JP2000029242A - Electrophotographic full-color toner and electrophotographic image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a full-color toner for electrostatic charge development having good luster, transparency and blocking resistance, not causing offsetting phenomenon and sheet winding phenomenon and also having good fixability. SOLUTION: In an electrophotographic full-color toner contg. at least a binder resin, a specified additive, a colorant and an electrostatic charge controlling agent, a polyester resin having 90-120 deg.C softening point is contained as the binder resin and a fatty acid amide or silicone oil is contained as the additive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a full-color toner for electrophotography and an electrophotographic image forming method. Specifically, at least a specific binder resin, a specific additive,
The present invention relates to a full-color electrophotographic toner containing a colorant and a charge control agent. The toner of the present invention has good gloss, transparency and blocking properties, and when the toner is fixed by a heating roller fixing method that does not supply an anti-offset liquid such as silicone oil, no offset phenomenon or sheet wrapping phenomenon occurs. It has a wide fixing temperature range, good fixability, high image density, little image fouling such as fog, and is used as a full-color toner for developing electrostatic images in electrophotographic copying machines and printers.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat. No. 2,297,691.
Specification, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 4
As disclosed in JP-A-3-24748 and the like, an electrostatic latent image is generally formed on a photoconductor containing a photoconductive material by various means, and then the latent image is developed as a powder image with toner. After transferring to paper etc. as necessary, heating,
The fixing is performed by pressurization or solvent vapor. As the heat fixing method, there are an oven fixing method, a flash fixing method, a pressure fixing method, a heating roller fixing method and the like, and a heating roller fixing method is generally used in an electrophotographic copying machine and the like.

This method has extremely good thermal efficiency when an image is fused on a sheet to be fixed, such as paper or a sheet for an overhead projector, and can fix the image quickly.
Particularly, it is extremely effective as a fixing method at the time of high-speed copying. However, in this method, a part of the toner image adheres to the fixing roller because the toner image and the surface of the fixing roller come into pressure contact with each other in a heated and melted state. A so-called offset phenomenon that causes stains on the sheet occurs, and a sheet winding phenomenon occurs.

Conventionally, as a method for preventing the offset phenomenon and the sheet wrapping phenomenon, a roller surface is formed of a material such as silicone rubber or a fluororesin which is excellent in releasability from a toner, and a silicone oil is formed on the surface. Such as supplying a liquid having good releasability, and coating the roller surface with the thin film. However, this method is extremely effective in preventing the offset phenomenon and the sheet wrapping phenomenon, but requires a liquid supply device, so that the fixing device becomes complicated, and the sheet is fed by silicone oil or the like when performing double-sided printing. However, there are problems such as that the sheet does not go smoothly and that the sheet for the overhead projector becomes sticky.

Therefore, as a method for preventing the offset phenomenon from occurring without supplying an anti-offset liquid such as silicone oil to the surface of the fixing roller, for example, the roller surface is made of a material having excellent releasability from a toner such as a fluororesin. JP-A-49-65231 and JP-A-58-162 describe a method of forming a toner and containing an olefin wax such as low molecular weight polypropylene and low molecular weight polyethylene in the toner.
50, JP-A-50-27546, JP-A-55-1539
Japanese Patent Application Laid-Open No. 50-134652 proposes a method of using a resin having a wide molecular weight distribution as a binder. However, these methods are insufficient in the effect of suppressing the offset phenomenon and the sheet wrapping phenomenon, and do not exhibit satisfactory performance in terms of gloss and transparency at the time of color mixing when applied to a full-color toner.

As is well known, a toner includes a binder resin,
A colorant, a charge controlling agent, and other components, if necessary, are mixed and kneaded, and then finely pulverized to about 1 to 30 μm. As the binder resin, a polystyrene resin, a polyester resin, or the like is mainly used. It is used for The toner is used as a one-component developer or as a two-component developer by being mixed with iron powder, ferrite powder, magnetite powder or the like having a powder diameter of about 10 to 200 μm called a carrier. As a method for producing toner, first, a binder,
Colorant, charge control agent, and if necessary, other components are uniformly dispersed and mixed in a mixer, and then the mixture is melt-kneaded in a closed kneader, or a single- or twin-screw extruder,
After cooling, it is coarsely crushed by a crusher, hammer mill, etc., finely crushed by a jet mill, a high-speed rotor rotary mill, etc., and is classified by an air classifier (eg, elbow jet of inertial classification, microplex of centrifugal classification, DS separator). etc)
A method of classifying by means such as is common. As a mixing device for the toner and the carrier, a double mixer, a V-type mixer, a drum type mixer, a super mixer, a Henschel mixer, a Nauta mixer and the like are generally used.

[0007]

As described above, the conventional toner cannot sufficiently suppress the offset phenomenon and the sheet wrapping phenomenon, and particularly has a problem in performance such as gloss when applied to a full-color toner. . An object of the present invention is to provide a fixing device which does not generate an offset phenomenon or a sheet wrapping phenomenon when a toner is fixed by a heating roller fixing method which does not supply an anti-offset liquid such as silicone oil and has good gloss, transparency and blocking properties. An object of the present invention is to provide a full-color toner for developing an electrostatic image having a wide temperature range and good fixability. Another object of the present invention is to provide a high image density,
An object of the present invention is to provide a full-color toner for developing an electrostatic charge image with less stain such as fog. Further, another object of the present invention is to provide
An object of the present invention is to provide a full-color toner having good gloss and transparency when mixed colors, and having good color reproducibility when transferred to paper or a sheet for an overhead projector.

[0008]

The present inventors have conducted intensive studies in view of the above circumstances, and have found that a toner containing a specific binder resin, a specific additive, a colorant, and a charge control agent is a conventional toner. The inventors have found that the above problems have been solved, and that they have excellent characteristics, and have completed the present invention. That is, the gist of the present invention is to provide a full-color electrophotographic toner containing at least a binder resin, an additive, a colorant, and a charge control agent, wherein the binder resin has a softening point of 9%.
A full-color toner for electrophotography, wherein the additive is a polyester resin at 0 to 120 ° C., and the additives are a fatty acid amide and a silicone oil. Hereinafter, the present invention will be described in detail.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The color toner of the present invention contains at least a hinder resin, an additive, a colorant and a charge control agent in the toner. As the binder resin, a polyester resin having a softening point of 90 to 120 ° C is used. This polyester resin is obtained by subjecting a carboxylic acid and an alcohol to polycondensation in the presence of a catalyst.
Examples of the acid component include aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, trimellitic acid, pyromellitic acid, and benzophenonetetracarboxylic acid; and p- (2-hydroxyethoxy) benzoic acid. Aromatic oxycarboxylic acids; aliphatic polycarboxylic acids such as succinic acid, fumaric acid, adipic acid, azelaic acid, sebacic acid, decamethylenedicarboxylic acid; 1,4-cyclohexanedicarboxylic acid, 1,3-
Examples thereof include aliphatic polycarboxylic acids such as cyclohexanedicarboxylic acid, hexahydrophthalic acid, and tetrahydrophthalic acid.

The alcohol component includes ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylol. Aliphatic polyols such as ethane, trimethylolpropane and pentaerythritol; aliphatic polyols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; and ethylene oxide or propylene oxide adducts of bisphenol A. .

As a specific example of the polyester resin, for example, 2,2-bis (4-hydroxypropoxy)
Examples include polycondensates of phenylpropane, 2,2-bis (4-hydroxyethoxy) phenylpropane, terephthalic acid, and trimellitic acid. The polyester resin used as a binder needs to have a softening point of 90 to 120 ° C. When the softening point is 90 ° C. or lower, the fixing property and the blocking property deteriorate. Conversely, if the softening point exceeds 120 ° C., the gloss and the transparency deteriorate.

Incidentally, in the color toner of the present invention,
The above polyester resin is used alone as a usual binder resin, but if desired, other resins can be used in combination. When another resin is used in combination, the amount of the resin must be limited to a range that does not impair the properties of the polyester resin. Usually, the above-mentioned polyester resin accounts for 70% by weight or more, preferably 80% by weight or more of the whole binder resin.

As additives, fatty acid amides and silicone oils are used. In the present invention, good characteristics are obtained only when these two types of additives are used together. Examples of the fatty acid amide include amide 6S (bisamide stearate, melting point 135 to 145 ° C, manufactured by Kawaken Fine Chemical Co., Ltd.) and EB-FF (ethylene bisstearic acid amide, melting point 141.5 to 146.5).
C., Kao Corporation), WX-1 (hydroxystearate bisamide, melting point 142-148 ° C., manufactured by Kawaken Fine Chemical Co., Ltd.), VLA-1 (higher fatty acid bisamide, melting point 126-130 ° C., Kawaken Fine Chemical) (Manufactured by Kao Corporation) and fatty acid amide S (stearic amide, melting point: 100 to 105 ° C., manufactured by Kao Corporation). In the present invention, a fatty acid bisamide is preferred.

Examples of the silicone oil include various silicone oils such as straight silicone such as dimethyl silicone oil, methylphenyl silicone oil and methyl hydrogen silicone oil, polyether-modified silicone oil, epoxy-modified silicone oil and methacryl-modified silicone oil. . In the present invention, straight silicone is preferred, and dimethyl silicone oil is particularly preferred.

The viscosity of the silicone oil is 1 to 10,000
Preferably, it is centistokes. Furthermore, 10-1
Particularly preferred is 000 centistokes. Silicone oil viscosity less than 1 centistoke or 1
If it exceeds 0000 centistokes, the fixability deteriorates. The amount used is based on 100 parts by weight of the binder resin.
It is preferable to contain 0.5 to 5 parts by weight of fatty acid amide and 0.05 to 1 part by weight of silicone oil. If the amount of the fatty acid amide is less than 0.5 part by weight or the amount of the silicone oil is less than 0.05 part by weight, the fixability deteriorates. When the amount of the fatty acid amide exceeds 5 parts by weight, gloss, transparency, and blocking properties deteriorate. When the amount of the silicone oil exceeds 1 part by weight, the concentration decreases.

If desired, besides fatty acid amide and silicone oil, paraffin wax, higher fatty acid,
A small amount of fatty acid amide, metal soap or the like may be added. Colorants include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl. Any known dyes and pigments such as methane dyes, monoazo dyes, disazo dyes and condensed azo dyes can be used alone or in combination. In the case of full-color toner, yellow uses benzidine yellow, monoazo dyes and pigments, condensed azo dyes and pigments, magenta uses quinacridone, rhodamine dyes and pigments, monoazo dyes and pigments, cyan uses phthalocyanine blue, and black uses carbon black. Is preferred. The colorant is used usually in an amount of 3 to 20 parts by weight based on 100 parts by weight of the binder.

As the charge controlling agent, various known positively charged or negatively charged agents can be used. Preferably, JP-A-53-127726 and JP-A-62-145 are preferred.
No. 255, a metal salt or a metal complex of salicylic acid or alkyl salicylic acid described in US Pat. For example, a salt or a complex of 3,5-di-tert-butylsalicylic acid with a metal, particularly a metal salt or a metal complex of 3,5-di-tert-butylsalicylic acid with chromium, aluminum, or zinc is preferably used. In addition, Japanese Patent Application Laid-Open No. 2-2219
Those using the compound represented by the formula (1) described in JP-A-67-67 are also preferable.

[0018]

Embedded image

[Wherein, R ¹ and R ⁴ represent a hydrogen atom, an alkyl group, or a substituted or unsubstituted aromatic ring (including a condensed ring), and R ² and R ³ represent a substituted or unsubstituted aromatic ring ( And M represents a metal, X represents a cation, and m and n represent natural numbers.]

In the formula (1), when R ¹ and R ⁴ are alkyl groups, R ¹ and R ⁴ are a methyl group, an ethyl group,
n-butyl group, iso-amyl group, n-dodecyl group, n
-Represents an octadecyl group, a cyclohexyl group or the like. R ¹ ,
When R ² , R ³ and R ⁴ are aromatic rings, these represent a benzene ring or a naphthalene ring. Examples of the substituent of the aromatic ring include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aralkyl group, a nitro group, and a cyan group. Examples of M include metals such as Cr, Fe, Co, Ti, and B. Various inorganic cations and organic cations can be used as the cation. Examples of the inorganic cation include a hydrogen ion and a metal ion. Examples of the metal ion include Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , and C 2.
Monovalent or divalent ones such as a ²⁺ and Zn ²⁺ are mentioned. Examples of the organic cation include an ammonium ion, an iminium ion, and a phosphonium ion.

As the compound represented by the formula (1), for example, the compound No. 3 whose structural formula is described in the items 3 and 4 of JP-A-2-22167 is disclosed. 1 to 9 are used. One or more kinds of charge control agents may be used in combination, and the amount of use may be determined depending on the desired charge amount of the toner. Usually 0.1 to 100 parts by weight of binder
It is preferable to use 10 parts by weight.

The color toner according to the present invention consists essentially of the binder resin, additives, colorant and charge control agent described above, but may further contain other components if desired. Other components include fine powder silica,
Fluidity improvers such as alumina and titania, magnetite,
Ferrite, cerium oxide, strontium titanate,
An inorganic fine powder such as conductive titania, a resistance adjuster such as a styrene resin or an acrylic resin, a lubricant, or the like is used as an internal additive or an external additive. These additives are usually used in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the binder resin.

The production of the color toner according to the present invention from the above-mentioned components can be carried out according to a conventional method.
Usually, first, a binder resin, an additive, a colorant, a charge controlling agent, and other components to be added as necessary are uniformly dispersed and mixed by a mixer, and then the mixture is sealed in a closed kneader, or a uniaxial or biaxial. Melt kneading with an extruder, etc., and after cooling, coarsely crushing with a crusher, hammer mill, etc., finely pulverizing with a jet mill, high-speed rotor rotary mill, etc., and a wind classifier (for example, an inertial classification type elbow jet, centrifugal Classification using a force classification microplex, a DS separator, or the like) is employed. When the color toner according to the present invention is used as a two-component developer, known carriers such as iron powder, magnetite powder, and ferrite powder can be used as the carrier.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following Examples and Comparative Examples, the softening point, gloss, transparency, blocking property, density and fog were measured as follows.

Softening point: In a flow tester (CFT-500, manufactured by Shimadzu Corporation), 1 g of a sample was sprayed with a 1 mm nozzle.
The measurement is performed under the conditions of 10 mm, a load of 30 kg, a preheating time of 50 ° C. for 5 minutes, and a heating rate of 3 ° C./min, and the temperature at the midpoint of the distance from the start to the end of the flow is defined as the softening temperature.

Gloss: An image fixed on a commercially available plain paper at 160 ° C. was evaluated. ○ Good for practical use, with appropriate gloss. △ Practically usable, slightly less glossy. × Not practical, no gloss.

Transparency: An image fixed on a projector sheet at 160 ° C. with a commercially available overhead was projected by an overhead projector and evaluated. ○ Good in practical use, color reproducibility is good and clear. △ Usable for practical use, color reproducibility is slightly inferior. × Not practical, black and cloudy.

Fixability: Offset phenomenon and paper wrapping phenomenon were examined by changing fixing temperature using commercially available plain paper. The fixing property was evaluated based on a fixing temperature range at which the offset phenomenon did not occur and the paper did not wind. ○ Good in practical use, wide fixing temperature range. △ Usable for practical use, fixing temperature range is slightly narrow. × Not practical, fixing temperature range is narrow.

Blocking property: 10 g of toner was placed in a cylinder having an inner diameter of 28 mm, a load of 3.3 g / cm ² was applied to the toner from above, and the blocking property was evaluated after being left in an environment of 50 ° C. for 5 hours. . ○ Good for practical use △ Can be used for practical use × Cannot be used for practical use

Density, fog; 16 images on commercial plain paper
The image was fixed at 0 ° C., and the density was evaluated by measuring the solid image density with a Macbeth densitometer. Fog was evaluated for toner fog on a white background image. ○ Practically good, has sufficient image density, and less image fouling such as fog. Δ Practically usable, image density is slightly insufficient or image stains such as fog are slightly large. × Unsuitable for practical use, image density is insufficient or there are many image stains such as fog.

Examples 1 to 7 and Comparative Examples 1 to 4 Production of Toner Polyester resins (2,2-bis (4-hydroxypropoxy) phenylpropane, 2,2-bis (4-hydroxyethoxy) phenylpropane and terephthalic Acid and trimellitic acid ester) 100 parts by weight Bisamide stearate dimethyl silicone oil Charge control agent 2 parts by weight Magenta pigment (color index; Pigment Red 122) 6 parts by weight After classification, a magenta toner having a volume average particle diameter of 9 μm was obtained.

Image formation and fixing: An unfixed image was formed using an electrophotographic copying machine using an organic photoconductor as a photosensitive member. The amount of toner attached was 0.5 mg / cm ² . The unfixed image was transferred and fixed to a commercially available plain paper and an overhead projector sheet. The fixing was performed using a heating roller fixing machine having a diameter of 20 mm made of silicone rubber and having a nip width of 4 mm and a fixing speed of 60 mm / sec. At the time of fixing, no offset preventing liquid such as silicone oil was supplied to the roller. The results are shown in Table 1.

[0033]

[Table 1]

[0034]

According to the present invention, when the toner is fixed by a heating roller fixing method which does not supply an anti-offset liquid such as silicone oil and has good gloss, transparency and blocking properties, an offset phenomenon and sheet wrapping are caused. A full-color toner for electrophotography which does not cause any phenomena, has a wide fixing temperature range, has good fixing properties, has a high image density, and has little image stains such as fog.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G03G 15/08 507 G03G 9/08 361 15/20 102 365 371 15/08 507L (72) Inventor Shinichi Saiki Niigata 1 at Fukudacho, Joetsu-shi Naoetsu Office, Mitsubishi Chemical Corporation (72) Inventor Takuya Nishikori 1 at Fukudacho, Joetsu-shi, Niigata Inside of Naoetsu Office, Mitsubishi Chemical Corporation F-term (reference) DA06 EA03 EA07 EA10 FB02 2H030 AD01 2H033 BA58 BB01 2H077 AE06 EA03

Claims (7)

[Claims] 1. An electrophotographic color toner containing at least a binder resin, an additive, a colorant, and a charge control agent, wherein the binder resin is a polyester resin having a softening point of 90 to 120 ° C., and the additive is A full-color toner for electrophotography, comprising a fatty acid amide and a silicone oil. 2. 0.5 to 5 parts by weight of a fatty acid amide and 0.05 to 1 part by weight based on 100 parts by weight of the binder resin.
2. The full-color toner for electrophotography according to claim 1, comprising a silicone oil in parts by weight. 3. The silicone oil has a viscosity of 1-10.
3. The full-color toner for electrophotography according to claim 1, wherein the toner is 000 centistokes. 4. The full-color toner for electrophotography according to claim 1, wherein the silicone oil is dimethyl silicone oil. 5. The charge control agent according to claim 1, wherein the charge control agent is a metal complex of salicylic acid or alkyl salicylic acid or a salt of salicylic acid or alkyl salicylic acid. 2. The full-color toner for electrophotography according to 1. 6. The full-color toner for electrophotography according to claim 1, wherein the charge control agent is a compound represented by the following general formula (1). Embedded image [Wherein, R ¹ and R ⁴ represent a hydrogen atom, an alkyl group, or a substituted or unsubstituted aromatic ring (including a condensed ring);
² and R ³ are substituted or unsubstituted aromatic rings (including condensed rings)
M represents a metal, X represents a cation, and m
And n represent natural numbers) 7. An electrostatic latent image is developed with toner.
An electrophotographic image forming method for fixing the toner image to the surface of the sheet to be fixed using a heating roller, wherein the full-color toner for electrophotography according to claim 1 is used as the toner, and the heating roller is used. An electrophotographic image forming method, wherein the toner is fixed on the sheet to be fixed without supplying an offset preventing liquid thereto.