JP2954786B2 - Full color toner kit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-color toner kit used for forming a full-color image by an electrophotographic method.

[0002]

2. Description of the Related Art A full-color toner for electrophotography is basically a combination of a yellow toner, a magenta toner, a cyan toner and, if necessary, a black toner. 776
JP-A-53-47147 and JP-A-53-4717.
No. 5, JP-A-53-47176, and the like. Further, in recent years, as image forming apparatuses such as electrophotographic full-color copying machines have become widespread, the uses thereof have been expanded in a wide variety of ways, and the demand for image quality has become strict.
That is, in copying an image such as a general photograph, catalog, or map, it is required to reproduce extremely finely and faithfully without being crushed or interrupted even in a minute portion.

In an image forming apparatus such as a full-color copying machine for electrophotography, which recently uses a digital image signal, a latent image is formed by collecting dots of a constant potential, and a solid portion, a halftone portion and The light portion is expressed by changing the dot density. However, if the toner particles do not adhere to the dots and the toner particles protrude from the dots, the gradation of the toner image corresponding to the dot density ratio of the black portion and the white portion of the digital latent image cannot be obtained. There is. Furthermore, in order to improve the image quality, when reducing the dot size and improving the resolution,
Reproducibility of a latent image formed from minute dots becomes more difficult, and the image tends to be lacking in resolution and sharpness, particularly poor gradation in a highlight portion.

On the other hand, some developers have been proposed for the purpose of improving the image quality.
Part of this is to reduce the particle size of the toner.
JP-A-2-157051 discloses that the volume average particle size is 1 to 9 μm.
It has been proposed to use m color toners. However, when the volume average particle diameter of the toner is reduced, the cohesiveness of the toner increases. Therefore, in a so-called two-component developer that mixes a toner and a carrier that has been widely used in the past, some of the coagulated toner has Because there is a thing that can not obtain the desired charge amount because it can not contact the carrier enough,
The charge amount distribution becomes broad, which causes fogging and scattering.

Further, when the particle size of the toner is reduced, the specific surface area of the toner increases, so that the charge amount per unit mass, van der Waals force, and the like increase. For this reason, the adhesive force between the toner and the surface of the developer carrying member is increased, and charge-up occurs to contaminate the surface of the developer carrying member. For this reason, the toner that cannot sufficiently contact the surface of the developer carrying member cannot obtain a desired charge amount and causes fogging or the like. Further, there is a method of adding a fluidity-imparting agent in order to reduce the cohesiveness, but it is not preferable to add a large amount of the fluidity-imparting agent because it adversely affects environmental stability.

Next, a general image forming method for forming a full-color image, which has been conventionally performed, will be described. First, a photosensitive member of a photosensitive drum is uniformly charged by a primary charger, and a magenta image of an original is formed. Image exposure is performed by a laser beam modulated by an image signal to form an electrostatic latent image on a photosensitive drum. Next, the electrostatic latent image was developed by a magenta developing device having magenta toner, a developed magenta toner image was formed on a photosensitive drum, and the magenta toner image was conveyed by a transfer charger. Transfer to transfer material.

On the other hand, the photoreceptor drum after the development of the electrostatic latent image is discharged by a discharging charger, cleaned by cleaning means, and charged again by a primary charging device. Then, a cyan toner image is formed on the photosensitive drum, and subsequently, the cyan toner image is transferred to a transfer material on which the magenta toner image has been transferred. Further, the toner image of four colors is transferred onto the transfer material by sequentially performing the same process as described above for the yellow color and the black color. Therefore, in order to obtain a full-color image with good reproducibility under any environment, the charging characteristics of each color toner largely depend.

The transfer material having the toner images of the four colors obtained as described above is fixed to the transfer material by a fixing roller using heat, pressure or solvent vapor.
A copy is obtained. At present, as a fixing method used at that time, a fixing method using heat is mainly used in terms of fixing strength of the obtained copy, easiness of handling of the transferred matter, and work comfort. . As a heat fixing method, there is a method using radiant heat such as a heat chamber method, but a so-called heat roller fixing method in which a heated roll-shaped heating element is pressed against a toner image to fix the toner image has high thermal efficiency and high-speed compatibility. And it is adopted in most devices with high safety. However, although the efficiency is high, the energy used for fusing the sheet for thermal transfer occupies a considerable amount in an apparatus such as a copying machine, and
The disadvantage is that the toner adheres to the heat roll because it comes into direct contact with the fused toner image, and the so-called offset phenomenon, which stains the subsequent image, and, moreover, the so-called winding phenomenon, in which the fixing object wraps around the heat roll, is inevitable. is there.

Further, the toner used in the above-described toner image forming method needs to have good melting property and color mixing property when heat is applied thereto, and has a low softening point.
It is preferable to use a toner having a low melt viscosity and a high sharp melt property. That is, by using such a sharp melt toner, the color reproduction range of a copy can be expanded, and a color copy faithful to a document image can be obtained. However, such a color toner having a high sharp melt property has a high affinity with a fixing roller, and tends to be easily offset to the fixing roller during fixing. Especially in the case of a fixing device in a color image forming apparatus,
Since a plurality of toner layers of magenta, cyan, yellow and black are formed on the transfer material, offset tends to occur particularly.

Therefore, conventionally, a releasing agent such as silicone oil has been applied to the fixing roller in order to improve the releasability of the toner from the fixing roller. However, the image forming method coated with such a release agent has the following problems. That is,
In the current fixing system in which a releasing agent such as oil is applied to the roller, not only the configuration of the apparatus main body becomes complicated, but also the application of oil promotes the shortening of the service life of the fixing roller. . Further, in response to various copying needs in recent years, the passage of paper-like resin or the like has begun to be widely performed (generally, a film for an overhead projector, also known as a transparency film is well known). In the method, a sticky feeling due to oil application is inevitable, and a great problem remains in the quality of the obtained image. Therefore,
There is a great expectation for establishing such a fixing system that does not require oil application and for developing a new toner for achieving such a problem.

To solve the above problems, toners containing a release agent such as wax and suspension polymerization toners have been proposed (see Japanese Patent Publication No. 36-10231). This suspension polymerization method toner is prepared by uniformly dissolving or dispersing a polymerizable monomer and a colorant (and, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent and other additives). After the composition, the monomer composition is dispersed in a continuous phase (for example, an aqueous phase) containing a dispersion stabilizer using a suitable stirrer,
At the same time, a polymerization reaction is performed to obtain toner particles having a desired particle size. That is, in this suspension polymerization method, in order to generate droplets of the monomer composition in a dispersion medium having a large polarity of water, of the components contained in the monomer composition, the component having a polar group is It has a so-called pseudo-capsule structure in which non-polar components do not exist in the surface layer, while they are easily present in the surface layer at the interface with the aqueous phase. Therefore, if the characteristics of this manufacturing method are utilized, it is possible to make the toner contain a low melting point wax which cannot be used in other manufacturing methods such as a pulverizing method.

[0012] By incorporating a wax having a low melting point as described above, the toner obtained by the suspension polymerization method can achieve both contradictory performances of blocking resistance and low-temperature fixing. That is, since the low-melting wax is included in the toner, the thermal conductivity in the toner is improved due to the presence of the wax that can be melted at a low temperature without lowering the blocking resistance, and as a result, Low-temperature fixing becomes possible. More preferably, since the wax melted at the time of fixing also functions as a release agent, high-temperature offset can be prevented without applying a release agent such as oil to the fixing roller. However, with the recent increase in speed and energy saving of full-color copying machines, further low-temperature fixability and offset resistance of toner are required. Further, the present inventors, when the low-temperature melting wax in the suspension polymerization toner, a large amount of a wax component that can not be produced by a toner production method by ordinary kneading and pulverization, the usual, It has been found that a high-quality image can be obtained without any problem under an environment, but a phenomenon that when left in a high-temperature environment, developability is significantly reduced occurs.

[0013]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a full-color toner which solves the above-mentioned problems of the prior art. That is, an object of the present invention is to provide a full-color toner kit capable of providing a full-color image having high image density, excellent fine line reproducibility, and excellent highlight gradation. Another object of the present invention is to provide a full-color toner kit capable of providing a full-color image excellent in color reproducibility in any environment. Another object of the present invention is to provide a full-color toner kit which is excellent in low-temperature fixing property and offset resistance and excellent in environmental stability.

[0014]

The above objects are achieved by the present invention described below. That is, the present invention is a full-color image forming toner kit including at least a magenta toner, a cyan toner, a yellow toner, and a black toner, wherein a difference in work function between the respective color toners is 0.5 eV or less. .

[0015]

The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, focused on the work function of full-color toner, and found that the work function of each color toner of magenta, cyan, yellow, and black toners. The difference is 0.
It has been found that the use of a full-color toner kit of 5 eV or less can provide a full-color image excellent in color reproducibility in any environment, and completed the present invention. In addition, they have found that if the full-color toner is substantially spherical particles directly obtained by a suspension polymerization method, it is more preferable as a means for achieving the object of the present invention.
Further, as a means for achieving the object of the present invention more highly, the above-mentioned suspension polymerization method toner has a softening point of 30 to 110.
It has been found that it is effective to contain 5 to 50 wt% of a low-melting wax at a temperature of 5 ° C. and a polymerizable monomer content of 1000 ppm or less.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail with reference to preferred embodiments of the full-color toner kit of the present invention. As described above, a full-color image is obtained by individually developing at least four color (magenta, cyan, yellow, and black) toners. Therefore, in order to obtain a full-color image with good reproducibility, it is important to balance the charge properties of the four-color toner. That is, when the environmental stability of charging differs for each color, there is a possibility that an image having a different color reproducibility due to the environmental difference occurs. Therefore, the present inventors focused on the work function of the full-color toner, and at least the work function difference between the magenta toner, the cyan toner, the yellow toner, and the black toner was 0.5 eV.
By using the following full-color toner kit, it has been found that an image having excellent color reproducibility can be obtained under any environment. Here, the work function is an energy level of electrons specific to a substance, and it is considered that the difference in work function value is closely related to contact charging.

Next, in the present invention, the work function value (WF ₁
) Will be described. The measurement was made by Riken Keiki A
C-1S. FIG. 1 shows a schematic configuration diagram of an AC-1S device. As a UV light source, a xenon lamp light source of 1000 nW is used. The energy range of the monochromatic incident light is from 3.4 eV to 6.2 eV. The electrons emitted from the sample ionize oxygen in the air and are monitored by a low energy electron counter as ionized oxygen. Here, since the power of the quantum efficiency of the emitted photoelectrons is proportional to the energy of the incident light, a plot using the first law with high correlation is as shown in FIG. Then, A shown in FIG. 2 is obtained as a work function value unique to the substance.

The present inventors have further found that the object of the present invention can be more preferably achieved by using a full-color toner kit as a substantially spherical toner obtained directly by a suspension polymerization method. This is because the toner is substantially spherical, and the surface area per particle is close to the minimum, so that the influence of environmental differences is small, and the flowability is excellent and the charging speed is fast and easy to stabilize. it is conceivable that.

The present inventors have so far utilized suspension polymerization in an aqueous medium, taking advantage of the property that polymerization starts at the particle interface, polar components are concentrated near the interface, and nonpolar components are concentrated at the center. In addition, we have developed a suspension polymerization toner containing a large amount of wax components that cannot be produced by a toner production method that relies on ordinary kneading and pulverization. A toner that does not require the application of an agent is obtained. In the suspension polymerization method, for example, in the case of a styrene-acrylic vinyl polymerizable monomer, the amount of the polymerization initiator is 0.5 to 20% by weight, and the half-life of the initiator is 0.5.
When the polymerization temperature is set so as to be about 30 hours, a toner composition usable as a heat fixing toner can be obtained. Further, if the polymerization conversion rate becomes 90% or more under such a set condition, the toner particles do not coalesce and do not form a dough even if the stirring is stopped, so that the polymerization conversion rate becomes 97.8%. If it is taken out and dried when it reaches, it can be used as a toner without any problem.

However, if a large amount of low-melting wax is contained in such a suspension polymerization toner system, a high quality image can be obtained without any problem under a normal environment. A phenomenon that the developability was significantly reduced occurred. On the other hand, the present inventors, in order to further improve the environmental stability, regulate the residual solvent component of the suspension polymerization toner, in particular, the polymerizable monomer to 1000 ppm or less, and further, the work function difference of the toner of each full-color toner. To 0.
By combining the setting of 5 eV or less, a full-color toner kit having excellent environmental stability was obtained.

The minimum feature of the full-color toner kit of the present invention is to use a kit in which the four-color toner constituting the full-color toner has a work function difference of 0.5 eV or less. Hereinafter, a method for producing the toner used in the full-color toner kit of the present invention will be described, but the present invention is not limited thereto.

As described above, when the toner is manufactured by the suspension polymerization method, the low molecular weight component and the nonpolar component in the polymer are encapsulated in the center of the toner particle, and a pseudo capsule structure can be obtained. And low-temperature fixing, which are contradictory performances. On the other hand, in the suspension polymerization method, as the polymerization reaction proceeds, the viscosity of the polymerizable monomer system increases, and the movement of radical species and the polymerizable monomer becomes difficult,
Unreacted polymerizable monomers tend to remain in the system.

In the case of producing a toner by an ordinary pulverization method, the residual unreacted polymerizable monomer can be driven out by heat applied during the production of a binder resin for a toner or during melt-kneading. In the case of the suspension polymerization method toner for producing, since high heat cannot be applied, a large amount of polymerizable monomers will remain incorporated in the toner as compared with a normal pulverization method toner, The developability of the toner deteriorates. That is, when a large amount of such a polymerizable monomer is left at a high temperature in the absence of water by a suspension polymerization method in which the polymerizable monomer is incorporated in the toner, the unreacted polymerizable monomer is gradually reduced. It is considered that the low-molecular-weight component and the non-polar component, which are volatilized at the time of volatilization and are included at the time of volatilization, that is, the low-melting-point wax are conveyed to the surface portion and remain, thereby deteriorating the developing property of the toner. .

As the low melting point wax used in the full color toner kit of the present invention, a ring and ball method (JIS K25)
31) a softening point of 30 to 110 ° C., preferably 50
Those having a temperature of -100 ° C are desirable. If the temperature exceeds 110 ° C., it is difficult to achieve the purpose of low-temperature fixing, and if a large amount is used, granulation becomes difficult. On the other hand, if the temperature is lower than 30 ° C., it is difficult to hold the toner in the toner, it is easy to mix with the binder resin of the toner or the release agent applied to the fixing roller, and the viscosity becomes too low, and conversely, the release property is lowered. Is undesirably reduced. When the content of the low melting point wax as described above is 5 wt% or more, the effect on the fixability is exhibited, and the performance is improved with an increase in the use amount.
At 0 wt% or more, adverse effects such as uneven dispersion of the colorant in the toner, unstable granulation, and elution to the surface become remarkable. Therefore, the content is desirably 5 to 50 wt%, preferably 10 to 40 wt%. . In the production of the toner of the present invention, it is desirable that the type of wax is as non-polar as possible in order not to emulsify in water and to exist deep inside the toner.

The following are examples of the polymerizable monomer constituting the polymerizable monomer system and the toner property imparting agent such as a coloring agent used in the present invention. Examples of the polymerizable monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-methylstyrene.
Styrene monomers such as ethylstyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid Acrylic esters such as 2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, methacrylic acid
n-butyl, isobutyl methacrylate, methacrylic acid-
n-octyl, dodecyl methacrylate, methacrylic acid
2-ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate,
Examples include methacrylic esters such as diethylaminoethyl methacrylate and other monomers such as acrylonitrile, methacrylonitrile, and acrylamide. These monomers can be used alone or as a mixture. In addition, among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with another monomer from the viewpoint of the developing characteristics and durability of the toner.

In the present invention, polymerization may be carried out by adding a resin to the monomer system. For example, monomers cannot be used because they dissolve in aqueous suspensions and cause emulsion polymerization because they are water-soluble, such as amino groups, carboxylic acid groups, hydroxyl groups, sulfonic acid groups, glycidyl groups, and nitrile groups. When a hydrophilic functional group-containing monomer component is introduced into a toner, a copolymer such as a random copolymer, a block copolymer, or a graft copolymer thereof with a vinyl compound such as styrene or ethylene is used. Or in the form of a polycondensate such as polyester or polyamide, or a polyaddition conjugation such as polyether or polyimine.

The coexistence of such a high molecular polymer containing a polar functional group in the toner causes the above-mentioned wax component to phase-separate, the encapsulation becomes more powerful, and the performance of the toner intended in the present invention is improved. This is a preferred embodiment because it can be performed. The use amount is preferably 1 to 20 wt%. The average molecular weight of the high molecular polymer containing these polar functional groups is preferably 5,000 or more. When the molecular weight is 5,000 or less, particularly 4,000 or less, the high molecular polymer containing a polar functional group tends to concentrate near the surface, so that adverse effects on developability, blocking resistance, and the like are likely to occur, which is not preferable. Further, if a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the monomer is dissolved in the monomer and polymerized, a toner having a wide molecular weight distribution and higher offset resistance can be obtained. Can be done.

As the colorant used in the present invention, any known colorants can be used. For example, carbon black, iron black, C.I. I. Direct Red 1,
C. I. Basic Red 1, C.I. I. Modant Red 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 15, C.I. I.
Basic Blue 3, C.I. I. Basic Blue 5,
C. I. Modant Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6, graphite, cadmium yellow, mineral first yellow, navel yellow,
Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Tartrazine Lake, Millibden Orange GTR, Benzine Orange G, Cadmium Red 4
R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Navy Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green B, Malachite Green Rake, Final Yellow Green G and the like.

In the present invention, in order to obtain a toner using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and the water phase transfer property of the colorant. Is preferred. In particular, dyes and carbon black often have polymerization inhibitory properties, so care must be taken when using them. As a preferable method of surface-treating a dye system, a method of polymerizing a polymerizable monomer in the presence of these dyes in advance is exemplified. For carbon black, in addition to the same treatment as the above dye, it is also preferable to carry out a grafting treatment with a substance which reacts with the surface functional group of carbon black, for example, polyorganosiloxane or polyethylene glycol. Other pigments are less strong in inhibiting polymerization than carbon black, but it is better to perform the same treatment in consideration of dispersion in a polymerizable monomer.

The toner according to the present invention may contain a charge control agent to stabilize the charge characteristics. The charge control agent used at this time is preferably a colorless or light-colored charge control agent that does not affect the color tone of the toner.

The polymerization initiator used in the present invention includes:
When a polymer having a half life of 0.5 to 30 hours during the polymerization reaction is used in an amount of 0.5 to 20% by weight of the polymerizable monomer, a polymer having a maximum molecular weight of 10,000 to 100,000 is used. Can be obtained, and the desired strength and appropriate melting characteristics can be imparted to the toner. Specific examples of the polymerization initiator used include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, and 1,1′-azobis ( Cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-
Azo or diazo polymerization initiators such as 2,4-dimethylvaleronitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl par Peroxide-based polymerization initiators such as oxide and lauroyl peroxide; In the present invention, a crosslinking agent may be added, and a preferable addition amount is 0.001 to 15
% By weight.

In the method of producing the toner of the present invention, the above-mentioned toner composition, that is, a colorant, a release agent, a plasticizer, a binder, a charge control agent, a crosslinking agent, Components necessary as a toner such as a magnetic material and other additives, for example, an organic solvent to reduce the viscosity of the polymer formed by the polymerization reaction, a dispersant, etc. are appropriately added, and a homogenizer, a ball mill, a colloid mill The monomer system uniformly dissolved or dispersed by a disperser such as an ultrasonic disperser is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to quickly obtain the desired toner particle size.

The polymerization initiator may be added at the same time as the other additives are added to the polymerizable monomer, or may be mixed immediately before suspension in the aqueous medium. .
Immediately after granulation and before the initiation of the polymerization reaction, a polymerization initiator dissolved in a polymerizable monomer or a solvent can be added. After the granulation, stirring may be performed using a usual stirrer to such an extent that the particle state is maintained and the floating and settling of the particles are prevented.

In the suspension polymerization method of the present invention, known surfactants and organic and inorganic dispersants can be used as dispersion stabilizers. Among them, inorganic dispersants hardly generate harmful ultrafine powders. Since the dispersion stability is obtained due to the steric hindrance, the stability is hardly lost even if the reaction temperature is changed, the washing is easy, and the toner is not adversely affected. Examples of such inorganic dispersants include:
Polyphosphate metal salts such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate; carbonates such as calcium carbonate and barium carbonate; inorganic salts such as calcium metasilicate, calcium sulfate and barium sulfate; And inorganic oxides.

These inorganic dispersants can be used as polymerizable monomers 10
It is preferable to use 0.2 to 20 parts by weight alone with respect to 0 parts by weight. Further, when an inorganic dispersant is used, it is difficult to generate ultra fine particles, but it is slightly difficult to atomize the toner.
In this case, 0.001 to 0.1 part by weight of a surfactant may be used in combination. As the surfactant used at this time, for example, sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate,
Examples thereof include sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, and potassium stearate.

When these inorganic dispersants are used, commercially available ones may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles may be formed and used in an aqueous medium. . For example, in the case of potassium phosphate, a water-insoluble calcium phosphate can be produced by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring, and more uniform and fine dispersion can be achieved. At this time, a water-soluble sodium chloride salt is by-produced at the same time,
The presence of the water-soluble salt in the aqueous medium is more convenient because the dissolution of the polymerizable monomer in water is suppressed, and it becomes difficult to generate an ultrafine toner by emulsion polymerization. However, since it becomes an obstacle when removing the polymerizable monomer remaining at the end of the polymerization reaction, it is better to replace the aqueous medium or to desalt with an ion exchange resin. After the polymerization, the inorganic dispersant can be almost completely removed by dissolving with an acid or an alkali.

In the polymerization step, the polymerization temperature is 40
The polymerization is carried out at a temperature of at least 50 ° C., generally from 50 to 90 ° C. When the polymerization is carried out in this temperature range, the release agent and waxes to be sealed inside are broken out by phase separation, and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, the reaction temperature is 90 to 150 at the end of the polymerization reaction.
It is possible to raise to ° C. Under the above conditions, the conversion increases almost linearly up to a polymerization conversion of 90%,
At a polymerization conversion rate of 90% or more at which the toner is solidified, the increase in the degree of polymerization becomes slow, and at a polymerization conversion rate of 95% or more, it becomes extremely slow. Therefore, the polymerization reaction may proceed as it is, and the amount of the residual polymerizable monomer may be adjusted to 1,000 ppm or less, but various polymerizable monomer consumptions known in the conventional suspension polymerization method may be used. Accelerators can also be used.

For example, the means for promoting the consumption of the polymerizable monomer employed in the method for producing a suspension polymerization toner used in the full-color toner kit of the present invention may be 20 to 20% when the polymerization conversion reaches 95% or more. When the temperature is raised by 60 ° C., the viscosity is reduced by heat and the consumption of the polymerizable monomer is promoted by the initiation of thermal polymerization. At this time, if a polymerization initiator that decomposes at a high temperature is made to coexist in the polymer system, the polymerizable monomer can be more effectively consumed. Further, it is preferable to stop the reflux or reduce the pressure to partially remove the unreacted polymerizable monomer to reduce the residual amount to 1,000 ppm or less from the viewpoint of preventing aggregation of the formed toner.

Instead of holding in water, for example, the same effect as holding in water by exposing toner particles wetted with water to supersaturated water vapor while cooling water vapor to 40 to 50 ° C. While the remaining amount is 1,0
It can be as low as 00 ppm or less. In addition, as a method of consuming the polymerizable monomer by increasing the polymerization addition rate, an organic solvent which is a solvent of the toner is added to the polymer system, or a plasticizer is used in such an amount that the blocking resistance of the toner is not deteriorated. ,
There is a method of lowering the viscosity of the polymer system, for example, by adding the polymer system.

As a method for removing the unreacted polymerizable monomer, a method of washing with a highly volatile organic solvent which does not dissolve the toner binder resin but dissolves the polymerizable monomer,
There are a method of washing with an acid and an alkali, a method of adding a solvent component that does not dissolve a foaming agent and a polymer to a polymer system, and increasing the volatilization area of the polymerizable monomer inside by making the obtained toner porous. However, it is difficult to select a solvent due to problems such as elution of toner components and persistence of the solvent.
The method of volatilizing the polymerizable monomer under reduced pressure is most preferable. In the manner described above, finally, the amount of the polymerizable monomer is at least 1000 ppm or less, and in order to eliminate the odor due to the polymerizable monomer and its reaction residue generated at the time of fixing or the solvent, it is more preferable. Is 100 ppm or less.

The polymerization conversion was measured by an internal standard method under the following conditions by gas chromatography using a solution prepared by adding a polymerization inhibitor to 1 g of the suspension and dissolving it in 4 ml of THF. The amount of the residual polymerizable monomer and residual organic solvent was determined by dissolving 0.2 g of the toner in 4 ml of THF by gas chromatography under the following conditions using an internal standard method.

[0042]

When the toner used in the full-color toner kit of the present invention is manufactured, the additives added for the purpose of imparting various characteristics include a volume average particle size of the toner particles from the viewpoint of durability when added to the toner. It is preferable that the particle diameter is 1/10 or less of the diameter. The particle size of the additive means an average particle size obtained by observing the surface of the toner particles with an electron microscope.

As the additives for imparting these properties, for example, the following are used. (1) Fluidity imparting agents: metal oxides (such as silicon oxide, aluminum oxide, and titanium oxide), carbon black, and carbon fluoride. Those subjected to a hydrophobic treatment are more preferable. (2) Abrasive: metal oxide (strontium titanate,
Cerium oxide, aluminum oxide, magnesium oxide,
Chromium oxide, etc., nitrogen (silicon nitride, etc.), carbide (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.). (3) Lubricants: fluororesin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.) and the like. (4) Charge controllable particles: metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.), carbon black and the like. These additives are used in the toner particles 100
0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, is used based on parts by weight. These additives may be used alone or in combination of two or more. However, in the four-color full-color toner kit of the present invention, it is necessary that the combination be such that the color difference between each color is 0.5 eV. I do.

[0045]

Next, the present invention will be described more specifically with reference to examples and comparative examples. All parts are parts by weight.
Examples 1 to 3 and Comparative Examples 1 to 3 Table 1 shows the binder resins, low melting point waxes, types of external additives, production methods and residuals used in Examples 1 to 3 and Comparative Examples 1 to 3. And the work function differences between the obtained monomer amounts and the four full-color kits obtained.

[0046]

[Table 1]

Evaluation 1 Using these full-color kits obtained in Examples 1 to 3 and Comparative Examples 1 to 3, an image output test was performed using a CLC500 (manufactured by Canon) remodeling machine. Table 2 shows the obtained evaluation results.

[0048]

[Table 2]

However, the following pigments were used as colorants in each color toner.・ Magenta toner: Rhodamian lake ・ Cyan toner: Phthalocyanine blue ・ Yellow toner: Benzicin yellow ・ Black toner: Carbon black

The suspension polymerization method toners of Examples and Comparative Examples of the present invention were produced in accordance with the following toner production example of Example 2. Example of toner production 710 g ion-exchanged water
The 0.1M-Na ₃ PO ₄ aqueous solution 450g was charged into a 60
After heating to ° C., 67 g of 1.0 M CaCl ₂ was gradually added to obtain an aqueous medium containing Ca (PO ₄ ) ₂ . ·styrene
170g ・ n-BA
30g ・ St-MA-MMA resin (Mw = 30,000)
3g ・ paraffin wax (sp = 70 ° C, ΔH = 47ca)
1 / g) 50 g ・ Chromium compound di-t-butylsalicylate
5g ・ Phthalocyanine blue
10 g The above formulation was heated to 60 ° C. and uniformly dispersed and dissolved using Ebara Paramilder (manufactured by Shobara Sakusho). To this, 10 g of a polymerization initiator (peroxide) was added to prepare a polymerizable monomer.

The polymerizable monomer system was charged into the aqueous medium, and the mixture was stirred at 60 ° C. under a N ₂ atmosphere with a TK homomixer at 10,000 rpm for 20 minutes. Granulated. Thereafter, the mixture was reacted at 60 ° C. for 0.5 hour while stirring with a paddle stirring blade. At this time, the polymerization conversion was 65%. Thereafter, the reflux of the steam was stopped, the liquid temperature was set to 80 ° C., and stirring was continued for another 10 hours. After completion of the reaction, the suspension was cooled,
a ₃ (PO ₄ ) ₂ was dissolved, filtered, washed with water and dried to obtain a suspension polymerization toner having a weight average diameter of 8.2 μm. This toner was subjected to a degassing treatment at 45 ° C. under a reduced pressure of 50 mmHg for 12 hours. At this time, the amount of the remaining polymerizable monomer was 120 ppm.

With respect to 100 parts by weight of the obtained toner, B
0.7 parts by weight of hydrophobic silica (treated with a silane coupling agent) having a specific surface area of 200 m ² / g by the ET method was added. To 7 parts by weight of this externally added toner, 93 parts by weight of a ferrite carrier coated with an acrylic resin were mixed to prepare a developer. Similarly, by changing the above-mentioned pigment as a coloring agent, four full-color toners were obtained. The work function difference (the difference between the maximum and the minimum) of these toners is 0.15 e
V.

[0053]

As described above, if the full-color toner kit of the present invention is used, in any environment,
A full-color image with excellent color reproducibility can be obtained. When the full-color toner kit of the present invention is used, a full-color image having high image density, excellent fine line reproducibility, and excellent highlight gradation can be obtained. Further, the full-color toner kit of the present invention has excellent low-temperature fixability and offset resistance, and
It has excellent environmental stability.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an AC-1S device used for measuring a work function value.

FIG. 2 is a diagram illustrating basic characteristics of a work function value.

Continued on the front page (72) Inventor Makoto Kambayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Koji Inaba 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-61-99158 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. A full-color image forming toner kit comprising at least a magenta toner, a cyan toner, a yellow toner and a black toner, wherein a difference in work function between the respective color toners is 0.5 eV or less. 2. The full-color toner kit according to claim 1, wherein the full-color toner is substantially spherical particles directly obtained by a suspension polymerization method. 3. A low melting point wax having a softening point of 30 to 110 ° C. is contained in an amount of 5 to 50% by weight and a polymerizable monomer content is 1%.
The full-color toner kit according to claim 1, wherein the amount is 000 ppm or less.