colorant particle dispersion is mixed uniformly in a 500 mL beaker, and this is gradually added to the reactor while stirring to obtain a mixed dispersion. 0.5 parts by weight of aluminum sulfate aqueous solution as solids is dropped into the obtained mixed dispersion while stirring to form aggregated particles.
After the dropwise addition was completed, the atmosphere in the system was replaced with nitrogen, and the mixture was maintained at 50° C. for 1 hour and then at 55° C. for 1 hour.

The temperature was then raised to 90° C. and held for 30 minutes. The temperature was then lowered to 63° C. and held for 3 hours to form fused particles. The reaction was carried out in a nitrogen atmosphere. After the specified time had elapsed, the temperature was lowered at a rate of 0.5° C. per minute to room temperature.
After cooling, the reaction product was subjected to solid-liquid separation under a pressure of 0.4 MPa in a 10 L pressure filter to obtain a toner cake. Thereafter, ion-exchanged water was added to the pressure filter until it was filled with water, and the mixture was washed under a pressure of 0.4 MPa. The mixture was washed three times in total in the same manner. The toner cake was dispersed in 1 L of a 50:50 mixed solvent of methanol/water in which 0.15 parts by mass of the following nonionic surfactant 1 was dissolved, to obtain a surface-treated toner particle dispersion.
Nonionic surfactant 1: Polyoxyethylene styrenated phenyl ether (product name: Noigen EA-7 series, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
This toner particle dispersion was poured into a pressure filter, and 5 L of ion-exchanged water was further added thereto. Thereafter, solid-liquid separation was performed under a pressure of 0.4 MPa, and fluidized bed drying was performed at 45° C. to obtain toner particles Y-2.

The following materials were added to 100 parts by mass of the obtained toner particles Y-2, and mixed in a Henschel mixer (FM-75, manufactured by Nippon Coke & Co., Ltd.) at a rotation speed ^{of 30} s for a rotation time of 10 min to obtain toner Y-2. The weight average particle diameter (D4) of toner Y-2 was 6.2 μm.
1.0 part by mass of hydrophobic silica fine particles having a BET specific surface area of 25 m ² /g and surface-treated with 4% by mass of hexamethyldisilazane; 0.8 part by mass of hydrophobic silica fine particles having a BET specific surface area of 100 m ² /g and surface-treated with 10% by mass of polydimethylsiloxane.

<Production Examples of Toners Y-3 to Y-19, M-1 to M-22, C-1 to C-22, and K-1>
Toners Y-3 to Y-19, M-1 to M-22, C-1 to C-22, and K-1 were obtained in the same manner as in the production example of toner Y-1, except that the polyester, other resins, and parts by mass thereof, and the colorant and parts by mass thereof used as raw materials were changed as shown in Table 2.

<Production Example of Magnetic Core Particle 1>
Step 1 (weighing and mixing step):
The ferrite raw _materials were weighed so as to obtain the above composition ratio. Then, the materials were pulverized and mixed for 5 _hours in _a dry vibration mill _using stainless steel beads with a diameter of 1/8 _inch .

Step 2 (pre-firing step):
The obtained pulverized material was made into pellets of about 1 mm square using a roller compactor. The pellets were passed through a vibrating sieve with 3 mm openings to remove coarse powder, and then through a vibrating sieve with 0.5 mm openings to remove fine powder. The pellets were then fired in a burner-type firing furnace at 1000° C. for 4 hours in a nitrogen atmosphere (oxygen concentration 0.01% by volume) to produce calcined ferrite. The composition of the calcined ferrite obtained was as follows:
(MnO)a(MgO)b( _SrO )c( _Fe2O3 )d
In the above formula, a = 0.257, b = 0.117, c = 0.007, d = 0.393

Step 3 (grinding step):
After crushing to about 0.3 mm with a crusher, 30 parts by mass of water was added to 100 parts by mass of the calcined ferrite using zirconia beads with a diameter of 1/8 inch, and the mixture was crushed in a wet ball mill for 1 hour. The slurry was crushed for 4 hours in a wet ball mill using alumina beads with a diameter of 1/16 inch to obtain a ferrite slurry (finely crushed calcined ferrite).

・Process 4 (granulation process):
To the ferrite slurry, 1.0 part by mass of ammonium polycarboxylate as a dispersant and 2.0 parts by mass of polyvinyl alcohol as a binder were added per 100 parts by mass of the calcined ferrite, and the mixture was spun using a spray dryer (manufacturer: Okawara Kakoki). The resulting particles were granulated into spherical particles, and the particle size of the particles was adjusted, and then the particles were heated in a rotary kiln at 650° C. for 2 hours to remove the dispersant and organic components of the binder.

Step 5 (firing step):
In order to control the firing atmosphere, the material was heated from room temperature to 1300° C. in a nitrogen atmosphere (oxygen concentration 1.00% by volume) in an electric furnace over a period of 2 hours, and then fired at a temperature of 1150° C. for 4 hours. The temperature was then lowered to 60° C. over a period of 4 hours, and the material was returned from the nitrogen atmosphere to the air and taken out at a temperature of 40° C. or less.

Step 6 (sorting step):
After crushing the agglomerated particles, low magnetic particles were removed by magnetic separation, and coarse particles were removed by sieving through a sieve with 250 μm openings to obtain magnetic core particles 1 having a volume distribution-based 50% particle size (D50) of 37.0 μm.

<Preparation of Coating Resin 1>
Cyclohexyl methacrylate monomer 26.8% by mass
Methyl methacrylate monomer 0.2% by weight
Methyl methacrylate macromonomer 8.4% by mass
(Macromonomer having a weight average molecular weight of 5000 and a methacryloyl group at one end)
Toluene 31.3% by mass
Methyl ethyl ketone 31.3% by mass
Azobisisobutyronitrile 2.0% by mass

All of the above materials except azobisisobutyronitrile were added to a four-necked separable flask equipped with a reflux condenser, thermometer, nitrogen inlet tube, and stirrer, and nitrogen gas was introduced to create a sufficient nitrogen atmosphere. The mixture was then heated to 80°C, azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours to polymerize. Hexane was injected into the resulting reaction product to precipitate a copolymer, and the precipitate was filtered and then vacuum dried to obtain coating resin 1. The resulting coating resin 1 was dissolved in 30 parts by mass, 40 parts by mass of toluene, and 30 parts by mass of methyl ethyl ketone to obtain polymer solution 1 (solid content 30% by mass).

<Preparation of Coating Resin Solution 1>
Polymer solution 1 (resin solid content concentration 30%) 33.3% by mass
Toluene 66.4% by mass
Carbon black (Regal 330; manufactured by Cabot Corporation) 0.3% by mass
(primary particle size 25 nm, nitrogen adsorption specific surface area 94 ^m2 /g, DBP oil absorption 75 mL/100 g) was dispersed for 1 hour using zirconia beads with a diameter of 0.5 mm in a paint shaker. The resulting dispersion was filtered through a 5.0 μm membrane filter to obtain coating resin solution 1.

<Production Example of Magnetic Carrier 1>
(Resin coating process):
The coating resin solution 1 was added to a vacuum degassing kneader maintained at room temperature so that the resin component was 2.5 parts by mass relative to the filled core particles 1 (100 parts by mass). After addition, the mixture was stirred at a rotation speed of 30 rpm for 15 minutes, and after a certain amount of the solvent (80% by mass) had evaporated, the mixture was heated to 80°C while mixing under reduced pressure, and toluene was distilled off over 2 hours, after which it was cooled. The obtained magnetic carrier was separated into low magnetic products by magnetic separation, passed through a sieve with an opening of 70 μm, and then classified with a wind classifier to obtain a magnetic carrier 1 having a 50% particle size (D50) of 38.2 μm based on the volume distribution.

<Examples 1 to 25 and Comparative Examples 1 to 16>
The combinations shown in Table 3 were used to form toner sets for evaluation.
Each toner and the above-mentioned magnetic carrier 1 were mixed to obtain a two-component developer so that the toner concentration became 8% by mass, and further mixed to obtain a replenishing developer so that the toner concentration became 90% by mass.

As an image forming apparatus, a Canon full-color copier ImagePress C800 was used to form images and perform evaluation. The printing environment was a normal temperature and humidity environment: temperature 23°C/relative humidity 60%. As images for evaluating the chromaticity point, single-color FFh images of yellow, magenta, and cyan were used. In addition, as images for evaluating the color gamut, matching certification/proof equipment/operation certification charts used in the Japan Color certification system were used.
Here, the FFh image is a value that expresses 256 gradations in hexadecimal, with 00h being the first gradation of 256 gradations (white background) and FFh being the 256th gradation of 256 gradations (solid area). The printing was carried out in accordance with the "ISO-compliant Japan Color 2011 for Sheet-fed Offset based on ISO12647-2 Manual". The printing conditions are as follows:

(Printing conditions)
Printing paper: OKtop Coat 128 (manufactured by Oji Paper Co., Ltd.)
Print density: Yellow 1.35, Magenta 1.53, Cyan 1.55, Black 1.70
(Measurement conditions: after drying, status E, black backing, absolute density (including paper white))
The toner amount of each color was adjusted so as to achieve the above print density.

<Evaluation methods and standards for chromaticity points and color gamut of image samples>
The chromaticity points of the image samples for chromaticity point evaluation were evaluated using X-Rite eXact (manufactured by X-Rite Corporation). The colorimetry was performed in accordance with "Japan Color 2011 for Sheet-fed Offset based on ISO12647-2 Manual". The measurement conditions are as follows.

(Measurement condition)
Backing: White backing UV cut filter: None Incident/reflection method: 45/0
Observation light source: D50
Observation conditions: 2 degree viewing angle Lighting standard: M0
Using the above-mentioned device, the chromaticity (L ^* , a ^* , b ^* ) in the L ^* a ^* b ^* color system was measured for each of the colors red, green, and blue. The chroma (C ^* ) was calculated using the following formula based on the measured values of the color characteristics.
C ^* = ((a ^* ) ² + (b ^* ) ² ) ^1/2

Next, ΔE for each secondary color is calculated according to the following formula using C ₀ ^* , L ₀ ^* as the chromaticity points of each secondary color recommended by Japan Color and C _* , L ^* of the prepared image sample for each color.
ΔE=((C ^* _-C0 ^* ) ²⁺ (L ^* _-L0 ^* ) ² ) ^1/2
The smaller the ΔE, the closer each color is to the chromaticity point of Japan Color.
C ₀ ^* and L ₀ ^* for each color are as follows.
Red C ₀ ^* : 82.7, Red L ₀ ^* : 46.3
Green C ₀ ^* : 74.1, Green L ₀ ^* : 47.7
Blue _C0 ^* : 51.7, Blue _L0 ^* : 22.0

<Evaluation criteria for chromaticity points of each color>
A: ΔE≦1.0
B: 1.0<ΔE≦2.0
C: 2.0<ΔE≦3.0
D: 3.0<ΔE≦4.0
E: 4.0<ΔE
Similarly, the images for evaluating the color gamut were measured using the above-mentioned device and measurement conditions. The ratio of the color gamut obtained for each image for evaluating the color gamut to the color gamut of Japan Color was calculated as a percentage and evaluated.

<Japan Color Inclusion Rate Evaluation Criteria>
A: 80% or more B: 76% or more but less than 80% C: 72% or more but less than 76% D: 68% or more but less than 72% E: less than 68% The results of these evaluations are shown in Table 4.

10 Apparatus body 11 Image reading section 20y, 20m, 20c, 20k Developing device 24y, 24m, 24c, 24k Developing sleeve 30 Sheet feeding section 31a, 31b Sheet cassette 32a, 32b Feeding roller 40 Image forming section 41y, 41m, 41c, 41k Toner hopper 42y, 42m, 42c, 42k Toner container 43 Laser scanner 44 Intermediate transfer unit 44a Drive roller 44y, 44m, 44c, 44k Primary transfer roller 44d Driven roller 44b Intermediate transfer belt 45 Secondary transfer section 45a Secondary transfer inner roller 45b Secondary transfer outer roller 46 Fixing device 46a Fixing roller 46b Pressure roller 50 Sheet conveying section 51 Secondary transfer pre-conveying path 52 Pre-conveying path 53 Discharge path 54 Re-conveyance path 60 Sheet discharge section 61 Discharge roller pair 62 Discharge tray 70 Control sections 80y, 80m, 80c, 80k Image forming units 81y, 81m, 81c, 81k Photosensitive drums (image carriers)
82y, 82m, 82c, 82k Charging rollers 84y, 84m, 84c, 84k Cleaning blades

Claims (9)

A color toner set having a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion,
The yellow toner is
a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester;
The polyester resin composition contains a tin compound containing a carbon atom in an amount of 0.005 parts by mass or less per 100 parts by mass of the polyester resin,
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is used in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
A color toner set comprising a titanium compound containing a carbon atom in an amount of 0.005 part by mass or less per 100 parts by mass of said polyester. The color toner set according to claim 1, wherein the resin having the polyester portion is contained in an amount of 80.00 parts by mass or more per 100 parts by mass of the binder resin contained in each of the yellow toner, magenta toner, and cyan toner. The color toner set according to claim 1 or 2, wherein the content of titanium atoms contained in the titanium compound containing a carbon atom is 10.00 to 25.00 parts by mass per 100 parts by mass of the titanium compound containing a carbon atom. The color toner set according to any one of claims 1 to 3, wherein the content of tin atoms contained in the tin compound containing a carbon atom is 18.00 to 51.00 parts by mass per 100 parts by mass of the tin compound containing a carbon atom. The color toner set according to any one of claims 1 to 4, wherein the polyester portion of the resin having the polyester portion has an aromatic ring. The color toner set according to any one of claims 1 to 5, wherein the titanium compound containing a carbon atom contained in the yellow toner is at least one selected from a titanium compound containing an aromatic carboxylate titanium and a titanium compound containing an alcohol amination unit. The color toner set according to any one of claims 1 to 6, wherein the tin compound containing a carbon atom contained in each of the magenta toner and the cyan toner is a tin carboxylate or an alkoxy tin. 1. An image forming method having a developing step of developing an electrostatic latent image on an image carrier with toner to form a toner image on the image carrier,
the toners include a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion,
The yellow toner is
a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester;
The polyester resin composition contains a tin compound containing a carbon atom in an amount of 0.005 parts by mass or less per 100 parts by mass of the polyester resin,
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is used in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
1. An image forming method comprising the steps of: forming a toner containing a titanium compound having a carbon atom in an amount of 0.005 part by mass or less per 100 parts by mass of said polyester; An image forming apparatus having an image carrier and a developing means for developing an electrostatic latent image on the image carrier with a toner to form a toner image on the image carrier,
the toner comprises a yellow toner, a magenta toner and a cyan toner,
Each of the yellow toner, the magenta toner, and the cyan toner contains a resin having a polyester portion and a colorant,
The resin contains 50% by mass or more of the polyester portion,
The yellow toner is
a titanium compound containing a carbon atom in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester;
The polyester resin composition contains a tin compound containing a carbon atom in an amount of 0.005 parts by mass or less per 100 parts by mass of the polyester resin,
Each of the magenta toner and the cyan toner is
A tin compound containing a carbon atom is used in an amount of 0.05 to 2.00 parts by mass per 100 parts by mass of the polyester.
1. An image forming apparatus comprising: a titanium compound containing a carbon atom in an amount of 0.005 part by mass or less per 100 parts by mass of said polyester.

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