JPH04226476A - Toner for electrophotography and production thereof - Google Patents

Abstract

PURPOSE:To enable stable feed and to improve the stability of a formed image. CONSTITUTION:One or plural kinds of additives 12 for regulating flowability, releasability, etc., are added to base particles 11 based on a binder to prepare additive added particles 1. These particles 1 are heated by suspension in hot air 6 to melt the surfaces of the particles 1 and the additives 12 are incorporated and held near the surfaces of the base particles 11 to obtain a toner 7. Since the conventional toner is produced by pulverization and classification, the shape is irregular. By this method, the surface of the toner 7 is made smoother and the flowability of the toner 7 is improved because the surface of the toner 7 is melted once in the hot air 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner used in electronic copying machines, laser printers, etc., and a method for producing the toner.

0002

[Prior Art] Conventionally, electrophotographic toner (hereinafter referred to as toner) used in copying machines such as electronic copying machines and laser printers has a binder as a binding agent, a coloring agent, and an interface as a charge control agent. It contains an activator and a wax as a release agent dispersed therein, and is formed into a predetermined particle size. The manufacturing method is to knead the binder, colorant, charge control agent, and release agent to disperse, or add internally, to the binder, and after cooling, crush and classify to produce toner of any particle size. has been done. Note that, in order to improve fluidity, a toner in which fluidizing agent particles such as fine silica gel powder are externally added, that is, adhered to the surface of the toner, is sometimes used.

0003

[Problems to be Solved by the Invention] However, the above-mentioned toner includes a pulverization and classification process in its manufacturing process.
The outer shape of the obtained toner is not spherical but irregular and irregular, resulting in poor fluidity. In addition, even if fluidizing agent particles are externally added as an additive to improve the fluidity function of such irregularly shaped toner, the toner will be damaged due to the fluidizing agent merely adhering to the toner. It is easy to peel off from the toner, and the fluidity function of the obtained toner is unstable.

[0004] Therefore, the fluidity of the above-mentioned toner is poor;
Or, because it is unstable, for example, near the toner discharge port in the hopper of an electronic copying machine, the shape and surface condition of the toner retained in the hopper, which gradually decreases as it is consumed, suddenly becomes large, like a landslide, when it reaches a certain stage. give rise to changing phenomena.

[0005] As a result, the amount of toner on the outlet of the hopper becomes unstable, making it impossible to stably supply toner.
This poses a problem in that the resulting image becomes unstable.

Therefore, an object of the present invention is to provide an electrophotographic toner that improves fluidity and can stably exhibit functions such as fluidity, thereby providing stable images, and to provide a stable electrophotographic toner. The object of the present invention is to provide a manufacturing method that can obtain the desired results.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the inventors of the present application have conducted extensive research and found that they suspend binder particles to which additives have been externally added in hot air. By melting the surface, it is possible to obtain a toner with improved fluidity in which the particle shape approaches a spherical shape, and it is also possible to incorporate externally added additives into the vicinity of the surface of the toner. They discovered that it could be held more strongly and completed the present invention.

That is, the electrophotographic toner according to claim 1 is obtained by mixing an additive having a coloring function and a granular material mainly containing a binder to obtain a mixture, and then heating the mixture. The method is characterized in that the surface of the granular material is melted, and the additive is added near the surface of the granular material.

In the electrophotographic toner according to the second aspect, an additive for adding a function such as coloring is attached to the surface of a granular material mainly containing a binder, and then the granular material is suspended in hot air. The additive is added to a predetermined position between the surface of the granule and the part included in the granule.

[0010] The method for producing an electrophotographic toner according to claim 3 includes a first step of mixing an additive that adds a function such as coloring with a granular material mainly containing a binder to obtain a mixture; The mixture is suspended in hot air to melt the surface of the granules,
The present invention is characterized in that an electrophotographic toner is obtained by a second step of adding the additive to the vicinity of the surface of the granular material.

The method for producing an electrophotographic toner according to claim 4 includes a first step of mixing an additive that adds a function such as coloring with a granular material mainly containing a binder to obtain a mixture; The mixture is suspended in hot air to melt the surface of the granules,
The present invention is characterized in that an electrophotographic toner is obtained by a second step of adding the additive to a predetermined position between the surface of the granular body and the part included in the granular body.

[0012] The method for producing an electrophotographic toner according to claim 5 includes a first step of kneading, pulverizing, and classifying a colorant, a charge control agent, a release agent, and a binder to prepare granules having a predetermined particle size. a second step of mixing the granules and a fluidizing agent to obtain a mixture; and floating the mixture in hot air at a temperature at which the binder melts to melt the surface of the granules. Then, the toner for electrophotography is obtained by a third step of cooling and solidifying the surface and adding the fluidizing agent near the surface of the granular material.

The method for producing an electrophotographic toner according to claim 6 includes kneading, pulverizing, and pulverizing a colorant, a charge control agent, and a binder.
A first step of classifying to produce granules of a predetermined particle size, and a second step of mixing the granules and a mold release agent to obtain a mixture.
The present invention is characterized in that an electrophotographic toner is obtained by a third step in which the mixture is suspended in hot air at a temperature at which the release agent is softened to smooth the surface of the granules.

Next, a more specific manufacturing method will be described. First, granules are prepared by mixing a binder with one or more additives such as a coloring agent, a charge control agent, and a mold release agent, and performing kneading, pulverization, and classification steps. In addition,
Binder particles having a predetermined particle size may be used as the granules.

[0015] Next, the granules, a coloring agent, a charge control agent,
A mixture is obtained by mixing with one or more of additives such as a mold release agent. At this time, these additives may be in an externally added state adhering to the surface of the granules. Next, the above-mentioned mixture is injected into an air stream at a temperature at which the binder or mold release agent melts, that is, into hot air, and while it remains in the hot air, the granules in the above-mentioned mixture are formed in the hot air. The surface melts, and the additive present on the surface melts and/or
Or the additive collided with the surface in the hot air,
It is added near the surface by dissolving or entering the granules. In addition, in the above-mentioned, melting includes a glassy substance such as an amorphous resin whose viscosity decreases significantly at a temperature equal to or higher than the glass transition point and becomes liquid. Furthermore, each additive is selected to have affinity with the binder.

[0016] After that, the granules are cooled in an air stream at outside temperature and their surfaces solidify, so that the surface becomes smooth due to surface tension, or its shape becomes more spherical, and the additive is concentrated near the surface. To obtain an electrophotographic toner which is unevenly distributed and retained in the .

However, the temperature of the heated hot air and the residence time of the mixture in the hot air are such that the surface of the granules melts and the additive is incorporated from the surface of the granules into the granules. set to be held in place between the two. In other words, when a fluidizing agent is used as an additive, it is better to distribute it as unevenly as possible on the surface of the toner in order to perform its function. It will be more expensive. Therefore, the fluidizing agent is set at a position that increases its holding strength within a range where its function can be fully exhibited.

[0018] The coloring agent as an additive related to claims 1, 2, 3, 4, 5 and 6 includes, for example, carbon black, copper phthalocyanine, nigrosine dye. , aniline blue, calcooil blue, chrome yellow, ultramarine yellow, methylene blue, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green, oxalate, lamp black, rose bengal, or mixtures thereof can be used.

Further, as the charge control agent as an additive in claims 1, 2, 3, 4, 5 and 6, organic amine compounds, quaternary ammonium compounds and Salicylic acid Cr complex, salicylic acid Zn complex, naphtholic acid Cr complex, dibutyltin oxide, or the like can be used.

Claim 1, Claim 2, Claim 3, Claim 4
As the mold release agent as an additive according to claims 5 and 6, a wax made of polyethylene, polypropylene, paraffin, or the like can be used.

Claim 1, Claim 2, Claim 3, Claim 4
Examples of the binder as an additive according to claims 5 and 6 include styrene copolymer resins such as styrene/acrylic copolymer, polystyrene, and styrene/butadiene copolymer; Ethylene copolymer resins such as polyethylene/vinyl acetate copolymers and polyethylene vinyl alcohol copolymers, as well as phenolic resins, epoxy resins, allyl phthalate resins, polyamide resins, polyester resins, or maleic acid resins. can be used.

[0022] The binder, charge control agent, release agent, and colorant used are not limited to the above-mentioned materials, and other materials can also be used.

[0023]

[Operation] According to the structures of claims 1 and 2, since the surface of the granular material mainly containing a binder as a carrier in an electrophotographic toner is melted and then solidified, the protrusion of the surface is further improved. Since the parts are easily melted, the surface of the electrophotographic toner is smoother than that of electrophotographic toner that has undergone a conventional pulverization process. Therefore, the fluidity of the obtained electrophotographic toner is improved.

Furthermore, in the above-mentioned electrophotographic toner, the surface melts and takes in the additive, and then the surface is cooled and solidified, so that the additive is added while being taken in near the surface. and is maintained. Therefore, in the past, additives were added externally to the toner, that is, the additives were attached to the surface of the granules, so the additives were easily peeled off and the functionality of the toner deteriorated. However, in the electrophotographic toner described above, Since the additive is incorporated into and retained in the electrophotographic toner, it is more difficult to peel off than in the past, and the function of the additive can be stabilized.

According to the methods described in claims 3, 4, 5, and 6, the surface of the granules is melted and the additive is deposited near the surface while the granules are suspended in hot air. Electrophotographic toner can be obtained using the process of incorporating. Therefore, an electrophotographic toner having excellent properties such as good fluidity and being able to stably exhibit functions such as fluidity is produced by utilizing surface tension in hot air. Toner can be stably obtained. Next, the present invention will be explained with reference to Examples, but the embodiments of the present invention are not limited thereto.

[0026]

[Example 1] An example of the present invention will be described below based on FIG. 1. Toner for electrophotography (hereinafter referred to as toner)
has the composition components shown in Table 1 below, for example. The toner is produced by floating a mixture having the composition shown in Table 1 in hot air at a temperature at which the binder melts, melting the surface of the binder, and adding additives such as a colorant, a charge control agent, and a release agent. A molding agent is internally added, that is, held, near the surface of the binder.

[0027]

[Table 1]

Next, a method for producing a toner having the above composition will be explained below. Such toner is manufactured through a process of mixing→surface treatment. That is, the average particle size is 10μ
m of styrene-acrylic copolymer resin [Product name: Hiter SPR1508, manufactured by Sanyo Chemical Co., Ltd.] and the average particle size.
0.1 μm carbon black [Product name: 330R, manufactured by Cabrac Co., Ltd.] and a quaternary ammonium salt with an average particle size of 3 μm [Product name: P-51, manufactured by Orient Co., Ltd.]
and polypropylene [product name: Viscol 550P, manufactured by Sanyo Kasei Co., Ltd.] with an average particle size of 3 μm were weighed in the weight percentage shown in Table 1, and the total amount was 2 kg, and a mixer [product name: Super Mixer SMV20, manufactured by Kawata Co., Ltd.]. The mixer was then operated at room temperature for 5 minutes at a rotational speed of 760 rpm to mix the inputs and obtain a mixture. At this time, as shown in FIG. 1, each of the additives 12 is attached to the surface of the base particle 11 made of the styrene-acrylic copolymer resin, that is, it includes externally added particles 1 to which the additives 12 are externally added.

[0029] Subsequently, the mixture of the externally added particles 1, the base particles 11 that are not externally added, and the additives 12 that are not externally added is subjected to a surface modification device [device name: Surfacing S
system, manufactured by Nippon Pneumatic Industries Co., Ltd.] into hopper 2. From this hopper 2, the above mixture is sent to each nozzle 3.3 by compressed air at a rate of about 1 kg/h.
The above mixture was ejected into hot air 6 while being dispersed. This hot air 6 is formed between a heater-equipped blower 4 that blows air from the bottom to the top in the figure, and a hood 5 that is provided above the heater-equipped blower 4 and sucks the air. The temperature of the hot air 6 was set to about 200° C. by the blower 4 with a heater.

In the hot air 6, since the glass transition point of the binder in the base particles 11 is about 63°C, melting starts from the surface of the base particles 11, and at this time, each additive particle on the surface 12 or each of the additive particles 12 that collided with the surface of the additive particles 12 had an affinity for the base particles 11, so that they were internally added by melting or entering from the surface of the base particles 11.

Thereafter, the internally added base particles 11 rise in the hot air 6 and are cooled by the outside air 8 above, solidifying the surface of the base particles 11 and forming the toner 7. Note that the speed and temperature of the hot air 6 are set within a time period in which the binder in the base particles 11 does not melt to its center during residence in the hot air 6. For example, styrene, acrylic, etc. When using resin particles, the glass transition temperature is 63°C and the average particle size is 10 μm, so the residence time is about 1 second at a hot air temperature of 200°C so that only a predetermined amount on the surface is melted. was set to be.

Thereafter, the cooled toner 7 is suctioned and collected in the hood 5, from which it is sent by air to a cyclone (not shown), where the toner 7 and other fine powders, such as additives, are Each additive 12 that was not
The necessary toner 7 was obtained.

In this manner, the toner 7 contains each additive 1.
2 is internally added and held near the surface, and the surface is once melted while floating in the hot air 6, and then solidified again, so that the surface becomes smoother. In addition, the shape of the toner 7 to which each additive 12 is added becomes closer to a spherical shape.

Therefore, in the toner 7, each additive 12 is unevenly distributed near the surface of the toner 7 and is not present in the center, so that each additive 12 that is on the surface of the toner 7 and exhibits its function is The amount of addition can be reduced. In particular, the fluidizing agent, charge control agent, and release agent perform their functions on the surface of the toner 7, and even if the additive 12 is not present in the center of the toner 7, they can still perform their functions. It does not affect.

This shows that using the above method, each additive 1
As shown in Table 2, even in Toner 7 in which the amount of No. 2 added was reduced compared to the conventional one, the fluidity of the Toner 7 was improved compared to the conventional one. Therefore, the supply of toner 7 in the developing tank or hopper of a copying machine or the like becomes more stable. Therefore, we investigated the changes in the solid black portion of the copy image at the initial stage of use and when using a predetermined amount, and as shown in FIG. was completed.

[0036]

[Table 2]

Here, CCA represents a quaternary ammonium salt as a charge control agent, CB represents carbon black as a coloring agent, and Wax represents polypropylene as a mold release agent.

[0038]

[Table 3]

[0039] Here, the above-mentioned ID is obtained by measuring several solid black areas in a copy image using a Macbeth densitometer.
The average value is taken, and ΔID of initial life is the ID at the beginning of use using our copier and the number of copies that is considered to be the lifespan of the toner carrier in that copier, for example, 80,000 copies. This is the difference from the ID after copying, and when the value is close to zero, there is little change in the copied image and the toner performance is excellent.

Furthermore, Kodak Grayscale gradation refers to the number of gradations that can be distinguished from the Kodak Grayscale chart, and the greater the number of gradations (steps), the better the reproduction of the copied image from the original image. Good sex.

[0041] Conventional toners are manufactured through the following steps: mixing, kneading, pulverizing, and classifying, and the toner has an amorphous shape. However, in the above method, the toner 7 having excellent characteristics as described above is produced by ejecting the mixture into the hot air 6, making it float, and retaining it for about 1 second.
Since it can be manufactured in two steps: mixing (cooling with water) and then surface treatment, it is possible to reduce the time-consuming and labor-intensive steps of kneading, grinding, and classification, which were previously required, thereby shortening the manufacturing time and cost of Toner 7. be able to.

Furthermore, the shape of the toner 7, which is suspended while its surface melts and solidifies, approaches a spherical shape due to surface tension and its surface becomes smooth, so it has excellent fluidity unlike conventional irregularly shaped toner. The toner 7 can be easily and stably produced.

As a result, it is possible to stabilize images obtained by a copying machine.

[Embodiment 2] Another embodiment of the present invention will be described below based on FIGS. 1 and 2. First, the composition shown in Table 1 of Example 1 was subjected to the conventional toner production process of mixing → kneading → pulverization → classification, and as shown in FIG. An average particle size of 10 μm) was obtained.

Next, this mother particle 11 and silica gel (SiO2) fine powder [trade name: R972,
(manufactured by Nippon Aerosil Co., Ltd.) and 0.1% by weight using a mixer (product name: Super Mixer SMV20, manufactured by Kawata Co., Ltd.) to obtain a mixture. At this time, in the mixture, the additive 12 is attached to the surface of the base particles 11.
That is, externally added particles 1 were generated.

Subsequently, the above mixture was subjected to surface treatment using a surface modification device (device name: Surfacing System, manufactured by Nippon Pneumatic Industries Co., Ltd.) under the same conditions as in Example 1 to obtain Toner 7. The obtained toner 7 is
Since the surface is smoother than before, fluidity is improved, and since the silica gel as the additive 12 is incorporated near the surface of the toner 7 and is unevenly distributed, unlike the conventional retention by adhesion, it is more effective. held strongly.

By the way, the shape of conventional toners whose fluidity has been improved by externally adding fluidizing agent particles as additives has been irregular. However, in the above method, since the surface of the toner 7 is once melted and solidified in the hot air 6, its shape approaches a spherical shape due to surface tension, and its surface becomes smooth. Since the additive 12 is taken in and held nearby, the toner 7, which has excellent fluidity and stable fluidity unlike conventional amorphous toners, can be produced easily, quickly, and stably. .

[0048] Therefore, the toner 7 obtained by the above method can have improved and stabilized fluidity, so that it is possible to stably supply the toner in a copying machine or the like. Therefore, changes in image quality obtained even when the copying machine is used for a long period of time are reduced.

Next, in the toner 7, the base particles 11
Since the position of the additive 12 in the air affects the functional performance of the additive 12 and the strength maintained, the temperature of the hot air 6 and the residence time in the hot air 6 are considered as factors for determining the position, and the following An experiment was conducted. Toner 7 was obtained by changing the temperature of hot air 6 in four stages as shown in Table 4.
When the surface was observed, as shown in FIG. 2, as the temperature rose, the additive 12 was incorporated into the base particles 11 and buried therein. Further, the fluidity of each of these toners 7 was measured, and the results are shown in Table 4.

[0050]

[Table 4]

As described above, by adjusting the temperature of the hot air 6, the position of the additive 12 relative to the base particles 11 can be set, and the extent to which the additive 12 functions and the strength to be maintained can be controlled. Furthermore, the same effect can be obtained because the surface condition of the base particles 11 can be controlled by controlling the residence time of the externally added base particles 11. Therefore, in the above method, it is possible to arbitrarily control, for example, the fluidity and the retention strength of such functions of the obtained toner 7 within a predetermined range.

The composition of the above base particles 11 is shown in Table 5. The amount of additive particles 12 added to the base particles 11 was 0.2% by weight, and the other preparation methods were the same as above.

[0053]

[Table 5]

On the other hand, an example of an electrophotographic toner in which a charge control agent is internally added to the surface of the toner by the above method and a method for producing the same will be described. First, among the compositions listed in Table 5 above,
The base particles 11, which are toners without the charge control agent, were produced in the same manner as above, and 0.5% by weight of the above charge control agent as an additive was mixed with the base particles 11, and the same process as above was carried out. The surface treatment was performed by changing the temperature of the hot air 6 in three stages.

The amount of charge of the obtained toner for electrophotography and the density of the black solid area by actual copying were measured, and the results are shown in Table 6.

[0056]

[Table 6]

The measurement of the black solid area in the above results was carried out using the Macbeth densitometer described in Example 1. Further, the charging amount was determined by blow-off method under conditions of 0.2 kg/cm2 and 30 seconds.

[0058] As a result, similar to the fluidizing agent, the hot air 6
It is thought that the position of the additive 12 changes depending on the temperature, and as the temperature increases, the additive 12 is buried in the toner 7.Therefore, as the temperature of the hot air 6 increases, the amount of charge on the toner 7 decreases. decreased. In addition, the higher the amount of charge,
It is thought that the amount of toner 7 transferred to the copy paper decreased, so the density of the solid black portion of the image on the copy paper decreased.

[0059] In this way, even in the charge control agent, hot air 6
It has been found that by controlling the temperature of the toner 7, the amount of charge on the toner 7 can be controlled within a predetermined range.

Therefore, in the above method, by controlling the temperature of the hot air 6 and its residence time, the position of the additive 12 can be controlled to a predetermined position from the surface of the toner 7 to the position buried in the toner 7.

As a result, optimization is achieved between the functionality of the additive 12, which is present on the surface and exerts its function, and the stability of the additive 12, which is incorporated into the interior of the base particle 11 and is more strongly retained. Therefore, the image obtained by the copying machine can be stabilized.

[Embodiment 3] Still another embodiment of the present invention will be described below based on FIG. First, among the compositions shown in Table 1 above, other materials except the release agent were mixed, mixed, kneaded, and mixed using the conventional toner manufacturing method.
After the manufacturing process of pulverization and classification, the base particles (granules) 11
(average particle size of 10 μm) was obtained. Next, the release agent and the base particles 11 are mixed in a mixer [product name: Super Mixe].
rSMV20, manufactured by Kawata Co., Ltd.] to obtain a mixture. At this time, in this mixture, externally added particles 1 were produced in which a mold release agent as an additive 12 was attached to the surface of the base particles 11, that is, externally added thereto.

[0063] The above mixture was processed using a surface modification device [device name: Su
surface treatment was carried out under the same conditions as in Example 1, except that the temperature of the hot air 6 was set to about 150° C., which is the temperature at which the above-mentioned mold release agent softens. Toner 7 was obtained.

In the above toner 7, the release agent is unevenly distributed on the surface of the toner 7, so even though the amount of release agent used is smaller than before, the concentration of the release agent on the surface of the toner 7 increases. It was thought that he was doing so. Therefore, when we investigated the releasability from the fixing roller in a copying machine, we found that the releasability was improved compared to the conventional case where the release agent is uniformly dispersed in the toner.

[0065] Furthermore, it is believed that the melting of the release agent on the surface of the toner 7 after heating on the copy paper acts as a welding agent between the toner 7 and the copy paper. Since the concentration of the release agent was increased, the fixing strength of Toner 7 was investigated, and it was found that the fixing strength was improved compared to the conventional one.

In the above method, the toner 7 is produced by ejecting the mixture into the hot air 6 and allowing it to stay there for about 1 second. Therefore, the toner 7 having the excellent properties as described above can be obtained quickly and stably. Furthermore, since fluidity and fixing properties are improved, images obtained in a copying machine or the like can be stabilized.

[0067]

[Effects of the Invention] The toner for electrophotography according to claim 1 is obtained by mixing an additive having a function such as coloring with a granular material mainly containing a binder to obtain a mixture. The mixture is heated to melt the surface of the granular material, and the additive is added near the surface of the granular material.

[0068] As a result, conventional electrophotographic toners are manufactured through a pulverization process, resulting in an amorphous shape and deterioration of the fluidity of the electrophotographic toner. However, with the above structure, the surface of the granules is Since it is melted, the surface of the obtained electrophotographic toner becomes smoother, and therefore, the fluidity of the electrophotographic toner can be improved.

[0069] In addition, conventionally, additives were added by adhering to the surface of electrophotographic toner, so the additives were easily peeled off, but with the above structure, the additives were incorporated into the surface of the granules. Since the toner is retained in the same shape, the retention strength is improved and functional deterioration of the electrophotographic toner due to exfoliation of the additive is reduced.

[0070] Therefore, since the fluidity of the electrophotographic toner can be improved and stabilized, the electrophotographic toner can be stably supplied to the copying machine, and therefore, the images obtained in the copying machine can also be stabilized. It has the effect of becoming something.

[0071] The electrophotographic toner according to claim 2 is obtained by mixing an additive that adds a function such as coloring with a granular material mainly containing a binder to obtain a mixture as described above; The mixture is suspended in hot air to melt the surface of the granules, and the additive is added to a predetermined position between the surface of the granules and the granules.

[0072] As a result, conventional electrophotographic toners are produced through a pulverization process, resulting in an amorphous shape and deterioration of the fluidity of the electrophotographic toner. However, with the above structure, the granules are Since the surface of the particles is once melted, the surface of the resulting electrophotographic toner becomes smoother, and the fluidity of the electrophotographic toner can be improved.

Furthermore, in the past, additives were added by adhering to the surface of electrophotographic toner, making it easy for the additives to peel off, but with the above structure, the additives were incorporated into the surface of the granules. Since the toner is retained in the same shape, the retention strength is improved and functional deterioration of the electrophotographic toner due to exfoliation of the additive is reduced.

As a result, it is possible to improve the fluidity of the electrophotographic toner and stabilize it, so that it is possible to stably supply the electrophotographic toner to the copying machine, and therefore, the images obtained in the copying machine can be improved. This also has the effect of making it stable.

As described above, the method for producing an electrophotographic toner according to claim 3 includes the step of obtaining a mixture by mixing an additive that adds a function such as coloring with a granular material mainly containing a binder. 1
and a second step of floating this mixture in hot air to melt the surface of the granules and adding the additive near the surface of the granules.

[0076] By suspending the mixture in hot air, it is possible to obtain an electrophotographic toner that incorporates and retains additives and has a smoother surface. Since it is possible to stably obtain an electrophotographic toner that can more stably perform the function of the agent, it is possible to obtain an electrophotographic toner that has excellent stability in images obtained in a copying machine.

The method for producing an electrophotographic toner according to claim 4, as described above, includes the step of mixing an additive that adds a function such as coloring with a granular material mainly containing a binder to obtain a mixture. 1
a second step of floating this mixture in hot air to melt the surface of the granules, and adding the additive from the surface of the granules to a predetermined position between the granules and the granules; This is a method of obtaining toner for electrophotography.

[0078] By suspending the mixture in hot air, it is possible to obtain an electrophotographic toner that incorporates and retains additives and has a smoother surface. Since it is possible to stably obtain an electrophotographic toner that can more strongly retain the function of the agent and stably exhibit its function, it is possible to obtain an electrophotographic toner that has excellent image stability when used in a copying machine. This effect is achieved.

The method for producing an electrophotographic toner according to claim 5 is as described above, by kneading, pulverizing, and classifying a colorant, a charge control agent, a release agent, and a binder to form granules having a predetermined particle size. The first step is to prepare the granules, the second step is to obtain a mixture by mixing the granules and a fluidizing agent, and the mixture is suspended in hot air to melt the surface of the granules. In this method, an electrophotographic toner is obtained by a third step of cooling and solidifying the surface and adding the fluidizing agent near the surface of the granules.

[0080] As a result, the surface of the electrophotographic toner obtained is smoother than before due to the surface treatment in hot air, so that the fluidity of the electrophotographic toner is improved. In addition, by surface treatment in hot air, the fluidizing agent is unevenly distributed on the toner surface and is distributed more evenly, so even if the amount added is smaller than before, the surface concentration of the fluidizing agent can be increased. It is possible to further improve fluidity.

As a result, by suspending the mixture in hot air, it is possible to stably obtain an electrophotographic toner with excellent fluidity. This has the effect that toner can be obtained.

The method for producing an electrophotographic toner according to claim 6 includes the steps of kneading, pulverizing, and classifying a colorant, a charge control agent, and a binder to prepare granules having a predetermined particle size. A second step is to mix the granules and a mold release agent to obtain a mixture, and to make the surface of the granules smooth by floating this mixture in hot air at a temperature that softens the mold release agent. In this method, an electrophotographic toner is obtained by a third step of

[0083] As a result, the surface of the electrophotographic toner obtained becomes smoother than before due to the surface treatment in hot air, and the fluidity of the electrophotographic toner is improved. In addition, by surface treatment in hot air, the release agent is unevenly distributed on the toner surface, and is distributed more evenly, so even if the amount added is smaller than before, the surface concentration of the release agent can be increased. It is possible to improve mold releasability.

As a result, by suspending the mixture in hot air, it is possible to stably obtain an electrophotographic toner with excellent fluidity and releasability, resulting in excellent stability of images obtained in copying machines. This has the effect that it is possible to obtain a toner for electrophotography.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a surface modification device showing an electrophotographic toner and a method for producing the same according to the present invention.

FIG. 2 is an explanatory diagram showing the state of additives in each electrophotographic toner manufactured by changing the temperature of hot air in the above manufacturing method.

[Explanation of symbols]

6 Hot air 7 Toner (electrophotographic toner) 11 Base particles (granules) 12 Additives

Claims (6)

[Claims] Claim 1: After obtaining a mixture by mixing an additive having a function such as coloring and a granular material mainly containing a binder, heating the mixture to melt the surface of the granular material, An electrophotographic toner, characterized in that the additive is added near the surface of the granular material. [Claim 2] After obtaining a mixture by mixing an additive that adds a function such as coloring and a granular material mainly containing a binder, the mixture is suspended in hot air to improve the surface of the granular material. melt and
An electrophotographic toner characterized in that the additive is added to a predetermined position between the surface of the granular body and the part included in the granular body. 3. A first step of obtaining a mixture by mixing an additive that adds a function such as coloring with a granular material mainly containing a binder;
A toner for electrophotography is obtained by a second step of floating the mixture in hot air to melt the surface of the granules and adding the additive near the surface of the granules. Toner manufacturing method. 4. A first step of obtaining a mixture by mixing an additive that adds a function such as coloring with a granular material mainly containing a binder;
A second step of floating this mixture in hot air to melt the surface of the granules and adding the additive from the surface of the granules to a predetermined position between the granules and the granules is carried out by electrophotography. 1. A method for producing toner for electrophotography, characterized by obtaining toner for use in electrophotography. 5. A first step of kneading, pulverizing, and classifying a colorant, a charge control agent, a mold release agent, and a binder to produce granules of a predetermined particle size; a second step of mixing to obtain a mixture; the mixture is suspended in hot air to melt the surface of the granules, and then the surface is cooled and solidified to spread the fluidizing agent onto the surface of the granules; A method for producing an electrophotographic toner, the method comprising: obtaining an electrophotographic toner by a third step of adding the electrophotographic toner to the surrounding area. 6. Kneading a colorant, a charge control agent, and a binder;
A first step of producing granules of a predetermined particle size by crushing and classifying, a second step of mixing the granules and a mold release agent to obtain a mixture, and a temperature at which the mixture is softened by the mold release agent. A method for producing an electrophotographic toner, characterized in that the electrophotographic toner is obtained by a third step of making the surface of the granules smooth by floating them in hot air.