JP7471847B2 - Image forming method - Google Patents

Description

The present invention relates to an image forming method such as electrophotography.

Conventionally, in electrophotography, a photoconductive substance is used to form an electrostatic image on a photoreceptor by various means, and then the electrostatic image is developed with a toner. The toner image is transferred to a transfer material such as paper, and then fixed by heating, pressure, heating and pressure, or solvent vapor to obtain an image.
When a multi-color image is obtained by the conventional electrophotographic method, four colors of toner, namely yellow, magenta, cyan, and black, are generally used, and the toner images of each color are superimposed and mixed. Therefore, in printing natural images, multi-color toners are laminated, and the toner layer is often three to four layers, which makes it thick. In addition, in printing characters, etc., the toner layer is thin because it is composed of one to two toner layers. When the toner layer is thin, it is easy to supply thermal energy from a fixing device that applies heat to the entire toner area, but when the toner layer is thick, the surface of the toner layer becomes hot, but the lower layer becomes colder than the surface temperature, and the lower layer toner does not melt sufficiently, resulting in poor fixability. This is because the storage elastic modulus of the four colors of toner used in conventional color image recording devices is the same. This is particularly noticeable in high-speed printing. Therefore, an image forming method has been proposed in which the storage elastic modulus is changed depending on the color to improve fixability (see Patent Documents 1 and 2).
However, according to the inventors' investigations, it was found that there is an image forming method that satisfies the releasability and low-temperature fixability when forming a multi-color toner layer on a transfer material in high-speed printing, while at the same time expanding the color gamut.

Japanese Patent Application Laid-Open No. 6-274002 JP 2014-194528 A

The object of the present invention is to provide an image forming method that has excellent releasability, low-temperature fixing properties, and color gamut when a multi-color toner layer is formed on a transfer material.

The present invention provides an image forming method including a step of forming a composite unfixed toner image on a transfer material, the composite unfixed toner image being formed by superimposing a plurality of toner images, and a fixing step of fixing the composite unfixed toner image on the transfer material by a fixing device which comes into contact with the composite unfixed toner image on the transfer material and applies heat to an upper portion of the composite unfixed toner image,
The toner constituting the toner image has toner particles containing a binder resin, a colorant, and a wax,
the storage modulus G' [Pa] of the toner at 120°C is 5,000≦G'≦30,000;
The image forming method is characterized in that the storage modulus G'(TL) [Pa] of the toner of the uppermost layer constituting the composite unfixed toner image at 150° C. and the storage modulus G'(BL) [Pa] of the toner of the lowermost layer at 110° C. satisfy the relationship 0≦G'(BL)−G'(TL)≦8,000.

According to the present invention, when a multi-color toner layer is formed on a transfer material, an image forming method that has excellent release properties, low-temperature fixing properties, and color gamut can be obtained.

FIG. 10 is an explanatory diagram based on a binarized image of (a) when the organosilicon polymer on the surface of the toner particle has a network structure and (b) when it does not have such a network structure;

In the present invention, the expressions "xx or more and xx or less" or "xx to xx" that express a numerical range refer to a numerical range including the lower and upper limit endpoints, unless otherwise specified.

In the present invention, "(meth)acrylic" means "acrylic" and/or "methacrylic".

The image forming method of the present invention is described in more detail below.

As a result of intensive research aimed at solving the problems of the conventional technology described above, the inventors have discovered that the above problems can be solved by controlling the viscoelastic properties of a toner having toner particles that contain a binder resin, a colorant, and a wax.

That is, the image forming method of the present invention is an image forming method having a step of forming a composite unfixed toner image on a transfer material, in which a plurality of toner images (color toner images) are superimposed, and a fixing step of fixing the composite unfixed toner image on the transfer material by a fixing device that contacts the composite unfixed toner image on the transfer material and applies heat from above the composite unfixed toner image, and is characterized in that the toner (color toner) constituting the toner image has toner particles containing a binder resin, a colorant, and a wax, the storage modulus G' of the toner at 120°C is 5,000≦G'≦30,000, and the storage modulus G'(TL) of the top layer toner constituting the composite unfixed toner image at 150°C and the storage modulus G'(BL) of the bottom layer toner at 110°C satisfy 0≦G'(BL)-G'(TL)≦8,000.

G'(TL) is the storage modulus at 150°C of the toner in the top layer of a composite unfixed toner image formed by superimposing multiple toner images formed on a transfer material.

G'(BL) is the storage modulus at 110°C of the toner in the bottom layer of a composite unfixed toner image formed by superimposing multiple toner images formed on a transfer material.

G'(BL) - G'(TL) represents the difference in storage modulus between the bottom and top layers of toner in a composite unfixed toner image when the composite unfixed toner image is fixed by a fixing device that applies heat from above the toner image. When the difference is between 0 and 8,000, the color gamut of the image is expanded.

Fixing a composite unfixed toner image of multiple colors with excellent low-temperature fixing properties is designed so that the bottom layer melts at a lower temperature than the top layer, so it is difficult to make the difference between G'(BL) and G'(TL) 0 to 8,000. This is particularly noticeable when the storage modulus G' at 120°C is set to 5,000 to 30,000 in order to improve releasability and low-temperature fixing properties.

The inventors' investigations have revealed that when fixing a composite unfixed toner image of multiple colors with excellent low-temperature fixing properties as described above, it is preferable to design the toner so that G' has a minimum value at 110°C or higher and 150°C or lower. By having a minimum value, it becomes easy to design the difference between G'(BL) and G'(TL) to be 0 or higher and 8,000 or lower, and an image with excellent low-temperature fixing properties and a wide color gamut can be obtained.

As an example of a suitable means for obtaining the above-mentioned toner, a method is described below in which the toner particles have a surface layer containing an organosilicon polymer and a styrene-acrylic resin is used as the binder resin. The following is an example, and the means for achieving the above are not limited to this.

The G' of the toner can be controlled by controlling the G' of the binder resin. For example, if the binder resin is a styrene acrylic resin, G' can be controlled by changing the ratio and degree of polymerization of each monomer, organosilicon polymer, etc.

In order to obtain a minimum value for the storage modulus G' at 110°C or higher and 150°C or lower, for example, a surface layer containing an organosilicon polymer may be formed on the surface of the toner particles, and the amount and strength of the organosilicon polymer may be controlled. The strength of the organosilicon polymer may be controlled by changing the type and amount of monomer, reaction temperature, pH, etc., during the process of forming the organosilicon polymer, which will be described later.

It is also preferable that the minimum value of the storage modulus G' at 110°C or higher and 150°C or lower is 1,000 or higher and 20,000 or lower.

Based on the above, the mechanism of action and effect of the present invention is believed to be as follows.

When fixing a composite unfixed toner image of multiple colors with excellent low-temperature fixing properties, if 0≦G'(BL)-G'(TL)≦8,000, the molten toner in the topmost layer and the molten toner in the bottommost layer have similar storage moduli G', and molten materials with similar storage moduli tend to mix easily, expanding the color gamut. In particular, the effect is more easily achieved if the toner has a minimum storage modulus near the fixing temperature.

We will explain each component that makes up the toner and how to manufacture the toner.

<Binder resin>
The toner particles contain a binder resin. The content of the binder resin is preferably 50% by mass or more based on the total amount of the resin components in the toner particles.

There are no particular limitations on the binder resin, but examples include styrene-acrylic resin, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, mixed resins or composite resins thereof. Styrene-acrylic resin and polyester resin are preferred because they are inexpensive, easily available, and have excellent low-temperature fixing properties. Furthermore, it is more preferred to include styrene-acrylic resin because they have excellent development durability.

Polyester resins can be obtained by selecting and combining suitable polycarboxylic acids, polyols, hydroxycarboxylic acids, etc., and synthesizing them using a conventional method such as the ester exchange method or polycondensation method.

Polycarboxylic acids are compounds that contain two or more carboxy groups in one molecule. Of these, dicarboxylic acids are compounds that contain two carboxy groups in one molecule and are preferably used.

For example, oxalic acid, succinic acid, glutaric acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-carboxylic acid, hexahydroterephthalic acid, malonic acid, pimelic acid, suberic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediacetic acid, o-phenylenediacetic acid, diphenylacetic acid, diphenyl-p,p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracenedicarboxylic acid, cyclohexanedicarboxylic acid, etc. can be mentioned.

Examples of polycarboxylic acids other than dicarboxylic acids include trimellitic acid, trimesic acid, pyromellitic acid, naphthalene tricarboxylic acid, naphthalene tetracarboxylic acid, pyrene tricarboxylic acid, pyrene tetracarboxylic acid, itaconic acid, glutaconic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, and n-octenyl succinic acid. These may be used alone or in combination of two or more.

Polyols are compounds that contain two or more hydroxyl groups in one molecule. Of these, diols are compounds that contain two hydroxyl groups in one molecule and are preferably used.

Specifically, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosanedecanediol, diethylene glycol, tridecanediol, tetra ... Examples include polyethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-butenediol, neopentyl glycol, 1,4-cyclohexanediol, polytetramethylene glycol, hydrogenated bisphenol A, bisphenol A, bisphenol F, bisphenol S, and alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts of the above bisphenols.

Among these, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferred, and alkylene oxide adducts of bisphenols and their combination with alkylene glycols having 2 to 12 carbon atoms are particularly preferred.

Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine, sorbitol, trisphenol PA, phenol novolac, cresol novolac, and alkylene oxide adducts of the above trihydric or higher polyphenols. These may be used alone or in combination of two or more.

Examples of styrene-acrylic resins include homopolymers made of the following polymerizable monomers, copolymers obtained by combining two or more of these, and mixtures thereof.

Styrenic monomers such as styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene and p-phenylstyrene;
(meth)acrylic monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, dimethyl phosphate ethyl (meth)acrylate, diethyl phosphate ethyl (meth)acrylate, dibutyl phosphate ethyl (meth)acrylate, and 2-benzoyloxyethyl (meth)acrylate, (meth)acrylonitrile, 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid, and maleic acid;
Vinyl ether monomers such as vinyl methyl ether and vinyl isobutyl ether;
Vinyl ketone monomers such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone;
Polyolefins such as ethylene, propylene, and butadiene.

For the styrene acrylic resin, a polyfunctional polymerizable monomer can be used as necessary. Examples of polyfunctional polymerizable monomers include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2'-bis(4-((meth)acryloxydiethoxy)phenyl)propane, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.

It is also possible to further add known chain transfer agents and polymerization inhibitors to control the degree of polymerization.

Polymerization initiators for obtaining styrene-acrylic resin include organic peroxide initiators and azo polymerization initiators.

Organic peroxide initiators include benzoyl peroxide, lauroyl peroxide, di-α-cumyl peroxide, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, bis(4-t-butylcyclohexyl)peroxydicarbonate, 1,1-bis(t-butylperoxy)cyclododecane, t-butylperoxymaleic acid, bis(t-butylperoxy)isophthalate, methyl ethyl ketone peroxide, tert-butylperoxy-2-ethylhexanoate, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and tert-butylperoxypivalate.

Azo-based polymerization initiators include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobismethylbutyronitrile, and 2,2'-azobis-(methylisobutyrate).

Redox initiators, which combine an oxidizing substance and a reducing substance, can also be used as polymerization initiators.

Oxidizing substances include inorganic peroxides such as hydrogen peroxide, persulfates (sodium, potassium and ammonium salts) and oxidizing metal salts such as tetravalent cerium salts.

Reducing substances include reducing metal salts (divalent iron salts, monovalent copper salts, and trivalent chromium salts), ammonia, lower amines (amines with 1 to 6 carbon atoms, such as methylamine and ethylamine), amino compounds such as hydroxylamine, reducing sulfur compounds such as sodium thiosulfate, sodium hydrosulfite, sodium hydrogensulfite, sodium sulfite, and sodium formaldehyde sulfoxylate, lower alcohols (with 1 to 6 carbon atoms), ascorbic acid or its salts, and lower aldehydes (with 1 to 6 carbon atoms).

Polymerization initiators are selected with reference to their 10-hour half-life temperatures and are used alone or in combination. The amount of polymerization initiator added varies depending on the desired degree of polymerization, but generally 0.5 to 20.0 parts by mass are added per 100.0 parts by mass of polymerizable monomer.

<Wax>
In the toner according to the present invention, known waxes can be used.

Specific examples include petroleum waxes and their derivatives, such as paraffin wax, microcrystalline wax, and petroleum waxes such as petrolactam, montan wax and its derivatives, hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process, polyolefin waxes and their derivatives, such as polyethylene, and natural waxes and their derivatives, such as carnauba wax and candelilla wax. Derivatives also include oxides, block copolymers with vinyl monomers, and graft modified products.

Other examples include alcohols such as higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid or their acid amides, esters, and ketones; hydrogenated castor oil and its derivatives, vegetable waxes, and animal waxes. These can be used alone or in combination.

In terms of phase separation with respect to the binder resin or crystallization temperature, preferred examples include higher fatty acid esters such as behenyl behenate and dibehenyl sebacate.

The wax content is preferably 1.0 to 30.0 parts by mass per 100.0 parts by mass of the binder resin.

The melting point of the wax is preferably 30°C or higher and 120°C or lower, and more preferably 60°C or higher and 100°C or lower.

By using a wax that exhibits the thermal properties described above, the release effect is efficiently achieved and a wider fixing area is ensured.

<Coloring Agent>
The toner particles contain a colorant. Known pigments and dyes can be used as the colorant. Pigments are preferred as the colorant because they have excellent weather resistance.

Cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds.

Specific examples include the following: C.I. Pigment Blue 1, C.I. Pigment Blue 7, C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 60, C.I. Pigment Blue 62, and C.I. Pigment Blue 66.

Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.

Specific examples include the following: C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I. Pigment Violet 19, C.I. Pigment Red 23, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 48:4, C.I. Pigment Red 57:1, C.I. Pigment Red 81:1, C.I. Pigment Red 122, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I. Pigment Red 150, C.I. Pigment Red 166, C.I. Pigment Red 169, C.I. Pigment Red 177, C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 202, C.I. Pigment Red 206, C.I. Pigment Red 220, C.I. Pigment Red 221 and C.I. Pigment Red 254, and C.I. Pigment Violet 19.

Yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

Specific examples include the following: C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I. Pigment Yellow 15, C.I. Pigment Yellow 17, C.I. Pigment Yellow 62, C.I. Pigment Yellow 74, C.I. Pigment Yellow 83, C.I. Pigment Yellow 93, C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 111, C.I. Pigment Yellow 120, C.I. Pigment Yellow 127, C.I. Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 147, C.I. Pigment Yellow 151, C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 168, C.I. Pigment Yellow 174, C.I. Pigment Yellow 175, C.I. Pigment Yellow 176, C.I. Pigment Yellow 180, C.I. Pigment Yellow 181, C.I. Pigment Yellow 185, C.I. Pigment Yellow 191 and C.I. Pigment Yellow 194.

Black colorants include carbon black and those toned to black using the above-mentioned yellow, magenta, and cyan colorants.

These colorants can be used alone or in mixtures, or even in the form of solid solutions.

It is preferable to use 1.0 parts by weight or more and 20.0 parts by weight or less of colorant per 100.0 parts by weight of binder resin.

<Charge Control Agent and Charge Control Resin>
The toner particles may contain a charge control agent or resin.

As the charge control agent, any known charge control agent can be used, and charge control agents that have a high friction charging speed and can stably maintain a constant amount of frictional charge are particularly preferred. Furthermore, when the toner particles are produced by a suspension polymerization method, charge control agents that have low polymerization inhibition properties and are substantially free of solubilized substances in aqueous media are particularly preferred.

There are two types of charge control agents: those that control the toner to be negatively charged and those that control the toner to be positively charged.

Examples of substances that control the toner to be negatively charged include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic and dicarboxylic acid-based metal compounds, aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, phenol derivatives such as bisphenol, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarenes, and charge control resins.

Examples of charge control agents that control the toner to be positively charged include the following:

Guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium 1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts that are analogues of these, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (lake agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, and ferrocyanide); metal salts of higher fatty acids; charge control resins.

Among these charge control agents, metal-containing salicylic acid compounds are preferred, and those in which the metal is aluminum or zirconium are particularly preferred.

The charge control resin may be a polymer or copolymer having a sulfonic acid group, a sulfonate group, or a sulfonate ester group. As a polymer having a sulfonic acid group, a sulfonate group, or a sulfonate ester group, a polymer containing 2% by mass or more of a sulfonic acid group-containing acrylamide monomer or a sulfonic acid group-containing methacrylamide monomer in a copolymerization ratio is particularly preferred, and a polymer containing 5% by mass or more is more preferred.

The charge control resin preferably has a glass transition temperature (Tg) of 35°C or more and 90°C or less, a peak molecular weight (Mp) of 10,000 or more and 30,000 or less, and a weight average molecular weight (Mw) of 25,000 or more and 50,000 or less. When used, it is possible to impart desirable triboelectric charging properties without affecting the thermal properties required for the toner particles. Furthermore, when the charge control resin contains a sulfonic acid group, for example, the dispersibility of the charge control resin itself in the polymerizable monomer composition and the dispersibility of colorants and the like are improved, and the coloring power, transparency, and triboelectric charging properties can be further improved.

These charge control agents or charge control resins may be added alone or in combination of two or more types.

The amount of charge control agent or charge control resin added is preferably 0.01 parts by mass or more and 20.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 10.0 parts by mass or less, per 100.0 parts by mass of binder resin.

<Organosilicon Polymer>
In the present invention, the toner particles preferably have a surface layer containing an organosilicon polymer. Examples of the organosilicon polymer include polymers of organosilicon compounds having a structure represented by the following formula (1).

（式（１）中、Ｒａは、炭素数１以上６以下（好ましくは炭素数１以上３以下）の炭化水素基（好ましくはアルキル基）、又は、アリール基を表し、Ｒ¹、Ｒ²及びＲ³は、それぞれ独立して、ハロゲン原子、ヒドロキシ基、アセトキシ基、又は、（好ましくは炭素数１以上４以下の）アルコキシ基を表す。）

In formula (1), Ra represents a hydrocarbon group (preferably an alkyl group) having 1 to 6 carbon atoms (preferably having 1 to 3 carbon atoms) or an aryl group, and ^R1 , ^R2 , and ^R3 each independently represent a halogen atom, a hydroxyl group, an acetoxy group, or an alkoxy group (preferably having 1 to 4 carbon atoms).

Specific examples of the above formula (1) include the following:

Examples include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrichlorosilane, ethyltriacetoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltrichlorosilane, butyltrimethoxysilane, butyltriethoxysilane, butyltrichlorosilane, butylmethoxydichlorosilane, butylethoxydichlorosilane, hexyltrimethoxysilane, hexyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane. These can be used alone or in combination.

More preferably, the organosilicon polymer has a structure represented by formula (2) below.
R-SiO _3/2 ... (2)

Here, R represents a hydrocarbon group (preferably an alkyl group) having 1 to 6 carbon atoms (preferably 1 to 3 carbon atoms) or an aryl group.

A typical example of the production of organosilicon polymers is a method known as the sol-gel process.

It is generally known that in a sol-gel reaction, the bond state of the siloxane bond generated varies depending on the acidity of the reaction medium. Specifically, when the medium is acidic, a hydrogen ion electrophilically adds to the oxygen of one reactive group (e.g., an alkoxy group; -OR group). Next, an oxygen atom in a water molecule coordinates to a silicon atom, and becomes a hydrosilyl group through a substitution reaction. When there is sufficient water, one H ⁺ attacks one oxygen of a reactive group (e.g., an alkoxy group; -OR group), so when the content of H ⁺ in the medium is low, the substitution reaction to a hydroxyl group is slow. Therefore, a condensation polymerization reaction occurs before all of the reactive groups attached to the silane are hydrolyzed, and one-dimensional linear polymers and two-dimensional polymers are relatively easily generated.

On the other hand, when the medium is alkaline, hydroxide ions are added to silicon via a pentacoordinate intermediate. This makes it easier for all reactive groups (e.g., alkoxy groups; -OR groups) to be eliminated and easily substituted with silanol groups. In particular, when a silicon compound having three or more reactive groups on the same silane is used, hydrolysis and condensation polymerization occur three-dimensionally, forming an organosilicon polymer with many three-dimensional cross-linked bonds. The reaction also finishes in a short time.

The sol-gel method also allows for the creation of a variety of fine structures and shapes, as the material is formed by starting from a solution and gelling the solution. In particular, when the toner particles are produced in an aqueous medium, the hydrophilic properties of hydrophilic groups such as the silanol groups of the organosilicon compound make it easy for them to be present on the surface of the toner particles.

Therefore, to form an organosilicon polymer, it is preferable to carry out the sol-gel reaction in an alkaline reaction medium. When producing in an aqueous medium, it is preferable to carry out the reaction at a pH of 8.0 or higher, at a reaction temperature of 50°C or higher, and for a reaction time of 5 hours or more. This allows the formation of an organosilicon polymer with greater strength and excellent durability.

When observing the surface of a toner particle with a scanning electron microscope, a backscattered electron image of a 1.5 μm square area of the surface of the toner particle is obtained, and a brightness histogram based on the number of pixels is obtained from the backscattered electron image with 256 levels of brightness on the horizontal axis. The histogram has two maximum values P1 and P2, and a minimum value V between P1 and P2, where P2 is the maximum value derived from the organosilicon polymer, the brightness of P1 is 20 to 70, and the brightness of P2 is 130 to 230, the ratio of the number of pixels of P1 and P2 to the total number of pixels of the backscattered electron image is 0.50% or more, and the brightness Vl of the minimum value V is used as the standard, and the total number of pixels with a brightness of 0 or more (Vl-30) or less is defined as A1.

The organosilicon polymer on the toner particle surface preferably forms a network structure on the toner particle surface, with the particles being composed of pixels with a brightness of 0 or more (Vl-30) or less. In scanning electron microscope observation of the toner particle surface, a backscattered electron image of 1.5 μm square on the toner particle surface is obtained, and particles (hereinafter also referred to as particles A1) composed of pixels with a brightness of 0 or more (Vl-30) or less are analyzed. It is preferable that the number average particle area is 2.00×10 ³ nm ² or more and 1.00×10 ⁴ nm ² or less, and the number average particle Feret diameter is 60 nm or more and 200 nm or less. More preferably, the number average particle area is 2.00×10 ³ nm ² or more and 8.00×10 ³ nm ² or less, and the number average particle Feret diameter is 60 nm or more and 150 nm or less.

When the organosilicon polymer on the surface of the toner particle has a network structure, the pixel parts (white) with a brightness between (Vl-29) and 255 form a net, as shown in Figure 1 (a). The particles (particle A1) composed of pixel parts (black) with a brightness between 0 and (Vl-30) where no organosilicon polymer exists form the "mesh" of the network structure and are detected as isolated particles. The detailed method will be described later, but the size of the "mesh" of the network structure can be expressed by performing particle analysis on particle A1 and calculating the particle area and Feret diameter. During fixing, it is from the particle A1 part, which is the parent part of the toner particle, that the binder resin melts and the wax seeps out.

That is, when particle A1 is analyzed, if the particle area and Feret diameter have a certain size, the binder resin melts and the wax oozes out of the base toner particle during fixing. As a result, a toner with excellent low-temperature fixing ability can be obtained. The Feret diameter here is the longest distance among the straight lines connecting any two points on the boundary line of the outer periphery of the selected range. If the particle area is 2.00× ¹⁰³ nm2 ^or more, or the Feret diameter is 60 nm or more, the binder resin melts and the wax oozes out sufficiently, which is advantageous for low-temperature fixing ability, especially from the viewpoint of blisters.

On the other hand, if the particle area is 1.00×10 ⁴ nm ² or less, or the Feret diameter is 200 nm or less, the binder resin melts and the wax seeps out appropriately, which is advantageous for low-temperature fixability, particularly from the viewpoint of hot offset.

The particle area and Feret diameter can be controlled by the type of monomer in the organosilicon polymer, the reaction temperature, reaction time, reaction solvent, and pH during formation of the organosilicon polymer.

The fact that the organosilicon polymer on the surface of the toner particles forms a network structure on the surface of the toner particles, with particles made up of pixels with a brightness of 0 or more (Vl-30) or less, can be confirmed by the following method. When a binarized image is obtained from the backscattered electron image, in which pixel parts with a brightness of 0 or more (Vl-30) or less are colored black, if it has a shape like that shown in Figure 1 (a'), it is determined that the organosilicon polymer has formed a network structure.

On the other hand, as shown in Figure 1(b), when the organosilicon polymer on the surface of the toner particle does not have a network structure, the pixel areas (white) with a brightness between (Vl-29) and 255 are detected as isolated particles. Then, particles A1, which are composed of pixel areas (black) with a brightness between 0 and (Vl-30) where no organosilicon polymer is present, form a network. In other words, when the organosilicon polymer on the surface of the toner particle does not form a network structure, particle analysis of particle A1 tends to reveal larger particle area and Feret diameter.

<Toner Manufacturing Method>
The method for producing the toner particles is not particularly limited, and any known method can be used, with the suspension polymerization method being preferred.

The suspension polymerization method is a method in which particles of a polymerizable monomer composition containing a polymerizable monomer that produces a binder resin, wax, and, if necessary, a colorant, an organosilicon compound, and other additives, are formed in an aqueous medium, and the polymerizable monomer contained in the particles of the polymerizable monomer composition is polymerized to obtain toner particles.

Here, as a first manufacturing method for forming a surface layer of an organosilicon polymer, a method of adding an organosilicon compound to the above-mentioned polymerizable monomer composition can be mentioned. When an organosilicon compound is added, the organosilicon compound is polymerized in a state where it is precipitated near the surface of the toner particles, so that a surface layer containing the organosilicon polymer can be formed on the toner particles. In addition, when this manufacturing method is used, it is easy to precipitate the organosilicon polymer uniformly.

The second manufacturing method is to obtain the base toner particles and then form a surface layer of an organosilicon polymer in an aqueous medium. The base toner particles may be manufactured using a melt-kneading pulverization method, an emulsion aggregation method, a dissolution suspension method, etc.

The aqueous media used in the suspension polymerization method include the following:

Water, alcohols such as methanol, ethanol, propanol, and mixed solvents.

Dispersion stabilizers used when preparing the aqueous medium can be any of the known inorganic and organic compound dispersion stabilizers.

Inorganic dispersion stabilizers include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina.

On the other hand, examples of organic dispersion stabilizers include polyvinyl alcohol, gelatin, methyl cellulose, methylhydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salts, and starch. The amount of these dispersion stabilizers used is preferably 0.2 parts by mass or more and 20.0 parts by mass or less per 100 parts by mass of the polymerizable monomer.

When using an inorganic dispersion stabilizer among these dispersion stabilizers, a commercially available product may be used as is, but in order to obtain a dispersion stabilizer with a finer particle size, the inorganic compound may be produced in an aqueous medium. For example, tricalcium phosphate can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high agitation.

External additives may be added to the obtained toner particles to impart various properties to the toner. Examples of external additives to improve the fluidity of the toner include inorganic fine particles such as silica fine particles, titanium oxide fine particles, and composite oxide fine particles of these. Among the inorganic fine particles, silica fine particles and titanium oxide fine particles are preferred.

Examples of silica fine particles include dry silica or fumed silica produced by vapor-phase oxidation of silicon halides, and wet silica produced from water glass.

Among them, dry silica is preferred because it has fewer silanol groups on the surface and inside the silica particles and less _Na2O and _SO32 ^- .Furthermore, the dry silica may be a composite fine particle of silica and another metal oxide, which is prepared by using a metal halide compound such as aluminum chloride, titanium chloride, etc. together with a silicon halide compound in the manufacturing process.

By subjecting the surfaces of inorganic fine particles to a hydrophobic treatment using a treatment agent, it is possible to adjust the amount of triboelectric charge of the toner, improve environmental stability, and improve fluidity, so it is preferable to use inorganic fine particles that have been hydrophobized.

Examples of treatment agents for hydrophobizing inorganic fine particles include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silicon compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds. Among these, silicone oil is preferred. These treatment agents may be used alone or in combination.

The total amount of inorganic fine particles added is preferably 0.50 parts by mass or more and 5.00 parts by mass or less, and more preferably 1.00 parts by mass or more and 2.50 parts by mass or less, relative to 100 parts by mass of toner particles. From the viewpoint of toner durability, it is preferable that the external additive has a particle size of 1/10 or less of the average particle size of the toner particles.

The following describes how to measure various physical properties in the present invention.

<Measurement of Dynamic Viscoelasticity of Toner>
The measurement device used is a rotating plate type rheometer "ARES" (manufactured by TA INSTRUMENTS, Inc.) The measurement sample used is a sample obtained by pressurizing the toner into a disk shape having a diameter of 7.9 mm and a thickness of 2.0±0.3 mm using a tablet molding machine in an environment of 25° C.

The sample is attached to a parallel plate and heated from room temperature (25°C) to the viscoelasticity measurement starting temperature (50°C), and measurement is started under the following conditions.

The measurement conditions are as follows:
(1) Set the sample so that the initial normal force is 0.
(2) Use a parallel plate with a diameter of 7.9 mm.
(3) The frequency is 1.0 Hz.
(4) The initial applied strain (Strain) is set to 0.1%.
(5) Measurement is performed between 50 and 160° C. at a temperature rise rate (Ramp Rate) of 2.0° C./min and a sampling frequency of 1 time/° C. The measurement is performed under the following automatic adjustment mode setting conditions. The measurement is performed in automatic strain adjustment mode (Auto Strain).
(6) Set the Max Applied Strain to 20.0%.
(7) The maximum torque (Max Allowed Torque) is set to 200.0 g·cm, and the minimum torque (Min Allowed Torque) is set to 0.2 g·cm.
(8) Set the strain adjustment to 20.0% of Current Strain. In the measurement, the automatic tension adjustment mode is used.
(9) Set Auto Tension Direction to Compression.
(10) Set the Initial Static Force to 10.0 g and the Auto Tension Sensitivity to 40.0 g.
(11) The operating condition of the Auto Tension is that the sample modulus is 1.0×10 ³ (Pa) or more.

This measurement makes it possible to determine whether or not there is a minimum value for storage modulus (G') and to determine G'(BL) and G'(TL).

<Method of Obtaining a Reflected Electron Image of the Surface of a Toner Particle>
A backscattered electron image of the surface of the toner particles was obtained by a scanning electron microscope (SEM).

The SEM equipment and observation conditions are as follows.
Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd.
Acceleration voltage: 1.0 kV
WD: 2.0 mm
Aperture Size: 30.0 μm
Detection signal: EsB (energy selective backscattered electrons)
EsB Grid: 800V
Observation magnification: 50,000 times Contrast: 63.0±5.0% (reference value)
Brightness: 38.0±5.0% (reference value)
Resolution: 1024 x 768
Pretreatment: Toner particles are scattered onto carbon tape (no deposition is performed)

The contrast and brightness are determined according to the following procedure. First, the contrast is set so that the two maximum values P1 and P2 on the brightness histogram each have as many pixels as possible, and the brightness of P1 and P2 are as far apart as possible. Next, the brightness is set so that the tails of the two peaks with P1 and P2 as maximum values fall within the brightness histogram. These contrast and brightness are set appropriately according to the state of the device used and according to the above procedure. In addition, the acceleration voltage and EsB Grid of the present invention are set so as to achieve items such as obtaining structural information on the outermost surface of the toner particles, preventing charging up of undeposited samples, and selectively detecting high-energy reflected electrons. The observation field is selected to be near the apex where the curvature of the toner particles is smallest.

<Method for confirming that P2 is derived from an organosilicon polymer>
The fact that P2 is derived from an organosilicon polymer was confirmed by overlaying the backscattered electron image on an element mapping image obtained by energy dispersive X-ray analysis (EDS) that can be obtained with a scanning electron microscope (SEM).

The SEM/EDS equipment and observation conditions are as follows.
Equipment used (SEM): ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd.
Equipment used (EDS): NORAN System 7, Ultra Dry EDS Detector, manufactured by Thermo Fisher Scientific Co., Ltd.
Acceleration voltage: 5.0 kV
WD: 7.0 mm
Aperture Size: 30.0 μm
Detection signal: SE2 (secondary electrons)
Observation magnification: 50,000x Mode: Spectral Imaging
Pretreatment: Toner particles are scattered on carbon tape and platinum sputtered.

The mapping image of silicon element obtained by this method is superimposed on the backscattered electron image, and it is confirmed that the silicon atom part of the mapping image matches the bright part of the backscattered electron image.

<How to obtain a brightness histogram>
The brightness histogram is obtained by analyzing the reflected electron image of the surface of the toner particles obtained by the above-mentioned method using image processing software ImageJ (developed by Wayne Rashand).

First, convert the backscattered electron image to be analyzed to 8-bit from Type in the Image menu. Next, set the Median diameter to 2.0 pixels from Filters in the Process menu to reduce image noise. After excluding the observation condition display section displayed at the bottom of the backscattered electron image, estimate the center of the image and use the Rectangle Tool on the toolbar to select a 1.5 μm square range from the center of the backscattered electron image.

Next, select Histgram from the Analyze menu to display the luminance histogram in a new window. Obtain the luminance histogram values from the List in the window. If necessary, you may perform fitting of the luminance histogram. From this, calculate the luminance and pixel count of the maximum values P1 and P2, the luminance Vl of the minimum value V, and the pixel counts A1, A2, and AV.

The above procedure was carried out for 10 visual fields for the toner particles being evaluated, and the average values for each were used as the physical property values of the toner particles obtained from the brightness histogram.

<Particle analysis method for particle A1>
The particle analysis of the particles A1 was performed by analyzing the reflected electron image of the surface of the toner particles obtained by the above-mentioned method using image processing software ImageJ (developed by Wayne Rashand).

First, convert the backscattered electron image to 8-bit from Type in the Image menu. Next, set the Median diameter to 2.0 pixels from Filters in the Process menu to reduce image noise. After excluding the observation condition display section displayed at the bottom of the backscattered electron image, estimate the center of the image and use the Rectangle Tool on the toolbar to select a 1.5 μm square range from the center of the backscattered electron image.

Next, select Threshold from Adjust in the Image menu. Manually select all pixels with a brightness of 0 or more (V1-30) or less, and click Apply to obtain a binarized image. This operation causes the pixels corresponding to A1 to be displayed in black. Once again, estimate the center of the image after excluding the observation condition display section displayed at the bottom of the backscattered electron image, and use the Rectangle Tool on the toolbar to select a 1.5 μm square range from the center of the backscattered electron image.

Next, use the straight line tool (Straight Line) on the toolbar to select the scale bar in the observation condition display area displayed below the backscattered electron image. In this state, select Set Scale from the Analyze menu to open a new window, and the pixel distance of the selected line is entered in the Distance in Pixels field. Enter the value of the scale bar (e.g., 100) in the Known Distance field of the window, enter the unit of the scale bar (e.g., nm) in the Unit of Measurement field, and click OK to complete the scale setting. Next, select Set Measurements from the Analyze menu, and check Area and Feret's diameter. Select Analyze Particles from the Analyze menu, check Display Result, and click OK to perform particle analysis. From the newly opened Results window, obtain the particle area (Area) and particle Feret diameter (Feret) for each particle that corresponds to A1, and calculate the number average value.

The above procedure was carried out for 10 fields of view for the toner particles to be evaluated, and the average values for each were used as the physical property values of the toner particles obtained from the particle analysis for A1.

<Method for confirming the network structure of organosilicon polymer>
It was confirmed by the following method that the organosilicon polymer on the surface of the toner particles forms a network structure in which particles made up of pixels having a brightness of 0 or more (V1-30) or less are meshed on the surface of the toner particles.

Using the same particle analysis method as for particle A1, a binary image of 1.5 μm square is obtained in which pixel parts with a brightness of 0 or more (V1-30) or less are colored black. If the image has a shape like that shown in Figure 1 (a'), it is determined that the organosilicon polymer has formed a network structure.

<Method of measuring weight average particle size (D4) of toner particles>
The weight average particle size (D4) of the toner particles was calculated by measuring with an effective measurement channel number of 25,000 channels and analyzing the measurement data using a precision particle size distribution measuring device by a pore electrical resistance method "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube and the accompanying dedicated software for setting measurement conditions and analyzing measurement data "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.).

The electrolyte solution used for the measurements is one in which special grade sodium chloride is dissolved in ion-exchanged water to give a concentration of approximately 1% by mass, for example "ISOTON II" (manufactured by Beckman Coulter).

Before performing measurements and analysis, the dedicated software is set 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, the bin interval is set to logarithmic particle size, the particle size bin to 256 particle size bin, 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 revolutions 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 solution prepared by diluting "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, having a pH of 7, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added as a dispersant.
(3) A predetermined amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) having 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.
(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 particles are 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 to be 10°C or higher and 40°C or lower.
(6) Using a pipette, the electrolyte solution (5) in which the toner particles are dispersed is dropped 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).

<Method of confirming the structure represented by formula (2)>
The structure of the organosilicon polymer represented by formula (2) above can be confirmed using a nuclear magnetic resonance (NMR) spectrometer.

The sample for NMR measurement is prepared as follows:

Preparation of measurement sample: 10.0 g of toner particles are weighed out, placed in a cylindrical filter paper (Toyo Roshi No. 86R), placed in a Soxhlet extractor, and extracted for 20 hours using 200 ml of tetrahydrofuran as a solvent. The residue in the cylindrical filter paper is vacuum dried at 40°C for several hours to obtain a sample for NMR measurement.

In the structure represented by formula (2), Ra bonded to a silicon atom is confirmed by ¹³ C-NMR (solid) measurement under the following measurement conditions.

" ^13C -NMR (solid) measurement conditions"
Equipment: JEOL RESONANCE JNM-ECX500II
Sample tube: 3.2 mm diameter
Sample: 150 mg of tetrahydrofuran insoluble matter of toner particles for NMR measurement
Measurement temperature: room temperature Pulse mode: CP/MAS
Measurement nuclear frequency: 123.25MHz ( ^13C )
Reference substance: Adamantane (external standard: 29.5 ppm)
Sample rotation speed: 20 kHz
Contact time: 2 ms
Delay time: 2s
Number of times of accumulation: 1024 times

In formula (2), when R is a structure represented by a hydrocarbon group having 1 to 6 carbon atoms, the presence of R is confirmed by the presence or absence of signals due to groups such as a methyl group (Si-CH ₃ ), an ethyl group (Si-C ₂ H ₅ ), a propyl group (Si-C ₃ H ₇ ), a butyl group (Si-C ₄ H ₉ ), a pentyl group (Si-C ₅ H ₁₁ ), a hexyl group (Si-C ₆ H ₁₃ ), and a phenyl group (Si-C ₆ H ₅ - ) bonded to a silicon atom.

Furthermore, in formula (2), when R is a methine group, an alkylene group, or an arylene group, the presence of R is confirmed by the presence or absence of a signal due to a methine group (>CH-Si), a methylene group (Si-CH ₂ -), an ethylene group (Si-C ₂ H ₄ -), a phenylene group (Si-C ₆ H ₄ -), or the like bonded to a silicon atom.

In the structure represented by formula (2), the siloxane bond portion was confirmed by ²⁹ Si-NMR (solid) measurement under the following measurement conditions.

" ^29Si -NMR (solid) measurement conditions"
Equipment: JEOL RESONANCE JNM-ECX500II
Sample tube: 3.2 mm diameter
Sample: 150 mg of tetrahydrofuran insoluble matter of toner particles for NMR measurement
Measurement temperature: room temperature Pulse mode: CP/MAS
Measurement nuclear frequency: 97.38MHz ( ^29Si )
Reference substance: DSS (external standard: 1.534 ppm)
Sample rotation speed: 10 kHz
Contact time: 10 ms
Delay time: 2s
Number of times: 2000 to 8000

After the above measurement, the peaks of a plurality of silane components having different substituents and bonding groups in the tetrahydrofuran insoluble portion of the toner particles are separated into the following X1 structure, X2 structure, X3 structure, and X4 structure by curve fitting, and the peak areas of each are calculated.
X1 structure represented by formula (3): (Ri) (Rj) (Rk) SiO _1/2
X2 structure represented by formula (4): (Rg)(Rh)Si(O1 _/2 ) ₂
X3 structure represented by formula (5): RmSi(O1 _/2 ) ₃
X4 structure represented by formula (6): Si(O1 _/2 ) ₄

（式（３）～（６）中のＲｉ、Ｒｊ、Ｒｋ、Ｒｇ、Ｒｈ、Ｒｍは、上記のＲと同一の有機基、ハロゲン原子、ヒドロキシ基、アセトキシ基又はアルコキシ基を示す。）

(In formulas (3) to (6), Ri, Rj, Rk, Rg, Rh, and Rm each represent an organic group, a halogen atom, a hydroxyl group, an acetoxy group, or an alkoxy group, which are the same as those represented by R above.)

In formulas (3) to (6), the structures enclosed by squares are X1 to X4 structures, respectively.

In a chart obtained by measuring the tetrahydrofuran insoluble matter of the toner by ²⁹ Si-NMR, the ratio of the peak area attributable to the structure of formula (2) to the total peak area of the organosilicon polymer is preferably 20% or more and 100% or less.

When it is necessary to confirm the structure represented by formula (2) in more detail, it may be identified by the results of ¹ H-NMR measurement in addition to the results of ¹³ C-NMR and ²⁹ Si-NMR measurement.

The present invention will be explained in detail with reference to the following examples. However, these are not intended to limit the present invention in any way. Note that all parts in the examples and comparative examples are by weight unless otherwise specified.

<Production Example of Polyester Resin>
Terephthalic acid 15.00 parts Isophthalic acid 15.00 parts Bisphenol A-propylene oxide 2 mole adduct 70.00 parts Potassium oxalate titanate 0.03 parts In an autoclave equipped with a pressure reducing device, a water separating device, a nitrogen gas introducing device, a temperature measuring device, and a stirring device, the above components were charged and reacted at 220 ° C. for 17 hours under a nitrogen atmosphere, and further reacted for 0.5 hours under a reduced pressure of 10 to 20 mmHg. Thereafter, the temperature was lowered to 180 ° C., 0.10 parts of trimellitic anhydride was added, and the reaction was carried out at 175 ° C. for 2.0 hours to obtain a polyester resin. The weight average molecular weight (Mw) of the obtained polyester resin was 9,500, the glass transition temperature (Tg) was 73 ° C., and the acid value (Av) was 8.0 mg KOH / g.

<Production Example of Yellow Toner 1>
5.0 parts of C.I. Pigment Yellow 155 and 1.0 part of a charge control agent (Bontron E88; manufactured by Orient Chemical Industry Co., Ltd.) were prepared relative to 60.0 parts of styrene. These were introduced into an attritor (manufactured by Mitsui Mining Co., Ltd.) and stirred at 200 rpm at 25°C for 180 minutes using zirconia beads with a radius of 1.25 mm to prepare a pigment dispersion composition.

60.0 parts of ion-exchanged water was weighed into a reaction vessel equipped with a stirrer and thermometer, and the pH was adjusted to 3.0 using 10% by weight hydrochloric acid. This was heated with stirring until the temperature reached 70°C. 40.0 parts of methyltriethoxysilane, an organosilicon compound for the surface layer, was then added and stirred for at least 2 hours to carry out hydrolysis. The end point of hydrolysis was confirmed by visual inspection when the oil and water did not separate and formed a single layer, and the mixture was cooled to obtain a hydrolyzed liquid of the organosilicon compound for the surface layer.

Meanwhile, 900 parts of ion-exchanged water heated to 60°C and 2.5 parts of tricalcium phosphate were added to a separate container, and the mixture was stirred at 10,000 rpm using a T.K. homomixer (manufactured by Tokushu Kika Kogyo) to obtain an aqueous medium.

The following materials were mixed and dispersed at 5000 rpm using a T. K. Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).
Pigment dispersion composition 66.0 parts Styrene 15.0 parts n-butyl acrylate 25.0 parts Polyester resin 5.0 parts Divinylbenzene (crosslinking agent) 0.60 parts Further, after heating to 60°C, 10.0 parts of behenyl behenate, 5.0 parts of hydrocarbon wax (HNP-9; manufactured by Nippon Seiro Co., Ltd.), and 2.00 parts of Perbutyl D (manufactured by Nippon Oil & Fats Co., Ltd.) were added and dispersed and mixed for 30 minutes, and 10.0 parts of the polymerization initiator 2,2'-azobis(2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition was added to the aqueous medium and stirred at 10,000 rpm for 10 minutes in a T.K. homomixer at 60°C under a nitrogen atmosphere to granulate the polymerizable monomer composition, and then heated to 70°C while stirring with a paddle impeller. After reacting for 5 hours, the temperature was further raised to 85°C and reacted for 2 hours to obtain toner base 1. At this time, the pH of the aqueous medium was 5.1.

Next, the internal temperature was set to 55°C, and 20.0 parts of hydrolyzed solution of the organic silicon compound for the surface layer was added to start the formation of the toner surface layer. After holding for 30 minutes, the slurry was adjusted to pH = 9.0 using an aqueous sodium hydroxide solution to complete the condensation, and held for another 300 minutes to form the surface layer. After cooling to 30°C, 10% hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 2 hours. The toner particles were filtered, washed with water, and then dried at a temperature of 40°C for 48 hours to obtain yellow toner particles 1. The obtained yellow toner particles 1 are referred to as yellow toner 1. The weight average particle size (D4) of yellow toner 1 was measured using a Coulter Counter Multisizer 3 (manufactured by Beckman Coulter, Inc.) and found to be 6.2 μm. Other physical properties are shown in Table 2.

<Production Example of Magenta Toner 1>
Magenta toner 1 was produced in the same manner as in the production example of yellow toner 1, except that the pigments added in the production example of yellow toner 1 were changed to 3.0 parts of C.I. Pigment Red 122 and 2.0 parts of C.I. Pigment Red 150.

<Production Example of Cyan Toner 1>
Cyan toner 1 was produced in the same manner as in the production example of yellow toner 1, except that the pigment added in the production example of yellow toner 1 was changed to 5.0 parts of C.I. Pigment Blue 15:3.

<Production Examples of Yellow Toners 2 to 13, Magenta Toners 2 to 5, and Cyan Toners 2 to 12>
Yellow toners 2 to 13, magenta toners 2 to 5, and cyan toners 2 to 12 were produced in the same manner as in the production examples of yellow toner 1, magenta toner 1, and cyan toner 1, except that in the production examples of yellow toner 1, magenta toner 1, and cyan toner 1, the type and amount of wax added, the amount of crosslinking agent, the type of organosilicon compound, the preparation conditions, and the number of parts added were changed to the compositions shown in Table 1.

Example 1
An LBP9600C (Canon) was used as an evaluation machine, and the yellow cartridge was refilled with yellow toner 1, and the magenta cartridge was refilled with magenta toner 2. Evaluations were made on hot offset resistance, blister resistance, and color gamut in a normal temperature and humidity environment (25° C., 50% RH). In the evaluation machine, when two color toners, yellow and magenta, are superimposed on a transfer material, the toner closest to the fixing device becomes the yellow toner, and the toner closest to the transfer material becomes the magenta toner. The evaluation results are shown in Table 3. The print speed of the evaluation machine is A4: 30 sheets/min.

(1) Blister Resistance Xerox Business 4200 (basis weight 105 g/ ^m2 ) was used as the evaluation paper. An image with an area of 5 cm x 5 cm was printed with a toner amount of 0.80 mg/ ^cm2 (yellow toner 1 0.40 mg/ ^cm2 , magenta toner 2 0.40 mg/ ^cm2 ). While changing the fixing temperature, the images printed at each temperature were visually checked for the occurrence of blisters, and were evaluated based on the following evaluation criteria.
A: The temperature at which the heat is generated is less than 160°C. B: The temperature at which the heat is generated is 160°C or more and less than 170°C. C: The temperature at which the heat is generated is 170°C or more and less than 180°C. D: The temperature at which the heat is generated is 180°C or more.

(2) Hot offset resistance: Canon's Office 70 (basis weight 70 g/ ^m2 ) was used as the evaluation paper, and an image with an area of 2 cm x 2 cm was printed with a toner amount of 0.80 mg/ ^cm2 (yellow toner 1: 0.40 mg/ ^cm2 , magenta toner 2: 0.40 mg/ ^cm2 ). While changing the fixing temperature, the fixing temperature was confirmed at the time when hot offset occurred at the rear end of the evaluation paper in the paper passing direction when it passed through the fixing device, and the evaluation was made based on the following evaluation criteria.
A: The temperature at which the heat is generated is 210°C or higher. B: The temperature at which the heat is generated is 200°C or higher but less than 210°C. C: The temperature at which the heat is generated is 190°C or higher but less than 200°C. D: The temperature at which the heat is generated is less than 190°C.

(3) Evaluation of color gamut Canon GF-C081 paper (basis weight 81.4 g/ ^m2 ) was used as the evaluation paper, and an image pattern in which nine square images with an area of 10 mm x 10 mm were evenly arranged on the paper was printed on seven sheets with toner amounts ranging from 0.20 mg/ ^cm2 to 0.80 mg/ ^cm2 (equal amounts of yellow toner 1 and magenta toner 2) in increments of 0.10 mg/ ^cm2 , and fixed at a fixing temperature of 150°C.

The saturation (C ^* ) of a 10 mm x 10 mm square image was measured using a "Spectrolino" (manufactured by Macbeth) in accordance with the attached instruction manual. The saturation of the nine points obtained was averaged to obtain the saturation value. The saturation of seven images was measured, and the highest saturation obtained was evaluated according to the following index.
A: Saturation is 84 or more. B: Saturation is 81 or more and less than 84. C: Saturation is 78 or more and less than 81. D: Saturation is less than 78.

[Examples 2 to 26, Comparative Examples 1 to 5]
Using the toners shown in Table 3, the same evaluation as in Example 1 was carried out. The evaluation results are shown in Table 3.

Claims (7)

1. An image forming method comprising: a step of forming a composite unfixed toner image on a transfer material, the composite unfixed toner image being formed by superimposing a plurality of toner images; and a fixing step of fixing the composite unfixed toner image on the transfer material by a fixing device which comes into contact with the composite unfixed toner image on the transfer material and applies heat to an upper portion of the composite unfixed toner image,
The toner constituting the toner image has toner particles containing a binder resin, a colorant, and a wax,
the storage modulus G' [Pa] of the toner at 120°C is 5,000≦G'≦30,000;
The image forming method is characterized in that the storage modulus G'(TL) [Pa] of the toner of the uppermost layer constituting the composite unfixed toner image at 150°C and the storage modulus G'(BL) [Pa] of the toner of the lowermost layer at 110°C satisfy 0≦G'(BL)-G'(TL)≦8,000. The image forming method according to claim 1, wherein the toner has a minimum storage modulus G' in the range of 110°C to 150°C. 3. The image forming method according to claim 1, wherein the toner has a minimum storage modulus G' [Pa] in the range of 110° C. to 150° C., which satisfies 1,000≦G'≦20,000. The image forming method according to any one of claims 1 to 3, wherein the toner particles have a surface layer containing an organosilicon polymer. The image forming method according to claim 4, wherein the toner particles have an organosilicon polymer network on the surface. When the surface of the toner particle is observed with a scanning electron microscope, a backscattered electron image of a 1.5 μm square area of the surface of the toner particle is obtained, and a luminance histogram based on the number of pixels with 256 gradation luminance levels plotted on the horizontal axis is obtained from the backscattered electron image. The histogram has two maximum values P1 and P2 and a minimum value V between P1 and P2, P2 being the maximum value derived from the organosilicon polymer, and the luminance of the minimum value V is designated as Vl. When particle analysis is performed on the total number of pixels with a luminance of 0 or more (Vl-30) or less,
6. The image forming method according to claim 4, wherein the number-average particle area is from 2.00×10 ³ nm ² to 1.00×10 ⁴ nm ² , and the number-average particle Feret diameter is from 60 nm to 200 nm. 1. An image forming method comprising: a step of forming a composite unfixed toner image on a transfer material, the composite unfixed toner image being formed by superimposing a plurality of color toner images; and a fixing step of fixing the composite unfixed toner image on the transfer material by a fixing device which comes into contact with the composite unfixed toner image on the transfer material and applies heat to an upper portion of the composite unfixed toner image,
The toner constituting the color toner image has toner particles containing a binder resin, a colorant, and a wax,
the storage modulus G' [Pa] of the toner at 120°C is 5,000≦G'≦30,000;
The image forming method is characterized in that the storage modulus G'(TL) [Pa] of the color toner of the uppermost layer constituting the composite unfixed toner image at 150°C and the storage modulus G'(BL) [Pa] of the color toner of the lowermost layer at 110°C satisfy 0≦G'(BL)-G'(TL)≦8,000.

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