JP2003005447A - Electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner with excellent durability and stability which does not cause an increase in contamination (fog) on a white base or decrease in the image density when the toner is repeatedly used for a copying machine, printer or the like, which does not increase the fog even when the toner is left to undergo secular change under a high temperature environment, and which does not cause scattering in the machine. SOLUTION: In the electrostatic charge image developing toner containing at least a binder resin, a coloring agent and a charge controlling agent, the coloring agent is carbon black having specific surface area of 30 to 300 m<2> /g by the BET method and the charge controlling agent is a nigrosine dye having <=1.0 wt.% Fe content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic copying machine in which an image is formed by utilizing an electrophotographic method, an electrostatic recording method, etc.
The present invention relates to toner used for developing an electrostatic latent image in a laser beam printer or the like. More specifically, the present invention relates to an electrophotographic toner having excellent copy quality, durability, and stability.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic copying machine or a laser beam printer using an electrophotographic method, an electrostatic recording apparatus using an electrostatic recording method, etc. have been used to make a copied image or a recorded image (hereinafter, both are combined. , Simply referred to as "copy image") is widely performed. For example, in an electrophotographic copying machine or a laser beam printer using the electrophotographic method, image formation is usually performed as follows. That is, first, an electrostatic latent image carrier made of a photosensitive drum such as amorphous silicon, selenium, or an organic semiconductor is positively or negatively charged by a charger, and then the charged electrostatic latent image carrier is slit exposed. Alternatively, beam exposure is performed to form an electrostatic charge image on the electrostatic latent image carrier. The formed electrostatic charge image is developed by a developer, the toner image after development is transferred to a transfer target such as paper, and the transferred toner image is fixed by a heat roll, a pressure roll or the like to form a copy image. . As a method of developing the electrostatic image,
(A) A two-component dry developing method such as a magnetic brush method or a cascade method using a two-component dry developer containing a carrier such as iron powder or glass powder and a toner containing a resin and a colorant as a main component, ( There are b) a one-component developing method in which development is performed using only toner without using a carrier, and (c) a liquid developing method using an insulating carrier liquid. The two-component developing method is generally a non-magnetic two-component developing method using an insulating non-magnetic toner containing carbon black in the toner as a black developer. The toner used in the two-component developing method and the one-component developing method usually contains a binder resin, a colorant and a charge control agent as components, and if necessary, an additive referred to as an external additive. Colored fine particles.

In these toner components, the charge control agent has the ability to impart triboelectric charging properties to the toner and holds positive or negative charges. As the positively chargeable charge control agent, there are generally quaternary ammonium salts, triphenylmethane dyes and pigments, and nigrosine dyes.
Examples of the negatively chargeable charge control agent generally include metal complexes of monoazo dyes and metal-containing dyes such as chromium-containing organic dyes.

In recent years, as a photoreceptor for an electrophotographic copying machine or a printer, a photoreceptor using an organic photoreceptor has become popular, and a positively chargeable toner is required as a developer for a copying machine or the like using the organic photoreceptor. Has been. Therefore, the positive charge control agent plays a very important role.

However, when the quaternary ammonium salt is used alone, the ability to impart triboelectric charging property to the toner is low, and when repeatedly used in a copying machine or printer for continuous copying, a white background portion called fog appears. An undesired phenomenon such as an increase in background stain (hereinafter referred to as fog) or a decrease in image density occurs.

Further, when the triphenylmethane dyes and pigments are used alone, they have the ability to impart excellent triboelectric charging properties to the toner under low temperature and low humidity and under normal temperature and normal humidity, but the charge amount decreases under high temperature and high humidity. However, an unfavorable phenomenon such as an increase in fog or a decrease in image density occurs.

On the other hand, the nigrosine dye has the ability to impart relatively excellent triboelectrification property to the toner, but the properties such as triboelectrification performance or thermal performance greatly differ depending on the manufacturing method, It is difficult to satisfy all the performance required for the toner. Further, the nigrosine-based dye has a problem that it is difficult to uniformly disperse it in the binder resin, and when it is made into a toner, the nigrosine-based dye may be dispersed or poorly distributed. Such a toner does not have a uniform charge amount distribution, and therefore exhibits excellent image characteristics at the initial stage of copying, but fog increases as the number of copies increases.

Not only the nigrosine dye but also carbon black is difficult to uniformly disperse in the binder resin, and there is a problem in that when the toner is made into a toner, the dispersion and distribution of the carbon black is defective. Toner having poor dispersion and distribution of carbon black has a non-uniform resistance value among individual particles, so that the image density is not stable or fog occurs.

Furthermore, the toner is kept at a high temperature for a long time (40-5
(0 ° C.), the surface condition of the toner causes a change with time to deteriorate the quality of the copied image, and is a numerical value indicating the ratio of the amount of the toner transferred to a transfer target such as paper. Of the toner and scattering of toner inside the copying machine or printer. That is, the image quality is excellent in the freshly manufactured state, the fog is small, the transfer rate of the toner is high, and the toner scattering in the machine is small, but the toner changes over time due to being exposed to a high temperature state for a long time. As the number of copied sheets increases, the fog increases, the transfer rate of the toner significantly decreases, and the scattering in the machine further increases. The decrease in the transfer rate is not only an economical disadvantage that a large amount of toner is used due to the fact that the proportion of toner actually transferred is low, but also a large amount of untransferred toner remains on the image carrier and excessively collects in the collecting section. This may cause the toner to fly or cause the toner to fly inside the machine. Therefore, the transfer rate is important as the required quality of toner.

Conventionally, in an attempt to improve these drawbacks,
Type and amount of colorant, amount of charge control agent, type and amount of external additive such as fluidizer and abrasive, manufacturing conditions, and in the case of two-component developer, particle size distribution of carrier particles and Although selection of materials such as resistance and selection of coating agent and improvement of combination have been made, the present situation is that satisfactory results are not always obtained.

[0011]

As described above, although the nigrosine dye is a relatively excellent charge control agent, it also has various problems. These problems are solved, the chargeability is sufficiently high, the temperature and humidity dependence during development is low, the toner properties are not deteriorated by heat stress before use, the dispersibility in the binder resin is good, and the development properties are good. There is a demand for a charge control agent which is excellent in durability and durability and a positively chargeable toner containing the same. Furthermore, there is a demand for a positively chargeable toner having good quality as described above using a nigrosine dye and carbon black in a non-magnetic black toner.

An object of the present invention is to provide a toner for developing an electrostatic charge image which solves the above problems. That is, the object of the present invention is that the triboelectric charge amount of the toner is high and stable,
An object of the present invention is to provide an electrostatic charge image developing toner that does not cause a phenomenon such as an increase in fog or a decrease in image density.

Another object of the present invention is to provide a toner for developing an electrostatic charge image, in which the triboelectric charge amount of the toner is stable without being affected by changes in temperature and humidity, and the phenomena such as fog increase and image density decrease do not occur. To provide.

Another object of the present invention is to provide a toner for developing an electrostatic charge image, which does not cause a phenomenon such as an increase in fog or a decrease in image density when used repeatedly and continuously by a copying machine or printer. It is in.

Another object of the present invention is to prevent fog from increasing even when the toner is subjected to a change with time due to being left in a high temperature environment.
There is no decrease in the transfer rate and no scattering within the machine.
An object of the present invention is to provide an excellent electrostatic charge image developing toner having durability and stability.

A further object of the present invention is that the nigrosine dye and carbon black are uniformly dispersed or compatible with each other in the binder resin, and when formed into a toner, the nigrosine dye and carbon black are poorly dispersed or distributed in the binder resin. It is an object of the present invention to provide an electrostatic charge image developing toner in which the toner is uniformly positively charged without causing the above phenomenon.

The inventors of the present invention have made it possible to stabilize the charging characteristics of the toner, improve the stability of the developing characteristics, take permanent measures against the change with time of the toner, and have good dispersibility of the nigrosine dye and carbon black in the binder resin. As a result of intensive studies to obtain distributability, the BET method has a specific surface area of 3 as a colorant.
A toner containing carbon black of 0 to 300 m ² / g and a nigrosine dye having a Fe content of 1.0% by weight or less as a charge control agent has been found to solve the above problems, and the present invention has been achieved. Is.

[0018]

Specifically, the present invention relates to the following inventions (1) to (7). (1) In an electrostatic image developing toner containing at least a binder resin, a colorant and a charge control agent, the colorant is BET.
Is a carbon black having a specific surface area of 30 to 300 m ² / g according to the method, and the charge control agent has an Fe content of 1.
The toner for developing an electrostatic charge image is characterized by containing 0% by weight or less of a nigrosine dye. (2) The toner for developing an electrostatic charge image according to (1), wherein the toner is a non-magnetic toner. (3) The toner for developing an electrostatic image according to (1) or (2), wherein the content of the nigrosine dye is 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. is there. (4) The volume average particle size of the nigrosine dye is 1 to 20 μm.
The toner for developing an electrostatic charge image according to any one of (1) to (3), characterized in that it is m. (5) The electrostatic charge image developing toner according to any one of (1) to (4), wherein the hydrophobically treated inorganic fine powder is externally added as a fluidizing agent. (6) The electrostatic charge image developing toner according to any one of (1) to (5), wherein the toner has a positive charging property.

[0019]

The present invention will be described in more detail below. The nigrosine dye of the present invention is produced, for example, by the following method. Aniline and aniline hydrochloride are used as raw materials in the presence of ferric chloride with nitrobenzene at 160 to 180 ° C.
Crude nigrosine is obtained by oxidation and reaction with. The Fe content at this time is about 4 to 6% when calculated from the residue. By adding aniline, water and sodium hydroxide to this crude nigrosine, nigrosine is subjected to a base treatment, iron chloride is dissolved and precipitated as iron hydroxide (Fe (OH) _n ) and sodium chloride is generated. At this time, sodium chloride is dissolved in the aqueous phase. By removing these iron hydroxides using a centrifugal separator such as a screw decanter or a sharp press, the amount of Fe in the dried nigrosine dye can be reduced and adjusted. Sodium chloride in the aqueous phase can be removed by separating the aqueous phase.
Finally, the nigrosine dye may be finely pulverized to a desired particle size using a pulverizer such as a jet mill.

Fe content in the nigrosine dye is 1.0%
It is important that: When the Fe content is more than 1.0%, the conductivity of the nigrosine dye becomes high, and the charge retention ability decreases. When the charge retention ability is reduced, the original function as a charge control agent is reduced, which reduces the charge amount as toner,
Problems such as an increase in fog, a decrease in image density, and scattering in the machine will occur.

Further, most of the remaining Fe component exists in the state of iron hydroxide, which makes the nigrosine dye extremely unstable. This is iron hydroxide is Fe
Fe remains in the state of (OH) ₂ and Fe (OH) _3.
(OH) ₂ is easily oxidized when exposed to air, and the dried one gradually generates hydrogen and changes to Fe ₃ O ₄ . Further, Fe (OH) ₃ is positively charged, but as it is dehydrated, it is oxidized and changed to Fe ₂ O ₃ , which weakens the polarity. As described above, the nigrosine dye is easily affected by moisture and air due to the residual iron hydroxide, and the chargeability of the dye changes. It is this Fe (OH) ₂ that deteriorates in quality due to aging when left in a high temperature environment.
It is speculated that this is largely due to the fact that the oxidation of the remaining Fe (OH) ₃ and Fe (OH) ₃ is accelerated by the high temperature.

The presence of iron hydroxide in the nigrosine dye makes it difficult to uniformly distribute it in the binder resin. This is because iron hydroxide in the nigrosine dye is present in a granular form, and the particles serve as nuclei to facilitate aggregation. Therefore, it becomes difficult to uniformly disperse and distribute the nigrosine dye in the binder resin. Particularly, when the Fe content in the nigrosine dye is more than 1.0% by weight, the amount of particles increases, and the dispersibility of nigrosine in the toner is impaired. In this case, there is a difference in the nigrosine content between the toner mother particles obtained by classification and fine powder finer than that (hereinafter referred to as classification fine powder), resulting in unevenness. Furthermore, it becomes difficult to control the content of the charge control agent even when the classified fine powder is recycled as a raw material again.

From these facts, Fe in the nigrosine dye
By setting the content to 1.0% by weight or less, the nigrosine dye can be stabilized, its resistance can be adjusted, and the aggregate in nigrosine can be removed. As a result, the toner can have good image characteristics, stability over time, and dispersibility for recycling.

The Fe content in the nigrosine dye is
You can easily find the residue by
It Among the raw materials used in the synthesis of nigrosine dye
Iron remains as the only component remaining after combustion
Is. That is, it is possible to obtain the Fe content from the residual rate.
it can. At this time, the residue is Fe₂O₃Because this
More Fe₂O₃To calculate the Fe content
it can. This is Fe (OH) in nigrosine₂In the air
Touch Fe₃ O_FourAfter changing to
Finally Fe₂O₃Becoming Fe (OH)₃Is
Fe when dehydrated ₂O₃Because it is guided by
is there. For example, about 5g of Nigrosine dye sample in a crucible
Weigh it, set the electric furnace to 800 ℃, and leave it in the air for about 2 hours.
Leave it to burn completely and measure the weight of the residue after cooling.
By doing so, the residual rate [%] is obtained. Then left
What is obtained is Fe₂O₃So this is F
It is sufficient to calculate the content by converting it into e. Fe₂O ₃Molecule
The amount is 159.7, of which the atomic weight of Fe is 55.85.
Therefore, Fe ₂Has an atomic weight of 111.7.
From this Fe₂O₃The ratio of Fe in it is 69.9%
It 69.9% of the residue rate becomes the Fe content.

The particle size of the nigrosine dye in the electrostatic image developing toner of the present invention is preferably 1 to 20 μm in terms of volume average particle size. With this particle size, dispersion and distribution in the binder resin can be improved. As a result, uneven distribution of the charge control agent in the toner does not occur, and the toner can hold a uniform and stable charge. Volume average particle size is 20
If it exceeds μm, it becomes difficult to perform good dispersion / distribution in the binder resin. That is, the content of nigrosine in the fine powder removed in the classification step during toner production (hereinafter referred to as classification fine powder) becomes larger than that in the toner mother particles, and the nigrosine content is constant when recycled and used as a raw material again. It becomes impossible to maintain the quantity. On the other hand, if it is smaller than 1 μm, the specific surface area of the nigrosine dye becomes large, which causes an excessive increase in the charge amount of the toner, resulting in a decrease in image density and a thick layer on the developer carrying member. There may be problems such as the generation of wave patterns.

The content of nigrosine in the toner can be quantified by absorbance analysis (wavelength: 567 nm).
A standard curve with a known amount of nigrosine dissolved in chloroform can be used to create a calibration curve to determine the nigrosine content of the unknown sample. By determining the content of the nigrosine in the toner mother particles, the classified fine powder, and the toner chip before fine pulverization by this quantitative analysis, the distributability of the nigrosine dye into the toner can be quantified. It can be seen that the dispersibility is good if there is almost no difference in the amount of nigrosine among the toner mother particles, the classified fine powder and the toner chips. On the other hand, it can be confirmed that when the difference in the content of nigrosine between the toner mother particles and the classified fine powder is large, poor distribution occurs.

As a method of adding the nigrosine dye in the present invention to the toner, there are a method of adding it inside the toner mother particles and a method of adding it externally. The method of adding to the inside of the toner mother particles is a general and preferable method.

The amount of nigrosine dye used in the toner is
It is determined according to the intended performance of the toner, and is not uniquely limited, but is used in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin, and 0.5 to
5.0 parts by weight is preferable for maintaining excellent chargeability.

In the present invention, in combination with the nigrosine dye, any of those conventionally used as a charge control agent can be used as an auxiliary agent. In the present invention, a positive charge control agent is mainly used, and a fatty acid metal derivative, a triphenylmethane dye, a quaternary ammonium salt (for example, tributylbenzylammonium-1-hydroxy-4-naphthosulfone) is used in combination with a nigrosine dye. Acid salt, tetrabutylbenzyl ammonium tetrafluoroborate), diorganotin oxide (eg, dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide), diorganotin borate (dibutyltin borate, dioctyltin borate, dicyclohexyltin borate), etc. be able to.

Carbon black as a colorant can be roughly classified into furnace black and channel black. The electrical properties and triboelectrification properties of the toner are affected by these types and addition amounts. Basic ones can be used for positive charging, acidic ones for negative charging,
These carbon blacks are usually used in an amount of 0.1 to 20 parts by weight, preferably 0.3 to 100 parts by weight, based on 100 parts by weight of the binder resin.
It can be used in an addition amount of 20 parts by weight.

Among the above, the carbon black used in the present invention has a specific surface area by the BET method of 30 to 300.
Those having m ² / g can find a desired effect.
Specific surface area of carbon black by BET method is 300m
^{If the amount} exceeds ² / g, the fog tends to increase, and the toner scattering in the machine tends to increase, which deteriorates the quality of the copied image. In particular, in a high temperature and high humidity environment, fogging remarkably occurs, and toner scattering in the machine occurs. Furthermore, the dispersion and distribution in the toner becomes worse. If the specific surface area is less than 30 m ² / g, it becomes difficult for the carbon black particles to sufficiently color the toner mother particles, and it becomes impossible to obtain a desired image density as a toner. A certain correlation can be found between the specific surface area of carbon black and the fog. Regarding the relationship between the specific surface area of carbon black and fog, there is a large relationship with the dispersibility of carbon black. If the specific surface area of the carbon black exceeds 300 m ² / g, it becomes difficult to uniformly disperse the toner in the toner mother particles, and the dispersion failure tends to occur. As a result, the carbon black is unevenly distributed in the toner mother particles, and the resistance value of the toner particles varies, and it becomes impossible to hold a uniform and stable charge. The larger the uneven distribution of carbon black, the more easily fog occurs. 1 of this cause
As a result, the carbon black is held around the particles of the nigrosine dye, and the charges in the nigrosine may leak through the carbon black, making it impossible to hold stable charges as toner particles. Further, since the dispersibility is impaired, the carbon black is unevenly distributed in the toner particles. If the distribution is biased, the content of carbon black in each toner particle will be different. In particular, there is a difference in the content of carbon black in the toner mother particles obtained by pulverization and classification and in the classified fine powder that is removed during classification. If the dispersibility into the toner is deteriorated as described above, the amount of carbon black becomes uneven, which makes it difficult to recycle the classified fine powder as a raw material again.

The carbon black content in the toner can be easily quantified by a method of burning the toner component stepwise in a nitrogen stream and in air. First, adjust the electric furnace sufficiently under nitrogen, and then put the sample in a container such as a crucible.
Weigh about 0 g and leave in an electric furnace. After raising the temperature to 700 ° C. in nitrogen (the amount of sample at this time is A (g)), the temperature was kept at 700 ° C. for 20 minutes and then taken out from the electric furnace. After placing in a desiccator and cooling, weigh the crucible. (The remaining sample amount at this time is B (g))
At this time, since organic components such as resin in the toner are decomposed and removed by heat, carbon black and inorganic substances remain in the crucible. Then, the electric furnace was replaced with air and the crucible was left to stand again, and the temperature in the air at 700 ° C.
After burning the sample for a minute, remove it from the electric furnace. After placing in a desiccator and cooling, weigh the crucible. (The amount of the sample remaining at this time is C (g)) Here, carbon black is burnt in air and is oxidized and thus removed,
Only inorganic substances remain. That is, it can be determined by the carbon black content (%) = [(B−C) / A] × 100 (%). The distributability of carbon black in the toner can be quantified by determining the content of carbon black in the toner mother particles, the classified fine powder, and the toner chips before fine pulverization by this quantitative analysis. Toner mother particles,
It can be seen that the dispersibility is good if there is almost no difference in the carbon black contents in the classified fine powder and the toner chips. On the other hand, it can be confirmed that when the difference in the carbon black content between the toner mother particles and the classified fine powder is large, poor distribution occurs.

Specific examples of the binder resin used in the toner of the present invention include styrene polymers such as polystyrene, poly-p-chlorostyrene, and homopolymers of styrene and its substitution products such as polyvinyltoluene. Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic copolymer, styrene-α-chloromethacrylic acid methyl ester Copolymer, styrene-vinyl methyl ether copolymer,
Styrene-vinyl ethyl ether copolymer, styrene-
Vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene diethylaminoethyl acrylate copolymer, styrene- Styrene-based copolymers such as butyl acrylate-diethylaminoethyl methacrylate copolymer, cross-linked styrene-based copolymers, etc .; polyester resins such as aliphatic dicarboxylic acids, aromatic dicarboxylic acids, aromatic dialcohols, diphenols Polyester resin having a monomer selected from the structural units as a structural unit, cross-linked polyester resin, etc .; other polyvinyl chloride, phenol resin, modified phenol resin, malein resin, rosin modified maleic resin, polyvinyl acetate Silicone resins, polyurethane resins, polyamide resins, epoxy resins, polyvinyl butyral, rosin, modified rosin, terpene resin, xylene resin, aliphatic or aliphatic hydrocarbon resins, and petroleum resins.

Examples of acrylic monomers used in the styrene acrylic copolymer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate,
(Meth) such as butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, etc.
Acrylic acid esters can be mentioned, and further, as a monomer that can be used together with them, maleic acid half esters such as acrylonitrile, methacrylonitrile, acrylamide, maleic acid, and butyl maleate, or diesters, vinyl acetate, chloride. Examples thereof include vinyl ethers such as vinyl, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone.

As the cross-linking agent used for producing the above-mentioned cross-linked styrenic polymer, a compound mainly having two or more unsaturated bonds can be mentioned, and specific examples thereof include divinylbenzene and divinyl. Aromatic divinyl compounds such as naphthalene; Carboxylic esters having two or more unsaturated bonds such as ethylene glycol diacrylate and ethylene glycol dimethacrylate; Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and unsaturated A compound having three or more bonds can be used alone or in a mixture. The cross-linking agent is used in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, based on 100 parts by weight of the binder resin.

These resins can be used alone or in combination of two or more. Of these resins, styrene polymers and polyester resins are preferable because they exhibit particularly excellent charging characteristics. The molecular weight distribution measured by GPC (gel permeation chromatography) has at least one peak in the region of 1x10 ³ to 5x10 ⁴ and at least one peak or shoulder in the region of 10 ⁵ or more. Such a molecular weight can be obtained by using a styrene-based copolymer that has the above-mentioned styrene-based copolymer, further two or more kinds of resins, for example, a combination of the styrene resin and a styrene-acrylic copolymer or a combination of two or more kinds of styrene-acrylic copolymers. A resin composition having a distribution is preferable from the viewpoint of toner pulverizability and fixing property.

Further, when the pressure fixing method is used, a binder resin for pressure toner can be used. Examples of such resins include polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, styrene-isoprene copolymer, linear saturated polyester, paraffin and other waxes.

To the toner of the present invention, an additive such as a releasing agent which is conventionally used in the production of toner can be added as long as it does not have a substantial adverse effect. As the releasing agent, for example, an aliphatic hydrocarbon that improves the releasing property (offset prevention property) at the time of heat roll fixing,
Examples thereof include fatty acid metal salts, higher fatty acids, fatty acid esters or partially saponified products thereof, silicone oil, and various waxes. Among these, the weight average molecular weight is 1
000 to 10,000, low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax,
Waxes such as carnauba wax, sazol wax and paraffin wax are preferred. These are usually 0.5-
It is added to the toner in an amount of about 5% by weight.

As the external additive used in the toner of the present invention, a fluidizing agent, an abrasive, a conductivity-imparting agent, a lubricant and the like can be used. As the base material of the fluidizing agent used in the present invention, for example, fine powder of silica, alumina, titania, magnesia, amorphous silicon-aluminum co-oxide, amorphous silicon-titanium co-oxide, etc. is used. You can Further, the fluidizing agent as an external additive has not only the purpose of imparting fluidity to the toner, but also the role of imparting and controlling the charging property of the toner. That is, the external additive adheres to the outermost surface of the toner, and thus has a great influence on the charging property of the toner.

The particles used as the fluidizing agent may be used as they are without surface treatment,
In some cases, environmental stability may be impaired due to hygroscopicity, and the fluidizing agent may adhere to the surface of the photoconductor drum to cause filming, resulting in image defects. Regarding the problem that the environmental stability due to hygroscopicity is impaired, in a high humidity environment, the fluidizing agent is affected by water, causing charge decay of the toner, causing fog on the image, and causing the toner to fly inside the machine. Will be. Therefore, the surface treatment of the particles used for the fluidizing agent is performed,
It is preferably hydrophobic. Further, by selecting a treating agent used for the surface treatment, it is possible to adjust and control the chargeability of the toner by making it have desired polarities of positive polarity and negative polarity, and stabilize the toner. It is necessary to select the surface treatment agent to be used. Examples of the surface treatment agent for the fluidizing agent used in the present invention include organoalkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane, dimethyldichlorosilane, trimethylchlorosilane, octadecyltrichlorosilane, and organochlorosilanes such as t-butyldimethylchlorosilane. , Silazanes such as hexamethyldisilazane, organoaminosilanes such as bis (dimethylamino) dimethylsilane, and silicone oil compounds can be used.

As the silicone oil type compound, straight silicone oil such as dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil or modified silicone oil can be used. The modifying group used in the modified silicone oil includes a methylstyrene group, a long-chain alkyl group, a polyether group, a carbinol group, an amino group, an epoxy group,
Examples thereof include a carboxyl group, a higher fatty acid group, a mercapto group and a methacryl group. Silicone oil has excellent releasability and slidability, and thus has the effect of preventing toner components from adhering to the surface of the photosensitive drum and filming.

As the external additives other than the fluidizing agent used in the present invention, the following publicly known lubricants, abrasives, conductivity-imparting agents and the like can be used. Examples of lubricants include polytetrafluoroethylene and zinc stearate,
Examples of the abrasive include fine powders of strontium titanate, calcium titanate, barium titanate, calcium carbonate, chromium oxide, silicon carbide, tungsten carbide, silicon nitride and the like. These abrasives have the effect of removing the toner component deposits and filming substances on the surface of the photoconductor drum by polishing and shaving them, and are used together with the fluidizing agent surface-treated with the silicone oil. Therefore, a great effect can be found. A metal oxide such as tin oxide may be added as the conductivity-imparting agent. However, these examples are merely examples, and what is added and mixed in the electrophotographic developer of the present invention is not limited to those specifically exemplified above.

The toner mother particles used in the present invention are prepared by premixing the above-mentioned toner constituents with a dry blender, a Henschel mixer, a ball mill, etc., and thereafter, the mixture is heated, kneader, uniaxial or biaxial extruded. It is preferable that the kneaded product is melt-kneaded by a heat kneader such as a ruder, the obtained kneaded product is cooled, pulverized, and, if necessary, classified into a desired particle size. However, the manufacturing method of the toner mother particles used in the present invention is not limited to this kneading and pulverizing method, for example, a method of dispersing the toner constituent material in the binder resin solution, and then spray drying,
Alternatively, any of conventionally known methods such as a method of obtaining a toner mother particle by polymerizing an emulsion suspension by mixing a predetermined material with a monomer that constitutes the binder resin may be used. Of course. The volume average particle diameter of the toner base particles used in the present invention is preferably 3 to 35 μm, more preferably 5 to 25 μm. In the case of small-sized toner mother particles, the particle size is about 4 to 15 μm.

To finally produce a toner, it is necessary to add and mix an external additive to the toner mother particles obtained as described above. Generally, an external additive is added to the toner mother particles and mixed using a Henschel mixer, a super mixer or the like. Even in this mixing step, the quality and characteristics of the toner greatly change depending on the process conditions. The controllable factors in this mixing process include the amount of filling in the mixer, the number of revolutions,
Examples include mixing time. Since the mixing conditions of the toner base particles and the external additive have a great influence on the adhesion state of the external additive on the surface of the toner base particles, it is preferable to appropriately adjust the mixing conditions.

As a final step after adding and mixing the external additive, the toner is manufactured through a sieving step for the purpose of removing foreign matters in the toner. As the type of sieve, a vibration sieving machine, an ultrasonic vibration sieving machine, a gyro shifter, or the like can be used.
At that time, since the mesh size and type of the mesh used for the sieve affect the quality of the toner, it is preferable to adjust the conditions appropriately.

The toner for developing an electrostatic charge image of the present invention can be used as a two-component developer together with a carrier. The carrier used with the toner of the present invention may be any conventionally used carrier, for example, ferromagnetic metal such as iron powder or alloy powder of ferromagnetic metal, nickel, copper, zinc, magnesium, barium, etc. Ferrite powder, magnetite powder and the like composed of elements are preferred. These carriers are styrene / acrylic copolymer, styrene / methacrylate copolymer,
It may be coated with a resin such as a styrene polymer, a silicone resin, a fluorine-containing resin or a mixture thereof. As a method of coating the carrier with a resin, a resin for coating is dissolved in a solvent, and this is coated on the core particles by a dipping method, a spray method, a fluidized bed method, etc., dried and then heated if necessary. Any known method such as a method of curing the film can be used. The average particle size of carrier particles is usually 1
Those having a thickness of 5 to 500 μm, preferably 20 to 300 μm can be used.

[0047]

EXAMPLES The present invention will be described in more detail with reference to production examples, examples and comparative examples, but the embodiments of the present invention are not limited to these examples. In the following, all parts are parts by weight.

[Production Example of Nigrosine Dye] 160 with nitrobenzene in the presence of aniline, hydrochloric acid and ferric chloride.
Oxidation and reaction were carried out at ˜180 ° C. to obtain crude nigrosine (this crude nigrosine contains the residue of ferric chloride).
Then, aniline, water and sodium hydroxide were added to the crude nigrosine, and the precipitates of nigrosine and iron hydroxide were separated by centrifugal separation with a screw decanter to remove the iron hydroxide precipitate. The obtained liquid is further washed with water and the liquid is dried,
Nigrosine dye was obtained by crushing. The Nigrosine dyes obtained are summarized in Table 1. The Fe content was adjusted by centrifuging conditions, and the volume average particle size was adjusted by changing pulverization conditions.

[0049]

[Table 1]

[Example 1] (Component) (Blending amount) Styrene acrylic copolymer 100 parts Carbon black (E) (specific surface area 133 m ² / g) 9 parts Low molecular weight polypropylene 4 parts Low molecular weight polyethylene 1 part Nigrosine dye ( A) 2 parts After uniformly mixing the above materials, kneading was performed to obtain chips, and the chips were crushed and classified to obtain positively chargeable toner mother particles having an average particle size of 11.0 μm. Next, the toner mother particles 1
0.3 parts of positively chargeable hydrophobic silica fine powder to 00 parts,
And 0.3 parts of tungsten carbide fine powder,
By mixing, a positively chargeable non-magnetic toner was obtained. 5 parts of the obtained toner and 100 parts of a carrier coated with a silicone resin having an average particle size of 100 μm were mixed using a ball mill to prepare a developer. Next, using the toner and the developer, a commercial copying machine FP7113 (manufactured by Matsushita Electric Industrial Co., Ltd.) was used to perform an actual copying test in an environment of high temperature and high humidity (30 ° C., 85% RH). At this time, the toner was heated in a dryer at 50 ° C. for 72 hours in order to facilitate confirmation of changes with time. When the obtained toner and developer were used, fog was small even after the actual copying of 80,000 sheets, the image density was stable, and no toner scattering in the machine was observed. Further, there is almost no difference in the content of the nigrosine dye and carbon black in the toner mother particles and the classified fine powder obtained by classification,
The dispersibility of the nigrosine dye and carbon black was excellent.

[0051]

[Table 2]

[Example 2] A positively chargeable non-magnetic toner and a developer were obtained in the same manner as in Example 1 except that the nigrosine dye (B) was used in place of the nigrosine dye (A) used in Example 1. It was Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner was dried in a dryer at 50 ° C. for 7 days in order to facilitate confirmation of change over time.
It heated under the condition of 2 hours. When the obtained toner and developer were used, there was little fog even after the actual copying of 80,000 sheets,
The image density was stable, and no toner was scattered inside the machine. Further, there was almost no difference in the contents of the nigrosine dye and carbon black in the toner mother particles and the classified fine powder obtained by classification, and the distributability of the nigrosine dye and carbon black was excellent.

[0053] [Example 3] Example except for using carbon black (F) (specific surface area 42m ² / g) in place of the carbon black used in Example 1 (E) (specific surface area 133m ² / g) A positively chargeable non-magnetic toner and a developer were obtained in the same manner as in 1. Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner is placed in a dryer in order to facilitate confirmation of the change over time and to identify it.
It heated at 0 degreeC and the conditions of 72 hours. When the obtained toner and developer were used, fog was small even after the actual copying of 80,000 sheets, the image density was stable, and no toner scattering in the machine was observed. Further, there was almost no difference in the contents of the nigrosine dye and carbon black in the toner mother particles and the classified fine powder obtained by classification, and the distributability of the nigrosine dye and carbon black was excellent.

Example 4 Instead of the carbon black (E) (specific surface area 133 m ² / g) used in Example 1, carbon black (G) (specific surface area 300 m ² / g) was used.
A positively chargeable non-magnetic toner and a developer were obtained in the same manner as in Example 1 except that was used. Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner was heated in a dryer at 50 ° C. for 72 hours in order to facilitate confirmation of changes with time. When the obtained toner and developer were used, fog was small even after the actual copying of 80,000 sheets, the image density was stable, and no toner scattering in the machine was observed. Further, there was almost no difference in the contents of the nigrosine dye and carbon black in the toner mother particles and the classified fine powder obtained by classification, and the distributability of the nigrosine dye and carbon black was excellent.

Comparative Example 1 A positively chargeable non-magnetic toner and a developer were prepared in the same manner as in Example 1 except that the nigrosine dye (A) used in Example 1 was replaced by the nigrosine dye (C). Obtained. Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner is placed in a drier in order to facilitate confirmation of the change over time and identify it.
The mixture was heated under the conditions of ° C and 72 hours. When the obtained toner and developer were used, high temperature and high humidity (30 ° C., 85% R
Under H), it was as good as in Example 1 until after 3,000 sheets were actually photographed, but after that, fog increased and toner scattering inside the machine began to stand out. The test was stopped after 5,000 sheets. Also,
Differences were found in the content of the nigrosine dye and the carbon black in the toner mother particles and the classified fine powder obtained by classification.

[Comparative Example 2] Instead of the carbon black (E) (specific surface area 133 m ² / g) used in Example 1, carbon black (H) (specific surface area 343 m ² / g) was used.
A positively chargeable non-magnetic toner and a developer were obtained in the same manner as in Example 1 except that Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner was heated in a dryer at 50 ° C. for 72 hours in order to facilitate confirmation of changes with time. When the obtained toner and developer were used, high temperature and high humidity (30
Under the condition of 85 ° C. and 85% RH, it was as good as in Example 1 until after 3,000 copies were actually taken, but after that, fog increased,
Toner scattering inside the machine began to stand out. The test was stopped after 5,000 sheets. Further, there were differences in the contents of the nigrosine dye and carbon black in the toner mother particles and the classified fine powder obtained by classification.

[Comparative Example 3] A carbon black (E) used in Example 1 (specific surface area 133 m ² / g) was replaced by carbon black (I) (specific surface area 25 m ² / g). A positively chargeable non-magnetic toner and a developer were obtained in the same manner as in Example 1. Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner was heated in a dryer at 50 ° C. for 72 hours in order to facilitate confirmation of changes with time. When the obtained toner and developer were used, high temperature and high humidity (30 ° C.,
Under 85% RH), the image test was stopped because the image density was low from the beginning. At this time, there was almost no difference in the content of the nigrosine dye and carbon black in the toner mother particles and the classified fine powder obtained by classification, and no problem was found in the distributability of the nigrosine dye and carbon black.

Comparative Example 4 Nigrosine dye (A) and carbon black (E) used in Example 1 (specific surface area 133)
m ² / g) was replaced with a nigrosine dye (D) and carbon black (H) (specific surface area 343 m ² / g) in the same manner as in Example 1 except that a positively chargeable non-magnetic toner and a developer were prepared. Obtained. Using this toner and developer, the same actual copying test as in Example 1 was conducted. At this time, the toner is placed in a dryer in order to facilitate confirmation of the change over time and to identify it.
It heated at 0 degreeC and the conditions of 72 hours. When the obtained toner and developer were used, high temperature and high humidity (30 ° C, 85%
Under RH), there was a lot of fog from the beginning and scattering was seen inside the plane. Further, there was a difference in the content of the nigrosine dye in the toner mother particles obtained by classification and the classified fine powder.

[0059]

By using the nigrosine dye and carbon black having a specific composition, the toner has a high triboelectric charge amount and is stable, and further, fog is increased and the image density is not affected by changes in temperature and humidity. An excellent electrostatic charge image developing toner that does not cause a phenomenon such as deterioration is obtained.

Furthermore, when repeatedly continuously copying with a copying machine or printer, fog does not increase, image density decreases, and toner components do not adhere to the surface of the photoconductor.
Even if it is subjected to aging due to being left at high temperature, fog does not increase, the transfer rate of toner does not decrease, and it does not scatter in the copying machine or printer. Excellent durability and stability. An image developing toner was obtained.

Further, the nigrosine dye and carbon black are uniformly dispersed or compatible with each other in the binder resin, and when the toner is formed into toner, poor distribution is not caused, and the toner is uniformly positively charged for electrostatic image development. Toner was obtained.

Claims (6)

[Claims] 1. An electrostatic image developing toner containing at least a binder resin, a colorant and a charge control agent, wherein the colorant is carbon black having a BET specific surface area of 30 to 300 m ² / g, and A toner for developing an electrostatic charge image, wherein the charge control agent is a nigrosine dye having an Fe content of 1.0% by weight or less. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the toner is a non-magnetic toner. 3. A binder resin 1 containing a nigrosine dye.
The toner for developing an electrostatic charge image according to claim 1 or 2, wherein the amount is 0.1 to 10 parts by weight with respect to 00 parts by weight. 4. The volume average particle diameter of the nigrosine dye is 1
4. The toner for developing an electrostatic charge image according to claim 1, wherein the toner has a particle size of about 20 .mu.m. 5. The toner for developing an electrostatic charge image according to claim 1, wherein the hydrophobically treated inorganic fine powder is externally added as a fluidizing agent. 6. The toner for developing an electrostatic charge image according to claim 1, wherein the toner has a positive charging property.