JP3429610B2 - Multicolor electrophotography - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method by multicolor electrophotography. The present invention also relates to improvement of the developing method in the image forming method, and this developing method is applied not only to multicolor but also to monochromatic electrophotographic image forming methods.

[0002]

2. Description of the Related Art To obtain a multicolor image by electrophotography, generally, toners of three colors of yellow, magenta, and cyan are used, and toner images of respective colors are superposed and mixed. However, in the case of color toner,
The following characteristics peculiar to color toners, which are different from conventional black toners, are required, and there are the following problems.

The electrophotographic method adopted in a copying machine, a laser printer or the like is generally such that a uniform electrostatic charge is applied on a photoconductive insulating layer and a light image is irradiated on the insulating layer. To partially remove the electrostatic charge to form an electrostatic latent image, and to attach a fine powder called toner to the portion where the electrostatic charge remains to form the visualized toner image of the latent image (called development). Then, the toner image is heated and fixed on the recording paper to obtain a printed matter.

Although various fixing methods are known as the fixing method, a rotatable heat roller having a built-in heat source for reasons such as particularly high thermal efficiency and no risk of fire,
A heat roller fixing method including a pressure roller that rotates while being in contact with the heat roller has been widely put into practical use, and an aluminum roller is generally used as the both rollers. However, when the aluminum roller is used, the hardness is high, so the surface of the fixed image becomes rough and the smoothness is inferior after the toner is melted by heat. Occurs, and there is a problem that the image quality is inferior. Further, it is remarkable in printing an image such as a natural image using a color toner, and a high smoothness of a fixed image has been desired. To improve the smoothness of the fixed image,
Although it is desirable to use silicone rubber or the like as the roller material to reduce the roller hardness, when silicone rubber is used, the surface of the silicone rubber is easily scraped due to contact with toner, paper, etc., the surface of the roller is rough, and the life is short. There was a flaw. Also, in order to improve the durability of only the roller surface without significantly lowering the hardness of the roller, if a roller coated with fluorocarbon resin on silicone rubber is used as the fixing roller, the durability is improved while maintaining good image smoothness. It is possible to improve. However, there is a problem that the offset is likely to occur and the fixing temperature margin is narrowed. In particular, in the color toner in which the image smoothness is important, since the viscoelasticity of the toner is low, there is a problem that offset is more likely to occur as compared with the conventional black toner.

As a binder resin for color toner, a polyester resin is generally used because it has a small refractive index. In particular, a polyester resin having a linear structure has a low viscoelasticity, so that the surface of the fixed image is fixed. Because of its excellent smoothness, it was the mainstream as a binder resin for color toner. However, when the linear polyester resin is used, the fixing property with the soft roller is good, but when the fixing is performed with the semi-soft roller used in the high-speed color printer, there is a problem that the offset resistance is poor. On the other hand, in order to improve the offset resistance, the polyester resin containing a gel component can improve the offset resistance, but there is a problem that the fixed image cannot be smoothed. As described above, there has been no binder resin for color toner that can achieve both offset resistance and smoothness of the fixed image surface.

Further, the heat roll fixing device has widely been put to practical use as a heat roller fixing system comprising a rotatable heat roller having a built-in heat source and a pressure roller rotating while being in contact with the heat roller. Was commonly used. However, when the aluminum roller is used, the hardness is high, so the surface of the fixed image becomes rough and the smoothness is inferior after the toner is melted by heat. Occurs, and there is a problem that the image quality is inferior. further,
This is remarkable in the printing of images such as natural images using color toner, and high smoothness of fixed images has been desired. In order to improve the smoothness of the fixed image, it is desirable to use silicone rubber or the like as the roller material to reduce the roller hardness.However, when silicone rubber is used, the roller surface may be abraded by contact with toner or paper. Since the roller surface is rough, the roller surface is rough, and the life is short, it is difficult to put it into practical use in a high-speed printer because the replacement cycle is short. Also, in order to improve the durability of only the roller surface without significantly lowering the hardness of the roller, if a roller coated with fluorocarbon resin on silicone rubber is used as the fixing roller, the durability is improved while maintaining good image smoothness. It is possible to improve. However, the offset resistance was poor, and it was necessary to improve the offset resistance from the toner side. However, the conventional toner with improved offset resistance is inferior in image smoothness in soft roller fixing, and while maintaining good smoothness in soft roller fixing,
In a semi-soft roller fixing machine, there is no color toner that can realize good offset resistance.

A first object of the present invention is to realize good smoothness and offset resistance in this semi-soft roller fixing machine. In the case of color toner, the following characteristics peculiar to color toner that are different from conventional black toner are required,
There are the following problems. Benzidine-based pigments have been mainly used as a pigment for yellow toner. However, benzidine-based pigments may generate a carcinogenic substance (dichlorobenzidine) at high temperature (200 ° C.) and have another structure. ,
When a safe pigment such as isoindolinone-based pigment or benzimidazolone-based pigment is used, the color developability is poor, and
There has been a problem that the toner charge amount greatly changes during continuous printing, and stable developability cannot be obtained.

When a quinacridone pigment, a naphthol pigment, or an azo lake pigment is used as the magenta pigment, the color developability is good, but the toner charge amount fluctuates greatly during continuous printing, and stable developability cannot be obtained. was there.
Similarly, when a copper phthalocyanine pigment is used as the cyan pigment, good color developability can be obtained, but there is a problem that the toner charge amount varies greatly during continuous printing and stable developability cannot be obtained.

The cause of each of the above problems is that the pigment particles in the toner are large, so many pigments are exposed on the toner surface,
This is because the toner filming on the surface of the carrier by this pigment is inferior in continuous printability, and since the pigment particles are large, the transparency is poor and vivid color development cannot be obtained. Furthermore, in the case of color electrophotography, when the amount of adhered color toner (developed amount) changes, the color tone of the printed matter changes greatly. Therefore, in the case of color toner, after continuous printing,
It is indispensable to realize a stable development amount even when the environment changes, and there is a problem that stable printing characteristics cannot be obtained in the color developer whose charge amount changes as described above.

As a conventional charge control agent for color toner, a metal complex such as a chromium complex or a zinc complex is generally used and has a good charge imparting effect, but the metal complex will be regulated in the future due to environmental problems and the like. There is a strong desire to change to a metal-free charge control agent because it may become a target. However, the resin charge control agent has a small charging effect, and the calixarene compound also has a problem that the charging effect is small when used in a general color toner in a usual method. An effective colorless charge control agent has never existed before.

As external additives for color toners, there are hydrophobic silica powder, titanium dioxide powder and the like. The hydrophobic silica powder has a great effect of improving the fluidity of the toner, but the charge amount due to environmental changes (especially humidity changes). Increase the change. On the other hand, titanium dioxide powder has the effect of reducing the change in charge due to environmental changes, but has a small effect of improving the fluidity of the toner. Further, although the mixture of the hydrophobic silica powder and the titanium dioxide powder has the effect of improving the fluidity, there is a problem that the change in the amount of charge due to the environmental change cannot be reduced.

As described above, there has been no color developer capable of realizing all of the excellent color forming properties, the charging stability due to environmental changes, and the image stability during continuous printing in the color toner. Furthermore, when a highly safe benzimidazolone-based pigment is used as the yellow pigment, the hue shifts in the reddish direction as compared with a general-purpose benzimidazolone-based pigment,
When a general general-purpose quinacridone pigment is used as the magenta pigment, there is a problem that the color balance is disturbed.

A second object of the present invention is to provide an image forming method capable of stably supplying a vivid full color image for a long period of time even if environmental conditions change.

[0014]

First Aspect (Toner Binder Resin) A first object of the present invention is to provide, in the first aspect of the present invention,
An image forming method by a multicolor electrophotographic method, which comprises a step of heat fixing using a semi-soft roller having a roller base material surface coated with a silicone rubber having a thickness of 2 to 30 mm and a surface coated with a fluororesin, The binder resin of the color toner is composed of an alcohol component and an acid component, the alcohol component is a dihydric alcohol, and the acid component is a polycarboxylic acid and the following general formula:

[0015]

[Chemical 4]

(In the formula, R ¹ , R ² and R ³ have 6 to ² carbon atoms.
4 preferably 10 to 20, especially about 12 saturated or unsaturated hydrocarbon groups) and a polyester resin comprising at least one selected from the divalent carboxylic acids and their anhydrides. This is accomplished by providing a method for forming images by multicolor electrophotography. In a binder resin used for a color toner for forming an image on a heat roll fixing device by a multicolor electrophotographic method, the binder resin comprises an alcohol component and an acid component, the alcohol component is a dihydric alcohol, and the acid component is Is a polyvalent carboxylic acid and general formulas (1), (2) (wherein R ¹ ,
R ² and R ³ are each a saturated or unsaturated hydrocarbon group having 6 to 24 carbon atoms) and a polyester resin composed of a divalent carboxylic acid or an anhydride thereof is used as a binder resin for a color toner, (I) and formula (I
The monomers represented by I) form long side chains, and the long side chains are entangled with each other without binding to each other to form a pseudo crosslinked structure. The entanglement of the side chains makes it possible to optimize the dynamic viscoelasticity of the toner, and realizes good image smoothness in soft roll fixing and good offset resistance in semi-soft roller fixing.

Furthermore, by using terephthalic acid or its anhydride as the polyvalent carboxylic acid, it becomes easy to optimize the dynamic viscoelasticity of the toner. Further, by using trimellitic acid or its anhydride as the polycarboxylic acid, it becomes easy to optimize the dynamic viscoelasticity of the toner. Use of the divalent alcohol represented by the following general formula (III) facilitates optimization of the dynamic viscoelasticity of the toner.

[0018]

[Chemical 5]

(Wherein R ³ is an alkylene group having 2 to 4 carbon atoms, and the average value of the sum thereof is 2 to 16) Furthermore, 2 represented by the above formula (I) or (II) Carboxylic acid or its anhydride is 10 mol% in the acid component
In the following cases, the effect of pseudo-crosslinking does not appear and the offset resistance is poor in a semi-soft roller fixing machine. When the amount of the divalent carboxylic acid represented by the formula (I) or the formula (II) or the anhydride thereof is 80 mol% or more in the acid component, the image smoothness in the soft roll fixing device is poor. When the chloroform insoluble content of the polyester resin is 20 wt% or more in the polyester resin, the dynamic viscoelasticity becomes too high and the image smoothness in the soft roll fixing device becomes poor.

Even if the polyester resin and the conventional linear polyester resin are mixed and used, good characteristics can be maintained. The toner used in the first aspect of the present invention is not limited, but the following are generally considered. The following color materials can be considered as the color toner.

Examples of the benzidine organic pigment used in the present invention include C.I. I. 21
090 (Pigment Yellow 12, KET Yellow 406, Dainippon Ink and Chemicals), C.I. I. 21095 (Pigment Yellow 14, KET Yellow 404, Dainippon Ink and Chemicals), C.I. I. 21100 (Pigment Yellow 13, KE
TYellow 405, Dainippon Ink and Chemicals). This pigment has excellent dispersibility in the binder resin, and
Good spectral reflection characteristics.

Examples of the quinacridone organic pigments used in the present invention include C.I. I. 73916
(Pigment Red 122, KET Red 309, Dainippon Ink and Chemicals). The pigment has excellent dispersibility in a binder resin and good spectral reflection characteristics. The rhodamine-based organic pigment used in the present invention has a color index
No. C. I. 45160 (Pigment Red 81, Ultr
a Rose R, Toyo Ink Mfg. Co., Ltd.). The pigment has excellent dispersibility in a binder resin and good spectral reflection characteristics.

Next, the phthalocyanine organic pigments used in the present invention include C.I. I. 7
4160 (Pigment Blue 15, KET Blue 102, KET Bl
ue 103, KET Blue 104, KET Blue 105, KET Blue 106,
KET Blue 111, Dainippon Ink and Chemicals), C.I. I. 74
260 (Pigment Green 7, KET Green 201, Dainippon Ink and Chemicals) and the like. The pigment has excellent dispersibility in a binder resin and good spectral reflection characteristics.

Further, a metal-containing dye, a fatty acid ester, or a compound having an amino group may be added as a charge control agent.
The toner used in the first aspect of the present invention can be manufactured by a conventionally known method. That is, the binder resin and the pigment, and if necessary, wax, a charge control agent, etc. are added, and the mixture is melt-kneaded and uniformly dispersed by, for example, a pressure kneader, an extruder, etc., for example, an air classifier or the like. Thus, the desired toner can be obtained by classification.

Second Aspect (Color Toner) The second object of the present invention is, in the second aspect of the present invention,
Three colors of yellow toner, magenta toner, and cyan toner, which are composed of a binder resin, a charge control agent, a colorant, and an external additive,
Alternatively, in the image forming method in which an image is formed by heat roll fixing by a multicolor electrophotographic method using the three-color toner and the black toner, the yellow toner used as a colorant in the yellow toner is a benzimidazolone-based pigment. ,
Dispersed in the yellow toner with an average particle size of 1 μm or less,
And a toner using titanium dioxide powder surface-treated with a silane coupling agent as an external additive, wherein the magenta toner has a magenta pigment used as a colorant dispersed in the magenta toner with an average particle size of 1 μm or less, and A toner using titanium dioxide powder surface-treated with a silane coupling agent as an external additive, wherein the cyan toner has a cyan pigment used as a colorant dispersed in the cyan toner with an average particle size of 1 μm or less, and Provided is a toner using titanium dioxide powder surface-treated with a silane coupling agent as an external additive, and the charge control agent is a calixarene compound. It is achieved by

As a colorant used for color toner, by dispersing this in the toner with an average particle size of 1 μm or less, the color developability is improved, and further, the pigment is prevented from being exposed on the surface of the toner. When used as a developer, the occurrence of toner filming on the carrier surface was suppressed, and fluctuations in toner charge amount were reduced. Furthermore, by using titanium dioxide powder surface-treated with a silane coupling agent as an external additive, the environmental humidity is 20 to 80% RH.
Even when it fluctuated between (25 ° C.), the change in the toner charge amount could be reduced. Further, as a yellow pigment, by changing from a conventional benzidine-based pigment to a benzimidazolone-based pigment, there is no fear of carcinogenic substance generation, and also in a magenta toner, a naphthol-based azo pigment, or as a cyan pigment , Using a copper phthalocyanine pigment, and by using titanium dioxide powder surface-treated with silane coupling as an external additive,
Even when the environmental humidity fluctuated between 20 to 80% RH (25 ° C.), the change in the toner charge amount could be reduced. Furthermore, by using a calixarene compound as a charge control agent in a color toner in which a pigment is finely dispersed and TiO ₂ is used as an external additive, it is a material that does not contain a metal element and is highly safe, but at the time of continuous printing. The stable and good charging characteristics were realized also in.

The above yellow toner, magenta toner,
By using cyan toner, stable and vivid image formation is possible for a long period of time even when the environmental humidity changes and in continuous printing, and a color balance is obtained.
A color toner can be provided. The average particle diameter of primary particles as an external additive is 0.001 to 0.1 μm,
Further, by using titanium dioxide in which the average particle diameter of the titanium dioxide powder adhered to the toner surface is 1.0 μm or less, the effect of improving the fluidity of the toner is great, and other external additives are used. The combined use of can be eliminated.

As an external additive, electric resistance is 1 × 10 ⁶ to 1
By using a titanium dioxide powder of × 10 ¹² ,
It is possible to suppress the change in the electric resistance of the toner due to the environmental change and reduce the change in the toner charge amount. By using titanium dioxide powder of anatase type rather than rutile type as the external additive of the toner, the cause is unknown, but stable charge amount characteristics can be realized for a long period of time.

The titanium dioxide powder in which the silane coupling agent used as the coating agent is n-butyltrimethoxysilane has few primary particle associations and the secondary particles do not have a large particle size. Is big. When the amount of the titanium dioxide powder added is less than 0.1 wt% in the toner, the effect of the external additive is small and the charging property becomes poor. On the other hand, when the amount exceeds 2 wt%, toner scattering increases, which causes a problem of contaminating the inside of the apparatus.

The calixarene compound used in the second aspect of the present invention is

[0031]

[Chemical 6]

A compound represented by or a derivative thereof. As the derivative, a benzene ring, a methylene group, a hydrogen atom of a hydroxyl group or R is various substituents (especially lower alkyl,
Examples thereof include those substituted with aryl, aralkyl, halogen atoms, etc., and copolymers between such derivatives (see JP-A-2-201378). Further, if the addition amount of the charge control agent is less than 0.1 wt% in the toner, the effect of imparting charge is small and the charging characteristics are poor. On the other hand, if it exceeds 5 wt%, the charging stability becomes poor.

The toner used in the second aspect of the present invention can also be manufactured by a conventionally known method. That is, the binder resin and the pigment, and if necessary, wax, a charge control agent, etc. are added, and the mixture is melt-kneaded and uniformly dispersed by, for example, a pressure kneader, an extruder, etc., for example, an air classifier or the like. Thus, the desired toner can be obtained by classification.

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[Resin Production Example 1]

Polyoxypropylene (2,2) -2,2-bis (4-
Hydroxyphenyl) propane 680 g, terephthalic acid 120 g, tetraprophenylsuccinic anhydride 10
0 g and 0.1 g of hydroquinone were put into a flask, the temperature was raised to 220 ° C. using a mantle heater, and the reaction was carried out while stirring in a nitrogen stream. Next, trimellitic acid 2
0 g was added and reacted for about 6 hours to produce a polyester resin. The softening point was 115 ° C.

The method for producing the toner will be described below. [Toner 1 (Yellow)] Binder resin: Polyester resin of Production Example 1 93.5 parts by weight Coloring material: Benzimidazolone pigment, Pigment Yellow 154 4 parts by weight Charge control agent: BONTRON E84 (manufactured by Orient Chemical Co., Ltd.) 0.5 Parts by weight Wax: Viscole 660-P (manufactured by Sanyo Kasei) 2 parts by weight The above composition is mixed and stirred by a ball mill, melt-kneaded by an extruder heated to 140 ° C., cooled and solidified, and then coarsely crushed by a crusher, and further , Pulverized with a jet mill. The obtained fine powder is classified with an air classifier for 5 to 20
μm toner was obtained. As an external additive to the obtained toner,
The titanium dioxide powder was used in an amount of 1% by weight and externally added by a Henschel mixer.

As the toners of other colors, the yellow toner and the toner in which only the pigment was changed were experimentally manufactured. [Toner 2] Magenta Toner Pigment: Quinacridone Pigment Pigment Red 122 [Toner 3] Cyan Toner Pigment: Copper Phthalocyanine Pigment Pigment Blue 15

[0068]

[Table 1]

(Binder Resin Monomer Composition and Physical Properties) Monomer Composition / Alcohol Component (Dihydric Alcohol): Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propanoic Acid Component (2 Carboxylic acid): tetraprophenyl succinic anhydride [the carbon number of R ^{1 in} the formula (I) is 12] (polycarboxylic acid): terephthalic acid (divalent) (polycarboxylic acid): trimellitic acid ( Trivalent) Chloroform insoluble matter: 0 wt% The following printer was used as the evaluation apparatus of this example. [Multicolor Image Forming Apparatus (FIG. 1)] FIG. 1 shows an outline of an image forming apparatus in which a plurality of image forming units are arranged to output a multicolor image.

Reference numeral 1 is a photoconductor, and the charger shown in FIG. 2 uniformly charges the surface of the photoconductor. 3 is an exposure part,
Image light is projected onto the surface of the photoconductor in accordance with recorded information to form an electrostatic latent image on the surface of the photoconductor. Numerals 4, 5, 6, and 7 are developing portions, which visualize the electrostatic latent image formed on the photoconductor using toner. Incidentally, 4 is a yellow toner, 5 is a magenta toner, 6 is a cyan toner, and 7 is a developing device for developing a black toner. The developed toner image is conveyed on the paper conveyance belt 8 and is in contact with each photoconductor, so that the visible toner image on the photoconductor is given a charge having a polarity opposite to the charging direction of the toner from the back surface of the paper. The toner images are sequentially transferred onto the paper. Reference numeral 10 denotes a heat roll fixing device (details are shown in FIG. 2), which fixes the multicolor toner image transferred onto the paper by heating. Reference numeral 11 denotes a charge eliminating portion, which eliminates residual charges on the photoconductor by the LED light. Reference numeral 12 denotes a cleaning unit, which removes toner remaining on the photoconductor from the photoconductor. [Semisoft Roll Fixing Machine (FIG. 2)] The fixing device is composed of a heat roller 22 having a heater 21 built therein and a pressure roller 23.
Installed on both sides, heat roller and pressure roller are 2 kgf /
It is crimped at cm ² . The surface of the fixing roll is coated with perfluoroalkoxy resin 27 of 50 μm as a fluororesin, and the intermediate layer between the fluororesin and the aluminum roller has a thickness of 1 mm.
Silicone rubber 26 having a rubber hardness of 30 was used. The fixing oil was used by impregnating the felt 25 with the fixing roller under pressure. The surface temperature of the hot roll was controlled at 160 ° C. [ Example 1 ] The toners 1 to 3 were used, and the average particle size was 60 as a carrier.
A developer was prepared at a toner concentration of 5 wt% in combination with a ferrite carrier coated with a μm acrylic coat, and evaluated under the following evaluation conditions. i) Printer process speed: 100 mm / s ii) Number of prints: 150,000 sheets iii) Fixing roller / coated fluororesin: Perfluoroalkoxy resin / roll pressure: 2 kgf / cm ² · Fluorine resin coating thickness: 50 μm / Intermediate layer Rubber hardness: Rubber hardness 30 • Material of intermediate layer: Silicone rubber • Roller surface temperature: 170 ° C Evaluation was made according to the following evaluation criteria.

[0071]

[Table 2]

As a result, all the following characteristics were satisfied.・ Offset resistance: Up to 220 ℃, no offset occurs ・ Smoothness: Image glossiness of 18 can be achieved to achieve vivid full-color images. ・ Roller life: No deterioration of characteristics even after printing 150,000 sheets. The test results of the roll fixing machine are also shown. [Soft roll fixing machine (Fig. 3)] The fixing device is the heater 21.
It is composed of a heat roller 22 and a pressure roller 23, each of which has an attached spring 24 on both sides,
The heat roller and pressure roller are pressure bonded at 2 kgf / cm ² .
As the fixing roll, a roll having an aluminum roller surface coated with 20 mm of silicone rubber 26 was used. The fixing oil was used by impregnating the felt 25 with the fixing roller under pressure. The surface temperature of the hot roll was controlled at 160 ° C. (Evaluation conditions) Printer process speed: 30 mm / s Number of printed sheets: 20,000 sheets Fixing roller-Coated silicone rubber thickness: 20 mm-Roll pressure: 2 kgf / cm ² -Roller surface temperature: 170 ° C

[0073]

[Table 3]

As a result, the following characteristics were all satisfied. -Offset resistance: No offset occurs up to 220 ° C-Smoothness: A vivid full-color image can be realized with an image glossiness of 23-Roller life: No characteristic deterioration after printing 20,000 sheets [ Example 2 ] The toner In 1, 2, and 3, tetraprophenylsuccinic anhydride [the carbon number of R ^{1 in} the formula (I) is 12] is used as an acid component used as a monomer of the binder resin, and diprophenylsuccinic anhydride [(I) Was evaluated in the same manner as in Example 1 except that the number of carbon atoms in R ¹ of was changed to 6],
Similar to Example 1 , good characteristics could be realized. [ Example 3 ] In the toners 1, 2 and 3, tetraprophenylsuccinic anhydride [the carbon number of R ^{1 in} the formula (I) is 12] is octaprophenylsuccinic acid as an acid component used as a binder resin monomer. As a result of conducting an evaluation in the same manner as in Example 1 except that the anhydride [R ^{1 in} the formula (I) has 24 carbon atoms] was used, good characteristics were realized as in Example 1 . [Comparative Example 1] In the toners 1, 2, and 3, tetraprophenylsuccinic anhydride [the carbon number of R ^{1 in} the formula (I) is 12] is used as an acid component used as a monomer of the binder resin. Anhydrous [R ^{1 in} the formula (I) has 3 carbon atoms]
As a result of evaluation in the same manner as in Example 1 except that the offset was changed to, an offset occurred at 200 ° C. in the semi-soft roller fixing. [Comparative Example 2] In the toners 1, 2, and 3, tetraprophenylsuccinic anhydride [R ¹ of formula (I) has 12 carbon atoms] was used as an acid component used as a monomer of the binder resin. As a result of evaluation in the same manner as in Example 1 except that the acid anhydride [R ^{1 in} the formula (I) has 27 carbon atoms], the image smoothness was poor and a vivid full-color image could not be realized. [ Examples 4 to 26 , Comparative Examples 3 to 18] Further, Examples and Comparative Examples are summarized in the attached table.

[0075]

[Table 4]

[0076]

[Table 5]

[0077]

[Table 6]

[0078]

[Table 7]

[0079]

[Table 8]

Second Aspect The method for producing the toner will be described below. [Toner 11 (black)] Binder resin: Polyester resin (softening point 100 ° C.) 92 parts by weight Coloring material: Black Pearls L (Cabot) 4 parts by weight Charge control agent: BONTRON E81 (manufactured by Orient Chemical Co.) 2 parts by weight Wax: Viscole 660-P (manufactured by Sanyo Kasei) 2 parts by weight The above composition is mixed and stirred with a ball mill, melt-kneaded with an extruder heated to 140 ° C., cooled and solidified, then coarsely pulverized with a pulverizer, and further jet-milled. Finely crushed. The obtained fine powder is classified with an air classifier for 5 to 20
μm toner was obtained. [Toner 12 (Yellow)] Binder resin: Polyester resin (softening point 100 ° C.) 93.5 parts by weight Coloring material: benzimidazolone pigment, Pigment Yellow 154 4 parts by weight Charge control agent: BONTRON E84 (manufactured by Orient Chemical Co.) 0 0.5 parts by weight Wax Viscole 660-P (manufactured by Sanyo Kasei) 2 parts by weight The above composition was mixed and stirred by a ball mill, melt-kneaded by an extruder heated to 140 ° C., cooled and solidified, and then coarsely crushed by a crusher. Further, it was pulverized with a jet mill. The obtained fine powder is classified with an air classifier for 5 to 20
μm toner was obtained. Next, the following titanium dioxide was externally added to the toner using a Henschel mixer. TiO ₂ : Primary particle diameter 0.01 μm Secondary particle diameter 0.3 μm Surface treatment agent Octanetrimethoxysilane as silane coupling agent Electric resistance 10 ⁸ Ω · cm Crystalline anatase addition amount 1 wt% As toner of other colors A toner in which only the yellow toner and the pigment were changed was manufactured as a prototype. [Toner 13] Magenta Toner Pigment: Quinacridone Pigment Pigment Red 122 [Toner 14] Cyan Toner Pigment: Copper Phthalocyanine Pigment Pigment Blue 15

[0081]

[Table 9]

[0082]

[Table 10]

[Multicolor Image Forming Apparatus (FIG. 1)] The one shown in FIG. 1 described in the first aspect was used. [ Example 31 ] 100,000 continuous full-color printings were performed using the toners 11 to 14 and the multicolor image forming apparatus, and evaluated under the following conditions. i) Printer process speed: 10 mm / s ii) Number of printed sheets: 100,000 sheets iii) Fixing device (soft roller) -Silicone rubber thickness: 15 mm As the evaluation standard, as shown in Table 12, four grades of ◎, ○, △, × are used. And

[0084]

[Table 11]

Color development: Vivid color development was realized. -Good screen printability: No edge effect, and a uniform solid image can be formed.・ Environmental characteristics: Printing characteristics do not change and color tone does not change even if environmental conditions are changed between 25 ° C and 20 to 80% RH. -No toner scattering: No toner scattering due to poor charging and no toner contamination inside the device. -No fogging: No fogging occurs during development due to poor charging. -Image gloss: The smoothness of the fixed image is excellent and a good glossiness is realized. -Offset resistance: No offset occurs even after printing 100,000 sheets. -Fluidity: The toner has excellent fluidity and toner can be replenished smoothly. Excellent development and transfer characteristics. -Continuous printing characteristics: No change in printing characteristics after 100,000 sheets.

As a result, all the above characteristics were satisfied. [ Example 32 ] In the toner 13 (magenta toner), the pigment was changed from a quinacridone pigment to a naphthol pigment (Pigment Red 1).
As a result of continuous printing of 100,000 sheets in the same manner as in Example 1 except that the change to 84) was performed, good characteristics could be realized as in Example 31 . Example 33 In the toner 13 (magenta toner), the pigment was changed from a quinacridone pigment to an azo lake pigment (Pigment Red 5).
As a result of continuously printing 100,000 sheets in the same manner as in Example 31 except that the ratio was changed to 7: 1), good characteristics were realized as in Example 31 . [ Examples 14 to 42 , Comparative Examples 21 to 31] Further, Examples and Comparative Examples are summarized in the attached table.

[0087]

[Table 12]

[0088]

[Table 13]

[0089]

[Table 14]

[0090]

[Table 15]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[Brief description of drawings]

FIG. 1 illustrates a multicolor image forming apparatus.

FIG. 2 shows a semi-soft roll fixing machine.

FIG. 3 shows a soft roll fixing device.

[Explanation of symbols]

21 ... Heater 22 ... Heat roller 23 ... Pressure roller 24 ... Spring 25 ... felt 26 ... Silicone rubber 27 ... Fluororesin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G03G 15/01 G03G 9/08 346 15/20 103 361 (72) Inventor Norio Saruwatari 1015 Kamitadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Incorporated (72) Inventor Ken Ogino 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited (56) Reference JP-A-6-95429 (JP, A) JP-A-7-152206 (JP, A) ) JP-A-7-49587 (JP, A) JP-A-4-81772 (JP, A) JP-A-2-293867 (JP, A) JP-A-7-146589 (JP, A) JP-A-2- 5073 (JP, A) JP-A-5-341577 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08-9/097 G03G 15/00

Claims (12)

(57) [Claims] 1. A roller base using three colors of a yellow toner, a magenta toner, and a cyan toner composed of a binder resin, a charge control agent, a colorant, and an external additive, or a color toner containing the three color toner and a black toner. Thickness 2-3 on material surface
An image forming method by multicolor electrophotography, which comprises a step of heat fixing using a semi-soft roller having 0 mm of silicone rubber coated and a surface thereof coated with a fluororesin,
The binder resin of the color toner is composed of an alcohol component and an acid component, the alcohol component is a dihydric alcohol, and the acid component is a polyvalent carboxylic acid and the following general formula: (In the formula, R ¹ , R ² and R ³ are saturated or unsaturated hydrocarbon groups having 6 to 24 carbon atoms) , and the divalent carboxylic acid and its anhydride
A yellow resin used as a colorant for the yellow toner is a benzimidazolone pigment, and the yellow toner has an average particle diameter of 1 μm or less and is dispersed in the yellow toner. And a toner using titanium dioxide powder surface-treated with a silane coupling agent as an external additive, wherein the magenta toner has a magenta pigment used as a colorant dispersed in the magenta toner with an average particle size of 1 μm or less, and A toner using titanium dioxide powder surface-treated with a silane coupling agent as an external additive, wherein the cyan toner has a cyan pigment used as a coloring material dispersed in the cyan toner with an average particle size of 1 μm or less, and A toner using titanium dioxide powder surface-treated with a silane coupling agent as an additive. An image forming method by multicolor electrophotography, wherein the chloroform-insoluble portion of the reester resin is 20% by weight or less of the polyester resin, and the charge control agent is a calixarene compound. 2. The image forming method according to claim 1, wherein the polyvalent carboxylic acid contains terephthalic acid or an anhydride thereof. 3. The polyvalent carboxylic acid is trimellitic acid,
Alternatively, the image forming method according to claim 1, further comprising an anhydride thereof. 4. The image forming method according to claim 1, wherein the dihydric alcohol is represented by the following general formula. [Chemical 2] (In the formula, R ⁴ is an alkylene group having 2 to ⁴ carbon atoms, and the average value of the sum of the carbon numbers is 2 to 16) 5. The binder resin contains a mixture of the polyester resin and a linear polyester resin.
The image forming method according to any one of 1. 6. The image forming method according to claim 1, wherein the magenta pigment is a naphthol-based pigment. 7. The image forming method according to claim 1, wherein the cyan pigment is a copper phthalocyanine pigment. 8. The average particle diameter of the primary particles of the titanium dioxide powder is 0.001 to 0.1 μm, and the average particle diameter of the titanium dioxide powder in the state of being adhered to the toner surface is 1. The image forming method according to claim 1, which has a thickness of 0 μm or less. 9. The titanium dioxide powder has an electric resistance of 1 ×.
The image forming method according to claim 8, wherein the image forming method is 10 ⁶ to 1 × 10 ¹² Ω · cm. 10. The image forming method according to claim 9, wherein the crystal form of the titanium dioxide powder is anatase. 11. The image forming method according to claim 6, wherein the silane coupling agent used as a coating agent for the titanium dioxide powder is n-butyltrimethoxysilane. 12. The image forming method according to claim 6, wherein the amount of the titanium dioxide powder added is 0.1 to 2.0 wt% of the toner.