JP2020190715A - White toner - Google Patents

Abstract

To provide a white toner that is excellent in concealability as a white toner and also excellent in folding resistance and low-temperature fixability.SOLUTION: A toner has toner particles containing a binder resin and a white pigment. The toner particle contains the white pigment in an amount of 20 mass% or more and 80 mass% or less. The binder resin contains a polymer A having a first monomer unit having a specific structure and a second monomer unit different therefrom. The content ratio of the first monomer unit in the polymer A is 5.0 mol% to 60.0 mol% based on the total mol number of all the monomer units in the polymer A. The content ratio of the second monomer unit in the polymer A is 20.0 mol% to 95.0 mol% based on the total mol number of all the monomer units in the polymer A. The SP values of the first monomer unit and the second monomer unit satisfy a specific relational expression. The total amount of the surface acidic group amount and the surface basic group amount of the white pigment is 60 μmol/g or more.SELECTED DRAWING: None

Description

The present invention relates to a white toner used in an electrophotographic image forming method.

In recent years, with the development of image forming devices such as copiers and printers, toner capable of supporting various media is required. Among them, a technique for obtaining a high-value-added printed matter by using a special color toner such as a transparent toner or a white toner has been developed.
White toner is important for forming a white image on colored paper or transparent film, and in order to achieve high hiding power, toner using a material having a high refractive index such as titanium oxide has been developed. (Patent Document 1). Further, a white toner using a crystalline resin has been developed (Patent Document 2).

Japanese Unexamined Patent Publication No. 2000-56514 Japanese Unexamined Patent Publication No. 2012-177763

Usually, in order to form a white image using white toner and express sufficient white color, it is preferable to conceal the underlying color so that it cannot be recognized. Since such image hiding properties are exhibited by scattering light in the image film, the pigment itself is colorless and the difference in refractive index from the binder resin is large, that is, a material having a high refractive index is used. Desired. Further, in the white toner, in order to exhibit sufficient hiding power, it is preferable that the white pigment as described above is contained in the toner in a large amount and with good dispersibility as compared with other colors.

However, when a large amount of white pigment such as titanium oxide is contained in the toner, the bending resistance of the fixed image becomes poor due to the increase in the interface between the binding resin having low interaction and the white pigment. It turned out that it may decrease. To solve this problem, the bending resistance can be improved by using a high molecular weight resin having a large amount of cross-linking components. However, since the viscosity of the toner becomes high, there is a problem that the low temperature fixability becomes insufficient.
Further, even when a crystalline resin is used, although it contributes to low-temperature fixability, the image intensity may be insufficient.
In response to such a problem, an object of the present invention is to provide a white toner which is excellent in concealing property as a white toner and also excellent in bending resistance and low temperature fixability.

As a result of diligent studies by the present inventors, a resin having a specific structure in the toner particles and a white pigment having an acid-base amount (total amount of surface acidic group amount and surface basic group amount) of 60 μmol / g or more have been obtained. It has been found that the above-mentioned problems can be solved by containing the mixture.
That is, according to one aspect of the present invention.
A toner having toner particles containing a binder resin and a white pigment.
The toner particles contain the white pigment in an amount of 20% by mass or more and 80% by mass or less.
The binder resin contains a first monomer unit represented by the following formula (A-1) and a polymer A having a second monomer unit different from the first monomer unit.

(In the formula (A-1), R ₁ represents an alkyl group having 18 to 36 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group.)
The content ratio of the first monomer unit in the polymer A is 5.0 mol% to 60.0 mol% based on the total number of moles of all the monomer units in the polymer A.
The content ratio of the second monomer unit in the polymer A is 20.0 mol% to 95.0 mol% based on the total number of moles of all the monomer units in the polymer A.
When the SP value of the first monomer unit is SP ₁₁ (J / cm ³ ) ^0.5 and the SP value of the second monomer unit is SP ₂₁ (J / cm ³ ) ^0.5 , the SP ₁₁ and the SP ₂₁ satisfy the following equations (1) and (2).
3.00 ≤ (SP _21- SP ₁₁ ) ≤ 25.00 ... (1)
21.00 ≤ SP ₂₁ ... (2)
Provided is a white toner characterized in that the total amount of the surface acidic group amount and the surface basic group amount of the white pigment is 60 μmol / g or more.

Further, according to another aspect of the present invention.
A toner having toner particles containing a binder resin and a white pigment.
The toner particles contain the white pigment in an amount of 20% by mass or more and 80% by mass or less.
The binder resin contains a polymer B of a composition containing a first polymerizable monomer and a second polymerizable monomer different from the first polymerizable monomer.
The first polymerizable monomer is represented by the following formula (A-2).

(In the formula (A-2), R ₁ represents an alkyl group having 18 to 36 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group.)
The content of the first polymerizable monomer in the composition is 5.0 mol% to 60.0 mol% with respect to the total number of moles of the total polymerizable monomers in the composition. ,
The content of the second polymerizable monomer in the composition is 20.0 mol% to 95.0 mol% with respect to the total number of moles of the total polymerizable monomer in the composition. ,
The SP value of the first polymerizable monomer is SP ₁₂ (J / cm ³ ) ^0.5, and the SP value of the second polymerizable monomer is SP ₂₂ (J / cm ³ ) ^0.5. Then, the SP ₁₂ and the SP ₂₂ satisfy the following formula (3) and the following formula (4).
0.60 ≦ (SP ₂₂ −SP ₁₂ ) ≦ 15.00 ・ ・ ・ (3)
18.30 ≤ SP ₂₂ ... (4)
Provided is a white toner characterized in that the total amount of the surface acidic group amount and the surface basic group amount of the white pigment is 60 μmol / g or more.

According to the present invention, it is possible to provide a white toner which is excellent in concealing property as a white toner, and is also excellent in bending resistance and low temperature fixability.

In the present invention, the description of "○○ or more and XX or less" and "○○ to XX" indicating a numerical range means a numerical range including a lower limit and an upper limit which are end points, unless otherwise specified.
In the present invention, the (meth) acrylic acid ester means an acrylic acid ester and / or a methacrylic acid ester.
In the present invention, the "monomer unit" is defined as one unit of one carbon-carbon bond section in the main chain in which the vinyl-based monomer in the polymer is polymerized. The vinyl-based monomer can be represented by the following formula (Z).

[In formula (Z), R _Z1 represents a hydrogen atom or an alkyl group, and R _Z2 represents an arbitrary substituent. ]

The present inventors consider the mechanism by which the effects of the present invention are exhibited as follows.
The polymer A contained in the toner has the following formula (A-1):

(In the formula (A-1), R ₁ represents an alkyl group having 18 to 36 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group.)
It has a first monomer unit represented by and a second monomer unit different from the first monomer unit, and those monomer units have a predetermined SP value difference, so that a phase-separated state is formed without compatibility. .. The second monomer unit has an SP value of 21.00 (J / cm ³ ) of ^0.5 or more. When such a second monomer unit and a white pigment having a total amount of surface acidic groups and surface basic groups of 60 μmol / g or more are combined, both are hydrophilic and have high affinity. Therefore, the second monomer unit is unevenly distributed on the surface of the white pigment inside the toner. On the other hand, since the first monomer unit has a long-chain alkyl portion, it is easy to form a crystal structure. A region in which the second monomer unit is unevenly distributed and a crystal region formed by the first monomer unit are formed between the white pigment particles. As a result, it is presumed that the strength of the entire fixing film is improved and the bending resistance of the fixed image is improved.
It is presumed that the effect of the invention is exhibited by the same mechanism when the polymer B is used instead of the polymer A.
The details of the present invention will be described below.

<Polymer A / Polymer B>
In the first embodiment, the white toner contains a first monomer unit represented by the above formula (A-1) and a polymer A having a second monomer unit different from the first monomer unit. ..

Further, when the SP value of the first monomer unit is SP ₁₁ (J / cm ³ ) ^0.5 and the SP value of the second monomer unit is SP ₂₁ (J / cm ³ ) ^0.5 , SP ₁₁ And SP ₂₁ satisfy the following equations (1) and (2).
3.00 ≤ (SP _21- SP ₁₁ ) ≤ 25.00 ... (1)
21.00 ≤ SP ₂₁ ... (2)

Further, in the second aspect, the white toner of the present invention is different from the first polymerizable monomer represented by the following formula (A-2) and the first polymerizable monomer. Contains a polymer (polymer B) of the composition containing the polymerizable monomer of.

(In the formula (A-2), R ₁ represents an alkyl group having 18 to 36 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group.)
The SP value of the first polymerizable monomer is SP ₁₂ (J / cm ³ ) ^0.5, and the SP value of the second polymerizable monomer is SP ₂₂ (J / cm ³ ) ^0.5. Then, SP ₁₂ and SP ₂₂ satisfy the following formula (3) and the following formula (4).
0.60 ≦ (SP ₂₂ −SP ₁₂ ) ≦ 15.00 ・ ・ ・ (3)
18.30 ≤ SP ₂₂ ... (4)

Since the first monomer unit contained in the polymer A has an alkyl group having 18 to 36 carbon atoms, the polymer A becomes crystalline and the low temperature fixability is improved. Further, since the crystal sites continuously form a network structure between the white pigments, the fixing film strength after fixing is improved, and the bending resistance is improved.

The unit of the SP value in the present invention is (J / m ³ ) ^0.5 , but by 1 (cal / cm ³ ) ^0.5 = 2.045 × 10 ³ (J / m ³ ) ^0.5 ( cal / cm ³ ) Can be converted to a unit of ^0.5 .
By satisfying the SP value difference defined by the formula (1) or the formula (3), the decrease in crystallinity of the polymer A or the polymer B can be suppressed. As a result, both low-temperature fixability and heat-resistant storage stability can be achieved, which is preferable.

In the first embodiment, the content ratio of the first monomer unit in the polymer A is 5.0 mol% to 60.0 mol% based on the total number of moles of all the monomer units in the polymer A. The content ratio of the second monomer unit in the polymer A is 20.0 mol% to 95.0 mol% based on the total number of moles of all the monomer units in the polymer A.
Further, in the second embodiment, the content of the first polymerizable monomer is 5.0 mol% to 60.0 mol% with respect to the total number of moles of the total polymerizable monomers in the composition. Is. The content of the second polymerizable monomer is 20.0 mol% to 95.0 mol% with respect to the total number of moles of the total polymerizable monomer in the composition.

When the content ratio of the first monomer unit and the content ratio of the first polymerizable monomer are within the above ranges, sharp melt property is exhibited and excellent low temperature fixability can be obtained. In addition, the crystal network becomes appropriate, and good bending resistance can be obtained.

The polymerizable monomer producing the first monomer unit in the first embodiment (the same applies to the first polymerizable monomer in the second embodiment) is a (meth) acrylic having an alkyl group having 18 to 36 carbon atoms. Selected from the group consisting of acid esters.
Examples of the polymerizable monomer include the following.
Stearyl (meth) acrylate, nonadesyl (meth) acrylate, eicosyl (meth) acrylate, heneicosanyl (meth) acrylate, behenyl (meth) acrylate, lignoceryl (meth) acrylate, ceryl (meth) acrylate, (meth) (Meta) acrylic acid ester having a linear alkyl group with 18 to 36 carbon atoms such as octacosa acrylate, myricyl (meth) acrylate, dodria contour (meth) acrylate; 2-decyl (meth) acrylate. A (meth) acrylic acid ester having a branched alkyl group having 18 to 36 carbon atoms, such as tetradecyl.
These polymerizable monomers may be used alone or in combination of two or more.

As the second polymerizable monomer forming the second monomer unit, for example, the following polymerizable monomer can be used. The second polymerizable monomer may be used alone or in combination of two or more.
・ Monomer having a nitrile group,
・ Monomer having a hydroxy group,
・ Monomer having an amide group,
・ Vinyl esters,
・ Monomer with urethane group,
・ Monomer with urea group,
-A monomer having a carboxy group.

Examples of the monomer having a nitrile group include acrylonitrile and methacrylonitrile.
Examples of the monomer having a hydroxy group include -2-hydroxyethyl (meth) acrylate and -2-hydroxypropyl (meth) acrylate.
As the monomer having an amide group, for example, acrylamide, an amine having 1 to 30 carbon atoms and a carboxylic acid having an ethylenically unsaturated bond having 2 to 30 carbon atoms (acrylic acid, methacrylic acid, etc.) can be used by a known method. Examples thereof include the reacted monomer. Examples of vinyl esters include the following. Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl pivalate, vinyl octylate, etc.

Examples of the monomer having a urethane group include the following.
A monomer obtained by reacting an alcohol having 2 to 22 carbon atoms having an ethylenically unsaturated bond with an isocyanate having 1 to 30 carbon atoms by a known method.
A monomer obtained by reacting an alcohol having 1 to 26 carbon atoms with an isocyanate having an ethylenically unsaturated bond and having 2 to 30 carbon atoms by a known method.

Examples of the alcohol having 2 to 22 carbon atoms having an ethylenically unsaturated bond include -2-hydroxyethyl methacrylate and vinyl alcohol.
Examples of isocyanates having 1 to 30 carbon atoms include monoisocyanate compounds, aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, and aromatic diisocyanate compounds.

Examples of the monoisocyanate compound include the following. Benzenesulfonyl isocyanate, tosyl isocyanate, phenylisocyanate, p-chlorophenylisocyanate, butylisocyanate, hexylisocyanate, t-butylisocyanate, cyclohexylisocyanate, octylisocyanate, 2-ethylhexyl isocyanate, dodecylisocyanate, adamantyl isocyanate, 2,6-dimethylphenylisocyanate , 3,5-Dimethylphenyl isocyanate and 2,6-dipropylphenyl isocyanate.
Examples of the aliphatic diisocyanate compound include the following. Trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate.
Examples of the alicyclic diisocyanate compound include the following. 1,3-Cyclopentene diisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated tetramethylxylylene diisocyanate.
Examples of the aromatic diisocyanate compound include the following. Phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate , 4,4'-Diphenyl diisocyanate, 1,5-naphthalenediisocyanate and xylylene diisocyanate.

Examples of alcohols having 1 to 26 carbon atoms include the following. Methanol, ethanol, propanol, isopropyl alcohol, butanol, t-butyl alcohol, pentanol, heptanol, octanol, 2-ethylhexanol, nonanol, decanol, undecyl alcohol, lauryl alcohol, dodecyl alcohol, myristyl alcohol, pentadecyl alcohol, setanol , Heptadecanol, stearyl alcohol, isostearyl alcohol, ellaidyl alcohol, oleyl alcohol, linoleil alcohol, linolenyl alcohol, nonadecil alcohol, henei cosanol, behenyl alcohol, elcil alcohol.
Examples of the isocyanate having 2 to 30 carbon atoms having an ethylenically unsaturated bond include the following. 2-Isocyanatoethyl (meth) acrylate, 2-(0- [1'-methylpropylideneamino] carboxyamino) ethyl (meth) acrylate, 2-[(3,5-dimethylpyrazolyl) carbonylamino] ethyl ( Meta) acrylate and 1,1- (bis (meth) acryloyloxymethyl) ethyl isocyanate.

Examples of the monomer having a urea group include a monomer obtained by reacting an amine having 3 to 22 carbon atoms with an isocyanate having an ethylenically unsaturated bond and having 2 to 30 carbon atoms by a known method.
Examples of amines having 3 to 22 carbon atoms include the following. Primary amines (normal butylamine, t-butylamine, propylamine, isopropylamine, etc.), secondary amines (dinormalethylamine, dinormalpropylamine, dinormalbutylamine, etc.), aniline and cycloxylamine.
The isocyanate having 2 to 30 carbon atoms having an ethylenically unsaturated bond is as described above.
Examples of the monomer having a carboxy group include methacrylic acid, acrylic acid, and -2-carboxyethyl (meth) acrylate.

Among the above, the vinyl esters are non-conjugated monomers, and the reactivity with the first polymerizable monomer is likely to be maintained appropriately, so that the crystallinity of the polymer A or the polymer B is likely to be improved. Of these, vinyl acetate is particularly preferable because it can achieve both low-temperature fixability and bending resistance at a higher level.

The second monomer unit is preferably at least one selected from the group consisting of the structure represented by the following formula (B-1) and the structure represented by the following formula (C-1).

(In formula (B-1), X represents a single bond or an alkylene group having 1 to 6 carbon atoms.
R ₃ is
(I) Nitrile group (-C≡N),
(Ii) Amide group (-C (= O) NHR ₁₅ (R ₁₅ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)),
(Iii) Hydroxy group,
(Iv) -COOR ₁₆ (R ₁₆ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms),
(V) Urethane group (-NHCOOR ₁₇ (R ₁₇ is an alkyl group having 1 to 4 carbon atoms)),
(Vi) Urea group (-NH-C (= O) -NH (R ₁₈ ) ₂ (R ₁₈ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms)),
(Vii) -COO (CH ₂ ) ₂ NHCOOR ₁₉ (R ₁₉ is an alkyl group having 1 to 4 carbon atoms), and (viii) -COO (CH ₂ ) _2- NH-C (= O) -NH (R ₂₀ ). ) ₂ (R ₂₀ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms),
Represents any one functional group selected from the group consisting of
R ₄ represents a hydrogen atom or a methyl group. )

(In the formula (C-1), R ₅ represents an alkyl group having 1 to 4 carbon atoms, and R ₆ represents a hydrogen atom or a methyl group.)

The polymerizable monomer that produces the second monomer unit is composed of the polymerizable monomer represented by the following formula (B-2) and the polymerizable monomer represented by the following formula (C-2). It is preferable that it is at least one selected from the group.

(In the formula (B-2), X represents a single bond or an alkylene group having 1 to 6 carbon atoms.
R ₃ is
(I) Nitrile group (-C≡N),
(Ii) Amide group (-C (= O) NHR ₁₅ (R ₁₅ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)),
(Iii) Hydroxy group,
(Iv) -COOR ₁₆ (R ₁₆ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms),
(V) Urethane group (-NHCOOR ₁₇ (R ₁₇ is an alkyl group having 1 to 4 carbon atoms)),
(Vi) Urea group (-NH-C (= O) -NH (R ₁₈ ) ₂ (R ₁₈ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms)),
(Vii) -COO (CH ₂ ) ₂ NHCOOR ₁₉ (R ₁₉ is an alkyl group having 1 to 4 carbon atoms), and (viii) -COO (CH ₂ ) _2- NH-C (= O) -NH (R ₂₀ ) ) ₂ (R ₂₀ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms),
Represents any one functional group selected from the group consisting of
R ₄ represents a hydrogen atom or a methyl group. )

(In the formula (C-2), R ₅ represents an alkyl group having 1 to 4 carbon atoms, and R ₆ represents a hydrogen atom or a methyl group.)

When a plurality of types of monomer units satisfying the requirements of the first monomer unit are present in the polymer A, the value of SP ₁₁ in the formula (1) is a weighted average of the SP values of each monomer unit. ..
For example, the monomer unit A having an SP value of SP ₁₁₁ is contained in A mol% based on the number of moles of the entire monomer unit satisfying the requirements of the first monomer unit.
The SP value (SP ₁₁ ) when the monomer unit B having the SP value of SP ₁₁₂ is contained in (100-A) mol% based on the number of moles of the entire monomer unit satisfying the requirements of the first monomer unit is given by the following formula. Calculated by.
SP ₁₁ = (SP ₁₁₁ x A + SP ₁₁₂ x (100-A)) / 100
The same calculation is performed when three or more monomer units satisfying the requirements of the first monomer unit are included.

Further, the second monomer unit corresponds to all the monomer units having SP ₂₁ that satisfies the formula (1) and the formula (2) with respect to the SP ₁₁ calculated by the above method.
That is, when the second polymerizable monomer is 2 or more polymerisable monomers, SP ₂₁ denotes a SP value of the monomer units derived from each of the polymerizable monomer, SP ₂₁ -SP ₁₁ Is determined for the monomer unit derived from each second polymerizable monomer.

The polymer A may contain a third monomer unit that does not meet the provisions relating to the first and second monomer units.
Further, the composition according to the polymer B may contain a third polymerizable monomer that does not satisfy the provisions relating to the first and second polymerizable monomers.

Further, the following monomers having no nitrile group, amide group, urethane group, hydroxy group, urea group, or carboxy group as described above can also be used.
For example, styrene such as styrene and o-methylstyrene and derivatives thereof, (meth) such as (meth) acrylate-n-butyl, (meth) acrylate-t-butyl, and (meth) acrylate-2-ethylhexyl. Acrylic acid esters.
When the unit formed by the reaction of these monomers satisfies the formula (1), it becomes the second monomer unit. When these monomers satisfy the formula (3), they become the second polymerizable monomer.
As the third monomer, styrene and methyl (meth) acrylate are preferable.
As the third monomer unit, a monomer unit represented by the following formula (D-1) or a monomer unit represented by the following formula (D-2) is preferable.

(In formula (D-2), R ₇ represents a hydrogen atom or a methyl group.)

From the viewpoint of facilitating the effect of the present invention, particularly low-temperature fixability, the content of the polymer A or the polymer B is preferably 60% by mass or more based on the total mass of the binder resin. More preferably, it is 70% by mass or more, and further preferably 80% by mass or more.

Further, the toner may contain other resins. Examples of other resins include the following resins.
Monopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and its substitutions; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalin copolymer, styrene -Acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinylmethyl ether copolymer, styrene-vinyl ethyl ether Styrene-based copolymers such as copolymers, styrene-vinylmethylketone copolymers, styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenolic resin, natural resin-modified phenolic resin, natural resin-modified maleic acid resin, acrylic Resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, kumaron-inden resin, petroleum resin.
Among these, styrene-based copolymers and polyester resins are preferable. Further, it is preferably amorphous.

<White pigment>
Toner particles include white pigment particles. Here, the white pigment indicates that it is an achromatic particle.
Examples of white pigments include titanium oxide, magnesium oxide, aluminum oxide, zinc oxide, barium sulfate, calcium carbonate, calcium titanate, strontium titanate, silica, clay, talc and the like. These white pigments may be surface-treated particles or unsurface-treated particles.
Among these, titanium oxide and calcium titanate are preferable because they have a high refractive index and, as a result, high concealment.

The white pigment is contained in the toner particles in an amount of 20% by mass or more and 80% by mass or less. The content is preferably 30% by mass or more and 70% by mass or less, and more preferably 40% by mass or more and 60% by mass or less. Within the above range, a sufficient whiteness can be obtained without impairing the chargeability when used as a white toner.
The white pigment has an acidic group and a basic group on the particle surface. The total amount of the surface acidic group amount and the surface basic group amount of the white pigment is 60 μmol / g or more. By having an amount of acidic groups and basic groups in this range on the surface, the surface becomes more hydrophilic, and the second monomer unit portion of the polymer A can be unevenly distributed on the surface of the white pigment.
The amount of surface acidic groups and the amount of surface basic groups of the white pigment can be controlled by changing the type of the base particles of the white pigment, or changing the type and the amount of the surface treatment agent. As the surface treatment agent, for example, the following compounds can be used. Trimethylolethane can be exemplified as a treatment agent for controlling the amount of surface acidic groups, and trimetalolamine acetate can be exemplified as a treatment agent for controlling the amount of surface basic groups.

<Release agent>
The toner may contain a release agent if necessary. Examples of the release agent include the following. Low molecular weight polyolefins such as polyethylene; Silicones having a melting point (softening point) by heating; Fatty acid amides such as oleic acid amide, erucic acid amide, ricinolic acid amide, stearic acid amide; Waxes; carnauba wax, rice wax, candelilla wax, wood wax, plant wax such as jojoba oil; animal wax such as beeswax; montan wax, ozokelite, ceresin, paraffin wax, microcrystallin wax, fisher tropsh wax , Mineral and petroleum waxes such as ester waxes; and their modifications.
The content of the release agent is preferably 1 part by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the binder resin.
The melting point of the release agent is preferably 50 ° C. or higher and 100 ° C. or lower, and more preferably 70 ° C. or higher and 100 ° C. or lower.

<Charge control agent>
If necessary, the toner may contain a charge control agent. As the charge control agent contained in the toner, known ones can be used, but in particular, a metal compound of an aromatic carboxylic acid which is colorless, has a high charge speed of the toner, and can stably maintain a constant charge amount is preferable. Examples of the negative charge control agent include the following. Metallic salicylate compound, metal naphthoic acid compound, metal dicarboxylic acid compound, polymer compound having sulfonic acid or carboxylic acid in the side chain, polymer compound having sulfonate or sulfonic acid esterified product in the side chain. Polymer compounds, boron compounds, urea compounds, silicon compounds, calixarene, which have a carboxylate or a carboxylic acid esterified product in the side chain.
The charge control agent may be added internally or externally to the toner particles.
The content of the charge control agent is preferably 0.2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the binder resin.

<External agent>
If necessary, the toner may contain an external additive. As the external additive, inorganic fine particles (inorganic fine powder) such as silica, titanium oxide, and aluminum oxide are preferable. The inorganic fine particles are preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil or a mixture thereof.
As the external additive for improving the fluidity, inorganic fine particles having a specific surface area of 50 m ² / g or more and 400 m ² / g or less are preferable, and in order to improve durability, the specific surface area is 10 m ² / g or more and 50 m. It is preferably ² / g or less of inorganic fine particles. In order to improve the fluidity and durability of the toner, inorganic fine particles having a specific surface area within the above range may be used in combination.
The external additive is preferably used in an amount of 0.1 part by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner particles. A known mixer such as a Henschel mixer can be used for mixing the toner particles and the external additive.

<Developer>
Although the toner can be used as a one-component developer, it is preferably mixed with a magnetic carrier and used as a two-component developer in order to further improve dot reproducibility. In this case, a stable image can be obtained for a long period of time.
As the magnetic carrier, generally known ones can be used. For example, the following can be mentioned. Oxidized iron powder or unoxidized iron powder; metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, their alloy particles, oxide particles .. A magnetic material-dispersed resin carrier (so-called resin carrier) containing a magnetic material such as ferrite or a magnetic material and a binder resin that holds the magnetic material in a dispersed state.
When the toner is mixed with a magnetic carrier and used as a two-component developer, the mixing ratio of the toner and the carrier at that time is preferably 2% by mass or more and 15% by mass or less as the toner concentration in the two-component developer. More preferably, it is 4% by mass or more and 13% by mass or less.

<Manufacturing method of toner particles>
The method for producing the toner particles is not particularly limited, and conventionally known production methods such as a suspension polymerization method, an emulsion agglutination method, a melt-kneading method, and a dissolution-suspension method can be adopted.
The obtained toner particles may be used as they are as toner. Further, the obtained toner particles may be mixed with inorganic fine particles and, if necessary, other external additives to obtain toner. Examples of the mixing device that can be used for mixing toner particles, inorganic fine particles, and other external additives include the following. Double-con mixer, V-type mixer, drum-type mixer, super mixer, Henschel mixer, Nautamixer, Mechano hybrid (manufactured by Nippon Coke Industries Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Co., Ltd.), etc.
The external additive is preferably used in an amount of 0.1 part by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner particles.

Hereinafter, an example of the toner manufacturing procedure by the pulverization method will be described.
In the raw material mixing step, a predetermined amount of other components such as a binder resin containing an amorphous polyester resin, a wax, a colorant, and a charge control agent, if necessary, are weighed as materials constituting the toner particles. Mix and mix. Examples of the mixing device 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 Industries Co., Ltd.).

Next, the mixed materials are melt-kneaded to disperse wax and the like in the binder resin. In the melt-kneading process, a batch-type kneader such as a pressure kneader or a Bambary mixer or a continuous-type kneader can be used, and a single-screw or twin-screw extruder has become the mainstream because of the advantage of continuous production. ing. For example, KTK type twin-screw extruder (manufactured by Kobe Steel Co., Ltd.), TEM type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikegai Iron Works), twin-screw extruder (Ktk Inc.) Examples include Sea Kay), Co Kneader (Bus), and Kneedex (Nippon Coke Industries Co., Ltd.). Further, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step.

The cooled product of the resin composition is then pulverized to a desired particle size in the pulverization step. In the pulverization step, after coarse pulverization with a pulverizer, further pulverization with a fine pulverizer. Examples of the crusher include a crusher, a hammer mill, and a feather mill. Examples of pulverizers include Cryptron System (Kawasaki Heavy Industries, Ltd.), Super Rotor (Nisshin Engineering Co., Ltd.), Turbo Mill (Turbo Industries, Ltd.), and air jet pulverizers. Can be mentioned.

Then, if necessary, classifying is performed using a classifier or a sieving machine to obtain a classified product (toner particles). Examples of the classifier and the sieving machine include the following. Inertial classification elbow jet (manufactured by Nittetsu Mining Co., Ltd.), centrifugal force classification turboplex (manufactured by Hosokawa Micron Co., Ltd.), TSP separator (manufactured by Hosokawa Micron Co., Ltd.), faculty (manufactured by Hosokawa Micron Co., Ltd.), etc. ..
Among them, Faculti (manufactured by Hosokawa Micron Co., Ltd.) is preferable in that the toner particles can be sphericalized at the same time as the classification, and the transfer efficiency is improved.

Further, if necessary, after pulverization, surface treatment of toner particles such as sphericalization treatment can be performed. Examples of those used for surface treatment include the following. Hybridization system (manufactured by Nara Machinery Co., Ltd.), mechanofusion system (manufactured by Hosokawa Micron Co., Ltd.), faculty (manufactured by Hosokawa Micron Co., Ltd.), Meteole Invo MR Type (manufactured by Nippon Pneumatic Industries Co., Ltd.).

Further, if necessary, an external additive such as inorganic fine particles is externally treated on the surface of the toner particles. Examples of the method for external addition treatment include a method in which toner particles and various known external additives are mixed in a predetermined amount, and the mixture is stirred and mixed using a mixing device. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano hybrid (manufactured by Nippon Coke Industries Co., Ltd.), and a nobilta (manufactured by Hosokawa Micron Co., Ltd.).
Hereinafter, a method for measuring physical properties related to the present invention will be described.

<Method for measuring the content ratio of each monomer unit in polymer A and polymer B>
The content ratio of each monomer unit in the polymer A (or polymer B) is measured by ¹ H-NMR 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: 10500Hz
Number of integrations: 64 times Measurement temperature: 30 ° C
Sample: 50 mg of the measurement sample is placed in a sample tube having an inner diameter of 5 mm, deuterated chloroform (CDCl ₃ ) is added as a solvent, and this is dissolved in a constant temperature bath at 40 ° C. to prepare the sample.

The content ratio of each monomer unit in the polymer A (or the polymer B) is calculated as follows.
From the obtained ¹ H-NMR chart, a peak independent of the peaks assigned to the components of the other monomer units was selected from the peaks attributed to the components of the first monomer unit, and this peak was selected. The integrated value S1 of is calculated.
Similarly, from the peaks attributed to the components of the second monomer unit, a peak independent of the peaks attributed to the components of the other monomer units is selected, and the integrated value S2 of this peak is calculated. ..

Furthermore, when having a third monomer unit, a peak independent of the peaks attributed to the components of other monomer units is selected from the peaks attributed to the components of the third monomer unit, and this peak is selected. The integral value S3 of is calculated.
The content ratio of the first monomer unit is determined as follows using the above integrated values S1, S2, and S3. In addition, n1, n2, and n3 are the number of hydrogens in the component to which the peak focused on each site is assigned.
Content ratio of the first monomer unit (mol%) =
{(S1 / n1) / ((S1 / n1) + (S2 / n2) + (S3 / n3))} x 100

Similarly, the content ratios of the second and third monomer units are determined as follows.
Content ratio of the second monomer unit (mol%) =
{(S2 / n2) / ((S1 / n1) + (S2 / n2) + (S3 / n3))} x 100
Content ratio of the third monomer unit (mol%) =
{(S3 / n3) / ((S1 / n1) + (S2 / n2) + (S3 / n3))} x 100
When a polymerizable monomer containing no hydrogen atom is used as a component other than the vinyl group in the polymer A, the measurement nucleus is set to ¹³ C by using ¹³ C-NMR, and the single pulse mode is used. Measure in ¹ H-NMR and calculate in the same way.

In addition, peaks attributed to mold release agents and other resins may overlap, and independent peaks may not be observed. As a result, the content ratio of the monomer units derived from various polymerizable monomers in the polymer A may not be calculated. In that case, the polymer A'can be produced by the same method without using a release agent or other resin, and the obtained polymer A'can be regarded as the polymer A and analyzed.

<Calculation method of SP value>
SP ₁₂ and SP ₂₂ are obtained as follows according to the calculation method proposed by Fedors. The same applies to SP ₃₂ when the third polymerizable monomer is used.
For each polymerizable monomer, for each atom or atomic group in the molecular structure, the evaporation energy from the table described in "polym. Eng. Sci., 14 (2), 147-154 (1974)". (Δei) (cal / mol) and molar volume (Δvi) (cm ³ / mol) are determined. Then, the SP value is calculated using the following formula.
SP value (J / cm ³ ) ^0.5 = (4.184 × ΣΔei / ΣΔvi) ^0.5
SP ₁₁ and SP ₂₁ are calculated by the same calculation method as above for atoms or atomic groups having a molecular structure in which the double bond of the polymerizable monomer is cleaved by polymerization. The same applies to SP ₃₁ when it has a third monomer unit.

<Measurement of white pigment content in toner particles>
The white pigment is separated from the toner particles from which the external additive has been separated by a method described later using a solvent such as toluene, and the amount thereof is measured.

<Measurement of surface acidic group amount of white pigment>
The white pigment is added to a 0.01 mol / L potassium hydroxide / ethanol solution. Next, a potentiometric titration device (AT-510, manufactured by Kyoto Denshi Kogyo Co., Ltd.) is used to perform potentiometric titration using a 0.01 mol / L hydrochloric acid / ethanol solution of the supernatant. Then, the amount of surface acidic groups of the white pigment is obtained from the difference between the amount of hydrochloric acid required for neutralization and the amount of potassium hydroxide that initially existed.

(When measuring the amount of surface acidic groups of white pigment from toner)
First, the external additive is separated from the toner particles.
160 g of sucrose (manufactured by Kishida Chemical Co., Ltd.) is added to 100 mL of ion-exchanged water and dissolved while boiling to prepare a sucrose concentrate.
31 g of the sucrose concentrate in a centrifuge tube and a 10% by mass aqueous solution of Contaminone N (a 10% by mass aqueous solution of a neutral detergent for cleaning a precision measuring instrument with a pH of 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder). , Wako Pure Chemical Industries, Ltd.) is added in 6 mL to prepare a dispersion.
1.0 g of toner is added to this dispersion, and the toner lumps are loosened with a spatula or the like.

Next, the centrifuge tube is shaken with a shaker. After shaking, the solution is replaced with a glass tube for a swing rotor (50 mL), and the solution is separated by a centrifuge at 3500 rpm and 30 min. By this operation, the toner particles and the detached external additive are separated.
Visually confirm that the toner particles and the aqueous solution are sufficiently separated, collect the toner particles, filter them with a vacuum filter, and then dry them in a dryer for 1 hour or more to separate the toner. Get the particles.

Further, in the obtained toner particles, soluble components other than the white pigment are dissolved in tetrahydrofuran, toluene, hexane and the like. After filtration, the white pigment is recovered by redispersing in water and removing the residual additive by centrifugation, and the amount of surface acidic groups is calculated according to the above measurement method.

<Measurement of surface basic group amount of white pigment>
The white pigment is added to a 0.01 mol / L hydrochloric acid / ethanol solution, treated with ultrasonic waves at 25 ° C. for 1 hour, and centrifuged to obtain a supernatant. Next, a potentiometric titration device (AT-510, manufactured by Kyoto Denshi Kogyo Co., Ltd.) is used to perform potentiometric titration of the supernatant with a 0.01 mol / L potassium hydroxide / ethanol solution. From the difference between the amount of potassium hydroxide required for titration of only the 0.01 mol / L hydrochloric acid / ethanol solution and the amount of potassium hydroxide required for titration of the supernatant, the surface basic group of the white pigment Find the amount.

(When measuring the surface basic amount of white pigment from toner)
Following the measurement of the surface acidic group amount, the white pigment is separated from the toner, and then the surface basic group amount is determined by the above measuring method.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but these are not intended to limit the present invention. In the following formulations, parts are based on mass unless otherwise specified. Table 1 shows the constituent conditions of each toner particle.

<Production Example A1 of Polymer A>
-Solvent: 100.0 parts of toluene-100.0 parts of monomer composition (The monomer composition is a mixture of the following behenyl acrylate, vinyl acetate and styrene in the ratios shown below).
Behenyl acrylate (first polymerizable monomer) 60.0 parts (26.2 mol%)
-Vinyl acetate (second polymerizable monomer) 30.0 parts (57.9 mol%)
-Styrene (third polymerizable monomer) 10.0 parts (15.9 mol%)
-Polymerization initiator t-butyl peroxypivalate (manufactured by NOF CORPORATION: perbutyl PV) 0.5 part

The above materials were put into a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen introduction tube under a nitrogen atmosphere. The inside of the reaction vessel was stirred at 200 rpm and heated to 70 ° C. for 12 hours to carry out a polymerization reaction to obtain a solution in which the polymer of the monomer composition was dissolved in toluene. Subsequently, after the temperature of the solution was lowered to 25 ° C., the solution was poured into 1000.0 parts of methanol with stirring to precipitate the insoluble methanol. The obtained insoluble methanol was filtered off, washed with methanol, and vacuum dried at 40 ° C. for 24 hours to obtain polymer A1. The obtained polymer A1 is a polymer that also satisfies the provisions relating to the polymer B in the second aspect.

When the above polymer A1 was analyzed by NMR, 26.2 mol% of the monomer unit derived from behenyl acrylate, 57.9 mol% of the monomer unit derived from vinyl acetate, and 15.9 mol% of the monomer unit derived from styrene were contained. It was.
The content ratio (mol%) of each polymerizable monomer in the polymer A1 was equal to the content ratio (mol%) of each monomer unit in the polymer A1.
The SP values of the monomer and the monomer unit were calculated. The physical properties are shown in Tables 2 and 3. The unit of SP value is (cal / cm ³ ) ^0.5 .

<Polymer Production Examples A2 to A18>
In the production example of the polymer 1, the polymers A2 to A18 were obtained in the same manner except that the respective monomers and the number of parts by mass were changed as shown in Table 1. The physical properties are shown in Tables 2 and 3.
The content ratio (mol%) of each monomer unit in the polymers A2 to A18 was equal to the ratio (mol%) in the formulations shown in Table 1. The polymers A2 to A11 are polymers that satisfy the provisions relating to the polymer B in the second aspect.
The monomer names in Tables 1 to 3 are as follows.
BEA: Behenyl acrylate CH ₂ = CH-COO- (CH ₂ ) ₂₁ CH ₃
SA: Stearyl Acrylate CH ₂ = CH-COO- (CH ₂ ) ₁₇ CH ₃
MYA: Myricyl acrylate CH ₂ = CH-COO- (CH ₂ ) ₂₉ CH ₃
HA: Hexadecyl acrylate CH ₂ = CH-COO- (CH ₂ ) ₁₅ CH ₃
VA: Vinyl acetate MN: Methacrylonitrile HPMA: Hydroxypropyl methacrylamide MA: Methacrylic acid AM: Acrylamide St: Styrene MM: Methyl methacrylate

<Production example of titanium oxide particles 1>
Titanium tetraisopropoxide was used as a raw material, and the weight was reduced little by little with a chemical pump, and nitrogen gas was used as a carrier gas and sent to glass wool of a vaporizer heated to about 200 ° C. for evaporation. Then, after instantaneously heating and decomposing at about 300 ° C. in the reactor, rapid cooling is performed to collect the product. This was further calcined at about 300 ° C. for about 2 hours to obtain titanium oxide.
Further, 3% by mass of aluminum hydroxide was added, and the cake was filtered and washed to obtain a titanium oxide cake. 2% by mass of trimethylolethane was added to the titanium oxide cake, pulverized by a jet mill, and surface-treated titanium oxide particles 1, that is, oxidation in which some hydroxyl groups on the surface were condensed with some hydroxyl groups of trimethylolethane. Titanium particles 1 were obtained.
The obtained titanium oxide particles 1 had a surface acidic group amount of 43 μmol / g and a surface basic group amount of 28 μmol / g.

<Production example of titanium oxide particles 2>
Titanium oxide particles 2 were obtained in the same manner as in the production example of titanium oxide particles 1 except that aluminum hydroxide was 5% by mass and trimethylolethane was 3% by mass in the production example of titanium oxide particles 1.
The obtained titanium oxide particles 2 had a surface acidic group amount of 39 μmol / g and a surface basic group amount of 23 μmol / g.

<Production example of titanium oxide particles 3>
Titanium oxide particles 3 were obtained in the same manner as in the production example of titanium oxide particles 1 except that aluminum hydroxide was 6% by mass and trimethylolethane was 4% by mass in the production example of titanium oxide particles 1.
The obtained titanium oxide particles 3 had a surface acidic group amount of 27 μmol / g and a surface basic group amount of 25 μmol / g.

<Production example of calcium titanate particles 1>
Titanium tetraisopropoxide is used as a raw material, and the weight is reduced little by little with a chemical pump, and nitrogen gas is used as a carrier gas and sent to glass wool of a vaporizer heated to about 200 ° C. for evaporation. Then, after instantaneously heating and decomposing at about 300 ° C. in the reactor, rapid cooling is performed to collect the product. This was further fired at about 300 ° C. for about 2 hours and pulverized with a jet mill to obtain titanium oxide.
52 parts of titanium oxide and 48 parts of calcium carbonate were dispersed in 100 parts of water, mixed well, and heat-treated at a temperature of about 1,000 ° C. to obtain calcium titanate particles 1.
The obtained calcium titanate particles 1 had a surface acidic group amount of 55 μmol / g and a surface basic group amount of 76 μmol / g.

<Example 1>
The following materials were prepared.
-Polymer A1: 36 parts-Polyester resin 1: 9 parts [Composition (mol%) [Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) Propane: Polyoxyethylene (2.2) ) -2,2-Bis (4-hydroxyphenyl) Propane: Terephthalic acid: Dodecylsuccinic acid: Trimellitic acid = 80:20:75:10:15], Mw = 152,000]
-Titanium oxide particles 1: 50.0 parts (rutile type, volume average particle size 250 nm, total amount of surface acidic groups and surface basic groups 71 μmol / g)
-Fischer-Tropsch wax (melting point 78 ° C): 5.0 parts

The above materials were mixed using a Henschel mixer (FM-75 type, manufactured by Mitsui Mine Co., Ltd.) at a rotation speed of 20 s- ¹ and a rotation time of 5 min, and then a biaxial kneader (PCM-30) set at a temperature of 130 ° C. The mold was kneaded with Ikegai Corp.). The obtained kneaded product was cooled to 25 ° C. and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely crushed product. The obtained pyroclastic material was finely pulverized with a mechanical crusher (T-250, manufactured by Turbo Industries, Ltd.). Further, using Faculti F-300 (manufactured by Hosokawa Micron Co., Ltd.), classification was performed to obtain toner particles 1.

The following silica fine powder was dry-mixed with 100 parts of the obtained toner particles 1 with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) to obtain toner 1. The volume-based median diameter of the toner 1 was 6.5 μm.
1.5 parts of hydrophobized silica fine powder with an average number of primary particles of 10 nm 2.5 parts of hydrophobized silica fine powder with an average number of primary particles of 100 nm

<Examples 2 to 17, Comparative Examples 1 to 8>
In Example 1, the materials used and parts by mass were changed to those shown in Table 4, and the same production was carried out to obtain toners 2 to 17 for Examples and toners 18 to 25 for Comparative Examples. It was.
The following evaluation tests were conducted using each of the above toners. The evaluation results are shown in Table 5.

<Bending resistance (image strength)>
Each of the above toners and a ferrite carrier (volume average particle size 42 μm) surface-coated with a silicone resin were mixed so that the toner concentration was 8% by mass to prepare a two-component developer. Using the obtained two-component developer, a commercially available full-color digital copier (CLC1100, manufactured by Canon Inc.) with the fixing unit removed was used on black paper (Nagatoya Shoten, A4 paper, toner 3285). An unfixed toner image (solid image, 0.9 mg / cm ² ) was formed. The fixing unit removed from a commercially available full-color digital copier (imageRUNNER ADVANCE C5051, manufactured by Canon Inc.) was modified so that the fixing temperature could be adjusted, and the process speed was set to 357 mm / sec at room temperature of 15 ° C and humidity of 10%. Then, the unfixed image was fixed.

Fold the fixed image at the maximum temperature that can be fixed (the upper limit temperature at which offset does not occur) in a cross shape, and slide it 5 times with a soft thin paper (trade name "Dasper", manufactured by Ozu Corporation) while applying a load of 4.9 kPa. I rubbed it. Then, the area of 512 pixels square of the cross part was photographed with a CCD camera at a resolution of 800 pixels / inch. The threshold value was set to 60%, the image was binarized, and the area ratio of the black portion where the toner was peeled off was measured. The smaller the area ratio of the black part, the better the bending resistance.

(Evaluation criteria)
A: Area ratio of black part is less than 2.0% B: Area ratio of black part is 2.0% or more and less than 3.5% C: Area ratio of black part is 3.5% or more and less than 5.0% D: Black part Area ratio is 5.0% or more

<Low temperature fixability of toner>
Using a full-color copying machine imagePress C800 manufactured by Canon Inc. as an image forming apparatus, the two-component developer to be evaluated was put into a cyan developing device of the image forming apparatus, and the evaluation described later was performed.
The modification points are that the mechanism for discharging the excess magnetic carrier inside the developing device from the developing device has been removed, and the fixing temperature can be changed freely.
The evaluation conditions are shown below.
Paper: Black paper (Nagatoya Shoten, A4 paper, Na-3285)
Amount of toner on paper: 0.55 mg / cm ²
(Adjusted by the DC voltage VDC applied to the developer carrier, the charging potential VD on the surface of the electrostatic latent image carrier, and the laser power)
Evaluation image: An image of 2 cm x 5 cm is placed in the center of the above A4 paper Test environment: Low temperature and low humidity environment: Temperature 15 ° C / Relative humidity 10% (hereinafter "L / L")
Process speed: 450mm / sec
The fixing temperature was raised by 5 ° C. in order from 100 ° C., and the lower limit temperature at which no offset occurred was defined as the lower limit temperature for fixing. C or higher was judged to be good in the following evaluation criteria for the lower limit temperature of fixing. The results are shown in Table 5.

(Evaluation criteria for lower limit temperature of fixing)
A: Less than 115 ° C B: 115 ° C or more and less than 125 ° C C: 125 ° C or more and less than 140 ° C D: 140 ° C or more

<Whiteness (brightness L ^* )>
Unfixed formed on black paper at 150 ° C. in the same manner as in the evaluation of bending resistance using a fixing unit removed from a commercially available full-color digital copier (imageRUNNER ADVANCE C5051, manufactured by Canon Inc.). The image was fixed. The brightness L ^* of the obtained fixed image was measured using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite) and evaluated according to the following criteria. C or higher was judged to be good in the following evaluation criteria for whiteness. The evaluation results are shown in Table 5.

(Evaluation criteria for whiteness)
A: L ^* is 82 or more B: L ^* is 78 or more and 81 or less C: L ^* is 74 or more and 77 or less D: L ^* is 73 or less

Claims (14)

A toner having toner particles containing a binder resin and a white pigment.
The toner particles contain the white pigment in an amount of 20% by mass or more and 80% by mass or less.
The binder resin contains a first monomer unit represented by the following formula (A-1) and a polymer A having a second monomer unit different from the first monomer unit.

(In the formula (A-1), R ₁ represents an alkyl group having 18 to 36 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group.)
The content ratio of the first monomer unit in the polymer A is 5.0 mol% to 60.0 mol% based on the total number of moles of all the monomer units in the polymer A.
The content ratio of the second monomer unit in the polymer A is 20.0 mol% to 95.0 mol% based on the total number of moles of all the monomer units in the polymer A.
When the SP value of the first monomer unit is SP ₁₁ (J / cm ³ ) ^0.5 and the SP value of the second monomer unit is SP ₂₁ (J / cm ³ ) ^0.5 , the SP ₁₁ and the SP ₂₁ satisfy the following equations (1) and (2).
3.00 ≤ (SP _21- SP ₁₁ ) ≤ 25.00 ... (1)
21.00 ≤ SP ₂₁ ... (2)
A white toner characterized in that the total amount of the surface acidic group amount and the surface basic group amount of the white pigment is 60 μmol / g or more. The first aspect of claim 1, wherein the second monomer unit is at least one selected from the group consisting of a structure represented by the following formula (B-1) and a structure represented by the following formula (C-1). White toner.

(In formula (B-1), X represents a single bond or an alkylene group having 1 to 6 carbon atoms.
R ₃ is
(I) Nitrile group (-C≡N),
(Ii) Amide group (-C (= O) NHR ₁₅ (R ₁₅ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)),
(Iii) Hydroxy group,
(Iv) -COOR ₁₆ (R ₁₆ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms),
(V) Urethane group (-NHCOOR ₁₇ (R ₁₇ is an alkyl group having 1 to 4 carbon atoms)),
(Vi) Urea group (-NH-C (= O) -NH (R ₁₈ ) ₂ (R ₁₈ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms)),
(Vii) -COO (CH ₂ ) ₂ NHCOOR ₁₉ (R ₁₉ is an alkyl group having 1 to 4 carbon atoms), and (viii) -COO (CH ₂ ) _2- NH-C (= O) -NH (R ₂₀ ) ) ₂ (R ₂₀ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms),
Represents any one functional group selected from the group consisting of
R ₄ represents a hydrogen atom or a methyl group. )

(In the formula (C-1), R ₅ represents an alkyl group having 1 to 4 carbon atoms, and R ₆ represents a hydrogen atom or a methyl group.) The white toner according to claim 2, wherein the second monomer unit is the formula (C-1). The white toner according to claim 3, wherein in the formula (C-1), R ₅ is a methyl group and R ₆ is a hydrogen atom. In addition to the first monomer unit and the second monomer unit, the polymer A contains a monomer unit represented by the following formula (D-1) and a monomer represented by the formula (D-2). The white toner according to claim 2, which has any monomer unit selected from the group consisting of units.

(In formula (D-2), R ₇ represents a hydrogen atom or a methyl group.) The white toner according to claim 1, wherein the content of the polymer A is 60% by mass or more with respect to the total mass of the binder resin. The white toner according to claim 1, wherein the white pigment is titanium oxide or calcium titanate. A toner having toner particles containing a binder resin and a white pigment.
The toner particles contain the white pigment in an amount of 20% by mass or more and 80% by mass or less.
Polymer B, which is a polymer of a composition in which the binder resin contains a first polymerizable monomer and a second polymerizable monomer different from the first polymerizable monomer. Contains,
The first polymerizable monomer is a polymerizable monomer represented by the following formula (A-2).

(In the formula (A-2), R ₁ represents an alkyl group having 18 to 36 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group.)
The content of the first polymerizable monomer in the composition is 5.0 mol% to 60.0 mol% with respect to the total number of moles of the total polymerizable monomers in the composition. ,
The content of the second polymerizable monomer in the composition is 20.0 mol% to 95.0 mol% with respect to the total number of moles of the total polymerizable monomer in the composition. ,
The SP value of the first polymerizable monomer is SP ₁₂ (J / cm ³ ) ^0.5, and the SP value of the second polymerizable monomer is SP ₂₂ (J / cm ³ ) ^0.5. Then, the SP ₁₂ and the SP ₂₂ satisfy the following formula (3) and the following formula (4).
0.60 ≦ (SP ₂₂ −SP ₁₂ ) ≦ 15.00 ・ ・ ・ (3)
18.30 ≤ SP ₂₂ ... (4)
A white toner characterized in that the total amount of the surface acidic group amount and the surface basic group amount of the white pigment is 60 μmol / g or more. The second polymerizable monomer is selected from the group consisting of a polymerizable monomer represented by the following formula (B-2) and a polymerizable monomer represented by the following formula (C-2). The toner according to claim 8, which is at least one.

(In the formula (B-2), X represents a single bond or an alkylene group having 1 to 6 carbon atoms.
R ₃ is
(I) Nitrile group (-C≡N),
(Ii) Amide group (-C (= O) NHR ₁₅ (R ₁₅ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)),
(Iii) Hydroxy group,
(Iv) -COOR ₁₆ (R ₁₆ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms),
(V) Urethane group (-NHCOOR ₁₇ (R ₁₇ is an alkyl group having 1 to 4 carbon atoms)),
(Vi) Urea group (-NH-C (= O) -NH (R ₁₈ ) ₂ (R ₁₈ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms)),
(Vii) -COO (CH ₂ ) ₂ NHCOOR ₁₉ (R ₁₉ is an alkyl group having 1 to 4 carbon atoms), and (viii) -COO (CH ₂ ) _2- NH-C (= O) -NH (R ₂₀ ) ) ₂ (R ₂₀ is an independent hydrogen atom or an alkyl group having 1 to 6 carbon atoms),
Represents any one functional group selected from the group consisting of
R ₄ represents a hydrogen atom or a methyl group. )

(In the formula (C-2), R ₅ represents an alkyl group having 1 to 4 carbon atoms, and R ₆ represents a hydrogen atom or a methyl group.) The white toner according to claim 8, wherein the second polymerizable monomer is a polymerizable monomer represented by the formula (C-2). The white toner according to claim 10, wherein in the polymerizable monomer represented by the formula (C-2), R ₅ is a methyl group and R ₆ is a hydrogen atom. The composition is at least one polymerizable simpler selected from the group consisting of styrene, methyl methacrylate and methyl acrylate in addition to the first polymerizable monomer and the second polymerizable monomer. The white toner according to claim 9, which comprises a polymer. The white toner according to claim 8, wherein the content of the polymer B is 60% by mass or more with respect to the total mass of the binder resin. The white toner according to claim 8, wherein the white pigment is titanium oxide or calcium titanate.