JPH05249742A - Full color toner and picture forming method - Google Patents

Abstract

PURPOSE:To obtain high picture density and durability and a stable fixing characteristic by specifying the distribution of a binder resin to be used for an yellow toner, a magenta toner and a cyan toner and further specifying the FeO content of a black toner. CONSTITUTION:The yellow toner, magenta toner and cyan toner are a nonmagnetic toner consisting of a colorant, a binder resin and an additive, and the black toner is a magnetic toner having the resin grain with the FeO content in the magnetic iron oxide controlled to 25-30% and an additive. The additive contains at least a flowability improving agent and globular fine grains having 0.2-2.5mum average diameter. The THF-soluble component of the binder resin is allowed to have a peak in the 1,000-100,000mol.wt. region in the mol.wt. distribution by gel permeation chromatography(GPC). However, the binder resin in the black toner has a peak or shoulder in the 2,000-15,000 mol.wt. region and in the 15,000-100,000mol.wt. region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry developer for electrophotography, and more particularly to a full color copying machine using a two-component developing method using a non-magnetic toner and a carrier and a one-component developing method using a magnetic toner. And the full-color toner capable of suitably embodying the image forming method.

[0002]

2. Description of the Related Art In recent years, many image forming apparatuses such as electrophotographic full-color copying machines or printers have been manufactured. Usually, such an image forming apparatus forms a latent image on a latent image carrier by a normal electrophotographic process, develops the latent image with toner to form a toner image, and uses the image as a transfer material. A visible image is obtained by transfer.

At this time, the residual image on the image bearing member is cleaned by a cleaning means, and the image bearing member is repeatedly used, and is made of a rubber elastic material because it is very advantageous especially in terms of downsizing and cost. A blade cleaning means having a structure in which a cleaning blade is pressed against the image carrier in the counter direction is widely used.

Generally, a large number of developing methods are known in such an electrophotographic method. In these developing methods, a magnetic brush using a developer mainly containing toner and carrier is used. Method, cascade method, liquid developing method and the like have been widely put into practical use. All of these methods are excellent methods in which a good image can be obtained relatively stably, but on the other hand, they have the common drawbacks associated with two-component developers such as carrier deterioration and toner / carrier mixing ratio fluctuation.

In order to avoid such drawbacks, various developing methods using a one-component type developer consisting of only toner have been proposed. Among them, many methods are excellent in the method of using a developer comprising magnetic toner particles. .. Among the materials used for the magnetic toner, the magnetic material particularly contains 20 to 70% by weight based on the total weight of the toner, so that the performance of the toner is greatly affected. For example, as disclosed in JP-A-58-189646, a magnetic toner containing a magnetic powder having a FeO content of 16 to 25% by weight can surely obtain a high developing efficiency of an electrostatic image and a good transferring efficiency. It is shown. However, as a recent tendency, copying machines are advancing toward higher speeds, so that the above-mentioned magnetic toner containing magnetic powder having an FeO content of 16 to 25% by weight should sufficiently satisfy high resolution and high durability. I can't. Further, when a full-color image or the like is obtained by a multi-color developing method, it is difficult to control the delicate color tone of black, which becomes a cause of hindering a clear tint.

On the other hand, in recent years, as a new user needs in the market due to the widespread use of full-color copying machines, full-color copying machines, printers and the like are required to have a dual-purpose function. In other words, in the office environment, there is a demand for a copying machine which can maintain the same speed and quality as a general black-and-white machine and still obtain a clear, high-quality full-color image. In such a case, the number of times the black toner is used alone is increased and the toner consumption is inevitably increased. Therefore, it is desired that the black toner in the full-color copying machine, which is required in the future, has excellent image quality and durability stability. It will be rare.

When an image is formed by combining a plurality of developers having different surface properties such as a magnetic toner and a non-magnetic toner, magnetic toner particles made of a magnetic material and a binder resin, a colorant, a binder, and a binder. Under the present circumstances, it is difficult to always maintain the pressure-bonded state between the photoconductor and the cleaning blade in a stable manner because there is a difference in the sliding property or the scraping property of the non-magnetic toner particles made of the resin to the photoconductor.

In using a magnetic toner and a non-magnetic toner together in the developing process in such a full-color machine, a binder resin that should be optimized for each toner is required. In other words, in the magnetic toner, the dispersion state of the magnetic powder in the binder resin is regarded as a problem, while in the non-magnetic toner, the dispersion of the colored dye / pigment in the binder resin and the improvement of the light transmission property are improved. Is a problem. In addition, the fact that both toners have excellent fixability can be cited as an essential factor in such a case.

For this reason, in electrophotography, regardless of whether it is magnetic or non-magnetic, the toner performance is largely due to the role of the binder resin, such as a releasing agent, a plasticizer, and other additives. Therefore, there is a proposal to improve such a problem, but these are only auxiliary effects and cannot be an essential solution.

Various other methods have been proposed for improving these binder resins.

For example, Japanese Patent Application Laid-Open No. 56-158340 proposes a toner comprising a low molecular weight polymer and a high molecular weight polymer, but this binder resin may actually contain a crosslinking component. Since it is difficult, it is necessary to increase the molecular weight or increase the ratio of the high molecular weight polymer in order to improve the offset resistance with higher performance. This direction is a direction in which the pulverizability is remarkably reduced, and it is difficult to obtain what is practically satisfactory. Further, a toner prepared by blending a low molecular weight polymer and a crosslinked polymer is disclosed in Japanese Patent Application Laid-Open No.
JP-A-8-86558 proposes a toner containing a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components. According to the method, the fixing property and the pulverizing property are thought to be improved, but the insoluble and infusible high molecular weight polymer is 40
Since it is as large as 90% by weight, it is difficult to satisfy both the offset resistance and the pulverizability with high performance. In practice, if the fixing machine does not have a liquid supply device for offset prevention, the fixing property and the offset resistance are high. However, it is extremely difficult to produce a toner that sufficiently satisfies the pulverizability. Furthermore, if the insoluble and infusible high molecular weight polymer is increased, the melt viscosity becomes extremely high in the heat kneading at the time of toner production, so that the heat kneading should be performed at a temperature much higher than usual, or the heat kneading should be performed in a high share. However, as a result, the former has a problem that the toner properties are deteriorated due to thermal decomposition of other additives, and the latter has a problem that the initial offset resistance performance is difficult to be obtained due to excessive cutting between the molecules of the binder resin. .. Further, when the magnetic powder or the dye / pigment is contained in the binder resin, a good dispersed state cannot be obtained.

Further, Japanese Patent Laid-Open No. 56-16144 discloses that
In the molecular weight distribution by GPC, the molecular weight is 10 ³ to 8 × 1
There is proposed a toner containing a binder resin component, at least one of which has a maximum value in each region of 0 ⁴ and a molecular weight of 10 ⁵ to 2 × 10 ⁶ . In this case, the crushability, offset resistance, fixing property, filming and fusing to the photoconductor, image quality, etc. are excellent, but further improvement in offset resistance and fixing property in the toner is demanded. In particular, it is difficult for the resin to meet today's demanding requirements while further improving the fixability and maintaining or improving various other performances.

A binder resin that solves such a problem is disclosed in Japanese Patent Laid-Open No. SHO 63-223014. However, at present, it is sufficient to have further high durability and high reliability. I can't handle it.

Further, the binder resin has a great influence on the developability, and a binder resin having a stable triboelectric charge amount is desired.

Further, in such a system in which magnetic toner and non-magnetic toner are mixed in a plurality on the same image, there arises a problem that surface smoothness is different between fixed images of magnetic toner and non-magnetic toner. There are 20 to 7 magnetic powders in the magnetic toner.
The toner is mixed in a proportion of 0% by weight, and the image surface after fixing is apparently in a rough state, whereas the non-magnetic toner containing the dye / pigment is in a completely melted state and the magnetic toner is in a completely melted state. The surface smoothness is better than that. From such a result, the reflection angle of light showing gloss that is visually appealing to humans is different, and non-magnetic toner has high gloss, whereas magnetic toner has low gloss, and therefore multi-color development is not possible. However, when obtaining a pictorial image, the texture of the obtained image changes.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a full color toner and an image forming method using the toner, which solves the above problems.

That is, it is an object of the present invention to provide a full-color toner using four color toners, which has stable color reproducibility, high image density and high durability.

A further object is to provide a full-color toner which has a stable cleaning property when a magnetic toner and a non-magnetic toner are used together.

A further object is to provide a full-color toner which is excellent in fixing property and at the same time excellent in offset property, winding property and blocking property.

[0020]

Means and Actions for Solving the Problems The present inventors have
As a result of many research experiments, TH of binder resin used in magnetic and non-magnetic toner used in full-color copying machines
It has been found that by defining the molecular weight distribution of the F-soluble component by gel permeation chromatography (GPC), a full-color toner that achieves high image density and high durability and has a clear tint can be obtained.

Further, in the multiple development using the full color toner, the magnetic black toner is developed on the first layer on the latent image carrier, and the non-magnetic color toner is developed on the second layer and thereafter, which is excellent. We have found that an image with different texture can be obtained.

A feature of the present invention is a full-color electrophotographic full-color toner having at least a yellow toner, a magenta toner, a cyan toner and a black toner, wherein the yellow toner, the magenta toner and the cyan toner are colorants,
A non-magnetic toner comprising a binder resin and two or more kinds of external additives, wherein the black toner comprises black magnetic powder-containing resin particles having a FeO content of 25 to 30% by weight in magnetic iron oxide, and two or more kinds of A magnetic toner having an external additive, wherein the external additive contains at least a fluidity improver and a weight average particle diameter of 0.2 to 2.5 μm.
In addition, the binder resin used in the yellow toner, the magenta toner, and the cyan toner has a molecular weight distribution by gel permeation chromatography (GPC) of THF-soluble content.
The binder resin used in the black toner has at least one peak in the molecular weight range of 1000 to 100,000, and the binder resin used in the black toner has a molecular weight distribution measured by gel permeation chromatography (GPC) of a THF-soluble component.
It has at least one peak in the molecular weight range of 2000 to 15,000 and at least one peak or shoulder in the molecular weight range of 15,000 to 100,000.

The magnetic iron oxide having a FeO content of 25 to 30% by weight used in the black toner of the present invention has a high degree of blackness as a black pigment and maintains an appropriate electric resistance, thus stabilizing the toner charge amount. It has an effect of improving the image density, and has a function of improving the rank of fogging on the image in terms of developability.

When a magnetic iron oxide having a FeO content of less than 25% by weight is used for the toner, it becomes difficult to control the toner charge amount properly in a low temperature and low humidity environment, especially when considering application to a high speed machine. However, it is not possible to sufficiently cope with the image density decrease and the background stain due to the excessive increase of the toner charge amount, and it is difficult to control the color tone for obtaining a clear color tone as the black toner.

On the other hand, when magnetic iron oxide having a FeO content of more than 30% by weight is used for the toner, the charge amount of the toner is reduced, especially in a high humidity environment, and the image density is reduced.

This magnetic substance has an average particle size of 0.1 to 2 μm,
It is preferably about 0.1 to 0.5 μm,
The amount contained in the toner is about 20 to 200 parts by weight, preferably 10 parts by weight with respect to 100 parts by weight of the resin component.
40 to 150 parts by weight is preferable to 0 parts by weight.

The magnetic iron oxide used in the present invention is iron sulfate (F
eSO ₄ ) is neutralized with caustic soda (NaOH) and Fe (O
H) ₂ is obtained, and the pH is adjusted to 12 to 13 by adjusting the alkali, and then oxidized by steam and air to obtain a magnetite slurry. In the next drying process, the hot air dryer is used to control the drying temperature and the drying time, so that the FeO in the magnetic iron oxide is
Can be controlled. After the completion of drying, it is crushed to obtain magnetite powder.

Here, the measurement of FeO in magnetic iron oxide is carried out by the following procedure.

1.000 g of magnetic iron oxide was placed in a 500 ml beaker, 50 ml of deionized water was added, and 20 ml of special grade sulfuric acid was added to completely dissolve the magnetic iron oxide.

Next, 100 ml of deionized water was added, and Mn was further added.
SO ₄ , H ₂ SO ₄ and H ₃ PO ₄ (molar ratio 0.3:
2.0: 2.0) MnSO ₄ mixed solution (10 ml) was added to make a total of 180 ml, and 10 ml was sampled.
Titrate with 1N KMnO ₄ solution.

Then, according to the following formula, 1.000 g of magnetic iron oxide
FeO (%) contained therein is determined.

[0032]

[Equation 1] The spherical fine particles that can be used in the present invention include 0.2 to 2.
Anything having a weight average diameter of 5 μm may be used. Further, the starting material, manufacturing method, etc. are not limited.

If the particle size of the spherical fine particles is less than 0.2 μm, the cleaning blade cannot follow the surface of the photoconductor when the surface roughness of the photoconductor is rough, so that the cleaning blade often slips through the cleaning blade, resulting in uneven charging during latent image formation. Occurs,
Image deterioration is likely to occur. On the other hand, if it is larger than 2.5 μm, it is sufficiently cleaned by the cleaning blade, and it is difficult for the cleaning blade to collect on the edge portion of the blade, the spacer function deteriorates, and the efficiency deteriorates.

The spherical fine particles that can be used in the present invention include:
Inorganic oxides such as silicic acid fine powder, alumina fine powder, titanium oxide fine powder, zirconium oxide fine powder, magnesium oxide fine powder, boron nitride fine powder, aluminum nitride fine powder, carbon nitride fine powder, etc. and so on.
In addition, inorganic resin particles such as silicone resin particles can be used.

Silicone resin particles having a siloxane structure having one alkyl group in a silicon atom are particularly preferred for the present invention because the particle size distribution can be sharpened easily. Further, as the particle size distribution, 80% or more in the volume distribution is preferably within ± 30% of the average particle size. Moreover, you may perform surface treatment as needed. The amount of addition is 0.05 to 3% by weight, preferably 0.1 to 2% by weight.

The particle size distribution of the spherical fine particles of the present invention was measured with a particle analyzer (CAPA500).

In the present invention, in addition to the spherical fine particles, it is necessary to include a flow improver as an external additive. Examples of such a fluidity improver include silica, alumina, titanium oxide and the like, and BET is used in terms of imparting fluidity.
The specific surface area is preferably 50 m ² / g or more.

Further, if necessary, a fatty acid metal salt as a lubricant, such as zinc stearate or aluminum stearate, or a fine powder of a fluorine-containing polymer, such as polytetrafluoroethylene, polyvinylidene fluoride or the like and tetrafluoroethylene- Fine powder of vinylidene fluoride copolymer or a conductivity-imparting agent such as tin oxide or zinc oxide may be added.

The binder resin used in the yellow toner, the magenta toner and the cyan toner in the present invention has a molecular weight distribution of 1000 to 100 in terms of the molecular weight distribution by THF permeation chromatography (GPC).
It is desirable to have at least one peak in the 100,000 region. When the peak deviates from the above range, not only the blocking property is impaired, but also the fixing property in a wide temperature range is not obtained, and when multiple development is performed as a result, the clear color reproducibility required for full color is obtained. That is, the mixed color area cannot be obtained.

On the other hand, the binder resin used for the black toner has at least one peak in the molecular weight range of 2000 to 15000 in the molecular weight distribution by gel permeation chromatography (GPC) of the THF soluble component. It is desirable to have at least one peak or shoulder in the molecular weight range of 15,000 to 100,000. 20
If there is no peak at 00 to 15000 and there is a peak at a molecular weight of less than 2000, blocking resistance, fusing to the photoreceptor, filming, fusing to the inner wall of the crushing device, etc. become somewhat problematic. If there is no peak at a molecular weight of less than 15,000 and there is a peak at a molecular weight of 15,000 or more, pulverizability may be a problem, and formation of coarse particles may be a problem.

Further, when there is no peak in the region where the molecular weight is 15,000 or more, or there is no shoulder, and there is only a peak in the region where the molecular weight is less than 15,000, offset resistance and fusion of the photoreceptor may become problems. Molecular weight 15,000-100
There are no peaks or shoulders in the area of 10,000 and 10,000
If there is a main peak in a region exceeding 0, pulverizability may become a problem.

More preferably, the molecular weight is 2000 to 150.
Peaks in the region of less than 00 and molecular weight of 15,000 to 10
The peak or the gap between the peak and the shoulder in the region of 10,000 has a difference of 5,000 or more, preferably 10,000 or more.

Further, such a molecular weight distribution is within the range according to the present invention in order to enhance the dispersibility of the black magnetic powder in the binder resin at the time of toner production and to obtain high coloring power and stable charging characteristics. This is because it becomes possible.

The THF-insoluble matter in the present invention means a weight ratio of a polymer component (substantially a crosslinked polymer) which becomes insoluble in THF in the resin composition, and indicates the crosslinking of the resin composition containing the crosslinking component. Can be used as a parameter indicating the degree of. The THF-insoluble matter is defined as a value measured as follows.

That is, 0.5 to 1.0 g of a resin sample (24 mesh pass, 60 mesh on powder) is weighed (W ₁ g), and a cylindrical filter paper (for example, No. 8 manufactured by Toyo Roshi Kaisha, Ltd.).
6R) and applied to a Soxhlet extractor, and extracted with 100 to 200 ml of THF as a solvent for 6 hours, and the soluble component extracted with the solvent was evaporated, and then 1
After vacuum drying at 00 ° C. for several hours, the amount of the THF-soluble resin component is weighed (W ₂ g). The THF insoluble content of the resin is calculated from the following formula.

[0046]

[Equation 2] The evaporated dry matter of the solvent-soluble component obtained by the above operation is TH
It is dissolved in F (tetrahydrofuran), passed through a sample processing filter, and used as a GPC sample.

In the present invention, the molecular weight of the peak or / and shoulder of the chromatogram by GPC (gel permeation chromatography) of the THF-soluble matter is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) as a solvent was flowed through the column at this temperature at a flow rate of 1 ml / min to obtain a sample concentration of 0.05 to 0.6 wt. The measurement is performed by injecting 50 to 200 μl of the THF sample solution of the resin adjusted to 100%. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value and the count number of a calibration curve prepared using several kinds of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical
Co. Made or manufactured by Toyo Soda Kogyo Co., Ltd. has a molecular weight of 6
× 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 1
0 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10
^It is suitable to use ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ standard polystyrene samples of at least about 10 points. Also, the detector is RI
A (refractive index) detector is used.

As a column, 10 ³ to 2 × 10
^In order to accurately measure the molecular weight region of ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns.
Atters μ-style 1500, 10
Combination of ³ , 10 ⁴ , 10 ⁵ and sh from Showa Denko
odex KF-80M and KF-801, 803, 8
04,805 combination, KA-802,803,8
04,805 combination or TS made by Toyo Soda
Kge1 G1000H, G2000H, G2500
H, G3000H, G4000H, G5000H, G6
A combination of 000H, G7000H and GMH is preferable.

In the multicolor developing method of sequentially forming an image on the latent image carrier using these full color toners, in the present invention, the black toner is developed on the latent image carrier in the first order,
From the second order onward, cyan toner, yellow toner,
It is desirable to develop magenta toner to control multiple image formation. In the case of the black-and-white dual-purpose copying machine according to the present invention, there are many opportunities to obtain continuous black and black copy images, and if so-called coalescence among particles is performed, the fixing characteristic has two peaks. It is desirable to use a relatively hard binder resin as a medium. However, when copying a pictorial image such as a full-color image, a clear tint is required, and inevitably a binder resin that is relatively easy to melt is desired in order to facilitate color mixing.

In the above cases, in order to satisfy both, the influence of the surface glossiness due to the difference in the binder resin as shown in FIG.

Therefore, when the magenta toner is developed in the first order, and the cyan toner, the yellow toner, and the black toner are sequentially developed in the conventional multicolor development, the full-color toner of the present invention is used. When transferring sequentially onto copy paper such as paper after development, the black toner containing the magnetic substance comes to the uppermost layer, which hinders the glossiness of the three colors below it, resulting in four-color overlapping. In addition, in a full-color image, different glossiness is generated in various parts of the image area. From the above, in the present invention, a multi-color image is obtained in an appropriate development order to form a black toner having low glossiness on the lowermost layer on the transfer paper to prevent irregular reflection of light and to obtain a uniform image. It is possible to obtain a full-color image having gloss.

Colorants suitable for the purposes of the present invention include the following pigments or dyes. In the present invention, C.I. I. Disperse Y164, C.I. I. Solvent Y77 and C.I. I. Colorants such as Solvent Y93 are not recommended.

Examples of the dye include C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I.
Mordant Red 30, C.I. I. Direct Blue 1,
C. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modant Blue 7 etc.

Examples of pigments include Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet. There are rake, phthalocyanine blue, fast sky blue, indanthrene blue BC and the like.

Disazo yellow, insoluble azo and copper phthalocyanine are suitable as pigments, and basic dyes and oil-soluble dyes are suitable as dyes.

Particularly preferably, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 1
4, C.I. I. Pigment Yellow 12, C.I. I. Pigment Red 5, C.I. I. Pigment Red 3, C.I. I.
Pigment Red 2, C.I. I. Pigment Red 6,
C. I. Pigment Red 7, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 16 or a copper phthalocyanine pigment having the structural formula (I) shown below, in which the phthalocyanine skeleton is substituted with 2 to 3 substituents.

[0058]

[Chemical 1] As the dye, C.I. I. Solvent Red 49, C.I. I.
Solvent Red 52, C.I. I. Solvent Red 10
9, C.I. I. Basic Red 12, C.I. I. Basic Red 1, C.I. I. For example, Basic Red 3b.

Regarding the content of yellow toner, which is sensitive to the transparency of the OHP film,
12 parts by weight or less based on 100 parts by weight of the binder resin,
Preferably 0.5 to 7 parts by weight is desirable.

When it exceeds 12 parts by weight, the reproducibility of green and red, which are mixed colors of yellow, and human skin color as an image is poor.

For the other magenta and cyan color toners, the amount is preferably 15 parts by weight or less, more preferably 0.1 to 9 parts by weight or less with respect to 100 parts by weight of the binder resin.

As the latent image carrier in the present invention, an organic photoconductor containing 5 to 40% by weight of a fluororesin powder on its surface is suitable. As a result of diligent studies on the cleaning property and the image property when both the magnetic toner and the non-magnetic toner are applied, the present inventors have found that as an external additive of the toner, spherical particles having a weight average particle diameter of at least 0.2 to 2.5 μm are used. It has been found that the toner containing the fine particles stabilizes the cleaning property in various environments regardless of the presence or absence of the magnetic substance, and provides a good image.

The reason why the cleaning property is stable is as follows.
This is because the excessive spherical pressure between the surface of the organic photoconductor and the cleaning blade is mitigated by the spherical fine particles serving as spacers, and appropriate friction characteristics can be obtained.

The toner according to the present invention may be blended with a charge control agent in order to stabilize the charging characteristics. At that time, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferable. In the present invention, when a negatively chargeable developer is used, the present invention becomes more effective, and examples of the negatively charge control agent in that case include metal complexes of alkyl-substituted salicylic acid (for example, chromium of di-tert-butylsalicylic acid). Complex or zinc complex). When compounding the negative charge control agent with the toner, the binder resin 100 is used.
0.1 to 10 parts by weight, preferably 0.5
It is recommended to add ~ 8 parts by weight.

The magnetic particles used in the two-component developer of yellow, magenta, and cyan in the full-color developer of the present invention include, for example, surface-oxidized or unoxidized iron, nickel, copper, zinc, cobalt, manganese, and chromium. Metals such as rare earths and their alloys or oxides and ferrites can be used. In addition, there is no particular limitation on the manufacturing method.

The most suitable material for the magnetic particles used in the present invention is a composition of Cu-Zn-Fe (composition ratio (5-20) :( 5-20) :( 30-80)) of 98% or more. Ferrite particles, which are easy in surface smoothing, stable in charge imparting ability, and stable in coating.

In the present invention, the surface of the above-mentioned magnetic particles is coated with a resin or the like. As a method thereof, a coating material such as a resin is dissolved or suspended in a solvent and applied to adhere to the magnetic particles, Any conventionally known method such as a method of simply mixing with powder can be applied. In order to stabilize the coating layer, it is preferable that the coating material be dissolved in a solvent.

The material for coating the surface of the magnetic particles varies depending on the toner material, but is preferably, for example, an amino acrylate resin, an acrylic resin, or a copolymer of these resins and a styrene resin. As the negatively charged resin, silicone resin, polyester resin, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride and the like are preferable because they are located on the negative side in the charging series, but are not necessarily limited thereto. ..

The most suitable for the present invention is an acrylic resin or a copolymer of these resins and a styrene resin.

The coating amount of the above compound may be appropriately determined so that the charge imparting property of the magnetic particles satisfies the above-mentioned conditions, but generally, the total amount is 0.1 to 30% by weight based on the magnetic particles.
(Preferably 0.3 to 20% by weight).

The weight average particle diameter of these magnetic particles is 35 to 6
It is preferable to have 5 μm, preferably 40 to 60 μm. Further, the weight distribution of 26 μm or less is 2 to 6%, and the weight distribution of 35 μm to 43 μm is 5% or more 25
%, And when 74 μm or more and 2% or less, a good image can be maintained.

In the present invention, the mixing ratio of the above magnetic particles and toner particles is 2.0 as the toner concentration in the developer.
Good results are usually obtained with weight percentages of 9% by weight, preferably 3% by weight to 8% by weight. Toner concentration is 2.0%
If it is less than 9%, the image density is too low to be practically applicable, and if it is more than 9%, the fog and the scattering in the machine are increased and the useful life of the developer is shortened.

To prepare the colorant-containing resin particles according to the present invention, a thermoplastic resin, if necessary, a pigment or dye as a colorant, a charge control agent, other additives and the like are sufficiently mixed with a mixer such as a ball mill. After mixing, a heat roll, a kneader, an extruder is used to melt, knead and knead using a heat kneader such as an extruder to disperse or dissolve the pigment or dye in the resin to make them compatible with each other, and after cooling and solidifying. The colorant-containing resin particles according to the present invention can be obtained by pulverization and strict classification.

As the binder used in the present invention, various material resins conventionally known as electrophotographic toner binder resins are used.

For example, polystyrene, styrene-based copolymers such as styrene-butadiene copolymer, styrene-acrylic copolymer, etc., ethylene-based such as polyethylene, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer. Examples thereof include copolymers, phenolic resins, epoxy resins, acrylic phthalate resins, polyamide resins, polyester resins, maleic acid resins and the like. In addition, the manufacturing method and the like of each resin is not particularly limited.

[0076]

EXAMPLES Examples of the present invention will be given below, but all "parts" and "%" are "parts by weight" and "% by weight".

Example 1 Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid (The molecular weight distribution of THF-soluble component in this resin had a peak at 6300.) C.I. I. Pigment Yellow 17 3.5 parts Di-tert-butylsalicylic acid chromium complex salt 4 parts After sufficiently premixing with a Henschel mixer,
The mixture was melt-kneaded with a twin-screw extruder, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 1 to 2 mm. Then, it was pulverized by an air jet pulverizer. Further, the obtained finely pulverized product was classified by a multi-division classifier to obtain yellow resin particles having a weight average particle diameter of 8.0 μm.

With respect to 100 parts of the yellow resin particles, 0.7 part of hydrophilic titanium oxide (BET 70 m ^{2 /} g) synthesized from titanium chloride and an average particle size of 0.8 μm were used.
0.5 parts of spherical silicone resin particles of No. 3 were combined to obtain a yellow toner.

Next, C. I. Pigment Yellow 17 was replaced with 4 parts of rhodamine-based pigment in the same manner as the yellow toner to obtain a magenta toner.

Next, C. I. Pigment Yellow 17 was replaced with 5 parts of a phthalocyanine pigment represented by the following structural formula to prepare a cyan toner in the same manner as the yellow toner.

[0081]

[Chemical 2] Then C. I. Pigment Yellow 17 instead of FeO
Using 60 parts of magnetite having a content of 26.1%, a specific surface area of 8.1 m ² / g and a bulk density of 0.44 g / cm ³ , the following resin A is used as a binder resin, and hexamethyldisilazane is used as an additive to make it hydrophobic. Treated silica fine powder (BET230
A black magnetic toner was prepared by using 0.5 part of m ^{2 /} g) and 0.5 part of spherical silicone resin particles.

The above yellow, magenta and cyan toners were replaced with methyl methacrylate-butyl acrylate (75: 2).
5) A Cu-Zn-Fe ferrite particle surface-coated with a copolymer was mixed with each other so that the toner concentration was 5% to obtain a developer.

Commercially available color copying machine (CLC-500 made by Canon) using the above three kinds of developers and black magnetic toner.
Is modified so that images can be output in the order of black, cyan, yellow, and magenta, and the development contrast is set to 3
The image output was evaluated at a constant voltage of 50V. Even after a 10,000-sheet durability test, there was a clear tint, the image quality did not change significantly, background fog was not seen, and the image density was 1.4 for each color.
It showed a high density of up to 1.5, and no cleaning failure was observed after the durability test.

<Binder Resin A> A copolymer (a) using the following monomer composition was prepared.

Styrene monomer 75.5 parts Butyl acrylate monomer 13.5 parts Monobutyl maleate monomer 10.0 parts Di-tert-butyl peroxide 6.0 parts Next, the following containing the copolymer (a): A mixed solution was prepared.

Copolymer (a) 30.0 parts Styrene monomer 46.0 parts Butyl acrylate monomer 21.0 parts Monobutyl maleate monomer 3.0 parts Divinylbenzene 0.3 parts Benzoyl peroxide 1.0 parts tert- Butylperoxy-2 ethylhexanoate 0.6 part To the above mixed solution, 170 parts of water in which 0.12 part of polyvinyl alcohol partially saponified is dissolved is added, and a homomixer is used so that the emulsion particle size becomes 100 μm or less. It was emulsified to obtain a suspension dispersion. The above dispersion liquid was added to a reactor in which 50 parts of water was charged and the atmosphere was replaced with nitrogen, and a suspension polymerization reaction was carried out at a reaction temperature of 70 to 95 ° C. for 6 hours. After completion of the reaction, filtration, dehydration,
Binder resin composition A was obtained by drying. The molecular weight distribution of the THF soluble component in this resin A is 7,200 and 4
Each had a peak at 6,000.

Shode is used as a GPC measurement column.
x KF-80M was installed in a 40 ° C. heat chamber of a GPC measuring device (150 CALC / GPC manufactured by Waters Co., Ltd.) and a THF flow rate was 1 ml / min. .1%)
GPC was measured by injecting 200 μl of As a calibration curve for molecular weight measurement, the molecular weight is 0.5 × 10 ³ , 2.35.
X10 ³ , 10.2 x 10 ³ , 35 x 10 ³ , 110 x
10 ³ , 200 x 10 ³ , 470 x 10 ³ , 1200 x
A THF solution of 10 ³ , 2700 × 10 ³ , and 8420 × 10 ³ monodisperse polystyrene standard substances (manufactured by Waters) was used.

Example 2 In Example 1, the magnetite in the magnetic toner was FeO.
Image formation was performed in the same manner as in Example 1 except that the content was 28.1%, the specific surface area was 7.4 m ² / g, and the bulk density was 0.46 g / cm ³ , and the black image density was 1.6 to The same good result as in Example 1 was obtained except that it was as high as 1.7.

Example 3 In Example 2, the hydrophilic titanium oxide contained in each of the yellow, magenta and cyan toners was a hydrophilic titanium oxide synthesized from titanium isopropoxide (BET12).
0 m ² / g) was used in the same manner as described above except that 0.5 part was used. As a result, a clear color tone was obtained, the image density was high, and good cleaning results were obtained. It was

Example 4 In Example 1, the magnetite in the magnetic toner was Fe.
O content is 27.2%, specific surface area is 7.6 m ² / g, bulk density is 0.42 g / cm ³ , and 0.5 part of titanium oxide obtained by hydrophobizing hydrophilic titanium oxide with dimethyl silicone oil is used. Images were printed in the same manner as in Example 1 except for the above, and the image density was stable, and the image quality did not change significantly even after a durability test of 10,000 sheets, and no problems such as fog were observed.

Comparative Example 1 The same evaluation as in Example 1 was conducted except that the binder resin used in the black magnetic toner was the binder resin shown in the following B.

<Binder Resin B> Styrene monomer 72.0 parts Butyl acrylate monomer 24.0 parts Monobutyl maleate monomer 4.0 parts Divinylbenzene 0.30 parts Benzoyl peroxide 1.7 parts Polyvinyl alcohol is added to the above mixture. Partially saponified product 0.
170 parts of water in which 12 parts were dissolved was added to obtain a suspension dispersion liquid which was sufficiently emulsified. 50 parts of water was added, the above dispersion liquid was added to a reactor purged with nitrogen, and the reaction was carried out at a reaction temperature of 70 to 95 ° C for 6 hours. After the reaction was completed, the resin was separated by filtration, dehydrated and dried to obtain a binder resin B.

When the molecular weight distribution of the THF soluble component in this resin B was measured, it had a peak in the region of molecular weight 24,000.

When a durability test was carried out, no fog or the like was observed, but there were many coarse particles in the toner, which adhered to the photoconductor during development and caused fusion due to factors such as rubbing. It was

Comparative Example 2 Evaluation was made in the same manner as in Example 1 except that the binder resin used for the yellow toner, magenta toner and cyan toner was the resin C described below.

<Binder Resin C> Polyester Resin C Obtained by Condensing Ethoxylated Bisphenol A and Terephthalic Acid This resin C has a peak in the region of 120,000 as the molecular weight distribution of the THF-soluble component. there were.

When an initial evaluation was performed, an offset was observed in the cyan toner using the resin C, and the other two colors were not sufficiently melt-fixed at the time of fixing, so that the obtained multicolor image was also obtained. Inadequate color mixing caused a problem in the tint, resulting in a marked deterioration in image quality.

Comparative Example 3 Instead of the magnetite used for the black toner in Example 1, the FeO content was 23.0%, the specific surface area was 7.7 m ² / g,
The same evaluation as in Example 1 was performed except that magnetite having a bulk density of 0.29 g / cm ³ was used.

In the durability test, the image quality did not change significantly, and fog and the like were not observed, but the image density decreased from around 2000 sheets.

Comparative Example 4 The same evaluation as in Example 1 was carried out except that the toner was constituted by removing hydrophilic titanium oxide as a flow improver and fine powder of silicic acid using the color toner and the black toner in Comparative Example 4. As a result, image unevenness occurred in the halftone portion under the environment of 20 ° C./10%.

Comparative Example 5 In Example 1, the same evaluation as in Example 1 was carried out except that the color toner and the black toner did not contain spherical fine particles, but a high image density could be maintained, but on the image Since a large number of cleaning failure marks were generated, the evaluation was interrupted during the endurance test of 1000 sheets.

[0102]

According to the present invention, a full-color toner having a stable fixing property can be obtained by defining the distribution of the binder resin component of the toner used in a black-and-white machine dual-color full-color copying machine and printer. In addition, by defining the FeO content in the magnetic powder used in the black toner, it becomes possible to maintain high image density and high durability, and also as a external additive, a fluidity improver and spherical fine particles. By containing the above, it has become possible to improve the cleaning characteristics in the combined system of non-magnetic and magnetic toner.

[Brief description of drawings]

FIG. 1 is a graph showing the influence of surface glossiness due to the difference in binder resin.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 9/08 15/01 J G03G 9/08 321 372 375

Claims (5)

[Claims] 1. A full-color electrophotographic full-color toner having at least a yellow toner, a magenta toner, a cyan toner, and a black toner, wherein (1) the yellow toner, the magenta toner, and the cyan toner are a colorant, a binder resin, and A non-magnetic toner containing two or more external additives,
(2) The black toner is composed of a magnetic toner containing black magnetic powder having a FeO content of 25 to 30% by weight in magnetic iron oxide, a binder resin, and two or more external additives, (3) In addition, the binder resin used for the yellow toner, the magenta toner, and the cyan toner has a peak in at least a molecular weight range of 1000 to 100,000 in the molecular weight distribution by gel permeation chromatography (GPC) of the THF soluble content. (4) The binder resin used for the black toner has at least one peak in the molecular weight range of 2000 to 15000 in the molecular weight distribution by THF permeation gel permeation chromatography (GPC). And a full-color toner having at least one peak or shoulder in the molecular weight range of 15,000 to 100,000. . 2. The full-color toner according to claim 1, wherein the external additive contains at least a fluidity improver and spherical fine particles having a weight average particle diameter of 0.2 to 2.5 μm. 3. The full-color toner according to claim 2, wherein the spherical fine particles are silicon-containing compounds such as silicic acid fine powder and silicone resin particles. 4. The full color toner according to claim 2, wherein the spherical fine particles are silicone resin particles having a siloxane structure having one alkyl group in a silicon atom. 5. A multicolor developing method for forming a toner image on a latent image carrier on a transfer material in sequence by using the full-color toner according to claim 1, wherein the black toner is transferred onto the transfer material. Develop in the first order, and in the second and subsequent steps, cyan toner,
An image forming method characterized in that an image is formed by developing a yellow toner and a magenta toner.