KR100409080B1 - Toner composition having high transfer efficiency and a method for preparing the same - Google Patents

Abstract

The present invention relates to a high transfer efficiency nonmagnetic one-component toner composition and a method of manufacturing the same, and more particularly, toner base particles comprising a) i) a binder resin and ii) a colorant; And b) an externally charged charge control agent having a particle diameter of 5 μm or less on the surface of the toner base particles, and a method for manufacturing the same.

The toner composition of the present invention has a high charge efficiency because of its narrow charge distribution, high chargeability and improved charge retention and charge exchangeability.

Description

High transfer efficiency toner composition and manufacturing method therefor {TONER COMPOSITION HAVING HIGH TRANSFER EFFICIENCY AND A METHOD FOR PREPARING THE SAME}

The present invention relates to a high transfer efficiency color toner composition and a method of manufacturing the same, and more particularly, to a nonmagnetic one-component toner composition in which a charge control agent is added to the surface of the toner base particles, and a method of manufacturing the same.

Color toners, which are increasing in demand in the field of electrophotographic technology in recent years, are manufactured by kneading pulverization, suspension polymerization, emulsion polymerization, and the like. Among these production methods, from the viewpoint of production stability productivity and the like, a kneading grinding method is mainly employed.

The kneading pulverization method refers to manufacturing a toner by cooling and pulverizing a mixture obtained by melt kneading a mixture of toner raw materials such as a binder resin, a colorant, a charge control agent, a mold release agent, and then pulverizing it into toner particles having a desired particle size. . The developing toner is developed by the triboelectric charging method and retains positive or negative charges depending on the polarity of the developed electrostatic latent image. The charging performance of the toner can be secured to a certain extent by the binder resin and the colorant, which are main components of the nonmagnetic one-component toner, but are not sufficient.

If the charging characteristics of the toner are not sufficient, a phenomenon such as a defect in image characteristics such as background contamination of the image or a decrease in image density, or a decrease in the life of hardware due to scattering or the like occurs. Therefore, there is a need to solve this problem through the use of charge control agents.

In the method of kneading the binder resin and the charge control agent like the kneading pulverization method, it is difficult to uniformly disperse the charge control agent, so that the charge control agent is likely to exist as aggregates in the toner particles. In addition, when it is pulverized, it becomes liable to crack at the interface of the aggregate, and as a result, the charge control agent is present on the toner surface by the pulverization. Therefore, although the charging speed is high, the charge distribution is widened because the amount of the charge control agent on the surface of the toner particles is different, and the content of the charge control agent in the toner becomes different due to poor dispersion, resulting in poor charge exchangeability and charge retention. Has a problem.

Here, by controlling the distribution of the charge control agent on the surface of the toner, it is possible to eliminate the uneven charging between the toner particles and obtain stable charging. In this way, a large amount of the charge control agent is present on the surface of the toner, and the toner The state where the charging characteristic between particles is nonuniform is small. Therefore, the charge distribution becomes sharp. However, if only the internal additives are used, the charge control agent inside the toner becomes more dominant, and the charge distribution is different between the toner particles, so that there remains a problem in maintaining charge exchangeability or charging characteristics.

Further, the method of controlling the distribution of the charge control component inside the toner, eliminating the uneven charging state between the toner particles, and obtaining stable charging, eliminates the influence of aggregates of the charge control agent inside the toner, and toner particles on the surface. What is necessary is to remove the nonuniform distribution of the charge control agent of liver. The method of incorporating a charge control agent into the toner alone is insufficient to develop a toner having the characteristics shown in the toner, that is, the charge distribution is narrow, high chargeability, and good charge retention and charge exchangeability.

Therefore, there is a demand for a toner having a narrow charge distribution, high chargeability, and good charge retention and charge exchangeability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the present inventors have found that the above object can be achieved by improving the amount and distribution of the charge control component present in the toner particle surface layer. .

Accordingly, an object of the present invention is to provide a one-component magnetic toner composition having a narrow charge distribution, high chargeability, and good charge retention and charge exchangeability.

It is also an object of the present invention to provide a method for producing a one-component magnetic toner composition having a narrow charge distribution, high chargeability, and good charge retention and charge exchangeability.

In order to achieve the above object, the present invention

a) i) binder resin; And

ii) colorants

Toner base particles comprising a; And

b) an externally charged charge control agent having a particle diameter of 5 μm or less on the surface of the toner base particles;

It provides a nonmagnetic one-component toner composition comprising a.

In addition, the present invention

a) i) binder resin; And

ii) colorants

Melting, kneading, pulverizing and classifying the same to prepare toner base particles; And

b) adding a charge control agent to the surface of the toner base particles

It provides a method for producing a nonmagnetic one-component toner composition comprising a.

Hereinafter, the present invention will be described in detail.

The present inventors have focused on the relationship between the presence state of the charge control agent in the toner surface and the inside of the toner, and the charge performance, charge exchangeability, and charge retention properties of the toner. It was found that it was influenced by the charge control agent on the surface layer and that the effect of the charge control agent inside the toner was not large. Also, when there were many charge control agents on the surface of the toner particles, it was excellent in charge exchangeability and high charge performance. However, when many charge control agents exist inside the toner particles, it has been found that the charge retention is poor, the charge exchangeability is insufficient, the chargeability is low, and in particular, the charging speed is slowed. Accordingly, it has been found that the object of the present invention can be achieved by improving the amount and distribution of the charge control component present in the toner particle surface layer.

The present invention relates to a dry toner for electrostatic charge image development containing at least a binder resin and a colorant as essential components, wherein a charge control agent is added to the outside.

That is, the toner of the present invention is obtained by adding a charge control agent from the outside to a dry toner for electrostatic charge image development containing at least a binder resin and a colorant as essential components. Such toner improves the dispersibility of the charge control agent on the surface of the toner particles as compared with the internal addition of the charge control agent, the non-uniform state of the internal charge control component between the toner particles, and the charge control component on the toner particle surface layer. It is possible to eliminate the concentration of, and by externalizing the charge control agent, it is possible to reduce the uneven state of the charge control component of the toner particle surface layer.

Examples of the charge control agent externally added in the present invention include azo metal complexes of chromium, metal salicylic acid complexes, organic chromium-containing dyes and quaternary ammonium salts. The addition amount is preferably in the range of 0.3 to 5 parts by weight, more preferably in the range of 0.5 to 3 parts by weight with respect to 100 parts by weight of the toner base particles. Moreover, 5 micrometers or less are preferable, and, as for the particle diameter, 3 micrometers or less are more preferable. If the amount of externally charged charging agent is less than 0.3 part by weight, it is difficult to see the effect of uniform charging property, and if it exceeds 5 parts by weight, too much charge control agent may adversely affect fixing failure or image contamination. It does not meet the object of the present invention. Therefore, the amount of the charge control agent added is preferably in the range of 0.3 to 5 parts by weight. In addition, when the size of the particles of the charge control agent exceeds 5 µm, the particle size is too large and the adhesion of the toner particles to the surface is inferior. Therefore, the size of the charge control agent used is suitably 5 μm or less.

In the present invention, when the charge control agent is externally attached, it is found that there is no significant difference as a result of comparing the case where the charge control agent is included with the toner base particles with and without the charge control agent. It can be seen that only the charge control agent on the surface can act as a charge control agent.

Although the charge control agent may be electrostatically attached to the surface of the toner particles, it is preferable that the charge control agent is fused by fusing or heating after fixing by mechanical mixing treatment such as Henschel mixer or hybridizer.

The toner composition to which the charge control agent of the present invention is added includes a binder resin and a colorant as essential components.

Examples of the binder resin include styrenes such as styrene, chloro styrene and vinyl styrene; olefins such as ethylene, propylene, butylene and isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate; methyl acrylate and ethyl acrylate. Methylene aliphatic carboxylic acid esters such as butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and dodecyl methacrylate; vinyl methyl ether, vinyl ethyl ether, Vinyl ethers such as vinyl butyl ether; homopolymers or copolymers such as vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, and the like, and particularly representative binder resins include polystyrene and styrene alkyl acrylate copolymers. , Styrene Methacrylic Acid Alkyl Copolymer, Styrene Acrylic A nitrile may be mentioned copolymers, styrene butadiene copolymers, styrene-maleic anhydride copolymer, polyethylene, polypropylene or the like. Polyesters, polyurethanes, epoxy resins, silicone resins, polyamides, modified rosins, paraffins and the like can also be used.

Examples of the colorant include carbon black, magnetic powder, dyes and pigments such as nigurosine dye, aniline blue, chacoyl blue, chrome yellow, ultramarine blue, dupont oil red, methylene blue chloride, phthalocyanine blue, lamp black, Rose Bengal, CI Pigment Red 48: 1, CI Pigment Red 122, C.I. Pigment Red 57: 1, C.I. Pigment Yellow 97, C.I. Pigment Yellow 12, C.I. Pigment Blue 15: 1, C.I. Pigment Blue 15: 3 and the like can be exemplified.

In addition, in the present invention, the toner is subjected to hydrophobic treatment such as hexamethyldisilazane, dimethyl dichlorosilane, octyl trimethoxy silane, etc. SiO ₂ , TiO ₂ , MgO, Al ₂ O ₃ , MnO, ZnO, Fe ₂ Addition of inorganic oxide fine particles such as O ₃ , CaO, BaSO ₄ , CeO ₂ , K ₂ O, Na ₂ O, ZrO ₂ , CaOSiO, K2O (TiO ₂ ) n, Al ₂ O ₃ · 2SiO ₂ as a flow promoter It may also include a release agent.

The average particle diameter of the toner of the present invention is preferably 25 µm or less, particularly in the range of 3 to 20 µm.

As described above, a toner having high chargeability, charge retention and charge exchangeability can be manufactured by externally adding a charge control agent, but the image is stably imaged even in an indirect transfer method which is more environmentally friendly and widely used according to the recent colorization trend. In order to realize this, a high transfer efficiency toner is required, and the production of such a high transfer efficiency toner is not enough by external addition of a charge control agent. In this invention, in order to improve such a part, the metal salt fatty acid generally used as a mold release agent was added, and the adhesive force with a drum was reduced, and the high transfer efficiency toner was manufactured.

The fatty acid which comprises the said metal salt fatty acid is a C4-C40 natural or synthetic fatty acid, and any of saturated unsaturated may be sufficient, and a hydroxyl group, an aldehyde group, and an epoxy group may exist in a structure. Examples of such fatty acids include capuroic acid, capuric acid, capuric acid, lauric acid, myristic acid, millylake oleic acid, parmitic acid, palmito oleic acid, stearic acid, oleic acid, linolenic acid, arachinic acid, behenic acid , Elkaic acid, montenic acid, isostearic acid, epoxy stearic acid and the like can be used one or two or more. Stearic acid is particularly preferred.

Examples of the metal of the metal salt fatty acid include various metals such as zinc, iron, copper, cadmium, aluminum, calcium, magnesium, nickel, cobalt, manganese, lithium, and barium. The addition amount of the metal salt fatty acid to be used is suitably about 0.1 to 3 parts by weight, more preferably 0.5 to 2.5 parts by weight based on 100 parts by weight of the toner base particles. If the external amount is less than 0.1 parts by weight, the effect of reducing the adhesion to the drum is insignificant, and the transfer efficiency does not increase. If the external amount exceeds 3 parts by weight, the scattering increases, and fog (background) occurs.

As for the particle size of the said metal stearic acid, 1-4 micrometers or less are suitable. If the particle diameter of the metal salt fatty acid is more than 4㎛, it is not effective to reduce adhesion to the drum due to poor adhesion to the toner base particles, so it is not effective to improve the transfer efficiency, and if it is less than 1㎛, the scattering increases. fog (background) phenomenon occurs.

Although the toner of the present invention can be used according to a dry process, in general, after forming an electrostatic latent image on a drum such as an electrophotographic or an electrostatic recording, the electrostatic latent image is visualized by a developer in a developer to transfer a visible image. After that, it is possible to use in the process of cleaning the toner remaining on the drum.

Hereinafter, although an Example and a comparative example demonstrate this invention in order to demonstrate the effect of this invention, this invention is not limited to this. In addition, the numbers indicating the formulation and the like are parts by weight.

EXAMPLE

Toner Base Particle Manufacturing

Polyester resin (molecular weight: 2.5 × 10 ⁵ ) 94 wt%

Phthalocyanine P.BI. 15: 3 5% by weight

1% by weight of low molecular weight polypropylene

Each raw material was mixed by the Henschel mixer by the above formulation, melt kneaded at a temperature of 165 ° C. in a twin-screw melt kneader, finely ground in a jet mill grinder, and then classified in a wind classifier to obtain a volume average particle diameter of 9.2 μm. Toner base particles were obtained.

Attachment of Charge Control Agents and Metal Salt Fatty Acids

The types of charge control agent and metal stearic acid to be attached to the toner base particles are shown in Tables 1 and 2, respectively.

TABLE 1

Charge control agent Average particle size (㎛) Kinds Remarks Charge control agent A 1-3 Metal complex Negative Charge control agent B 6-9 Metal complex Negative Charge control agent C 10-30 Metal complex Negative Charge control agent D 15-20 Non- metal Negative

TABLE 2

Metal stearic acid Average particle size (㎛) Metal Stearic Acid A 0.3-0.6 Metal Stearic Acid B 1.2-2.5 Metal Stearic Acid C 3.2-4.9 Metal Stearic Acid D 5.9-6.8

Charge control agents and metal salt fatty acids having different average particle diameters with respect to 100 parts by weight of the toner base particles were stirred and mixed for 5 minutes using a Henschel mixer for 5 parts by weight as shown in Table 3 below, and adhered to the toner base particles. A non-magnetic single component toner of the present invention of -12 was prepared, and a comparative toner of Comparative Examples 1-24 was prepared.

TABLE 3

Charge control agent (parts by weight) Metal salt fatty acids (parts, parts by weight) Example 1 Charge control agent A, 0.3 Metal Salt Fatty Acids B, 0.3 Example 2 Charge control agent A, 0.3 Metal Salt Fatty Acids B, 1.0 Example 3 Charge control agent A, 0.3 Metal Salt Fatty Acids B, 3.0 Example 4 Charge control agent A, 1.0 Metal Salt Fatty Acids B, 0.3 Example 5 Charge control agent A, 1.0 Metal Salt Fatty Acids B, 1.0 Example 6 Charge control agent A, 1.0 Metal Salt Fatty Acids B, 3.0 Example 7 Charge control agent A, 3.0 Metal Salt Fatty Acids B, 0.5 Example 8 Charge control agent A, 3.0 Metal Salt Fatty Acids B, 1.0 Example 9 Charge control agent A, 3.0 Metal Salt Fatty Acids B, 3.0 Example 10 Charge control agent A, 5.0 Metal Salt Fatty Acids B, 0.5 Example 11 Charge control agent A, 5.0 Metal Salt Fatty Acids B, 1.0 Example 12 Charge control agent A, 5.0 Metal Salt Fatty Acids B, 3.0 Comparative Example 1 Charge control agent B, 1.0 Metal Salt Fatty Acids A, 1.0 Comparative Example 2 Charge control agent B, 1.0 Metal Salt Fatty Acids B, 1.0 Comparative Example 3 Charge control agent B, 1.0 Metal Salt Fatty Acids C, 1.0 Comparative Example 4 Charge control agent B, 1.0 Metal Salt Fatty Acids D, 1.0 Comparative Example 5 Charge control agent C, 1.0 Metal Salt Fatty Acids A, 1.0 Comparative Example 6 Charge control agent C, 1.0 Metal Salt Fatty Acids B, 1.0 Comparative Example 7 Charge control agent C, 1.0 Metal Salt Fatty Acids C, 1.0 Comparative Example 8 Charge control agent C, 1.0 Metal Salt Fatty Acids D, 1.0 Comparative Example 9 Charge control agent D, 1.0 Metal Salt Fatty Acids A, 1.0 Comparative Example 10 Charge control agent D, 1.0 Metal Salt Fatty Acids B, 1.0 Comparative Example 11 Charge control agent D, 1.0 Metal Salt Fatty Acids C, 1.0 Comparative Example 12 Charge control agent D, 1.0 Metal Salt Fatty Acids D, 1.0 Comparative Example 13 Charge control agent A, 1.0 - Comparative Example 14 - Metal Salt Fatty Acids B, 1.0 Comparative Example 15 Charge control agent B, 0.1 Metal Salt Fatty Acids B, 1.0 Comparative Example 16 Charge control agent C, 0.1 Metal Salt Fatty Acids B, 1.0 Comparative Example 17 Charge control agent D, 0.1 Metal Salt Fatty Acids B, 1.0 Comparative Example 18 Charge control agent B, 6.0 Metal Salt Fatty Acids B, 1.0 Comparative Example 19 Charge control agent A, 1.0 Metal Salt Fatty Acids B, 4.0 Comparative Example 20 Charge control agent A, 1.0 Metal Salt Fatty Acids A, 0.1 Comparative Example 21 Charge control agent A, 1.0 Metal Salt Fatty Acids B, 4.0 Comparative Example 22 Charge control agent A, 1.0 Metal salt fatty acids C, 0.1 Comparative Example 23 Charge control agent A, 1.0 Metal Salt Fatty Acids D, 4.0 Comparative Example 24 Charge control agent A, 6.0 Metal Salt Fatty Acids B, 1.0

Next, each of the toners was printed up to 5000 sheets under normal temperature and humidity (20 ° C, 55% RH) using a commercially available non-magnetic one-component printer (phaser 740 manufactured by Tektronix) composed of a contact developing device. And the evaluation results are shown in Table 4.

TABLE 4

Image density (I.D) Fog (background) Transfer efficiency (%) Example 1 1.35 △ B Example 2 1.38 O B Example 3 1.42 O B Example 4 1.49 O A Example 5 1.52 O A Example 6 1.45 △ A Example 7 1.45 O B Example 8 1.44 O B Example 9 1.49 O B Example 10 1.39 O A Example 11 1.37 △ B Example 12 1.38 O B Comparative Example 1 1.25 X D Comparative Example 2 1.29 △ D Comparative Example 3 1.30 △ D Comparative Example 4 1.28 △ D Comparative Example 5 1.25 X D Comparative Example 6 1.22 X D Comparative Example 7 1.28 X D Comparative Example 8 1.25 X D Comparative Example 9 1.10 X E Comparative Example 10 1.17 △ E Comparative Example 11 1.20 △ E Comparative Example 12 1.19 △ E Comparative Example 13 1.15 X E Comparative Example 14 0.98 X F Comparative Example 15 1.20 △ D Comparative Example 16 1.25 △ D Comparative Example 17 1.20 △ D Comparative Example 18 1.25 X C Comparative Example 19 1.25 △ C Comparative Example 20 1.23 X D Comparative Example 21 1.26 X D Comparative Example 22 1.22 X C Comparative Example 23 1.26 △ C Comparative Example 24 1.22 X C

In Table 4, image density (ID) was measured using a Macbeth reflection densitometer RD918 solid area image (ID can be used if the value is 1.30 or more), and the fog (background) phenomenon of the image is determined by the optical microscope It was measured and evaluated visually.

O: The fog (background) phenomenon of the image is not confirmed.

(Triangle | delta): The fog (background) phenomenon of an image is partially confirmed.

X: The fog (background) phenomenon of the image is clearly confirmed.

In addition, the transfer efficiency is calculated by calculating the net consumption of the toner transferred to paper by printing up to 5000 sheets and subtracting the waste amount from each 500 sheets.

A: Over 90% of transfer efficiency

B: 80 ~ 90% transfer efficiency

C: Transfer efficiency 70 ~ 80%

D: Transfer efficiency 60 ~ 70%

E: Transfer efficiency 50 ~ 60%

F: below 50% of transfer efficiency

As can be seen from the results of Table 4, the nonmagnetic one-component developing toner of Examples 1 to 12 of the present invention having the charge control agent and the metal salt fatty acid adhered to the surface has a sufficient blackness with an image density (ID) of 1.30 or more. In addition, there was also a small amount of fog (background) of the image, so that there was no problem in use. In addition, in terms of transfer efficiency, it exhibited sufficient high transfer efficiency, so there was no problem in the indirect transfer method, and there was no problem in use in environmental problems or cartridge maintenance. On the other hand, in the nonmagnetic toners of Comparative Examples 1 to 24, in which the average particle diameter and the addition amount of the charge control agent and the metal salt fatty acid are not within the scope of the present invention, not only the image contamination and the fog (background) are too severe, but also various evaluation results. It is confirmed that there is a problem in using the cartridge because the transfer efficiency is low and the waste comes out a lot, which shortens the life of the cartridge and causes environmental problems.

As described above, according to the present invention, it is possible to obtain a high transfer efficiency toner having high chargeability, excellent charge retention, and uniform charge distribution, which does not cause problems such as image contamination even in long-term use. In addition, a stable image can be obtained, and there is no problem even in the indirect transfer method, and a uniform image can be obtained without any problems in terms of environmental problems or cartridge retention.

Claims (18)

a) i) binder resin; And ii) colorants Toner base particles comprising a; And b) an externally charged charge control agent having a particle diameter of 5 μm or less on the surface of the toner base particles; Nonmagnetic one-component toner composition comprising a. The nonmagnetic one-component toner composition according to claim 1, wherein the charge control agent is selected from the group consisting of a chromium azo metal complex, a salicylic acid metal complex, a chromium organic dye, and a quaternary ammonium salt. The nonmagnetic one-component toner composition according to claim 1, wherein the charge control agent is added in an amount of 0.3 to 5 parts by weight based on 100 parts by weight of the toner base particles. delete The nonmagnetic one-component toner composition according to claim 1, wherein a metal salt fatty acid is further added to the surface of the toner base particles. The fatty acid according to claim 5, wherein the fatty acid is caproic acid, caprylic acid, capuric acid, lauric acid, myristic acid, milistic oleic acid, parmitic acid, palmito oleic acid, stearic acid, oleic acid, linolenic acid, arachidic acid, bebe A nonmagnetic one-component toner composition, characterized in that it is selected from the group consisting of henic acid, elcaic acid, montenic acid, isostearic acid, epoxy stearic acid, and mixtures thereof. 6. The nonmagnetic one-component toner composition according to claim 5, wherein the metal salt fatty acid is added in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the toner base particles. 6. The nonmagnetic one-component toner composition according to claim 5, wherein the metal salt fatty acid has a particle size of 1 to 4 mu m. The nonmagnetic one-component toner composition according to claim 1, wherein the charging agent is fixed by mechanical mixing of a Henschel mixer or a hybridizer. The method of claim 1, wherein the binder resin is a styrene, olefin, vinyl ester, carboxylic acid ester, vinyl ether, homopolymer or copolymer of vinyl ketone, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin And paraffin. The nonmagnetic one-component toner composition according to claim 1, wherein the non-magnetic toner composition is selected from the group consisting of paraffins. The method of claim 1, wherein the colorant is carbon black, magnetic powder, nigurosine dye, aniline blue, carcoyl blue, chrome yellow, ultramarine blue, Dupont oil red, methylene blue chloride, phthalocyanine blue, lamp black, rose bengal, CI Pigment Red 48: 1, C.I. Pigment Red 122, C.I. Pigment Red 57: 1. C.I. Pigment Yellow 97, C.I. A nonmagnetic one-component toner composition selected from the group consisting of pigment yellow 12, C.I. pigment blue 15: 1 and C.I. pigment blue 15: 3. a) i) binder resin; And ii) colorants Melting, kneading, pulverizing and classifying the same to prepare toner base particles; And b) adding an externally charged charge control agent having a particle diameter of 5 μm or less on the surface of the toner base particles; Method for producing a nonmagnetic one-component toner composition comprising a. 13. The method according to claim 12, wherein the charge control agent is selected from the group consisting of a chromium azo metal complex, a metal salicylic acid complex, a chromium organic dye, and a quaternary ammonium salt. 13. The method according to claim 12, wherein the charge control agent is added in an amount of 0.3 to 5 parts by weight based on 100 parts by weight of the toner base particles. delete 13. The method of claim 12, further comprising adding a metal salt fatty acid to the surface of the toner base particles. 17. The method of claim 16, wherein the metal salt fatty acid is added in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the toner base particles. The method according to claim 16, wherein the metal salt fatty acid has a particle diameter of 1 to 4 mu m.