KR20100052873A - Preparation method of electrostatics image developing toner having the improved gloss and low fixing temperature properties - Google Patents

Abstract

The present invention relates to a method for producing an electrostatic charge image developing toner, wherein two kinds of polyester resins having different softening point bands (difference in softening point of 10 to 70 ° C) are used as binder resin during melt kneading of toner raw materials. At the same time, by specifically setting temperature gradient conditions in the melt kneading apparatus, not only are excellent gloss, low temperature fixability, anti-offset and dispersibility, but also improved fusion / deposition properties. It has the advantage of being able to produce the toner that represents.

Description

Preparation Method of Electrostatics Image Developing Toner Having the Improved Gloss and Low Fixing Temperature Properties}

The present invention relates to a method for producing a toner for developing electrostatic images. More specifically, the present invention uses two kinds of polyester resins having different softening point zones as binder resins during the melt kneading process of the raw material for toner production, and at the same time, specifically sets the temperature gradient conditions in the melt kneading apparatus to give gloss. The present invention relates to a process for producing a toner for electrostatic image development that not only has excellent gloss, low temperature fixability, anti-offset and dispersibility, but also exhibits improved fusion / deposition.

In general, the electrostatic charge image developing toner is melt-kneaded with an additive such as a colorant, a charge control agent, an inorganic filler, and the like together with a binder resin to obtain a mixed dough, pulverizing and classifying it, and toner particles obtained therefrom. It is manufactured through the external process which attaches a fluidity improver, a charge stabilizer, etc.

The toner obtained through the above process is subjected to the following process in the image developing apparatus.

(1) an exposure step of forming a latent electrostatic image by exposing a surface of a photosensitive drum charged with uniform charge through a charging step using static electricity;

(2) a developing step of obtaining a toner image by supplying toner to the electrostatic latent image,

(3) A fixing step of transferring and fixing a toner image fixed on the photosensitive drum surface by applying transfer heat and pressure on a transfer object.

On the other hand, the residual toner remaining on the surface of the photosensitive drum is removed and cleaned during the cleaning step.

In recent years, toners having improved anti-offset and charging stability along with low temperature fixing along with improvement of an image forming apparatus have been demanded. Furthermore, storage stability is required along with glossiness and durability of the toner after fixing to obtain a high quality image.

The toner is generally known to have the greatest influence on the physical properties of the binder resin, and therefore, a polyester resin is widely used as the binder resin material for the toner. In addition, polyolefin resins such as styrene resins, acrylic resins, styrene-acrylic resins, polyethylene or polypropylene resins, polyamide resins, polyurethane resins, polycarbonate resins, and copolymers or condensates thereof are studied. Various proposals are made according to the conditions of use.

Among them, there is an increasing demand for resins having transparency for forming images of high quality, and for this purpose, various manufacturing techniques using polyester resins as binder resins suitable for the above-described needs have been examined.

In the prior art, although the low softening point polyester resin according to the low molecular weight is advantageous to improve the glossiness of the toner, it exhibits a disadvantage of lowering the offset resistance and durability. On the other hand, polyester resins having a high softening point according to a large molecular weight can maintain the viscosity to suppress the offset phenomenon, but have a problem that gloss and low temperature fixability are lowered.

In order to overcome the above problems and achieve improved fixability according to the fixing temperature of the toner and offset resistance in a wide temperature range, the use of two or more binder resins according to molecular weight or softening point is not used alone. It is proposed.

For example, Korean Patent Publication No. 2006-74092 has an acid value of 25 KOH mg / g or less, a softening point of 140 to 215 ° C., and a glass transition temperature of 50 to 70 ° C. in order to improve fixability and offset resistance. Polyester and acid value of high softening point is 40KOH mg / g or less, softening point of 100 to 150 ° C, and glass transition temperature of 50 to 65 A toner composition comprising a polyester having a low softening point of ° C is disclosed.

Japanese Patent Application Laid-Open No. 2007-148085 discloses an electrostatic charge phenomenon in which a polyester resin having a softening point of 145 to 190 ° C and a polyester resin having a softening point of 85 to 130 ° C is used as a binder resin or a binder resin and contains a colorant, a release agent, and the like. A toner for a solvent is disclosed.

As in the prior art, even if two kinds of polyester resins having different softening points are used, there is still a difficult control to ensure compatibility between the resin and the viscosity characteristics according to the temperature during melt kneading.

Along with this, there are many difficulties in achieving instability of performance and various densities of images under various environments, along with problems of fine dispersion of additives used in toner production, compatibility and wettability between binder resins and additives, and the like.

In particular, the uniform dispersion of the toner material using the melt kneading apparatus may be insufficient due to the limitation of the residence time due to the flow characteristics of the continuous kneading apparatus. Even if the residence time is increased as much as possible, the limitations of the inherent dispersion capacity are encountered, and efforts are being made to optimize various preliminary mixing techniques to overcome this. Furthermore, there are cases where fine powder of the toner raw material is hindered by cohesion between fine particles and difficulty in mixing at an optimum ratio of toner materials, such as sticking to the inner wall of the melt kneading apparatus.

As a result of continuous research, the present inventors have used two kinds of polyester resins having relatively different softening points as binder resins, and considering the diversity of physical properties depending on the temperature of the binder resin and other toner manufacturing materials (raw materials) It has been found that by setting the conditions of the melt kneading process, the above limitations of the prior art can be overcome. In particular, in consideration of the softening point of the two kinds of binder resins, the fluidity according to the softening point of these binder resin mixtures, and the like, the input method of the raw materials during the melt kneading process is specifically designed, and the temperature gradient conditions in the melt kneading apparatus are adjusted. By setting, it was confirmed that the toner properties (gloss, low temperature fixability, offset resistance, dispersibility and fusion / deposition property) significantly improved compared to the prior art can be achieved.

Accordingly, it is an object of the present invention to provide a method for producing a toner, in which melting and kneading minimizes agglomeration between fine particles of toner manufacturing materials, improves fluidity, and stabilizes dispersibility and mixing ratio.

According to an embodiment of the invention,

As a binder, a toner manufacturing raw material containing a high softening point and a low softening point polyester resin having a difference in softening point of 10 to 70 ° C,

Melting and kneading at a temperature condition of the following general formulas 1 to 3 in an extruder including a raw material inlet having at least one raw material inlet, a kneading portion having at least one kneading block, and an outlet of melt kneaded raw material;

Provided is a method of manufacturing a toner for developing an electrostatic image, comprising:

[Formula 1]

0.5 (Ta + Tb) -50 ° C≤T (1) ≤0.5 (Ta + Tb) + 30 ° C

[Formula 2]

0.5 (Ta + Tb) + 20 ° C≤T (2) ≤Ta + 60 ° C

[Formula 3]

0.5 (Ta + Tb) -25 ° C. ≦ T (3) ≦ 0.5 (Ta + Tb) + 45 ° C.,

In the above, T (1) is the temperature from the starting position of the raw material input portion to the previous to the kneading portion, T (2) is the temperature of the kneading portion, and T (3) is the discharge portion at the end position of the kneading portion Temperature before, and

Ta is the softening temperature of the high softening point polyester resin, and Tb is the softening temperature of the low softening point polyester resin.

According to a preferred embodiment of the present invention, the raw material inlet comprises a plurality of raw material inlets, wherein each of the high softening point and the low softening point polyester resin is a raw material inlet (extrusion) of different positions in the extrusion direction of the plurality of raw material inlets Are supplied separately from each other via two or more raw material inlets arranged at intervals in the direction. As such, it is possible to give a variety of residence times of the high softening point and the low softening point polyester resin by using a raw material inlet having a different position in the extrusion direction. Particularly preferably, a kneading block (1 or 2 or more) may be located between the raw material inlets which are differently positioned in the extrusion direction in the extruder, in which case the low softening point polyester resin is provided through the raw material inlet located before the kneading block. On the other hand, the high softening point polyester resin is advantageously supplied through a raw material inlet located after the kneading block.

According to another preferred embodiment of the present invention, the toner may be manufactured by mixing the high softening point and the low softening point polyester resin, and supplying the mixture through a raw material input unit to melt kneading. This aspect may be applied both to an extruder equipped with a single raw material inlet, as well as to an extruder equipped with a plurality of raw material inlets (including raw material inlets arranged at the same position and different positions in the extrusion direction).

The toner manufacturing method according to the present invention minimizes agglomeration between fine particles of toner materials during melt kneading, improves fluidity in consideration of viscosity characteristics depending on temperature between two binder resins having different softening point bands, By stabilizing the dispersibility and its mixing ratio, it is possible to achieve significantly improved toner properties (gloss, low temperature fixability, offset resistance, dispersibility and fusion / deposition), and because it has the advantage of obtaining a good image Broad commercialization is expected in the future.

The present invention can be achieved by the following description with reference to the accompanying drawings. It is to be understood that the preferred embodiments of the invention are described, but the invention is not necessarily limited thereto.

Binder resin

According to the present invention, two kinds of polyester resins having different softening point ranges are used as the binder for toner production. Such resins can typically be prepared from esterification and polycondensation reactions of aromatic dicarboxylic acids, aromatic diols and aliphatic diol components. At this time, the softening point difference between both resins is in the range of about 10 to 70 ° C, more preferably about 15 to 40 ° C. Generally, a polyester resin having a high molecular weight and a high softening point is suitable for increasing the durability of the toner and improving the shape of the image after fixing to the transfer object, while a polyester having a low molecular weight and a low softening point is necessary for improving fluidity and fixability. Resin is easy. Therefore, in order to obtain an improved toner by utilizing the properties between other softening points and resins having molecular weights accordingly, it is necessary to keep the difference of softening points within the above-mentioned range.

According to a preferred aspect of the present invention, since the binder resin has a low glass transition point and a softening point compared with other resins that have been used as binders of toners in the past, image formation at low fixing temperatures is facilitated, and Use something that can increase durability and efficiency. Typically, two types of binder resins having a difference in the softening point described above among polyester resins having a weight average molecular weight of about 8,500 to 220,000 and a softening point of about 100 to 170 ° C. and a glass transition temperature of about 50 to 80 ° C. are selected. It is preferable to use.

Moreover, as long as it has the softening point difference mentioned above, each of the polyester resin of the high softening point, and the polyester resin of the low softening point can also be comprised combining 2 or more types of resin which belongs to the said softening point zone.

In this regard, it is preferable that the resin having a relatively high softening point has a softening point of about 130 to 170 ° C. It is also desirable to have a weight average molecular weight of about 90,000 to 220,000 and a glass transition temperature (Tg) of about 60 to 80 ° C. On the other hand, for a resin having a relatively low softening point, it is preferable to have a softening point of about 100 to 130 ° C. It is also desirable to have a weight average molecular weight of about 8,500 to 90,000 and a glass transition temperature (Tg) of about 50 to 65 ° C.

As described above, in the present invention, two kinds of polyester resins having different molecular weight distributions and corresponding glass transition temperatures and softening points within different ranges can be used to induce uniform mixing and dispersion between binder resins in toner particles. .

In the present invention, the weight ratio of the high softening point of the polyester resin to the low softening point of the polyester resin may vary depending on the fixing temperature range of the toner particles and the relatively required function, preferably about 0.1 to 9.0, more preferably Preferably in the range of about 0.5 to 7.5. The total content of the two polyester resins, that is, the total content of the binder resin, is preferably in the range of about 80 to 98.2 wt%, more preferably about 85 to 95 wt%, based on the total weight of the toner.

According to the present invention, as the binder resin constituting the toner, styrene-based resin may be used as the above-described two kinds of polyester resins; Acrylic resins; Styrene-acrylic resins; Polyolefin-based resins such as polyethylene-based and polypropylene-based resins; Polyamide-based resins; Polyurethane-based resins; Polycarbonate resins; And at least one or more selected from the group consisting of copolymers or condensates thereof. In this case, the content of such additional resin is preferably up to about 25% by weight, more preferably up to about 20% by weight in the binder resin.

Hereinafter, the additive component which is used together with the above-described binder and constitutes a component of the toner will be described. Each of these additives may be added to the binder resin alone, but it is preferable to use a suitable combination in view of the required properties of the toner.

coloring agent

According to the present invention, a colorant is used together with the above-mentioned binder resin in the production of the toner. The colorant is contained both in the raw material containing each of the two polyester resins described above, or in any of the raw materials containing each of the two polyester resins to be introduced into a melt kneading apparatus such as an extruder. It may be.

The kind of the colorant may be any one known in the art without particular limitation, and specifically, various pigments and dyes of inorganic or organic may be used. As black pigment, carbon black such as furnace black, acetylene black, thermal black, lamp black, copper oxide, various iron oxides, manganese dioxide, aniline black, etc. Can be. The content of the colorant is preferably in the range of about 1 to 7% by weight, more preferably about 2 to 6% by weight, based on the total weight of the toner.

Release agent

According to the present invention, a wax component can be used as the release agent. Such wax components may be any known in the art without particular limitation.

In this regard, low melting point waxes having relatively low viscosity include carnauba wax, rice wax, natural plant ester wax such as montan wax, paraffin wax, and the like. Examples of the wax include synthetic hydrocarbon waxes such as polyethylene wax and polypropylene wax.

According to a preferred embodiment of the present invention, the cold-offset (hot-offset) and the hot-offset (compensation) according to the viscosity characteristics of the wax according to the temperature is compensated, and the paper jam (wrap jam) in the fixing unit during image formation In order not to prevent them, two or more waxes having different melting points (and thus different viscosities) may be used in combination.

It is preferable that melting | fusing point of the low melting point wax which has a low viscosity is 60-100 degreeC, and melting | fusing point of high melting point wax is preferable that it is 120-170 degreeC.

On the other hand, the content of the release agent is preferably in the range of about 0.5 to 7% by weight, more preferably about 1 to 6% by weight, based on the total weight of the toner. In addition, in order to prevent a problem caused by dispersion during melt kneading, it may be used by master batch with other additives such as binder resin, colorant.

Charge control agent

According to the present invention, a charge control agent can be added for the production of a toner capable of obtaining a high image by stabilizing charging characteristics of the toner for developing an electrostatic charge image and minimizing generation of residual amount during image formation. Such charge control agents are not particularly limited, but may include quaternary ammonium salts, resins containing quaternary ammonium salts or amino groups, azo metal compounds, acetyl acetone metal compounds and their complexes, benzyl acids and aromatic hydroxycarboxes. Main acid system, various black new system, salicylic acid system, phthalocyanine, perylene, quinacridone, metal salt or complex of nitrogen compound, boron compound or complex thereof, sulfonic acid salt containing carboxyl group, sulfonyl group, Triphenyl methane type, trimethyl ethane type, nigrosine dye, etc. can be used. The content of the charge control agent is preferably in the range of about 0.3 to 6% by weight, more preferably about 1 to 5% by weight, based on the total weight of the toner.

The charge control agent used in the present invention may impart improved compatibility and dispersibility by master batching with binder resin and wax and / or inorganic fine particles.

In addition, the charge control agent may be used in an external process for imparting charging stability of toner particles together with titanium dioxide, polymer powder, and the like.

According to the present invention, the kneaded obtained by melt kneading the binder resin and the additive (e.g., colorant, wax and / or charge control agent) components is subjected to the usual subsequent steps (cooling, pulverization and classification) involved in toner production. Toner in the form of particles (eg having a particle diameter of about 5 to 13 microns). Such a particulate toner can improve flow characteristics, antistatic characteristics, and the like by attaching various additive components to the surface thereof. Below, such an external component is demonstrated. However, in the present specification, the component is described as to adhere to the surface of the toner particles, but in some cases, may be contained by melt kneading in the binder resin together with the above-described components, that is, a colorant, a mold release agent, a charge control agent, and the like. It should be noted.

Inorganic fillers

As described above, according to the present invention, an inorganic filler may be used to improve the physical properties of the toner particles. Such inorganic fillers are not limited to a particular kind, but dimethylchlorosilane, trimethylchlorosilane, methyltrichlorosilane, arylphenylchlorosilane, benzyldimethylchlorosilane, bromine methylchlorosilane, chrommethylchlorosilane, P-chlorophenylchloro Silane coupling agents such as silane, 3-chloropromethyltrimethoxy, vinyltriethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, and hexamethylenedisiragen ) Or silicon dioxide, titanium oxide, aluminum oxide, cerium oxide, zinc oxide, tin oxide, chromium oxide whose surface is hydrophobized by silicon oil or the like. , Copper oxide, iron oxide, zirconium oxide, magnesium oxide, silicon carbide, boron carbide, titanium nitride, zirconium nitride, magnesium fluoride, silica fine powder, alumina (al umina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, barium carbonate, silicon carbide, and the like, which can be used in combination of one or two or more.

In particular, in order to improve the durability and flowability of the toner, at least one of the inorganic particles having a small specific surface area (for example, specific surface area of about 20 to 100 m 2 / g) and the inorganic particles having a large specific surface area (for example, about At least one of 130 to 350 m 2 / g specific surface area) may be mixed and adhered to the toner particle surface. The deposition amount of the inorganic filler is preferably in the range of about 0.2 to 2.5 parts by weight, more preferably about 0.3 to 2.0 parts by weight based on 100 parts by weight of toner particles.

Other additives

In addition to the above-mentioned inorganic fillers, toners may also be charged with a charge control agent and melamine formaldehyde or acrylic styrene resin powder (for example, a particle size of about 0.1 to 2.0 microns) in order to provide charge stability and to improve electrical properties of the toner particles. It can be used combining 1, 2 or more within the range which can maintain the required characteristic of. The deposition amount of the other additive components is preferably about 0.05 to 1.0 parts by weight based on 100 parts by weight of the toner particles.

Melt kneading apparatus

In the conventionally known toner production method, as described above, the raw material for toner production is sufficiently mixed by a mixer such as a Henschel mixer, a turbine type stirrer, a super mixer, a ball mill, and the like, followed by melt kneading such as an open roll type kneader, a single screw or a twin screw extruder. The kneaded product obtained by kneading using a machine is cooled (for example, using air at room temperature), mechanically coarsely ground using an impact mill such as a hammer mill, finely ground by a jet mill, and then classified. Go through the process.

According to one embodiment of the present invention, for melt kneading the raw material for toner production, an extruder comprising a raw material input unit having at least one raw material inlet, a kneading unit having at least one kneading block and a discharge portion of the melt kneaded raw material ( Preferably twin screw extruder).

1 is a view schematically showing the configuration of an extruder that can be used in one embodiment of the present invention, and the present invention is not to be construed as being limited to the illustrated extruder configuration.

In the figure, the raw material inlet A indicates an inlet arranged before the first kneading block. Through this, additives such as colorants, mold release agents (waxes), charge control agents, and optionally inorganic fillers, including binder resins, are introduced into the melt kneading apparatus, alone or in combination, wherein one or more feeding devices capable of controlling the feeding amount are provided. It is preferable to add through.

The raw material injection hole B is arranged to be different from the raw material injection hole A in the extrusion direction, and according to the drawing, the raw material injection hole B is disposed to be close to the first kneading block side between the first kneading block and the second kneading block. This allows additives such as binder resins, colorants, release agents (waxes), charge control agents, and optionally inorganic fillers, alone or in combination, to be introduced into the melt kneading apparatus, and through one or more feeders capable of controlling the feed amount. It is preferable to add.

In addition, the fine powder of the toner obtained by sorting through a series of processes may be reused in the melt kneading process through the inlet.

In this figure, the raw material inlet C is disposed immediately after the second kneading block so as to prevent excessive shearing of the kneaded material due to agglomeration and crushing due to a colorant such as carbon black. side feeding).

The illustrated melt kneading apparatus supplies the raw materials in a free-falling manner by using an input amount adjusting device so that the mixing ratio is uniformly adjusted in the raw material inlet A and the raw material inlet B. At this time, the supply device and the inlet is preferably coated so that the added fine particles do not adhere to the surface.

The plurality of raw material inlets described above may remove gases generated during kneading to induce compatibility and dispersibility of kneaded materials and to remove impurities. In order to double this effect, it is preferable to arrange the vent portion between the raw material inlet (C) and the die (die). Furthermore, a plurality of vent parts may be arranged before and after the kneading block.

In the above-described embodiment, preferably, each of the low softening point and the high softening point polyester resin is melt-kneading apparatus, that is, an extruder (particularly preferably, in a state of being separated from each other using a raw material inlet A and a raw material inlet B). Can be introduced into a twin screw extruder). As such, in consideration of thermal and flow characteristics of polyester resins having different softening point zones used as binder resins, a plurality of raw materials coated on the inner surface of the raw material to prevent adhesion of fine particles to a melt kneading apparatus having a plurality of kneading blocks. By providing an inlet (preferably with one or two or more raw material supply devices) at different positions in the extrusion direction, different residence times can be derived.

As shown in the drawings, according to a preferred embodiment of the present invention, the kneading portion provided in the melt kneading apparatus is preferably composed of a plurality of kneading blocks, each of the raw material inlet (A, B, C) is in this extrusion direction And before and after the kneading block (that is, in the drawing, a raw material inlet is provided before and after the kneading block). Each kneading block is maintained at a temperature of about 100 to 220 ° C, preferably about 120 to 200 ° C, so that smooth kneading can be achieved.

According to the present invention, binder resins having two different softening point zones, softening point and viscosity characteristics of mixed resins thereof, melting point of a releasing agent, etc. are comprehensively taken into consideration, and the temperature gradient conditions in the melt kneading apparatus are distinguished and set, so that the binder resin, It is possible to smoothly disperse raw materials for toner production, such as a release agent (wax), thereby inducing various toner properties.

According to the figure, the melt kneading in the melt kneading apparatus is largely divided into three regions in the extrusion direction. That is, the temperature gradient condition is set by dividing the area 1 from the starting position of the raw material input part to the area before the kneading part, the kneading part 2 and the area 3 from the end position of the kneading part to the area before the discharge part. In the following, the temperature of the region is referred to as T (1), T (2) and T (3), respectively.

In addition, the softening temperature of the polyester resin of the high softening point zone is indicated by Ta, and the softening temperature of the polyester resin of the low softening point zone is denoted by Tb. However, when the high softening point and the low softening point band resin are each composed of two or more types, Ta and Tb may be determined as the average softening point of two or more types of resins belonging to the corresponding softening point band.

In addition, T (in) and T (out) indicate the initial raw material inlet temperature and outlet (outlet) temperature, respectively.

On the other hand, according to a preferred aspect of the present invention, each of the binder resins having the two different softening point zones described above is introduced into the extruder at a constant ratio and melt kneaded, wherein the softening point Tc of the binder mixed resin is preferably 0.5 (Ta +). Tb)-20 ° C to 0.5 (Ta + Tb) + 35 ° C, more preferably in the range of 0.5 (Ta + Tb)-10 ° C to 0.5 (Ta + Tb) + 20 ° C.

On the other hand, the temperature of the melt kneading region 1 described above, that is, T (1), is adjusted in the range of the following general formula (1).

[Formula 1]

0.5 (Ta + Tb) -50 ° C≤T (1) ≤0.5 (Ta + Tb) + 30 ° C

When T (1) is higher than the above-mentioned temperature range, the raw material is not easy to enter due to the fusion and deposition of the inlet side due to the increase of the viscosity of the binder resin, whereas when the temperature falls below the above temperature range, excessive shear force is applied. This may increase the load on the melt kneading apparatus. Preferably, 0.5 (Ta + Tb) -30 ° C. ≦ T (1) ≦ 0.5 (Ta + Tb) + 20 ° C. range.

In addition, the temperature of the above-mentioned melt kneading | mixing area | region 2, ie, T (2), is adjusted in the range of the following general formula (2).

[Formula 2]

0.5 (Ta + Tb) + 20 ° C≤T (2) ≤Ta + 60 ° C

If T (2) is below the above-mentioned temperature range, dispersion and mixing between the binder resin and other additives including a release agent may be insufficient, whereas if too high, thermal decomposition of the binder resin may occur as well. As a result, the viscosity is significantly reduced, and it is difficult to apply the kneading shear force. Moreover, excessive melting may cause the release agent to be concentrated into the binder resin, which makes it difficult to secure the non-constant offset range by making the dispersion unit of the release agent difficult to be fine when crushing the toner particles. Preferably, the range is 0.5 (Ta + Tb) + 30 ° C. ≦ T (2) ≦ Ta + 50 ° C.

On the other hand, the temperature of the above-mentioned melt kneading | mixing area | region 3, ie, T (3), is adjusted in the range of the following general formula (3).

[Formula 3]

0.5 (Ta + Tb) -25 ° C≤T (3) ≤0.5 (Ta + Tb) + 45 ° C

When T (3) exceeds the above-mentioned temperature range, the thermal degradation of the low softening point binder resin, the lowering of the viscosity and the uniform dispersion of the low melting point release agent and other additives, as well as the lowering of the shear force even when kneading is performed It is difficult to maintain that state. On the other hand, when the temperature is lower than the above-mentioned range, the load on the melt kneading apparatus may increase due to excessive shear force of the molten mixture, and the dispersion of the high melting point release agent is not only lowered. Since the dispersion unit is difficult to be fined, it is difficult to secure a constant inner offset range. Preferably, 0.5 (Ta + Tb) -20 ° C. ≦ T (3) ≦ 0.5 (Ta + Tb) + 40 ° C. range.

According to one embodiment of the present invention, the initial raw material inlet temperature, that is, T (in) is preferably set as shown in the following general formula (4).

[Formula 4]

T (in) <Tb

If T (in) is greater than or equal to Tb, it is considered that raw material input may not be smooth due to fusion and deposition of the inlet side due to the increase in the viscosity of the binder resin.

Moreover, it is preferable that discharge | emission part (outlet) temperature, ie, T (out), is set like the following general formula (5).

[Formula 5]

T (in) + 10 ℃ <T (out) <T (in) + 30 ℃

The reason for maintaining the temperature of the discharge portion as described above is that if the temperature of the discharge portion is too low, it may be difficult to maintain the state even if the release agent is excessively exposed to the outer surface due to rapid shrinkage of the binder resin, even if kneading is performed This is because when it is high, it is difficult to expect the effect of even dispersion because the shearing force is hardly applied together with the flowability of the molten mixed dough, and the grinding property can be significantly reduced. Thus, by maintaining the above-mentioned temperature range to maintain compatibility between different softening points and thus resins having different fluidity, it is possible to improve the dischargeability of the molten mixed dough having a wide range of uniform inner offsets.

On the other hand, in the case of Figure 1, the high softening point and the low softening point of the polyester resin is described as the center of the case of being separately supplied to each other through a raw material inlet to change the position in the extrusion direction of the plurality of raw material inlet, in some cases The toner may be prepared by mixing a high softening point and a low softening point polyester resin, and supplying the mixture to an extruder through one or more raw material inlets to melt kneading.

The present invention can be more clearly understood by the following examples, which are only intended to illustrate the present invention and are not intended to limit the scope of the invention.

Example 1

This embodiment was carried out as follows using the melt kneading apparatus shown in FIG. As the binder resin, two kinds of polyester resins having different softening points were used. A relatively low melting point wax and charge control agent were introduced through the raw material inlet A together with the polyester resin A2 having a relatively low softening point. On the other hand, a relatively high melting point wax and charge control agent together with a relatively high softening point of the polyester resin (A1) was introduced through the raw material inlet (B). In addition, the colorant was introduced through the raw material inlet (C).

Based on the weight of the kneaded material, the binder resin was 93.4 wt%, 3.5 wt% carbon black (B1, Mogul-L, Cabot) as colorant, 1.0 wt% quaternary ammonium salt (C1, T-77, Hodogaya Chem.), Carr 1.3 wt% of Nauba wax (D1, Towax-143, Toa Kasei) and 0.8 wt% of low molecular weight polypropylene wax (D4, Viscol 660P, Sanyo Chem.) Were used, wherein the weight ratio of binder resins A1 and A2 ( A1 / A2) was set to 5.7.

Using one or more raw material feeders, T (in) was set at 100 ° C. as described above in the manner of free fall at a feed rate of 15 kg / hr based on binder resin feed and fed through the raw material inlet. Using a twin screw extruder with L / D = 35, T (1) is in the range of 100 to 140 ° C, T (2) is in the range of 150 to 180 ° C, and T (3) is in the range of 120 to 150 ° C. After setting, melt kneading under the conditions of 250 rpm, the molten mixed dough obtained by T (out) at 120 ℃ cooled by using air at room temperature, then coarsely pulverized using a hammer mill, jet mill method 100AFG (Hosokawa Alpine) pulverizer (pulverizer) of the finely pulverized and 50ATP (Hosokawa Alpine) was classified by air flow.

As a result, toner particles having an average particle size of 6 to 10 microns were obtained. Hydrophobic silica (E1, RX300, Aerosil) having a specific surface area of 190 to 230 m 2 / g with respect to 100 parts by weight of the toner particles 1.0 part by weight, hydrophobic silica having a specific surface area of 30 to 70 m 2 / g (E2, H05TD , Wacker) 1.0 parts by weight, and 0.3 parts by weight of acrylic-styrene resin powder (E3, MP-1000, soken chemical co.) And 0.3 parts by weight of melamine formaldehyde powder (E4, EPOSTAR, Nippon Shokubai Co., LTD.) The toner was obtained by high speed mixing / attaching using a Henschel mixer.

Example 2

The same procedure as in Example 1 was carried out except that the mixing ratio between the high softening point polyester resin (A1) and the low softening point polyester resin (A2) was changed.

Example 3

It carried out similarly to the comparative example 1 except having changed the composition ratio between the high softening point polyester resin (A1) and the low softening point polyester resin (A2).

Example 4

First, a master batch was obtained through a primary melt kneading and grinding process using the melt kneading apparatus of FIG. 1 using one polyester resin (A1), a colorant, a wax, a charge control agent, and an inorganic filler. The same manner as in Example 1 except that the master batch, the polyester resin (A2) and other additives were subjected to secondary melt kneading using the melt kneading apparatus shown in FIG. 1 to prepare a toner having the same composition ratio as in Example 1. Was performed.

Example 5

The same procedure as in Example 1 was carried out except that paraffin wax (D2, H1N1, Kato) was used in an amount of 1.3% by weight instead of carnauba wax.

Example 6

Rice wax (D3, Rice Wax, Kenko Corporation) was carried out in the same manner as in Example 1 except that 2.1 wt% was used alone.

Comparative Example 1

According to the conventional toner production method, except that pre-melting raw materials for toner preparation before melt kneading are mixed with a Henschel mixer, the mixture is introduced through one raw material inlet, and melt-kneaded to prepare a toner having the same composition as in Example 1. It was carried out in the same manner as in Example 1.

Comparative Example 2

It carried out similarly to Example 1 except having used polyester resin (A3) independently as binder resin.

Comparative Example 3

It carried out similarly to Example 1 except having used polyester resin (A1) of a high softening point alone as a binder resin.

Comparative Example 4

It carried out similarly to Example 1 except having used the softening point polyester resin (A2) independently as binder resin.

Comparative Example 5

T (1) in the range of 100 to 140 ° C, T (2) in the range of 160 to 200 ° C, T (3) in the range of 200 to 240 ° C, T (in) in the range of 100 ° C, and T (out) The same process as in Example 1 was carried out except that the mixture was melt kneaded at 240 ° C.

Comparative Example 6

T (1) ranges from 180 to 220 ° C, T (2) ranges from 130 to 180 ° C, T (3) ranges from 70 to 105 ° C, T (in) is 200 ° C, and T (out) The same process as in Example 1 was conducted except that the mixture was melt kneaded at 65 ° C.

Comparative Example 7

T (1) ranges from 120 to 180 ° C, T (2) ranges from 220 to 260 ° C, T (3) ranges from 130 to 200 ° C, T (in) is 100 ° C, and T (out) It was carried out in the same manner as in Example 1 except that the melt was kneaded by setting to 65 ℃.

Various physical properties of the toner particles prepared in Examples and Comparative Examples and the binder resins used in the preparation were evaluated as follows, and the results are shown in Tables 1 and 2. In addition, Table 2 shows the final composition ratio of the obtained toner prepared in Examples and Comparative Examples.

(1) Glass transition temperature (Tg, ℃): After using a differential scanning calorimeter (DSC Q100, TA Instrument) at a temperature increase rate of 10 ℃ per minute, and then cooled and the temperature was again measured.

(2) Softening point (° C): Using a flow tester (CFT-500D, Shimadzu), a nozzle of 1 mm in diameter and 1 mm in height was measured at a heating rate of 6 ° C. per minute at a load of 20 kgf.

(3) Molecular weight (Mw): A sample of 0.3-0.5% concentration was prepared using a THF solution in a 500 kPa column and measured under water at 40 ° C. using a Water Model 2690 at a flow rate of 1 ml / min.

(4) Glossiness: An image is obtained by adjusting the toner concentration on the paper to about 1.0 g / cm 2 using a fixing unit having a printing speed of 100 mm / s and 140 ° C. in order to evaluate the density and gloss of image quality. Was measured in the toner and the incident angle was 60 degrees using Suga UGV-5D.

(5) Low temperature fixability: Fixing temperature was set at a roller speed of 100 mm / s with a fixing roller not coated with silicone oil, and the fixing temperature was set at the minimum temperature when the toner started fixing to paper using a printer which can change the temperature. The temperature was visually observed and judged based on whether or not agglomeration of the fixed image occurred.

◎ (very good): Fusing temperature is lower than 120 ° C

○ (good): The fixing temperature is 120 ° C or more and less than 130 ° C

△ (usable): Fusing temperature is 130 ° C or more and less than 160 ° C

× (defect): fixing temperature is 160 degreeC or more

(5) Offset resistance: It was visually observed whether or not toner contamination occurred on the transfer paper when the toner image was fixed using the printer. At this time, the heat roller setting temperature of the fixing roller device was repeatedly raised in the state of sequentially raising the offset temperature.

◎ (very good): offset generation temperature is 240 ° C. or more

○ (good): offset generation temperature is 220 ° C or more and less than 240 ° C

△ (usable): Offset generation temperature is 200 ° C or more and less than 220 ° C

X (defect): Offset generation temperature is 200 degrees C or less

(6) Dispersibility: Toner particles are cut to a thickness of about 0.3 microns using a cutter such as a microtome, taken 1000 times with a transmission electron microscope, and the maximum diameter in the field of view of 200 microns x 200 microns is determined. The distribution of aggregates except for the branched particles was visually observed and evaluated according to the number (percentage) of aggregates of 18 micrometers (μm) or more relative to the number of particles having a diameter or long diameter of 5 micrometers (μm) or more in the visual field.

◎ (very good): When dispersibility is good and the number of aggregates is 10% or less

○ (good): When the dispersibility is good and the number of aggregates is in the range of 11 to 20%

Δ (normal): When dispersibility is normal and the number of aggregates is in the range of 11 to 20%

× (poor): when the number of aggregates is 20% or more

(7) Fusion / Deposition: After melt kneading, comparative evaluation was made according to the degree of deposition remaining on the wall of the feeder and the extruder and the screw blades. In the case of the comparative examples 1 and 2, the stirring blade of the mixer and its wall surface were also observed.

○ (good): No welding or deposit is recognized on either the wall or the screw.

Δ (normal): A slight fusion / deposit on the wall and the screw is recognized.

X (poor): A large amount of fusion / deposit is recognized on the wall and the screw.

TABLE 1

Binder resin A1 A2 A3 Tg (占 폚) 68 63 65 Molecular Weight 146,472 48,935 95,603 Softening point (℃) 140 115 130

TABLE 2

Example Comparative example One 2 3 4 5 6 One 2 3 4 5 6 7 Binder resin
(Weight ratio) A1 85 60 20 85 85 85 85 - 100 - 85 85 85 A2 15 40 80 15 15 15 15 - - 100 15 15 15 A3 - - - - - - - 100 - - - - - B1 (wt%) 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 C1 (wt%) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 D1 (wt%) 1.3 1.3 1.3 1.3 - - 1.3 1.3 1.3 1.3 1.3 1.3 1.3 D2 (wt%) - - - - 1.3 - - - - - - - - D3 (wt%) - - - - - 2.1 - - - - - - - D4 (wt%) 0.8 0.8 0.8 0.8 0.8 - 0.8 0.8 0.8 0.8 0.8 0.8 0.8 E1 (part by weight) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 E2 (part by weight) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 E3 (part by weight) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 E4 (part by weight) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Luster 26 25 22 23 24 25 14 18 16 19 15 18 17 Low temperature fixability ◎ ◎ ◎ ◎ ○ ○ ○ × × × × × × Offset resistance ◎ ◎ ○ ◎ ○ ◎ ○ × × × × × × Dispersibility ◎ ◎ ◎ ◎ ○ ◎ △ ○ ○ ○ × × × Fusion / Deposition ○ ○ ○ ○ ○ ○ × △ △ △ × × ×

As can be seen from Table 2, toners prepared by using two kinds of polyester resins having different softening points as binders in Examples 1 to 6 had overall physical properties (gloss, low temperature fixability, offset resistance, dispersibility and Fusion / deposition) was good or good. In particular, it was confirmed that the compatibility and dispersibility between the additives is excellent by providing a variety of residence times by using a plurality of inlets having different positions in the extrusion direction, and the glossiness according to the inherent physical properties of the binder resin is also good. In addition, as can be seen from Examples 1, 5, and 6, even when one or two or more waxes were added, the effect of the wax addition was obtained. In particular, in the case of Example 4, the master batch form was prepared by preliminary melt kneading, and then toner was manufactured by performing the melt kneading to obtain a better image.

On the other hand, toner particles prepared by mixing the raw materials for toner production using a mixer as in Comparative Example 1, and then mixing the mixture through a single raw material inlet and melt kneading, have a particularly reduced property in terms of fusion / deposition. Indicated. It is determined that the compatibility between the components during melt kneading is lowered due to the uneven mixing ratio and the generation of aggregation between the fine particles from the mixing step of the raw material using the mixer. As a result, in the case of Comparative Example 1, it was found that the low-temperature dispersibility of the toner particles was not satisfactory, and the glossiness of the image formed therefrom was also lowered.

In the case of the toner manufactured by using one kind of polyester resin alone as binder resin as in Comparative Examples 2 to 4, low softening point and offset resistance are not obtained because the softening point does not achieve the effect of achieving compatibility between different binder resins. And decreased in terms of fusion / deposition.

As in Comparative Example 5, when it was higher than T (3) set in the present invention, the viscosity of the melt mixture was markedly lowered, thus causing unevenness between the toner raw materials due to low shear force and bias of additives such as wax. In addition, as the discharge portion is set too high, the excessive flowability of the molten mixed dough resulted in reduced discharge and pulverization.

In the case of Comparative Example 6, the excessively high temperature of T (in) caused the difficulty of the initial raw material input, the viscosity of the binder resin of the low softening point is lowered and decomposition due to the temperature setting of too high T (1) Even with fine shearing of additives such as wax with low shear, it was difficult to maintain the state. Further, T (3) is significantly lower than T (1), and at the same time, due to the temperature of the discharge portion and the excessively low temperature of T (out), the viscosity of the melted kneaded becomes high and the dischargeability deteriorates as the extruder load increases, It caused a decrease in productivity. In particular, due to the pulling phenomenon of the additives such as wax, it was difficult to obtain the expected effect of the addition.

In the case of Comparative Example 7, remarkably high T (2) makes it difficult to apply the kneading shear force due to the decrease in viscosity, resulting in non-uniform dispersion, and could not secure the expected properties of the binder resin due to decomposition of the resin. In addition, due to the setting of the temperature of the discharge portion, T (out), which shows a sharp difference with respect to T (3), an improved kneading state is maintained due to the excessive exposure of the release agent due to the rapid shrinkage of the binder resin and the discharge of uneven molten mixed dough. It was hard to do.

As such, Comparative Examples 5 to 7 showed all deterioration in low temperature fixability, offset resistance, dispersibility and fusion / deposition.

As described above, the present invention uses two kinds of polyester resins having different softening point bands (due to different molecular weights) as binder resins, and includes a plurality of raw material inlets and a kneading portion having one or more kneading blocks. An extruder as a melt kneading apparatus is used, and the high softening point and the low softening point polyester resin are each supplied separately from each other through at least two raw material inlets installed at different positions in the extrusion direction. Therefore, the diversity of residence time was given according to the characteristic of each binder resin. In addition, by setting the temperature gradient conditions in the extruder, which improves the compatibility and dispersibility between the binder resins having different softening point bands or the binder resin and the additive components, centering on the kneading part, stable charging and durability, and a wide ratio High quality images can be obtained under anti-offset.

Furthermore, the binder resin and the colorant, the charge control agent, the release agent, and the like are first melt kneaded to prepare a master batch, and the binder resin having a softening point different from the resin used in the master batch according to the physical properties and composition ratio of the toner (and And / or other melt kneading with other additives) may improve toner production efficiency and improve processability.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

1 is a view schematically showing the configuration of an extruder usable in the preferred embodiment of the present invention.

Claims (18)

As a binder, a toner manufacturing raw material containing a high softening point and a low softening point polyester resin having a difference in softening point of 10 to 70 ° C, Melting and kneading at a temperature condition of the following general formulas 1 to 3 in an extruder including a raw material inlet having at least one raw material inlet, a kneading portion having at least one kneading block, and an outlet of melt kneaded raw material; Method of manufacturing a toner for electrostatic image development comprising: [Formula 1] 0.5 (Ta + Tb) -50 ° C≤T (1) ≤0.5 (Ta + Tb) + 30 ° C [Formula 2] 0.5 (Ta + Tb) + 20 ° C≤T (2) ≤Ta + 60 ° C [Formula 3] 0.5 (Ta + Tb) -25 ° C. ≦ T (3) ≦ 0.5 (Ta + Tb) + 45 ° C., In the above formula, T (1) is the temperature from the starting position of the raw material input part to before the kneading part, T (2) is the temperature of the kneading part, and T (3) is the discharge part at the end position of the kneading part. Temperature before, and Ta is the softening temperature of the high softening point polyester resin, and Tb is the softening temperature of the low softening point polyester resin. The method of manufacturing a toner for electrostatic image development according to claim 1, wherein the raw material input part has a plurality of raw material input ports. The method of claim 1, wherein the kneading portion has a plurality of kneading blocks. The method of claim 2, wherein each of the high softening point and the low softening point polyester resin is separately supplied through a raw material inlet having a different position in the extrusion direction among the plurality of raw material inlets. The method of claim 1, wherein the high softening point and the low softening point polyester resin are mixed and supplied through the raw material input part. 5. The method according to claim 4, wherein the at least one kneading block is located between the raw material inlets which differ in position in the extrusion direction. The method of claim 1 or 2, wherein the temperature, T (in), of the first inlet of the raw material inlet is set as in the following general formula (4): [Formula 4] T (in) <Tb. The method of claim 7, wherein the discharge portion temperature, T (out) is set as shown in the general formula (5). [Formula 5] T (in) + 10 ° C. <T (out) <T (in) + 30 ° C. The method of claim 1, wherein the high softening point and low softening point polyester resin is selected from polyester resins having a weight average molecular weight of 8,500 to 220,000, a softening point of 100 to 170 ℃ and a glass transition temperature of 50 to 80 ℃, respectively. A method for producing an electrostatic charge image developing toner. 10. The method of claim 9, wherein the high softening polyester resin is at least 1 or 2 resins having a softening point of 130 to 170 ° C, a weight average molecular weight of 90,000 to 220,000, and a glass transition temperature (Tg) range of 60 to 80 ° C; And the low softening point of the polyester resin is a static charge phase characterized in that one or two or more resins having a softening point of 100 to 130 ℃, a weight average molecular weight of 8,500 to 90,000 and a glass transition temperature (Tg) range of 50 to 65 ℃ Method for producing a developing toner.  The method of claim 1, wherein the weight ratio of the polyester resin of the high softening point to the polyester resin of the low softening point is 0.1 to 9.0. The raw material for preparing toner according to claim 1, wherein the raw material for toner production comprises 80 to 98.2 wt% of binder resin, 1 to 7 wt% of colorant, 0.5 to 7 wt% of release agent, and 0.3 to 6 wt% of charge control agent. A method for producing an electrostatic charge image developing toner. 13. The method for producing an electrostatic image developing toner according to claim 12, wherein one kind or two kinds of waxes having different melting points are used as the release agent. 14. The method of manufacturing a toner for electrostatic image development according to claim 13, wherein the melting point of the low melting wax is 60 to 100 DEG C and the melting point of the high melting wax is 120 to 170 DEG C. of the two waxes. The method according to claim 1, wherein one of the high softening point and the low softening point polyester resin and at least a part of at least one additive selected from the group consisting of a colorant, a wax and a charge control agent are preliminarily melt kneaded to prepare a master batch. , The master batch and the other softening point polyester resin and additives are fed into the extruder and melt kneaded, characterized in that the manufacturing method of the toner for electrostatic image development. The method of claim 1, further comprising cooling, pulverizing, and classifying the melted kneaded product to prepare toner in the form of particles. 17. The method of claim 16, further comprising externally adding 0.2 to 2.5 parts by weight of an inorganic filler with respect to 100 parts by weight of the toner particles. 18. The method of claim 16 or 17, further comprising adding 0.05 to 1.0 parts by weight of a charge control agent or a charge stabilizer to 100 parts by weight of the toner particles.

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