JPH01309072A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain a toner always usable whatever environment it encounters, and always to obtain superior images in accordance with any environmental change by adding a fine silica powder as an external additive. CONSTITUTION:The toner contains the metal compound of a salicylic acid derivative substituted by a carboxyl or sulfo group is used as an electric charge controller. The fine silica powder is added as an essential external additive in order to enhance lubricity, thus permitting said metal compound of the salicylic acid derivative to have an effect of compensating the variance of triboelectrification amount of the silica powder due to change of the environment conditions, and consequently, the variance of triboelectrification amount of the toner to be extremely reduced by adding the fine silica powder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a new toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc.

[Prior Art] Conventionally, as an electrophotographic method, U.S. Patent No. 2.297°69
1 o'clock, Special Publication No. 42-23910, and Special Publication No. 43
Various methods are described in Japanese Patent No. 24748, etc., but in short, these methods provide static charges such as - on a photoconductive insulating layer and irradiate the insulating layer with a light image to generate static electricity. '', a ttm image is formed, and then the Wi image is developed +1j visualized with fine powder called toner in the art,
After transferring the powder image to paper etc. as necessary, heat, pressurize,
Alternatively, fixing is carried out using solvent vapor or the like.

The developing methods applied to these electrophotographic methods include:
Broadly speaking, there are dry development methods and wet development methods. The former is further divided into a method using a two-component developer and a method using a -component developer. Those belonging to the two-component developer category include a magnetic brush method using an iron powder carrier, a cascade method using a bead carrier, a fur brush method using fur, etc., depending on the type of carrier for conveying the toner.

In addition, those belonging to the -component type development method include a powder cloud method in which toner particles are sprayed, and a contact development method (contact development, or toner development method in which toner particles are brought into direct contact with an electrostatic Ws41t surface for development). (also called development),
The toner particles are not brought into direct contact with the static '-rLffi image surface,
There are the jumping development method, in which toner particles are charged and flown towards the latent image surface by the electric field of the electrostatic latent image, and the magnetry method, in which magnetic conductive toner is brought into contact with the electrostatic latent image surface and developed. .

Conventionally, toners used in these development methods are fine powders in which dyes and pigments are dispersed in natural or synthetic resins. Finely pulverized particles of about 1 to 301 L are used as toner. As the magnetic toner, one containing magnetic particles such as magnetite is used. In the case of a system using a so-called two-component developer, the toner is usually mixed with carrier particles such as glass beads and iron powder.

Further, the toner is made to have a positive or negative charge depending on the polarity of the electrostatic latent image to be developed.

In order to make the toner hold an electric charge, it is also possible to use the triboelectricity of the resin that is a component of the toner, but in this method, the toner's chargeability is small, so the image obtained by development is easily capricious and has poor performance. ! It will be T II. Therefore, in order to impart desired triboelectric charging properties to toners, dyes, pigments, and even charge control agents that impart charging properties are added to the toners.

Charge control agents known in the art today include nigrosine dyes, azine dyes, metal complexes of monoazo dyes, metal complexes of salicylic acid, metal complexes of naphthoic acid,
Examples include metal complex salts of dicarboxylic acids and copper phthalocyanine pigments.

Among these, metal complexes of salicylic acid have a high charge imparting ability through triboelectrification and are light-colored, so they are negatively charged charge control agents that can be widely used in color toners and magnetic toners. However, conventionally known metal complex salts of salicylic acid derivatives (for example, JP-A-62-145255
, Japanese Patent Publication No. 55-42752), the environmental dependence of triboelectrostatic stitching is large, and therefore, the image density fluctuations caused by the environment occur in copied images obtained with toners using conventionally known metal complex salts of salicylic acid derivatives as charge control agents. Fine silica powder is often externally added to toner, especially for the purpose of imparting fluidity, but this phenomenon is particularly noticeable with toners to which fine silica powder is externally added and toners using polyester as the binder resin. .

Therefore, there is a strong demand in this technical field for the development of a charge control agent that reduces the environmental dependence of toner triboelectric stitching.

[Problems to be Solved by the Invention] An object of the present invention is to provide a new technique for toner charge control that solves the above problems.

An object of the present invention is to provide a vivid chromatic developer.

A further object of the present invention is to provide a toner for developing electrostatic images in which environmental fluctuations in triboelectrostatic sewing are significantly suppressed when fine silica powder is externally added.

Another object of the present invention is to provide a toner for developing electrostatic images with little environmental variation in the amount of triboelectric charge even when polyester is used as the binder resin.

[Structure of the Invention] One feature of the electrostatic image developing toner of the present invention is that it contains a metal compound of a salicylic acid derivative having at least one carboxyl group or sulfoxyl group as a substituent as a charge control agent.

As a result of studies conducted to achieve the above object, the present inventor found that by using a metal compound of a salicylic acid derivative having a carboxyl group or a sulfoxyl group as a substituent, when silica fine powder is externally added, the amount of triboelectrification increases. It was confirmed that a toner with less environmental dependence could be obtained.

The present invention was completed based on such knowledge.

Examples of the metal compound of the salicylic acid derivative in the present invention include the following compounds.

The salicylic acid derivative metal compound having a carboxyl group or sulfoxyl group of the present invention is characterized by a sufficiently high amount of triboelectrification, and, contrary to general compounds, it is reduced in low temperature and low humidity processes. The cause of this is unknown, but
It is thought that the carboxyl group or sulfoxyl group introduced as a substituent is acting.

Due to these properties of the metal compound of the salicylic acid derivative having a carboxyl group or a sulfoxyl group of the present invention, the toner using the charge control agent of the present invention has a triboelectric charge that varies depending on temperature and humidity when silica is externally added. Fluctuations are extremely low F. The reason for this is that the effect of silica, which increases the amount of frictional electrification at low temperatures and low humidity, is compensated for by the effect that the metal compound of the salicylic acid derivative having a carboxyl group or sulfoxyl group of the present invention reduces the amount of triboelectric electrification at low temperatures and low humidity. This is thought to be because of this.

Methods for incorporating the metal compound of the salicylic acid derivative of the present invention into the toner include a method of adding it inside the toner and a method of adding it externally. In the case of internal addition 1. The amount of the charge control agent of the present invention is determined by the type of binder resin, the amount added if necessary, and the toner manufacturing method, and is not uniquely limited. 0.1~
It is used in an amount of 20 parts by weight, preferably 0.5 to 10 parts by weight.

In addition, when adding externally, 0.0 parts by weight per 100 parts by weight of resin.
It is preferably 1 to 101 parts by weight, and is preferably mechanochemically fixed to the surface of the f1 particle.

Further, conventionally known charge control agents can be used in combination with the charge control agent of the present invention to the extent that they do not have any adverse effects.

In addition, fine silica powder, which is an essential component of the present invention, is externally added as a fluidity imparting agent.

The amount of triboelectric charging of toner becomes insufficient under high temperature and high humidity conditions, often causing a decrease in image density.For this reason, fine silica powder is treated with a silane coupling agent or silicone oil, etc. If such fine silica powder is used, the amount of triboelectric charge will be excessive under low temperature and low humidity conditions, which will also cause a decrease in image density.

However, since the metal compound of the salicylic acid derivative of the present invention has the effect of compensating for environmental fluctuations in the amount of triboelectric charge of silica, when fine silica powder is externally added to the toner containing the metal compound of the salicylic acid derivative of the present invention, triboelectric charge increases. Fluctuations in quantity become significantly smaller.

Coloring agents used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, lake,
Calco oil blue, chrome yellow, quinacridone,
Conventionally known facial cleansing agents such as benzidine yellow, rose bengal, triarylmethane dyes, heptanoazo facial cleansing agents, and disazo facial cleansing agents may also be used alone or in combination.

The binder resin used in the present invention includes polystyrene,
Monopolymers of styrene and its substituted products such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene coifl polymer, styrene-vinyl Naphthalene large polymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-
Octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-
7 Acrylonitrile copolymer.

Styrene-vinyl methyl ether co-ffi polymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-7crylonitrile-indene copolymer Styrenic copolymers such as styrene-maleic acid copolymer and styrene-maleic acid ester copolymer; polymethyl methacrylate;
Polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon Examples include resins, aromatic petroleum resins, chlorinated paraffins, and paraffin waxes, which can be used alone or in combination.

The monomer components of the polyester resin used in the present invention include the following.

Polyhydric alcohol components include ethylene glycol, propylene glycol, 1,3-butanediol, l, 4
-butanediol, 2.3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1. S-hentanediol, 1,6-hexanediol, neopentyl glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, or a bisphenol derivative represented by the following formula Diols such as

In addition, examples of the trihydric or higher alcohol include glycerin, sorbitan, and the like.

As acid components, unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or acid anhydrides thereof, co/\hydric acid, adipic acid, sepacic acid,
Examples include dicarboxylic acids such as azelaic acid or their acid anhydrides, aromatic dicarboxylic acids such as phthalic acid and terephthalic acid, and lower alkyl esters thereof.

Examples of trivalent or higher acid acids include trimellitic acid, pyromellitic acid, and their acid anhydrides and lower alkyl esters.

Further, as binder resins particularly suitable for pressure fixing, the following can be used alone or in combination.

Polyolefin (low molecular weight polyethylene, low molecular weight polypropylene, polyethylene oxide, poly-4-fluorinated ethylene, etc.), epoxy resin, polyester resin, styrene-butadiene copolymer (monomer ratio 5-30:95-7)
0), olefin copolymers (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester Daito polymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene -vinyl acetate copolymer, ionomer resin), polyvinylpyrrolidone, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin.

Further, when the toner of the present invention is used as a two-component developer, it is mixed with a carrier powder.As the carrier that can be used in the present invention, known carriers can be used, such as iron powder, ferrite powder, etc. Magnetic powder such as powder or nickel powder.

Examples include glass beads 1 and those whose surfaces are treated with resin or the like.

Furthermore, the toner of the present invention can further contain a magnetic material and be used as a magnetic toner. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides and iron such as magnetite, hematite, and ferrite.

Metals such as cobalt, nickel or with these metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium Examples include alloys with and mixtures thereof. These ferromagnetic materials have an average particle size of 0
．． About 1 to 2μ, preferably O01 to 1.0 g, is desirable, and the amount to be included in the toner is about 20 to 200 parts by weight per 100 parts by weight of the resin component, particularly preferably about 20 to 200 parts by weight per 100 parts by weight of the resin component. It is 407,150 parts by weight.

The toner of the present invention may contain additives as required. Examples of additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide,
Examples include conductivity imparting agents such as carbon black and tin oxide, fixing aids such as low molecular weight polystyrene, fluidity imparting agents such as aluminum oxide, and the like.

To prepare the toner for developing an electrostatic image according to the present invention, the charge control agent according to the present invention is mixed with a vinyl or non-vinyl thermoplastic resin, a pigment or dye as a coloring agent, a magnetic material as necessary, Additives, etc. are thoroughly mixed using a ball mill or other mixer, and then melted, summed, and kneaded using a heat kneader such as a heated roll, niegu, or extruder to make the resins compatible with each other. Alternatively, a toner having an average particle size of 5 to 20% can be obtained by dispersing or dissolving the dye, cooling and solidifying, and then crushing and classifying. Alternatively, the material can be obtained by dispersing the material in a binder resin solution and then spray-drying it, or by mixing the specified material with the monomers that should constitute the binder resin to form an emulsified suspension and then polymerizing it. A polymerization method for obtaining a toner, a toner SJ manufacturing method, a method of incorporating the toner into the core and/or shell of a so-called microcapsule toner consisting of a core material and a shell material, and the like can be applied.

The toner produced by these methods is the conventionally known 7
All of them can be used for development to visualize electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., and exhibit excellent effects as described below.

That is, the triboelectric charge of the metal compound of the salicylic acid derivative of the present invention is sufficiently high, and unlike that of conventional charge control agents, it decreases as the temperature and humidity decrease. Therefore, even if an external additive such as silica, which significantly increases the amount of triboelectric charge under low temperature and low humidity conditions, is added, fluctuations in the amount of triboelectricity of the toner due to environmental changes can be significantly suppressed. In addition, styrene with an acid value
Even if a binder resin such as an acrylic resin or polyester, which has a large amount of triboelectric charge and which decreases significantly under high temperature and high humidity, is used, environmental stability of the amount of triboelectric charge not seen in conventional toners can be obtained.

Therefore, the toner containing the metal compound of the salicylic acid derivative of the present invention can provide a high-density image with less environmental dependence, which has not been seen in conventional toners.

[Examples] Hereinafter, the present invention will be explained in detail with reference to Examples, which do not limit the present invention in any way. All parts in the following formulations are parts by weight.

Example 1 The above materials were mixed in a blender and then kneaded with two rolls heated to 130°C. After the kneaded material was left to cool naturally, it was roughly pulverized using a cutter mill, then pulverized using a pulverizer using a jet stream, and further classified using an air classifier.
A fine powder with a particle size of 5 to 20 mm was obtained.

The fine powder was collected at a ratio of 5 parts to 95 parts of the iron powder carrier having a particle size of 50 to 80μ, and was heated at high temperature and high humidity (32,
5°C, 85%), room temperature and humidity (23°C, 80%), and low temperature and low humidity (15°C, 10%) for 4 days. Thereafter, the mixture was shaken for 20 seconds under each environmental condition, and the amount of charge was measured by a blow-off method in which the carrier and the fine powder were mixed.

The results are shown in Table 1, and the triboelectric charge t: of the fine powder is
It is sufficient under all environmental conditions, and decreases as the humidity decreases.

Furthermore, 4 g of silica fine powder treated with hexamethyldisilazane was externally added to 1 kg of the fine powder. This fine powder 5i91
1, iron powder carrier 95fi with a particle size of 50 to 80μ layer
The specimens were collected at a ratio of 1, and left for 4 days under each of the above-mentioned environments. Thereafter, it was shaken for 20 seconds under each environmental condition, and the amount of charge was measured by the blow-off method.

The results are shown in Table 1, and the amount of triboelectric charge was sufficient under all environmental conditions, and the variation was very small.

Instead of the fine silica powder treated with hexamethyldisilazane, 4 g of fine silica powder treated with silicone oil was externally added to 1 kg of the fine powder. The amount of triboelectric charge of this fine powder was measured by the method described above.

The results are shown in Table 1, and the amount of triboelectric charge was sufficient under all environmental conditions, and the variation was very small.

Examples 2 to 6 Exemplified Compound 1 of Example 1 was replaced with Exemplified Compounds 2, 3.
Fine powder was obtained in the same manner as in Example 1 except that the powder was changed to 9.10.11, and the amount of triboelectric charge was measured under each environment. The results are shown in Table 1, and as in Example 1, there was a tendency for the triboelectric charge amount to decrease under low humidity.

Furthermore, the amount of triboelectric charge was also measured in the same manner as in Example 1 for fine powders in which fine silica powder treated with hexamethyldisilazane or fine silica powder treated with silicone oil was externally added to the fine powder.

As shown in Table 1, good results similar to those of Example 1 were obtained.

Comparative Example 1 A fine powder was obtained in the same manner as in Example 1, except that the exemplified compound in Example 1 was changed to the compound shown below, and the amount of triboelectric charge in each environment was measured.

The results are shown in Table 1. It shows a sufficient amount of triboelectric charge, but the amount decreases under high humidity.

Furthermore, the amount of triboelectric charge was measured in the same manner as in Example 1 for each of the fine powders in which fine silica powder treated with hexamethyldisilazane or fine silica powder treated with silicone oil was externally added to the fine powder.

The results are shown in Table 1, and the amount of triboelectric charge in an environment of 15° C. and 10% increased significantly, and environmental fluctuations increased.

Example 7 (Polyester (acid value: 10, acid value: 15) 100 parts of the material listed in E were kneaded in a blending machine, and then kneaded with two rolls heated to 110°C. After the mixed material was allowed to cool naturally, it was roughened with a cutter mill. After pulverization, it was pulverized using a pulverizer using a jet stream, and further classified using an air classifier to obtain a fine powder having a particle size of 5 to 20H.

The fine powder was collected at a ratio of 5 parts to 35 parts of iron powder carrier with a particle size of 50 to 80 knits, and
℃, 85%), normal temperature and humidity (23℃, 60%).

It was left at low temperature and low humidity (15° C., 10%) for 4 days. Thereafter, the mixture was shaken for 20 seconds under each environmental condition to mix the carrier and the fine powder, and the amount of charge was measured by the blow-off method.

The results are shown in Table 2. The amount of triboelectric charge of the fine powder was sufficient under all environmental conditions, and moreover, it decreased as the humidity became lower.

Furthermore, the amount of triboelectric charge was measured in the same manner as in Example 1 for fine silica powder treated with hexamethyldisilazane or fine powder obtained by externally adding silica fine powder treated with silicone oil to the fine powder.

As shown in Table 2, the amount of triboelectric charge was sufficient under all environmental conditions, and the variation was very small. ．．
Fine powder was obtained in the same manner as in Example 2 except that the powder was changed to 9.10.11, and the amount of triboelectric charge was measured under each environment. The results are shown in Table 2, and as in Example 2, there was a tendency for the triboelectric charge amount to decrease under low humidity.

Furthermore, in the same manner as in Example 6, the amount of triboelectrification was also measured for the fine powder to which fine silica powder treated with hexamethyldisilazane was externally added and the fine powder to which fine silica powder treated with silicone oil was externally added. .

The results are shown in Table 2, and similar to Example 6, good results were obtained.

Comparative Example 2 A fine powder was obtained in the same manner as in Example 6, except that the exemplified compound of Example 6 was replaced with the compound used in Comparative Example 1, and the amount of triboelectric charge was measured under each environment.

As shown in Table 2, at 32.5°C and high humidity of 85% F, the S friction charge is extremely low! High at 5°C and low humidity of 10%.

Further, the amount of triboelectric charge was also measured for the fine powder to which fine silica powder treated with hexamethyldisilazane was externally added and the fine powder to which fine silica powder treated with silicone oil was externally added.

The results are shown in Table 2, and compared to the case of externally adding silica powder, -
Changes in the layer environment became severe.

(The following is a blank space) Example 13 After premixing the materials listed in L, they were kneaded with two rolls heated to 150°C, and after cooling, they were roughly pulverized with a cutter mill, and then pulverized with a pulverizer using a jet stream. The mixture was further classified using an air classifier to obtain a fine powder having a volume average particle size of 11 μm.

This was mixed with 0.4 part of hydrophobic colloidal silica to obtain a toner.

The amount of triboelectric charge was measured in each environment for the toner without external addition of silica and the toner with external addition of silica. The results are shown in Table 3, and the triboelectric charge amount of the silica externally added toner is hardly affected by humidity.

When the toner of this example was subjected to a copying test using a commercially available copying machine 41 (trade name: MP-8570, Canon ■), clear images with high density were obtained in each environment.

Comparative Example 3 Exemplary compound of Example 13! instead of 3-tert-
A toner was obtained in the same manner as in Example 1, except that one part of butylsalicylic acid Cr complex was used, and a copying test was conducted.

As shown in Table 3, the triboelectric charge of the silica externally added toner increased significantly under low humidity conditions and decreased under high humidity conditions. Therefore, in low humidity conditions, images with low density and unclearness were obtained.

Example 14 A toner layer having a volume average particle diameter of 12 μm was obtained in the same manner as in Example 13 except that the material listed in L was used.

A developer was prepared by mixing 5 parts of the toner with 100 parts of iron carrier having an average particle size of 50 to 80 μm. A copying test was conducted using a commercially available electronic copying machine (trade name: MP-5000, manufactured by Canon ■).

Table 3 summarizes the triboelectrically charged acid and image density under each environment.

Because the dependence of the amount of triboelectric charge on the environment is small, high-density, clear images were obtained in each environment.

(Margin 1 below) [Effects of the Invention] Since the toner of the present invention has low environmental dependence, it can be commonly used in any environment, and can also cope with changes in the environment, so that good images can always be obtained.

Claims (2)

[Claims] (1) A developer containing a metal compound of a salicylic acid derivative having at least one carboxyl group or sulfoxyl group as a substituent as a charge control agent,
A toner for developing electrostatic images characterized by adding fine silica powder as an external additive. (2) The toner according to claim 1, wherein the silica fine powder is a silica fine powder made hydrophobic by silicone oil treatment or coupling agent treatment.