JP2000003071A - Image forming method using multicolor toner, toner and production of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method by which difference in temp., at which a hot offset of each color toner is caused, is decreased in a multicolored toner, to obtain a toner having improved durability and transfer property and having a small difference in durability and transfer property of each color toner, and to provide a producing method of the toner. SOLUTION: In the image forming method, a multicolor toner of yellow(Y), magenta(M), cyan(C) and black(Bk) toners each comprising at least a binder resin, pigment and releasing agent is used. The dispersion in the content ratio of the releasing agent present as domains (islands) in the resin of each color toner is within 20%. Further, the whole amt. of the releasing agent in the toner comprising at least a binder resin, pigment, releasing agent is 2 to 10 wt.%, and the proportion of the releasing agent present as domains in the resin is 2 to 7 wt.% of the whole toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a conventional melt-kneading,
The present invention relates to a multicolor toner for electrostatic charge development produced by a pulverization method and a method for producing the same. More specifically, the present invention relates to a toner having a small variation in hot offset occurrence temperature, durability, and transfer rate for each color in the multicolor toner, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Electrophotography generally utilizes a photoconductive substance, forms an electric latent image on a photoreceptor by various means, and then develops the latent image with a toner. After transferring the powder image to paper or the like, the powder image is fixed by heating or solvent vapor to obtain a copy. Magnetic brush method, cascade developing method, powder cloud method, etc. are known as methods for visualizing an electric latent image using toner, but fixing of toner image is an important step in any developing method. Needless to say. In particular, in the case of using a heat roller fixing machine, since the toner image and the heat roller come into contact with each other in a heated and melted state at the time of fixing, a so-called offset phenomenon in which a part of the toner image adheres to the heat roller surface and is transferred does not occur. Is required.

Conventionally, to prevent offset, the surface of the fixing roller is formed of a material having excellent releasability (such as silicone rubber or fluorine resin) from toner, and the surface of the fixing roller is prevented from offset and the surface of the roller is subjected to fatigue. To prevent this, the roller surface is coated with a thin film of a highly releasable liquid such as silicon oil or fluorine oil.
Although this method is extremely effective in preventing toner offset, it requires a device for supplying an anti-offset liquid, and thus has a problem that a fixing device becomes complicated. The application of the oil causes separation between the material layers constituting the fixing roller, and consequently has an adverse effect of shortening the life of the fixing roller.

In view of this, instead of using an oil supply device, an anti-offset liquid is supplied from the toner particles during the heating and pressurizing and fixing, so that a release agent such as a low molecular weight polyethylene or a low molecular weight polypropylene is added to the toner particles. Methods for adding agents have been proposed. In this way,
It is possible to prevent offset during heating and fixing, but on the other hand, these release agents are released from the toner and adhere to carriers and other charging members, causing a spent phenomenon that lowers the charging ability. It is known that the durability of the developer decreases. Furthermore, it is known that the presence of these release agents deteriorates the fluidity of the toner and deteriorates the transferability to paper.

In order to prevent toner particles from developing on a developing sleeve and a photoreceptor, prevent spent on a carrier, and prevent toner from sticking to a blade, the state of a conventional toner and the state of a release agent added to the toner The following proposals have been made to define For example, JP-A-3-2439
Japanese Patent Publication No. 56-56 proposes a toner using a toner having an average lattice length of the primary peak of small-angle X-ray scattering of the toner of 200 to 5000 °. Form a sea-island structure, and the maximum diameter of the island-shaped portion formed by the polypropylene in the major axis direction is 200 to 3000 °.
A toner having an average distance between islands of 1 μm or less has been proposed. Japanese Patent Application Laid-Open No. 5-45925 discloses a toner having a difference between a melting start temperature and a melting end temperature of a release agent of 50 ° C. or less and a melting point of 60 ° C.
-180 ° C release agent on the toner surface
Has been proposed.

In order to maintain developability and photoreceptor abrasion resistance, Japanese Patent Application Laid-Open No. Hei 5-197199 discloses that 2-20% of a polyolefin dispersed with a dispersed particle diameter of 0.01 to 0.5 μm on the toner surface. Containing toner has been proposed,
Further, Japanese Patent Application Laid-Open No. 7-301951 proposes a toner in which the difference in SP value between the binder resin and the release agent is 1.5 or less, and Japanese Patent Application Laid-Open No. 7-271095 discloses a crystallinity degree in the toner. Is in the range of 40 to 60%.

However, these conventional techniques are all effective in preventing spent and improving durability in a single toner. However, when these techniques are used for toners of a plurality of colors, hot offset is generated for each color. Temperature, durability,
There is a big problem that the toner having different characteristics such as the transfer rate is obtained.

[0008]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide an image forming method for a multicolor toner in which the difference between hot offset occurrence temperatures of each color toner is reduced. It is a second object of the present invention to provide a toner having improved durability and transferability and a small difference in durability and transferability of each color toner, and a method of manufacturing the same.

[0009]

The inventors of the present invention have found that the reason why these characteristics differ for each color is the presence of a release agent in the toner. In particular, the resin has a domain (having a structure different from the surrounding phase) in the resin. By controlling the state of the release agent present as an island-shaped domain with an interface with the surroundings, it has been found that toner having the same characteristics can be obtained.

That is, the above-mentioned problem is solved by the present invention comprising (1)
“Yellow (Y), magenta (M), cyan (C), black (B) comprising at least a binder resin, a pigment, and a release agent.
k) an image forming method using a multicolor toner, wherein the variation in the content of the release agent present as a domain (island) in the resin of each color toner is within 20%. Is achieved.

Further, in the present invention, (2) in the toner comprising at least a binder resin, a pigment and a release agent, the total amount of the release agent present in the toner is 2 to 10% by weight, and (3) (3) 75% of the release agent present as a domain in the resin, wherein the content of the release agent present as a domain is 2 to 7% by weight based on the total amount of the toner. The toner described in the above (2), wherein the maximum length of the above is 1 μm or less.
(4) "The release agent is composed of two or more types of release agents having different melting points, and the release agent present as a domain in the resin is the amount of the high melting point release agent> the low melting point release agent. The toner according to the above (2) or (3), "
(5) “Toner according to any one of the above (2) to (4), characterized by containing fine particles incompatible with the binder resin”, (6) “The binder resin is a polyester (2) characterized in that it is a resin or a polyol resin.
To (5). "

Still further, (7) the present invention relates to "(7) the method in which the releasing agent is previously absorbed / absorbed in the pigment or the fine particles according to claim 5, and then, together with the remaining releasing agent, the binder resin, and the charge controlling agent. Kneading, the method according to any one of the above (2) to (6). " In the present invention, "the dispersion of the content of the release agent is 2
“0%” is the ratio of the area of the release agent present in the resin in the cross section of the toner, and this is the ratio of each toner (yellow,
(Magenta, cyan, etc.) means that the difference in the area of the release agent between the maximum toner and the minimum toner is within 20%. Further, “75% of the release agent present as a domain” means that it is 75% of the number of particles of the release agent.

Hereinafter, the present invention will be described with reference to the drawings. According to FIG. 1, the release agent in the toner is dispersed and compatible at the molecular level in the resin with the one that is present in a state of being absorbed by the one that exists as a solid, such as a pigment or a charge control agent. Some exist as island domains with an interface in the resin. These differences can be easily determined from the fact that although they cannot be observed on the image obtained by the transmission electron microscope, the release agent present as a domain can be observed.

Most of the hot offset occurrence temperature is determined by the release agent existing as a domain in the resin, and the release agent hardly functions.
In the case of a plurality of color toners, since the type and amount of the pigment are different for each color, the amount of the release agent is different, and as a result, the amount of the release agent is different. Many pigments aggregate and combine nano-level particles to form primary particles at the submicron level, so the absorption of the release agent is large, and this difference in the amount of release agent is spurred. I will put it. For example, even if the prescription amount of the release agent is the same and the toner manufacturing method is the same, the state of the release agent in the resulting toner may be different as shown in FIG. 2, for example. .

That is, as shown in FIG. 2, when a transmission electron microscope image of a toner of a plurality of colors to which the method of the present invention is not applied is observed, even if the amount of the release agent and the manufacturing method are the same, the release of It can be seen that the molding agents differ in the total area ratio and the dispersed particle size. Furthermore, since the release agent also affects the durability and transferability, the fact that this amount differs for each color means that the toner in each color has different durability and transferability, and the finished image is poor. turn into.

That is, the amount of the release agent is determined in consideration of the amount of the release agent for the toners of a plurality of colors.
It is necessary to reduce the variation in the amount of the release agent and control the domain formation in the toner in the state shown in FIG. In the present invention, if the release agent present as a domain (island) in the toner of each color, that is, the toner resin, is within 20%, preferably within 15%, and more preferably within 10%, the variation in offset resistance is reduced. Discovered less. If this variation exceeds 20%, the offset resistance differs for each color. here,
The variation of 20% means that the content of the release agent present as a domain in the resin is ± 10% with respect to the average value of each color toner.
%. The content of the release agent present as a domain is determined by dispersing and dissolving the toner in a solvent that melts the binder resin but does not melt the release agent, for example, THF (tetrahydrofuran), and transmits the solution in a non-dried state using a transmission electron microscope. Is the value obtained by calculating the area ratio from the toner cross-sectional image.

The reason will be described below. It is desirable that the toners that fix a plurality of colors at the same time have the same fixing release characteristics. Therefore, the components other than the dyes and pigments are usually the same in material type and amount. However, if the pigments have different charging capacities, the type and amount of the charge control agent may be adjusted for each color so that the same charging capacity may be obtained. However, even with the toner configured as described above, the hot offset occurrence temperature of each color toner is different. This is nothing but the difference in the state of the release agent in the toner that determines the hot offset occurrence temperature.

In each toner, the total amount of the release agent present in the toner is 2 to 10% by weight, and the amount of the release agent is determined by the area ratio obtained from the cross-sectional image of the transmission electron microscope. 2 to 7%, preferably 3 to 6%,
More preferably, by setting the content to 3 to 4%, the hot offset occurrence temperature can be made the same, and the effective range can be controlled to a large range. When the area ratio of the release agent is less than 2%, it is difficult to prevent hot offset, which is the purpose of the release agent, in a high temperature range, and when it is more than 7%, the amount of the release agent present on the toner surface increases. And the degree of agglomeration and the transfer rate tend to decrease. Further, since the spent is easily generated, the durability of the developer is reduced.

Furthermore, by setting the maximum size of the release agent of 75% or more to 1 μm or less, the durability can be greatly improved. If the maximum length exceeds 1 μm, the same adverse effect as when the amount of the release agent is increased is caused. The maximum length of the dispersed particle size is determined by dissolving the obtained toner in a THF solvent at an arbitrary concentration and observing and measuring the dried toner with an optical microscope in a non-dried state. Two or more types of release agents having different melting points may be used,
In this case, it is desirable that the amount of the release agent is such that the amount of the high melting point release agent> the amount of the low melting point release agent. This is because, as the release agent has a higher melting point, the dispersion particle size can be reduced by kneading, and the durability is improved.

As the releasing agent, low molecular weight polypropylene, low molecular weight polyethylene, carnauba wax and the like are suitable. Candelilla wax, rice wax,
Natural waxes such as montan wax, low molecular weight polyolefins, higher fatty acids such as stearic acid, palmitic acid and myristic acid, metal salts of higher fatty acids, and higher fatty acid amides can also be used.

In order to control the amount and dispersion particle size of the release agent, a method of adding fine particles incompatible with the binder resin to the toner is used in addition to the method of changing the formulation amount of the release agent itself. You can also. By adding an appropriate amount of such fine particles to the toner, the amount of the release agent can be controlled.

The toner of the present invention can be produced by a usual method, that is, a method in which raw materials are mixed and then melt-kneaded by a kneading machine. It is possible to efficiently manufacture the toner of the present invention by producing the toner of the present invention by kneading it together with the rest of the releasing agent and the binder resin after absorbing it into the toner. With such a production method, a toner having less variation can be produced under high productivity conditions by absorbing a release agent in advance.
Examples of the fine particles having such characteristics include various metal oxide fine particles, ceramic fine particles, and metal fine particles. The fine particles are colorless or white so that the hue and transparency are not impaired, and the primary particle size is 0.1 μm.
The following are used:

For example, as the metal oxide fine particles, Si,
Ti, Al, Mg, Ca, Sr, Ba, In, Ga, N
i, Mn, W, Fe, Co, Zn, Cr, Mo, Cu,
Examples thereof include oxides such as Ag, V, and Zr and composite oxides.
Ceramic particles include SiC, Si ₃ N ₄ , Ti
C, TiN, WC, Sialon and the like. Among them, fine particles of silicon dioxide (silica), titanium dioxide (titania), and alumina are preferably used. further,
In order to effectively absorb oil, it is effective to perform a surface modification treatment with a hydrophobizing agent or the like. The following are typical examples of the hydrophobizing agent.

Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyl Trichlorosilane, chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane,
Vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl-trichlorosilane,
Decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane,
Dibentyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl-dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4
-T-butylphenyl) -octyl-dichlorosilane,
Dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di-3,3-dimethylbenzyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane, dioctyl-methyl-chlorosilane, Octyl-dimethyl-chlorosilane, (4-t-propylphenyl)
-Diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane, hexatolyldisilazane and the like. In addition, titanate-based coupling agents and aluminum-based coupling agents can also be used.

Hereinafter, other toners according to the present invention will be described in more detail. Conventionally known binder resins can be widely used. For example, styrene, parachlorostyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, -n- (meth) acrylate Butyl,
Isobutyl (meth) acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Lauryl (meth) acrylate, (meth) acrylic acid-2
-Hydroxyethyl, hydroxypropyl (meth) acrylate, (meth) acrylic acid-2-ethyl, (meth) acrylonitrile, (meth) acrylamide, (meth) acrylic acid, vinyl methyl ether, vinyl ethyl ether, vinyl Polymers of monomers such as isobutyl ether, vinyl methyl ketone, N-vinyl pyrrolidone, N-vinyl pyridine, butadiene,
Copolymers composed of more than one kind or mixtures thereof are mentioned. In addition, polyester, polyurethane, polyamide, epoxy resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin and the like can be used alone or in combination. Among them, a polyester resin or a polyol resin is suitable for controlling the dispersion state of the release agent.

The following are used as the pigment used in the present invention. Examples of the black pigment include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides. Examples of the yellow pigment include cadmium yellow, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hanza yellow G, Hanza yellow 10G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, tartrazine lake and the like. Can be As the orange pigment, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange R
K, benzidine orange G, indanthrene brilliant orange GK and the like. Red pigments include red, cadmium red, permanent red 4R,
Lithol Red, Pyrazolone Red, Watching Red Calcium Salt, Lakelet D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B and the like. Examples of purple pigments include Fast Violet B and Methyl Violet Lake. Examples of the blue pigment include cobalt blue, alkali blue, Victoria Blue Lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, and indanthrene blue BC. Green pigments include chrome green, chromium oxide, pigment green B, malachite green lake, and the like. These can be used alone or in combination of two or more.

Examples of the charge control agent include nigrosine, an azine dye having an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. Sho 42).
-1627), basic dyes (for example, CIBasic
Yello 2 (CI41000), CIBasic Yello 3, CIBasic R
ed 1 (CI45160), CIBasicRed 9 (CI42500), CIBa
sic Violet 1 (CI42535), CIBasic Violet 3 (CI42
555), CIBasic Violet 10 (CI45170), CIBasic Vi
olet 14 (C.1.42510), CIBasic Blue 1 (CI42025),
CIBasic Blue 3 (CI51005), CIBasic Blue 5 (CI
42140), C.1.Basic Blue 7 (CI42595), C.1.Basic Blu
e 9 (CI52015), C.1.Basic Blue 24 (CI52030), CI
Basic Blue 25 (CI52025), CIBasicBlue 26 (CI440
45), CIBasic Green 1 (CI42040), CIBasic Green
4 (CI42000) such as these basic dye lake pigments, CISolvent Black 8 (CI26150), benzoylmethyl-hexadecyl ammonium chloride, quaternary ammonium salts such as decyltrimethyl chloride, or dialkyltin compounds such as dibutyl or dioctyl, Polyamine resins such as dialkyltin borate compounds, guanidine derivatives, vinyl polymers containing amino groups, condensation polymers containing amino groups, and JP-B-41-20153.
Gazette, Japanese Patent Publication No. 43-27596, Japanese Patent Publication No. 44-
Metal complex salts of monoazo dyes described in JP-B-6397 and JP-B-45-26478;
No. 2752, JP-B-59-7385, etc., metal complexes of salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acids such as Zn, Al, Co, Cr, Fe, etc., and sulfonated copper phthalocyanine pigments Is mentioned. The ratio of binder resin to the total toner is 75
~ 93%, colorant 1.5 ~ 10%, release agent 2 ~ 10
% And other components are 1 to 7%.

In order to improve fluidity, developability and transferability,
After kneading and pulverizing as a toner, it is also possible to externally add hydrophobic fine powder such as silica, titanium oxide, and alumina to the toner. When the toner of the present invention is used as a two-component developer, it is used by mixing with a carrier powder. As the carrier in this case, known carriers can be widely used, and examples thereof include iron powder, ferrite powder, magnetite powder, nickel powder, glass beads, and the like, and those obtained by coating these surfaces with a resin or the like. . Generally, the mixing ratio of the toner and the carrier is
The appropriate amount of toner is about 0.5 to 6.0 parts by weight with respect to parts by weight.

As a device for kneading the toner, a batch-type twin-hole screw, a Banbury mixer or a continuous-type twin-screw extruder, for example, a KTK type twin-screw extruder manufactured by Kobe Steel, Ltd.
TEM twin screw extruder manufactured by Toshiba Machine Co., KCK twin screw extruder, PCM twin screw extruder manufactured by Ikegai Iron Works Co., Ltd. KEX twin screw extruder manufactured by Kurimoto Iron Works Co., Ltd., and continuous single screw kneader ,
For example, a co-kneader manufactured by Buss Corporation is preferably used. The melt-kneaded material obtained as described above is subsequently pulverized. For the pulverization, for example, coarse pulverization is performed using a hammer mill or the like, and further a fine pulverizer using a jet stream can be used. It is desirable that the pulverization is performed so that the average particle size becomes 3 to 15 μm. Further, the size of the pulverized product is adjusted to 5 to 20 μm by an air classifier. The color image in the present invention can be obtained by either the Y, M, C, or Bk color transfer in order for each color, or the so-called intermediate transfer method in which each color is transferred once after transfer.

[0030]

EXAMPLES Next, the present invention will be described more specifically with reference to examples and comparative examples. However, these examples are only one embodiment of the present invention, and the present invention is limited to the contents of these examples. It is not something to be done. The parts here are based on weight. Example 1 The binder resin, the pigment, and the charge control agent are common to each color. Yellow toner polyester resin 100 parts Disazo yellow pigment (CI Pigment Yellow 17) 5 parts Chromium-containing azo dye 2 parts Magenta toner polyester resin 100 parts Quinacridone-based magenta pigment (CI Pigment Red 122) 4 parts Chromium-containing azo dye 2 parts Cyan toner polyester resin 100 parts Copper phthalocyanine blue pigment (CI Pigment Blue 15) 2 parts Chromium-containing azo dyes 2 parts Black toner polyester resin 100 parts Carbon black (Mitsubishi Chemical C.44) 6 parts Chromium-containing azo dyes 2 parts Use the ones shown for each color.

[0031]

[Table 1]

After the above materials were sufficiently mixed in a blender for each color, they were melted and kneaded at a kneaded material temperature of 120 ° C. by a twin screw extruder. The kneaded material was rolled and cooled, coarsely pulverized with a cutter mill, and pulverized with a fine pulverizer using a jet stream, and then, using an air classifier, mother colored particles of each color were obtained. Further, with respect to 100 parts by weight of the base colored particles, 0.5 parts by weight of hydrophobic silica was mixed with a Henschel mixer, and yellow,
Magenta, cyan, and black toners were obtained. Table 2 shows the results of measuring the volume average particle diameter of the obtained toner, the size of the domain of the release agent, and the maximum length of the dispersed particle diameter.
(The volume average particle diameter is measured by a Coulter Counter Model TA-II manufactured by Coulter Electronics Co., Ltd. The release agent amount is an area ratio obtained by image analysis from a cross-sectional image of a transmission electron microscope. Approximately 20 mg of the obtained toner was dissolved in about 0.2 g of a THF solvent, and observed and measured with an optical microscope at a magnification of 500 times in a non-dried state.)

[0033]

[Table 2] Variation in release agent amount = ((maximum amount-minimum amount) / average amount)
× 100

A carrier 100 obtained by coating the toner with a ferrite particle having an average particle diameter of 50 μm and a silicon resin on the surface thereof
5 parts by weight with respect to parts by weight were mixed with a turbuler mixer to obtain yellow, magenta, cyan and black developers. The obtained developer was set in a pre-tail 550 manufactured by Ricoh Co., Ltd., and a running test of 100,000 sheets was performed in a state where no oil was set in the fixing device.
Offset resistance, durability, and transferability were evaluated for each color. Table 16 shows the results.

Evaluation method [Offset resistance] Check the offset occurrence temperature [Durability] Evaluated by the change in the charge amount of the developer at the start of the running test and after copying 100,000 sheets. [Transferability] Toner at the time of copying 10,000 sheets The transfer rate was determined from the consumed amount and the amount of toner collected by the cleaning device, and evaluated. The variation for each color was calculated by the difference between the maximum value and the minimum value under each evaluation condition. [Example 2]

[0036]

[Table 3]

The above raw materials were treated in the same manner as in Example 1 to obtain toners shown in Table 4. Further, the same processing as in Example 1 was performed to obtain each color developer. Next, the obtained developer was evaluated for image formation in the same manner as in Example 1. Table 16 shows a list of the evaluation results.

[0038]

[Table 4] [Example 3]

[0039]

[Table 5]

When the above raw materials are kneaded, the temperature of the kneaded material is set at 105.
Table 6 was treated in the same manner as in Example 1 except that
Was obtained. Further, the same processing as in Example 1 was performed to obtain each color developer. Next, the obtained developer was evaluated for image formation in the same manner as in Example 1. Table 16 shows a list of the evaluation results.

[0041]

[Table 6] [Example 4]

[0042]

[Table 7]

The above raw materials were treated in the same manner as in Example 3 to obtain toners shown in Table 8. Further, the same processing as in Example 3 was performed to obtain each color developer. Next, the obtained developer was evaluated for image formation in the same manner as in Example 3. Table 16 shows a list of the evaluation results.

[0044]

[Table 8] [Example 5]

[0045]

[Table 9]

The above raw materials were treated in the same manner as in Example 3 to obtain toners shown in Table 10. Further, the same processing as in Example 3 was performed to obtain each color developer. Next, the obtained developer was evaluated for image formation in the same manner as in Example 3. Table 16 shows a list of the evaluation results.

[0047]

[Table 10] Example 6 Using the same raw materials as in Example 5, first, a pigment, hydrophobic silica, and a release agent were mixed by a mixer, and then heated at 100 ° C. for 30 minutes in a thermostatic oven to absorb the release agent. A kneaded material 1 was obtained. Next, the kneaded material 1 and other raw materials were mixed by a mixer, and the mixture was treated in the same manner as in Example 5 to obtain a toner shown in Table 11. Further processing was performed in the same manner as in Example 3 to obtain each color developer. Next, the obtained developer was evaluated for image formation in the same manner as in Example 3. Table 16 shows a list of the evaluation results.

[0048]

[Table 11] [Comparative Example 1]

[0049]

[Table 12]

The above raw materials were treated in the same manner as in Example 1 to obtain toners shown in Table 13. Further processing was performed in the same manner as in Example 1 to obtain each color developer. Next, when the obtained developer was evaluated for image formation in the same manner as in Example 1, the characteristic values of each color were different. In particular, the cyan toner was remarkably inferior in offset resistance, durability and transfer rate, and could not satisfy the standard values. Table 16 shows a list of the evaluation results.

[0051]

[Table 13] [Comparative Example 2]

[0052]

[Table 14]

The above raw materials were treated in the same manner as in Example 1 to obtain toners shown in Table 15. Further processing was performed in the same manner as in Example 1 to obtain each color developer. Next, when the obtained developer was evaluated for image formation in the same manner as in Example 1, the characteristic values of each color were different. In particular, the yellow toner and the black toner have very good durability and transfer rate, but hardly have offset resistance and releasability. Table 16 shows a list of the evaluation results.

[0054]

[Table 15]

[0055]

[Table 16]

[0056]

As described above, according to the present invention, the difference between the hot offset occurrence temperatures of the toners of the respective colors in a toner which simultaneously fixes a plurality of colors, such as a full-color toner, is reduced. can do. Further, it is possible to greatly improve the durability and the transferability, and to obtain a toner having a small difference.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a toner by a transmission electron microscope.

FIG. 2 shows a toner cross-sectional image of a conventional toner by a transmission electron microscope.

FIG. 3 shows a cross-sectional image of the toner of the present invention by a transmission electron microscope.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoichiro Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Keiko Shiraishi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Inside the company Ricoh

Claims (7)

[Claims] 1. Yellow (Y), magenta (M), cyan (C) comprising at least a binder resin, a pigment and a release agent.
An image forming method using a black (Bk) multicolor toner, wherein the variation in the content of the release agent present as a domain (island) in the resin of each color toner is within 20%. . 2. A toner comprising at least a binder resin, a pigment, and a release agent, wherein the total amount of the release agent present in the toner is 2 to 10% by weight, and the release agent is present as a domain in the resin. Is 2 to the total amount of the toner.
7% by weight. 3. The toner according to claim 2, wherein the maximum length of 75% or more of the release agent present as a domain in the resin is 1 μm or less. 4. The release agent is composed of two or more types of release agents having different melting points, and the amount of the release agent present as a domain in the resin is such that the amount of the high melting point release agent> the low melting point release agent The toner according to claim 2, wherein the toner amount is an agent amount. 5. The toner according to claim 2, further comprising fine particles incompatible with the binder resin. 6. The toner according to claim 2, wherein the binder resin is a polyester resin or a polyol resin. 7. A method in which a releasing agent is previously absorbed / absorbed in a pigment or fine particles according to claim 5, and then kneaded together with the remaining releasing agent, binder resin and charge controlling agent. Item 7. The method for producing a toner according to any one of Items 2 to 6.