JPH11282206A - Toner composition and production of toner using that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner compsn. and a producing method of a toner using using this compsn. SOLUTION: The toner compsn. contains monomers for formation of a binder resin, a coloring agent, a stabilizer, a charge controlling agent, a lubricant and a polymn. initiator. The stabilizer is obtd. by dispersing hydrophobic silica in a distilled water of which pH is controlled to 10 to 14 and then controlling the pH of the dispersed material to 6 to 8. By using the toner compsn. above described, a toner having an improved charge amt., average particle size and distribution characteristics of the particle size can be produced. Especially, when the toner compsn. contains a surfactant, the obtd. toner has extremely improved dispersibility of the coloring agent and the charge controlling agent. By using this toner, further improved image quality than conventional quality can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner composition and a method for producing a toner using the same. In particular, the present invention not only improves the dispersibility of the colorant but also improves the particle size characteristics and charge amount characteristics of the toner. The present invention relates to a composition for forming a toner and a method for producing a toner using the composition.

[0002]

2. Description of the Related Art Recently, the demand for printers has been gradually increasing with the development of the computer industry. As a result, the amount of toner used has increased. Toners used in the realization of images are mostly manufactured by the crushing method. In the method for producing a toner by a pulverization method, first, a polymer binding resin, a colorant, a charge control agent, and the like are mixed in a dry manner. Next, the mixture is melt-mixed and then cooled, and the resultant is pulverized to produce toner particles.

[0003] The toner produced by the above method has a wide particle size distribution. Therefore, toner particles outside the predetermined particle size range should be excluded, which is not desirable in terms of cost. Further, there is a problem that the resolution is inferior depending on the limit of dispersion of the charge control agent, the colorant and the like and the shape of the toner particles. In order to solve such problems, a method for producing spherical toner particles by a polymerization method has been proposed. The polymerization method is roughly classified into an emulsion polymerization method and a suspension polymerization method. However, according to the emulsion polymerization, since the particle size of the finally formed toner is too small (5 μm or less), it is harmful to the human body, and thus it is substantially difficult to apply to a printer. For this reason, a suspension polymerization method is preferred over an emulsion polymerization method.

A method for producing a toner by the above suspension polymerization method is as follows. Water is used as a reaction medium, and a polymerization reaction is performed by adding a monomer for forming a binding resin, a charge control agent, a stabilizer, a lubricant, and a colorant to the reaction medium. When the polymerization reaction is completed, spherical particles precipitate in the reaction mixture. The resulting particles are filtered and dried to obtain toner particles.

[0005] Phosphate or hydrophobic silica is used as the stabilizer. However, when a phosphate is used as a stabilizer, the particle size of the finally formed toner particles is too large (approximately 35 μm), so that the particle size distribution is not only wide from several μm to several hundred μm, but also the charge amount. Is poor in characteristics.
Therefore, it is not suitable for use as a toner. On the other hand, when hydrophobic silica is used as the stabilizer, the polymerization reaction itself is not performed because the hydrophobic silica is hardly dispersed in water. In order to solve such a problem, the hydrophobic silica must be dissolved in an organic solvent such as methanol before being mixed with the components constituting the toner composition in order to carry out the polymerization reaction.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to solve such problems as fillers such as charge control agents and colorants.
ller) It is an object of the present invention to provide a toner-forming composition having improved particle dispersibility and toner particle size characteristics. Another object of the present invention is to provide a method for producing a toner using the composition.

[0007]

According to the present invention, there is provided a toner composition comprising a binder resin-forming monomer, a colorant, a stabilizer, a charge control agent, a lubricant and a polymerization initiator. After dispersing the hydrophobic silica in distilled water adjusted to pH 10 to 14, the stabilizer has a pH of 6 to 14.
A toner composition characterized by being obtained by adjusting the toner composition to 8.

Another object of the present invention is to (a) adjust the pH of distilled water to 10 to 14 using a water-soluble base, and then disperse hydrophobic silica therein; and (b) adjust the pH of the mixture. Is adjusted to 6 to 8; and (c) a monomer for forming a binding resin, a polymerization initiator, a charge control agent, a lubricant, and a colorant are mixed, and the mixture is added to the mixture obtained in the step (b). Adding and mixing; (d) polymerizing the resulting product to form toner particles; and (e) removing foreign matter remaining on the surface of the toner particles. Of the manufacturing method.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The toner composition of the present invention is obtained by dispersing hydrophobic silica as a stabilizer in distilled water adjusted to pH 10 to 14, and then neutralizing the resultant to pH 6 to 8 to obtain a resulting product. It has its features to use. By adding and mixing a monomer for forming a binder resin, a colorant, a charge controlling agent, a lubricant and a polymerization initiator to such a stabilizer, each component is uniformly dispersed differently from a conventional toner composition. The obtained toner composition is obtained.

The mixing weight ratio between the binder resin forming monomer and the silica solid powder is preferably 50: 1 to 25: 1. Here, if the mixing ratio of the silica solid powder to the binder resin-forming monomer exceeds the above range, the recovery of the toner particles after the polymerization reaction is extremely difficult, and if the mixing ratio does not reach the above range, the toner particles are aggregated with each other. Not desirable.

[0011] The toner composition of the present invention may further contain an ionic surfactant. At this time, the ionic surfactant is not particularly limited, and both a cationic surfactant and an anionic surfactant can be used.

As the anionic surfactant, sodium laurylsulfate is used,
Cetyltrimethylammonium bromide is used as the cationic surfactant.
e) or cetyltrimethylammonium chloride (cet
yltrimethylammonium chloride). And
The mixing weight ratio of the binder resin-forming monomer to the surfactant is preferably from 1000: 1 to 2000: 1.
Here, when the mixing ratio of the surfactant to the monomer for forming the binding resin exceeds the above range, it is difficult to recover the toner particles. When the mixing ratio does not reach the above range, the dispersibility of the colorant is poor, which is not desirable.

As the binder resin-forming monomer of the present invention, any monomer commonly used in the production of a toner by a polymerization method can be used. In the present invention, styrene and butyl methacrylate are used, and the mixing weight ratio of the styrene and butyl methacrylate is 6: 4 to 9: 1, preferably 7: 3 to 8: 2. The charge control agent of the present invention is a substance that plays a role in controlling the charge of the toner, and any conventional charge control agent can be used. As the colorant of the present invention, black pigment carbon black is used.

The lubricant used in the present invention is a substance that improves the fluidity of the toner, and wax is used here. As the polymerization initiator, any ordinary polymerization initiator can be used. Hereinafter, a method for producing a toner using the toner composition according to the present invention will be described.

[0015] Distilled water is adjusted to pH 10 using a water-soluble base.
After adjusting to 14, hydrophobic silica is added and dispersed therein. Next, the pH of the mixture is adjusted to 6 to 8 to neutralize the mixture. Here, the water-soluble base is not particularly limited, and sodium hydroxide, potassium hydroxide, aqueous ammonia and the like can be used. The acid used when neutralizing the hydrophobic silica dispersion having a pH of 10 to 14 is not particularly limited, but it is preferable to use formic acid.

A mixture of a monomer for forming a binding resin, a charge controlling agent, a colorant, a lubricant, and a polymerization initiator is added to the reaction mixture and mixed well. In some cases, an ionic surfactant, particularly a cationic surfactant, may be further added to the mixture. It is desirable that such a mixing process proceeds with a ball mill.

Next, the resultant is polymerized in a nitrogen atmosphere. When the polymerization reaction is completed, unreacted substances are removed from the reaction mixture using methanol. Here, when the conversion rate of the polymerization reaction is low (70 to 80%), unreacted substances are removed using methanol, and when the conversion rate of the polymerization reaction is high (80% or more), unreacted substances are removed using distilled water. It is desirable to remove the substance.

Then, after filtering the obtained precipitate, foreign substances remaining on the surface of the precipitate are removed. A dilute potassium hydroxide aqueous solution or methanol is used in the foreign matter removing process. The resultant product from which the foreign matter has been removed is dried in a vacuum oven for a predetermined time to obtain toner particles according to the present invention. The average particle size of the toner obtained by the above method is 5 to 2
At 0 μm, the charge is −10 to −20 (μc / g) and the glass transition temperature is 60 to 75 ° C. Hereinafter, the present invention will be described in detail based on embodiments, but the present invention is not limited to only the following embodiments.

<Embodiment 1> Aqueous ammonia was added to 600 ml of distilled water to adjust the pH to about 10, and 6 g of hydrophobic silica R-972 (manufactured by Degu) was added thereto. (Homogenizer) 1 at 5000 rpm
Stirred for 0 minutes. Next, the resultant was neutralized with formic acid to prepare a first composition. 140 ml of styrene,
60 ml of butyl methacrylate, 4 g of 2,2-azobisisobutyronitrile, 6 g of carbon black 2350 (produced by Mitsubishi) (average particle size: 15 ml), Bontron S-3
4 2 g of Orient Chemical and 2 g of wax were mixed to prepare a second composition.

The mixture of the first composition and the second composition was stirred in a ball mill for 24 hours. Next, a polymerization reaction was carried out at 75 ° C. for 7 hours under a nitrogen atmosphere. After completion of the reaction, unreacted styrene and butyl methacrylate were removed from the reaction mixture using methanol. Next, the resultant was filtered and washed, and dried in a vacuum oven for 2 days to produce toner particles.

Embodiment 2 Toner particles were produced in the same manner as in Embodiment 1, except that the content of carbon black was 10 g.

Embodiment 3 Toner particles were manufactured in the same manner as in Embodiment 1, except that the first composition further contained 0.1 g of cetyltrimethylammonium bromide (CTAB).

Embodiment 4 Toner particles were manufactured in the same manner as in Embodiment 1, except that an aqueous solution of sodium hydroxide was used in place of aqueous ammonia at the time of manufacturing an aqueous solution of hydrophobic silica alkali.

<Embodiment 5> Instead of Mitsubishi's 2350 as carbon black, PRINTEX L- from Degu Corporation is used.
Except that 6 (average particle size: 18 ml) was used, toner particles were produced in the same manner as in Embodiment 1.

<Comparative Example 1> After mixing 400 ml of distilled water and 100 ml of methanol, the hydrophobic silica R
A first composition was prepared by dispersing 6 g of -972 (Deg). After mixing styrene (140 ml) and butyl methacrylate (60 ml) with distilled water (600 ml), 2,2-
Azobisisobutyronitrile 4 g, carbon black 6
g, Bontron S-34 2 g and wax 2 g were added and mixed to prepare a second composition.

After adding the second composition to the first composition, the reaction mixture is heated at 75 ° C. under a nitrogen atmosphere at 75 ° C.
Polymerized for hours. After completion of the reaction, unreacted styrene and butyl methacrylate were removed from the reaction mixture using methanol. Next, the resultant was filtered and washed, and dried in a vacuum oven for 2 days to produce toner particles.

Comparative Example 2 Toner particles were produced in the same manner as in Example 1, except that di-n-butylamine was used instead of aqueous ammonia during the production of the first composition.

Comparative Example 3 A first composition was prepared by adding 3 g of tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ : Yakuri Pure Chemical) to 600 ml of distilled water. Styrene 1
40 ml, butyl methacrylate 60 ml, 2,2-azobisisobutyronitrile 2 g, carbon black 235
No. 0 (manufactured by Mitsubishi), 2 g of Bontron S-34 (Oriental Chemical) and 2 g of wax were mixed to prepare a second composition.

After adding the second composition to the first composition, the mixture was mixed in a ball mill for 24 hours. Next, the mixture was subjected to a polymerization reaction at 75 ° C. for 7 hours under a nitrogen atmosphere. After completion of the reaction, unreacted styrene and butyl methacrylate were removed from the reaction mixture using methanol. Next, the resultant was filtered and washed, and dried in a vacuum oven for 2 days to produce toner particles.

Comparative Example 4 Toner particles were produced in the same manner as in Example 1, except that the first composition and the second composition were mixed with a high-speed stirrer. When toner particles were produced according to Comparative Example 1, the conversion of the polymerization reaction was very low, and it was difficult to obtain spherical toner particles after the polymerization reaction was completed. And the first using n-butylamine
When the composition was produced (Comparative Example 2), the polymerization reaction itself could not be carried out because the hydrophobic silica itself was aggregated and it was difficult to obtain the first composition having a uniform composition.

On the other hand, Embodiments 1 to 5 and Comparative Example 3
The characteristics of the toner particles produced in Example 4 were evaluated by the following methods. The particle size and particle size distribution of the toner particles are measured using a coulter counter and a laser particle sizer, and the surface analysis of the toner particles is performed using a scanning electron microscopy.
pe: SEM).

The dispersibility of the carbon black in the toner particles was measured using an optical microscope (Labon Photo-2 (Nikon).
The evaluation is made as follows using ABOPHOT-2)). ：: Carbon black is very finely dispersed ○: Carbon black is finely dispersed △: Large particles of carbon black are seen a little ×: Large particles of carbon black are seen a lot (Differential scann
ing calorimeter: measured by DSC, and the molecular weight is determined by gel permeation chromatography.
(graphy: GPC). The charge of toner particles is measured by a Toshiba blow-off meter.
Measure using

On the other hand, Embodiments 1 to 5 and Comparative Examples 3 to
The dispersibility, average particle size, glass transition temperature, and charge amount of carbon black were measured for the toner particles prepared in Example 4, and the results are shown in Table 1 below.

[0034]

[Table 1]

From Table 1 above, it was found that the toner particles produced according to Embodiments 1 to 5 had better carbon black dispersibility than those of Comparative Examples 3 and 4. In particular, the particle size of the toner particles produced according to Comparative Example 3 tended to be divided into 20 μm or more and 10 μm or less. Among them, the toner particles having a large particle diameter of 20 μm or more have a certain degree of dispersion of the pigment therein, but the toner particles having a small particle diameter of 10 μm or less have no inflow of the pigment therein. .

FIGS. 1 to 5 are optical micrographs of the toner particles manufactured according to the first to fifth embodiments. FIGS. 6 and 7 are optical micrographs of the toner particles manufactured according to the comparative examples 3 and 4. It is. Referring to FIGS. 1 to 5, it was found that the toner particles manufactured according to Embodiments 1 to 5 had very good dispersibility of carbon black as compared with Comparative Examples 3 and 4. Especially,
Referring to FIG. 3, when cetyltrimethylammonium bromide (CTAB) was added (Embodiment 3), it was found that carbon black was uniformly dispersed in the toner particles.

On the other hand, the particle size distribution characteristics of the toner particles produced according to Embodiments 1 to 5 and Comparative Examples 3 and 4 were examined and shown in FIGS. 8 to 14, it was found that the particle size distribution characteristics of the toner particles manufactured according to Embodiments 1 to 5 were improved as compared with the toner particles manufactured according to Comparative Examples 3 and 4. In addition, Table 1 shows that the toner particles manufactured according to Embodiments 1 to 5 have improved charge amount and average particle size characteristics of the toner particles as compared with Comparative Examples 3 and 4.

[0038]

By using the toner composition of the present invention, a toner having improved charge, average particle size and particle size distribution characteristics can be produced. In particular, when the toner composition contains a surfactant, a toner in which the dispersibility of the colorant and the charge control agent is greatly improved can be obtained, and the use of such a toner results in improved image quality compared to the conventional toner. Can be

[Brief description of the drawings]

FIG. 1 is an optical micrograph of toner particles produced according to Embodiment 1 of the present invention.

FIG. 2 is an optical micrograph of toner particles manufactured according to Embodiment 2 of the present invention.

FIG. 3 is an optical micrograph of toner particles manufactured according to Embodiment 3 of the present invention.

FIG. 4 is an optical micrograph of toner particles manufactured according to Embodiment 4 of the present invention.

FIG. 5 is an optical micrograph of toner particles manufactured according to Embodiment 5 of the present invention.

FIG. 6 is an optical micrograph of toner particles manufactured according to Comparative Example 3 of the present invention.

FIG. 7 is an optical micrograph of toner particles manufactured according to Comparative Example 4 of the present invention.

FIG. 8 is a view showing a particle size distribution characteristic of toner particles manufactured according to the first embodiment of the present invention.

FIG. 9 is a view showing a particle size distribution characteristic of toner particles manufactured according to Embodiment 2 of the present invention.

FIG. 10 is a view showing a particle size distribution characteristic of toner particles manufactured according to Embodiment 3 of the present invention.

FIG. 11 is a view showing a particle size distribution characteristic of toner particles manufactured according to Embodiment 4 of the present invention.

FIG. 12 is a view showing a particle size distribution characteristic of toner particles manufactured according to Embodiment 5 of the present invention.

FIG. 13 is a graph showing the particle size distribution characteristics of toner particles manufactured according to Comparative Example 3 of the present invention.

FIG. 14 is a view showing a particle size distribution characteristic of toner particles manufactured according to Comparative Example 4 of the present invention.

Claims (11)

[Claims] 1. A toner composition comprising a monomer for forming a binding resin, a colorant, a stabilizer, a charge control agent, a lubricant and a polymerization initiator, wherein the stabilizer is hydrophobic in distilled water adjusted to pH 10-14. A toner composition obtained by adjusting pH to 6 to 8 after dispersing a functional silica. 2. The toner composition according to claim 1, wherein the mixing weight ratio of the binder resin forming monomer and the silica solid powder is 50: 1 to 25: 1. 3. The toner composition according to claim 1, further comprising an ionic surfactant. 4. A mixing weight ratio of the monomer for forming a binding resin and the ionic surfactant is from 1,000: 1 to 200.
4. The toner composition according to claim 3, wherein the ratio is 0: 1. 5. The toner composition according to claim 3, wherein the ionic surfactant is selected from the group consisting of sodium lauryl sulfate, cetyltrimethylammonium bromide and cetyltrimethylammonium chloride. 6. A step of (a) adjusting the pH of distilled water to 10 to 14 using a water-soluble base and dispersing hydrophobic silica therein, and (b) adjusting the pH of the mixture to 6 to 8. (C) mixing a monomer for forming a binding resin, a polymerization initiator, a charge controlling agent, a lubricant, and a colorant, and then adding and mixing the mixture to the mixture obtained in the step (b). And (d) polymerizing the resulting product to form toner particles; and (e) removing foreign matter remaining on the surface of the toner particles. 7. The method of claim 6, wherein said water-soluble base is selected from the group consisting of aqueous ammonia, sodium hydroxide and potassium hydroxide. 8. The method according to claim 6, wherein a mixing weight ratio of the binder resin forming monomer and the silica solid powder is 15: 1 to 25: 1. 9. The method according to claim 1, wherein the mixing of the monomer for forming the binding resin, the polymerization initiator, the charge controlling agent, the lubricant and the colorant in the step (c) is performed by further adding an ionic surfactant. 7. The method of claim 6, wherein 10. The method of claim 9, wherein said ionic surfactant is selected from the group consisting of sodium lauryl sulfate, cetyltrimethylammonium bromide and cetyltrimethylammonium chloride. 11. The mixing weight ratio of the binder resin-forming monomer to the ionic surfactant is from 1000: 1 to 200.
The method of claim 9, wherein the ratio is 0: 1.