JP3436067B2 - Full-color toner composition and full-color image forming method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic toner,
Particularly, the present invention aims to provide a full-color toner composition suitable for forming a color image and a full-color image forming method using the same.

[0002]

2. Description of the Related Art A color developing method is based on a three-color synthesizing method such as a subtractive coloring method and, as described in US Pat. No. 2,962,374, at least three electrostatic latent images are formed. After formation, it is common to develop with at least three different color toners and synthesize on copy paper. In this case, compared to black and white development, which requires one development and transfer process,
In color development, the thickness of the fixed image increases by the amount of several types of toner layers that are stacked, and the image area is larger than that of a black-and-white original, so if the film strength of the fixed image is low, the fixed image will crack. There is a risk that the gloss will be impaired or that an image defect will occur when folded. Therefore, the fixed color toner is required to have appropriate gloss and excellent film strength.

Generally, the factor that governs the fixing properties of toner is the physical properties of the binder resin which is the main component of the toner, and typical binder resins for toner are styrene-acrylic resins and polyester resins. To be

Styrene-acrylic resins generally have a high softening point temperature and are suitable for obtaining an output image having low gloss, but a very high amount of heat is required for obtaining an output image having high gloss. It is difficult to achieve this within a limited power consumption range, and therefore an increase in the size of the device and an increase in power consumption are inevitable. Further, lowering the molecular weight of the styrene-acrylic resin leads to a decrease in image strength, and there is a problem in that a fixed image has defects such as cracking due to bending or the like.

On the other hand, polyester resins are often used in toners of electrophotographic color image forming apparatuses currently on the market, and generally have a relatively low softening point temperature,
It is suitable for obtaining a fixed image having high gloss. Also, from the viewpoint of the film strength of a fixed image, it is known that a polyester resin having a large molecular cohesive force is excellent.

[0006] Pigments and dyes are used as colorants, which are other important components that characterize toner, and those using pigments are, for example, Japanese Patent Publication No. 49-46951.
Examples thereof include those described in JP-A-52-172023. In addition, examples of dyes that can be used include, for example, JP-A-57-130043 and JP-A-57-13004.
Those described in Japanese Patent No. 4 are cited.

Conventionally, azo lake pigments, anthraquinone dyes, quinacridone pigments, rhodamine dyes and their lake pigments are often used as colorants for magenta toners for color electrophotography. Among the above colorants, the quinacridone-based pigment is a bluish magenta pigment, so that it reproduces a blue color in a process color well and has excellent storability. Therefore, it is suitable as a magenta colorant. However, this pigment has a problem that the red color of the process color is poorly reproduced due to its color characteristics. Azo lake pigments are also often used as magenta colorants. Since this pigment is a reddish magenta pigment, it has good reproducibility of process color red and strong coloring power compared to other magenta pigments, but its hue changes due to long-term exposure to light. It has the problem of being lost. Rhodamine dyes and their lake pigments are color materials that have good color development in process colors and good reproduction of red to blue, but their light resistance is extremely poor, and there is a problem that the hue changes when exposed to light for a short time. Have Disazo pigments, monoazo pigments and the like are often used as colorants for yellow toners. Disazo pigments have a problem that they have poor light resistance and change in hue when exposed to light for a long time.Many monoazo pigments have excellent light resistance, but have strong hiding power and transparency. Therefore, it is not suitable as a colorant for full color.

As described above, the full-color image obtained by the color toner containing the conventionally used colorant is
It is difficult to achieve both a sufficient color reproduction range and full-color image storability due to light exposure.

[0009]

Therefore, the present invention has been made in view of the above situation in the prior art to improve the situation. That is, an object of the present invention is to provide a full-color toner composition having excellent color reproducibility and having no hue change due to light exposure of a full-color image, which is excellent in hue preservation of a formed image, and a full-color image using the same. It is to provide a forming method.

[0010]

The inventors of the present invention have conducted extensive studies to find a colorant for a full color toner for color electrophotography which is excellent in color developability, color reproducibility and light resistance, and as a result, C ． I pigment red 122 and C.I. I Pigment Red 57: 1, C.I. to Cyan toner.
C. I. Pigment Blue 15: 3, yellow toner with C.I. I
It has been found that the above problems can be solved by containing Pigment Yellow 180 as a colorant, and the present invention has been completed.

The magenta toner, cyan toner of the present invention,
A full-color toner consisting of three colors of yellow toner or four colors obtained by adding black toner to the toner is composed of a binder resin and a colorant, and the binder resin of each toner has a number average molecular weight Mn of 2500 to 4500. , Weight average molecular weight Mw = 7000 to 30,000, and softening point of 95 to
It is essential to use a polyester resin having a glass transition point of 120 ° C and a glass transition point of 60 to 75 ° C, and use the specific dye described above as a colorant. Preferably, the colorant is a magenta toner. For example, C. I pigment red 122 aqueous paste and C.I. I Pigment Red 57: 1 aqueous paste and the same polyester resin as the binder resin are kneaded at a temperature not lower than the softening point of the resin under atmospheric pressure and subjected to a flushing treatment, or a flushing treatment product or the same colorant Using a high-concentration pigment pellet prepared by heating and melting the dry pigment and the polyester resin while applying a high shearing force, for example, by means of a heating type two or three rolls If it is a toner, C.I. I. Pigment Blue 15: 3 and the above polyester resin, the obtained flushing product or high-concentration pigment pellets is used. It is preferable to use the flushing-treated product obtained by using I Pigment Yellow 180 and the polyester resin, or a high-concentration pigment pellet.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

In the color toner composition of the present invention, the binder resin of the toner or the resin which can be used for the flushing treatment for preparing a suitable colorant if desired and the high-concentration pigment pellets has a number average molecular weight Mn of 2500 to 45.
00, weight average molecular weight Mw = 7000 to 30000, softening point 95 to 120 ° C., glass transition point 60 to 75 ° C.

The polyester resin of the present invention is produced from a polyhydric alcohol component and a polycarboxylic acid.

As the polyhydric alcohol component, for example, 2
As a polyhydric alcohol component, ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-
Butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentylene glycol, 1,4-cyclohexanedimethanol, dipropylene glycol,
Polyethylene glycol, polypropylene glycol,
Bisphenol A, hydrogenated bisphenol A, etc. can be used. As a trivalent or higher alcohol component,
Glycerin, sorbitol, 1,4-sorbitan, trimethylolpropane and the like can be used.

Examples of the divalent carboxylic acid component to be condensed with the polyhydric alcohol component include maleic acid, maleic anhydride, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, malonic acid, succinic acid, glutaric acid, Dodecenyl succinic acid, n-octyl succinic acid and lower alkyl esters of these acids can be used.

In the present invention, the binder resin is polyoxyethylene (2,2) as a dihydric alcohol compound component.
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (2,2) -bis (4-hydroxyphenyl) propane, trihydric or higher polyhydric alcohol component and 2
It is preferable to use a divalent carboxylic acid as a constituent.

The polyester resin used in the present invention preferably has a tetrahydrofuran insoluble content of 0 to 10%. When producing such a polyester resin, it is necessary to prepare the polyester resin so that the molecular weight of the produced polyester resin does not become high by a method such as terminating the reaction when the molecular weight falls within an appropriate range.

In the present invention, the polyester resin is
The number average molecular weight Mn needs to be in the range of 2500 to 4500, and more preferably in the range of 2500 to 3500. When the number average molecular weight is more than 4500, the pulverizability is remarkably reduced and the productivity is deteriorated.
If it is less than 00, the strength of the toner image is lowered, and there is a problem that it is easily crushed (toner is crushed in the copying machine developing machine). The weight average molecular weight Mw of the polyester resin is 7
It is necessary to be in the range of 000 to 30,000. When the weight average molecular weight is larger than 30,000, pulverizability is lowered and productivity is deteriorated. On the other hand, when the weight average molecular weight is less than 7,000, polyester molecular cohesive force is lowered and toner releasability is deteriorated.

Further, the polyester resin used in the present invention must have a softening point Tm in the range of 95 ° C to 120 ° C and a glass transition point Tg of 60 ° C to 75 °. It must be in the C range. T
When m is less than 95 ° C, the non-offset temperature region cannot be sufficiently secured, while on the other hand, 120 °
If it exceeds C, low temperature fixing becomes difficult. Also, Tg is 6
If the temperature is lower than 0 ° C, the storage stability of the toner deteriorates,
Aggregation in the developing machine becomes a problem under high temperature and high humidity, while low temperature fixing becomes difficult when the temperature exceeds 75 ° C.

As the colorant, magenta toner may be C.I. I pigment red 122 and C.I. C. I. Pigment Red 57: 1, and C.I. C. I. Pigment Blue 15: 3, and yellow toner C.I. It is necessary to include I Pigment Yellow 180, and preferable color reproducibility and image stability can be realized by combining these colorant pigments. However, if these colorant pigments are contained in the binder resin as they are, Without
From the viewpoint of uniform dispersibility of pigments and color reproducibility, it is preferable to prepare a flushing product or a high-concentration pigment pellet as described below and use it as a colorant.

The flushing treatment of the colorant used in the toner composition of the present invention will be described in detail. An aqueous paste of each pigment listed as the above-mentioned preferable colorant was prepared and shown in the binder resin. Flushing is performed by mixing with the same polyester resin and applying a shearing force under heating conditions using a kneader such as a kneader. here,
By raising the heating temperature above the softening point of the resin, the pigment is completely transferred to the resin, and most of the water is separated out of the system. The water separated here is discharged. The minute water remaining in the system can also be heated and kneaded at 100 ° C or higher,
Can be completely removed.

In the thus obtained flushing-treated product, the pigment is uniformly dispersed in the resin matrix in a high proportion. The content of the pigment in the resin at this time is not particularly limited, but is preferably 20 to 60% by weight.

High-concentration pigment pellets that can be preferably used in the toner composition of the present invention are prepared by adding the pigments listed as colorants in the form of dry pigments to the above polyester resin and kneading machine such as a kneader. It is a method of heating and melting and mixing by using, but at this time, by applying a high shearing force or passing through a gap between a plurality of rolls by means such as a heating type two-roll or three-roll, It is preferable to uniformly disperse the pigment in the resin. The content of the pigment in the resin at this time is not particularly limited, but is preferably 20 to 60% by weight.

The colorant containing a high concentration of pigment in the resin matrix contains a high concentration of the pigment uniformly in the same resin as the binder resin constituting the toner. It is possible to obtain a toner having high pigment dispersibility and uniformity as compared with a case where a pigment as a colorant is blended as it is. Of these coloring agents, it is preferable to use the flushing treatment product from the viewpoint of the ease of production and the uniformity of the pigment.

In the toner of the present invention, the polyester resin as the binder resin and the flushing color material or the high-concentration pigment pellets as the colorant are melted and kneaded by a Banbury mixer, a kneader coater, a CM mixer, an extruder or the like. It can be manufactured by crushing, pulverizing and classifying. The average particle size of the obtained toner is preferably about 3 to 9 μm.

In the present invention, the content of the colorant is 0.5 to 15% by weight, preferably 1 to 10% by weight, based on 100 parts by weight of the binder resin. When the content of the present colorant is less than 0.5% by weight, the coloring power of the present colorant becomes weak and sufficient effect cannot be exhibited. When it is more than 15% by weight, the transparency is deteriorated.

In the present invention, a releasing agent may be added to the toner in order to complete offset resistance. The charge control of the toner may be performed by the binder resin or the colorant itself, but a charge control agent that does not cause a problem in color reproduction may be used together if necessary. In order to improve the durability, fluidity or cleaning property of the toner, if necessary, inorganic fine powder of silica, titanium oxide, aluminum oxide, etc., fatty acid or its derivative, and organic fine particles such as metal salt are used. Resin fine particles such as powder, fluorine-based resin, polyethylene fine particles, and resin fine powder such as acrylic resin fine powder can be added as an external additive.

The toner of the present invention is used as a one-component developer or a two-component developer. When used as a two-component developer, it is used as a mixture with a carrier. As the carrier, known carriers such as ferrite, iron oxide powder, nickel or magnetic metal powder carrier, coated carrier obtained by coating these with resin, magnetic powder dispersion type carrier and the like can be used.

The formation of a full-color image in the present invention is
The above-mentioned cyan, magenta, and yellow color toners and, if necessary, black toner can be used in a conventional manner. Specifically, for example, a photoconductor is used by using a copying machine equipped with a charging device, an exposure unit corresponding to each color, three or four developing devices for supplying the developer of each color onto the photoconductor, and a fixing device. After being uniformly charged, first the color toner of the first color is developed, and then similarly, the electrostatic latent images of the second and subsequent colors (latent image forming step) and the development using the color toner (developing step) are sequentially performed. Repeatedly, the obtained toner image is formed on the transfer body as an unfixed image in which toner layers of respective colors are superposed. Thereafter, the unfixed image is fixed by a fixing device to form a desired full-color image.

According to the full-color toner composition of the present invention, a color image having excellent color reproducibility, little fading and good stability can be obtained by an image forming apparatus such as a general-purpose copying machine.

[0032]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. <Production of Polyester> In a four-necked round bottom flask equipped with a stainless steel stirrer, a glass nitrogen gas introduction tube and a flow-down condenser, the polyhydric alcohol component and the polycarboxylic acid component having the raw material compositions described below were prepared. Thrown into
The flask was set in the mantle heater. Then, nitrogen gas was introduced through the gas introduction pipe, and the temperature was raised while maintaining the inside of the flask in an inert gas atmosphere. Then, 0.05 parts of dibutyltin oxide was added to 100 parts of the raw material mixture.
Parts were added, and the reaction was carried out for a predetermined time while maintaining the temperature of the reaction product at 200 ° C. to obtain a polyester resin.

The molecular weight distribution of the obtained polyester resin was measured by the GPC method using tetrahydrofuran as a solvent. Further, the glass transition point Tg is the temperature at which the peak shoulder of the chart obtained by the DSC method is reached, and the softening point Tm is obtained by a flow tester.

(Example 1) <Preparation of magenta toner> (Preparation of flushing colorant) terephthalic acid, ethylene oxide adduct of bisphenol A, bisphenol A
Of 100% by weight of a polyester resin (softening point 110 ° C., glass transition point 69 ° C., number average molecular weight 3100, weight average molecular weight 10300) obtained by the above-mentioned production method using propylene oxide adduct of C. I. Pigment Red 122 pigment part 60 parts by weight (solids content 25 parts by weight) and C.I.
I. Pigment Red 57: 1 40 parts by weight of pigment paste (18 parts by weight as solid content) was kneaded while heating with a kneader, and the phase transition of the pigment started at 90 ° C and the aqueous phase at 130 ° C. And the colored resin phase are completely separated. Here, water is removed from the kneader, and further kneading is continued to evaporate residual water. After completely removing the water,
After cooling, a flushing coloring material was obtained. (Adjustment of magenta toner) A mixture of 80 parts by weight of the same polyester resin used for flushing and 20 parts by weight of a flushing color material is melted and kneaded by an extruder, coarsely pulverized by a cutter mill, and further jet stream is formed. It grind | pulverized using the fine grinder used. The obtained pulverized product is classified using an air classifier, and the average particle size is 7 μm.
Particles were obtained. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a magenta toner. <Adjustment of yellow toner> (Adjustment of flushing colorant) terephthalic acid, ethylene oxide adduct of bisphenol A, bisphenol A
Polyester resin obtained from propylene oxide adduct of glycerin (softening point 110 ° C, glass transition point 69
° C, number average molecular weight 3100, weight average molecular weight 1030
0) 100 parts by weight of C.I. I. Pigment
When 100 parts by weight of the yellow 180 pigment paste (50 parts by weight as a solid content) was kneaded while heating with a kneader, the phase transition of the pigment was started at 90 ° C.
The aqueous phase and the colored resin phase were completely separated at 0 ° C. Remove water from the kneader and continue kneading to evaporate residual water. After completely removing the water, the mixture was cooled to obtain a flushing coloring material. (Adjustment of yellow toner) A mixture of 75 parts by weight of the same polyester resin as that used for flushing and 25 parts by weight of a flushing color material is melted and kneaded by an extruder, coarsely pulverized by a cutter mill, and a jet stream is generated. It grind | pulverized using the fine grinder used. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a yellow toner. <Adjustment of cyan toner> (Adjustment of flushing colorant) terephthalic acid, ethylene oxide adduct of bisphenol A, bisphenol A
Polyester resin obtained from propylene oxide adduct of glycerin (softening point 110 ° C, glass transition point 69
° C, number average molecular weight 3100, weight average molecular weight 1030
0) 100 parts by weight of C.I. I. Pigment
When 100 parts by weight of Blue 15: 3 pigment paste (50 parts by weight as a solid content) was kneaded while heating with a kneader, the phase transition of the pigment was started at 90 ° C.
The aqueous phase and the colored resin phase were completely separated at 0 ° C. Remove water from the kneader and continue kneading to evaporate residual water. After completely removing the water, the mixture was cooled to obtain a flushing coloring material. (Adjustment of cyan toner) A mixture of 85 parts by weight of the same polyester resin used for flushing and 15 parts by weight of flushing color material is melted and kneaded by an extruder, coarsely pulverized by a cutter mill, and further jet stream is formed. It grind | pulverized using the fine grinder used. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of the particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a cyan toner.

Example 2 <Preparation of Magenta Toner> (Preparation of High Concentration Pigment Pellets) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. PigmentRe
30 parts by weight of dry pigment of d. I. Pigme
20 parts by weight of dry pigment of nt Red 57: 1 was heated and melted and mixed by a Banbury mixer, and further passed 5 times by a heating type three-roll to obtain high concentration pigment pellets. (Preparation of magenta toner) A mixture of 80 parts by weight of the same polyester resin as used for preparation of high-concentration pigment pellets and parts by weight of high-concentration pigment pellets is melted and kneaded by an extruder and coarsely pulverized by a cutter mill. Further, it was crushed using a fine crusher using a jet stream. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a magenta toner. <Preparation of Yellow Toner> (Preparation of High Concentration Pigment Pellets) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. Pigment Ye
50 parts by weight of the dry pigment of low 180 was heated and melt-mixed with a Banbury mixer, and further passed through a heating type three-roll five times to obtain high-concentration pigment pellets. (Adjustment of yellow toner) A mixture of 75 parts by weight of the same polyester resin used for adjusting the high-concentration pigment pellets and 25 parts by weight of the high-concentration pigment pellets is melted and kneaded by an extruder and coarsely pulverized by a cutter mill. Then, it was pulverized using a fine pulverizer using a jet stream. Classify the obtained pulverized product using an air classifier,
Particles with an average particle size of 7 microns were obtained. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a yellow toner. <Preparation of cyan toner> (Preparation of high-concentration pigment pellet) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. Pigment Bl
50 parts by weight of the dry pigment of ue 15: 3 was heated and melted and mixed by a Banbury mixer, and further passed through a heating type three-roll five times to obtain high concentration pigment pellets. (Preparation of cyan toner) A mixture of 85 parts by weight of the same polyester resin as used for preparation of the high-concentration pigment pellets and 15 parts by weight of a flushing coloring material is melted and kneaded by an extruder and coarsely pulverized by a cutter mill. Further, it was crushed using a fine crusher using a jet stream. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of the particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a cyan toner.

Comparative Example 1 <Preparation of Magenta Toner> (Preparation of High Concentration Pigment Pellets) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. PigmentRe
50 parts by weight of d 81: 1 dry pigment is heated and melt-mixed with a Banbury mixer, and further 5 with a heating type three-roll.
This was passed twice to obtain high-concentration pigment pellets. (Preparation of magenta toner) A mixture of 80 parts by weight of the same polyester resin as used for the high-concentration pigment pellets and 20 parts by weight of the high-concentration pigment pellets is melted and kneaded by an extruder and coarsely pulverized by a cutter mill,
Further, it was pulverized using a fine pulverizer using a jet stream. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a magenta toner. <Yellow Toner> The yellow toner of Example 1 was used. <Cyan Toner> The cyan toner of Example 1 was used.

(Example 3) <Magenta Toner> The magenta toner of Example 1 was used. <Yellow Toner> The yellow toner of Example 1 was used. <Cyan Toner> The cyan toner of Example 1 was used. <Black toner> Carbon black (Mitsubishi Chemical Co., particle size:
50 nm) was used.

Comparative Example 2 <Adjustment of Magenta Toner> (Adjustment of Flushing Coloring Material) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. PigmentRed
90 parts by weight of 122 pigment paste (40% as solid content
(Parts by weight) was kneaded while heating with a kneader,
The phase transition of the pigment was started at 90 ° C, and the aqueous phase and the colored resin phase were completely separated at 130 ° C. Remove water from the kneader and continue kneading to evaporate residual water. After completely removing the water, the mixture was cooled to obtain a flushing coloring material. (Adjustment of magenta toner) A mixture of 80 parts by weight of the same polyester resin used for flushing and 20 parts by weight of a flushing color material is melted and kneaded by an extruder, coarsely pulverized by a cutter mill, and further jet stream is formed. It grind | pulverized using the fine grinder used. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a magenta toner. <Adjustment of Yellow Toner> (Adjustment of Flushing Coloring Material) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. PigmentYel
When 100 parts by weight of low 17 pigment paste (50 parts by weight as a solid content) was kneaded while heating with a kneader, the phase transition of the pigment was started at 90 ° C.
At, the aqueous phase and the colored resin phase were completely separated. Remove water from the kneader and continue kneading to evaporate residual water. After completely removing the water, the mixture was cooled to obtain a flushing coloring material. (Adjustment of Yellow Toner) A mixture of 82 parts by weight of the same polyester resin as used for flushing and 18 parts by weight of flushing color material is melted and kneaded by an extruder, coarsely pulverized by a cutter mill, and further jet stream is generated. It grind | pulverized using the fine grinder used. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a yellow toner. <Cyan Toner> The cyan toner of Example 1 was used.

Comparative Example 3 <Adjustment of Magenta Toner> (Adjustment of Flushing Coloring Material) 100 parts by weight of the polyester resin used in Example 1 and C.I. I. PigmentRed
When 100 parts by weight of a 57: 1 pigment paste (50 parts by weight as a solid content) was kneaded while heating with a kneader, the phase transition of the pigment was started at 90 ° C, and the pigment was colored with the aqueous phase at 130 ° C. The resin phase was completely separated. Remove water from the kneader and continue kneading to evaporate residual water. After completely removing the water, the mixture was cooled to obtain a flushing coloring material. (Adjustment of magenta toner) A mixture of 85 parts by weight of the same polyester resin as that used for flushing and 15 parts by weight of the flushing color material is melted and kneaded by an extruder, coarsely pulverized by a cutter mill, and further jet stream is formed. It grind | pulverized using the fine grinder used. The obtained pulverized product was classified using an air classifier to obtain particles having an average particle size of 7 microns. 100 parts by weight of these particles and 0.8 parts by weight of titanium oxide fine particles were mixed using a Henschel mixer to obtain a magenta toner. <Yellow Toner> The yellow toner of Example 1 was used. <Cyan Toner> The cyan toner of Example 1 was used.

Image Evaluation Method <Formation of Image with Toner Composition> (Adjustment of Carrier) Spherical iron powder having an average particle diameter of 50 μm and fluorine-containing acrylic resin are used to obtain a film thickness of about 1.0 μm using a kneader coater. To obtain a carrier. (Preparation of Developer) The above Examples 1 to 3 and Comparative Examples 1 to 3
100 parts by weight of the above carrier was mixed with 6 parts by weight of each toner to prepare a developer. (Formation of image) Developers using the toners of Examples 1 to 3 and Comparative Examples 1 to 3 are A-Col manufactured by Fuji Xerox Co., Ltd.
The color image was formed by copying the portrait of a manuscript with patches of three colors of red, green, and blue and the portrait of a person having a large number of intermediate colors. <Evaluation> The image formed by color copying was evaluated as follows. The results are shown in Table 1 below. 1) Evaluation of color reproducibility (by colorimetric color difference meter) The red, green and blue patches of the collected copy were color-measured by X-Rite 968, and the color reproducibility of the original was evaluated according to the following criteria.

◯: Good color reproducibility (ΔE <3) Δ: A deviation from the original color can be confirmed (3 ≦ ΔE <5) ×: Color that is clearly different from the original color (ΔE ≧ 5) 2) Evaluation of reproducibility (by visual inspection) A panelist visually compared the collected originals with patches of three colors and originals of portraits of persons and copies, and evaluated the color reproducibility for the originals based on the following criteria.

◯: Good color reproducibility (no difference from original can be confirmed) Δ: Difference from original color can be confirmed ×: Clearly different from original color 3) Hue change due to light exposure Sun tester Ultraviolet rays (56 w / m ² ) are irradiated using (Shimadzu Corporation), and the hue change after 100 hours irradiation and after 200 hours irradiation is the same as the above-mentioned color reproducibility.
Evaluation was made by a colorimetric color difference meter and visually according to the following criteria.

[0043] ○: No change in hue compared to products not irradiated with ultraviolet rays △: A slight change in hue occurred compared to the product not irradiated with ultraviolet rays ×: A remarkable hue change occurs as compared with the product not irradiated with ultraviolet rays.

[0044]

[Table 1]

As is clear from Table 1, the image formed by using the full-color toner composition of the present invention is composed of three colors of magenta toner, cyan toner and yellow toner, and four colors including black toner. All of them had excellent color reproducibility not only for originals having patches of three colors but also for portraits of people with many intermediate colors, and almost no change in hue was observed even after irradiation with ultraviolet rays. On the other hand, the image formed using the full-color toner composition of Comparative Example not using the specific colorant of the present invention could not satisfy both color reproducibility and hue stability.

[0046]

The full-color toner composition of the present invention has the effects of having good color forming properties and color reproducibility, and having excellent hue stability of images upon exposure to light.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-305083 (JP, A) JP-A-9-54461 (JP, A) JP-A-8-248677 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03G 9/09

Claims (11)

(57) [Claims] 1. A toner for full-color image formation comprising at least three colors of magenta toner, cyan toner and yellow toner, wherein the toner comprises at least a binder resin and a colorant, and as the colorant, magenta toner is C.I. I pigment red 122 and C.I. I Pigment Red 57: 1, cyan toner is C.I. I pigment blue 15: 3, yellow toner is C.I. A full-color toner composition comprising I Pigment Yellow 180. 2. The full-color toner composition according to claim 1, wherein the full-color toner composition comprises four colors of the magenta toner, the cyan toner, the yellow toner, and the black toner. 3. The full-color toner composition according to claim 2, wherein carbon black is used as the black toner. 4. The binder resin has a number average molecular weight Mn = 25.
00-4500, weight average molecular weight Mw = 7000-30
000, softening point 95-120 ° C, glass transition point 6
The full-color toner composition according to any one of claims 1 to 3, which is a polyester resin having a temperature of 0 to 75 ° C. 5. The full-color toner composition according to claim 1, wherein the binder resin has a tetrahydrofuran insoluble content of 0 to 10% by weight. 6. The full-color toner composition according to claim 1, wherein the colorant is contained in an amount of 0.5 to 15 parts by weight based on 100 parts by weight of the binder resin. 7. The full-color toner composition according to claim 1, wherein the toner has an average particle diameter of 3 to 9 μm. 8. The magenta toner as a colorant,
The polyester resin and C.I. I Pigment Red 122
Aqueous paste and C.I. I Pigment Red 57: 1
The flushing product obtained by flushing the aqueous paste of C. or the polyester resin and C.I. I pigment red 122 dry pigment and C.I. A high-concentration pigment pellet prepared by heating and melting a dry pigment of I Pigment Red 57: 1 and mixing while applying a high shearing force is used. The full-color toner composition described. 9. The cyan toner comprises, as a colorant, the polyester resin and C.I. I Pigment Blue 15: 3
And a product obtained by subjecting the polyester resin and the polyester resin to C. The high-concentration pigment pellets prepared by heating and melting a dry pigment of I Pigment Blue 15: 3 and mixing them while applying a high shearing force are used. The full-color toner composition described. 10. The yellow toner comprises the polyester resin and C.I. C. I. Pigment Yellow 180 and the polyester resin and C.I. The high-concentration pigment pellets produced by heating and melting the dry pigment of I Pigment Yellow 180 and mixing while applying a high shearing force are used.
The full-color toner composition according to any one of 1. 11. A process of forming a latent image on a latent image carrier,
A step of developing the latent image with a developer of a plurality of colors,
A full-color image forming method for forming a toner image of a plurality of colors, wherein the developer contains the full-color toner composition according to any one of claims 1 to 10.