JP2005215491A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner which is excellent in low-temperature fixability, high-temperature offset resistance and blocking resistance, can perform favorable coloring and is excellent in fluidity and electrostatic charge property. <P>SOLUTION: In the toner consisting of toner particles containing resin composition for toner containing crystalline polymer having 180 to 280°C melting point and noncrystalline polyester having 30 to 80°C glass transition temperature and silica particles adhered to the surface of the toner particles, surface processing by hexamethyldisilazane is performed to the silica particles. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a toner that is excellent in low-temperature fixability, high-temperature offset resistance, and blocking resistance, can perform good color development, and has excellent fluidity and charging characteristics.

A dry development method is frequently used as a method for developing an electrostatic image in electrophotography or the like. In the dry development system, the toner is usually charged by friction with iron powder, glass beads, etc., called a carrier, which adheres to the electrostatic latent image on the photoreceptor by electrical attraction, and then transferred onto the paper, It is fixed by a heating roller or the like and becomes a permanent visible image.

As a fixing method, a heating roller method is generally used in which a toner image of a fixing sheet is passed through a surface of a heat fixing roller formed with a material having releasability with respect to a toner while being in pressure contact. ing.

In this heat fixing roller method, there is a demand for a toner that can be fixed at a lower temperature in order to improve economy such as power consumption and to increase the copying speed.
However, when trying to improve the low-temperature fixability described above, an offset phenomenon in which a part of the toner adheres to the surface of the heat-fixing roller and retransfers to the paper is likely to occur, or the resins are subjected to various environments. There is a problem that a blocking phenomenon in which toner aggregates easily occurs due to heat.

In conventional polyester-based toners, a polyfunctional monomer having three or more functional groups is usually copolymerized to form a chemically cross-linked structure in the polymer to maintain high temperature offset resistance. However, in such a method, since there is a component that does not dissolve in the polymer, unevenness is generated on the print surface after fixing with the fixing roll, so that the gloss is inferior or the low-temperature fixability is limited.

In order to solve these problems, Patent Document 1 discloses that a unit derived from terephthalic acid and a linear alkylene glycol having 2 to 6 carbon atoms as a binder resin of the toner is 50 mol% or more based on the total monomer units used. It has been proposed to use a crystalline polyester resin containing.
However, in this technique, since only the crystalline polyester resin is used, it is difficult to maintain the high-temperature offset resistance and the blocking resistance without impairing the low-temperature fixability because the temperature range capable of fixing is narrow.

In Patent Document 2, as a toner binder resin, a trivalent or higher polyvalent monomer, an aromatic dicarboxylic acid, and an aliphatic alcohol containing 50 mol% or more of a branched aliphatic alcohol are polymerized. It has been proposed to use an amorphous polyester resin.
However, in this technique, only the amorphous polyester resin is used, so that the low-temperature fixability is not sufficient.

Patent Document 3 and Patent Document 4 propose a toner containing two types of polyesters having different softening points as a resin for toner as a toner having an excellent balance between low-temperature fixability and high-temperature and high-temperature offset resistance.
However, the compatibility of the above two types of polyesters is not sufficient, and there is a problem that polyesters having a low softening point tend to cause blocking, or adhere to the fixing roller and cause filming. There was also a problem that the transparency of the resin was low because the solubility was not sufficient.

Patent Document 5 proposes to use a block copolymer of a low-melting crystalline polyester and a high-melting crystalline polyester as a binder resin for the toner.
However, this technique has a problem that a transparent resin cannot be obtained because the binder resin becomes a cloudy resin.

Further, since the blocking phenomenon is likely to occur when the toner is exposed to the glass transition temperature of the toner resin or higher, the polyester resin for the toner that does not easily cause the blocking phenomenon has been studied. As a polyester resin for toner that does not cause a blocking phenomenon, although the low-temperature fixing temperature is not so low, for example, Patent Document 6 shows that the polyester resin composition is effective as a specific composition. 7 shows that it is effective when the composition of the polyester resin is specified and the glass transition temperature is 45 to 70 ° C.

However, although these techniques make it difficult for the blocking phenomenon to occur at room temperature, even if these toner resins are used, if the toner is exposed to a temperature near the glass transition temperature of the toner resin, the blocking phenomenon will still occur. There was a problem that.

Further, toner used for electrophotography and the like is required to have excellent fluidity in order to prevent the toners from aggregating and stabilize the supply of toner to the developing roller and the like. Further, when charging characteristics such as charge amount, charge amount distribution, and rising of charge are not appropriate, a toner having good charging characteristics is required because image quality is deteriorated.
In conventional toners, as a means of improving fluidity and improving charging characteristics, silica powder surface-treated with a hydrophobizing agent such as dimethyldichlorosilane is kneaded into a toner resin composition when the toner is manufactured. A method of externally adding silica particles to the surface of toner particles has been performed.
However, even when silica powder surface-treated with such a hydrophobizing agent is used, it cannot be said that the fluidity and charging characteristics of the toner are still sufficient, and problems such as deterioration in print quality occur. Was.

Japanese Patent No. 2988703 Japanese Patent No. 2704282 Japanese Patent Laid-Open No. 4-97366 JP-A-4-313760 Japanese Patent Publication No. 5-44032 JP-A-4-337774 Japanese Patent Laid-Open No. 10-36490

An object of the present invention is to provide a toner that is excellent in low-temperature fixability, high-temperature offset resistance and anti-blocking properties, can perform good color development, and has excellent fluidity and charging characteristics. To do.

The present invention relates to a crystalline polymer having a melting point of 180 to 280 ° C. and a glass transition temperature of 30 to 8
A toner comprising toner particles containing a toner resin composition containing an amorphous polyester at 0 ° C. and silica particles adhering to the surface of the toner particles, wherein the silica particles are The toner has been surface-treated with silazane.
The present invention is described in detail below.

The toner of the present invention comprises toner particles and silica particles attached to the surface of the toner particles.
The toner particles contain a resin composition for toner. The toner resin composition contains a crystalline polymer having a melting point of 180 to 280 ° C. and an amorphous polyester having a glass transition temperature of 30 to 80 ° C.
In the present specification, the crystalline polymer means a polymer that exhibits a sharp and clear melting point peak when the differential heat is measured by a differential scanning calorimeter, and has a crystallinity of more than 10%. The polyester means a polyester having a crystallinity of 10% or less without showing a sharp and clear melting point peak when differential heat is measured by a differential scanning calorimeter.

The toner of the present invention comprising toner particles containing the toner resin composition has a low temperature fixability,
Excellent high-temperature offset resistance and blocking resistance, and good color development can be performed. This is because, in the above resin composition for toner, the crystalline components in the crystalline polymer having a high melting point form a physically cross-linked structure in the amorphous polyester, while the amorphous component in the crystalline polymer having a high melting point is formed. Ingredients and amorphous polyester are intertwined to form a kind of network structure. By forming such a network structure, there is little decrease in viscosity at high temperatures, and low temperature fixability and storage stability are reduced. This is considered to be because good offset resistance can be exhibited without causing the occurrence of such a problem.

That is, in the toner resin composition, a high melting point crystalline polymer capable of forming a physical cross-linked structure, and an amorphous polyester having a glass transition temperature of 30 to 80 ° C. without forming a physical cross-linked structure. By mixing, it is possible to improve high-temperature offset resistance and at the same time improve gloss and low-temperature fixability. By containing a crystalline polymer capable of forming a physical cross-linked structure and an amorphous polyester that does not form a physical cross-linked structure and has a glass transition temperature of 30 to 80 ° C., the polymer viscosity is increased. The offset property can be improved. On the other hand, it is considered that the viscosity of the polymer is lowered when the pressure is applied by the fixing roll, so that the smoothness of the printing surface is increased, the gloss is improved and the low temperature fixing property is improved.

Further, the toner of the present invention has excellent image reproducibility. This is because the above-mentioned network structure is formed in the entire resin composition for toner, and thus the toner obtained in the pulverization process has stable chargeability, no fog, and excellent image reproducibility. .

At this time, it is preferable that the crystals forming the physical cross-linked structure have a size of 1 μm or less and are finely dispersed uniformly in the toner resin composition. Due to the fine dispersion of fine crystals, the network structure becomes more stable and exhibits excellent effects.
In order to express such a nano-order uniform fine dispersion structure and form the above-mentioned network structure, it is very important that the compatibility between the crystalline polymer and the amorphous polyester is high, It is important that the crystallinity of the crystalline polymer is high.

In the toner resin composition, a preferable lower limit of the endothermic amount at the melting point measured using a differential scanning calorimeter (DSC) is 1 mJ / mg, and a preferable upper limit is 20 mJ / mg. 1m
If it is less than J / mg, the above-mentioned network structure may not be formed and the desired effect such as high-temperature offset resistance may not be obtained. If it exceeds 20 mJ / mg, the viscosity of the polymer during pressurization with a fixing roll may be reduced. In some cases, the surface of the print after fixing may not be sufficiently lowered, resulting in unevenness on the printed surface, resulting in poor gloss or low temperature fixability. A more preferred lower limit is 2 mJ / mg, and a more preferred upper limit is 15 mJ / mg.

The lower limit of the melting point of the crystalline polymer is 180 ° C., and the upper limit is 280 ° C. If it is lower than 180 ° C., the high temperature hot offset resistance becomes insufficient, or filming is likely to occur, resulting in insufficient durability. When it exceeds 280 ° C., it is necessary to melt at a high temperature exceeding 280 ° C. at the time of mixing with the amorphous polyester, so that the productivity is remarkably deteriorated. The preferred lower limit is 200 ° C., the preferred upper limit is 240 ° C., and the more preferred lower limit is 22 ° C.
0 ° C.

In order to shorten the rise time (warm-up time) after switching on in a copying machine or printer, it is necessary to quickly raise the fixing roller to a predetermined fixing temperature. Initially, it is hotter than a predetermined fixing temperature. Therefore, in order to perform good printing even in this state, the toner must have good hot offset resistance at high temperatures. The lower the fixing temperature and the higher the hot offset temperature, the shorter the warm-up time. Usually, in order to sufficiently increase the hardware design width, the hot offset resistance temperature is required to be 180 ° C. or higher. When the crystalline polymer has a melting point of 180 ° C. or higher, the crystal part of the crystalline polymer is not melted even at a high temperature, and the above-described network structure is maintained, so that the high temperature hot offset resistance is considered to be improved. In addition, as the speed of copying machines and printers increases, there is a demand for a toner that does not generate fine powder and does not cause filming even under high speed operation. In particular, non-magnetic one-component toner that is charged by mechanical contact with the blade has a higher demand for durability. When the melting point of the crystalline polymer is 180 ° C., the cohesive force of the crystalline part of the crystalline polymer is increased, and the above-described network structure is strengthened, so that the durability is considered to be improved.

The crystalline polymer has a preferred lower limit of the endothermic amount at the melting point measured using a differential scanning calorimeter (DSC) of 25 mJ / mg, and a preferred upper limit of 150 mJ / mg. 25mJ /
If it is less than mg, it may be difficult to form the above-described network structure, so that the desired effect such as high-temperature offset resistance may not be obtained. If it exceeds 150 mJ / mg, the viscosity of the polymer during pressurizing with a fixing roll In some cases, the surface of the print after fixing is not sufficiently lowered, resulting in unevenness on the printed surface, resulting in poor gloss and low temperature fixability. The preferred lower limit is 40 mJ / mg and the preferred upper limit is 100.
mJ / mg.
In addition, although it does not specifically limit about the measurement conditions of a differential scanning calorimeter (DSC), For example, J
In accordance with IS K 7121, it can be measured by a method of heating 10 mg of a sample at a heating rate of 10 ° C./min.

The crystalline polymer has a preferable lower limit of the weight average molecular weight of 30,000 and a preferable upper limit of 300,000. If it is less than 30,000, the offset resistance and durability of the resulting toner may be insufficient, and if it exceeds 300,000, the low-temperature fixability and gloss may be inferior. This is considered to be because the above-described network structure cannot be sufficiently formed if it is out of this range. A more preferred lower limit is 50,000, a more preferred upper limit is 200,000, a still more preferred lower limit is 80,000, and a still more preferred upper limit is 150,000.

Although it does not specifically limit as said crystalline polymer, Crystalline polyester or crystalline polyamide is suitable.
The crystalline polyester can be obtained by condensation polymerization of dicarboxylic acid and diol.
Examples of the dicarboxylic acid include o-phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, and itacone. Examples include acids, decamethylene carboxylic acids, anhydrides and lower alkyl esters thereof. Among these, terephthalic acid, naphthalenedicarboxylic acid, and anhydrides and lower alkyl esters thereof are preferably used for imparting crystallinity.

Examples of the diol include ethylene glycol, 1,3-propanediol, 1,
4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3 -Butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-
Aliphatic diols such as hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol; 2 , 2-bis (4-hydroxycyclohexyl) propane, 2,2-
Alkylene oxide adduct of bis (4-hydroxycyclohexyl) propane, 1,4
-Alicyclic diols such as cyclohexanediol and 1,4-cyclohexanedimethanol.

Among the crystalline polyesters, polybutylene terephthalate (PBT),
Polyethylene terephthalate (PET) is preferred.
Since polybutylene terephthalate (PBT) has a high crystallization rate and a high degree of crystallization, a toner obtained using this has excellent offset resistance. Further, since the compatibility with the amorphous polyester is excellent, the toner obtained using the polyester has excellent low-temperature fixability and gloss.
Since polyethylene terephthalate (PET) has a high crystalline melting point, the toner obtained using this has excellent offset resistance at high temperatures. Polyethylene terephthalate (PET) is inferior to polybutylene terephthalate (PBT) in terms of crystallization speed and crystallinity, but these points can be improved by adding a crystal nucleating agent.
These crystalline polyesters may be used alone or in combination of two or more.

Examples of the crystalline polyamide include 6-nylon, 6,6-nylon, 4,6-nylon,
11-nylon, 12 nylon, etc. are mentioned. Of these, 6-nylon and 6,6-nylon are preferred because they have high crystal cohesion and are excellent in the effect of improving high-temperature offset resistance. A polyamide-polyester copolymer obtained by copolymerizing polyester with these crystalline polyamides is also preferable because of excellent compatibility with the amorphous polyester. These crystalline polyamides may be used alone or in combination of two or more.
Since the crystalline polyamide has a strong intermolecular cohesive force, the high temperature offset resistance can be exhibited only by using a small amount of the polyester, and the strength of the resin itself can be increased.

The lower limit of the glass transition temperature of the non-crystalline polyester is 30 ° C., and the upper limit is 80 ° C. 30
If it is less than 0 ° C., high-temperature offset resistance and blocking resistance cannot be sufficiently obtained, and if it exceeds 80 ° C., low-temperature fixability is inferior. A preferred lower limit is 50 ° C and a preferred upper limit is 65 ° C.

The non-crystalline polyester can be obtained by polycondensing a dicarboxylic acid and a diol.
The glass transition temperature of non-crystalline polyester is such that aromatic dicarboxylic acids such as terephthalic acid improve the glass transition temperature, and long-chain aliphatic dicarboxylic acids such as sebacic acid and adipic acid lower the glass transition temperature. Since it has a function, the target glass transition temperature can be achieved by appropriately combining these dicarboxylic acids. However, even if an objective glass transition temperature can be achieved by appropriately combining an aromatic dicarboxylic acid and a long-chain aliphatic dicarboxylic acid, the softening temperature tends to be too high.
Therefore, the non-crystalline polyester comprises a polyvalent carboxylic acid and a polyhydric alcohol containing at least either a divalent bending monomer capable of introducing a bent molecular structure into the molecular chain or a divalent monomer having a branched chain. It is preferable to polymerize the monomer mixture containing.
A polymer obtained by polymerizing a monomer mixture containing these divalent bending monomers and divalent monomers having a branched chain can easily achieve both a desired glass transition temperature and a low softening temperature, and can be crystallized. It can be effectively suppressed.

As the divalent bending monomer, an aromatic dicarboxylic acid in which the ortho position or the meta position is substituted with a carboxyl group, an aromatic diol in which the ortho position or the meta position is substituted with a hydroxyl group,
Polycarboxylic aromatic dicarboxylic acids having a carboxyl group at an asymmetric position, polycyclic aromatic diols having a hydroxyl group at an asymmetric position, and other monomers that can introduce a molecular structure bent into the molecular chain of the polymer are limited to dicarboxylic acids and diols. For example, it may be an anhydride or lower ester of a dicarboxylic acid, a monohydroxymonocarboxylic acid, etc., for example, phthalic anhydride, o-phthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,7 Dicarboxylic acids such as naphthalenedicarboxylic acid and anhydrides and lower esters thereof; monohydroxymonocarboxylic acids such as salicylic acid and 3-hydroxy-2-naphthalenecarboxylic acid; catechol,
Examples include diols such as 1,4-cyclohexanedimethanol.

A divalent monomer having a branched chain effectively suppresses crystallization of the polymer due to steric hindrance of the branched chain. Examples of the monomer having a branched chain that can effectively suppress crystallization include an aliphatic diol having a branched alkyl chain and an alicyclic diol having a branched alkyl chain. The alicyclic diol is preferably an alicyclic diol in which a plurality of alicyclic diols are linked by a branched alkylene chain.
The divalent monomer having a branched chain is not particularly limited. For example, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane- 1,3-diol), 1,2-hexanediol, 2,5
-Hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1
Aliphatic diols such as 1,3-propanediol and 2,4-diethyl-1,5-pentanediol; 2,2-bis (4-hydroxycyclohexyl) propane and 2,2-bis (4-hydroxycyclohexyl) propane And alicyclic diols such as alkylene oxide adducts.
Among them, terephthalic acid, neopentyl glycol, ethylene glycol and / or
Alternatively, an amorphous polyester obtained by polymerizing a monomer mixture containing 1,4-butanediol as a main component is preferable because it is excellent in low-temperature fixability and transparency.

The crystalline polymer and the non-crystalline polyester are preferably compatible. When the crystalline polymer and the non-crystalline polyester are compatible, the toner resin composition is colorless and transparent, and can be suitably used as a color toner resin composition capable of performing good color development. In addition, since it has high resin strength, it can be suitably used as a resin composition for toner having excellent high-temperature offset resistance.
The term “compatible” refers to a state in which the crystalline polymer and the non-crystalline polyester are uniformly mixed. These may be completely compatible or partially compatible. .

Thus, in order for the crystalline polymer and the non-crystalline polyester to be compatible, the glass transition temperature of the crystalline polymer is A (° C.), and the glass transition temperature of the non-crystalline polyester is B (° C.). The glass transition temperature C (° C.) of the toner resin composition preferably satisfies the following formula (1).

      sA + tB-2 ≦ C ≦ sA + tB + 2 (1)

In formula (1), s represents the weight fraction of the crystalline polymer in the toner resin composition, and t represents the weight fraction of the amorphous polymer in the toner resin composition.
When the glass transition temperature of the resin composition for toner satisfies the formula (1), the crystalline polymer and the non-crystalline polyester are very well compatible.

If the crystalline polyester is used as the crystalline polymer, and the crystalline polyester and the amorphous polyester have a common monomer component such as terephthalic acid as a constituent monomer, compatibility can be improved. it can. For example, the crystalline polyester may be polybutylene terephthalate (PBT) or polyethylene terephthalate (PE
T) and the non-crystalline polyester is obtained by polymerizing a monomer mixture containing terephthalic acid, neopentyl glycol, and ethylene glycol and / or 1,4-butanediol as a main component. Is well compatible.

As the content of the crystalline polymer and the non-crystalline polyester in the resin composition for toner, a preferred lower limit of the crystalline polymer content is 2% by weight, and a preferred upper limit is 30% by weight. The preferable lower limit of the content of the crystalline polyester is 98% by weight, and the preferable upper limit is 70% by weight.
When the content of the crystalline polymer is less than 2% by weight, the high temperature offset resistance may be inferior, and when it exceeds 30% by weight, the low temperature fixability may be inferior. A more preferred lower limit is 3% by weight, a more preferred upper limit is 20% by weight, a still more preferred lower limit is 5% by weight, and a still more preferred upper limit is 15% by weight.

The toner resin composition further has a weight average molecular weight of 20,000 to 300,000, preferably 30,000 to 2.
It is preferable to contain 100,000 amorphous polyesters. By blending such a high molecular weight amorphous polyester, the high temperature offset resistance of the resulting toner can be further improved.
The high molecular weight non-crystalline polyester is not particularly limited, for example, isophthalic acid,
Examples thereof include polyethylene terephthalate composed of terephthalic acid and ethylene glycol, polyethylene terephthalate composed of 1,4-cyclohexanedimethanol, ethylene glycol and terephthalic acid.
The blending amount of the high molecular weight amorphous polyester is not particularly limited, but the preferable lower limit is 2% by weight and the preferable upper limit is 30% by weight with respect to the entire resin composition for toner. If it is less than 2% by weight, a sufficient effect of improving high-temperature offset resistance may not be obtained, and if it exceeds 30% by weight, the low-temperature fixability may be inferior.

The toner resin composition preferably also contains a crystal nucleating agent. By containing the crystal nucleating agent, crystallization of the crystalline polymer component can be promoted. Although it does not specifically limit as said crystal nucleating agent, For example, metal oxides, such as a zinc oxide, a magnesium oxide, a silicon oxide, iron oxide (III), a titanium oxide; Calcium carbonate, magnesium carbonate,
Inorganic salts such as calcium silicate, lead silicate, magnesium silicate, calcium phosphate, calcium sulfate, barium sulfate, potassium titanate; organic acid salts such as calcium oxalate, sodium oxalate; talc, kaolin, clay mica, wolast Examples include clays such as knights. In addition, the shape of the crystal nucleating agent is not particularly limited, and may be amorphous, in addition to a plate shape and a spherical shape.

When the toner resin composition was subjected to a shear strain of 450% at 190 ° C.,
It is preferable that the slope K of the relaxation modulus curve from 0.02 seconds to 0.1 seconds after applying the shear strain represented by the following formula (2) is −27 or more.

In the formula, G (0.02) represents a relaxation elastic modulus 0.02 seconds after applying a shear strain, and G (0
. 1) represents the relaxation elastic modulus 0.1 seconds after applying a shear strain.

The gradient K of the relaxation elastic modulus curve represents the elastic behavior of the substance, and the closer to 0, the closer to rubber elasticity. The slope K of the relaxation elastic modulus curve is −27 or more because the above-mentioned network structure is formed in the resin composition for toner, and the crystal having the physically cross-linked structure dispersed uniformly is the center. Furthermore, it is considered that the rubber-like property is expressed by the structure in which the amorphous component in the crystalline polymer having a high melting point and the amorphous polyester are entangled with each other. Therefore, the toner resin composition having a slope K of the relaxation elastic modulus curve of −27 or more is excellent in low-temperature fixability, high-temperature offset resistance and blocking resistance,
It is possible to provide a toner that performs good color development. When the slope K of the relaxation elastic modulus curve is less than −27, it is considered that the above-described network structure is not sufficiently formed, and the desired effect may not be obtained.
The relaxation elastic modulus is, for example, obtained by melting the toner resin and then molding it into a disk shape of a predetermined size as a test sample, and using a relaxation elastic modulus measuring device (for example, RMS-800 manufactured by Rheometrics). Etc.).

The acid value of the toner resin composition is not particularly limited, but the preferred lower limit is 1 KOHm.
g / g, and a preferable upper limit is 30 KOH mg / g. Such an acid value is attributed to an acidic functional group at the end of the main chain of the crystalline polymer or the amorphous polyester, specifically, for example, a carboxyl group. When the acid value is in this range, the toner obtained is excellent in low-temperature fixability, and the affinity with paper is also improved.
The toner resin composition contains only a polymer having a molecular weight of about several hundred thousand, unlike the conventional toner resin composition having a molecular weight of 1,000,000. The groups are relatively uniformly distributed, and higher low-temperature fixability can be obtained.

The method for producing the resin composition for toner is not particularly limited. For example, a method in which the crystalline polymer and the amorphous polyester are separately mixed at a temperature equal to or higher than the melting point of the crystalline polymer. Can be mentioned.

In the toner of the present invention, silica particles that have been surface-treated with hexamethyldisilazane adhere to the surface of the toner particles.
As a result of intensive studies, the present inventors attached silica particles that have been surface-treated with hexamethyldisilazane to the surfaces of the toner particles containing the toner resin composition.
Compared to the case where silica particles that have been surface-treated with dimethyldichlorosilane or the like are adhered to the toner particles while exhibiting various properties such as low-temperature fixability, high-temperature offset resistance, and blocking resistance required for the toner. As a result, the inventors have found that the fluidity and charging characteristics are excellent, and have completed the present invention.

It does not specifically limit as a magnitude | size of the silica particle to which the surface treatment by the said hexamethyldisilazane was given, A preferable minimum is 5 nm and a preferable upper limit is 20 nm. If it is less than 5 nm, the silica particles are buried in the toner particle surface, and a sufficient effect may not be obtained.
If it exceeds 0 nm, the toner particles may not be sufficiently coated.
Further, when the silica particles that have been subjected to the surface treatment with hexamethyldisilazane adhere to the surface of the toner particles, the silica particles aggregate to form a silica aggregate. A preferable lower limit of the size of the silica aggregate is 0.1 μm, and a preferable upper limit is 0.5 μm.

The method of surface treatment with hexamethyldisilazane is not particularly limited.For example, while stirring silica powder using a blender or the like, hexamethyldisilazane is mixed with tetrahydrofuran (THF), toluene, ethyl acetate, methyl ethyl ketone or acetone. A dilute solution diluted with a solvent can be added dropwise or sprayed, mixed well, and the resulting mixture is placed in an oven, heated and dried.

Although there is no particular limitation on the method of attaching the silica particles that have been surface-treated with hexamethyldisilazane to the surface of the toner particles, for example, silica particles that have been surface-treated with hexamethyldisilazane are applied to the toner particles. Appropriate amount can be added, and it can carry out by the method etc. which mix using a meteor type stirrer, a homogenizer, a mechanochemical stirrer, a fluid mixer, etc. In this specification, adhesion means that toner particles and silica particles come into contact with each other and stick to each other. Specifically, for example, in addition to physical adsorption or the like, chemical bonds such as ionic bonds, or those due to interactions by hydrophobic interactions can be mentioned.

The silica particles that have been surface-treated with hexamethyldisilazane may be attached to the toner particles alone or in combination with silica particles that have been surface-treated with other substances. Moreover, you may make it adhere together and use together with the particle | grain larger than the primary particle of the silica particle to which the surface treatment by the said hexamethyldisilazane was given.

The preferable lower limit of the content of the silica particles surface-treated with hexamethyldisilazane is 0.1 part by weight with respect to 100 parts by weight of the toner, and the preferable upper limit is 3 parts by weight.
If the amount is less than 0.1 parts by weight, the effects of improving the fluidity and improving the charging characteristics cannot be sufficiently exhibited. If the amount exceeds 3 parts by weight, the toners may aggregate.

Using the toner resin composition as a binder resin, if necessary, a toner resin comprising a release agent, a colorant, a charge control agent, a magnetic material, a rubbery polymer, and a styrene-acrylate copolymer, A toner can be manufactured by mixing with a carrier, a cleaning property improving agent, and the like. Such a toner is also one aspect of the present invention.

The release agent is not particularly limited, and examples thereof include olefin waxes such as polypropylene wax, polyethylene wax, microcrystalline wax, and oxidized polyethylene wax, and paraffin waxes; fats such as carnauba wax, sazol wax, and montanic ester wax. Desaturated carnauba wax; Saturated aliphatic acid wax such as baltimic acid, stearic acid, and montanic acid; Unsaturated aliphatic acid wax such as pracidic acid, eleostearic acid, and valinalic acid; Stearyl alcohol; Saturated alcohols and aliphatic alcohols such as aralkyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, and melyl alcohol; polyhydric alcohols such as sorbitol Saturated fatty acid amide waxes such as linoleic acid amide, oleic acid amide, lauric acid amide; saturated fatty acid bisamides such as methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, hexamethylene bisstearic acid amide Wax; Unsaturated acid amide wax such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearin Aromatic bisamide waxes such as acid amides and N, N′-distearylisophthalic acid amides; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate; vinyl monomers such as styrene and acrylic acid Graft-modified wax obtained by graft polymerization of mer to polyolefin; Partial ester wax obtained by reacting fatty acid such as behenic monoglyceride with polyhydric alcohol; Methyl ester wax having hydroxyl group obtained by hydrogenating vegetable oil; Examples thereof include ethylene-vinyl acetate copolymer waxes having a high component content; long-chain alkyl acrylate waxes such as saturated stearyl acrylate waxes such as acrylic acid; aromatic acrylate waxes such as benzyl acrylate waxes. Of these, long-chain alkyl acrylate waxes and aromatic acrylate waxes are preferred because they are highly compatible with the toner resin composition and provide a highly transparent toner. These release agents may be used alone or in combination of two or more, but it is particularly preferable to use in combination of two or more release agents having a melting point of 30 ° C. or more.
The size of the release agent in the toner is not particularly limited, but the major axis is preferably 2 μm or less.

The colorant is not particularly limited. For example, carbon black such as furnace black, lamp black, thermal black, acetylene black, channel black, aniline black, phthalocyanine blue, quinoline yellow lamp black, rhodamine-
B, azo pigment, perylene pigment, perinone pigment, anthraquinone pigment, dioxazine pigment, isoindoline pigment, isoindolinone pigment, selenium pigment, indico pigment, quinophthalone, diketopyrrolopyrrole, quinacridone, etc. Is mentioned.
The preferred lower limit of the blending amount of these colorants is usually 1 part by weight with respect to 100 parts by weight of the toner resin composition, and the preferred upper limit is 10 parts by weight.

There are two types of charge control agents, positive charge and negative charge. Examples of the charge control agent for positive charge include nigrosine dyes, ammonium salts, pyridinium salts, and azines. Examples of the charge control agent for negative charge include chromium complexes and iron complexes. Among these, an acid-modified charge control agent is suitable, and when it is salicylic acid-modified, it crosslinks with the toner resin composition and develops rubber elasticity. Metal complexes of alkyl-substituted salicylic acid such as di-tert-butylsalicylic acid chromium complex and di-tert-butylsalicylic acid zinc complex are preferable because they are colorless or light-colored and do not affect the color tone of the toner. As the charge control agent, a charge control resin (CCR) can also be suitably used. As the charge control resin, for example,
Examples thereof include a styrene acrylic polymer obtained by copolymerization of a monomer containing a quaternary ammonium salt, an organic fluorine-based monomer, a sulfonic acid group-containing monomer, a phenylmaleimide monomer, and the like.
The preferred lower limit of the amount of these charge control agents is usually 0.1 parts by weight with respect to 100 parts by weight of the toner resin composition, and the preferred upper limit is 10 parts by weight.

As said magnetic body, brand name "TAROX BL series" (made by a titanium industry company), for example
, Product name "EPT series", product name "MAT series", product name "MTS series" (
All are made by Toda Kogyo Co., Ltd.), trade name "DCM series" (made by Dowa Iron Powder Co., Ltd.), trade name "KBC"
Series ”, product name“ KBI series ”, product name“ KBF series ”, product name“ KBP series ”(all manufactured by Kanto Denka Kogyo Co., Ltd.), product name“ Bayoxide E series ”(B
ayer AG).

Examples of the rubbery polymer include natural rubber, polyisoprene rubber, polybutadiene rubber, nitrile rubber (acrylonitrile-butadiene copolymer), chloroprene rubber, butyl rubber, acrylic rubber, polyurethane elastomer, silicone rubber, and ethylene-propylene copolymer. , Ethylene-propylene-diene copolymer, chlorosulfinated polyethylene, ethylene vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, chlorinated polyethylene, epichlorohydrin rubber, nitrile isoprene Synthetic rubber such as rubber, elastomer such as polyester elastomer, urethane elastomer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, steel Down - ethylene butylene - styrene block copolymer, styrene - ethylene propylene - block copolymer of an aromatic hydrocarbon and a conjugated diene hydrocarbon such as styrene block copolymers. The block copolymer contains styrene
A butadiene block copolymer, a styrene-isoprene block copolymer, or the like may be mixed, or these hydrogenated products may be mixed.
Further, a rubbery polymer comprising a block copolymer of an aromatic hydrocarbon having a polar group such as a hydroxyl group, a carboxyl group, an aldehyde group, a sulfonyl group, a cyano group, a nitro group, or a halogen group and a conjugated diene is used as a toner. It is preferable because of its excellent affinity with. These block copolymers having polar groups at the ends can be obtained by living polymerization.
The rubbery polymer can improve the resin strength of the resin contained in the toner. Therefore, the toner containing the rubber-like polymer can prevent the filming phenomenon of the toner, and a toner suitable for the non-magnetic one-component toner requiring high resin strength can be obtained.

Examples of the carrier include simple metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, and rare earth, alloys, oxides, and ferrites. The surface of the carrier may be oxidized. Carrier surface is polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone polymer, polyester, metal complex of di-tert-butylsalicylic acid, styrene polymer, acrylic polymer, polyamide, polyvinyl butyral, nigrosine base May be coated with a functional dye, silica powder, alumina powder or the like. By coating the carrier, preferable triboelectric chargeability can be imparted to the carrier.

The toner of the present invention preferably has a peak at a position where the weight average molecular weight is 2000 or less when measured by gel permeation chromatography. This improves the fixability. The toner of the present invention preferably has a peak at a position where the weight average molecular weight is 10,000 or more when measured by gel permeation chromatography. Thereby, water resistance improves.

The particle size of the toner of the present invention is not particularly limited, but particularly high image quality can be obtained when it is 5 μm or less.
The moisture content of the toner of the present invention is not particularly limited, but the preferred lower limit is 0.01% by weight.
The preferred upper limit is 0.2% by weight. If it is less than 0.01% by weight, production becomes difficult due to problems in production, and if it exceeds 0.2% by weight, sufficient charging stability may not be obtained.
The repose angle of the toner of the present invention is not particularly limited, but the preferred lower limit of the repose angle at 23 ° C. and 60% humidity is 1 degree, and the preferred upper limit is 30 degrees. If it is less than 1 degree, handling of the toner may be difficult, and if it exceeds 30 degrees, the fluidity of the toner may be insufficient. The angle of repose of the toner can be measured by, for example, a powder tester (for example, PT-N type manufactured by Hosokawa Micron Corporation).

The surface roughness of the toner of the present invention is not particularly limited, but the preferred lower limit is 0.01 μm,
A preferred upper limit is 2 μm. If it is less than 0.01 μm, it may be difficult to perform printing, and if it exceeds 2 μm, the surface gloss of the resulting image may be insufficient. In addition, the surface roughness indicates the printing portion of an image printed using the toner of the present invention according to JIS B 060.
1 can be measured by a method defined as a method for measuring the arithmetic average roughness (Ra).

When the toner of the present invention is used for an application that is particularly required to have excellent surface gloss, the preferred lower limit of the melt viscosity at 150 ° C. is 100 mPa ·
s, and a preferable upper limit is 50,000 mPa · s. If it is less than 100 mPa · s, the storage stability may be inferior, and if it exceeds 50,000 mPa · s, sufficient surface gloss may not be obtained. A more preferable upper limit is 10,000 mPa · s.

The toner of the present invention can exhibit good fixability in a wide range from low temperature to high temperature, and is excellent in low-temperature fixability, high-temperature offset resistance and blocking resistance, so that printing can be performed after the switch is turned on. Since the time until the image is shortened can be shortened, it is economical. Further, even when the temperature of the roller is lowered, the clearness of the image can be maintained, so that the printing speed can be increased. Since the toner of the present invention is colorless and transparent, a desired color can be easily adjusted.
In addition, since the toner of the present invention is excellent in fluidity, the toners do not aggregate with each other, and it becomes difficult for the toner to adhere to the cleaning blade, and the toner can be stably supplied to the developing roller and the like. Furthermore, since the toner of the present invention is excellent in charging characteristics, good image quality can be obtained.

The toner of the present invention may be fixed by a fixing roller to which a release oil is applied, but can exhibit good fixability even if the release oil is not applied to the fixing roller.
In addition, the crystalline polymer and non-crystalline polyester used in the above resin composition for toner exhibit good fixability in a wide range from low to high temperatures without crosslinking or blending with a high molecular weight resin. In other words, it is possible to obtain a toner excellent in both low-temperature fixability, high-temperature offset resistance, and blocking resistance. A toner using such a resin composition for a non-crosslinked toner is more easily pulverized than a toner using a toner resin containing a high molecular weight resin, exhibits sharp melting characteristics, and provides a glossy fixed image. .

According to the present invention, it is possible to provide a toner that is excellent in low-temperature fixability, high-temperature offset resistance and blocking resistance, can perform good color development, and has excellent fluidity and charging characteristics.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Example 1)
(1) Manufacture of polybutylene terephthalate (PBT) A distillation column, a water separator, a nitrogen gas inlet tube, a thermometer and a stirring measure are installed in a conventional manner in a 60 L reaction vessel, and a dicarboxylic acid component is added under a nitrogen gas atmosphere. As 100 moles of terephthalic acid,
120 mol of 1,4-butanediol was added as a diol component, 0.05 mol of titanium tetrabutoxide (TBB) was charged as an esterification condensation catalyst, and the ester produced while distilling water and methanol produced at 200 ° C. from a distillation column. The reaction was carried out. The esterification reaction was completed when water and methanol no longer distilled from the distillation column.
After completion of the esterification reaction, the opening to the distillation column of the 60 L reaction vessel is closed, the line from the vacuum pump is opened, the pressure in the reaction system is reduced to 5 mmHg or less, 240 ° C., stirring speed 6
A condensation reaction was carried out at 0 rpm and the free diol produced by the condensation reaction was distilled out of the reaction system to obtain polybutylene terephthalate.

(2) Production of non-crystalline polyester A distillation column, a water separator, a nitrogen gas inlet tube, a thermometer and a stirrer are installed in a conventional manner in a 60 L reaction vessel, and terephthalate is used as a dicarboxylic acid component in a nitrogen gas atmosphere. 90 moles of acid, 5 moles of phthalic anhydride, 5 moles of isophthalic acid, 60 moles of neopentyl glycol as a branched monomer component, 60 moles of ethylene glycol as other diols, 0.05 mole of titanium tetrabutoxide (TBB) as an esterification condensation catalyst The esterification reaction was carried out at 200 ° C. while distilling water and methanol produced from the distillation column. The esterification reaction was completed when water and methanol no longer distilled from the distillation column.
After completion of the esterification reaction, the opening to the distillation column of the 60 L reaction vessel is closed, the line from the vacuum pump is opened, the pressure in the reaction system is reduced to 5 mmHg or less, 240 ° C., stirring speed 6
A condensation reaction was performed at 0 rpm, and free diol generated by the condensation reaction was distilled out of the reaction system to obtain an amorphous polyester.

(3) Production of toner After 7.5 parts by weight of the obtained polybutylene terephthalate and 92.5 parts by weight of non-crystalline polyester were melt-kneaded at 240 ° C. using a twin screw extruder, they were rapidly cooled using a belt cooler, A resin composition for toner was obtained.
100 parts by weight of the obtained resin composition for toner, 3 parts by weight of carnauba wax, a charge control agent (S
-34: manufactured by Orient Chemical Co., Ltd. 1 part by weight and 5 parts by weight of carbon black were sufficiently mixed with a Henschel mixer, and then melt-kneaded at 120 ° C, cooled and coarsely pulverized. Then, it is finely pulverized with a jet mill (Lab Jet: manufactured by Nippon Pneumatic Co., Ltd.), and the average particle size is about 8-12 μm.
Toner powder was obtained. Further, the toner powder was classified by a classifier (MDS-2: manufactured by Nippon Pneumatic Co., Ltd.) to obtain toner particles having an average particle diameter of about 10 μm.

Silica particles (RX) surface-treated with hexamethyldisilazane were added to 100 parts by weight of toner particles.
200: manufactured by Nippon Aerosil Co., Ltd., 1 part by weight (primary particle size: 12 nm) was added, and the mixture was uniformly mixed using a stirrer to produce a toner.

(Example 2)
In the production of toner, silica particles surface treated with hexamethyldisilazane (RX20
0: 0.5 parts by weight of Nippon Aerosil Co., Ltd., primary particle size 12 nm) and 1 part by weight of silica particles surface-treated with dimethyldichlorosilane (R974: Nihon Aerosil Co., Ltd., primary particle size 12 nm) are added. A toner was obtained in the same manner as in Example 1 except that.

(Comparative Example 1)
In toner production, silica particles (R974) surface-treated with dimethyldichlorosilane are used.
A toner was obtained in the same manner as in Example 1 except for adding 1.5 parts by weight of Nihon Aerosil Co., Ltd. (primary particle size: 12 nm).

(Evaluation)
The toners produced in Examples 1 and 2 and Comparative Example 1 were evaluated by the following methods.
The results are shown in Table 1.

[Measurement of molecular weight and molecular weight distribution]
(1) As a crystalline polyester GPC measurement device, HTR-C manufactured by Nihon Millipore Ltd. is used, and HFIP-806M (2) manufactured by Showa Denko KK is connected in series to the column, and the weight average molecular weight is determined. It was measured. The measurement conditions were a temperature of 40 ° C., a sample of 0.1 wt% hydroxyfluoroisopropanol (HFIP) solution (passed through a 0.45 μm filter), and an injection amount of 100
As a carrier solvent, HFIP containing 0.68 g of TFA per liter was used as a carrier solvent. Standard polystyrene was used as a calibration sample.
(2) As a non-crystalline polyester GPC measurement apparatus, HTR-C manufactured by Nippon Millipore Limited was used, and KF-800P (1), KF-806M (2), KF- manufactured by Showa Denko K.K. 802.5 (1
Were used in series, and the weight average molecular weight was measured. The measurement condition is that the temperature is 40 ° C.
The sample used was a 0.2 wt% THF solution (passed through a 0.45 μm filter), the injection amount was 100 μL, the carrier solvent was THF, and standard polystyrene was used as a calibration sample.

[Measurement of glass transition temperature (Tg)]
After holding at a temperature equal to or higher than the melting point for a while, quenching was performed to prepare a sample in which crystallization was completely suppressed. About this sample, a differential scanning calorimeter (manufactured by Seiko Denshi Kogyo, DSC-6)
200R) at a rate of temperature increase of 10 ° C./min, according to JIS K 7121,
The intermediate glass transition temperature described in the standard (9.3 “How to determine the glass transition temperature”) was determined.

[Measurement of crystal melting point (Tm) and endotherm]
Using a differential scanning calorimeter (DSC-6200R, manufactured by Seiko Denshi Kogyo Co., Ltd.), the heating rate was 10
10 mg of the sample was heated at 0 ° C./min and measured according to JIS K 7121, and the standard (9
. 1 “How to find the melting temperature”), the melting peak value is obtained and the crystal melting point Tm
In addition, the endothermic amount at the crystal melting point Tm was determined from the DSC7 chart.

[Evaluation of fluidity]
On a powder tester (manufactured by Hosokawa Micron Co., Ltd.), 60, 100, and 200 mesh sieves were set in three layers in order from the top. After measuring the tare weight of each sieve in advance, 100 g of toner was placed on a 60 mesh sieve and vibrated for 10 seconds. Thereafter, the weight of each sieve was measured, and the toner residual ratio was calculated from the following formula (3) and used for evaluation of fluidity.

[Evaluation of charging characteristics]
The charge amount is measured using a blow-off type charge amount measuring device (manufactured by Toshiba Chemical Corporation), and the specific charge Q
The charging characteristics were evaluated by obtaining / m.
To measure the charge amount, first, a toner used for measurement and a ferrite carrier having an average particle diameter of 60 μm were mixed at a weight ratio of 6.5: 93.5 to prepare a two-component developer. 50 g of the obtained two-component developer was weighed into 100 mL of polybin and mixed for 5 minutes using a mix rotor. After mixing, 0.2 g of the two-component developer was placed in a brass measuring cell equipped with a 400 mesh stainless steel mesh. Next, the blow pressure regulator was blown at a blow pressure of 1.0 kg / cm ² for 30 seconds to remove only the toner from the cell. The two-component developer and the measurement chamber were adjusted to a temperature of 23 ° C. and a relative humidity of 55% for 24 hours.
At this time, 3 times from the start of blowing is measured by using a blow-off type charge amount measuring device.
The electric capacity after 0 seconds is obtained, and when the electric capacity value is C (μC), the specific charge Q of the toner
/ M (μC / g) can be calculated by the following formula (4). M represents the weight of toner contained in 0.2 g of the two-component developer.
Q / m = C / m = C / (0.2 × 6.5 / 100) = C / 0.013 (4)

[Evaluation of blocking properties]
Take 10 g of toner in a 100 mL sample bottle, leave it in a thermostatic bath at 50 ° C. for 8 hours, and then screen with a 250 μm filter using a powder tester (manufactured by Hosokawa Micron) to observe whether aggregates remain on the filter. When there was an aggregate, the weight (% by weight) of the aggregate with respect to the toner weight was determined.

[Filming evaluation]
After 10,000 sheets were printed, whether the toner adhered to the fixing roller was visually observed. If no toner adhered, the film was evaluated as having no filming.

[Measurement of high temperature offset temperature and low temperature offset temperature]
A developer was prepared by mixing 6.5 parts by weight of toner with 93.5 parts by weight of an iron powder carrier having an average particle size of 50 to 80 μm. As an electrophotographic copying machine, a UBIX4160AF manufactured by Konica was used so that the set temperature of the heat fixing roller could be changed up to 250 ° C.
The set temperature of the heat fixing roller was changed stepwise to obtain a copy in which the unfixed toner image was fixed on the transfer paper by the heat fixing roller at each set temperature.
It was observed whether the blank portion of the obtained copy and the fixed image were stained with toner, and a temperature region where no contamination occurred was defined as a non-offset temperature region. Further, the maximum value in the non-offset temperature region was set as the high temperature offset temperature, and the minimum value was set as the low temperature offset temperature.

[Measurement of minimum fixing temperature of toner]
Copying was performed by changing the set temperature of the heat fixing roller of the electrophotographic copying machine step by step, and the blank portion and the fixed image were not stained with toner without causing the fog on the blank portion and the fixed image. When the fixed image of the copy was rubbed with a sand eraser for typewriter, the case where the decrease in the density of the fixed image was less than 10% was judged as good fixing, and the minimum temperature at that time was determined.
The image density was measured using a Macbeth photometer.

As shown in Table 1, the toners produced in Examples 1 and 2 were excellent in fluidity, charging characteristics and fixability. On the other hand, although the toner prepared in Comparative Example 1 was externally added with surface-treated silica particles, the fluidity was low and the fixability was poor.

According to the present invention, it is possible to provide a toner that is excellent in low-temperature fixability, high-temperature offset resistance and blocking resistance, can perform good color development, and has excellent fluidity and charging characteristics.

Claims (2)

Toner particles containing a resin composition for toner containing a crystalline polymer having a melting point of 180 to 280 ° C. and an amorphous polyester having a glass transition temperature of 30 to 80 ° C., and adhered to the surface of the toner particles A toner comprising the silica particles, wherein the silica particles are surface-treated with hexamethyldisilazane. The content of silica particles that have been surface treated with hexamethyldisilazane is 100%
The toner according to claim 1, wherein the amount is 0.1 to 3 parts by weight with respect to parts by weight.