JPH02293866A - Color image forming method - Google Patents

Abstract

PURPOSE:To obtain well balanced hues and spectral reflection characteristics and sufficient saturation by respectively specifying the components of respective color toners; magenta, cyan, yellow, and black. CONSTITUTION:The magenta toner has polyester resin particles contg. a quinacridone pigment and a xanthene dye treated with a phenolic resin and a flow improving agent. The cyan toner has polyester resin particles contg. a copper phthalocyanine blue pigment and the flow improving agent. The yellow toner has polyester resin particles contg. an azo yellow pigment and the flow improving agent and the black toner has a polyester resin contg. a carbon black as a coloring agent and the flow improving agent. The well balanced hues and spectral reflection characteristics and the sufficient saturation are obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming method for a full-color copying machine.

[Prior Art] In recent years, there has been a rapid shift from monochrome copying to full-color copying in copying machines and the like, and two-color copying machines and full-color copying machines have been extensively studied and put into practical use. For example, “Journal of Electrophotography Society J Vol22, No.
l (1983) and “Journal of Electrophotography Society” Vol. 25, N
o1, P52 (1986). There are also reports on color reproducibility and gradation reproducibility.

However, unlike television, photographs, and color printed matter, there is no immediate comparison with the real thing, and for people who are used to seeing color images that are more beautifully processed than the real thing, full-color electrophotography, which is currently in practical use, is is not always satisfactory.

Color image formation by full-color electrophotography generally requires 3
The primary colors are yellow and magenta. All colors are reproduced using three cyan color toners.

In this method, first, light from an original is passed through a color-separating light transmitting filter having a complementary color to the toner color to form an electrostatic latent image on a photoconductive layer. Next, develop. The toner is retained on the support through the transfer process. Next, the above-mentioned steps are repeated several times in order, and the toners are superimposed on the same support while registering, and a final full-color image is obtained by one fixation. The developing method used at this time is US Pat.
Cascade development method described in No. 18,552, U.S. Pat.
, 874,063, and other touchdown methods.

Among these, the most commonly used method is the magnetic brush method. The method uses steel as a carrier. Particles having 6n properties such as ferrite are used.

A developer consisting of toner and magnetic carrier is held by a magnet, and the magnetic field of the magnet arranges the developer in a brush shape. When the magnetic brush contacts the electrostatic latent image surface on the photoconductive layer, only toner is attracted from the brush to the electrostatic latent image to effect development.

However, this method has extremely low development efficiency because the proportion of consumable toner in the magnetic brush in the development section is small. For example, only 1 to 5% of the total developer may be used. Furthermore, if a large amount of developer is used to increase the developing efficiency, the developing device becomes larger and heavier, making it impossible to make the copying machine smaller and lighter.

In particular, since a full-color copying machine requires at least three of the above-mentioned developing devices, it is impossible to make the full-color copying machine more compact.

In terms of image quality, scratches caused by the magnetic brush appear on the developed image like sweeping marks, and due to the strong mixing of toner and carrier inside the developing device, charging deterioration occurs and toner adheres to non-image areas, causing so-called fog. It has problems such as easy to appear.

In color electrophotography, which requires multiple development steps and the overlapping of several toner layers of different colors on the same support, the following are necessary and sufficient conditions that color toners should have: It will be done.

(1) The fixed toner must be almost completely melted to the point where the shape of the toner particles cannot be discerned, so that it does not diffusely reflect light and interfere with color reproduction. The colored toner must have a transparency that does not interfere with the different toned toner layers below the toner layer.

(2) Each of the constituent toners must have well-balanced hue and spectral reflection characteristics and sufficient saturation.

Furthermore, the electrophotographic properties of the toner include the following.

(3) Each toner needs to have approximately the same amount of triboelectric charge and also have good charging characteristics with less environmental dependence. (4) Favorable conveyance and mixing properties are required to allow smooth replenishment from the hopper to the developing device and to facilitate mixing with the carrier and developer.

However, at present, there is no color development method that satisfies all of the above-mentioned properties.

For example, as proposed by the present applicant in Japanese Patent Application Laid-Open No. 59-26757, a color toner kit consisting of three types of toner of three primary colors is used as a full-color toner.

However, while these combinations are relatively balanced for color reproduction, their electrophotographic properties are
There are still points that need to be improved in terms of charging characteristics other than storage stability and durability against repeated copying. Furthermore, in the above proposal, in order to obtain black by superimposing three colors of toner, subtle differences in tone between these three colors and differences in superposition during development, transfer, and constant adhesion are reflected in the black tone, and toner manufacturing The complexity of color matching of each color toner during the process, and the need for high precision in the development, transfer and fixing steps of the copying process, naturally complicate the process and cause an increase in costs.

The applicant has also previously proposed full color toner kits and developers, color toner compositions, and image forming methods.

In this method, each of the constituent toners has a well-balanced hue, spectral reflection characteristics, and sufficient chroma, but since the magenta toner uses a dye-based colorant, ■ a pigment-based colorant is used. Compared to the yellow toner, cyan toner, and black toner used, the amount of triboelectric charge is slightly different, and the environmental dependence of the charging characteristics is also slightly different. Therefore, in halftone images that require delicate color balance, this requirement has not been fully satisfied.

■ The light resistance of the colorant is inferior to that of pigment-based coloring.

Therefore, when saving a full-color image, only the magenta color gradually fades due to light irradiation, resulting in an image with poor color balance.

(2) Furthermore, if a copy image is sandwiched between a vinyl chloride mat, the dye in the toner tends to contaminate the vinyl chloride mat. This means that the carrier and sleeve may be contaminated during development, reducing the development characteristics of the toner, and the so-called offset phenomenon, in which colorant adheres to the fixing roller during the fixing process of a copying machine, is likely to occur. be. Therefore, there are drawbacks such as deterioration of developing characteristics and worsening of fog due to carrier contamination, smearing of copied images due to offset, and shortening of the life of the fixing roller. Therefore, it is desirable to apply a pigment with excellent light resistance to the magenta toner. However, as the applicant demonstrated in the above-mentioned comparative example, with the toner using only the magenta pigment, the resulting image has poor chroma. This results in poor color reproducibility.

Furthermore, although it is possible to increase the saturation with a magenta toner based on a combination of pigment and dye, it has drawbacks because it is a combination system.

The reason is that the dye and pigment used have poor affinity, so they repel each other in the binder resin during the dispersion process, making it difficult to achieve a uniform color tone. In addition, since the compatibility of each dye and pigment with the binder resin is not uniform, both dyes and pigments will not be in the same dispersion state at the same time.
Separation of the dye is likely to occur due to poor dispersion of the pigment or because the dispersion time is too long. If a toner with colorants unevenly distributed in this way is used as a toner, it will have poor charging characteristics for electrophotography, cause fogging, cause contamination due to toner scattering inside the machine, and even reduce the transparency of OHP images. ．． In other words, magenta toner, cyan toner. In multicolor electrophotography using yellow toner and black toner, each toner has a well-balanced hue and sufficient saturation, the triboelectric charging characteristics of each toner are almost the same, and the development characteristics of each toner are At present, there is no color image forming method that does not reduce the quality.

Furthermore, in recent years, for example, Japanese Patent Application Laid-Open No. 62-299869
As disclosed in No. 1, etc., it is desired to reduce the toner particle size for the purpose of improving the quality of copied images.

However, although it is possible to improve the resolution and sharpness of a full-color image by simply reducing the toner particle size, various problems arise due to the small particle size.

First of all is the dispersion of the colorant mentioned above. If you reduce the toner particle size, that's it. It is a truism that charging characteristics are easily affected by the uneven distribution of colorants. Therefore, there is a need for a toner that includes not only magenta but also colorants of other colors and has good dispersion, well-balanced hue and spectral reflection characteristics, and sufficient saturation.

Furthermore, since the surface area of the toner is increased by reducing the particle size of the toner, the charging characteristics of the toner become more susceptible to the influence of the environment.

Furthermore, as the particle size of the toner is reduced, the surface area increases, which deteriorates toner transportability and scattering. Furthermore, fogging becomes worse as the particle size of the toner becomes smaller.

At present, there is no full-color toner or developing method for the same that can satisfy all of the various problems described above.

[Problems to be Solved by the Invention] However, an object of the present invention is to provide a color image forming method that solves the above-mentioned problems and can also be used with toner having a small particle size.

That is, the object of the present invention is to produce magenta toner and cyan toner.
The present invention provides a color image forming method using toners having balanced hue and spectral reflection characteristics and sufficient saturation in yellow toner and black toner.

Another object of the present invention is to provide a method for forming a color image using magenta toner, cyan toner, yellow toner, and black toner having excellent light resistance.

Another object of the present invention is to provide a color image forming method using magenta toner, cyan toner, yellow toner, and black toner that have charging characteristics with excellent environmental stability.

Another object of the present invention is to provide a color image forming method using a heated roller fixation toner that has good fixing properties and particularly good anti-offset properties.

Another object of the present invention is to provide a color image forming method using magenta toner, cyan toner, yellow toner, and black toner that have good transportability.

Another objective is to create a magenta toner with less scattering and fog. An object of the present invention is to provide a color image forming method using cyan toner, yellow toner, and black toner.

[Means and effects for solving the problems] The present invention is characterized in a color image forming method using multicolor electrophotography using magenta toner, cyan toner, yellow toner, and black toner. The magenta toner is a toner having polyester resin particles containing a xanthene dye treated with a quinacridone pigment and a phenol resin, and a flow improver, and the cyan toner is a toner containing a polyester resin particle containing a copper phthalocyanine blue pigment. A toner having particles and a flow improver, the yellow toner being a toner having polyester resin particles containing an azo yellow pigment and a flow improver, and the black toner having polyester resin particles containing carbon black as a colorant. A color image forming method using a toner containing a resin and a fluidity improver, using a jumping and brush (J/B) development method in which the toner adhering to the developing sleeve and carrier surface is transferred to a photosensitive drum for development. It is in.

The applicant has previously shown that it is important for the color reproducibility of full-strength toner that each color toner falls within a certain chromaticity range.

In particular, magenta toner has the above-mentioned drawbacks. As a coloring agent, (1) If only a pigment is used, the color reproducibility will not fall within a good chromaticity range, and the copied image will be desaturated.

(2) In addition, when using only a dye, light resistance and development characteristics are poor. PVC resistance. Poor fixing properties.

(3) In addition, when a pigment-dye combination system is used, the dispersion of the colorant is poor, resulting in poor developability. This results in poor translucency. However, as a result of intensive studies, the present inventors have found that by using a pigment-dye system and a dye treated with a resin, migration of the dye can be prevented, and furthermore, the pigment has good light resistance. Development characteristics. PVC resistance. without compromising fixity,
This makes it possible to obtain a magenta toner with good color reproducibility within the chromaticity range.

The inventors of the present invention inferred the reason for this as follows.

This treated dye is made by incorporating and dispersing chitin-based dye into the phenol resin.
The state in which these are dispersed in the toner is not that the xanthene dye alone is dissolved and dispersed in the toner, but that the phenolic resin that has been dyed and dispersed is dispersed in the toner. It is thought to take . in this case,
The xanthene dye is encapsulated and retained in the phenolic resin and does not migrate into the toner and adversely affect the development characteristics of the toner, and the staining of the fixing roller is significantly reduced, and the resistance to vinyl chloride staining is improved.

In particular, when a dye that is not treated with a resin is used, the xanthene dye present on the toner surface reduces the toner's chargeability. Since the toner is present and does not deteriorate the charging characteristics, the toner charging characteristics due to environmental changes are stable, and therefore it is thought that fogging, scattering, etc. will be improved.

Furthermore, the present inventors proposed the use of carbon black as a coloring agent for a full-color black toner.

A black toner using such carbon black has high hiding power, and the area where the four colors of toner overlap exhibits a deep black color. Therefore, when copying photographs, etc.,
Color increases.

Hereinafter, the present invention will be specifically explained in detail.

An example of a full-color electronic copying machine to which a color electrophotographic method according to the present invention is applied will be described with reference to FIG.

The electrostatic latent image formed on the photosensitive drum 1 by a suitable means is visualized by the developer in the developing device 2-1 attached to the rotary developing unit 2 which rotates in the direction of the arrow. This developed toner is transferred by a transfer charger 8 onto a transfer material held on a transfer drum 6 by a gripper 7.

Next, the rotary developing unit rotates as the second color, and the developing device 2
-2 faces the photosensitive drum 1. The toner is then developed with the developer in the developing device 2-2, and this developed toner is also transferred onto the same transfer material as described above. Another third color. The fourth color is done in the same way. In this way, the transfer drum 6 rotates a predetermined number of times while holding the transfer material, and images of a predetermined number of colors are transferred multiple times. Transfer material with multiple transfers is only 1 minute! ! It is separated from the transfer drum 6 by an electric device 9,
After passing through the fixing device 10, it becomes the final full-color copy image. Further, replenishment toner supplied to the developing units 2-1 to 2-4 is supplied from a replenishment hopper 3 provided for each color in a fixed amount based on a replenishment signal via a toner conveying cable 4 to the rotary developing unit 2. The toner is transported to the toner replenishment cylinder 5 located at the center and sent to each developing device. This replenishment toner is uniformly mixed in advance with the developer in the developing device so as to have a predetermined developer concentration within the developing device.

Then, in accordance with the signal from the developer concentration detector, the supply screw l6 in the toner conveying cable 4 rotates for a certain period of time to replenish toner from the replenishment hopper 3 to the developing device 2.

As a developing method, a two-component developing method may be used, but the jumping and brush developing method described below improves image quality, especially fogging. It is more preferable in terms of sweeping traces.

That is, a bias electric field consisting of an alternating current component and a direct current component is applied between the developing sleeve 13 and the photosensitive drum 1 having the electrostatic latent image, and a bias electric field consisting of an AC component and a direct current component is applied to the volume of the space formed by the developing sleeve l3 and the photosensitive drum 1. The volume occupied by the carrier in the developing section of the developing sleeve l3 is 1.5 to 40%, preferably 2.0 to 30%, and the electric field of the alternating current component is
000 to 3 0 0 0 11 z, and the peak-to-peak voltage is set so as not to destroy the electrostatic transfer image and in the development area,
A voltage is applied to move the carrier between the developing sleeve 13 and the photosensitive drum 1, and in the developing section, the developing sleeve 13
This is a method in which the upper toner and the toner adhering to the carrier surface are transferred to the photosensitive drum 1 for development.

The composition of the full color toner polyester resin used in the present invention is as follows. That is, such a composition has 45 to 55 ffloj of all components! % is the alcohol component and 55-45 moR% is the acid component.

Alcohol components include ethylene glycol and brobylene glycol. 1,3-butanediol, 1,4-butanediol, 2,3-butanediol. Diethylene glycol. Triethylene glycol. 1.5-pentanediol. 1,6-hexanediol. Neoventyl glycol. 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, or a bisphenol conductor represented by the formula (A); (wherein R is an ethylene or propylene group, and x and y are each an integer of 1 or more Yes, and
(The average value of x+y is 2 to 10) Also, diols represented by formula (B); diols such as glycerin. Examples include polyhydric alcohols such as sorbitol and sorbitan.

In addition, examples of divalent carboxylic acids containing 50% or more of the total acid components include phthalic acid. Terephthalic acid. Isophthalic acid. Benzenedicarboxylic acids or their anhydrides such as phthalic anhydride; succinic acid. Adivic acid, sebacic acid. Alkyl dicarboxylic acids such as azelaic acid or its anhydride; succinic acid or its anhydride substituted with an alkyl group having 6 to 18 carbon atoms; fumaric acid, maleic acid.
Citraconic acid. Examples include unsaturated dicarboxylic acids such as itaconic acid or their anhydrides, and examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, penzophenonetetracarboxylic acid, and their anhydrides. .

The alcohol component of the polyester resin which is particularly preferred for carrying out the present invention is a bisphenol derivative represented by the above formula (A), and the acid component is phthalic acid. Terephthalic acid. Isophthalic acid or its anhydride; succinic acid. Rhodecenylsuccinic acid or its anhydride. Examples include dicarboxylic acids such as fumaric acid, maleic acid, and maleic anhydride, and tricarboxylic acids such as trimellitic acid or its anhydride.

This is because polyester resins obtained with these acids and alcohols exhibit sharp melting characteristics, good color mixing properties as toners for full color use and constant wear on a hot roller, and excellent anti-offset properties.

Furthermore, the glass inversion temperature of the polyester resin obtained here is 50 to 75°C, preferably 55 to 65°C, and the number average molecular weight Mn is 1,500 to 7,000, preferably 2,000 to 5,000, and the weight Average molecular weight Mw 6
,000 to 15Q,QQO preferably 10. OQO~
Preferably, it is 100,000.

Further, it is desirable that the acid value is 90 or less, preferably 50 or less, and the OH value is 50 or less, preferably 30 or less. This is because as the number of terminal groups in the molecular chain increases, the charging characteristics of the toner become more dependent on the environment when it is made into a toner.

The magenta quinacridone pigment and xanthene dye used in the present invention are as follows.

Typical examples of quinacridone pigments include Structural Formula C. Typical examples of xanthene dyes used in the present invention include Structural Formula C. I. Basic Violet 11:1
and so on. Among them ■C. I. Pigment Red
122 is particularly used as a magenta coloring agent.

can be mentioned.

All of ■ to ■ have a clear bluish pink color.

■． ■Because it is a basic dye, it has some hygroscopicity.
Furthermore, considering the compatibility with the resin, in the present invention,
C.I. is oil-soluble, has excellent compatibility with resins, and has high coloring power. I. Solvent Red 49. is particularly suitable.

Furthermore, the phenolic resin for xanthene dye treatment used in the present invention includes the following as its 1,000-nomer composition.

Phenols include phenol, cresol, xylate, and alkylphenol. Rose phenylphenol. Bisphenol A, etc., and aldehydes such as formaldehyde, paraformaldehyde. All known materials such as hexamethylenetetramine and furfural can be used. Among these, it is particularly preferable to use a phenol resin, which is a metal condensate of tert-butylphenol and formaldehyde, because the dye is dispersed in a good state. The method of treating the xanthene dye with the phenol resin in the present invention is as follows: (1) The xanthene dye and the phenol resin are mixed in a two-roll mill. Banbury mixer. A method of melting and kneading using a kneader, Miki roll mill, etc.; (2) dissolving the phenol resin in a suitable solvent, dissolving or dispersing the xanthene dye therein, and then removing the solvent;
(3) A method of dissolving and dispersing a xanthene dye in a mixture of phenol and formaldehyde, adding an alkali and heating it to make it three-dimensional; (4) A method of dissolving and dispersing a xanthene dye in a mixture of phenol and formaldehyde, and One method is to prepare a novolac resin under a catalyst and then cure it by adding a crosslinking agent such as hexamethylenetetramine.

The xanthene dye treated with the phenol resin by these methods is dried and pulverized, and then melted and kneaded with a polyester resin as a binder resin to be uniformly dispersed.

Further, in the present invention, when treating a xanthene dye with a phenol resin, a quinacridone pigment can also be dispersed and treated in the same manner as the xanthene dye.

Further, in the present invention, the ratio of the phenol resin for treatment to the xanthene dye is 100:10-100.
:200 is preferable. This is because, as a result of detailed studies by the present inventors, when the ratio of phenol resin to dye is less than 100:10, the treatment effect of the phenol resin, such as the effect of preventing dye migration, as described above, is almost lost. It is known that phenol resin is inherently susceptible to discoloration due to heat, oxygen, etc., but conversely, if the ratio of phenol resin is greater than 100:200, the color of the discolored phenol resin will significantly reduce the image quality of the copied image. .

Therefore, processing within the above usage range is very effective in preventing dye migration without degrading copy image quality.

The copper phthalocyanine blue pigment used in the present invention includes C.I. I. Pigment Blue 15, C. I. Pigment Blue-1 [i, C.I. I. Pigment Blue-17 or a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton having the structure shown by formula (1).

■Copper phthalocyanine pigment n=i ~5 As the azo yellow pigment used in the present invention, C.I. I.
Pigment Yellow 1, C. I. Pigment Yellow 2, C. ! ．． Pigment Yellow 3, C. ! ．． Pigment Yellow 4, C. I. Pigment Yellow 5, C.
! ．． Pigment Yellow 6, C. I. Pigment Yellow 7, C. I. Pigment Yellow 10, C. I. Pigment Yellow 11, C. I. Pigment Yellow 12. C. 1. Pigment Yellow 13, C. I. Pigment Eye Mouth-14, C. I. Pigment Yellow 15, (:.I. Pigment Yellow 17, etc.).

The content of the colorant is 12 parts by weight or less, preferably 0.5 to 7 parts by weight, based on 100 parts by weight of the binder resin, for yellow toner that sensitively affects the transparency of the OHP film. desirable.

If it exceeds 12 parts by weight, green, which is a mixed color of yellow. Red, and as an image, it has poor reproducibility of human skin color.

For other magenta (combined amount of pigment and resin-treated dye used) and cyan color toners, the amount is 15 parts by weight or less, more preferably 0.1 to 9 parts by weight, per 100 parts by weight of the binder resin. desirable.

Further, in the case of magenta, in order to take advantage of only the advantages of the dye and pigment described above, it is preferable that the usage ratio is within the following range.

Resin treatment dye amount: pigment = 1: 100 to 10:1, more preferably 1:50 to 5:1.

In particular, for black toners that use two or more colorants in combination, adding a total colorant amount of 20 parts by weight or more not only tends to cause the colorant to be spent into the carrier, but also causes a large amount of the colorant to be exposed on the toner surface. This also increases concerns about toner drum fusing and fixing performance. Therefore, the amount of the colorant is preferably 3 to 15 parts by weight per 100 parts by weight of the binder resin.

The particle size of carbon black used as a colorant for black toner is 50 to 70 mp, preferably 50 to 60 mp.
μ. Toner containing carbon black with a particle size of less than 50 mμ has a yellowish chromaticity, which not only makes it impossible to obtain a sharp black color, but also makes it extremely difficult to disperse carbon black, which is exposed on the toner surface. The resulting carbon black becomes non-uniform. As a result, the adhesion of the fluidity improver deteriorates and the fluidity is significantly reduced, making it impossible to obtain a good amount of triboelectric charge, resulting in fogging and toner scattering. Further, if the particle size exceeds 70 mP, the blackness of the carbon black is low, and an image exhibiting a vivid black color cannot be obtained.

In addition, the oil absorption amount of this carbon black is 50 to 100
cc/100g, preferably 80 to 80cc71
00g. When the oil absorption amount exceeds 100cc7100g, the structure of carbon black becomes long, the conductivity increases, and the amount of triboelectric charging of the toner decreases.
This may cause fogging or scattering. Also, the oil absorption amount is 50cc/1
If it is less than 00 g, high image density cannot be obtained.

The carbon black contained in the resin binds to the binder resin 1.
00 parts by weight, 2.1 to 10.0 parts by weight, preferably 3.0 to 6.0 parts by weight. If the carbon black content is less than 2.1 parts by weight, high image density cannot be obtained and the uniformity of the solid area deteriorates, and if it exceeds 10.0 parts by weight, sufficient triboelectric charge cannot be obtained. do not have.

In measuring the physical properties of the carbon black, the particle size was measured by directly and selectively counting the particle size in a scanning electron micrograph.

The method for measuring oil absorption is as described below.

It is also preferable to add a charge control agent to the toner according to the present invention in order to stabilize the negative charge characteristics. In this case, a colorless or light-colored negative charge control agent that does not affect the color tone of the toner is preferred. Examples of negative charge control agents include organometallic complexes such as metal complexes of alkyl-substituted salicylic acids (eg, chromium complexes or zinc complexes of tertiary butyl salicylic acid). When a negative charge control agent is added to the toner, it is added in an amount of 0.000 parts by weight per 100 parts by weight of the binder resin.
It is good to add 1 to 10 parts by weight, preferably 0.5 to 8 parts by weight.

Magenta toner obtained using the above-mentioned materials. The particle size distribution of the classified products of cyan toner, yellow toner, and black toner (colorant-containing resin particles without fluidity improvers such as silica, v&aluminum oxide, and titanium oxide, which will be described later) is as follows:
The volume average particle size is 4.0 to 16.0 μm, preferably 6
．． 0 to 14.0 gm, the number average distribution of 5.04 μl or less is 50% or less, preferably 40% or less, and the volume average distribution of 20.2 μm or more is 9% or less, preferably 5%.
or less, and furthermore, the ratio α of volume average particle size to number average particle size (α = volume average particle size/number average particle size) is 1.7 or less,
Preferably, it is 1.4 or less. This has a volume average particle size of 18. Beyond Ou1 and/
Alternatively, if the volume average distribution of 20.2 μm or more exceeds 9%, there is an increased tendency for so-called skipping, such as roughness of images and blurring of characters, to worsen.

In addition, if the volume average particle size is less than 4.0 μm and/or the number average particle size of 5.04 μm or less exceeds 50%, the amount of toner scattering will increase, especially in a high temperature and high humidity environment, and the charger wire will be damaged. Contamination, contamination of part of the developer concentration detector fiber. Furthermore, the accumulation of flying debris on the sliding parts may cause the machine to become unable to move. In addition, particularly in low temperature and low humidity environments, the amount of triboelectric charge per toner particle becomes extremely large, resulting in a decrease in the amount of toner developed on the image area of the electrostatic latent image on the photosensitive drum, resulting in a decrease in the amount of toner that is developed on the electrostatic latent image on the photosensitive drum. The resulting copied image may have low density or poor color reproduction. Furthermore, if even a small amount of the electrostatic latent image scatters and adheres to the non-image area of the photosensitive drum, it often causes fogging and poor cleaning.

Furthermore, when the ratio α of the volume average particle size to the number average particle size exceeds 1.7, the particle size distribution is wide, and the triboelectrification distribution of the toner is also wide, resulting in reverse polarity charging (in the present invention, positive (Charged) A large amount of toner is generated. This results in an image with poor fog. As the fluidity improver used in the present invention, any fluidity improver can be used as long as the fluidity improves when added to the colorant-containing resin particles when comparing before and after addition.

For example, fluororesin powder, such as vinylidene fluoride fine powder, polytetrafluoride fine ethylene powder, etc.; or fatty acid metal salts, such as zinc stearate, calcium stearate, lead stearate, etc.; or metal oxides, such as aluminum oxide, titanium oxide, etc. , zinc oxide powder, etc.; or finely powdered unsilica, that is, wet-processed silica, dry-processed silica, and treated silica in which these silicas are surface-treated with a silane coupling agent, a titanium coupling agent, silicone oil, etc.

A preferred flow improver is a fine powder produced by vapor phase oxidation of a silicon halide compound, so-called dry process silica or fumed silica, which is produced by conventionally known techniques. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.

SiCR4+ 2 H2 + Ox → 510, + 4
Htl:j Also, preferred flow improvers include aluminum oxide and titanium oxide, which are obtained in the same manner as in the above manufacturing process.

The particle size is 0.001 to 2 μm as the average primary particle size.
It is desirable that it be within the range of 0.0, particularly preferably 0.0
It is preferable to use fine powder within the range of 0.02 to 0.2 μm.

Commercially available silica fine powders produced by vapor phase oxidation of silicon halogen compounds used in the present invention include those commercially available under the following trade names, for example.

AEROSI1 130 (
Japan Aerosil Co.) 200 TTIi00 MOX170 MOX 80 COκ 84 Ca-0-SiL (CABOT Co.) M- 5 MS- 7 MS-75 HS- 5 El{- 5 Wacker HDK N 20 (WACKE
R-CHEMIE GMBH) V15 N2GE T30 T40 D-C Flne Silica (Dow Corning Co.) Fransol (Fransll) Furthermore, the silica fine powder produced by gas phase oxidation of the silicon halogen compound was subjected to hydrophobization treatment. It is more preferable to use treated silica fine powder.

Among the treated silica fine powders, it is particularly preferred that the silica fine powders be treated so that the degree of hydrophobicity as measured by a methanol titration test is in the range of 30 to 80.

Hydrophobicity can be imparted by reacting with fine silica powder or by chemically treating it with an organosilicon compound that physically adsorbs it.

In a preferred method, fine silica powder produced by vapor phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane,
Allyl phenyldichlorosilane, benzyldimethylchlorosilane, prommethyldimethylchlorosilane, α-chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercabutane, trimethylsilylmercabutane, triorganosilyl Acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane,
Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and siloxane units containing 2 to 12 siloxane units per molecule, one each for the terminally located unit. Examples include dimethylborisiloxane containing a hydroxyl group bonded to Si. These are 1 fil or 2 fi! Used in mixtures of the above.

The particle size of the treated silica fine powder is 0.003-0.
It is preferable to use one in the range of 1 μm.

Commercially available products include Taranox 500 (Talco)
, AEROSIL R-972 (Japan Aerosil Co., Ltd.), etc. The amount added to the colorant-containing resin particles is 1
0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight. If it is less than 0.01 parts by weight, it will not be effective in improving fluidity, and if it exceeds 10 parts by weight, it will promote fogging, smearing of letters, and scattering inside the machine. As carriers used in the present invention, surface oxidized or unoxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earths, and their alloys or oxides and ferrites can be used. Moreover, there are no special restrictions on the manufacturing method.

Further, a system in which the surface of the carrier is coated with a resin or the like is particularly preferred in the above-mentioned J/B development method. As a method for this, any conventionally known method can be applied, such as a method in which a coating material such as a resin is dissolved or suspended in a solvent and applied and adhered to the carrier, or a method in which a powder is simply mixed. Substances that adhere to the carrier surface vary depending on the toner material, but include, for example, polytetrafluoroethylene, monochrome trifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of ditertiary butylsalicylic acid, and styrene. It is appropriate to use resins, acrylic resins, boriacids, polyvinyl butyral, nigrosine, aminoacrylate resins, basic dyes and their lakes, fine silica powder, fine alumina powder, etc. alone or in combination, but there are no restrictions on this. Not done. The amount of the above-mentioned compound to be treated may be appropriately determined so that the carrier satisfies the above conditions.
201i amount%) is desirable.

These carriers have a 25o mesh bath, 400 mesh on, have a concentration of 70 fH% or more, and have an average particle size of 10 to 100 um, preferably 20 to 7
It is preferable to have 0 um.

A particularly preferred embodiment is a ternary ferrite of Cu-Zn-Fe, the surface of which is coated with a styrene resin or a styrene resin. Examples include those coated with a resin. These resins not only have a high ability to impart FJ triboelectric charge to the toner in the color development method of the present invention, but also have a stable ability to impart triboelectricity that is not easily affected by the environment.

As the styrene resin, any resin obtained using polystyrene or a monomer that can be polymerized with styrene can be used, but preferred resins include styrene-acrylic resins, particularly styrene-methyl methacrylate resins, and styrene-acrylic resins. Examples include 2-ethylhexyl acrylate, styrene-2-ethylhexyl acrylate-methyl methacrylate, and the like. As the fluororesin, any fluorine-containing vinyl resin can be used, but particularly preferred resins include polyvinylidene fluoride, polytetrafluoroethylene, and vinylidene fluoride-tetrafluoroethylene copolymer. It will be done. The coating amount of these resins on ferrite is 0.01 to 10! i amount%, preferably 0.05
~5% by weight. In addition, when using styrene resin and fluororesin together,
The content of the fluororesin in the coating agent is desirably 90% by weight or less, preferably 70% by weight or less.

This is because if the resin coating amount exceeds 10% by weight, the carrier will coagulate, and if it is less than 0.01% by weight, there will be a large amount of uncoated area, and some toner will be charged by friction. This is because the amount decreases and fog becomes worse.

Furthermore, if the amount of fluororesin used in the coating agent exceeds 90% by weight, the ferrite will not be coated well and only the resin will be liberated. Therefore, the amount of fluororesin used in the coating agent is preferably 90% by weight or less. The coated ferrite carrier has a sharp particle size distribution, provides favorable triboelectric charging properties for the color toner kit of the present invention, and has the effect of improving electrophotographic properties. When preparing a two-component developer by mixing with the color toner according to the present invention, the mixing ratio is 2.0% by weight to 15.0% by weight, preferably 3.0% by weight in terms of toner concentration in the developer.
Good results are usually obtained between % and 13.0% by weight. If the toner concentration is less than 2.0%, the image density will be too low to be practical; if it exceeds 15%, fogging and in-machine scattering will increase, and the useful life of the developer will be shortened.

Below, each measurement method in the present invention will be described.

(1) Measurement of glass transition temperature Tg In the present invention, measurement is performed using a differential thermal analysis measuring device (DSC measuring device), DSC-7 (manufactured by PerkinElmer).

The sample to be measured is accurately weighed in an amount of 5 to 20 mg, preferably 10 II lg.

This is placed in an aluminum pan, and using an empty aluminum pan as a reference, measurement is performed at room temperature at a temperature increase rate of 10° C./akin within a measurement temperature range of 30° C. to 200° C.

In this temperature raising process, a main endothermic peak in the temperature range of 40 to 100°C is obtained.

The intersection point between the line at the midpoint of the base line before and after the endothermic peak appears and the differential heat curve is defined as the glass transition temperature Tg in the present invention.

(2) Measurement of molecular weight distribution In the present invention, high performance liquid chromatography (JASCO TRI ROTAR-VI HPL manufactured by JASCO Corporation)
Csystem). The column is Toso TSK gel-2000, -3 manufactured by Toyo Soda Kogyo Co., Ltd.
000, -4000, -5000, and the solvent is T
HF was used. The Detector is manufactured by Showa Denko Sh.
odex RISE-51, and the measurement conditions were Now
rate is 1. Omj! /min, column temperature 40
℃, InJvol. I went with 75gj. The molecular weight of the sample was calculated from the relationship between the logarithm value and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples to determine the molecular weight distribution of the sample.

As a standard boristyrene sample for preparing a calibration curve, for example, Pressure Chemical Go. manufactured by Toyo Soda Kogyo Co., Ltd. with a molecular weight of 6 x 102, 2
．． 1x 103,4 XI+13, 175 xlO'
, 5.1x10' 1. lxlO'3.9X 10
', 8. BX 10', 2 X 10', 4.
It is appropriate to use a 48 x 10' polystyrene sample and at least 10 standard polystyrene samples. (3) As a particle size distribution measuring device, a Coulter Counter TA-II model (manufactured by Coulter Co., Ltd.) is used, and an interface (manufactured by Nikkaki Ki Co., Ltd.) that outputs the number average distribution and volume average distribution and a C×-
1 Connect a personal computer (manufactured by Canon) and prepare a 1% NaCj aqueous solution using primary sodium chloride as the electrolyte. As a measurement method, the electrolytic aqueous solution 100 to 1
Add 0.1 to 5 mj of a surfactant as a dispersant, preferably an alkylbenzene sulfonate, to 5 Oaj, and further add 0.5 to 50 mg of the sample to be measured. The electrolyte in which the sample was suspended was dispersed using an ultrasonic disperser for about 1 to 3 minutes.
With the Coulter counter TA-11 type, a 100 μm aperture was used as the aperture, and 2 to 40 μI.
Measure the particle size distribution of the particles and find the volume average distribution and number average distribution. From the volume average distribution and number average distribution obtained, the volume average particle diameter and number average particle diameter are determined. 5 of number average distribution
. Obtain each value of 0.04 μm or less and 20.2 μm or more of the volume average distribution.

(4) Measurement of oil absorption (DBP method) Oil absorption is measured in accordance with ASTM method D 2414-79. Operate the cock of the absorbometer to completely fill the automatic burette system with DBP (dibutyl phthalate) so that no air bubbles remain, and set the specifications of the device to the following conditions.

■ Spring tension 2.68 kg/cm ■ Rotor rotation speed 125 rpm ■ Torque limit switch scale 5 ■ Damper valve 0.15
0 ■ DBP dropping rate 4 ml/winDBP
After adjusting the dropping rate by actual measurement, put a certain amount of dry sample into the absorbometer mixing chamber, set the bullet counter to point O, and set the switch to automatic to start dropping. When the torque reaches the set point (5 in this case), the limit switch is activated to automatically stop dripping, read the scale (V) on the bullet counter at that time, and calculate the oil absorption amount using the following formula.

■ OA= -X IQQ W OA=Oil absorption amount (mj/100g) V: DB used up to the end point (limit switch activation point)
Amount of P used (mβ) W: Weight of dry sample (g) [Examples] The present invention will be explained in detail below with reference to Examples.

Yi! {+l11 Polyester resin obtained by condensing proboxylated bisphenol and fumaric acid (M n x 3,000, M
Stomach = 17,000, g = 57℃. Acid value = 90, 0
A full color toner was obtained using 100 parts by weight of 14 valence = 17) and the prescribed amounts of colorant and charge control agent shown in Table 1 below. (Left below) The manufacturing method was the masterbatch method. First, polyester resin and an amount 6 times the amount of the coloring agent mentioned above were melt-kneaded in a three-roll mill, and after cooling, they were mixed in a 1 mm thick mixture in a hammer mill.
The powder was coarsely crushed to obtain a colored resin for a master patch. Next, the polyester resin, the charge control agent, and the colored resin for the masterbatch were weighed out to the predetermined amounts and premixed using a Henschel mixer. After that, it is melt-kneaded with a three-roll mill, and after cooling, it is mixed with a hammer mill for about 1 to 2 nm.
The mixture was coarsely pulverized to about +m, and then finely pulverized to a particle size of 30 μm or less using an air jet type pulverizer.

Furthermore, the obtained finely pulverized material was classified, and for magenta toner, the volume average particle size was 8.20 μm, and the number average particle size was 6.
．． 35 μm (therefore, α=1.29), 30.0% of the number average distribution is 5.04 μm or less, and 20.0% of the volume average distribution.
2μm or more was adjusted to 0.1%. Regarding other toners,
The particle size distribution is shown in Table 2. 0.5 fi parts of fine silica powder treated with hexamethyldisilazane as a flow improver was added to 100 parts by weight of each classified product. 0.2 parts by weight of aluminum oxide fine powder was externally added to prepare a full color toner.

(Left below) As the carrier, styrene-2-ethylhexylacrylate-methyl methacrylate (copolymerization weight ratio 50:
20:30) coated with 0.5% by weight of Cu
-Zn-Fe ferrite carrier (average particle size 4l.5
μm; 250 mesh pass 400 mesh on 85.5
% by weight) to prepare a developer so that the toner concentration of each color was 5% by weight.

Using these developers and toners, an image reproduction test was conducted using a Canon full-color copying machine CLC-1. As a result, even after printing 15,000 sheets in full-color mode, there was no offset to the fixing roll, and a full-color image that faithfully reproduced the original color chart without fogging was obtained. In addition, the black image area exhibited a deep black color with excellent concealment properties. Further, the toner transportability within the copying machine was good, and stable image density was obtained. Even when OHP film was used, the toner permeability was very favorable. Further, image printing tests were carried out by changing the environment to low temperature and low humidity, high temperature and high temperature, and good results were obtained, with stable image density, no fogging, and almost no toner scattering.

In addition, the images obtained here were exposed to sunlight for 3 months,
None of the colors faded, and the image remained the same as when it was printed. To 100 parts by weight of each classified toner obtained in Example 1, 0.6 parts of fine silica powder treated with hexamethyldisilazane was added.
Weight part. A full color toner was prepared by externally adding 0.2 parts by weight of titanium oxide. Other than that, the same procedure as in Example 1 was carried out.
Image reproduction tests were conducted using a Canon full-color copier (LC-1).As a result, no offset occurred even after printing 10,000 sheets in full-color mode, and the original color chart was faithfully reproduced without fogging. A full-color image was obtained.Also, the black image area exhibited a deep black color with excellent hiding properties.Also, the toner conveyance inside the copying machine was good, and stable image density was obtained. O}The permeability was also good when the IP film was used.

Furthermore, the environment is low temperature and low humidity. An image printing test was conducted at high temperatures, but good results were obtained with no fogging and little toner scattering. Furthermore, even though the image obtained here was exposed to sunlight for 3 months, each color did not fade and was the same as when it was printed.

Broboxylated bisphenol. Ethoxylated bisphenol. Polyester resin obtained by condensing terephthalic acid and fumaric acid (Mn -2,100, M w = 18
,000, Tg=58℃, acid value=8,014 value=2
2) Perform the same procedure as in Example 1 using the above prescription amounts (Table 3) of the colorant and charge control agent per 100 parts by weight,
Classified toner products with the particle size distribution shown in Table 4 were prepared. As a fluidity improver, 0.5 parts by weight of silica fine powder treated with hexamethyldisilazane was externally added to 100 parts by weight of each classified toner product to prepare a full color toner.

(Left below) The carrier is a 50:50 mixture of vinylidene fluoride-tetrafluoroethylene copolymer (copolymerization weight ratio 8:2) and styrene-acrylic 2-ethylhexy-methyl methacrylate (copolymerization ratio 45:20:35). Cu-Zn-Fe coated with 0.7 wt% at a weight ratio of 50
Using a ferrite carrier (average particle size 49 μm; 250 mesh bath 400 mesh ion 93.5% by weight),
Developers were prepared so that the toner concentration for each color was 9% by weight. Using these developers and toners, an image reproduction test was conducted using a Canon full-color copying machine CLC-1. As a result, even after printing 13,000 sheets in full-color mode, there is no offset of the fixing roller, and a full-color image that faithfully reproduces the original color chart without fogging is obtained, and the black image area has excellent hiding properties. It had a deep black color.

Further, the toner transportability within the copying machine was good, and stable image density was obtained. Even when OHP film was used, toner permeability was very good. Further, image printing tests were carried out by changing the environment to low temperature and low humidity, high temperature and high temperature, and good results were obtained, with stable image density, no fogging, and almost no toner scattering.

The image obtained here was exposed to sunlight for 3 months, but each color did not fade and remained the same as when it was printed.

Comparative Example 1 As a colorant for magenta toner, C.I. I. Example 1 except that 1.7 parts by weight of Basic Violet 10 was used.
A classified magenta toner product was prepared in the same manner as above (volume average particle size: 8.02 μm; number average particle size: 6.21 μm (
a = 1.29). Number average distribution 5. 044
m or less 28.4%, volume average distribution 20.24 m or more 0.
1%). The classified toners of other colors were those used in Example 1.

Thereafter, a developer and toner were prepared in the same manner as in Example 1, and an image reproduction test was conducted using a full color copying machine CLC-1 manufactured by Canon.

As a result, good images without fogging were obtained even after printing 10,000 sheets in full color mode. Further, the toner transportability within the copying machine was good, and stable image density was obtained.

Even when OHP film was used, toner permeability was good. However, when performing an image output test by changing the environment to low temperature and low humidity, and high temperature and high temperature, it was found that the density of the magenta color decreased slightly and some fogging (toner scattering to non-image areas) was observed in low temperature and low humidity, and in high temperature and high temperature. The magenta toner was slightly scattered.

Furthermore, when the image obtained here was exposed to sunlight for three months, only the magenta color faded, resulting in a desaturated image with poor color reproduction.

Comparative Example 2 As a colorant for magenta toner, C.I. I. Pigment Red 206 3.5 parts by weight and C.I. without phenolic resin treatment. I. A classified magenta toner was prepared in the same manner as in Example 1, except that 1.4 parts by weight of Solvent Red 49 was used (volume average particle size: 8.22 μm; number average particle size: 6.35 gm (α=1.29) ).Number average distribution 5.04μm or less 29.2%, volume average distribution 20.
2μm or more 0.1%). The classified toners of other colors were those used in Example 1.

Thereafter, a developer and toner were prepared in the same manner as in Example 1, and an image reproduction test was conducted using a Canon full-color copying machine CLtl:-1. As a result, when images were produced in full-color mode, the color reproduction was reasonably good, but when images were produced in magenta single-color mode, the colorant was poorly dispersed and a mottled pattern appeared.

As a coloring agent for Arashihara ■dan magenta toner, C.I. I. A classified magenta toner product was prepared in the same manner as in Example 1, except that only 4.4 parts by weight of Pigment Red 206 was used (
Volume average particle size 8.07 μm. Number average particle size 6.30gm
(a - 1.28), number average distribution 5.04μ
m or less 31.1%, volume average distribution 20.2 μm or more 0.
1%). The classified toner of other colors was the one used in Example 1.

Thereafter, a developer and toner were prepared in the same manner as in Example 1, and an image reproduction test was conducted using a full color copying machine CLC-1 manufactured by Canon. As a result, the resulting image had low saturation and poor color reproducibility.

Taneku ■1 A developer and toner were prepared in the same manner as in Example 1, except that the particle sizes of magenta and cyan toner were prepared as shown in Table 5. (Hereinafter, blank space) In the same manner as in Example 1, Canon full color copying machine C
An image reproduction test was conducted using LC-1.

As a result, the in-flight scattering of magenta toner was very bad, and it adhered to the resulting image in a scattered state. Furthermore, the cyan toner had a very low density and poor fogging. Therefore, the obtained images had poor color reproduction and poor fogging.

[Effects of the Invention] As explained above, by the color image forming method of the present invention, an original color chart without offset and fog can be produced even after an image reproduction test, for example, after printing 15,000 sheets. You can obtain faithfully reproduced full-color images.

Furthermore, in the black image area, a deep black color with excellent concealment properties can be obtained.

In addition, the toner conveyance within the copying machine is good, stable image density can be obtained, and good images with almost no fog or toner scattering can be obtained even under low temperature, low humidity, high temperature and high temperature environments.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a full-color electrophotographic machine to which a color electrophotographic method according to the present invention is applied.

Claims (2)

[Claims] (1) In a color image forming method using multicolor electrophotography using magenta toner, cyan toner, yellow toner, and black toner, the magenta toner is a xanthene treated with a quinacridone pigment and a phenolic resin. The cyan toner is a toner having polyester resin particles containing a copper phthalocyanine blue pigment and a flow improver, and the yellow toner is a toner having a flow improver and polyester resin particles containing a copper phthalocyanine blue pigment. A toner comprising polyester resin particles containing a yellow pigment and a flow improver, the black toner being a toner comprising a polyester resin containing carbon black as a colorant and a flow improver. Formation method. (2) Jumping & development in which color toner adhering to the developing sleeve and carrier surface is transferred to the photosensitive drum for development.
2. The color image forming method according to claim 1, wherein a brush development method is used.