JP2003149870A - Electrophotographic color toner, toner cartridge, and image forming apparatus - Google Patents

Abstract

The present invention relates to a color toner for electrophotography, a toner cartridge, and an image forming apparatus, which provide a color toner capable of stably developing an image having a vivid color tone, and an image forming apparatus using the same. I do. SOLUTION: While mixing at least two kinds of toners selected from three or more kinds of color toners and black toners having different hues at least composed of a binder resin and a colorant, mixing two or more kinds of selected color toners A surface modifier different in type and / or composition is attached to the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for electrophotography, a toner cartridge, and an image forming apparatus, and more particularly, two or more kinds selected from yellow, magenta, cyan, and black toners. The present invention relates to a color toner for electrophotography, a toner cartridge, and an image forming apparatus which are characterized by a configuration for stabilizing the developability of a color toner obtained by mixing toners.

[0002]

2. Description of the Related Art The electrophotographic method is a technology widely used in image forming apparatuses such as copying machines, electrophotographic facsimiles, and electrophotographic printers. As the electrophotographic method, for example, US Pat. No. 2,297,691 is cited. As described, photoconductive insulator-based schemes are commonly used.

In this method, a photoconductive insulator charged by a corona discharge or a charge supply roller is irradiated with light from a laser, an LED, or the like to form an electrostatic latent image, which is called a toner. A resin powder colored with a pigment or a dye is electrostatically adhered to the electrostatic latent image to develop it to form a visualized toner image, which is then transferred onto a recording medium such as paper or film. It is transcribed.

However, since the toner image at this time is a powder image which is simply placed on the recording medium, it is necessary to fix the toner image on the recording medium. Therefore, in the final step, the toner is fused on the recording medium by heat, pressure, light or the like and then solidified to finally obtain a toner image fixed on the recording medium.

As described above, the fixing of the toner means that the toner, which is a powder containing a thermoplastic resin (hereinafter referred to as a binder resin) as a main component, is melted by heat and fixed on the recording medium. Well-known methods include a heat roll method in which a recording medium on which a toner image is formed is directly heated and pressed by a roller, and a flash fixing method in which toner is fixed on the recording medium by flash light irradiation such as a xenon flash lamp. There is.

In order to obtain a color image, three color toners of yellow toner, magenta toner, and cyan toner, or four color toners of black toner in addition to the three color toners are developed and superposed. Printing method for performing color printing according to Japanese Patent Laid-Open No. 61-13
As described in Japanese Patent No. 2959, there is known a printing method for performing color printing by superposing two colors or two or more colors of black toner or color toner.

In the former printing method, color toners of yellow toner, magenta toner, cyan toner, and black toner are set in a yellow developing device, a magenta developing device, a cyan developing device, and a black developing device, respectively. Is formed. In this case, even if the physical properties of the respective color toners are different, it is possible to make the developing characteristics the same by optimizing the developing conditions, but on the other hand, the device structure becomes complicated and the high cost device is used. Becomes

On the other hand, in the latter printing method, if at least one developing device for developing color toner is used, color printing can be performed, the structure of the device is simple, and the device is low cost.

In the latter printing method, Japanese Patent Laid-Open No.
As described in Japanese Patent Laid-Open No. 348101, there is known a printing apparatus having a fluidized bed for uniformly mixing toners having substantially the same physical properties and different colors at a set ratio. In addition, JP-A-11-32719
As described in Japanese Patent Laid-Open No. 2 (1994), a method of adding a conductive additive to the toner is known as a method of controlling the electric resistance of the toner.

Further, conventionally, the chargeability of color toners is positively or negatively charged by adding a charge control agent, and the surface of a magnetic carrier to be combined with such toners is coated with resin or the like. As a result, the charge polarity and charge amount are controlled.

[0011]

However, when a printed image is obtained by using a color toner obtained by mixing two or more kinds of toner selected from yellow toner, magenta toner, cyan toner and black toner, There is a problem that the color tone of the printed image becomes unstable.

That is, yellow toner, magenta toner,
A yellow pigment, a magenta pigment, a cyan pigment, which are used as colorants for cyan toner and black toner, respectively.
Since the charging properties of carbon black are greatly different, yellow toner, magenta toner, cyan toner and black toner having different charging properties can be obtained.

This is because when the color toners obtained by combining and mixing the color toners having different charging properties are printed, the combined color toners are unevenly developed.

Therefore, yellow pigments having different charging properties,
There is a need for a method for precisely adjusting the chargeability of yellow toner, magenta toner, cyan toner, and black toner containing magenta pigment, cyan pigment, and carbon black, respectively.

Therefore, an object of the present invention is to provide a color toner capable of stably developing an image having a vivid color tone, an image forming apparatus using the color toner, and the like.

[0016]

Means for solving the problems of the present invention will now be described, but for easier understanding, reference is made to FIG. In order to achieve the above-mentioned object, in the present invention, the electrophotographic color toner is selected from three or more kinds of color toners and black toners having different hues each including at least a binder resin and a colorant. It is a color toner obtained by mixing toners of different types, and is characterized in that surface modifiers of different types and / or compositions are attached to the surfaces of two or more types of color toners.

As described above, by attaching surface modifiers of different types and / or compositions to the surfaces of two or more types of color toners, even when color colorants having different charging characteristics are used, the toner particles as a whole are In this case, the charge amount per unit weight can be made substantially equal, whereby the combined color toners can be uniformly developed, and an image having a vivid color tone can be stably developed. In addition,
FIG. 1 is a diagram showing the concentration distribution of the surface modifier in the toner when the two types of toner are mixed, and the titanium oxide and the SiO in the two types of toner are divided into two groups of dots. It shows that the composition ratio of the surface modifier composed of ₂ is different.

In this case, among the two or more types of color toners, the color toner having the maximum charge amount per unit weight and the color toner having the minimum charge amount per unit weight have the same charge amount per unit weight. The ratio of the difference to the charge amount per unit weight of the color toner having the minimum charge amount per unit weight is preferably 20% or less, more preferably 15% or less. The maximum and minimum in this case mean absolute values.

As described above, by suppressing the difference between the charge amounts to 20% or less, the combined color toners can be uniformly developed, and the change rate of the toner specific charge with time due to image formation can be reduced. As a result, the combined toner is uniformly consumed, so that it is possible to stably develop an image having a vivid color tone for a long period of time.

Various combinations of three or more color toners having different hues are possible, but yellow toner, magenta toner and cyan toner are typically desirable.

The amount of the surface modifier added is preferably 0.1 to 5 parts by weight, and more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of each color toner. When the content exceeds the weight%, the color saturation of the toner decreases, and the image quality deteriorates.

Examples of such surface modifiers include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, silica ash. Inorganic fine particles selected from stone, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride are preferable. As such a surface modifier, it is preferable to use one whose surface has been subjected to a hydrophobic treatment. The surface modifier may be surface-treated with only one kind of the above-mentioned inorganic compound fine particles, or may be a combination of two or more kinds.

Further, by using the above electrophotographic toner, it is possible to realize an image forming apparatus capable of stably developing an image having a vivid color tone.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Now, a preferred procedure of the embodiment of the present invention will be described. The color toner of the present invention can be manufactured by a conventionally known manufacturing method, and at least a binder resin, a colorant, and if necessary, a charge control agent and wax are added to be a raw material. This raw material is kneaded by, for example, a pressure kneader, a roll mill, an extruder or the like, and uniformly dispersed. After that, for example, pulverize with a crusher, jet mill, etc. to make fine powder, and classify with an air classifier, etc.
A toner having a desired particle size distribution is obtained.

Then, in order to adjust the charging property of the obtained toner, the toner is attached to the surface of the toner with a surface modifier.
In order to attach the surface modifier to the toner surface, it may be mixed with a Henschel mixer or the like.

Next, two or more kinds of toners selected from the yellow toner, magenta toner, cyan toner, and black toner obtained by the above method are appropriately mixed according to the color tone to be obtained, and for example, Henschel. By uniformly mixing with a mixer or the like, the electrophotographic color toner of the present invention can be obtained.

In each color toner in this case, when the total amount of the toner is 100 parts by weight, for example, the binder resin is 75 to
It is desirable that the amount of the coloring agent is 95 parts by weight and the colorant is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight.

The binder resin used in the present invention is not particularly limited, and thermoplastic resins made of various natural or synthetic polymer substances can be used. For example, epoxy resin, styrene-acrylic resin, polyamide resin. , A polyester resin, a polyvinyl resin, a polyurethane resin, a polybutadiene resin and the like, which are used alone or in combination.

The colorant contained in the color toner of the present invention is not particularly limited, and known colorants can be used. For example, a monoazo red pigment, a disazo yellow pigment, a quinacridone magenta pigment, an anthraquinone dye, a nigrosine dye, a quaternary ammonium salt, a monoazo metal complex salt dye, or the like can be used. May be.

More specifically, as such a coloring agent, for example, aniline blue (CI. No. 50405),
Calco Oil Blue (CI No. azoic Bl
ue3), chrome yellow (C.I. No. 1409)
0), Ultramarine Blue (C.I. No. 7710)
3), DuPont Oil Red (C.I. No. 2610)
5), quinoline yellow (C.I. No. 47005)
, Methylene blue chloride (C.I. No. 520
15), phthalocyanine blue (C.I. No. 741)
60), malachite green oxalate (C.I.N.
o. 42000), Edible Red No. 2 (Amaranth, C.I.
I. No. 16185), Edible Red No. 3 (Erythrosin, CI No. 45430), Edible Red No. 40 (Arla Red AC, CI No. 16035), Edible Red No. 102 (New Coxine, CI No. .1625
5), Edible Red No. 104 (Ploxine, CI No.
45410), Edible Red No. 105 (Rose Bengal,
C. I. No. 45440), food red No. 106 (acid red, CI No. 45100), <yellow> food yellow No. 4 (tartrazine, CI No. 1914).
0), Edible Yellow No. 5 (Sunset Yellow FCF, C.I.
I. No. 15985), <Green> Edible Green No. 3 (Fast Green FCF, CI No. 42053),
<Blue> Edible Blue No. 1 (Brilliant Blue FCF,
C. I. No. 42090), Food Blue No. 2 (Indigo Carmine, CI No. 73015) and the like can be used.

The surface modifier that can be used here has a particle size of 5 nm to 2 μm, preferably 5 nm to 50 μm.
Preferably the particles in the range of 0 nm, also, it is preferable that the specific surface area by the BET method is 20m ² / g~500m ² / g.

The amount of the surface modifier added to the color toner of the present invention may be adjusted depending on the chargeability and the amount of addition of the yellow pigment, magenta pigment, cyan pigment and carbon black used as the colorant of the toner. , Toner 10
It is 0.1 to 5 parts by weight, preferably 0.1 to 2.0 parts by weight, relative to 0 parts by weight.

Examples of such surface modifiers include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite. Fine particles of diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like can be used. Among these, it is particularly preferable to use silica fine particles and / or titanium oxide fine particles. The surface modifier may be surface-treated with only one kind of the above-mentioned inorganic compound fine particles, or may be a combination of two or more kinds.

As such fine particles of an inorganic compound, fine particles of silicon dioxide (silica) as a silicon oxide compound can be used. For example, R972, R974, R976, R can be used.
Y50, NY50, RY200, RY200S, RX5
0, NAX50, RX200, RX300, NA50
H, RA200H, RA200HS, REA200 (above, trade name manufactured by AEROSIL), TG-308F, T
G-709F, TG-810G, TG-811F, TG
-820F, TS-530, TS-610, TS-72
0, TS-500 (above, trade name manufactured by CABOT), H
2015EP, H2050EP, H2150VP, H3
050VP, H1018, H1303VP, H2000
/ 4, H2000 / 4M, H2000, H3004, H
15, H20, H30, HVK2150, HVK211
5 (above, trade name of Clariant Co., Ltd.) can be used.

In the case of a titanium oxide compound, for example, T
TO-55 (C), TTO-55 (S), ET-300
W, SN-100P, FT-1000, FT-200
0, FT-3000 (above, trade name of Ishihara Sangyo Co., Ltd.), S
TT-30A, STT-65C-S, STT-65C
(These are trade names of Titanium Industry Co., Ltd.).

In the case of tin oxide compounds, for example, EC-
300 (trade name, manufactured by Titanium Industry Co., Ltd.) can be used. In the case of a zinc oxide compound, for example, ZnO-31
0, ZnO-305, and ZnO-350 (trade name of Sumitomo Osaka Cement Co., Ltd.) can be used. Further, in the aluminum oxide compound, for example, Al203C (AE
For example, a trade name manufactured by ROSIL) can be used.

The inorganic compound fine particles used as the surface modifier are preferably those whose surface is subjected to a hydrophobic treatment. For example, the surface of the inorganic compound fine particles is treated with a silane coupling agent, silicone oil or the like. It may be chemically surface-treated.

As such a surface treating agent, known agents such as dimethyldichlorosilane, dimethylpolysiloxane, hexamethyldisiloxane, aminosilane and alcohol can be used. Furthermore, in order to control the charge of the toner, a surface modifier coated with an amine compound or the like may be used.

Furthermore, a charge control agent may be added to the color toner of the present invention for the purpose of imparting chargeability and reducing a change in charge amount under different temperature and humidity environments. The charge control agent is colorless. To light-colored ones are preferred.

As such a charge control agent, for example, 4
Well-known positively and negatively chargeable charge control agents such as a quaternary ammonium salt compound, a salicylic acid compound, a boron complex, and a carboxylic acid compound can be used.

Next, a printing test is carried out to measure the charge amount of the color toner produced by the above procedure and materials. First, the charge amount of color toner is measured by a blow-off charge amount measuring device (TB-2
00; trade name, manufactured by Toshiba Chemical Co., Ltd.).

Next, the process speed of the image forming apparatus is 1
A high-speed development type color laser printer of 100 mm / s, for example, F6708B (Fujitsu brand name: 50 sheets / minute), 50 sheets / minute) is used to print, for example, 100,000 sheets or more, Assess stability.

Here, the conceptual configuration of the used color laser printer will be described with reference to FIG. See FIG. 2. FIG. 2 is a conceptual configuration diagram of the color laser printer used in the print test. The photoconductor 1 made of amorphous silicon.
0 around the charger 20, the exposing means 30, the developing means 4
0, a transfer device 50, a cleaner 60, a static eliminator 70, a flash fixing device 80 having a xenon flash lamp 81, and the like.

The developing means 40 includes a developer container 41, a developing roller 43, and a stirring blade (not shown), and brings the toner particles TO and the carrier particles CA in the developer container 41 into contact with each other to impart a predetermined charge amount to the toner. It is supposed to be done. Further, the color toner of the present invention is set in advance in the toner hopper 45, and when the toner concentration in the developing container decreases due to printing, the color toner is supplied from the toner hopper 45 to the developing container 41.

On the premise of the above matters,
Specific examples of the present invention will be described, but comparative examples will also be described to clarify the effects of the examples of the present invention. (Example 1) First, in order to produce a yellow toner, a binder resin: a polyester resin (manufactured by Kao) 88 parts by weight Colorant: a yellow pigment (Toner Yellow HG; a product name of Clariant) 5 parts by weight Negative charge control agent : E-89 (trade name, manufactured by Orient Chemical Co., Ltd.) 2 parts by weight or more of materials are put into a Henschel mixer, premixed, kneaded by an extruder, then roughly crushed by a hammer mill, and further jetted. Finely pulverized with a mill and classified with an air stream classifier to obtain a volume average particle size of about 8.
5 μm yellow toner is obtained.

Next, a cyan toner is prepared by the same process as that of the yellow toner except that 5 parts by weight of a cyan pigment (Lionol Blue ES; trade name of Toyo Ink) is added as a colorant instead of the yellow pigment.

Next, in order to modify the surface of the yellow toner, the yellow toner 100 manufactured in the above process is used.
0.3 parts by weight of hydrophobic silica (H2000 / 4; trade name manufactured by Clariant Co., Ltd.) and 0.7 parts by weight of titanium oxide (STT30A; trade name manufactured by Titanium Industry Co., Ltd.) were added to parts by weight, and a Henschel mixer was used. And stir to deposit hydrophobic silica and titanium oxide on the surface.

Yellow toner 5 thus surface-modified
The charge amount as a two-component developer obtained by mixing 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as described above and found to be -17.1 μC / g. Met.

Next, in order to modify the surface of the cyan toner, 0.7 part by weight of hydrophobic silica (H2000 / 4; trade name of Clariant) is added to 100 parts by weight of the cyan toner produced in the above process. Part titanium oxide (STT30A; trade name of Titanium Industry Co., Ltd.) 0.3 part by weight is added and stirred using a Henschel mixer to deposit hydrophobic silica and titanium oxide on the surface.

The charge amount as a two-component developer obtained by mixing 5 parts by weight of the thus surface-modified cyan toner and 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was used. When measured as described above, it was -17.3 μC / g.

Next, the yellow toner and the cyan toner surface-modified as described above are mixed using a Henschel mixer at a ratio of 50 parts by weight of the surface-modified yellow toner and 50 parts by weight of the surface-modified cyan toner. Then, a green color toner was obtained.

Using this two-component developer consisting of green toner and carrier, a print test of 10 sheets was conducted using the above-mentioned color laser printer, and the toner specific charge, the density of the printed image, and the saturation were investigated. did. The two-component developer used here was a mixture of 5 parts by weight of the color toner manufactured in the above-mentioned step and 95 parts by weight of a silicone resin coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) in a ball mill.

Next, for this green toner, a particle analyzer (PT1000; trade name by Yokogawa Electric Corporation)
Is used to determine the concentration distribution of the surface modifier of the toner.
It was measured according to the method described in JP-A 1-34006.

Referring again to FIG. 1, FIG. 1 is a diagram showing the measurement results of the concentration distribution of the surface modifier of the toner. Since the corresponding plots of each toner particle are divided into two groups, titanium oxide is used. It is apparent that the toner is composed of a toner (yellow toner) having a relatively high concentration of hydrophobic silica as compared with the concentration and a toner (cyan toner) having a relatively high concentration of titanium oxide as compared with the concentration of hydrophobic silica. . Note that Ti and Si in the figure
Are shown as the weight of TiO ₂ and SiO ₂ , respectively.

When 100,000 sheets were printed using this green toner, the variation ratio of the toner specific charge was within 20%, and it was confirmed that an image having a vivid color tone can be stably printed.

(Example 2) As individual color toners to be used, a cyan toner produced in the same manner as in Example 1 above and a magenta pigment (Toner Magenta EB; trade name of Clariant) instead of a yellow pigment as a colorant. Magenta toner obtained by the same process as the above yellow toner is used except that 5 parts by weight of is added.

To 100 parts by weight of this magenta toner, 1.0 part by weight of titanium oxide (STT30A; trade name, manufactured by Titanium Industry Co., Ltd.) was added and stirred using a Henschel mixer to deposit titanium oxide on the surface.

Magenta toner 5 surface-modified in this way
The charge amount as a two-component developer obtained by mixing 95 parts by weight with a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as described above and found to be -16.8 μC / g. Met.

On the other hand, with respect to the cyan toner, to 100 parts by weight of the cyan toner, 0.5 parts by weight of hydrophobic silica (H2000 / 4; trade name manufactured by Clariant Co., Ltd.) titanium oxide (STT30A; trade name manufactured by Titanium Industry Co., Ltd.) Add 0.5 parts by weight and stir with a Henschel mixer to deposit hydrophobic silica and titanium oxide on the surface.

The charge amount as a two-component developer obtained by mixing 5 parts by weight of the thus surface-modified cyan toner and 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo) in a ball mill was used. When measured as described above, it was -16.2 μC / g.

Next, the surface-modified magenta toner and cyan toner as described above are mixed using a Henschel mixer in a ratio of 80 parts by weight of surface-modified magenta toner and 20 parts by weight of surface-modified cyan toner. Thus, a magenta color toner was obtained.

5 parts by weight of this reddish-purple toner and silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo) 9
Using a two-component developer prepared by mixing 5 parts by weight with a ball mill, a printing test of 10 sheets was conducted using the above-mentioned color laser printer, and the toner specific charge, the density of the printed image, and
I investigated the saturation.

When 100,000 sheets were printed using this red-purple toner, the variation rate of the toner specific charge was within 20% in this case as well, and it was confirmed that an image with a vivid color tone can be stably printed.

(Example 3) As individual color toners to be used, a yellow toner produced in the same manner as in Example 1 above, a magenta toner produced in the same manner as in Example 2 above, and a yellow pigment as a colorant. A black toner prepared by the same process as the above yellow toner is used except that 10 parts by weight of carbon black (Mogar L; trade name manufactured by CABOT Co.) is added instead of.

Also in this case, exactly the same as in the first embodiment,
To 100 parts by weight of the yellow toner, 0.3 parts by weight of hydrophobic silica (H2000 / 4; trade name manufactured by Clariant Co., Ltd.) and 0.7 parts by weight of titanium oxide (STT30A; trade name manufactured by Titanium Industry Co., Ltd.) were added, and Henschel was added. Stir with a mixer to deposit hydrophobic silica and titanium oxide on the surface.

Further, in the same manner as in Example 2 above, for magenta toner, 1.0 part by weight of titanium oxide (STT30A; trade name of Titanium Industry Co., Ltd.) was added to 100 parts by weight of magenta toner. , Using a Henschel mixer, to deposit titanium oxide on the surface.

On the other hand, for the black toner, 1.0 part by weight of hydrophobic silica (H2000 / 4; trade name of Clariant Co., Ltd.) was added to 100 parts by weight of the black toner, and the mixture was stirred using a Henschel mixer. Adhere hydrophobic silica to the surface.

Black toner 5 surface-modified in this way
The charge amount as a two-component developer prepared by mixing 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as described above and found to be -17.2 μC / g. there were.

Then, the surface-modified yellow toner, magenta toner, and black toner as described above are surface-modified yellow toner 30 parts by weight. Surface-modified magenta toner 60 parts by weight. The black toner was mixed with a Henschel mixer at a ratio of 10 parts by weight to obtain a brick color toner.

5 parts by weight of this brick color toner and silicone resin coated magnetite carrier (manufactured by Kanto Denka Kogyo)
Using a two-component developer prepared by mixing 95 parts by weight with a ball mill, a printing test of 10 sheets was conducted using the above-mentioned color laser printer, and the toner specific charge, the density of the printed image, and
I investigated the saturation.

When 100,000 sheets were printed using this brick-color toner, the variation rate of the toner specific charge was within 20% in this case as well, and it was confirmed that an image with a vivid color tone can be stably printed.

Next, Comparative Examples 1 to 3 in which the same amount of the same surface modifier is added to all the color toners to be combined will be described. (Comparative Example 1) As the individual color toners used here, the yellow toner and the cyan toner which are exactly the same as those in the above-described embodiment are used. However, in this case, 1.0 part by weight of titanium oxide (STT30A; trade name of Titanium Industry Co., Ltd.) was added to 100 parts by weight of the yellow toner, and the mixture was stirred using a Henschel mixer to obtain titanium oxide on the surface. Attach it.

Yellow toner 5 surface-modified in this way
A charge amount as a two-component developer prepared by mixing 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as described above and found to be -13.3 μC / g. there were.

On the other hand, to 100 parts by weight of the cyan toner, as in the case of the yellow toner, 1.0 part by weight of titanium oxide (STT30A; trade name of Titanium Industry Co., Ltd.) was added and stirred using a Henschel mixer. Titanium oxide is attached to the surface.

The charge amount as a two-component developer prepared by mixing 5 parts by weight of the surface-modified cyan toner and 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill is as described above. Was -11.2 μC / g.

Next, the surface-modified yellow toner and the cyan toner as described above are mixed using a Henschel mixer at a ratio of 50 parts by weight of the surface-modified yellow toner and 50 parts by weight of the surface-modified cyan toner. Then, a blue-green color toner was obtained.

5 parts by weight of the blue-green toner and silicone resin-coated magnetite carrier (Kanto Denka Kogyo) 9
Using a two-component developer prepared by mixing 5 parts by weight in a ball mill, and using the color laser printer described above,
A printing test was performed on a sheet to examine the density and saturation of the printed image.

When printing was performed using this blue-green toner, a dark blue-green image was initially obtained, but the color tone gradually changed to green, and after printing 100,000 sheets, a yellow-green image was obtained. It becomes an image, and it is clear that the toner has low development stability and color tone stability.

It is considered that this is because the chargeability of the toner cannot be precisely controlled and the toners having different charge amounts are combined, and the consumption rate of the cyan toner having a small charge amount increases.

(Comparative Example 2) As the individual color toners to be used, the magenta toner and the cyan toner which are exactly the same as those in Example 2 are used. However, in this case, with respect to 100 parts by weight of the magenta toner, 0.5 part by weight of hydrophobic silica (H2000 / 4; product name of Clariant Co., Ltd.) titanium oxide (STT30A; product name of Titanium Industry Co., Ltd.) 0.5 Add parts by weight and stir with a Henschel mixer to deposit hydrophobic silica and titanium oxide on the surface.

Magenta toner 5 surface-modified in this way
The amount of charge as a two-component developer prepared by mixing by weight and 95 parts by weight of a silicone-based resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as described above and found to be -18.3 μC / g. there were.

On the other hand, with respect to the cyan toner, in the same manner as in Example 2 above, 0.5 part by weight of hydrophobic silica (H2000 / 4; trade name manufactured by Clariant) to 100 parts by weight of the cyan toner is used. (STT30A; trade name of Titanium Industry Co., Ltd.) 0.5 part by weight is added and stirred using a Henschel mixer to deposit hydrophobic silica and titanium oxide on the surface.

Then, the surface-modified magenta toner and the cyan toner were subjected to the same surface-modifying magenta toner in the same manner as in Example 2 (80 parts by weight) and the surface-modified cyan toner (20 parts by weight). Were mixed using a Henschel mixer at a ratio of 1 to obtain a purple color toner.

5 parts by weight of this purple toner and silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo) 95
Using a two-component developer in which parts by weight are mixed with a ball mill,
Using the above-mentioned color laser printer, a print test of 10 sheets was conducted to examine the density and saturation of the printed image.

When printing was carried out using this violet toner, a bluish violet image was initially obtained, but the color tone gradually shifted to reddish, and after printing 100,000 sheets, a violet image was obtained. It is clear that the toner has low development stability and color tone stability.

Also in the case of Comparative Example 2, the chargeability of the toner could not be precisely controlled, and the toners having different charge amounts were combined, and the consumption rate of the cyan toner having a small charge amount was high. Conceivable.

(Comparative Example 3) As the individual color toners to be used, the yellow toner, the magenta toner and the carbon black which are exactly the same as those in the above-mentioned Example 3 are used. In this case, however, 1.0 part by weight of hydrophobic silica (H2000 / 4; trade name of Clariant Co., Ltd.) was added to 100 parts by weight of the yellow toner, and the mixture was stirred using a Henschel mixer to make the surface hydrophobic. Adhere silica.

Yellow toner 5 surface-modified in this way
The amount of charge as a two-component developer prepared by mixing 95 parts by weight of a silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as above and found to be -23.5 μC / g. there were.

To 100 parts by weight of the magenta toner, 1.0 part by weight of hydrophobic silica (H2000 / 4; trade name of Clariant Co., Ltd.) was added, and the mixture was stirred using a Henschel mixer to make the surface hydrophobic. Deposit silica.

Magenta toner 5 surface-modified in this way
The amount of charge as a two-component developer prepared by mixing 95 parts by weight and silicone resin-coated magnetite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) with a ball mill was measured as described above and found to be −20.8 μC / g. there were.

On the other hand, to 100 parts by weight of the black toner, 1.0 part by weight of hydrophobic silica (H2000 / 4; trade name of Clariant Co.) was added in exactly the same manner as in Example 3, and a Henschel mixer was used. And stir to deposit hydrophobic silica on the surface.

Next, the yellow toner, the magenta toner, and the black toner, which have been surface-modified as described above, are added.
As in Example 3 above, surface-modified yellow toner 30 parts by weight surface-modified magenta toner 60 parts by weight surface-modified black toner 10 parts by weight were mixed using a Henschel mixer. A brick color toner was obtained.

5 parts by weight of this brick color toner and silicone resin coated magnetite carrier (manufactured by Kanto Denka Kogyo)
Using a two-component developer prepared by mixing 95 parts by weight with a ball mill, a printing test was performed on 10 sheets using the above-mentioned color laser printer, and the density and saturation of the printed image were investigated.

When printing was performed using this brick-color toner, a brick-color image was first obtained, but the blackness gradually decreased, the color tone changed to a vermilion color with a strong yellowish tint, and printing was continued. It is clear that the toner is overcharged, and after 100,000 sheets, the toner has a low vermilion color image due to a decrease in image density, and the toner has low development stability and color tone stability.

Also in Comparative Example 3, the chargeability of the toner could not be precisely controlled, and it is considered that this is because the toners having different charge amounts were combined, and the consumption rate of the black toner having a small charge amount was high. it is conceivable that.

[0096]

[Table 1]

[Table 2] Table 1 shows a summary of the composition ratios of the above color toners and black toners, and Table 2 shows the results of Examples 1 to 3 and Comparative Examples 1 to 3 described above. It is a compilation.

As is clear from Table 2, among the toners constituting the developers in Examples 1 to 3, the maximum charge amount of the toner and the minimum charge amount of the toner are determined. The ratio of the minimum charge amount to the charge amount of the toner is 1.2% to 3.7%, and since the chargeability and electric resistance of each toner are uniform, the mixed toner is consumed evenly.
The printed image is stable.

Further, it can be confirmed that an image having a vivid color tone can be stably printed by using the color toner of the present invention, and the yellow toner, magenta toner,
It was clarified that various colors such as green, vermilion, purple and brick can be stably printed by changing the mixing ratio of cyan toner and black toner.

On the other hand, in Comparative Examples 1 to 3,
Since the same surface modifier is attached to the toner surface, among the toners constituting the developers in Comparative Examples 1 to 3, the toner having the maximum charge amount and the toner having the minimum charge amount are included. The ratio of the difference between the minimum charge amount and the charge amount of the toner is 20.1% to 36.6%, and the chargeability of each toner becomes uneven, so that the mixed toner becomes uneven. Consumed, the color tone of the printed image changes, the image density decreases,
Problems such as toner adhesion to non-printed areas, large fluctuations in chargeability, and toner scattering occur.

Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the configurations and conditions described in the above-described embodiments and examples, and various changes can be made. is there. For example, the ratio of the difference between the maximum charge amount of the toner and the minimum charge amount of the toner of the present invention to the minimum charge amount of the toner charge amount is not limited to the above numerical values. , 20% or less,
More preferably, it is preferably 15% or less.

Further, in the above description of the embodiments, toners of three hues of yellow, magenta and cyan are used in combination as color toners, but color toners of a different hue system are used. It is also good.

Further, in the above description of the embodiment, the color toners having the negative charging polarities are combined, but the color toners having the positive charging polarities are also preferable. The result is obtained.

Here, the detailed features of the present invention will be described again. (Supplementary Note 1) A color toner obtained by mixing at least three types of color toners having at least different hues each including a binder resin and a colorant and two or more types of toners selected from black toners, and A color toner for electrophotography, characterized in that surface modifiers having different types and / or compositions are attached to the surfaces of two or more types of color toners. (Supplementary Note 2) Of the two or more types of color toners described above, the difference in charge amount per unit weight between the color toner having the maximum charge amount per unit weight and the color toner having the minimum charge amount per unit weight. 2. The color toner for electrophotography according to appendix 1, wherein the ratio of the color toner having the minimum charge amount per unit weight to the charge amount per unit weight is 20% or less. (Supplementary note 3) The color toner for electrophotography according to supplementary note 1 or 2, wherein the three or more types of color toners having different hues are a yellow toner, a magenta toner, and a cyan toner. (Supplementary note 4) The electron according to any one of supplementary notes 1 to 3, wherein the amount of the surface modifier added is 0.1 to 5 parts by weight with respect to 100 parts by weight of each color toner. Color toner for photographs. (Supplementary Note 5) The surface modifier is silica, alumina, titanium oxide, barium titanate, magnesium titanate,
Calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, carbonic acid. 5. The electrophotographic color toner according to any one of appendices 1 to 4, which is an inorganic fine particle selected from calcium, silicon carbide, and silicon nitride. (Supplementary Note 6) A toner cartridge which is used by being set in an image forming apparatus in which a toner image is fixed on a recording medium, and which contains the color toner according to any one of Supplementary Notes 1 to 5. Toner cartridge characterized by. (Supplementary Note 7) An image forming apparatus in which a toner image is fixed on a recording medium, wherein the color toner according to any one of Supplementary Notes 1 to 5 is used.

[0104]

According to the present invention, when two or more kinds of toners selected from a plurality of color toners and black toners are mixed to form a developer, at least the kind or the addition amount of the toners on the surface of each toner is formed. Since one of them has a different surface modifier added to make the charge amount of each toner substantially equal, the mixed toner is consumed evenly, and a stable printed image can be obtained, which results in high image quality. It greatly contributes to the spread of the image forming apparatus.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of measurement results of concentration distribution of a surface modifier of a green toner of Example 1 of the present invention.

FIG. 2 is an explanatory diagram of a schematic configuration of a two-component developing type image forming apparatus.

[Explanation of symbols]

10 photoconductor 20 charger 30 exposure means 40 developing means 41 developer container 43 Developing roller 45 toner hopper 50 transfer device 60 cleaner 70 Static eliminator 80 Flash fixer 81 xenon flash lamp

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuharu Hu             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited F term (reference) 2H005 AA08 AA18 AA21 CA21 CB07                       CB08 CB11 CB13 CB18 EA01

Claims (5)

[Claims] 1. A color toner obtained by mixing two or more types of toner selected from three or more types of color toners and a black toner having different hues each including at least a binder resin and a colorant, and The 2
A color toner for electrophotography, comprising a surface modifying agent having at least one of different types and compositions attached to the surface of at least one type of color toner. 2. A color toner having a maximum charge amount per unit weight among the two or more types of color toners,
The ratio of the difference in charge amount per unit weight from the color toner having the minimum charge amount per unit weight to the charge amount per unit weight of the color toner having the minimum charge amount per unit weight is 20%. The color toner for electrophotography according to claim 1, wherein: 3. The surface modifier is silica, alumina,
Titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide The color toner for electrophotography according to claim 1 or 2, which is an inorganic fine particle selected from zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. 4. A toner cartridge which is used by being set in an image forming apparatus for fixing a toner image onto a recording medium, the color toner containing the color toner according to claim 1. Toner cartridge characterized in that. 5. An image forming apparatus for fixing a toner image onto a recording medium, the image forming apparatus according to claim 1.
An image forming apparatus using the color toner according to the item 1.