JP7077116B2 - Toner and external additive for toner - Google Patents

Description

The present invention relates to toners used in electrophotographic methods, electrostatic recording methods, magnetic recording methods, etc., and external additives for toners.

In recent years, electrophotographic devices have been pursued to be faster and have a longer life. Furthermore, there is still a high demand for energy saving, and various proposals have been made to achieve both excellent durability and low temperature fixing performance in toner.

For example, Patent Document 1 describes an invention in which a core-shell type composite fine particle in which the surface of a resin fine particle is coated with silica is used as an external additive.
Further, in Patent Document 2, crystalline polyester is added to the toner base to improve the sharp melt performance, thereby improving the low temperature fixability.
Further, Patent Document 3 proposes a toner having a crystalline polyester on the surface of the parent particles.
Further, Patent Document 4 proposes a toner having composite fine particles in which inorganic fine particles are embedded in resin fine particles having a melting point of 60 ° C. or higher and 150 ° C. or lower on the surface of the toner. It is considered that this method can improve the meltability of the surface layer (near the surface) of the toner and obtain a constant development performance.

Japanese Unexamined Patent Publication No. 2012-013776 JP-A-2015-007765 Japanese Unexamined Patent Publication No. 2004-221740 Japanese Unexamined Patent Publication No. 2015-045859

The invention of Patent Document 1 certainly has an effect on the physical properties that contribute to development, such as the chargeability and fluidity of the toner. However, as a trade-off, there is a problem that low temperature fixing property is hindered.
Further, in Patent Document 2, since the low temperature fixing performance depends only on the viscosity of the base material, the deformation of the toner when receiving heat becomes large, so that the fixing unevenness according to the unevenness of the paper surface is likely to occur, and the image quality is high. Will lead to a decline in. Further, since the crystalline polyester plasticizes the entire toner, the toner tends to remain in a molten state even after being fixed, and the paper ejection adhesiveness in double-sided continuous printing becomes a big problem.
In the invention of Patent Document 3, although the meltability of the surface layer can be enhanced and the fixing unevenness can be suppressed, the presence of crystalline polyester on the surface layer of the toner improves the chargeability, fluidity, and environmental characteristics of the toner at high temperature and high humidity. The harmful effects of this are very large, and it is not sufficient in terms of compatibility with development.
In Patent Document 4, the convex portion of the inorganic fine particles generated by embedding may damage the parts in contact with the toner in the cartridge such as the developing sleeve and the photoconductor drum due to long-term use, and the durability of the entire cartridge is described. From the point of view, there are still issues. As described above, while further speedup and longevity are required, in order to solve the problems such as image quality and paper discharge adhesion that accompany it, the durability of the toner is maintained and the surface layer melting performance is maintained. We have to think about improvement. There is a trade-off between the toner durability performance and the surface melting performance, and it is considered that there is still room for improvement in eliminating this trade-off.

An object of the present invention is to provide a toner capable of solving the above problems.
Specifically, it is a toner that has high development performance and image quality even if the surface melting performance is high, and exhibits good durability performance including not only the toner but also cartridge parts such as a developing sleeve and a photoconductor drum. In other words, we provide toner that eliminates the trade-off between melting performance and durability performance near the surface of the toner, and simultaneously achieves high speed, long life, suppression of paper ejection, and improvement of image quality, and an external additive for toner. It is to be.

The present invention is a toner having a toner particle having a binder resin and a colorant, and an external additive.
The external preparation is
With a core containing organic matter,
The coating layer of the organosilicon polymer on the surface of the core and
It is a core-shell type composite particle with
The softening point (Tm) of the organic substance is 50 ° C. or higher and 105 ° C. or lower.
The organosilicon polymer is a polymer of a polymerizable silane coupling agent.
The softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
The amount of change (dE') of the toner storage elastic modulus E'with respect to the temperature T based on the temperature T [° C.]-Toner storage elastic modulus E'[Pa] curve obtained by the powder dynamic viscoelasticity measurement of the toner. When the curve of / dT) is obtained,
The change amount (dE'/ dT) curve has a minimum value of −1.00 × ¹⁰⁸ or less between the onset temperature and 90 ° C., and the minimum value on the lowest temperature side is the minimum value. It relates to a toner characterized by being 1.35 × ¹⁰⁸ or less.
Further, the present invention is a toner having a toner particle having a binder resin and a colorant, and an external additive.
The external preparation is
With a core containing crystalline polyester resin,
A coating layer containing an organosilicon polymer on the surface of the core, and
It is a core-shell type composite particle with
The softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
The softening point (Tm) of the crystalline polyester resin is 50 ° C. or higher and 105 ° C. or lower.
The present invention relates to a toner , wherein the organosilicon polymer is a polymer of a polymerizable silane coupling agent .
Further, the present invention is an external additive for toner which is a core-shell type composite particle having a core containing a crystalline polyester resin and a coating layer containing an organic silicon polymer on the surface of the core.
The softening point (Tm) of the crystalline polyester resin is 50 ° C. or higher and 105 ° C. or lower.
The organosilicon polymer is a polymer of a polymerizable silane coupling agent.
The number average particle size Dn measured by the dynamic light scattering method of the composite particles is 50 nm or more and 300 nm or less.
The present invention relates to an external additive for toner, wherein the ratio Dv / Dn of the volume average particle size Dv of the composite particles to the Dn is 2.0 or less.

According to the present invention, the trade-off between the melting performance and the durability performance near the surface of the toner is eliminated, and the speed / life is extended, the paper ejection is suppressed, and the image quality is improved at the same time. Agents can be provided.

Temperature T [° C] -toner storage elastic modulus E'[Pa] curve by powder dynamic viscoelasticity measurement Temperature T [° C] -change amount dE' / dT [Pa / ° C] curve, and temperature T [° C] -toner storage elastic modulus G'[Pa] curve in dynamic viscoelasticity measurement FT-IR spectrum of crystalline resin 1

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.
As mentioned earlier, eliminating the trade-off between melting performance and durability performance near the surface of the toner is technically a high hurdle. When trying to ensure the durability of the toner, it is effective to add a spacer of inorganic particles to the surface of the toner particles. However, the addition of such a large amount of spacer particles inhibits the melting of the toner particle matrix at the time of fixing and adversely affects the low temperature fixing performance. Therefore, in order to promote melting at the time of fixing, there is a method of reducing the viscosity of the entire matrix by adding a plasticizer such as crystalline polyester to the toner particle matrix.
However, if the melting at the time of fixing depends on the viscosity of the toner particle matrix, it may cause a remarkable deterioration in image quality. If the matrix viscosity at the time of fixing is low, the deformation of the toner particles when heat is received from the fixing heat roller increases accordingly, so that the toner transferred to the convex portion of the paper surface that receives a large amount of heat from the fixing heat roller , The melting unevenness, that is, the fixing unevenness between the toners transferred to the recesses that do not receive much heat tends to increase. This fixing unevenness becomes a density unevenness on the image and becomes apparent, causing a remarkable deterioration in image quality.

That is not the only problem when the melting at the time of fixing depends on the viscosity of the mother body. When the melting depends on the viscosity of the toner particle matrix, the entire toner particles are melted at the time of fixing, so that the molten state can be easily maintained on the paper even after the fixing. As a result, the problem of paper ejection adhesion, in which the ejected papers stick to each other during double-sided printing, is likely to occur.
In order to prevent such fixing unevenness and paper ejection adhesion while maintaining good low-temperature fixing property, it is necessary to consider melting at the time of fixing, which does not depend only on the viscosity of the toner particle matrix. Specifically, it is important to improve the melting performance near the surface of the toner. When the toner is heated by the fixing heat roller, if the vicinity of the toner surface melts, the space between the paper surface and the toner and the space between the toner and the toner are adhered, and the toner can be fixed on the paper surface. At that time, if the toner particle base has elasticity of a certain level or more with respect to heat, the deformation of the toner particles can be minimized. That is, it is possible to suppress fixing unevenness while maintaining good low-temperature fixing.

Further, when only the vicinity of the toner surface is melted, since there are few melted portions in the entire toner particles, it is possible to quickly solidify the toner on the paper after fixing. As a result, the toner is less likely to cause paper ejection adhesion.
Further, even in the present situation where high print speed is required, the melting performance near the surface of the toner is very important. As the speed of printing increases, it is naturally necessary to increase the speed of the fixing process. That is, it means that the speed of the paper passing through the fixing heat roller becomes faster. The faster the paper passes through, the less time it takes to receive heat from the heat roller, and as a result, it becomes difficult to distribute a sufficient amount of heat to the inside of the toner particles during fixing. When the melting at the time of fixing depends on the viscosity of the toner particle matrix, the effect cannot be fully utilized in the high-speed fixing system. On the other hand, if melting performance is provided near the surface of the toner, it is expected that the melting reaction to heat will be faster, so even in a high-speed fixing system, the potential can be fully demonstrated. It is possible.

However, it is not easy to obtain good melting performance near the surface. Of course, it is possible to promote surface melting if the surface has a substance that plasticizes the toner particle matrix, such as crystalline polyester or low melting point wax. However, since such a plasticizer has poor chargeability and fluidity, when it is present in the vicinity of the toner surface, there is a great demerit in toner transportability and developability.
As a result of repeated studies in the face of the above problems, the present inventors have found that the toner having the above configuration can achieve both good melting performance near the toner surface and durability performance. That is, according to the present invention, it is possible to obtain a toner which has excellent low-temperature fixing property and durability performance in a high-speed machine, has less fixing unevenness, and suppresses paper ejection.

Specifically, the present inventors
A toner having toner particles having a binder resin and a colorant and an external additive.
The external additive is a core-shell type composite particle having a core containing an organic substance and a coating layer of an organosilicon polymer on the surface of the core.
The softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
The amount of change (dE') of the toner storage elastic modulus E'with respect to the temperature T based on the temperature T [° C.]-Toner storage elastic modulus E'[Pa] curve obtained by the powder dynamic viscoelasticity measurement of the toner. When the curve of / dT) is obtained,
The change amount (dE'/ dT) curve has a minimum value of −1.00 × ¹⁰⁸ or less between the onset temperature and 90 ° C., and the minimum value on the lowest temperature side is the minimum value. It has been found that by using a toner having a characteristic of −1.35 × ¹⁰⁸ or less, it is possible to achieve both melting performance and durability performance in the vicinity of the toner surface.
Further, the present inventors are toners having toner particles having a binder resin and a colorant, and an external additive.
The external additive includes a core containing a crystalline polyester resin, a coating layer containing an organosilicon polymer on the surface of the core, and the like.
It is a core-shell type composite particle with
The softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
It was found that even by using a toner characterized in that the softening point (Tm) of the crystalline polyester resin is 50 ° C. or higher and 105 ° C. or lower, both melting performance and durability performance in the vicinity of the toner surface can be achieved.

In the present invention, the amount of change in the toner storage elastic modulus E'with respect to the temperature T based on the temperature T [° C.]-Toner storage elastic modulus E'[Pa] curve obtained by the powder dynamic viscoelasticity measurement of the toner. When the curve of (dE'/ dT) is obtained, the change amount (dE' / dT) curve has a minimum value of -1.00 × ¹⁰⁸ or less between the onset temperature and 90 ° C. However, it is very important that the minimum value on the lowest temperature side among the minimum values is −1.35 × ¹⁰⁸ or less. In addition, it is also important that the softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
In this powder dynamic viscoelasticity measurement, it is possible to measure the viscous elasticity of the toner in the powder state, and the storage elastic modulus E'[Pa] indicated by this measurement is that the toner behaves as a powder. The inventors think that it indicates the state of toner melting at that time.

FIG. 1 shows an example of a temperature T [° C.]-Toner storage elastic modulus E'[Pa] curve in the powder dynamic viscoelasticity measurement of the toner of the present invention. According to FIG. 1, when the storage elastic modulus with respect to the temperature of the toner is measured in the powder dynamic viscoelasticity measurement, it can be seen that the storage elastic modulus decreases in two steps. The present inventors consider that the reason for the two stages is that the melting of the toner particles near the surface and the melting of the entire toner occur at different points.
When the toner receives heat from the outside, it naturally receives heat first near the toner surface, so the decrease in storage elastic modulus shown on the low temperature side means the progress of melting near the toner surface. It is presumed to be. Further, when the softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower, it means that the melting of the toner particles does not proceed so much between the onset temperature and 90 ° C., which is shown on the low temperature side. It is presumed that the decrease in the storage elastic modulus is the progress of melting in the vicinity of the toner surface due to the external additive. The softening point of the toner particles is preferably 100 ° C. or higher and 150 ° C. or lower. Further, the rate of decrease in storage elastic modulus with respect to temperature means the rate of toner melting.
Therefore, the change of the toner storage elastic modulus E'with respect to the temperature T based on the "temperature T [° C.]-toner storage elastic modulus E'[Pa] curve obtained by the powder dynamic viscoelasticity measurement" defined here. When the amount (dE'/ dT) curve is obtained, the minimum value at which the change amount (dE' / dT) curve becomes -1.00 × ¹⁰⁸ or less between the onset temperature and 90 ° C. is set. It is considered that the "minimum value on the lowest temperature side of the minimum values" indicates the potential of the melting performance near the surface of the toner. The smaller this value, that is, the larger the absolute value, the higher the melting performance of the toner near the surface.
In order to have good melting performance, it is necessary that the value of this minimum value is -1.35 × ¹⁰⁸ or less, preferably -1.80 × ¹⁰⁸ or less, and more preferably −2.00. It is × ¹⁰⁸ or less. On the other hand, the lower limit is not particularly limited, but is preferably −9.5 × ¹⁰⁸ or more, and more preferably −8.0 × ¹⁰⁸ or more. The minimum value can be controlled by the amount of composite particles added, the softening point, the type of organic substance, and the like. If it is desired to reduce the minimum value, the use of composite particles having a low softening point, the use of a crystalline material as an organic substance, and the like can be mentioned.

Further, it is very important that the external additive used in the present invention is a core-shell type composite particle having a core containing an internal organic substance and a coating layer made of an organosilicon polymer on the surface of the core.
If an organic substance is simply added, the demerits in the durability and developability of the toner are very large. Further, if a large amount of an inorganic substance is simply externally added, it becomes a factor that hinders melting in the vicinity of the surface of the toner at the time of fixing, and in the present situation where the printing speed is increased, sufficient low temperature fixing property cannot be obtained.
However, by coating the surface of the core with an organosilicon polymer, that is, by having a coating layer of the organosilicon polymer on the surface layer of the core containing an organic substance, good durability and good durability can be maintained while maintaining the melting performance near the surface of the toner. It is possible to ensure developability.

Furthermore, various merits are produced by having a core-shell structure in which an organosilicon polymer forms a coating layer, rather than simply having inorganic particles on the core surface.
One of the merits is the effect on paper discharge adhesion. The mechanism is considered as follows. When the organosilicon polymer forms a coating layer, silicon is present on the surface of the core containing the organic matter as a surface rather than a point. As a result, when the toner is melted on the paper at the time of fixing, this coating layer acts as a crystal nucleating agent or an inorganic filler, and it is considered that there is an effect of increasing the viscosity of the toner on the paper after fixing. On the other hand, when the core surface containing an organic substance has inorganic particles, the inorganic particles are present only at points, so that the effect as a crystal nucleating agent or an inorganic filler is considered to be very slight.
Further, since the organosilicon polymer forms a coating layer, the hardness of the entire composite particle is increased, and the composite particle effectively acts as a spacer particle. Therefore, the durable developability of the toner is improved.

As a further effect, the effect of suppressing the polishing of the cartridge member can be considered. Since the organosilicon polymer forms a coating layer, it is presumed that the surface of the composite particles is smooth, and the cartridge members such as the developing sleeve and the drum are not easily damaged. On the other hand, when the core surface containing an organic substance has inorganic particles, a relatively hard inorganic substance is present as a convex portion, so that the cartridge member such as a developing sleeve or a drum is easily damaged. If the developing sleeve or drum is scratched, streaks will be generated on the image and the durable developability will be reduced. Especially in high-speed developing equipment, the current situation becomes remarkable.

Further, when T _max is the temperature that is the minimum value on the lowest temperature side in the curve of the amount of change (dE' / dT) of E'with respect to the temperature T described above, the dynamic viscoelasticity when T _max is reached. It is preferable that the toner storage elastic modulus G'(T _max ) in the measurement is 2.50 × ¹⁰⁸ or more.
In the curve of the amount of change (dE'/ dT) of E'with respect to the temperature T, the minimum value on the lowest temperature side represents the melting performance potential near the toner surface, whereas G'represents the melting performance of the entire toner. The inventors are thinking. That is, the storage elastic modulus G'(T _ma ) when T _max is reached.
_x ) is the meltability of the entire toner at the point where melting in the vicinity of the toner surface progresses most. The higher the value, the more selectively the vicinity of the toner surface is melted, and the lower the value, the more the melting in the vicinity of the surface. It means that the performance depends on the melting of the toner particle base, that is, the melting of the entire toner.
As described above, in order to obtain good image quality and paper ejection adhesion performance, it is preferable that the vicinity of the surface is selectively melted. Further, since it does not depend on the melting of the toner particle base, the burial of the external additive due to the durability can be suppressed at the same time, so that the durability is also great. In order to obtain these effects, G'(T _max ) is preferably 2.50 × ¹⁰⁸ or more, more preferably 3.50 × ¹⁰⁸ or more, and further preferably 4.00 × 10 or more. ⁸ or more. On the other hand, the upper limit is not particularly limited, but is preferably 1.0 × 10 ¹⁰ or less, and more preferably 1.0 × 10 ⁹ or less. G'(T _max ) can be controlled by the softening point and the molecular weight of the toner particles.
FIG. 2 shows a temperature T [° C.]-change amount dE'/ dT [Pa / ° C.] curve and a temperature T [° C.]-Toner storage elastic modulus G'[Pa] curve in dynamic viscoelasticity measurement.

The organic substance of the core of the composite particle is not particularly limited, and examples thereof include amorphous resins such as polyester resin, vinyl resin, epoxy resin and polyurethane resin, and crystalline materials such as wax and crystalline polyester resin.
Further, considering the role of imparting good surface meltability to the toner, the softening point (Tm) of the organic substance inside is preferably 50 ° C. or higher and 105 ° C. or lower, and more preferably 50 ° C. or higher and 85 ° C. or lower.

The acid value of the organic substance in the core of the composite particle is preferably 4 mgKOH / g or more and 20 mgKOH / g or less, and more preferably 5 mgKOH / g or more and 19 mgKOH / g or less. When the acid value is in this range, more stable development performance can be obtained.

It is more preferable that the organic substance used for the core of the composite particle contains a crystalline polyester resin. When the organic substance contains a crystalline polyester resin, the plasticizing effect on the matrix is promoted, so that the melting performance in the vicinity of the toner surface is further improved. Further, since the organosilicon polymer near the surface acts as a crystal nucleating agent at the time of fixing and melting, the effect is further enhanced in the paper ejection adhesiveness. The organic substance may contain a known resin such as an amorphous polyester resin in addition to the crystalline polyester resin to the extent that the effect of the present invention is not affected. The organic substance is more preferably crystalline polyester. From the viewpoint of low-temperature fixing, the softening point (Tm) of the crystalline polyester resin is preferably 50 ° C. or higher and 105 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The crystallinity means that a clear endothermic peak is observed in the reversible specific heat change curve of the specific heat change measurement by the differential scanning calorimeter (DSC).

The weight average molecular weight (Mw) of the crystalline polyester resin inside the composite particles is preferably 18,000 or more and 50,000 or less, and more preferably 25,000 or more and 50,000 or less. By setting the weight average molecular weight (Mw) of the crystalline polyester resin to a desired range, the hardness as an external additive becomes appropriate and the durability is improved.

It is preferable that the crystalline polyester resin inside the composite particles has a urethane bond. Having a urethane bond increases elasticity at high temperatures. As a result, deformation of the toner when a large amount of heat is received during fixing can be suppressed, which is very effective in improving fixing unevenness.

Examples of the aliphatic diol that can be used for the synthesis of crystalline polyester include the following.
1,4-Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,
, 7-Heptane diol, 1,8-octane diol, 1,9-nonane diol, 1,10-decane diol, 1,11-undecane diol, 1,12-dodecane diol, 1,13-tridecane diol, 1 , 14-Tetradecanediol, 1,18-octadecanediol, 1,20-eicosandiol, etc. These can also be used alone or in combination. The aliphatic diol is not limited to these.
Further, as the aliphatic diol, an aliphatic diol having a double bond can also be used. Examples of the aliphatic diol having a double bond include the following. 2-Butene 1,4 diol, 3-Hexene 1,6 diol, 4-Octene 1,8 diol and the like.

Next, the acid component that can be used for the synthesis of crystalline polyester will be described. As the acid component, a polyvalent carboxylic acid such as an aliphatic dicarboxylic acid is preferable.
Examples of the aliphatic dicarboxylic acid include the following. Glyric acid, malonic acid, amber acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, 1,11-undecandicarboxylic acid, 1,12-dodecandicarboxylic acid, 1,13-Tridecandicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid. Alternatively, its lower alkyl or acid anhydride, etc. These can be used alone or in combination. Further, the aliphatic dicarboxylic acid is not limited to these.
Examples of the aromatic dicarboxylic acid include the following. Terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, etc. Of these, terephthalic acid is preferable because it is easily available and easily forms a polymer having a low melting point.
Further, as the acid component, a dicarboxylic acid having a double bond can also be used. Examples of such dicarboxylic acids include fumaric acid, maleic acid, 3-hexendioic acid, 3-octendioic acid and the like. Further, these lower alkyl esters and acid anhydrides can also be used. Of these, fumaric acid and maleic acid are preferable in terms of cost.

Examples of the isocyanate component for forming the urethane bond include the following. Aromatic diisocyanates having 6 or more and 20 or less carbon atoms (excluding carbons in NCO groups, the same applies hereinafter), aliphatic diisocyanates having 2 or more and 18 or less carbon atoms, alicyclic diisocyanates having 4 or more and 15 or less carbon atoms, and these diisocyanates. Modified products (modified products containing urethane group, carbodiimide group, allophanate group, urea group, burette group, uretdione group, uretoimine group, isocyanurate group, oxazolidone group; hereinafter also referred to as modified diisocyanate), and two or more of these. blend.

Examples of the aliphatic diisocyanate include the following. Ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate.
Examples of the alicyclic diisocyanate include the following. Isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate.
Examples of the aromatic diisocyanate include the following. m- and / or p-xylylene diisocyanate (XDI), α, α, α', α'-tetramethylxylylene diisocyanate.
Of these, aromatic diisocyanates having 6 to 15 carbon atoms, aliphatic diisocyanates having 4 to 12 carbon atoms, and alicyclic diisocyanates having 4 to 15 carbon atoms are particularly preferable, and HDI is particularly preferable. And IPDI, XDI. In addition to the above-mentioned diisocyanate, a trifunctional or higher functional isocyanate compound can also be used. The crystalline polyester is preferably a polymer of a condensate of an aliphatic diol and an aliphatic dicarboxylic acid and an isocyanate component. The content of the structure derived from the isocyanate compound in the crystalline polyester is 0.5 parts by mass or more and 40.0 parts by mass or less with respect to 100 parts by mass of the structure derived from the aliphatic diol and the aliphatic dicarboxylic acid. preferable.

The method for producing the crystalline polyester is not particularly limited, and the crystalline polyester can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. For example, depending on the type of monomer, direct polycondensation or transesterification method can be appropriately used for production.
The production of the crystalline polyester is preferably carried out at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower, and it is preferable to reduce the pressure in the reaction system as necessary to remove water and alcohol generated during condensation. ..
If the monomer dissolves or does not dissolve at the reaction temperature, it is preferable to add a solvent having a high boiling point as a dissolution aid to dissolve the monomer. The polycondensation reaction is carried out while distilling off the dissolution auxiliary solvent. When a monomer having poor compatibility is present in the copolymerization reaction, it is preferable to condense the monomer having poor compatibility with the monomer and an acid or alcohol to be polycondensed in advance, and then polycondensate with the main component.

Examples of catalysts that can be used in the production of crystalline polyester include titanium catalysts and tin catalysts. Examples of the titanium catalyst include, for example, titanium tetraethoxydo, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide and the like. Examples of tin catalysts include dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide and the like.

The content of organic matter in the composite particles is preferably 20% by mass or more and 95% by mass or less. As a result, the external additive is easily melted instantly by the heat received from the fuser, and the low temperature fixability of the toner can be further improved.

The composite particles have a coating layer of an organosilicon polymer on the surface of the core containing an organic substance. The coating is a state in which the organosilicon polymer is covered with a layer of the organosilicon polymer inside, and may be completely covered or partially exposed.
A known method can be used to form a coating layer of the organosilicon polymer in the composite particles.

For example, it is a method using a silane coupling agent. The core containing the parent organic substance is dispersed in the organic solvent. After dropping the solution into the aqueous phase, the solvent is removed to prepare a dispersion solution of core fine particles. Then, after adjusting the pH of the dispersion solution, a silane coupling agent is added. According to this method, the silane coupling agent undergoes hydrolysis and polycondensation in the dispersion solution, and is deposited on the surface of the core fine particles by hydrophobic interaction. In this way, a coating layer of the organosilicon polymer can be formed on the surface of the core fine particles.
It is also possible to use a polymerizable silane coupling agent. When a polymerizable silane coupling agent having a vinyl group or the like is deposited on the surface of the core fine particles, a radical initiator such as potassium persulfate is added to promote vinyl polymerization on the surface of the core fine particles. This makes it possible to form a coating layer of a stronger organosilicon polymer. By forming a strong coating layer, it is effective in improving the durability of the toner.
As the silane coupling agent, the following are preferably used.
Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyl Methyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, methacryloxypropyltrimethoxysilane.

The surface of the composite particle may be treated with an organosilicon compound or a silicone oil. By treating with an organosilicon compound or silico oil, the hydrophobicity can be enhanced, so that the toner has stable developability even in a high temperature and high humidity environment. Examples of organosilicon compounds include the following.

Hexamethyldisilazane, methyltrimethoxysilane, octyltrimethoxysilane, isobutyltrimethoxysilane, trimethylsilane, trimethylchlorsilane, trimethylethoxysilane, dimethyldichlorosilane, methyltricrolsilane, allyldimethylchlorsilane, allylphenyldichlorosilane , Benzyldimethylchlorsilane, brommethyldimethylchlorsilane, α-chlorethyltrichlorosilane, β-chlorethyltrichlorsilane, chlormethyldimethylchlorsilane, triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, Didimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, 1-hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2-12 siloxane units per molecule Dimethylpolysiloxane or the like containing one hydroxyl group in Si, which is a unit located at the terminal. These are used in one or a mixture of two or more.

The silicone oil preferably has a viscosity at 25 ° C. of 30 mm ² / s or more and 1000 mm ² / s or less. Specific examples of such silicone oil include dimethyl silicone oil, methyl phenyl silicone oil, α-methyl styrene modified silicone oil, chlorphenyl silicone oil, fluorine-modified silicone oil and the like.
Examples of the method for treating silicone oil include the following methods. A method of directly mixing composite particles treated with a silane coupling agent and silicone oil using a mixer such as a Henschel mixer. A method of spraying silicone oil on composite particles. Alternatively, a method in which the silicone oil is dissolved or dispersed in an appropriate solvent, and then composite particles are added and mixed to remove the solvent is more preferable.

The composite particles preferably have a number average particle size Dn measured by a dynamic light scattering method of 30 nm or more and 500 nm or less. Within the above range, the paper and toner are likely to adhere to each other during transfer and fixing, and an effect on transferability and fixability can be easily obtained. In addition, durability is likely to be improved due to its role as a spacer. More preferably, the number average particle diameter Dn is 50 nm or more and 300 nm or less.
Further, the ratio Dv / Dn of the volume average particle size Dv of the composite particles to the Dn is preferably 2.0 or less, and more preferably 1.8 or less. The lower limit is not particularly limited, but is preferably 1.5 or more. This Dv / Dn is an index indicating the uniformity of the particle size, and when it is 2.0 or less, the particle size distribution is sharp and the uneven melting between the particles is suppressed, and the uneven fixing is improved, which is preferable.

The content of the composite particles in the toner is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner particles. When it is 0.2 parts by mass or more, the melting effect near the toner surface is improved, and when it is 10 parts by mass or less, the elasticity of the base body can be maintained at the time of fixing, so that fixing unevenness is less likely to occur.

The toner according to the present invention may contain an external additive other than the composite particles. In particular, in order to improve the fluidity and chargeability of the toner, it is preferable to add a fluidity improver as another external additive. The following can be used as the fluidity improver.
For example, fluororesin powders such as vinylidene fluoride fine powder, polytetrafuloloethylene fine powder; fine powder silica such as wet formula silica, dry formula silica, fine powder titanium oxide, or fine powder alumina, or them. Surface-treated with silane compounds, titanium coupling agents, silicone oil; oxides such as zinc oxide and tin oxide; strontium titanate, barium titanate, calcium titanate, strontium zirconate and calcium zirconate. Compound oxides such as calcium carbonate and carbonate compounds such as magnesium carbonate.
A preferable fluidity improver is a fine powder produced by vapor phase oxidation of a silicon halogen compound, which is so-called dry silica or fumed silica. For example, it utilizes the pyrolysis oxidation reaction of silicon tetrachloride gas in oxyhydrogen flame, and the basic reaction formula is as follows.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

In this manufacturing process, it is also possible to obtain a composite fine powder of silica and other metal oxides by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound, and these are also included as silica. do. It is preferable that the average primary particle size in the particle size distribution based on the number is 5 nm or more and 30 nm or less because high chargeability and fluidity can be obtained.
As the fluidity improving agent, treated silica fine powder obtained by hydrophobizing the silica fine powder generated by the vapor phase oxidation of the silicon halogen compound is more preferable. For the hydrophobization treatment, the same method as the surface treatment of the composite particles can be used. The fluidity improver preferably has a specific surface area of 30 m ² / g or more and 300 m ² / g or less due to nitrogen adsorption measured by the BET method. Further, it is preferable to use a total amount of 0.01 parts by mass or more and 3 parts by mass or less of the fluidity improver with respect to 100 parts by mass of the toner particles.

The toner can be used as a one-component developer by mixing with a fluidity improver and, if necessary, with another external additive (for example, a charge control agent). It can also be used as a two-component developer in combination with a carrier. Conventionally known carriers can be used as the carrier when used in the two-component developing method.
Specifically, metals such as surface-oxidized or unoxidized iron, nickel, cobalt, manganese, chromium, and rare earths, and alloys or oxides thereof are preferably used. Further, those in which a substance of a styrene resin, an acrylic resin, a silicone resin, a fluororesin, or a polyester resin is adhered or coated on the surface of the carrier particles are preferably used.

Next, the toner particles will be described.
First, the binder resin used for the toner particles will be specifically described.
Examples of the binder resin include polyester resin, vinyl resin, epoxy resin, and polyurethane resin. In particular, from the viewpoint of uniformly dispersing the charge control agent having polarity, it is generally preferable to contain a polyester resin having high polarity in terms of developability.
Further, in the present invention, the toner has composite particles having excellent melting characteristics because of the role of imparting meltability in the vicinity of the toner surface. Therefore, it is preferable that the softening point Tm of the toner particles is higher than the softening point Tm of the composite particles.
The softening point (Tm) of the toner particles is set to 90 ° C. or higher and 180 ° C. or lower in order to maximize the effect of the melting property near the toner surface. More preferably, it is 110 ° C. or higher and 170 ° C. or lower, and is excellent in the effect of melting characteristics near the toner surface and the durability of the toner.
Further, the binder resin preferably has a glass transition point (Tg) of 45 ° C. or higher and 70 ° C. or lower from the viewpoint of storage stability.

The toner particles may further contain magnetic iron oxide particles and be used as a magnetic toner. In this case, the magnetic iron oxide particles can also serve as a colorant. The magnetic iron oxide particles contained in the magnetic toner include iron oxide particles such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or these metals and aluminum, cobalt, and the like.
Examples include alloys of metals such as copper, lead, magnesium, tin, zinc, antimony, bismuth, calcium, manganese, titanium, tungsten and vanadium or mixtures thereof.
The number average particle diameter of these magnetic iron oxide particles is preferably 2 μm or less. More preferably, it is 0.05 μm or more and 0.5 μm or less. The content in the toner is preferably 20 parts by mass or more and 200 parts by mass or less, and more preferably 40 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the binder resin.

Examples of the colorant used in the present invention are given below.
As the black colorant, for example, carbon black, grafted carbon, or a black colorant using the yellow / magenta / cyan colorant shown below can be used. Examples of the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds and the like. Examples of the cyan colorant include a copper phthalocyanine compound and its derivative, an anthraquinone compound, and a basic dye lake compound.
These colorants can be used alone or in the form of a solid solution. The colorant is selected in terms of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in toner. The content of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

The toner may contain wax in order to impart releasability at the time of fixing.
Examples of the wax include a polyolefin copolymer, a polyolefin wax, a microcrystalline wax, a paraffin wax, an aliphatic hydrocarbon wax such as Fisher Tropsch wax, and an ester wax.
The wax content is preferably 0.2 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the binder resin.

A charge control agent can be used for the toner in order to stabilize its triboelectricity. As the charge control agent, one that controls the toner to be negatively charged and one that controls the toner to be positively charged are known, and one or two or more kinds of various ones are used depending on the type and application of the toner. Can be done.
Examples of the one that controls the toner to be negatively charged include the following. Organic metal complex (monoazo metal complex; acetylacetone metal complex); a metal complex or metal salt of an aromatic hydroxycarboxylic acid or an aromatic dicarboxylic acid. Other examples include aromatic products and polycarboxylic acids and their metal salts and anhydrides; phenol derivatives such as esters and bisphenols. Examples of the one that controls the toner to be positively charged include the following. Modifications with niglosin and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammoniumtetrafluoroborate, and analogs thereof; onium salts such as phosphonium salt. And these lake pigments; triphenylmethane dyes and their lake pigments (as lake agents, phosphotung acid, phosphomolybdic acid, phosphotungene molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic acid. Compounds, etc.); Metal salts of higher fatty acids.

The method for producing the toner particles is not particularly limited, and for example, a so-called polymerization method such as a pulverization method, an emulsion polymerization method, a suspension polymerization method and a dissolution suspension method can be used.
In the pulverization method, first, the binder resin constituting the toner particles, the colorant, and if necessary, additives such as wax and charge control agent are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill. Next, the obtained mixture is melt-kneaded using a heat kneader such as a twin-screw kneading extruder, a heating roll, a kneader, and an extruder, cooled and solidified, and then pulverized and classified to obtain toner particles.
Further, if necessary, the desired external additive can be mixed with a mixer such as Henschel mixer to obtain a toner.

Next, a method for measuring each physical property according to the present invention will be described.
<Measurement method of powder dynamic viscoelasticity>
Approximately 50 mg of toner is precisely weighed and charged into the attached material pocket (length x width x thickness: 17.5 mm x 7.5 mm x 1.5 mm) so that the toner is in the center. Measurement is performed using DMA8000) manufactured by Elmer. Use the measurement wizard to measure under the following measurement conditions.
Frequency: Single frequency 1Hz
Amplitude: 0.05mm
Temperature rise speed: 2 ° C / min
Starting temperature: 30 ° C
End temperature: 180 ° C
Data acquisition interval: 0.3 second interval In the temperature T [° C] -toner storage elastic modulus E'[Pa] curve obtained by powder dynamic viscoelasticity measurement, the temperature of E'is 1.5 seconds before and after each temperature. The amount of change with respect to T (dE'/ dT) is measured. The change amount (dE'/ dT) is calculated in the temperature range of 30 ° C. to 180 ° C. by the above method, and the curve of the change amount (dE' / dT) of the toner storage elastic modulus E'with respect to the temperature T (temperature T [° C.]]. -Change amount dE'/ dT [Pa / ° C] curve) is obtained. In the temperature T [° C.]-change amount dE'/ dT [Pa / ° C.] curve, a minimum value of -1.00 × ¹⁰⁸ or less was specified between the onset temperature and 90 ° C., and the minimum value was specified. Of these, the minimum value of the amount of change (dE'/ dT) that first appears when viewed from the low temperature side is calculated.
Further, the onset temperature in the temperature T [° C.]-change amount dE'/ dT [Pa / ° C.] curve is a straight line extending the baseline on the low temperature side of the E'curve to the high temperature side and E'. It is the temperature indicating the intersection with the tangent line drawn at the point where the slope of the curve becomes maximum.

<Measurement method of dynamic viscoelasticity>
As a measuring device, a rotary flat plate type rheometer "ARES" (manufactured by TA INSTRUMENTS) is used.
As a measurement sample, in an environment of 25 ° C., 0.2 g of toner was pressure-molded into a disk shape with a diameter of 7.9 mm and a thickness of 2.0 ± 0.3 mm using a tablet molder (10 MPa, 10 MPa, Use the sample after 60 seconds).
The sample is mounted on a parallel plate, the temperature is raised from room temperature (25 ° C.) to 100 ° C. in 15 minutes, the shape of the sample is adjusted, and then the sample is cooled to the viscoelasticity measurement start temperature to start the measurement. At this time, it is important to set the sample so that the initial normal force becomes 0. Further, as described below, in the subsequent measurement, the influence of the normal force can be canceled by setting the automatic tension adjustment (Auto Tension Adjustment ON). From this measurement, a temperature T [° C.]-Toner storage elastic modulus G'[Pa] curve can be obtained.
The measurement is performed under the following conditions.
(1) A parallel plate with a diameter of 7.9 mm is used.
(2) The frequency is 6.28 rad / sec (1.0 Hz).
(3) The applied strain initial value (Strine) is set to 0.1%.
(4) Measurement is performed at a rate of temperature rise (Ramp Rate) of 2.0 ° C./min between 30 ° C. and 200 ° C. The measurement is performed under the following automatic adjustment mode setting conditions. The measurement is performed in the automatic strain adjustment mode (Auto Stream).
(5) Set the maximum strain (Max Applied Straight) to 20.0%.
(6) The maximum torque (Max Allowed Torque) is set to 200.0 g · cm, and the minimum torque (Min Allowed Torque) is set to 0.2 g · cm.
(7) Strain adjustment is set to 20.0% of Current Strain. In the measurement, an automatic tension adjustment mode (Auto Tension) is adopted.
(8) Automatic tension direction is set as compression.
(9) The initial static force is set to 10.0 g, and the automatic tension sensitivity is set to 40.0 g.
(10) The operating condition of the automatic tension is that the sample modulus is 1.0 × 10 ³ Pa or more.

<Measurement method of acid value>
The acid value is the number of mg of potassium hydroxide required to neutralize the acid contained in 1 g of the sample. The acid value is measured according to JIS K 0070-1992, but specifically, it is measured according to the following procedure.
(1) Preparation of Reagents 1.0 g of phenolphthalein is dissolved in 90 mL of ethyl alcohol (95% by volume), and ion-exchanged water is added to make 100 mL to obtain a phenolphthalein solution.
Dissolve 7 g of special grade potassium hydroxide in 5 mL of water and add ethyl alcohol (95% by volume) to make 1 L.
Put it in an alkali-resistant container so as not to touch carbon dioxide gas, leave it for 3 days, and then filter it to obtain a potassium hydroxide solution. The resulting potassium hydroxide solution is stored in an alkali resistant container. The factor of the potassium hydroxide solution is determined from the amount of the potassium hydroxide solution required for neutralization by taking 25 mL of 0.1 M hydrochloric acid in a triangular flask, adding a few drops of the phenolphthaline solution, and titrating with the potassium hydroxide solution. As 0.1M hydrochloric acid, one prepared according to JIS K 8001-1998 is used.
(2) Operation (A) 2.0 g of this test sample is precisely weighed in a 200 mL Erlenmeyer flask, 100 mL of a mixed solution of toluene / ethanol (2: 1) is added, and the mixture is dissolved over 5 hours. Then, a few drops of phenolphthalein solution are added as an indicator, and titration is performed using a potassium hydroxide solution. The end point of the titration is when the light red color of the indicator continues for about 30 seconds.
(B) Blank test Titration is performed in the same manner as above except that no sample is used (that is, only a mixed solution of toluene / ethanol (2: 1) is used).
(3) Calculation of acid value
AV = [(B-AB) x f x 5.61] / S
Here, AV: acid value (mgKOH / g), A: addition amount of potassium hydroxide solution in blank test (mL), B: addition amount of potassium hydroxide solution in this test (mL), f: potassium hydroxide Solution factor, S: sample (g).

<Measurement of weight average molecular weight Mw and number average molecular weight Mn by GPC>
The column is stabilized in a heat chamber at 40 ° C., THF is flowed through the column at this temperature as a solvent at a flow rate of 1 ml per minute, and about 100 μl of a THF sample solution is injected for measurement.
In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value and the count value of the calibration curve prepared from several types of monodisperse polystyrene standard samples.
As the standard polystyrene sample for preparing a calibration curve, for example, a sample having a molecular weight of about 102 to ¹⁰⁷ manufactured by Tosoh Corporation or Showa Denko Corporation is used, and it is appropriate to use a standard polystyrene sample having about ¹⁰ points.
Further, the detector uses an RI (refractive index) detector. As a column, it is preferable to combine a plurality of commercially available polystyrene gel columns, for example, a combination of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko Corporation, or manufactured by Tosoh Corporation. TSKgel G1000H (H _XL ), G2000H (H _XL ), G3000H (H _XL ), G4000H (H _XL ), G5000H (H _XL ), G6000H (H _XL ), G7000H (H _XL ), TSKgund be able to.
The sample is prepared as follows.
The sample is placed in THF and left to stand for 5 hours, and then shaken sufficiently to dissolve the sample in THF until the union of the sample disappears. The dissolution temperature is basically 25 ° C., and the solution is dissolved in the range of 25 to 50 ° C. depending on the solubility of the sample. After that, it is stored at 25 ° C. for 12 hours or more.
At this time, the leaving time in THF is set to 24 hours. After that, a sample that has passed through a sample processing filter (a pore size of 0.2 μm or more and 0.5 μm or less, for example, Mysholidisk H-25-2 (manufactured by Tosoh Corporation) can be used) is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 mg / ml or more and 5.0 mg / ml or less.

<Method of confirming urethane bond of crystalline polyester resin>
The presence or absence of urethane bond is confirmed by the FT-IR spectrum by the ATR method. The FT-IR spectrum by the ATR method is performed by using a Frontier (Fourier transform infrared spectrophotometer, manufactured by PerkinElmer) equipped with a Universal ATR Sampleing Accessory (universal ATR measurement accessory).
As the ATR crystal, Ge's ATR crystal (refractive index = 4.0) is used.
Other conditions are as follows.
Range
Start: 4000cm ^-1
End: 600 cm ^-1 (Ge ATR crystal)
Scan number: 8
Resolution: 4.00 cm ^-1
Advanced: With CO ₂ / H ₂ O correction If the peak top is in the range of 1570 to 1510 cm ^-1 , it is judged to have a urethane bond.

<Measurement of softening point (Tm) of toner particles and organic matter (crystalline polyester resin)>
The softening points of toner particles and organic substances are measured using a constant load extrusion type thin tube rheometer "Flow Tester CFT-500D" (manufactured by Shimadzu Corporation) according to the manual attached to the device. In this device, while applying a constant load from the top of the measurement sample with a piston, the temperature of the measurement sample filled in the cylinder is raised and melted, and the melted measurement sample is pushed out from the die at the bottom of the cylinder. A flow curve showing the relationship between and temperature can be obtained.
The softening point is the "melting temperature in the 1/2 method" described in the manual attached to the "flow characteristic evaluation device flow tester CFT-500D". The melting temperature in the 1/2 method is calculated as follows. First, 1/2 of the difference between the piston descent amount Smax at the time when the outflow ends and the piston descent amount Smin at the time when the outflow starts is obtained (this is defined as X. X = (Smax-Smin) /. 2). The temperature of the flow curve when the amount of descent of the piston is the sum of X and Smin in the flow curve is the melting temperature in the 1/2 method. As the measurement sample, about 1.0 g of the sample was compression-molded in an environment of 25 ° C. using a tablet molding compressor (for example, NT-100H, manufactured by NPA System Co., Ltd.) at about 10 MPa for about 60 seconds. Use a columnar one with a diameter of about 8 mm.
The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rise method Temperature rise rate: 4 ° C / min
Starting temperature: 40 ° C
Reaching temperature: 200 ° C
Measurement interval: 1.0 ° C
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0 mm

<Measurement of glass transition temperature Tg>
The glass transition temperature Tg is measured according to ASTM D3418-82 using a differential scanning calorimeter analyzer "Q2000" (manufactured by TA Instruments). The melting point of indium and zinc is used for temperature correction of the device detector, and the heat of fusion of indium is used for the correction of calorific value. Specifically, about 2 mg of a sample is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference, and the temperature rise rate is in the measurement temperature range of -10 to 200 ° C. The measurement is performed at 10 ° C./min. In the measurement, the temperature is once raised to 200 ° C., then lowered to −10 ° C. at 10 ° C./min, and then raised again at 10 ° C./min. The specific heat change can be obtained in the temperature range of 30 ° C. to 100 ° C. in the second temperature raising process. The intersection of the line at the midpoint of the baseline before and after the specific heat change at this time and the differential thermal curve is defined as the glass transition temperature Tg.

<Measuring method of number average particle size and volume average particle size of primary particles of composite particles (external additive)>
The number average particle size Dn and the volume average particle size Dv of the composite particles are measured as follows.
The number average particle size is measured using a zetasizer Nano-ZS (manufactured by MALVERN).
The device can measure the particle size by a dynamic light scattering method. First, the sample to be measured is diluted and adjusted so that the solid-liquid ratio is 0.10% by mass (± 0.02% by mass), collected in a quartz cell, and placed in a measuring unit. As the measurement conditions, the refractive index of the sample, the refractive index of the dispersion solvent, the viscosity and the temperature are input and measured with the control software Zetasizersoftware 6.30. Dn is used as the number average particle size and Dv is used as the volume average particle size.
Since the composite particles are a composite of inorganic fine particles and resin fine particles, the refractive index is calculated by taking a weight average from the refractive index of the inorganic fine particles and the refractive index of the resin used for the resin fine particles. The refractive index of the inorganic fine particles is adopted from the Chemical Handbook. As the refractive index of the resin fine particles, the refractive index of the resin used for the resin fine particles is adopted as the refractive index built into the control software. However, if there is no built-in refractive index, the value described in the National Institute for Materials Science Polymer Database is used.
For the refractive index, viscosity and temperature of the dispersion solvent, select the numerical values built in the control software. In the case of a mixed solvent, the weight average of the dispersion media to be mixed is taken.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, the parts used in the examples are based on mass.

<Production example of crystalline resin 1>
・ (Acid component) Decandycarboxylic acid ・ ・ ・ 159 parts ・ (Alcohol component) 1,6-hexanediol ・ ・ ・ 90 parts The above raw materials are charged in a reaction vessel equipped with a stirrer, a thermometer and a nitrogen introduction tube. is. Subsequently, 0.1% by mass of tetraisobutyl titanate was added to the total amount of the above raw materials, and the mixture was reacted at 180 ° C. for 4 hours, then heated to 210 ° C. at 10 ° C./1 hour and kept at 210 ° C. for 8 hours. After that, the reaction was carried out at 8.3 kPa for 1 hour to obtain a crystalline polyester resin 1. The softening point of the crystalline polyester resin 1 was 62 ° C., the weight average molecular weight Mw was 21000, and the acid value was 19 mgKOH / g.
Subsequently, the crystalline polyester resin 1 was charged in a reaction vessel equipped with a stirrer, a thermometer, and a nitrogen introduction tube. 14 parts of hexamethylene diisocyanate (HDI) was added as an isocyanate component to 100 parts of the acid component and the alcohol component, and tetrahydrofuran (THF) was added so that the concentrations of the crystalline polyester resin 1 and HDI were 50% by mass. .. The urethanization reaction was carried out over 10 hours by heating to 50 ° C. The solvent THF was distilled off to obtain a crystalline resin 1. It was confirmed that the crystalline resin 1 had a peak top at 1528 cm ^-1 by FT-IR measurement and had a urethane bond. Further, the crystalline resin 1 had a clear endothermic peak in the measurement by the differential scanning calorimeter (DSC). Table 1 shows the softening point and the weight average molecular weight Mw. The FT-IR spectrum of the crystalline resin 1 is shown in FIG.

<Production examples of crystalline resins 2 to 6>
From the production example of the crystalline resin 1, the monomer formulation, the presence or absence of urethane bond, and the isocyanate component were changed as shown in Table 1, and the reaction conditions were adjusted to obtain crystalline resins 2 to 6. Regarding the amount of the monomer added, the same number of copies as in the production example of the crystalline resin 1 was used. Table 1 shows the physical characteristics of the crystalline resins 2 to 6. The crystalline resins 2 to 6 had a clear endothermic peak in the measurement by the differential scanning calorimeter (DSC).

<Production example of amorphous resin 1>
・ Bisphenol A propylene oxide (2.2 mol) adduct 60.0 mol part ・ Bisphenol A ethylene oxide (2.2 mol) adduct 40.0 mol part ・ Terephthalic acid 77.0 mol part ・ Anhydrous trimellitic acid 3.0 mol part The above polyester The monomer mixture was charged into a 5 liter autoclave, and 0.05% by mass of tetraisobutyl titanate was added to the total amount of the polyester monomer mixture. A reflux condenser, a water separation device, a nitrogen gas introduction tube, a thermometer and a stirrer were attached, and a polycondensation reaction was carried out at 230 ° C. while introducing nitrogen gas into the autoclave. The reaction time was adjusted to the desired softening point. After completion of the reaction, the resin was taken out from the container, cooled and pulverized to obtain an amorphous resin 1. Table 2 shows various physical characteristics of the obtained amorphous resin 1.

<Production example of amorphous resin 2>
・ Bisphenol A propylene oxide (2.2 mol) adduct 60.0 mol part ・ Bisphenol A ethylene oxide (2.2 mol) adduct 40.0 mol part ・ Terephthalic acid 77.0 mol part The above polyester monomer mixture was charged into a 5 liter autoclave. 0.05% by mass of tetraisobutyl titanate was added to the total amount of the polyester monomer mixture. A reflux condenser, a water separation device, a nitrogen gas introduction tube, a thermometer and a stirrer were attached, and a polycondensation reaction was carried out at 230 ° C. while introducing nitrogen gas into the autoclave. The reaction time was adjusted to the desired softening point. After completion of the reaction, the resin was taken out from the container, cooled and pulverized to obtain an amorphous resin 2. Table 2 shows various physical characteristics of the obtained amorphous resin 2.

<Production example of composite particle 1>
[Preparation of organic fine particles]
-Preparation of aqueous phase Put 50 parts of ion-exchanged water in a No. 11 mayonnaise bottle and dissolve 0.2 part of sodium lauryl sulfate.
-Preparation of oil phase Dissolve 3 parts of crystalline resin 1 in 7 parts of toluene.
The oil phase is added to the stirred aqueous phase, and the mixture is dispersed with an ultrasonic homogenizer for 5 minutes (intermittent irradiation 1s, stop 1s). Then, after desolvating toluene with an evaporator, an excess amount of sodium lauryl sulfate was removed with an ultrafiltration filter to obtain core fine particles 1 containing an organic substance.
[Formation of coating layer]
The pH of the core fine particles 1 is measured, and 10% by mass hydrochloric acid is added to adjust the pH to about 2. MPTMS (methacryloxypropyltrimethoxysilane) is added to the core fine particle 1 dispersion liquid so as to have a mass ratio of 3/2 with respect to the core fine particle 1, and the mixture is heated at 65 ° C. for 30 minutes.
Then, a 10% by mass aqueous solution of KPS (potassium persulfate) is added so that MPTMS / KPS becomes 10/1, and the mixture is heated at 80 ° C. for 3 hours. Then, it cooled and dried to obtain composite particles 1. Table 3 shows the formulation of the composite particle 1 and its physical properties. From the observation with a transmission electron microscope, it was confirmed that the composite particle 1 had a core-shell structure in which a coating layer of an organic silicon polymer was formed on the surface of the organic fine particles.

<Production example of composite particles 2 to 11>
In the production example of the composite particle 1, the composite particles 2 to 11 were obtained in the same manner except that the organic composition and the amount of the core were changed. The prescription and its physical characteristics are shown in Table 3. From the observation with a transmission electron microscope, it was confirmed that the composite particles 2 to 11 had a core-shell structure in which a coating layer of an organic silicon polymer was formed on the surface of the organic fine particles.
The confirmation of the covering layer was carried out as follows.
After the composite particles are dispersed in the room temperature curable epoxy resin, the epoxy resin is cured by leaving it in an atmosphere of 40 ° C. for 2 days. A flaky sample is cut out from the obtained cured product using a microtome equipped with a diamond blade. This sample is magnified with a transmission electron microscope (trade name: Tecnai TF20XT, manufactured by FEI) (TEM) at a magnification of 10,000 to 100,000 times, and the cross section of the composite particle is observed.
In the present invention, it is possible to distinguish between the organic silicon polymer portion and the organic matter portion by utilizing the fact that the contrast becomes brighter when the atomic weight is large from the difference in the atomic weights of the atoms in the organic substance and the organic silicon polymer used. .. Furthermore, ruthenium tetroxide staining and osmium tetroxide staining are used to add contrast between the materials. Using a vacuum electron dyeing device (trade name: VSC4R1H, manufactured by Filgen), the flaky sample is placed in a chamber and dyed at a concentration of 5 and a dyeing time of 15 minutes.
As described above, a transmission electron microscope (trade name: Tecnai TF20XT, manufactured by FEI) is used to acquire a bright field image of composite particles at an acceleration voltage of 200 kV. Next, using an EELS detector (trade name: GIF Tridim, manufactured by Gatan), an EF mapping image of the Si—K end (99eV) was obtained by the Three Windows method, and it was confirmed that the organosilicon polymer was present on the surface layer. Confirm.

<Production example of composite particles 12>
Two parts of wax (manufactured by Sazole: C105) were added to Industry Co., Ltd. Cryogenic Sample Crusher (Model JFC-300) manufactured by ltd was used for cryogenic pulverization using liquid nitrogen. Fused silica (BET: 200 m ² / g) is externally mixed using an FM mixer (manufactured by Nippon Coke Industries Co., Ltd.) in an amount of 0.5 part with respect to 50 parts of a frozen pulverized product of wax. It was attached to the surface of the wax. The composite particles 12 were obtained by sieving with a mesh having a mesh size of 30 μm. From the observation with a scanning electron microscope, it was confirmed that the composite particles 12 had fumed silica attached to the surface of the wax without being embedded.
Table 3 shows the formulation of the composite particle 12 and its physical properties.
<Production example of composite particles 13>
In a reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube, 5 parts of crystalline resin 1 and 10 parts of MEK (methyl ethyl ketone) were charged and heated to 50 ° C. to dissolve them.
Then, with stirring, 0.45 parts of triethylamine having a pKa of 10.8 was added as a neutralizing agent. After confirming that the resin is sufficiently dissolved, 75 parts of water is added dropwise at a rate of 2.5 g / min for phase inversion emulsification, whereby the crystalline resin fine particle dispersion liquid 1 (solid content concentration 5. 7% by mass) was obtained.
MEK was sufficiently distilled off by an evaporator at 60 ° C. Here, the pH of the crystalline resin fine particle dispersion liquid 1 was 9.0. The pH was measured while adding 0.1 N hydrochloric acid to the crystalline resin fine particle dispersion liquid 1, and the pH was adjusted to 2.0.
15 parts of MPTMS (methacryloxypropyltrimethoxysilane) was added to 1:10 parts of the crystalline resin fine particle dispersion liquid, and the mixture was heated at 65 ° C. for 30 minutes. Then, 1.5 parts of a 10% by mass aqueous solution of per-KPS (potassium sulfate) was added, and the mixture was heated at 80 ° C. for 3 hours to promote hydrolysis and polycondensation to prepare a coating layer of a silicon polymer. Then, it cooled and dried to obtain composite particles 13.
Table 3 shows the physical characteristics of the composite particle 13. From the observation with a transmission electron microscope, it was confirmed that the composite particle 13 had a core-shell structure in which a coating layer of an organic silicon polymer was formed on the surface of the organic fine particles.
<Production example of composite particles 14>
Dimethylaminoethanol having a pKa of 9.2 was used as a neutralizing agent, and the composite particles 14 were obtained in the same manner as the composite particles 13 except that the pH was adjusted to 3.0 with hydrochloric acid.
Table 3 shows the physical characteristics of the composite particle 14. From the observation with a transmission electron microscope, it was confirmed that the composite particles 14 had a core-shell structure in which a coating layer of an organic silicon polymer was formed on the surface of the organic fine particles.
<Production example of composite particles 15>
The same method as for composite particles 13 except that butylamine having a pKa of 12.5 was used as a neutralizing agent, 0.04 part of sodium lauryl sulfate was added as a surfactant, and the pH was adjusted to 5.5 with hydrochloric acid. Obtained composite particles 15.
Table 3 shows the physical characteristics of the composite particle 15. From the observation with a transmission electron microscope, it was confirmed that the composite particle 15 had a core-shell structure in which a coating layer of an organic silicon polymer was formed on the surface of the organic fine particles.

<Production example of magnetic iron oxide particles>
1.1 equivalents of caustic soda solution was mixed with ferrous sulfate aqueous solution to prepare an aqueous solution containing ferrous hydroxide. The pH of the aqueous solution was set to 8.0, and an oxidation reaction was carried out at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.
Next, a ferrous sulfate aqueous solution was added to this slurry liquid so as to have an amount of 1.0 equivalent with respect to the initial alkali amount (sodium component of caustic soda), and then the slurry liquid was maintained at pH 12.8 and air was blown into the slurry liquid. While proceeding with the oxidation reaction, a slurry liquid containing magnetic iron oxide was obtained. This slurry is filtered, washed, dried and crushed to have an average number of primary particles of 0.20 μm, a magnetic field of 79.6 kA / m (1000 oersted), a magnetization strength of 65.9 Am ² / kg, and a residue. Magnetic iron oxide particles having an octahedral structure with a magnetization of 7.3 Am ² / kg were obtained.

<Manufacturing example of toner particles 1>
-Amorphous polyester resin A
(50.0 mol part of bisphenol A propylene oxide (2.2 mol) adduct, 50.0 mol part of bisphenol A ethylene oxide (2.2 mol) adduct, 76.0 mol part of terephthalic acid, 4.0 mol part of anhydrous trimellitic acid)
(Tg: 62 ° C, softening point Tm: 135 ° C) 100 parts, magnetic iron oxide particles 75 parts, C105 (manufactured by Sazole) 2 parts, T77 (manufactured by Hodogaya Chemical Co., Ltd.) 2 parts FM mixer (Japan) After pre-mixing with Coke Industries Co., Ltd.), use a twin-screw extruder (trade name: PCM-30, manufactured by Ikekai Iron Works Co., Ltd.) to adjust the temperature so that the melt temperature at the discharge port becomes 150 ° C. It was set and melt-kneaded.
The obtained kneaded product was cooled, roughly pulverized with a hammer mill, and then finely pulverized using a crusher (trade name: Turbo Mill T250, manufactured by Turbo Industries, Ltd.). The obtained finely pulverized powder was classified using a multi-division classifier utilizing the Coanda effect to obtain toner particles 1 having a weight average particle size (D4) of 7.2 μm. The glass transition temperature Tg of the toner particles 1 was 62 ° C., and the softening point Tm was 135 ° C.

<Manufacturing example of toner particles 2>
-Amorphous polyester resin A (Tg: 62 ° C, softening point Tm: 135 ° C) 100 parts-Magnetic iron oxide particles 75 parts-C105 (manufactured by Sazole) 2 parts-T77 (manufactured by Hodoya Chemical Industry Co., Ltd.) 2 parts -The formulation was changed as described above from the production example of the crystalline resin 14 part 4 toner particles 1 to obtain the toner particles 2. The glass transition temperature Tg of the toner particles 2 was 58 ° C., and the softening point Tm was 120 ° C.

<Manufacturing example of toner 1>
・ Toner particles 1 100 parts ・ Composite particles 1 1 part ・ Hydrophobic silica fine powder 1 part (silica surface-treated with dimethyl silicone oil, number of primary particles Average particle diameter: 10 nm, BET specific surface area of raw silica 200 m ² / g)
The above materials were externally mixed with an FM mixer (manufactured by Nippon Coke Industries, Ltd.) to obtain toner 1. Table 5 shows various physical properties of the obtained toner 1.

<Manufacturing examples of toners 2 to 16 and comparative toners 1 to 5>
Toners 2 to 16 and comparative toners 1 to 5 were obtained in the same manner as in the production example of toner 1 except that the type of the externally added material was changed as shown in Table 4. Table 5 shows various physical characteristics.
As the crystalline resins 5 and 6 as the external additives, the crystalline resins 5 and 6 shown in Table 1 were freeze-milled and used. The number average particle diameter of the crystalline resins 5 and 6 was 100 nm.

<Example 1>
The machine used for evaluation in this embodiment is a main body modified so that the process speed of a commercially available magnetic one-component printer HP LaserJet Enterprise M606dn (manufactured by Hewlett-Packard Company: process speed 350 mm / s) is 400 mm / s. The following evaluation was carried out using toner 1. In addition, Vitality (manufactured by Xerox, basis weight 75 g / cm ² , letter) was used as the evaluation paper. The evaluation results are shown in Table 6.

<Examples 2 to 16>
The evaluation was performed in the same manner as in Example 1 except that toners 2 to 16 were used. The evaluation results are shown in Table 6. Hereinafter, Example 11 will be referred to as Reference Example 11.

<Comparative Examples 1 to 5>
The evaluation was performed in the same manner as in Example 1 except that the comparative toners 1 to 5 were used. The evaluation results are shown in Table 6.

<Evaluation of low temperature fixability>
For the evaluation of low temperature fixability, the fuser of the modified evaluation machine was taken out to the outside, the temperature of the fuser could be set arbitrarily, and the external fuser modified so that the process speed was 400 mm / sec was used. Using this device, the temperature is adjusted every 5 ° C. in the range of 170 ° C. or higher and 220 ° C. or lower, and a halftone image is output so that the image density is 0.60 or higher and 0.65 or lower. The obtained image was rubbed 5 times back and forth with Sylbon paper to which a load of 4.9 kPa was applied, and the density reduction rate of the image density before and after the rubbing was measured.
Plot the set temperature of the fuser on the horizontal axis and the concentration decrease rate on the vertical axis on the coordinate plane, connect all the plots with a straight line, and start fixing the toner with the set temperature of the fuser when the concentration decrease rate is 10%. The temperature was used, and the low temperature fixability was evaluated according to the following criteria. The lower the fixing start temperature, the better the low temperature fixing property. The low temperature fixability was evaluated in a low temperature and low humidity environment (temperature 7.5 ° C., relative humidity 15%), which is a disadvantageous condition for the thermal fixing of the toner.
・ A: Fixing start temperature is less than 190 ℃ ・ B: Fixing start temperature is 190 ℃ or more and less than 200 ℃ ・ C: Fixing start temperature is 200 ℃ or more and less than 210 ℃ ・ D: Fixing start temperature is 210 ℃ or more

<Evaluation of uneven fixing>
For the evaluation of fixing unevenness, the fixing device of the above-mentioned modified evaluation machine was taken out to the outside, the temperature of the fixing device could be set arbitrarily, and the external fixing device modified so that the process speed was 400 mm / sec was used. Using this device, a halftone image is output so that the image density is 0.70 or more and 0.75 or less. The set temperature of the fuser is changed depending on the evaluation toner, and is set to the temperature + 10 ° C. when the image density reduction rate of each toner is 10% in the low temperature fixability evaluation. It is visually determined whether or not there is density unevenness on this halftone image. The evaluation was performed in a normal temperature and humidity environment (temperature 23 ° C., relative humidity 60%).
A: Light and shade unevenness has not occurred.
B: Light and shade unevenness occurs very slightly.
C: Light and shade unevenness occurs, but it is not very noticeable.
D: Light and shade unevenness occurs on the entire surface and is conspicuous.

<Evaluation of paper discharge adhesiveness>
Regarding the evaluation of the paper ejection adhesiveness, the evaluation was carried out using the above-mentioned modified evaluation machine with all the cooling fans in the main body stopped.
Fill the specified process cartridge with toner, and in double-sided printing mode, print a solid image on the front side and a text image (E character, print rate 5%) on the back side for 100 sheets in a row (200 pages) and eject the paper. The image was laminated on the part.
After leaving it for 10 minutes after printing, peel off 100 images one by one and visually check them. The toner is missing due to the adhesion between the solid image (front side) and the text image (back side), and the image is white. The number of sheets (the number of missing sheets) was counted, and the number was used as the evaluation of the paper ejection adhesiveness. The smaller this number is, the better the paper ejection adhesiveness is. The evaluation was performed under high temperature and high humidity (temperature 32.5 ° C., relative humidity 85%) where the paper ejection adhesiveness was severe.
-A: The number of missing sheets is 0.
-B: The number of missing sheets is 1 or more and 5 or less.
-C: The number of missing sheets is 6 or more and 10 or less.
-D: The number of missing sheets is 11 or more.

<Evaluation of durable developability>
Toner was filled into a given process cartridge. In a mode in which the horizontal line pattern with a print rate of 2% is set as 2 sheets / job and the machine is temporarily stopped between jobs and then the next job is started, a total of 12000 sheets are printed out. Carried out. In the 10th and 12000th sheets, a solid image of a 5 mm circle was projected instead of the horizontal line pattern, the image density was measured, and the difference was used as an evaluation of durability developability. The evaluation was performed under high temperature and high humidity (temperature 32.5 ° C., relative humidity 85%), which is severe in developability. The image density was measured by measuring the reflection density of a solid image of a 5 mm circle using a Macbeth densitometer (manufactured by Macbeth), which is a reflection densitometer, using an SPI filter. The smaller the number, the better.
A: (The difference in image density between the 10th and 12000th images is less than 0.15)
B: (The difference in image density between the 10th and 12000th images is 0.15 or more and less than 0.25)
C: (The difference in image density between the 10th and 12000th images is 0.25 or more and less than 0.35)
D: (The difference in image density between the 10th and 12000th images is 0.35 or more and less than 0.45)
E: (The difference in image density between the 10th and 12000th images is 0.45 or more)

Claims (12)

A toner having toner particles having a binder resin and a colorant, and an external additive.
The external preparation is
With a core containing organic matter,
The coating layer of the organosilicon polymer on the surface of the core and
It is a core-shell type composite particle with
The softening point (Tm) of the organic substance is 50 ° C. or higher and 105 ° C. or lower.
The organosilicon polymer is a polymer of a polymerizable silane coupling agent.
The softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
The amount of change (dE') of the toner storage elastic modulus E'with respect to the temperature T based on the temperature T [° C.]-Toner storage elastic modulus E'[Pa] curve obtained by the powder dynamic viscoelasticity measurement of the toner. When the curve of / dT) is obtained,
The change amount (dE'/ dT) curve has a minimum value of −1.00 × ¹⁰⁸ or less between the onset temperature and 90 ° C., and the minimum value on the lowest temperature side is the minimum value. A toner characterized by being 1.35 × ¹⁰⁸ or less. When the temperature at which the minimum value on the lowest temperature side in the curve of the change amount (dE'/ dT) of the toner storage elastic modulus E'with respect to the temperature T is set to T _max ,
The toner according to claim 1, wherein the stored elastic modulus G'(T _max ) [Pa] when the T _max obtained by the dynamic viscoelasticity measurement of the toner is reached is 2.50 × ¹⁰⁸ or more. The toner according to claim 1 or 2, wherein the acid value of the organic substance is 4 mgKOH / g or more and 20 mgKOH / g or less. The toner according to any one of claims 1 to 3, wherein the organic substance contains a crystalline polyester resin. The toner according to claim 4, wherein the crystalline polyester resin has a weight average molecular weight Mw of 18,000 or more. The toner according to claim 4 or 5, wherein the crystalline polyester resin has a urethane bond. The number average particle size Dn measured by the dynamic light scattering method of the composite particles is 50 nm or more and 300 nm or less.
The toner according to any one of claims 1 to 6, wherein the ratio Dv / Dn of the volume average particle size Dv of the composite particles to the Dn is 2.0 or less. A toner having toner particles having a binder resin and a colorant, and an external additive.
The external preparation is
With a core containing crystalline polyester resin,
A coating layer containing an organosilicon polymer on the surface of the core, and
It is a core-shell type composite particle with
The softening point of the toner particles is 90 ° C. or higher and 180 ° C. or lower.
The softening point (Tm) of the crystalline polyester resin is 50 ° C. or higher and 105 ° C. or lower.
A toner characterized in that the organosilicon polymer is a polymer of a polymerizable silane coupling agent . The toner according to claim 8 , wherein the acid value of the crystalline polyester resin is 4 mgKOH / g or more and 20 mgKOH / g or less. The toner according to claim 8 or 9 , wherein the crystalline polyester resin has a urethane bond. The toner according to any one of claims 8 to 10, wherein the crystalline polyester resin has a weight average molecular weight Mw of 18,000 or more. An external additive for toner, which is a core-shell type composite particle having a core containing a crystalline polyester resin and a coating layer containing an organic silicon polymer on the surface of the core.
The softening point (Tm) of the crystalline polyester resin is 50 ° C. or higher and 105 ° C. or lower.
The organosilicon polymer is a polymer of a polymerizable silane coupling agent.
The number average particle size Dn measured by the dynamic light scattering method of the composite particles is 50 nm or more and 300 nm or less.
An external additive for toner, wherein the ratio Dv / Dn of the volume average particle size Dv of the composite particles to the Dn is 2.0 or less.

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