JPH0437865A - 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 in which 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 together 3 kinds of the quaternary ammonium salt, the fatty acid metallic salt, and the nigrosine dye and the charge capacity is kept equal or slightly higher than that at the time when the fatty acid metallic salt is used singly. The fatty acid metallic salt is >=2.0 wt.% of a metal contents and is 110-145 deg.C at m.p. The binder resin of the positively charged toner uses the binder resin for the toner, styrene series copolymer, polyester, and a binder resin for a pressure fixing toner. The negatively charged toner incorporates the negatively charged particles of the metal-containing complex incorporating 0.1-5 wt.% for the binder resin as the charge control agent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a developer for electrophotography, and in particular, to a developer for high quality,
Related to a developer with excellent characteristics that provides stable images at high density and does not cause retransfer or separation defects (prior art) Conventionally, as an electrophotographic method, U.S. Patent No. 2,297, 6
91, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748, a number of methods5 are known. An electrical latent image is formed on the photoreceptor by a means, then the latent image is developed using toner, and the toner image is transferred to a transfer material such as paper according to the required number of times. Copies are obtained by fixing using pressure or solvent vapor. Further, when a toner image transfer process is included, a cleaning process for removing residual toner is usually provided.

In addition, the dry toner used in these electrophotographic methods is
Two-component toners using a carrier and one-component magnetic toners containing a magnetic component are known.

Among these, negative component magnetic toners have recently been widely used because they can simplify the developing device and are easy to maintain.

(Problems to be Solved by the Invention) One-component magnetic toners generally used in dry electrophotography have conventionally contained magnetite,
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,
It is heated and melted and dispersed, 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. 58-9154,
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 and more fog, and especially low image density under high temperature and high humidity conditions.

Further, when nigrosine is used, there are problems in that the sleeve is likely to be contaminated and the latitude in selecting other materials constituting the toner is significantly narrowed.

Furthermore, in JP-A No. 61-282850, an attempt is made to achieve charging stability by using a quaternary ammonium salt and stearic acid together in a non-magnetic two-component toner, but the melting point of the fatty acid alone is too low and the toner cannot be used. Dispersion inside is bad (
Moreover, during kneading, the toner slips on the wall and shaft of the kneader, which also impedes the dispersion of magnetic substances, pigments, lubricants, etc., resulting in a toner with a lot of fog.

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, the reflection force on the image sleeve becomes stronger, which may cause a decrease in density or cause unevenness in the sleeve coat. This phenomenon becomes particularly noticeable at low temperatures and in high-speed machines, and it is inevitable that image defects will occur.

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 to have 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 because the transfer material is strongly attached to the latent image non-image area on the photoconductor on which the toner is not carried due to electrostatic attraction, making it difficult to separate the transfer material.

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 similar to two-component development using a carrier (N), problems do not occur much with developing methods that can sufficiently charge the toner. 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, the insulating small-diameter particles attached to the non-image area are sufficiently charged to the opposite polarity of the toner, so they are not transferred to the transfer material during the transfer process. Less likely to cause fog.

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 (they are transferred to the transfer material in the second transfer process, causing fog). Since the proportion of particles decreases, the problem of a decrease in image density also occurs.

Therefore, the object of the present invention is to determine the temperature, ? It is an object of the present invention to provide a developer which is not affected by the environment such as 2 degrees and which always gives high quality and stable images.

Another object of the present invention is to provide a developer that has good dispersion of magnetic materials, lubricants, etc. in resin, has excellent durability, and provides stable images without fogging or scattering even after long-term continuous use. Our goal is to provide the following.

Another object of the present invention is to provide a developer that is always stably triboelectrically charged and maintains a high concentration without contaminating a triboelectric charge imparting member 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 contains a binder resin and a magnetic material as main components, and a quaternary ammonium salt as a charge control agent. , containing 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 controllability in terms of the amount of triboelectric charge against iron powder, T6 ≧Tc≧T, ≧T.

[T, ; Charge amount of toner containing only quaternary ammonium salt (μc/g), T, ; 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), To: 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% 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 above-mentioned problems can be solved by using a developer comprising a negatively chargeable toner. They discovered this and completed the present invention.

(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, T6≧T, '&T, ≧T.

[T, , Charge amount of toner containing only quaternary ammonium salt (μc/g), Tゎ; 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), T: 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>T6 are used together, the amount of charge becomes too high under low temperature and low humidity, resulting in uneven development and
Easy to cause nausea etc.

Furthermore, when T, >Te, Te, and >Tc are used in combination, there is not much effect, and the temperature decreases by 1 degree, especially 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 satisfies 0.4≦WQ+Wp+Wゎ≦2 and 0.4≦(W
p + Wp) / Wp≦1 [Wp, quaternary ammonium salt content (wt%), Wp; fatty acid metal salt content (
Nigrosine dye content (weight %)] is preferable.

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

When Wq+Wp+Wp>2, the charge imparting member such as the developing sleeve is likely to be contaminated. Also, (w, + wn )/Wp<
At 0.2, the concentration decreases under high temperature and high humidity, and (Wp + W
p, )/WQ > 1, the image will have a lot of fog and scattering.

Further, each of Wp, Wp and w is preferably between 0.1 and 2.0% by weight.

Furthermore, 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 (
Also, the toner fluidity is poor.

Further, the melting point of the fatty acid metal salt is preferably 110°C to 145°C. If it is less than 110"C, the melt viscosity during toner kneading is too low, resulting in poor dispersion (the toner has poor fluidity, and also slips with the kneading machine, resulting in poor dispersion of the magnetic material and lubricant, resulting in images with a lot of fog. If the temperature exceeds 145° C., the toner will not be melted sufficiently during kneading (and poor dispersion will likely occur as well).

The fatty acid metal salt that satisfies the above physical properties has 10 carbon atoms.
-20 fatty acids and metals such as Aj2, Mg, and Zn are good combinations (aluminum stearate, magnesium stearate, and zinc stearate are particularly preferred).

Examples of the quaternary ammonium salt used in the present invention include those represented by the following general formula (1) or (II).

B6 In the above general formula, R1, R2, R8, 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
) I2) n-Ar, n=1-5, Ar=aryl group)
represents.

R5 represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group (-(CHa)n-Ar, n=1 to 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, phosphate ion, organic sulfate ion, organic sulfonate ion, organic phosphate ion, polyacid ion, heteropolyacid ion, carboxylic acid ion, and tetrafluoroborate. There is.

Specifically, there are the following.

(CaHz)aN” Br-1 (C4H,)4N' I- (C6)1. ,)4N” No.

(C,,H,,1N” (CH,h C1(C,,
H,,) 2N'''(CH3)2Br-shiI'I3C+aHBsN'' (CH Takayama 16 [MO?O□4]6
-CI8817N” (CHI) 81/10[H2W12
0.2]"-M Generally, methods for incorporating quaternary ammonium salts and fatty acid metal salts, which are charge control agents, into toner include a method of incorporating them inside the toner during kneading, and a method of adding them externally.
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, a method in which the toner is externally added and adhered to the toner surface afterward causes a significant decrease in density.

Further, as the binder resin used for the positively chargeable toner, when a heating pressure roller fixing device having a device for applying oil to the fixing device is used, the following toner binder resins can be used.

For example, homopolymers of styrene and its substituted products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-methyl chloromethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinylethyl 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 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. Acid, monocarboxylic acid having a double bond such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc., or a substitute thereof; for example, maleic acid, butyl maleate , methyl maleate, dimethyl maleate, etc., and their substituted products; For example, vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate, etc.; For example, ethylene, propylene, butylene. Vinyl monomers such as ethylene olefins such as; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. They may be used alone or in combination.

As the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used, such as aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, etc. For example, ethylene glycol diacrylate, ethylene glycol diacrylate, etc. , carboxylic acid esters having two double bonds such as 1,3-butanediol dimethacrylate, divinyl aniline, divinyl ether, divinyl sulfide, divinyl sulfone, and other divinyl compounds; and compounds having three or more vinyl groups; 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-dityl 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, wear 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.

5iC1s + 282+ 02 '-' Sigh
+48CI Also, in this manufacturing process, it is also possible to obtain a composite fine powder of silica and other metal-containing complexes by using other metal halide compounds, such as aluminum chloride or titanium chloride, together with the silicon halide compound. , also include them.

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 using the -1LQ reaction formula.

Na20xSiO□+ HCI + H2O= SiO
2'nH2O+ NaC1 Other methods include decomposition of sodium silicate with ammonia salts or alkali salts, generation of alkaline earth metal silicate from sodium silicate, and then decomposition with acid to form silicic acid, method of decomposing sodium silicate solution with There are methods of converting silicic acid into silicic acid using an ion exchange resin, and methods of 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 silica fine powders, the specific surface area due to nitrogen adsorption measured by the BET method is 30rrf/g or more (especially 50 to 4
00rrr/g) gives good results. Silica fine powder 0.0 per 100 parts by weight of magnetic toner
It is good to use 1 to 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 fine silica powder is added with at least one nitrogen atom in the side chain.
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 triboelectric 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.

R, R (wherein, R1 represents a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group, R2 represents an alkylene group or a phenylene group, R, and R4 represent a hydrogen atom, an alkyl group, or an aryl group, R6 indicates a nitrogen-containing 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.

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

R, -5i-Y.

(R represents an alkoxy group or a halogen, Y represents an amine group or an organo group having at least one nitrogen atom, m and n are integers from 1 to 3, and m+n=4.) Nitrogen atom Examples of the organo group having at least one group 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 unsaturated heterocyclic groups include the following.

Examples of the saturated 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, diethylaminepropyltrimethoxysilane, 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-pro and rubiberidine, trimethoxysilyl-γ-propyl mono Hollin,
There are trimethoxysilyl-γ-probylimigsol and the like.

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 in an amount of up to 5 parts by weight, it exhibits positive chargeability with excellent stability. A preferred form of addition is that 0.1 to 3 parts by weight of the treated silica fine powder is attached to the surface of the toner particles per 100 parts by weight of the positively charged 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.

Preferred silicone oils include those having a viscosity of about 5 to 5,000 centistokes at 25°C, such as methyl silicone oil, dimethyl silicone oil, phenylmethyl silicone oil, chlorphenylmethyl silicone oil, and alkyl-modified silicone oil. Preferred are silicone oil, fatty acid-modified silicone oil, polyoxyalkylene-modified silicone oil, and the like.

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.

In particular, polyvinylidene fluoride fine powder is preferred due to its fluidity and abrasive properties. 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 optionally treated with an abrasive such as cerium oxide or silicon carbide, a fluidity imparting agent such as aluminum oxide, an anti-caking agent, or a conductivity imparting agent such as carbon black or tin oxide. Other additives such as agents may also be mixed.

In addition, in order to improve mold release properties during hot roll fixing, waxy substances such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Sasol wax, paraffin wax, etc.
Adding about 5% by weight to the magnetic toner is also one of the preferred embodiments of the present invention.

Magnetic materials contained in the positively chargeable toner include iron oxides such as magnetite, magnetite, and ferrite, and iron oxides containing other metal oxides; F6. Metals such as Co, Ni, or these metals and A1, Co%Cu, Pb,
Mg, Ni, Sn, Zn%Sb, Be, B
i, Cd.

Examples include alloys with metals such as Ca, Mn, Se, Ti, and Wp, and mixtures thereof.

These ferromagnetic materials have an average particle size of about 0.1 to 2 μm,
The magnetic properties when 6e is applied to 10 are coercive force 20~150jj
e, Ila; mia conversion 50 to 200 ernu/g (preferably 5 C1 to 100 emu/g), residual magnetization 2
~200 emu/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.

Further, the average particle size of the toner is preferably 1 to 2 OL 1 m, more preferably 2 to 15 μm.

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. This is thought to be because when combined, each particle is sufficiently and uniformly charged positively and negatively.

The negatively chargeable toner used in the present invention may contain a small amount of a binder resin and negatively chargeable particles of a metal-containing complex in an amount of 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.

The metals forming the above complex include zinc, iron, chromium,
Cobalt and the like are used, and among these, chromium is preferable because it has excellent charging 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 them, binder resins having an acid value of 1 to 20 are particularly preferred.

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

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. The acid value can be adjusted by changing the monomer ratio or 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, when the temperature of olefin resins, especially polyethylene, is raised to near the melting point, oxidation occurs more quickly in the air (than in dissolved water), 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
It is carried out in accordance with IS K 007 Rho 66 r Test method for acid value of chemical products.

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 (MN) of the magnetic material in the negatively charged toner
The weight % is 0.8 M, ≦M8≦1.2 with respect to the content (M,) of the magnetic material in the positively chargeable toner.
Mp is preferred. Furthermore, it is preferable that 0.9MP≦M8≦t, IMp.

If M8 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 charging performance 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, and 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.

Further, the particle diameter (D,) of the negatively chargeable toner is 0.8D, ≦D with respect to the particle diameter (Dp) of the positively chargeable toner.
N≦2. O.D.

Furthermore, 0.9Dp≦D1≦1.5Dp Furthermore, 0.95D, ≦D2≦1.2Dp is preferred.

If D2 is smaller than 0.8D, the particle size is too small and there is no effect in assisting separation (and if DN is larger than 2.OD, the particle size is too large and damages 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 negatively chargeable toner is 0.2% to 20.0% by weight, preferably 0.5% to 10% by weight relative to the positively chargeable toner.
．． 0% by weight, more preferably 1.0% to 80% by weight
It is good to add it.

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

In the present invention, the amount of triboelectric charge is measured at a temperature/humidity of 23°C.
．． An iron powder carrier (Japanese 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 and weigh 25 cmHgO on a metal 400 mesh screen connected to an electrometer.
The amount of charge per unit weight is determined from the amount of the test substance sucked in 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 sleeve, and is made of a non-magnetic material such as aluminum, for example.
A multipolar magnet 3 is arranged inside it. By rotating one of the sleeve 2 and 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. , the developer particles stand up like a brush (magnetic brush) due to the magnetic force of the multipolar magnet 3. Until now, the positively charged toner 12 constituting the developer has been
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 image formed on the photoreceptor 5 is transferred to a transfer material 11 by a 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 by giving examples and comparative examples.

Example 1 Styrene-butyl acrylate-divinylbenzene copolymer (weight ratio 75:24.5:015) 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
00rd/g) 04 parts and spherical P with an average particle size of 0.2 μm
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, alkenylsuccinic acid, trimellitic acid, and propoxylated bisphenol (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.
After thoroughly mixing 2 parts by weight of chromium salicylate complex and 8 ingredients in a Henschel mixer, 1
Knead with an extruder set at 30°C, and 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 1
A negatively chargeable toner with a thickness of 3 μm was obtained. 6 parts by weight of this was added to 100 parts by weight of the above positively chargeable toner and mixed in a type mixer to obtain a developer of the present invention.

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 1.3
There was no fogging in the background area or inverted area, and there was little scattering.

Also, temperature below 15℃/humidity 10% and 32.5℃/85%
Similarly good results were obtained in a 20,000 copy test under the respective environmental conditions below.

Furthermore, a separability test of the transfer material was conducted. As a result, 32
．． A continuous copying test of 1,000 sheets of thin paper with a weight of 4 g per A4 size sheet was conducted in an environment of 5° C./85%, and no retransfer or separation failure occurred.

Example 2 Styrene-2-ethylhexyl acrylate-divinylbenzene copolymer (Mo/?-weight ratio 71:28.5:0
．． 5) 100 parts by weight low molecular weight propylene-ethylene copolymer 4 parts by weight magnetic iron oxide 60 parts by weight Magnesium stearate 0.5 parts by weight (melting point: 145°C
, metal content 4.5%) Nigrosine dye
A positively chargeable toner was obtained in the same manner as in Example 1 using 0.3 parts by weight of the above material.

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

Using this developer, a copying test was conducted in the same manner as in Example 1.
/20,0 under each environment of 85% and 15℃/10%
As a result of printing 00 sheets, the image density was always 1.25 or higher, no fogging was observed, and there were few skips. A separation test was also conducted in the same manner as in Example 1, but no retransfer or separation failure occurred.

Example 3 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° C. and a 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.

Further, when a separation test was conducted in the same manner as in Example 1, no retransfer or separation failure occurred.

Example 4 A copying test was conducted in the same manner as in Example 1 except that the quaternary ammonium salt was replaced with
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.

Further, when a separation test was conducted in the same manner as in Example 1, no retransfer or separation failure occurred at all.

Example 5 In Example 1, zinc stearate (melting point 123°C, metal content 10.5) was used instead of aluminum stearate.
A copying test was conducted in the same manner as in Example 1 except that the temperature was 23.5°C/humidity 60%, and the temperature was 32.5°C/60%.
20,00 under each environment of 85% below and 15℃/10% below
As a result of producing 0 images, the image density is always 1.3 or more,
No fogging was observed and there was little scattering.

Further, when a separation test was conducted in the same manner as in Example 1, no retransfer or separation failure occurred at all.

Example 6 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 scattering. 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 Example 1, 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
Re-transfer occurred on 20 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.
0, which is slightly low (in an environment of temperature 32.5°C/humidity 85%, the image density was sometimes below 0.9.
Under an environment of 5°C/10%, the density was 1.0 and fog was significant. Further, when printing was performed without replenishing toner, the image density particularly decreased, and the image density dropped to about 0.5.

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

Comparative Example 3 The same method as in Example 1 was carried out except that the quaternary ammonium salt was not used and the amount of aluminum stearate was changed to 10 parts, and the image density was 1.30 at the initial density.
When the image density was about 1,000 sheets, the image density decreased to 10, and unevenness occurred on the sleeve in an environment of 15° C./10%, making it impossible to obtain a uniform image. Moreover, there was no problem in separability.

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, it sometimes decreased by 1 degree to about 1.0. However, 15℃/
At 10% lower, the initial image density was 1.3, but there was a lot of scattering and the density gradually decreased, dropping below 0.9 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 The same method as in Example 1 was repeated except that the amount of quaternary ammonium salt was changed to 0.5 parts and the amount of aluminum stearate was changed to 1.0 parts. The image density gradually decreases and becomes less than 0.8.
The result was a rough image.

Further, fogging also occurred. When a separability test was conducted, there was no problem with separability at all.

Comparative Example 6 In Example 1, the amount of aluminum stearate was 0.
．． When carried out in the same manner except that the amount of nigrosine dye was changed to 1 part and 0.1 part, the results were as follows: 23.5°C/60% and 15%.
Although an image density of 1.20 was obtained through 20,000 images in an environment of 32.5°C/10%,
Under an 85% environment, it may fall below 1.10, and especially after being left for one night, it drops to 0.8. Further, fogging also occurred. When a separability test was conducted, there was no problem with separability 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 1.0 after 20,000 images were printed, 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.
It was found that sleeve contamination had occurred. 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 through 20,000 images, but it was as low as 1.10, 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 1.0 and 0.9 in an environment of 32.5°C/85%. Sometimes it was less than that. Also, 15℃/1
In a 0% environment, the concentration was 1.1. Further, when image formation was performed without supplying toner, the density particularly decreased, and the image density dropped to about 0.5, 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 image density was lower than that of Comparative Example 1 (only 0.8), an image with poor fluidity and a lot of fog was obtained.A separability test was performed. However, there were no problems with separability.

Comparative Example 11 In Example 1, aluminum stearate had a melting point of 1.
When the same procedure was carried out except that the temperature was 60°C and the metal content was 5.0% by weight, the image density was 1.30 due to poor aluminum stearate fraction, but at 32.5°C.
/ When left overnight in an environment of 85%, the image density was 1.
．． This resulted in a decrease to 0. 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.
Also, fogging occurred. A separability test was conducted and there was no problem with separability.

Comparative Example 13 When Example 1 was repeated except that the di-t-butylsalicylic acid chromium complex used in the negatively chargeable toner was not added, the image density was 1.10 and fogging also occurred.

Also, in an environment of 32.5℃/85%, the image density is 0.9
~0.8, and fog also 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-1-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 1.0.
Also, fogging 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 is provided which provides a stable image of high quality, high density, and has excellent characteristics that do not cause retransfer or separation failure.

[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; , separation corona discharger power supply 11, transfer material 12; positively chargeable toner 13; negatively chargeable toner 14; blade cleaner FIG.

Claims (1)

[Scope of Claims] (1) In a developer comprising a positively chargeable toner and a negatively chargeable toner, the positively chargeable toner contains a binder resin and a magnetic material as main components, and a quaternary class charge control agent is used as a charge control agent. ammonium salt, metal content is 2.0% by weight or more, and melting point is 1.
Contains a fatty acid metal salt having a temperature of 10°C to 145°C and a nigrosine dye, and each charge control property is the amount of triboelectric charge against iron powder, T_d≧T_c≧T_b≧T_a [T_a; Contains only quaternary ammonium salt. Charge amount of toner (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 has 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 (weight %), W_n: nigrosine dye content (weight %)].