JPH03200978A - Developer - Google Patents

Abstract

PURPOSE:To obtain the developer which is ample in the reproducibility of high- density images by constituting the developer of a toner for color development having <=3.5X10<-10>s/cm electrical conductivity and a magnetic carrier coated with an amine-contg. silicone resin. CONSTITUTION:The color developer is constituted of the toner for color development having <=3.5X10<-10>s/cm electrical conductivity and the magnetic carrier coated with the amine-contg. silicone resin. The generation of an inconvenience in the coated carrier is obviated and the developer can provide the extremely good high-density images by a developing mechanism section 2 if the developer is formed by combining the toner having the low electrical conductivity and the magnetic carrier coated with the amine-contg. silicone resin as a coating resin in such a manner. The developer with which the high-density images are obtainable is obtd. in this way.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a developer and agent for electronic copying, etc., and more specifically to a two-component developer consisting of a toner and a magnetic carrier. , relates to a developer that can produce high-density images satisfactorily even when using toner with low conductivity.

(Prior Art) In the field of commercial electronic copying, magnetic brush development using a two-component magnetic developer is widely used to develop electrostatic images. As a two-component magnetic developer.

A mixture of a magnetic carrier made of powder, sintered ferrite particles, etc., and toner particles in which additives such as a colorant and a charge control agent are dispersed in a fixing resin is widely used.

A normal developing mechanism section that uses developer has a structure as shown in FIG. Supplied. The toner 6 is supplied into the lower developing device 10 through the supply port 8 with a feeder, and the toner 6 is supplied into the developing device 10 below.
A two-component developer 14 is formed by being agitated with the carrier in the developer 12 by an agitator 12.12.

Development 1) Inside the development sleeve 10 is a development sleeve (
A developer carrying member) 16 is disposed, and the developer 14 after the toner has acquired a triboelectric charge is supplied to the developing sleeve 16.
Furthermore, a magnetic brush 18 is formed on the sleeve surface by the developer. The Ia & air brush 18 is adjusted in its standing length by the ear cutting mechanism 20, and is conveyed to the nip position with the surface photosensitive layer 24 of the electrophotographic photosensitive drum (Ik carrier) 22. The photosensitive drum 22 is arranged at a distance Do-s from the developing sleeve 16, and the developing sleeve 16 and the photosensitive drum 22 are rotatably supported by an agitator (not shown) and are moved in the direction of movement (arrow) at the nip position. ) are activated so that they are in the same direction (rotation directions are opposite to each other).

A corona charger 26 connected to a variable high voltage power supply 24 and an exposure optical system 28 are arranged around the photoreceptor drum 22.
is disposed upstream of the developing device 10 to form an electrostatic latent image with a predetermined surface potential. Furthermore, a bias voltage 33 equipped with a voltage adjustment mechanism 30 is connected between the photosensitive drum 22 and the developing sleeve 12, and the photosensitive layer 2
An arbitrary bias potential 411 (bias potential) which is the same polarity as the surface potential and lower than the surface potential can be applied to the surface potential. Further, a transfer mechanism 34 is provided around the photosensitive layer 24 and downstream of the current Ik portion for transferring the toner mass to the copying machine.

In such a configuration, the developer 14 is transferred to the developing sleeve 1.
Apply a magnetic brush 18 on the photosensitive layer 2 at the nip position.
A visible toner 1 is formed on the photosensitive layer 24 by reacting with the electrostatic latent image 4.
Format &36. The formed visible image 36 is transferred to a transfer material by a transfer mechanism 34, and then the toner smear is fixed, thereby performing a direct image format.

(Problems to be Solved by the Invention) By the way, when forming a single layer, titanium oxide and chromatic pigments used in white toners and chromatic toners have lower electrical resistance (conductivity) than black pigments such as carbon. If the toner (the opposite of the It has been considered to reduce the amount of resin coating on the carrier surface to lower its resistance and thereby reduce the amount of charge on the toner.

However, conventional magnetic carriers are coated with acrylic resin, and if the resin coating amount is less than 0.01% in order to lower the resistance, the surface of the carrier core will not be sufficiently protected. There is a risk that the toner may be contaminated due to oxidation of the carrier core. In particular, in the case of a developer using white toner, the resulting image has a yellowish tinge and has poor whiteness.

In addition, in a developer where the resistance of the a-type carrier is low and the resistance of the toner is high, the resistance value of the developer changes greatly with respect to the toner concentration (T/D) (toner weight fraction in the developer). , white spots can be seen in the image even when the T/D value has decreased slightly. Moreover, it is conceivable to increase the particle size of the carrier in order to improve the white spots mentioned above.
If this is exceeded, the image quality will deteriorate and the amount of toner W4et will increase. On the other hand, if the particle size of the carrier is too small.

Coupled with the reduction in the resistance of magnetic carriers, problems that induce fireflies and carrier attraction occur.

In addition, in recent years, it has been used as a photoreceptor for electrophotography because it has good processability.
Organic photoreceptors are used, which are advantageous in terms of cost and have a large degree of freedom in functional design. There are two types of organic photoreceptors: negatively charged types and positively charged types.Negatively charged types are undesirable because they cause contamination of the copying environment and quickly deteriorate the photoreceptor. The use of positively charged organic photoconductors (OPC) is eagerly awaited.

However, the residual potential of such positively charged organic photoreceptors tends to be larger than that of conventional Ss-based negative photoreceptors, and when using positively charged organic photoreceptors, the bias potential must be 250 V or higher. An increase in the bias potential increases charge repulsion between the magnetic carrier and the developing sleeve, making carrier attraction more likely to occur. Therefore, in image formation using a positively charged organic photoreceptor and white toner or chromatic toner, there are problems in carrier attraction and improvement in image quality.

Furthermore, in order to improve the quality deterioration of W* caused by an increase in the bias potential, if the above-described distance between no and a is narrowed, stress is applied to the developer, making carrier attraction more likely to occur.

Therefore, one object of the present invention is to provide a developer that can stabilize the amount of charge of the developer within an appropriate range even when using white toner or chromatic toner with low conductivity, and has rich reproducibility of high-density images. It's about doing.

Another object of the present invention is to provide a developer that uses white toner or chromatic toner with low conductivity and is capable of producing high-density images without problems such as white spots, fireflies, and carrier drag. .

A further object of the present invention is to provide a white developer from which clear white images can be obtained.

The present invention also includes: It is an object of the present invention to provide a developer that is preferably applied to positively charged organic photoreceptors.

(Means for Solving the Problems) According to the present invention, the electrical conductivity is 3.5 x 10” sl
There is provided a color developer characterized by comprising a color developing toner having a particle size of less than am and a magnetic carrier coated with an amine-containing silicone resin.

In the present invention, the conductivity of the toner is 2. OX101
0 to 3. satisfies the range of OX 10-” 5acs, and the current value of the magnetic carrier is 0.5 to 5μ
A.

The present invention also provides that the amount of resin coating of the carrier coated with the amine-containing silicone resin is 0 with respect to the carrier core material.
．． 01 to 0.5%.

In the present invention, 50% of the weight average particle size of the carrier is further provided.
It can be characterized in that the diameter D5° satisfies the range of 70 to 90 μm.

Also in the present invention. 50% of the weight average particle size of the carrier
It can be characterized in that it is used under the conditions that the diameter D50 satisfies the range of 80 to 120 μm, the distance between the weight carrier and the developer carrier is less than 1 μm, and the development potential difference is 500 V or less, and the image carrier The body can be a positively charged organophotoreceptor.

According to the present invention, the toner can be applied to a white toner containing titanium oxide.

(Function) The present invention provides a developer by combining a toner with low conductivity and a magnetic carrier whose coat resin is a silicone resin containing aphne, thereby causing no inconvenience to the coat carrier. This is based on the knowledge that the developer can provide extremely good high-density images.

The present invention also includes: It is also known that by aligning the particle size of the magnetic carrier using the above-mentioned coat resin within a certain range and performing gu+i, it is possible to prevent carrier pull during development and the induction of fireflies, etc., which tend to occur due to the lower resistance of the carrier. Based on. 1 In this specification, carrier attraction refers to the fact that the electrostatic latent material is developed not only by toner but also by carrier, and firefly refers to the fact that toner is randomly spotted on the transfer surface other than the electrostatic latent image. It means to be transcribed.

The conductivity of white toner and chromatic toner is 3-5.
X I Q-1o or below, especially 3. Many have an OX of 10-10 or less. This low conductivity of toner is due to the colorant in the toner. There are many types of colorants in the form of organic pigments that can be used in toners that satisfy the above range of conductivity, but conversely, in toners that fall outside the above range, the selectivity of the colorant is poor, making it difficult to obtain a desired color tone. Therefore, in the present invention, there is no inconvenience when selecting it as a toner raw material, and it is possible to widen and enrich the color tone of the developer.

However, in this way the conductivity is 3.5×1Q-10
Below, especially 3. When a toner of OX 10-'' or less is used in combination with a normal carrier, it becomes difficult to obtain a high-density image due to an increase in the amount of toner charge.

As described above, the magnetic carrier of the present invention uses a specific coating resin to stabilize the toner charge amount within an appropriate range in order to compensate for the difference in charge amount caused by the toner conductivity.

That is, in the magnetic carrier of the present invention, by using arn-containing silicon as the coating resin, the amount of toner charge can be adjusted to an appropriate amount without reducing the amount of coating.

As shown in Figure 2, with conventional magnetic carriers coated with acrylic resin, the amount of coating could be used at most 0.05% or less, whereas with magnetic carriers made of amine-containing silicone resin, the amount of coating could be no more than 0.05%. It is understood that even if the coating amount is increased to .1%, no problem arises in the amount of charge. Therefore, when amine-containing silicon is used as the coating resin for the magnetic carrier as in the present invention, the amount of charge on the magnetic carrier can be reduced and a sufficient protective coating layer can be formed. The reduction in the amount of charge on the magnetic carrier due to the changed use of this resin suppresses the increase in the amount of charge on the toner,
Moreover, it is possible to increase the amount of coating.

Furthermore, the current value of the magnetic carrier is closely related to the carrier material and the amount of resin coating, and the current value of the m-type carrier is 0.
．． It is desirable to adjust it so that it satisfies the range of 1 to 70 μA, especially when using a Se-based photoreceptor.
The range of 5 to 3 μA is good, and if a positively charged organic photoreceptor is used, the range of 30 to 40 μA is good.The image obtained with the 1!14 IA agent combined in this way has a density like a white spot. Excellent high-density images can be obtained without any deterioration. In this specification, the current value refers to the current value when the carrier forms a magnetic brush on the developing sleeve.
It also means the current value when connected to a 200V DC power supply while moving. By the way, what is white nuke?

Particularly in the solid portion of the latent material, it refers to the portion where the carrier adheres to the drum or the like and the toner is not transferred.

In the present invention, the particle size of the carrier is 50% of the weight average particle size.
Adjust the particle size of the carrier so that the % diameter D5゜ satisfies the van of 70 to 120 pm, especially 70 to 90 μm when using a Se-based photoreceptor, and 80 to 120 μm when using a positively charged organic photoreceptor. , it is preferable to carry out in combination with the above-mentioned coating resin.

When the particle size of the carrier is made uniform within the above range, fireflies and carrier attraction are less likely to occur. That is, when the particle size of the magnetic carrier falls below the above range, the relatively small particle size of the carrier causes fireflies, carrier attraction, etc. in combination with a low resistance. On the other hand, if the particle size exceeds the above-mentioned IIRH, the extinction 11Ji of the toner becomes large.

The 50% diameter D50 of the weight average particle size of the carrier particles is defined as the diameter D50 of carriers at which one weight of carriers with a small particle size is sequentially counted and when this amount reaches 50% of the total. It refers to the value of the central particle diameter, and counting can be carried out by passing it through a predetermined mesh sieve.

Further, the developer of the present invention has a bias potential of 250V.

In particular, it can be used at 280V or higher. Increasing the bias potential can reduce or eliminate the influence of the residual potential of the photoreceptor, ie, the residual potential is at least 150V!
Even at one high potential, the photoreceptor can provide excellent image quality without carrier attraction. In this case, the particle size of the carrier is preferably 80 μm to 120 μm.

FIG. 3 is a diagram showing the relationship between the carrier attraction state and the bias potential of the developer using a conventional carrier and the carrier of the present invention. The following carriers are 8% by weight or less. As shown in Figure 3113, in the conventional developer, carrier attraction increases as the bias potential increases. It is understood that this is because the magnetic carrier gradually increases the charge repulsion with the developing sleeve, making it easier for the carrier to transfer to the photoreceptor. However, in the developer of the present invention, by controlling the particle size of the magnetic carrier to satisfy the above range, carrier attraction is significantly suppressed even when the bias potential increases.

In addition, examples of such photoreceptors with a high residual potential include positively charged organic photoreceptors (OPC), which positively charged organic photoreceptors are provided with conditions for suitably using the developer of the present invention. It is something that exists. Further, an increase in the bias potential lowers the development potential difference given by the difference between this potential and the surface potential, and in some cases, low potential development is forced. Such low potential development deteriorates image density. However, the above-mentioned Do-s width is less than 1.2 m, especially 1.0
Under developing conditions below, excellent gradation and W image density are maintained, and carrier attraction does not occur.For this reason, the developer of the present invention can be applied to positively charged organic photoreceptors. It is.

(Preferred Embodiments of the Invention) Preferred embodiments of the developer according to the present invention will be described below.

The developer of the present invention is a two-component developer consisting of a magnetic carrier and a toner, and the magnetic carrier, toner, and developer will be explained in turn.

In the present invention, as the magnetic carrier, it is preferable to use ferrite particles coated with an amine-containing silicone resin as described above, and it is desirable that the particle size distribution is within the range described above.

That is, the amine-containing silicon contains amine, and the content thereof is 0.1 to 10% by weight.
In particular, it is desirable to satisfy 0.1 to 5% by weight of I[N, and do not include those containing only hydrocarbons such as acrylic silicon, or those containing only halogen elements, and the amount of coating on ferrite particles. is 0.01 to 1.
It is desirable that the amount of resin coating satisfies the range of 0%, especially 0.02 to 0.7%.If the resin coating amount is less than this range, rust etc. on the surface of the ferrite particles cannot be sufficiently prevented, and if it is more than the above range. This is undesirable because the amount of charge on the magnetic carrier increases.

As specific amine-containing silicones, alkylamine-based and aromatic winged amine-based silicones are preferred.

In particular, aromatic amines such as benzylamine silicone are preferred.

Specific examples of ferrite include #zinc oxide (
ZnFezOn), Y3Fas
O+z).

Cadmium iron oxide (CdFe, On), gadolinium (GdFe20.2), lead oxide (PdF
es20+*), II-based wheat nickel (NiFe20
t3, neodymium iron oxide (NdFeOs), barium oxide (BaFelzOss), pig iron magnesium MgFe2O4), liI manganese (Mn)
Sintered ferrite particles having a composition consisting of one or more of Fe204), lanthanum II pig iron oxide (LaFeOs), etc. are used.

In particular, soft ferrite containing at least one, preferably two or more metal components selected from the group consisting of Cu, Zn, Hl, Mn, and Ni, such as steel-zinc-magnesium ferrite, can be used.

In the present invention, the resin-coated magnetic carrier particles are preferably spherical from the viewpoint of fluidity, and in the carrier particle group, the diameter is 50% of the weight average median particle diameter. It is important that the value satisfies the aforementioned range. Adjustment of the particle size in such a range can be performed by a method known per se,
The adjustment may be made during sintering of the ferrite, or after the coating resin is applied. Arranging the carrier particles in such a range can prevent problems such as white spots and improve the toner transfer rate, as described above.

Furthermore, if the carrier particles are arranged to have the above-mentioned particle size and the difference between the 25% diameter D25 and the 75% diameter I) ts of the 1 weight average center grain is within the range of 0 to 20 μm, then 1 grain. The diameter distribution becomes even sharper, which will be described later. -5 Even if the width is further shortened from less than 1 m, there will be no carrier pull. *Ta. Carrier attraction is prevented even when the bias potential is high. Furthermore, with a magnetic carrier having such a particle size distribution, an improvement in the per-image density is observed, and the increase in particle size based on the sharpening of the carrier particle size distribution is achieved when the image carrier and developer carrier are in the form of a drum. Reduces torque and drum circumferential friction.

Furthermore, as a material that sufficiently prevents carrier pull, 25
It is desirable to eliminate carriers with a microparticle size of 0 mesh or less1
The amount of carrier with a particle size distribution of 250 mesh or less is 8% by weight.
Below, it is desirable to use a developer that satisfies the range of 5% by weight or less.A developer that satisfies this range sufficiently prevents carrier attraction even in a state where the bias potential is high, and has other effects other than those mentioned above. Reduce fog etc.

The saturation magnetization of the magnetic carrier is 50 to 7 Q emu/z
In particular, those in the range of 55 to 65 u/g have a saturation magnetization lower than that of conventional developer carriers, and this magnetic carrier is more sensitive to magnetic brushes than conventional carriers. Promote the softening of the ears,
Softening the ears reduces drum stress. Especially when the dog width is less than 1.21,
．． The flow wave of the carrier used in the present invention is preferably less than 0 mm, and the flow wave of the carrier is 15 to 35 sec/
50 g, especially one that satisfies the range of 150 g for 20 to 30 seconds.

Toner The toner used in the present invention is a fixing resin medium containing a white or chromatic colorant, a charge control agent, or a well-known toner compound, and has an electrical conductivity of 3.5. X 10-” s/an or less.

Especially 3. OX IQ ” s/m or less, 2.OX
The fixing resin medium, colorant, charge control agent, and other compounding agents for toner may be used in appropriate combinations within the range that has the above characteristics. be done.

As the fixing resin medium, styrene resin, acrylic resin, styrene-acrylic resin, polyester resin, polyurethane resin, silicone resin, polyamide, modified rosin, etc. are used.

Styrene-acrylic copolymer resin is one of the suitable resin media, and the styrene monomer (A) and acrylic monomer (B) have a ratio of A:B=50:50 to 90. :10, especially preferably in the range of 60:40 to 85:15, and the resin used is generally O to 25
In addition, from the viewpoint of fixing properties, it is preferable to have a glass transition temperature (Tg) of 50 to 65°C.

The coloring agent to be contained in the resin is a known coloring agent that has been conventionally used in this field, and those having electrical conductivity within the above range are used.

Coloring agents are broadly classified into white pigments, cyan pigments, magenta pigments, and yellow pigments.Furthermore, these colorants may be contained in a range of 1% to 20% by weight based on the binder resin. desirable.

Next, as specific colorants, for example, as a magenta colorant, C, 1, Pigment Red 81. C, 1, Pigment Red 122,
C,1, Pigment Red 57, C,1, Solvent Red 49. C,1, Solvent Red 19, C,1
,Solvent Red 52,C,1,Basi
c) Red 10, C, 1, Disper
se) Red 15, etc., and cyan colorants include C,1, Pigment Blue 15. C,1,
Pigment Blue 16. C, 1, Solvent Blue 25, C, 1, Solvent Blue 55°C,! , Solvent Blue 0, C, 1, Direct Blue 86.
Examples include C, 1, Direct Blue 25, etc.

Yellow colorants include C.1, Pigment Yellow 17. C, 1, Pigment Yellow 12. C,1,
Pigment Yellow 1, C, 1, Pigment Yellow 9
7°C, 1, Pigment Yellow 138. C,1,
Pigment Yellow 12. c.1. Pigment Yellow 73, C,1, Pigment Yellow 13, C,1, Solvent Yellow 29, C,1, Solvent Yellow 16
Examples include 2゜C1・Work, Solvent Yellow 93, etc.
Examples of the white pigment include zinc titanium oxide, antimony white, and zinc sulfide, particularly titanium oxide.

The charge control agent can then be any charge control agent known per se, such as nigrosine base (CI 50415).

Oil black (CI 26150), oil-soluble dyes such as spirone black, metal-containing azo dyes, naphthenic acid metal salts, alkylsalicylic acid metal salts, fatty acids and soaps,
Resin acid soap etc. are used.

The particle size of the toner particles is 8 to 14 μm on a volume basis, especially 10 μm as measured by a Coulter counter.
It is preferable that the particle size is in the range of 12 μm to 12 μm, and the particle shape may be an amorphous particle produced by a melt mixing/pulverization method, or a spherical particle produced by a dispersion or cloud polymerization method. The surface may be sprinkled with a surface treatment agent known per se such as hydrophobic silica particles or resin powder to improve its fluidity.

Hair Emperor 1 The developer usually contains the above-mentioned magnetic carrier and toner in a ratio of 99:
It is desirable to mix and use them at a weight ratio of 1 to 90:10, particularly 98:2 to 95:5.

In addition, the initial charge amount of the developer is 5 to 25 μc/g, especially 10 to 20 μc/g, as measured by the blow-off method.
It is desirable to satisfy the range of g. The loose apparent specific gravity of the developer is 1.7 to 2.1 (g/c hazy), especially 1
．． Those satisfying the range of 8 to 2.0 (z/cm') are preferred for the purpose of the present invention.

The developer of the present invention is used under the usual developing conditions in this field, but when it is particularly desired to improve the image *a degree, the image carrier-developer carrier distance Do-a is less than 1.2 m. The image carrier and developer carrier of the developing mechanism to be used, which is preferably used under the condition that the developing potential difference is 500 V or less, may be of a flat type or a drum type as shown in FIG.

It is desirable that DD-B satisfies the above range.

Developers under development conditions where the D o-s width is less than 1.2 m, especially less than 1 m, are #thinned even in low potential development.

It can provide excellent color image density,
If the above carrier requirements are taken into account, carrier pull etc. will not occur, and furthermore, depending on the reduction of the Do-a width, the wIL during ear cutting will be 0.5 to 1.5, especially 0.7 to 1.
．． It is desirable to provide it within a range of 2 m.

Further, the developer of the present invention has a development potential difference of 500V, especially 4
Under the condition of 80V or less, if the surface potential of the photoreceptor drum is applied to 750 to 850V, it becomes possible to use a photoreceptor drum or the like to which a bias potential of 250 to 350V is applied. In such a rise in bias potential, the residual potential of the photoreceptor drum is approximately 150V or more,
In particular, it can be used even when the voltage is about 200V.

As the photoreceptor, a photoreceptor used in conventional electrophotography, such as a selenium photoreceptor, an amorphous silicon photoreceptor, a zinc chloride photoreceptor, a cadmium selenide photoreceptor, a cadmium sulfide photoreceptor, etc. is used. However, in the present invention, the developer is a selenium-based photoreceptor and a positively charged organic photoreceptor (OPC).
The positively charged organic photoreceptor, which is preferably used for becomes a trap, and the residual potential tends to increase. Such a photoreceptor has a bias potential of at least 250
The developer of the present invention provides excellent images even at such bias potentials and does not cause carrier attraction.

As a specific positively charged organic photoreceptor, a photoreceptor in which a well-known charge generating material and a charge transporting material are combined can be used, and in particular, the organic photoreceptor proposed earlier in Japanese Patent Application Publication No. 62-27158 can be used. etc. is desirable.

(Effect of the invention) According to the invention, the electrical conductivity is 3.5
s/country or less, especially 2. OX 10-10 to 3-OX
Using color toner that meets the range of 10-”aI countries,
Furthermore, since amine-containing silicone is used for the resin coating of the carrier, a highly turbid image can be provided without causing any defects in the coating of the magnetic carrier.

In addition, in the case of a white developer, contamination of the toner by oxides of the carrier core is prevented, and a clear white image with high whiteness can be provided.

Furthermore, by selecting the particle size of the carrier, it is possible to eliminate inconveniences during development such as white spots and carrier drag, and also to improve l! By changing the image conditions, the present invention can further improve the image density. Moreover,
It can be satisfactorily applied as a developer for organic photoreceptors, which have recently been frequently used, particularly for positively charged type photoreceptors.

(Example) Examples and comparative examples will be shown below, but the present invention is not limited to the scope of the examples.

The components of the developer and the developing conditions were set as follows. The Toe magnetic carrier was a spherical amine-containing silicone coated ferrite carrier and an acrylic polymer, and its physical properties are shown in Table 1.

A toner with known particle size, pigment components, electrical conductivity, etc. was used. Its physical properties are shown in Table 1.

The developer has a weight ratio of toner and carrier of 4.5:95.5.
The basic physical properties are shown in Table 1.

Table 1 shows the developing conditions: width-6 width, cutting width, developing potential difference, bias potential, and photoreceptor.

Table 1 shows the results of development (carrier attraction, image density) using the developer with the above conditions and components.

[Brief explanation of drawings]

FIG. 111 is an explanatory diagram of the developing mechanism section, and FIG. 112 is a diagram showing the relationship between the amount of resin coating and the amount of charge on the carrier. Figure jlI3 is a characteristic diagram showing the relationship between bias potential and carrier attraction.

Claims (7)

[Claims] (1) A color developer comprising a color developing toner having an electrical conductivity of 3.5×10^-^1^0 s/cm or less and a magnetic carrier coated with an amine-containing silicone resin. (2) The conductivity of the toner is 2.0×10^-^1^0
The current value of the magnetic carrier is 0.5 to 5.
2. The developer according to claim 1, wherein the developer is μA. (3) The coating amount of the carrier coated with the amine-containing silicone resin is 0.01 to 0.5% based on the carrier core material. developer. (4) 50% diameter D_5_ of the weight average particle diameter of the carrier
4. The developer according to claim 1, wherein 0 satisfies a range of 70 to 90 μm. (5) 50% diameter D_5_ of the weight average particle diameter of the carrier
0 satisfies the range of 80 to 120 μm, the distance between the image carrier and the developer carrier is less than 1 mm, and the development potential difference is 500 μm.
Claim 1 is characterized in that it is used under the conditions of V or less.
The developer according to items 1 to 3. (6) The developer according to claim 5, wherein the image carrier is a positively charged organic photoreceptor. (7) The developer according to any one of claims 1 to 6, wherein the toner is a white toner containing titanium oxide.