JP4384961B2 - Yellow toner - Google Patents

Description

  The present invention relates to a yellow toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a two-component developer containing the yellow toner.

  Conventionally, as a yellow toner for color electrophotography, a toner containing a dichlorobenzidine pigment such as C.I. Pigment Yellow 17 as a colorant has been used. However, since dichlorobenzidine pigments are listed as one of the regulations of Blue Angel, the German Eco Mark, development of yellow toners using colorants that do not have a dichlorobenzidine skeleton is expected. .

  Thus, a toner containing C.I. Pigment Yellow 180 has been reported (see Patent Documents 1 and 2), but the pigment has a great influence on the chargeability, and a sufficient charge amount cannot be obtained. Also, a toner using C.I. Pigment Yellow 180 in combination with a specific charge control agent has been reported (see Patent Document 3).

On the other hand, although a toner containing CI Pigment Yellow 185 has been reported (see Patent Document 4), the effect on the charging property of the pigment is large, and an appropriate charge amount as a toner cannot be obtained. A toner using a specific charge control agent for CI Pigment Yellow 185 has been reported (see Patent Document 5).
JP-A-6-230607 (Claim 1) JP-A-6-266163 (Claim 1) JP-A-8-209017 (Claims 1 and 7) Japanese Patent Laid-Open No. 6-18715 (Claim 1) JP 2001-66825 A (Claim 1)

  An object of the present invention is to provide a yellow toner having a good yellow color with high saturation, capable of stably maintaining an appropriate charge amount even in high-speed continuous printing, and capable of suppressing toner scattering, and the yellow toner An object of the present invention is to provide a two-component developer containing toner.

The present invention
[1] A yellow toner containing a binder resin and a colorant, wherein the colorant contains CI pigment yellow 185 and CI pigment yellow 139, and [2] the [1] And a two-component developer containing a yellow toner and a carrier.

  The yellow toner and the two-component developer of the present invention have a high saturation and a good yellow color, can stably maintain an appropriate charge amount even in high-speed continuous printing, and can suppress toner scattering. It has an excellent effect of being able to.

  The toner of the present invention contains at least a binder resin and a colorant, and has one feature in that the colorant contains C.I. Pigment Yellow 185 and C.I. Pigment Yellow 139.

  CI Pigment Yellow 185, which is a kind of isoindoline-based pigment, has a cyano group that is electron-withdrawing, so it is difficult to control charging due to its negative chargeability, and even when used in combination with a charge control agent, Since the charging characteristics are not stable, toner scatters easily around the developing machine, and this is particularly noticeable when a two-component developing system exceeding a linear speed of 200 mm / sec or more is used in a high-speed machine.

  Such a problem in the high-speed developing device is caused by the fact that the developing process speed is fast and the replenished toner is not sufficiently agitated, so that the toner with the high charge amount maintained is sent to the developing unit. It is estimated to be. That is, a toner with a high charge amount is difficult to be developed on the photoreceptor and is firmly attached to the carrier surface by Coulomb force. As a result, other toners are prevented from contacting the carrier surface. Presumed to occur.

  However, when the present inventors have used CI Pigment Yellow 185, which is the same isoindoline pigment as CI Pigment Yellow 185, the detailed reason is unknown, but charging of the toner containing CI Pigment Yellow 185 is not possible. It has been found that not only the characteristics are stable and toner scattering is improved, but also an ideal yellow color with high saturation can be obtained.

  Compounds classified as C.I. Pigment Yellow 185 have the formula (Ia):

It is represented by

  Examples of commercially available C.I. Pigment Yellow 185 include “Paliotol Yellow D1155” (manufactured by BASF).

  Compounds classified as C.I. Pigment Yellow 139 have the formula (Ib):

It is represented by

  Examples of commercially available C.I. Pigment Yellow 139 include “Paliotol Yellow D1819” (manufactured by BASF).

  The weight ratio of CI Pigment Yellow 185 to CI Pigment Yellow 139 (CI Pigment Yellow 185 / CI Pigment Yellow 139) is preferably 99/1 to 70/30 from the viewpoint of chargeability and color reproducibility. / 1 to 80/20 is more preferable, and 99/1 to 90/10 is more preferable.

  The total content of CI Pigment Yellow 185 and CI Pigment Yellow 139 is preferably 1 to 15 parts by weight, more preferably 1 to 10 parts by weight, and 1 to 6 parts by weight with respect to 100 parts by weight of the binder resin. Further preferred.

  In the colorant, a colorant other than CI Pigment Yellow 185 and CI Pigment Yellow 139 may be appropriately contained as long as the effect of the present invention is not impaired, but CI Pigment Yellow 185 in the colorant may be contained. And CI Pigment Yellow 139 is preferably 80% by weight or more, and more preferably 90% by weight or more.

  Examples of the binder resin in the present invention include known resins used for toners, such as polyester, styrene-acrylic resin, epoxy resin, polycarbonate, polyurethane, and the like. Among them, polyester and styrene-acrylic copolymer are used. Preferably, polyester is more preferable from the viewpoints of colorant dispersibility, fixability, and durability. The content of the polyester is preferably 50% by weight or more, more preferably 80% by weight or more, and further preferably 100% by weight in the binder resin.

  As a raw material monomer for polyester, a known divalent or higher valent alcohol component and a known carboxylic acid component such as a divalent or higher carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.

  As the alcohol component, the formula (II):

(Wherein R ¹ is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers, and the sum of x and y is 1 to 16, preferably 1.5 to 5.0) It is preferably contained.

  Examples of the compound represented by the formula (I) include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) Examples include bisphenol A alkylene (carbon number 2 to 3) oxide (average added mole number 1 to 16) adducts such as propane. Other alcohol components include ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethyloglycol propane, hydrogenated bisphenol A, sorbitol, or their alkylene (2 to 4 carbon atoms) oxide (average added mole number 1 -16) Additives etc. are mentioned, and it is preferable to contain one or more of these.

  The content of the compound represented by the formula (I) is preferably 5 mol% or more, more preferably 50 mol% or more, further preferably 80 mol% or more, and particularly preferably 100 mol% in the alcohol component.

  As the carboxylic acid component, dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid and maleic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octyl succinic acid, or those having 2 to 20 carbon atoms. Examples thereof include succinic acid, trimellitic acid, pyromellitic acid substituted with an alkenyl group, anhydrides of these acids, and alkyl (1 to 3 carbon atoms) esters of these acids, which contain one or more of these. Those are preferred.

  Further, the alcohol component and the carboxylic acid component may appropriately contain a monovalent alcohol or a monovalent carboxylic acid compound from the viewpoint of adjusting the molecular weight.

  The polyester can be produced, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst.

  It is preferable that the softening point of the polyester is 95 to 160 ° C., the glass transition point is 50 to 75 ° C., the acid value is 1 to 40 mgKOH / g, and the hydroxyl value is 3 to 60 mgKOH / g.

  Further, the toner of the present invention includes a charge control agent, a release agent, a fluidity improver, a conductivity modifier, an extender, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, and an improved cleaning property. An additive such as an agent may be appropriately contained.

  A known charge control agent can be used as the charge control agent. For example, chromium / azo complex dyes; iron azo complex dyes; cobalt / azo complex dyes; metal compounds of salicylic acid or derivatives thereof; chromium / zinc / aluminum / boron complexes or salt compounds of naphtholic acid or derivatives thereof; benzylic acids or derivatives thereof Chromium / zinc / aluminum / boron complexes or salt compounds; surfactants such as long chain alkyl / carboxylates, long chain alkyl / sulfonates, nigrosine dyes and derivatives thereof, triphenylmethane derivatives, quaternary ammonium salts And derivatives of quaternary phosphonium salts, quaternary biridinium salts, guanidine salts, amidine salts, and the like.

  Among the charge control agents, since the toner of the present invention is a yellow toner, a white charge control agent is preferable. From the viewpoint of the hue and chargeability of the charge control agent, the formula (III):

Wherein R ² , R ³ and R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group or alkenyl group having 1 to 10 carbon atoms, M is zinc, zirconium, chromium, aluminum, Copper, nickel or cobalt, m is an integer of 2 or more, and n is an integer of 1 or more)
A metal compound of a salicylic acid derivative represented by The metal compound of the salicylic acid derivative may be either a metal salt or a metal complex, or may be a single compound or two or more compounds may be used in combination.

In the formula (III), R ³ is preferably a hydrogen atom, and R ² and R ⁴ are preferably a branched alkyl group, more preferably a tert-butyl group.

  As M, zinc and chromium are preferable because of their high electronegativity and good charging effect.

As a commercially available product suitably used in the present invention, wherein R ³ is a hydrogen atom and R ² and R ⁴ are tert-butyl groups, “Bontron E-84” (M: zinc, manufactured by Orient Chemical Industries, Ltd.) "TN-105" (M: Zirconium, manufactured by Hodogaya Chemical Co., Ltd.), "Bontron E-81" (M: Chrome, manufactured by Orient Chemical Industry Co., Ltd.), "Bontron E-88" (M: Aluminum, manufactured by Orient Chemical Co., Ltd.) and the like.

  The content of the charge control agent is preferably 0.1 to 10 parts by weight and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the binder resin. In particular, in the present invention, charge control of isoindoline-based pigments (CI Pigment Yellow 185 and CI Pigment Yellow 139) is important. From the viewpoint of charge amount and stability, the charge control agent and the isoindoline-based pigments are used. The weight ratio (charge control agent / isoindoline pigment) is preferably 99/1 to 30/70, more preferably 99/1 to 50/50.

  As release agents, polyolefin waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax, carnauba wax, ester waxes such as beeswax, beeswax, whale wax, montan wax, rice wax, fatty acid amide waxes And petroleum waxes such as amide wax, paraffin wax, microcrystalline wax, petrolatum, and the like. These may be used alone or in combination of two or more. The content of the release agent is preferably 0.1 to 20 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

The toner of the present invention may be any toner such as pulverized toner, polymerized toner, and capsule toner. For example, as a general method for producing a pulverized toner, a binder resin, a colorant, and an additive such as a charge control agent are uniformly mixed with a mixer such as a Henschel mixer or a ball mill, and then a sealed kneader or a single screw. Or the method of melt-kneading with a biaxial extruder etc., cooling, grind | pulverizing, and classifying is mentioned. The toner of the present invention preferably has a volume-median particle size (D ₅₀ ) of 3 to 10 μm. In the present invention, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  Further, the toner and the external additive are stirred and mixed with a high-speed stirrer such as a super mixer or a Henschel mixer, and the external additive is added to the toner surface of the present invention by a method such as attaching the external additive to the toner surface. It may be added.

  Examples of the external additive in the present invention include inorganic fine particles such as silicon dioxide (silica), titanium dioxide, aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, and tin oxide. From the viewpoint of imparting chargeability, silica and titanium dioxide are preferable, and silica is more preferable. The inorganic fine particles can be used alone or in combination of two or more. In the present invention, at least one of the inorganic fine particles used as an external additive is an organic silicon having an organic group such as a trimethyl group. What was hydrophobized with the compound is preferable.

  The average particle diameter of the inorganic fine particles is preferably 1 to 200 nm, more preferably 5 to 100 nm, and further preferably 5 to 80 nm from the viewpoints of chargeability and fluidity. In the present invention, the particle size of the inorganic fine particles is determined using a scanning electron microscope or a transmission electron microscope. Examples of such commercially available inorganic fine particles include “AEROSIL R972” (Nippon Aerosil, hydrophobic silica, average particle size: 16 nm), “AEROSIL R974” (Nippon Aerosil, hydrophobic silica, average particle size: 12 nm).

  Since the toner of the present invention can stably maintain an appropriate charge amount even in high-speed continuous printing, it can be suitably used as a one-component developing toner that strongly requires the charging ability of the toner itself. Therefore, it is also effective for suppressing toner scattering in the two-component development system where toner scattering is a problem. Therefore, from the viewpoint of the polarity of two-component developing toners, particularly resins and charge control agents, for negatively chargeable two-component developing. It can also be suitably used as a toner. Accordingly, the present invention further provides a two-component developer containing the toner of the present invention and a carrier.

In the present invention, from the viewpoint of image characteristics, it is preferable to use a carrier with low saturation magnetization that weakens the area around the magnetic brush. Saturation magnetization of the carrier is preferably ^{40~100Am 2 / kg, 50~90Am 2 /} kg is more preferable. The saturation magnetization is preferably 100 Am ² / kg or less from the viewpoint of adjusting the hardness of the magnetic brush and maintaining gradation reproducibility, and preferably 40 Am ² / kg or more from the viewpoint of preventing carrier adhesion and toner scattering.

  As the core material of the carrier, those made of known materials can be used without particular limitation, for example, ferromagnetic metals such as iron, cobalt, nickel, magnetite, hematite, ferrite, copper-zinc-magnesium ferrite, Examples include alloys and compounds such as manganese ferrite and magnesium ferrite, and glass beads. Among these, iron powder, magnetite, ferrite, copper-zinc-magnesium ferrite, manganese ferrite, and magnesium ferrite are preferable from the viewpoint of chargeability. From the viewpoint of image quality, ferrite, copper-zinc-magnesium ferrite, manganese ferrite and magnesium ferrite are more preferable.

  The surface of the carrier is preferably coated with a resin from the viewpoint of reducing carrier contamination. The resin that coats the carrier surface varies depending on the toner material. For example, fluororesin such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin such as polydimethylsiloxane, polyester, styrenic resin, Acrylic resins, polyamides, polyvinyl butyral, amino acrylate resins, and the like can be used, and these can be used alone or in combination of two or more. However, when the toner is negatively charged, the chargeability and surface From the viewpoint of energy, a silicone resin is preferable. The method for coating the core material with the resin is not particularly limited, for example, a method in which a coating material such as a resin is dissolved or suspended in a solvent and applied to the core material, or a method of simply mixing with a powder.

  In the two-component developer of the present invention obtained by mixing the toner and the carrier, the toner to carrier weight ratio (toner / carrier) is preferably 1/99 to 10/90, and 2/98 to 8/92. More preferred.

  The toner and the two-component developer of the present invention are suitable because the toner scattering is effectively suppressed even in a high-speed developing device having a linear speed of preferably 200 mm / sec or more, more preferably 200 mm / sec or more. Can be used. The linear speed of the developing device referred to in the present invention refers to the peripheral speed of the magnet roller.

[Softening point of resin]
Using a Koka type flow tester (CFT-500D, manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C / min. A nozzle with a thickness of 1 mm is pushed out, thereby drawing a plunger tester drop amount (flow value) -temperature curve of the flow tester, and when the height of the S-shaped curve is h, the temperature corresponding to h / 2 (resin The temperature at which half flows out) is taken as the softening point.

[Glass transition point of resin]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210) to raise the temperature to 200 ° C, and when the sample was cooled from that temperature to a temperature drop rate of 10 ° C / min. The temperature at the intersection of the extension of the baseline below the maximum peak temperature of the heat of fusion and the tangent showing the maximum slope from the peak rising portion to the peak apex is defined as the glass transition point of the resin.

[Resin acid value]
Measured by the method of JIS K0070.

Resin production example 1
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 1705g, terephthalic acid 328g, fumaric acid 1050g and dibutyltin oxide 2.5g equipped with nitrogen introduction tube, dehydration tube, stirrer and thermocouple The mixture was placed in a 5-liter four-necked flask, reacted at 230 ° C. for 8 hours, and further reacted at 8.3 kPa until a predetermined softening point was reached. The obtained resin had an acid value of 19 mgKOH / g, a hydroxyl value of 23 mgKOH / g, a softening point of 108 ° C., and a glass transition point of 60 ° C. The obtained resin is designated as polyester A.

Examples 1-3 and Comparative Examples 1-4
100 parts by weight of polyester A, colorant and charge control agent shown in Table 1, and polyolefin wax “High Wax NP-105” (Mitsui Chemicals, melting point: 140/148 ° C.) After mixing 2 parts by weight with a Henschel mixer Then, after melt-kneading with a twin-screw extruder, cooling, pulverization and classification using a collision plate pulverizer “Dispersion Separator” (manufactured by Nippon Pneumatic Industry Co., Ltd.), A toner having a diameter (D ₅₀ ) was obtained.

  To 100 parts by weight of the obtained toner, 0.6 parts by weight of hydrophobic silica “AEROSIL R972” (manufactured by Nippon Aerosil Co., Ltd., average particle size: 16 nm) was added, and the mixture was stirred with a 10 liter Henschel mixer for 3200 r / min for 180 seconds. The yellow toner was obtained by sieving with a mesh of 100 μm mesh.

Test Example 1 [Charge amount change]
3 g of toner and 47 g of silicone-coated ferrite carrier (average particle size: 65 μm) are placed in a 50 ml cylindrical plastic bottle, and the container is fixed in a tumbler shaker mixer, 90 r / min.
The toner charge amount after 1 minute, 2 minutes, 5 minutes, 10 minutes, 30 minutes, and 60 minutes after the start of stirring is q / m meter (Epping) Measured with The measurement results are shown in FIG.

Test Example 2 [Toner scattering]
Toner 3g coated ferrite carrier (average particle size: 65 .mu.m, saturation magnetization: 68Am ² / kg) 47g were placed in cylindrical polybottle of 50ml volume, the vessel was fixed in a tumbler shaker mixer, at a rate of 90r / min Rotated for 2 minutes to obtain a two-component developer.

  10 g of the obtained developer is attached to the magnet roller part of a modified development unit of a commercially available copying machine, and the dust suction part of the dust counter (P-5H2: manufactured by Shibata Kikai Co., Ltd.) is made to face the magnet roller. The toner was scattered when the magnet roller was installed and rotated at a peripheral speed of 200 mm / sec for 5 minutes. The evaluation results are shown in Table 1.

Test Example 3 [Hue]
48 g of each toner and 756 g of ferrite carrier were placed in a 1 liter cylindrical plastic bottle, the container was fixed in a turbula shaker mixer, and rotated at a speed of 90 r / min for 10 minutes to obtain a two-component developer.

The obtained developer is mounted on an electrophotographic recording apparatus, a solid image having an image density of 1.3 is printed, and a measurement light D ₅₀ and a viewing angle of 2 ° are measured using a color meter “SPM50” (manufactured by Gretag). L ^* value, a ^* value, b ^* value, C ^* value, and hue angle were measured under the conditions. The results are shown in Table 1.

  From the measurement results of the charge amount and the toner scattering, the toners of Examples 1 to 3 have the charge amount maintained at an appropriate level (-18 to -23 μC / g) and the toner scattering is small, whereas CI pigment The toner of Comparative Example 1 containing only yellow 185 has a high charge amount at the initial stage of stirring and a large amount of toner scattering. These are not improved even in the toner of Comparative Example 2 in which a charge control agent is used in combination. Further, the toner of Comparative Example 3 containing only C.I. Pigment Yellow 139 has a low charge amount and a large amount of toner scattering. The toner of Comparative Example 4 containing C.I. Pigment Yellow 180 has a low charge amount and a large amount of toner scattering.

  Further, from the viewpoint of hue, the hue angles of the toners of Examples 1 to 3 are close to an ideal yellow color and show high saturation values, whereas only CI pigment yellow 185 and 180 are used. The toners of Comparative Examples 1 to 3 have a large hue angle (green as a hue), are not ideal yellow colors, and have low saturation. Further, the toner of Comparative Example 4 using only C.I. Pigment Yellow 139 has high saturation, but has a small hue angle (redness as a hue), and is not an ideal yellow color.

  The yellow toner of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

FIG. 1 is a graph showing measurement results of the toner charge amount in Test Example 1.

Claims (5)

A yellow toner comprising a binder resin and a colorant, wherein the colorant comprises CI pigment yellow 185 and CI pigment yellow 139 in a weight ratio of 99/1 to 70/30 (CI pigment yellow 185 / CI Pigment yellow 139) yellow toner (although which comprises at, L ^* a ^* b ^* and a ^* is less than 0 infrared absorbing agent in the color system, and CI Pigment yellow 185 and CI Pigment yellow 139 Except for yellow toner for light fixing containing at least a binder resin) . Yellow toner according to claim 1 Symbol placement total content of 1 to 15 parts by weight per 100 parts by weight of the binder resin of CI Pigment Yellow 185 and CI Pigment Yellow 139. Yellow toner according to claim 1 or 2, wherein the main component of the binder resin is a polyester. Further, as a charge control agent, the formula (III):

Wherein R ² , R ³ and R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group or alkenyl group having 1 to 10 carbon atoms, M is zinc, zirconium, chromium, aluminum, Copper, nickel or cobalt, m is an integer of 2 or more, and n is an integer of 1 or more)
In claim 1 to 3 yellow toner according to any one comprising a metal compound of salicylic acid derivative represented. Two-component developer comprising a yellow toner and a carrier in accordance with claim 1-4.

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