KR20150080287A - Toner and method of preparing the same - Google Patents

Abstract

Disclosed are a toner and a manufacturing method thereof. The disclosed toner comprises: a core unit including first wax having a melting point of MP_1 and a weight average molecular weight of Mw_1, and a first binder resin; a first shell unit including second wax having a melting point of MP_2 and a weight average molecular weight of Mw_2, and a second binder resin and surrounding the core unit; and a second shell unit including a third binder resin and surrounding the first shell unit, wherein at least one selected from a group comprising the core unit, the first shell unit and the second shell unit contain a coloring agent, and each of the MP1, the MP_2, the Mw_1 and the Mw_2 satisfies respective equation MP_1 < MP_2 and equation Mw_1 < Mw_2.

Description

Toner and method of preparing same

A toner and a manufacturing method thereof are disclosed. More particularly, the present invention relates to a triple structure toner having improved surface characteristics and excellent environmental stability, and a process for producing the same.

Generally, the toner is prepared by adding a coloring agent, wax, or the like to a thermoplastic resin serving as a binder resin. It is also possible to use a charge control agent which imparts chargeability to the toner and keeps it, a release agent such as a wax for releasing the toner from the fixing portion of the image forming apparatus, a toner for improving fluidity and developability, Can be added to the toner. Examples of the method for producing such a toner include a physical method such as a pulverization method and a chemical method such as a suspension polymerization method, an emulsion aggregation method, a chemical milling method, and a dispersion polymerization method.

Among them, the emulsion aggregation method (see U.S. Patent No. 5,916,725, No. 6,268,103, etc.) includes a step of preparing a fine emulsion resin particle composition through emulsion polymerization, and a step of coagulating the composition with a colorant etc. in a separate dispersion do. This method has an advantage in that it can solve problems such as a high cost and a wide particle size distribution in the pulverization method, and can make the toner particles spherical by controlling the coagulation condition.

However, toner particles produced by the conventional emulsion agglomeration method have a problem in that a part of the wax is protruded to the surface of the toner, thereby deteriorating the surface characteristics and environmental stability of the toner.

One embodiment of the present invention provides a triple structure toner having improved surface properties and excellent environmental stability.

Another embodiment of the present invention provides a method of producing the toner.

According to an aspect of the present invention,

A core portion comprising a first wax having a melting point of MP ₁ and a weight average molecular weight of Mw ₁ and a first binder resin;

A second wax and a second binder resin having a melting point of MP ₂ and a weight average molecular weight of Mw ₂ , the first shell portion surrounding the core portion; And

And a second shell portion surrounding the first shell portion,

At least one portion selected from the group consisting of the core portion, the first shell portion and the second shell portion further comprises a coloring agent,

The MP ₁ , the MP ₂ , the Mw _1, and the Mw ₂ satisfy a formula (MP ₁ <MP ₂ ) and a formula (Mw ₁ <Mw ₂ ), respectively.

The first shell part may further include the first wax.

MP ₁ and Mw ₁ may be 70 to 76 ° C and 800 to 1,500, respectively, and MP ₂ and Mw ₂ may be 85 to 93 ° C and 2,900 to 3,600, respectively.

The content of the first wax and the content of the second wax are 4 to 15 parts by weight and 1 to 4 parts by weight, respectively, based on 100 parts by weight of the total content of the first binder resin, the second binder resin and the third binder resin Can be.

The first binder resin, the second binder resin and the third binder resin may independently have a weight average molecular weight of 24,000 to 79,000.

The toner may include 70 to 90 parts by weight of the first binder resin: second binder resin: third binder resin: 5 to 25 parts by weight: 1 to 6 parts by weight.

According to another aspect of the present invention,

(S10) of injecting a first binder resin dispersion liquid, a first wax dispersion liquid and a coagulant into a reactor, and then raising the contents of the reactor first to form a toner core portion;

(S20) forming a first shell part surrounding the toner core part by further adding a second binder resin dispersion and a second wax dispersion to the reactor contents containing the toner core part;

(S30) forming a second shell portion surrounding the first shell portion by further adding a third binder resin dispersion to the reactor contents containing the first shell portion; And

And a step (S40) of obtaining the combined toner particles by secondarily raising the contents of the reactor through the second shell part forming step,

In the step (S10) and the step (S20), the colorant dispersion is further introduced into the reactor,

Wherein a melting point (MP ₁ ) and a weight average molecular weight (Mw ₁ ) of the first wax contained in the first wax dispersion and a melting point (MP ₂ ) and a weight average molecular weight (Mw ₂ ) satisfy the expressions (MP ₁ <MP ₂ ) and the expressions (Mw ₁ <Mw ₂ ), respectively.

The primary heating may be performed at a temperature lower by 2 to 20 ° C than the glass transition temperature of the first binder resin injected into the core forming step.

The secondary heating may be performed at a temperature 10-40 ° C higher than the glass transition temperature of the third binder resin added to the second shell forming step.

The content of the first wax added to the core part forming step (S10) and the content of the second wax added to the first shell part forming step (S20) may be the same as those of the first binder resin, 4 to 15 parts by weight and 1 to 4 parts by weight with respect to 100 parts by weight of the total amount of the third binder resin.

The content of the first binder resin added to the core forming step (S10), the content of the second binder resin added to the first shell forming step (S20), and the second shell forming step (S30) The content of the third binder resin added may be 70 to 90 parts by weight, 5 to 25 parts by weight and 1 to 6 parts by weight, respectively.

According to the method for producing a toner according to an embodiment of the present invention, it is possible to obtain a triple structure toner excellent in fixability, releasability and glossiness, and improved in surface characteristics and excellent in environmental stability.

FIG. 1A is a schematic view of a toner according to an embodiment of the present invention, showing a state after completion of an aggregation process. FIG.
FIG. 1B is a schematic view of a toner according to an embodiment of the present invention, which is a view after completion of the coalescing process. FIG.
FIG. 2A is a schematic view of a conventional toner, which shows the state after completion of the coagulation process. FIG.
FIG. 2B is a schematic view of a conventional toner, which shows a state after completion of the coalescing process. FIG.

Hereinafter, a toner according to an embodiment of the present invention and a method for producing the same will be described in detail.

The toner according to an embodiment of the present invention includes a core portion including a first wax having a melting point of MP ₁ and a weight average molecular weight of Mw ₁ and a first binder resin, a core portion having a melting point of MP ₂ and a weight average molecular weight of Mw ₂ A first shell portion including a second wax and a second binder resin and surrounding the core portion, and a second shell portion including a third binder resin and surrounding the first shell portion. As used herein, the term &quot; toner &quot; may refer to one toner particle according to the context, and may refer to a collection of toner particles (i.e., toner powder).

The at least one portion selected from the group consisting of the core portion, the first shell portion, and the second shell portion further includes a colorant.

The MP ₁ , the MP ₂ , the Mw _1, and the Mw ₂ may each satisfy the following formulas:

MP ₁ < MP ₂ ,

Mw ₁ < Mw ₂ .

The first shell part may further include the first wax.

The first wax lowers the fixation temperature of the toner and improves the gloss. In addition, the first wax is disposed only within the core portion and optionally the first shell portion, and is not disposed within the second shell portion, so that hot offset does not occur during use of the toner.

The second wax is disposed in the first shell part, which is an intermediate layer, so that when the toner is used, the second shell part ruptures and improves the releasability of the toner.

If the second shell part is too thick, the fixing property and releasability of the toner deteriorate. To prevent this, the second shell part may have the form of a thin film.

MP ₁ and Mw ₁ may be 70 to 76 ° C and 800 to 1,500, respectively. When the MP ₁ and the Mw ₁ are within the above ranges, the fixation temperature of the toner can be lowered and the gloss can be improved while preventing hot offset during use of the toner.

MP ₂ and Mw ₂ may be 85 to 93 ° C and 2,900 to 3,600, respectively. When MP ₂ and Mw ₂ are within the above ranges, the fixability and releasability of the toner can be kept high.

The content of the first wax and the content of the second wax are 4 to 15 parts by weight and 1 to 4 parts by weight, respectively, based on 100 parts by weight of the total content of the first binder resin, the second binder resin and the third binder resin Can be. When the content of the first wax and the content of the second wax are within the above ranges, the releasability of the toner can be kept high while the fixation temperature of the toner is lowered and the gloss is improved.

The first binder resin, the second binder resin and the third binder resin may independently have a weight average molecular weight of 24,000 to 79,000.

The toner may include 70 to 90 parts by weight of the first binder resin: second binder resin: third binder resin: 5 to 25 parts by weight: 1 to 6 parts by weight. When the content ratio of each of the above-mentioned binder resins is within the above-mentioned range, releasability of the toner can be improved while keeping the low temperature fixing property and gloss of the toner at a high level.

The toner not only has excellent low-temperature fixation properties, glossiness and releasability but also has excellent environmental stability because the second shell part as the outermost layer does not contain wax and the surface characteristics of the toner are improved. In the present specification, &quot; surface properties of toner &quot; means the characteristics of a toner having a smooth surface without irregularities, and &quot; environmental stability of the toner &quot; means that even if left in an environment of high temperature and high humidity and low temperature and humidity for a long time, The ability of the toner to maintain the properties of the toner.

Hereinafter, the structure of the toner will be described in more detail with reference to FIGS. 1A and 1B.

FIG. 1A is a schematic view of a toner 10 according to an embodiment of the present invention, and FIG. 1B is a schematic diagram of a toner 10 according to an embodiment of the present invention, showing the completion of the coalescing process.

1A and 1B, a toner 10 includes a core portion 11, a first shell portion 12 surrounding the core portion 11, a second shell portion 13 surrounding the first shell portion 12, .

1A showing the toner 10 after completion of the coagulation process, the first wax W11 and the first binder resin (not shown) are distributed in the core portion 11 and the first wax W11 and the first binder resin The second wax W12 and the second binder resin (not shown) are distributed, and the third binder resin (not shown) is distributed in the second shell portion 13. [

1B showing the toner 10 after completion of the coalescing process, the first wax W11a and the first binder resin (not shown) are distributed in the core portion 11 and the first wax W11a and the first binder resin The first binder resin (not shown) is distributed in addition to the second wax W12 and the second binder resin (not shown), and the third binder resin (not shown) is distributed in the second shell portion 13. [ The reason why the first wax W11b is distributed in the first shell part 12 in the toner 10 of FIG. 1B is as follows. That is, as shown in FIG. 1A, in the process of coalescence process proceeds in accordance with the first wax portion (W11b) of the (W11) which was in the MP that has a _first and a low value because the Mw ₁ hayeotgi moved to the first shell part (12). In addition, as shown in Figure 1a, the aggregation process completed later in the process of coalescence process proceeds in accordance with the having a first wax (W11) that is the MP ₁ and the Mw ₁ low value was in the core portion 11 (See W11a and W11b in Fig. 1B).

As shown in Figs. 1A and 1B, the first wax (W11 = W11a + W11b) and the second wax W12 are not present in the second shell portion 13 at all after the completion of the coagulation process and the completion of the coalescing process . That is, a part W11a of the first wax W11 remains in the core part 11 and the remaining part W11b moves only from the core part 11 to the first shell part 12. The second wax W12 Remains in the first shell part 12 without moving to the other part.

A colorant (not shown) may be further distributed to at least one portion selected from the group consisting of the core portion 11, the first shell portion 12, and the second shell portion 13. [

An external additive (not shown) may be further distributed on the surface of the second shell portion 13.

Hereinafter, for comparison with the toner according to an embodiment of the present invention, a conventional toner will be described in detail with reference to FIGS. 2A and 2B.

2A is a schematic view of a conventional toner 20 after completion of the coagulation process, and FIG. 2B is a schematic view of a conventional toner 20, showing the completion of the coalescing process.

Referring to FIGS. 2A and 2B, the toner 20 includes a core portion 21 and a shell portion 22 surrounding the core portion 21.

2A showing the toner 20 after completion of the coagulation process, the wax W21 and the third binder resin (not shown) are distributed to the core portion 21 and the fourth binder resin Not shown).

The third binder resin and the fourth binder resin may be the same as the first binder resin, the second binder resin or the third binder resin, independently of each other.

A colorant (not shown) may be further distributed to at least one of the core portion 21 and the shell portion 22.

An external additive (not shown) may be further distributed on the surface of the shell portion 22.

2B showing the toner 20 after completion of the coalescing process, the wax W21a and the third binder resin (not shown) are distributed to the core portion 21 and the shell portion 22 is provided with the fourth binding In addition to the resin (not shown), wax W12b is further distributed. The reason why the wax W21b exists in the shell portion 22 in the toner 20 of Fig. 2B is that a part of the wax W21 in the core portion 21 after completion of the coagulation process And moved to the shell portion 22 in the course of the coalescing process. 2A, after completion of the coagulation process, the wax W21 in the core portion 21 is deformed and deformed (see W21a and W21b in FIG. 2B) in the course of the merging process.

A part of the wax W21 is moved from the core portion 21 to the shell portion 22 and the wax W21b is applied to the shell portion 22 after the completion of the coalescing process, Lt; / RTI &gt; As a result, the conventional toner 20 has a problem that the surface characteristics are degraded and the environmental stability is poor.

Hereinafter, a method of manufacturing a toner according to an embodiment of the present invention will be described in detail.

The method for producing a toner according to the present invention comprises the steps of charging a first binder resin dispersion liquid, a first wax dispersion liquid and a coagulant into a reactor and then raising the temperature of the reactor first to form a toner core (S10) (S20) of adding a second binder resin dispersion liquid and a second wax dispersion liquid to the first shell portion to form a first shell portion surrounding the toner core portion, adding a third binder resin dispersion to the reactor contents containing the first shell portion (S30) forming a second shell part surrounding the first shell part, and obtaining the combined toner particles by secondary heating the reactor contents through the second shell part forming step (S40). Each of the above steps may be performed in one reactor, but the present invention is not limited thereto. One or more of the four steps and two or more steps may be performed in two or more reactors.

The colorant dispersion may be further added to the reactor in at least one of the step (S10) and the step (S20).

Wherein a melting point (MP ₁ ) and a weight average molecular weight (Mw ₁ ) of the first wax contained in the first wax dispersion and a melting point (MP ₂ ) and a weight average molecular weight (Mw ₂ ) satisfy the following equations respectively:

MP ₁ < MP ₂ ,

Mw ₁ < Mw ₂ .

The MP ₁ , MP ₂ , Mw ₁ and Mw ₂ above may be respectively the same as those described in the portion of the toner.

The reactor may comprise a stirrer, a heating means (e.g. a heater), a pressurizing means and / or a depressurizing means (e. G., A vacuum line and a vacuum pump).

In one embodiment, the binder resin dispersion, the colorant dispersion, and the wax dispersion may be the same or similar to the latex dispersion, colorant dispersion, and wax dispersion described in Korean Patent Publication No. 2010-0048071. Korean Patent Publication No. 2010-0048071 is incorporated herein by reference.

In another embodiment, the binder resin dispersion, the colorant dispersion, and the wax dispersion may be the same or similar to the polyester resin dispersion, colorant dispersion, and wax dispersion disclosed in Korean Patent Publication No. 2010-0115148 . Korean Patent Publication No. 2010-0115148 is incorporated herein by reference in its entirety.

The first binder resin contained in the first binder resin dispersion, the second binder resin contained in the second binder resin dispersion, and the third binder resin included in the third binder resin dispersion may be the same as those described in the toner portion Each may be the same.

The glass transition temperature of the first binder resin, the glass transition temperature of the second binder resin, and the glass transition temperature of the third binder resin may be independently from each other 54 to 65 ° C. When the glass transition temperature of each of the binder resins is within the above range, the toner formed using the binder resin particles is excellent in fixing property.

The colorant to be used in the preparation of the colorant dispersion may be black pigments, cyan pigments, magenta pigments, yellow pigments, and mixtures thereof, which are pigments commonly used commercially.

The total amount of the colorant added to the step (S10) and the step (S20) may be 3 to 20 parts by weight based on 100 parts by weight of the total amount of the first binder resin, the second binder resin and the third binder resin have.

Each wax used in the preparation of each wax dispersion may be a known wax. Natural waxes such as carnauba wax and rice wax; Synthetic waxes such as polypropylene wax and polyethylene wax; Petroleum waxes such as montan wax; Alcohol wax; And an ester-based wax. The wax may be used alone or in combination of two or more.

Further, each of the waxes may include at least one of a paraffin wax and a polyester wax. The paraffin wax mainly contains C ₂₀ to C ₃₆ linear saturated hydrocarbons, and may have a weight average molecular weight of 30 to 500 and a melting point of 40 to 80 ° C.

The coagulant may be added not only to the core forming step (S10) but also to the first shell forming step (S20) and / or the second shell forming step (S30). As such coagulant, Fe-polysilicate such as NaCl, KCl, or PSI (Poly Silicato Iron) may be used.

The total amount of the flocculant added to the step (S10), the step (S20) and the step (S20) is preferably at most about 100 parts by weight based on 100 parts by weight of the total amount of the first binder resin, the second binder resin and the third binder resin 5 to 40 parts by weight.

The content of the first wax added to the step (S10) and the content of the second wax to be added to the step (S20) are determined so that the total content of the first binder resin, the second binder resin and the third binder resin 4 to 15 parts by weight and 1 to 4 parts by weight, respectively, based on 100 parts by weight of the polymer.

The primary temperature elevation may proceed to a temperature 2 to 20 ° C lower than the glass transition temperature (Tg ₁ ) of the first binder resin injected into the core portion forming step (S 10). The temperature during the first temperature increase the range _{(Tg 1 - 2 ~ 20 ℃} ) is within, causing a flocculation picked by each particle.

The step (S10) (that is, the coagulation step by the first temperature increase) may proceed until the particle size of the toner becomes 5.0 to 6.0 mu m.

The secondary heating may be performed at a temperature 10-40 ° C higher than the glass transition temperature (Tg ₃ ) of the third binder resin added to the second shell part forming step (S30). If the temperature at the time of the second heating is within the above range (Tg ₃ + 10 to 40 ° C), it is possible to prevent the wax masses from sticking together to form a wax mass, and then protruding the wax mass to the toner surface.

The step (S40) (i.e., the step of coalescing by the second heating) may proceed until the particle diameter of the toner becomes 6.6 to 7.2 mu m, whereby toner particles having substantially uniform particle size and shape can be obtained.

Each of the binder resins used in the above steps may be the same kind of binder resin.

The content of the first binder resin added to the core forming step (S10), the content of the second binder resin added to the first shell forming step (S20), and the second shell forming step (S30) The content of the third binder resin added may be 70 to 90 parts by weight, 5 to 25 parts by weight and 1 to 6 parts by weight, respectively. When the content ratio of the binder resin used in each of the above steps is within the above range, a toner excellent in fixing property and excellent in toner strength and durability can be obtained.

The method of manufacturing the toner may further include washing and drying the toner particles obtained in the combining step with water. First, the reactor contents containing the toner particles are cooled to room temperature, filtered, the filtrate is removed, and the toner particles are washed with water. Pure water having a conductivity of 10 uS / cm or less may be used for the washing, and the washing may be continued until the conductivity of the filtered filtrate becomes 50 uS / cm or less. Cleaning of the toner with pure water may proceed batchwise or continuously. Cleaning of the toner using pure water can be performed to remove unnecessary components other than toner components such as impurities that may affect the chargeability of the toner and unnecessary coagulants that do not participate in aggregation.

The toner obtained after the washing step can be dried by using a fluid bed dryer, a flash jet dryer or the like. Further, a desired external additive can be added to the toner obtained by drying. The external additive is for improving the fluidity of the toner or controlling the charging property. Examples of the external additive include large diameter silica (particle diameter:? 40 nm), small particle size silica (7 nm? Particle diameter? 30 nm), polymer beads, Mixtures may be used.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these embodiments.

Example

Manufacturing example  One: Binder resin  Preparation of dispersion

A reactor having a volume of 30 liters equipped with a stirrer, a thermometer and a condenser was installed in an oil bath. 6,600 g and 32 g of distilled water and a surfactant (Dowfax 2A1) were charged into the thus-installed reactor, respectively, and the temperature of the reactor was increased to 70 ° C and stirred at a stirring speed of 100 rpm. Thereafter, the monomer, that is, 8,380 g of styrene, 3,220 g of butyl acrylate, 370 g of 2-carboxyethyl acrylate, 226 g of 1,10-decanediol diacrylate, 5,075 g of distilled water, 226 g of a surfactant (Dowfax 2A1) 530 g of polyethylene glycol ethyl ether methacrylate and 188 g of 1-dodecanethiol as a chain transfer agent were stirred with a disk type impeller at 450 rpm for 30 minutes, and then slowly added to the reactor for 1 hour. Thereafter, the reaction was allowed to proceed for about 8 hours and then slowly cooled to room temperature (25 ° C) to complete the reaction. As a result, a binder resin was obtained.

After completion of the reaction, the glass transition temperature (Tg) of the binder resin obtained above was measured using a differential scanning calorimeter (DSC), and as a result, the temperature was 57 ° C. The weight average molecular weight of the binder resin was measured by GPC (gel permeation chromatography) using a polystyrene standard sample, and the weight average molecular weight was 45,000.

Manufacturing example  2: Preparation of colorant dispersion

540 g of cyan pigment (ECB303, manufactured by Dainippon Ink & Chemicals, Inc.), 27 g of a surfactant (Dowfax 2A1) and 2,450 g of distilled water were placed in a reactor having a volume of 5 liters equipped with a stirrer, a thermometer and a condenser, Respectively. After performing the preliminary dispersion for 10 hours, it was dispersed for 4 hours using a bead mill (Zeta RS, Netzsch, Germany). As a result, a colorant dispersion was obtained.

After completion of the dispersion, the particle size of the cyan pigment particles was measured using Multisizer 2000 (manufactured by Malvern), and the D50 (v) was found to be 170 nm. Here, D50 (v) means a particle size corresponding to 50% based on the volume average particle diameter, that is, a particle size corresponding to 50% of the total volume when accumulating the volume from the small particle by measuring the particle diameter.

Manufacturing example  3-1: Preparation of wax dispersion (A)

65 g of a surfactant (Dowfax 2A1) and 1,935 g of distilled water were put into a 5-liter reactor equipped with a stirrer, a thermometer and a condenser, and the mixture was stirred at 95 ° C for about 2 hours with stirring to obtain a wax (P- 212, MP = 73 ° C, Mw = 1,150) was charged into the reactor. The mixed solution was dispersed for 30 minutes using a pressure discharge type homogenizer (Nihon Precision Machinery). As a result, a wax dispersion was obtained.

After completion of the dispersion, the particle size of the dispersed wax particles was measured using Multisizer 2000 (manufactured by Malvern), and the D50 (v) was found to be 200 nm.

Manufacturing example  3-2: Preparation of wax dispersion (B)

65 g of a surfactant (Dowfax 2A1) and 1,935 g of distilled water were put into a 5-liter reactor equipped with a stirrer, a thermometer and a condenser, and the mixture was stirred at 95 ° C for about 2 hours with stirring to obtain a wax (P- 787, MP = 89 占 폚, Mw = 3,250) was charged into the reactor. The mixed solution was dispersed for 30 minutes using a pressure discharge type homogenizer (Nihon Precision Machinery). As a result, a wax dispersion was obtained.

After completion of the dispersion, the particle size of the dispersed wax particles was measured using Multisizer 2000 (manufactured by Malvern), and the D50 (v) was found to be 200 nm.

Example  1: Preparation of toner particles of core-first shell-second shell structure

(Core part forming step)

The binder resin dispersion prepared in Preparation Example 1, the colorant dispersion prepared in Preparation Example 2 and the wax dispersion (A) prepared in Production Example 3-1 were placed in a 70-liter reactor, and the mixture was stirred at 25 ° C for about 15 minutes And the mixture was stirred at a stirring speed of 1.21 m / sec. A mixed solution (PSI / nitric acid aqueous solution = 1/2 (weight ratio)) of PSI (Poly Silcato Iron) and an aqueous nitric acid solution (concentration = 1.88 wt%) was added as a coagulant to the mixture and homogenized (IKA, 50) at 25 DEG C at a stirring rate of 10,000 rpm for 30 minutes. At this time, the pH of the contents of the reactor was 1.6. Thereafter, the temperature of the reactor was elevated to 53 캜 for the first time, and the mixture was stirred at 140 rpm to continue aggregation until the D50 (v) of the toner particles became 5.3 탆

(First cell formation step)

After the core portion forming step, the binder resin dispersion prepared in Preparation Example 1 and the wax dispersion (B) prepared in Production Example 3-2 were added to the reactor over 30 minutes. Thereafter, agitation was continued by stirring at a stirring speed of 120 rpm until the D50 (v) of the toner particles became 6.3 탆 while maintaining the temperature of the reactor at 53 캜.

(Second shell portion forming step)

After the first shell part forming step, the binder resin dispersion prepared in Preparation Example 1 was added to the reactor over a period of 20 minutes. Subsequently, stirring was continued until the D50 (v) of the toner particles became 6.8 占 퐉 while maintaining the temperature of the reactor at 53 占 폚.

(Subsequent step)

After the second shell part formation step, a 4 wt% sodium hydroxide aqueous solution was added to the reactor, and the mixture was stirred at 115 rpm until the pH reached 4. When the pH was 7, the mixture was stirred at 100 rpm. Thereafter, the temperature of the reactor was elevated to 96 캜 while maintaining the stirring speed, so that the toner particles were allowed to coalesce. Thereafter, when the circularity was measured using FPIA-3000 (manufactured by Sysmex, Japan), when the measured circularity was 0.980, the temperature of the reactor was cooled to 40 ° C and the pH of the reactor contents was adjusted to 9.0 The separated toner particles were washed four times with distilled water and then mixed with an aqueous nitric acid solution of 1.88 wt% in distilled water to prepare a toner having a pH of 1.5 , And then washed with distilled water four times to remove all of the surfactant and the like. Thereafter, the washed toner particles were dried in a fluid bed drier at a temperature of 40 캜 for 5 hours to obtain dried toner particles.

Comparative Example  1: Preparation of toner particles of core-shell structure

(Core part forming step)

The binder resin dispersion prepared in Preparation Example 1, the colorant dispersion prepared in Preparation Example 2 and the wax dispersion (A) prepared in Production Example 3-1 were placed in a 70-liter reactor, and the mixture was stirred at 25 ° C for about 15 minutes And the mixture was stirred at a stirring speed of 1.21 m / sec. A mixed solution (PSI / nitric acid aqueous solution = 1/2 (weight ratio)) of PSI (Poly Silcato Iron) and an aqueous nitric acid solution (concentration = 1.88 wt%) was added as a coagulant to the mixture and homogenized (IKA, 50) at 25 DEG C at a stirring rate of 10,000 rpm for 30 minutes. At this time, the pH of the contents of the reactor was 1.6. Thereafter, the temperature of the reactor was elevated to 53 캜 for the first time, and the mixture was stirred at 140 rpm to continue aggregation until the D50 (v) of the toner particles became 5.3 탆

(Cell formation step)

After the core portion forming step, the binder resin dispersion prepared in Preparation Example 1 was added to the reactor over 30 minutes. Thereafter, stirring was continued until the D50 (v) of the toner particles became 6.8 탆 while maintaining the temperature of the reactor at 53 캜.

(Subsequent step)

After the shell part formation step, a 4 wt% sodium hydroxide aqueous solution was added to the reactor, and the mixture was stirred at 115 rpm until the pH reached 4. The mixture was stirred at 100 rpm until the pH reached 7. Thereafter, the temperature of the reactor was elevated to 96 캜 while maintaining the stirring speed, so that the toner particles were allowed to coalesce. Thereafter, when the circularity was measured using FPIA-3000 (manufactured by Sysmex, Japan), when the measured circularity was 0.980, the temperature of the reactor was cooled to 40 ° C and the pH of the reactor contents was adjusted to 9.0 The separated toner particles were washed four times with distilled water and then mixed with an aqueous nitric acid solution of 1.88 wt% in distilled water to prepare a toner having a pH of 1.5 , And then washed with distilled water four times to remove all of the surfactant and the like. Thereafter, the washed toner particles were dried in a fluid bed drier at a temperature of 40 캜 for 5 hours to obtain dried toner particles.

The contents of the components used in Example 1 and Comparative Example 1 are shown in Table 1 below.

Binder resin dispersion (A) (g) Colorant dispersion (g) Wax dispersion (A) (g) Wax dispersion (B) (g) Coagulant (g) Example 1 Step of forming core part 8,380 670 619 0 3,820 The first shell part forming step 2,910 0 0 241 0 The second shell part forming step 270 0 0 0 0 Comparative Example 1 Step of forming core part 8,380 670 860 0 3820 Shell part formation step 3,180 0 0 0 0

The toner particles Volume average particle diameter ( D50 (v)) measurement

The volume average particle size (D50 (v)) of the toner particles was measured using a Multisizer (TM) 3 Coulter Counter ( ^R ) from Beckman Coulter Inc. In the above multisizer, an appropriate amount of a surfactant (Dowfax 2A1) was added to 50-100 ml of an ISOTON-II electrolyte (Beckman Coulter Co.) using an aperture of 100 탆, and 10 to 15 mg of a test sample And dispersed in an ultrasonic disperser for 5 minutes to prepare a sample.

Measurement of circularity of toner particles

The circularity of the toner particles was measured using FPIA-3000 (manufactured by Sysmex, Japan). In the roundness measurement using FPIA-3000, a measurement sample was prepared by adding a proper amount of a surfactant (Dowfax 2A1) to 50 to 100 ml of distilled water, adding 10 to 20 mg of toner particles thereto, and dispersing the dispersion in an ultrasonic disperser for 1 minute .

The circularity is automatically obtained from FPIA-3000 by the following equation (1).

[Equation 1]

Circularity = 2 占 (area 占 π) ^1/2 / perimeter

In the above equation, the area means the area of the projected toner, and the perimeter means the circumferential length of the projected toner. This value can have a value from 0 to 1, and the closer to 1, the more spherical.

Evaluation example

The content of the surface wax, the fixability, the fixing temperature range, the gloss and the image quality of each of the toners prepared in Example 1 and Comparative Example 1 were evaluated as follows, and the results are shown in Table 2 below.

(Evaluation of the ratio of surface wax)

The surface of each toner was analyzed by TOF-SIMS (product of ION-TOF GmbH), and the content ratio (% by weight) of the surface wax to the total content of wax contained in each toner was measured.

(Evaluation of fixing property and fixing temperature range)

- Equipment: belt type fuser

- Unfixed images for test: 100% pattern

- Test temperature: 120 ~ 200 ℃

- Speed: 160 mm / sec

- Dwell time: 0.08 sec

(TG 810G; manufactured by Cabot) and 2 g of titania (JMT150FI; Tayca) prepared in Example 1 and Comparative Example 1, To output a 2 cm x 2 cm solid pattern to the HP CP1215 printer to collect unfixed images. Then, the fixability of the unfixed image was evaluated while changing the temperature of the fixing roller in a fixing tester modified so that the fixing temperature could be arbitrarily changed. The OD (Optical Density) of each fixed image was measured using spectroeye spectrophotometer (GretagMacbeth), and the 810 tape of 3M company was attached to the fixation image area. The resultant was moved back and forth five times with 500 g of spindle, OD was measured again. The fixability was calculated by the following formula (2).

&Quot; (2) &quot;

Fixability (%) = [(OD after tape removal) / (OD before tape removal)] * 100

The fixing temperature range in which the fixing property was 90% or more without regard to cold offset or hot offset was regarded as the fixation temperature range of the toner. That is, the fixing temperature range of the toner is the following MFT to HOT.

- Minimum Fusing Temperature (MFT): Minimum temperature at which fixability is 90% or higher without cold offset

- HOT (Hot Offset Temperature): The fixability is 90% or more, but the lowest temperature at which hot offset occurs

(Gloss evaluation)

- Equipment: belt type fuser

- Unfixed images for test: 100% pattern

- Test temperature: 160 ℃

- Speed: 160 mm / sec

- Dwell time: 0.08 sec

(TG 810G; manufactured by Cabot) and 2 g of titania (JMT150FI; Tayca) prepared in Example 1 and Comparative Example 1, To output a 2 cm x 2 cm solid pattern to the HP CP1215 printer to collect unfixed images. Then, the temperature of the fixing roller was set at 160 占 폚 in the fixing tester modified so that the fixing temperature could be arbitrarily changed, and the unfixed image was fixed. As a result, a fixed image was obtained. Thereafter, the glossiness of the toner was measured using a gloss meter (GretagMacbeth, Glossmeter).

- Measuring angle: 60 degrees (°)

(Image quality evaluation)

(TG 810G; manufactured by Cabot) and 2 g of titania (JMT150FI; Tayca) were used to prepare HP A toner image was output from the CP1215 printer to evaluate the image quality on the basis of the following criteria.

- ○: The detail of the image is clearly visible

- Δ: slightly outdated

- ×: Image detail is broken

The ratio of surface wax (wt%) Fixability
(%) Fusing temperature range
(° C) Glossiness Image quality Example 1 3.12 97 140 ~ 200 14 ○ Comparative Example 1 6.74 95 150 ~ 180 12 ○

Referring to Table 1, the toner prepared in Example 1 exhibited a lower ratio of surface wax than the toner prepared in Comparative Example 1, indicating excellent surface properties and environmental stability. In addition, the toner prepared in Example 1 showed a wider fixing temperature range than the toner prepared in Comparative Example 1, and showed excellent low-temperature fixability. In addition, the toner prepared in Example 1 was found to have the same level of fixability, glossiness, and image quality as the toner prepared in Comparative Example 1.

Although the present invention has been described with reference to the drawings and embodiments, it is to be understood that various changes and modifications may be suggested to those skilled in the art. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10, 20: toner 11, 21: core part
12: first shell part 13: second shell part
22: Shell part

Claims (11)

A core portion comprising a first wax having a melting point of MP ₁ and a weight average molecular weight of Mw ₁ and a first binder resin;
A second wax and a second binder resin having a melting point of MP ₂ and a weight average molecular weight of Mw ₂ , the first shell portion surrounding the core portion; And
And a second shell portion surrounding the first shell portion,
At least one portion selected from the group consisting of the core portion, the first shell portion and the second shell portion further comprises a coloring agent,
Wherein MP ₁ , MP ₂ , Mw _1, and Mw ₂ satisfy the following formulas:
MP ₁ < MP ₂ ,
Mw ₁ < Mw ₂ . The method according to claim 1,
Wherein the first shell part further comprises the first wax. The method according to claim 1,
Wherein MP ₁ and Mw ₁ are 70 to 76 ° C and 800 to 1,500, respectively, and MP ₂ and Mw ₂ are 85 to 93 ° C and 2,900 to 3,600, respectively. The method according to claim 1,
The content of the first wax and the content of the second wax are 4 to 15 parts by weight and 1 to 4 parts by weight, respectively, based on 100 parts by weight of the total content of the first binder resin, the second binder resin and the third binder resin Wife Toner. The method according to claim 1,
Wherein the first binder resin, the second binder resin, and the third binder resin independently have a weight average molecular weight of 24,000 to 79,000. The method according to claim 1,
Wherein the toner comprises 70 to 90 parts by weight of the first binder resin: second binder resin: third binder resin: 5 to 25 parts by weight: 1 to 6 parts by weight. (S10) of injecting a first binder resin dispersion liquid, a first wax dispersion liquid and a coagulant into a reactor, and then raising the contents of the reactor first to form a toner core portion;
(S20) forming a first shell part surrounding the toner core part by further adding a second binder resin dispersion and a second wax dispersion to the reactor contents containing the toner core part;
(S30) forming a second shell portion surrounding the first shell portion by further adding a third binder resin dispersion to the reactor contents containing the first shell portion; And
And a step (S40) of obtaining the combined toner particles by secondarily raising the contents of the reactor through the second shell part forming step,
In the step (S10) and the step (S20), the colorant dispersion is further introduced into the reactor,
Wherein a melting point (MP ₁ ) and a weight average molecular weight (Mw ₁ ) of the first wax contained in the first wax dispersion and a melting point (MP ₂ ) and a weight average molecular weight (Mw ₂ ) respectively satisfy the following formulas:
MP ₁ < MP _{2 ,}
Mw ₁ < Mw ₂ . 8. The method of claim 7,
Wherein the primary temperature elevation progresses to a temperature 2 to 20 占 폚 lower than a glass transition temperature of the first binder resin injected into the core portion forming step. 8. The method of claim 7,
Wherein the secondary increase in temperature progresses to a temperature 10 to 40 캜 higher than a glass transition temperature of the third binder resin added to the second shell part forming step. 8. The method of claim 7,
The content of the first wax added to the core part forming step (S10) and the content of the second wax added to the first shell part forming step (S20) may be the same as those of the first binder resin, 4 to 15 parts by weight and 1 to 4 parts by weight with respect to 100 parts by weight of the total content of the third binder resin. 8. The method of claim 7,
The content of the first binder resin added to the core forming step (S10), the content of the second binder resin added to the first shell forming step (S20), and the second shell forming step (S30) Wherein the content of the third binder resin added is 70 to 90 parts by weight, 5 to 25 parts by weight and 1 to 6 parts by weight, respectively.

Images