JP3006054B2 - Dry color toner for full color - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a full-color dry color toner used in the field of electrophotography.

[Prior Art] US Patent No. 2,297,691 and Japanese Patent Publication No. Sho 4 as a conventional electrophotographic method
Various methods are described in, for example, Japanese Patent Publication No. 2-323910 and Japanese Patent Publication No. 43-24748.Generally, a photoconductive substance is used, and an electric latent image is formed on a photoreceptor by various means.
Next, the latent image is developed with toner, and a powder image is transferred to paper or the like as necessary, and then fixed by heating, pressing, or solvent vapor.

In recent years, an electrostatic latent image of an original is formed by exposing with spectral light, and is developed with a color toner of each color to obtain a colored copy image, or a full-color copy image is superimposed on each color copy image. Color copying methods for obtaining images have also been put to practical use.

As the toner, a binder resin such as a polyester resin in which various dyes and pigments are contained as a colorant, and a toner in which a charge control agent or the like is dispersed as needed is 1 to 30.
Particles finely pulverized to about μm are used, and such a toner is used by being mixed with a carrier substance such as glass beads, iron powder or fir.

[Problems to be Solved by the Invention] Conventionally used toners have the following problems.

1) Since fixing cannot be performed at a low temperature, energy consumption is large and is not suitable for high-speed fixing.

2) A high-temperature offset phenomenon is likely to occur at the time of fixing with a hot roll, and the load on a fixing device is large.

3) Adhesion or migration to a soft vinyl chloride sheet is observed, and image contamination or omission is likely to occur.

4) Transparency and gloss after fixing are poor and cannot be used for full color toner applications.

5) Long-term use is not possible due to low mechanical durability.

In order to solve these problems, many studies have been made on the material and prescription of the toner. In general, polyester resins are considered to be more advantageous than styrene resins in terms of vinyl chloride adhesion and low-temperature fixability. It is also used as a resin for full-color toner because of its excellent transparency. However, some problems still remain, and there is no general satisfaction yet. Therefore, quick improvement has been desired.

[Means for Solving the Problems] The present invention has been made based on such circumstances.
It is an object of the present invention to provide a high-performance full-color dry color toner that has solved the above-mentioned problems.

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that the characteristics of the low softening point and the softening point are different.
By using a combination of different types of polyester resin, the polyester resin having a low softening point mainly contributes to low-temperature fixability, transparency and glossiness, and the polyester resin having a softening point,
As a result of mainly contributing to prevention of high-temperature offset and improvement of mechanical durability, the present inventors have found that the above object can be sufficiently satisfied, and arrived at the present invention.

That is, the gist of the present invention is a colorant, a softening point of 80 to 130.
And a second polyester resin having a softening point of 170 ° C. or higher, wherein the second polyester resin is added to 100 parts by weight of the first polyester resin. 1 to 30
Part by weight of a dry color toner for full color.

<Operation> Hereinafter, the present invention will be described in detail.

The polyester resin used in the present invention is not limited at all, and any known polyester resin such as a linear resin and a three-dimensionally cross-linked non-linear resin can be used.

The polyester resin according to the present invention comprises a polyhydric alcohol and a polybasic acid. If necessary, at least one of the polyhydric alcohol and the polybasic acid contains a trifunctional or higher polyfunctional component. It is obtained by polymerizing the components.

In the above, examples of the dihydric alcohol used for the synthesis of the polyester resin include ethylene glycol, diethylene glycol, triethylene glycol,
Diols such as 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, and 1,6-hexanediol;
Examples include bisphenol A alkylene oxide adducts such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylene bisphenol A, and the like. Among these monomers, it is particularly preferable to use a bisphenol A alkylene oxide adduct as a main component monomer, and more preferably an adduct having an average alkylene oxide addition number of 2 to 7 per molecule.

Examples of the trihydric or higher polyhydric alcohol involved in the crosslinking of polyester include sorbitol, 1, 2, 3, 6
Hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol,
1,2,5-pentanetriol, glycerol, 2-
Methylpropanetriol, 2-methyl-1,2,4-
Butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and others.

On the other hand, as polyhydrochloric acid, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, flutaic acid, isoflutaic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid Examples include acids, anhydrides of these acids, lower alkyl esters, and other divalent organic acids.

Examples of the trivalent or higher polybasic acid involved in the crosslinking of the polyester include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4
-Cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3
-Dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane,
Examples thereof include 1,2,7,8-octanetetracarboxylic acid, anhydrides thereof, and others.

In the present invention, a first polyester resin having a softening point of 80 to 130 ° C. and a second polyester resin having a softening point of 170 ° C. or more are mixed and used. Of these, the first polyester resin having a low softening point has a low melt viscosity, which contributes to low-temperature fixability and transparency and glossiness, and the second polyester resin having a high softening point has a large elastic modulus, so that a high-temperature offset can be obtained. It is effective for prevention and improvement of mechanical durability.

Among them, as the second polyester resin having a softening point of 170 ° C. or more, for example, U Polymer Series U-82
00, U-8300, U-8400 (all manufactured by Unitika)
Commercial products such as can be used.

The mixing ratio of the first polyester resin and the second polyester resin varies depending on the required characteristics of the toner and the performance of the copying apparatus itself, but generally, the mixing ratio of the second polyester resin to 100 parts by weight of the first polyester resin is 100 parts by weight. The polyester resin is preferably adjusted in the range of 1 to 30 parts by weight. If the amount of the second polyester resin is smaller than this, high-temperature offset and durability deterioration become problems. If it is too large, problems arise in low-temperature fixability, transparency and glossiness.

Further, in the toner of the present invention, these two types of polyesters are mixed and used, but the content of both components in the toner is not limited at all. For example, at the end of the polymerization reaction of the first polyester resin, the second polyester resin is directly added to the reaction vessel, mixed and dissolved, and then taken out. And a method of melting and kneading can be appropriately adopted.

Furthermore, when the acid value of the polyester resin is generally high,
Since the charge stability at high temperature and high humidity tends to deteriorate, the acid value of the polyester resin of the present invention is
It is preferable to adjust the concentration to 10 KOH mg / g or less, more preferably 5 KOH mg / g.

Methods for adjusting the acid value to a low level include, for example, a method of synthesizing an acid monomer component using a lower alkyl ester obtained by transesterification, or adding a basic component such as an amino group-containing glycol to the composition. By doing so, a method of neutralizing the residual acid group may be mentioned, but it is needless to say that the present invention is not limited thereto, and any known method can be adopted.

The polyester resin in the present invention can be synthesized by a generally known method. Specifically, conditions such as a reaction temperature (170 ° C. to 250 ° C.) and a reaction pressure (5 mmHg to normal pressure) are determined according to the reactivity of the monomer, and the reaction is terminated when predetermined physical properties are obtained. I just need.

As the toner resin, in addition to the above-mentioned resin component according to the present invention, if necessary, the addition of another resin during the production of the toner may be considered. As this kind of resin,
For example, various known resins such as an epoxy resin, a styrene / aminoacryl copolymer resin, a styrene / aminoacryl copolymer resin, and a silicone resin can be used. Colorants that can be used in the present invention include carbon black, lamp black, and iron black. , Ultramarine, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, monoazo and disazo dyes Pigments may be used alone or in combination. These colorants are preferably 0.5 to 20 parts by weight, more preferably 2 to 10 parts by weight based on 100 parts by weight of the resin.
Used in parts by weight.

Further, a magnetic derivative can be contained in the toner for the purpose of improving the image on the developing mechanism or the image.
Examples of the magnetic powder include alloys and compounds containing ferromagnetic elements such as ferrite and magnetite. The magnetic material is contained in a resin in the form of a fine powder having an average particle diameter of 0.05 to 1 μm in an amount of 70% by weight or less. The amount can be dispersed and used.

In the present invention, other components such as a charge control agent may be included as necessary.

As the charge control agent, any known charge control agents can be used. For example, there are nigrosine dyes, quaternary ammonium salts, styrene / aminoacrylate copolymers, polyamine resins and the like for positive charging, and azo dyes containing metals such as chromium, cobalt and aluminum, and metals of alkyl salicylic acid for negative charging. Salts and the like are known. The amount used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the resin. The charge control agent may be used in the form of being mixed with the resin or attached to the surface of the toner particles.

In addition, auxiliary agents such as various plasticizers and release agents can be added to the toner for the purpose of adjusting heat retention, physical properties, and the like. For example, low molecular weight polyolefin for improving the offset property, colloidal silica for improving the fluidity, and the like can be mentioned. The addition amount is suitably 0.1 to 10 parts by weight based on 100 parts by weight of the resin.

The general method for producing the toner of the present invention is as follows.

A resin, a colorant, a charge control agent, and the like are uniformly dispersed with a Henschel mixer or the like.

The dispersion is melt-kneaded with a kneader, extruder, low mill or the like.

The kneaded material is roughly pulverized with a hammer mill, a cutter mill or the like, and then finely pulverized with a jet mill or an I-type mill.

The finely divided material is classified using a dispersion classifier, a zigzag classifier, or the like.

In some cases, silica or the like is dispersed in the classified material using a Henschel mixer or the like.

When the toner of the present invention is used as a two-component developer by mixing with a carrier, the carrier has a particle size of 30 to 200 μm.
Conventionally known materials such as iron powder, ferrite powder, and magnetite powder of about m can be used. Further, those obtained by coating these surfaces with a silicone resin, an acrylic resin, a fluororesin, or the like, or a mixture of these resins can also be suitably used. The mixing weight ratio of carrier and toner is 10
0: 1 to 10 is good.

The softening point of the resin in the present invention is JIS K7210 and K6
The measurement was performed using a flow tester described in 719. Specifically, as shown in FIG. 1, a flow tester (CFT
-500, manufactured by Shimadzu Corporation) while heating at a rate of 6 ° C./min. About 1 g of sample 3 while applying a load of 20 kg / cm ^{2 with} a plunger 1 having an area of 1 cm ² to obtain a hole diameter of 1 mm and a length of 1 mm. Extrude from 1mm die 4. In this manner, a plunger stroke temperature curve as shown in FIG. 2 is drawn, and when the height of the S-shaped curve is h, the temperature corresponding to h / 2 is the softening temperature.

On the other hand, the acid value of the polyester resin in the present invention is JI
It is measured according to the method described in S K0070.

[Examples] Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto. In the examples, “parts” indicates “parts by weight”.

Synthesis Example 1 (Production of polyester resin A having low softening point) Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (average molecular weight: about 355, the same applies hereinafter) 1070 g Fumaric acid 240 g Benzene-1, A substance of 40 g or more of 2,4-tricarboxylic acid was placed in a glass 2-liter four-necked flask, fitted with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube. The reaction was carried out while stirring at 200 ° C. normal pressure and 220 ° C. reduced pressure in the first half.

The resulting polyester resin had an acid value of 2.0 KOHmg / g and a softening point of 111 ° C.

Synthesis Example 2 (Production of polyester resin B having low softening point) Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 540 g Polyoxyethylene (2.2) -2,2-bis (4-hydroxy (Phenyl) propane (average molecular weight: about 325) 490 g Terephthalic acid The reaction was carried out in the same manner as in Synthesis Example 1 except for using a substance of 330 g or more to obtain a polyester resin.

The acid value of the obtained polyester resin was 3.3 KOHmg / g, and the softening point was 98 ° C.

Synthesis Example 3 (Production of polyester resin C having a high softening point) Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 1070 g Fumaric acid 150 g Benzene-1,2,4-tricarboxylic anhydride 150 g A polyester resin was obtained by performing a reaction in the same manner as in Synthesis Example 1 except that the above substances were used.

The acid value of the obtained polyester resin was 0.8 KOHmg / g, and the softening point was 182 ° C.

Examples and Comparative Examples Table 1 shows a list of toner compositions of Examples 1, 2 and Comparative Example 1.

 The method for producing the toner was as follows.

Each of the toner materials was melted in a kneader, coarsely ground using a hammer mill, and then finely ground by a fine mill using an air jet method. The resulting fine powder was classified to a particle size of 5
To 20 μm was selected to obtain a toner. The volume average particle size measured by the Coulter counter was 10 ± 0 in all cases.
It was in the range of 5 μm.

A developer is prepared by mixing the toner and the carrier, and a ferrite powder having an average particle size of about 70 μm coated with a silicone resin is used as the carrier.
Each of the toner concentrations was 5 wt%, and the mixture was mixed for a predetermined time in a V blender to obtain a developer.

In addition, when performing image output with the above developer,
A commercially available copying machine was used, and an organic photoconductor was used, and selenium was used as a photoconductor in a negatively chargeable developer.

The following tests were performed using these toners and developers to evaluate the toners.

(Triboelectric Charge) The triboelectric charge of the developer was measured by a blow-off method.

(Minimum fixing temperature and anti-offset temperature) Unfixed with a fixed amount of toner developed using a fixing unit with a temperature-changed hot roll fixing device (upper roll: Teflon, lower roll: silicone) of a commercial copying machine Through the paper. The same is repeated while changing the heat roll temperature, and the lowest roll temperature at which the toner image is not peeled off by rubbing with a finger is set as the minimum fixing temperature. The highest roll temperature at which no occurrence of the high-temperature offset phenomenon is visually observed is defined as the anti-offset temperature.

(Vinyl chloride resistance) After inserting soft vinyl chloride in the form of a white sheet into the toner placed in the container, visually check the toner contamination on the vinyl chloride sheet when it is kept at 50 ° C for 24 hours. Observe. Those that do not contaminate at all are evaluated as ○, and those that contaminate are evaluated as X.

(Transparency of OHP) Reproducing a clear color tone even when transmitted through an overhead projector (OHP) is an essential performance for full-color toner. The OHP transmissivity was determined by visually permeating the OHP sheet on which the toner image was fixed with OHP and visually checking.

○: good color reproduction of transmitted image, ×: unclear color
And

(Continuous Real-Photograph Test) Using the prepared developer, a continuous real-photograph test of 100,000 sheets was performed with the copying machine as described above. In the evaluation, durability was determined by comprehensively observing changes in image quality centered on changes in image density and fog.

 Table 2 summarizes the evaluation results of the above tests.

As is clear from the above, the toner of the present invention has excellent performance.

[Effects of the Invention] The effects obtained by the present invention are as follows.

By using the dry color toner for full color of the present invention, (1) since fixing can be performed at a relatively low temperature, sufficient fixing strength can be obtained with low energy consumption.

(2) Since high-temperature offset development hardly occurs at the time of hot roll fixing, a clear toner-fixed image without stain can be obtained under all fixing conditions.

(3) Since toner does not adhere to or migrate to the soft vinyl chloride sheet, toner images are not lost or contaminated.

(4) Since it has good OHP transparency, it is useful as a full-color toner.

(5) Since the mechanical durability is high, the same image quality as in the initial stage can be maintained even when used for a long time or continuously.

As described above, according to the present invention, a toner having excellent effects can be obtained by an easy method, and thus the present invention is extremely useful industrially.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a central portion of the flow tester, and FIG. 2 is a plunger stroke (displacement) -temperature curve of the flow tester. 1 ... plunger 2 ... cylinder 3 ... sample 4 ... die 5 ... die presser

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirofumi Oda 370 Yenzo, Chigasaki-shi, Kanagawa Pref. Inside the Chigasaki Works of Mitsubishi Chemical Corporation (56) References JP-A-64-15755 (JP, A) JP-A-63- 225244 (JP, A) JP-A-63-225245 (JP, A) JP-A-63-225246 (JP, A) JP-A-2-82267 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (1)

(57) [Claims] 1. A full-color dry color toner containing a colorant, a first polyester resin having a softening point of 80 to 130 ° C., and a second polyester resin having a softening point of 170 ° C. or higher, wherein A dry color toner for full color, comprising 1 to 30 parts by weight of a polyester resin based on 100 parts by weight of the first polyester resin.