JPH0437863A - developer - Google Patents

Abstract

PURPOSE:To obtain an image having high-definition and high density by using a developer constituted of a positively charged toner consisting of 3 kinds of a quaternary ammonium salt, a fatty acid metallic salt and a nigrosine dye as a positively charge control agent and a negatively charged toner incorporating a metal-containing complex as a charge control agent in a binder resin. CONSTITUTION:The positively charged toner is constituted of the binder resin, a magnetic body and the charge control agent. The charge control agent uses 3 kinds of the quaternary ammonium salt, the fatty acid metallic salt, and the nigrosine dye and the charging quantity is kept equal or slightly higher than that using singly the fatty acid metallic salt. The resin acid metallic salt is >=2.0 wt.% of a metal contents and the m.p. is 110-145 deg.C. The binder resin of positively charged toner is 1-20 in an acid value. The negatively charged toner incorporates the negatively charged particles with 0.1-5 wt.% of the metal- containing complex for the binder resin.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a developer for electrophotography, and in particular to a developer for electrophotography.

Related to a developer with excellent characteristics that provides stable images with high quality and high a degree, and does not cause retransfer or separation defects (prior art) Conventionally, as an electrophotographic method, U.S. Patent Nos. 2,297 and 6
91, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, a number of methods are known. An electrical latent image is formed on the photoreceptor, then the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, followed by heating, pressurization, solvent vapor, etc. It is used to fix images and obtain copies. Further, when a toner image transfer process is included, a cleaning process for removing residual toner is usually provided.

Further, known dry toners used in these electrophotographic methods include two-component toners using a carrier and one-component magnetic toners containing a magnetic component.

Among these, -component magnetic toner has recently been widely used because the developing device can be simplified and maintenance is easy.

(Problem to be Solved by the Invention) Generally speaking, one-component magnetic toner used in dry electrophotography has conventionally contained magnetophyte in a binder resin made of natural or synthetic resin.
Fine powder in which charge control agents, lubricants, etc. are dispersed is used.

Examples of positive charge control agents contained in such one-component magnetic toner include quaternary ammonium compounds, organic dyes,
Particularly basic dyes and their salts, nigrosine base and nigrosine dyes are often used as common positive charge control agents. These are usually added to thermoplastic resins,
The fraction is heated and melted, and then finely pulverized and adjusted to an appropriate particle size as necessary for use.

However, these charge control agents tend to cause changes in charge control properties due to mechanical shock, friction, changes in temperature and humidity conditions, and the like. Therefore, when a magnetic toner containing these as a charge control agent is used for development in a copying machine, the toner may deteriorate during use as the number of copies increases.

In particular, when a nigrosine dye is used, it tends to contaminate charge-imparting members such as a developing sleeve or to cause a decrease in density due to an increase in the amount of charge under low temperature and low humidity conditions, and the image is often scattered.

For example, JP-A-49-51951, JP-A-54-1344
No. 41, No. 54-158932, No. 56-16434
No. 9, No. 57-119364, No. 5g-9154,
No. 58-98742, No. 60-169857, No. 6
Publications such as No. 2-71968 and No. 62-87974 disclose a method using a quaternary ammonium salt, and it was possible to obtain a practically sufficient image in a two-component toner using a carrier. However, when these quaternary ammonium salts are used in -component magnetic toners, they have the drawbacks of lower density than nigrosine, more fog, and lower image density especially at high temperatures.

Also, when using nigrosine, the sleeve may be easily contaminated (
However, there is a problem in that the latitude in selecting other materials constituting the toner is significantly narrowed.

Furthermore, in JP-A-61-282850, it is attempted to achieve charging stability by using a quaternary ammonium salt and stearic acid in combination in a non-magnetic two-component toner.
Fatty acids alone have a low melting point (too low to disperse into the toner), and also slip on the kneading wall and shaft during kneading, inhibiting the dispersion of magnetic materials, pigments, lubricants, etc., and creating toners with a lot of fog. It becomes.

As a way to solve these problems,
Publication No. 1901 and other documents disclose a method of modifying basic nigrosine with higher fatty acids and using it as a charge control agent, but it is difficult to control the amount of charge, and the charge often becomes overcharged, resulting in scattering and roughness on the image. There are cases.

In addition, there is a strong reflection force on the image sleeve, which may cause a decrease in density or cause unevenness in the sleeve coat. This phenomenon is particularly noticeable in low humidity environments or on high-speed machines, and may cause image defects. is unavoidable.

Furthermore, Japanese Patent Application Laid-Open No. 59-137955 discloses a method of preventing contamination of sleeves, photoreceptors, etc. with toner and imparting uniform positive chargeability to the toner by containing a positive charge control agent and a fatty acid derivative. is proposed. Although this method is effective in preventing contamination, it still tends to cause excessive charging.

Therefore, there is a need for a positively chargeable toner that exhibits good development characteristics under all environments. Furthermore, in electrophotography, the development process is followed by a transfer process and a separation process. For this reason, toners are required not only to have good development properties (but also good transfer and separation properties).

The toner image obtained on the surface of the photoreceptor through development is transferred by applying an electric charge of opposite polarity to the toner to the back side of the transfer material using a corona discharger or charging roller placed opposite the photoreceptor through the transfer material. The image is transferred onto a material, and this transfer material is further separated from the photoreceptor. One method of separating the transfer material from the photoconductor is to use a separation claw or a separation belt, but these methods may damage the transferred image or form an image on the edges of the transfer material. There are some drawbacks such as not having one.

On the other hand, separation methods that do not make contact with the transfer material, such as a method of separating by suction from the back side of the transfer paper or a method of separating by applying corona discharge to eliminate the charge on the back of the transfer paper, have the above disadvantages. This is an excellent method in that it solves the problem.

However, with these separation methods, separation of the transfer material becomes difficult when the transfer material is thin or in an environment where the transfer material easily deforms by following the shape of the photoreceptor (especially in a high temperature environment when the transfer material is paper). This poses a problem in that the transferred image returns to the photoreceptor (referred to as re-transfer development), leading to development in which a portion of the image is missing, and paper jams due to poor separation. This is thought to be due to the fact that the areas on the photoconductor where no toner is on the latent image non-image area cause the transfer material to adhere strongly due to electrostatic attraction, making it difficult to separate.

In order to improve this problem, small insulating particles with an average particle size of 10 to 30 μm, which are charged with the opposite polarity to the toner, are attached to the non-image area of the electrostatic latent image before the transfer process, and the electrostatic latent image is attached to the non-image area of the photoreceptor. A method has been proposed in which the adsorption force with the transfer material is weakened to facilitate separation of the transfer material (Japanese Patent Application Laid-Open No. 56-60470).

Among these, we proposed a method that uses a developing device that attaches small insulating particles in addition to a developing device that forms toner images as one method for attaching small insulating particles that are charged to the opposite polarity to the toner. However, this method is undesirable because it complicates and enlarges the mechanism of the main body of the copying machine. Another method has been proposed in which small insulating particles charged to the opposite polarity to the toner are mixed with the toner in advance and adhered to the non-image area of the electrostatic latent image during toner development. This method is superior to the above method in that it does not require a separate device for depositing small insulating particles that are charged to the opposite polarity to the toner.

In this method, toner particles are mixed with insulating small-diameter particles that have the opposite polarity to the toner, so problems do not occur much in development methods that can sufficiently charge the toner, such as two-component development using a carrier. do not have.

In the two-component development method, the toner particles and the insulating small-diameter particles with the opposite polarity to the toner can each be sufficiently charged, and the toner particles are carried on the image area, while the latent image is sufficiently charged on the non-image area. Small, electrically charged insulating particles adhere to the particles and aid in separation. In addition, since the insulating small-diameter particles attached to the non-image area are sufficiently charged to the opposite polarity of the toner, they are not transferred to the transfer material during the transfer process, causing fog that deteriorates the non-image area of the transfer material. is difficult to occur.

However, since the -component development method does not use a carrier, its ability to impart charge to the toner is lower than that of the two-component development method.

For this reason, when a mixture of toner particles and insulating small-diameter particles having a polarity opposite to that of the toner is used in a -component development system, the number of particles that are not sufficiently charged increases compared to when used in a two-component development system. These poorly charged particles adhere to the non-image area of the latent image, and although they assist in separation, they are not sufficiently charged and are transferred to the transfer material during the transfer process, causing fog. Furthermore, since the ratio of sufficiently charged toner particles decreases, the problem of a decrease in image a degree also occurs.

Therefore, an object of the present invention is to provide a developer that is not affected by the environment such as temperature and provides a stable image of high quality at all times.

Another object of the present invention is to improve the dispersion of magnetic substances, lubricants, etc. in resin, to provide excellent durability, and to provide stable images without fogging or skipping even after long-term continuous use. The objective is to provide a developer.

Another object of the present invention is to provide a developer that is always stably triboelectrically charged and maintains a high concentration without contaminating triboelectrically charging members such as a developing sleeve.

Furthermore, another object of the present invention is to prevent retransfer or separation failure from occurring even if a non-contact separation method is used in the process of separating the photoreceptor and transfer material, without being affected by the environment or the quality of the transfer material. The objective is to provide a developer that does not require

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a developer comprising a positively chargeable toner and a negatively chargeable toner, wherein the positively chargeable toner has an acid value of 1 to 1.
20, a binder resin and a magnetic material as main components, a quaternary ammonium salt as a charge control agent, and a fatty acid metal salt having a metal content of 2.0% by weight or more and a melting point of 110°C to 145°C. and nigrosine dye, and each charge control property is the amount of triboelectric charge against iron powder, T, ≧Tc≧Ttl≧T.

[T, ; Charge amount of toner containing only quaternary ammonium salt (μc/g), Tb; Charge amount of toner containing only fatty acid metal salt (μ
c/g), Tc: Charge amount (μc/g) of toner containing quaternary ammonium salt, nigrosine dye, and fatty acid metal salt, To: Charge of toner containing only nigrosine dye! (
μc/g), and the negatively chargeable toner contains a binder resin as a main component, and contains a metal-containing complex as a charge control agent in an amount of 0.1% by weight or more based on the binder resin. This developer is characterized by being a negatively chargeable toner containing 5.0% by weight.

(Function) As a result of intensive investigation into the problems of the prior art described above, the present inventors have developed a quaternary ammonium salt, which has been conventionally used as a positive charge control agent, and which has a higher chargeability than the quaternary ammonium salt. A positively chargeable toner that uses a specific fatty acid metal salt having a nigrosine dye and a nigrosine dye as a positive charge control agent in a specific ratio, and a binder resin as a main component, and a metal-containing complex as a charge control agent. The present invention has been completed based on the discovery that the above-mentioned problems can be solved by using a developer comprising a negatively chargeable toner.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The positively chargeable toner constituting the developer of the present invention includes a binder resin, a magnetic material, and a charge control agent.

First, the quaternary ammonium salt, fatty acid metal salt, and nigrosine dye contained as the charge control agent have charge control properties in terms of the amount of triboelectric charge against iron powder. ≧Tc≧Tb≧T.

[T, ; Charge amount of toner containing only quaternary ammonium salt (μc/g), ■,; Charge amount of toner containing only fatty acid metal salt (μ
c/g), Tc: Charge amount of toner containing quaternary ammonium salt, nigrosine dye, and fatty acid metal salt (μc/g), Td: Charge amount of toner containing only nigrosine dye (
μc/g), and is characterized in that the three types are used in combination to control the amount of charge to a level that is equal to or slightly higher than when the fatty acid metal salt is used alone.

On the other hand, when T, >Tb and Tc>T, when used in combination, the amount of charge becomes too high under low temperature and low humidity, which tends to cause uneven development, dark density, etc.

Furthermore, when T, >Tc, or T, >T, there is not much effect when used in combination, and the concentration decreases particularly when left at high temperatures.

Further, when a quaternary ammonium salt and only a nigrosine dye are used together, significant fogging occurs, and when only a nigrosine dye and aluminum stearate are used together, the amount of charge becomes too high, resulting in uneven development and a decrease in density, especially at low temperature and low humidity.

Here, the charge amount of the positively chargeable toner is 10.0 μc/g
It is preferable that it is less than 13.0 μc/g.

Further, in the positively chargeable toner, the content of quaternary ammonium salt, fatty acid metal salt, and nigrosine dye in the toner is 0.4≦Wp + Wp + Wpl≦2 and 0.4≦
(Wp+Wp,)/Wq:i; 1[111,; Quaternary ammonium salt content (wt%), W9: Fatty acid metal salt content (wt%), Wo: Nigrosine dye content (wt%)
)] is preferable.

When Wp+Wp+Wp<0.4, the charging is too low, resulting in low concentration and insufficient durability, and poor dispersion is likely to occur, causing fog.

When Wp+Wp+Wn>2, the charge imparting member such as the developing sleeve is likely to be contaminated. Also, (wp+w, )/Wp<
At 0.2, the concentration decreases under high and high temperatures, and (Wp + W
p)/WQ>1te results in an image with a lot of fog and scattering.

Also, Wp, Wp and W. Each is preferably between 0.1 and 2.0% by weight.

Further, the metal content of the fatty acid metal salt used in the positively chargeable toner is preferably 2.0% by weight or more.

If it is less than 2.0% by weight, the concentration tends to decrease under high temperature and high humidity conditions, and the toner fluidity is also poor.

Further, the melting point of the fatty acid metal salt is preferably 110°C to 145°C. If it is below 110°C, the melt viscosity at the time of toner cross-talk is too low, resulting in toner with poor dispersion and poor fluidity, and may also cause slippage with the cross-wire machine, resulting in poor dispersion of magnetic materials and lubricants (
This results in an image with a lot of fog. If the temperature exceeds 145℃, will the toner be mixed? There are not enough nemesis, and it is easy to cause fractional defects.

The fatty acid metal salt that satisfies the above physical properties has 10 carbon atoms.
~20 fatty acids and metals such as Aρ, Mg, and Zn are preferably combined, and aluminum stearate, magnesium stearate, and zinc stearate are particularly preferred.

As quaternary ammonium salts used in the present invention, there are those represented by the following formula (I) or (II).

K! In the above-mentioned pattern, R1, R2, R3, and R4 are hydrogen atoms, alkyl groups having 1 to 30 carbon atoms, aryl groups that may have substituents on the aromatic ring, and aralkyl groups (-(C
Hz), -Ar, n=1-5, Ar=aryl group).

R5 represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group (-(CL), -Ar, n=1-5, Ar=aryl group).

R6 represents an alkyl group having 1 to 10 carbon atoms, and there may be a plurality of substituents.

A- represents an anion. Examples of anions include heroion, sulfate ion, nitrate ion, borate ion, nonacid ion, organic sulfate ion, organic sulfonate ion, organic phosphate ion, polyacid ion, and heteropolyacid ion. , carboxylate ion, and tetrafluoroborate.

Specifically, there are the following.

(C6H1l)4N" Br-1 (C4H9), N" r- (C6H13+4N" N0x- (C16Hxs) N" (CHs) a C1- (C
,,H,,)2N″(CH,),B.

C,, H,, N responsible CHs)s 1/6 [MO? 0□4]
6-C,,H3,N”(CHs)31/10[H2N,
□O,,]10-I'l1 Usually, there are two methods for incorporating quaternary ammonium salts and fatty acid metal salts, which are charge control agents, into toner: a method of incorporating them inside the toner at the time of crosstalk, and a method of adding them externally. but,
In the positively chargeable toner used in the present invention, the effects of the present invention cannot be obtained unless it is added during kneading. That is, in the method of externally adding the toner and adhering it to the surface of the toner afterwards, a significant decrease of 1 degree occurs.

The binder resin used in the positively chargeable toner used in the present invention has an acid value of 1 to 2o.In the present invention, since the binder resin of the positively chargeable toner has oxidation, A negatively charged portion exists on the surface of the toner particle. This part electrostatically repels the negatively charged toner that is mixed with it,
This further reduces aggregation. This prevents charging defects caused by toner aggregation, and the relatively low charging ability of 1.
Even when used in component development methods, images with high image density and no fog can be obtained. If the acid value of the binder resin is less than 1, there will be no effect of reducing aggregation, and if the acid value exceeds 20, the positive chargeability will decrease, resulting in a decrease in image density, fogging, etc.

As the binder resin with an acid value of 1 to 2o used in the present invention,
Monomers containing acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, dimethylmaleic acid, and their acid anhydrides and/or partial esters thereof as monomer units, or olefin-based or vinyl-based monomers. Copolymers with monomers, polyesters and rosin-modified resins having carboxyl groups at the terminal or side chains,
Olefin oxides and the like are preferred.

The method for preparing the binder resin with an acid value of 1 to 20 used in the present invention varies depending on the resin, but for vinyl copolymers containing acrylic acid, methacrylic acid, etc., conventionally known bulk polymerization and other polymerization methods are used. The acid value can be adjusted by changing the monomer ratio or by changing the degree of esterification, although it may be carried out according to the law.

On the other hand, in condensation resins such as polyester, in addition to changing the ratio of diol to dicarboxylic acid, the ratio of terminal carboxyl groups decreases as polymerization progresses, so by adjusting the degree of polymerization, the acid value can be reduced. Adjustments can be made.

In addition, when the temperature of olefin resins, especially polyethylene, is raised to near the melting point, oxidation occurs more quickly in air than in water with a good amount of air dissolved, and polyethylene oxide can be obtained, so check the acid value as appropriate. All you have to do is proceed with the oxidation reaction.

In the present invention, as a method for measuring the acid value, Japanese Industrial Standard J
The test shall be conducted in accordance with IS K 007 Ro-66r Test Method for Acid Value of Chemical Products.

The above-mentioned binder resin having an acid value can be used alone as a binder resin for a positively chargeable toner. In addition, it may be used in combination with other resins, but in this case, the binder resin having an acid value is 5% of the total binder resin in the positively chargeable toner.
It is preferable that the content is 0% by weight or more.

Further, as other binder resins to be mixed, the following toner binder resins can be used when a heating and pressure roller fixing device having a device for applying oil to the fixer is used.

For example, homopolymers of styrene and its substituted products such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, and styrene-vinylnaphthalene copolymers. , styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-a
-Methyl chlormethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-
butadiene copolymer, styrene-isoprene copolymer,
Styrenic copolymers such as styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenolic resins, natural resin-modified phenolic resins, natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins,
Polyester resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral resins, tenben resins, coumaron indene resins, petroleum-based resins, etc. are used.

In the heating and pressure roller fixing method in which little oil is applied, so-called offset development, in which a part of the toner image on the toner image support member is transferred to the roller, and the adhesion of the toner to the toner image support member are important issues. be. Toners that are fixed with less thermal energy usually tend to block or cake during storage or in a developing device, so these problems must also be taken into consideration. The physical properties of the binder resin in the toner are most involved in these developments, but according to the research of the present inventors, reducing the content of magnetic material in the toner causes the toner image support to become weaker during fixing. Although the adhesion of the toner to the member is improved, offset is more likely to occur, and blocking or caking is also more likely to occur.

Therefore, the selection of the binder resin becomes more important when using a heated pressure roller fixing method in which little oil is applied for fixing. Preferred binder resins include crosslinked styrenic copolymers and crosslinked polyesters.

Examples of comonomers for the styrene monomer in the styrenic copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and methacrylate. acids, monocarboxylic acids having double bonds such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc., or substituted products thereof, such as maleic acid, butyl maleate, Dicarboxylic acids with double bonds such as methyl maleate, dimethyl maleate, etc. and their substituted substances, such as vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate, etc.; For example, ethylene, propylene, butylene, etc. Ethylene-based olefins such as vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl monomers such as vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. alone or in combination; Used above.

As the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used, such as aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol diacrylate. Carboxylic acid esters having two double bonds such as methacrylate and 1,3-butanediol dimethacrylate; Diviny compounds such as divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; and compounds having three or more vinyl groups. Compounds; may be used alone or as a mixture.

In addition, when a pressure fixing method is used for fixing, it is possible to use a binder resin for pressure fixing toners, such as polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer,
Examples include ethylene-vinyl acetate copolymer, ionomer resin, styrene-butadiene copolymer, styrene-isoprene copolymer, linear saturated polyester, paraffin, and the like.

Further, it is preferable to add fine silica powder to the positively charged magnetic toner used in the present invention. When the above magnetic toner and fine silica powder are combined, friction is significantly reduced due to the presence of the fine silica powder between the toner particles and the sleeve surface. As a result, the life of the magnetic toner and the sleeve can be extended, and stable charging properties can also be maintained, making it possible to obtain a magnetic toner that is better for long-term use.

As the fine silica powder, both fine silica powder produced by a dry method and a wet method can be used, but from the viewpoint of filming resistance and durability, it is preferable to use a fine silica powder produced by a dry method.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halide compound. For example, this method utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.

5iC14+ 2Hz÷0□→SiO2+4 HCIAlso, in this manufacturing process, by using other metal halide compounds, such as aluminum chloride or titanium chloride, together with the silicon halide compound, a composite fine powder of silica and other metal-containing complexes can be produced. It is also possible to obtain, and these are also included.

On the other hand, various conventionally known methods can be used to produce the silica fine powder used in the present invention by a wet method. For example, there is a method of decomposing sodium silicate using an acid as shown below in the general reaction formula.

NaaO'XSiO2+ HCI+HiO-5iO
a'nH2O÷NaC1 Other methods include decomposition of sodium silicate with ammonia salts or alkali salts, a method of generating alkaline earth metal silicate from sodium silicate and then decomposing it with acid to form silicic acid, sodium silicate solution There are two methods: converting silicic acid into silicic acid using an ion exchange resin, and using natural silicic acid or natural silicates.

As the silica fine powder referred to herein, any of anhydrous silicon dioxide (silica) and other silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, and zinc silicate can be used.

Among the above-mentioned silica fine powders, the specific surface area by desired absorption measured by the BET method is 30 g/g or more (especially 50 to 400 g/g).
rrf/g) gives good results. Silica fine powder 0.01 to 100 parts by weight of magnetic toner
It is recommended to use 8 parts by weight, preferably 0.1 to 5 parts by weight.

In addition, when used in the above magnetic toner, positively charged silica fine powder is used rather than negatively charged silica fine powder added to prevent toner friction and to prevent staining of the sleeve surface. This method is preferable since it does not impair charging stability.

As a method for obtaining positively charged silica fine powder, the above-mentioned untreated silica fine powder is mixed with a small number of nitrogen atoms in the side chain (both 1 and 1).
There is a method of treatment with a silicone oil having more than one organo group, a method of treatment with a nitrogen-containing silane coupling agent, or a method of treatment with both.

In the present invention, positively charged silica refers to silica that has a positive tripo charge relative to the iron powder carrier when measured by a blow-off method.

As the silicone oil having a nitrogen atom in the side chain used in the treatment of silica fine powder, a silicone oil having at least a partial structure represented by the following formula can be used.

(In the formula, R represents a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group, R2 represents an alkylene group or a phenylene group, R8 and R4 represent a hydrogen atom, an alkyl group, or an aryl group, and R5 represents a nitrogen-containing group. (represents a heterocyclic group). The above alkyl group, aryl group, alkylene group or phenylene group may have an organo group having a nitrogen atom, or may have a substituent such as halogen within a range that does not impair chargeability.

Further, the nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

Rm 5l-Yゎ (R represents an alkoxy group or a halogen, Y represents an amino group or an organo group having at least one nitrogen atom, m and n are integers of 1 to 3, and m+n: 4) ) Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent or a group having a nitrogen-containing heterocyclic group.

Examples of the nitrogen-containing heterocyclic group include unsaturated heterocyclic groups and saturated heterocyclic groups, and known ones can be used. Examples of the unsaturated heterocyclic group include the following.

Examples of the self-enclosed heterocyclic group include the following.

The heterocyclic group used in the present invention is preferably a five-membered ring or a six-membered ring in consideration of stability.

Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane. Silane, monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropyl monomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ
-Propylphenylamine, trimethoxysilyl-γ-
Propylbenzylamine, etc. Furthermore, as the nitrogen-containing heterocycle, those having the above-mentioned structure can be used. Examples of such compounds include trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl-γ-propyl monophorine, etc. ,
Examples include trimethoxysilyl-γ-propylimidazole.

The usage amount of these treated positively charged silica fine powders is as follows:
0.01 to 100 parts by weight of positively charged magnetic toner
The effect is exhibited when the amount is 8 parts by weight, particularly preferably 0.1
When added to ~5 parts by weight, it exhibits positive chargeability with high stability.A preferred mode of addition is positive i'
It is preferable that 01 to 3 parts by weight of the treated silica fine powder be attached to the surface of the toner particles based on 100 parts by weight of the fi-electric magnetic toner. Incidentally, the aforementioned untreated silica fine powder can also be used in the same amount.

In addition, the silica fine powder used in the present invention may be optionally treated with a silane coupling agent, silicone oil, a treatment agent that reacts with or physically adsorbs to the silica fine powder such as an organic silicon compound, or the like for the purpose of hydrophobization. The treatment may be performed using a combination of various treatment agents. Examples of such treatment agents include hexamethyldisilazane, vinyltrimethoxysilane, vinyltriethoxysilane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, Allyl phenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-
Chlorethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyljethoxysilane, hexamethyldisiloxane, 1.3
- divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 per molecule
Examples include dimethylpolysiloxane, which has siloxane units, and each unit located at the end contains a hydroxyl group bonded to one Si. Further, silicone oil is generally represented by the following formula.

A preferred silicone oil has a viscosity of approximately 5 to 5. ○00 centistokes are used, such as methyl silicone oil, dimethyl silicone oil, phenylmethyl silicone oil, chlorphenylmethyl silicone oil, alkyl-modified silicone oil, fatty acid-modified silicone oil, polyoxyalkylene-modified silicone oil, etc. is preferred.

These may be used alone or in a mixture of two or more.

Further, in the present invention, it is preferable to add fine powder of a fluorine-containing polymer, for example, fine powder of polytetrafluoroethylene, polyvinylidene fluoride, etc., and fine powder of tetrafluoroethylene-vinylidene fluoride copolymer.

Particularly preferred is polyvinylidene fluoride fine powder from the viewpoint of fluidity and polishability. Addition amount to toner is 0.0
1 to 2.0% by weight, especially 0.02 to 1.0% by weight is preferred.

Particularly, in the case of magnetic toner in which fine silica powder is combined with the above-mentioned fine powder, for reasons that are not clear, the state of the silica adhered to the toner is stabilized, and for example, the adhered silica is released from the toner, causing the toner to become The effect on friction and sleeve staining does not decrease, and it is possible to further increase charging stability.

In addition, the positively chargeable toner may be coated with an abrasive such as cerium oxide or silicon carbide, a fluidity imparting agent such as aluminum oxide, an anti-caking agent, or a conductive agent such as carbon black or tin oxide, as necessary. You may also mix other additives such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Sasol wax, paraffin wax, etc. for the purpose of improving mold releasability during hot roll fixing. It is also one of the preferred embodiments of the present invention to add about 0.5 to 5% by weight of a waxy substance to the magnetic toner.

The magnetic materials contained in the positively chargeable toner include iron oxides such as magnetite and magnethemite ferrite, and iron oxides containing other metal oxides: metals such as Fe, Co, and Ni, or metals containing these metals. A1, Co, Cu, Pb
, Mg, Ni, Sn, Zn, Sb, Be,
Bi, Cd, Ca, Mn, Se, Ti, Wp
Examples include alloys with metals such as (2) and mixtures thereof.

These ferromagnetic materials have an average particle size of about 0.1 to 2 μm,
The magnetic properties when 5e is applied to 10 are coercive force 20 to 150j5
e, saturation magnetization 50 to 200 emu/g (preferably 50
~100 emu/g), residual magnetization 2~200 em
U/g is desirable.

Further, the content of the magnetic material in the positively chargeable toner is 40% to 100% by weight, more preferably 5% by weight based on the binder resin.
It is 0 to 90% by weight.

In addition, the average particle size of the toner is 1 to 20 μm, and even 2 μm.
It is preferable that it is 15 micrometers.

Next, a negatively chargeable toner, which is another constituent material of the developer of the present invention, which is used in combination with the above-described positively chargeable toner, will be described.

That is, the developer of the present invention, which is a mixture of a negatively chargeable toner and the above-mentioned positively chargeable toner particles, provides a fog-free image with high image density even when used in a one-component development method with low charge imparting ability. I can do it.

The reason for this is thought to be that the positively chargeable toner, which forms part of the developer of the present invention, has excellent charge controllability and rise property to a degree never seen before.

Further, due to some kind of interaction between the charge control agent having the above-described specific structure used in the positively chargeable toner and the metal-containing complex used in the negatively chargeable toner, the positively chargeable toner and the negatively chargeable toner are combined. It is thought that this is because, especially when combined, each particle is sufficiently and uniformly charged both positively and negatively.

The negatively chargeable toner used in the present invention includes at least a binder resin, a magnetic material, and negatively chargeable particles of a metal-containing complex containing 0.1% to 5% by weight based on the binder resin. It is characterized by

If the amount of the metal-containing complex used in the above-mentioned negatively chargeable toner is less than 0.1% by weight, the magnetic particles of this toner cannot be sufficiently negatively charged, resulting in fogging, and if it exceeds 5.0% by weight, the positively chargeable toner is When used in combination with positively chargeable toner, aggregation occurs with the positively chargeable toner, resulting in insufficient charging and fogging.

As the metal-containing complex, a metal complex of a monoazo dye, a metal complex of salicylic acid, a metal complex of naphthoic acid, a metal complex of dicarboxylic acid, etc. can be used. Among these, metal complexes of salicylic acid are particularly preferred since they do not cause fogging in any environment.

Zinc, iron, chromium, cobalt, etc. are used as the metal forming the above-mentioned body, and among these, chromium is preferable because it has excellent charge build-up properties and does not cause fogging in any environment.

Further, as the binder resin used in the negatively chargeable toner, the same binder resins as those used in ordinary toners can be used, but among these binder resins having an acid value of 1 to 2o are particularly preferred.

For example, monomers containing acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, dimethylmaleic acid, and their acid anhydrides and/or partial esters thereof as monomer units, or monomers containing these and olefinic or Copolymers with vinyl monomers, polyesters having carboxyl groups at terminals or side chains, rosin-modified resins, olefin oxides, and the like are preferred.

The method for preparing these binder resins varies depending on the resin, but for vinyl copolymers containing acrylic acid, methacrylic acid, etc., conventional polymerization methods such as bulk polymerization may be used. , by changing the monomer ratio,
Furthermore, the acid value can be adjusted by changing the degree of esterification.

On the other hand, in condensation resins such as polyester, in addition to changing the ratio of diol to dicarboxylic acid, the ratio of terminal carboxyl groups decreases as polymerization progresses, so by adjusting the degree of polymerization, the acid value can be reduced. Adjustments can be made.

In addition, olefin resins, especially polyethylene, have a temperature close to their melting point (
If the temperature is raised to 1, oxidation occurs more quickly in air than in water with a good amount of air dissolved in it, and polyethylene oxide can be obtained, so the oxidation reaction can proceed while checking the acid value as appropriate.

A binder resin having an acid value can be used alone as a binder resin for a negatively chargeable toner. Further, it may be used in combination with other resins, but in this case, the binder resin having an acid value is contained in an amount of 50% by weight or more based on the total binder resin in the negatively chargeable toner. It is preferable.

Further, as the other binder resin to be mixed, the same binder resin as used in the positively chargeable toner described above can be used.

Further, it is preferable that the negatively charged toner is a magnetic toner since it does not cause problems such as scattering.

The magnetic material used at this time can be the same as that used for the positively chargeable toner described above.

In addition, the content of magnetic material in the negatively charged toner (MN
) Weight %: Content of magnetic material in positively chargeable toner (M, ) Weight %
For this, it is preferable that 0.8Mp≦M2≦1.2MP. Furthermore, it is preferable that 0.9MP≦MN≦1.1MP.

If M is smaller than 0.8 Mp, the magnetic binding force by the developing sleeve will be small, and there is a risk of scattering in a high temperature environment where the charging property is relatively reduced.

On the other hand, if MN is larger than 1.2 Mp, the magnetic binding force by the developing sleeve becomes large (the number of particles adhering to the non-image area of the latent image becomes smaller than necessary, and the effect of assisting the separation process is lost).

Furthermore, the particle diameter (DN) of the negatively chargeable toner is 0.8DP compared to the particle diameter (D, ) of the positively chargeable toner.
≦D2 ≦2. 0D.

Furthermore, 0.9DP≦DN≦1.5Dp Furthermore, 0.95DP≦D, ≦1.2Dp is preferred.

If DN is smaller than 0.8D, the particle size is too small and there is no effect of assisting separation, and if D is smaller than 2. If the OD is larger, the particle size is too large and will damage the surface of the photoreceptor.

Further, a release agent, a coloring agent, an external additive, etc. may be added to the negatively chargeable toner, if necessary. As these, those used for positively chargeable toner can be similarly used.

Further, the amount of the negatively chargeable toner is 0.2% to 20% by weight relative to the positively chargeable toner. 0% by weight, preferably from 0.5% to 10% by weight
．． It is preferable to add 0% by weight, more preferably 1.0% to 8.0% by weight.

If the amount added is less than 0.2% by weight, there will be no effect of assisting separation, and if it is more than 20.0% by weight, the aggregation of positively chargeable toner and negatively chargeable toner will be severe, resulting in fogging due to poor charging. Occur.

In the present invention, the amount of triboelectric charge is measured at a temperature/humidity of 23°C.
, in an environment of 5°C/60%, using an iron powder carrier (Japan Iron Powder EFV20) with a particle size of 200/300 mesh.
0/300) and 2/98, and this mixture
．． Precisely weigh 5 to 1.5 g (25 cm) on a metal 400 mesh screen connected to an electrometer! z
This method is based on the method of suctioning with the pressure of O and determining the amount of charge per unit weight from the amount of the sample substance suctioned at that time and the amount of charge.

Further, the order of charge amount in the present invention does not change even by conventionally known blow-off measurement methods.

Moreover, this order is more obvious in the black fine powder before silica addition and mixing.

The developer of the present invention can be used in any one-component development for visualizing electrostatic charge images in electrophotography, electrostatic recording, printing, etc. using conventionally known means.

An example of a developing, transferring, and separating apparatus used when forming an image using the developer of the present invention is shown in FIG. 1, but these are not intended to equally limit the present invention.

In FIG. 1, 5 is a photoreceptor, 2 is a developing knob, and is made of a magnetic material such as aluminum, for example.
A multipolar magnet 3 is arranged inside it. By rotating at least one of the sleeve 2 and the multipolar magnet 3, the developer is conveyed in the direction of the arrow, and the developer is regulated by the blade 1 to form a developer layer. This developer layer is brought into a state in which developer particles stand up like a brush (magnetic brush) due to the magnetic force of the multipolar magnet 3. Until now, the positively chargeable toner 12 constituting the developer
The negatively chargeable toner 13 is charged by contact with the sleeve surface.

The developer layer on the sleeve is set so as not to come into contact with the photoreceptor 5 in the developing section. A DC or AC bias voltage may be applied between the sleeve 2 and the photoreceptor 1.

At this time, only the positively chargeable toner is developed and visualized in the latent image area, and the negatively chargeable toner 13 is in the latent image non-image area.
only sticks to it. The positively charged toner formed on the photoreceptor 5 is transferred to the transfer material 11 by the transfer corona discharger 7.
transcribed into. However, at this time, since the negatively charged toner 13 is charged to the opposite polarity to the positively charged toner 12, it is not transferred onto the transfer material 11.

Furthermore, the separation corona discharger 8 removes the charge on the back surface of the transfer material, and the transfer material 11 is separated from the photoreceptor 5. At this time, the negatively charged toner 13 on the transfer material is interposed between the photoreceptor 5 and the transfer material 11, weakening their electrostatic attraction force and assisting in separation.

Transfer residual toner remaining on photoconductor 5 and negatively charged toner 1
3 is removed by the blade cleaner 14.

(Example) Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Styrene-butyl acrylate-maleic acid-n-butyl-divinylbenzene copolymer (dry) 7-weight ratio 75:
23.5:0.8:0.7, acid value: 2.5) 100 parts by weight Low molecular weight propylene-ethylene polymer Magnetic iron oxide 4 parts by weight 70 parts by weight Aluminum stearate 0.5 parts by weight (melting point:
120℃, metal content 3.4%) Nigrosine dye
0.5 parts by weight The above materials were thoroughly mixed in a Henschel mixer, kneaded in an extruder set at 130°C, cooled, coarsely pulverized in a cutter mill, and finely pulverized in a jet mill using a jet stream. The mixture was classified using an air classifier to obtain a black fine powder with an average particle size of 12 μm. Amino-modified silicone oil (viscosity at 25°C, 100 cp, amine equivalent: 80
0) treated positively charged hydrophobic dry silica (BET2
Spherical P with an average particle size of 0.2 μm and 0.4 parts (00 bo/g)
0.2 parts of VDF particles were added and mixed in a Henschel mixer to obtain a positively chargeable toner.

Furthermore, polyester resin condensed with terephthalic acid, alkene succinic acid, trimenotic acid, and propoxylated bisphenol (acid value: 1O) 100 parts by weight low molecular weight polypropylene 3 parts by weight magnetic iron oxide 60 parts by weight di-t-butyl.
2 parts by weight of chromium salicylate complex After thoroughly mixing the above materials in a Henschel mixer, 13 parts by weight
Mixed with an extruder set at 0℃, after cooling, coarsely pulverized with a cutter mill, finely pulverized with a jet mill using a jet stream, and classified with an air classifier, with an average particle size of 13
A negatively chargeable toner of μm was obtained. This is positively charged toner 1
The developer of the present invention was obtained by adding 6 parts by weight to 00 parts by weight and mixing in a type mixer.

A commercially available electrophotographic copying machine NP-554 uses an electrostatic separation method using a corona charger as a separation method for this developer.
A copying test of 20,000 copies was conducted at 0 (40 copies/min, manufactured by Canon). During the test, the image density was always 13 or higher, no fogging was observed in the background area or inverted area, and there was little scattering.

Further, similarly good results were obtained in a copying test of 20,000 sheets under the environmental conditions of 15° C./10% humidity and 325° C./85% humidity.

Furthermore, we conducted a separation test of the transfer material. The results showed that A4 size 1
A continuous copying test of 1,000 sheets of thin paper with a weight of 4 g per sheet was conducted, but no retransfer or separation failure occurred.

Example 2 Instead of the binder resin with an acid value of 2.5 used in Example 1, a styrene-butyl acrylate-n-butyl maleate-divinylbenzene copolymer (1,000 mer weight ratio 75
:19.3:5.0:0.7, acid value: 15) was carried out in the same manner as in Example 1. 5℃/8
20,000 under each environment of 5% below and 15℃/10% below
As a result of image printing, the image density is always 1.30 or higher,
No fogging was observed and there was little scattering. A separation test was also conducted in the same manner as in Example 1, but no retransfer or separation failure occurred.

Example 3 Styrene-2-ethylhexyl acrylate-n-butyl maleate-divinylbenzene copolymer (weight ratio 70:28.5+1.0:0.5, acid value: 3, O
> 100 parts by weight low molecular weight propylene-ethylene copolymer (molecular weight 6,000)
4 parts by weight magnetic iron oxide
60 parts by weight Nigrosine dye 0.
3 parts by weight Magnesium stearate 0.5 parts by weight (melting point: 145°C, metal content 4.5%) The above material was used in the same manner as in Example 1, and the temperature was 23.5°C.
/humidity 60% below, 32.5℃/85% below and 15℃/1
As a result of printing 20,000 images under each environment below 0%, the image density was always 1.30 or higher, no fogging was observed, and there was little scattering. A separation test was also conducted in the same manner as in Example 1, but no retransfer or separation failure occurred.

Example 4 A developer of the present invention was obtained in the same manner as in Example 1 except that aluminum stearate was replaced with aluminum stearate having a melting point of 140'' and a C1 metal content of 4.0% by weight.

When a copying test was conducted on this in the same manner as in Example 1, 20,000 sheets were printed under each environment of temperature 23.5°C/60% humidity, 32.5°C/85% humidity, and 15°C/10% humidity. As a result of image printing, the image density was always 1.3 or higher, no fogging was observed, and there was little scattering.

In addition, when a separation test was conducted in the same manner as in Example 1,
No retransfer or separation defects occurred.

Example 5 A copying test was carried out in the same manner as in Example 1, except that the quaternary ammonium salt was changed to Nyyoku.
As a result of printing 20,000 images under each environment of 15° C./10% lower and 15° C./10% lower, the image density was always 1.3 or higher, no fogging was observed, and there was little scattering.

In addition, when a separation test was conducted in the same manner as in Example 1,
No retransfer or separation failure occurred.

Example 6 A developer of the present invention was obtained in the same manner as in Example 1 except that aluminum stearate was replaced with zinc stearate having a melting point of 123° C. and a metal content of 10.5% by weight.

A copying test was conducted in the same manner as in Example 1, and 20,000 images were printed under each environment of temperature 23.5°C/60% humidity, 325°C/85%, and 15°C/10%. As a result, the image a degree was more than 1.3, no fogging was observed, and there were few defects.

In addition, when a separation test was conducted in the same manner as in Example 1,
No retransfer or separation failure occurred.

Example 7 Styrene-butyl acrylate-butyl maleate/divinylbenzene copolymer (Mo/?-weight ratio 73/24/
310.4. Acid value 10) 100 parts by weight Low molecular weight polypropylene 3 parts by weight Magnetic iron oxide
60 parts by weight Di-t-butyl salicylic acid chromium complex 2 parts by weight The above materials were prepared in the same manner as in Example 1, with an average particle diameter of 12 μm.
A negatively chargeable toner was obtained.

This was mixed with the positively chargeable toner used in Example 1 in the same manner as in Example 1 to obtain a developer of the present invention.

When a copying test was conducted using this developer in the same manner as in Example 1, the image density was always 1.3 or higher during the test.
No fogging was observed in the background area or inverted area, and there was little skipping. Also, below 15/10% and 32.5℃/85%
Similarly good results were obtained in the 20,000 copy test under each of the following environments.

Furthermore, a separability test was conducted in the same manner as in the example work, but
No retransfer or separation failure occurred.

Comparative Example 1 A comparative developer was obtained in the same manner as in Example except that the negatively chargeable toner was not added.

When a copying test was conducted using this developer in the same manner as in Example 1, good results were obtained as in Example 1.

Furthermore, when a separability test was conducted in the same manner as in Example 1, 1
Retransfer occurred on 1S out of ,000 sheets.

At this time, no toner particles were observed in the non-image area on the transfer paper or the photoreceptor.

Comparative Example 2 When the same method as in Example 1 was carried out except that aluminum stearate was not used, the image density was 1.
1, which is a little low, and in an environment of temperature 32.5° C./humidity 85%, the image density sometimes became 1.0 or less. Also, 1
Under an environment of 5° C./10%, the density was 1.1 and fog was significant. Furthermore, when an image was printed without replenishing toner, the density particularly decreased, and the image density dropped to about 0.6.

Furthermore, when a separability test was conducted, no retransfer or separation failure occurred.

Comparative Example 3 In Example 1, except that the quaternary ammonium salt was not used and the amount of aluminum stearate was 1.0 parts,
When the same method was used, the initial density of the image was 1.3.
0 is i, image density is 1.05 when printing about oooo images.
In an environment of 15° C./10%, unevenness occurred on the sleeve and a uniform image could not be obtained. or,
Separability was not a problem.

Comparative Example 4 The same method as in Example 1 was carried out except that the quaternary ammonium salt and aluminum stearate were not used and nigrosine dye was used in 2 parts. The image density was 1.3 at the initial stage. However, as the number of durable sheets increased, the density sometimes decreased slightly to about 1.15. However, 15℃
At lower than /10%, the initial image density was 1.3, but there was a lot of scattering and the density gradually decreased, dropping below 1.0 and resulting in a rough image.

Furthermore, fogging occurred under each environment. A separability test was conducted and there was no problem with separability.

Comparative Example 5 In Example 1, the amount of quaternary ammonium salt was 0.5 parts,
When the same method was used except that the amount of aluminum stearate was 0 parts, the image density gradually decreased to below 10 at 15°C/10% YJ, resulting in a rough image. Ta.

Further, fogging also occurred. When a separability test was performed, the separability was perfect (no problems).

Comparative Example 6 In Example 1, the amount of aluminum stearate was 0.
．． 1 part, and the amount of nigrosine dye was 0. When carried out in the same manner except for using 1 part, the results were as follows: 23.5°C/60% and 1 part.
At 5℃/10%, an image density of 1.20 was obtained through 20,000 images, but at 32.5℃
/85% environment, it may fall below 1.2, and especially after being left for one night, it drops to 0.9. Further, when a zero separation test was conducted in which fogging occurred, there was no problem in separation at all.

Comparative Example 7 The same method as in Example 1 was carried out except that the amount of quaternary ammonium salt was 2.0 parts, the amount of aluminum stearate was 1.5 parts, and the amount of nigrosine dye was 1.0 parts. However, when the positively chargeable toner was mixed, slipping occurred and sufficient shear was not achieved.

When I created an image using this developer, the initial image density was 1.3.
0, but it decreased to 1.10 after printing 20,000 images, and there was a lot of fog. After cleaning this developing sleeve with a solvent and printing an image, the image density recovered to 1.30, indicating that the sleeve was contaminated. A separability test was conducted and there was no problem with separability.

Comparative Example 8 In Example 1, zinc stearate (melting point 123°C, metal content 10.5
When the same method was used except that the nigrosine dye was not used, the image density was stable over 20,000 images, but it was low at 1.15, and fogging occurred. . When a separability test was conducted, there was no problem in separability.

Comparative Example 9 When the same method as in Example 1 was carried out except that aluminum stearate and nigrosine dye were not used, the image density was as low as 1.10, and in an environment of 32.5°C/85% it was 1.0. Sometimes it was less than that. Also, 15℃/
In a 10% environment, the concentration was 1.2. Further, when image formation was performed without supplying toner, the density particularly decreased, and the image density dropped to about 0.6, and fogging also occurred.

A separability test was conducted and there was no problem with separability.

Comparative Example 10 In Example 1, quaternary ammonium salt and nigrosine dye were not used, and the amount of aluminum stearate was 1.0.
When the same method was used except that the image density was 0.9, which was lower than that of Comparative Example 1, only an image with poor fluidity and a lot of fog was obtained. A separability test was conducted and there was no problem with separability.

Comparative Example 11 In Example 1, aluminum stearate had a melting point of 1.
When the same procedure was performed except that the temperature was 60°C and the metal content was 5.0% by weight, the dispersion of aluminum stearate was poor (the image density was 1.30, but at 32.5°C
/ When left overnight in an environment of 85%, the image density was 1.
, 10. Further, fogging also occurred. A separability test was conducted and there was no problem with separability.

Comparative Example 12 The same procedure as in Example 1 was carried out except that an insoluble monoazo pigment was used instead of the di-t-butyl chromium salicylate complex used in the negatively chargeable toner, and the image density was 1.
．． 20, and fogging also occurred.

Also, in an environment of 32.5℃/85%, the image density is 1.0.
5, and fogging also occurred. A separability test was conducted and there was no problem with separability.

Comparative Example 13 Example 1 was carried out in the same manner as in Example 1 except that the di-t-butyl salicylic acid silica plate used in the negatively chargeable toner was not added. The image a degree was 115 and fogging occurred.

Further, in an environment of 32.5° C./85%, the image density was 09, and fogging occurred.

A separability test was conducted and there was no problem with separability.

Comparative Example 14 The same procedure as in Example 1 was carried out except that the content of the di-t-butylsalicylic acid chromium complex used in the negatively chargeable toner was changed to 8 parts by weight, and the image density was 1.20. Fog also occurred.

Also, in an environment of 32.5℃/85%, the image density is 1.1.
0, and fog also occurred.

A separability test was conducted and there was no problem with separability.

(Effects of the Invention) According to the present invention as described above, a developer with excellent characteristics that provides a stable image with high quality and high density and does not cause retransfer or separation failure is provided.

[Brief explanation of drawings]

FIG. 1 shows a schematic diagram of an example of a developing device and a transfer separation device related to the developer of the present invention. 1; Magnetic blade 2; Sleeve 3; Fixed magnet roller 4; Developing container 5: Photoreceptor 6; Alternating voltage power supply for development 7; Corona discharger for transfer 8: Corona discharger for separation 9; Power supply for corona discharger for transfer 10 : Separation corona discharger power supply 11; Transfer material 12; Positively chargeable toner 13; Negatively chargeable toner 14; Blade cleaner

Claims (1)

[Scope of Claims] (1) A developer consisting of a positively chargeable toner and a negatively chargeable toner, in which the positively chargeable toner is mainly composed of a binder resin having an acid value of 1 to 20 and a magnetic material, and is electrically charged. As a control agent, it contains a quaternary ammonium salt, a fatty acid metal salt having a metal content of 2.0% by weight or more and a melting point of 110°C to 145°C, and a nigrosine dye, each of which has charge control properties. The amount of triboelectric charge on iron powder, T_d≧T_c≧T_b≧Ta
[T_a; Charge amount of toner containing only quaternary ammonium salt (μc/g), T_b; Charge amount of toner containing only fatty acid metal salt (
μc/g), T_c: Charge amount of toner containing quaternary ammonium salt, nigrosine dye, and fatty acid metal salt (μc/g), T_d: Charge amount of toner containing only nigrosine dye (μc/g) ], and the negatively chargeable toner contains a binder resin as a main component, and contains a metal-containing complex as a charge control agent in an amount of 0.1% to 5.0% by weight based on the binder resin. A developer characterized in that it is a negatively chargeable toner containing %. (2) The content of quaternary ammonium salt, fatty acid metal salt, and nigrosine dye in the positively chargeable toner is 0.4≦W_q
+W_p+W_n≦2 and 0.4≦(W_p+W_n)/W_q≦1 [W_q; Quaternary ammonium salt content (wt%), W_
The developer according to claim 1, wherein p: fatty acid metal salt content (wt%), W_n: nigrosine dye content (wt%)].