JPH06161152A - Color toner - Google Patents

Abstract

PURPOSE:To provide toner excellent in material dispersibility and coloring performance for the efficient manufacture of color toner and moreover stable in electrification and excellent in fluidity without cohesion so as to form an image with little fog, and provide color toner with vivid color sufficiently displaying the color of coloring material. CONSTITUTION:Toner contains binding resin and wax, and dye or pigment is added to uncolored grain of 3-20mum in average grain diameter by grinding for coloring. As a coloring method, uncolored grain is dispersed in a solvent, together with dye or pigment, and heated and agitated to color the uncolored grain; or dye or pigment is mixed in the uncolored grain by a dry method, and the outer shell of the uncolored grain made core grain is covered with colored grain for coloring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry developer for an image recording device used in copying machines, printers and the like. More specifically, the present invention relates to a color dry developer of an image recording apparatus that indirectly fixes a dry developer on a recording member or directly forms an image on the recording member based on image information extracted as an electric signal.

[0002]

2. Description of the Related Art Conventionally, electrophotographic methods and electrostatic recording methods used in copying machines, printers and the like have been widely used as image recording methods, and most of dry developers are used in this field. It was As a general method of electrophotography using a dry developer, an electric latent image is formed on a photoconductor formed of a photoconductive substance, and the latent image is developed with the dry developer. Let it be a visual image. This is as it is or after being transferred, it is fixed on a recording medium on which an image is formed by heating and pressure. As a dry developer used in such a method, development is performed only with colored particles containing a resin component and a pigment.
There are roughly classified two-component dry developers, two-component dry developers in which particles such as ferrite and glass beads are mixed with colored particles used in the one-component dry developer.

As the color toner, either a one-component dry developer or a two-component dry developer can be used.
It is difficult to realize a color toner only with the component-based developing method, because there is no colorless and transparent material of magnetic powder having satisfactory magnetic characteristics. Therefore, it is necessary to use a non-magnetic type to enable color toner with one component. The toner has the same structure whether it is a non-magnetic one-component developer or a two-component developer. In the case of a non-magnetic one-component developer, the developer is composed only of toner containing colored particles, but in the case of a two-component developer, a carrier is mixed with a non-magnetic toner. It is necessary to color each color toner containing colored particles, and three or four types of developers are required. Conventionally, toner production has involved the steps of mixing, kneading, pulverizing, and classifying materials including coloring materials, so that it is necessary to individually produce each of these four types of toner from the initial stage.

[0004]

However, according to the conventional manufacturing method, the resin which is the main component contained in the toner, the wax which brings the releasing effect of the recording member and the fixing roller at the time of fixing, and the coloring agent are used. Dyes and pigments will be mixed at the same time. The mixed material can be kneaded by a heating kneader, pulverized by jet air, and classified to produce a toner having a particle size of about 10 μm.
When forming a color image using an electrophotographic method, three color toners of yellow, magenta, and cyan are required.
If necessary, a color image is formed with four color toners including black toner. When these three-color or four-color toners are manufactured using the same production equipment, careful cleaning is required in order to avoid color mixing in the steps of kneading, crushing, and classification. Cleaning the device consumes a lot of labor and time and deteriorates the production efficiency. Also, if one production facility is used for each color, the production facility cannot be used effectively, and as the facility cost increases,
Toner production costs rise.

When a colorant such as a pigment or dye is mixed with a binder resin, only the coloring material existing on the surface of the toner or near the surface of the toner reflects light to recognize each color. However, the coloring material existing inside the toner does not work effectively for recognizing the color. In the conventional manufacturing method, an unnecessary coloring material was included because the coloring material contained therein was also mixed together.

An object of the present invention is to improve the efficiency of production of color toner, and to provide a toner having excellent dispersibility of materials and coloring properties. Another object of the present invention is to provide a color toner having stable chargeability, excellent fluidity without aggregation, and forming an image with less fog.

A further object of the present invention is to provide a vivid color toner in which the color of the coloring material is sufficiently exhibited.

[0008]

In order to achieve this object, the dry developer of the present invention contains a binder resin and a wax and is pulverized into uncolored particles having an average particle size of 3 to 20 μm. Color by adding dyes or pigments. As a coloring method, the uncolored particles are dispersed in a solvent together with a dye or a pigment, and the mixture is stirred in a heated state to be colored into uncolored particles, or a dye or a pigment is added to the uncolored particles by a dry method. The above object is achieved by mixing and coloring the uncolored particles as core particles by covering the outer shell with colored particles. The color toner of the present invention has first and second electrodes with an insulating layer interposed therebetween, and an opening is provided between the electrodes to form the first and second electrodes.
It can be used in an image forming apparatus provided with a control unit that forms an electric field between the electrodes.

[0009]

According to the dry developer of the present invention having the above-mentioned constitution, since the binder, the wax, and the charge control agent are composed of non-colored particles, the crushed and classified particles themselves are not colored. Particles are formed. The particles at this stage can be colored in any color and thus also in yellow, magenta, cyan and even black. The colorless particles are mixed with a dye-dispersed solvent and stirred with heating, whereby the colorless particle surfaces are colored with the dye simultaneously dispersed in the solvent. Since the container for coloring can be washed by passing the same solvent as that for coloring, the color can be changed very easily to produce the colored particles. The colored particles are colored by incorporating a dye into the inside of the colorless resin particles, and are in contact with the light and air through the surface of the resin particles, which is very effective for light resistance and deterioration resistance.

If the above method is a method for coloring colorless particles by a wet method, there is a coloring method by a dry method. A pigment or a dye having a particle diameter of ⅕ or less of the particle size is mixed with the colorless ground particles to form a film made of the dye or pigment on the surface of the colorless ground particles.

When it is judged that the coloring density is low only by the wet method and the dry method alone, or when the weather resistance is not satisfactory, the coloring can be achieved by using the wet method and the dry method in combination. A fluidity adjusting agent such as an inorganic external additive may be externally added to the colored particles to obtain a toner having excellent chargeability and powder characteristics.

[0012]

The present invention will be described in detail below.

The colorless particles in this embodiment are composed of at least 80 to 95 parts by weight of a binder resin and 3 to 10 parts by weight of wax, and 1 to 10 parts by weight of a charge control agent may be mixed if necessary. good.

The binder resin is a resin obtained by chemical synthesis, and specific examples thereof include polystyrene, styrene-acrylic acid type copolymers, styrene-maleic acid type copolymers, polyacrylate type resins, polyesters,
Resin particles polymerized from polyethylene or the like or a mixture thereof are preferably used, but are not limited to these examples.

The wax is used when the toner is fixed on the recording member by the heat roll, and plays the role of preventing the toner from adhering to the roller side when the toner is melted by the heat roll. No wax is required if the fixing method does not contact the heat roll with the heat roll. As an example of the wax, polyethylene, microclostaline wax, ethylene-vinyl acetate copolymer and the like can be preferably used.

Examples of charge control agents include dyes of metal-containing complexes, azo dyes, quaternary ammonium salts, sulfonates and the like. It can be used as a mixture with a binder resin which is the main component of the toner particles, or the effect can be expected by attaching a charge control agent to the surface.

Particles produced by mixing the materials, kneading with a kneader, pulverizing and classifying are 10 with a Shimadzu flow tester.
In the measurement result under the load of kg, the softening temperature is 60 to 100.
C., and the outflow starting temperature is preferably in the range of 120 to 180.degree. It is common to use a fixing roller when fixing the toner on the recording member.However, in order to avoid toner adhesion to the fixing roller, both the softening temperature and the outflow starting temperature are the same as those of the conventionally used toner. It is desirable to be in the above setting area.

The colorless resin particles of this embodiment preferably have an average particle size of 3 to 20 μm, more preferably 4 to 10 μm. 20 μm
The above particle size causes clogging of the aperture electrode that constitutes the printing portion of the image forming apparatus in which the dry developer according to the present exemplary embodiment should be used, and the toner is handled dry when the particle size is 3 μm or less. In this case, the scattering of the toner into the apparatus and the scattering of the toner to the white portion at the time of recording on the recording member are observed. The particle size distribution used in this example is judged by the volume-based particle size measured by Multisizer II of Coulter Counter.

Since such colorless resin particles are white particles, it is necessary to dye the colorless resin particles in an arbitrary color. Two kinds of dyeing methods are used. A stirring device using a stirrer is used, a colorless resin particle and a dye are simultaneously dispersed in a solvent, and a wet method for dyeing the resin particle and a pigment or colorless resin particle are used. There are two methods of externally adding a dye and coloring the surface of colorless pulverized particles by the impact force of a rotating blade. In the case of the first wet method, the solvent is water, methyl alcohol, ethyl alcohol, acetone, toluene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, hexane, benzene,
Solvents such as xylene can be used alone or as a mixture, and must be adjusted so that the polymer particles are not dissolved in the solvent.

Dyes used in the wet method include azobenzene, hydroxyazobenzene, aminoazobenzene,
Azo dyes represented by methylaminoazobenzene, dimethylaminoazobenzene, dimethylaminodifluoroazobenzene, dimethylaminoacetylazobenzene, phenylaminonitroazobenzene, acylaminoanthraquinone, anthraquinone imide, anthraquinonecarbazole, dihydroazine, acridone, thioxanthone, flavanthrone, pyranthrone. , Dibenzoanthrone, anthraquinone dyes represented by antoanthrone, indigo, methylindigo, dimethylindigo, dichloroindigo, hexachloroindigo, methylisoindigo, diaminothioindigo, dibenzothioindigo, indigo dyes represented by perinaphthothioindigo, Phthalocyanine, hexadecahydrophthalocyanine, tetraphenylphthalo Cyanine and Mg of these phthalocyanine dyes, Cr, Fe, Ni, Cu, phthalocyanine dyes represented by metal complexes of Zn, and the like.

The beaker is adjusted and filled with a solvent for dyeing the resin particles, and the resin particles are heated in a water bath at 30 to 90 ° C. to a temperature at which the solvent does not boil and the resin particles do not melt. And disperse the dye. The resin particles are mixed at a ratio of 5 to 50 parts by weight with respect to 100 parts by weight of the solvent, and the resin particles are dyed for 10 minutes to 2 hours while stirring with a stirrer. If the ratio of the resin particles dispersed in the solvent exceeds 1/2, the viscosity of the dispersed solution increases and dyeing becomes impossible, and if the ratio is 1/20 or less, the ratio of the dye in the solvent becomes low. This is because the dyeing on the resin particles becomes dull. On the other hand, in order to perform deep dyeing, the amount of the dye added to the solvent is preferably 2 to 30 parts by weight with respect to 100 parts by weight of the resin particles.

This is because dyeing becomes thin when the mixing amount is 2 parts by weight or less, and the viscosity of the dyeing solution becomes high and dyeing cannot be performed when the mixing amount is 30 parts by weight or more. The colored resin particles are separated from the dyeing solvent and dried. The dried colored particles are present as agglomerates, and at the same time when the fluidization modifier is added and mixed by stirring, the agglomerates are loosened to become primary particles of 10 μm. The solvent used for dyeing can be used again for coloring other colorless resin particles after adjusting the dye concentration.

In another dyeing method, colorless resin particles are dry-mixed with a dye or pigment, and the pigment is impregnated on the surface of the resin particles with an impact force given by a rotating blade to dye. Fill a mixer with rotating blades, 1
It is possible to color the resin particles by injecting a dye or a pigment onto the surfaces of the resin particles at a rotational speed of 000 to 10,000 rpm for a mixing time of 1 minute to 1 hour. The blade rotating at high speed gives an impact force to the particles, and the heat generated by the impact forms a thin layer of the coloring material on the surface of the resin particles. As the coloring material, the dye given in the wet method as the first method, and as the pigment, carbon black (black), yellow lead, benzidine yellow, Hansa yellow (yellow), quinacridone red, lake red, brilliant carmine, rhodamine. Lake (red), methyl violet lake, phthalocyanine blue (blue), phthalocyanine green, malachite green (green) and the like.

In the case of dry coloring, the blade shape used in the mixer has many opportunities to collide with particles, and the coloring material is driven onto the colorless resin particle surface by rotating at a higher speed to remove the coloring material from the particles. The resin particles should be attached so that they will not come off easily. On the other hand, the fluidization modifier is mixed with the colored resin particles, but the blade shape and rotation speed of the mixer at that time are different from the coating of the coloring material on the resin particles, and there are few collision opportunities, It is carried out under the condition that the rotation speed is low and a sufficient fluidization modifier is mixed.

When the dyeing is carried out by the dry method, the dyed resin particles do not fade, but the presence of the pigment on the surface of the resin particles makes the fixability on the recording member poor.
The most preferable amount of coloring material is about 0.5 to 10 parts by weight based on 100 parts by weight of the resin particles. In addition, it is preferable to use sufficiently small coloring material particles that are 1/5 or less of the resin particles. For example, if the resin particles are 10 μm, the coloring material particles of 2 μm or less are preferable, and further 1 μm.
It is desirable to use the following colored material particles.

Unless the resin particles are sufficiently colored by the wet coloring method, it is possible to use both wet coloring and dry coloring in combination. The colorless resin particles dyed by the wet method are colored, and after the colored particles are dried,
Similar to coloring colorless particles by the dry method, 100
By adding 0.1 to 7 parts by weight of dye or pigment to 1 part by weight of colored particles, the particle surface is colored by utilizing the mechanical impact force and heat given by the rotating blade, Sufficient and vivid colored particles can be produced.

It is also possible to mix various additives in addition to the fluidity adjusting agent with such dyed particles. Finely powdered hydrophobic silica, titanium oxide, inorganic oxides as fluidization regulators such as aluminum oxide, metal soaps, fluorine-based fine powder particles, various additives such as inorganic carbides, etc., and each is used as necessary. It

When the image recording apparatus of this embodiment is filled with the toner configured as described above, the image recording apparatus will be described.

Inkjet printing is a non-impact printing technique similar to the electrophotographic method. In this method, when pressure is applied to the liquid ink by a vibrator such as a piezoelectric element, the liquid ink in the nozzles jumps out, jumps in the electric field and adheres onto the recording paper. Inkjet printing does not have the problems such as the complexity of device maintenance and the enlargement of the device compared to the electrophotographic method, but it is necessary to use a special paper because the ink splattered on the recording paper can be seen. At the same time, since the ink is supplied from the nozzle, there is a problem that clogging occurs due to drying of the ink at the tip of the nozzle.

As a technique combining the advantages of electrophotography and ink jet printing, the method proposed in US Pat. No. 3,689,935 is practical, and is a method of forming an image without using a photoconductor. It is possible to obtain high resolution image quality at a cost.

According to this method, two electrodes are provided through the insulating layer, and the means for controlling the toner in the dry developer having the openings in which holes are formed in rows is used, It controls the passage of the charged toner, and forms an image by the toner according to the image information on a recording member arranged at a position opposed to each other with a dry developer supply unit and a control unit having an opening interposed therebetween. . The configuration of the image forming apparatus will be described in detail below.

As shown in FIG. 1, in the aperture electrode 1, the reference electrode 3 is provided on the toner supply device side of the insulating layer 2 and the recording member 10 is provided.
It has a control electrode 4 on the side. A toner supply device 20 is provided on the side of the reference electrode 3 with the aperture electrode 1 interposed therebetween, and a back electrode 11 is provided on the side of the control electrode 4 together with the recording member 10.

FIG. 2 shows a state of the aperture 6 penetrating from the reference electrode 3 to the control electrode 4 through the insulating layer 2. Aperture electrode 1 having openings arranged in rows
By the action of the reference electrode 3 and the control electrode 4, electrolysis is formed in the aperture 6 to control the toner flow.

A cloud generator 20 is arranged on the reference electrode 3 side of the aperture electrode 1, and a brush roller 28 and a supply roller 23 arranged in parallel with the brush roller 28 are placed in a toner case 21 in which toner 22 is stored. It is arranged. The brush roller 28 and the supply roller 23 are in contact with each other. The supply roller 23 is provided with a restriction blade 26 that restricts the toner 22 supplied from the toner case 21. The brush scraping blade 24 is in contact with the brush roller 28 before the brush of the brush roller 28 reaches the vicinity of the aperture 6. This brush scraping blade 24
It is connected to a negative high voltage power supply 25. The reference electrode 3, the brush roller 28, and the toner case 21 are grounded.

On the control electrode 4 side of the aperture electrode 1, a back electrode 11 that rotates while contacting the recording member 10 is arranged and connected to a positive high voltage power source 12. Back electrode 1
A fixing device 13 is disposed at the destination of the recording member 10 that is conveyed by the rotation of the toner 1.
Is responsible for the establishment of. The control electrode 4 of each aperture 6 is
Each is connected to a control voltage drive circuit 8 that generates a voltage according to an image signal.

Next, the operation of the image forming apparatus will be described.

By the rotation of the brush roller 28 and the supply roller 23, the toner 22 is carried on the brush of the brush roller 28 by the amount of the toner regulated by the regulation blade 26. The toner 22 is conveyed toward the brush scraping blade 24 by the rotation of the brush roller 28. Since a high voltage is applied to the brush scraping blade 24 from the negative high voltage power supply 25, an electric field is formed between the brush scraping blade 24 and the brush roller 28 which is grounded. While the negative ions ionized by the strong electric field in the space near the brush scraping blade 23 flow toward the brush roller 28, they adhere to the toner 22 and are strongly charged. The toner 22 is forcibly charged by the voltage applied between the brush scraping blade 24 and the brush roller 28, and further, the toner between the toner 22 and the brush of the brush roller 28 is rubbed between the toner 22 and the supply roller 23. It becomes charged and becomes a large amount of charge.

The brush scraping blade 24 has another role to strongly repel the brush of the brush roller 28. When the brush is strongly repelled, the charged toner 22 attached to the brush leaves the brush and flies in the air.
Since this operation continues intermittently, the cloud state of the toner 22 always exists near the aperture.

On the other hand, the recording member 10 on which an image is formed is
It is conveyed between the control electrode 4 and the back electrode 11 as the back electrode 11 rotates. When a positive voltage is applied to the control electrode 4 in accordance with the image information given from the control voltage drive circuit 8 with the conveyance of the recording member 11, a potential gradient from the reference electrode 3 of the aperture 6 to the control electrode 4 side. And the negative toner 22 repelled by the brush scraping roller 24 passes through the aperture from the cloud shape, and the recording member 10
Fly to. At this time, a positive high voltage power source 1 is applied to the back electrode 11.
Toner 2 charged negatively because high voltage is applied from 2
2 is guided to the recording member 10 and adheres to the recording member 10 by the electrostatic force of the toner 22. In the electrode to which the image information is not applied from the control voltage drive circuit 8, the control electrode 4 is grounded or is set to a negative potential, so that the toner 22 does not pass through the aperture 6. The toner image thus formed on the recording member 10 is conveyed to the back electrode 11 and is conveyed to the fixing device 13, and is firmly fixed on the recording member 10.

In this embodiment, the negative toner is used for explanation, but positively charged toner can be used if the voltage applied to the control electrode is negative.

A method of manufacturing the toner of this embodiment used in the image forming apparatus detailed above will be described below with reference to experimental examples.

Experimental Example 1 100 parts by weight of a styrene-acrylic copolymer (UNI3000 manufactured by Sanyo Kasei), 5 parts by weight of polyethylene wax (550P manufactured by Sanyo Kasei) and 2 parts by weight of a charge control agent (E-84 manufactured by Orient Chemical Co., Ltd.) were mixed. , And kneading with a heating kneader, and pulverizing and classifying with a jet air type pulverizer equipped with a collision plate to disperse 10 μm colorless resin particles in water of 1000 CC heated to 90 ° C. Then, dyeing was carried out while adding 5 parts by weight of Kayaron polyester manufactured by Nippon Kayaku while stirring for 30 minutes. After the dyeing, only the resin particles which were dried and dyed were taken out. Dyeing particles 10
1 part by weight of Kayaron polyester was mixed with 0 part by weight, and 2000 rpm30 was obtained using a mechanomill manufactured by Okada Seiko.
External dyeing was performed on the surface of the dyed particles under the condition of minutes. To 100 parts by weight of the colored particles, 0.5 part by weight of hydrophobic silica was mixed using a Henschel mixer to obtain a toner. The charge amount of the obtained toner was -21 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having openings on the electrodes, white areas were not covered and an image with excellent gradation could be obtained. The density obtained in the black solid part on the test chart is
It was 1.5.

Experimental Example 2 In Experimental Example 1, 7 parts by weight of Oplas Yellow 130 was added as a dye for wet dyeing, and dyeing was performed for 1 hour with stirring. After dyeing, 100 parts by weight of the dyed particles were colored with 2 parts by weight of Fat Yellow 3G on the surface of the particles under the same conditions as in Experimental Example 1 to obtain yellow particles.

The toner obtained by mixing 0.5 part by weight of hydrophobic colloidal silica with 100 parts by weight of the yellow particles in a mixer had a charge amount of -23 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening on an electrode, a white portion was not covered and an image excellent in gradation could be obtained. The density obtained in the solid area on the test chart was 1.4 as measured by a reflection type Macbeth densitometer.

Experimental Example 3 In Experimental Example 2, 5 parts by weight of oil pink was added as a dye for wet dyeing, and dyeing was performed for 30 minutes with stirring. The charge amount of the toner obtained by mixing 0.5 part by weight of hydrophobic colloidal silica with 100 parts by weight of the magenta particles by a mixer was -25 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening on an electrode, a white portion was not covered and an image excellent in gradation could be obtained. The density obtained in the solid area on the test chart was 0.8 as measured by a reflection type Macbeth densitometer.

Experimental Example 4 Dyeing was carried out under the same conditions as in Experimental Example 2 except that the dye used for wet dyeing was 5 parts by weight of TO Cyan 1.
The charge amount of the toner obtained by mixing 0.5 part by weight of hydrophobic colloidal silica with 100 parts by weight of the dyed cyan particles with a mixer was −19 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening on an electrode, a white portion was not covered and an image excellent in gradation could be obtained. The density obtained in the solid area on the test chart was 1.8 as measured by a reflection type Macbeth densitometer.

Comparative Example 1 Fat yellow 3G was added to the yellow dyed particles dyed by the wet method of Example 2 and surface coloring was not performed by the dry method. Similarly, for the dyed particles, 0.5 parts by weight of hydrophobic silica fine powder was mixed with 100 parts by weight of the dyed particles to obtain a toner. The charge amount of this toner was −20 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having openings on the electrodes, white areas were not covered and the density of solid areas was 1.2.

Experimental Example 5 In Experimental Example 1, a binder resin, styrene-acrylic copolymer, polyethylene wax, and charge control agent 4 were used.
8 μm of colorless resin particles were formed from parts by weight (FCA-1001N manufactured by Fujikura Kasei). The colorless resin particles 100
Part by weight was dispersed in 1000 cc of methanol heated to 40 ° C., and 5 parts by weight of Varifast Yellow was added, and dyeing was performed with stirring using a stirrer for 1 hour. After dyeing, only the colored particles which were dried and dyed were taken out. 1 part by weight of Fat Yellow 3G was mixed with 100 parts by weight of the dyed particles, and a charge control agent and a coloring material were externally added to the surface of the dyed particles under the condition of 2500 rpm for 1 hour using a mechanomill manufactured by Okada Seiko. To 100 parts by weight of the dyed particles, 0.5 parts by weight of hydrophobic silica was mixed using a Henschel mixer to obtain a toner. The charge amount of the obtained toner was −35 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening on an electrode, a white portion was not covered and an image excellent in gradation could be obtained. The density obtained in the solid area on the test chart was 1.5 as measured by a reflection type Macbeth densitometer.

Experimental Example 6 Varifast yellow used in Experimental Example 5 was changed to 5 parts by weight with TO magenta 2 and wet dyeing was performed, and dry surface coloring by mechanomill was not performed. The resulting toner had a charge amount of −37 μC / g.

When this toner was image-outputted by an image-forming apparatus equipped with a developing device having openings formed on the electrodes, white areas were not covered and an image with excellent gradation could be obtained. The density obtained in the solid area on the test chart was 0.9 as measured by a reflection type Macbeth densitometer.

Experimental Example 7 The Varifast Yellow used in Experimental Example 5 was changed to 5 parts by weight with TO cyan 1 and dyed by wet method, and surface coloring by mechanomill was not performed. The charge amount of the obtained toner is
It was −38 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening formed on an electrode, a white portion was not covered and an image excellent in gradation could be obtained. The density obtained in the solid area on the test chart was 1.7 as measured by a reflection type Macbeth densitometer.

Comparative Example 2 Varifast yellow used in Experimental Example 5 was changed to 5 parts by weight with KP Yellow HGL-SF and wet dyeing was performed, and surface coloring by mechanomill was not performed. The obtained toner had a charge amount of −33 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having openings on the electrodes, white areas were often covered and an image with unclear resolution was obtained. The density obtained in the solid area on the test chart was 1.0 as measured by a reflection type Macbeth densitometer.

Comparative Example 3 10 parts by weight of Varifast Yellow was mixed with a styrene-acrylic copolymer which is the binder resin used in Experimental Example 5, polyethylene wax, and a charge control agent in a mixer,
The mixture was kneaded using a heating kneader, pulverized with a jet air pulverizer equipped with a collision plate, and classified to form 10 μm colored particles.

To 100 parts by weight of the colored particles, 0.5 part by weight of hydrophobic silica was mixed using a mixer to obtain a toner. The charge amount of the obtained toner was −25 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having openings on the electrodes, white areas were not covered and an image with good gradation was obtained. The density obtained in the solid area on the test chart was 1.4 as measured by a reflection type Macbeth densitometer.

Comparative Example 4 Colored particles were obtained by similarly pulverizing and classifying with the addition amount of Varifast Yellow of Comparative Example 3 being 5 parts by weight. The charge amount of the toner obtained by mixing 0.5 part by weight of hydrophobic silica with a mixer was -30 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having openings on the electrodes, white areas were not covered and an image with good gradation was obtained. The density obtained in the solid area on the test chart was 0.8 as measured by a reflection type Macbeth densitometer.

Experimental Example 8 The colorless resin particles obtained in Experimental Example 5 were not subjected to wet dyeing, but only to a dry surface coloring operation. 5 parts by weight of Daiiroxide Color Black manufactured by Dainichiseika Co., Ltd. was mixed with 100 parts by weight of the resin particles, and a pigment was externally added to the surface of the resin particles by using a mechanomill manufactured by Okada Seiko at 2500 rpm for 1 hour. This dyed particle 1
0.5 parts by weight of hydrophobic silica was mixed with 00 parts by weight using a Henschel mixer to obtain a toner. The charge amount of the obtained toner was −31 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening on an electrode, there was a problem in the fixing property, but the white part was not covered, and an image excellent in gradation was obtained. I was able to get The density obtained in the solid black portion on the test chart was 1.5 as measured by a reflection type Macbeth densitometer.

Experimental Example 9 The colorless resin particles obtained in Experimental Example 3 were added in the same manner as in Experimental Example 8.
The surface coloring was performed by a dry method without dyeing by a wet method. Carbon black 3 to 100 parts by weight of resin particles
A part by weight was added, and the mixture was stirred and mixed in a mechanomill at 2500 rpm for 1 hour to adhere the colorant to the surfaces of the colorless resin particles. The charge amount of the obtained toner was -25 μC / g.

When this toner was image-outputted by an image forming apparatus equipped with a developing device having an opening on an electrode, a white portion was not covered and an image excellent in gradation could be obtained. The density obtained in the black solid part on the test chart is
It was 1.7 as measured by a reflection type Macbeth densitometer, but a slight fixing offset occurred.

The results of the above experiments are summarized in the table below.

[0071]

[Table 1]

[0072]

As is apparent from the above description, according to the dry developer of the present invention, since colorless resin particles can be colored in any color, one kind of toner should be produced by pulverization and classification. Good. One operation is required to make one color toner, and four to make four color toners.
Although the production operation was required once, the color toner of the present invention can produce four types of toner by one pulverization and classification operation.

Since the colorant is present only on the surface of the colorless resin particles, a color toner having satisfactory density and saturation can be obtained by using a small amount of expensive dye or pigment as compared with the resin binder. Obtainable.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a color toner of the present invention.

FIG. 2 is a diagram of an aperture electrode when viewed from above.

[Explanation of symbols]

 1 Aperture electrode 2 Insulating layer 3 Reference electrode 4 Control electrode 6 Aperture 10 Cloud generator 22 Toner

Claims (4)

[Claims] 1. A color toner comprising a binder resin and a wax, which is colored by adding a dye or a pigment to uncolored particles having an average particle diameter of 3 to 20 μm by pulverization. 2. The color toner according to claim 1, wherein the uncolored particles are dispersed in a solvent together with a dye or a pigment, and the particles are stirred while being heated to color the uncolored particles. 3. The color toner according to claim 1, wherein the non-colored particles are dry-mixed with a dye or a pigment, and the non-colored particles are used as core particles to coat the outer shell of the color particles with the colored particles. 4. An image forming apparatus having first and second electrodes via an insulating layer, an opening provided between the electrodes, and control means for forming an electric field between the first and second electrodes. The color toner according to claim 1, which can be used for.