JP2008139464A - Electrophotographic glossy toner and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrophotographic glossy toner having a massive feeling peculiar to a metal as well as a gloss and a method for manufacturing the same. <P>SOLUTION: The electrophotographic glossy toner is obtained by dispersing, in a binder resin, a coloring component composed essentially of yellow, magenta and cyan colorants and a pearl pigment formed by covering a flaky inorganic crystal substrate with the thin layer of titanium dioxide. The method for manufacturing the electrophotographic glossy toner comprises a first step of melt-kneading at least a binder resin and yellow, magenta and cyan colorants and then carrying out pulverization and classification to prepare toner base particles, and a second step of melt-kneading at least the toner base particles and the pearl pigment formed by covering the flaky inorganic crystal substrate with the thin layer of titanium dioxide and then carrying out pulverization and classification. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a glossy toner for electrophotography and a method for producing the same.

In electrophotography, a charge image formed on the surface of a photoreceptor is developed with toner to form a toner image, the toner image is transferred onto a transfer paper, and the transferred toner image is fixed to form an image.
As the electrophotographic toner used for this purpose, a black toner and a color toner are known.
On the other hand, in a field where decorativeness is required, for example, an electrophotographic copy or printed matter of gold or silver may be required.
For gold, a toner using a special pearl pigment is known (for example, see Patent Document 1).
However, although this toner has gloss, it lacks the weight feeling peculiar to metals, and further improvement has been desired.

JP-A-62-100770

  The present invention has been made in view of the above-described problems, and the object of the present invention is glossy toner for electrophotography (hereinafter referred to as glossy toner) having glossiness and metal-specific weight. It is in providing the manufacturing method.

The present invention has solved the above problems by the following technical configuration.
(1) a coloring component comprising at least a coloring agent comprising yellow, magenta and cyan (hereinafter referred to as a coloring agent) and a pearl pigment in which a thin layer of titanium dioxide is coated on a flaky inorganic crystal substrate; A glossy toner for electrophotography characterized by being dispersed in a binder resin.
(2) The glossy toner for electrophotography as described in (1) above, wherein the colorant comprising yellow, magenta and cyan is contained in the toner in an amount of 1 to 10% by weight.
(3) The colorant consisting of yellow, magenta and cyan, wherein the colorant corresponding to the minimum content is contained in the toner in an amount of 0.005 to 0.05% by weight. Glossy toner for electrophotography.
(4) The ratio of yellow in the colorant composed of yellow, magenta and cyan is 85 to 98% by weight in the total colorant, and the ratio of cyan is 0.1 to 1% by weight. The glossy toner for electrophotography according to (2) above.
(5) The ratio of magenta in the colorant composed of yellow, magenta and cyan is 25 to 40% by weight in the total colorant, the ratio of cyan is 0.1 to 1% by weight, and exhibits a copper color. The glossy toner for electrophotography as described in (2) above,
(6) The glossy toner for electrophotography according to (1), wherein the pearl pigment is contained in the toner in an amount of 1 to 30% by weight.
(7) The glossy toner for electrophotography according to (1), wherein the binder resin is a polyester resin.
(8) a first step of producing toner base particles by melt-kneading and pulverizing at least a binder resin and a colorant composed of yellow, magenta and cyan, and at least the toner base particles and the flaky inorganic crystal substrate; A method for producing a glossy toner for electrophotography, comprising: a second step of melt kneading and pulverizing and classifying a pearl pigment coated with a thin layer of titanium dioxide.

  ADVANTAGE OF THE INVENTION According to this invention, the glossy toner provided with the glossiness peculiar to a metal with glossiness and its manufacturing method can be provided.

  Hereinafter, materials constituting the toner of the present invention will be described in detail.

[Coloring ingredients]
The glossy toner of the present invention is characterized in that the coloring component is at least composed of a colorant composed of yellow, magenta and cyan and a specific pearl pigment.
<Colorant>
The colorant is not particularly limited as long as it is usually used for toner, and aniline blue, calco oil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green. There are oxalate, rose bengal, Hansa Yellow G rhodamine 6C lake, quinacridone and the like.
As the colorant, it is necessary to contain all of yellow, magenta and cyan colorants.
The colorant needs to be contained in a sufficient proportion to form a visible image having a sufficient concentration. For example, the colorant is preferably contained in the toner particles in a proportion of about 1 to 10% by weight.
Of the colorants composed of yellow, magenta and cyan, it is preferable that 0.005 to 0.05% by weight of the colorant corresponding to the minimum content is contained in the toner. By containing a slight amount of conflicting colors (for example, cyan for yellow and magenta), moderate turbidity is imparted, and the weight of the metal can be given together with the pearl pigment.
When the least amount of yellow, magenta, and cyan is less than 0.005% by weight, the toner image cannot give a sense of weight, and when it exceeds 0.05% by weight, the decorativeness as a glossy toner is lacking. Therefore, it is not preferable.
In order to change the color of the glossy toner of the present invention to gold, the ratio of yellow in the colorant is 85 to 98% by weight in the total colorant, and the ratio of cyan is 0.1 to 1% by weight. Further, in order to make the color of the glossy toner copper, the magenta ratio in the colorant is 25 to 40% by weight in the total colorant, and the cyan ratio is 0.1 to 1% by weight. It is preferable to do.

<Pearl pigment>
A pearl pigment refers to a pigment obtained by coating a thin layer of titanium dioxide on a flaky inorganic crystal substrate.
As a flaky inorganic crystal substrate, mica (mica) is the best in terms of aspect ratio, but any flaky inorganic crystal can be used, for example, barium sulfate, layered silicate, layered aluminosilicate, etc. Can be used. In general, the aspect ratio (ratio of thickness to length) of the substrate is desirably in the range of about 1:10 to 1:50.
The amount of titanium dioxide deposited on the flaky inorganic crystal substrate is determined by the degree of the metallic click gloss, but may be in the range of 10 to 60% by weight, particularly 15 to 50% by weight of titanium dioxide per pigment. desirable.
The titanium dioxide thin film is formed by a method known per se, for example, by gradually hydrolyzing a solution of a soluble titanium compound in a slurry containing a flaky inorganic crystal substrate, and gradually converting the titanium dioxide into a flaky inorganic crystal substrate. It can manufacture by making it deposit.
The pearl pigment used in the present invention preferably has an average particle diameter of 1 to 40 μm, particularly 1 to 20 μm. That is, when the particle size is smaller than 1 μm, the metallic gloss tends to be lost, whereas when it is larger than 40 μm, it is difficult to uniformly disperse the toner.
In the glossy toner of the present invention, the pearl pigment is preferably 1 to 30% by weight, more preferably 5 to 15% by weight in the toner. That is, when the pearl pigment is less than 1% by weight, it is difficult to sufficiently develop a metallic luster, and when it exceeds 30% by weight, the fixing property is lowered or economically disadvantageous. Tend.
In the glossy toner of the present invention, other white pigments or transparent fillers can be used in combination as a coloring component, whereby the color tone can be adjusted.

[Binder resin]
As the binder resin to be blended in the glossy toner of the present invention, styrene resin, acrylate ester resin, styrene-acrylate copolymer resin, styrene-methacrylate copolymer resin, polyvinyl chloride, polyacetic acid Vinyl, polyvinylidene chloride, phenol resin, epoxy resin, polyester resin, hydrogenated rosin, olefin resin, cycloolefin copolymer resin, cyclized rubber, polylactic acid resin, terpene phenol resin, etc. Can be used as a mixture. Among these, polyester resins that can obtain stronger gloss and smooth color development are preferable.
The content of the binder resin is preferably 50 to 95% by weight in the toner.

[Other ingredients]
The glossy toner of the present invention may be blended with other compounding agents such as a charge control agent and a release agent that do not adversely affect the color of the toner and can be regarded as colorless, white, or substantially colorless.
As the charge control agent, for the purpose of positive charge control, organic compounds having a basic nitrogen atom, for example, basic dyes, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes or fillers surface-treated therewith. As the negative charge control agent, a carboxy group-containing compound such as an alkyl salicylic acid metal chelate is used.
These charge control agents are preferably used in an amount of 1 to 10% by weight in the toner.

  As the release agent, release agents such as silicone oil low molecular weight olefin resins, carnauba wax and various waxes can be used in an amount of 2 to 15% by weight in the toner.

Then, it is preferable that an external additive such as a flow modifier is attached to the surface of the glossy toner of the present invention as necessary. The external additive is attached by mixing the glossy toner and the external additive using a Henschel mixer, a super mixer, or the like.
Examples of the flow modifier include silica, alumina, ceria, germania, titania, zirconia, and mixtures thereof. Of these, silica, alumina, and titania are preferable, and silica is particularly preferable.
The mixing amount of the flow modifier is preferably 0.3 to 3.0 parts by weight, more preferably 0.3 to 2.0 parts by weight, and more preferably 0.4 to 1. More preferably, it is 5 parts by weight. If it is less than 0.3% by weight, the image density is low from the beginning, and if continuous copying is continued, it is difficult to maintain the image density. If it exceeds 3.0% by weight, problems such as non-uniform toner layer thickness on the sleeve and contamination of the photoreceptor occur.
Further, the glossy toner of the present invention may be provided with inorganic fine particles, magnetic powder, talc, clay, calcium carbonate, magnesium carbonate, zinc oxide, silicon carbide for the control of chargeability, cleaning properties, storage stability, and the like as necessary. External additives other than flow modifiers such as fatty acid metal salts such as magnesium stearate and zinc sutearate and various resin fine particles may be attached.

  The volume average particle diameter (50% diameter measured by Coulter Multisizer II) of the glossy toner of the present invention is preferably 5 to 12 μm, and more preferably 6 to 10 μm. When the volume average particle size is less than 5 μm, it contains a lot of ultrafine powder of 5 μm or less, fogging, image density reduction, black spots and filming on the photoconductor, and fusion on the developing sleeve and layer thickness regulating blade. Cause, etc. On the other hand, if it exceeds 12 μm, the resolution is lowered and a high-quality image cannot be obtained.

Next, a method for producing the glossy toner of the present invention will be described.
When the glossy toner of the present invention is produced by simultaneously melt-kneading and pulverizing and classifying a colorant, a pearl pigment and a binder resin, it is difficult to uniformly disperse the pearl pigment having a large average particle diameter in the binder resin.
Therefore, in the present invention, (1) a first step of blending a binder resin and a colorant together with other compounding agents as necessary, uniformly melting and kneading them, and pulverizing and classifying them to obtain toner base particles;
(2) A production method comprising the second step of blending the toner base particles and the pearl pigment together with other compounding agents as required, uniformly melting and kneading them, and pulverizing and classifying them is adopted.
In addition to the above steps, a third step of mixing an external additive such as a flow modifier as described above may be provided.
Further, the binder resin and the colorant are blended with other compounding agents as necessary, and are melt-kneaded and pulverized to form toner base particles (a). The binder resin and the pearl pigment are combined with other compounding agents as necessary. They may be blended, melt-kneaded and pulverized to form silver toner base particles (b), and these (a) and (b) may be dry-mixed with a super mixer, a Henschel mixer, or the like to obtain a glossy toner. However, the above-described method is excellent in terms of toner gloss and weight.
Furthermore, as another production method, the binder resin is dissolved in a solvent such as toluene and xylene, the pearl pigment is dispersed in the presence of a colorant, and the resulting stock solution is spray-dried and granulated, whereby spherical particles are obtained. A glossy toner in the form of can be obtained. This method can be said to be an excellent method in that the pearl pigment is not destroyed.
Further, the pearl pigment is dispersed together with a radical initiator in a solvent that dissolves the binder resin monomer but does not dissolve the produced polymer, and the monomer is mixed in this system in the presence of the colorant. The glossy toner of the present invention can also be obtained by a polymerization method for polymerizing the toner.

The resulting glossy toner can be used as a one-component developer, or can be mixed with a carrier and used as a two-component developer.
The carrier applied to the present invention is not particularly limited, but from the viewpoint of magnetic force, charging characteristics, shape, etc., for example, a ferrite carrier or a granulated magnetite carrier produced by a spray dry-granulation-firing process can be preferably used. .

  The glossy toner of the present invention is used not only for copying on ordinary white paper but also advantageously for use in forming an image on black paper or colored paper.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Example 1>
(First step)
・ 420 parts by weight of polyester resin (Made by Mitsubishi Rayon Co., Ltd., trade name: FC-1198)
Colorant (yellow) 174 parts by weight (manufactured by Clariant Japan, trade name: Hansa Yellow G Rhodamine 6C lake pigment)
Coloring agent (magenta) 5.4 parts by weight (manufactured by Dainichi Seika Co., Ltd., trade name: quinacridone pigment)
・ Coloring agent (cyan) 0.6 parts by weight (manufactured by Dainichi Seika Co., Ltd., trade name: phthalocyanine pigment)
The raw materials having the above blending ratio are mixed with a super mixer, hot melt kneaded with a twin-screw kneader, pulverized with a jet mill, and then classified with a dry air classifier, resulting in a volume average particle size (D50) of 9 0.0 μm of ocher toner base particles were obtained. The volume average particle diameter (D50) is a volume-based integrated 50% value by Coulter counter TA-II type.

(Second step)
Polyester resin 2556 parts by weight (Made by Mitsubishi Rayon Co., Ltd., trade name: FC-1198)
-284 parts by weight of pearl pigment (Nippon Koken Co., Ltd., trade name: Pearl Glaze MM-100R)
-280 parts by weight of carnauba wax (manufactured by Kato Yoko Co., Ltd., trade name: carnauba No. 2 powder)
・ 80 parts by weight of charge control agent (Orient Chemical Industries, trade name: Bontron S-34)
600 parts by weight of the toner base particles The above raw materials are dry-mixed for 20 minutes with a super mixer, melt-kneaded at 120 to 160 ° C. with a twin screw kneader (trade name: PCM-65), thickness 2 A plate-like melt-kneaded product of ˜3 mm was obtained. Next, the melt-kneaded product was pulverized with a jet mill and then classified with a dry air classifier to obtain a glossy toner having a volume average particle size of 9.0 μm. The volume average particle diameter (D50) is a volume-based integrated 50% value by Coulter counter TA-II type.

Next, with respect to 100 parts by weight of the glossy toner, the following external additives were mixed with a 300 L Henschel mixer at a rotation speed of 1220 rpm for 15 minutes to obtain the glossy toner (gold toner) of Example 1.
(Third step)
Silica 0.2 parts by weight (manufactured by Clariant Japan, average primary particle size 17.5 μm, specific surface area 140 m ² / g)
-Resin fine powder 0.3 parts by weight (manufactured by AUSIMINT, trade name: HYLAR461)
・ 0.5 parts by weight of titanium oxide (manufactured by Nippon Aerosil Co., Ltd., primary particle diameter 10 nm, BET specific surface area 65 ± 10, treating agent octylsilane)

<Example 2>
The first step is not performed, but in the second step, instead of 600 parts by weight of toner base particles, 174 parts by weight of colorant (yellow) (manufactured by Clariant Japan, trade name: Hansa Yellow G Rhodamine 6C lake pigment)
Coloring agent (magenta) 5.4 parts by weight (manufactured by Dainichi Seika Co., Ltd., trade name: quinacridone pigment)
・ Coloring agent (cyan) 0.6 parts by weight (manufactured by Dainichi Seika Co., Ltd., trade name: phthalocyanine pigment)
A glossy toner (gold toner) of Example 2 was obtained in the same manner as in Example 1 except that was used.

<Example 3>
A glossy toner (copper toner) of Example 3 was obtained in the same manner as in Example 1 except that the first step was as follows.
(First step)
・ 420 parts by weight of polyester resin (Made by Mitsubishi Rayon Co., Ltd., trade name: FC-1198)
Colorant (yellow) 120 parts by weight (manufactured by Clariant Japan, trade name: Hansa Yellow G Rhodamine 6C lake pigment)
・ Coloring agent (magenta) 59.4 parts by weight (manufactured by Dainichi Seika Co., Ltd., trade name: quinacridone pigment)
・ Coloring agent (cyan) 0.6 parts by weight (manufactured by Dainichi Seika Co., Ltd., trade name: phthalocyanine pigment)
The raw materials having the above blending ratio are mixed with a super mixer, hot melt kneaded with a twin-screw kneader, pulverized with a jet mill, and then classified with a dry air classifier, resulting in a volume average particle size (D50) of 9 0.0 μm red earth toner base particles were obtained. The volume average particle diameter (D50) is a volume-based integrated 50% value by Coulter counter TA-II type.

<Comparative Example 1>
The glossy toner (silver toner) of Comparative Example 1 in which no colorant was blended was obtained in the same manner as in Example 1 except that the first step was not performed and the toner base particles were not contained in the second step.

<Comparative example 2>
In the second step, a glossy toner (ocher toner) of Comparative Example 2 was obtained in the same manner as in Example 1 except that mica was used instead of the pearl pigment.

  Table 1 shows the main conditions of Examples and Comparative Examples.

  For the glossy toners of Examples and Comparative Examples, density unevenness, gloss, weight feeling, and color were measured.

<Evaluation method>
Under normal temperature and humidity (25 ° C./55% RH), a commercially available laser printer using a non-magnetic one-component toner (printing speed: 25 sheets / minute of A4 paper), a square solid of 1.0 cm × 1.0 cm on A4 paper. A continuous 3000 page copy test was performed under the condition that the pattern was printed at regular intervals of 15 lines in the main scanning direction and 11 lines in the sub-scanning direction, and density unevenness, gloss, and weight were evaluated.
Density unevenness: Measure all the reflection density of a solid corner in a page with a Macbeth reflection densitometer (RD-914). If the difference between the maximum value and the minimum value is less than 0.10, ◯, 0.10 or more and 0.0. If less than 25, Δ, and if 0.25 or more, ×.
Gloss: Gloss was confirmed visually, and it was rated as ◯ if it was fully equipped, △ if it was equipped, and x if it was insufficient.
A feeling of weight: The feeling of weight was confirmed by visual observation, and it was rated as “◯” if it was sufficiently equipped, “△” if it was equipped, and “x” if it was insufficient.
Color: The color was confirmed visually.
The results are shown in Table 2.

<Evaluation results>
The gloss toner images of Examples 1 and 3 were all good in density unevenness, gloss, and weight.
In the image using the glossy toner of Example 2, since the colorant is directly kneaded with the pearl pigment without passing through the first step, there is no problem in practical use. The feeling was slightly lacking.
On the other hand, in Comparative Example 1, since the colorant was not added, the weight feeling was insufficient.
In Comparative Example 2, the use of mica in place of the pearl pigment did not provide sufficient gloss, and the overall color was ocher rather than gold. Moreover, the weight feeling was insufficient.

Claims (8)

  A coloring component comprising at least a pearl pigment in which a thin layer of titanium dioxide is coated on a flaky inorganic crystal substrate and a coloring agent comprising yellow, magenta and cyan is dispersed in a binder resin. Glossy toner for electrophotography.   2. The glossy toner for electrophotography according to claim 1, wherein the toner contains 1 to 10% by weight of a colorant comprising yellow, magenta and cyan.   3. The gloss for electrophotography according to claim 2, wherein a colorant corresponding to the minimum content among the colorants composed of yellow, magenta and cyan is contained in the toner in an amount of 0.005 to 0.05% by weight. toner.   The ratio of yellow in the colorant composed of yellow, magenta and cyan is 85 to 98% by weight in the total colorant, and the ratio of cyan is 0.1 to 1% by weight. Item 3. The glossy toner for electrophotography according to Item 2.   The magenta ratio in the colorant composed of yellow, magenta and cyan is 25 to 40% by weight in the total colorant, the cyan ratio is 0.1 to 1% by weight, and exhibits a copper color. The glossy toner for electrophotography according to claim 2. 2. The glossy toner for electrophotography according to claim 1, wherein the pearl pigment is contained in an amount of 1 to 30% by weight in the toner.   2. The glossy toner for electrophotography according to claim 1, wherein the binder resin is a polyester resin. A first step of producing toner base particles by melt-kneading and pulverizing at least a binder resin and a colorant comprising yellow, magenta and cyan; and
A gloss toner for electrophotography comprising: a second step of melt-kneading and pulverizing at least the toner base particles and a pearl pigment in which a thin layer of titanium dioxide is coated on a flaky inorganic crystal substrate. Manufacturing method.