JP2008233184A - Toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner of a magenta tone having proper dispersibility of components, a balance in transparency and coloring power and proper color development properties. <P>SOLUTION: The toner contains a binder resin and a magenta pigment, and the minimum transmittance thereof at a wavelength of 500 to 600 nm is 25% or lower. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magenta toner that is particularly suitable for electrophotography, a copying machine using an electrostatic recording method, a printer, a fax machine, and the like.

In order to obtain a high-quality color image, the particle diameter of the toner to be used and the pigment contained in the toner is reduced, or the viscosity of the toner is reduced. In particular, it is an effective means to reduce the particle diameter of the pigment. For example, a toner in which the pigment is highly dispersed by adjusting the pigment fragmentation or the pigment addition amount is known (see Patent Document 1). ).
As described above, when each component including the pigment is highly dispersed in the toner, the transparency of the toner and the coloring power are balanced, and the quality such as color developability is improved, and a high-quality color image is obtained. .
JP 2003-173048 A

However, as described in Patent Document 1, when the pigment is subdivided, there are problems such as manufacturing technology and manufacturing cost. In addition, with regard to the amount of pigment added, when the amount added is small, the permeability is improved but the coloring power tends to decrease.On the other hand, when the amount added is increased, the manufacturing cost increases, and the coloring power is improved, but the permeability is high. There was a tendency to decrease. Thus, it was difficult to adjust the balance between transparency and coloring power.
Further, the transparency may be lowered depending on the combination of the toner components.

  Therefore, an object of the present invention is to realize a magenta toner having good dispersibility of components, a balance between transparency and coloring power, and good color development.

  As a result of intensive investigations, the present inventors have determined the minimum transmittance at a wavelength of 500 to 600 nm, thereby balancing the dispersion state of each component in the toner and the transparency and coloring power of the toner. As a result, the present invention was completed.

That is, the toner of the present invention is characterized by containing a binder resin and a magenta pigment and having a minimum transmittance of 25% or less at a wavelength of 500 to 600 nm.
Further, it preferably contains an ester wax.
Furthermore, it is preferable that a softening point is 95-120 degreeC.

  The magenta toner of the present invention has good component dispersibility, a balance between transparency and coloring power, and good color development.

  The toner of the present invention has a minimum transmittance of 25% or less at a wavelength of 500 to 600 nm. If the minimum transmittance is 25% or less, the dispersibility and color developability of the components constituting the toner described later can be made well-balanced. The minimum transmittance is preferably 0.1 to 20%.

The minimum transmittance of the toner can be obtained as follows.
First, the toner is sandwiched between two glass plates and heated and pressurized to prepare a sample in which the toner is melted to such an extent that the transparency can be confirmed. The heating temperature is preferably 100 to 115 ° C., and the pressing pressure is preferably 4 to 6 MPa.
Next, the absorbance of the sample is measured with a spectrophotometer.
The transmittance is obtained from the absorbance at a wavelength of 500 to 600 nm, and the smallest one is set as the minimum transmittance.

The toner of the present invention preferably has a softening point of 95 to 120 ° C., more preferably 100 to 115 ° C. When the softening point is less than 95 ° C, the heat resistant storage stability is deteriorated. On the other hand, when the softening point exceeds 120 ° C., the low-temperature fixability deteriorates.
In addition, a softening point can be calculated | required by a conventional method using a flow tester.

In order to obtain such a toner, the type and amount of each component may be adjusted. For example, as a component constituting the toner, in addition to the binder resin and the magenta pigment, an ester wax may be included as a release agent.
Hereinafter, each component will be described.

  Examples of the binder resin include thermoplastic resins such as polyester resins, vinyl chloride resins, polyamide resins, polyurethane resins, polyvinyl alcohol resins, vinyl ether resins, N-vinyl resins, and styrene-butadiene resins; Styrene resins, acrylic resins, styrene-acrylic resins, olefin resins such as polyethylene and polypropylene; bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, novolac type epoxy resins, polyalkylene ether type epoxy resins, cyclic Examples thereof include epoxy resins such as aliphatic epoxy resins and thermosetting resins such as cyanate resins. Of these, polyester resins are preferred. These binder resins may be used alone or in combination of two or more.

Examples of magenta pigments include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48, 48: 2, 48: 3, 48: 4, 57, 57: 1, 58, 60, 63, 64, 68, 81, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 163, 166, 169, 170, 177, 184, 185, 187, 202, 206, 207, 209, 220, 251, 254, etc .; C.I. I. Pigment violet 19 and the like. These magenta pigments may be used alone or in combination of two or more.
The content of the magenta pigment is preferably 2 to 20 parts by mass and more preferably 4 to 15 parts by mass with respect to 100 parts by mass of the binder resin. When the content of the magenta pigment is less than 2 parts by mass, the coloring power is lowered. On the other hand, if the content exceeds 20 parts by mass, the coloring power is increased more than necessary, making it difficult to reproduce a light magenta color.

The release agent further improves the release property from the fixing roll when the toner is used for electrophotography.
As the mold release agent, at least ester wax is used. Specific examples include carnauba wax. Of these, Carnauba No. 1 is preferred. These ester waxes may be used alone or in combination of two or more.
In the present invention, if at least an ester wax is used as the release agent, other waxes may be used alone or in combination of two or more. Examples of other waxes include polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene.

2-10 mass parts is preferable with respect to 100 mass parts of binder resin, and, as for content of a mold release agent, 3-8 mass parts is more preferable. When the content of the release agent is less than 2 parts by mass, it is difficult to obtain sufficient release properties. On the other hand, when the content exceeds 10 parts by mass, the heat resistant storage stability is deteriorated.
The proportion of the ester wax is preferably 60% by mass or more, preferably 75% by mass or more, and more preferably 100% by mass in 100% by mass of the release agent. If the ratio of the ester wax is 60% by mass or more, the minimum transmittance at a wavelength of 500 to 600 nm can be easily adjusted to 25% or less.

In addition to the components described above, the toner of the present invention may contain a charge control agent, an external additive, and the like as necessary.
The charge control agent further improves the chargeability of the toner, and various positive charge control agents and negative charge control agents can be used.
Examples of the positive charge control agent include pyridazine, pyrimidine, pyrazine, orthooxazine, metaoxazine, paraoxazine, orthothiazine, metathiazine, parathiazine, 1,2,3-triazine, 1,2,4-triazine, 1,3, 5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6-oxadiazine, 1,3,4-thiadiazine, 1,3,5-thiadiazine, 1,2,3 4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1,2,4,6-oxatriazine, 1,3,4,5-oxatriazine, phthalazine, quinazoline, Azine compounds such as quinoxaline; Azin Fast Red FC, Azin Fast Red 12BK, Azin Violet BO, Azin Brown G, azine light brown GR, azine dark green BH / C, azine deep black EW, azine deep black 3RL and other direct dyes; nigrosine compounds such as nigrosine, nigrosine salt, nigrosine derivatives; nigrosine BK, nigrosine NB, Acidic dyes comprising nigrosine compounds such as nigrosine Z; metal salts of naphthenic acid or higher fatty acids; alkoxylated amines; alkylamides; quaternary ammonium salts such as benzylmethylhexyldecylammonium and decyltrimethylammonium chloride; quaternary ammonium salts Examples thereof include resins or oligomers; resins or oligomers having a carboxylate salt; resins or oligomers having a carboxyl group. Among these, a resin having a quaternary ammonium salt or a quaternary ammonium salt is preferable. These positive charge control agents may be used alone or in combination of two or more.

  Examples of the negative charge control agent include an organometallic complex or a chelate compound, and examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and 3,5-ditertiary butyl salicylate chromium. These negative charge control agents may be used alone or in combination of two or more.

  The content of these charge control agents is preferably 0.5 to 15 parts by mass and more preferably 1 to 7 parts by mass with respect to 100 parts by mass of the binder resin. When the content of the charge control agent is less than 0.5 parts by mass, the charging ability is lowered, and the image tends to be fogged. On the other hand, if the content exceeds 15 parts by mass, the charging ability increases and the image density decreases.

Examples of the external additive include inorganic oxides such as silica, titanium oxide, and alumina, and metal soaps such as calcium stearate. Of these, silica is preferable. These external additives may be used alone or in combination of two or more.
The content of the external additive is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 2.5 parts by mass when the total of components other than the external additive is 100 parts by mass. When the content of the external additive is less than 0.1 parts by mass, the fluidity is lowered, and phenomena such as insufficient toner supply to the developing unit and insufficient charging occur. On the other hand, if the content exceeds 5 parts by mass, the amount of external additives becomes excessive, and the fixability is lowered.

The toner of the present invention can be produced according to a conventional method using each of the components described above.
As an apparatus used for production, for example, a mixer, a kneader, a classifier and the like can be used in appropriate combination.

  Thus, according to the toner of the present invention, by making the minimum transmittance at a wavelength of 500 to 600 nm to be 25% or less, the dispersibility of components such as pigments is good, and the color developability is improved. A high-quality image can be obtained.

  The toner of the present invention is particularly suitable as a developer for use in electrophotography, a copying machine using an electrostatic recording method, a printer, a fax machine, and the like, and a high-quality image can be obtained.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to a following example.
Here, each component used for the Example is shown below.

Pigment: Magenta pigment (manufactured by Clariant Japan, “Toner Magenta E-02”).
Mold release agent: ester wax (manufactured by Hiroyuki Kato, “refined carnauba wax”).
Mold release agent: Polyethylene wax (“High Wax 400P” manufactured by Mitsui Chemicals, Inc.).
Release agent: Polypropylene wax (manufactured by Sanyo Chemical Industries, Ltd., “Yumex 110TS”).
Charge control agent: quaternary ammonium salt (manufactured by Orient Chemical Industries, "P-51").
External additive: Silica (manufactured by Wacker, “H2050EP”).

In addition, the polyester resin obtained by the method shown below and the styrene-acrylic resin were used as the binder resin.
(Polyester resin)
4.0 mol of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane and 1.0 mol of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane And 4.5 mol of terephthalic acid, 0.5 mol of trimellitic anhydride and 4 g of dibutyltin oxide are reacted at 230 ° C. for 8 hours under a nitrogen atmosphere, and the softening point is 120 ° C. at 8.3 kPa. A polyester resin was obtained.
(Styrene-acrylic resin)
A monomer solution consisting of 70 parts by mass of styrene and 30 parts by mass of butyl acrylate was added to a polymerization initiator V-65 (2,2-azobis- (2,4-dimethylvaleronitrile), Wako Pure Chemical Industries, Ltd. (Manufactured) in a solution containing 6 parts by mass and 200 parts by mass of toluene as a solvent (with a condenser and refluxing toluene) was added dropwise over 3 hours. After the dropping, polymerization was carried out for 12 hours while maintaining the temperature at 60 ° C., and then toluene was distilled off under reduced pressure to obtain a styrene-acrylic resin.

[Example 1]
<Manufacture of toner>
A Henschel mixer (100 parts by mass of a polyester resin as a binder resin, 5.0 parts by mass of a magenta pigment, 5.0 parts by mass of an ester wax as a release agent, and 5.0 parts by mass of a charge control agent) After mixing for 5 minutes at a rotational speed of 2500 rpm using a Mitsui Mining Co., Ltd. “20B”), using a twin-screw kneader (Ikegai Co., “PCM-30”), the rotational speed is 200 rpm, the cylinder temperature is 120 ° C., The mixture was kneaded at an input amount of 6 kg / hour to obtain a kneaded product. Subsequently, using a drum flaker (manufactured by Mitsui Mining Co., Ltd.), the wind speed was adjusted to 140 mm / second and the plate thickness was 3 to 4 mm, and the kneaded product was cooled. Then, it grind | pulverized using the turbo mill (the turbo industry company make, "T-250 type"), and classified using the Alpine classifier. Next, an external additive having a blending amount (part by mass) shown in Table 1 was added, and a surface treatment was performed by using a Henschel mixer for 3 minutes at a rotational speed of 2500 rpm to obtain a magenta toner.
In addition, the compounding quantity of an external additive is the quantity when the sum total of components other than an external additive is 100 mass parts.

<Evaluation>
(Measurement of transmittance)
First, the sample was produced as follows using the heating and pressurizing apparatus 10 shown in FIG. The heating / pressurizing device 10 can be pressurized with a hydraulic pump, and includes a temperature / pressure control means 11, two supporting member sandwiching plates 12, and a gantry 13 that supports them. Further, the temperature / pressure control means 11 is provided with temperature measuring means (not shown).
The obtained magenta toner 5 to 8 mg was placed on a slide glass, and another slide glass was placed thereon to sandwich the toner, and this was placed on the slide glass support 14. As shown in FIG. 1, the slide glass support 14 was sandwiched between two support sandwiching plates 12 and attached to the heating / pressurizing device 10. Subsequently, the sample was heated by the temperature / pressure control means 11 at 100 ± 5 ° C. for 20 seconds, and a pressure of 4 MPa was applied to melt the toner to such an extent that the transparency could be confirmed.
The absorbance of the obtained sample was measured with a spectrophotometer (manufactured by Shimadzu Corporation, “UV-3100”). The transmittance was determined from the absorbance at a wavelength of 500 to 600 nm, and the smallest one was taken as the minimum transmittance. The results are shown in Table 2.

(Evaluation of component dispersibility)
Using the sample obtained by measuring the transmittance, the sample was observed with a transmission optical microscope (manufactured by Keyence Corporation, “Digital Microscope VHX-500”), and the degree of dispersion of the toner components was visually observed. The evaluation was made in four stages, ◎, ○, Δ, and ×. In addition, (double-circle) and (circle) were set as the pass. The results are shown in Table 2.

(Evaluation of color development: measurement of L value)
The obtained magenta toner and carrier (Powder Tech, “Ferrite Carrier”, average particle diameter: 50 μm) are mixed so that the toner concentration is 8% by mass, and mixed for 30 minutes using a ball mill. Thus, a developer was prepared.
Using the obtained developer, an image was printed by a page printer (“FS-C5020N” manufactured by Kyocera Mita Co., Ltd.). The L value of the image was measured with a spectrophotometer (manufactured by GretagMacbeth, “SpectroEye”, built-in filter: No, white base: Abs, light source: D50, observation field of view: 2 °, density standard: DIN). In addition, 40 or more was set as the pass. The results are shown in Table 2.

[Example 2]
A magenta toner was produced and evaluated in the same manner as in Example 1 except that the amount of magenta pigment added was changed to 6.5 parts by mass. The results are shown in Table 2.

[Example 3]
A magenta toner was produced and evaluated in the same manner as in Example 1 except that 3.0 parts by mass of an ester wax and 2.0 parts by mass of a polyethylene wax were used as a release agent. The results are shown in Table 2.

[Comparative Example 1]
A magenta toner was produced and evaluated in the same manner as in Example 1 except that 5.0 parts by mass of a polyethylene wax was used as a release agent. The results are shown in Table 2.

[Comparative Example 2]
A magenta toner was produced in the same manner as in Example 1 except that the addition amount of the magenta pigment was changed to 6.5 parts by mass and 5.0 parts by mass of a polypropylene wax was used as a release agent. Evaluation was performed. The results are shown in Table 2.

[Comparative Example 3]
Except for using 100 parts by mass of a styrene-acrylic resin as a binder resin, changing the addition amount of a magenta pigment to 6.5 parts by mass, and using 5.0 parts by mass of a polypropylene wax as a release agent, In the same manner as in Example 1, a magenta toner was manufactured and evaluated. The results are shown in Table 2.

As is clear from Table 2, the magenta toner of the example having a minimum transmittance of 25% or less at a wavelength of 500 to 600 nm had good dispersibility of the toner component. Further, developers using these were excellent in color development.
On the other hand, the magenta toner of the comparative example in which the minimum transmittance at a wavelength of 500 to 600 nm exceeded 25% was inferior in the dispersibility of the toner component as compared with the examples. In addition, the developers using these were inferior in color development to the examples.

  The toner of the present invention has good dispersibility of the toner component and excellent color developability. In addition, since the developer using the toner of the present invention can obtain a high-quality image, printing that requires high image quality, in particular, electrophotography, a copying machine using an electrostatic recording method, a printer, a fax machine, etc. Useful for.

It is a schematic sectional drawing which shows an example of the heating and pressurization apparatus used for the measurement of the transmittance | permeability.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Heating / pressurizing apparatus 11 Temperature / pressure control means 12 Support body clamping plate 13 Base 14 Slide glass support body

Claims (3)

  A toner comprising a binder resin and a magenta pigment and having a minimum transmittance of 25% or less at a wavelength of 500 to 600 nm.   The toner according to claim 1, comprising an ester-based wax.   The toner according to claim 1, wherein the softening point is 95 to 120 ° C.

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