JP2579198B2 - Developer for electrostatic charge development - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for electrostatic charge development used for developing an electric latent image in electrophotography or electrostatic printing.

[Prior art] Electrophotography involves an inorganic photoconductive material such as selenium, zinc oxide and cadmium sulfide, or an organic photoconductive material such as anthracene and polyvinyl carbazole in a binder resin as required. An electrostatic latent image is formed on the attenuated photoconductive layer or the photosensitive plate, developed with a developer made of toner, transferred to paper, a sheet, etc., and then a solvent,
It is fixed by heat, pressure and the like.

In electrophotography, the triboelectric charging property between the toner and the toner carrier during development is important. That is, when the charge amount of the toner is low, the electrostatic attraction between the toner and the toner carrier is weakened, and the toner is easily released from the toner carrier, so that fogging occurs on an image. . On the other hand, if the charge amount is too large, the toner is less likely to be detached from the toner carrier, and not only a strong electric field is required for the apparatus, but also the developability is reduced, and image density becomes thin and density unevenness occurs. Therefore, it is necessary to control the charge amount in a suitable range for producing the toner.

In recent years, demand for color toners has been increasing. However, color toners are generally non-magnetic toners and do not include a magnetic substance.
In addition, from the viewpoint of color saturation, a dielectric substance such as carbon black is often not included. Therefore, there is no portion that leaks the charge, and the charge tends to be excessively large as compared with the normal toner. In particular, this tendency is remarkable in a negatively chargeable color toner using polyester as a binder resin of the toner. The polyester resin is excellent in the fixing property, but has a strong negative charging property, and the phosophobic silica used as a fluidity-imparting agent also promotes excessive charging.

In recent years, there has been a strong demand for higher image quality of copying machine images. On the other hand, the toner is reduced in particle size to achieve high image quality. However, even if the particle size of the toner is reduced, the charge amount is easily movable.

Therefore, for the purpose of preventing excessive charging, addition of a conductive substance, addition of a low-charging substance, addition of a reverse-polarity substance, and the like have been performed, but each has disadvantages.

First, when a conductive substance is added, the minimum charging under high humidity is remarkable, and adverse effects such as uneven image density and fog occur. Further, since the conductive substance is generally colored, it adversely affects the color of the color toner.

Further, addition of a low-charge material (for example, see JP-A-56-9254)
No. 5, JP-A-60-217368), a large amount of addition is required to obtain a sufficient fluidity-imparting effect, and the charge amount is excessively lowered or sufficient fluidity is not obtained. In many cases, the imparting effect cannot be obtained.

In addition, when the opposite polarity substance is added, if coarse particles are contained in the opposite polarity substance, the toner aggregates around the center, and a toner mass of the opposite polarity may be generated. This toner mass is
Since a non-image area is developed and image quality is deteriorated, a step of removing coarse particles or toner lumps is required.

On the other hand, besides the charge amount, there are some adverse effects due to the reduction in the particle size of the toner.

If the toner particle size is small, the surface of the magnetic particles will be covered with a small amount of toner, and if the toner concentration (% by weight) is not reduced, toner scattering will occur. When the toner density is reduced, the image density is further reduced.

Further, when the toner particle diameter is small, the number of contact points between the toners increases, and the fluidity of the toner deteriorates. As a result, problems arise in the stability of toner replenishment and the charging of the replenished toner.

In addition, adverse effects such as easy formation of toner aggregates and easy occurrence of carrier spent occur, and it is necessary to take measures against these.

[Problem to be Solved by the Invention] An object of the present invention is to provide a developer capable of obtaining an image having high image quality and good color reproducibility. It is a further object of the present invention to provide a developer which maintains good development characteristics even under low environmental fluctuations, that is, under constant temperature and low humidity, and has appropriate development characteristics even under high temperature and high humidity.

It is a further object of the present invention to provide a toner and a developer having good fluidity.

[Means for Solving the Problems] As a result of intensive studies, the present inventors have completed the present invention based on the findings described below.

The structure of the present invention is a non-magnetic colorant-containing fine particle, a toner comprising a fluidity-imparting agent, and a developer containing magnetic particles, wherein the colorant-containing fine particle has negative chargeability and has a volume average particle diameter of 4 to 4. 10 μm, and as the fluidity imparting agent,
Alumina and / or titanium oxide whose specific surface area according to the BET method is in the range of 30 to ²⁰⁰ m ² / g, and hydrophobic silica whose specific surface area according to the BET method is 80 m ² / g or more, and A developer for electrostatic charge development, wherein a styrene-acrylic copolymer crosslinked with a derivative containing a triazine ring is used as a coating resin for the magnetic particles.

The particle size of the colorant-containing fine particles used in the present invention is 4 to 10 μm in volume average particle size, and further, coarse powder of 16.0 μm or more has a volume average distribution of 1.0% or less, and fine powder of 5.04 μm or less has 35% or less. % Is preferable.

Since the particle diameter is small, the adhesion of the toner to the minute electrostatic latent image is faithful, and the disturbance of the toner at the end of the electrostatic latent image is small. As a result, an image with high resolution and good color reproducibility can be obtained. In particular, in a halftone region in a digital copying machine, a fine latent image is provided, and the effect of the particle size is large, resulting in a good image.

However, since the toner particle size is too small, the charging tends to be excessive. This was solved without any problem as described below.

In order to suppress the charging, but the addition of alumina or titanium oxide is a low charging substances, which are, for reasons discussed below, in the range of 30 m ² / g (about 40mμ) ~200m ² / g (about 12Emumyu) More preferably 80 m ² / g (about 25
It may be in the range of mμ to 150 m ² / g (about 15 mμ).

For example, alumina having a BET specific surface area greater than 200 m ² / g or titanium oxide has sufficient fluidity,
The disadvantage is that the toner tends to deteriorate. Deterioration is due to the fact that when copying is continued while toner consumption is low,
It appears as a phenomenon that the charge amount greatly changes or the fluidity of the developer deteriorates.

Further, with alumina or titanium oxide having a BET specific surface area of less than 30 m ² / g, it becomes difficult to obtain sufficient fluidity even when used in combination with another fluidity-imparting agent. Further, the dispersion of the fluidity-imparting agent tends to be insufficient, and fogging occurs in the image.

Further, even in the range of 30 to ²⁰⁰ m ² / g, adverse effects occur unless used in combination with hydrophobic silica. In the range of 30 to 100 m ² / g, the use of only alumina or titanium oxide results in insufficient fluidity, so it is necessary to use it together with hydrophobic silica having a high fluidity-imparting effect. Further, in the range of 100 to 200 m ² / g, the surface of the colorant-containing fine particles can be uniformly covered, so that the use of only low-charged alumina or titanium oxide results in an excessively low charge amount. Therefore, it is necessary to use in combination with negatively charged hydrophobic silica.

As described above, in terms of negative chargeability and fluidity-imparting ability, hydrophobic silica functions to supplement alumina and titanium oxide. Therefore, if the BET specific surface area is not less than 80 m ² / g, sufficient function cannot be obtained. More preferably, it is 150 m ² / g or more.

By using alumina, titanium oxide and hydrophobic silica together as in the constitution of the present invention, not only the above-mentioned control of the charge amount but also other adverse effects associated with the reduction in the particle size of the toner are improved.

When the particle size of the toner is reduced, the Coulomb force and Van der Waals force acting on the toner become relatively stronger than the gravitational force and the inertial force, so that the adhesive force between the toners becomes stronger, and toner aggregates are easily generated. Become. On the other hand, alumina and titanium oxide weaken the adhesive force due to charging and make it difficult to form toner aggregates. Also, when the particle size of the toner is reduced, the number of contact points between the toner and the carrier increases, and carrier spent tends to occur. On the other hand, alumina and titanium oxide also serve as good spacers between the carrier and the toner and exert a good effect.

Furthermore, when alumina, titanium oxide and hydrophobic silica are used in combination, the fluidity of the toner becomes better and the mixing property of the developer and the toner cleaning property become better than when each is used alone.

Further, in the present invention, magnetic particles coated with a styrene-acrylic copolymer crosslinked with a derivative containing a triazine ring are used as the magnetic particles. Heretofore, there have been several patent application examples of the same magnetic particles (for example, Japanese Patent Application Laid-Open No. 60-57352). However, the present inventors have proposed magnetic particles that are very suitable for toners having a small particle diameter. Something has been found.

By the action of the derivative containing a triazine ring in the coating resin, the ability to impart a charge to the negatively chargeable toner is enhanced. Further, the strength of the coating layer is increased by the crosslinking, and the magnetic particles have good durability. Since the magnetic particles have an increased charge-imparting ability, the charge amount of the toner is likely to be excessive. However, in the present invention, the charge amount can be controlled to an appropriate value by adjusting the addition amount of alumina and titanium oxide. By this combination, fog can be greatly improved while maintaining the image density as before. Also, toner scattering was significantly improved. It is considered that this result is due to the fact that the charge amount distribution of the toner became sharper and the toner having a low charge amount decreased. Although the cause of the sharpening of the charge amount is not clear, it is considered to be due to the uniformity of the coating and the increase in the number of charge sites.

As described above, the scattering of the toner tends to occur when the particle size of the toner is reduced, but is improved by adopting the configuration of the present invention. Also, as for fog, since the carrier spent becomes easier to progress by reducing the particle size of the toner, fogging becomes easier. However, this can be improved as well.

The developer used in the present invention includes magnetic particles and toner particles, and each constituent material will be described below.

(1) Toner Particles Colorant-Containing Resin Particles As the binder substance used for the colorant-containing resin particles, various material resins conventionally known as toner binder resins for electrophotography are used.

For example, styrene diameter copolymers such as polystyrene, styrene / butadiene copolymer, styrene / acrylic copolymer, and ethylene copolymers such as polyethylene, ethylene / vinyl acetate copolymer, and ethylene / vinyl alcohol copolymer , Phenolic resin, epoxy resin, acrylic phthalate resin, polyamide resin, polyester resin,
Maleic acid resin and the like. In addition, the production method of any resin is not particularly limited.

Among these resins, polyester resins are suitable for the present invention. Polyester resins have excellent fixing properties and are suitable for color toners, but have a strong negative charging ability and tend to be excessively charged. Therefore, when the polyester resin is used in the present invention, adverse effects are improved, and an excellent toner is obtained.

In particular, (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2
~ 10. A) a carboxylic acid component comprising a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, phthalic acid) Acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) are more preferred because they have sharp melting properties.

In particular, from the viewpoint of light transmission with a trapene, the apparent viscosity at 90 ° C. is 5 × 10 ^{4 to} 5 × 10 ⁶ poise, preferably 7.5 × 10 ⁴ poise.
２2 × 10 ⁶ poise, more preferably 10 ⁵ to 10 ⁶ poise, and the apparent viscosity at 100 ° C. is 10 ^{4 to} 5 × 10 ⁵ poise, preferably 10 ^{4 to} 3.0 × 10 ⁵ poise, more preferably 10 ⁴ to 2
Color O with good light transmittance due to × 10 ⁵ poise
As a result, good results can be obtained in fixing property, color mixing property and high-temperature offset resistance as a full-color toner. 90 ℃
The absolute value of the difference between the apparent viscosity P ₂ at apparent viscosity P ₁ and 100 ° C. in ^{the, 2 × 10 5 <| P} 1 -P 2 | < particularly preferably in the range of 4 × 10 ^6.

As the coloring agent, known dyes and pigments, for example, phthalocyanine blue, induslen blue, peacock blue, permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow and the like can be used widely. The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to be sensitive to the light transmittance of the OHP film.

Fluidity improver Two kinds of fluidity improvers used in the present invention are used in combination.One of them uses alumina or titanium oxide having a surface area of 30 m ² / g or more as measured by the BET method. One type uses 80 m ² / g or more of hydrophobic silica as measured by the specific surface area by the BET method.

Alumina and titanium oxide can be relatively easily obtained in a fine particle size by a gas phase method, but there are no particular restrictions on the production method. The surface hydrophobization treatment may or may not be performed. There is no particular restriction on the crystal structure.

Hydrophobic silica having a degree of hydrophobicity of at least a certain degree has a greater fluidity-imparting effect and is more favorable, but there is no particular limitation when used in the present invention.

The application amount of the fluidity improver is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the colorant-containing resin particles. If the amount is less than 0.01 part by weight, there is no effect in improving the fluidity. If the amount is more than 10 parts by weight, fogging and bleeding of characters and scattering in the machine are promoted. In particular, in the case of a color toner, when an OHP image is formed, the sharpness of color is lost.

Charge Control Agent A charge control agent may be added to the toner according to the present invention in order to stabilize charging characteristics. At that time, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferable.
In the present invention, when a negatively charged developer is used, the present invention becomes more effective. In this case, as the negatively charge controlling agent, for example, a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex of di-tert-butylsalicylic acid or Organometallic complexes such as zinc complex). When the negative charge control agent is added to the toner, it is added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the binder resin.

(2) Magnetic particles The magnetic particles used in the present invention include, for example, iron, nickel, copper, zinc, cobalt, and the like, which are not oxidized or surface oxidized.
Metals such as manganese, chromium, and rare earths and alloys or oxides thereof and ferrites can be used. In addition, there is no particular limitation on the manufacturing method.

In the present invention, the surface of the magnetic particles is coated with a resin or the like.A method of dissolving or suspending a coating material such as a resin in a solvent and applying the coating material to adhere to the magnetic particles, or simply a powder method Any of the conventionally known methods, such as a method of mixing with, for example, can be applied. In order to stabilize the coating layer, it is preferable that the coating material be dissolved in a solvent.

As the coating material on the surface of the magnetic particles, a copolymer obtained by polymerizing at least one monomer selected from styrene monomers and at least one monomer selected from acrylic monomers is used. A resin obtained by cross-linking the union with a derivative containing a triazine ring is used.

Examples of the styrene resin include, for example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-vinyl acetate copolymer, and the like.
Acrylic ester copolymers (methyl acrylate copolymer, ethyl acrylate copolymer, butyl acrylate copolymer, octyl acrylate copolymer, phenyl acrylate copolymer, 2-ethylhexyl acrylate copolymer, etc.) And methacrylate copolymers (eg, methyl methacrylate copolymer, ethyl methacrylate copolymer, butyl methacrylate copolymer, phenyl methacrylate copolymer).

Derivatives containing a triazine ring include, but are not limited to, hexamethoxymelamine and butylated melamine.

The most suitable material for the magnetic particles used in the present invention is 98% or more of Cu—Zn—Fe (composition ratio (5 to 20): (5 to 20%).
20): Ferrite particles having a composition of (30 to 80)), which are easy to smoothen the surface and have a stable charging ability,
In addition, the coating can be stabilized. As a coating material used for this, an acrylic resin or a styrene-acrylic resin copolymer is used for the positively charged compound, and a silicone resin, polyvinylidene fluoride-polytetrafluoroethylene copolymer is used for the negatively charged compound. It is best to use

The coating amount of the compound may be appropriately determined so that the magnetic particles satisfy the above conditions, but is generally 0.1 to 30% by weight (preferably 0.3 to 20% by weight) based on the magnetic particles of the present invention. .

These magnetic particles preferably have a weight average particle size of 35 to 65 μm, preferably 40 to 60 μm. Furthermore, the weight distribution of 35 μm or less is 1 to 5% and the weight distribution of 35 μm
A good image can be maintained when the distance between 5 μm and 43 μm is 5% or more and 20% or less and 74 μm or more is 2% or less.

In the present invention, when the mixing ratio of the magnetic particles and the toner particles is set to 2.0% by weight to 12% by weight, preferably 3% by weight to 9% by weight as the toner concentration in the developer, usually good results can be obtained. When the toner density is less than 2.0%, the image density is low and it is not practically added. When the toner density is more than 12%, fog and scattering inside the machine are increased, and the useful life of the developer is shortened.

Hereinafter, each of the measurement methods (1) to (4) relating to the characteristic value of the developer used in the present invention will be described.

(1) Particle size distribution measurement: Coulter counter TA-II type (manufactured by Coulter, Inc.) was used as a measuring device, and an interface (manufactured by Nikkaki) for outputting a number average distribution and a volume average distribution, and a CX-1 personal computer (manufactured by Canon) ) And the electrolyte is 1
Prepare a 1% aqueous NaCl solution using graded sodium chloride.

As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 0.5 to 50 mg of a measurement sample is further added.

The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the above-mentioned Coulter Counter TA-II was used.
The particle size distribution of the 0 μm particles is measured to obtain a volume average distribution and a number average distribution.

From the obtained volume average distribution and number average distribution, respective values of volume average particle diameter, number average distribution of 5.04 μm or less, and volume average distribution of 16.0 μm or more are obtained.

(2) Measurement of triboelectric charge: FIG. 1 is an explanatory diagram of a triboelectric charge measuring device.

First, a mixture of particles to be measured and magnetic particles used as a developer is prepared. The mixing ratio is 1 part by weight to 9 parts by weight of the magnetic particles in the case of the toner and the colorant-containing fine particles, and 2 parts by weight to 98 parts by weight of the magnetic particles in the case of the fluidity-imparting agent. .

The particles to be measured and the magnetic particles are placed in a measurement environment and left for 12 hours or more, then put into a polyethylene bottle, and sufficiently mixed and stirred.

Next, a mixture of particles and magnetic particles whose triboelectric charge amount is to be measured is placed in a metal measuring container 2 having a conductive screen 3 of 500 mesh (which can be appropriately changed to a size that does not allow magnetic particles to pass) at the bottom. A metal lid 4 is provided. At this time, the weight of the entire measurement container 2 is weighed and defined as W ₁ (g). next,
In the suction device 1 (at least a portion in contact with the measuring container 2 is an insulator), the pressure of the vacuum gauge 5 is adjusted to 250 mmAq by adjusting the air volume control valve 6 by suctioning from the suction port 7. In this state, suction is sufficiently performed (about 2 minutes) to remove toner by suction. The potential of the electrometer 9 at this time is set to V (volt). Where 8
Is a capacitor and the capacity is C (μF). Also,
The weight of the whole measuring container after suction is weighed and is defined as W ₂ (g). This triboelectric charge amount T (μC / g) is calculated as in the following equation.

(3) Apparent viscosity measurement: Use a flow tester CFT-500 type (manufactured by Shimadzu Corporation). The sample weighs about 1.0 to 1.5 g of a 60mesh pass product. This is pressed for 1 minute at a load of 100 kg / cm ² using a molding machine.

The pressurized sample is subjected to a flow tester measurement under the following conditions under normal temperature and normal humidity (temperature: about 20 to 30 ° C., humidity: 30 to 70% RH) to obtain a humidity-apparent viscosity curve. From the obtained smooth curve, the apparent viscosities at 90 ° C. and 100 ° C. are determined and are defined as the apparent viscosities for the temperature of the sample.

PATE TEMP 6.0 D / M (° C for 1 minute) SET TEMP 70.0 DEG (° C) MAX TEMP 200.0 DEG INTERVAL 3.0 DEG PREHEAT 300.0 SEC (seconds) LOAD 20.0 KGF (kg) DIE (DIA) 1.0 MM (mm) DIE (LENG) 1.0 MM PLUNGER 1.0 CM ² (cm ² ) (4) Measurement of toner scattering amount A developing unit (for Canon CLC-1) is fixed to an idle rotating machine, and a plate with a known weight is centered directly under the sleeve of the developing unit. (AS version large), and rotate the sleeve and the screw in the developing unit at a sleeve peripheral speed of 210 mm / sec for 10 minutes. At this time, the weight of the toner scattered on the plate is measured. The measurement environment is 32.5 ° C / 85% RH, and the developer is 12
Use the one that has been left for more than an hour.

[Examples] In the examples, "%" indicates% by weight, and "parts" indicates parts by weight.

Example 1 Polyester resin obtained by condensation of propoxylated bisphenol and fumaric acid 100 parts Phthalocyanine pigment 5 parts Chromium complex salt of J-tert-butylsalicylic acid 4 parts was sufficiently premixed with a Henschel mixer,
The mixture was melt-kneaded at least twice with a three-roll mill, cooled, and coarsely ground to a particle size of about 1 to 2 mm using a hammer mill. Next, it was pulverized by a pulverizer using an air jet method. Furthermore, the obtained finely pulverized material is classified to 2 to 10 μm.
m, a colorant-containing resin particle having a volume average particle size of 7.8 μm was obtained.

The apparent viscosity of the particles is 6.00 × 10 ⁵ poise at 90 ° C., 100
It was 1.1 × 10 ⁴ poise at ° C.

100 parts of the above colorant-containing resin particles have a specific surface area of 100 m ² / g by BET method 0.5 parts of alumina fine powder and a specific surface area of 250 m ² / g by BET method and silica subjected to hydrophobic treatment with hexamethyldisilazane 0.5 parts of the fine powder was combined and externally added to obtain a cyan toner.

6 parts of this cyan toner was coated on the surface with a resin obtained by crosslinking a styrene-acrylic copolymer (3: 6: 1) composed of styrene, methyl methacrylate and 2-hydroxyethyl acrylate with hexamethoxymethyl melamine.
A developer was prepared by mixing 94 parts of -Zn-Fe-based ferrite particles.

Table 1 shows the charge amount of this toner in a low temperature and low humidity environment (15 ° C., 10% RH) and the charge amount in a high temperature and high humidity environment (32.5 ° C., 85% RH).

Using this developer, a commercial plain paper copier (CLC-1 Canon) was used to run a 30,000-sheet running test at room temperature and normal humidity (23 ° C, 60% RH), low temperature and low humidity (15 ° C, 10% RH), As a result of performing in each environment of high temperature and high humidity (32.5 ° C., 85% RH), a high-moisture image having a sufficient image density was obtained in any environment.

Comparative Example 1 As a fluidity imparting agent, the specific surface area by the BET method was 100 m ² / g.
Example 1 was repeated except that only 0.8 part of silica fine powder hydrophobized with dimethylchlorosilane was used.
As a result, the image density was lowered under low temperature and low humidity, and became more remarkable as the copying running progressed.

Comparative Example 2 As a fluidity imparting agent, the specific surface area by the BET method was 120 m ² / g
Example 1 was repeated except that only 0.7 part of the alumina fine powder was used. As a result, the toner was scattered significantly during copying running, and the image was fogged. Thereafter, the toner density was reduced to 4%, and the same operation was carried out. However, toner scattering and fog were at unsatisfactory levels.

Comparative Example 3 As a fluidity imparting agent, the specific surface area by the BET method was 20 m ² / g
0.6 parts of alumina fine powder and specific surface area by BET method of 25
0 m ² / g, and the same procedure as in Example 1 was carried out except that 0.5 part of silica fine powder hydrophobized with hexamethyldisilazane was used, the mixing state with the magnetic particles was poor. As a result, toner particles that were not sufficiently triboelectrically charged were generated, and fogging became noticeable in the image after about 500 copies had been run. After that, since the control of the toner concentration became unstable, the running test was stopped.

Example 2 Polyester resin obtained by condensing propoxylated bisphenol and terephthalic acid 100 parts Low molecular weight polypropylene 2 parts Chromium complex salt of di-tert-butylsalicylic acid 4 parts Rhodamine pigment 3 parts Volume average particle size 6.5μm
Red powder was obtained. In the above powder, as a fluidity imparting agent,
Alumina fine powder 0.4 having a specific surface area of 95 m ² / g by BET method
And 0.4 part of a silica fine powder having a specific surface area of 150 m ² / g and a hydrophobized treatment with dimethyldichlorosilane was externally added to obtain a toner.

To 6 parts of the above toner, 94 parts of ferrite particles coated with a resin obtained by cross-linking a copolymer (5: 2: 3) of styrene, methyl methacrylate and 2-ethylhexyl acrylate with butylated melamine were mixed, and a developer was prepared. And

Using this developer, a commercially available plain paper copier (NP-COLO)
RT (manufactured by Canon Inc.), a running test of 10,000 sheets was performed in the same environment as in Example 1, and high-density and high-quality images were obtained.

Example 3 As a fluidity imparting agent, the specific surface area by the BET method was 40 m ² / g.
The titanium oxide fine powder hydrophobized with octyltrimethoxysilane and the silica fine powder having a specific surface area of 250 m ² / g by BET method and hydrophobized with hexamethyldisilazane were used. Example 1 except for
As a result, a high-density, high-quality image was obtained in any environment.

Example 4 CI Pigment Yellow Instead of Phthalocyanine Pigment
Using 17 parts of 3.5 parts of 7.5 μm yellow toner, CI solvent red 49 of 0.9 parts and CI solvent 52 of 1.0 part of 7.6 μm of magenta toner, CI pigment yellow 1
7 parts, 1.2 parts of CI Pigment Red 5 and 1.5 parts of CI Pigment Blue 15 were used to prepare a 7.5 μm black toner. Using the magnetic particles used in Example 1 together with the cyan toner and performing image output with a CLC-1 (Canon) remodeling machine, a good full-color image was obtained, and the toner stain in the machine was also reduced. I didn't look.

Comparative Example 4 Same as Example 4 except that a styrene-acrylic copolymer resin was used as a binder resin, and only silica fine powder hydrophobized with hexamethyldisilazane was used as a fluidity-imparting agent. A developer was prepared.

Using this developer, an unfixed image was formed with CLC-1 (manufactured by Canon) and fixed with a fixing tester. However, the color reproducibility was poor even when the temperature, speed, etc. were adjusted to optimal conditions.

Comparative Example 5 As magnetic particles, styrene, methyl methacrylate,
Copolymer of 2 hydroxyethyl acrylate (3:
6: 1) CU-Zn-F coated with resin not crosslinked
A good image was obtained in the same manner as in Example 4 except that e-type ferrite particles were used and the external addition amount of alumina fine powder was changed to 0.3 part, but a good image was obtained. When the inside of the machine was observed after running 30,000 sheets, the inside of the machine was particularly contaminated with magenta toner.

[Effects of the Invention] According to the present invention, an image having high image quality and good color reproducibility can be obtained, and good environmental characteristics can be exhibited even with environmental fluctuations.

[Brief description of the drawings]

 FIG. 1 is an explanatory diagram of a triboelectric charge amount measuring device.

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Claims (2)

(57) [Claims] 1. A toner comprising a non-magnetic colorant-containing fine particle, a toner comprising a fluidity-imparting agent and a magnetic particle, wherein the colorant-containing fine particle has a negative charge and a volume average particle diameter of 4 to 4.
Alumina and / or titanium oxide having a specific surface area of 30 to 200 m ² / g according to the BET method, and a specific surface area of 8 μm according to the BET method.
A styrene-acrylic copolymer crosslinked with a derivative containing a triazine ring is used in combination with a hydrophobic silica having a particle size of 0 m ² / g or more, and as a coating resin for the magnetic particles. Developer for electrostatic charge development. 2. The developer according to claim 1, wherein the binder resin of the colorant-containing fine particles mainly comprises a polyester resin.